HB-17_3

Division I-ASEISMIC DESIGN

© 2002 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.

Section 1INTRODUCTION

1.1 PURPOSE AND PHILOSOPHY

These Specifications establish design and constructionprovisions for bridges to minimize their susceptibility todamage from earthquakes.

The design earthquake motions and forces specified inthese provisions are based on a low probability of theirbeing exceeded during the normal life expectancy of abridge.1 Bridges and their components that are designedto resist these forces and that are constructed in accor-dance with the design details contained in the provisionsmay suffer damage, but should have low probability ofcollapse due to seismically induced ground shaking.

The principles used for the development of the provi-sions are:

1. Small to moderate earthquakes should be resistedwithin the elastic range of the structural componentswithout significant damage.2. Realistic seismic ground motion intensities andforces are used in the design procedures.3. Exposure to shaking from large earthquakes shouldnot cause collapse of all or part of the bridge. Wherepossible, damage that does occur should be readily de-tectable and accessible for inspection and repair.

A basic premise in developing these seismic designguidelines was that they are applicable to all parts of theUnited States. The seismic hazard varies from very smallto high across the country. Therefore, for purposes of de-sign, four Seismic Performance Categories (SPC) are de-fined on the basis of an Acceleration Coefficient (A) for thesite, determined from the map provided, and the Impor-tance Classification (IC). Different degrees of complexityand sophistication of seismic analysis and design are spec-ified for each of the four Seismic Performance Categories.

An essential bridge must be designed to function dur-ing and after an earthquake. In areas with an Acceleration

Coefficient greater than 0.29 essential bridges must meetadditional requirements. A bridge is designated essentialon the basis of Social/Survival and Security/Defense clas-sifications presented in the Commentary.

1.2 BACKGROUND

The 1971 San Fernando earthquake was a major turn-ing point in the development of seismic design criteria forbridges in the United States. Prior to 1971, the AmericanAssociation of State Highway and Transportation Offi-cials (AASHTO) specifications for the seismic design ofbridges were based in part on the lateral forces require-ments for buildings developed by the Structural EngineersAssociation of California. In 1973, the California Depart-ment of Transportation (CalTrans) introduced new seis-mic design criteria for bridges, which included the rela-tionship of the site to active faults, the seismic response ofthe soils at the site and the dynamic response characteris-tics of the bridge. In 1975, AASHTO adopted InterimSpecifications which were a slightly modified version ofthe 1973 CalTrans provisions, and made them applicableto all regions of the United States. In addition to thesecode changes, the 1971 San Fernando earthquake stimu-lated research activity on seismic problems related tobridges. In the light of these research findings, the FederalHighway Administration awarded a contract in 1978 tothe Applied Technology Council (ATC) to:

• Evaluate current criteria used for seismic design ofhighway bridges.

• Review recent seismic research findings for designapplicability and use in new specifications.

• Develop new and improved seismic design guide-lines for highway bridges applicable to all regions ofthe United States.

• Evaluate the impact of these guidelines and modifythem as appropriate.

The guidelines from this ATC project (known as ATC-6) were first adopted by AASHTO as a set of Guide

439

1The probability of the elastic design force levels not being exceededin 50 years is the range of 80 to 95%. However, the design earthquakeforce level by itself does not determine risk; the risk is also affected bythe design rules and analysis procedures used in connection with the de-sign ground motion.


Specifications in 1983. They were later adopted as seis-mic provisions within the Standard Specifications in1990. After damaging earthquakes occurred in California(1989), Costa Rica (1991) and the Philippines (1991),AASHTO requested the Transportation Research Boardto review these criteria and prepare revised specificationsas appropriate. Funded through the National CooperativeHighway Research Program under NCHRP Project 20-7/45, the National Center for Earthquake Engineering Re-search (NCEER) prepared this current set of seismic de-sign provisions. They closely follow the previous criteriabut remove ambiguities and technical errors, correct tech-nical omissions and introduce new material which isbased in part on recent field experience and partly on newresearch findings. In addition, a new format is introducedso as to assist the application of these specifications tobridges in different seismic zones.

1.3 BASIC CONCEPTS

The development of these specifications was predi-cated on the following basic concepts.

• Hazard to life to be minimized.• Bridges may suffer damage but have low probabil-

ity of collapse due to earthquake motions.• Function of essential bridges to be maintained.• Ground motions used in design should have low

probability of being exceeded during normal life-time of bridge.

• Provisions to be applicable to all of the UnitedStates.

• Ingenuity of design not to be restricted.

1.4 PROJECT ORGANIZATION

The ATC-6 project was advised by a Project Engineer-ing Panel comprising the following members:

• Mr. James Cooper, Federal Highway Administra-tion; Mr. Gerard Fox, HNTB, New York; Mr. JamesH. Gates, California Department of Transportation;Mr. Veldo Goins, Oklahoma Department of Trans-portation; Dr. William Hall, University of Illinois,Urbana; Mr. Edward Hourigan, New York Depart-ment of Transportation; Mr. Robert Jarvis, Idaho De-partment of Transportation; Mr. Robert Kealey,Modjeski and Masters, Harrisburg; Mr. JamesLibby, Libby Engineers, San Diego; Dr. GeoffreyMartin, Fugro Inc., Long Beach; Mr. Joseph Nico-letti, URS Blume, San Francisco; Dr. Joseph Pen-

zien, University of California, Berkeley; Dr. WalterPodolny, Federal Highway Administration; and Dr.Robert Scanlan, Princeton University, New Jersey.

The ATC project manager and technical director wereMr. Roland Sharpe and Dr. Ronald Mayes, respectively.

In a similar manner, the NCHRP project was alsoguided by a Project Panel. The members were:

• Mr. James D. Cooper, Federal Highway Administra-tion; Mr. James H. Gates, California Department ofTransportation; Mr. Veldo Goins, Oklahoma Depart-ment of Transportation; Mr. Ayaz Malik, New YorkDepartment of Transportation; Mr. Charles Ruth,Washington Department of Transportation; and Mr.Edward Wasserman, Tennessee Department ofTransportation.

• Liaison members were Dr. John Kulicki, Modjeskiand Masters (NCHRP 12-33 Liaison) and Dr. WalterPodolny (Federal Highway Administration Liaison).

• The principal investigator for NCEER was Dr. IanBuckle; subcontractors included Computech Engi-neering Services, Berkeley, CA, and Imbsen and As-sociates, Sacramento, CA.

• NCHRP Project Officers were Mr. Ian Friedland andMr. Scott Sabol.

The work was conducted in several stages:

• Review of 1992 Standard Specifications (Division I-A); survey of designer experience with the ap-plication of Division I-A and evaluation of designphilosophy.

• Review of bridge performance in recent earth-quakes.

• Review of revised CalTrans seismic design criteria(ATC-32 project).

• Review of seismic criteria in the proposed LRFDBridge Specification (NCHRP 12-33).

• Conduct of certain special studies.• Development of draft revisions in various formats of

increasing complexity.• Evaluation of proposed revisions.• Modification and preparation of final standards, as

appropriate.

1.5 QUALITY ASSURANCE REQUIREMENTS

There are numerous instances of structural failureswhich have occurred during earthquakes that are directlytraceable to poor quality control during construction. Theliterature is replete with reports noting that collapse mayhave been prevented had proper inspection been exer-

440 HIGHWAY BRIDGES 1.2


cised. To provide adequate seismic quality assurance re-quirements the engineer specifies the quality assurance re-quirements, the contractor exercises the control to achievethe desired quality and the owner monitors the construc-tion process through special inspection. It is essential thateach party recognizes its responsibilities, understands theprocedures and has the capability to carry them out. Be-cause the contractor does the work and exercises qualitycontrol it is essential that the inspection be performed bysomeone approved by the owner and not the contractor’sdirect employee.

In recognition of the fact that responsibility must becoordinated during construction, the Project Engineering

Panel (PEP) for the ATC-6 project examined the respon-sibility of each party in the current AASHTO (Division I)specifications. This PEP found the quality assurance re-quirements of the Division I specifications adequate tocover seismic as well as other design requirements. There-fore, no special quality assurance requirements are in-cluded in Division I-A.

1.6 FLOW CHARTS

Flow charts outlining the steps in the seismic designprocedures implicit in these specifications are given inFigures 1.6A and 1.6B.

1.5 DIVISION IA—SEISMIC DESIGN 441



FIGURE 1.6A Design Procedure Flow Chart



FIGURE 1.6B Sub Flow Chart for Seismic PerformanceCategories B, C, and D


445

Section 2SYMBOLS AND DEFINITIONS

2.1 NOTATIONS

The following symbols and definitions apply to these Specifications:

a � Vertical spacing of transverse reinforcement (hoops or stirrups) in rectangular reinforced concretecolumns (in. or mm)

A � Acceleration coefficient determined in Article 3.2 (dimensionless)Ac � Area of reinforced concrete column core (in.2 or mm2)Ag � Gross area of reinforced concrete column (in.2 or mm2)As � Area of longitudinal reinforcement in a concrete pile (in.2 or mm2)Ash � Total cross-sectional area of transverse reinforcement (hoops or stirrups) used in rectangular rein-

forced concrete columns (in.2 or mm2) and defined by Equations (6–6), (6–7), (7–6), and (7–7)Avf � Total amount of reinforcement normal to a construction joint (in.2 or mm2)B � Loads resulting from buoyancy forces and used in the group load combinations of Equations (6–1),

(6–2), (7–1), and (7–2)Cm � Coefficient used in steel design to account for boundary conditions (dimensionless)Cs � Elastic seismic response coefficient defined in Article 3.6.1 (dimensionless)Csm � Elastic seismic response coefficient for mode “m” defined in Article 3.6.2 (dimensionless)d � Diameter of a reinforced concrete column (in. or mm)D � Loads resulting from dead load and used in the group load combinations of Equations (6–1), (6–2),

(7–1), and (7–2)E � Loads resulting from earth pressure and used in the group load combinations of Equations (6–1),

(6–2), (7–1), and (7–2)EQF � Modified foundation seismic forces used in the group load combination of Equations (6–2) and (7–2),

and defined in Articles 6.2.2 and 7.2.1EQM � Modified seismic forces used in the group load combination of Equations (6–1) and (7–1), and de-

fined in Articles 6.2.1 and 7.2.1fc� � Specified compressive strength of reinforced concrete (psi or MPa)fy � Yield strength of reinforcement in reinforced concrete members (psi or MPa)fyh � Yield strength of transverse reinforcement (psi or MPa)Fa � Axial stress in steel design that would be permitted if axial force alone existed (psi or MPa)Fcr � Buckling stress for load factor steel design (psi or MPa)Fe � Euler buckling stress in the plane of bending (psi or MPa)Fe� � Euler buckling stress for service load steel design (psi or MPa)Fy � Yield strength of structural steel (psi or MPa)g � Acceleration of gravity (in./sec2 or cm/sec2)hc � Core dimension of a rectangular reinforced concrete column (in. or mm)H � Height of a column or pier defined in Articles 5.3, 6.3, and 7.3 (ft or m)IC � Importance Classification given in Article 3.3 (dimensionless)K � Total lateral stiffness of bridge as defined in Article 4.3 (lb/in. or kN/m)K � Effective length factor used in steel design and given in Articles 6.5 and 7.5 (dimensionless)kh � Seismic coefficient used to calculate lateral earth pressures and defined in Articles 6.4.3 and 7.4.3

(dimensionless)



L � Length of bridge deck defined in Articles 4.3, 5.3, 6.3, and 7.3 (ft or m)N � Minimum support length for girders specified in Articles 3.10, 5.3, 6.3, and 7.3 (in. or mm)pe(x) � Intensity of the equivalent static seismic loading applied to represent the primary mode of vibration

in Articles 4.3 and 4.4 (force/unit length)Pn � Minimum axial load specified in Article 7.2.3 for columns and 7.2.4 for piers (lb or N)po � Assumed uniform loading used to calculate the period in Articles 4.3 and 4.4 (force/unit length)Q � Vertical force at a support due to longitudinal horizontal seismic loads (lb or N)R � Response modification factor specified in Article 3.7 (dimensionless)S � Site coefficient specified in Article 3.5.1 (dimensionless)S � Angle of skew of girder support as defined in Articles 5.3 and 6.3 (degrees)SF � Loads resulting from stream flow forces and used in the group load combinations of Equations (6–1),

(6–2), (7–1), and (7–2)SPC � Seismic Performance Category specified in Article 3.4 (dimensionless)T � Fundamental period of the bridge determined in Articles 4.3 and 4.4 (sec.)Tm � Period of the mth mode of vibration of a bridge (sec.)Vc � Nominal shear strength provided by concrete as specified in Article 7.6.2(C)Vj � Limiting shear force across a construction joint (lb or N)vu � Shear stress (psi or MPa)Vu � Shear force (lb or N)vs(x), ve(x) � Static displacement profiles resulting from applied loads po and pe, respectively, and used in Articles

4.3 and 4.4 (in. or mm)w(x) � Dead weight of the bridge superstructure and tributary substructure per unit length (force/unit length)W � Total dead weight of bridge superstructure and tributary substructure (lb or kN)�h � The ratio of horizontal shear reinforcement area to gross concrete area of a vertical section—Article

7.6.3 (dimensionless)�n � The ratio of vertical shear reinforcement area to the gross concrete area of a horizontal section—

Article 7.6.3 (dimensionless)�s � Volumetric ratio of spiral reinforcement for a circular column (dimensionless)� � Strength reduction factor (dimensionless)� � Coefficient used to calculate the period of the bridge in Article 4.4 (length2)� � Coefficient used to calculate the period of the bridge in Article 4.4 (force � length)� � Coefficient used to calculate the period of the bridge in Article 4.4 (force � length2)


447

Section 3GENERAL REQUIREMENTS

3.1 APPLICABILITY OF SPECIFICATIONS

These Specifications are for the design and constructionof new bridges to resist the effect of earthquake motions.The provisions apply to bridges of conventional steel andconcrete girder and box girder construction with spans notexceeding 500 feet (150 meters). Suspension bridges,cable-stayed bridges, arch type and movable bridges arenot covered by these Specifications. Seismic design is usu-ally not required for buried type (culvert) bridges.

The provisions contained in these Specifications areminimum requirements.

No detailed seismic analysis is required for any singlespan bridge or for any bridge in Seismic Performance Cat-egory A. For single span bridges (Article 3.11) andbridges classified as SPC A (Section 5) the connectionsmust be designed for specified forces and must also meetminimum support length requirements.

3.2 ACCELERATION COEFFICIENT

The Acceleration Coefficient (A) to be used in the ap-plication of these provisions shall be determined from thecontour maps of Figures 3.2A and 3.2B. (Note: An en-

FIGURE 3.2A Acceleration Coefficient—Continental United States(An enlarged version of this map, including counties, is given at the end of Division—I-A.)



FIGURE 3.2B Acceleration Coefficient—Alaska, Hawaii, and Puerto Rico



larged version of Figure 3.2A is given at the end of Divi-sion I-A.) Values given in Figures 3.2A and 3.2B are ex-pressed in percent. Numerical values for the coefficient Aare obtained by dividing contour values by 100.0. Localmaxima (and minima) are given inside the highest (andlowest) contour for a particular region. Linear interpola-tion shall be used for sites located between contour linesand between a contour line and local maximum (or mini-mum). The seismic loads represented by the accelerationcoefficients in Figures 3.2A and 3.2B have a 10% proba-bility of exceedance in 50 years (which is approximatelyequivalent to a 15% probability of exceedance in 75years). This corresponds to a return period of approxi-mately 475 years. Special studies to determine site- andstructure-specific acceleration coefficients shall be per-formed by a qualified professional if any one of the fol-lowing conditions exist:

(a) The site is located close to an active fault.(b) Long duration earthquakes are expected in the region.(c) The importance of the bridge is such that a longerexposure period (and therefore return period) shouldbe considered.

The effect of soil conditions at the site are consideredin Article 3.5.

3.3 IMPORTANCE CLASSIFICATION

An Importance Classification (IC) shall be assigned forall bridges with an Acceleration Coefficient greater than0.29 for the purpose of determining the Seismic Perfor-mance Category (SPC) in Article 3.4 as follows:

1. Essential bridges � IC � I2. Other bridges � IC � II

Bridges shall be classified on the basis of Social/Sur-vival and Security/Defense requirements, guidelines forwhich are given in the Commentary.

3.4 SEISMIC PERFORMANCE CATEGORIES

Each bridge shall be assigned to one of four SeismicPerformance Categories (SPC), A through D, based on theAcceleration Coefficient (A) and the Importance Classifi-cation (IC), as shown in Table 3.4. Minimum analysis anddesign requirements are governed by the SPC.

3.5 SITE EFFECTS

The effects of site conditions on bridge response shallbe determined from a Site Coefficient (S) based on soilprofile types defined as follows:

SOIL PROFILE TYPE I is a profile with either—

1. Rock of any characteristic, either shale-like orcrystalline in nature (such material may be character-ized by a shear wave velocity greater than 2,500feet/seconds (760 meters/seconds), or by other appro-priate means of classification); or2. Stiff soil conditions where the soil depth is less than200 feet (60 meters) and the soil types overlying rockare stable deposits of sands, gravels, or stiff clays.

SOIL PROFILE TYPE II is a profile with stiff clay ordeep cohesionless conditions where the soil depth exceeds200 feet (60 meters) and the soil types overlying rock arestable deposits of sands, gravels, or stiff clays.

SOIL PROFILE TYPE III is a profile with soft to medium-stiff clays and sands, characterized by 30 feet(9 meters) or more of soft to medium-stiff clays with orwithout intervening layers of sand or other cohesionlesssoils.

SOIL PROFILE TYPE IV is a profile with soft clays orsilts greater than 40 feet (12 meters) in depth. These mate-rials may be characterized by a shear wave velocity lessthan 500 feet/seconds (150 meters/seconds) and might in-clude loose natural deposits or synthetic, nonengineered fill.

In locations where the soil properties are not known insufficient detail to determine the soil profile type withconfidence, the Engineer’s judgement shall be used to se-lect a site coefficient from Table 3.5.1 that conservativelyrepresents the amplification effects of the site. The soilprofile coefficients apply to all foundation types includingpile supported and spread footings.

A site coefficient need not be explicitly identified if asite-specific seismic response coefficient is developed bya qualified professional (Article 3.6).

3.5.1 Site Coefficient

The Site Coefficient (S) approximates the effects of thesite conditions on the elastic response coefficient or spec-trum of Article 3.6 and is given in Table 3.5.1.

TABLE 3.4 Seismic Performance Category (SPC)



3.6 ELASTIC SEISMIC RESPONSECOEFFICIENT

A seismic response coefficient is specified in this Arti-cle which defines the earthquake load to be used in theelastic analysis for seismic effects.

These requirements may be superseded by a 5%damped, site-specific, response spectrum developed by a qualified professional. Such a spectrum shall include the effects of both the local seismology and the site soilconditions.

3.6.1 Elastic Seismic Response Coefficient forSingle Mode Analysis

The elastic seismic response coefficient Cs used to de-termine the design forces is given by the dimensionlessformula:

Cs � (3-1)

where,

A � the Acceleration Coefficient from Article 3.2,

S � the dimensionless coefficient for the soil profile characteristics of the site as given in Article 3.5,

T � the period of the bridge as determined in Articles 4.3 and 4.4 or by other acceptablemethods.

The value of Cs need not exceed 2.5A. For Soil ProfileType III or Type IV soils in areas where A � 0.30, Cs neednot exceed 2.0A.

3.6.2 Elastic Seismic Response Coefficient forMultimodal Analysis

The elastic seismic response coefficient for mode “m,”Csm, shall be determined in accordance with the followingformula:

Cs � (3-2)

where Tm � the period of the mth mode of vibration.

The value of Csm need not exceed 2.5A. For Type III orType IV soils in areas where the coefficient A � 0.30, Csm

need not exceed 2.0A.

EXCEPTIONS:

1. For Soil Profile Type III or Type IV soils, Csm formodes other than the fundamental mode which haveperiods less than 0.3 seconds may be determined in ac-cordance with the following formula:

Csm � A(0.8 � 4.0Tm) (3-3)

2. For structures in which any Tm exceeds 4.0 seconds,the value of Csm for that mode may be determined inaccordance with the following formula:

Cs � (3-4)

3.7 RESPONSE MODIFICATION FACTORS

Seismic design forces for individual members and con-nections of bridges classified as SPC B, C, or D are deter-mined by dividing the elastic forces by the appropriateResponse Modification Factor (R) as specified in Article6.2 or 7.2. The Response Modification Factors for variousbridge components are given in Table 3.7. These factorsshall only be used when all of the design requirements ofSections 6 and 7 are satisfied. If these requirements are notsatisfied, the maximum value of R for substructures andconnections shall be 1.0 and 0.8, respectively.

3.8 DETERMINATION OF ELASTIC FORCESAND DISPLACEMENTS

For bridges classified as SPC B, C, or D the elasticforces and displacements shall be determined indepen-dently along two perpendicular axes by use of the analy-sis procedure specified in Article 4.2. The resulting forcesshall then be combined as specified in Article 3.9. Typi-cally, the perpendicular axes are the longitudinal andtransverse axes of the bridge but the choice is open to thedesigner. The longitudinal axis of a curved bridge may bea chord connecting the two abutments.

3.9 COMBINATION OF ORTHOGONALSEISMIC FORCES

A combination of orthogonal seismic forces is used to account for the directional uncertainty of earthquake

3AS�Tm

4/3

1.2AS�

Tm2/3

1.2AS�

T2/3

TABLE 3.5.1 Site Coefficient (S)



motions and the simultaneous occurrences of earthquakeforces in two perpendicular horizontal directions. Theelastic seismic forces and moments resulting from analy-ses in the two perpendicular directions of Article 3.8 shallbe combined to form two load cases as follows:

LOAD CASE 1: Seismic forces and moments on eachof the principal axes of a member shall be obtained byadding 100% of the absolute value of the member elasticseismic forces and moments resulting from the analysis inone of the perpendicular (longitudinal) directions to 30%of the absolute value of the corresponding member elas-tic seismic forces and moments resulting from the analy-sis in the second perpendicular direction (transverse).(NOTE: The absolute values are used because a seismicforce can be positive or negative.)

LOAD CASE 2: Seismic forces and moments on each ofthe principal axes of a member shall be obtained by adding100% of the absolute value of the member elastic seismicforces and moments resulting from the analysis in the sec-ond perpendicular direction (transverse) to 30% of the ab-solute value of the corresponding member elastic seismicforces and moments resulting from the analysis in the firstperpendicular direction (longitudinal).

EXCEPTION:For SPC C and D when foundation and/or column con-nection forces are determined from plastic hinging ofthe columns (Article 7.2.2) the resulting forces neednot be combined as specified in this section. If a pier is

designed as a column per Article 7.2.4 this exceptiononly applies for the weak direction of the pier whenforces resulting from plastic hinging are used. Thecombination specified must be used for the strong di-rection of the pier.

3.10 MINIMUM SEAT-WIDTH REQUIREMENTS

All bridges, regardless of Seismic Performance Cate-gory (SPC) and number of spans, shall satisfy minimumsupport length requirements at the expansion ends of allgirders. These support lengths are defined in Figure 3.10as dimension N. The minimum value for N is given forSPC A in Article 5.3; for SPC B in Article 6.3; and for SPCC and D in Article 7.3.

3.11 DESIGN REQUIREMENTS FOR SINGLESPAN BRIDGES

The detailed analysis and design requirements of Sec-tions 4, 5, 6, and 7 are not required for single span bridges.In lieu of rigorous analysis, the connections between thebridge span and the abutments shall be designed to resistthe tributary weight at the abutment multiplied by the Ac-celeration Coefficient and the Site Coefficient for the site.This force must be considered to act in each horizontallyrestrained direction. The minimum support lengths shallbe as specified in Article 3.10.

TABLE 3.7 Response Modifications Factor (R)



3.12 REQUIREMENTS FOR TEMPORARYBRIDGES AND STAGED CONSTRUCTION

The requirement that an earthquake shall not cause col-lapse of all or part of a bridge as stated in Article 1.1, ap-plies to temporary bridges which are expected to carrytraffic and/or pass over routes that carry traffic. It also ap-plies to those bridges that are constructed in stages and ex-pected to carry traffic and/or pass over routes that carrytraffic. However, in view of the limited exposure period,the Acceleration Coefficient given in Article 3.2 may bereduced by a factor of not more than 2 in order to calcu-late the component elastic forces and displacements. Note

that Acceleration Coefficients for construction sites thatare close to active faults shall be the subject of specialstudy. Further, the Response Modification Factors givenin Article 3.7 may be increased by a factor of not morethan 1.5 in order to calculate the design forces. This factor shall not be applied to connections as defined inTable 3.7.

The minimum seat-width provisions of Article 3.10 shallapply to all temporary bridges and staged construction.

Any bridge or partially constructed bridge that is ex-pected to be temporary for more than 5 years shall be de-signed using the requirements for permanent structuresand shall not use the provisions of this article.

FIGURE 3.10 Dimensions for Minimum Support Length Requirements


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Section 4ANALYSIS REQUIREMENTS

4.1 GENERAL

The requirements of this section shall control the se-lection and method of seismic analysis of bridges. Fouranalysis procedures are presented.

Procedure 1. Uniform Load MethodProcedure 2. Single-Mode Spectral MethodProcedure 3. Multimode Spectral MethodProcedure 4. Time History Method

In each method, all fixed column, pier, or abutmentsupports are assumed to have the same ground motion atthe same instant in time. At movable supports, displace-ments determined from the analysis prescribed in thischapter, which exceed the minimum seat width require-ments as specified in Article 6.3 or 7.3, shall be used indesign without reduction by the Response ModificationFactor (Article 3.7).

4.2 SELECTION OF ANALYSIS METHOD

Minimum requirements for the selection of an analysismethod for a particular bridge type are given in Table4.2A. Applicability is determined by the “regularity” of abridge which is a function of the number of spans and thedistribution of weight and stiffness. Regular bridges haveless than seven spans, no abrupt or unusual changes inweight, stiffness, or geometry and no large changes inthese parameters from span-to-span or support-to-support(abutments excluded). They are defined in Table 4.2B.Any bridge not satisfying the requirements of Table 4.2B

is considered to be “not regular.” A more rigorous, gener-ally accepted analysis procedure may be used in lieu of therecommended minimum such as the Time HistoryMethod (Procedure 4).

Curved bridges comprised of multiple simple spansshall be considered to be “not regular” bridges if the sub-tended angle in plan is greater than 20º; such bridges shallbe analyzed by either Procedure 3 or 4.

4.2.1 Special Requirements for Single-Span Bridgesand Bridges in SPC A

Notwithstanding the above requirements, detailed seis-mic analysis is not required for a single-span bridge or forbridges classified as SPC A.

4.2.2 Special Requirements for Curved Bridges

A curved continuous-girder bridge may be analyzed asif it were straight provided all of the following require-ments are satisfied:

(a) the bridge is regular as defined in Table 4.2B ex-cept that for a two-span bridge the maximum spanlength ratio from span-to-span must not exceed 2;(b) the subtended angle in plan is not greater than 30°;and

TABLE 4.2A Minimum Analysis Requirements

TABLE 4.2B Regular Bridge Requirements


(c) the span lengths of the equivalent straight bridgeare equal to the arc lengths of the curved bridge.

If these requirements are not satisfied, then curved con-tinuous-girder bridges must be analyzed using the actualcurved geometry.

4.2.3 Special Requirements for Critical Bridges

More rigorous methods of analysis are required for cer-tain classes of important bridges which are considered tobe critical structures (e.g., those that are major structuresin size and cost or perform a critical function), and/or forthose that are geometrically complex and close to activeearthquake faults. Time history methods of analysis arerecommended for this purpose, provided care is takenwith both the modeling of the structure and the selectionof the input time histories of ground acceleration. Timehistory methods of analysis are described in Article 4.6.

4.3 UNIFORM LOAD METHOD—PROCEDURE 1

The uniform load method, described in the followingsteps, may be used for both transverse and longitudinalearthquake motions. It is essentially an equivalent staticmethod of analysis which uses a uniform lateral load toapproximate the effect of seismic loads. The method issuitable for regular bridges that respond principally intheir fundamental mode of vibration. Whereas all dis-placements and most member forces are calculated withgood accuracy, the method is known to overestimate thetransverse shears at the abutments by up to 100%. If suchconservatism is undesirable then the single mode spectralanalysis method (Procedure 2) is recommended.

Step 1. Calculate the static displacements vs(x) due toan assumed uniform load po as shown in Figure 4.4A andFigure 4.4B. The uniform loading po is applied over thelength of the bridge; it has units of force/unit length andmay be arbitrarily set equal to 1.0. The static displacementvs(x) has units of length.

Step 2. Calculate the bridge lateral stiffness, K, andtotal weight, W, from the following expressions:

where L � total length of the bridge

vs, MAX � maximum value of vs(x)

and w(x) � weight per unit length of the deadload of the bridge superstructure andtributary substructure

The weight should take into account structural ele-ments and other relevant loads including, but not limitedto, pier caps, abutments, columns and footings. Otherloads such as live loads may be included. (Generally, theinertia effects of live loads are not included in the analy-sis; however, the probability of a large live load being onthe bridge during an earthquake should be consideredwhen designing bridges with high live-to-dead load ratioswhich are located in metropolitan areas where traffic con-gestion is likely to occur.)

Step 3. Calculate the period of the bridge, T, usingthe expression:

where g � acceleration of gravity (length/time2)

Step 4. Calculate the equivalent static earthquakeloading pe from the expression:

where Cs � the dimensionless elastic seismic responsecoefficient given by Equation (3-1)

pe � equivalent uniform static seismic loadingper unit length of bridge applied to repre-sent the primary mode of vibration.

Step 5. Calculate the displacements and memberforces for use in design either by applying pe to the struc-ture and performing a second static analysis or by scalingthe results of Step 1 by the ratio pe/po.

4.4 SINGLE MODE SPECTRAL ANALYSISMETHOD—PROCEDURE 2

The single mode spectral analysis method described inthe following steps may be used for both transverse andlongitudinal earthquake motions. Examples illustrating itsapplication are given in the Commentary.

Step 1. Calculate the static displacements vs(x) due toan assumed uniform loading po as shown in Figure 4.4A.

pC W

Les= ( )4 - 4

TW

gK= 2 4 3π ( )-

W w x dx= ∫ ( ) ( )4 - 2

Kp L

vo

s MAX

=,

( )4 1-

454 HIGHWAY BRIDGES 4.2.2


The uniform loading po is applied over the length of thebridge; it has units of force/unit length and is arbitrarilyset equal to 1. The static displacement vs(x) has units oflength.

Step 2. Calculate factors �, �, and �:

where w(x) is the weight of the dead load of the bridge su-perstructure and tributary substructure (force/unit length).The computed factors, �, �, �, have units of (length2),(force � length), and (force � length2), respectively.

The weight should take into account structural ele-ments and other relevant loads including, but not limitedto, pier caps, abutments, columns and footings. Otherloads such as live loads may be included. (Generally, theinertia effects of live loads are not included in the analy-sis; however, the probability of a large live load being onthe bridge during an earthquake should be consideredwhen designing bridges with high live-to-dead load ratioswhich are located in metropolitan areas where traffic con-gestion is likely to occur.)

Step 3. Calculate the period of the bridge, T, usingthe expression:

where g � acceleration of gravity (length/time2).

Step 4. Calculate the equivalent static earthquakeloading pe(x) from the expression:

where,

Cs � the dimensionless elastic seismic response co-efficient given by Equation (3-1),

pe(x) � the intensity of the equivalent static seismicloading applied to represent the primary modeof vibration (force/unit length).

Step 5. Apply loading pe(x) to the structure as shownin Figure 4.4B and determine the resulting member forcesand displacements for design.

4.5 MULTIMODE SPECTRAL ANALYSISMETHOD—PROCEDURE 3

The multimode response spectrum analysis should beperformed with a suitable space frame linear dynamicanalysis computer program.

4.5.1 General

The multimode spectral analysis method applies tobridges with irregular geometry which induces couplingin the three coordinate directions within each mode ofvibration. These coupling effects make it difficult to cat-egorize the modes into simple longitudinal or transversemodes of vibration and, in addition, several modes of vi-bration will in general contribute to the total response ofthe structure. A computer program with space frame dy-namic analysis capabilities should be used to determinecoupling effects and multimodal contributions to thefinal response. Motions applied at the supports in anyone of the two horizontal directions will produce forcesalong both principal axes of the individual members be-cause of the coupling effects. For curved structures, thelongitudinal motion shall be directed along a chord con-necting the abutments and the transverse motion shall beapplied normal to the chord. Forces due to longitudinaland transverse motions shall be combined as specified inArticle 3.9.

p xC

w x v xes

s( ) ( ) ( ) ( )= βγ

4 9-

Tp go

= 2 4 8π γα

( )-

α

β

γ

=

=

=

∫∫∫

v x dx

w x v x dx

w x v x dx

s

s

s

( ) ( )

( ) ( ) ( )

( ) ( ) ( )

4 5

4 6

4 72

-

-

-

4.2.2 DIVISION IA—SEISMIC DESIGN 455

FIGURE 4.4A Bridge Deck Subjected to AssumedTransverse and Longitudinal Loading

FIGURE 4.4B Bridge Deck Subjected to EquivalentTransverse and Longitudinal Seismic Loading



4.5.2 Mathematical Model

The bridge should be modeled as a three-dimensionalspace frame with joints and nodes selected to realisticallymodel the stiffness and inertia effects of the structure.Each joint or node should have six degrees of freedom,three translational and three rotational. The structuralmass should be lumped with a minimum of three transla-tional inertia terms.

The mass should take into account structural elementsand other relevant loads including, but not limited to, piercaps, abutments, columns and footings. Other loads suchas live loads may be included. (Generally, the inertia ef-fects of live loads are not included in the analysis; how-ever, the probability of a large live load being on thebridge during an earthquake should be considered whendesigning bridges with high live-to-dead load ratios whichare located in metropolitan areas where traffic congestionis likely to occur.)

4.5.2(A) Superstructure

The superstructure should, as a minimum, be modeledas a series of space frame members with nodes at suchpoints as the span quarter points in addition to joints at theends of each span. Discontinuities should be included inthe superstructure at the expansion joints and abutments.Care should be taken to distribute properly the lumpedmass inertia effects at these locations. The effect of earth-quake restrainers at expansion joints may be approxi-mated by superimposing one or more linearly elasticmembers having the stiffness properties of the engaged re-strainer units.

4.5.2(B) Substructure

The intermediate columns or piers should also be mod-eled as space frame members. Generally, for short, stiffcolumns having lengths less than one-third of either of theadjacent span lengths, intermediate nodes are not neces-sary. Long, flexible columns should be modeled with in-termediate nodes at the third points in addition to thejoints at the ends of the columns. The model should con-sider the eccentricity of the columns with respect to thesuperstructure. Foundation conditions at the base of thecolumns and at the abutments may be modeled usingequivalent linear spring coefficients.

4.5.3 Mode Shapes and Periods

The required periods and mode shapes of the bridge inthe direction under consideration shall be calculated by

established methods for the fixed base condition using themass and elastic stiffness of the entire seismic resistingsystem.

4.5.4 Multimode Spectral Analysis

The response should, as a minimum, include the effectsof a number of modes equivalent to three times the num-ber of spans up to a maximum of 25 modes.

4.5.5 Combination of Mode Forces andDisplacements

The member forces and displacements can be esti-mated by combining the respective response quantities(e.g., force, displacement, or relative displacement)from the individual modes by the Complete QuadraticCombination (CQC) method. The member forces anddisplacements obtained using the CQC method of com-bining modes is generally adequate for most bridge systems.

4.6 TIME HISTORY METHOD—PROCEDURE 4

Any step-by-step, time history method of dynamicanalysis, that has been validated by experiment and/or comparative performance with similar methods, maybe used provided the following requirements are also satisfied:

(a) The time histories of input acceleration used to de-scribe the earthquake loads shall be selected in consul-tation with the Owner or Owner’s representative. Un-less otherwise directed, five spectrum-compatible timehistories shall be used when site-specific time historiesare not available. The spectrum used to generate thesefive time histories shall preferably be a site-specificspectrum. In the absence of such a spectrum, the re-sponse coefficient given by Equation (3-1), for the ap-propriate soil type, may be used to generate a spectrum.(b) The sensitivity of the numerical solution to the sizeof the time step used for the analysis shall be deter-mined. A sensitivity study shall also be carried out toinvestigate the effects of variations in assumed mate-rial properties.(c) If an in-elastic time history method of analysis isused, the R-factors permitted by Article 3.7 shall betaken as 1.0 for all substructures and connections.


457

Section 5DESIGN REQUIREMENTS FOR BRIDGES

IN SEISMIC PERFORMANCE CATEGORY A

5.1 GENERAL

Bridges classified as SPC A in accordance with Table3.4 of Article 3.4 shall conform to all the requirements ofthis Section.

5.2 DESIGN FORCES FOR SEISMICPERFORMANCE CATEGORY A

If a mechanical device is used to connect the super-structure to the substructure it shall be designed to resist ahorizontal seismic force in each restrained direction equalto 0.20 times the tributary weight.

For each segment of a superstructure, the tributaryweight at the line of fixed bearings, used to determine thelongitudinal connection design force, is defined as thetotal weight of the segment.

If each bearing supporting a segment or simply sup-ported span is restrained in the transverse direction, thetributary weight used to determine the transverse connec-tion design force is defined as the dead load reaction atthat bearing.

5.3 DESIGN DISPLACEMENTS FOR SEISMICPERFORMANCE CATEGORY A

Minimum bearing support lengths as determined inthis article shall be provided for the expansion ends of allgirders.

Bridges classified as SPC A shall meet the followingrequirement: Bearing seats supporting the expansion endsof girders, as shown in Figure 3.10, shall be designed toprovide a minimum support length N (in. or mm), mea-sured normal to the face of an abutment or pier, not lessthan that specified below.

N � (8 � 0.02L � 0.08H)

(1 � 0.000125S2) (in) (5-1A)

or,

N� (203 � 1.67L � 6.66H)

(1 � 0.000125S2) (mm) (5-1B)

where,

L � length, in feet for Equation (5-1A) or meters forEquation (5-1B), of the bridge deck to the adja-cent expansion joint, or to the end of the bridgedeck. For hinges within a span, L shall be the sumof L1 and L2, the distances to either side of thehinge. For single span bridges L equals the lengthof the bridge deck. These lengths are shown inFigure 3.10.

S � angle of skew of support in degrees, measuredfrom a line normal to the span.

and H is given by one of the following:

for abutments, H is the average height, in feet forEquation (5-1A) or meters for Equation (5-1B), ofcolumns supporting the bridge deck to the next ex-pansion joint. H � 0 for single span bridges.

for columns and/or piers, H is the column or pierheight in feet for Equation (5-1A) or meters forEquation (5-1B).

for hinges within a span, H is the average height of the adjacent two columns or piers in feet forEquation (5-1A) or meters for Equation (5-1B).

5.4 FOUNDATION AND ABUTMENT DESIGNREQUIREMENTS FOR SEISMICPERFORMANCE CATEGORY A

There are no special seismic design requirements for the foundations and abutments of bridges in this category.

Nevertheless, compliance is assumed with all require-ments that are necessary to provide support for vertical



and lateral loads other than those due to earthquake mo-tions. These include, but are not limited to, provisions forthe extent of foundation investigation, fills, slope stabil-ity, bearing and lateral soil pressures, drainage, settlementcontrol, and pile requirements and capacities.

5.5 STRUCTURAL STEEL DESIGNREQUIREMENTS FOR SEISMICPERFORMANCE CATEGORY A

No consideration of seismic forces is required for thedesign of structural components for bridges in this cate-gory except for the design of the connection of the super-structure to the substructure as specified in Article 5.2.

Nevertheless, design and construction of structuralsteel columns and connections shall conform to the re-quirements of Division I. Either Service Load or LoadFactor design may be used. If Service Load design is

used the allowable stresses are permitted to increase by50%.

5.6 REINFORCED CONCRETE DESIGNREQUIREMENTS FOR SEISMICPERFORMANCE CATEGORY A

No consideration of seismic forces is required for the design of structural components for bridges in thiscategory except for the design of the connection of the superstructure to the substructure as specified in Ar-ticle 5.2.

Nevertheless, design and construction of cast-in-placemonolithic reinforced concrete columns, pier footings andconnections shall conform to the requirements of DivisionI. Either Service Load or Load Factor design may be used.If Service Load design is used the allowable stresses arepermitted to increase by 331⁄ 3%.


459

Section 6DESIGN REQUIREMENTS FOR BRIDGES

IN SEISMIC PERFORMANCE CATEGORY B

6.1 GENERAL

Bridges classified as SPC B in accordance with Table3.4 of Article 3.4 shall conform to all the requirements ofthis section.

6.2 DESIGN FORCES FOR SEISMICPERFORMANCE CATEGORY B

6.2.1 Design Forces for Structural Members andConnections

Seismic design forces specified in this subsection shallapply to:

(a) The superstructure, its expansion joints and theconnections between the superstructure and the sup-porting substructure.(b) The supporting substructure down to the base ofthe columns and piers but not including the footing,pile cap, or piles.(c) Components connecting the superstructure to theabutment.

Seismic design forces for the above components shallbe determined by dividing the elastic seismic forces ob-tained from Load Case 1 and Load Case 2 of Article 3.9by the appropriate Response Modification Factor of Arti-cle 3.7. The modified seismic forces resulting from thetwo load cases shall then be combined independently withforces from other loads as specified in the following grouploading combination for the components. Note that theseismic forces are reversible (positive and negative) andthe maximum loading for each component shall be calcu-lated as follows:

Group Load � 1.0(D � B � SF � E � EQM) (6-1)

where,

D � dead loadB � buoyancy

SF � stream-flow pressureE � earth pressure

EQM � elastic seismic force for either Load Case 1 orLoad Case 2 of Article 3.9 modified by di-viding by the appropriate R-Factor.

Each component of the structure shall be designed towithstand the forces resulting from each load combinationaccording to Division I, and the additional requirementsof this section. Note that Equation (6-1) shall be used inlieu of the Division I, Group VII group loading combina-tion and that the � and � factors equal 1. For Service Loaddesign, a 50% increase is permitted in the allowablestresses for structural steel and a 331⁄ 3% increase for rein-forced concrete.

6.2.2 Design Forces for Foundations

Seismic design forces for foundations, including foot-ings, pile caps, and piles shall be the elastic seismic forcesobtained from Load Case 1 and Load Case 2 of Article 3.9divided by the Response Modification Factor (R) from Ar-ticle 3.7 and modified as specified below. These modifiedseismic forces shall then be combined independently withforces from other loads as specified in the following grouploading combination to determine two alternate loadcombinations for the foundations.

Group Load � 1.0(D � B � SF � E � EQF) (6-2)

where D, B, E, and SF are as defined in Article 6.2.1, and

EQF � the elastic seismic force for either Load Case1 or Load Case 2 of Article 3.9 divided byone-half of the Response Modification Factorfor the substructure (column or pier) to whichthe foundation is attached.

EXCEPTION:For pile bents, the Response Modification Factor shallnot be reduced by one-half.


If a Group Load other than Equation (6-1) governs thedesign of the columns, seismic forces transferred to thefoundations may be larger than those calculated usingEquation (6-2), due to possible overstrength of columns.

Each component of the foundation shall be designed toresist the forces resulting from each load combination ac-cording to the requirements of Division I and to the addi-tional requirements of Article 6.4.

6.2.3 Design Forces for Abutments and RetainingWalls

The components connecting the superstructure to anabutment (e.g., bearings and shear keys) shall be designedto resist the forces specified in Article 6.2.1.

Design requirements for abutments are given in Arti-cle 6.4.3.

6.3 DESIGN DISPLACEMENTS FOR SEISMICPERFORMANCE CATEGORY B

The seismic design displacements shall be the maxi-mum of those determined in accordance with Article 3.8or those specified in Article 6.3.1.

6.3.1 Minimum Support Length Requirements forSeismic Performance Category B

Bridges classified as SPC B shall meet the followingrequirement: Bearing seats supporting the expansion endsof girders, as shown in Figure 3.10, shall be designed toprovide a minimum support length N (in. or mm) mea-sured normal to the face of an abutment or pier, not lessthan that specified below.

N� (8 � 0.02L � 0.08H)

(1 � 0.000125S2) (in.) (6-3A)

or,

N� (203 � 1.67L � 6.66H)

(1 � 0.000125S2) (mm) (6-3B)

where,

L � length, in feet for Equation (6-3A) or meters forEquation (6-3B), of the bridge deck to the adja-cent expansion joint, or to the end of the bridgedeck. For hinges within a span, L shall be the sumof L1 and L2, the distances to either side of thehinge. For single span bridges L equals the lengthof the bridge deck. These lengths are shown inFigure 3.10.

S � angle of skew of support in degrees, measuredfrom a line normal to the span.




for hinges within a span, H is the average height ofthe adjacent two columns or piers in feet for Equa-tion (6-3A) or meters for Equation (6-3B).

6.4 FOUNDATION AND ABUTMENT DESIGNREQUIREMENTS FOR SEISMICPERFORMANCE CATEGORY B

6.4.1 General

This section includes only those foundation and abut-ment requirements that are specifically related to seismicresistant construction in SPC B. It assumes compliancewith all requirements that are necessary to provide sup-port for vertical and lateral loads other than those due toearthquake motions. These include, but are not limited to,provisions for the extent of foundation investigation,fills, slope stability, bearing and lateral soil pressures,drainage, settlement control, and pile requirements andcapacities.

Foundation and abutment seismic design requirementsfor SPC B are given in the following subarticles.

6.4.2 Foundations

6.4.2(A) Investigation

In addition to the normal site investigation report, theEngineer may require the submission of a report whichdescribes the results of an investigation to determine po-tential hazards and seismic design requirements related to(1) slope instability, (2) liquefaction, (3) fill settlement,and (4) increases in lateral earth pressure, all as a result ofearthquake motions. Seismically induced slope instabilityin approach fills or cuts may displace abutments and leadto significant differential settlement and structural dam-age. Fill settlement and abutment displacements due tolateral pressure increases may lead to bridge access prob-lems and structural damage. Liquefaction of saturated co-hesionless fills or foundation soils may contribute to slopeand abutment instability, and could lead to a loss of foun-dation-bearing capacity and lateral pile support. Lique-



faction failures of the above type have led to bridge fail-ures during past earthquakes.

6.4.2(B) Foundation Design

For the load combinations specified in Article 6.2.2,the soil strength capable of being mobilized by the foun-dations shall be established in the site investigation report.Because of the dynamic cyclic nature of seismic loading,the ultimate capacity of the foundation supportingmedium should be used in conjunction with these loadcombinations. Due consideration shall be given to themagnitude of the seismically induced foundation settle-ment that the bridge can withstand.

Transient foundation uplift or rocking involving sepa-ration from the subsoil of up to one-half of an end bearingfoundation pile group or up to one-half of the contact areaof foundation footings is permitted under seismic loading,provided that foundation soils are not susceptible to lossof strength under the imposed cyclic loading.

General comments on soil strength and stiffness mobi-lized during earthquakes, foundation uplift, lateral load-ing of piles, soil-structure interaction and foundation de-sign in environments susceptible to liquefaction areprovided in the Commentary.

6.4.2(C) Special Pile Requirements

The following special pile requirements are in additionto the requirements for piles in other applicable specifica-tions.

Piles may be used to resist both axial and lateral loads.The minimum depth of embedment, together with theaxial and lateral pile capacities, required to resist seismicloads shall be determined by means of the design criteriaestablished in the site investigation report. Note that theultimate capacity of the piles should be used in designingfor seismic loads.

All piles shall be adequately anchored to the pile foot-ing or cap. Concrete piles shall be anchored by embed-ment of sufficient length of pile reinforcement (unlessspecial anchorage is provided) to develop uplift forces butin no case shall this length be less than the developmentlength required for the reinforcement. Each concrete-filled pipe pile shall be anchored by at least four reinforc-ing steel dowels with a minimum steel ratio of 0.01 em-bedded sufficiently as required for concrete piles. Timberand steel piles, including unfilled pipe piles, shall be pro-vided with anchoring devices to develop all uplift forcesadequately but in no case shall these forces be less than10% of the allowable pile load.

All concrete piles shall be reinforced to resist the de-sign moments, shears, and axial loads. Minimum rein-forcement shall be not less than the following:

1. Cast-in-Place Concrete Piles. Longitudinal rein-forcing steel shall be provided for cast-in-place concretepiles in the upper one-third (8 feet or 2.4 metersminimum) of the pile length with a minimum steel ratioof 0.005 provided by at least four bars. Spiral reinforce-ment or equivalent ties of 1⁄4 inches (6 millimeters) diameter or larger shall be provided at 9 inches (225 mil-limeters) maximum pitch, except for the top 2 feet (610millimeters) below the pile cap reinforcement where thepitch shall be 3 inches (75 millimeters) maximum.2. Precast Piles. Longitudinal reinforcing steel shallbe provided for each precast concrete pile with a min-imum steel ratio of 0.01 provided by at least four bars.Spiral reinforcement or equivalent ties of No. 3 bars orlarger shall be provided at 9 inches (225 millimeters)maximum pitch, except for the top 2 feet (610 mil-limeters) below the pile cap reinforcement where thepitch shall be 3 inches (75 millimeters) maximum.3. Precast-Prestressed Piles. Ties in precast-pre-stressed piles shall conform to the requirements of pre-cast piles.

6.4.3 Abutments

6.4.3(A) Free-Standing Abutments

For free-standing abutments or retaining walls whichmay displace horizontally without significant restraint(e.g., superstructure supported by sliding bearings), thepseudostatic Mononobe-Okabe method of analysis is recommended for computing lateral active soil pressuresduring seismic loading. A seismic coefficient equal toone-half the acceleration coefficient (kh � 0.5A) is recommended. The effects of vertical acceleration may beomitted. Abutments should be proportioned to slide ratherthan tilt, and provisions should be made to accommodatesmall horizontal seismically induced abutment displace-ments when minimal damage is desired at abutment sup-ports. Abutment displacements of up to 10A inches (250Amillimeters) may be expected.

The seismic design of free-standing abutments shouldtake into account forces arising from seismically inducedlateral earth pressures, additional forces arising from wallinertia effects and the transfer of seismic forces from thebridge deck through bearing supports which do not slidefreely (e.g., elastomeric bearings).

For free-standing abutments which are restrained from horizontal displacement by anchors or batter piles,the magnitudes of seismically induced lateral earth pres-sures are higher than those given by the Mononobe-Okabe method of analysis. As a first approximation, it is recommended that the maximum lateral earth pressurebe computed by using a seismic coefficient kh � 1.5A inconjunction with the Mononobe-Okabe analysis method.

6.4.2(A) DIVISION IA—SEISMIC DESIGN 461


6.4.3(B) Monolithic Abutments

For monolithic abutments where the abutment formsan integral part of the bridge superstructure, maximumearth pressures acting on the abutment may be assumedequal to the maximum longitudinal earthquake forcetransferred from the superstructure to the abutment. Tominimize abutment damage, the abutment should be de-signed to resist the passive pressure capable of being mo-bilized by the abutment backfill, which should be greaterthan the maximum estimated longitudinal earthquakeforce transferred to the abutment. It may be assumed thatthe lateral active earth pressure during seismic loading isless than the superstructure earthquake load.

When longitudinal seismic forces are also resisted by piers or columns, it is necessary to estimate abut-ment stiffness in the longitudinal direction in order tocompute the proportion of earthquake load transferred tothe abutment.

6.5 STRUCTURAL STEEL DESIGNREQUIREMENTS FOR SEISMICPERFORMANCE CATEGORY B

6.5.1 General

Design and construction of structural steel columnsand connections shall conform to the requirements of Di-vision I and to the additional requirements of this section.Either Service Load or Load Factor design may be used.If Service Load design is used the allowable stresses arepermitted to increase by 50%.

6.5.2 P-delta Effects

Where axial and flexural stresses are determined byconsidering secondary bending resulting from the designP-delta effects (moments induced by the eccentricity re-sulting from the seismic displacements and the columnaxial force), all axially loaded members may be propor-tioned in accordance with Division I, Article 10.36 or10.54.

EXCEPTIONS:

1. The effective length factor, K, in the plane of bend-ing may be assumed to be unity in the calculation of Fa,Fe�, Fcr, or Fe.2. The coefficient Cm is computed as for the caseswhere joint translation is prevented.

6.6 REINFORCED CONCRETE DESIGNREQUIREMENTS FOR SEISMICPERFORMANCE CATEGORY B

6.6.1 General

Design and construction of cast-in-place monolithicreinforced concrete columns, pier footings and connec-tions shall conform to the requirements of Division I andto the additional requirements of this section. Either Ser-vice Load or Load Factor design may be used. If ServiceLoad design is used the allowable stresses are permittedto increase by 331⁄ 3%.

6.6.2 Minimum Transverse ReinforcementRequirements for Seismic PerformanceCategory B

For bridges classified as SPC B, the minimum trans-verse reinforcement requirements at the top and bottom ofa column shall be as required in Article 6.6.2(A). Thespacing of the transverse reinforcement shall be as re-quired in Article 6.6.2(B).

6.6.2(A) Transverse Reinforcement for Confinement

The cores of columns, pile bents, and drilled shafts shallbe confined by transverse reinforcement in the expectedplastic hinge regions, generally located at the top and bot-tom of columns and pile bents, as specified in this sub-section. The transverse reinforcement for confinementshall have a yield strength not more than that of the lon-gitudinal reinforcement and the spacing shall be as speci-fied in Article 6.6.2(B).

The volumetric ratio of spiral reinforcement (�s) for acircular column shall be either that required in Division I,Article 8.18 or,

or,

whichever is greater.The total gross sectional area (Ash) of rectangular hoop

(stirrup) reinforcement for a rectangular column shall beeither,

ρsc

yh

f

f= ′

0 12 6. ( - 5)

ρsg

c

c

yh

A

A

f

f= −

′ −0 45 1 6 4. ( )

462 HIGHWAY BRIDGES 6.4.3(B)



or,

whichever is greater, where:

a � vertical spacing of hoops (stirrups) in inches(millimeters) with a maximum of 6 inches (150millimeters)

Ac � area of column core measured to the outside ofthe transverse spiral reinforcement

Ag � gross area of columnAsh � total cross-sectional area in square inches

(square millimeters) of hoop (stirrup) reinforce-ment including supplementary cross ties havinga vertical spacing of an inch (millimeter) andcrossing a section having a core dimension of hc

inches (millimeters). Note that this should becalculated for both principal axes of a rectangu-lar column.

fc� � specified compressive strength of concrete inpsi (MPa)

fyh � yield strength of hoop or spiral reinforcement inpsi (MPa)

hc � core dimension of tied column in inches (mil-limeters) in the direction under consideration

�s � ratio of volume of spiral reinforcement to totalvolume of concrete core (out-to-out of spirals).

Transverse hoop reinforcement may be provided bysingle or overlapping hoops. Cross-ties having the samebar size as the hoop may be used. Each end of the cross-tie shall engage a peripheral longitudinal reinforcing bar.

A crosstie is a continuous bar having a hook of not lessthan 135° with an extension of not less than six-diameter,but not less than 3 inches (76 millimeters), at one end anda hook of not less than 90° with an extension of not lessthan six-diameter at the other end. The hooks shall engage

peripheral longitudinal bars. The 90° hooks of two suc-cessive crossties engaging the same longitudinal barsshall be alternated end for end.

A hoop is a closed tie or continuously wound tie. Aclosed tie may be made up of several reinforcing elementswith 135° hooks having a six-diameter, but not less than3 inches (76 millimeters), extension at each end. A con-tinuously wound tie shall have at each end a 135° hookwith a six-diameter, but not less than 3 inches (76 milli-meters), extension that engages the longitudinal rein-forcement.

6.6.2(B) Spacing of Transverse Reinforcement for Confinement

1. Transverse reinforcement for confinement shall be provided at the top and bottom of the column over a length equal to the maximum cross-sectionalcolumn dimension or one-sixth of the clear height of the column whichever is the larger but not less than18 inches (450 millimeters). Transverse reinforcementshall be extended into the top and bottom connectionsfor a distance equal to one-half the maximum columndimension but not less than 15 inches (375 millime-ters) from the face of the column connection into theadjoining member.2. Transverse reinforcement for confinement shall beprovided at the top of piles in pile bents over the samelength as specified for columns. At the bottom of pilesin pile bents, transverse reinforcement for confinementshall be provided over a length extending from threepile diameters below the calculated point of momentfixity to one pile diameter but not less than 18 inches(450 millimeters) above the mud line.3. The maximum spacing for reinforcement shall notexceed the smaller of one-quarter of the minimummember dimension or 6 inches (150 millimeters).4. Lapping of spiral reinforcement in the transverseconfinement regions specified in 1 and 2 shall not bepermitted. Connections of spiral reinforcement in thisregion must be full strength lap welds.

A ahf

fsh cc

yh

= ′0 12. (6 - 7)

A ahf

f

A

Ash cc

yh

g

c

= ′ −

0 30 1 6. ( - 6)


Section 7DESIGN REQUIREMENTS FOR BRIDGES IN SEISMIC

PERFORMANCE CATEGORIES C AND D

7.1 GENERAL

Bridges classified as either SPC C or SPC D in accor-dance with Table 1 of Article 3.4 shall conform to all therequirements of this Section.

7.2 DESIGN FORCES FOR SEISMICPERFORMANCE CATEGORIES C AND D

Two sets of design forces are specified in Articles 7.2.1and 7.2.2 for bridges classified as Category C or D. Thedesign forces for the various components are specified inArticles 7.2.3 through 7.2.7.

7.2.1 Modified Design Forces

Design forces shall be determined as in Articles7.2.1(A) and 7.2.1(B). Note that for columns a maximumand minimum axial force shall be calculated for each load case by taking the seismic axial force as positive andnegative.

7.2.1(A) Modified Design Forces for StructuralMembers and Connections

Seismic design forces specified in this Article shallapply to:

(a) The superstructure, its expansion joints and theconnections between the superstructure and the sup-porting substructure.(b) The supporting substructure down to the base ofthe columns and piers but not including the footing,pile cap, or piles.(c) Components connecting the superstructure to theabutment.

Seismic design forces for the above components shallbe determined by dividing the elastic seismic forces ob-tained from Load Case 1 and Load Case 2 of Article 3.9by the appropriate Response Modification Factor of Arti-

cle 3.7. The modified seismic forces resulting from thetwo load cases shall then be combined independently withforces from other loads as specified in the following grouploading combination for the components. Note that theseismic forces are reversible (positive and negative) andthe maximum loading for each component shall be calcu-lated as follows:

Group Load � 1.0(D � B � SF � E � EQM) (7-1)

where,

D � dead loadB � buoyancy

SF � stream-flow pressureE � earth pressure

EQM � elastic seismic force for either Load Case 1 or Load Case 2 of Article 3.9 modified by dividing by the appropriate R-Factor.

Each component of the structure shall be designed towithstand the forces resulting from each load combinationaccording to Division I, and the additional requirementsof this chapter. Note that Equation (7-1) shall be used inlieu of the Division I, Group VII group loading combina-tion and that the � and � factors equal 1. For Service LoadDesign, a 50% increase is permitted in the allowablestresses for structural steel and a 331⁄ 3% increase for rein-forced concrete.

7.2.1(B) Modified Design Forces for Foundations

Seismic design forces for foundations, including foot-ings, pile caps, and piles shall be the elastic seismic forcesobtained from Load Case 1 and Load Case 2 of Article 3.9divided by the Response Modification Factor (R) speci-fied below. These modified seismic forces shall then becombined independently with forces from other loads as specified in the following group loading combinationto determine two alternate load combinations for the foundations.

465


Group Load � 1.0(D � B � SF � E � EQF) (7-2)

where D, B, E, and SF are as defined in Article 7.2.1 and

EQF � the elastic seismic force for either Load Case 1or Load Case 2 of Article 3.9 divided by an R-Factor equal to 1.0.

Each component of the foundation shall be designed to resist the forces resulting from each load combinationaccording to the requirements of Division I and to the additional requirements of Article 7.2.6.

7.2.2 Forces Resulting from Plastic Hinging in theColumns, Piers, or Bents

The force resulting from plastic hinging at the topand/or bottom of the column shall be calculated after thepreliminary design of the columns is complete. The forcesresulting from plastic hinging are recommended for de-termining design forces for most components as specifiedin Articles 7.2.3 through 7.2.6. Alternate conservative de-sign forces are specified if forces resulting from plastichinging are not calculated. The procedures for calculatingthese forces for single column and pier supports and bentswith two or more columns are given in the following subsections.

7.2.2(A) Single Columns and Piers

The forces shall be calculated for the two principalaxes of a column and in the weak direction of a pier orbent as follows:

Step 1. Determine the column overstrength plasticmoment capacities. For reinforced concrete columns, usea strength reduction factor (�) of 1.3 and for structuralsteel columns use 1.25 times the nominal yield strength.(Note: This corresponds to the normal use of a strengthreduction factor for reinforced concrete. In this case it pro-vides an increase in the ultimate strength.) For both mate-rials use the maximum elastic column axial load from Article 3.9 added to the column dead load.

Step 2. Using the column overstrength plastic mo-ments, calculate the corresponding column shear force.For flared columns this calculation shall be performedusing the overstrength plastic moments at both the top andbottom of the flare with the appropriate column height. Ifthe foundation of a column is significantly below groundlevel, consideration should be given to the possibility ofthe plastic hinge forming above the foundation. If this canoccur the column length between plastic hinges shall beused to calculate the column shear force.

The forces corresponding to a single column hingingare:

(a) Axial Forces—unreduced maximum and mini-mum seismic axial load of Article 3.9 plus the deadload.(b) Moments—as calculated in Step 1.(c) Shear Force—as calculated in Step 2.

7.2.2(B) Bents with Two or More Columns

The forces for bents with two or more columns shall becalculated both in the plane of the bent and perpendicularto the plane of the bent. Perpendicular to the plane of thebent the forces shall be calculated as for single columns inaccordance with Article 7.2.2(A). In the plane of the bentthe forces shall be calculated as follows:

Step 1. Determine the column overstrength plasticmoment capacities. For reinforced concrete use a strengthreduction factor (�) of 1.3 and for structural steel use 1.25times the nominal yield strength. (Note: This correspondsto the normal use of a strength reduction factor for rein-forced concrete. In this case it provides an increase in theultimate strength.) For both materials use the axial loadcorresponding to the dead load.

Step 2. Using the column overstrength plastic mo-ments calculate the corresponding column shear forces.Sum the column shears of the bent to determine the max-imum shear force for the bent. Note that, if a partial-heightwall exists between the columns, the effective columnheight is taken from the top of the wall. For flared columnsand foundations below ground level, see Article 7.2.2(A)Step 2. For pile bents the length of pile above the mud lineshall be used to calculate the shear force.

Step 3. Apply the bent shear force to the top of thebent (center of mass of the superstructure above the bent)and determine the axial forces in the columns due to over-turning when the column overstrength plastic momentsare developed.

Step 4. Using these column axial forces combinedwith the dead load axial forces, determine revised columnoverstrength plastic moments. With the revised over-strength plastic moments calculate the column shearforces and the maximum shear force for the bent. If themaximum shear force for the bent is not within 10% of thevalue previously determined, use this maximum bentshear force and return to Step 3.

The forces in the individual columns in the plane of abent corresponding to column hinging, are:



(a) Axial Forces—the maximum and minimum axialload is the dead load plus, or minus, the axial load de-termined from the final iteration of Step 3.(b) Moments—the column overstrength plastic mo-ments corresponding to the maximum compressiveaxial load specified in (a) above, with a strength re-duction factor of 1.3 for reinforced concrete and 1.25times the nominal yield strength for structural steel.(c) Shear Force—the shear force corresponding to thecolumn overstrength moments in (b) above, noting theprovisions in Step 2 above.

7.2.3 Column and Pile Bent Design Forces

Design forces for columns and pile bents shall be thefollowing:

(a) Axial Forces—the minimum and maximum designforce shall either be the elastic design values deter-mined in Article 3.9 added to the dead load, or the val-ues corresponding to plastic hinging of the column anddetermined in Article 7.2.2. Generally, the values cor-responding to column hinging will be smaller.(b) Moments—the modified design moments deter-mined in Article 7.2.1.(c) Shear Force—either the elastic design value deter-mined from Article 7.2.1 using an R-Factor of 1 for thecolumn or the value corresponding to plastic hingingof the column as determined in Article 7.2.2. Gener-ally, the value corresponding to column hinging will besignificantly smaller.

7.2.4 Pier Design Forces

The design forces shall be those determined in Arti-cle 7.2.1 except if the pier is designed as a column in itsweak direction. If the pier is designed as a column thedesign forces in the weak direction shall be as specifiedin Article 7.2.3 and all the design requirements forcolumns of Article 7.6 shall apply. (Note: When theforces due to plastic hinging are used in the weak direc-tion the combination of forces specified in Article 3.9 isnot applicable.)

7.2.5 Connection Design Forces

The design forces shall be those determined in Article7.2.1 except that for superstructure connections tocolumns and column connections to cap beams or foot-ings, the alternate forces specified in 7.2.5(C) below arerecommended. Additional design forces at connectionsare as follows:

7.2.5(A) Longitudinal Linkage Forces

Positive horizontal linkage shall be provided betweenadjacent sections of the superstructure at supports and ex-pansion joints within a span. The linkage shall be de-signed for a minimum force of the Acceleration Coeffi-cient times the weight of the lighter of the two adjoiningspans or parts of the structure. If the linkage is at a pointwhere relative displacement of the sections of super-structure is designed to occur during seismic motions, suf-ficient slack must be allowed in the linkage so that thelinkage force does not start to act until the design dis-placement is exceeded. Where linkage is to be provided atcolumns or piers, the linkage of each span may be at-tached to the column or pier rather than between adjacentspans. Positive linkage shall be provided by ties, cables,dampers, or an equivalent mechanism. Friction shall notbe considered a positive linkage.

7.2.5(B) Hold-Down Devices

Hold-down devices shall be provided at all supports orhinges in continuous structures, where the vertical seismicforce due to the longitudinal horizontal seismic load op-poses and exceeds 50% but is less than 100% of the deadload reaction. In this case, the minimum net upward forcefor the hold-down device shall be 10% of the dead loaddownward force that would be exerted if the span weresimply supported.

If the vertical seismic force (Q) due to the longitudinalhorizontal seismic load opposes and exceeds 100 percentof the dead load reaction (DR), the net upwards force forthe hold-down device shall be 1.2(Q � DR) but it shallnot be less than that specified in the previous paragraph.

7.2.5(C) Column and Pier Connections to CapBeams and Footings

The recommended connection design forces betweenthe superstructure and columns, columns and cap beams,and columns and spread footings or pile caps are theforces developed at the top and bottom of the columns dueto column hinging and determined in Article 7.2.2. Thesmaller of these or the values specified in Article 7.2.1may be used. Note that these forces should be calculatedafter the column design is complete and the overstrengthmoment capacities have been obtained.

7.2.6 Foundation Design Forces

The design forces for foundations including footings,pile caps, and piles may be either those forces determinedin Article 7.2.1(B) or the forces at the bottom of thecolumns corresponding to column plastic hinging as

7.2.2(B) DIVISION IA—SEISMIC DESIGN 467


determined in Article 7.2.2. Generally, the values corre-sponding to column hinging will be significantly smaller.

When the columns of a bent have a common footingthe final force distribution at the base of the columns fromStep 4 of Article 7.2.2(B) may be used for the design ofthe footing in the plane of the bent. This force distributionproduces lower shear forces and moments on the footingbecause one exterior column may be in tension and theother in compression due to the seismic overturning mo-ment. This effectively increases the ultimate moments andshear forces on one column and reduces them on the other.

7.2.7 Abutment and Retaining Wall Design Forces

The components connecting the superstructure to anabutment (e.g., bearings and shear keys) shall be designedto resist the forces specified in Article 7.2.1.

Design requirements for abutments are given in Arti-cle 7.4.3 for SPC C and Article 7.4.5 for SPC D.

7.3 DESIGN DISPLACEMENT FOR SEISMICPERFORMANCE CATEGORIES C AND D

The seismic design displacements shall be the maxi-mum of those determined in accordance with Article 3.8or those specified in Article 7.3.1.

7.3.1 Minimum Support Length Requirements forSeismic Performance Categories C and D

Bridges classified as SPC C or D shall meet the fol-lowing requirement: Bearing seats supporting the expan-sion ends of girders, as shown in Figure 3.10, shall be de-signed to provide a minimum support length N (in. ormm), measured normal to the face of an abutment or pier,not less than that specified below.

N � (12 � 0.03L � 0.12H)(1 � 0.000125S2) (in.) (7-3A)

or,

N � (305 � 2.5L � 10H)(1 � 0.000125S2) (mm) (7-3B)

where,

L � length, in feet for Equation (7-3A) or meters forEquation (7-3B), of the bridge deck to the adjacentexpansion joint, or to the end of the bridge deck.For hinges within a span, L shall be the sum of L1

and L2, the distances to either side of the hinge. Forsingle span bridges Lequals the length of the bridgedeck. These lengths are shown in Figure 3.10.

S � angle of skew of support in degrees measuredfrom a line normal to the span.




for hinges within a span, H is the average height ofthe adjacent two columns or piers in feet for Equa-tion (7-3A) or meters for Equation (7-3B).

Positive horizontal linkages shall be provided at all su-perstructure expansion joints, including those jointswithin a span, as specified in Article 7.2.5.

Relative displacements between different segments ofthe bridge should be carefully considered in the evalua-tion of the results determined in accordance with Article3.8. Relative displacements arise from effects that are noteasily included in the analysis procedure but should beconsidered in determining the design displacements. Theyinclude the following:

(a) Torsional displacements of bridge decks onskewed supports.(b) Rotation and/or lateral displacements of the foun-dations.(c) Out-of-phase displacements of different segmentsof the bridge. This is especially important in determin-ing seat widths at expansion joints.(d) Out-of-phase rotation of abutments and columnsinduced by traveling seismic waves.

7.4 FOUNDATION AND ABUTMENT DESIGNREQUIREMENTS FOR SEISMICPERFORMANCE CATEGORIES C AND D

7.4.1 General

This section includes only those foundation and abut-ment requirements that are specifically related to seismicresistant construction in SPC C and D. It assumes com-pliance with all requirements that are necessary to providesupport for vertical and lateral loads other than those dueto earthquake motions. These include, but are not limitedto, provisions for the extent of foundation investigation,fills, slope stability, bearing and lateral soil pressures,drainage, settlement control, and pile requirements andcapacities.



Foundation and abutment seismic design requirementsfor SPC C are given in Articles 7.4.2 and 7.4.3. Require-ments for bridges in SPC D are given in Articles 7.4.4 and 7.4.5.

7.4.2 Foundation Requirements for SeismicPerformance Category C

Foundation and abutment seismic design requirementsfor SPC C are given in the following subsections.


In addition to the normal site investigation report, theEngineer may require the submission of a report whichdescribes the results of an investigation to determine po-tential hazards and seismic design requirements related to(1) slope instability, (2) liquefaction, (3) fill settlement,and (4) increases in lateral earth pressure, all as a result ofearthquake motions. Seismically induced slope instabilityin approach fills or cuts may displace abutments and leadto significant differential settlement and structural dam-age. Fill settlement and abutment displacements due tolateral pressure increases may lead to bridge access prob-lems and structural damage. Liquefaction of saturated co-hesionless fills or foundation soils may contribute to slopeand abutment instability, and could lead to a loss of foun-dation bearing capacity and lateral pile support. Lique-faction failures of the above type have led to bridge fail-ures during past earthquakes.

Further, the above report should include a determina-tion of the potential for surface rupture due to faulting ordifferential ground displacement (lurching), as a result ofearthquake motions.


The design forces for the foundations shall be thosespecified in Article 7.2.6.

The soil strength capable of being mobilized by thefoundations shall be established in the site investigationreport. Because of the dynamic cyclic nature of seismicloading, the ultimate capacity of the foundation support-ing medium should be used in conjunction with these loadcombinations. Due consideration shall be given to themagnitude of the seismically induced foundation settle-ment that the bridge can withstand.

Transient foundation uplift or rocking involving sepa-ration from the subsoil of up to one-half of an end bearingfoundation pile group or up to one-half of the contact areaof foundation footings is permitted under seismic loading,provided that foundation soils are not susceptible to lossof strength under the imposed cyclic loading.

For saturated sand and soft clay foundation soils, dueconsideration shall be given to the potential for soilstrength loss under the imposed cyclic loading in assess-ing the ultimate capacity of foundations.

General comments on soil strength and stiffness mobi-lized during earthquakes, foundation uplift, lateral load-ing of piles, soil-structure interaction and foundation de-sign in environments susceptible to liquefaction areprovided in the Commentary.

7.4.2(C) Special Pile Requirements

The following special pile requirements are in additionto the requirements for piles in other applicable specifica-tions.

Piles may be used to resist both axial and lateral loads.The minimum depth of embedment, together with theaxial and lateral pile capacities, required to resist seismicloads shall be determined by means of the design criteriaestablished in the site investigation report. Note that theultimate capacity of the piles should be used in designingfor seismic loads.

All piles shall be adequately anchored to the pile foot-ing or cap. Concrete piles shall be anchored by embed-ment of sufficient length of pile reinforcement (unlessspecial anchorage is provided) to develop uplift forces butin no case shall this length be less than the developmentlength required for the reinforcement. Each concrete-filled pipe pile shall be anchored by at least four reinforc-ing steel dowels with a minimum steel ratio of 0.01 em-bedded sufficiently as required for concrete piles. Timberand steel piles, including unfilled pipe piles, shall be pro-vided with anchoring devices to develop all uplift forcesadequately but in no case shall these forces be less than 10% of the allowable pile load.

All concrete piles shall be reinforced to resist the de-sign moments, shears, and axial loads.

The following special requirements for concrete pilesshall apply:

1. Anchorage. The longitudinal reinforcement of allconcrete piles shall be anchored to the pile footing orcap to develop a force of at least 1.25Asfy where As isthe area of longitudinal reinforcement in the concretepile and fy is its nominal yield strength.2. Confinement Length. The upper end of every pileshall be reinforced as a potential plastic hinge region,except where it can be established that there is no pos-sibility of any significant lateral deflections in the pileresulting from deformation. The potential plastic hingeregion shall, as a minimum, be considered to extendfrom the underside of the pile cap over a length of notless than two pile diameters or 24 inches (610 mil-

7.4.1 DIVISION IA—SEISMIC DESIGN 469


limeters). If an analysis of the bridge and pile systemindicates that a plastic hinge can form at a lower level,the transverse reinforcement requirements of (3) shallextend to that level. Note the special requirements forpile bents given in Article 7.6.2(C), (D), and (E).3. Volumetric Ratio for Confinement. The volumetricratio of transverse reinforcement to the distance speci-fied in (2) shall be as required for columns in Article7.6.2(D).4. Cast-in-Place Concrete Piles. Longitudinal steelshall be provided for cast-in-place concrete piles forthe full length of the pile. The upper two-thirds of thepile shall have a minimum longitudinal steel ratio of0.0075 provided by at least four bars. Spiral reinforce-ment or equivalent ties of 1⁄ 4 inch (6 millimeters) di-ameter or larger shall be provided at 9 inches (225 mil-limeters) maximum pitch, except for the top 4 feet (1.2meters) where the pitch shall be 3 inches (75 millime-ters maximum, and where the volumetric ratio shallconform to Article 7.6.2(D).5. Precast Concrete Piles. Longitudinal reinforcingsteel shall be provided for each precast concrete pilewith a minimum steel ratio of 0.01 provided by at leastfour bars. Spiral reinforcement ties in precast, includ-ing prestressed, concrete piles shall be No. 3 bars orlarger and shall be provided at 9 inches (225 millime-ters) maximum pitch except for the top 4 feet (1.2 me-ters) where the pitch shall be 3 inches (75 millimeters)and the volumetric ratio shall conform to 7.6.2(D).6. Precast-Prestressed Piles. Ties in precast-prestressedpiles shall conform to the requirements of precast piles.

7.4.3 Abutment Requirements for SeismicPerformance Category C

In addition to the provisions outlined in this section,consideration should be given to the mechanism of trans-fer of superstructure transverse inertial forces to thebridge abutments. Adequate resistance to lateral pressureshould be provided by wing walls or abutment keys tominimize lateral abutment displacements.

7.4.3(A) Free-Standing Abutments

For free-standing abutments or retaining walls whichmay displace horizontally without significant restraint(e.g., superstructure supported by sliding bearings), thepseudo-static Mononobe-Okabe method of analysis isrecommended for computing lateral active soil pressuresduring seismic loading. A seismic coefficient equal toone-half the acceleration coefficient (kh � 0.5A) is rec-ommended. The effects of vertical acceleration may beomitted. Abutments should be proportioned to slide rather

than tilt, and provisions should be made to accommodatesmall horizontal seismically induced abutment displace-ments when minimal damage is desired at abutment sup-ports. Abutment displacements of up to 10A inches (250Amillimeters) may be expected.

The seismic design of free-standing abutments shouldtake into account forces arising from seismically inducedlateral earth pressures, additional forces arising from wallinertia effects and the transfer of seismic forces from thebridge deck through bearing supports which do not slidefreely (e.g., elastomeric bearings).

For free-standing abutments which are restrained fromhorizontal displacement by anchors or batter piles, themagnitudes of seismically induced lateral earth pressuresare higher than those given by the Mononobe-Okabemethod of analysis. As a first approximation, it is recom-mended that the maximum lateral earth pressure be com-puted by using a seismic coefficient kh � 1.5A in con-junction with the Mononobe-Okabe analysis method.

7.4.3(B) Monolithic Abutments

For monolithic abutments where the abutment formsan integral part of the bridge superstructure, maximumearth pressures acting on the abutment may be assumedequal to the maximum longitudinal earthquake forcetransferred from the superstructure to the abutment. Tominimize abutment damage, the abutment should be de-signed to resist the passive pressure capable of being mo-bilized by the abutment backfill, which should be greaterthan the maximum estimated longitudinal earthquakeforce transferred to the abutment. It may be assumed thatthe lateral active earth pressure during seismic loading isless than the superstructure earthquake load.

When longitudinal seismic forces are also resisted bypiers or columns, it is necessary to estimate abutment stiff-ness in the longitudinal direction in order to compute theproportion of earthquake load transferred to the abutment.

7.4.4 Additional Requirements for Foundations for Seismic Performance Category D

Foundation design requirements for bridges classifiedas SPC D shall meet the requirements of Article 7.4.2 plusthe additional requirements of this section.


The Engineer may require the submission of a writtenreport which includes, in addition to the requirements ofArticle 7.4.2, a site-specific study to investigate the influ-ence of cyclic loading on the deformation and strengthcharacteristics of foundation soils. Potential progressivedegradation in the stiffness and strength characteristics of

470 HIGHWAY BRIDGES 7.4.2(C)


saturated sands and soft clays should be given particularattention. More detailed analyses of slope and/or abut-ment settlement during earthquake loading should be undertaken.


The design forces for foundations shall be those spec-ified in Article 7.2.6.

7.4.5 Additional Requirements for Abutments forSeismic Performance Category D

In addition to the requirements outlined in Article 7.4.3consideration should be given to the mechanism of trans-fer of superstructure longitudinal and transverse inertiaforces to the abutments, and also to abutment-soil inter-action. To minimize potential loss of bridge access arisingfrom abutment damage, monolithic or end diaphragmconstruction is strongly recommended for short spanbridges.

Settlement or approach slabs providing structural sup-port between approach fills and abutments are recom-mended for all bridges classified as SPC D. Slabs shall beadequately linked to abutments using flexible ties.

7.5 STRUCTURAL STEEL DESIGNREQUIREMENTS FOR SEISMICPERFORMANCE CATEGORIES C AND D

7.5.1 General

Design and construction of structural steel columnsand connections shall conform to the requirements of Di-vision I and to the additional requirements of this section.Either Service Load or Load Factor design may be used.If Service Load design is used the allowable stresses arepermitted to increase by 50%. It should be noted thatwhen Service Load design is used for SPC C and D a con-servative design may result because elastic design forceswill be required for the design of most components unlessthe forces resulting from plastic hinging of the columnsare used per Article 7.2.2.

7.5.2 P-delta Effects

Where axial and flexural stresses are determined byconsidering secondary bending resulting from the designP-delta effects (moments induced by the eccentricity re-sulting from the seismic displacements and the columnaxial force), all axially loaded members may be propor-tioned in accordance with Division I, Article 10.36 or10.54.

EXCEPTIONS:

1. The effective length factor, K, in the plane of bend-ing may be assumed to be unity in the calculation of Fa,Fe�, Fcr, or Fe.2. The coefficient Cm is computed as for the caseswhere joint translation is prevented.

7.6 REINFORCED CONCRETE DESIGNREQUIREMENTS FOR SEISMICPERFORMANCE CATEGORIES C AND D

7.6.1 General

Design and construction of cast-in-place monolithicreinforced concrete columns, pier footings and connec-tions shall conform to the requirements of Division I andto the additional requirements of this section. Either Ser-vice Load or Load Factor design may be used. If ServiceLoad design is used the allowable stresses are permittedto increase by 331⁄ 3%. It should be noted that when Ser-vice Load design is used for SPC C and D a conservativedesign may result because elastic design forces will be re-quired for the design of most components unless theforces resulting from plastic hinging of the columns areused per Article 7.2.2.

7.6.2 Column Requirements

For the purpose of these provisions, a vertical supportis considered to be a column if the ratio of the clear heightto the maximum plan dimensions of the support is equalto or greater than 2.5. Note that the maximum plan di-mension is taken at the minimum section of the flare for aflared column. For supports with a ratio less than 2.5, theprovisions for piers of Article 7.6.3 shall apply. Forcolumns the provisions of this section are applicable. Notethat a pier may be designed as a pier in its strong directionand a column in its weak direction.

7.6.2(A) Vertical Reinforcement

The area of longitudinal reinforcement shall not be lessthan 0.01 or more than 0.06 times the gross cross-sectionarea Ag.

EXCEPTION:Division I, Article 8.18.2.1 applies to columns where alarger cross-section is used for architectural reasons.

7.6.2(B) Flexural Strength

The biaxial strength of columns shall not be less thanthat required for the bending moments determined in



Article 7.2.3. The design of the column shall be checkedfor both the minimum and maximum axial loads specifiedin Article 7.2.3. The strength reduction factors of DivisionI, Article 8.16 shall be replaced for both spirally and tiedreinforced columns by the value of 0.50 when the stressdue to the maximum axial load for the column exceeds0.20fc�. The value of � may be increased linearly from0.50 to the value for flexure (0.90) when the stress due tothe maximum axial load is between 0.20fc� and 0.

Moment magnification for slenderness effects (Divi-sion I, Article 8.16.5) shall be considered in the design ofthe column.

7.6.2(C) Column Shear and TransverseReinforcement

The factored design shear force Vu of Division I, Equa-tion (8-46) on each principal axis of each column and pilebent shall be the value determined in Article 7.2.3.

The factored shear stress vu shall be computed using Vu

specified above and the strength reduction factor for shearof Division I, Article 8.16.1.2.

The amount of transverse reinforcement shall be atleast that specified by Division I, Article 8.16.6. In the endregions of the top and bottom of the column and pile bents,the following provisions shall apply in addition to thoseof Division I:

1. The shear strength of the concrete, Vc, shall be inaccordance with Division I, Article 8.16.6.2 when theaxial load associated with the shear produces an aver-age compression stress in excess of 0.1fc� over the coreconcrete area of the support members. As the averagecompression stress increases from 0 to 0.1fc� thestrength Vc increases linearly from 0 to the value givenby Division I, Article 8.16.6.2.2. The end region shall be assumed to extend from the soffit of girders or cap beams at the top of columns,or the top of foundations at the bottom of columns, a distance not less than the minimum of (a) the maxi-mum cross-sectional dimension of the column, (b) one-sixth of the clear height of the column, or (c)18 inches (450 millimeters).3. The end region of a pile bent shall be the same asspecified for columns at the top of the pile bent, andthree pile diameters below the calculated point of mo-ment fixity to one pile diameter, but not less than 18 in-ches (450 millimeters) above the mud line at the bot-tom of the pile bent.

7.6.2(D) Transverse Reinforcement for Confinementat Plastic Hinges

The cores of columns, pile bents, and drilled shaftsshall be confined by transverse reinforcement in the ex-

pected plastic hinge regions, generally located at the topand bottom of columns and pile bents, as specified in thissubsection. The largest of these requirements or those ofArticle 7.6.2(C) shall govern; these requirements are notin addition to those of Article 7.6.2(C). The transverse re-inforcement for confinement shall have a yield strengthnot more than that of the longitudinal reinforcement andthe spacing shall be as specified in Article 7.6.2(E).

The volumetric ratio of spiral reinforcement (�s) for acircular column shall be either that required in Division I,Article 8.18 or,

or,

whichever is greater.The total cross-sectional area (Ash) of rectangular hoop

(stirrup) reinforcement for a rectangular column shall beeither,

or,

whichever is greater, where:

a � vertical spacing of hoops (stirrups) in inches(millimeters) with a maximum of 4 inches (100millimeters).

Ac � area of column core measured to the outside ofthe transverse spiral reinforcement.

Ag � gross area of column.Ash � total cross-sectional area in square inches

(square millimeters) of hoop (stirrup) reinforce-ment including supplementary cross-ties havinga vertical spacing of an inches (millimeters) andcrossing a section having a core dimension of hc

inches (millimeters). Note that this should becalculated for both principal axes of a rectangu-lar column.

fc� � specified compressive strength of concrete inpsi (MPa).

fyh � yield strength of hoop or spiral reinforcement inpsi (MPa).

A ahffsh c

c

yh= ′

0 12 7. ( - 7)

A ahf

f

A

Ash cc

yh

g

c

= ′ −

0 30 1. (7 - 6)

ρsc

yh

f

f= ′

0 12 7. ( - 5)

ρsg

c

c

yh

A

A

f

f= −

′0 45 1 7. ( - 4)



hc � core dimension of tied column in inches (mil-limeters) in the direction under consideration.

�s � ratio of volume of spiral reinforcement to totalvolume of concrete core (out-to-out of spirals).

Transverse hoop reinforcement may be provided bysingle or overlapping hoops. Cross-ties having the samebar size as the hoop may be used. Each end of the cross-tie shall engage a peripheral longitudinal reinforcing bar.A crosstie is a continuous bar having a hook of not lessthan 135° with an extension of not less than six-diameter,but not less than 3 inches (76 millimeters), at one end anda hook of not less than 90° with an extension of not lessthan six-diameter at the other end. The hooks shall engageperipheral longitudinal bars. The 90° hooks of two suc-cessive crossties engaging the same longitudinal barsshall be alternated end for end.

A hoop is a closed tie or continuously wound tie. Aclosed tie may be made up of several reinforcing elementswith 135° hooks having a six-diameter, but not less than 3inches (76 millimeters), extension at each end. A continu-ously wound tie shall have at each end a 135° hook with asix-diameter, but not less than 3 inches (76 millimeters),extension that engages the longitudinal reinforcement.

7.6.2(E) Spacing of Transverse Reinforcement for Confinement

1. Transverse reinforcement for confinement shall beprovided at the top and bottom of the column over alength equal to the maximum cross-sectional columndimension or one-sixth of the clear height of the col-umn, whichever is the larger, but not less than 18inches (450 millimeters). Transverse reinforcementshall be extended into the top and bottom connectionsas specified in Article 7.6.4.2. Transverse reinforcement for confinement shall beprovided at the top of piles in pile bents over the samelength as specified for columns. At the bottom of pilesin pile bents, transverse reinforcement for confinementshall be provided over a length extending from threepile diameters below the calculated point of momentfixity to one pile diameter but not less than 18 inches(450 millimeters) above the mud line.3. The maximum spacing for reinforcement shall notexceed the smaller of one-quarter of the minimummember dimension or 4 inches (100 millimeters).4. Lapping of spiral reinforcement in the transverseconfinement regions specified in 1 and 2 shall not bepermitted. Connections of spiral reinforcement in thisregion must be full strength lap welds.

7.6.2(F) Splices

Splices shall be in accordance with those specified inDivision I, Article 8.32 and the additional requirements of

this Article. Lap splices shall be permitted only within thecenter half of column height, and the splice length shallnot be less than 16 inches (400 millimeters) or 60 bar di-ameters, whichever is greater.

The maximum spacing of the transverse reinforcementover the length of the splice shall not exceed the smallerof 4 inches (100 millimeters) or one-quarter of the mini-mum member dimension.

Welded splices and approved mechanical splices thatconform to the current provisions of ACI 318 may be usedfor splicing provided that splices shall not be used on anytwo adjacent bars in the same layer of longitudinal rein-forcement at the same section and that the distance between splices of adjacent bars is greater than 24 inches (600 millimeters) as measured along the longitudinal axisof the column.

7.6.3 Pier Requirements

The provisions of this article are applicable to the de-sign for the strong direction of a pier. The weak directionof a pier may be designed as a column and the provisionsof Article 7.6.2 are then applicable. In this case, the Re-sponse Modification Factor for columns may be used todetermine the design forces in Article 7.2.1. If the pier isnot designed as a column in its weak direction, the limita-tions for shear stress in this article are applicable.

The minimum reinforcement ratio both horizontally,�h, and vertically �n, in any pier shall not be less than0.0025. Reinforcement spacing either horizontally or ver-tically shall not exceed 18 inches (457 millimeters). Thereinforcement required for shear shall be continuous andshall be distributed uniformly.

�h � the ratio of horizontal shear reinforcement areato gross concrete area of a vertical section.

�n � the ratio of vertical shear reinforcement area tothe gross concrete area of a horizontal section.

The allowable shear stress, vu, in the pier shall be de-termined in accordance with the following equation:

The allowable shear stress shall not exceed 8�fc��. Forlightweight aggregate concrete, the limiting shear stress,vu, calculated from Equation (7-8), shall be multiplied by0.75. Two curtains of reinforcement shall be used and thereinforcement ratios �n and �h shall be equal. The rein-forcement required by shear shall be uniformly distrib-uted. Splices in horizontal pier reinforcement shall bestaggered and splices in the two curtains shall not occur atthe same location.

v f fu c h y= ′ +2 7ρ ( - 8)

7.6.2(D) DIVISION IA—SEISMIC DESIGN 473


7.6.4 Column Connections

A column connection as referred to in this section is thevertical extension of the column area into the adjoiningmember.

The design force for the connection between the col-umn and the cap beam superstructure, pile cap, or spreadfooting shall be that specified in Article 7.2.5(C). The de-velopment length for all longitudinal steel shall be that re-quired for a steel stress of 1.25fy as given in Division I, Ar-ticles 8.24 through 8.32.

Column transverse reinforcement required by Article7.6.2(D) shall be continued for a distance equal to one-half the maximum column dimension but not less than 15inches (375 millimeters) from the face of the column con-nection into the adjoining member.

The shear stress in the joint of a frame or bent, in thedirection under consideration, shall not exceed 12�fc�� fornormal-weight aggregate concrete or 9�fc�� for light-weight aggregate concrete.

7.6.5 Construction Joints in Piers and Columns

Construction joints in piers and columns resisting seis-mic forces shall be designed and constructed to resist thedesign forces at the joint.

Where shear is resisted at a construction joint solely bydowel action and friction on a roughened concrete sur-face, the total shear force across the joint shall not exceedVj determined from the following formula:

Vj � �(Avffy � 0.75Pn) (7-9)

where Avf is the total area of reinforcement (includingflexural reinforcement), Pn is the minimum axial loadspecified in Article 7.2.3 for columns and Article 7.2.4 forpiers, and � is the strength reduction factor for shear ofDivision I, Article 8.16.



Division IICONSTRUCTION


INTRODUCTION

476

This Division of the Standard Specifications for High-way Bridges includes the basic technical construction spec-ifications needed for the construction of bridges and othermajor transportation structures. They generally representcurrent practices in the United States and are consistentwith the AASHTO Design Specifications for Bridgeswhich are contained in Division I. They are provided to beused either as part of the specifications for projects or asa guide for agencies in developing their own standards.When so used, uniformity and the efficiencies associatedtherewith may be realized.

These technical specifications do not include theclauses needed for the administration of a contract andwere written to be used in conjunction with general pro-visions such as those in the AASHTO Guide Specifica-tions for Highway Construction. Other comparable sets ofgeneral provision clauses currently in use by many Statescan also be used to cover the administration requirementsfor construction contracts. The Guide Specifications andthese Standard Specifications are intended to be comple-mentary and to provide for the principal and most widely

used items of work required for the construction of majortransportation structures. Note that these specifications donot identify the date of specifications, which are includedby reference, such as the AASHTO Standard Specifica-tions for Transportation Materials and Methods of Testingand Sampling. As required by the AASHTO Guide Spec-ification, the edition of such specifications incorporatedby reference will be the edition in effect on the date of ad-vertisement for proposals for the project.

Sufficient detail may not be included in these specifi-cations to suit local or unusual conditions or unique de-signs. The many differences in climate, geology, customs,statutes and regulations prevent the writing of a more de-tailed national construction specification. Therefore, theuser is expected to supplement or alter the requirementsof these specifications, as needed, in the project specialprovisions. A Commentary is provided to assist the user indeveloping such special provisions.

These specifications were extensively revised underNCHRP 12-34 in 1989 and approved by AASHTO High-way Subcommittee on Bridges and Structures in 1990.


477

Section 1STRUCTURE EXCAVATION AND BACKFILL

1.1 GENERAL

Structure excavation shall consist of the removal of allmaterial, of whatever nature, necessary for the construc-tion of foundations for bridges, retaining walls, and othermajor structures in accordance with the plans or as di-rected by the Engineer.

If not otherwise provided for in the contract, struc-ture excavation shall include the furnishing of all neces-sary equipment and the construction and subsequentremoval of all cofferdams, shoring, and water controlsystems which may be necessary for the execution of the work.

It shall also include, if not otherwise specified, theplacement of all necessary backfill, including any neces-sary stockpiling of excavated material which is to be usedin backfill, and the disposing of excavated material, whichis not required for backfill, in roadway embankments oras provided for excess and unsuitable material in Subsec-tion 203.02, AASHTO Guide Specifications for HighwayConstruction.

If the contract does not include a separate pay item or items for such work, structure excavation shall include all necessary clearing and grubbing and the re-moval of existing structures within the area to be exca-vated.

Classification, if any, of excavation will be indicatedon the plans and set forth in the proposal.

The removal and disposal of buried natural ormanmade objects are included in the class of excavationin which they are located, unless such removal anddisposal are included in other items of work. However, inthe case of a buried manmade object, if (1) its removalrequires the use of methods or equipment not used forother excavation on the project, (2) its presence was not indicated on the plans or in the special provisions, (3) its presence could not have been ascertained by siteinvestigation, including contact with identified utilitieswithin the area, and (4) the Contractor so requests in writing prior to its removal, the removal and disposal of such object will be paid for as extra work, and itsvolume will not be included in the measured quantity ofexcavation.

1.2 WORKING DRAWINGS

Whenever specified, the Contractor shall provideworking drawings, accompanied by calculations whereappropriate, of excavation procedures, embankment con-struction and backfilling operations. This plan shall showthe details of shoring, bracing, slope treatment or otherprotective system proposed for use and shall be accompa-nied by design calculations and supporting data in suffi-cient detail to permit an engineering review of the pro-posed design.

The working drawings and plans for protection fromcaving shall be submitted sufficiently in advance of pro-posed use to allow for their review, revision, if needed,and approval without delay to the work.

Working drawings must be approved by the Engineerprior to performance of the work involved and such ap-proval shall not relieve the Contractor of any responsibil-ity under the contract for the successful completion of thework.

1.3 MATERIALS

Material used for backfill shall be free of frozen lumps,wood or other degradable matter and shall be of a gradingsuch that the required compaction can be consistently ob-tained using the compaction methods selected by the Con-tractor.

Permeable material for underdrains shall conform toAASHTO Guide Specifications for Highway Construc-tion, Subsection 704.01.

1.4 CONSTRUCTION

1.4.1 Depth of Footings

The elevation of the bottoms of footings, as shown onthe plans, shall be considered as approximate only and theEngineer may order, in writing, such changes in dimen-sions or elevation of footings as may be necessary to se-cure a satisfactory foundation.


1.4.2 Foundation Preparation and Control of Water

1.4.2.1 General

All substructures, where practical, shall be constructedin open excavation and, where necessary, the excavationshall be shored, braced, or protected by cofferdams con-structed in accordance with the requirements contained inArticle 3.3, “Cofferdams and Shoring.” When footingscan be placed in the dry without the use of cofferdams,backforms may be omitted with the approval of the Engi-neer, and the entire excavation filled with concrete to therequired elevation of the top of the footing. The additionalconcrete required shall be furnished and placed at the ex-pense of the Contractor. Temporary water control systemsshall conform to the requirements contained in Article 3.4,“Temporary Water Control Systems.”

1.4.2.2 Excavations Within Channels

When excavation encroaches upon a live stream bed orchannel, unless otherwise permitted, no excavation shallbe made outside of caissons, cribs, cofferdams, steel pil-ing, or sheeting, and the natural stream bed adjacent to thestructure shall not be disturbed without permission fromthe Engineer. If any excavation or dredging is made at thesite of the structure before caissons, cribs, or cofferdamsare sunk or are in place, the Contractor shall, without extracharge, after the foundation base is in place, backfill allsuch excavation to the original ground surface or river bedwith material satisfactory to the Engineer. Material tem-porarily deposited within the flow area of streams fromfoundation or other excavation shall be removed and thestream flow area freed from obstruction thereby.

1.4.2.3 Foundations on Rock

When a foundation is to rest on rock, the rock shall befreed from all loose material, cleaned and cut to a firm sur-face, either level, stepped, or roughened, as may be di-rected by the Engineer. All seams shall be cleaned out andfilled with concrete, mortar, or grout before the footing isplaced.

Where blasting is required to reach footing level, anyloose, fractured rock caused by overbreak below bearinglevel shall be removed and replaced with concrete orgrouted at the Contractor’s expense.

1.4.2.4 Other Foundations

When a foundation is to rest on an excavated surfaceother than rock, special care shall be taken not to disturbthe bottom of the excavation, and the final removal of the

foundation material to grade shall not be made until justbefore the footing is to be placed.

Where the material below the bottom of footings notsupported by piles has been disturbed, it shall be removedand the entire space filled with concrete or other approvedmaterial at the Contractor’s expense. Under footings sup-ported on piles, the over-excavation or disturbed volumesshall be replaced and compacted as directed by the Engi-neer.

1.4.2.5 Approval of Foundation

After each excavation is completed, the Contractorshall notify the Engineer, and no concrete or other footingmaterial shall be placed until the Engineer has approvedthe depth of the excavation and the character of the foun-dation material.

1.4.3 Backfill

Backfill material shall conform to the provisions of Ar-ticle 1.3. If sufficient material of suitable quality is notavailable from excavation within the project limits, theContractor shall import such material as directed by theEngineer.

All spaces excavated and not occupied by abutments,piers, or other permanent work shall be refilled with earthup to the surface of the surrounding ground, with a suffi-cient allowance for settlement. Except as otherwise pro-vided, all backfill shall be thoroughly compacted to thedensity of the surrounding ground, and its top surfaceshall be neatly graded. Fill placed around piers shall bedeposited on both sides to approximately the same eleva-tion at the same time. Rocks larger than 3 inches maxi-mum dimension shall not be placed against the concretesurfaces.

Embankment construction shall conform to the re-quirements of Subsection 203.02, AASHTO Guide Spec-ifications for Highway Construction. The fill at retainingwalls, abutments, wingwalls, and all bridge bents in em-bankment shall be deposited in well-compacted, horizon-tal layers not to exceed 6 inches in thickness and shall bebrought up uniformly on all sides of the structure or facil-ity. Backfill within or beneath embankments, within theroadway in excavated areas, or in front of abutments andretaining walls or wingwalls shall be compacted to thesame density as required for embankments.

No backfill shall be placed against any concrete struc-ture until permission has been given by the Engineer. Theplacing of such backfill shall also conform to the require-ments of Article 8.15.2, “Earth Loads.” The backfill infront of abutments and wingwalls shall be placed first toprevent the possibility of forward movement. Jetting of



the fill behind abutments and wingwalls will not be per-mitted.

Adequate provision shall be made for the thoroughdrainage of all backfill. French drains, consisting of atleast 2 cubic feet of permeable material wrapped in filterfabric to prevent clogging and transmission of fines fromthe backfill, shall be placed at weep holes.

Backfilling of metal and concrete culverts shall bedone in accordance with the requirements of Sections 26,“Metal Culverts,” and 27, “Concrete Culverts.”

1.5 MEASUREMENT AND PAYMENT

1.5.1 Measurement

The quantity to be paid for as structure excavation shallbe measured by the cubic yard. The quantities for paymentwill be determined from limits shown on the plans, in-cluded in the specifications, or ordered by the Engineer.No deduction in structure excavation pay quantities willbe made where the Contractor does not excavate materialwhich is outside the limits of the actual structure butwithin the limits of payment for structure excavation.

In the absence of plans or special provisions indicatingpay limits for structure excavation, the horizontal limitswill be vertical planes 18 inches outside of the neat linesof footings or structures without footings; the top limitsshall be the original ground or the top of the required grad-ing cross section, whichever is lower; and the lower lim-its shall be the bottom of the footing or base of structure,or the lower limit of excavation ordered by the Engineer.When foundations are located within embankments andthe specifications require the embankment to be con-structed to a specified elevation which is above the bottomof the footing or base of structure prior to construction ofthe foundation, then such specified elevation will be con-sidered to be the original ground.

When it is necessary, in the opinion of the Engineer, tocarry the foundations below the elevations shown on theplans, the excavation for the first 3 feet of additional depth

will be included in the quantity for which payment will bemade under this item. Excavation below this additionaldepth will be paid for as extra work, unless the Contrac-tor states in writing that payment at contract prices is ac-ceptable.

1.5.2 Payment

Unless otherwise provided, structure excavation, mea-sured as provided in Article 1.5.1, will be paid for by thecubic yard for the kind and class specified.

Payment for structure excavation shall include fullcompensation for all labor, material, equipment, and otheritems that may be necessary or convenient to the success-ful completion of the excavation to the elevation of thebottom of footings or base of structure.

Full compensation for controlling and removing waterfrom excavations and for furnishing and installing or con-structing all cofferdams, shoring, and all other facilitiesnecessary to the operations, except concrete seal courseswhich are shown on the plans, and their subsequent re-moval, shall be considered as included in the contractprice for structure excavation, unless the contract pro-vides for their separate payment.

The contract price for structure excavation shall in-clude full payment for all handling and storage of exca-vated materials which are to be used as backfill, includingany necessary drying, and the disposal of all surplus or un-suitable excavated materials, unless otherwise providedfor in the contract. Any clearing, grubbing, or structure re-moval which is required, but not paid for under otheritems of the contract, will be considered to be included inthe price paid for structure excavation.

Unless the contract provides for its separate payment,the contract price for structure excavation shall includefull compensation for the placing and compacting ofstructure backfill. The furnishing of backfill material fromsources other than excavation will be paid for at the con-tract unit price for the material being used, or as extrawork if no unit price has been established.

1.4.3 DIVISION II—CONSTRUCTION 479


Section 2REMOVAL OF EXISTING STRUCTURES

2.1 DESCRIPTION

This work shall consist of the removal, wholly or inpart, and satisfactory disposal, or salvage, of all bridges,retaining walls and other major structures which are des-ignated on the plans or in the special provisions to be re-moved. The work also includes, unless otherwise speci-fied, any necessary excavation and the backfilling oftrenches, holes or pits that result from such removal.


Working drawings showing methods and sequence ofremoval shall be prepared: (1) when structures or portionsof structure are specified to be removed and salvaged, (2)when removal operations will be performed over or adja-cent to public traffic or railroad property, or (3) whencalled for by the plans or special provisions. At least 10days prior to the proposed start of removal operations, theworking drawings shall be submitted to the Engineer forapproval. Removal work shall not begin until the draw-ings have been approved. Such approval shall not relievethe Contractor of any responsibility under the contract forthe successful completion of the work.

When salvage is required, the drawings shall clearlyindicate the markings proposed to designate individualsegments of the structure.

2.3 CONSTRUCTION

2.3.1 General

Except for utilities and other items that the Engineermay direct the Contractor to leave intact, the Contractorshall raze, remove and dispose of each structure, or por-tion of structure, designated to be removed. All concreteand other foundations shall be removed to a depth of atleast 2 feet below ground elevation or 3 feet below sub-grade elevation, whichever is lower. Unless otherwisespecified, the Contractor has the option to either pull pilesor cut them off at a point not less than 2 feet below groundline. Cavities left from structure removal shall be back-

filled to the level of the surrounding ground and, if withinthe area of roadway construction, shall be compacted tomeet the requirements of the contract for embankment.

Explosives shall not be used except at locations andunder conditions cited by the project specifications. Allblasting shall be completed before the placement of newwork.

2.3.2 Salvage

Materials which are designated to be salvaged underthe contract, for reuse in the project or for future use bythe Department, shall remain the property of the Depart-ment and shall be carefully removed in transportable sec-tions and stockpiled near the site at a location designatedby the Engineer. The Contractor shall restore or replacedamaged or destroyed material without additional com-pensation.

Rivets and bolts that must be removed from steel struc-tures to be salvaged shall be removed by cutting the headswith a chisel, then punched or drilled from the hole, or bya method that will not injure the members for reuse andwill meet the approval of the Engineer. All members orsections of steel structures shall be match-marked withpaint in accordance with the diagram or plan approved bythe Engineer prior to dismantling.

All bolts and nails shall be removed from lumberdeemed salvageable by the Engineer as part of the salvageof timber structures.

2.3.3 Partial Removal of Structures

When structures are to be widened or modified andonly portions of the existing structure are to be removed,these portions shall be removed in such a manner as toleave the remaining structure undamaged and in propercondition for the use contemplated. Methods involvingthe use of blasting or wrecking balls shall not be usedwithin any span or pier unless the entire span or pier is tobe removed. Any damage to the portions remaining in ser-vice shall be repaired by the Contractor at his or her ex-pense.

481


Before beginning concrete removal operations involv-ing the removal of a portion of a monolithic concrete element, a saw cut approximately 1-inch deep shall bemade to a true line along the limits of removal on all facesof the element which will be visible in the completedwork.

Old concrete shall be carefully removed to the linesdesignated by drilling, chipping, or other methods ap-proved by the Engineer. The surfaces presented as a re-sult of this removal shall be reasonably true and even,with sharp straight corners that will permit a neat andworkmanlike joint with the new construction or be satis-factory for the purpose intended. Where existing rein-forcing bars are to extend from the existing structure intonew construction, the concrete shall be removed so as toleave the projecting bars clean and undamaged. Whereprojecting bars are not to extend into the new construc-tion, they shall be cut off flush with the surface of the oldconcrete.

During full depth removal of deck concrete over steelbeams or girders which are to remain in place, the Con-tractor shall exercise care so as not to notch, gouge, or dis-tort the top flanges with jackhammers or other tools. Anydamage shall be repaired at the Contractor’s expense. Re-pairs will be done as directed by the Engineer and may in-clude grinding, welding, heat straightening, or memberreplacement, depending on the location and severity of thedamage.

2.3.4 Disposal

Any material not designated for salvage will belong tothe Contractor. Except as provided herein, the Contractorshall store or dispose of such material outside of the rightof way. If the material is disposed of on private property,the Contractor shall secure written permission from the

property owner and shall furnish a copy of each agree-ment to the Engineer. Waste materials may be disposed ofin Department-owned sites when such sites are describedin the special provisions.

Unless otherwise provided in the special provisions,removed concrete may be buried in adjacent embank-ments, provided it is broken into pieces which can bereadily handled and incorporated into embankments andis placed at a depth of not less than 3 feet below finishedgrade and slope lines. The removed concrete shall not beburied in areas where piling is to be placed or within 10feet of trees, pipelines, poles, buildings, or other perma-nent objects or structures, unless permitted by the Engi-neer. Removed concrete may also be disposed of outsidethe right-of-way as provided above.


The work as prescribed for by this item shall be mea-sured as each individual structure, or portion of a struc-ture, to be removed. Payment will be made on the basis ofthe lump sum bid price for the removal of each structure,or portion of structure, as specified.

The above prices and payments shall be full compen-sation for all work, labor, tools, equipment, excavation,backfilling, materials, and incidentals necessary to com-plete the work, including salvaging materials not to bereused in the project when such salvaging is specified andnot otherwise paid for.

Full compensation for removing and salvaging materi-als that are to be reused in the project shall be consideredas included in the contract prices paid for reconstructing,relocating or resetting the items involved, or in such othercontract pay items that may be designated in the contract,and no additional compensation will be allowed therefore.



Section 3TEMPORARY WORKS

3.1 GENERAL

3.1.1 Description

This work shall consist of the construction and re-moval of temporary facilities which are generally de-signed by the Contractor and employed by the Contractorin the execution of the work and whose failure to performproperly could adversely affect the character of thecontract work or endanger the safety of adjacent facil-ities, property, or the public. Appropriate reductions inallowable stresses or loads shall be used for design when other than new or undamaged materials are to beused. Such facilities include, but are not limited to, false-work, forms and form travelers, cofferdams, shoring,water control systems, and temporary bridges.

The following publications are useful reference docu-ments in the preparation of specifications for the design,review and inspection of temporary works:

Synthesis of Falsework, Formwork, and Scaffoldingfor Highway Bridge Structures, November 1991,(FHWA-RD-91-062)

Guide Standard Specifications for Bridge TemporaryWorks, November 1993, (FHWA-RD-93-031)

Guide Design Specification for Bridge TemporaryWorks, November 1993, (FHWA-RD-93-032)

Certification Program for Bridge Temporary Works,November 1993, (FHWA-RD-93-033)

Construction Handbook for Bridge TemporaryWorks, November 1993, (FHWA-RD-93-034)

3.1.2 Working Drawings

Whenever specified or requested by the Engineer, theContractor shall provide working drawings with designcalculations and supporting data in sufficient detail to per-mit a structural review of the proposed design of a tem-porary work. When concrete is involved, such data shallinclude the sequence and rate of placement. Sufficientcopies shall be furnished to meet the needs of the Engi-neer and other entities with review authority. The working

drawings shall be submitted sufficiently in advance ofproposed use to allow for their review, revision, if needed,and approval without delay to the work.

The Contractor shall not start the construction of anytemporary work for which working drawings are requireduntil the drawings have been approved by the Engineer.Such approval will not relieve the Contractor of responsi-bility for results obtained by use of these drawings or anyof his other responsibilities under the contract.

3.1.3 Design

The design of temporary works shall conform to theAASHTO Standard Specifications for Highway Bridgesor the Guide Design Specifications for Bridge TemporaryWorks; or to other established and generally accepted de-sign code or specification for such work.

When manufactured devices are to be employed, thedesign shall not result in loads on such devices in excessof the load ratings recommended by their manufacturer.For equipment where the rated capacity is determined byload testing, the design load shall be as stated in the GuideDesign Specifications for Bridge Temporary Works.

The load rating used for special equipment, such as ac-cess scaffolding, may be under the jurisdiction of OSHAand/or other State/local regulations. However, in no caseshall the rating exceed 80% of the maximum load sus-tained during load testing of the equipment.

When required by statute or specified in the contractdocuments, the design shall be prepared and the drawingssigned by a Registered Professional Engineer.

3.1.4 Construction

Temporary works shall be constructed in conformancewith the approved working drawings. The Contractor shallverify that the quality of the materials and workmanshipemployed are consistent with that assumed in the design.

3.1.5 Removal

Unless otherwise permitted, all temporary works shallbe removed and shall remain the property of the Contrac-tor upon completion of their use. The area shall be re-

483


stored to its original or planned condition and cleaned ofall debris.

3.2 FALSEWORK AND FORMS

3.2.1 General

Falsework is considered to be any temporary structurewhich supports structural elements of concrete, steel, ma-sonry, or other materials during their construction or erec-tion. Forms are considered to be the enclosures or panelswhich contain the fluid concrete and withstand the forcesdue to its placement and consolidation. Forms may in turnbe supported on falsework. Form travelers, as used in seg-mental cantilever construction, are considered to be acombination of falsework and forms.

Whenever the height of falsework exceeds 14 feet orwhenever traffic, other than workmen involved in con-structing the bridge, will travel under the bridge, theworking drawings for the falsework shall be prepared andsealed by a Registered Engineer.

Falsework and forms shall be of sufficient rigidity andstrength to safely support all loads imposed, and producein the finished structure the lines and grades indicated onthe plans. Forms shall also impart the required surfacetexture and rustication, and shall not detract from the uni-formity of color of formed surfaces.

3.2.2 Falsework Design and Construction

3.2.2.1 Loads

The design load for falsework shall consist of the sum of dead and live vertical loads, and any horizontalloads.

As a minimum, dead loads shall include the weight ofthe falsework and all construction material to be sup-ported. The combined weight of concrete, reinforcing andprestressing steel and forms shall be assumed to be notless than 160 pounds per cubic foot of normal weight con-crete or 130 pounds per cubic foot of lightweight concretethat is supported.

Live loads shall consist of the actual weight of anyequipment to be supported applied as concentrated loadsat the points of contact and a uniform load of not less than20 pounds per square foot applied over the area supported,plus 75 pounds per linear foot applied at the outside edgeof deck overhangs.

The horizontal load used for the design of thefalsework bracing system shall be the sum of the horizon-tal loads due to equipment, construction sequence, in-cluding unbalanced hydrostatic forces from fluidconcrete, stream flow when applicable, and an allowance

for wind. However, in no case shall the horizontal load tobe resisted in any direction be less than 2% of the totaldead load.

For post-tensioned structures, the falsework shall alsobe designed to support any increased or redistribution ofloads caused by prestressing of the structure.

Loads imposed by falsework onto existing, new or par-tially completed structures shall not exceed those permit-ted in Article 8.15, “Application of Loads.”

3.2.2.2 Foundations

Falsework shall be founded on a solid footing safeagainst undermining, protected from softening, and capa-ble of supporting the loads imposed on it. When requestedby the Engineer, the Contractor shall demonstrate by suit-able load tests that the soil bearing values assumed for thedesign of the falsework footings do not exceed the sup-porting capacity of the soil.

Falsework which cannot be founded on a satisfactoryfooting shall be supported on piling which shall bespaced, driven, and removed in an approved manner.

3.2.2.3 Deflections

For cast-in-place concrete structures, the calculated de-flection of falsework flexural members shall not exceed1/240 of their span irrespective of the fact that the deflec-tion may be compensated for by camber strips.

3.2.2.4 Clearances

Unless otherwise provided, the minimum dimensionsof clear openings to be provided through falsework forroadways which are to remain open to traffic during con-struction shall be at least 5 feet greater than the width ofthe approach traveled way, measured between barrierswhen used, and 14 feet high, except that the minimumvertical clearance over interstate routes and freeways shallbe 14.5 feet.

3.2.2.5 Construction

Falsework shall be constructed and set to grades whichallow for its anticipated settlement and deflection, and forthe vertical alignment and camber indicated on the plansor ordered by the Engineer for the permanent structure.Variable depth camber strips shall be used between false-work beams and soffit forms to accomplish this when di-rected by the Engineer.

Suitable screw jacks, pairs of wedges or other devicesshall be used at each post to adjust falsework to grade, topermit minor adjustments during the placement of con-



crete or structural steel should observed settlements de-viate from those anticipated, and to allow for the gradualrelease of the falsework. Telltales attached to the formsand extending to the ground, or other means, shall beprovided by the Contractor for accurate measurement offalsework settlement during the placing and curing of theconcrete.

Falsework or formwork for deck slabs on girderbridges shall be supported directly on the girders so thatthere will be no appreciable differential settlement duringplacing of the concrete. Girders shall be braced and tiedto resist any forces that would cause rotation or torsion inthe girders caused by the placing of concrete for di-aphragms or deck. Welding of falsework support bracketsor braces to structural steel members or reinforcing steelwill not be allowed unless specifically permitted.

3.2.3 Formwork Design and Construction

3.2.3.1 General

Forms shall be of wood, steel, or other approved mate-rial and shall be mortar tight and of sufficient rigidity toprevent objectional distortion of the formed concrete sur-face due to pressure of the concrete and other loads inci-dental to the construction operations.

Forms for concrete surfaces exposed to view shall pro-duce a smooth surface of uniform texture and color sub-stantially equal to that which would be obtained with theuse of plywood conforming to the National Institute ofStandards and Technology Product Standard PSI for Ex-terior B-B Class I Plywood. Panels lining such forms shallbe arranged so that the joint lines form a symmetrical pat-tern conforming to the general lines of the structure. Thesame type of form lining material shall be used through-out each element of a structure. Such forms shall be suf-ficiently rigid so that the undulation of the concrete sur-face shall not exceed 1 ⁄8 inch when checked with a5-foot-long straightedge or template. All sharp cornersshall be filleted with approximately 3 ⁄4-inch chamferstrips.

Concrete shall not be deposited in the forms until allwork connected with constructing the forms has beencompleted, all debris has been removed, all materials tobe embedded in the concrete have been placed for the unitto be cast, and the Engineer has inspected the forms andmaterials.

3.2.3.2 Design

The structural design of formwork shall conform toACI Standard, “Recommended Practice for ConcreteFormwork,” (ACI 347) or some other generally accepted

standard. In selecting the hydrostatic pressure to be usedin the design of forms, consideration shall be given to themaximum rate of concrete placement to be used, the ef-fects of vibration, the temperature of the concrete and anyexpected use of set-retarding admixtures or pozzolanicmaterials in the concrete mix.


Forms shall be set and held true to the dimensions,lines and grades of the structure prior to and during theplacement of concrete. Forms may be given a bevel ordraft at projections, such as copings, to ensure easy re-moval. Prior to reuse, forms shall be cleaned, inspectedfor damage and, if necessary, repaired. When forms ap-pear to be defective in any manner, either before or dur-ing the placement of concrete, the Engineer may order thework stopped until defects have been corrected.

Forms shall be treated with form oil or other approvedrelease agent before the reinforcing steel is placed. Mate-rial which will adhere to or discolor the concrete shall notbe used.

Except as provided herein, metal ties or anchorageswithin the forms shall be so constructed as to permit theirremoval to a depth of at least 1 inch from the face withoutinjury to the concrete. Ordinary wire ties may be usedonly when the concrete will not be exposed to view andwhere the concrete will not come in contact with salts orsulfates. Such wire ties, upon removal of the forms, shallbe cut back at least 1 ⁄4 inch from the face of the concretewith chisels or nippers; for green concrete, nippers shallbe used. Fittings for metal ties shall be of such design that,upon their removal, the cavities that are left will be of thesmallest possible size. The cavities shall be filled with ce-ment mortar and the surface left sound, smooth, even, anduniform in color.

When epoxy-coated reinforcing steel is required, allmetal ties, anchorages or spreaders which will remain inthe concrete shall be of corrosion resistant material orcoated with a dielectric material.

For narrow walls and columns, where the bottom of theform is inaccessible, an access opening shall be providedin the forms for cleaning out extraneous material imme-diately before placing the concrete.

3.2.3.4 Tube Forms

Tubes used as forms to produce voids in concrete slabsshall be properly designed and fabricated or otherwisetreated to make the outside surface waterproof. Prior toconcrete placement such tubes shall be protected from theweather and stored and installed by methods that preventdistortion or damage. The ends of tube forms shall be cov-

3.2.2.5 DIVISION II—CONSTRUCTION 485


ered with caps that shall be made mortar tight and water-proof. If wood or other material that expands when moistis used for capping tubes, a premolded rubber joint filler1 ⁄4 inch in thickness shall be used around the perimeter ofthe caps to permit expansion. A PVC vent tube shall beprovided near each end of each tube. These vents shall beconstructed to provide positive venting of the voids. Afterexterior form removal, the vent tube shall be trimmed towithin 1 ⁄2 inch of the bottom surface of the finished con-crete.

Anchors and ties for tube forms shall be adequate toprevent displacement of the tubes during concrete place-ment.

3.2.3.5 Stay-in-Place Forms

Stay-in-place deck soffit forms, such as corrugatedmetal or precast concrete panels, may be used if shown on the plans or approved by the Engineer. Prior tothe use of such forms the Contractor shall provide a com-plete set of details to the Engineer for review andapproval. The detailed plans for structures, unless other-wise noted, are dimensioned for the use of removableforms and any changes necessary to accommodate stay-in-place forms, if approved, shall be at the expenseof the Contractor.

3.2.4 Removal of Falsework and Forms

3.2.4.1 General

Falsework or forms shall not be removed without ap-proval of the Engineer. In the determination of the time forthe removal of falsework and forms, consideration shallbe given to the location and character of the structure, theweather, the materials used in the mix, and other condi-tions influencing the early strength of the concrete.

Methods of removal likely to cause overstressing of theconcrete or damage to its surface shall not be used. Sup-ports shall be removed in such a manner as to permit thestructure to uniformly and gradually take the stresses dueto its own weight. For arch structures of two or morespans, the sequence of falsework release shall be as spec-ified or approved.

3.2.4.2 Time of Removal

If field operations are not controlled by beam or cylin-der tests, the following minimum periods of time, exclu-sive of days when the temperature is below 40F, shallhave elapsed after placement of concrete before falseworkis released or forms are removed:

Falsework for:Spans over 14 feet 14 daysSpans of 14 feet or less 10 daysBent caps not yet supporting girders 10 days

Forms:Not supporting the dead 24 hoursweight of the concrete

For interior cells of box 12 hoursgirders and for railings

If high early strength is obtained with Type III cementor by the use of additional cement, these periods may bereduced as directed.

When field operations are controlled by cylinder tests,the removal of supporting forms or falsework shall notbegin until the concrete is found to have the specifiedcompressive strength, provided further that in no caseshall supports be removed in less than 7 days after plac-ing the concrete.

In addition to the above time requirements:

Forms shall not be removed until the concrete hassufficient strength to prevent damage to the surface.

Falsework for post-tensioned portions of structuresshall not be released until the prestressing steel hasbeen tensioned.

Falsework supporting any span of a continuous orrigid frame bridge shall not be released until theaforementioned requirements have been satisfiedfor all of the structural concrete in that span and inthe adjacent portions of each adjoining span for alength equal to at least one-half the length of thespan where falsework is to be released.

Unless otherwise specified or approved, falseworkshall be released before the railings, copings or barriersare placed for all types of bridges. For arch bridges, thetime of falsework release relative to the construction of el-ements of the bridge above the arch shall be as shown onthe plans or directed by the Engineer.

3.2.4.3 Extent of Removal

All falsework and forms shall be removed except:

Portions of driven falsework piles more than 1 footbelow subgrade within roadbeds, or 2 feet belowthe original ground or finished grade outside ofroadbeds, or 2 feet below the established limits ofany navigation channel.

Footing forms where their removal would endangerthe safety of cofferdams or other work.

486 HIGHWAY BRIDGES 3.2.3.4


Forms from enclosed cells where access is notprovided.

Deck forms in the cells of box girder bridges that donot interfere with the future installation of utilitiesshown on the plans.

3.3 COFFERDAMS AND SHORING

3.3.1 General

Cofferdams and shoring consist of those structuresused to temporarily hold the surrounding earth and waterout of excavations and to protect adjacent property and fa-cilities during construction of the permanent work.

Cofferdams shall be constructed to adequate depths,generally well below the bottom of the excavation, and toadequate heights to seal off all water. They shall be safelydesigned and constructed, and be made as watertight as isnecessary for the proper performance of the work whichmust be done inside them. In general, the interior dimen-sions of cofferdams shall be such as to give sufficientclearance for the construction of forms and the inspectionof their exteriors, and to permit pumping from outside theforms. Cofferdams which are tilted or moved laterallyduring the process of sinking shall be righted, reset, or en-larged so as to provide the necessary clearance. This shallbe solely at the expense of the Contractor.

When water cannot be controlled so that footing con-crete can be placed in the dry, a cofferdam shall be em-ployed, and a concrete seal conforming to the require-ments of Section 8, “Concrete Structures” placedunderwater below the elevation of the footing. When sucha seal is shown on the plans, the Engineer will determineif a cofferdam and seal is required, the depth of the seal tobe used, and the required cure time. Such determinationwill be based on conditions existing at the time of con-struction. When a concrete seal is not shown on the plans,the Contractor shall make these determinations, and shallbe fully responsible for the performance of the seal. Afterthe seal has cured, the cofferdam shall then be pumped outand the balance of the masonry placed in the dry. Whenweighted cofferdams are employed and the weight is uti-lized to partially overcome the hydrostatic pressure actingagainst the bottom of the foundation seal, special anchor-age such as dowels or keys shall be provided to transferthe entire weight of the cofferdam into the foundationseal. During the placing and curing of a foundation seal,the elevation of the water inside the cofferdam shall becontrolled to prevent any flow through the seal, and if thecofferdam is to remain in place, it shall be vented orported at or below low water level.

Shoring shall be adequate to support all loads imposedand shall comply with any applicable safety regulations.

3.3.2 Protection of Concrete

Cofferdams shall be constructed so as to protect greenconcrete against damage from a sudden rising of thestream and to prevent damage to the foundation by ero-sion. No struts or braces shall be used in cofferdams orshoring systems in such a way as to extend into or throughthe permanent work, without written permission from theEngineer.

3.3.3 Removal

Unless otherwise provided or approved, cofferdams,and shoring with all sheeting and bracing shall be removedafter the completion of the substructure, with care beingtaken not to disturb or otherwise injure the finished work.

3.4 TEMPORARY WATER CONTROL SYSTEMS

3.4.1 General

Temporary water control systems consist of dikes, by-pass channels, flumes and other surface water diversionworks, cut-off walls and pumping systems, includingwellpoint and deep well systems, used to prevent waterfrom entering excavations for structures.

3.4.2 Drawings

Working drawings for temporary water control sys-tems, when required, shall include details of the designand the equipment, operating procedures to be employed,and location of point or points of discharge. The designand operation shall conform to all applicable water pollu-tion control requirements.

3.4.3 Operations

Pumping from the interior of any foundation enclosureshall be done in such manner as to preclude the possibil-ity of the movement of water through any fresh concrete.No pumping will be permitted during the placing of con-crete or for a period of at least 24 hours thereafter, unlessit be done from a suitable sump separated from the con-crete work by a watertight wall or other effective meanssubject to approval of the Engineer.

Pumping to unwater a sealed cofferdam shall not com-mence until the seal has set sufficiently to withstand thehydrostatic pressure.

Pumping from wellpoints or deep wells shall be regu-lated so as to avoid damage by subsidence to adjacentproperty.



3.5 TEMPORARY BRIDGES

3.5.1 General

Temporary bridges include detour bridges for use bythe public, haul road bridges and other structures, such asconveyor bridges, used by the Contractor. Temporarybridges shall be constructed, maintained and removed ina manner that will not endanger the work or the public.

3.5.2 Detour Bridges

When a design is furnished by the Department, detourbridges shall be constructed and maintained to conform tosuch design or an approved alternative design. When per-mitted by the specifications, the Contractor may submit aproposed alternative design. Any alternative design mustbe equivalent in all respects to the design and details fur-nished by the Department and is subject to approval by theEngineer. The working drawings and design calculationsfor any alternative design must be signed by a RegisteredProfessional Engineer.

When a design is not furnished by the Department, theContractor shall prepare the design and furnish workingdrawings to the Engineer for approval. The design shallprovide the clearances, alignment, load capacity and otherdesign parameters specified or approved. The design shallconform to the Standard Specifications for HighwayBridges adopted by AASHTO. If design live loads are nototherwise specified, an HS II 15-44 loading shall be used.The working drawings and design calculations shall besigned by a Registered Professional Engineer.

3.5.3 Haul Bridges

When haul road bridges or other bridges which are notfor public use are proposed for construction over anyright-of-way which is open to the public or over any rail-road, working drawings showing complete design and de-

tails, including the maximum loads to be carried, shall besubmitted to the Engineer for approval. Such drawingsshall be signed by a Registered Professional Engineer.The design shall conform to AASHTO design standardswhen applicable or to other appropriate standards.

3.5.4 Maintenance

The maintenance of temporary bridges for whichworking drawings are required shall include their re-placement in case of partial or complete failure. The De-partment reserves the right, in case of the Contractor’sdelay or inadequate progress in making repairs and re-placement, to furnish such labor, materials, and supervi-sion of the work as may be necessary to restore the struc-ture for proper movement of traffic. The entire expense ofsuch restoration and repairs shall be considered a part ofthe cost of the temporary structure and where such ex-penditures are incurred by the Department, they shall becharged to the Contractor.


Unless otherwise provided, payment for temporaryworks shall be considered to be included in the paymentfor the various items of work for which they are used andno separate payment will be made therefore.

When an item for concrete seals for cofferdams is in-cluded in the bid schedule, such concrete will be mea-sured and paid for as provided in Section 8, “ConcreteStructures.”

When an item or items for temporary bridges, coffer-dams, shoring systems or water control systems is in-cluded in the bid schedule, payment will be the lump sumbid for each such structure or system which is listed on thebid schedule and which is constructed and removed in ac-cordance with the contract requirements. Such paymentincludes full compensation for all costs involved with thefurnishing of all materials and the construction, mainte-nance, and removal of such temporary works.



Section 4DRIVEN FOUNDATION PILES

4.1 DESCRIPTION

This work shall consist of furnishing and driving foun-dation piles of the type and dimensions designated on theplans or in the special provisions including cutting off orbuilding up foundation piles when required. This specifi-cation also covers providing test piles and performingloading tests. Piling shall conform to and be installed inaccordance with these specifications, and at the location,and to the elevation, penetration, and bearing capacityshown on the plans or as directed by the Engineer.

Any improperly driven, broken, or otherwise defectivepile shall be corrected to the satisfaction of the Engineerby removal and replacement, or the driving of an addi-tional pile, at no extra cost.

Except when test piles are required, the Contractorshall furnish the piles in accordance with the dimensionsshown on the plans or special provisions. When test pilesare required, the pile lengths shown on the plans are forestimating purposes only and the actual lengths to be fur-nished for production piles will be determined by the En-gineer after the test piles have been driven. The lengthsgiven in the Engineer’s order list will include only thelengths anticipated for use in the completed structure. TheContractor shall, without added compensation, increasethe lengths shown or ordered to provide for fresh headingand for such additional length as may be necessary to suitthe method of operation.

4.2 MATERIALS

4.2.1 Steel Piles

The structural steel used for foundation piling shallconform to the Specification for Structural Steel forBridges, AASHTO M 270 (ASTM A 709) Grades 36, 50,or 50W, or to the Specification for Piling for Use in Ma-rine Environment, ASTM A 690.

4.2.1.1 Painting

Unless otherwise provided, when steel piles or steelpile shells extend above the ground surface or water sur-

face they shall be protected by the paint system specifiedfor painting new steel in a high pollution or coastal envi-ronment as described in Section 13, “Painting.” This pro-tection shall extend from an elevation 2 feet below thewater or ground surface to the top of the exposed steel.

4.2.2 Timber Piles

Timber piles shall conform to the requirements of theSpecification for Wood Products, AASHTO M 168. Tim-ber piles shall be treated or untreated as indicated on theplans or in the special provisions. Preservative treatmentshall conform to the requirements of Section 17, “Preserv-ative Treatment of Wood.”

The method of storing and handling shall be such as toavoid injury to the piles. Special care shall be taken toavoid breaking the surface of treated piles. Canthooks,dogs, or pike-poles shall not be used. Cuts or breaks in thesurface of treated piling and bolt holes shall be treated asspecified in Article 16.3.3, “Treated Timber.”

4.2.3 Concrete Piles

Concrete piles shall consist of either precast concretepiles or cast-in-place concrete piles cast in steel shells.Portland cement concrete shall conform to the require-ments in Section 8, “Concrete Structures,” and unless an-other class is shown on the plans or specified, concreteshall be Class A. Reinforcing steel shall conform to the re-quirements of Section 9, “Reinforcing Steel,” and pre-stressing shall conform to the requirements of Section 10,“Prestressing.”

Steel shells for cast-in-place concrete piles shall be ofnot less than the thickness shown on the plans. The Con-tractor shall furnish shells of greater thickness if necessaryto provide sufficient strength and rigidity to permit dri-ving with the equipment selected for use without damage,and to prevent distortion caused by soil pressures or thedriving of adjacent piles. The shells shall also be water-tight to exclude water during the placing of concrete. Theshells may be cylindrical or tapered, step-tapered, or acombination of either, with cylindrical sections.

489


4.3 MANUFACTURE OF PILES

4.3.1 Precast Concrete Piles

4.3.1.1 Forms

Forms for precast concrete piles shall conform to thegeneral requirements for concrete form work as providedin Section 3, “Temporary Works.” Forms shall provide ac-cess for vibration and consolidation of the concrete.

4.3.1.2 Casting

Handling and placing of concrete shall conform to therequirements of Section 8, “Concrete Structures,” andthese specifications. Special care shall be taken to placethe concrete so as to produce satisfactory bond with thereinforcement and avoid the formation of “stone pockets,”honeycomb, or other such defects.

To secure uniformity, the concrete in each pile shall beplaced continuously and shall be compacted by vibratingor by other means acceptable to the Engineer. The formsshall be overfilled, the surplus concrete screeded off, andthe top surfaces finished to a uniform, even texture simi-lar to that produced by the forms.

4.3.1.3 Finish

Portions of piling exposed to view shall be finished inaccordance with the provisions governing the finishing ofconcrete columns. Other piling shall not be finished ex-cept as set forth above.

4.3.1.4 Curing and Protection

Concrete piles shall be cured as provided in Section 8, “Concrete Structures,” and these Specifications. Assoon as the piles have set sufficiently to avoid damage,they shall be removed from the forms and stacked in acuring pile separated from each other by wood-spacingblocks.

No pile shall be driven until at least 21 days aftercasting and, in cold weather, for a longer period asdetermined by the Engineer. Concrete piles for use in seawater or sulfate soils shall be cured for not less than 30 days before being used. Concrete shall be protectedfrom freezing until the compressive strength reaches atleast 0.8 fc�.

4.3.1.5 Prestressing

Prestressing of concrete piles shall conform to the pro-visions of Section 10, “Prestressing.”

4.3.1.5.1 Working Drawings

The Contractor shall submit two sets of workingdrawings to the Engineer at the job site for prestressedconcrete piles. Said drawings shall show the pile dimen-sions, materials, prestressing methods, tendon arrange-ment and prestressing forces proposed for use and, anyaddition or rearrangement of reinforcing steel from thatshown on the plans. Construction of the piles shall notbegin until the drawings have been approved by theEngineer.

4.3.1.6 Storage and Handling

Removal of forms, curing, storing, transporting, andhandling of precast concrete piles shall be done in such amanner as to avoid excessive bending stresses, cracking,spalling, or other injurious results.

Piles to be used in sea water or in sulfate soils shall behandled so as to avoid surface abrasions or other injuriesexposing the interior concrete.

4.3.2 Cast-in-Place Concrete Piles

4.3.2.1 Inspection of Metal Shells

At all times prior to the placing of concrete in the driv-en shells, the Contractor shall have available a suitablelight for the inspection of each shell throughout its entirelength.

4.3.2.2 Placing Concrete

No concrete shall be placed until all driving within a radius of 15 feet of the pile has been completed, or all driving within the above limits shall be discontinueduntil the concrete in the last pile cast has set at least 5 days.

Concrete for cast-in-place piles shall be dense and homogeneous. In lieu of the provisions concerningvibration of concrete as specified in Article 8.7.4, vibra-tion or rodding of concrete for cast-in-place piles will only be required to a depth of 5 feet below the groundsurface.

Concrete shall be placed for each pile in a singlecontinuous operation with the flow of concrete directeddown the center of the pile so as to consolidate theconcrete by impact. Accumulations of water in shells shallbe removed before the concrete is placed. After theconcrete has hardened, the top surface shall be cut back toremove laitance and to expose the aggregate as specifiedin Article 8.8.



4.4 DRIVING PILES

4.4.1 Pile Driving Equipment

Driving equipment that damages the piling shall not beused.

All pile driving equipment, including the pile drivinghammer, hammer cushion, drive head, pile cushion andother appurtenances to be furnished by the Contractorshall be approved in advance by the Engineer before anydriving can take place. Pursuant to obtaining this ap-proval, the Contractor shall submit, at least 2 weeks be-fore pile driving is to begin, a description of pile drivingequipment to the Engineer.

Whenever the bearing capacity of piles is specified tobe determined by Method B, “Wave Equation Analysis,”the Contractor shall also submit calculations, based on awave equation analysis, demonstrating that the piles canbe driven with reasonable effort to the ordered lengthswithout damage.

The following hammer efficiencies shall be used in awave equation analysis:

Hammer Type Efficiency in Percent

Single acting air/steam 67Double acting air/steam 50Diesel 72

In addition to the other requirements of these specifi-cations, the criteria which the Engineer will use to evalu-ate the driving equipment consists of both the requirednumber of hammer blows per inch and the pile stresses atthe required ultimate pile capacity. The required numberof hammer blows indicated by calculations at the requiredbearing capacity shall be between 3 and 10 per inch forthe driving equipment to be acceptable.

In addition, for the driving equipment to be acceptable,the pile stresses, which are indicated by the calculations,to be generated by the driving equipment shall not exceedthe values where pile damage impends. The point of im-pending damage in steel piles is defined herein as a com-pressive driving stress of 90% of the yield point of the pilematerial. For concrete piles, tensile stresses shall not ex-ceed 3 multiplied by the square root of the concrete com-pressive strength, fc�, plus the effective prestress value,i.e., (3�fc�� prestress), and compressive stresses shallnot exceed 85% of the compressive strength minus the ef-fective prestress value, i.e. (0.85 fc� � prestress). For tim-ber piles, the compressive driving stress shall not exceedthree times the allowable static design strength listed onthe plans. These criteria will be used in evaluating calcu-lated results to determine acceptability of the Contractor’sproposed driving system.

During pile driving operations, the Contractor shall usethe approved system. Any change in the driving systemwill only be considered after the Contractor has submittedrevised pile driving equipment data and calculations. TheContractor will be notified of the acceptance or rejectionof the driving system changes within 7 calendar days ofthe Engineer’s receipt of the requested change. The timerequired for submission, review, and approval of a reviseddriving system shall not constitute the basis for a contracttime extension to the Contractor.

Approval of pile driving equipment shall not relievethe Contractor of his responsibility to drive piles, free ofdamage, to the bearing and tip elevation shown on theplans or specified in the special provisions.

4.4.1.1 Hammers

4.4.1.1.1 General

Piles may be driven with a drop hammer, an air/steamhammer, or diesel hammer conforming to these specifica-tions.

Pile driving hammers, other than drop hammers, shallbe of the size needed to develop the energy required todrive piles at a penetration rate of not less than 0.10 inchper blow at the required bearing value.

4.4.1.1.2 Drop Hammers

Drop (gravity) hammers shall not be used for concretepiles or for piles whose design load capacity exceeds 30tons. When gravity hammers are permitted, the ram shallweigh not less than 2,000 pounds and the height of dropshall not exceed 15 feet. In no case shall the ram weightof gravity hammers be less than the combined weight ofthe drive cap and pile. All gravity hammers shall beequipped with hammer guides to insure concentric impacton the drive head or pile cushion.

4.4.1.1.3 Air Steam Hammers

The weight of the striking part of air/steam hammersused shall not be less than 1 ⁄3 the weight of pile and drivecap, and in no case shall the striking part weigh less than2,750 pounds. The plant and equipment furnished forair/steam hammers shall have sufficient capacity to main-tain, under working conditions, the pressure at the ham-mer specified by the manufacturer.

4.4.1.1.4 Diesel Hammers

Open-end (single acting) diesel hammers shall beequipped with a device to permit the Engineer to deter-mine hammer stroke at all times during pile driving oper-ations. Closed-end (double acting) diesel hammers shall

4.4 DIVISION II—CONSTRUCTION 491


be equipped with a bounce chamber pressure gauge, ingood working order, mounted near ground level so as tobe easily read by the Engineer. A correlation chart ofbounce chamber pressure and delivered hammer energyshall be provided by the Contractor.

4.4.1.1.5 Vibratory Hammers

Vibratory or other pile driving methods may be usedonly when specifically allowed by the Special Provisions orin writing by the Engineer. Except when pile lengths havebeen determined from load test piles, the bearing capacityof piles driven with vibratory hammers shall be verified byredriving the first pile driven in each group of 10 piles withan impact hammer of suitable energy to measure the pilecapacity before driving the remaining piles in the group.

4.4.1.1.6 Additional Equipment or Methods

In case the required penetration is not obtained by theuse of a hammer complying with the above minimum re-quirements, the Contractor may be required to provide ahammer of greater energy or, when permitted, resort tosupplemental methods such as jetting or preboring.

4.4.1.2 Driving Appurtenances

4.4.1.2.1 Hammer Cushion

All impact pile driving equipment except gravity ham-mers shall be equipped with a suitable thickness of ham-mer cushion material to prevent damage to the hammer orpile and to insure uniform driving behavior. Hammer cush-ions shall be made of durable, manufactured materials,which will retain uniform properties during driving. Wood,wire rope, and asbestos hammer cushions shall not beused. A striker plate shall be placed on the hammer cush-ion to insure uniform compression of the cushion material.The hammer cushion shall be inspected in the presence ofthe Engineer when beginning pile driving and after each100 hours of pile driving. The hammer cushion shall be re-placed by the Contractor before driving is permitted tocontinue whenever there is a reduction of hammer cushionthickness exceeding 25% of the original thickness.

4.4.1.2.2 Pile Drive Head

Piles driven with impact hammers shall be fitted withan adequate drive head to distribute the hammer blow tothe pile head. The drive head shall be axially aligned withthe hammer and the pile. The drive head shall be guidedby the leads and not be free-swinging. The drive headshall fit around the pile head in such a manner as to pre-vent transfer of torsional forces during driving whilemaintaining proper alignment of hammer and pile.

For steel and timber piling, the pile heads shall be cutsquarely and a drive head provided to hold the longitudi-nal axis of the pile in line with the axis of the hammer.

For precast concrete and prestressed concrete piles, thepile head shall be plane and perpendicular to the longitu-dinal axis of the pile to prevent eccentric impacts from thedrive head.

For special types of piles, appropriate driving heads,mandrels or other devices shall be provided so that thepiles may be driven without damage.

4.4.1.2.3 Pile Cushion

The heads of concrete piles shall be protected by a pilecushion when the nature of the driving is such as to un-duly injure them. When plywood is used, the minimumthickness placed on the pile head prior to driving shall notbe less than 4 inches. A new pile cushion shall be providedif, during driving, the cushion is either compressed morethan one-half the original thickness or begins to burn. The pile cushion dimensions shall be such as to distributethe blow of the hammer throughout the cross section ofthe pile.

4.4.1.2.4 Leads

Pile driving leads which support the pile and the ham-mer in proper positions throughout the driving operationshall be used. Leads shall be constructed in a manner thataffords freedom of movement of the hammer while main-taining alignment of the hammer and the pile to insureconcentric impact for each blow. The leads shall be of suf-ficient length to make the use of a follower unnecessaryand shall be so designed as to permit proper alignment ofbattered piles.

4.4.1.2.5 Followers

Followers shall only be used when approved in writingby the Engineer, or when specifically allowed in the spe-cial provisions. When a follower is permitted, in order toverify that adequate pile penetration is being attained todevelop the desired pile capacity, the first pile in each bentand every 10th pile driven thereafter shall be furnishedsufficiently long and shall be driven full length without afollower. The follower and pile shall be held and main-tained in equal and proper alignment during driving. Thefollower shall be of such material and dimensions to per-mit the piles to be driven to the length determined neces-sary from the driving of the full length piles. The final po-sition and alignment of the first two piles installed withfollowers in each substructure unit shall be verified to bein accordance with the location tolerances specified in Ar-ticle 4.4.3 before additional piles are installed.

492 HIGHWAY BRIDGES 4.4.1.1.4


4.4.1.2.6 Jets

Jetting shall only be permitted if approved in writing bythe Engineer or when specifically allowed in the specialprovisions. When jetting is not required, but approved afterthe Contractor’s request, the Contractor shall determinethe number of jets and the volume and pressure of water atthe jet nozzles necessary to freely erode the material adja-cent to the pile without affecting the lateral stability of thefinal in-place pile. The Contractor shall be responsible forall damage to the site caused by jetting operations. Whenjetting is specifically required in the special provisions, thejetting plant shall have sufficient capacity to deliver at alltimes a pressure equivalent to at least 100 pounds persquare inch at two 3 ⁄4-inch jet nozzles. In either case unlessotherwise indicated by the Engineer, jet pipes shall be re-moved when the pile tip is a minimum of 5 feet above pre-scribed tip elevation and the pile shall be driven to the re-quired bearing capacity with an impact hammer. Also, theContractor shall control, treat if necessary, and dispose ofall jet water in a manner satisfactory to the Engineer.

4.4.2 Preparation for Driving

4.4.2.1 Site Work

4.4.2.1.1 Excavation

In general, piles shall not be driven until after the ex-cavation is complete. Any material forced up between thepiles shall be removed to the correct elevation before con-crete for the foundation is placed.

4.4.2.1.2 Preboring to Facilitate Driving

When required by the special provisions, the Contrac-tor shall prebore holes at pile locations to the depths shownon the plans, specified in the special provisions, or allowedby the Engineer. Prebored holes shall be smaller than thediameter or diagonal of the pile cross section and sufficientto allow penetration of the pile to the specified depth. Ifsubsurface obstructions, such as boulders or rock layersare encountered, the hole diameter may be increased to theleast dimension which is adequate for pile installation. Anyvoid space remaining around the pile after completion ofdriving shall be filled with sand or other approved mater-ial. The use of spuds (a short strong driven member whichis removed to make a hole for inserting a pile), shall not bepermitted in lieu of preboring, unless specifically allowedby the special provisions or in writing by the Engineer.

4.4.2.1.3 Predrilled Holes in Embankments

Piles to be driven through newly constructed embank-ments shall be driven in holes drilled or spudded through

the embankment when the depth of the new embankmentis in excess of 5 feet. The hole shall have a diameter of notless than the greatest dimension of the pile cross sectionplus 6 inches. After driving the pile, the space around thepile shall be filled to ground surface with dry sand or peagravel. Material resulting from drilling holes shall be dis-posed of as approved by the Engineer.

4.4.2.2 Preparation of Piling

In addition to squaring up pile heads prior to driving,piles shall be further prepared for driving as describedbelow.

4.4.2.2.1 Collars

When timber piles are required to be driven to morethan 35 tons bearing or when driving conditions otherwiserequire it, collars, bands, or other devices shall be pro-vided to protect piles against splitting and brooming.

4.4.2.2.2 Pointing

Timber piles shall be pointed where soil conditions re-quire it. When necessary, the piles shall be shod withmetal shoes of a design satisfactory to the Engineer, thepoints of the piles being carefully shaped to secure aneven and uniform bearing on the shoes.

4.4.2.2.3 Pile Shoes and Lugs

Pile shoes used to protect all types of piles when harddriving is expected and pile lugs used to increase the bear-ing capacity of steel piles shall be of the types shown onthe plans and shall be used at the locations specified or or-dered by the Engineer. Steel pile shoes shall be fabricatedfrom cast steel conforming to ASTM A 27.

Such pile shoes or lugs used at the option of the Con-tractor shall be of a type approved by the Engineer.

4.4.3 Driving

Piles shall be driven to the minimum tip elevations andbearing capacity shown on the plans, specified in the spe-cial provisions or approved by the Engineer. Piles thatheave more than 1 ⁄4 inch upward during the driving of ad-jacent piles shall be redriven.

4.4.3.1 Driving of Test Piles

Test piles and piles for static load tests, when shown onthe plans, shall be furnished to the lengths ordered and driv-en at the locations and to the elevations directed by theEngineer before other piles in the area represented by thetest are ordered or driven. All test piles shall be driven

4.4.1.2.6 DIVISION II—CONSTRUCTION 493


with impact hammers unless specifically stated otherwisein the special provisions or on the plans. In general, the or-dered length of test piles will be greater than the estimatedlength of production piles in order to provide for variationin soil conditions. The driving equipment used for drivingtest piles shall be identical to that which the Contractorproposes to use on the production piling. Approval ofdriving equipment shall conform with the requirements ofthese Specifications. Unless otherwise permitted by theEngineer, the Contractor shall excavate the ground at eachtest pile to the elevation of the bottom of the footing be-fore the pile is driven.

Test piles shall be driven to a hammer blow count es-tablished by the Engineer at the estimated tip elevation.Test piles which do not attain the hammer blow countspecified above at a depth of 1 foot above the estimatedtip elevation shown on the plans shall be allowed to “setup” for a period of from 12 to 24 hours, as determined bythe Engineer, before being redriven. When possible, thehammer shall be warmed up before redriving begins byapplying at least 20 blows to another pile. If the specifiedhammer blow count is not attained on redriving, the En-gineer may direct the Contractor to drive a portion or allof the remaining test pile length and repeat the “set up”—redrive procedure. When ordered by the Engineer, testpiles driven to plan grade and not having the hammerblow count required shall be spliced and driven until therequired bearing is obtained.

4.4.3.2 Accuracy of Driving

Piles shall be driven with a variation of not more than1 ⁄4 inch per foot from the vertical or from the batter shownon the plans, except that piles for trestle bents shall be sodriven that the cap may be placed in its proper locationwithout inducing excessive stresses in the piles. Founda-tion piles shall not be out of the position shown on the planby more than 1 ⁄4 of their diameter or 6 inches, whicheveris greater, after driving. Any increase in footing dimen-sions or reinforcing due to out-of-position piles shall be atthe Contractor’s expense.

4.4.4 Determination of Bearing Capacity

4.4.4.1 General

Piles shall be driven to the bearing capacity shown onthe plans or specified in the special provisions. The bear-ing capacity of piles will be determined by the Engineeras provided in the special provisions using one or a com-bination of the following methods. Method A, EmpiricalPile Formula, will be used in the absence of special pro-visions to the contrary.

4.4.4.2 Method A—Empirical Pile Formulas

When not driven to practical refusal, the design bearing capacities of piles will be determined by anempirical pile formula. Unless otherwise provided in thespecial provisions, the following formulas (ENR) will beused.

where:

P � bearing capacity in poundsW � weight, in pounds, of striking parts of the ham-

merH � height of fall in feetE � energy produced by the hammer per blow in foot/

pounds. Value based on actual hammer stroke orbounce chamber pressure observed (double act-ing diesel hammer)

S � the average penetration in inches per blow for the last 5 to 10 blows for gravity hammers and the last 10 to 20 blows for all other ham-mers.

The above formulas are applicable only when:

The hammer has a free fall (gravity and single-actinghammers only).

The head of the pile is not broomed, crushed, or other-wise damaged.

The penetration is reasonably quick and uniform.There is no appreciable rebound of the hammer.A follower is not used.

The penetration per blow may be measured either dur-ing initial driving or by redriving with a warm hammeroperated at full energy after a pile set period, as deter-mined by the Engineer.

In case water jets are used in connection with the driv-ing, the bearing capacity shall be determined by the aboveformulas from the results of driving after the jets havebeen withdrawn.

4.4.4.3 Method B—Wave Equation Analysis

When specified, ultimate bearing capacity of a pile willbe determined by using a wave equation analysis. Soil,pile, and driving equipment properties to be used in thisanalysis will be as shown on the plans, as specified in the

PWH

S

PE

S

=+

=+

2

1 02

0 1

.

.

for drop (gravity) hammers (4 -1)

for all other hammers (4 - 2)



special provisions or as determined by the Engineer usingdata obtained from the Contractor, test borings and, whenused, dynamic pile tests (Method C).

The design bearing capacity of a pile shall be 0.364 ofthe calculated ultimate bearing capacity as determinedfrom a wave equation analysis alone. When the ultimatebearing capacity is determined from a wave equationanalysis that has been calibrated to the results of a dy-namic pile test, the design bearing capacity shall be 0.444of the calculated ultimate bearing capacity.

4.4.4.4 Method C—Dynamic Load Tests

Dynamic measurements will be taken by the Engineerduring the driving of piles designated as dynamic load testpiles. The ultimate capacity of the pile will be determinedwith the use of pile analyzer instruments.

Prior to placement in the leads, the Contractor shallmake each designated concrete and/or timber pile avail-able for taking of wave speed measurements and shallpredrill the required instrument attachment holes. Predriv-ing wave speed measurements will not be required forsteel piles. When wave speed measurements are made, thepiling shall be supported off the ground in a horizontal po-sition and not in contact with other piling. The Engineerwill furnish the equipment, materials, and labor necessaryfor drilling holes in the piles for mounting the instru-ments.

The Contractor shall either attach the instruments tothe pile after the pile is placed in the leads, or provide theEngineer reasonable means of access to the pile for at-taching instruments after the pile is placed in the leads. Aplatform with minimum size of 4 � 4 feet (16 square feet)designed to be raised to the top of the pile while the pileis located in the leads shall be provided by the Contractor.

The Contractor shall furnish electric power for the dy-namic test equipment. The power supply at the outlet shallbe 10 amp, 115 volt, 55-60 cycle, A.C. only. Field gener-ators used as the power source shall be equipped withfunctioning meters for monitoring voltage and frequencylevels.

The Contractor shall furnish a shelter to protect thedynamic test equipment from the elements. The sheltershall have a minimum floor size of 8 � 8 feet (64 squarefeet) and minimum roof height of 7 feet. The inside tem-perature of the shelter shall be maintained above 45°.The shelter shall be located within 50 feet of the test lo-cation.

The Contractor shall drive the pile to the depth atwhich the dynamic test equipment indicates that the de-sign bearing capacity shown in the contract plans has beenachieved, unless directed otherwise by the Engineer. If di-rected by the Engineer, the Contractor shall reduce the driv-

ing energy transmitted to the pile by using additionalcushions or reducing the energy output of the hammer inorder to maintain acceptable stresses in the piles. If non-axial driving is indicated by dynamic test equipment mea-surements, the Contractor shall immediately realign thedriving system.

When directed by the Engineer, the Contractor shallwait up to 24 hours and, after the instruments are reat-tached, redrive the dynamic load test pile. The hammershall be warmed up before redrive begins by applying atleast 20 blows to another pile. The maximum amount ofpenetration required during redrive shall be 6 inches or themaximum total number of hammer blows required will be50, whichever occurs first. After redriving, the Engineerwill either provide the cut-off elevation or specify addi-tional pile penetration and testing.

4.4.4.5 Method D—Static Load Tests

Load tests shall be performed by procedures set forth in ASTM D 1143 using the quick load compressiontest method except that the test shall be taken to plungingfailure or three times design load or 1,000 tons which-ever occurs first. Testing equipment and measuringsystems shall conform to ASTM D 1143. The Contractorshall submit to the Engineer for approval, detailed plans,prepared by a licensed professional engineer, of theproposed loading apparatus. The apparatus shall beconstructed to allow the various increments of the load to be placed gradually without causing vibration to the test pile. When the approved method requires the use oftension (anchor) piles which will later be used as perma-nent piles in the work, such tension piles shall be of thesame type and diameter as the production piles and shallbe driven in the location of permanent piles when feasible.

The design bearing capacity shall be defined as 50% ofthe failure load.

The failure load of a pile tested under axial compres-sive load is that load which produces a settlement at fail-ure of the pile head equal to:

Sf � S � (0.15 � 0.008D)

where:

Sf � Settlement at failure in inchesD � Pile diameter or width in inchesS � Elastic deformation of total unsupported pile

length in inches

The top elevation of the test pile shall be determinedimmediately after driving and again just before load test-



ing to check for heave. Any pile which heaves more than1⁄ 4 inch shall be redriven or jacked to the original elevationprior to testing. Unless otherwise specified in the contract,a minimum 3-day waiting period shall be observed be-tween the driving of any anchor piles or the load test pileand the commencement of the load test.

4.4.5 Splicing of Piles

4.4.5.1 Steel Piles

Full-length piles shall be used where practicable. Ifsplicing is permitted, the method of splicing shall be asshown on the plans or as approved by the Engineer. Thearc method of welding shall be preferred when splicingsteel piles. Welding shall only be performed by certifiedwelders.

4.4.5.2 Concrete Piles

Concrete piles shall not be spliced, other than to pro-duce short extensions as permitted herein, unless specifi-cally allowed by the plans, the special provisions, or bythe Engineer in writing.

Short extensions or “build-ups” may be added to thetops of reinforced concrete piles to correct for unantici-pated events. After the driving is completed, the concreteat the end of the pile shall be cut away, leaving the rein-forcing steel exposed for a length of 40 diameters. Thefinal cut of the concrete shall be perpendicular to the axisof the pile. Reinforcement similar to that used in the pileshall be securely fastened to the projecting steel and thenecessary form work shall be placed, care being taken toprevent leakage along the pile. The concrete shall be ofnot less than the quality used in the pile. Just prior to plac-ing concrete, the top of the pile shall be thoroughlyflushed with water, allowed to dry, then covered with athin coating of neat cement, mortar, or other suitablebonding material. The forms shall remain in place not lessthan 7 days and shall then be carefully removed and theentire exposed surface of the pile finished as previouslyspecified.

4.4.5.3 Timber Piles

Timber piles shall not be spliced unless specifically al-lowed by the plans, special provisions, or by the Engineerin writing.

4.4.6 Defective Piles

The procedure incident to the driving of piles shall notsubject them to excessive and undue abuse producing

crushing and spalling of the concrete, injurious splitting,splintering and brooming of the wood, or excessive defor-mation of the steel. Manipulation of piles to force theminto proper position, considered by the Engineer to be ex-cessive, will not be permitted. Any pile damaged by rea-son of internal defects or by improper driving or driven outof its proper location or driven below the butt elevationfixed by the plans or by the Engineer shall be corrected atthe Contractor’s expense by one of the following methodsapproved by the Engineer for the pile in question:

The pile shall be withdrawn and replaced by a newand, if necessary, a longer pile.

A second pile shall be driven adjacent to the defec-tive or low pile.

The pile shall be spliced or built up as otherwiseprovided herein or a sufficient portion of the foot-ing extended to properly embed the pile. All pilespushed up by the driving of adjacent piles or by anyother cause shall be driven down again.

All such remedial materials and work shall befurnished at the Contractor’s expense.

4.4.7 Pile Cut-off

4.4.7.1 General

All piles shall be cutoff to a true plane at the elevationsrequired and anchored to the structure, as shown on theplans.

All cutoff lengths of piling shall remain the property ofthe Contractor and shall be properly disposed of.

4.4.7.2 Timber Piles

Timber piles which support timber caps or grillageshall be sawed to conform to the plane of the bottom ofthe superimposed structure. In general, the length of pileabove the elevation of cutoff shall be sufficient to permitthe complete removal of all material injured by driving,but piles driven to very nearly the cutoff elevation shall becarefully adzed or otherwise freed from all “broomed,”splintered, or otherwise injured material.

Immediately after making final cutoff on treated tim-ber foundation piles, the cut area shall be given two lib-eral applications of preservative followed by a heavy ap-plication of coal-tar roofing cement or other approvedsealer. Treated timber piles which will have the cutoffexposed in the structure shall have the cut area treatedwith three coats of a compatible preservative materialmeeting the requirements of AWPA Standard M4. A min-imum time period of 2 hours shall elapse between eachapplication.




4.5.1 Method of Measurement

4.5.1.1 Timber, Steel, and Concrete Piles

4.5.1.1.1 Piles Furnished

The quantities of each type of pile to be paid for willbe the sum of the lengths in feet of the piles, of the typesand lengths indicated on the plans or ordered in writing bythe Engineer, furnished in compliance with the materialrequirements of these specifications and stockpiled or, inthe case of driven cast-in-place concrete piles, installed ingood condition at the site of the work by the Contractor,and accepted by the Engineer. The footage of piles, in-cluding test piles, furnished by the Contractor to replacepiles which were previously accepted by the Engineer, butwere subsequently damaged prior to completion of thecontract will not be included.

When extensions of piles are necessary, the extensionlength ordered in writing by the Engineer will be includedin the linear footage of piling furnished.

4.5.1.1.2 Piles Driven

The quantities of driven piles of each type to be paidfor will be the number of acceptable piles of each type thatwere driven.

Preboring, jetting, or other methods used for facil-itating pile driving procedures when either required or permitted will not be measured, and payment will beconsidered included in the unit price paid for the PilesDriven.

4.5.1.2 Pile Splices, Pile Shoes, and Pile Lugs

When pile splices, protective pile tip shoes or soil shearlugs are shown on the plans, the number of pile splices,shoes, or lugs measured for payment will be those shownon the plans, or ordered in writing by the Engineer, andactually installed on piles used in the work. No paymentwill be made for splices, shoes, or lugs used at the optionof the Contractor. When not shown on the plans or speci-fied to be used, pile splices, shoes, or lugs ordered by theEngineer will be paid for as extra work.

4.5.1.3 Load Tests

The quantity of load tests to be paid for will be thenumber of load tests completed and accepted, except that

load tests made at the option of the Contractor will not beincluded in the quantity measured for payment.

Anchor and test piles for load tests, whether incorpo-rated into the permanent structure or not, will be measuredas provided for Piles Furnished and Piles Driven and willbe paid for under the appropriate pay item.

4.5.2 Basis of Payment

The quantities, determined as provided, will be paid forat the contract price per unit of measurement, respectively,for each of the general pay items listed below for each sizeand type of pile shown in the bid schedule.

Pay Item Pay Unit

Piles, Furnished Linear FootPiles, Driven EachTest Piles, Furnished Linear FootTest Piles, Driven EachPile Load Test (Static) EachPile Load Test (Dynamic) EachSplices EachPile Shoes EachPile Lugs Each

Payment for furnishing piles includes full compensa-tion for all costs involved in the furnishing and deliveryof all piles, including steel shells for cast-in-place drivenpiles, to the project site and all costs involved in the fur-nishing and placing of concrete and reinforcing steel forcast-in-place concrete piles.

Payment for driving piles includes full compensationfor all costs involved in the actual driving and cutting offof piles and pile shells, and for all costs for which com-pensation is not provided for under other pay items in-volved with the furnishing of labor, equipment, and mate-rials used to construct the piles as shown on the plans andas specified or ordered. When mobilization of plant andequipment for the project is not paid for separately, pay-ment for driving piles also includes full compensation forthe cost of mobilization of all equipment needed for thehandling and driving piles after the piles have been deliv-ered to the project site.

Payment for load tests includes full compensation forproviding labor, equipment, and materials needed to per-form the load tests as specified.

Payment under the appropriate pay items for pilesplices, shoes, and lugs includes full compensation for allcosts involved with furnishing all materials and perform-ing the work involved with attaching or installing splices,shoes, or lugs to the piles.



Section 5DRILLED PILES AND SHAFTS

5.1 DESCRIPTION

This work shall consist of constructing drilled foun-dation shafts, with or without bell footings, including theplacing of reinforcing steel and concrete all in accor-dance with the plans, these specifications and the specialprovisions.

5.2 SUBMITTALS

5.2.1 Contractor Qualifications (Recommendedwhere permitted by state law)

(a) The Contractor shall have a minimum of 3 yearsexperience in constructing shaft foundations of similarsize, depth and site conditions within the past 5 years.Prior to shaft construction the Contractor shall submitwritten documentation of the three years experience tothe Engineer for verification and acceptance. The sub-mittal shall include at least three projects on which theContractor has previously been engaged in shaft con-struction with satisfactory results. A brief descriptionof each project and the owner’s contact person’s nameand current phone number shall be included for eachproject listed.(b) On-site supervisors shall have a minimum 2 yearsexperience in construction of shaft foundations, anddrill operators shall have a minimum 1 year experi-ence. Prior to the start of work, the Contractor shallsubmit a list identifying the on-site supervisors anddrill operators who will be assigned on the project. The list shall contain a summary of each individual’sexperience.(c) The Engineer will approve or reject the Contrac-tor’s qualifications and field personnel within 10 work-ing days after receipt of the submission. Work shall notbe started on any shaft until the Contractor’s qualifica-tions are approved by the Engineer. The Engineer maysuspend the shaft construction if the Contractor substi-tutes unqualified personnel. The Contractor shall befully liable for the additional costs resulting from thesuspension of work, and no adjustments in contract

time resulting from the suspension of work will be allowed.(d) A shaft preconstruction conference will be held with the Contractor and Sub-Contractor (if applicable) prior to the start of shaft construction to discuss construction and inspection procedures. This conference will be scheduled by the Engineerafter the Contractor’s submittals are approved by theEngineer.


When required by the special provisions, at least fourweeks before work on shafts is to begin, the Contractorshall submit to the Engineer for review and approval, aninstallation plan for the construction of drilled shafts. Thesubmittal shall include the following:

(a) List of proposed equipment to be used includingcranes, drills, augers, bailing buckets, final cleaningequipment, desanding equipment, slurry pumps, sam-pling equipment, tremies or concrete pumps, casing(including: casing dimensions, material and splice de-tails), etc.(b) Details of overall construction operation sequenceand the sequence of shaft construction in bents orgroups.(c) Details of shaft excavation methods, and final shaftdimensions.(d) When slurry is required, details of the method pro-posed to mix, circulate and desand slurry and disposalof slurry.(e) Details of methods to clean the shaft excavation,including the bottom of the shaft.(f) Details of reinforcement placement including sup-port and centralization methods.(g) Details of concrete placement, curing and protec-tion, that demonstrates contractors ability to performconcrete placement in the required time.(h) Other information shown on the plans or requestedby the Engineer.(i) Concrete mixes, and mitigation of possible slumploss during placement at the site.

499


The Contractor shall not start the construction ofdrilled shafts for which Contractor qualifications andworking drawings are required until such submittals havebeen approved by the Engineer. Such approval will not re-lieve the Contractor of responsibility for results obtainedby use of these submittals or any other responsibilitiesunder the contract.

5.3 MATERIALS

5.3.1 Concrete

Concrete shall conform to the requirements of Section8. The concrete shall be Class A unless otherwise specified.

NOTE: The concrete mix for drilled shafts shall befluid, consolidate under self-weight, be resistant to seg-regation, and have a set time that will assure that fluid-ity is maintained throughout the shaft concrete place-ment, and removal of temporary casing. The time forinitial set of the shaft concrete should generally not ex-ceed 12 hours.

5.3.2 Reinforcing Steel

Reinforcing steel shall conform to the requirements ofSection 9, “Reinforcing Steel.”

5.3.3 Casings

Casings which are required to be incorporated as partof the permanent work shall conform to the requirementsof Section 11, “Steel Structures.” Steel shall be AASHTOM 183 (ASTM A 36), AASHTO M 270 (ASTM A 709)Grade 36, or ASTM A 252, Grade 2 or 3 unless otherwisespecified.

5.4 CONSTRUCTION

5.4.1 Protection of Existing Structures

All precautions shall be taken to prevent damage to ex-isting structures and utilities. These measures shall in-clude but are not limited to, selecting construction meth-ods and procedures that will prevent excessive caving ofthe shaft excavation, monitoring, and controlling the vi-brations from the driving of casing or sheeting, drilling ofthe shaft or from blasting, if permitted.

5.4.2 Construction Sequence

Where drilled shafts are to be installed in conjunctionwith embankment placement, they shall be constructedafter the placement of the fill and completion of any speci-fied settlement periods unless shown otherwise in the plans.

5.4.3 General Methods and Equipment

Excavations required for shafts and bell footings shallbe constructed to the dimensions and elevations shownon the plans. The methods and equipment used shall besuitable for the intended purpose and materials encoun-tered. Generally either the dry method, wet method, tem-porary casing method, or permanent casing method willbe used as necessary to produce sound, durable concretefoundation shafts free of defects. The permanent casingmethod shall be used only when required by the plans orauthorized by the Engineer. When a particular method of construction is required on the plans, that methodshall be used. If no particular method is specified for use, the Contractor shall select and use the method, asdetermined by site conditions, subject to approval of the Engineer, that is needed to properly accomplish the work.

The excavation shall be completed in a continuousoperation. If the excavation operation is stopped, theshaft cavity shall be protected by installation of a safetycover. It shall be the Contractor’s responsibility to en-sure the safety of the shaft excavation, surrounding soiland the stability of the side walls. A temporary casing,slurry or other methods approved by the Engineer shallbe used if necessary to ensure such safety and stability.Excavations shall not be left open overnight unless casedfull depth.

The Contractor shall use appropriate means such as acleanout bucket or air lift to clean the bottom of the excavation of all shafts. When unexpected obstructionsare encountered, the Contractor shall notify the Engineerpromptly. The removal of such obstructions, and the construction of excavation shall be as directed by the Engineer.

5.4.4 Dry Construction Method

The dry construction method shall be used only at siteswhere the groundwater table and site conditions are suit-able to permit construction of the shaft in a relatively dryexcavation, and where the sides and bottom of the shaftremain stable without any caving, sloughing or swellingand may be visually inspected prior to placing the con-crete. The dry method consists of drilling the shaft exca-vation, removing accumulated water and loose materialfrom the excavation, and placing the shaft concrete in arelatively dry excavation.

5.4.5 Wet Construction Method

The wet construction method shall be used at siteswhere a dry excavation cannot be maintained for place-ment of the shaft concrete. This method consists of using



water or mineral slurry to contain seepage, groundwatermovement, and to maintain stability of the hole perimeterwhile advancing the excavation to final depth, placing thereinforcing cage and shaft concrete. This procedure mayrequire desanding and cleaning the slurry; final cleaningof the excavation by means of a bailing bucket, air lift,submersible pump, cleanout bucket or other devices; andrequires placing the shaft concrete with a tremie. Tempo-rary surface casings shall be provided to aid shaft align-ment and position, and to prevent sloughing of the top ofthe shaft excavation, unless it is demonstrated to the sat-isfaction of the Engineer that the surface casing is not re-quired. Surface casing is defined as the amount of casingrequired from the ground surface to a point in the shaft ex-cavation where sloughing of the surrounding soil does notoccur.

5.4.6 Temporary Casing Construction Method

The temporary casing construction method shall beused at all sites where the stability of the excavated holeand/or the effects of groundwater cannot be controlled byother means.

Temporary casing may be installed by driving or vibra-tory procedures in advance of excavation to the lower limits of the caving material.

Temporary casings shall be removed while the con-crete remains workable (i.e., a slump of 4 inches orgreater). As the casing is being withdrawn, a 5 foot mini-mum head of fresh concrete in the casing shall be main-tained so that all the fluid trapped behind the casing is dis-placed upward without contaminating the shaft concrete.The required minimum concrete head may have to be in-creased to counteract groundwater head outside the cas-ing. Movement of the casing by rotating, exerting down-ward pressure and tapping to facilitate extraction orextraction with a vibratory hammer will be permitted.Casing extraction shall be at a slow, uniform rate with thepull in line with the shaft axis.

5.4.7 Permanent Casing Construction Method

The permanent casing construction method shall beused only when required by the plans. This method gen-erally consists of driving or drilling a casing to a pre-scribed depth before excavation begins. If full penetrationcannot be attained, the Contractor may either excavatematerial within the embedded portion of the casing or ex-cavate a pilot hole ahead of the casing until the casingreaches the desired penetration. The pilot hole shall be nolarger than one-half the diameter of the shaft and shall becentered in the shaft. Overreaming to the outside diame-ter of the casing shall not be performed unless specificallystated in the Plans or Special Provisions.

The casing shall be continuous between the elevationsshown on the plans. Unless shown on the plans, the use oftemporary casing in lieu of or in addition to the permanentcasing shall not be used.

After the installation of the casing and the excavationof the shaft is complete, the reinforcing steel shall beplaced, followed by the placement of the shaft concrete.After the permanent casing has been filled with concrete,any voids between the shaft excavation and the casingshall be pressure grouted with cement grout. The methodof pressure grouting the voids shall be submitted to theEngineer for approval.

NOTE: Pressure grouting is required to assure contact(bearing) between the casing and any surrounding soillayer that is utilized for lateral support.

5.4.8 Alternative Construction Methods

The Contractor may propose alternative methods toprevent caving and control ground water. Such proposals,accompanied by supporting technical data, shall be sub-mitted in accordance with Article 5.2, and are subject tothe approval of the Engineer.

5.4.9 Excavations

The bottom elevation of the drilled shaft shown on theplans may be adjusted during construction if the Engineerdetermines that the foundation material encountered dur-ing excavation is unsuitable or differs from that antici-pated in the design of the drilled shaft.

When specified or shown in the plans, the Contractorshall take soil samples or rock cores to determine the char-acter of the material directly below the shaft excavation.The Engineer will inspect the samples or cores and deter-mine the final depth of required shaft excavation.

Excavated materials which are removed from the shaftexcavation and any drilled fluids used shall be disposed ofin accordance with the special provisions, and in compli-ance with federal and state laws.

When bell footings are shown in the plans they shall beexcavated to form a bearing area of the size and shapeshown.

5.4.10 Casings

Casings shall be metal, smooth, clean, watertight, andof ample strength to withstand both handling and drivingstresses and the pressure of both concrete and the sur-rounding earth materials. The outside diameter of casingshall not be less than the specified diameter of the shaft.The inside diameter of the casing shall not be greater thanthe specified diameter of the shaft plus 6 inches unlessotherwise approved by the Engineer. Where the minimum



thickness of the casing is specified in the Plans, it is spec-ified to satisfy structural design requirements only. TheContractor shall increase the casing thickness as neces-sary to satisfy the casing strength requirements for han-dling and driving stresses.

Temporary casings may be corrugated and nonwater-tight if conditions permit.

5.4.11 Slurry

Slurry used in the drilling process shall be a mineralslurry. The slurry shall have both a mineral grain size thatwill remain in suspension and sufficient viscosity and gelcharacteristics to transport excavated material to a suitablescreening system. The percentage and specific gravity of thematerial used to make the suspension shall be sufficient tomaintain the stability of the excavation and to allow properconcrete placement. The level of the slurry shall be main-tained at a height sufficient to prevent caving of the hole.

The mineral slurry shall be premixed thoroughly withclean fresh water and adequate time allotted for hydrationprior to introduction into the shaft excavation. Adequateslurry tanks will be required when specified. No excavatedslurry pits will be allowed when slurry tanks are required onthe project without written permission of the Engineer. Ad-equate desanding equipment will be required when speci-fied. Steps shall be taken as necessary to prevent the slurryfrom “setting up” in the shaft excavation, such as, agitation,circulation, and adjusting the properties of the slurry.

Control tests using suitable apparatus shall be carriedout by the Contractor on the mineral slurry to determinedensity, viscosity, and pH. An acceptable range of valuesfor those physical properties is shown in the followingtable:

Range of Values (at 68°F)

Time of Time ofProperty Slurry Concreting Test(Units) Introduction (In Hole) Method

Density 64.3 to 64.3 to Density(pcf) 69.1 75.0 Balance

Viscosity(seconds 28 to 45 28 to 45 Marshper quart) Cone

pH 8 to 11 8 to 11 pH paper ormeter

Notes

(a) Increase density values by 2 pcf in salt water.(b) If desanding is required; sand content shall not ex-ceed 4% (by volume) at any point in the shaft excava-tion as determined by the American Petroleum Institutesand content test.

Tests to determine density, viscosity, and pH valuesshall be done before or during the shaft excavation to es-tablish a consistent working pattern.

Prior to placing shaft concrete, the Contractor shall usean approved slurry sampling tool to take slurry samplesfrom the bottom and at midheight of the shaft. Any heav-ily contaminated slurry that has accumulated at the bot-tom of the shaft shall be eliminated. The mineral slurryshall be within specification requirements immediatelybefore shaft concrete placement.

5.4.12 Excavation Inspection

The Contractor shall provide equipment for checkingthe dimensions and alignment of each shaft excavation.The dimensions and alignment shall be determined by theContractor under the direction of the Engineer. Final shaftdepth shall be measured after final cleaning.

No more than 1 ⁄2 inch of loose or disturbed materialshall be present at the bottom of the shaft just prior to plac-ing the concrete for end bearing shafts. No more than 2inches of loose or disturbed material shall be present forside friction shafts. End bearing shafts shall be assumedunless otherwise noted in the Plans. The excavated shaftshall have the approval of the Engineer prior to proceed-ing with construction.

5.4.13 Reinforcing Steel Cage Construction andPlacement

The reinforcing steel cage consisting of the steel shownon the plans plus cage stiffener bars, spacers, centralizers,and other necessary appurtenance shall be completely as-sembled and placed as a unit immediately after the shaft ex-cavation is inspected and accepted and prior to shaft con-crete placement. The reinforcing cage shall be rigidly bracedto retain its configuration during handling and construction.Individual or loose bars shall not be used. The Contractorshall show bracing and any extra reinforcing steel requiredfor fabrication of the cage on the shop drawings.

The reinforcement shall be carefully positioned and se-curely fastened to provide the minimum clearances listedbelow, and to ensure that no displacement of the reinforc-ing steel bars occurs during placement of the concrete.

Place bars as shown in the contract plans with concretecover as shown in the table below:

Concrete Cover

Shaft Casing CasingDiameter Uncased Remains Withdrawn

2�0� or less 3� 3� 4�3�0� 3� 3� 4�4�0� 4� 4� 4�5�0� or larger 6� 6� 6�



Rolling spacers for reinforcing steel shall be used tominimize disturbance of the side walls of the shaft and tofacilitate removal of the casing during concrete placement.

Concrete spacers or other approved noncorrosive spac-ing devices shall be used at sufficient intervals not exceed-ing 5 feet along the shaft to insure concentric location of thecage within the shaft excavation. When the size of the lon-gitudinal reinforcing steel exceeds one inch diameter, themaximum spacing of the spacing devices may be increasedto 10 feet (maximum). Approved noncorrosive bottom sup-ports shall be provided for the rebar cage to assure that thereinforcing is the proper distance above the base.

Other types of spacers may be used if approved by theEngineer. The Contractor shall submit details of the pro-posed reinforcing cage spacers along with the shop draw-ings. Shaft excavation shall not be started until the Con-tractor has received approval from the Engineer for theContractor-proposed spacers.

5.4.14 Concrete Placement, Curing, and Protection

Concrete placement shall commence immediately aftercompletion of excavation, inspection and setting of the re-inforcing cage, and shall continue in one operation, to thetop of the shaft, or to a construction joint identified on theplans. An unforeseen stoppage of work may require a hor-izontal construction joint during the shaft construction.For this reason, an emergency construction joint methodshall be submitted to the Engineer for approval prior tostarting shaft construction.

Concrete to be placed in water or slurry shall be placedthrough a tremie using methods specified in Article 8.7.5,“Underwater Placement.” Before placing any new con-crete against concrete deposited in water, the Contractorshall remove all scum, laitance, loose gravel and sedimenton the upper surface of the concrete deposited in water andchip off any high spots on the upper surface of the existingconcrete that would prevent any subsequent shaft rein-forcing from being placed in the position required by thePlans.

Concrete to be placed in dry shafts shall be placed andconsolidated as specified in Article 4.3.2, “Cast-in-PlaceConcrete Piles,” and these Specifications.

For shafts less than 8 feet in diameter, the elapsed timefrom the beginning of concrete placement in the shaft tothe completion of placement shall not exceed 2 hours un-less a shaft concrete retarder is approved by the Engineer.For shafts 8 feet and greater in diameter, the concrete plac-ing rate shall be not less than 30 feet of shaft height pereach 2-hour period providing a 4 inch minimum slump ismaintained throughout the concrete placement based ontests of a trial mix. The concrete mix shall be of such de-

sign that the concrete remains in workable plastic statethroughout the 2-hour placement limit.

When the top of shaft elevation is above ground, theportion of the shaft above ground shall be formed with a re-movable form or with a permanent casing, when specified.

The shaft concrete shall be vibrated or rodded to adepth of 5 feet below the ground surface except where softuncased soil or slurry remaining in the excavation willpossibly mix with the concrete.

After placement, the temporarily exposed surfaces ofthe shaft concrete shall be cured in accordance with theprovisions in Article 8.11, “Curing Concrete.”

For at least 48 hours after shaft concrete has beenplaced, no construction operations that would cause soilmovement adjacent to the shaft, other than mild vibration,shall not be conducted. Mild vibration is defined as oper-ation of light construction equipment adjacent to the shaft.

Portions of drilled shafts exposed to a body of watershall be protected from the action of water by leaving theforms in place for a minimum of seven days after concreteplacement or until the shaft concrete reaches a minimumstrength of 2500 psi, whichever occurs first.

5.4.15 Test Shafts and Bells

Test shafts shall be constructed when required in the con-tract. The construction of test shafts will be used to deter-mine if the methods, equipment, and procedures used by theContractor are sufficient to produce a shaft excavationwhich meets the requirements of the plans and specifica-tions. Production shaft construction shall not be started untilthe required test shaft(s) has been successfully completed.

The Contractor shall revise his methods and equipmentas necessary at any time during the construction of the testshaft hole to satisfactorily complete the excavation.

The location of the test shaft shall be as shown on theplans, or as directed by the Engineer. The diameter anddepth of the test shaft excavation shall be the same diam-eter and depth as the production drilled shafts shown on theplans. The test shaft holes shall be filled with concrete inthe same manner that production shafts will be constructedunless a different backfill material is shown on the plans.

When the Contractor fails to satisfactorily demonstratethe adequacy of his methods, procedures or equipment,additional test shafts shall be provided at no additionalcost to the Department, until a successful test shaft has been constructed in accordance with the Engineer-approved construction methods.

When shown on the plans, the reaming of bells at spec-ified test shaft holes will be required to establish the fea-sibility of belling in a specific soil strata.

5.4.16 Construction Tolerances

The following construction tolerances shall be main-tained in constructing drilled shafts.



(a) Shafts shall be constructed so that the center at thetop of the shaft is within the following tolerances:

Shaft Diameter Tolerance

2�-0� or less 3�3�-0� 31 �2�4�-0� 4�

5�-0� or larger 6�

(b) Shafts shall be within 1.5% of plumb. For rock ex-cavation, the allowable tolerance can be increased to2% max.(c) After all the shaft concrete is placed, the portion ofthe shaft reinforcing steel cage embedded in the shaftshall be no more than 1 inch above and no more than 3inches below plan position, and shall be at least 1 inchbelow the top of the shaft.(d) The minimum diameter of the drilled shaft shall bethe diameter shown on the plans for diameters 24inches or less, and not more than 1 inch less than thediameter shown on the plans for diameters greater than24 inches. The maximum shaft diameter shall be the di-ameter shown in the plans, plus 6 inches.(e) The bearing area of bells shall be excavated to theplan bearing area as a minimum. All other dimensionsfor the bells shall be as shown on the approved work-ing drawings.(f) The top elevation of the shaft shall be within 2inches of the plan top of shaft elevation.(g) The bottom of the shaft excavation shall be normalto the axis of the shaft within 3 ⁄4 inch per foot of shaftdiameter.

During drilling or excavation of the shaft, the Contrac-tor shall make frequent checks on the plumbness, align-ment, and dimensions of the shaft. Any deviation exceed-ing the allowable tolerances shall be corrected with aprocedure approved by the Engineer.

Drilled shaft excavations constructed in such a mannerthat the concrete shaft cannot be completed within the re-quired tolerances are unacceptable. Correction methodsshall be submitted by the Contractor for the Engineer’sapproval. Approval will be obtained before continuingwith the drilled shaft construction.

Materials and work necessary to effect correction forout-of-tolerance drilled shaft excavations shall be fur-nished at no additional cost to the Department.

5.4.17 Integrity Testing

When called for in the special provisions, the completedshaft will be subjected to nondestructive testing to determinethe extent of any defects that may be present in the shaft.

Work and materials required for testing which are to befurnished by the Contractor shall be as shown on the plansor special provisions.

In the event testing discloses voids or discontinuities inthe concrete which, as determined by the Engineer, indi-cate that the drilled shaft is not structurally adequate, theshaft shall be rejected. The Contractor shall repair, replaceor supplement the defective work in a manner approvedby the Engineer. The construction of additional drilledshafts shall be discontinued until the Contractor demon-strates the adequacy of the shaft construction method andany subsequent method changes to the satisfaction of theEngineer. Any additional work required as a result of shaftdefects shall be at no additional cost to the Department.

5.5 DRILLED SHAFT LOAD TESTS

When the contract documents include load testing, alltests shall be completed before construction of any pro-duction drilled shafts. The Contractor shall allow twoweeks after the last load test for the analysis of the loadtest data by the Engineer before specified drilled shaft tipelevations will be provided for production shafts.

The locations of load test shafts and reaction shafts, themaximum loads to be applied, the test equipment to befurnished by the Contractor, and the actual performanceof the load testing shall be as shown on the plans or spec-ified in the special provisions.

After testing is completed, the test shafts and any reac-tion shafts, if not also to be used as production shafts, shallbe cutoff at an elevation 3 feet below the finished groundsurface. The portion of the shafts cutoff shall be disposedof by the Contractor in a manner approved by the Engineer.

NOTE: Load tests should generally be performed as aseparate contract in advance of the bridge construction.


5.6.1 Measurement

5.6.1.1 Drilled Shaft

Drilled shafts, complete in place, will be measured bythe linear foot for each size of shaft listed in the scheduleof bid items. Measurement will be along the centerline ofthe shaft based on the tip and shaft cut-off elevations shownon the plans or as ordered by the Engineer.

5.6.1.2 Bell Footings

Bell footings will be measured by the cubic yard,computed by using the dimensions and shape specified on the plans or as revised by the Engineer. The bell shallconsist of the volume outside the plan or authorized di-mensions of the shaft, which will extend to the bottom ofthe bell for the purpose of measurement.



5.6.1.3 Test Shafts

Test shafts of the specified diameter will be measuredfrom the elevation of the ground at the time drilling be-gins, by the linear foot of acceptable test shaft drilled.

5.6.1.4 Test Bells

Test bells will be measured by the cubic yard computedby using the dimensions specified in Article 5.6.1.2.

5.6.1.5 Exploration Holes

Exploration holes will be measured by the linear footmeasured from the bottom of shaft elevation to the bottomof the exploration hole, for each authorized hole drilled.

5.6.1.6 Permanent Casing

Permanent casing will be measured by the linear foot foreach size of casing authorized to be used. Measurement willbe along the casing from top of casing or top of shaft,whichever is lower, to the bottom of the casing at each shaftlocation where permanent casing is authorized and used.

5.6.1.7 Load Tests

Load tests will be measured by the number of load testsperformed for each designated pile load capacity.

5.6.2 Payment

5.6.2.1 Drilled Shaft

Drilled shafts will be paid for at the contract price perlineal foot for drilled shaft of the diameter specified. Suchpayment shall be considered to be full compensation for allcosts involved with shaft excavation, disposal of exca-vated material, and the furnishing and placing of concreteand reinforcing steel, including all labor, materials, equip-ment, temporary casing, and incidentals necessary to com-plete the drilled shafts, except for unexpected obstructions.

5.6.2.2 Bell Footings

Bell footings constructed to the specified or authorizeddimensions will be paid for at the contract unit price percubic yard for bell footings. Such payment shall be fullcompensation for excavation, and concrete beyond the di-ameter of the drilled shaft including all labor, materials,

equipment and incidentals necessary to complete the bellfootings.

5.6.2.3 Test Shafts

Test shafts of the specified diameter will be paid for at thecontract unit price per linear foot for test shafts. Such pay-ment shall be full compensation for excavation and concreteor backfill material including all labor, materials, equip-ment, and incidentals necessary to complete the test shafts.

5.6.2.4 Test Bells

Test bells of the diameter and shape specified or au-thorized and approved will be paid for at the contract unitprice per cubic yard for test bells. Such payment shall befull compensation for excavation and concrete or backfillmaterial including all labor, materials, equipment, and in-cidentals necessary to complete the test bells, except forunexpected obstructions.

5.6.2.5 Exploration Holes

When specified or shown in the plans, explorationholes for soil samples or rock cores will be paid for at thecontract unit price per linear foot for exploration holes.Such payment shall be full compensation for drilling orcoring the holes, extracting and packaging the samples orcores and delivering them to the Department and all otherexpenses necessary to complete the work.

5.6.2.6 Permanent Casing

Permanent casing will be paid for at the contract unitprice per linear foot for permanent casing. Such paymentshall be full compensation for furnishing and placing thecasing above the costs attributable to the work paid forunder associated pay items.

5.6.2.7 Load Tests

Load tests will be paid for at the contract unit pricefor each load test. Such payment shall be full com-pensation for all costs related to the performance of theload tests.

5.6.2.8 Unexpected Obstructions

Removal of unexpected obstructions will be paid forby force account.



Section 6GROUND ANCHORS

6.1 DESCRIPTION

This work shall consist of designing, furnishing, in-stalling, testing, and stressing permanent cement-groutedground anchors in accordance with the plans, these spec-ifications, and the special provisions.


At least 4 weeks before work is to begin, the Contrac-tor shall submit to the Engineer for review and approvalcomplete working drawings and design calculations de-scribing the ground anchor system or systems intended foruse. The submittal shall include the following:

(1) A ground anchor schedule giving:(a) Ground anchor number,(b) Ground anchor design load,(c) Type and size of tendon,(d) Minimum total anchor length,(e) Minimum bond length,(f) Minimum tendon bond length, and(g) Minimum unbonded length.

(2) A drawing of the ground anchor tendon and thecorrosion protection system, including details for thefollowing:

(a) Spacers separating elements of tendon andtheir location,(b) Centralizers and their location,(c) Unbonded length corrosion protection system,(d) Bond length corrosion protection system,(e) Anchorage and trumpet,(f) Anchorage corrosion protection system,(g) Drilled or formed hole size,(h) Level of each stage of grouting, and(i) Any revisions to structure details necessary toaccommodate the ground anchor system intendedfor use.

(3) The grout mix design and procedures for placingthe grout.

The Engineer will approve or reject the Contractor’sworking drawings within 4 weeks of receipt of a complete

submittal. No work on ground anchors shall begin untilworking drawings have been approved in writing by theEngineer. Such approval shall not relieve the Contractorof any responsibility under the contract for the successfulcompletion of the work.

6.3 MATERIALS

6.3.1 Prestressing Steel

Ground anchor tendons shall consist of single or mul-tiple elements of prestressing steel, anchorage devicesand, if required, couplers conforming to the requirementsdescribed in Section 10, “Prestressing.”

The following materials are acceptable for use asground anchor tendons:

AASHTO Designation: M 203 (ASTM DesignationA 416 - Uncoated, 7-wire strand)

ASTM Designation: A886/A886M (Indented, 7-wirestrand)

ASTM Designation: A 882/A 882M (Epoxy coated,7-wire strand)

6.3.2 Grout

Cement shall be Type I, II, or III Portland Cement con-forming to AASHTO M 85. Cement used for groutingshall be fresh and shall not contain any lumps or other in-dications of hydration or “pack set.”

Aggregate shall conform to the requirements for fineaggregate described in Section 8, “Concrete Structures.”

Admixtures may be used in the grout subject to the ap-proval of the Engineer. Expansive admixtures may onlybe added to the grout used for filling sealed encapsula-tions, trumpets, and anchorage covers. Accelerators shallnot be used.

Water for mixing grout shall be potable, clean and freeof injurious quantities of substances known to be harmfulto Portland cement or prestressing steel.

507


6.3.3 Steel Elements

Bearing plates shall be fabricated from steel con-forming to AASHTO M 270 (ASTM A 709) Grade 36minimum, or be a ductile iron casting conforming toASTM A 536.

Trumpets used to provide a transition from the anchor-age to the unbonded length corrosion protection shall befabricated from a steel pipe or tube conforming to the re-quirements of ASTM A 53 for pipe or ASTM A 500 fortubing. Minimum wall thickness shall be 0.20 inches.

Anchorage covers used to enclose exposed anchoragesshall be fabricated from steel, steel pipe, steel tube, orductile cast iron conforming to the requirements ofAASHTO M 270 (ASTM A 709) Grade 36 for steel,ASTM A 53 for pipe, ASTM A 500 for tubing, and ASTMA 536 for ductile cast iron. Minimum thickness shall be0.10 inches.

6.3.4 Corrosion Protection Elements

Corrosion inhibiting grease shall conform to the re-quirements of the Post Tensioning Institute’s “Specifica-tions for Unbonded Single Strand Tendons,” Section 3.2.5.

Sheath for the unbonded length of a tendon shall con-sist of one of the following:

(1) Seamless polyethylene (PE) tube having a mini-mum wall thickness of 60 mils plus or minus 10 mils.The polyethylene shall be cell classification 334413 byASTM D 3350.(2) Seamless polypropylene tube having a minimumwall thickness of 60 mils plus or minus 10 mils. Thepolypropylene shall be cell classificationPP210B55542-11 by ASTM D 4101.(3) Heat shrinkable tube consisting of a radiationcrosslinked polyolefin tube internally coated with anadhesive sealant. The minimum tube wall thickness be-fore shrinking shall be 24 mils. The minimum adhesivesealant thickness shall be 20 mils.(4) Corrugated polyvinyl chloride (PVC) tube havinga minimum wall thickness of 30 mils.

Encapsulation for the tendon bond length shall consistof one of the following:

(1) Corrugated high density polyethylene (HDPE)tube having a minimum wall thickness of 30 mils andconforming to AASHTO M 252 requirements.(2) Deformed steel tube or pipe having a minimumwall thickness of 25 mils.(3) Corrugated polyvinyl chloride (PVC) tube havinga minimum wall thickness of 30 mils.

(4) Fusion-bonded epoxy conforming to the require-ments of AASHTO M 284, except that it shall have afilm thickness of 15 mils.

6.3.5 Miscellaneous Elements

Bondbreaker for a tendon shall consist of smooth plas-tic tube or pipe that is resistant to aging by ultra-violetlight and that is capable of withstanding abrasion, impactand bending during handling and installation.

Spacers for separation of elements of a multi-elementtendon shall permit the free flow of grout. They shall befabricated from plastic, steel, or material which is not detri-mental to the prestressing steel. Wood shall not be used.

Centralizers shall be fabricated from plastic, steel, ormaterial which is not detrimental to either the prestressingsteel or any element of the tendon corrosion protection.Wood shall not be used. The centralizer shall be able tomaintain the position of the tendon so that a minimum of0.5 inches of grout cover is obtained on the tendons, orover the encapsulation.

6.4 FABRICATION

Tendons for ground anchors may be either shop or fieldfabricated from materials conforming to the requirementsof Article 6.3. Tendons shall be fabricated as shown on theapproved working drawings. The tendon shall be sized sothat the maximum test load does not exceed 80% of theminimum guaranteed ultimate strength of the tendon.

6.4.1 Bond Length and Tendon Bond Length

The Contractor shall determine the bond length neces-sary to satisfy the load test requirements. The minimumbond length shall be 10 feet in rock, 15 feet in soil or theminimum length shown on the plans. The minimum ten-don bond length shall be 10 feet.

6.4.1.1 Grout Protected Ground Anchor Tendon

Spacers shall be placed along the tendon bond lengthof multi-element tendons so that the prestressing steel willbond to the grout. They shall be located at 10-foot maxi-mum centers with the upper one located a maximum of 5feet from the top of the tendon bond length and the lowerone located a maximum of 5 feet from the bottom of thetendon bond length.

Centralizers shall be placed along the bond length.They shall be located at 10-foot maximum centers with theupper one located a maximum of 5 feet from the top of thebond length and the lower one located 1 foot from the bot-



tom of the bond length. Centralizers are not required ontendons installed utilizing a hollow-stem auger if it isgrouted through the auger and the drill hole is maintainedfull of a stiff grout (9-inch slump or less) during extractionof the auger. A combination centralizer-spacer may beused.

Centralizers are not required on tendons installed uti-lizing a pressure injection system in coarse-grained soilsusing grouting pressures greater than 150 psi.

6.4.1.2 Encapsulation Protected Ground AnchorTendon

The tendon bond length shall be encapsulated by agrout-filled corrugated plastic or deformed steel tube, orby a fusion-bonded epoxy coating. The tendon can begrouted inside the encapsulation prior to inserting the ten-don in the drill hole or after the tendon has been placed inthe drill hole. Punching holes in the encapsulation and al-lowing the grout to flow from the encapsulation to the drillhole, or vice versa, will not be permitted. The tendon shallbe centralized within the encapsulation and the tube sizedto provide an average of 0.20 inches of grout cover for theprestressing steel. Spacers and centralizers shall be usedto satisfy the same requirements specified in Article6.4.1.1 for grout protected ground anchor tendons. The anchorage device of tendons protected with fusion-bonded epoxy shall be electrically isolated fromthe structure.

6.4.2 Unbonded Length

The unbonded length of the tendon shall be a minimumof 15 feet or as indicated on the plans or approved work-ing drawings.

Corrosion protection shall be provided by a sheathcompletely filled with corrosion inhibiting grease orgrout, or a heat shrinkable tube. If grease is used to fill thesheath, provisions shall be made to prevent it from escap-ing at the ends. The grease shall completely coat the ten-don and fill the interstices between the wires of seven-wire strands. Continuity of corrosion protection shall beprovided at the transition from the bonded length to un-bonded length of the tendon.

If the sheath provided is not a smooth tube, then a sep-arate bondbreaker must be provided to prevent the tendonfrom bonding to the anchor grout surrounding the un-bonded length.

6.4.3 Anchorage and Trumpet

Nonrestressable anchorages may be used unless re-stressable anchorages are designated on the plans or spec-

ified in the special provisions.Bearing plates shall be sized so that the bending

stresses in the plate and average bearing stress on theconcrete, if applicable, do not exceed the allowablestresses described in Division I, Article 9.21.7.2, “Bear-ing Strength.” The size of bearing plates shall not be lessthan that shown on the plans or on the approved workingdrawings.

The trumpet shall be welded to the bearing plate. Thetrumpet shall have an inside diameter at least 0.25 inchesgreater than the diameter of the tendon at the anchorage.The trumpet shall be long enough to accommodate move-ments of the structure during testing and stressing. Forstrand tendons with encapsulation over the unbondedlength, the trumpet shall be long enough to enable the ten-dons to make a transition from the diameter of the tendonin the unbonded length to the diameter of the tendon at theanchorhead without damaging the encapsulation. Trum-pets filled with corrosion-inhibiting grease shall have apermanent Buna-N rubber or approved equal seal pro-vided between the trumpet and the unbonded length cor-rosion protection. Trumpets filled with grout shall have atemporary seal provided between the trumpet and the un-bonded length corrosion protection.

6.4.4 Tendon Storage and Handling

Tendons shall be stored and handled in such a manneras to avoid damage or corrosion. Damage to tendon pre-stressing steel as a result of abrasions, cuts, nicks, weldsand weld splatter will be cause for rejection by the Engi-neer. Grounding of welding leads to the prestressing steelis not permitted. A slight rusting, provided it is not suffi-cient to cause pits visible to the unaided eye, shall not because for rejection. Prior to inserting a tendon into thedrilled hole, its corrosion protection elements shall be ex-amined for damage. Any damage found shall be repairedin a manner approved by the Engineer.

6.5 INSTALLATION

The Contractor shall select the drilling method, thegrouting procedure and grouting pressure to be used forthe installation of the ground anchor as necessary to sat-isfy the load test requirements.

6.5.1 Drilling

The drilling method used may be core drilling, rotarydrilling, percussion drilling, auger drilling or driven cas-ing. The method of drilling used shall prevent loss ofground above the drilled hole that may be detrimental to



the structure or existing structures. Casing for anchorholes, if used, shall be removed, unless permitted by theEngineer to be left in place. The location, inclination, andalignment of the drilled hole shall be as shown on theplans. Inclination and alignment shall be within plus orminus 3° of the planned angle at the bearing plate, andwithin plus or minus 12 inches of the planned location atthe ground surface (point of entry).

6.5.2 Tendon Insertion

The tendon shall be inserted into the drilled hole to the desired depth without difficulty. When the tendoncannot be completely inserted it shall be removed and the drill hole cleaned or redrilled to permit insertion.Partially inserted tendons shall not be driven or forcedinto the hole.

6.5.3 Grouting

A neat cement grout or sand-cement grout conformingto Article 6.3.2 shall be used. Admixtures, if used, shall bemixed in quantities not to exceed the manufacturer’s rec-ommendations.

The grouting equipment shall produce a grout free oflumps and undispersed cement. A positive displacementgrout pump shall be used. The pump shall be equippedwith a pressure gauge to monitor grout pressures. Thepressure gauge shall be capable of measuring pressures ofat least 150 psi or twice the actual grout pressures used,whichever is greater. The grouting equipment shall besized to enable the grout to be pumped in one continuousoperation. The mixer shall be capable of continuously ag-itating the grout.

The grout shall be injected from the lowest point of thedrill hole. The grout may be pumped through grout tubes,casing, hollow-stem augers or drill rods. The grout maybe placed before or after insertion of the tendon. Thequantity of the grout and the grout pressures shall berecorded. The grout pressures and grout takes shall becontrolled to prevent excessive heave of the ground orfracturing of rock formations.

Except where indicated below, the grout above the topof the bond length may be placed at the same time as thebond length grout, but it shall not be placed under pres-sure. The grout at the top of the drill hole shall stop 6inches from the back of the structure or from the bottomof the trumpet, whichever is lowest.

If the ground anchor is installed in a fine-grained soilusing a drilled hole larger than 6 inches in diameter, thenthe grout above the top of the bond length shall be placedafter the ground anchor has been load tested. The entiredrill hole may be grouted at the same time if it can be

demonstrated that the ground anchor system does not de-rive a significant portion of its load resistance from thesoil above the bond length portion of the ground anchor.

If grout protected tendons are used for ground anchorsanchored in rock, then pressure grouting techniques shallbe utilized. Pressure grouting requires that the drill holebe sealed and that the grout be injected until a 50-psi groutpressure can be maintained on the grout within the bondlength for a period of 5 minutes.

Upon completion of grouting, the grout tube may re-main in the drill hole provided it is filled with grout.

After grouting, the tendon shall not be loaded for aminimum of 3 days.

6.5.4 Trumpet and Anchorage

The corrosion protection surrounding the unbondedlength of the tendon shall extend into the trumpet a mini-mum of 6 inches beyond the bottom seal in the trumpet.

The corrosion protection surrounding the unbondedlength of the tendon shall not contact the bearing plate orthe anchorhead during load testing or stressing.

The bearing plate and anchorhead shall be placed per-pendicular to the axis of the tendon.

The trumpet shall be completely filled with corrosioninhibiting grease or grout. The grease may be placed anytime during construction. The grout shall be placed afterthe ground anchor has been load tested. The Contractorshall demonstrate that the procedures selected for place-ment of either grease or grout will produce a completelyfilled trumpet.

Anchorages not encased in concrete shall be coveredwith a corrosion inhibiting grease-filled or grout-filledsteel enclosure.

6.5.5 Testing and Stressing

Each ground anchor shall be load tested by the Con-tractor. No load greater than 10% of the design load maybe applied to the ground anchor prior to load testing. Thetest load shall be simultaneously applied to the entiretendon.

6.5.5.1 Testing Equipment

A dial gauge or vernier scale capable of measuring dis-placements to 0.001 inches shall be used to measureground anchor movement. It shall have adequate travel sototal ground anchor movement can be measured withoutresetting the device.

A hydraulic jack and pump shall be used to apply thetest load. The jack and a calibrated pressure gauge shallbe used to measure the applied load. The pressure gauge



shall be graduated in 100-psi increments or less. When thetheoretical elastic elongation of the total anchor length atthe maximum test load exceeds the ram travel of the jack,the procedure for recycling the jack ram shall be includedin the working drawings. Each increment of test load shallbe applied as rapidly as possible.

A calibrated reference pressure gauge shall be avail-able at the site. The reference gauge shall be calibratedwith the test jack and pressure gauge.

An electrical resistance load cell and readout shall beprovided when performing a creep test.

The stressing equipment shall be placed over theground anchor tendon in such a manner that the jack, bear-ing plates, load cell and stressing anchorage are axiallyaligned with the tendon and the tendon is centered withinthe equipment.

6.5.5.2 Performance Test

Five percent of the ground anchors or a minimum ofthree ground anchors, whichever is greater shall be per-formance tested in accordance with the following proce-dures. The Engineer shall select the ground anchors to beperformance tested. The remaining anchors shall be testedin accordance with the proof test procedures.

The performance test shall be made by incrementallyloading and unloading the ground anchor in accordancewith the following schedule unless a different maximumtest load and schedule are indicated on the plans. The loadshall be raised from one increment to another immediatelyafter recording the ground anchor movement. The groundanchor movement shall be measured and recorded to thenearest 0.001 inches with respect to an independent fixedreference point at the alignment load and at each incre-ment of load. The load shall be monitored with a pressuregauge. The reference pressure gauge shall be placed in se-ries with the pressure gauge during each performance test.If the load determined by the reference pressure gauge andthe load determined by the pressure gauge differ by morethan 10%, the jack, pressure gauge and reference pressuregauge shall be recalibrated. At load increments other thanthe maximum test load, the load shall be held just longenough to obtain the movement reading.

Performance Test Schedule

Load Load

AL AL0.25DL* 0.25DL

AL 0.50DL0.25DL 0.75DL0.50DL* 1.00DL

AL 1.20DL*

0.25DL AL0.50DL 0.25DL0.75DL* 0.50DL

AL 0.75DL0.25DL 1.00DL0.50DL 1.20DL0.75DL 1.33DL*

(Max. test load)1.00DL* Reduce to

lock-off load(Art. 6.5.5.6)

Where: AL � Alignment loadDL � Design load for ground anchor* � Graph required. See last paragraph in this

Article 6.5.5.2.

The maximum test load in a performance test shall beheld for 10 minutes. The jack shall be repumped as nec-essary in order to maintain a constant load. The load-holdperiod shall start as soon as the maximum test load isapplied and the ground anchor movement shall bemeasured and recorded at 1 minute, 2, 3, 4, 5, 6, and 10minutes. If the ground anchor movements between 1minute and 10 minutes exceeds 0.04 inches, themaximum test load shall be held for an additional 50 min-utes. If the load hold is extended, the ground anchormovement shall be recorded at 15 minutes, 20, 25, 30, 45,and 60 minutes.

A graph shall be constructed showing a plot of groundanchor movement versus load for each load incrementmarked with an asterisk (*) in the performance test sched-ule and a plot of the residual ground anchor movement ofthe tendon at each alignment load versus the highest pre-viously applied load. Graph format shall be approved bythe Engineer prior to use.

6.5.5.3 Proof Test

The proof test shall be performed by incremen-tally loading the ground anchor in accordance with the following schedule unless a different maximum test load and schedule are indicated on the plans. The load shall be raised from one increment to another immediately after recording the ground anchor move-ment. The ground anchor movement shall be measuredand recorded to the nearest 0.001 inches with respect to an independent fixed reference point at the align-ment load and at each increment of load. The load shall be monitored with a pressure gauge. At loadincrements other than the maximum test load, the loadshall be held just long enough to obtain the movementreading.



Proof Test Schedule

Load Load

AL 1.00DL0.25DL 1.20DL0.50DL 1.33DL

(Max. test load)0.75DL Reduce to

lock-off load

where: AL� Alignment loadDL� Design load for ground anchor

The maximum test load in a proof test shall be held for 10 minutes. The jack shall be repumped as neces-sary in order to maintain a constant load. The load-hold period shall start as soon as the maximum test load is applied and the ground anchor movement shall bemeasured and recorded at 1 minute, 2, 3, 4, 5, 6, and 10minutes. If the ground anchor movement between 1minute and 10 minutes exceeds 0.04 inches, the maxi-mum test load shall be held for an additional 50 minutes.If the load hold is extended, the ground anchor movementshall be recorded at 15 minutes, 20, 30, 45, and 60minutes. A graph shall be constructed showing a plot ofground anchor movement versus load for each load incre-ment in the proof test. Graph format shall be approved bythe Engineer prior to use.

6.5.5.4 Creep Test

Creep tests shall be performed if required by the plansor special provisions. The Engineer shall select the groundanchors to be creep tested.

The creep test shall be made by incrementally loadingand unloading the ground anchor in accordance with theperformance test schedule used. At the end of each load-ing cycle, the load shall be held constant for the observa-tion period indicated in the creep test schedule below un-less a different maximum test load is indicated on theplans. The times for reading and recording the ground an-chor movement during each observation period shall be 1minute, 2, 3, 4, 5, 6, 10, 15, 20, 25, 30, 45, 60, 75, 90, 100,120, 150, 180, 210, 240, 270, and 300 minutes as appro-priate. Each load-hold period shall start as soon as the testload is applied. In a creep test the pressure gauge and ref-erence pressure gauge will be used to measure the appliedload, and the load cell will be used to monitor smallchanges of load during a constant load-hold period. Thejack shall be repumped as necessary in order to maintaina constant load.

Creep Test Schedule

ObservationPeriod (Minutes)

AL0.25 DL 100.50DL 300.75DL 301.00DL 451.20DL 601.33DL 300

A graph shall be constructed showing a plot of theground anchor movement and the residual movementmeasured in a creep test as described for the performancetest. Also, a graph shall be constructed showing a plot ofthe ground anchor creep movement for each load hold asa function of the logarithm of time. Graph formats shallbe approved by the Engineer prior to use.

6.5.5.5 Ground Anchor Load Test AcceptanceCriteria

A performance-tested or proof-tested ground anchorwith a 10-minute load hold is acceptable if the:

(1) Ground anchor resists the maximum test load withless than 0.04 inches of movement between 1 minuteand 10 minutes; and(2) Total movement at the maximum test load exceeds80% of the theoretical elastic elongation of the un-bonded length.(3) Total movement at the maximum test load may notexceed the theoretical elastic elongation of the un-bonded length plus 50% of the theoretical elastic elon-gation of the bonded length. [Criterion (3) applies onlyfor a performance-tested ground anchor in competentrock.]

A performance-tested or proof-tested ground anchorwith a 60-minute load hold is acceptable if the:

(1) Ground anchor resists the maximum test load witha creep rate that does not exceed 0.08 inches in the lastlog cycle of time; and(2) Total movement at the maximum test load exceeds80% of the theoretical elastic elongation of the un-bonded length.(3) Total movement at the maximum test load may notexceed the theoretical elastic elongation of the un-bonded length plus 50% of the theoretical elastic elon-gation of the bonded length. [Criterion (3) applies onlyfor a performance-tested ground anchor in competentrock.]



A creep-tested ground anchor is acceptable if the:

(1) Ground anchor carries the maximum test load witha creep rate that does not exceed 0.08 inches in the lastlog cycle of time; and(2) Total movement at the maximum test load exceeds80% of the theoretical elastic elongation of the un-bonded length.(3) Total movement at the maximum test load may notexceed the theoretical elastic elongation of the un-bonded length plus 50% of the theoretical elastic elon-gation of the bonded length. [Criterion (3) applies onlyfor a performance-tested ground anchor in competentrock.]

If the total movement of the ground anchor at the max-imum test load does not exceed 80% of the theoreticalelastic elongation of the unbonded length, the ground an-chor shall be replaced at the Contractor’s expense.

A ground anchor which has a creep rate greater than0.08 inches per log cycle of time can be incorporated intothe structure at a design load equal to one-half of its fail-ure load. The failure load is the load resisted by the groundanchor after the load has been allowed to stabilize for 10minutes.

When a ground anchor fails, the Contractor shall mod-ify the design and/or the installation procedures. Thesemodifications may include, but are not limited to, in-stalling a replacement ground anchor, reducing the designload by increasing the number of ground anchors, modi-fying the installation methods, increasing the bond lengthor changing the ground anchor type. Any modificationwhich requires changes to the structure shall be approvedby the Engineer. Any modifications of design or con-

struction procedures shall be without additional cost to theDepartment and without extension of contract time.

Retesting of a ground anchor will not be permitted, ex-cept that regrouted ground anchors may be retested.

6.5.5.6 Lock Off

Upon successful completion of the load testing, theground anchor load shall be reduced to the lock-off loadindicated on the plans and transferred to the anchorage de-vice. The ground anchor may be completely unloadedprior to lock-off. After transferring the load and prior to re-moving the jack, a lift-off load reading shall be made. Thelift-off load shall be within 10% of the specified lock-offload. If the load is not within 10% of the specified lock-offload, the anchorage shall be reset and another lift-off loadreading shall be made. This process shall be repeated untilthe desired lock-off load is obtained.


Ground anchors will be measured and paid for by thenumber of units installed and accepted as shown on theplans or ordered by the Engineer. No change in the num-ber of ground anchors to be paid for will be made becauseof the use by the Contractor of an alternative number ofground anchors.

The contract unit price paid for ground anchors shallinclude full compensation for furnishing all labor, materi-als, tools, equipment, and incidentals, and for doing all thework involved in installing the ground anchors (includingtesting), complete in place, as shown on the plans and asspecified in these specifications and the special provi-sions, and as directed by the Engineer.



Section 7EARTH RETAINING SYSTEMS

7.1 DESCRIPTION

This work shall consist of furnishing and installingearth retaining systems in accordance with the plans, thesespecifications, and the special provisions.

Earth retaining systems include concrete and masonrygravity walls, reinforced concrete retaining walls, sheetpile and soldier pile walls (with and without ground an-chors or other anchorage systems), crib and cellular walls,and mechanically stabilized earth walls.


Working drawings and design calculations shall besubmitted to the Engineer for review and approval at least4 weeks before work is to begin. Such submittals shall berequired (1) for each alternative proprietary or nonpropri-etary earth retaining system proposed as permitted orspecified in the contract, (2) when complete details for thesystem to be constructed are not included in the plans, and(3) when otherwise required by the special provisions orthese specifications. Working drawings and design calcu-lations shall include the following:

(a) Existing ground elevations that have been verifiedby the Contractor for each location involving con-struction wholly or partially in original ground.(b) Layout of wall that will effectively retain the earthbut not less in height or length than that shown for thewall system in the plans.(c) Complete design calculations substantiating thatthe proposed design satisfies the design parameters inthe plans and in the special provisions.(d) Complete details of all elements required for theproper construction of the system, including completematerial specifications.(e) Earthwork requirements including specificationsfor material and compaction of backfill.(f) Details of revisions or additions to drainage sys-tems or other facilities required to accommodate thesystem.(g) Other information required in the plans or specialprovisions or requested by the Engineer.

The Contractor shall not start work on any earth re-taining system for which working drawings are requireduntil such drawings have been approved by the Engineer.Approval of the Contractor’s working drawings shall notrelieve the Contractor of any of his responsibility underthe contract for the successful completion of the work.

7.3 MATERIALS

7.3.1 Concrete

7.3.1.1 Cast-in-Place

Cast-in-place concrete shall conform to the require-ments of Section 8, “Concrete Structures.” The concreteshall be Class A unless otherwise indicated in the contractdocuments.

7.3.1.2 Pneumatically Applied Mortar

Pneumatically applied mortar shall conform to therequirements of Section 24, “Pneumatically AppliedMortar.”

7.3.1.3 Precast Elements

The materials, manufacturing, storage, handling, anderection of precast concrete elements shall conform tothe requirements in Article 8.13, “Precast ConcreteMembers.” Unless otherwise shown on the plans or onthe approved working drawings, Portland cement con-crete used in precast elements shall conform to Class A(AE) with a minimum compressive strength at 28 daysof 4,000 psi.

7.3.1.4 Segmental Concrete Facing Blocks

Masonry concrete blocks used as wall facing elementsshall have a minimum compressive strength of 4,000 psiand a water absorption limit of 5%. In areas of repeatedfreeze-thaw cycles, the facing blocks shall be tested in ac-cordance with ASTM C 1262 to demonstrate durability.The facing blocks shall meet the requirements of ASTM

515


C 1372, except that acceptance regarding durability underthis testing method shall be achieved if the weight loss ofeach of 4 of the 5 specimens at the conclusion of 150 cy-cles does not exceed 1% of its initial weight. Blocks shallalso meet the additional requirements of ASTM C 140.Facing blocks directly exposed to spray from deiced pave-ments shall be sealed after erection with a water resistantcoating or be manufactured with a coating or additive toincrease freeze-thaw resistance.



7.3.3 Structural Steel

Structural steel shall conform to AASHTO M 270(ASTM A 709) Grade 36 unless otherwise specified.

7.3.4 Timber

Timber shall conform to the requirements of Section16, “Timber Structures” and Article 4.2.2, “Timber Piles.”

7.3.5 Drainage Elements

7.3.5.1 Pipe and Perforated Pipe

Pipe and perforated pipe shall conform to subsections708 and 709 of the AASHTO Guide Specifications forHighway Construction.

7.3.5.2 Geotextile

Geotextile shall conform to AASHTO M 288.

7.3.5.3 Permeable Material

Permeable material shall conform to subsection 704 ofthe AASHTO Guide Specifications for Highway Con-struction unless otherwise specified in the contract or theapproved working drawings.

7.3.5.4 Geocomposite Drainage Systems

Geocomposite drainage systems shall conform to therequirements specified in the special provisions or the ap-proved working drawings.

7.3.6 Structure Backfill Material

7.3.6.1 General

All structure backfill material shall consist of materialfree from organic material or other unsuitable material asdetermined by the Engineer. Gradation will be determinedby AASHTO T 27. Grading shall be as follows unless oth-erwise specified.

Sieve Size Percent Passing

3 in. 100No. 4 35–100No. 30 20–100No. 200 0–15

7.3.6.2 Crib and Cellular Walls

Structure backfill material for crib and cellular wallsshall be of such character that it will not sift or flowthrough openings in the wall. For wall heights over 20 feet(6 meters), the following grading shall be required:


3 in. 100No. 4 25–70No. 30 5–20No. 200 0–50

7.3.6.3 Mechanically Stabilized Earth Walls

Structure backfill material for MSE walls shall consistof material free from organic material or other unsuitablematerial as determined by the Engineer. Gradation shallbe determined by AASHTO T 27. Grading shall be as fol-lows unless otherwise specified:


4 in.� 100No. 40 0–60No. 200 0–15*

�For the soil to be considered to be nonaggressive, themaximum soil particle size for geosynthetic reinforce-ment shall be 0.75 inches unless full scale installa-tion damage tests are conducted in accordance withASTM D 5818, or if epoxy coatings are used for steel reinforcements.

*Plasticity index (PI), as determined by AASHTO T 90, shall not exceed 6.

The material shall exhibit an angle of internal frictionof not less than 34°, as determined by the standard Di-



rect Shear Test, AASHTO T 236, on the portion finerthan the No. 10 sieve, utilizing a sample of the materialcompacted to 95% of AASHTO T 99, Methods C or D (with oversized correction as outlined in Note 7) at optimum moisture content. No testing is required forbackfills where 80% of the sizes are greater than 0.75inches.

The materials shall be substantially free of shale orother soft, poor durability particles. The material shallhave a magnesium sulfate soundness loss of less than 30%after four cycles or a sodium sulfate soundness loss of lessthan 15% after five cycles determined in accordance withAASHTO T 104. The soil shall also have an organic con-tent of less than or equal to 1% measured in accordancewith AASHTO T 267 for material finer than the No. 10sieve.

The soil backfill electrochemical requirements for steelsoil reinforcement are as follows:

pH of 5 to 10Resistivity of not less than 3,000 ohm-cmChlorides not greater than 100 ppmSulfates not greater than 200 ppm

If the resistivity is greater than or equal to 5,000 ohm-cm,the chlorides and sulfates requirements may be waived.

The soil backfill electrochemical requirements for per-manent geosynthetic reinforcement are as follows:

pH of 4.5 to 9 for permanent structures 3 to 10 for temporary structures

Recommended test methods for soil chemical propertydetermination include AASHTO T 289 for pH, AASHTOT 288 for resistivity, AASHTO T 291 for chlorides, andAASHTO T 290 for sulfates.

7.4 EARTHWORK

7.4.1 Structure Excavation

Structure excavation for earth retaining systems shallconform to the requirements of Section 1, “Structure Ex-cavation and Backfill,” and as provided below.

7.4.2 Foundation Treatment

Foundation treatment shall conform to the require-ments of Article 1.4.2, “Foundation Preparation and Con-trol of Water” unless otherwise specified or included inthe approved working drawings. If subexcavation of

foundation material is indicated, the Contractor shallperform the excavation to the limits shown. Materialsexcavated shall be replaced with structure backfill mate-rial meeting the requirements for the particular earth re-taining system to be constructed unless a different mate-rial is specified in the special provisions. The materialshall be compacted to a density not less than 95% of themaximum density as determined by AASHTO T 99,Methods C or D (with oversize correction as outlined inNote 7).

7.4.3 Structure Backfill

Placement of structure backfill material shall con-form to the requirements of Articles 1.4.3 and 7.6.Material used shall conform to the requirements of Arti-cle 7.3.6.

7.5 DRAINAGE

Drainage facilities shall be constructed in accor-dance with the details shown on the plans or approvedworking drawings, the special provisions, and these Spec-ifications.

7.5.1 Concrete Gutters

Concrete gutters shall be constructed to the profile in-dicated on the plans or the approved working drawings.Pneumatically applied mortar shall conform to the re-quirements of Section 24, “Pneumatically Applied Mor-tar.” Outlet works shall be provided at sags in the profile,at the low ends of the gutter, and at other indicated loca-tions.

7.5.2 Weep Holes

Weep holes, if specified, shall be constructed at the locations shown on the plans or the approved workingdrawings. A minimum of 2 cubic feet of permeable mate-rial encapsulated with geotextile shall be placed at eachweep hole.

Joints between precast concrete retaining wall facepanels which function as weep holes shall be covered withgeotextile. The geotextile shall be bonded to the face pan-els with adhesive conforming to Federal SpecificationMMM-A-121. The face panels which are to receive thegeotextile shall be dry and thoroughly cleaned of dust andloose materials.



7.5.3 Drainage Blankets

Drainage blankets consisting of permeable mate-rial encapsulated in geotextile, collector pipes, outletpipes and clean out pipes shall be constructed as shown onthe plans or the approved working drawings.

The subgrade to receive the geotextile shall con-form to the compaction and elevation tolerance specifiedand shall be free of loose or extraneous material andsharp objects that may damage the geotextile during installation. The geotextile shall be stretched, aligned,and placed in a wrinkle-free manner. Adjacent borders ofthe geotextile shall be overlapped from 12 to 18 inches.Should the geotextile be damaged, the torn or puncturedsection shall be repaired by placing a piece of geotextilethat is large enough to cover the damaged area and tomeet the overlap requirement.

The permeable material shall be placed in horizontallayers and thoroughly consolidated along with and by thesame methods specified for structure backfill. Pondingand jetting of permeable material or structure backfillmaterial adjacent to permeable material will not be per-mitted. During spreading and compaction of the perme-able material and structure backfill or embankment ma-terial, a minimum of 6 inches of such material shall bemaintained between the geotextile and the Contractor’sequipment.

The perforated collector pipe shall be placed withinthe permeable material to the flow line elevationsshown.

Outlet pipes shall be placed at sags in the flow line, atthe low end of the collector pipe, and at other locationsshown or specified. Rock slope protection, when requiredat the end of outlet pipes, shall conform to the details onthe plans or approved working drawings and the require-ments in Section 22, “Slope Protection.”

Cleanout pipes shall be placed at the high ends of col-lector pipes and at other locations as specified.

7.5.4 Geocomposite Drainage Systems

Geocomposite drainage systems shall be installed atthe locations shown on the plans or the approved workingdrawings. The geocomposite drainage material shall beplaced and secured tightly against the excavated face, lag-ging or back of wall as specified. When concrete is to beplaced against geocomposite drainage materials, thedrainage material shall be protected against physical dam-age and grout leakage.

7.6 CONSTRUCTION

The construction of earth retaining systems shallconform to the lines and grades indicated on the plans or working drawings or as directed by the Engineer.

7.6.1 Concrete and Masonry Gravity Walls,Reinforced Concrete Retaining Walls

Stone masonry construction shall conform to the re-quirements of Section 14, “Stone Masonry.” Concreteconstruction shall conform to the requirements of Section8, “Concrete Structures.” Reinforced concrete block ma-sonry shall conform to the requirements of Section 15,“Concrete Block and Brick Masonry.”

Vertical precast concrete wall elements with cast-in-place concrete footing support shall be adequately sup-ported and braced to prevent settlement or lateral dis-placement until the footing concrete has been placed andhas achieved sufficient strength to support the wall ele-ments.

The exposed face of concrete walls shall receive aClass 1 finish as specified in Section 8, “Concrete Struc-tures,” unless a special architectural treatment is specifiedon the plans, the special provisions, or the approved work-ing drawings.

7.6.2 Sheet Pile and Soldier Pile Walls

This work shall consist of constructing continuouswalls of timber, steel or concrete sheet piles, and the con-structing of soldier pile walls with horizontal facing ele-ments of timber, steel or concrete.

7.6.2.1 Sheet Pile Walls

Steel sheet piles shall be of the type and weight indi-cated on the plans or designated in the special provisions.Steel sheet piles shall conform to the requirements ofAASHTO M 202 (ASTM A 328), AASHTO M 270(ASTM A 709) Grade 50, or to the specifications for “Pil-ing for use in Marine Environments” in ASTM A 690.Painting of steel sheet piles, when required, shall conformto Article 13.2.

Timber sheet piles, unless otherwise specified or per-mitted, shall be treated in accordance with Section 17,“Preservative Treatment of Wood.” The piles shall be ofthe dimensions, species, and grade of timber shown on theplans. The piles may be either cut from solid material ormade by building up with three planks securely fastened



together. The piles shall be drift sharpened at their lowerends so as to wedge adjacent piles tightly together duringdriving.

Concrete sheet piles shall conform to the detailsshown on the plans or the approved working drawings.The manufacture and installation shall conform, in gen-eral, to the requirements for precast concrete bearingpiles in Section 4, “Driven Foundation Piles.” Concretesheet piles detailed to have a tongue and groove joint onthe portion below ground and a double-grooved joint onthe exposed portion shall, after installation, have theupper grooves cleaned of all sand, mud or debris, andgrouted full. Unless otherwise provided in the specialprovisions or approved in writing by the Engineer, groutshall be composed of one part cement and two parts ofsand. The grout shall be deposited through a grout pipeplaced within a watertight plastic sheath extending thefull depth of the grout slot formed by the grooves in twoadjacent pilings and which, when filled, completely fillsthe slot.

Sheet piles shall be driven to the specified penetrationor bearing capacity in accordance with the requirementsof Section 4, “Driven Foundation Piles.”

After driving, the tops of sheet piles shall be neatly cutoff in a workmanlike manner to a straight line at the ele-vation shown on the plans, indicated in the special provi-sions or as directed by the Engineer.

Sheet pile walls shall be braced by wales or other brac-ing system as shown on the plans, indicated in the specialprovisions or directed by the Engineer.

Timber waling strips shall be properly lapped andjoined at all splices and corners. The wales shall prefer-ably be in one length between corners and shall be boltednear the tops of the piles.

Reinforced concrete caps, when indicated on theplans or the approved working drawings, shall be con-structed in accordance with Section 8, “Concrete Struc-tures.”

7.6.2.2 Soldier Pile Walls

Soldier piles shall be either driven piles or piles con-structed in a drilled shaft excavation to the specified pen-etration or bearing capacity indicated on the plans.

Driven piles shall be furnished and installed in accor-dance with the requirements of Section 4, “Driven Foun-dation Piles.” The piles shall be of the type indicated onthe plans.

Piles constructed in a drilled shaft excavation shallconform to the details shown on the plans. Constructionof the shaft excavation and placement of concrete or lean

concrete backfill shall be in accordance with Section 5,“Drilled Piles and Shafts.” The structural component ofthe soldier pile placed in the shaft excavation shall be asspecified on the plans. Reinforced concrete, either cast-in-place or precast, shall conform to the requirements ofSection 8, “Concrete Structures.” Timber members shallconform to the requirements of Section 16, “TimberStructures,” and Section 17, “Preservative Treatment ofWood.” Steel members shall conform to the requirementsof Section 11, “Steel Structures.” Painting of steelmembers, if required, shall conform to Section 13,“Painting.”

Concrete backfill placed around precast concrete, tim-ber or steel pile members in the drilled shaft excavationshall be commercially available Portland cement concretewith a cement content not less than five sacks per cubicyard. Lean concrete backfill shall consist of commercialquality concrete sand, water and not greater than one sackof Portland cement per cubic yard. The limits for place-ment of concrete and lean concrete shall be as indicatedon the plans.

The facing spanning horizontally between soldier pilesshall conform to the materials and details shown on theplans or the approved working drawings. Timber laggingshall conform to the requirements in Section 16, “TimberStructures” and Section 17, “Preservative Treatment ofWood.” Precast concrete lagging or facing panels andcast-in-place concrete facing shall conform to the re-quirements in Section 8, “Concrete Structures.” Concreteanchors, welded connections and bolted connections forsecuring facing elements to the soldier piles shall conformto the details on the plans and the requirements in thespecial provisions.

The exposed surface of concrete wall facing shall re-ceive a Class 1 finish as specified in Section 8, “ConcreteStructures,” unless a special architectural treatment isspecified on the plans, the special provisions, or theapproved working drawings.

7.6.2.3 Anchored Sheet Pile and Soldier PileWalls

7.6.2.3.1 General

The construction of anchored walls shall consist ofconstructing sheet pile and soldier pile walls anchoredwith a tie-rod and concrete anchor system or with groundanchors.

Sheet pile and soldier pile wall construction shall con-form to the requirements of Articles 7.6.2.1 and 7.6.2.2,respectively.



7.6.2.3.2 Wales

Wales consisting of either timber, steel or concreteshall conform to the details on the plans or the approvedworking drawings. The alignment of wales shall be suchthat tie-rods or ground anchors can be installed withoutbending. Timber wales shall conform to the requirementsof Section 16, “Timber Structures,” and Section 17,“Preservative Treatments of Wood.” Steel wales shallconform to the requirements of Section 11, “Steel Struc-tures.” Concrete wales shall conform to the requirementsof Section 8, “Concrete Structures.”

7.6.2.3.3 Concrete Anchor Systems

Concrete anchor systems, consisting of either drilledshafts or reinforced concrete shapes placed within the lim-its of soil or rock excavation, with or without pile support,shall conform to the details on the plans or the approvedworking drawings.

Battered anchor piles shall be driven to the proper bat-ter shown. The tension anchor piles shall be furnishedwith adequate means of anchorage to the concrete anchorblock.

Drilled shaft concrete anchors shall conform to the de-tails on the plans or approved working drawings, and beconstructed in conformance with Section 5, “Drilled Pilesand Shafts.”

7.6.2.3.4 Tie-rods

Tie-rods shall be round steel bars conforming toAASHTO M 270 (ASTM A 709) Grade 36 unless other-wise specified on the plans or in the special provisions.Corrosion protection shall be provided as specified in thespecial provisions. Care shall be taken in the handling andbackfilling operations to prevent damage to the corrosionprotection or bending of the tie-rod itself.

The connection of the tie-rods to the soldier piles,wales, wall face and concrete anchor shall conform to thedetails specified.

7.6.2.3.5 Ground Anchors

Ground anchors shall be constructed in conformancewith the requirements of Section 6, “Ground Anchors.”

The connection of ground anchors to soldier piles,wales, or wall face shall conform to the details on theplans or the approved working drawings.

7.6.2.3.6 Earthwork

Earthwork shall conform to the requirements in Article 7.4.

Unless otherwise specified or permitted, excavation infront of the wall shall not proceed more than 3 feet belowa level of tie-rods or ground anchors until such tie-rodsand anchors or ground anchors are complete and acceptedby the Engineer.

Placement of lagging shall closely follow excavationin front of the wall such that loss of ground is minimized.

7.6.3 Crib Walls and Cellular Walls

This work shall consist of constructing timber, con-crete or steel crib walls, and concrete monolithic cell wallscomplete with backfill material within the cells formed bythe members.

7.6.3.1 Foundation

In addition to the requirements of Article 7.4.2, thefoundation or bed course material shall be finished toexact grade and cross slope so that the vertical or batteredface alignment will be achieved.

When required, timber mud sills, concrete levelingpads or concrete footings shall conform to the details onthe plans. Timber mud sills shall be firmly and evenly bed-ded in the foundation material. Concrete for leveling padsor footings shall be placed against the sides of excavationin the foundation material.

7.6.3.2 Crib Members

Timber header and stretcher members shall conform tothe requirements of Section 16, “Timber Structures,” andunless otherwise specified shall be the same as for caps,posts, and sills. Preservative treatment shall conform tothe requirements of Section 17, “Preservative Treatmentof Wood.” The size of the members shall be as shown onthe plans.

Concrete header and stretcher members shall con-form to the requirements of Section 8, “Concrete Structures,” for precast concrete members. The dimen-sions of the members and minimum concrete strengthshall be as indicated on the plans or the approved work-ing drawings.

Steel crib members consisting of base plates, columns,stretchers and spacers shall be fabricated from sheet steelconforming to AASHTO M 218. Thickness of membersshall be as specified. Crib members shall be so fabricatedthat members of the same nominal size and thicknessshall be fully interchangeable. No drilling, punching, ordrifting to correct defects in manufacture shall be per-mitted. Any members having holes improperly punched



shall be replaced. Bolts, nuts, and miscellaneous hard-ware shall be galvanized in accordance with ASTM A 153.

7.6.3.3 Concrete Monolithic Cell Members

Concrete monolithic cell members consisting of four-sided cells of uniform height and various depths shall becast in conformance with the requirements set forth forprecast members in Section 8, “Concrete Structures.” Theminimum concrete compressive strength shall be 28 MPa.The exposed cell face shall have a Class 1 finish; faces notexposed to view shall have a uniform surface finish freeof open pockets of aggregate or surface distortions in ex-cess of 0.25 inch. The protruding keys and recesses forkeys on the tops and bottoms of the side walls of the cellsshall be accurately located.

7.6.3.4 Member Placement

Timber and concrete crib members shall be placed insuccessive tiers at spacings conforming to the specifieddetails for the particular height of wall being constructed.Drift bolts at the intersection of timber header andstretcher members shall be accurately installed so thatminimum edge distances are maintained. At the intersec-tion of concrete header and stretcher members asphalt feltshims or other approved material shall be used to obtainuniform bearing between the members.

Steel column sections, stretchers and spacers shall con-form to the proper length and weight as specified. Thesemembers shall be accurately aligned to permit completingthe bolted connections without distorting the members.Bolts at the connections shall be torqued to not less than25 foot-pounds.

Concrete monolithic cell members of the proper sizesshall be successively stacked in conformance with the lay-out shown on the plans or the approved working draw-ings. Care shall be exercised in placing the members toprevent damage to the protruding keys. Damaged or ill-fitting keys shall be repaired using a method approved bythe Engineer.

7.6.3.5 Backfilling

The cells formed by the wall members shall be back-filled with structure backfill material conforming to the re-quirements in Article 7.3.6. Backfilling shall progress si-multaneously with the erection of the members formingthe cells. Backfill material shall be so placed and com-pacted as to not disturb or damage the members. Place-ment of backfill shall be in uniform layers not exceeding

300 millimeters (1 foot) in thickness unless otherwise pro-posed by the Contractor and approved by the Engineer.Compaction shall be to a density of at least 95% of themaximum density as determined by AASHTO T 99,Method C. Backfilling behind the wall to the limits of ex-cavation shall conform to the same requirements unlessotherwise indicated or approved.

7.6.4 Mechanically Stabilized Earth Walls

The construction of mechanically stabilized earthwalls shall consist of constructing a facing system towhich steel or polymeric soil reinforcement is connectedand the placing of structure backfill material surroundingthe soil reinforcement.

7.6.4.1 Facing

Facing consisting of either precast concrete panels,cast-in-place concrete panels, pneumatically-applied mor-tar, segmental concrete blocks, or welded wire fabric shallconform to the details and materials indicated on theplans, in the special provisions, or on the approved work-ing drawings.

Precast concrete panels shall be cast in conformancewith the requirements set forth for precast members inSection 8, “Concrete Structures.” The concrete com-pressive strength shall be that specified or 4,000 psi,whichever is greater. The exposed face shall have a Class 1 finish or the architectural treatment indicated onthe plans, in the special provisions, or the approvedworking drawings. The face not exposed to view shallhave a uniform surface finish free of open pockets of aggregate or surface distortions in excess of 0.25 inch.Soil reinforcement connection hardware shall be accu-rately located and secured during concrete placementand shall not contact the panel reinforcing steel. Jointfiller, bearing pads, and joint cover material shall be asspecified.

Cast-in-place concrete facing shall be constructed inconformance with the requirements in Section 8, “Con-crete Structures.” Soil reinforcement extending beyondthe temporary facing shall be embedded in the facing con-crete the minimum dimensions shown on the plans or theapproved working drawings.

Welded wire facing, either temporary or permanent,shall be formed by a 90° bend of the horizontal soil rein-forcement. The vertical portion of the soil reinforcementforming the face shall be connected to the succeedingupper level of soil reinforcement. A separate backing matand hardware cloth shall be placed immediately behind



the vertical portion of soil reinforcement. Its wire size andspacing shall be as specified.

7.6.4.2 Soil Reinforcement

All steel soil reinforcement and any steel connectionhardware shall be galvanized in accordance with ASTMA 123.

Steel strip reinforcement shall be hot rolled to the re-quired shape and dimensions. The steel shall conform toAASHTO M 223 (ASTM A 572) Grade 65 unless other-wise specified.

Welded wire fabric reinforcement shall be shop fabri-cated from cold-drawn wire of the sizes and spacingsshown on the plans or the approved working drawings.The wire shall conform to the requirements of ASTM A82, fabricated fabric shall conform to the requirements ofASTM A 185.

Geosynthetic reinforcement shall be of the type andsize designated on the plans or the approved workingdrawings and shall conform to the specified material andmanufacturing requirements.

Connection hardware shall conform to the details onthe plans and the requirements in the special provisions orthe approved working drawings.

The installation of instrumentation for monitoring cor-rosion shall conform to the requirements specified.


When required, a precast reinforced or a cast-in-placeconcrete leveling pad shall be provided at each panelfoundation level. Prior to placing the leveling pads, thefoundation material shall conform to the requirements ofArticle 7.4.2.

Precast concrete panels, segmental concrete blocks,timber, and welded wire fabric facing shall be placed andsupported as necessary so that their final position is verti-cal or battered as shown on the plans or the approvedworking drawings within a tolerance acceptable to the Engineer.

Joint filler, bearing pads and joint covering materialshall be installed concurrent with face panel placement.

Backfill material conforming to the requirement inArticle 7.3.6 shall be placed and compacted simultane-ously with the placement of facing and soil reinforce-ment. Placement and compaction shall be accomplishedwithout distortion or displacement of the facing or soilreinforcement. Sheepsfoot or grid-type rollers shall not be used for compacting backfill within the limits ofthe soil reinforcement. At each level of soil reinforce-

ment, the backfill material shall be roughly leveled to an elevation approximately 0.1 foot above the level ofconnection at the facing before placing the soil rein-forcement. All soil reinforcement shall be uniformly tensioned to remove any slack in the connection or material.


Unless otherwise designated in the special provisions,earth retaining systems will be measured and paid for bythe square foot. The square meter (square foot) area forpayment will be based on the vertical height and length ofeach section built except in the case when alternative earthretaining systems are permitted in the contract documents.When alternative earth retaining systems are permitted,the square meter (square foot area) for payment will bebased on the vertical height and length of each section of the system type designated as the basis of paymentwhether or not it is actually constructed. The verticalheight of each section will be taken as the difference in elevation on the outer face from the bottom of the low-ermost face element for systems without footings, andfrom the top of footing for systems with footings, to thetop of the wall, excluding any barrier.

The contract price paid per square meter (square foot)for earth retaining systems shall include full compensa-tion for furnishing all labor, materials, tools, equipment,and incidentals, and for doing all the work involved inconstructing the earth retaining systems including—butnot limited to—earthwork, piles, footings, and drainagesystems, complete in place as shown on the plans, asspecified in these specifications and as directed by theEngineer.

Full compensation for revisions to drainage system, orother facilities made necessary by the use of an alternativeearth retaining system shall be considered as included inthe contract price paid per square meter (square foot) forearth retaining system and no adjustment in compensationwill be made therefore.

REFERENCES

Elias, V., 1996, Corrosion/Degradation of Soil Reinforce-ments for Mechanically Stabilized Earth Walls and Re-inforced Soil Slopes, Federal Highway Administration,No. FHWA-DP.82-2.

Elias, V., and Christopher, B.R., 1996, Mechanically Sta-bilized Earth Walls and Reinforced Soil Slopes Design



and Construction Guidelines, Federal Highway Ad-ministration, No. FHWA-DP.82.1.

Federal Highway Administration, 1991, Scour at Bridges,Technical Advisory, T 5150.20, U.S. Department ofTransportation, Federal Highway Administration, 64 p.

Simac, M. R., Bathurst, R. J., Berg, R. R., and Lothspeich,S. E., 1993, Design Manual for Segmental RetainingWalls (Modular Concrete Block Retaining Wall Sys-tems), First Edition, NCMA, Herndon, Virginia.



Section 8CONCRETE STRUCTURES

8.1 GENERAL

8.1.1 Description

This work shall consist of furnishing, placing, finishing, and curing concrete in bridges, culverts, andmiscellaneous structures in accordance with these specifications and conforming to the lines, grades, anddimensions shown on the plans. The work includeselements of structures constructed by cast-in-place andprecast methods using either plain (unreinforced),reinforced, or prestressed concrete or any combinationthereof. The requirements of this section are not applica-ble to precast box culvert structures, which are addressedin Section 27.

8.1.2 Related Work

Other work involved in the construction of concretestructures shall be as specified in the applicable sectionsof this Specification. Especially applicable are Section 3for forms and falsework, Section 9 for reinforcing steel,and Section 10 for prestressing.

8.1.3 Construction Methods

Whenever the specifications permit the Contractor to select the method or equipment to be used for anyoperation, it shall be the Contractor’s responsibility toemploy methods and equipment which will producesatisfactory work under the conditions encountered andwhich will not damage any partially completed portionsof the work.

Falsework and forms shall conform to the require-ments of Section 3, “Temporary Works.”

Generally, all concrete shall be fully supported untilthe required strength and age has been reached. However,the slip form method will be permitted for the construc-tion of pier shafts and railings providing the Contractor’splan assures that: (1) the results will be equal in all respectto those obtained by the use of fixed forms, and (2) ade-

quate arrangements will be provided for curing, finishing,and protecting the concrete.

8.2 CLASSES OF CONCRETE

8.2.1 General

The class of concrete to be used in each part of thestructure shall be as specified or shown on the plans. If notshown or specified, the Engineer will designate the classof concrete to be used.

8.2.2 Normal Weight Concrete

Eight classes of normal weight concrete are providedfor in these Specifications as listed in Table 8.2.

8.2.3 Lightweight Concrete

Lightweight concrete shall conform to the require-ments specified in the special provisions or shown on theplans. When the special provisions require the use of nat-ural sand for a portion or all of the fine aggregate, the nat-ural sand shall conform to AASHTO M 6.

8.3 MATERIALS

8.3.1 Cements

Portland cements shall conform to the requirements ofAASHTO M 85 (ASTM C 150) and Blended Hydrauliccements shall conform to the requirements of AASHTOM 240 (ASTM C 595). For Type 1P Portland-pozzolan ce-ment, the pozzolan constituent shall not exceed 20% ofthe weight of the blend and the loss on ignition of the poz-zolan shall not exceed 5%.

Unless otherwise specified, only Type I, II, or III Port-land Cement, Types IA, IIA, or IIIAAir Entrained PortlandCement, or Types IP or IS Blended Hydraulic cementsshall be used. Types IA, IIA, and IIIA cements may beused only in concrete where air entrainment is required.

525


Low-alkali cements conforming to the requirements ofAASHTO M 85 for low-alkali cement shall be used whenspecified or when ordered by the Engineer as a conditionof use for aggregates of limited alkali-silica reactivity.

Unless otherwise permitted, the product of only one millof any one brand and type of cement shall be used for likeelements of a structure that are exposed to view, exceptwhen cements must be blended for reduction of any exces-sive air-entrainment where air-entraining cement is used.

8.3.2 Water

Water used in mixing and curing of concrete shall besubject to approval and shall be reasonably clean and freeof oil, salt, acid, alkali, sugar, vegetable, or other injurioussubstances. Water will be tested in accordance with, andshall meet the suggested requirements of AASHTO T 26.Water known to be of potable quality may be used with-out test. Where the source of water is relatively shallow,the intake shall be so enclosed as to exclude silt, mud,grass, or other foreign materials.

Mixing water for concrete in which steel is embeddedshall not contain a chloride ion concentration in excess of1,000 ppm or sulphates as SO4 in excess of 1,300 ppm.

8.3.3 Fine Aggregate

Fine aggregate for concrete shall conform to the re-quirements of AASHTO M 6.

8.3.4 Coarse Aggregate

Coarse aggregate for concrete shall conform to the re-quirements of AASHTO M 80.

8.3.5 Lightweight Aggregate

Lightweight aggregate for concrete shall conform tothe requirements of AASHTO M 195 (ASTM C 330).

8.3.6 Air-Entraining and Chemical Admixtures

Air-entraining admixtures shall conform to the re-quirements of AASHTO M 154 (ASTM C 260).

Chemical admixtures shall conform to the require-ments of AASHTO M 194 (ASTM C 494). Unless other-wise specified, only Type A (Water-reducing), Type B(Retarding), Type D (Water-reducing and retarding), TypeF (Water-reducing, high range) or Type G (Water-reduc-ing, high range and retarding) shall be used.


TABLE 8.2


Admixtures containing chloride ion (C1) in excess of1% by weight of the admixture shall not be used in rein-forced concrete. Admixtures in excess of 0.1% shall notbe used in prestressed concrete.

A Certificate of Compliance signed by the manufac-turer of the admixture shall be furnished to the Engineerfor each shipment of admixture used in the work. SaidCertificate shall be based upon laboratory test results froman approved testing facility and shall certify that the ad-mixture meets the above specifications.

If more than one admixture is used, the admixturesshall be compatible with each other and shall be incorpo-rated into the concrete mix in correct sequence so that thedesired effects of all admixtures are obtained.

Air-entraining and chemical admixtures shall be incor-porated into the concrete mix in a water solution. Thewater so included shall be considered to be a portion ofthe allowed mixing water.

8.3.7 Mineral Admixtures

Fly ash pozzolans and calcined natural pozzolans foruse as mineral admixtures in concrete shall conform to therequirements of AASHTO M 295 (ASTM C 618).

The use of fly ash as produced by plants that utilize thelimestone injection process or use compounds of sodium,ammonium or sulphur, such as soda ash, to control stackemissions shall not be used in concrete.

A Certificate of Compliance, based on test results andsigned by the producer of the mineral admixture certify-ing that the material conforms to the above specifications,shall be furnished for each shipment used in the work.

8.3.8 Steel

Materials and installation of reinforcing and pre-stressing steel shall conform to the requirements ofSections 9, “Reinforcing Steel,” and 10, “Prestressing,”respectively.

8.4 PROPORTIONING OF CONCRETE

8.4.1 Mix Design

8.4.1.1 Responsibility and Criteria

The Contractor shall design and be responsible for theperformance of all concrete mixes used in structures. Themix proportions selected shall produce concrete that issufficiently workable and finishable for all uses intendedand shall conform to the requirements in Table 8.2 and allother requirements of this section.

For normal weight concrete the absolute volumemethod, such as described in American Concrete InstitutePublication 211.1, shall be used in selecting mix propor-tions. For structural lightweight concrete, the mix propor-tions shall be selected on the basis of trial mixes with thecement factor rather than the water/cement ratio being de-termined by the specified strength using methods such asthose described in American Concrete Institute Publica-tion 211.2.

The mix design shall be based upon obtaining an aver-age concrete strength sufficiently above the specifiedstrength so that, considering the expected variability ofthe concrete and test procedures, no more than 1 in 10strength tests will be expected to fall below the specifiedstrength. Mix designs shall be modified during the courseof the work when necessary to ensure compliance withstrength and consistency requirements.

8.4.1.2 Trial Batch Tests

For classes A, A(AE) and P concrete, for lightweightconcrete, and for other classes of concrete when specifiedor ordered by the Engineer, satisfactory performance of theproposed mix design shall be verified by laboratory testson trial batches. The results of such tests shall be furnishedto the Engineer by the Contractor or the manufacturer ofprecast elements at the time the proposed mix design issubmitted. For mix design approval, the strengths of a min-imum of five test cylinders taken from a trial batch shallaverage at least 800 psi greater than the specified strength.

If materials and a mix design identical to those pro-posed for use have been used on other work within theprevious year, certified copies of concrete test results fromthis work which indicate full compliance with these spec-ifications may be substituted for such laboratory tests. Ifthe results of more than 10 such strength tests are avail-able from historical records for the past year, averagestrength for these tests shall be at least 1.28 standard de-viations above the specified strength.

8.4.1.3 Approval

All mix designs, and any modifications thereto, shallbe approved by the Engineer prior to use. Mix design dataprovided to the Engineer for each class of concrete re-quired shall include the name, source, type, and brand ofeach of the materials proposed for use and the quantity tobe used per cubic yard of concrete.

8.4.2 Water Content

For calculating the water/cement ratio of the mix, theweight of the water shall be that of the total free water in



the mix which includes the mixing water, the water in anyadmixture solutions and any water in the aggregates in ex-cess of that needed to reach a saturated-surface-dry con-dition.

The amount of water used shall not exceed the limitslisted in Table 8.2 and shall be further reduced as neces-sary to produce concrete of the consistencies listed inTable 8.3 at the time of placement:

When Type F or G high range water reducing admix-tures are used, the above listed slump limits may be ex-ceeded as permitted by the Engineer.

When the consistency of the concrete is found to ex-ceed the nominal slump, the mixture of subsequentbatches shall be adjusted to reduce the slump to a valuewithin the nominal range. Batches of concrete with aslump exceeding the maximum specified shall not be usedin the work.

If concrete of adequate workability cannot be obtainedby the use of the minimum cement content allowed, thecement and water content shall be increased without ex-ceeding the specified water/cement ratio, or an approvedadmixture shall be used.

8.4.3 Cement Content

The minimum cement content shall be as listed inTable 8.2 or otherwise specified. The maximum cement orcement plus mineral admixture content shall not exceed800 pounds per cubic yard of concrete. The actual cementcontent used shall be within these limits and shall be suf-ficient to produce concrete of the required strength andconsistency.

8.4.4 Mineral Admixtures

Mineral admixtures shall be used in the amounts spec-ified. In addition, when either Types I, II, IV, or V

(AASHTO M 85) cements are used and mineral admix-tures are neither specified nor prohibited, the Contractorwill be permitted to replace up to 20% of the required Port-land cement with a mineral admixture. The weight of themineral admixture used shall be equal to or greater than theweight of the Portland cement replaced. In calculating thewater/cement ratio of the mix, the weight of the cementshall be considered to be the sum of the weights of thePortland cement and the mineral admixture.

8.4.5 Air-Entraining and Chemical Admixtures

Air-entraining and chemical admixtures shall be usedas specified. Otherwise, such admixtures may be used, atthe option and expense of the Contractor when permittedby the Engineer, to increase the workability or alter thetime of set of the concrete.

8.5 MANUFACTURE OF CONCRETE

The production of ready-mixed concrete shall conformto the requirements of AASHTO M 157 (ASTM C 94) andthe requirements of this Article 8.5. The production ofconcrete with stationary mixers shall conform to the ap-plicable requirements of AASHTO M 157 (ASTM C 94)and the requirements of this article.

8.5.1 Storage of Aggregates

The handling and storage of concrete aggregates shallbe such as to prevent segregation or contamination withforeign materials. The methods used shall provide for ad-equate drainage so that the moisture content of the aggre-gates is uniform at the time of batching. Different sizes ofaggregate shall be stored in separate stock piles suffi-ciently removed from each other to prevent the material atthe edges of the piles from becoming intermixed.

When specified in Table 8.2 or in the special provi-sions, the coarse aggregate shall be separated into two ormore sizes in order to secure greater uniformity of theconcrete mixture.

8.5.2 Storage of Cement

The Contractor shall provide suitable means for stor-ing and protecting cement against dampness. Cementwhich for any reason has become partially set or whichcontains lumps of caked cement will be rejected. Cementheld in storage for a period of over 3 months if bagged or6 months if bulk, or cement which for any reason theEngineer may suspect of being damaged, shall be subjectto a retest before being used in the work.


TABLE 8.3


Copies of cement records shall be furnished to the En-gineer, showing, in such detail, as he may reasonably re-quire, the quantity used during the day or run at each partof the work.

8.5.3 Measurement of Materials

Materials shall be measured by weighing, except asotherwise specified or where other methods are specifi-cally authorized. The apparatus provided for weighing theaggregates and cement shall be suitably designed and con-structed for this purpose. Each size of aggregate and thecement shall be weighed separately. The accuracy of allweighing devices shall be such that successive quantitiescan be measured to within 1% of the desired amount. Ce-ment in standard packages (sack) need not be weighed,but bulk cement shall be weighed. The mixing water shallbe measured by volume or by weight. The accuracy ofmeasuring the water shall be within a range of error of notover 1%. All measuring devices shall be subject to ap-proval and shall be tested, at the Contractor’s expense,when deemed necessary by the Engineer.

When volumetric measurements are authorized forprojects, the weight proportions shall be converted toequivalent volumetric proportions. In such cases, suitableallowance shall be made for variations in the moisturecondition of the aggregates, including the bulking effectin the fine aggregate.

When sacked cement is used, the quantities of aggre-gates for each batch shall be exactly sufficient for one ormore full sacks of cement and no batch requiring frac-tional sacks of cement will be permitted.

8.5.4 Batching and Mixing Concrete

8.5.4.1 Batching

The size of the batch shall not exceed the capacity ofthe mixer as guaranteed by the manufacturer or as deter-mined by the Standard Requirements of the AssociatedGeneral Contractors of America.

The measured materials shall be batched and chargedinto the mixer by means that will prevent loss of any ma-terials due to effects of wind or other causes.

8.5.4.2 Mixing

The concrete shall be mixed only in the quantity re-quired for immediate use. Mixing shall be sufficient tothoroughly intermingle all mix ingredients into a uniformmixture. Concrete that has developed an initial set shallnot be used. Retempering concrete by adding water willnot be permitted.

For other than transit mixed concrete, the first batch ofconcrete materials placed in the mixer shall contain a suf-ficient excess of cement, sand, and water to coat the insideof the drum without reducing the required mortar contentof the mix.

When mixer performance tests, as described inAASHTO M 157, are not made, the required mixing timefor stationary mixers shall be not less than 90 seconds normore than 5 minutes. The minimum drum revolutions fortransit mixers at the mixing speed recommended by themanufacturer shall not be less than 70 and not less thanthat recommended by the manufacturer.

The timing device on stationary mixers shall beequipped with a bell or other suitable warning device ad-justed to give a clearly audible signal each time the lockis released. In case of failure of the timing device, theContractor will be permitted to operate while it is beingrepaired, provided he furnishes an approved timepieceequipped with minute and second hands. If the timingdevice is not placed in good working order within 24hours, further use of the mixer will be prohibited untilrepairs are made.

For small quantities of concrete needed in emergenciesor for small noncritical elements of the work, concretemay be hand-mixed using methods approved by theEngineer.

Between uses, any mortar coating inside of mixingequipment which sets or dries shall be cleaned from themixer before use is resumed.

8.5.5 Delivery

The organization supplying concrete shall havesufficient plant capacity and transporting apparatus toensure continuous delivery at the rate required. The rate of delivery of concrete during concreting operations shall be such as to provide for the proper handling, placing, and finishing of the concrete. The rate shall besuch that the interval between batches shall not exceed 20 minutes and shall be sufficient to prevent joints withina monolithic pour caused by placing fresh concreteagainst concrete in which initial set has occurred. Themethods of delivering and handling the concrete shall be such as will facilitate placing with the minimum ofrehandling and without damage to the structure or theconcrete.

8.5.6 Sampling and Testing

Compliance with the requirements indicated in thisSection shall be determined in accordance with the fol-lowing standard methods of AASHTO or ASTM:



Sampling Fresh Concrete, AASHTO T 141 (ASTM C 172)

Weight Per Cubic Foot, Yield and Air Content(Gravimetric) of Concrete, AASHTO T 121 (ASTMC 138)

Sieve Analysis of Fine and Coarse Aggregate,AASHTO T 27

Slump of Portland Cement Concrete, AASHTO T119 (ASTM C 143)

Air Content of Freshly Mixed Concrete by thePressure Method, AASHTO T 152 (ASTM C 231)

Specific Gravity and Absorption of Fine Aggregate,AASHTO T 84 (ASTM C 128)

Specific Gravity and Absorption of Coarse Aggre-gate, AASHTO T 85 (ASTM C 127)

Unit Weight of Structural Lightweight Concrete,ASTM C 567

Making and Curing Concrete Test Specimens in theLaboratory, AASHTO T 126 (ASTM C 192)

Making and Curing Concrete Test Specimens in theField, AASHTO T 23 (ASTM C 31)

Compressive Strength of Cylindrical Concrete Spec-imens, AASHTO T 22 (ASTM C 39)

8.5.7 Evaluation of Concrete Strength

8.5.7.1 Tests

A strength test shall consist of the average strength of two compressive strength test cylinders fabricated from material taken from a single randomly selected batch of concrete, except that, if any cylinder should show evidence of improper sampling, molding, or test-ing, said cylinder shall be discarded and the strength test shall consist of the strength of the remaining cylinder.

8.5.7.2 For Controlling Construction Operations

For determining adequacy of cure and protection, andfor determining when loads or stresses can be applied toconcrete structures, test cylinders shall be cured at thestructure site under conditions that are not more favorablethan the most unfavorable conditions for the portions ofthe structure which they represent as described in Article9.4 of AASHTO T 23. Sufficient test cylinders shall bemade and tested at the appropriate ages to determine whenoperations such as release of falsework, application ofprestressing forces or placing the structure in service canoccur.

8.5.7.3 For Acceptance of Concrete

For determining compliance of concrete with a speci-fied 28-day strength, test cylinders shall be cured undercontrolled conditions as described in Article 9.3 ofAASHTO T 23 and tested at the age of 28 days. Samplesfor acceptance tests for each class of concrete shall betaken not less than once a day nor less than once for each150 cubic yards of concrete or once for each majorplacement.

Any concrete represented by a test which indicates astrength which is less than the specified 28-day compres-sive strength by more than 500 psi will be rejected andshall be removed and replaced with acceptable concrete.Such rejection shall prevail unless either:

(1) The Contractor, at own expense, obtains and sub-mits evidence of a type acceptable to the Engineer thatthe strength and quality of the rejected concrete is ac-ceptable. If such evidence consists of cores taken fromthe work, the cores shall be obtained and tested in ac-cordance with the standard methods of AASHTO T 24 (ASTM C 42) or,(2) The Engineer determines that said concrete is lo-cated where it will not create an intolerable detrimen-tal effect on the structure and the Contractor agrees toa reduced payment to compensate the Department forloss of durability and other lost benefits.

8.5.7.4 For Control of Mix Design

Whenever the average of three consecutive tests,which were made to determine acceptability of concrete,falls to less than 150 psi above the specified strength orany single test falls more than 200 psi below the specifiedstrength, the Contractor shall, at own expense, make cor-rective changes in the materials, mix proportions or in theconcrete manufacturing procedures before placing addi-tional concrete of that class. Such changes must be ap-proved by the Engineer prior to use.

8.5.7.5 Steam and Radiant Heat-Cured Concrete

When a precast concrete member is steam or radiantheat-cured, the compressive strength test cylinders madefor any of the above purposes shall be cured under condi-tions similar to the member. Such concrete will be con-sidered to be acceptable whenever a test indicates that theconcrete has reached the specified 28-day compressivestrength provided such strength is reached not more than28 days after the member is cast.



8.6 PROTECTION OF CONCRETE FROMENVIRONMENTAL CONDITIONS

8.6.1 General

Precautions shall be taken as needed to protect con-crete from damage due to weather or other environmentalconditions during placing and curing operations. Concretethat has been frozen or otherwise damaged by weatherconditions shall be either repaired to an acceptable condi-tion or removed and replaced.

The temperature of the concrete mixture immediatelybefore placement shall be between 50°F and 90°F, exceptas otherwise provided herein.

8.6.2 Rain Protection

Under conditions of rain, the placing of concrete shallnot commence or shall be stopped unless adequate pro-tection is provided to prevent damage to the surface mor-tar or damaging flow or wash of the concrete surface.

8.6.3 Hot Weather Protection

When the ambient temperature is above 90°F, theforms, reinforcing steel, steel beam flanges, and other sur-faces which will come in contact with the mix shall becooled to below 90°F by means of a water spray or otherapproved methods.

The temperature of the concrete at time of placementshall be maintained within the specified temperature rangeby any combination of the following:

• Shading the materials storage areas or the produc-tion equipment.

• Cooling the aggregates by sprinkling with waterwhich conforms to the requirements of Article 8.3.2.

• Cooling the aggregates or water by refrigeration orreplacing a portion or all of the mix water with icethat is flaked or crushed to the extent that the ice willcompletely melt during mixing of the concrete.

• Liquid nitrogen injection.

8.6.4 Cold Weather Protection

8.6.4.1 Protection During Cure

When there is a probability of air temperatures below35°F during the cure period, the Contractor shall submitfor approval by the Engineer prior to concrete placement,a cold weather concreting and curing plan detailing themethods and equipment which will be used to assure thatthe required concrete temperatures are maintained. The

concrete shall be maintained at a temperature of not lessthan 45°F for the first six days after-placement except thatwhen pozzolan cement or fly ash cement is used, this pe-riod shall be as follows:

The above requirement for an extended period of con-trolled temperature may be waived if a compressivestrength of 65% of the specified 28-day design strength isachieved in 6 days.

If external heating is employed, the heat shall be ap-plied and withdrawn gradually and uniformly so that nopart of the concrete surface is heated to more than 90°F orcaused to change temperature by more than 20°F in 8hours.

When requested by the Engineer, the Contractor shallprovide and install two maximum-minimum type ther-mometers at each structure site. Such thermometers shallbe installed as directed by the Engineer so as to monitorthe temperature of the concrete and the surrounding airduring the cure period.

8.6.4.2 Mixing and Placing

When the air temperature is below 35°F, the tempera-ture of the concrete at the time of placement in sectionsless than 12 inches thick shall be not less than 60°F. Re-gardless of air temperature, aggregates shall be free of ice,frost and frozen lumps when batched and concrete shallnot be placed against any material whose temperature is32°F or less.

8.6.4.3 Heating of Mix

When necessary in order to produce concrete of thespecified temperature, either the mix water or the aggre-gates, or both, shall be heated prior to batching. Heatingshall be done in a manner which is not detrimental to themix and does not prevent the entrainment of the requiredamount of air. The methods used shall heat the materialsuniformly. Aggregates shall not be heated directly by gasor oil flame or on sheet metal over fire. Neither aggregatesnor water shall be heated to over 150°F. If either areheated to over 100°F, they shall be mixed together prior tothe addition of the cement so that the cement does notcome into contact with materials which are in excess of100°F.



8.6.5 Special Requirements for Bridge Decks

During periods of low humidity, wind or high temper-atures and prior to the application of curing materials,concrete being placed and finished for bridge decks shallbe protected from damage due to rapid evaporation. Suchprotection shall be adequate to prevent premature crustingof the surface or an increase in drying cracking. Such pro-tection shall be provided by raising the humidity of thesurrounding air with fog sprayers operated upwind of thedeck, the use of wind-breaks or sun-shades, additionallyreducing of the temperature of the concrete, schedulingplacement during the cooler times of days or nights, orany combination thereof.

For bridge decks that are located over or adjacent tosalt water or when specified, the maximum temperature ofthe concrete at time of placement shall be 80°F.

8.6.6 Concrete Exposed to Salt Water

Unless otherwise specifically provided, concrete forstructures exposed to salt or brackish water shall be ClassS for concrete placed under water and Class A for otherwork. Such concrete shall be mixed for a period of not lessthan 2 minutes and the water content of the mixture shallbe carefully controlled and regulated so as to produce con-crete of maximum impermeability. The concrete shall bethoroughly consolidated as necessary to produce maxi-mum density and a complete lack of rock pockets. Unlessotherwise indicated on the plans, the clear distance fromthe face of the concrete to the reinforcing steel shall be notless than 4 inches. No construction joints shall be formedbetween levels of extreme low water and extreme highwater or the upper limit of wave action as determined bythe Engineer. Between these levels the forms shall not beremoved, or other means provided, to prevent salt waterfrom coming in direct contact with the concrete for a pe-riod of not less than 30 days after placement. Except forthe repair of any rock pockets and the plugging of form tieholes, the original surface as the concrete comes from theforms shall be left undisturbed. Special handling shall beprovided for precast members to avoid even slight defor-mation cracks.

8.6.7 Concrete Exposed to Sulfate Soils or Water

When the special provisions identify the area as con-taining sulfate soils or water, the concrete that will be incontact with such soil or water shall be mixed, placed, andprotected from contact with soil or water as required forconcrete exposed to salt water except that the protectionperiod shall be not less than 72 hours.

8.7 HANDLING AND PLACING CONCRETE

8.7.1 General

Concrete shall be handled, placed, and consolidated bymethods that will not cause segregation of the mix andwill result in a dense homogeneous concrete which is freeof voids and rock pockets. The methods used shall notcause displacement of reinforcing steel or other materialsto be embedded in the concrete. Concrete shall be placedand consolidated prior to initial set and in no case morethan 11 ⁄2 hours after the cement was added to the mix.Retempering the concrete by adding water to the mix shallnot be done.

Concrete shall not be placed until the forms, all mate-rials to be embedded and, for spread footings, the ade-quacy of the foundation material have been inspected andapproved by the Engineer. All mortar from previousplacements, debris, and foreign material shall be removedfrom the forms and steel prior to commencing placement.The forms and subgrade shall be thoroughly moistenedwith water immediately before concrete is placed againstthem. Temporary form spreader devices may be left inplace until concrete placement precludes their need, afterwhich they shall be removed.

Placement of concrete for each section of the structureshall be done continuously without interruption betweenplanned construction or expansion joints. The deliveryrate, placing sequence and methods shall be such thatfresh concrete is always placed and consolidated againstpreviously placed concrete before initial set has occurredin the previously placed concrete.

During and after placement of concrete, care shall betaken not to injure the concrete or break the bond with re-inforcing steel. Workmen shall not walk in fresh concrete.Platforms for workmen and equipment shall not be sup-ported directly on any reinforcing steel. Once the concreteis set, forces shall not be applied to the forms or to rein-forcing bars, which project from the concrete, until theconcrete is of sufficient strength to resist damage.

8.7.2 Sequence of Placement

Whenever a concrete placement plan or schedule isspecified or approved, the sequence of placement shallconform to the plan. Unless otherwise specifically per-mitted by such a placement plan, the requirements of thefollowing paragraphs shall apply.

8.7.2.1 Vertical Members

Concrete for columns, substructure and culvert walls,and other similar vertical members shall be placed and al-



lowed to set and settle for a period of time before concretefor integral horizontal members, such as caps, slabs, orfootings is placed. Such period shall be adequate to allowcompletion of settlement due to loss of bleed water andshall be not less than 12 hours for vertical members over15 feet in height and not less than 30 minutes for membersover 5 feet but not over 15 feet in height. When frictioncollars or falsework brackets are mounted on such verti-cal members and unless otherwise approved, the verticalmember shall have been in place at least 7 days and shallhave attained its specified strength before loads from hor-izontal members are applied.

8.7.2.2 Superstructures

Unless otherwise permitted, no concrete shall beplaced in the superstructure until substructure forms havebeen stripped sufficiently to determine the character of thesupporting substructure concrete.

Concrete for T-beam or deck girder spans whose depthis less than 4 feet may be placed in one continuous oper-ation or may be placed in two separate operations; first, tothe top of the girder stems, and second, to completion. ForT-beam or deck girder spans whose depth is 4 feet or moreand, unless the falsework is nonyielding, such concreteshall be placed in two operations and at least 5 days shallelapse after placement of stems before the top deck slab is placed.

Concrete for box girders may be placed in two or threeseparate operations consisting of bottom slab, girderstems and top slab. In either case the bottom slab shall beplaced first and, unless otherwise permitted by the Engi-neer, the top slab shall not be placed until the girder stemshave been in place for at least 5 days.

8.7.2.3 Arches

The concrete in arch rings shall be placed in such amanner as to load the centering uniformly and symmetri-cally. Arch rings shall be cast in transverse sections ofsuch size that each section can be cast in a continuous op-eration. The arrangement of the sections and the sequenceof placing shall be as approved and shall be such as toavoid the creation of initial stress in the reinforcement.The sections shall be bonded together by suitable keys ordowels. Arch barrels for culverts and, unless prohibited bythe special provisions, other arches may be cast in a sin-gle continuous operation.

8.7.2.4 Box Culverts

In general, the base slab or footings of box culvertsshall be placed and allowed to set before the remainder of

the culvert is constructed. For culverts whose wall heightis 5 feet or less, the sidewalls and top slab may be placedin one continuous operation. For higher culvert walls therequirements for vertical members shall apply.

8.7.2.5 Precast Elements

The sequence of placement for concrete in precast ele-ments shall be such that sound well-consolidated concretewhich is free of settlement or shrinkage cracks is pro-duced throughout the member.

8.7.3 Placing Methods

8.7.3.1 General

Concrete shall be placed as nearly as possible in itsfinal position and the use of vibrators for extensive shift-ing of the mass of fresh concrete will not be permitted.

Concrete shall be placed in horizontal layers of a thick-ness not exceeding the capacity of the vibrator to consol-idate the concrete and merge it with the previous lift. Inno case shall the depth of a lift exceed 2 feet. The rate ofconcrete placement shall not exceed that assumed for thedesign of the forms as corrected for the actual temperatureof the concrete being placed.

When placing operations would involve dropping theconcrete more than 5 feet, the concrete shall be droppedthrough a tube fitted with a hopper head, or through otherapproved devices, as necessary to prevent segregation ofthe mix and spattering of mortar on steel and forms abovethe elevation of the lift being placed. This requirementshall not apply to cast-in-place piling when concreteplacement is completed before initial set occurs in the first-placed concrete.

8.7.3.2 Equipment

All equipment used to place concrete shall be of ade-quate capacity and designed and operated so as to preventsegregation of the mix or loss of mortar. Such equipmentshall not cause vibrations that might damage the freshlyplaced concrete. No equipment shall have aluminum partswhich come in contact with the concrete. Between uses,the mortar coating inside of placing equipment which setsor dries out shall be cleaned from the equipment beforeuse is resumed.

Chutes shall be lined with smooth watertight materialand, when steep slopes are involved, shall be equippedwith baffles or reverses.

Concrete pumps shall be operated such that a continu-ous stream of concrete without air pockets is produced.When pumping is completed, the concrete remaining in



the pipeline, if it is to be used, shall be ejected in such amanner that there will be no contamination of the concreteor separation of the ingredients.

Conveyor belt systems shall not exceed a total lengthof 550 lineal feet, measured from end to end of the totalassembly. The belt assembly shall be so arranged that eachsection discharges into a vertical hopper arrangement tothe next section. To keep segregation to a minimum,scrapers shall be situated over the hopper of each sectionso as to remove mortar adhering to the belt and to depositit into the hopper. The discharge end of the conveyor beltsystem shall be equipped with a hopper, and a chute orsuitable deflectors to cause the concrete to drop verticallyto the deposit area.

8.7.4 Consolidation

All concrete, except concrete placed under water andconcrete otherwise exempt, shall be consolidated by me-chanical vibration immediately after placement.

The vibration shall be internal except that externalform vibrators may be used for thin sections when theforms have been designed for external vibration.

Vibrators shall be of approved type and design and ofa size appropriate for the work. They shall be capable oftransmitting vibration to the concrete at frequencies of notless than 4,500 impulses per minute.

The Contractor shall provide a sufficient number of vi-brators to properly compact each batch immediately afterit is placed in the forms. The Contractor shall also have atleast one spare vibrator immediately available in case ofbreakdown.

Vibrators shall be manipulated so as to thoroughly workthe concrete around the reinforcement and imbedded fix-tures and into the corners and angles of the forms. Vibra-tion shall be applied at the point of deposit and in the areaof freshly deposited concrete. The vibrators shall be in-serted and withdrawn out of the concrete slowly. The vi-bration shall be of sufficient duration and intensity to thor-oughly consolidate the concrete, but shall not be continuedso as to cause segregation. Vibration shall not be continuedat any one point to the extent that localized areas of groutare formed. Application of vibrators shall be at points uni-formly spaced and not farther apart than 1.5 times the ra-dius over which the vibration is visibly effective.

Vibration shall not be applied directly to, or throughthe reinforcement to sections or layers of concrete whichhave hardened to the degree that the concrete ceases to beplastic under vibration. Vibrators shall not be used totransport concrete in the forms.

When immersion-type vibrators are used to consoli-date concrete around epoxy-coated reinforcement, the vibrators shall be equipped with rubber or other non-metallic coating.

Vibration shall be supplemented by such spading as isnecessary to ensure smooth surfaces and dense concretealong form surfaces and in corners and locations impossi-ble to reach with the vibrators.

When approved by the Engineer, concrete for smallnoncritical elements may be consolidated by the use ofsuitable rods and spades.

8.7.5 Underwater Placement

8.7.5.1 General

Only concrete used in cofferdams to seal out watermay be placed under water unless otherwise specified orspecifically approved by the Engineer. If other than ClassS concrete is to be placed under water, the minimum ce-ment content of the mix shall be increased by 10% to com-pensate for loss due to wash.

To prevent segregation, concrete placed under watershall be carefully placed in a compact mass, in its final po-sition, by means of a tremie, concrete pump, or other ap-proved method, and shall not be disturbed after being de-posited. Still water shall be maintained at the point ofdeposit and the forms under water shall be watertight.Cofferdams shall be vented during the placement and cureof concrete to equalize the hydrostatic pressure and thusprevent flow of water through the concrete.

Concrete placed under water shall be placed con-tinuously from start to finish. The surface of the concreteshall be kept as nearly horizontal as practicable. Toensure thorough bonding, each succeeding layer of seal shall be placed before the preceding layer has taken initial set. For large pours, more than one tremie orpump shall be used to ensure compliance with thisrequirement.

8.7.5.2 Equipment

A tremie shall consist of a watertight tube having a di-ameter of not less than 10 inches and fitted with a hopperat the top. The tremies shall be supported so as to permitfree movement of the discharge end over the entire topsurface of the work and so as to permit rapid loweringwhen necessary to retard or stop the flow of concrete. Thedischarge end shall be sealed closed at the start of work soas to prevent water from entering the tube before the tubeis filled with concrete. After placement has started thetremie tube shall be kept full of concrete to the bottom ofthe hopper. If water enters the tube after placement isstarted, the tremie shall be withdrawn, the discharge endresealed, and the placement restarted. When a batch isdumped into the hopper, the flow of concrete shall be in-duced by slightly raising the discharge end, always keep-



ing it in the deposited concrete. The flow shall be contin-uous until the work is completed. When cofferdam strutsprevent lateral movement of tremies, one tremie shall beused in each bay.

Concrete pumps used to place concrete under watershall include a device at the end of the discharge tube toseal out water while the tube is first being filled with con-crete. Once the flow of concrete is started, the end of thedischarge tube shall be kept full of concrete and below thesurface of the deposited concrete until placement iscompleted.

8.7.5.3 Cleanup

Dewatering may proceed after test specimens curedunder similar conditions indicate that the concrete has suf-ficient strength to resist the expected loads. All laitance orother unsatisfactory materials shall be removed from theexposed surface by scraping, chipping, or other meanswhich will not injure the surface of the concrete beforeplacing foundation concrete.

8.8 CONSTRUCTION JOINTS

8.8.1 General

Construction joints shall be made only where locatedon plans, or shown in the pouring schedule, unless other-wise approved. All planned reinforcing steel shall extenduninterrupted through joints. In the case of emergency,construction joints shall be placed as directed by the En-gineer and, if directed, additional reinforcing steel dowelsshall be placed across the joint. Such additional steel shallbe furnished and placed at the Contractor’s expense.

8.8.2 Bonding

Unless otherwise shown on the plans, horizontal jointsmay be made without keys and vertical joints shall be con-structed with shear keys. Surfaces of fresh concrete at hor-izontal construction joints shall be rough floated suffi-ciently to thoroughly consolidate the surface andintentionally left in a roughened condition. Shear keysshall consist of formed depressions in the surface cover-ing approximately one-third of the contact surface. Theforms for keys shall be beveled so that removal will notdamage the concrete.

All construction joints shall be cleaned of surfacelaitance, curing compound and other foreign materialsbefore fresh concrete is placed against the surface of the joint. Abrasive blast or other approved methods shallbe used to clean horizontal construction joints to the

extent that clean aggregate is exposed. All constructionjoints shall be flushed with water and allowed to dry to asurface dry condition immediately prior to placingconcrete.

8.8.3 Bonding and Doweling to Existing Structures

When new concrete is shown on the plans to bebonded to existing concrete structures, the existing con-crete shall be cleaned and flushed as specified above.When the plans show reinforcing dowels grouted intoholes drilled in the existing concrete at such constructionjoints, the holes shall be drilled by methods that will notshatter or damage the concrete adjacent to the holes. Thediameters of the drilled holes shall be 1 ⁄4 inch larger thanthe nominal diameter of the dowels unless shown other-wise on the plans. The grout shall be a neat cement pasteof Portland cement and water. The water content shall benot more than 4 gallons per 94 pounds of cement. Retem-pering of grout will not be permitted. Immediately priorto placing the dowels, the holes shall be cleaned of dustand other deleterious materials, shall be thoroughly satu-rated with water, have all free water removed and theholes shall be dried to a saturated surface dry condition.Sufficient grout shall be placed in the holes so that novoids remain after the dowels are inserted. Grout shall becured for a period of at least 3 days or until dowels areencased in concrete.

When specified or approved by the Engineer, epoxymay be used in lieu of Portland cement grout for the bond-ing of dowels in existing concrete. When used, epoxyshall be mixed and placed in accordance with the manu-facturer’s recommendations.

8.8.4 Forms at Construction Joints

When forms at construction joints overlap previouslyplaced concrete, they shall be retightened before deposit-ing new concrete. The face edges of all joints that are ex-posed to view shall be neatly formed with straight bulk-heads or grade strips, or otherwise carefully finishedtrue-to-line and elevation.

8.9 EXPANSION AND CONTRACTION JOINTS

8.9.1 General

Expansion and contraction joints shall be constructedat the locations and in accordance with the details shownon the plans. Such joints include open joints, filled joints,joints sealed with sealants or waterstops, joints reinforcedwith steel armor plates or shapes and joints with combi-nations of these features.




When preformed elastomeric compression joint sealsor bridge deck joint seal assemblies are required, theyshall conform to the requirements of Section 19, “BridgeDeck Joint Seals.”

8.9.2 Materials

8.9.2.1 Premolded Expansion Joint Fillers

Premolded fillers shall conform to one of the followingspecifications:

Specification for Preformed Expansion Joint Fillersfor Concrete Paving and Structural Construction,AASHTO M 213 (ASTM 1751).

Specification for Preformed Sponge Rubber andCork Expansion Joint Fillers for Concrete Pavingand Structural Construction, AASHTO M 153(ASTM D 1752). Type II (cork) shall not be usedwhen resiliency is required.

Specification for Preformed Expansion Joint Fillerfor Concrete, AASHTO M 33 (ASTM D 994).

8.9.2.2 Polystyrene Board Fillers

Board fillers shall be expanded polystyrene with a min-imum flexural strength of 35 pounds per square inch, asdetermined by ASTM C 203, and a compressive yieldstrength of between 16 and 40 pounds per square inch at5% compression. When shown on the plans, or requiredto prevent damage during concrete placement, the surfaceof polystyrene board shall be faced with 1 ⁄8-inch thickhardboard conforming to Federal Specification LLL-B-810.

8.9.2.3 Contraction Joint Material

Material placed in contraction joints shall consist of as-phalt saturated felt paper or other approved bond-break-ing material.

8.9.2.4 Pourable Joint Sealants

Pourable sealants for placement along the top edges ofcontraction or filled expansion joints shall conform to thefollowing:

Hot-poured sealants shall conform to ASTM D 3406,except that when the sealant will be in contact withasphaltic material, it shall conform to ASTM D3405.

Cold-poured sealant shall be silicone type conform-ing to Federal Specification TT-S-1543, Class A.The sealant shall be a one-part, low-modulus sili-

cone rubber type with an ultimate elongation of1,200%.

Polyethylene foam strip, for use when shown on theplans, shall be of commercial quality with a contin-uous impervious glazed top surface, suitable for re-taining the liquid sealant at the proper elevation inthe joint while hardening.

8.9.2.5 Metal Armor

Expansion joint armor assemblies shall be fabricatedfrom steel in conformance with the requirements of Sec-tion 23, “Miscellaneous Metal.” Assemblies shall be ac-curately fabricated and straightened at the shop after fab-rication and galvanizing, as necessary to conform to theconcrete section.

8.9.2.6 Waterstops

Waterstops shall be of the type, size, and shape shownon the plans. They shall be dense, homogeneous, andwithout holes or other defects.

8.9.2.6.1 Rubber Waterstops

Rubber waterstops shall be formed from syntheticrubber made exclusively from neoprene, reinforcing car-bon black, zinc oxide, polymerization agents, and soft-eners. This compound shall contain not less than 70% byvolume of neoprene. The tensile strength shall not be lessthan 2,750 pounds per square inch with an elongation atbreaking of 600%. The Shore Durometer indication(hardness) shall be between 50 and 60. After seven daysin air at temperature of 158° (�2)°F or after 4 days inoxygen at 158° (�2)°F and 300 pounds per square inchpressure, the tensile strength shall not be less than 65%of the original.

Rubber waterstops shall be formed with an integralcross section in suitable molds, so as to produce a uniformsection with a permissible variation in dimension of 1 ⁄32

inch plus or minus. No splices will be permitted in straightstrips. Strips and special connection pieces shall be wellcured in a manner such that any cross section shall bedense, homogeneous, and free from all porosity. Junctionsin the special connection pieces shall be full molded. Dur-ing the vulcanizing period, the joints shall be securelyheld by suitable clamps. The material at the splices shallbe dense and homogeneous throughout the cross section.

8.9.2.6.2 Polyvinylchloride Waterstops

Polyvinylchloride waterstops shall be manufactured bythe extrusion process from an elastomeric plastic com-


pound, the basic resin of which shall be polyvinylchloride(PVC). The compound shall contain any additional resins,plasticizers, stabilizers, or other materials needed to en-sure that, when the material is compounded, it will meetthe performance requirements given in this Specification.No reclaimed PVC or other material shall be used.

The material shall comply with the following physicalrequirements when tested under the indicated ASTM testmethod:

8.9.2.6.3 Copper Waterstops

Sheet copper shall conform to the Specifications forCopper Sheet, Strip, Plate, and Rolled Bar, AASHTO M138 (ASTM B 152) and shall meet the Embrittlement Testof Section 10 of AASHTO M 138.

8.9.2.6.4 Testing of Waterstop Material

The manufacturer shall be responsible for the testing,either in his own or in a recognized commercial labora-tory, of all waterstop materials, and shall submit three cer-tified copies of test results to the Engineer.

8.9.3 Installation

8.9.3.1 Open Joints

Open joints shall be constructed by the insertion andsubsequent removal of a wood strip, metal plate, or otherapproved material. The insertion and removal of the tem-plate shall be accomplished without chipping or breakingthe corners of the concrete. When not protected by metalarmor, open joints in decks and sidewalks shall be finishedwith an edging tool. Upon completion of concrete finish-ing work, all mortar and other debris shall be removedfrom open joints.

8.9.3.2 Filled Joints

When filled joints are shown on the plans, premolded-type fillers shall be used unless polystyrene board is specif-ically called for. Filler for each joint shall consist of as fewpieces of material as possible. Abutting edges of filler ma-terial shall be accurately held in alignment with each otherand tightly fit or taped as necessary to prevent the intrusionof grout. Joint filler material shall be anchored to one sideof the joint by waterproof adhesive or other methods so as

to prevent it from working out of the joint but not interferewith the compression of the material.

8.9.3.3 Sealed Joints

Prior to installation of pourable joint sealants, all for-eign material shall be removed from the joint, the fillermaterial shall be cut back to the depth shown or approvedand the surface of the concrete which will be in contactwith the sealant cleaned by light sand blasting. When re-quired, a polyethylene foam strip shall be placed in thejoint to retain the sealant and isolate it from the filler ma-terial. The sealant materials shall then be mixed and in-stalled in accordance with the manufacturer’s directions.Any material that fails to bond to the sides of the jointwithin 24 hours after placement shall be removed and re-placed.

8.9.3.4 Waterstops

Adequate waterstops of metal, rubber, or plastic shallbe placed as shown on the plans. Where movement at thejoint is provided for, the waterstops shall be of a type per-mitting such movement without injury. They shall bespliced, welded, or soldered, to form continuous water-tight joints.

Precautions shall be taken so that the waterstops shallbe neither displaced nor damaged by construction opera-tions or other means. All surfaces of the waterstops shallbe kept free from oil, grease, dried mortar, or any otherforeign matter while the waterstop is being embedded inconcrete. Means shall be used to insure that all portions ofthe waterstop designed for embedment shall be tightly en-closed by dense concrete.

8.9.3.5 Expansion Joint Armor Assemblies

Armor assemblies shall be installed so that their top sur-face matches the plane of the adjacent finished concretesurface throughout the length of the assembly. Positivemethods shall be employed in placing the assemblies tokeep them in correct position during the placing of the con-crete. The opening at expansion joints shall be that desig-nated on the plans at normal temperature or as directed bythe Engineer for other temperatures, and care shall betaken to avoid impairment of the clearance in any manner.

8.10 FINISHING PLASTIC CONCRETE

8.10.1 General

Unless otherwise specified, after concrete has been con-solidated and prior to the application of cure, all surfaces



of concrete which are not placed against forms shall bestruck-off to the planned elevation or slope and the surfacefinished by floating with a wooden float sufficiently to sealthe surface. While the concrete is still in a workable state,all construction and expansion joints shall be carefullytooled with an edger. Joint filler shall be left exposed.

8.10.2 Roadway Surface Finish

All bridge decks, approach slabs, and other concretesurfaces for use by traffic shall be finished to a smoothskid-resistant surface in accordance with this article. Dur-ing finishing operations the contractor shall provide suit-able and adequate work bridges for proper performance ofthe work, including the application of fog sprays and cur-ing compound, and for inspecting the work.

8.10.2.1 Striking Off and Floating

After the concrete is placed and consolidated ac-cording to Article 8.7, bridge decks or top slabs ofstructures serving as finished pavements shall be finishedusing approved power-driven finishing machines. Hand-finishing methods may be used if approved by theEngineer for short bridges 50 feet or less in length or forirregular areas where the use of a machine would beimpractical.

All surfaces shall be struck-off by equipment supportedby and traveling on rails or headers. The rails, headers, andstrike-off equipment shall be of sufficient strength and beadjusted so that the concrete surface after strike-off willconform to the planned profile and cross section.

The rails or headers shall be set on nonyielding sup-ports and shall be completely in place and firmly securedfor the scheduled length for concrete placement beforeplacing of concrete will be permitted. Rails for finishingmachines shall extend beyond both ends of the scheduledlength for concrete placement a sufficient distance thatwill permit the float of the finishing machine to fully clearthe concrete to be placed. Rails or headers shall be ad-justable for elevation and shall be set to allow for antici-pated settlement, camber, and deflection of falsework, asnecessary to obtain a finished surface true to the requiredgrade and cross section. Rails or headers shall be of a typeand shall be so installed that no springing or deflectionwill occur under the weight of the finishing equipment andshall be so located that finishing equipment may operatewithout interruption over the entire surface being finished.Rails or headers shall be adjusted as necessary to correctfor unanticipated settlement or deflection that may occurduring finishing operations. If rail supports are locatedwithin the area where concrete is being placed, as soon asthey are no longer needed they shall be removed to at least2 inches below the finished surface and the void filledwith fresh concrete.

Before the delivery of concrete is begun, the finishingmachine or, if used, the hand-operated strike-off tool shallbe operated over the entire area to be finished to check forexcessive rail deflections, for proper deck thickness, andcover on reinforcing steel, and to verify operation of allequipment. Any necessary corrections shall be made be-fore concrete placement is begun.

The finishing machine shall go over each area of thesurface as many times as it is required to obtain the re-quired profile and cross section. A slight excess of con-crete shall be kept in front of the cutting edge of the screedat all times. This excess of concrete shall be carried all theway to the edge of the pour or form and shall not beworked into the slab, but shall be wasted.

After strike-off, the surface shall be finished with afloat, roller, or other approved device as necessary to re-move any local irregularities and to leave sufficient mor-tar at the surface of the concrete for later texturing.

During finishing operations, excess water, laitance, orforeign materials brought to the surface during the courseof the finishing operations shall not be reworked into theslab, but shall be removed immediately upon appearanceby means of a squeegee or straightedge drawn from thecenter of the slab towards either edge.

The addition of water to the surface of the concrete toassist in finishing operations will not be permitted.

8.10.2.2 Straightedging

After finishing as described above, the entire surfaceshall be checked by the Contractor with a 10-foot metalstraightedge operated parallel to the center line of thebridge and shall show no deviation in excess of 1 ⁄8 inchfrom the testing edge of the straightedge. For deck sur-faces that are to be overlaid with 1 inch or more of anothermaterial, such deviation shall not exceed 3 ⁄8 inch in 10feet. Deviations in excess of these requirements shall becorrected before the concrete sets. The checking operationshall progress by overlapping the straightedge at leastone-half the length of the preceding pass.

8.10.2.3 Texturing

The surface shall be given a skid-resistant texture byeither burlap or carpet dragging, brooming, tining, or by acombination of these methods. The method employedshall be as specified or as approved by the Engineer. Sur-faces that are to be covered with a waterproofing mem-brane deck seal shall not be coarse textured. They shall befinished to a smooth surface, free of mortar ridges andother projections.

This operation shall be done after floating and at suchtime and in such manner that the desired texture will beachieved while minimizing displacement of the larger ag-gregate particles.



8.10.2.3.1 Dragged

If the surface texture is to be a drag finish, the surfaceshall be finished by dragging a seamless strip of dampburlap over the full width of the surface. The burlap dragshall consist of sufficient layers of burlap and have suffi-cient length in contact with the concrete to slightly groovethe surface and shall be moved forward with a minimumbow of the lead edge. The drag shall be kept damp, clean,and free of particles of hardened concrete. As an alter-native to burlap, the Engineer may approve or direct thatcarpet or artificial turf of approved type and size be sub-stituted.

8.10.2.3.2 Broomed

If the surface texture is to be a broom finish, the surfaceshall be broomed when the concrete has hardened suffi-ciently. The broom shall be of an approved type. Thestrokes shall be square across the slab, from edge to edge,with adjacent strokes slightly overlapped, and shall bemade by drawing the broom without tearing the concrete,but so as to produce regular corrugations not over 1 ⁄8 of aninch in depth. The surface as thus finished shall be freefrom porous spots, irregularities, depressions, and smallpockets or rough spots such as may be caused by the acci-dental disturbing of particles of coarse aggregate embed-ded near the surface during the final brooming operation.

8.10.2.3.3 Tined

If the surface is to be tined, the tining shall be in atransverse direction using a wire broom, comb or finnedfloat having a single row of tines or fins. The tininggrooves shall be between 1 ⁄16 inch and 3 ⁄16 inch wide andbetween 1 ⁄8 inch and 3 ⁄16 inch deep, spaced 1 ⁄2 to 3 ⁄4 inchon centers. Tining shall be discontinued 12 inches fromthe curb line on bridge decks. The area adjacent to thecurbs shall be given a light broom finish longitudinally. Asan alternative, tining may be achieved using an approvedmachine designed specifically for tining or grooving con-crete pavements.

8.10.2.4 Surface Testing and Correction

After the concrete has hardened, an inspection of fin-ished deck roadway surfaces, which will not be overlaidwith a wearing surface, will be made by the Engineer. Anyvariations in the surface which exceed 1 ⁄8 inch from a 10-foot straightedge will be marked. The Contractor shallcorrect such irregularities by the use of concrete planingor grooving equipment which produces a textured surfaceequal in roughness to the surrounding unground concretewithout shattering or otherwise damaging the remainingconcrete.

8.10.3 Pedestrian Walkway Surface Finish

After the concrete for sidewalks and decks of pedes-trian structures has been deposited in place, it shall beconsolidated and the surface shall be struck off by meansof a strike board and floated with wooden or cork float. Ifdirected, the surface shall then be lightly broomed in atransverse direction. An edging tool shall be used onedges and expansion joints. The surface shall not varymore than 1 ⁄8 inch under a 5-foot straightedge. The surfaceshall have a granular or matte texture that will not be slip-pery when wet.

Sidewalk surfaces shall be laid out in blocks with anapproved grooving tool as shown on the plans or as di-rected.

8.10.4 Troweled and Brushed Finish

Surfaces which are shown on the plans or specified tobe troweled shall first be finished as specified underArticle 8.10.1 then, after the concrete is partially set, thesurface shall be finished to a smooth surface by trowelingwith a steel trowel until a slick surface free of bleed wateris produced. The surface shall then be brushed with a finebrush using parallel strokes.

8.10.5 Surface Under Bearings

When metallic masonry plates are to be placed directlyon the concrete or on filler material less than 1 ⁄8-inch thick,the surface shall first be finished with a float finish. Afterthe concrete has set, the area which will be in contact withthe masonry plate shall be ground as necessary to providefull and even bearing. When such plates are to be set onfiller material between 1 ⁄8 and 1 ⁄2-inch thick, the concretesurface shall be steel-trowel finished without brushing andthe flatness of the finished surface shall not vary from astraightedge laid on the surface in any direction within thelimits of the masonry plate by more than 1 ⁄16 inch. Sur-faces which fail to conform to the required flatness shallbe ground until acceptable.

Surfaces under elastomeric bearings and under metallicmasonry plates which are supported on mortar or fillerpads 1 ⁄2 inch or greater in thickness shall be finished bywood floating to a flat and even surface free of ridges.

8.11 CURING CONCRETE

8.11.1 General

All newly placed concrete shall be cured so as to pre-vent loss of water by use of one or more of the methodsspecified herein. Curing shall commence immediately



after the free water has left the surface and finishing op-erations are completed. If the surface of the concrete be-gins to dry before the selected cure method can be applied,the surface of the concrete shall be kept moist by a fogspray applied so as not to damage the surface.

Curing by other than steam or radiant heat methodsshall continue uninterrupted for 7 days except that whenpozzolans in excess of 10%, by weight, of the Portland ce-ment are used in the mix. When such pozzolans are used,the curing period shall be 10 days. For other than top slabsof structures serving as finished pavements, the above cur-ing periods may be reduced and curing terminated whentest cylinders cured under the same conditions as thestructure indicate that concrete strengths of at least 70%of that specified have been reached.

When deemed necessary by the Engineer during peri-ods of hot weather, water shall be applied to concrete sur-faces being cured by the liquid membrane method or bythe forms-in-place method, until the Engineer determinesthat a cooling effect is no longer required. Such applica-tion of water will be paid for as extra work.

8.11.2 Materials

8.11.2.1 Water

Water shall conform to the requirements of Article8.3.2.

8.11.2.2 Liquid Membranes

Liquid membrane-forming compounds for curing con-crete shall conform to the requirements of AASHTO M148 (ASTM C 309).

8.11.2.3 Waterproof Sheet Materials

Waterproof paper, polyethylene film, and white burlappolyethylene sheet shall conform to the requirements ofAASHTO M 171 (ASTM C 171).

8.11.3 Methods

8.11.3.1 Forms-In-Place Method

Formed surfaces of concrete may be cured by retainingthe forms in place without loosening for the required time.

8.11.3.2 Water Method

Concrete surface shall be kept continuously wet byponding, spraying or covering with materials that are keptcontinuously and thoroughly wet. Such materials may

consist of cotton mats, multiple layers of burlap or otherapproved materials which do not discolor or otherwisedamage the concrete.

8.11.3.3 Liquid Membrane Curing CompoundMethod

The liquid membrane method shall not be used on sur-faces where a rubbed finish is required or on surfaces ofconstruction joints unless it is removed by sand blastingprior to placement of concrete against the joint. Type 2,white pigmented, liquid membranes may be used only onthe surfaces of bridge decks, on surfaces that will not beexposed to view in the completed work or on surfaceswhere their use has been approved by the Engineer.

When membrane curing is used, the exposed concreteshall be thoroughly sealed immediately after the freewater has left the surface. Formed surfaces shall be sealedimmediately after the forms are removed and necessaryfinishing has been done. The solution shall be applied bypower-operated atomizing spray equipment in one or twoseparate applications. Hand-operated sprayers may beused for coating small areas. Membrane solutions con-taining pigments shall be thoroughly mixed prior to useand agitated during application. If the solution is appliedin two increments, the second application shall follow thefirst application within 30 minutes. Satisfactory equip-ment shall be provided, together with means to properlycontrol and assure the direct application of the curing so-lution on the concrete surface so as to result in a uniformcoverage at the rate of 1 gallon for each 150 square feet of area.

If rain falls on the newly coated concrete before thefilm has dried sufficiently to resist damage, or if the filmis damaged in any other manner during the curing period,a new coat of the solution shall be applied to the affectedportions equal in curing value to that above specified.

8.11.3.4 Waterproof Cover Method

This method shall consist of covering the surface witha waterproof sheet material so as to prevent moisture lossfrom the concrete. This method may be used only whenthe covering can be secured adequately to prevent mois-ture loss.

The concrete shall be wet at the time the cover isinstalled. The sheets shall be of the widest practicablewidth and adjacent sheets shall overlap a minimum of 6 inches and shall be tightly sealed with pressuresensitive tape, mastic, glue, or other approved methods toform a complete waterproof cover of the entire concretesurface. The paper shall be secured so that wind will notdisplace it. Should any portion of the sheets be broken or



damaged before expiration of the curing period, thebroken or damaged portions shall be immediatelyrepaired. Sections that have lost their waterproofqualities shall not be used.

8.11.3.5 Steam or Radiant Heat Curing Method

This method may be used only for precast concretemembers manufactured in established plants.

Steam curing or radiant heat curing shall be done undera suitable enclosure to contain the live steam or the heat.Steam shall be low pressure and saturated. Temperaturerecording devices shall be employed as necessary to ver-ify that temperatures are uniform throughout the enclo-sure and within the limits specified.

The initial application of the steam or of the heat shallbe from 2 to 4 hours after the final placement of concreteto allow the initial set of the concrete to take place. If re-tarders are used, the waiting period before application ofthe steam or of the radiant heat shall be increased to be-tween 4 and 6 hours after placement. The time of initialset may be determined by the “Standard Method of Testfor Time of Setting of Concrete Mixtures by PenetrationResistance,” AASHTO T 197 (ASTM C 403), and thetime limits described above may then be waived.

During the waiting period, the temperature within thecuring chamber shall not be less than 50°F and live steamor radiant heat may be used to maintain the curing cham-ber at the proper minimum temperature. During this pe-riod the concrete shall be kept wet.

Application of live steam shall not be directed on theconcrete or on the forms so as to cause localized high tem-peratures. During the initial application of live steam or ofradiant heat, the ambient temperature within the curingenclosure shall increase at an average rate not exceeding40°F per hour until the curing temperature is reached. Themaximum curing temperature within the enclosure shallnot exceed 160°F. The maximum temperature shall beheld until the concrete has reached the desired strength. Indiscontinuing the steam application, the ambient air tem-perature shall not decrease at a rate to exceed 40°F perhour until a temperature 20°F above the temperature ofthe air to which the concrete will be exposed has beenreached.

Radiant heat may be applied by means of pipes circu-lating steam, hot oil or hot water, or by electric heating el-ements. Radiant heat curing shall be done under a suitableenclosure to contain the heat, and moisture loss shall beminimized by covering all exposed concrete surfaces witha plastic sheeting or by applying an approved liquid mem-brane-curing compound to all exposed concrete surfaces.Top surfaces of concrete members to be used in compos-ite construction shall be clear of residue of the membrane

curing compound so as not to reduce bond below designlimits. Surfaces of concrete members to which other ma-terials will be bonded in the finished structure shall beclear of residue of the membrane curing compound so asnot to reduce bond below design limits.

Unless the ambient temperature is maintained above60°F, for prestressed members the transfer of the stressingforce to the concrete shall be accomplished immediatelyafter the steam curing or the heat curing has been discon-tinued.

8.11.4 Bridge Decks

The top surfaces of bridge decks shall be cured by acombination of the liquid membrane curing compoundmethod and the water method. The liquid membrane shallbe Type 2, white pigmented, and shall be applied from fin-ishing bridges progressively and immediately after finish-ing operations are complete on each portion of the deck.The water cure shall be applied not later than 4 hours aftercompletion of deck finishing or, for portions of the deckson which finishing is completed after normal workinghours, the water cure shall be applied not later than the fol-lowing morning.

8.12 FINISHING FORMED CONCRETESURFACES

8.12.1 General

Surface finishes for formed concrete surfaces shall beclassified as follows:

Class 1. Ordinary Surface FinishClass 2. Rubbed FinishClass 3. Tooled FinishClass 4. Sandblast FinishClass 5. Wire Brush, or Scrubbed Finish

All concrete shall be given a Class 1, Ordinary SurfaceFinish, and in addition if further finishing is required, suchother type of finish as is specified.

If not otherwise specified, exposed surfaces except thesoffits of superstructures and the interior faces and bot-toms of concrete girders shall also be given a Class 2,Rubbed Finish.

Class 3, 4, or 5 type surface finishes shall be appliedonly where shown on the plans or specified.

8.12.2 Class 1—Ordinary Surface Finish

Immediately following the removal of forms, fins, andirregular projections shall be removed from all surfaces



which are to be exposed or waterproofed. Bulges and off-sets in such surfaces shall be removed with carborundumstones or discs.

Localized poorly bonded rock pockets or honey-combed concrete shall be removed and replaced withsound concrete or packed mortar as specified in Article8.14. If rock pockets, in the opinion of the Engineer, areof such an extent or character as to affect the strength ofthe structure materially or to endanger the life of the steelreinforcement, he or she may declare the concrete defec-tive and require the removal and replacement of the por-tions of the structure affected.

On all surfaces, the cavities produced by form ties andall other holes, broken corners or edges, and other defectsshall be thoroughly cleaned, and after having been thor-oughly saturated with water shall be carefully pointed andtrued with a mortar conforming to Article 8.14. For ex-posed surfaces, white cement shall be added to the mortarin an amount sufficient to result in a patch which, whendry, matches the surrounding concrete. Mortar used inpointing shall be not more than 1 hour old. The concreteshall then be rubbed if required or the cure continued asspecified under Article 8.10. Construction and expansionjoints in the completed work shall be left carefully tooledand free of mortar and concrete. The joint filler shall beleft exposed for its full length with clean and true edges.

The resulting surfaces shall be true and uniform. Re-paired surfaces, the appearance of which is not satisfac-tory, shall be “rubbed” as specified under Class 2, RubbedFinish.

8.12.3 Class 2—Rubbed Finish

After removal of forms, the rubbing of concrete shall bestarted as soon as its condition will permit. Immediatelybefore starting this work, the concrete shall be thoroughlysaturated with water. Sufficient time shall have elapsed be-fore the wetting down to allow the mortar used in thepointing of rod holes and defects to thoroughly set. Sur-faces to be finished shall be rubbed with a medium coarsecarborundum stone, using a small amount of mortar on itsface. The mortar shall be composed of cement and finesand mixed in proportions used in the concrete being fin-ished. Rubbing shall be continued until form marks, pro-jections, and irregularities have been removed, voids havebeen filled, and a uniform surface has been obtained. Thepaste produced by this rubbing shall be left in place.

After other work which could effect the surface hasbeen completed, the final finish shall be obtained by rub-bing with a fine carborundum stone and water. This rub-bing shall be continued until the entire surface is of asmooth texture and uniform color.

After the final rubbing is completed and the surface hasdried, it shall be rubbed with burlap to remove loose pow-der and shall be left free from all unsound patches, paste,powder, and objectionable marks.

When metal forms, fiber forms, lined forms or ply-wood forms in good condition are used, the requirementfor a Class 2, Rubbed Finish may be waived by the Engi-neer when the uniformity of color and texture obtainedwith Class 1 finishing are essentially equal to that whichcould be attained with the application of a Class 2,Rubbed Finish. In such cases, grinding with powered discgrinders or light sandblasting with fine sand or othermeans approved by the Engineer may be utilized in con-junction with Class 1 finishing.

8.12.4 Class 3—Tooled Finish

Finish of this character for panels and other like work may be secured by the use of a bushhammer, pick,crandall, or other approved tool. Air tools, preferably,shall be employed. No tooling shall be done until the con-crete has set for at least 14 days and as much longer asmay be necessary to prevent the aggregate particles frombeing “picked” out of the surface. The finished surfaceshall show a grouping of broken aggregate particles in amatrix of mortar, each aggregate particle being in slightrelief.

8.12.5 Class 4—Sandblasted Finish

The thoroughly cured concrete surface shall be sand-blasted with hard, sharp sand to produce an even fine-grained surface in which the mortar has been cut away,leaving the aggregate exposed.

8.12.6 Class 5—Wire Brushed or Scrubbed Finish

As soon as the forms are removed and while the con-crete is yet comparatively green, the surface shall be thor-oughly and evenly scrubbed with stiff wire or fiberbrushes, using a solution of muriatic acid in the propor-tion of one part acid to four parts water until the cementfilm or surface is completely removed and the aggregateparticles are exposed, leaving an even-pebbled texturepresenting an appearance grading from that of fine gran-ite to coarse conglomerate, depending upon the size andgrading of aggregate used. When the scrubbing has pro-gressed sufficiently to produce the texture desired, the en-tire surface shall be thoroughly washed with water towhich a small amount of ammonia has been added, to re-move all traces of acid.



8.13 PRECAST CONCRETE MEMBERS

8.13.1 General

Precast concrete members shall be constructed andplaced in the work in conformance with the details shownon the plans, specified or shown on the approved workingdrawings.

If approved by the Engineer, the use of precasting meth-ods may be used for elements of the work which are oth-erwise indicated to be constructed by the cast-in-placemethod. When such precasting is proposed, the Contractorshall submit working drawings showing construction jointdetails and any other information required by the Engineer.


Whenever specified or requested by the Engineer, theContractor shall provide working drawings for precastmembers. Such drawings shall include all details not pro-vided in the plans for the construction and the erection ofthe members and shall be approved before any membersare cast. Such approval shall not relieve the Contractor ofany responsibility under the contract for the successfulcompletion of the work.

8.13.3 Materials and Manufacture

The materials and manufacturing processes used forprecast concrete members shall conform to the require-ments of the other articles in this section except as thoserequirements are modified or supplemented by the provi-sions that follow.

When precast members are manufactured in estab-lished casting yards, the manufacturer shall be responsi-ble for the continuous monitoring of the quality of all ma-terials and concrete strengths. Tests shall be performed inaccordance with appropriate AASHTO or ASTM meth-ods. The Engineer shall be allowed to observe all sam-pling and testing and the results of all tests shall be madeavailable to the Engineer.

Established, Precast Concrete Manufacturing Plantsshall be certified under the Precast/Prestressed ConcreteInstitute (PCI) Certification Program or alternative equiv-alent program for the category of work being manu-factured.

Plant Quality Control personnel shall be certified inthe PCI Quality Control Personnel Certification Program,Level II. Plant Quality Control Managers shall be certi-fied PCI Level III. These requirements may be met by al-ternative experience and certification considered to beequivalent.

Precast members shall be cast on unyielding beds orpallets. Special care shall be used in casting the bearingsurfaces so that they will join properly with other ele-ments of the structure.

For prestressed precast units, several units may be castin one continuous line and stressed at one time. Sufficientspace shall be left between ends of units to permit accessfor cutting of tendons after the concrete has attained therequired strength.

The side forms may be removed as soon as their re-moval will not cause distortion of the concrete surface,providing that curing is not interrupted. Members shallnot be lifted from casting beds until their strength is suf-ficient to prevent damage.

When cast-in-place concrete will later be cast againstthe top surfaces of precast beams or girders, these surfacesshall be finished to a coarse texture by brooming with astiff coarse broom. Prior to shipment, such surfaces shallbe cleaned of laitance or other foreign material by sand-blasting or other approved methods.

When precast members are designed to be abutted to-gether in the finished work, each member shall be match-cast with its adjacent segments to ensure proper fit duringerection. As the segments are match-cast they must beprecisely aligned to achieve the final structure geometry.During the alignment, adjustments to compensate for de-flections shall be made.

8.13.4 Curing

Unless otherwise permitted, precast members shall becured by either the water method or the steam or radiantheat method.

8.13.5 Storage and Handling

Extreme care shall be exercised in handling and mov-ing precast prestressed concrete members. Precast girdersshall be transported in an upright position and the pointsof support and directions of the reactions with respect tothe member shall be approximately the same during trans-portation and storage as when the member is in its finalposition.

Prestressed concrete members shall not be shipped untiltests on concrete cylinders, manufactured of the same con-crete and cured under the same conditions as the girders,indicate that the concrete of the particular member has at-tained a compressive strength equal to the specified designcompressive strength of the concrete in the member.

Care shall be taken during storage, hoisting, and han-dling of the precast units to prevent cracking or damage.Units damaged by improper storage or handling shall bereplaced at the Contractor’s expense.



8.13.6 Erection

The Contractor shall be responsible for the safety ofprecast members during all stages of construction. Liftingdevices shall be used in a manner that does not cause dam-aging bending or torsional forces. After a member hasbeen erected and until it is secured to the structure, tem-porary braces shall be provided as necessary to resist windor other loads.

Precast deck form panels shall be erected and placed sothat the fit of mating surfaces shall be such that excessivegrout leakage will not occur. If such fit is not provided,joints shall be dry-packed or sealed with an acceptablecaulking compound prior to placing the cast-in-place con-crete. End panels for skewed structures may be sawed tofit the skew.

8.13.7 Epoxy Bonding Agents for PrecastSegmental Box Girders

8.13.7.1 Materials

Epoxy bonding agents for match cast joints shall bethermosetting 100% solid compositions that do not con-tain solvent or any nonreactive organic ingredient exceptfor pigments required for coloring. Epoxy bonding agentsshall be of two components, a resin and a hardener. Thetwo components shall be distinctly pigmented, so thatmixing produces a third color similar to the concrete in thesegments to be joined, and shall be packaged in prepor-tioned, labeled, ready-to-use containers.

Epoxy bonding agents shall be formulated to provideapplication temperature ranges that will permit erection ofmatch cast segments at substrate temperatures from 40°Fto 115°F. If two surfaces to be bonded have different sub-strate temperatures, the adhesive applicable at the lowertemperature shall be used.

Epoxy bonding agents shall be insensitive to dampconditions during application and, after curing, shall ex-hibit high bonding strength to cured concrete, good waterresistivity, low creep characteristics, and tensile strengthgreater than the concrete. In addition, the epoxy bondingagents shall function as a lubricant during the joining ofthe match cast segments, as a filler to accurately match thesurface of the segments being joined, and as a durable,watertight bond at the joint.

Epoxy bonding agents shall be tested to determinetheir workability, gel time, open time, bond and compres-sion strength, shear, and working temperature range. Thefrequency of the tests shall be as stated in the Special Pro-visions of the Contract.

The Contractor shall furnish the Engineer with samplesof the material for quality assurance testing, and a certifi-

cation from a reputable independent laboratory indicatingthat the material has passed the required tests.

Specific properties of epoxy and the test procedures tobe used to measure these properties shall be as describedin the following subarticles.

8.13.7.1.1 Test 1—Sag Flow of Mixed EpoxyBonding Agent

This test measures the application workability of thebonding agent.

Testing Method: ASTM D 2730 for the designated tem-perature range.

Specification: Mixed epoxy bonding agent must notsag flow at 1 ⁄8-inch minimum thickness at the designatedminimum and maximum application temperature rangefor the class of bonding agents used.

8.13.7.1.2 Test 2—Gel Time of Mixed EpoxyBonding Agent

Gel time is determined on samples mixed as specifiedin the testing method. It provides a guide for the period oftime the mixing bonding agent remains workable in themixing container during which it must be applied to thematch-cast joint surfaces.

Testing Method: ASTM D 2471 (except that 1 quartand 1 gallon quantities shall be tested).

Specification: 30 minutes minimum on 1 quart and 1gallon quantities at the maximum temperature of the des-ignated application temperature range. (Note: Gel time isnot to be confused with open time specified in Test 3.)

8.13.7.1.3 Test 3—Open Time of Bonding Agent

This test measures workability of the epoxy bondingagent for the erection and post-tensioning operations. Astested here, open time is defined as the minimum allow-able period of elapsed time from the application of themixed epoxy bonding agent to the precast segments untilthe two segments have been assembled together and tem-porarily post-tensioned.

Testing Method: Open time is determined using testspecimens as detailed in the Tensile Bending Test (Test 4).The epoxy bonding agent, at the highest specified appli-cation temperature, is mixed together and applied as in-structed in Test 4 to the concrete prisms, which shall alsobe at the highest specified application temperature. Theadhesive coated prisms shall be maintained for 60 minutes



at the highest specified application temperature with theadhesive coated surface or surfaces exposed and uncov-ered before joining together. The assembled prisms arethen curved and tested as instructed in Test 4.

Specification: The epoxy bonding agent is acceptablefor the specified application temperature only when es-sentially total fracturing of concrete paste and aggregateoccurs with no evidence of adhesive failure.

Construction situations may sometimes require appli-cation of the epoxy bonding agent to the precast sectionprior to erecting, positioning, and assembling. This oper-ation may require epoxy bonding agents having prolongedopen time. In general, where the erection conditions aresuch that the sections to be bonded are prepositioned priorto epoxy application, the epoxy bonding agent shall havea minimum open time of 60 minutes within the tempera-ture range specified for its application.

8.13.7.1.4 Test 4—Three-Point Tensile Bending Test

This test, performed on a pair of concrete prismsbonded together with epoxy bonding agent, determinesthe bonding strength between the bonding agent and con-crete. The bonded concrete prisms are compared to a ref-erence test beam of concrete 6 � 6 � 18 inches.

Testing Method: 6 � 6 � 9-inch concrete prisms of6,000-psi compressive strength at 28 days shall be sand-blasted on one 6 � 6-inch side to remove mold releaseagent, laitance, etc., and submerged in clean water at thelower temperature of the specified application tempera-ture range for 72 hours. Immediately on removing theconcrete prisms from the water, the sandblasted surfacesshall be air-dried for 1 hour at the same temperature and50% relative humidity and each shall be coated with approximately a 1 ⁄16-inch layer of the mixed bondingagent. The adhesive coated faces of two prisms shallthen be placed together and held with a clamping forcenormal to the bonded interface of 50 psi. The assemblyshall then be wrapped in a damp cloth which is kept wet during the curing period of 24 hours at the lower temperature of the specified application temperaturerange.

After 24 hours curing at the lower temperature of the application temperature range specified for the epoxy bonding agent, the bonded specimen shall be unwrapped, removed from the clamping assembly and immediately tested. The test shall be conducted using the standard AASHTO T 97 (ASTM C 78) test forflexural strength with third point loading and the standardMR unit. At the same time the two prisms are preparedand cured, a companion test beam shall be prepared of the

same concrete, cured for the same period, and tested fol-lowing AASHTO T 97 (ASTM C 78).

Specification: The epoxy bonding agent is acceptableif the load on the prisms at failure is greater than 90% ofthe load on the reference test beam at failure.

8.13.7.1.5 Test 5—Compression Strength of CuredEpoxy Bonding Agent

This test measures the compressive strength of theepoxy bonding agent.

Testing Method: ASTM D 695.

Specification: Compressive strength at 77°F shall be2,000 psi minimum after 24 hours cure at the minimumtemperature of the designated application temperaturerange and 6,000 psi at 48 hours.

8.13.7.1.6 Test 6—Temperature Deflection of EpoxyBonding Agent

This test determines the temperature at which an arbi-trary deflection occurs under arbitrary testing conditionsin the cured epoxy bonding agent. It is a screening test toestablish performance of the bonding agent throughoutthe erection temperature range.

Testing Method: ASTM D 648.

Specification: A minimum deflection temperature of122°F at fiber stress loading of 264 psi is required on testspecimens cured 7 days at 77°F.

8.13.7.1.7 Test 7—Compression and Shear Strengthof Cured Epoxy Bonding Agent

This test is a measure of the compressive strength andshear strength of the epoxy bonding agent compared to theconcrete to which it bonds. The “slant cylinder” specimenwith the epoxy bonding agent is compared to a referencetest cylinder of concrete only.

Testing Method: A test specimen of concrete is pre-pared in a standard 6 � 12-inch cylinder mold to have aheight at midpoint of 6 inches and an upper surface witha 30° slope from the vertical. The upper and lower por-tions of the specimen with the slant surfaces may beformed through the use of an elliptical insert or by saw-ing a full-sized 6 � 12-inch cylinder. If desired, 3 � 6-inch or 4 � 8-inch specimens may be used. After the



specimens have been moist cured for 14 days, the slantsurfaces shall be prepared by light sandblasting, stoning,or acid etching, then washing and drying the surfaces,and finally coating one of the surfaces with a 10-mil.thickness of the epoxy bonding agent under test. Thespecimens shall then be pressed together and held in po-sition for 24 hours. The assembly shall then be wrappedin a damp cloth which shall be kept wet during an addi-tional curing period of 24 hours at the minimum temper-ature of the designated application temperature range.The specimen shall then be tested at 77°F followingAASHTO T 22 (ASTM C 39) procedures. At the sametime as the slant cylinder specimens are made and cured,a companion standard test cylinder of the same concreteshall be made, cured for the same period, and tested fol-lowing AASHTO T 22 (ASTM C 39).

Specification: The epoxy bonding agent is acceptablefor the designated application temperature range if theload on the slant cylinder specimen is greater than 90% ofthe load on the companion cylinder.

8.13.7.2 Mixing and Installation of Epoxy

Instructions furnished by the supplier for the safe stor-age, mixing, and handling of the epoxy bonding agentshall be followed. The epoxy shall be thoroughly mixeduntil it is of uniform color. Use of a proper-sized mechan-ical mixer operating at no more than 600 RPM will be re-quired. Contents of damaged or previously opened con-tainers shall not be used.

Surfaces to which the epoxy material is to be appliedshall be at least 40°F and shall be free from oil, laitance,form release agent, or any other material that would pre-vent the epoxy from bonding to the concrete surface. Alllaitance and other contaminants shall be removed by lightsandblasting or by high pressure water blasting with aminimum pressure of 5,000 psi. Wet surfaces shall bedried before applying epoxy bonding agents. The surfaceshall be at least the equivalent of saturated surface dry (novisible water).

Mixing shall not start until the segment is prepared forinstallation. Application of the mixed epoxy bondingagent shall be according to the manufacturer’s instruc-tions using trowel, rubber glove, or brush on one or bothsurfaces to be joined. The coating shall be smooth anduniform and shall cover the entire surface with a mini-mum thickness of 1 ⁄16 inch applied on both surfaces or 1⁄ 8

inch if applied on one surface. Epoxy should not beplaced within 3 ⁄8 inch of prestressing ducts to minimizeflow into the ducts. A discernible bead line must beobserved on all exposed contact areas after temporarypost-tensioning. Erection operations shall be coordinatedand conducted so as to complete the operations of apply-

ing the epoxy bonding agent to the segments, erection,assembling, and temporary post-tensioning of the newlyjoined segment within 70% of the open time period of thebonding agent.

The epoxy material shall be applied to all surfaces tobe joined within the first half of the gel time, as shown onthe containers. The segments shall be joined within 45minutes after application of the first epoxy material placedand a minimum average temporary prestress of 40 psiover the cross section should be applied within 70% of theopen time of the epoxy material. At no point of the crosssection shall the temporary prestress be less than 30 psi.

The joint shall be checked immediately after erectionto verify uniform joint width and proper fit. Excess epoxyfrom the joint shall be removed where accessible. All ten-don ducts shall be swabbed immediately after stressing,while the epoxy is still in the nongelled condition, to re-move or smooth out any epoxy in the conduit and to sealany pockets or air bubble holes that have formed at thejoint.

If the jointing is not completed within 70% of the opentime, the operation shall be terminated and the epoxybonding agent shall be completely removed from the sur-faces. The surfaces must be prepared again and freshepoxy shall be applied to the surface before resumingjointing operations.

As general instructions cannot cover all situations, spe-cific recommendations and instructions shall be obtainedin each case from the Engineer in charge.

8.14 MORTAR AND GROUT

8.14.1 General

This work consists of the making and placing of mor-tar and grout for use in concrete structures other than inprestressing ducts. Such uses include mortar for fillingunder masonry plates and for filling keyways betweenprecast members where shown on the plans, mortar usedto fill voids and repair surface defects, grout used to fillsleeves for anchor bolts, and mortar and grout for othersuch uses where required or approved.

8.14.2 Materials and Mixing

Materials for mortar and grout shall conform to the re-quirements of Article 8.3. The grading of sand for use ingrout or for use in mortar when the width or depth of thevoid to be filled is less than 3 ⁄4 inch shall be modified sothat all material passes the No. 8 sieve.

Type 1A, air entraining, Portland cement shall be usedwhen air entrainment is required for the concrete againstwhich the grout or mortar is to be placed.



Unless otherwise specified or ordered by the Engineer,the proportion of cement to sand for mortar shall be oneto two and for grout shall be one to one. Proportioningshall be by loose volume.

When nonshrink mortar or grout is specified, either anonshrink admixture or an expansive hydraulic cementconforming to ASTM C 845 of a type approved by the En-gineer, shall be used.

Only sufficient water shall be used to permit placingand packing. For mortar, only enough water shall be usedso that the mortar will form a ball when squeezed gentlyin the hand.

Mixing shall be done by either hand methods or with rotating paddle-type mixing machines and shall be continued until all ingredients are thoroughly mixed. Once mixed, mortar or grout shall not beretempered by the addition of water and shall be placedwithin 1 hour.

8.14.3 Placing and Curing

Concrete areas to be in contact with the mortar or groutshall be cleaned of all loose or foreign material that wouldin any way prevent bond and the concrete surfaces andshall be flushed with water and allowed to dry to a surfacedry condition immediately prior to placing the mortar orgrout.

The mortar or grout shall completely fill and shall betightly packed into recesses and holes, on surfaces, understructural members, and at other locations specified. Afterplacing, all surfaces of mortar or grout shall be cured bythe water method as provided in Article 8.11 for a periodof not less than 3 days.

Keyways, spaces between structural members, holes,spaces under structural members, and other locationswhere mortar could escape shall be mortar-tight beforeplacing mortar.

No load shall be allowed on mortar that has been inplace less than 72 hours, unless otherwise permitted bythe Engineer.

All improperly cured or otherwise defective mortar orgrout shall be removed and replaced by the Contractor atown expense.

8.15 APPLICATION OF LOADS

8.15.1 General

Loads shall not be applied to concrete structures untilthe concrete has attained sufficient strength and, when ap-plicable, sufficient prestressing has been completed, sothat damage will not occur.

8.15.2 Earth Loads

Whenever possible the sequence of placing backfillaround structures shall be such that overturning or slidingforces are minimized. When the placement of backfill willcause flexural stresses in the concrete, and unless other-wise permitted by the Engineer, the placement shall notbegin until the concrete has reached not less than 80% ofits specified strength.

8.15.3 Construction Loads

Light materials and equipment may be carried onbridge decks only after the concrete has been in place atleast 24 hours, providing curing is not interfered with andthe surface texture is not damaged. Vehicles needed forconstruction activities and weighing between 1,000 and4,000 pounds, and comparable materials and equipmentloads, will be allowed on any span only after the lastplaced deck concrete has attained a compressive strengthof at least 2,400 pounds per square inch. Loads in excessof the above shall not be carried on bridge decks until thedeck concrete has reached its specified strength. In addi-tion, for post-tensioned structures, vehicles weighing over4,500 pounds, and comparable materials and equipmentloads, will not be allowed on any span until the prestress-ing steel for that span has been tensioned.

Precast concrete or steel girders shall not be placed onsubstructure elements until the substructure concrete hasattained 70% of its specified strength.

Otherwise, loads imposed on existing, new or partiallycompleted portions of structures due to construction oper-ations shall not exceed the load-carrying capacity of thestructure, or portion of structure, as determined by the LoadFactor Design methods of AASHTO using Load Group IB.The compressive strength of concrete (fc�) to be used incomputing the load-carrying capacity shall be the smallerof the actual compressive strength at the time of loading orthe specified compressive strength of the concrete.

8.15.4 Traffic Loads

Traffic will not be permitted on concrete decks until atleast 14 days after the last placement of deck concrete anduntil such concrete has attained its specified strength.


8.16.1 Measurement

Except for concrete in components of the work forwhich payment is made under other bid items, all concretefor structures will be measured by either the cubic yard foreach class of concrete included in the schedule of bid



items or by the unit for each type of precast concretemember listed in the schedule of bid items.

When measured by the cubic yard, the quantity of con-crete will be computed from the dimensions shown on theplans or authorized in writing by the Engineer with thefollowing exceptions:

The quantity of concrete involved in fillets, scoringsand chamfers 1 square inch or less in cross-sec-tional area will not be included or deducted.

Deductions for the volume of concrete displaced byconcrete and timber piles embedded in the concretewill be made. Deductions for other embeddedmaterials including reinforcing, structural and pre-stressing steel, expansion joint filler material, waterstops and deck drains will not be made. Thevolume of timber piles will be assumed to be 0.8cubic foot per linear foot of pile.

When there is a bid item for concrete to be used as aseal course in cofferdams, the quantity of such con-crete to be paid for shall include the actual volumeof concrete seal course in place, but in no case shallthe total volume to be paid for exceed the cubicalcontents contained between the vertical surfaces 1foot outside the neat lines of the seal course asshown on the plans. The thickness of seal course tobe paid for shall be the thickness shown on theplans or ordered in writing by the Engineer.

The number of precast concrete members of each typelisted in the schedule of bid items will be the number ofacceptable members of each type furnished and installedin the work.

Expansion joint armor assemblies will be measuredand paid for as provided for in Section 23, “MiscellaneousMetal.”

Whenever an alternative or option is shown on theplans or permitted by the specifications, the quantities ofconcrete will be computed on the basis of the dimensionsshown on the plans and no change in quantities measuredfor payment will be made because of the use by the Con-tractor of such alternatives or options.

8.16.2 Payment

The cubic yards of concrete and the number of precastconcrete members, as measured above for each type orclass listed in the schedule of bid items, will be paid for atthe contract prices per cubic yard or the contract prices pereach member.

Payment for concrete of the various classes and forprecast concrete members of the various types shall beconsidered to be full compensation for the cost offurnishing all labor, materials, equipment, and incidentals,and for doing all the work involved in constructing the concrete work complete in place, as shown on theplans and specified. Such payment includes full com-pensation for furnishing and placing expansion jointfillers, sealed joints, waterstops, drains, vents, miscella-neous metal devices and the drilling of holes for dowelsand the grouting of dowels in drilled holes, unlesspayment for such work is specified to be included in an-other bid item.

In addition, payment for precast concrete membersshall be considered to be full compensation for the cost ofall reinforcing steel, prestressing materials and otheritems embedded in the member, and for the erection of themembers.



Section 9REINFORCING STEEL

9.1 DESCRIPTION

This work shall consist of furnishing and placing rein-forcing steel in accordance with these Specifications andin conformity with the plans.

9.2 MATERIAL

All reinforcing bars shall be deformed except that plainbars may be used for spirals and ties.

Reinforcing steel shall conform to the requirements ofthe following specifications.

9.2.1 Uncoated Reinforcing Steel

Deformed and Plain Billet-Steel Bars for Concrete Re-inforcement—AASHTO M 31 (ASTM A 615). Grade 60shall be used unless otherwise shown or specified.

Low-Alloy Steel Deformed and Plain Bars for Con-crete Reinforcement—ASTM A 706.

Rail-Steel Deformed and Plain Bars for Concrete Re-inforcement—AASHTO M 42 including SupplementaryRequirement S1 (ASTM A 616 including SupplementaryRequirement S1). Grade 60 steel shall be used unless oth-erwise shown or specified.

Deformed Steel Wire for Concrete Reinforcement—AASHTO M 225 (ASTM A 496).

Welded Plain Steel Wire Fabric for Concrete Rein-forcement—AASHTO M 55 (ASTM A 185).

Plain Steel Wire for Concrete Reinforcement—AASHTO M 32 (ASTM A 82).

Welded Deformed Steel Wire Fabric for Concrete Re-inforcement—AASHTO M 221 (ASTM A 497).

9.2.2 Epoxy-Coated Reinforcing Steel

The reinforcing steel to be epoxy coated shall conformto Article 9.2.1.

When epoxy coating of reinforcing bars is required, thecoating materials and process, the fabrication, handling,identification of the bars, and the repair of damaged coat-ing material that occurs during fabrication and handling to

the point of shipment to the jobsite shall conform to therequirements of AASHTO M 284 (ASTM D 3963) orASTM A 934, as specified in the contract documents.

Epoxy-coated reinforcing bars shall be coated in a cer-tified epoxy coating applicator plant in accordance withthe Concrete Reinforcing Steel Institute’s Voluntary Cer-tification Program for Fusion-Bonded Epoxy Coated Ap-plicator Plants, or equivalent.

Epoxy-coated steel wire and welded wire fabric for re-inforcement shall conform to the requirements of ASTMA 884, Class A.

Each shipment of epoxy-coated reinforcing steel shallbe accompanied with a Certificate of Compliance signedby the applicator of the coating certifying that the epoxy-coated reinforcing bars conform to the requirements ofAASHTO M 284 or ASTM A 934 or that the epoxy-coated wire or welded wire fabric conforms to ASTM A884, Class A.

9.2.3 Stainless Steel Reinforcing Bars

When required by the contract documents, deformedor plain stainless steel reinforcing bars shall conform tothe requirements of ASTM A 955 M.

9.2.4 Mill Test Reports

Whenever steel reinforcing bars, other than bars con-forming to ASTM A 706, are to be spliced by welding orwhen otherwise requested, a certified copy of the mill testreport showing physical and chemical analysis for eachheat or lot of reinforcing bars delivered shall be providedto the Engineer.

9.3 BAR LISTS AND BENDING DIAGRAMS

When the plans do not include detailed bar lists andbending diagrams, the Contractor shall provide such listsand diagrams to the Engineer for review and approval.Fabrication of material shall not begin until such lists havebeen approved. The approval of bar lists and bending dia-grams shall in no way relieve the Contractor of responsi-

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bility for the correctness of such lists and diagrams. Anyexpense incident to the revision of material furnished inaccordance with such lists and diagrams to make it com-ply with the design drawings shall be borne by the Con-tractor.

9.4 FABRICATION

9.4.1 Bending

Bar reinforcement shall be cut and bent to the shapesshown on the plans. Fabrication tolerances shall be in ac-cordance with ACI 315. All bars shall be bent cold, unlessotherwise permitted. Bars partially embedded in concreteshall not be field bent except as shown on the plans orspecifically permitted.

9.4.2 Hooks and Bend Dimensions

The dimensions of hooks and the diameters of bendsmeasured on the inside of the bar shall be as shown on theplans. When the dimensions of hooks or the diameter ofbends are not shown, they shall be in accordance with Di-vision I, Article 8.23 or ACI 318, “Building Code Re-quirements for Reinforced Concrete.”

9.4.3 Identification

Bar reinforcement shall be shipped in standard bundles,tagged and marked in accordance with the Manual of Stan-dard Practice of the Concrete Reinforcing Steel Institute.

9.5 HANDLING, STORING, AND SURFACECONDITION OF REINFORCEMENT

Steel reinforcement shall be stored above the surfaceof the ground on platforms, skids, or other supports andshall be protected from mechanical injury and surface de-terioration caused by exposure to conditions producingrust. When placed in the work, reinforcement shall be freefrom dirt, loose rust or scale, mortar, paint, grease, oil, orother nonmetallic coatings that reduce bond. Epoxy coat-ings of reinforcing steel in accord with standards in thisarticle shall be permitted. Reinforcement shall be freefrom injurious defects such as cracks and laminations.Bonded rust, surface seams, surface irregularities, or millscale will not be cause for rejection, provided the mini-mum dimensions, cross-sectional area, and tensile prop-erties of a hand wire brushed specimen meet the physicalrequirements for the size and grade of steel specified.

Epoxy-coated reinforcing steel shall be handled andstored by methods that will not damage the epoxy coat-

ing. All systems for handling epoxy-coated reinforce-ment bars shall have adequately padded contact areas. Allbundling bands shall be padded and all bundles shall belifted with a strong back, multiple supports, or platformbridge so as to prevent bar-to-bar abrasion from sags inthe bundle. Bars or bundles shall not be dropped ordragged. Epoxy-coated reinforcing steel shall be storedon wooden or padded supports.

Epoxy-coated reinforcing steel shall be protected fromsunlight, salt spray, and weather exposure. Provisionsshall be made for air circulation around the coated rein-forcement to minimize condensation under the protectivecovering.

9.6 PLACING AND FASTENING

9.6.1 General

Steel reinforcement shall be accurately placed asshown on the plans and firmly held in position during theplacing and consolidation of concrete. Bars shall be tiedat all intersections around the perimeter of each mat andat not less than 2-foot centers or at every intersection,whichever is greater, elsewhere. Bundled bars shall betied together at not more than 6-foot centers. For fasten-ing epoxy-coated reinforcement, tie wire and metal clipsshall be plastic-coated or epoxy-coated. If uncoatedwelded wire fabric is shipped in rolls, it shall be straight-ened into flat sheets before being placed. Welding ofcrossing bars (tack welding) will not be permitted for as-sembly of reinforcement unless authorized in writing bythe Engineer.

9.6.2 Support Systems

Reinforcing steel shall be supported in its proper posi-tion by use of precast concrete blocks, wire bar supports,supplementary bars or other approved devices. Such rein-forcement supports or devices shall be of such height andplaced at sufficiently frequent intervals so as to maintainthe distance between the reinforcing steel and the formedsurface or the top surface of deck slabs within 1⁄ 4 inch ofthat indicated on the plans.

Platforms for the support of workers and equipmentduring concrete placement shall be supported directly onthe forms and not on the reinforcing steel.

9.6.3 Precast Concrete Blocks

Precast concrete blocks shall have a compressivestrength not less than that of the concrete in which they



are to be embedded. The face of blocks in contact withforms for exposed surfaces shall not exceed 2 inches by2 inches in size and shall have a color and texture thatwill match the concrete surface. When used on vertical orsloping surfaces, such blocks shall have an embeddedwire for securing the block to the reinforcing steel. Whenused in slabs, either such a tie wire or, when the weightof the reinforcing steel is sufficient to firmly hold theblocks in place, a groove in the top of the block may be used. For epoxy-coated bars, such tie wires shall be plastic-coated or epoxy-coated.

9.6.4 Wire Bar Supports

Wire bar supports, such as ferrous metal chairs andbolsters, shall conform to industry practice as describedin the Manual of Standard Practice of the Concrete Re-inforcing Steel Institute. Such chairs or bolsters whichbear against the forms for exposed surfaces shall be ei-ther Class 1—Maximum Protection (Plastic Protected) orClass 2, Type B-Moderate Protection (Stainless SteelTipped) for which the stainless steel conforms to ASTMA 493, Type 430. For epoxy-coated reinforcement, allwire bar supports and bar clips shall be plastic-coated orepoxy-coated.

9.6.5 Adjustments

Nonprestressed reinforcement used in post-tensionedconcrete shall be adjusted or relocated during the installa-tion of prestressing ducts or tendons, as required to pro-vide planned clearances to the prestressing tendons, an-chorages and stressing equipment, as approved by theEngineer.

9.6.6 Repair of Damaged Epoxy Coating

In addition to the requirements of Article 9.2.2, dam-aged coating on epoxy-coated reinforcing steel that oc-curs during shipment, handling and placement of the re-inforcing steel shall be repaired. The maximum amountof repaired damaged areas shall not exceed 2% of the sur-face area in any linear foot of each bar. Should theamount of damaged coating incurred during shipment,handling and placing exceed 2% of the surface area inany linear foot of each bar, that bar shall be removed andreplaced with an acceptable epoxy-coated bar. The sumof the areas covered with patching material applied dur-ing repairs at all stages of the work shall not exceed 5%of the total surface area of any bar. The patching materialshall be prequalified as required for the coating materialand shall be either identified on the container as meetingthe requirements of Annex A1 of AASHTO M 284 or

Annex A1 of ASTM A 934, or shall be accompanied by aCertificate of Compliance certifying that the materialmeets the requirements of said Annexes A1. Patching ofdamaged areas shall be performed in accordance with thepatching material manufacturer’s recommendations.Patches shall be allowed to cure before placing concreteover the coated bars.

9.7 SPLICING OF BARS

9.7.1 General

All reinforcement shall be furnished in the full lengthsindicated on the plans unless otherwise permitted. Exceptfor splices shown on the plans and lap splices for No. 5 orsmaller bars, splicing of bars will not be permitted with-out written approval. Splices shall be staggered as far aspossible.

9.7.2 Lap Splices

Lap splices shall be of the lengths shown on the plans.If not shown on the plans, the length of lap splices shallbe in accordance with Division I, Article 8.32, or as ap-proved by the Engineer.

In lap splices, the bars shall be placed and tied in sucha manner as to maintain the minimum distance to the sur-face of the concrete shown on the plans. Lap splices shallnot be used for Nos. 14 and 18 bars except as provided inDivision I, Articles 4.4.11.5.7 and 8.32.4.1.

9.7.3 Welded Splices

Welded splices of reinforcing bars shall be used only ifdetailed on the plans or if authorization is made by the En-gineer in writing. Welding shall conform to the StructuralWelding Code, Reinforcing Steel, ANSI AWS D1.4 of theAmerican Welding Society and applicable special provi-sions in the contract documents.

Welded splices shall not be used on epoxy-coated bars.To avoid heating of the coating, no welding shall be per-formed in close proximity to epoxy-coated bars.

9.7.4 Mechanical Splices

Mechanical splices shall be used only if preapprovedor detailed on the plans or authorized in writing by the En-gineer. Such mechanical splices shall develop in tensionor compression, as required, at least 125% of the specifiedyield strength of the bars being spliced.

When requested by the Engineer, up to two fieldsplices out of each 100, or portion thereof, placed in the



work and chosen at random by the Engineer, shall be re-moved by the Contractor and tested by the Engineer forcompliance to 125% of the specified yield strength of thebars being spliced.

9.8 SPLICING OF WELDED WIRE FABRIC

Sheets of welded wire fabric shall be spliced by over-lapping each other sufficiently to maintain a uniformstrength and shall be securely fastened at the ends andedges. The edge lap shall not be less than one mesh inwidth plus 2 inches.

9.9 SUBSTITUTIONS

Substitution of different size reinforcing bars will bepermitted only when authorized by the Engineer. The sub-stituted bars shall have an area equivalent to the designarea, or larger, and shall conform to the requirements ofDivision I, Article 8.16.8.4.

9.10 MEASUREMENT

Steel reinforcement incorporated in the concrete willbe measured in pounds based on the total computedweight for the sizes and lengths of bars, wire or weldedwire fabric shown on the plans or authorized for use in thework.

The weight of bars will be computed using the follow-ing weights:

Bar Size Weight lbs. per lin. feet

No. 3 0.376No. 4 0.668No. 5 1.043No. 6 1.502No. 7 2.044No. 8 2.670No. 9 3.400No. 10 4.303No. 11 5.313No. 14 7.65No. 18 13.60

The weight of wire, welded wire fabric and plain barsof sizes other than those listed above, will be computedfrom tables of weights published by CRSI or computedusing nominal dimensions and an assumed unit weight of0.2833-pound per cubic inch. The cross-sectional area ofwire in hundredths of square inches will be assumed to beequal to its W or D-Size Number. If the weight per squarefoot of welded wire fabric is given on the plans, thatweight will be used.

The weight of reinforcement used in items such as rail-ings and precast members, where payment for the rein-forcement is included in the contract price for the item,will not be included. Threaded bars or dowels placed afterthe installation of precast members in the work and usedto attach such members to cast-in-place concrete will beincluded.

No allowance will be made for clips, wire, separators,wire chairs, and other material used in fastening the rein-forcement in place. If bars are substituted upon the Con-tractor’s request and as a result more reinforcing steel isused than specified, only the amount specified will be included.

The additional reinforcing steel required for splicesthat are not shown on the plans but are authorized as pro-vided herein, will not be included.

No allowance will be made for the weight of epoxycoating in computing the weight of epoxy-coated rein-forcing steel.

9.11 PAYMENT

Payment for the quantity of reinforcement determinedunder measurement for each class of reinforcing steelshown in the bid schedule will be made at the contractprice per pound. Payment shall be considered to be fullcompensation for furnishing, fabricating, splicing, andplacing of the reinforcing steel including all incidentalwork and materials required.



Section 10PRESTRESSING

10.1 GENERAL

10.1.1 Description

This work shall consist of prestressing precast or cast-in-place concrete by furnishing, placing, and tensioning ofprestressing steel in accordance with details shown on theplans, and as specified in these specifications and the spe-cial provisions. It includes prestressing by either the pre-tensioning or post-tensioning methods or by a combina-tion of these methods.

This work shall include the furnishing and installationof any appurtenant items necessary for the particular pre-stressing system to be used, including but not limited toducts, anchorage assemblies and grout used for pressuregrouting ducts.

For cast-in-place prestressed concrete, the term “mem-ber” as used in this section shall be considered to mean theconcrete which is to be prestressed.

When members are to be constructed with part of thereinforcement pretensioned and part post-tensioned, theapplicable requirement of this Specification shall apply toeach method.

10.1.2 Details of Design

When the design for the prestressing work is not fullydetailed on the plans, the Contractor shall determine thedetails or type of prestressing system for use and selectmaterials and details conforming to these Specificationsas needed to satisfy the prestressing requirements speci-fied. The system selected shall provide the magnitude anddistribution of prestressing force and ultimate strength re-quired by the plans without exceeding allowable tempo-rary stresses. Unless otherwise shown on the plans, all de-sign procedures, coefficients and allowable stresses,friction and prestress losses as well as tendon spacing andclearances shall be in accordance with the Division I, De-sign, of the AASHTO Standard Specifications for High-way Bridges.

The prestressing may be performed by either preten-sioning or post-tensioning methods unless the plans show

only pretensioning details. If the plans show only preten-sioning details, the use of a post-tensioning system will beallowed only if complete details of any necessary modifi-cations are approved by the Engineer.

When the effective or working force or stress is shown on the plans, it shall be considered to be the forceor stress remaining in the prestressing steel after all losses,including creep and shrinkage of concrete, elastic short-ening of concrete, relaxation of steel, friction and take upor seating of anchorages, and all other losses peculiar tothe method or system of prestressing have taken place orhave been provided for. When the jacking force is shownon the plans, it shall be considered to be the force appliedto the tendon prior to anchorage and the occurrence of anylosses, including the anchor set loss.

10.2 SUPPLEMENTARY DRAWINGS


Whenever the plans do not include complete details fora prestressing system and its method of installation, orwhen complete details are provided in the plans and theContractor wishes to propose any change, the Contractorshall prepare and submit to the Engineer working draw-ings of the prestressing system proposed for use. Fabrica-tion or installation of prestressing material shall not beginuntil the Engineer has approved the drawings.

The working drawings of the prestressing system shallshow complete details and substantiating calculations ofthe method, materials and equipment the Contractor pro-poses to use in the prestressing operations, including anyadditions or rearrangement of reinforcing steel and any re-vision in concrete dimensions from that shown on theplans. Such details shall outline the method and sequenceof stressing and shall include complete specifications anddetails of the prestressing steel and anchoring devices,working stresses, anchoring stresses, tendon elongations,type of ducts, and all other data pertaining to the pre-stressing operation, including the proposed arrangementof the prestressing steel in the members.

Working drawings shall be submitted sufficiently inadvance of the start of the affected work to allow time for

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review by the Engineer and correction by the Contractorof the drawings without delaying the work.

10.2.2 Composite Placing Drawings

When required by the special provisions, in additionto all required working drawings, the Contractor shallprepare composite placing drawings to scale and in suf-ficient detail to show the relative positions of all itemsthat are to be embedded in the concrete, and their em-bedment depth, for the portions of the structure that areto be prestressed. Such embedded items include the pre-stressing ducts, vents, anchorage reinforcement and hard-ware, reinforcing steel, anchor bolts, earthquake restrain-ers, deck joint seal assemblies, drainage systems, utilityconduits and other such items. Such drawings shall be ad-equate to ensure that there will be no conflict between theplanned positions of any embedded items and that con-crete cover will be adequate. If during the preparation ofsuch drawings conflicts are discovered, the Contractorshall revise his or her working drawing for one or moreof the embedded items or propose changes in the dimen-sions of the work as necessary to eliminate the conflictsor provide proper cover. Any such revisions shall be ap-proved by the Engineer before work on any affected itemis started.

All costs involved with the preparation of suchdrawings and with making the necessary modifications to the work resulting therefrom shall be borne by theContractor.

10.3 MATERIALS

10.3.1 Prestressing Steel and Anchorages

Prestressing reinforcement shall be high-strengthseven-wire strand, high-strength steel wire, or high-strength alloy bars of the grade and type called for on theplans or in the special provisions and shall conform to therequirements of the following specifications.

10.3.1.1 Strand

Uncoated seven-wire strand shall conform to therequirements of AASHTO M 203 (ASTM A 416).Supplement S1 (Low-Relaxation) shall apply whenspecified.

10.3.1.2 Wire

Uncoated stress-relieved steel wire shall conform tothe requirements of AASHTO M 204 (ASTM A 421).

10.3.1.3 Bars

Uncoated high-strength bars shall conform to the re-quirements of AASHTO M 275 (ASTM A 722). Bars withgreater minimum ultimate strength, but otherwise pro-duced and tested in accordance with AASHTO M 275(ASTM A 722), may be used provided they have no prop-erties that make them less satisfactory than the specifiedmaterial.

10.3.2 Post-Tensioning Anchorages and Couplers

All anchorages and couplers shall develop at least 95%of the actual ultimate strength of the prestressing steel,when tested in an unbonded state, without exceeding an-ticipated set. The coupling of tendons shall not reduce theelongation at rupture below the requirements of the ten-don itself. Couplers and/or coupler components shall beenclosed in housings long enough to permit the necessarymovements. Couplers for tendons shall be used only at lo-cations specifically indicated and/or approved by the En-gineer. Couplers shall not be used at points of sharp ten-don curvature.

10.3.2.1 Bonded Systems

Bond transfer lengths between anchorages and thezone where full prestressing force is required under ser-vice and ultimate loads shall normally be sufficient to de-velop the minimum specified ultimate strength of the pre-stressing steel. When anchorages or couplers are locatedat critical sections under ultimate load, the ultimatestrength required of the bonded tendons shall not exceedthe ultimate capacity of the tendon assembly, includingthe anchorage or coupler, tested in an unbonded state.

Housings shall be designed so that complete groutingof all of the coupler components will be accomplishedduring grouting of tendons.

10.3.2.2 Unbonded Systems

For unbonded tendons, a dynamic test shall be per-formed on a representative anchorage and coupler speci-men and the tendon shall withstand, without failure,500,000 cycles from 60% to 66% of its minimum specifiedultimate strength, and also 50 cycles from 40% to 80% ofits minimum specified ultimate strength. The period ofeach cycle involves the change from the lower stress levelto the upper stress level and back to the lower. The speci-men used for the second dynamic test need not be the sameused for the first dynamic test. Systems utilizing multiplestrands, wires, or bars may be tested utilizing a test tendonof smaller capacity than the full-sized tendon. The test ten-



don shall duplicate the behavior of the full-sized tendonand generally shall not have less than 10% of the capacityof the full-sized tendon. Dynamic tests are not required onbonded tendons, unless the anchorage is located or used insuch manner that repeated load applications can be ex-pected on the anchorage.

Anchorages for unbonded tendons shall not cause a re-duction in the total elongation under ultimate load of thetendon to less than 2% measured in a minimum gaugelength of 10 feet.

All the coupling components shall be completely pro-tected with a coating material prior to final encasement inconcrete.

10.3.2.3 Special Anchorage Device Acceptance Test

10.3.2.3.1 The test block shall be a rectangularprism. It shall contain those anchorage components whichwill also be embedded in the structure’s concrete. Theirarrangement has to comply with the practical applicationand the suppliers specifications. The test block shall con-tain an empty duct of size appropriate for the maximumtendon size which can be accommodated by the anchor-age device.

10.3.2.3.2 The dimensions of the test block perpen-dicular to the tendon in each direction shall be the smallerof the minimum edge distance or the minimum spacingspecified by the anchorage device supplier, with the stip-ulation that the cover over any confining reinforcing steelor supplementary skin reinforcement be appropriate forthe particular application and environment. The length ofthe block along the axis of the tendon shall be at least twotimes the larger of the cross-section dimensions.

10.3.2.3.3 The confining reinforcing steel in the localzone shall be the same as that specified by the anchoragedevice supplier for the particular system.

10.3.2.3.4 In addition to the anchorage device and itsspecified confining reinforcement steel, supplementaryskin reinforcement may be provided throughout the spec-imen. This supplementary skin reinforcement shall bespecified by the anchorage device supplier but shall notexceed a volumetric ratio of 0.01.

10.3.2.3.5 The concrete strength at the time of stress-ing shall be greater than the concrete strength of the testspecimen at time of testing.

10.3.2.3.6 Either of three test procedures is ac-ceptable: cyclic loading described in Article 10.3.2.3.7,

sustained loading described in Article 10.3.2.3.8, ormonotonic loading described in Article 10.3.2.3.9. Theloads specified for the tests are given in fractions of the ultimate load Fpu of the largest tendon that theanchorage device is designed to accommodate. Thespecimen shall be loaded in accordance with normalusage of the device in post-tensioning applications exceptthat load can be applied directly to the wedge plate orequivalent area.

10.3.2.3.7 Cyclic Loading Test

10.3.2.3.7.1 In a cyclic loading test, the load shall beincreased to 0.8Fpu. The load shall then be cycled between0.1Fpu and 0.8Fpu until crack widths stabilize, but for notless than 10 cycles. Crack widths are considered stabilizedif they do not change by more than 0.001 inch over the lastthree readings. Upon completion of the cyclic loading thespecimen shall be preferably loaded to failure or, if lim-ited by the capacity of the loading equipment, to at least1.1Fpu.

10.3.2.3.7.2 Crack widths and crack patterns shall berecorded at the initial load of 0.8Fpu, at least at the lastthree consecutive peak loadings before termination of thecyclic loading, and at 0.9Fpu. The maximum load shallalso be reported.

10.3.2.3.8 Sustained Loading Test

10.3.2.3.8.1 In a sustained loading test, the load shallbe increased to 0.8Fpu and held constant until crack widthsstabilize but for not less than 48 hours. Crack widths areconsidered stabilized if they do not change by more than0.001 inch over the last three readings. After sustainedloading is completed, the specimen shall be preferablyloaded to failure or, if limited by the capacity of the load-ing equipment, to at least 1.1Fpu.

10.3.2.3.8.2 Crack widths and crack patterns shall berecorded at the initial load of 0.8Fpu, at least three times atintervals of not less than 4 hours during the last 12 hoursbefore termination of the sustained loading, and duringloading to failure at 0.9Fpu. The maximum load shall alsobe reported.

10.3.2.3.9 Monotonic Loading Test

10.3.2.3.9.1 In a monotonic loading test, the loadshall be increased to 0.9Fpu and held constant for 1 hour.The specimen shall then be preferably loaded to failure or,



if limited by the capacity of the loading equipment, to atleast 1.2Fpu.

10.3.2.3.9.2 Crack widths and crack patterns shall berecorded at 0.9Fpu after the 1-hour period, and at 1.0Fpu.The maximum load shall also be reported.

10.3.2.3.10 The strength of the anchorage zone mustexceed:

Specimens tested under cyclic or sustained loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..1Fpu

Specimens tested under monotonic loading . . . . . .1.2Fpu

The maximum crack width criteria specified below mustbe met for moderately aggressive environments. Forhigher aggressivity environments the crack width criteriashall be reduced by at least 50%.

(1) No cracks greater than 0.010 inch at 0.8Fpu

after completion of the cyclic or sustained loading, or at 0.9Fpu after the 1-hour period for monotonicloading.(2) No cracks greater than 0.016 inch at 0.9Fpu for cyclic or sustained loading, or at 1.0Fpu for monotonicloading.

10.3.2.3.11 A test series shall consist of three testspecimens. Each one of the tested specimens must meetthe acceptance criteria. If one of the three specimens failsto pass the test, a supplementary test of three additionalspecimens is allowed. The three additional test specimenresults must meet all acceptance criteria of Article10.3.2.3.10.

For a series of similar special anchorage devices, testsare only required for representative samples unless testsfor each capacity of the anchorages in the series are re-quired by the engineer-of-record.

10.3.2.3.12 Records of the anchorage device accep-tance test shall include:

(1) Dimensions of the test specimen.(2) Drawings and dimensions of the anchorage device,including all confining reinforcing steel.(3) Amount and arrangement of supplementary skinreinforcement.(4) Type and yield strength of reinforcing steel.(5) Type and compressive strength at time of testing ofconcrete.(6) Type of testing procedure and all measurementsrequired in Articles 10.3.2.3.7 through 10.3.2.3.10 foreach specimen.

10.4 PLACEMENT OF DUCTS, STEEL, ANDANCHORAGE HARDWARE

10.4.1 Placement of Ducts

Ducts shall be rigidly supported at the proper locationsin the forms by ties to reinforcing steel which are adequateto prevent displacement during concrete placement. Sup-plementary support bars shall be used where needed tomaintain proper alignment of the duct. Hold-down ties tothe forms shall be used when the buoyancy of the ducts inthe fluid concrete would lift the reinforcing steel.

Joints between sections of duct shall be coupled withpositive connections which do not result in angle changesat the joints and will prevent the intrusion of cement paste.

After placing of ducts, reinforcement and forming iscomplete, an inspection shall be made to locate possibleduct damage.

All unintentional holes or openings in the duct must berepaired prior to concrete placing.

Grout openings and vents must be securely anchoredto the duct and to either the forms or to reinforcing steelto prevent displacement during concrete placing opera-tions.

After installation in the forms, the ends of ducts shallat all times be covered as necessary to prevent the entry ofwater or debris.

10.4.1.1 Vents and Drains

All ducts for continuous structures shall be vented atthe high points of the duct profile, except where the cur-vature is small, as in continuous slabs, and at additionallocations as shown on the plans. Where freezing condi-tions can be anticipated prior to grouting, drains shall beinstalled at low point in ducts where needed to prevent theaccumulation of water. Low-point drains shall remainopen until grouting is started.

The ends of vents and drains shall be removed 1 inchbelow the surface of the concrete after grouting has beencompleted, and the void filled with mortar.

10.4.2 Placement of Prestressing Steel

10.4.2.1 Placement for Pretensioning

Prestressing steel shall be accurately installed in theforms and held in place by the stressing jack or temporaryanchors and, when tendons are to be draped, by hold-down devices. The hold-down devices used at all pointsof change in slope of tendon trajectory shall be of an ap-proved low-friction type.

Prestressing steel shall not be removed from its pro-tective packaging until immediately prior to installation in

556 HIGHWAY BRIDGES 10.3.2.3.9.1


the forms and placement of concrete. Openings in thepackaging shall be resealed as necessary to protect the un-used steel. While exposed, the steel shall be protected asneeded to prevent corrosion.

10.4.2.2 Placement for Post-Tensioning

All prestressing steel preassembled in ducts and in-stalled prior to the placement of concrete shall be accu-rately placed and held in position during concrete place-ment.

When the prestressing steel is installed after theconcrete has been placed, the Contractor shall demon-strate to the satisfaction of the Engineer that the ducts arefree of water and debris immediately prior to installationof the steel. The total number of strands in an individualtendon may be pulled into the duct as a unit, or theindividual strand may be pulled or pushed through the duct.

Anchorage devices or block-out templates for anchor-ages shall be set and held so that their axis coincides withthe axis of the tendon and anchor plates are normal in alldirections to the tendon.

The prestressing steel shall be distributed so that theforce in each girder stem is equal or as required by theplans, except as provided herein. For box girders withmore than two girder stems, at the Contractor’s option, theprestressing force may vary up to 5% from the theoreticalrequired force per girder stem provided the required totalforce in the superstructure is obtained and the force is dis-tributed symmetrically about the center line of the typicalsection.

10.4.2.2.1 Protection of Steel After Installation

Prestressing steel installed in members prior toplacing and curing of the concrete, or installed in the ductbut not grouted within the time limit specified below,shall be continuously protected against rust or other cor-rosion by means of a corrosion inhibitor placed in theducts or directly applied to the steel. The prestressingsteel shall be so protected until grouted or encased in con-crete. Prestressing steel installed and tensioned in mem-bers after placing and curing of the concrete and groutedwithin the time limit specified below will not require theuse of a corrosion inhibitor described herein and rustwhich may form during the interval between tendon in-stallation and grouting will not be cause for rejection ofthe steel.

The permissible interval between tendon installationand grouting without use of a corrosion inhibitor for var-ious exposure conditions shall be as follows:

Very Damp Atmosphere orover Saltwater 7 days(Humidity � 70%)

Moderate Atmosphere 15 days(Humidity from 40% to 70%)

Very Dry Atmosphere 20 days(Humidity � 40%)

After tendons are placed in ducts, the openings at the ends of the ducts shall be sealed to prevent entry ofmoisture.

When steam curing is used, steel for post-tensioningshall not be installed until the steam curing is completed.

Whenever electric welding is performed on or nearmembers containing prestressing steel, the weldingground shall be attached directly to the steel beingwelded. All prestressing steel and hardware shall be pro-tected from weld spatter or other damage.

10.4.3 Placement of Anchorage Hardware

The constructor is responsible for the proper placementof all materials according to the design documents of theengineer of record and the requirements stipulated by theanchorage device supplier. The Contractor shall exerciseall due care and attention in the placement of anchoragehardware, reinforcement, concrete, and consolidation ofconcrete in anchorage zones. Modifications to the localzone details verified under provisions of Article 9.21.7.3.in Division I and Article 10.3.2.3 in Division II shall beapproved by both the engineer of record and the anchor-age device supplier.

10.5 IDENTIFICATION AND TESTING

All wire, strand, or bars to be shipped to the site shallbe assigned a lot number and tagged for identification pur-poses. Anchorage assemblies to be shipped shall be like-wise identified.

Each lot of wire or bars and each reel of strand rein-forcement shall be accompanied by a manufacturer’s cer-tificate of compliance, a mill certificate, and a test report.The mill certificate and test report shall include the chem-ical composition (not required for strand), cross-sectionalarea, yield and ultimate strengths, elongation at rupture,modulus of elasticity, and the stress strain curve for the ac-tual prestressing steel intended for use. All values certifiedshall be based on test values and nominal sectional areasof the material being certified.

The Contractor shall furnish to the Engineer for verifi-cation testing the samples described in the following sub-articles selected from each lot. If ordered by the Engineer,



the selection of samples shall be made at the manufac-turer’s plant by the Inspector.

All samples submitted shall be representative of the lotto be furnished and, in the case of wire or strand, shall betaken from the same master roll.

The actual strength of the prestressing steel shall not beless than specified by the applicable ASTM Standard, andshall be determined by tests of representative samples ofthe tendon material in conformance with ASTM Stan-dards.

All of the materials specified for testing shall be fur-nished free of cost and shall be delivered in time for teststo be made well in advance of anticipated time of use.

10.5.1 Pretensioning Method Tendons

For pretensioned strands, one sample at least 7 feetlong shall be furnished in accordance with the require-ments of paragraph 9.1 of AASHTO M 203.

10.5.2 Post-Tensioning Method Tendons

The following lengths shall be furnished for each 20ton, or portion thereof, lot of material used in the work.

(a) For wires requiring heading—5 feet.(b) For wires not requiring heading—sufficient lengthto make up one parallel-lay cable 5 feet long consist-ing of the same number of wires as the cable to be fur-nished.(c) For strand to be furnished with fittings—5 feet be-tween near ends of fittings.(d) For bars to be furnished with threaded ends andnuts—5 feet between threads at ends.

10.5.3 Anchorage Assemblies and Couplers

The Contractor shall furnish for testing, one specimenof each size of prestressing tendon, including couplings,of the selected type, with end fittings and anchorage as-sembly attached, for strength tests only. These specimensshall be 5 feet in clear length, measured between ends offittings. If the results of the test indicate the necessity ofcheck tests, additional specimens shall be furnished with-out cost.

When dynamic testing is required, the Contractor shallperform the testing and shall furnish certified copies oftest results which indicate conformance with the specifiedrequirements prior to installation of anchorages or cou-plers.

For prestressing systems previously tested and ap-proved on projects having the same tendon configuration,the Engineer may not require complete tendon samples

provided there is no change in the material, design, or de-tails previously approved. Shop drawings or prestressingdetails shall identify the project on which approval wasobtained, otherwise testing shall be conducted.

10.6 PROTECTION OF PRESTRESSING STEEL

All prestressing steel shall be protected against physi-cal damage and rust or other results of corrosion at alltimes from manufacture to grouting. Prestressing steelshall also be free of deleterious material such as grease,oil, wax, or paint. Prestressing steel that has sustainedphysical damage at any time shall be rejected. The devel-opment of pitting or other results of corrosion, other thanrust stain, shall be cause for rejection.

Prestressing steel shall be packaged in containers orshipping forms for the protection of the strand againstphysical damage and corrosion during shipping and stor-age. A corrosion inhibitor which prevents rust or other re-sults of corrosion shall be placed in the package or form,or shall be incorporated in a corrosion inhibitor carriertype packaging material, or when permitted by the Engi-neer, may be applied directly to the steel. The corrosioninhibitor shall have no deleterious effect on the steel orconcrete or bond strength of steel to concrete or grout.Packaging or forms damaged from any cause shall be im-mediately replaced or restored to original condition.

The shipping package or form shall be clearly markedwith a statement that the package contains high-strengthprestressing steel, and the type of corrosion inhibitor used,including the date packaged.

All anchorages, end fittings, couplers, and exposedtendons, which will not be encased in concrete or grout inthe completed work, shall be permanently protectedagainst corrosion.

10.7 CORROSION INHIBITOR

Corrosion inhibitor shall consist of a vapor phase in-hibitor (VPI) powder conforming to the provisions ofFederal Specification MIL-P-3420 or as otherwise ap-proved by the Engineer. When approved, water soluble oilmay be used on tendons as a corrosion inhibitor.

10.8 DUCTS

Ducts used to provide holes or voids in the concrete for the placement of post-tensioned bonded tendons may be either formed with removable cores or may con-sist of rigid or semi-rigid ducts which are cast into theconcrete.



Ducts formed with removable cores shall be formedwith no constrictions which would tend to block thepassage of grout. All coring materials shall be removed.

Ducts formed by sheath left in place shall be a type that will not permit the intrusion of cement paste.They shall transfer bond stresses as required and shall retain shape under the weight of the concrete and shallhave sufficient strength to maintain their correctalignment without visible wobble during placement ofconcrete.

10.8.1 Metal Ducts

Sheathing for ducts shall be metal, except as providedherein. Such ducts shall be galvanized ferrous metal andshall be fabricated with either welded or interlockedseams. Galvanizing of welded seams will not be required.Rigid ducts shall have smooth inner walls and shall be ca-pable of being curved to the proper configuration withoutcrimping or flattening. Semi-rigid ducts shall becorrugated and when tendons are to be inserted after theconcrete has been placed their minimum wall thicknessshall be as follows: 26 gauge for ducts less than or equalto 25⁄ 8-inch diameter, 24 gauge for ducts greater than 25⁄ 8-inch diameter. When bar tendons are preassembledwith such ducts, the duct thickness shall not be less than31 gauge.

10.8.2 Polyethylene Duct

As an alternative to metal ducts, ducts for transversetendons in deck slabs and at other locations where shownor approved may be of high density polyethylene, con-forming to the material requirements of ASTM D 3350.

Polyethylene duct shall not be used when the radius ofcurvature of the tendon is less than 30 feet.

Semi-rigid polyethylene ducts for use where com-pletely embedded in concrete shall be corrugated with minimum material thickness of 0.050�0.010 inch.Such ducts shall have a white coating on the outside, orshall be of white material with ultraviolet stabilizersadded.

Rigid polyethylene ducts for use where the tendon is notembedded in concrete shall be rigid pipe manufactured inaccordance with ASTM D 2447, Grades P33 or P34; F714or D3350 with a cell classification of PE345433C. For external applications, such duct shall have an external diameter to wall thickness ratio of 21 or less.

For applications where polyethylene duct is exposed tosunlight or ultraviolet light, carbon black shall be incor-porated into the polyethylene pipe resin in such amount toprovide resistance to ultraviolet degradation in accor-dance with ASTM D 1248.

10.8.3 Duct Area

The inside diameter of ducts shall be at least 1⁄ 4 inchlarger than the nominal diameter of single wire, bar, orstrand tendons, or in the case of multiple wire, bar orstrand tendons, the inside cross-sectional area of thesheathing shall be at least two times the net area of the pre-stressing steel. When tendons are to be placed by the pullthrough method, the duct area shall be at least 21⁄ 2 timesthe net area of the prestressing steel.

10.8.4 Duct Fittings

Coupling and transition fittings for ducts formed bysheathing shall be of either ferrous metal or polyethylene,and shall be cement paste intrusion proof and of sufficientstrength to prevent distortion or displacement of the ductsduring concrete placement.

All ducts or anchorage assemblies shall be providedwith pipes or other suitable connections at each end of theduct for the injection of grout after prestressing. As spec-ified in Article 10.4.1.1, ducts shall also be provided withports for venting or grouting at high points and for drain-ing at intermediate low points.

Vent and drain pipes shall be 1⁄ 2-inch minimum diame-ter standard pipe or suitable plastic pipe. Connection toducts shall be made with metallic or plastic structural fas-teners. The vents and drains shall be mortar tight, taped asnecessary, and shall provide means for injection of groutthrough the vents and for sealing to prevent leakage ofgrout.

10.9 GROUT

Materials for use in making grout which is to be placedin the ducts after tendons are post-tensioned shall conformto the following.

10.9.1 Portland Cement

Portland cement shall conform to one of the following:Specifications for Portland Cement—AASHTO M 85(ASTM C 150), Types I, II, or III. Cement used for grout-ing shall be fresh and shall not contain any lumps or otherindication of hydration or “pack set.”

10.9.2 Water

The water used in the grout shall be potable, clean, andfree of injurious quantities of substances known to beharmful to Portland cement or prestressing steel.



10.9.3 Admixtures

Admixtures, if used, shall impart the properties of low-water content, good flowability, minimum bleed, and ex-pansion if desired. They shall contain no chemicals inquantities that may have harmful effect on the prestress-ing steel or cement. Admixtures which, at the dosageused, contain chlorides in excess of 0.005% of the weightof the cement used or contain any fluorides, sulphites, andnitrates shall not be used.

When a grout expanding admixture is required, or isused at the Contractor’s option, it shall be well dispersedthrough the other admixtures and shall produce a 2% to6% unrestrained expansion of the grout.

Amount of admixture to obtain a desired amount ofexpansion shall be determined by tests. If the source ofmanufacture or brand of either admixture or cementchanges after testing, new tests shall be conducted to de-termine proper proportions.

All admixtures shall be used in accordance with the in-structions of the manufacturer.

10.10 TENSIONING

10.10.1 General Tensioning Requirements

Prestressing steel shall be tensioned by hydraulic jacksso as to produce the forces shown on the plans or on theapproved working drawing with appropriate allowancesfor all losses. Losses to be provided for shall be as speci-fied in Division I, Article 9.16. For post-tensioned workthe losses shall also include the anchor set loss appropri-ate for the anchorage system employed.

For pretensioned members, the strand stress prior toseating (jacking stress) shall not exceed 80% of the mini-mum ultimate tensile strength of the prestressing steel(0.80 fs�). This allowable stress, which slightly exceeds thevalues allowed in Division I, Article 9.15.1, may be per-mitted to offset seating losses and to accommodate com-pensation for temperature differences specified in Article10.5.2.

For post-tensioned members, the strand stress prior toseating (jacking stress) and the stress in the steel immedi-ately after seating shall not exceed the values allowed inDivision I, Article 9.15.1.

The method of tensioning employed shall be one ofthe following as specified or approved:

(1) Pretensioning; in which the prestressing strand ortendons are stressed prior to being embedded in theconcrete placed for the member. After the concrete hasattained the required strength, the prestressing force is

released from the external anchorages and transferred,by bond, into the concrete.(2) Post-tensioning; in which the reinforcing tendonsare installed in voids or ducts within the concrete andare stressed and anchored against the concrete after thedevelopment of the required concrete strength. As afinal operation under this method, the voids or ductsare pressure-grouted.(3) Combined Method; in which part of the reinforce-ment is pretensioned and part post-tensioned. Underthis method all applicable requirements for preten-sioning and for post-tensioning shall apply to the re-spective reinforcing elements using these methods.

During stressing of strand, individual wire failuresmay be accepted by the Engineer, provided not more thanone wire in any strand is broken and the area of brokenwires does not exceed 2% of the total area of the pre-stressing steel in the member.

10.10.1.1 Concrete Strength

Prestressing forces shall not be applied or transferredto the concrete until the concrete has attained the strengthspecified for initial stressing. In addition, cast-in-placeconcrete for other than segmentally constructed bridgesshall not be post-tensioned until at least 10 days after thelast concrete has been placed in the member to be post-tensioned.

10.10.1.2 Prestressing Equipment

Hydraulic jacks used to stress tendons shall be capableof providing and sustaining the necessary forces and shallbe equipped with either a pressure gauge or a load cell fordetermining the jacking stress. The jacking system shallprovide an independent means by which the tendon elon-gation can be measured. The pressure gauge shall have anaccurately reading dial at least 6 inches in diameter or adigital display, and each jack and its gauge shall be cali-brated as a unit with the cylinder extension in the approx-imate position that it will be at final jacking force, and shallbe accompanied by a certified calibration chart or curve.The load cell shall be calibrated and shall be provided withan indicator by means of which the prestressing force inthe tendon may be determined. The range of the load cellshall be such that the lower 10% of the manufacturer’srated capacity will not be used in determining the jackingstress. When approved by the Engineer, calibrated provingrings may be used in lieu of load cells.

Recalibration of gauges shall be repeated at least an-nually and whenever gauge pressures and elongations in-dicate materially different stresses.



Only oxygen flame or mechanical cutting devices shallbe used to cut strand after installation in the member orafter stressing. Electric arc welders shall not be used.

10.10.1.3 Sequence of Stressing

When the sequence of stressing individual tendons isnot otherwise specified, the stressing of post-tensioningtendons and the release of pretensioned tendons shall bedone in a sequence that produces a minimum of eccentricforce in the member.

10.10.1.4 Measurement of Stress

A record of gauge pressures and tendon elongations foreach tendon shall be provided by the Contractor for re-view and approval by the Engineer. Elongations shall bemeasured to an accuracy of �1⁄ 16 inch. Stressing tails ofpost-tensioned tendons shall not be cut off until the stress-ing records have been approved.

The stress in tendons during tensioning shall be deter-mined by the gauge or load cell readings and shall be ver-ified with the measured elongations. Calculations of an-ticipated elongations shall utilize the modulus ofelasticity, based on nominal area, as furnished by the man-ufacturer for the lot of steel being tensioned, or as deter-mined by a bench test of strands used in the work.

All tendons shall be tensioned to a preliminary force as necessary to eliminate any take-up in the ten-sioning system before elongation readings are started.This preliminary force shall be between 5% and 25% of the final jacking force. The initial force shall be measuredby a dynamometer or by other approved method, so thatits amount can be used as a check against elongationas computed and as measured. Each strand shall be

marked prior to final stressing to permit measurement of elongation and to insure that all anchor wedges setproperly.

It is anticipated that there may be discrepancy in indi-cated stress between jack gauge pressure and elongation.In such event, the load used as indicated by the gaugepressure, shall produce a slight over-stress rather thanunder-stress. When a discrepancy between gauge pressureand elongation of more than 5% in tendons over 50 feetlong or 7% in tendons of 50 feet or less in length occurs,the entire operation shall be carefully checked and thesource of error determined and corrected before proceed-ing further. When provisional ducts are provided for ad-dition of prestressing force in event of an apparent forcedeficiency in tendons over 50 feet long, the discrepancybetween the force indicated by gauge pressure and elon-gation may be increased to 7% before investigation intothe source of the error.

10.10.2 Pretensioning Method Requirements

Stressing shall be accomplished by either single strandstressing or multiple strand stressing. The amount ofstress to be given each strand shall be as shown in theplans or the approved working drawings.

All strand to be stressed in a group (multiple strandstressing) shall be brought to a uniform initial tensionprior to being given their full pretensioning. The amountof the initial tensioning force shall be within the rangespecified in Article 10.5.1 and shall be the minimum re-quired to eliminate all slack and to equalize the stresses inthe tendons as determined by the Engineer. The amount ofthis force will be influenced by the length of the castingbed and the size and number of tendons in the group to betensioned.

Draped pretensioned tendons shall either be tensionedpartially by jacking at the end of the bed and partially byuplifting or depressing tendons, or they shall be tensionedentirely by jacking, with the tendons being held in theirdraped positions by means of rollers, pins, or other ap-proved methods during the jacking operation.

Approved low-friction devices shall be used at allpoints of change in slope of tendon trajectory when ten-sioning draped pretensioned strands, regardless of the ten-sioning method used.

If the load for a draped strand, as determined by elon-gation measurements, is more than 5% less than that indi-cated by the jack gauges, the strand shall be tensionedfrom both ends of the bed and the load as computed fromthe sum of elongation at both ends shall agree within 5%of that indicated by the jack gauges.

When ordered by the Engineer, prestressing steelstrands in pretensioned members, if tensioned individu-ally, shall be checked by the Contractor for loss of pre-stress not more than 3 hours prior to placing concrete forthe members. The method and equipment for checking theloss of prestress shall be subject to approval by the Engi-neer. All strands that show a loss of prestress in excess of3% shall be retensioned to the original computed jackingstress.

Stress on all strands shall be maintained between an-chorages until the concrete has reached the compressivestrength required at time of transfer of stress to concrete.

When prestressing steel in pretensioned members istensioned at a temperature more than 25°F lower than theestimated temperature of the concrete and the prestressingsteel at the time of initial set of the concrete, the calculatedelongation of the prestressing steel shall be increased tocompensate for the loss in stress, due to the change in tem-perature, but in no case shall the jacking stress exceed80% of the specified minimum ultimate tensile strength ofthe prestressing steel.



Strand splicing methods and devices shall be ap-proved by the Engineer. When single strand jacking isused, only one splice per strand will be permitted. Whenmulti-strand jacking is used, either all strands shall bespliced or no more than 10% of the strands shall bespliced. Spliced strands shall be similar in physical prop-erties, from the same source, and shall have the same“twist” or “lay.” All splices shall be located outside of theprestressed units.

Side and flange forms that restrain deflection shall beremoved before release of pretensioning reinforcement.

Except when otherwise shown on the plans, all preten-sioned-prestressing strands shall be cut off flush with theend of the member and the exposed ends of the strand anda 1-inch strip of adjoining concrete shall be cleaned andpainted. Cleaning shall be by wire brushing or abrasiveblast cleaning to remove all dirt and residue that is notfirmly bonded to the metal or concrete surfaces. The sur-faces shall be coated with one thick coat of zinc-rich paintconforming to the requirements of Federal SpecificationTT-P-641. The paint shall be thoroughly mixed at the timeof application, and shall be worked into any voids in thestrands.

10.10.3 Post-Tensioning Method Requirements

Prior to post-tensioning any member, the Contractorshall demonstrate to the satisfaction of the Engineer thatthe prestressing steel is free and unbonded in the duct.

All strands in each tendon, except for those in flat ductswith not more than four strands, shall be stressed simulta-neously with a multi-strand jack.

Tensioning shall be accomplished so as to provide theforces and elongations specified in Article 10.5.1.

Except as provided herein or when shown on the plans or on the approved working drawings, tendons in continuous post-tensioned members shall be ten-sioned by jacking at each end of the tendon. For straighttendons and when one end stressing is shown on theplans, tensioning may be performed by jacking from oneend or both ends of the tendon at the option of the Contractor.

10.11 GROUTING

10.11.1 General

When the post-tensioning method is used, the pre-stressing steel shall be provided with permanent protec-tion and shall be bonded to the concrete by completelyfilling the void space between the duct and the tendonwith grout.

10.11.2 Preparation of Ducts

All ducts shall be clean and free of deleterious materi-als that would impair bonding or interfere with groutingprocedures.

Ducts with concrete walls (cored ducts) shall beflushed to ensure that the concrete is thoroughly wetted.Metal ducts shall be flushed if necessary to remove dele-terious material.

Water used for flushing ducts may contain slack lime(calcium hydroxide) or quicklime (calcium oxide) in theamount of 0.1 lb per gallon.

After flushing, all water shall be blown out of the ductwith oil-free compressed air.

10.11.3 Equipment

The grouting equipment shall include a mixer capableof continuous mechanical mixing which will produce agrout free of lumps and undispersed cement, a grout pumpand standby flushing equipment with water supply. Theequipment shall be able to pump the mixed grout in amanner which will comply with all requirements.

Accessory equipment which will provide for accuratesolid and liquid measures shall be provided to batch allmaterials.

The pump shall be a positive displacement type and beable to produce an outlet pressure of at least 150 psi. Thepump should have seals adequate to prevent introductionof oil, air, or other foreign substance into the grout, and toprevent loss of grout or water.

A pressure gauge having a full-scale reading of nogreater than 300 psi shall be placed at some point in thegrout line between the pump outlet and the duct inlet.

The grouting equipment shall contain a screen havingclear openings of 0.125-inch maximum size to screen thegrout prior to its introduction into the grout pump. If agrout with a thixotropic additive is used, a screen openingof 3⁄ 16 inch is satisfactory. This screen shall be easily ac-cessible for inspection and cleaning.

The grouting equipment shall utilize gravity feed to thepump inlet from a hopper attached to and directly over it.The hopper must be kept at least partially full of grout atall times during the pumping operation to prevent air frombeing drawn into the post-tensioning duct.

Under normal conditions, the grouting equipment shallbe capable of continuously grouting the largest tendon onthe project in no more than 20 minutes.

10.11.4 Mixing of Grout

Water shall be added to the mixer first, followed byPortland cement and admixture, or as required by the ad-mixture manufacturer.



Mixing shall be of such duration as to obtain a uniform,thoroughly blended grout, without excessive temperatureincrease or loss of expansive properties of the admixture.The grout shall be continuously agitated until it is pumped.

Water shall not be added to increase grout flowabilitywhich has been decreased by delayed use of the grout.

Proportions of materials shall be based on tests madeon the grout before grouting is begun, or may be selectedbased on prior documented experience with similar mate-rials and equipment and under comparable field condi-tions (weather, temperature, etc.). The water content shallbe the minimum necessary for proper placement, andwhen Type I or II cement is used shall not exceed a water-cement ratio of 0.45 or approximately 5 gallons of waterper sack (94 lb) of cement.

The water content required for Type III cement shall beestablished for a particular brand based on tests.

The pumpability of the grout may be determined by theEngineer in accordance with the U.S. Corps of EngineersMethod CRD-C79. When this method is used, the effluxtime of the grout sample immediately after mixing shallnot be less than 11 seconds. The flow cone test does notapply to grout which incorporates a thixotropic additive.

10.11.5 Injection of Grout

All grout and high-point vent openings shall be openwhen grouting starts. Grout shall be allowed to flow fromthe first vent after the inlet pipe until any residual flushingwater or entrapped air has been removed, at which timethe vent should be capped or otherwise closed. Remain-ing vents shall be closed in sequence in the same manner.

The pumping pressure at the tendon inlet shall not ex-ceed 250 psi.

If the actual grouting pressure exceeds the maximumrecommended pumping pressure, grout may be injected atany vent which has been, or is ready to be capped as longas a one-way flow of grout is maintained. If this procedureis used, the vent which is to be used for injection shall befitted with a positive shutoff.

When one-way flow of grout cannot be maintained, thegrout shall be immediately flushed out of the duct withwater.

Grout shall be pumped through the duct and continu-ously wasted at the outlet pipe until no visible slugs ofwater or air are ejected and the efflux time of the ejectedgrout, as measured by a flow cone test, if used, is not lessthan that of the injected grout. To ensure that the tendonremains filled with grout, the outlet shall then be closed

and the pumping pressure allowed to build to a minimumof 75 psi before the inlet vent is closed. Plugs, caps, orvalves thus required shall not be removed or opened untilthe grout has set.

10.11.6 Temperature Considerations

When temperatures are below 32°F, ducts shall be keptfree of water to avoid damage due to freezing.

The temperature of the concrete shall be 35°F or higherfrom the time of grouting until job cured 2-inch cubes ofgrout reach a minimum compressive strength of 800 psi.

Grout shall not be above 90°F during mixing or pump-ing. If necessary, the mixing water shall be cooled.


10.12.1 Measurement

The prestressing of cast-in-place concrete will be mea-sured by the lump sum for each item or location listed inthe schedule of bid items.

10.12.2 Payment

No separate payment will be made for prestressing pre-cast concrete members. Payment for prestressing precastconcrete members shall be considered as included in thecontract price paid for the precast members as providedfor in Section 8, “Concrete Structures.”

The contract lump sum price paid for prestressing cast-in-place concrete shall include full compensation for fur-nishing all labor, materials, tools, equipment and inciden-tals, and for doing all work involved in furnishing,placing, and tensioning the prestressing steel in cast-in-place concrete structures, complete in place, as shown onthe plans, as specified in these Specifications and the spe-cial provisions, and as directed by the Engineer.

Full compensation for furnishing and placing addi-tional concrete and deformed bar reinforcing steel re-quired by the particular system used, ducts, anchoring de-vices, distribution plates or assemblies and incidentalparts, for furnishing samples for testing, working draw-ings, and for pressure grouting ducts shall be consideredas included in the contract lump sum price paid for pre-stressing cast-in-place concrete or in the contract price forfurnishing precast members, and no additional compensa-tion will be allowed therefore.



Section 11STEEL STRUCTURES

11.1 GENERAL

11.1.1 Description

This work shall consist of furnishing, fabricating, anderecting steel structures and structural steel portions ofother structures in accordance with these Specifications,the Special Provisions and the details shown on the plans.

The structural steel fabricating plant shall be certifiedunder the AISC Quality Certification Program, CategoryI. The fabrication of fracture critical members shall beCategory III.

Details of design which are permitted to be selectedby the Contractor shall conform to Division I of theseSpecifications.

Painting shall conform to the provisions of Section 13,“Painting,” of these Specifications.

Falsework used in the erection of structural steel shallconform to the provisions of Section 3, “TemporaryWorks,” of these Specifications.

Structural components designated on the plans or inthe special provisions as “fracture critical” shall conformto the provisions of Chapter 12 of the ANSI/AASHTO/AWS D1.5 Bridge Welding Code.

Welding and weld qualification tests shall conform tothe provisions of the current ANSI/AASHTO/AWS D1.5Bridge Welding Code.

11.1.2 Notice of Beginning of Work

The Contractor shall give the Engineer ample notice ofthe beginning of work at the mill or in the shop, so that in-spection may be provided. The term “mill” means anyrolling mill or foundry where material for the work is tobe manufactured. No material shall be manufactured, orwork done in the shop, before the Engineer has been sonotified.

11.1.3 Inspection

Structural steel will be inspected at the fabrication site.The Contractor shall furnish to the Engineer a copy of all

mill orders and certified mill test reports. Mill test reportsshall show the chemical analysis and physical test resultsfor each heat of steel used in the work.

With the approval of the Engineer, certificates of com-pliance shall be furnished in lieu of mill test reports formaterial that normally is not supplied with mill test re-ports, and for items such as fills, minor gusset plates andsimilar material when quantities are small and the mater-ial is taken from stock.

Certified mill test reports for steels with specifiedimpact values shall include, in addition to other test re-sults, the results of Charpy V-notch impact tests. Whenfine grain practice is specified, the test report shallconfirm that the material was so produced. Copies of millorders shall be furnished at the time orders are placedwith the manufacturer. Certified mill test reports andCertificates of Compliance shall be furnished prior to thestart of fabrication of material covered by these reports.The Certificate of Compliance shall be signed by themanufacturer and shall certify that the material is inconformance with the specifications to which it has beenmanufactured.

Material to be used shall be made available to theEngineer so that each piece can be examined. The Engi-neer shall have free access at all times to any portion ofthe fabrication site where the material is stored or wherework on the material is being performed.

11.1.4 Inspector’s Authority

The Inspector shall have the authority to reject materi-als or workmanship which do not fulfill the requirementsof these Specifications. In cases of dispute, the Contractormay appeal to the Engineer, whose decision shall be final.

Inspection at the mill and shop is intended as a meansof facilitating the work and avoiding errors, and it is ex-pressly understood that it will not relieve the Contractorof any responsibility in regard to defective material orworkmanship and the necessity for replacing the same.

The acceptance of any material or finished members bythe Inspector shall not be a bar to their subsequent rejec-tion, if found defective. Rejected materials and workman-

565


ship shall be replaced as soon as practical or corrected bythe Contractor.


The Contractor shall expressly understand that the En-gineer’s approval of the working drawings submitted bythe Contractor covers the requirements for “strength anddetail,” and that the Engineer assumes no responsibilityfor errors in dimensions.


11.2.1 Shop Drawings

The Contractor shall submit copies of the detailed shopdrawings to the Engineer for approval. Working drawingsshall be submitted sufficiently in advance of the start of theaffected work to allow time for review by the Engineer andcorrections by the Contractor without delaying the work.

Working drawings for steel structures shall give fulldetailed dimensions and sizes of component parts of thestructure and details of all miscellaneous parts, such aspins, nuts, bolts, drains, etc.

Where specific orientation of plates is required, the di-rection of rolling of plates shall be shown.

Working drawings shall specifically identify eachpiece that is to be made of steel which is to be other thanAASHTO M 270 (ASTM A 709) Grade 36 steel.

11.2.2 Erection Drawings

The Contractor shall submit drawings illustrating fullyhis or her proposed method of erection. The drawingsshall show details of all falsework bents, bracing, guys,dead-men, lifting devices, and attachments to the bridgemembers: sequence of erection, location of cranes andbarges, crane capacities, location of lifting points on thebridge members, and weights of the members. The planand drawings shall be complete in detail for all anticipatedphases and conditions during erection. Calculations maybe required to demonstrate that allowable stresses are notexceeded and that member capacities and final geometrywill be correct.

11.2.3 Camber Diagram

A camber diagram shall be furnished to the Engineerby the Fabricator, showing the camber at each panel point

in the cases of trusses or arch ribs, and at the location offield splices and fractions of span length (1 ⁄4 points mini-mum) in the cases of continuous beam and girders or rigidframes. The camber diagram shall show calculated cam-bers to be used in preassembly of the structure in accor-dance with Article 11.5.3.

11.3 MATERIALS

11.3.1 Structural Steel

11.3.1.1 General

Steel shall be furnished according to the followingspecifications. The grade or grades of steel to be furnishedshall be as shown on the plans or specified.

All steel for use in main load-carrying member com-ponents subject to tensile stresses shall conform to the ap-plicable Charpy V-notch Impact Test requirements ofAASHTO M 270 (ASTM A 709).

Welded girders made of ASTM A 709, Grade HPS70W steels shall be fabricated in accordance with theAASHTO Guide Specifications for Highway Bridge Fab-rication with HPS70W Steel, which supplements theANSI/AASHTO/ AWS D1.5 Bridge Welding Code.

11.3.1.2 Carbon Steel

Unless otherwise specified, structural carbon steel for bolted or welded construction shall conform to: Struc-tural Steel for Bridges, AASHTO M 270 (ASTM A 709)Grade 36.

11.3.1.3 High-Strength Low-Alloy StructuralSteel

High-strength low-alloy steel shall conform to:

Structural Steel for Bridges, AASHTO M 270 (ASTMA 709) Grades 50 or 50W.

11.3.1.4 High-Strength Low-Alloy, Quenchedand Tempered Structural Steel Plate

High-strength, low-alloy quenched and tempered steelplate shall conform to AASHTO M 270 (ASTM A 709)Grade 70W, or Grade HPS70W.

11.3.1.5 High-Yield Strength, Quenched andTempered Alloy Steel Plate

High-yield strength, quenched, and tempered alloysteel plate shall conform to:



(a) Structural Steel for Bridges, AASHTO M 270(ASTM A 709) Grades 100 or 100W.(b) Quenched and tempered alloy steel structural shapesand seamless mechanical tubing, meeting all of the me-chanical and chemical requirements of AASHTO M 270(ASTM A 709) Grades 100 or 100W steel, except thatthe specified maximum tensile strength may be 140,000psi for structural shapes and 145,000 psi for seamlessmechanical tubing, shall be considered as AASHTO M 270 (ASTM A 709) Grades 100 and 100W steel.

11.3.1.6 Eyebars

Steel for eyebars shall be of a weldable grade. Thesegrades include structural steel conforming to:

(a) Structural Steel for Bridges, AASHTO M 270(ASTM A 709) Grade 36.(b) Structural Steel for Bridges, AASHTO M 270(ASTM A 709) Grades 50 and 50W.

11.3.1.7 Structural Tubing

Structural tubing shall be either cold-formed welded orseamless tubing conforming to ASTM 500, Grade B orhot-formed welded or seamless tubing conforming toASTM 501.

11.3.2 High-Strength Fasteners

11.3.2.1 Material

High-strength bolts for structural steel joints shall con-form to either AASHTO M 164 (ASTM A 325) orAASHTO M 253 (ASTM A 490). When high-strengthbolts are used with unpainted weathering grades of steel,the bolts shall be Type 3.

The supplier shall provide a lot number appearing onthe shipping package and a certification noting when andwhere all testing was done, including rotational capacitytests, and zinc thickness when galvanized bolts and nutsare used.

The maximum hardness for AASHTO M 164 (ASTMA 325) bolts 1 inch or less in diameter shall be 33 HRC.

Proof load tests (ASTM F 606 Method 1) are requiredfor the bolts. Wedge tests of full-sized bolts are requiredin accordance with Section 8.3 of AASHTO M 164. Gal-vanized bolts shall be wedge tested after galvanizing.Proof load tests (AASHTO M 291) are required for thenuts. The proof load tests for nuts to be used with galva-nized bolts shall be performed after galvanizing, overtap-ping, and lubricating.

Except as noted below, nuts for AASHTO M 164(ASTM A 325) bolts shall conform to AASHTO M 291

(ASTM A 563) Grades DH, DH3, C, C3, and D. Nuts forAASHTO M 253 (ASTM A 490) bolts shall conform to therequirements of AASHTO M 291 (ASTM A 563) GradesDH and DH3.

• Nuts to be galvanized (hot-dip or mechanically gal-vanized) shall be heat treated Grade DH or DH3.

• Plain (ungalvanized) nuts shall have a minimumhardness of 89 HRB.

• Nuts to be used with AASHTO M 164 (ASTM A325) Type 3 bolts shall be of Grade C3 or DH3. Nutsto be used with AASHTO M 253 (ASTM A 490)bolts shall be of Grade DH3.

All galvanized nuts shall be lubricated with a lubricantcontaining a visible dye. Black bolts must be oily to touchwhen delivered and installed.

Washers shall be hardened steel washers conforming tothe requirements of AASHTO M 293 (ASTM F 436) andArticle 11.5.6.4.3.

11.3.2.2 Identifying Marks

AASHTO M 164 (ASTM A 325) for bolts and thespecifications referenced therein for nuts require that boltsand nuts manufactured to the specification be identified byspecific markings on the top of the bolt head and on oneface of the nut. Head markings must identify the grade bythe symbol “A 325,” the manufacturer and the type, if Type 2 or 3. Nut markings must identify the grade, themanufacturer and if Type 3, the type. Markings on directtension indicators must identify the manufacturer andType “325.” Other washer markings must identify themanufacturer and if Type 3, the type.

AASHTO M 253 (ASTM A 490) for bolts and thespecifications referenced therein for nuts require that boltsand nuts manufactured to the specifications be identifiedby specific markings on the top of the bolt head and on oneface of the nut. Head markings must identify the grade bythe symbol “A 490,” the manufacturer and the type, ifType 2 or 3. Nut markings must identify the grade, themanufacturer and if Type 3, the type. Markings on directtension indicators must identify the manufacturer andType “490.” Other washer markings must identify themanufacturer and if Type 3, the type.

11.3.2.3 Dimensions

Bolt and nut dimensions shall conform to the require-ments for Heavy Hexagon Structural Bolts and for HeavySemi-Finished Hexagon Nuts given in ANSI StandardB18.2.1 and B18.2.2, respectively.



11.3.2.4 Galvanized High-Strength Fasteners

When fasteners are galvanized, they shall be specifiedto be hot-dip galvanized in accordance with AASHTO M232 (ASTM A 153) Class C or, mechanically galvanizedin accordance with AASHTO M 298 (ASTM B 695) Class50. Bolts to be galvanized shall be either AASHTO M 164(ASTM A 325) Type 1 or Type 2 except that Type 2 boltsshall only be mechanically galvanized. Galvanized boltsshall be tension tested after galvanizing. Washers, nutsand bolts of any assembly shall be galvanized by the sameprocess. The nuts should be overtapped to the minimumamount required for the fastener assembly, and shall be lu-bricated with a lubricant containing a visible dye so a vis-ual check can be made for the lubricant at the time of fieldinstallation. AASHTO M 253 (ASTM A 490) bolts shallnot be galvanized.

11.3.2.5 Alternative Fasteners

Other fasteners or fastener assemblies, such as thoseconforming to the requirements of ASTM F 1852, whichmeet the materials, manufacturing, and chemical compo-sition requirements of AASHTO M 164 (ASTM A 325) orAASHTO M 253 (ASTM A 490), and which meet the me-chanical property requirements of the same specificationin full-sized tests, and which have body diameter andbearing areas under the head and nut, or their equivalent,not less than those provided by a bolt and nut of the samenominal dimensions prescribed in Article 11.3.2.3, maybe used, subject to the approval of the Engineer. Such al-ternate fasteners may differ in other dimensions fromthose of the specified bolts and nuts.

Subject to the approval of the Engineer, high-strengthsteel lock-pin and collar fasteners may be used as analternate for high-strength bolts as shown on the plans.The shank and head of high-strength steel lock-pin andcollar fasteners shall meet the requirements of Article11.3.2.3. Each fastener shall provide a solid shank body ofsufficient diameter to provide tensile and shear strengthequivalent to or greater than that of the bolt specified,shall have a cold forged head on one end, of type and di-mensions as approved by the Engineer, a shank lengthsuitable for material thickness fastened, locking grooves,breakneck groove and pull grooves (all annular grooves)on the opposite end. Each fastener shall provide a steellocking collar of proper size for shank diameter usedwhich, by means of suitable installation tools, is coldswaged into the locking grooves forming head for thegrooved end of the fastener after the pull groove sectionhas been removed. The steel locking collar shall be a stan-dard product of an established manufacturer of lockpinand collar fasteners, as approved by the Engineer.

11.3.2.6 Load Indicator Devices

Load indicating devices may be used in conjunctionwith bolts, nuts, and washers specified in Article 11.3.2.1.Load indicating devices shall conform to the requirementsof ASTM Specification for Compressible-Washer TypeDirect Tension Indicators For Use with Structural Fasten-ers, ASTM F 959, except as provided in the followingparagraph.

Subject to the approval of the Engineer, alternate designdirect tension indicating devices may be used providedthey satisfy the requirements of Article 11.5.6.4.6 or otherrequirements detailed in specifications provided by themanufacturer and subject to the approval of the Engineer.

11.3.3 Welded Stud Shear Connectors

11.3.3.1 Materials

Shear connector studs shall conform to the require-ments of Cold Finished-Carbon Steel Bars and Shafting.AASHTO M 169 (ASTM A 108), cold drawn bars, grades1015, 1018, or 1020, either semi- or fully killed. If flux re-taining caps are used, the steel for the caps shall be of alow carbon grade suitable for welding and shall complywith Cold-Rolled Carbon Steel Strip, ASTM A 109.

Tensile properties as determined by tests of bar stockafter drawing or of finished studs shall conform to the fol-lowing requirements:

Tensile strength 60,000 psi (min.)Yield strength* 50,000 psi (min.)Elongation 20% in 2 inches (min.)Reduction of area 50% (min.)

*As determined by a 0.2% offset method.

11.3.3.2 Test Methods

Tensile properties shall be determined in accordancewith the applicable sections of ASTM A370, MechanicalTesting of Steel Products. Tensile tests of finished studsshall be made on studs welded to test plates using a testfixture similar to that shown in Figure 7.2 of the currentANSI/AASHTO/AWS D1.5 Bridge Welding Code. If frac-ture occurs outside of the middle half of the gage length,the test shall be repeated.

11.3.3.3 Finish

Finished studs shall be of uniform quality and condi-tion, free from injurious laps, fins, seams, cracks, twists,bends, or other injurious defects. Finish shall be as pro-duced by cold drawing, cold rolling, or machining.



11.3.3.4 Certification

The manufacturer shall certify that the studs as deliv-ered are in accordance with the material requirements ofthis section. Certified copies of in-plant quality controltest reports shall be furnished to the Engineer uponrequest.

11.3.3.5 Check Samples

The Engineer may select, at the Contractor’s ex-pense, studs of each type and size used under the con-tract, as necessary for checking the requirements of thissection.

11.3.4 Steel Forgings and Steel Shafting

11.3.4.1 Steel Forgings

Steel forgings shall conform to the Specifications for Steel Forgings Carbon and Alloy for General Use, AASHTO M 102 (ASTM A 668), Classes C, D, F, or G.

11.3.4.2 Cold Finished Carbon Steel Shafting

Cold finished carbon steel shafting shall conform to thespecifications for Cold Finished Carbon Steel Bars Stan-dard Quality, AASHTO M 169 (ASTM A 108). Grade10160-10300, inclusive, shall be furnished unless other-wise specified.

11.3.5 Steel Castings

11.3.5.1 Mild Steel Castings

Steel castings for use in highway bridge componentsshall conform to Standard Specifications for Steel Cast-ings for Highway Bridges, AASHTO M 192 (ASTM A 486) or Carbon-Steel Castings for General Applica-tions, AASHTO M 103 (ASTM A 27). The Class 70 orGrade 70-36 of steel, respectively, shall be used unlessotherwise specified.

11.3.5.2 Chromium Alloy-Steel Castings

Chromium alloy-steel castings shall conform to theSpecification for Corrosion-Resistant Iron-Chromium,Iron-Chromium-Nickel and Nickel-Based Alloy Castingsfor General Application, AASHTO M 163 (ASTM A 743). Grade CA 15 shall be furnished unless otherwisespecified.

11.3.6 Iron Castings

11.3.6.1 Materials

(1) Gray Iron Castings—Gray iron castings shall con-form to the Specification for Gray Iron Castings,AASHTO M 105 (ASTM A 48), Class No. 30 unlessotherwise specified.(2) Ductile Iron Castings—Ductile iron castings shall conform to the Specifications for Ductile IronCastings, ASTM A 536, Grade 60-40-18 unlessotherwise specified. In addition to the specified testcoupons, test specimens from parts integral with thecastings, such as risers, shall be tested for castingsweighing more than 1,000 pounds to determine thatthe required quality is obtained in the castings in thefinished condition.(3) Malleable Castings—Malleable castings shallconform to the Specification for Malleable Iron Cast-ings, ASTM A 47. Grade No. 35018 shall be furnishedunless otherwise specified.

11.3.6.2 Workmanship and Finish

Iron castings shall be true to pattern in form and di-mensions, free from pouring faults, sponginess, cracks,blow holes, and other defects in positions affecting theirstrength and value for the service intended.

Castings shall be boldly filleted at angles and the ar-rises shall be sharp and perfect.

11.3.6.3 Cleaning

All castings must be sandblasted or otherwise effec-tively cleaned of scale and sand so as to present a smooth,clean, and uniform surface.

11.3.7 Galvanizing

When galvanizing is shown on the plans or spec-ified in the special provisions, ferrous metal products,other than fasteners and hardware items, shall be gal-vanized in accordance with the Specifications for Zinc (Hot-Galvanized) Coatings on Products Fabricatedfrom Rolled, Pressed, and Forged Steel Shape Plates,Bars, and Strip, AASHTO M 111 (ASTM A 123). Fas-teners and hardware items shall be galvanized in accor-dance with the Specification for Zinc Coating (Hot-Dip)on Iron and Steel Hardware, AASHTO M 232 (ASTM A153) except as noted in Article 11.3.2.4 for high-strengthfasteners.



11.4 FABRICATION

11.4.1 Identification of Steels During Fabrication

The Contractor’s system of assembly-marking indi-vidual pieces, and the issuance of cutting instructions tothe shop (generally by cross-referencing of the assembly-marks shown on the shop drawings with the correspond-ing item covered on the mill purchase order) shall be suchas to maintain identity of the original piece. The Contrac-tor may furnish from stock, material that can be identifiedby heat number and mill test report.

During fabrication, up to the point of assemblingmembers, each piece of steel, other than Grade 36 steel, shall show clearly and legibly its specification.

Any piece of steel, other than Grade 36 steel, whichprior to assembling into members, will be subject to fab-ricating operations such as blast cleaning, galvanizing,heating for forming, or painting which might obliteratemarking, shall be marked for grade by steel die stampingor by a substantial tag firmly attached. Steel die stampsshall be low stress-type.

Upon request, by the Engineer, the Contractor shallfurnish an affidavit certifying that throughout the fabrica-tion operation the identification of steel has been main-tained in accordance with this specification.

11.4.2 Storage of Materials

Structural material, either plain or fabricated, shall bestored above the ground on platforms, skids, or other sup-ports. It shall be kept free from dirt, grease, and other for-eign matter, and shall be protected as far as practicablefrom corrosion. See Article 11.5.6.4 for storage of high-strength fasteners.

11.4.3 Plates

11.4.3.1 Direction of Rolling

Unless otherwise shown on the plans, steel plates formain members and splice plates for flanges and main ten-sion members, not secondary members, shall be cut andfabricated so that the primary direction of rolling is paral-lel to the direction of the main tensile and/or compressivestresses.

11.4.3.2 Plate Cut Edges

11.4.3.2.1 Edge Planing

Sheared edges of plate more than 5 ⁄8 inch in thicknessand carrying calculated stress shall be planed, milled,ground, or thermal cut to a depth of 1 ⁄4 inch.

11.4.3.2.2 Oxygen Cutting

Oxygen cutting of structural steel shall conform to therequirements of the current ANSI/AASHTO/AWS D1.5Bridge Welding Code.

11.4.3.2.3 Visual Inspection and Repair of PlateCut Edges

Visual inspection and repair of plate cut edges shall be in accordance with the current ANSI/AASHTO/AWSD1.5 Bridge Welding Code.

11.4.3.3 Bent Plates

11.4.3.3.1 General

Cold bending of fracture critical steels and fracturecritical members is prohibited. Perform cold bending ofother steels or members in accordance with the ANSI/AASHTO/AWS D1.5 Bridge Welding Code and Table11.4.3.3.2, and in a manner such that no cracking occurs.

11.4.3.3.2 Cold Bending

For bent plates, the bend radius and the radius of themale die should be as liberal as the finished part will per-mit. The width across the shoulders of the female dieshould be at least 8 times the plate thickness for Grade 36steel. Higher strength steels require larger die openings.The surface of the dies in the area of radius should besmooth.

Where the concave face of a bent plate must fit tightlyagainst another surface, the male die should be sufficientlythick and have the proper radius to ensure that the bentplate has the required concave surface.

Since cracks in cold bending commonly originate fromthe outside edges, shear burrs and gas cut edges should beremoved by grinding. Sharp corners on edges and onpunched or gas cut holes should be removed by chamfer-ing or grinding to a radius.

Unless otherwise approved, the minimum bend radiifor cold forming (at room temperature), measured to theconcave face of the plate, are given in Table 11.4.3.3.2. Ifa smaller radius is required, heat may be needed to be apart of the bending procedure. Provide the heating proce-dure for review by the Engineer. For grades not includedin Table 11.4.3.3.2, follow minimum bend radii recom-mendations of the plate producer.

If possible, orient bend lines perpendicular to the di-rection of final rolling of the plate. If the bend line is par-allel to the direction of final rolling, multiply the sug-gested minimum radii in Table 11.4.3.3.2 by 1.5.



11.4.3.3.3 Hot Bending

If a radius shorter than the minimum specified for coldbending is essential, the plates shall be bent hot at a tem-perature not greater than 1,200°F, except for Grades 70W,100 and 100W. If Grades 100 and 100W steel plates to bebent are heated to a temperature greater than 1,100°F, orGrade 70W plates to be bent are heated to a temperaturegreater than 1,050°F, they must be requenched and tem-pered in accordance with the producing mill’s practiceand tested to verify restoration of specified properties, asdirected by the Engineer. Grade HPS70W steel to be bentshall not be heated to a temperature greater than 1,100°F.Requenching and tempering is not required for GradeHPS70W steel heated to this limit.

11.4.4 Fit of Stiffeners

End bearing stiffeners for girders and stiffeners in-tended as supports for concentrated loads shall have fullbearing (either milled, ground or, on weldable steel incompression areas of flanges, welded as shown on theplans or specified) on the flanges to which they transmitload or from which they receive load. Intermediate stiff-eners not intended to support concentrated loads, unlessshown or specified otherwise, shall have a tight fit againstthe compression flange.

11.4.5 Abutting Joints

Abutting joints in compression members of trusses andcolumns shall be milled or saw-cut to give a square jointand uniform bearing. At other joints, not required to befaced, the opening shall not exceed 3 ⁄8 inch.

11.4.6 Facing of Bearing Surfaces

The surface finish of bearing and base plates and otherbearing surfaces that are to come in contact with eachother or with concrete shall meet the ANSI surface rough-

ness requirements as defined in ANSI B46.1, SurfaceRoughness, Waviness and Lay, Part I:

Steel slabs . . . . . . . . . . . . . . . . . . . . . . ANSI 2,000Heavy plates in contact in shoes tobe welded . . . . . . . . . . . . . . . . . . . . . ANSI 1,000

Milled ends of compression members,milled or ground ends of stiffenersand fillers . . . . . . . . . . . . . . . . . . . . . ANSI 500

Bridge rollers and rockers. . . . . . . . . . ANSI 250Pins and pin holes . . . . . . . . . . . . . . . . ANSI 125Sliding bearings . . . . . . . . . . . . . . . . . ANSI 125

11.4.7 Straightening Material

The straightening of plates, angles, other shapes, andbuilt-up members, when permitted by the Engineer, shall bedone by methods that will not produce fracture or other in-jury to the metal. Distorted members shall be straightenedby mechanical means or, if approved by the Engineer, bycarefully planned procedures and supervised application ofa limited amount of localized heat, except that heat straight-ening of AASHTO M 270 (ASTM A 709) Grades 70W,HPS70W, 100 and 100W steel members shall be done onlyunder rigidly controlled procedures, each application sub-ject to the approval of the Engineer. In no case shall themaximum temperature exceed values in the following table.

Grade 70W 1,050°FGrade HPS70W 1,100°FGrade 100 or 100W 1,100°F

In all other steels, the temperature of the heated area shallnot exceed 1,200°F as controlled by temperature indicatingcrayons, liquids, or bimetal thermometers. Heating in ex-cess of the limits shown shall be cause for rejection, unlessthe Engineer allows testing to verify material integrity.

Parts to be heat straightened shall be substantially freeof stress and from external forces, except stresses result-ing from mechanical means used in conjunction with theapplication of heat.

Evidence of fracture following straightening of a bendor buckle will be cause for rejection of the damaged piece.

11.4.8 Bolt Holes

11.4.8.1 Holes for High-Strength Bolts andUnfinished Bolts*

11.4.8.1.1 General

All holes for bolts shall be either punched or drilled ex-cept as noted herein. Material forming parts of a member


*See Article 11.5.5 for bolts included in designation “UnfinishedBolts.”

Thickness Up to Over 3/4 Over 1 Inches (t) 3/4 to 1, incl. to 2, incl. Over 2

ASTM A 709/ AASHTO M 270

Grades36 1.5t 1.5t 1.5t 2.0t50 1.5t 1.5t 2.0t 2.5t50W 1.5t 1.5t 2.0t 2.5tHPS70W 1.5t 1.5t 2.5t 3.0t100 1.75t 2.25t 4.5t 5.5t100W 1.75t 2.25t 4.5t 5.5t

TABLE 11.4.3.3.2 Minimum Cold-Bending Radii


composed of not more than five thicknesses of metal maybe punched 1 ⁄16 inch larger than the nominal diameter ofthe bolts whenever the thickness of the material is notgreater than 3 ⁄4 inch for structural steel, 5 ⁄8 inch for high-strength steel or 1 ⁄2 inch for quenched and tempered alloysteel, unless subpunching and reaming are required underArticle 11.4.8.5.

When material is thicker than 3 ⁄4 inch for structuralsteel, 5 ⁄8 inch for high-strength steel, or 1 ⁄2 inch forquenched and tempered alloy steel, all holes shall eitherbe subdrilled and reamed or drilled full size. Also, whenmore than five thicknesses are joined, or as required byArticle 11.4.8.5, material shall be subdrilled and reamedor drilled full size while in assembly.

When required, all holes shall be either subpunched orsubdrilled (subdrilled if thickness limitation governs) 3 ⁄16

inch smaller and, after assembling, reamed 1 ⁄16 inch largeror drilled full size to 1 ⁄16 inch larger than the nominaldiameter of the bolts.

When shown on the plans, enlarged or slotted holes areallowed with high-strength bolts.

11.4.8.1.2 Punched Holes

The diameter of the die shall not exceed the diameterof the punch by more than 1 ⁄16 inch. If any holes must beenlarged to admit the bolts, such holes shall be reamed.Holes must be clean cut without torn or ragged edges. Theslightly conical hole that naturally results from punchingoperations is considered acceptable.

11.4.8.1.3 Reamed or Drilled Holes

Reamed or drilled holes shall be cylindrical, perpen-dicular to the member, and shall comply with the require-ments of Article 11.4.8.1.1 as to size. Where practical,reamers shall be directed by mechanical means. Burrs onthe outside surfaces shall be removed. Reaming anddrilling shall be done with twist drills, twist reamers or ro-tobroach cutters. Connecting parts requiring reamed ordrilled holes shall be assembled and securely held whilebeing reamed or drilled and shall be match marked beforedisassembling.

11.4.8.1.4 Accuracy of Holes

Holes not more than 1 ⁄32 inch larger in diameter thanthe true decimal equivalent of the nominal diameter thatmay result from a drill or reamer of the nominal diameterare considered acceptable. The width of slotted holeswhich are produced by flame cutting or a combination ofdrilling or punching and flame cutting shall generally benot more than 1 ⁄32 inch greater than the nominal width. Theflame cut surface shall be ground smooth.

11.4.8.2 Accuracy of Hole Group

11.4.8.2.1 Accuracy Before Reaming

All holes punched full size, subpunched, or subdrilledshall be so accurately punched that after assembling (be-fore any reaming is done) a cylindrical pin 1 ⁄8 inch smallerin diameter than the nominal size of the punched hole maybe entered perpendicular to the face of the member, with-out drifting, in at least 75% of the contiguous holes in thesame plane. If the requirement is not fulfilled, the badlypunched pieces will be rejected. If any hole will not passa pin 3⁄ 16 inch smaller in diameter than the nominal size ofthe punched hole, this will be cause for rejection.

11.4.8.2.2 Accuracy After Reaming

When holes are reamed or drilled, 85% of the holes inany contiguous group shall, after reaming or drilling,show no offset greater than 1 ⁄32 inch between adjacentthicknesses of metal.

All steel templates shall have hardened steel bushingsin holes accurately dimensioned from the center lines ofthe connection as inscribed on the template. The centerlines shall be used in locating accurately the templatefrom the milled or scribed ends of the members.

11.4.8.3 Numerically Controlled Drilled FieldConnections

In lieu of subsized holes and reaming while assembled,or drilling holes full-size while assembled, the Contractorshall have the option to drill or punch bolt holes full-sizein unassembled pieces and/or connections including tem-plates for use with matching subsized and reamed holes,by means of suitable numerically controlled (N/C) drillingor punching equipment. Full-sized punched holes shallmeet the requirements of Article 11.4.8.1.

If N/C drilling or punching equipment is used, the Con-tractor, by means of check assemblies, will be required todemonstrate the accuracy of this drilling or punching pro-cedure in accordance with the provisions of Article11.5.3.3.

Holes drilled or punched by N/C equipment shall bedrilled or punched to appropriate size either through indi-vidual pieces, or drilled through any combination ofpieces held tightly together.

11.4.8.4 Holes for Ribbed Bolts, Turned Bolts, orOther Approved Bearing Type Bolts

All holes for ribbed bolts, turned bolts, or other ap-proved bearing-type bolts shall be subpunched or sub-drilled 3⁄ 16 inch smaller than the nominal diameter of the



bolt and reamed when assembled, or drilled to a steeltemplate or, after assembling, drilled from the solid at theoption of the Fabricator. In any case the finished holesshall provide a driving fit as specified on the plans or inthe special provisions.

11.4.8.5 Preparation of Field Connections

Holes in all field connections and field splices of mainmember of trusses, arches, continuous beam spans, bents,towers (each face), plate girders, and rigid frames shallbe subpunched or subdrilled and subsequently reamedwhile assembled or drilled full size through a steel tem-plate while assembled. Holes for field splices of rolledbeam stringers continuous over floor beams or crossframes may be drilled full size unassembled to a steeltemplate. All holes for floor beams or cross frames maybe drilled full size unassembled to a steel template, ex-cept that all holes for floor beam and stringer field endconnections shall be subpunched and reamed while as-sembled or drilled full size to a steel template. Reamingor drilling full size of field connection holes through asteel template shall be done after the template has beenlocated with utmost care as to position and angle andfirmly bolted in place. Templates used for reamingmatching members, or the opposite faces of a singlemember shall be exact duplicates. Templates used forconnections on like parts or members shall be so accu-rately located that the parts or members are duplicatesand require no match-marking.

For any connection, in lieu of subpunching and ream-ing or subdrilling and reaming, the fabricator may, at hisoption, drill holes full size with all thicknesses or mate-rial assembled in proper position.

11.4.9 Pins and Rollers

11.4.9.1 General

Pins and rollers shall be accurately turned to thedimensions shown on the drawings and shall be straight,smooth, and free from flaws. Pins and rollers more than 9 inches in diameter shall be forged and annealed. Pinsand rollers 9 inches or less in diameter may be eitherforged and annealed or cold-finished carbon-steelshafting.

In pins larger than 9 inches in diameter, a hole not lessthan 2 inches in diameter shall be bored full length alongthe axis after the forging has been allowed to cool to atemperature below the critical range, under suitable con-ditions to prevent injury by too rapid cooling, and beforebeing annealed.

11.4.9.2 Boring Pin Holes

Pin holes shall be bored true to the specified diameter,smooth and straight, at right angles with the axis of themember and parallel with each other unless otherwiserequired. The final surface shall be produced by a finish-ing cut.

The diameter of the pin hole shall not exceed that of thepin by more than 1 ⁄50 inch for pins 5 inches or less indiameter, or by 1 ⁄32 inch for larger pins.

The distance outside to outside of end holes in tensionmembers and inside to inside of end holes in compressionmembers shall not vary from that specified more than 1 ⁄32

inch. Boring of pin holes in built-up members shall bedone after the member has been assembled.

11.4.9.3 Threads for Bolts and Pins

Threads for all bolts and pins for structural steel con-struction shall conform to the United Standard SeriesUNC ANSI B1.1, Class 2A for external threads and Class2B for internal threads, except that pin ends having a di-ameter of 13 ⁄8 inches or more shall be threaded six threadsto the inch.

11.4.10 Eyebars

Pin holes may be flame cut at least 2 inches smaller indiameter than the finished pin diameter. All eyebars thatare to be placed side by side in the structure shall be se-curely fastened together in the order that they will beplaced on the pin and bored at both ends while soclamped. Eyebars shall be packed and match-marked forshipment and erection. All identifying marks shall bestamped with steel stencils on the edge of one head ofeach member after fabrication is completed so as to be vis-ible when the bars are nested in place on the structure.Steel die stamps shall be low stress type. No welding is al-lowed on eyebars or to secure adjacent eyebars.

The eyebars shall be straight and free from twists andthe pin holes shall be accurately located on the center lineof the bar. The inclination of any bar to the plane of thetruss shall not exceed 1 ⁄16 inch to a foot.

The edges of eyebars that lie between the transversecenter line of their pin holes shall be cut simultaneouslywith two mechanically operated torches abreast of eachother, guided by a substantial template, in such a manneras to prevent distortion of the plates.

11.4.11 Annealing and Stress Relieving

Structural members which are indicated in the contractto be annealed or normalized shall have finished machin-



ing, boring, and straightening done subsequent to heattreatment. Normalizing and annealing (full annealing)shall be as specified in ASTM E 44. The temperaturesshall be maintained uniformly throughout the furnace dur-ing the heating and cooling so that the temperature at notwo points on the member will differ by more than 100°Fat any one time.

Members of AASHTO M 270 (ASTM A 709) Grades100/100W or Grade 70W steels shall not be annealed ornormalized and shall be stress relieved only with the ap-proval of the Engineer.

A record of each furnace charge shall identify thepieces in the charge and show the temperatures and sched-ule actually used. Proper instruments, including recordingpyrometers, shall be provided for determining at any timethe temperatures of members in the furnace. The recordsof the treatment operation shall be available to and meetthe approval of the Engineer. The holding temperature forstress relieving Grades HPS70W and 100/100W shall notexceed 1,100°F and for Grade 70W shall not exceed1,050°F.

Members, such as bridge shoes, pedestals, or otherparts that are built up by welding sections of plate togethershall be stress relieved in accordance with the procedureof Section 4.4 of the current ANSI/AASHTO/AWS D1.5Bridge Welding Code, when required by the plans, speci-fications, or special provisions governing the contract.

11.4.12 Curved Girders

11.4.12.1 General

Flanges of curved, welded girders may be cut to theradii shown on the plans or curved by applying heat asspecified in the succeeding articles providing the radii isnot less than allowed by Article 10.15.2 of Division I.

11.4.12.2 Heat Curving Rolled Beams andWelded Girders

11.4.12.2.1 Materials

Except for Grade HPS70W steel, steels that are manu-factured to a specified minimum yield point greater than50,000 psi shall not be heat curved.

11.4.12.2.2 Type of Heating

Beams and girders may be curved by either continuousor V-type heating as approved by the Engineer. For thecontinuous method, a strip or intermittent strips along theedge of the top and bottom flange shall be heated approx-imately simultaneously depending on flange widths andthicknesses; the strip shall be of sufficient width and tem-

perature to obtain the required curvature. For the V-typeheating, the top and bottom flanges shall be heated in trun-cated triangular or wedge-shaped areas having their basealong the flange edge and spaced at regular intervals alongeach flange; the spacing and temperature shall be as re-quired to obtain the required curvature, and heating shallprogress along the top and bottom flange at approximatelythe same rate.

For the V-type heating, the apex of the truncated trian-gular area applied to the inside flange surface shall termi-nate just before the juncture of the web and the flange isreached. To avoid unnecessary web distortion, specialcare shall be taken when heating the inside flange surfaces(the surfaces that intersect the web) so that heat is not ap-plied directly to the web. When the radius of curvature is1,000 feet or more, the apex of the truncated triangularheating pattern applied to the outside flange surface shallextend to the juncture of the flange and web. When the ra-dius of curvature is less than 1,000 feet, the apex of thetruncated triangular heating pattern applied to the outsideflange surface shall extend past the web for a distanceequal to one-eighth of the flange width or 3 inches,whichever is less. The truncated triangular pattern shallhave an included angle of approximately 15 to 30°, but thebase of the triangle shall not exceed 10 inches. Variationsin the patterns prescribed above may be made with the ap-proval of the Engineer.

For both types of heating, the flange edges to be heatedare those that will be on the inside of the horizontal curveafter cooling. Heating both inside and outside flange sur-faces is only mandatory when the flange thickness is 11 ⁄4inches or greater, in which case, the two surfaces shall beheated concurrently. The maximum temperature shall beprescribed as follows.

11.4.12.2.3 Temperature

The heat-curving operation shall be conducted in sucha manner that the temperature of the steel does not exceed1,200°F for Grades 36, 50 and 50W; 1,100°F for GradesHPS70W and 100/100W; and 1,050°F for Grade 70W asmeasured by temperature indicating crayons or other suit-able means. The girder shall not be artificially cooled untilafter naturally cooling to 600°F. The method of artificialcooling is subject to the approval of the Engineer.

11.4.12.2.4 Position for Heating

The girder may be heat-curved with the web in eithera vertical or a horizontal position. When curved in the ver-tical position, the girder must be braced or supported insuch a manner that the tendency of the girder to deflect lat-erally during the heat-curving process will not cause thegirder to overturn.



When curved in the horizontal position, the girdermust be supported near its ends and at intermediatepoints, if required, to obtain a uniform curvature; thebending stress in the flanges due to the dead weight of thegirder and externally applied loads must not exceed theusual allowable design stress. When the girder is posi-tioned horizontally for heating, intermediate safety catchblocks must be maintained at the mid-length of the girderwithin 2 inches of the flanges at all times during the heat-ing process to guard against a sudden sag due to plasticflange buckling.

11.4.12.2.5 Sequence of Operations

The girder shall be heat-curved in the fabrication shop before it is painted. The heat curving operation maybe conducted either before or after all the requiredwelding of transverse intermediate stiffeners is com-pleted. However, unless provisions are made for girdershrinkage, connection plates and bearing stiffeners shallbe located and attached after heat curving. If longitudinalstiffeners are required, they shall be heat-curved oroxygen-cut separately and then welded to the curvedgirder. When cover plates are to be attached to rolledbeams, they may be attached before heat curving if thetotal thickness of one flange and cover plate is less than21⁄ 2 inches and the radius of curvature is greater than1,000 feet. For other rolled beams with cover plates, the beams must be heat-curved before the cover plates are attached; cover plates must be either heat curved oroxygen-cut separately and then welded to the curvedbeam.

11.4.12.2.6 Camber

Girders shall be cambered before heat curving.Camber for rolled beams may be obtained by heat-cambering methods approved by the Engineer. For plate girders, the web shall be cut to the prescribed cam-ber with suitable allowance for shrinkage due to cutting,welding, and heat curving. However, subject to theapproval of the Engineer, moderate deviations fromspecified camber may be corrected by a carefully super-vised application of heat.

11.4.12.2.7 Measurement of Curvature and Camber

Horizontal curvature and vertical camber shall bemeasured for final acceptance after all welding and heat-ing operations are completed and the flanges have cooledto a uniform temperature. Horizontal curvature shall bechecked with the girder in the vertical position.

11.4.13 Orthotropic-Deck Superstructures

11.4.13.1 General

Dimensional tolerance limits for orthotropic-deckbridge members shall be applied to each completed but unloaded member and shall be as specified in Arti-cle 3.5 of the current ANSI/AASHTO/AWS D1.5 BridgeWelding Code except as follows. The deviation from de-tailed flatness, straightness, or curvature at any pointshall be the perpendicular distance from that point to atemplate edge which has the detailed straightness or cur-vature and which is in contact with the element at twoother points. The term element as used herein refers toindividual panels, stiffeners, flanges, or other pieces.The template edge may have any length not exceedingthe greatest dimension of the element being examinedand, for any panel, not exceeding 1.5 times the least dimension of the panel; it may be placed anywherewithin the boundaries of the element. The deviation shallbe measured between adjacent points of contact of thetemplate edge with the element; the distance betweenthese adjacent points of contact shall be used in the for-mulas to establish the tolerance limits for the segmentbeing measured whenever this distance is less than theapplicable dimension of the element specified for theformula.

11.4.13.2 Flatness of Panels

(a) The term “panel” as used in this article means aclear area of steel plate surface bounded by stiffeners,webs, flanges, or plate edges and not further subdividedby any such elements. The provisions of this article applyto all panels in the bridge; for plates stiffened on one sideonly such as orthotropic-deck plates or flanges of boxgirders, this includes the total clear width on the side with-out stiffeners as well as the panels between stiffeners onthe side with stiffeners.

(b) The maximum deviation from detailed flatness orcurvature of a panel shall not exceed the greater of:

where,

D � the least dimension in inches along the bound-ary of the panel

T � the minimum thickness in inches of the platecomprising the panel.

316 inch or

D

144 T⁄ inch



11.4.13.3 Straightness of Longitudinal StiffenersSubject to Calculated CompressiveStress, Including Orthotropic-DeckRibs

The maximum deviation from detailed straightness orcurvature in any direction perpendicular to its length of alongitudinal web stiffener or other stiffener subject to cal-culated compressive stress shall not exceed:

where L � the length of the stiffener or rib between crossmembers, webs, or flanges, in inches.

11.4.13.4 Straightness of Transverse WebStiffeners and Other Stiffeners notSubject to Calculated CompressiveStress

The maximum deviation from detailed straightness orcurvature in any direction perpendicular to its length of atransverse web stiffener or other stiffener not subject tocalculated compressive stress shall not exceed:

where L � the length of the stiffener between cross mem-bers, webs, or flanges, in inches.

11.4.14 Full-Sized Tests

When full-sized tests of fabricated structural membersor eyebars are required by the contract, the Contractorshall provide suitable facilities, material, supervision, andlabor necessary for making and recording the requiredtests. The members tested in accordance with the contractshall be paid for in accordance with Article 11.7.2.

11.4.15 Marking and Shipping

Each member shall be painted or marked with an erec-tion mark for identification and an erection diagram show-ing these marks shall be furnished to the Engineer.

The Contractor shall furnish to the Engineer as manycopies of material orders, shipping statements, and erec-tion diagrams as the Engineer may direct. The weights ofthe individual members shall be shown on the statements.Members weighing more than 3 tons shall have theweights marked thereon. Structural members shall beloaded on trucks or cars in such a manner that they may betransported and unloaded at their destination without being

excessively stressed, deformed, or otherwise damaged.Bolts, nuts and washers (where required) from each ro-

tational-capacity lot shall be shipped in the same con-tainer. If there is only one production lot number for eachsize of nut and washer, the nuts and washers may beshipped in separate containers. Pins, small parts and pack-ages of bolts, washers, and nuts shall be shipped in boxes,crates, kegs, or barrels, but the gross weight of any pack-age shall not exceed 300 pounds. A list and description ofthe contained materials shall be plainly marked on the out-side of each shipping container.

11.5 ASSEMBLY

11.5.1 Bolting

Surfaces of metal in contact shall be cleaned before as-sembling. The parts of a member shall be assembled, wellpinned, and firmly drawn together before drilling, ream-ing, or bolting is commenced. Assembled pieces shall betaken apart, if necessary, for the removal of burrs andshavings produced by the operation. The member shall befree from twists, bends, and other deformation.

The drifting done during assembling shall be only suchas to bring the parts into position and not sufficient to en-large the holes or distort the metal.

11.5.2 Welded Connections

Surfaces and edges to be welded shall be smooth, uni-form, clean and free of defects which would adversely af-fect the quality of the weld. Edge preparation shall bedone in accordance with the current ANSI/AASHTO/AWSD1.5 Bridge Welding Code.

11.5.3 Preassembly of Field Connections

11.5.3.1 General

Field connections of main members of trusses, arches,continuous beams, plate girders, bents, towers and rigidframes shall be preassembled prior to erection as nec-essary to verify the geometry of the completed structureor unit and to verify or prepare field splices. Attainingaccurate geometry is the responsibility of the Contractorwho shall propose an appropriate method of preassemblyfor approval by the Engineer. The method and details ofpreassembly shall be consistent with the erection proce-dure shown on the erection plans and camber diagramsprepared by the Contractor and approved by the Engi-neer. As a minimum, the preassembly procedure shallconsist of assembling three contiguous panels accurately

L

240

L

480



adjusted for line and camber. Successive assembliesshall consist of at least one section or panel of the previ-ous assembly (repositioned if necessary and adequatelypinned to assure accurate alignment) plus two or moresections or panels added at the advancing end. In thecase of structures longer than 150 feet, each assemblyshall be not less than 150 feet long regardless of the lengthof individual continuous panels or sections. At the optionof the fabricator, sequence of assembly may start from anylocation in the structure and proceed in one or both direc-tions so long as the preceding requirements are satisfied.

11.5.3.2 Bolted Connections

For bolted connections holes shall be prepared as out-lined in Article 11.4.8. Where applicable, major compo-nents shall be assembled with milled ends of compressionmembers in full bearing and then shall have their subsizedholes reamed to the specified size while the connectionsare assembled.

11.5.3.3 Check Assembly—NumericallyControlled Drilling

When the contractor elects to use numericallycontrolled drilling, a check assembly shall be required for each major structural type of each project, unlessotherwise designated on the plans or in the specialprovisions, and shall consist of at least three contiguousshop sections or, in a truss, all members in at least threecontiguous panels but not less than the number of panelsassociated with three contiguous chord lengths (i.e.,length between field splices). Check assemblies should bebased on the proposed order of erection, joints in bearings,special complex points, and similar considerations.Special points could be the portals of skewed trusses, forexample.

The check assemblies shall preferably be the first sec-tions of each major structural type to be fabricated.

Shop assemblies other than the check assemblies willnot be required.

If the check assembly fails in some specific manner todemonstrate that the required accuracy is being obtained,further check assemblies may be required by the Engineerfor which there shall be no additional cost to the Depart-ment.

Each assembly, including camber, alignment, accuracyof holes, and fit of milled joints, shall be approved by theEngineer before reaming is commenced or before an N/Cdrilled check assembly is dismantled.

11.5.3.4 Field Welded Connections

For field welded connections the fit of members in-cluding the proper space between abutting flanges shall beprepared or verified with the segment preassembled in ac-cordance with Article 11.5.3.1.

11.5.4 Match Marking

Connecting parts preassembled in the shop to assureproper fit in the field shall be match-marked, and adiagram showing such marks shall be furnished to theEngineer.

11.5.5 Connections Using Unfinished, Turned orRibbed Bolts

11.5.5.1 General

When unfinished bolts are specified, the bolts shall beunfinished, turned, or ribbed bolts conforming to the re-quirements for Grade A Bolts of Standard Specificationfor Carbon Steel Bolts and Studs, 60,000 PSI TensileStrength, ASTM A 307. Bolts shall have single self-lock-ing nuts or double nuts unless otherwise shown on theplans or in the special provisions. Beveled washers shallbe used where bearing faces have a slope of more than1:20 with respect to a plane normal to the bolt axis. Thespecifications of this article do not pertain to the use ofhigh-strength bolts. Bolted connections fabricated withhigh-strength bolts shall conform to Article 11.5.6.

11.5.5.2 Turned Bolts

The surface of the body of turned bolts shall meet theANSI roughness rating value of 125. Heads and nuts shallbe hexagonal with standard dimensions for bolts of thenominal size specified or the next larger nominal size. Di-ameter of threads shall be equal to the body of the bolt orthe nominal diameter of the bolt specified. Holes for turnedbolts shall be carefully reamed with bolts furnished to pro-vide for a light driving fit. Threads shall be entirely outsideof the holes. A washer shall be provided under the nut.

11.5.5.3 Ribbed Bolts

The body of ribbed bolts shall be of an approved formwith continuous longitudinal ribs. The diameter of thebody measured on a circle through the points of the ribsshall be 5 ⁄64 inch greater than the nominal diameter speci-fied for the bolts.

Ribbed bolts shall be furnished with round heads con-forming to ANSI B 18.5 unless otherwise specified. Nutsshall be hexagonal, either recessed or with a washer ofsuitable thickness. Ribbed bolts shall make a driving fit



with the holes. The hardness of the ribs shall be such thatthe ribs do not mash down enough to permit the bolts toturn in the holes during tightening. If for any reason thebolt twists before drawing tight, the hole shall be carefullyreamed and an oversized bolt used as a replacement.

11.5.6 Connections Using High-Strength Bolts

11.5.6.1 General

This article covers the assembly of structural jointsusing AASHTO M 164 (ASTM A 325) or AASHTO M253 (ASTM A 490) high-strength bolts, or equivalent fas-teners, installed so as to develop the minimum requiredbolt tension specified in Table 11.5A. The bolts are usedin holes conforming to the requirements of Article 11.4.8.

11.5.6.2 Bolted Parts

All material within the grip of the bolt shall be steel,there shall be no compressible material such as gaskets orinsulation within the grip. Bolted steel parts shall fitsolidly together after the bolts are snugged, and may becoated or uncoated. The slope of the surfaces of parts incontact with the bolt head or nut shall not exceed 1:20with respect to a plane normal to the bolt axis.

11.5.6.3 Surface Conditions

At the time of assembly, all joint surfaces, including sur-faces adjacent to the bolt head and nut, shall be free of scale,except tight mill scale, and shall be free of dirt or other for-eign material. Burrs that would prevent solid seating of theconnected parts in the snug condition shall be removed.

Paint is permitted on the faying surface including slipcritical joints when designed in accordance with Articles10.32.3, or 10.56.1.3, Division I.

The faying surfaces of slip-critical connections shall meetthe requirements of the following paragraphs, as applicable:

(1) In noncoated joints, paint, including any inadver-tent overspray, shall be excluded from areas closer thanone-bolt diameter, but not less than 1 inch, from the edgeof any hole and all areas within the bolt pattern.

(2) Joints specified to have painted faying surfacesshall be blast cleaned and coated with a paint which hasbeen qualified in accordance with requirements of Articles10.32.3.2.3 or 10.57.3.3, Division I.

(3) Coated joints shall not be assembled before thecoating has cured for the minimum time used in the qual-ifying test.

(4) Faying surfaces specified to be galvanized shall behot-dip galvanized in accordance with AASHTO M 111(ASTM A 123), and shall subsequently be roughened bymeans of hand wire brushing. Power wire brushing is notpermitted.

11.5.6.4 Installation

11.5.6.4.1 General

Fastener components shall be assigned lot numbers (including rotational-capacity lot numbers) prior to ship-ping, and components shall be assembled when installed.Such components shall be protected from dirt and moistureat the job site. Remove from protective storage only thenumber of anticipated components to be installed during awork shift. Components not used shall be returned to pro-tected storage at the end of the shift. Components shall notbe cleaned of lubricant that is required to be present in as-delivered condition. Assemblies for slip-critical connec-tions which accumulate rust or dirt resulting from job siteconditions shall be cleaned, relubricated and tested for ro-tational-capacity prior to installation. All galvanized nutsshall be lubricated with a lubricant containing a visibledye. Plain bolts must be “oily” to touch when deliveredand installed. Lubricant on exposed surfaces shall be re-moved prior to painting.

A bolt tension measuring device (a Skidmore-WilhelmCalibrator or other acceptable bolt tension indicating de-vice) shall be at all job sites where high-strength bolts arebeing installed and tensioned. The tension measuring de-vice shall be used to perform the rotational-capacity testand to confirm (1) the suitability to satisfy the require-ments of Table 11.5A of the complete fastener assembly,including lubrication if required to be used in the work,(2) calibration of the wrenches, if applicable, and (3) theunderstanding and proper use by the bolting crew of the


TABLE 11.5A Required Fastener TensionMinimum Bolt Tension in Pounds*


installation method. To perform the calibrated wrenchverification test for short grip bolts, direct tension indica-tors (DTI) with solid plates may be used in lieu of a ten-sion measuring device. The DTI lot shall be first verifiedwith a longer grip bolt in the Skidmore-Wilhelm Calibra-tor or an acceptable equivalent device. The frequency ofconfirmation testing, the number of tests to be performed,and the test procedure shall be as specified in Articles11.5.6.4.4 through 11.5.6.4.7, as applicable. The accuracyof the tension measuring device shall be confirmed by anapproved testing agency at least annually.

Bolts and nuts together with washers of size and qualityspecified, located as required below, shall be installed inproperly aligned holes and tensioned and inspected by anyof the installation methods described in Articles 11.5.6.4.4through 11.5.6.4.7 to at least the minimum tension speci-fied in Table 11.5A. Tensioning may be done by turning thebolt while the nut is prevented from rotating when it is im-practical to turn the nut. Impact wrenches, if used, shall beof adequate capacity and sufficiently supplied with air totension each bolt in approximately 10 seconds.

AASHTO M 253 (ASTM A 490) fasteners and galva-nized AASHTO M 164 (ASTM A 325) fasteners shall notbe reused. Other AASHTO M 164 (ASTM A 325) boltsmay be reused if approved by the Engineer. Touching upor retensioning previously tensioned bolts which mayhave been loosened by the tensioning of adjacent boltsshall not be considered as reuse provided the tensioningcontinues from the initial position and does not requiregreater rotation, including the tolerance, than that requiredby Table 11.5B.

Bolts shall be installed in all holes of the connection and the connection brought to a snug condition. Snug is de-fined as having all plies of the connection in firm contact.

Snugging shall progress systematically from the mostrigid part of the connection to the free edges. The snug-ging sequence shall be repeated until the full connectionis in a snug condition.

11.5.6.4.2 Rotational-Capacity Tests

Rotational-capacity testing is required for all fastenerassemblies. Galvanized assemblies shall be tested galva-nized. Washers are required as part of the test even thoughthey may not be required as part of the installation proce-dure. The following shall apply:

(a) Except as modified herein, the rotational-capacitytest shall be performed in accordance with the require-ments of AASHTO M 164 (ASTM A 325).(b) Each combination of bolt production lot, nut lotand washer lot shall be tested as an assembly. Wherewashers are not required by the installation procedures,they need not be included in the lot identification.

(c) A rotational-capacity lot number shall have beenassigned to each combination of lots tested.(d) The minimum frequency of testing shall be twoassemblies per rotational-capacity lot.(e) For bolts that are long enough to fit in a Skidmore-Wilhelm Calibrator, the bolt, nut and washer assemblyshall be assembled in a Skidmore-Wilhelm Calibratoror an acceptable equivalent device.(f) Bolts that are too short to be tested in a Skidmore-Wilhelm Calibrator may be tested in a steel joint. Thetension requirement, in (g) below, need not apply. Themaximum torque requirement, torque � 0.25 PD, shallbe computed using a value of P equal to the turn testtension taken as 1.15 times the bolt tension in Table11.5A.(g) The tension reached at the below rotation (i.e., turn-test tension) shall be equal to or greater than 1.15 timesthe required fastener tension (i.e., installation tension)shown in Table 11.5A.


TABLE 11.5B Nut Rotation from the Snug-TightCondition Geometry of Outer Faces of Bolted Partsa,b


(h) The minimum rotation from an initial tension of10% of the minimum required tension (snug condition)shall be two times the required number of turns indi-cated in Table 11.5B without stripping or failure.(i) After the required installation tension listed abovehas been exceeded, one reading of tension and torqueshall be taken and recorded. The torque value shallconform to the following:

Torque � 0.25 PD

Where:

Torque � measured torque (foot-pounds)P � measured bolt tension (pounds)D � bolt diameter (feet).

11.5.6.4.3 Requirement for Washers

Where the outer face of the bolted parts has a slopegreater than 1:20 with respect to a plane normal to the boltaxis, a hardened beveled washer shall be used to com-pensate for the lack of parallelism.

Hardened beveled washers for American StandardBeams and Channels shall be required and shall besquare or rectangular, shall conform to the requirementsof AASHTO M 293 (ASTM F 436), and shall taper inthickness.

Where necessary, washers may be clipped on one sideto a point not closer than 7⁄ 8 of the bolt diameter from thecenter of the washer.

Hardened washers are not required for connectionsusing AASHTO M 164 (ASTM A 325) and AASHTO M253 (ASTM A 490) bolts except as follows:

• Hardened washers shall be used under the turnedelement when tensioning is to be performed by cal-ibrated wrench method.

• Irrespective of the tensioning method, hardenedwashers shall be used under both the head and thenut when AASHTO M 253 (ASTM A 490) boltsare to be installed in material having a specifiedyield point less than 40 ksi. However, when DTIsare used they may replace a hardened washer pro-vided a standard hole is used.

• Where AASHTO M 164 (ASTM A 325) bolts ofany diameter or AASHTO M 253 (ASTM A 490)bolts equal to or less than 1 inch in diameter are tobe installed in oversize or short-slotted holes in anouter ply, a hardened washer conforming toAASHTO M 293 (ASTM F 436) shall be used.

• When AASHTO M 253 (ASTM A 490) bolts over1 inch in diameter are to be installed in an oversizedor short-slotted hole in an outer ply, hardened wash-ers conforming to AASHTO M 293 (ASTM F 436)except with 5 ⁄16 inch minimum thickness shall be

used under both the head and the nut in lieu of stan-dard thickness hardened washers. Multiple hard-ened washers with combined thickness equal to orgreater than 5 ⁄16 inch do not satisfy this requirement.

• Where AASHTO M 164 (ASTM A 325) bolts ofany diameter or AASHTO M 253 (ASTM A 490)bolts equal to or less than 1 inch in diameter are tobe installed in a long slotted hole in an outer ply, aplate washer or continuous bar of at least 5⁄ 16 inchthickness with standard holes shall be provided.These washers or bars shall have a size sufficient tocompletely cover the slot after installation and shallbe of structural grade material, but need not behardened except as follows. When AASHTO M253 (ASTM A 490) bolts over 1 inch in diameterare to be used in long slotted holes in external plies,a single hardened washer conforming to AASHTOM 293 (ASTM F 436) but with 5 ⁄16 inch minimumthickness shall be used in lieu of washers or bars ofstructural grade material. Multiple hardened wash-ers with combined thickness equal to or greaterthan 5⁄16 inch do not satisfy this requirement.

Alternate design fasteners meeting the requirements ofArticle 11.3.2.6 with a geometry which provides a bear-ing circle on the head or nut with a diameter equal to orgreater then the diameter of hardened washers meeting therequirements of AASHTO M 293 (ASTM F 436) satisfythe requirements for washers specified herein and may beused without washers.

11.5.6.4.4 Turn-of-Nut Installation Method

When the turn-of-nut installation method is used,hardened washers are not required except as may be spec-ified in Article 11.5.6.4.3.

Verification testing using a representative sample of notless than three fastener assemblies of each diameter, lengthand grade to be used in the work shall be performed at thestart of work in a device capable of indicating bolt tension.This verification test shall demonstrate that the method usedto develop a snug condition and control the turns from snugby the bolting crew develops a tension not less than 5%greater than the tension required by Table 11.5A. Periodicretesting shall be performed when ordered by the Engineer.

After snugging, the applicable amount of rotation spec-ified in Table 11.5B shall be achieved. During the tension-ing operation there shall be no rotation of the part notturned by the wrench. Tensioning shall progress systemat-ically from the most rigid part of the joint to its free edges.

11.5.6.4.5 Calibrated Wrench Installation Method

The calibrated wrench method may be used only whenwrenches are calibrated on a daily basis and when a hard-ened washer is used under the turned element. Standard



torques determined from tables or from formulas which areassumed to relate torque to tension shall not be acceptable.

When calibrated wrenches are used for installation,they shall be set to deliver a torque which has been cali-brated to develop a tension not less than 5% in excess ofthe minimum tension specified in Table 11.5A. The instal-lation procedures shall be calibrated by verification testingat least once each working day for each fastener assemblylot that is being installed that day in the work. This verifi-cation testing shall be accomplished in a tension measur-ing device capable of indicating actual bolt tension by test-ing three typical fastener assemblies from each lot. Bolts,nuts and washers under the turned element shall be sam-pled from production lots. Wrenches shall be recalibratedwhen significant difference is noted in the surface condi-tion of the bolts, threads, nuts or washers. It shall be veri-fied during actual installation in the assembled steel workthat the wrench adjustment selected by the calibration doesnot produce a nut or bolt head rotation from a snug condi-tion greater than that permitted in Table 11.5B. If manualtorque wrenches are used, nuts shall be torqued in the ten-sioning direction when torque is measured.

When calibrated wrenches are used to install and ten-sion bolts in a connection, bolts shall be installed withhardened washers under the turned element. Followingsnugging, the connection shall be tensioned using the cal-ibrated wrench. Tensioning shall progress systematicallyfrom the most rigid part of the joint to its free edges. Thewrench shall be returned to “touch up” previously ten-sioned bolts which may have been relaxed as a result ofthe subsequent tensioning of adjacent bolts until all boltsare tensioned to the prescribed amount.

11.5.6.4.6 Alternative Design Bolts InstallationMethod

When fasteners which incorporate a design feature in-tended to indirectly indicate that the applied torque devel-ops the required tension or to automatically develop the ten-sion required by Table 11.5Aand which have been qualifiedunder Article 11.3.2.5 are to be installed, verification test-ing using a representative sample of not less than three fas-tener assemblies of each diameter, length and grade to beused in the work shall be performed at the job site in a de-vice capable of indicating bolt tension. The test assemblyshall include flat-hardened washers, if required in the actualconnection, arranged as in the actual connections to be ten-sioned. The verification test shall demonstrate that each boltdevelops a tension not less than 5% greater than the tensionrequired by Table 11.5A. Manufacturer’s installation pro-cedure shall be followed for installation of bolts in the cal-ibration device and in all connections. Periodic retestingshall be performed when ordered by the Engineer.

When alternate design fasteners which are intended tocontrol or indicate bolt tension of the fasteners are used,

bolts shall be installed in all holes of the connection andinitially snugged sufficiently to bring all plies of the jointinto firm contact but without yielding or fracturing the con-trol or indicator element of the fasteners. All fasteners shallthen be further tensioned, progressing systematically fromthe most rigid part of the connection to the free edges in amanner that will minimize relaxation of previously ten-sioned bolts. In some cases, proper tensioning of the boltsmay require more than a single cycle of systematic partialtensioning prior to final yielding or fracturing of the con-trol or indicator element of individual fasteners. If yield-ing or twist-off occurs prior to the final tensioning cycle,the fastener assembly shall be replaced with a new one.

11.5.6.4.7 Direct Tension Indicator InstallationMethod

When Direct Tension Indicators (DTIs) meeting the re-quirements of Article 11.3.2.6 are to be used with high-strength bolts to indicate bolt tension, they shall be sub-jected to the verification testing described below andinstalled in accordance with the method specified below.Unless otherwise approved by the engineer-of-record, theDTIs shall be installed under the head of the bolt and thenut turned to tension the bolt. The Manufacturer’s recom-mendations shall be followed for the proper orientation ofthe DTI and additional washers, if any, required for thecorrect use of the DTI. Installation of a DTI under theturned element may be permitted if a washer separates theturned element from the DTI.

11.5.6.4.7a Verification

Verification testing shall be performed in a calibratedbolt tension measuring device. A special flat insert shallbe used in place of the normal bolt head holding insert.Three verification tests are required for each combinationof fastener assembly rotational-capacity lot, DTI lot, andDTI position relative to the turned element (bolt head ornut) to be used on the project. The fastener assembly shallbe installed in the tension measuring device with the DTIlocated in the same position as in the work. The elementnot turned (bolt or nut) shall be restrained from rotation.The purpose of verification testing is to ensure that the fas-tener will be at or above the desired installation tensionwhen the requisite number of spaces between the protru-sions have a gap of 0.005 inches or less and that the boltwill not have excessive plastic deformation at the mini-mum gap allowed on the project.

The verification tests shall be conducted in two stages.The bolt nut and DTI assembly shall be installed in a man-ner so that at least three and preferably not more than fivethreads are located between the bearing face of the nut andthe bolt head. The bolt shall be tensioned first to the loadequal to that listed in Table 11.5C under Verification Ten-



sion for the grade and diameter of bolt. If an impact wrenchis used, the tension developed using the impact wrenchshall be no more than two-thirds the required tension. Sub-sequently a manual wrench shall be used to attain the re-quired tension. The number of refusals of a 0.005 inch tapered feeler gauge in the spaces between the protrusionsshall be recorded. The number of refusals for uncoatedDTIs under the stationary or turned element, or coatedDTIs under the stationary element, shall not exceed thenumber listed under Maximum Verification Refusals inTable 11.5C for the grade and diameter of bolt used. Themaximum number of verification refusals for coated DTIs(galvanized, painted, or epoxy-coated), when used underthe turned element shall be no more than the number ofspaces on the DTI less one. The DTI lot is rejected if thenumber of refusals exceeds the values in the table or, forcoated DTIs if the gauge is refused in all spaces.

After the number of refusals is recorded at the ver-ification load, the bolt shall be further tensioned until the0.005 inch feeler gauge is refused at all the spaces and avisible gap exists in at least one space. The load at thiscondition shall be recorded and the bolt removed fromthe tension measuring device. The nut shall be able to berundown by hand for the complete thread length of thebolt excluding thread runout. If the nut cannot be run-down for this thread length, the DTI lot shall be rejectedunless the load recorded is less than 95% of the averageload measured in the rotational capacity test for the fas-tener lot as specified in Article 11.5.6.4.2g.

If the bolt is too short to be tested in the calibration de-vice, the DTI lot shall be verified on a long bolt in a cali-brator to determine the number of refusals at the Verifica-tion Tension listed in Table 11.5C. The number of refusalsshall not exceed the values listed under Maximum Verifi-cation Refusals in Table 11.5C. Another DTI from the samelot shall then be verified with the short bolt in a convenienthole in the work. The bolt shall be tensioned until the 0.005inch feeler gauge is refused in all spaces and a visible gapexists in at least one space. The bolt shall then be removedfrom the tension measuring device and the nut must be ableto be rundown by hand for the complete thread length ofthe bolt excluding thread runout. The DTI lot shall be re-jected if the nut cannot be rundown for this thread length.

11.5.6.4.7b Installation

Installation of fastener assemblies using DTIs shall be performed in two stages. The stationary element shallbe held against rotation during each stage of the installa-tion. The connection shall be first snugged with boltsinstalled in all the holes of the connection and tensionedsufficiently to bring all the plies of the connection intofirm contact. The number of spaces in which 0.005 inchfeeler gauge is refused in the DTI after snugging shall notexceed those listed under Maximum Verification Re-fusals in Table 11.5C. If the number exceeds the valuesin the table, the fastener assembly shall be removed andanother DTI installed and snugged.

For uncoated DTIs under the stationary or turned ele-ment, or coated DTIs under the stationary element, the boltsshall be further tensioned until the number of refusals ofthe 0.005 inch feeler gauge is equal to or greater than thenumber listed under Minimum Installation Refusals inTable 11.5C. If the bolt is tensioned so that no visible gapin any space remains, the bolt and DTI shall be removed,and replaced by a new properly tensioned bolt and DTI.

The feeler gauge shall be refused in all spaces whencoated DTIs (galvanized, painted, or epoxy-coated) areused under the turned element.

11.5.6.4.8 Lock-Pin and Collar Fasteners

The installation of lock-pin and collar fasteners shallbe by methods and procedures approved by the Engineer.

11.5.6.4.9 Inspection

11.5.6.4.9.1 The Engineer shall determine that therequirements of Articles 11.5.6.4.9.2 and 11.5.6.4.9.3, fol-lowing, are met in the work.

11.5.6.4.9.2 Before the installation of fasteners in thework, the Engineer shall check the marking, surface con-

582 HIGHWAY BRIDGES 11.5.6.4.7a

TABLE 11.5C


dition and storage of bolts, nuts, washers, and DTIs, if used,and the faying surfaces of joints for compliance with therequirements of Articles 11.3.2, 11.5.6.1, and 11.5.6.4.1.

The Engineer shall observe calibration and/or test-ing procedures required in Articles 11.5.6.4.4 through11.5.6.4.7 as applicable, to confirm that the selected pro-cedure is properly used and that, when so used with thefastener assemblies supplied, the tensions specified inTable 11.5A are developed.

The Engineer shall monitor the installation of fasten-ers in the work to assure that the selected installationmethod, as demonstrated in the initial testing to developthe specified tension, is routinely followed.

11.5.6.4.9.3 Either the Engineer or the Contractor, inthe presence of the Engineer at the Engineer’s option,shall inspect the tensioned bolts using an inspectiontorque wrench, unless alternate fasteners or direct tensionindicator devices are used, allowing verification by othermethods. Inspection tests should be conducted in a timelymanner prior to possible loss of lubrication or before cor-rosion influences torque.

Three fastener assembly lots in the same condition asthose under inspection shall be placed individually in adevice calibrated to measure bolt tension. This calibrationoperation shall be done at least once each inspection day.There shall be a washer under the turned element in ten-sioning each bolt if washers are used on the structure. Ifwashers are not used on the structure, the material used inthe tension measuring device which abuts the part turnedshall be of the same specification as that used on the struc-ture. In the calibrated device, each bolt shall be tensionedby any convenient means to the specified tension. The in-specting wrench shall then be applied to the tensioned boltto determine the torque required to turn the nut or head 5° (approximately 1 inch at a 12-inch radius) in the tensioning direction. The average of the torque required forall three bolts shall be taken as the job-inspection torque.

Ten percent (at least two) of the tensioned bolts on thestructure represented by the test bolts shall be selected atrandom in each connection. The job-inspection torqueshall then be applied to each with the inspecting wrenchturned in the tensioning direction. If this torque turns nobolt head or nut, the bolts in the connection will be con-sidered to be properly tensioned. But if the torque turnsone or more bolt heads or nuts, the job-inspection torqueshall then be applied to all bolts in the connection. Anybolt whose head or nut turns at this stage shall be reten-sioned and reinspected. The Contractor may, however,retension all the bolts in the connection and resubmit it forinspection, so long as DTIs are not overtensioned or fas-tener assemblies are not damaged.

11.5.7 Welding

Welding, welder qualifications, prequalification ofweld details and inspection of welds shall conform to therequirements of the current ANSI/AASHTO/AWS D1.5Bridge Welding Code.

Brackets, clips, shipping devices, or other material notrequired by the plans or special provisions shall not bewelded or tacked to any member unless shown on theshop drawings and approved by the Engineer.

11.6 ERECTION

11.6.1 General

The Contractor shall provide all tools, machinery, andequipment necessary to erect the structure.

Falsework and forms shall be in accordance with therequirements of Section 3, “Temporary Works.”

11.6.2 Handling and Storing Materials

Material to be stored at the job site shall be placed onskids above the ground. It shall be kept clean and properlydrained. Girders and beams shall be placed upright andshored. Long members, such as columns and chords, shallbe supported on skids placed near enough together to pre-vent injury from deflection. If the contract is for erectiononly, the Contractor shall check the material turned overto him or her against the shipping lists and reportpromptly in writing any shortage or injury discovered.The Contractor shall be responsible for the loss of any ma-terial while in his or her care, or for any damage caused toit after being received by the Contractor.

11.6.3 Bearings and Anchorages

Bridge bearings shall be furnished and installed in con-formance with Section 18, “Bearing Devices,” of theseSpecifications.

If the steel superstructure is to be placed on a sub-structure that was built under a separate contract, the Con-tractor shall verify that the masonry has been constructedin the right location and to the correct lines and elevationsbefore ordering materials.

11.6.4 Erection Procedure

11.6.4.1 Conformance to Drawings

The erection procedure shall conform to the erectiondrawings submitted in accordance with Article 11.2.2.Any modifications to or deviations from this erection pro-cedure will require revised drawings and verification ofstresses and geometry.

11.5.6.4.9.2 DIVISION II—CONSTRUCTION 583


11.6.4.2 Erection Stresses

Any erection stresses, induced in the structure as a re-sult of using a method of erection which differs from theplans, shall be accounted for by the Contractor. The Con-tractor, at his own expense, shall prepare erection designcalculations for such changed methods and submit themto the Engineer. The calculations shall indicate anychange in stresses or change in behavior for the temporaryand final structures. Additional material required to keepboth the temporary and final stresses within the allowablelimits used in design shall be provided at the Contractor’sexpense.

The Contractor will be responsible for providing tem-porary bracing or stiffening devices to accommodate han-dling stresses in individual members or segments of thestructure during erection.

11.6.4.3 Maintaining Alignment and Camber

During erection, the Contractor will be responsible forsupporting segments of the structure in a manner that willproduce the proper alignment and camber in the com-pleted structure. Cross frames and diagonal bracing shallbe installed as necessary during the erection process toprovide stability and assure correct geometry. Temporarybracing, if necessary at any stage of erection, shall be pro-vided by the Contractor.

11.6.5 Field Assembly

The parts shall be accurately assembled as shown onthe plans or erection drawings, and any match-marks shallbe followed. The material shall be carefully handled sothat no parts will be bent, broken, or otherwise damaged.Hammering which will injure or distort the members shallnot be done. Bearing surfaces and surfaces to be in per-manent contact shall be cleaned before the members areassembled. Splices and field connections shall have one-half of the holes filled with bolts and cylindrical erectionpins (half bolts and half pins) before installing and tight-ening the balance of high-strength bolts. Splices and con-nections carrying traffic during erection shall have three-fourths of the holes so filled.

Fitting-up bolts may be the same high-strength boltsused in the installation. If other fitting-up bolts are usedthey shall be of the same nominal diameter as the high-strength bolts, and cylindrical erection pins shall be 1⁄ 32

inch larger.

11.6.6 Pin Connections

Pilot and driving nuts shall be used in driving pins.They shall be furnished by the Contractor without charge.

Pins shall be so driven that the members will take fullbearing on them. Pin nuts shall be screwed up tight andthe threads burred at the face of the nut with a pointedtool.

11.6.7 Misfits

The correction of minor misfits involving minoramounts of reaming, cutting, grinding and chipping will be considered a legitimate part of the erection. How-ever, any error in the shop fabrication or deformation re-sulting from handling and transporting will be cause forrejection.

The Contractor shall be responsible for all misfits, er-rors, and damage and shall make the necessary correctionsand replacements.



Pay quantities for each type of steel and iron will bemeasured by the pound computed from dimensionsshown on the plans using the following rules and as-sumptions:

The weights of rolled shapes shall be computed on thebasis of their nominal weights per foot as shown on thedrawings, or listed in the handbooks.

The weights of plates shall be computed on the basis ofthe nominal weight for their width and thickness as shownon the drawings, plus an estimated overrun computed asone-half the “Permissible Variation in Thickness andWeight” as tabulated in Specification, “General Require-ments for Delivery of Rolled Steel Plates, Shapes, SteelPiling, and Bars for Structural Use,” AASHTO M 160(ASTM A 6).

The weight of castings shall be computed from the di-mensions shown on the approved shop drawings, deduct-ing for open holes. To this weight shall be added 5% allowance for fillets and overrun. Scale weights may besubstituted for computed weights in the case of castingsor of small complex parts for which accurate computa-tions of weight would be difficult.

The weight of temporary erection bolts, shop and field paint, boxes, crates, and other containers used forshipping, and materials used for supporting members dur-ing transportation and erection, will not be included.



The weight of any additional material required by Ar-ticle 11.6.4.2 to accommodate erection stresses resultingfrom the Contractor’s choice of erection methods will notbe included.

In computing pay weight on the basis of computed netweight the following stipulations in addition to those inthe foregoing paragraphs shall apply.

(a) The weight shall be computed on the basis of the net finished dimensions of the parts as shown on the approved shop drawings, deducting for copes,cuts, clips, and all open holes, except bolt holes.(b) The weight of heads, nuts, single washers, andthreaded stick-through of all high tensile strength bolts,both shop and field, shall be included on the basis ofthe following weights:

(c) The weight of fillet welds shall be as follows:

(d) To determine the pay quantities of galvanizedmetal, the weight to be added to the calculated weight

of base metal for the galvanizing will be determinedfrom the weights of zinc coatings specified byAASHTO M 111 (ASTM A 123).(e) No allowance will be made for the weight of paint.

11.7.2 Basis of Payment

The contract price for fabrication and erection of structural steel shall be considered to be full com-pensation for the cost of all labor, equipment, mate-rials, transportation, and shop and field painting, if not otherwise provided for, necessary for the propercompletion of the work in accordance with the con-tract. The contract price for fabrication without erec-tion shall be considered to be full compensation for the cost of all labor, equipment, and materials neces-sary for the proper completion of the work, other than erec-tion and field assembly, in accordance with the contract.

Under contracts containing an item for structural steel,all metal parts other than metal reinforcement for con-crete, such as anchor bolts and nuts, shoes, rockers,rollers, bearing and slab plates, pins and nuts, expansiondams, roadway drains and scuppers, weld metal, bolts em-bedded in concrete, cradles and brackets, railing, and rail-ing pots shall be paid for as structural steel unless other-wise stipulated.

Payment will be made on a pound-price or a lump-sum basis as required by the terms of the contract, but un-less stipulated otherwise, it shall be on a pound-price basis.

For members comprising both carbon steel and other special steel or material, when separate unit pricesare provided for same, the weight of each class of steel ineach such member shall be separately computed, and paidfor at the contract unit price therefore.

Full-size members which are tested in accordancewith the specifications, when such tests are required bythe contract, shall be paid for at the same rate as for com-parable members for the structure. The cost of testing in-cluding equipment, labor and incidentals shall be in-cluded in the contract price for structural steel. Memberswhich fail to meet the contract requirements, and mem-bers rejected as a result of tests, will not be paid for bythe Department.



Section 12STEEL GRID FLOORING

12.1 GENERAL

12.1.1 Description

This work shall consist of furnishing and installingsteel grid flooring of the open type, or of the concretefilled type as specified in the special provisions and asshown on the plans. When the Contractor is allowed to se-lect any details of the design, said details shall meet therequirements for the design of steel grid floors in DivisionI, Article 3.27.


The Contractor shall submit complete working draw-ings with assembly details to the Engineer for approval.Fabrication or construction of the flooring shall not bestarted until the drawings have been approved. Such ap-proval shall not relieve the Contractor of any responsibil-ity under the contract for the successful completion of thework.

12.2 MATERIALS

12.2.1 Steel

All steel shapes, plates and bars shall conform toAASHTO M 270 (ASTM A 709) Grade 36, 50, or 50W.Unless the material is galvanized or epoxy coated it shallhave a copper content of 0.2%.


12.2.2 Protective Treatment

Open type floors, unless otherwise specified, shall begalvanized in accordance with the requirements ofAASHTO M 111 (ASTM A 123).

Filled or partially filled types, as called for in the spe-cial provisions, shall be either galvanized, painted, epoxycoated, or supplied in unpainted weathering steel.

If painted, the paint shall be applied according to thespecifications for Section 13, “Painting,” except that dip-ping will be permitted. The paint shall be as specified formetal structures unless paint or coating of another type isrequired by the special provisions. When painting is spec-ified, those areas of steel grid flooring completely encasedin concrete may remain unpainted, unless otherwise spec-ified.

12.2.3 Concrete

All concrete in filled steel grid floors shall conform tothe requirements of Section 8, “Concrete Structures.” Theconcrete and the size of aggregate shall be as specified forClass C (AE) concrete.

12.2.4 Skid Resistance

The upper edges of all members forming the wearingsurface of open type grid flooring shall be serrated to givethe maximum skid resistance.

Concrete filled or overlayed grid floors shall be givena skid-resistant texture as specified in Article 8.10.2.

12.3 ARRANGEMENT OF SECTIONS

Where the main elements are normal to center line ofroadway, the units generally shall be of such length as toextend over the full width of the roadway for roadways upto 40 feet but in every case the units shall extend over atleast three panels. Where joints are required, the ends ofthe main floor members shall be welded at the joints overtheir full cross-sectional area, or otherwise connected toprovide full continuity.

Where the main elements are parallel to center line ofroadway, the sections shall extend over not less than threepanels, and the ends of abutting units shall be weldedover their full cross-sectional area, or otherwise con-nected to provide full continuity in accordance with thedesign.

587


12.4 PROVISION FOR CAMBER

Unless otherwise provided on the plans, provision forcamber shall be made as follows:

Steel units so rigid that they will not readily follow thecamber required shall be cambered in the shop. For gridflooring types other than those employing a field placedfull depth concrete filling attached to the deck withwelded shear connectors, the stringers shall be canted orprovided with shop-welded beveled bearing bars to pro-vide a bearing surface parallel to the crown of the road-way. If beveled bars are used, they shall be continuous andfillet welded along the center line of the stringer flange; inwhich case, the design span length shall be governed bythe width of the bearing bar instead of the width of thestringer flange.

Longitudinal stringers, except as provided in the fol-lowing paragraph, shall be mill cambered or providedwith bearing strips so that the completed floor after deadload deflection will conform to the longitudinal cambershown on the plans.

Vertical adjustment of full-depth-filled grid floors,which are to be connected to supporting members withshear connectors, may be accomplished by use of adjust-ing bolts operating through nuts welded to the grid andbearing on the top flange of framing members. Alterna-tively, shims may be used, and shims must be used if con-struction vehicles are to be allowed on the floor prior tofinal attachment.

12.5 FIELD ASSEMBLY

Areas of considerable size shall be placed and, if nec-essary, adjusted to proper fit before the floor is connectedto its supports. Care shall be taken during lifting and plac-ing to avoid overstressing the grid units. The main ele-ments shall be made continuous as specified in Article12.3, and sections shall be connected together along theiredges by welding or bolting in accordance with the plansor the approved working drawings.

12.6 CONNECTION TO SUPPORTS

Except when other connection methods are specified orapproved, the floor shall be connected to its steel supportsby welding every fourth main element to the supportingmember; however, welds shall be spaced no greater than15 inches on centers. Before any welding is done, the floorshall either be temporarily loaded or it shall be clampeddown to make a tight joint with full bearing. To minimizethe stresses induced through clamping down, any differ-ential elevation of 1⁄ 4 inch or more over a 4-foot support-

ing member shall be shimmed before welding the shim,the grid, and the supporting member. The location, length,and size of the welds shall be subject to the approval ofthe Engineer.

Around the perimeter of continuous units of grid floor-ing, the ends of all the main steel members of the flooringshall be securely fastened together by means of steelplates or angles welded to the ends of the main members,or by thoroughly encasing the ends with concrete.

When specified or approved, methods other than weld-ing may be used for attaching steel grid floors (both openand concrete filled types) to framing members. In suchcases, welded headed shear connectors can be employedfor concrete filled grids and open steel grids can be con-nected to framing members by bolting.

12.7 WELDING

All shop and field welding shall be done in accordancewith ANSI/AASHTO/AWS Bridge Welding Code D1.5.

12.8 REPAIRING DAMAGED GALVANIZEDCOATINGS

Galvanized surfaces that are abraded or damaged atany time after the application of the zinc coating shall berepaired by thoroughly wire brushing the damaged areasand removing all loose and cracked coating, after whichthe cleaned areas shall be painted with two applications ofunthinned commercial quality zinc-rich primer (organicvehicle type). Spray cans shall not be used.

12.9 PLACEMENT OF CONCRETE FILLER

12.9.1 Forms

Concrete filled types of flooring with bottom flangesnot in contact with each other shall be provided with bot-tom forms of metal or wood to retain the concrete fillerwithout excessive leakage. Forms shall be removed afterthe concrete has been cured except that metal forms con-forming to the following paragraph may be left in place.

If metal form strips are used they shall fit tightly on thebottom flanges or protrusions of the grid members and be placed in noncontinuous lengths so as to extend notmore than 1 inch onto the edge of each support, but in allcases the forms shall be such as will result in adequatebearing of slab on the support. If metal forms are to beleft in place, they shall either be galvanized or protectivetreated by the same method that is required for the gridflooring.



12.9.2 Placement

When the plans indicate that the concrete filling doesnot extend to the bottom of the steel grid, the concrete, ex-cept concrete for cells in which shear connectors are to beinstalled, may be placed with the grid in an inverted posi-tion prior to installation, or the portion of the grid to re-main unfilled may be blocked out by the use of a tempo-rary inert filling material, such as sand or polystyreneboard filler which is later removed, or by the use of metallath form strips or other approved methods. The methodused shall permit full embedment of the tertiary bars andthe shear connector studs, if used.

When the plans or specifications indicate that filled orpartially filled grids or reinforced concrete slabs incorpo-rating steel grids are to act compositely with their sup-porting members, all shear connecting studs shall be fullyencased in concrete and the entire area between the topflange of the supporting member and the bottom of thegrid filling shall be filled with concrete.

The concrete for filled grid floors shall be mixed,placed, and cured in accordance with the requirements ofSection 8. The concrete shall be thoroughly compacted byvibrating the steel grid floor. The vibrating device and themanner of operating it shall be subject to the approval ofthe Engineer.


Steel grid flooring will be measured by the square foot.The number of square feet will be based on the dimen-sions of the flooring in place and approved by the Engi-neer in the completed work.

Steel grid flooring will be paid for at the contract priceper square foot. Such payment for steel grid floor, open orconcrete filled types, shall be considered to be full com-pensation for the cost of furnishing of all materials, equip-ment, tools, and labor necessary for the satisfactory com-pletion of the work.



Section 13PAINTING

13.1 GENERAL

13.1.1 Description

This work shall consist of the painting of surfacesshown on the plans or otherwise specified to be painted.The work includes, but is not limited to, the preparationof surfaces to be painted, application and curing of thepaint, protection of the work, protection of existing facil-ities, vehicles and the public from damage due to thiswork, and the furnishing of all labor, equipment, and ma-terials needed to perform the work.

13.1.2 Protection of Public and Property

The Contractor shall comply with all applicable envi-ronmental protection and occupational safety and healthstandards, rules, regulations, and orders. Failure to com-ply with these standards, rules, regulations, and orderswill be sufficient cause for suspension or disqualification.

All reasonable precautions shall be taken to containwaste materials (used blasting material and old paint)classified as hazardous. Disposal of hazardous waste ma-terial shall be performed in accordance with all applicablefederal, state, and local laws.

The Contractor shall provide protective devices suchas tarps, screens or covers as necessary to prevent damageto the work and to other property or persons from allcleaning and painting operations.

Paint or paint stains that result in an unsightly ap-pearance on surfaces not designated to be painted shallbe removed or obliterated by the Contractor at own ex-pense.

13.1.3 Protection of the Work

All painted surfaces that are marred or damaged as aresult of operations of the Contractor shall be repaired bythe Contractor, at own expense, with materials and to acondition equal to that of the coating specified herein.

If traffic causes an objectionable amount of dust, theContractor, when directed by the Engineer, shall sprinkle

the adjacent roadbed and shoulders with water or dust pal-liative for a sufficient distance on each side of the locationwhere painting is being done.

Upon completion of all painting operations and of anyother work that would cause dust, grease, or other foreignmaterials to be deposited on the painted surfaces, thepainted surfaces shall be thoroughly cleaned. At the timeof opening structures to public traffic, the painting shallbe completed, and the surfaces shall be undamaged andclean.

13.1.4 Color

If not otherwise shown or specified, the color of the topor finish coat of paint shall be as directed by the Engineer.

13.2 PAINTING METAL STRUCTURES

13.2.1 Coating Systems and Paints

The coating system and paints to be applied shall con-sist of the system in Table 13.2.1 which is specified for useor modified by the special provisions.

13.2.2 Weather Conditions

Paint shall be applied only on thoroughly dry surfaces.Painting will not be permitted when the atmospheric tem-perature, paint, or the surface to be painted is at or below40°F or above 100°F, or when metal surfaces are less than5°F above the dew point, or when the humidity exceeds85% at the site of the work, or when freshly painted sur-faces may become damaged by rain, fog, or dust, or whenit can be anticipated that the atmospheric temperature willdrop below 40°F during the drying period, except as pro-vided herein for painting in enclosures. Metal surfaceswhich are hot enough to cause the paint to blister, to pro-duce a porous paint film, or to cause the vehicle to sepa-rate from the pigment shall not be painted.

Subject to approval of the Engineer, the Contractormay provide a suitable enclosure to permit painting dur-ing inclement weather. Provisions shall be made to artifi-

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cially control atmospheric conditions inside the enclo-sure within limits suitable for painting throughout thepainting operation. Surfaces painted under cover in dampor cold weather shall remain under cover until the paintdries or weather conditions permit open exposure. Fullcompensation for providing and maintaining such en-closures shall be considered as included in the prices paid for the various contract items of work involvingpainting and no additional compensation will be allowedtherefore.

All blast cleaning, except that performed within closedbuildings, and all painting shall be performed during day-light hours unless otherwise provided by the contract doc-uments.

13.2.3 Surface Preparation

All exposed surfaces of structural steel, except galva-nized or metalized surfaces, shall be cleaned and painted.

All surfaces of new structural steel shall be cleaned bythe blast-cleaning method unless otherwise specified inthe special provisions, or approved in writing by the En-gineer.

In repainting existing steel structures the method ofcleaning shall be as specified in the special provisions.Any damage to sound paint, on areas not designated fortreatment, resulting from the Contractor’s operations shallbe repaired by the Contractor at own expense to the satis-faction of the Engineer.

The methods used in the cleaning of metal surfacesshall conform to the following.

13.2.3.1 Blast Cleaning

Abrasives used for blast cleaning shall be either cleandry sand, mineral grit, steel shot, or steel grit, at the optionof the Contractor, and shall have a suitable grading to pro-duce satisfactory results. The use of other abrasives willnot be permitted unless approved in writing by the Engi-neer.

Unwashed beach sand containing salt or excessiveamounts of silt will not be allowed.

All dirt, mill scale, rust, paint, and other foreign material shall be removed from exposed steel surfaces in accordance with the requirements of the Steel Struc-tures Painting Council Surface Preparation SpecificationNo. 10, SSPC-SP10—Near-White Blast Cleaning. Blastcleaning shall leave all surfaces with a dense and uni-form anchor pattern of not less than 1 nor more than 3mils. as measured with an approved surface profile com-parator.

When blast cleaning is being performed near machin-ery, all journals, bearings, motors, and moving parts shallbe sealed against entry of abrasive dust before blast clean-ing begins.

Blast cleaned surfaces shall be primed or treated thesame day blast cleaning is done, unless otherwise autho-rized by the Engineer. If cleaned surfaces rust or are con-


TABLE 13.2.1


taminated with foreign material before painting is accom-plished, they shall be reblast cleaned by the Contractor atown expense.

13.2.3.2 Steam Cleaning

All dirt, grease, loose chalky paint, or other foreignmaterial which has accumulated on the previously paintedor galvanized surfaces shall be removed with a steamcleaning apparatus which shall precede all other phases ofcleaning. It is not intended that sound paint be removedby this process. Any paint which becomes loose, curled,lifted, or loses its bond with the preceding coat or coatsafter steam cleaning shall be removed as directed by theEngineer to sound paint or metal surface by the Contrac-tor at own expense.

A biodegradable detergent shall be added to the feedwater of the steam generator or applied to the surface to becleaned. The detergent shall be of such composition andshall be added or applied in such quantity that the cleaningas described in the above paragraph is accomplished.

Any residue, detergent, or other foreign material whichmay accumulate on cleaned surfaces shall be removed byflushing with fresh water.

Steam cleaning shall not be performed more than 2weeks prior to painting or other phases of cleaning.

Subsequent painting shall not be performed until thecleaned surfaces are thoroughly dry and in no case in lessthan 24 hours after cleaning and flushing.

13.2.3.3 Solvent Cleaning

Unless otherwise prohibited by the special provisions,solvents shall be used to remove oil, grease, and other sol-uble contaminants in accordance with the requirements ofSSPC-SP1, Solvent Cleaning. Solvent cleaning shall beperformed prior to blast cleaning. If contamination remainsafter blasting, the area shall be recleaned with solvent.

13.2.3.4 Hand Cleaning

Wire brushes, either hand or powered, hand scrapingtools, power grinders, or sandpaper shall be used to re-move all dirt, loose rust and mill scale, or paint which isnot firmly bonded to the metal surfaces.

Pneumatic chipping hammers shall not be used unlessauthorized in writing by the Engineer.

13.2.4 Application of Paints

The Contractor shall notify the Engineer, in writing, atleast 1 week in advance of the date that cleaning andpainting operations are to begin.

Painting shall be done in a neat and workmanlike man-ner. Unless otherwise specified, paint shall be applied bybrush, spray, or roller, or any combination thereof pecu-liar to the paint being applied.

Each application of paint shall be thoroughly cured andany skips, holidays, thin areas, or other deficiencies cor-rected before the succeeding application. The surface ofthe paint being covered shall be free from moisture, dust,grease, or any other deleterious materials that would pre-vent the bond of the succeeding applications. In spotpainting, old paint which lifts after the first applicationshall be removed by scraping and the area repainted be-fore the next application.

Paints specified are formulated ready for applicationand no thinning will be allowed unless otherwise providedin the applicable materials specification for the paintbeing used.

Brushes, when used, shall have sufficient body andlength of bristle to spread the paint in a uniform film.Round, oval-shaped brushes, or flat brushes not widerthan 41⁄2 inches shall be used. Paint shall be evenly spreadand thoroughly brushed out.

On all surfaces that are inaccessible for painting byregular means, the paint shall be applied by sheepskindaubers, bottle brushes, or by any other means approvedby the Engineer.

Rollers, when used, shall be of a type that do not leavea stippled texture in the paint film. Rollers shall be usedonly on flat, even surfaces to produce a paint film of eventhickness with no skips, runs, sags, or thin areas.

Paint may be applied with airless or conventional sprayequipment.

Suitable traps or separators acceptable to the Engineershall be furnished and installed in the airline to each spraypot to exclude oil and water from the air.

Any spray method which produces excessive paintbuild-up, runs, sags, or thin areas in the paint film, or skipsand holidays, will be considered unsatisfactory and theEngineer may require modification of the spray method orprohibit its use and require brushing instead.

Mechanical mixers shall be used to mix paint. Prior toapplication, paint shall be mixed a sufficient length oftime to thoroughly mix the pigment and vehicle together,and shall be kept thoroughly mixed during its application.

The dry film thickness of the paint will be measured inplace with a calibrated magnetic film thickness gage ac-cording to Steel Structures Painting Council SSPC-PA2.

The thickness of each application shall be limited tothat which will result in uniform drying throughout thepaint film.

Succeeding applications of paint shall be of such shadeas to contrast with the paint being covered.



Structures shall be blast cleaned and painted with thetotal thickness of undercoats before erection. After erec-tion and before applying subsequent paint, all areas wherepaint has been damaged or has deteriorated and all ex-posed unpainted surfaces shall be thoroughly cleaned andspot painted with the specified undercoats to the specifiedthickness.

Surfaces exposed to the atmosphere and which wouldbe inaccessible for painting after erection shall be paintedthe full number of applications prior to erection.

Vinyl wash primer, if required, shall not be appliedmore than 12 hours before application of the succeedingcoat of paint. The vinyl wash primer shall be applied byspraying to produce a uniform wet film on the surface.The dry film thickness shall be between 0.3 and 0.5 mils.

The painting of areas under joint connection and spliceplates shall conform to Article 11.5.6.3.

13.2.4.1 Application of Zinc-Rich Primers

Zinc-rich primers, which include organic and inor-ganic zinc primers, shall be applied by spray methods. Onareas inaccessible to spray application, the paint may beapplied by brush or daubers.

Mechanical mixers shall be used in mixing the primer.After mixing, zinc-rich primers shall be strained througha metal 30-60 mesh screen or a double layer of cheese-cloth immediately prior to or during pouring into the spraypot.

An agitating spray pot shall be used in all spray appli-cation of zinc-rich primers. The agitator or stirring rodshall reach to within 2 inches of the bottom of the spraypot and shall be in motion at all times during primer ap-plication. Such motion shall be sufficient to keep theprimer well mixed.

Spray equipment shall provide the proper pot pressureand atomization pressure to produce a coating the com-position of which shall comply in all respects to the spec-ifications for zinc paint. The hose from pot to nozzle shallnot be more than 75 feet long, nor be used more than 15feet above or below the pot.

Cured, zinc-rich primer shall be free from dust, dirt,salt, or other deleterious deposits and thoroughly dry be-fore applying vinyl wash primer.

In addition, the application of inorganic zinc paintsshall conform to the following paragraphs.

Succeeding applications of inorganic zinc paints shallbe applied within 24 hours, but not less than 30 minutesafter prior application of such paint.

In areas where mud-cracking occurs in the inorganiczinc paint, it shall be blast cleaned back to soundly bondedpaint, and recoated to the same thickness by the samemethods specified for the original coat.

Paint shall be cured for 48 hours at a relative humidityof at least 45% before the application of vinyl washprimer. The cured inorganic zinc paint shall be hoseddown with water and be in a surface dry condition beforethe application of vinyl wash primer if the vinyl washprimer is not applied within 3 weeks after the inorganiczinc paint is applied, or when there is evidence of dust,dirt, salt, or other deleterious deposits on the inorganiczinc paint.

13.2.5 Measurement and Payment

Cleaning and painting structural steel will be paid foron the basis of lump sum prices, unless otherwise speci-fied in the special provisions.

The lump sum prices paid for clean structural steel andfor paint structural steel or the lump sum price paid for clean and paint structural steel shall include fullcompensation for furnishing all labor, materials, tools,equipment, and incidentals, and for doing all the workinvolved in cleaning and painting structural steel asshown on the plans, and as specified in these specifica-tions and the special provisions, and as directed by theEngineer.

13.3 PAINTING GALVANIZED SURFACES

All galvanized surfaces that are to be painted shall firstbe cleaned by washing with mineral spirit solvent suffi-cient to remove any oil, grease, or other materials foreignto the galvanized coating.

After cleaning, vinyl wash primer shall be applied to such surfaces. The vinyl wash primer shall be ap-plied by spraying to produce a uniform wet film on the surface. The dry film thickness shall be between 0.3 and0.5 mils.

Finish paint to be applied to primed galvanized sur-faces shall be as shown on the plans or otherwise speci-fied. If not shown or otherwise specified, the finish paintshall be the same as that used on adjacent metal work orshall be as directed by the Engineer.

No separate payment will be made for preparing andpainting galvanized surfaces and full compensation forfurnishing all labor, materials, tools, equipment, andincidentals, and for doing all the work involved in pre-paring and painting galvanized surfaces as shown on the plans, and as specified in these specifications and thespecial provisions, and as directed by the Engineer willbe considered as included in the prices paid for thevarious contract items of work involving the galvanizedsurfaces.



13.4 PAINTING TIMBER

13.4.1 General

Unless otherwise shown on the plans or specified in thespecial provisions, all new timber requiring painting shallbe painted with three applications of paint. The paint usedfor various applications will be as specified in these spec-ifications or as shown on the plans or specified in the spe-cial provisions.

The painting of previously painted surfaces shall be asrequired by the plans and specifications.

13.4.2 Preparation of Surfaces

All cracked or peeled paint, loose chalky paint, dirt andother foreign material shall be removed by wire brushing,scraping or other means immediately prior to painting.The moisture content of the timber shall not be more than20% at the time of the first application.

13.4.3 Paint

Paint for timber structures, except as otherwiseprovided herein, shall conform to the Specification forWhite and Tinted Ready-Mixed Paint, AASHTO M 70.The paint as specified is intended for use in covering pre-viously painted surfaces. When it is applied to unpaintedtimber, turpentine and linseed oil shall be added asrequired by the character of the surface in an amount notto exceed 1 pint per gallon of the paint as specified. Thepaint shall be either white or tinted as directed by theEngineer.

If a black finish paint is specified, the first or prime coatshall be as specified above. Black paint shall conform tothe Specifications for Black Paint, AASHTO M 68.

13.4.4 Application

When permitted in writing by the Engineer, the first ap-plication of paint may be applied prior to erection.

After the first application has dried and the timber is inplace, all cracks, checks, nail holes, or other depressionsshall be puttied flush with the surface and allowed to drybefore the second application of paint.

Paint shall be applied by brush, air spray, or roller,spread evenly, and worked thoroughly into all seasoningcracks, corners, and recesses. No later coat shall be ap-plied until the full thickness of the previous coat has dried.

Final brush strokes with aluminum paint shall be madein the same direction to ensure that powder particles“leaf” evenly.

13.4.5 Painting Treated Timber

Timber treated with creosote or oil-borne, penta-chlorophenol preservatives shall normally not be painted.

Timber treated with water-borne preservatives shall beclean and be reduced to no more than 20% moisture con-tent before it is painted. Any visible salt crystals on thewood surface shall be washed and brushed away, and themoisture content reduced again to the specified level be-fore painting. Stored timber awaiting painting shall becovered and stacked with spreaders to ensure air circula-tion.

13.4.6 Payment

No separate payment will be made for preparing sur-faces and for painting new timber. The painting of exist-ing timber will be paid for on the basis of lump sumprices. Full compensation for furnishing all labor, materi-als, tools, equipment, and incidentals, and for doing all thework involved in preparing surfaces and painting timberas shown on the plans, and as specified in these specifica-tions and the special provisions, and as directed by the En-gineer will be considered as included in the prices paid forthe various contract items of work involving new timberor the prices paid for painting existing timber.

13.5 PAINTING CONCRETE


Prior to painting concrete surfaces, laitance and curingcompounds shall be removed from the surface by abrasiveblast cleaning in accordance with Article 13.2.3.1.

Concrete surfaces shall be thoroughly dry and free ofdust at the time the paint is to be applied.

Any artificial drying procedures and methods shall besubject to approval by the Engineer.

13.5.2 Paint

Unless otherwise specified in the special provisions,paint to be applied to concrete surfaces shall be acrylicemulsion and shall comply in all respects to Federal Spec-ification TT-P-19 (latest revision), Paint, Acrylic Emul-sion, Exterior. This paint may be tinted by using “univer-sal” or “all purpose” concentrates.

13.5.3 Application

Acrylic emulsion paint shall be applied in not less thantwo applications to produce a uniform appearance.



The paint shall be applied only when the ambient tem-perature is 50°F, or above. Painting will not be permittedwhen it can be anticipated that the ambient temperaturewill drop below 50°F during the application and drying ofthe paint.


Preparing and painting concrete will be measured ei-ther by the lump sum or by the square foot as listed in the

schedule of bid items. When measured by the square foot,measurement will be determined along the surface of theactual area painted.

The contract price paid per lump sum or square foot forprepare-and-paint concrete shall include full compensationfor furnishing all labor, materials, tools, equipment, and in-cidentals, and for doing all the work involved in preparingthe concrete and applying the paint to concrete surfaces, asshown on the plans, and as specified in these specificationsand the special provisions, and as directed by the Engineer.



Section 14STONE MASONRY

14.1 DESCRIPTION

This work shall consist of the construction of stone ma-sonry structures and the stone masonry portions of com-posite structures in accordance with these Specificationsand in reasonably close conformity with the lines andgrades shown on the plans or established by the Engineer.

14.1.1 Rubble Masonry

Rubble masonry, as here specified, shall include vari-ous classes of roughly squared and dressed stone laid incement mortar.

14.1.2 Ashlar Masonry

Ashlar masonry shall consist of first-class cut stone masonry laid in regular courses and shall includeall work in which, as distinguished from rubble masonry,the individual stones are dressed or tooled to exact di-mensions.

14.2 MATERIALS

14.2.1 Stone for masonry shall be tough, dense, soundand durable and free of seams, cracks, inclusions or otherstructural defects. Stone shall be of the type and qualityshown on the plans or otherwise specified. Prior to ship-ment of stone to the job site, the Contractor shall obtainapproval of the proposed source and shall submit a repre-sentative sample of stone to the Engineer for inspectionand, if necessary, testing. The sample shall be dressed andfinished as specified for use in the work and shall not beless than 6 inches in any dimension. All stone used in thework shall be of a quality comparable to that of the sam-ple submitted.

14.2.1.1 Rubble Stone

Stone for mortar rubble masonry shall be free fromrounded, worn, or weathered surfaces. All weatheredstone shall be rejected.

14.2.1.2 Ashlar Stone

Stone for ashlar masonry shall be reasonably finegrained and uniform in color. Preferably, stone shall befrom a quarry, the product of which is known to be of sat-isfactory quality. Stone shall be of such character that itcan be brought to such lines and surfaces, whether curvedor plane, as may be required. Any stone having defectsthat have been repaired with cement or other materialsshall be rejected.

14.2.2 Shipment and Storage of Stone

Quarry operations and delivery of stone to the point ofuse shall be organized to insure deliveries well ahead ofmasonry operations. A sufficiently large stock of the spec-ified stone shall be kept on the site at all times, to permitadequate selection of stone by the masons.

The stone shall be kept free from dirt, oil, or any otherinjurious material which may prevent the proper adhesionof the mortar or detract from the appearance of the ex-posed surfaces.

14.2.3 Mortar

The ingredients used in making mortar shall conformto the following requirements:

Portland Cement, Admixtures and Water; Section 8Masonry Cement; ASTM C 91Hydrated Lime; ASTM C 207Quick Lime used to make lime putty; ASTM C 5Sand Aggregate; AASHTO M 45 (ASTM C 144)

The proportions of materials shall be such that thevolume of sand in a damp, loose condition is between 21⁄4 and 3 times the volume of the cementitious materials.The cementitious materials shall consist of either one part of portland cement to between 1⁄ 4 and 1⁄ 2 parts ofhydrated lime or lime putty, or one part of portland cementto between one and two parts of masonry cement.Premixed materials conforming to these requirementsmay be used.

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Admixtures shall be used only when specified or ap-proved by the Engineer.

14.3 MANUFACTURE OF STONE FORMASONRY

14.3.1 General

Each stone shall be free from depressions and projec-tions that might weaken it or prevent it from being prop-erly bedded, and shall be of a shape to meet the require-ments for the class of masonry specified.

When no dimensions are shown on the plans, thestones shall be furnished in the sizes and face areas nec-essary to produce the general characteristics and appear-ance as indicated on the plans.

The thickness of courses, if varied, shall diminish reg-ularly from bottom to top of wall. The size of ring stonesin arches shall be as shown on the plans.

When headers are required, their lengths shall be notless than the width of bed of the widest adjacent stretcherplus 12 inches.

14.3.2 Surface Finishes of Stone

For the purpose of this specification the surface fin-ishes of stone are defined as follows:

Smooth-finished: Having a surface in which the varia-tions from the pitch line do not exceed 1⁄ 16 inch.Fine-finished: Having a surface in which the varia-tions from the pitch line do not exceed 1⁄ 4 inch.Rough-finished: Having a surface in which the varia-tions from the pitch line do not exceed 1⁄ 2 inch.Scabbled: Having a surface in which the variationsfrom the pitch line do not exceed 3⁄ 4 inch.Rock-faced: Having an irregular projecting face without indications of tool marks. The projectionsbeyond the pitch line shall not exceed 3 inches andno part of the face shall recede back of the pitch line.

14.3.3 Rubble Masonry

14.3.3.1 Size

Individual stones shall have a thickness of not less than8 inches and a width of not less than 11⁄2 times the thick-ness. No stones, except headers, shall have a length lessthan 11⁄2 times their width.

14.3.3.2 Shape

The stones shall be roughly squared on joints, beds,and faces. Selected stone, roughly squared and pitched to

line, shall be used at all angles and ends of walls. If spec-ified, all corners or angles in exterior surfaces shall be fin-ished with a chisel draft.

Bed surfaces of face stones shall be normal to the facesof the stones for about 3 inches and from this point maydepart from normal not more than 2 inches in 12 inches.Joint surfaces of face stones shall form an angle with thebed surfaces of not less than 45°.

All shaping or dressing of stone shall be done beforethe stone is laid in the wall, and no dressing or hammer-ing which will loosen the stone will be permitted after itis placed.

14.3.3.3 Dressing

Stone shall be dressed to remove any thin or weak por-tions. Face stones shall be dressed to provide bed and jointlines with a maximum variation from true line of 11⁄ 2

inches unless otherwise indicated on the plans or in thespecial provisions.

14.3.4 Ashlar Masonry

14.3.4.1 Size

The individual stones shall be large and well propor-tioned. They shall not be less than 12 inches nor more than30 inches in thickness.

14.3.4.2 Dressing

Stones shall be dressed to exact sizes and shapesbefore being laid and shall be cut to lie on their naturalbeds with top and bottom truly parallel. Hollow beds will not be permitted. The bottom bed shall be the fullsize of the stone and no stone shall have an over-hangingtop. In rock-face construction the face side of any stoneshall not present an undercut contour adjacent to its bottom arris giving a top-heavy, unstable appearancewhen laid.

Beds of face stone shall be fine-finished for a depth ofnot less than 12 inches.

Vertical joints of face stone shall be fine-finished andfull to the square for a depth of not less than 9 inches.

Exposed surfaces of the face stone shall be given thesurface finish indicated on the plans, with edges pitchedto true lines and exact batter. Chisel drafts 11⁄ 2 inches wideshall be cut at all exterior corners. Face stone forming thestarling or nosing of piers shall be rough-finished unlessotherwise specified.

Holes for stone hooks shall not be permitted to show inexposed surfaces.



14.3.4.3 Stretchers

Stretchers shall have a width of bed of not less than 11⁄2

times their thickness. They shall have a length of bed notless than twice nor more than 31⁄ 2 times their thickness,and not less than 3 feet.

14.3.5 Arch Ring Stones

Arch ring stone joint surfaces shall be radial and atright angles to the front faces of the stones. They shall bedressed for a distance of at least 3 inches from the frontfaces and the soffits, from which points they may departfrom a plane normal to the face not to exceed 3⁄ 4 inches to12 inches. The back surface in contact with the concreteof the arch barrel shall be parallel to the front face andshall be dressed for a distance of 6 inches from the intra-dos. The top shall be cut perpendicular to the front faceand shall be dressed for a distance of at least 3 inches fromthe front.

When concrete is to be placed after the masonry hasbeen constructed, adjacent ring stones shall vary at least 6inches in depth.

Stratification in arch ring stones shall be parallel to theradial joints and in other stones shall be parallel to the beds.

When specified in the special provisions, a full-sizedtemplate of the arch ring shall be laid out near the quarrysite, showing face dimensions of each ring stone andthickness of joints. The template shall be approved by theEngineer before the shaping of any ring stone is started,and no ring stone shall be placed in the structure until allring stones have been shaped, dressed, and approved bythe Engineer.

14.4 CONSTRUCTION


Stone masonry shall not be constructed in freezingweather or when the stone contains frost, except by writ-ten permission of the Engineer and subject to such condi-tions as he or she may require.

14.4.2 Mixing Mortar

The mortar shall be hand or machine mixed, as may berequired by the Engineer. In the preparation of hand-mixed mortar, the sand and cement shall be thoroughlymixed together in a clean, tight mortar box until the mix-ture is of uniform color, after which clean water shall beadded in such quantity as to form a stiff plastic mass. Ma-

chine-mixed mortar shall be prepared in an approvedmixer and shall be mixed not less than 3 minutes nor morethan 10 minutes. Mortar shall be used within 11⁄ 2 hoursafter mixing and before final set begins. Retempering ofmortar shall be done as necessary to maintain proper con-sistency during placement.

14.4.3 Selection and Placing of Stone

14.4.3.1 General

When masonry is placed on a prepared foundation bed,the bed shall be firm and normal to, or in steps normal to,the face of the wall, and approved by the Engineer beforeany stone is placed. When it is placed on foundation ma-sonry, the bearing surface of the foundation masonry shallbe cleaned thoroughly and in a saturated-surface dry con-dition when the mortar bed is spread.

All masonry shall be constructed by experienced work-men. Face stones shall be set in random bond to producethe effect shown on the plans.

Care shall be taken to prevent the bunching of smallstones or stones of the same size. When weathered or col-ored stones, or stones of varying texture, are being used,care shall be exercised to distribute the various kinds ofstones uniformly throughout the exposed faces of thework. Large stones shall be used for the bottom coursesand large, selected stones shall be used in the corners. Ingeneral, the stones shall decrease in size from the bottomto the top of work.

Each stone shall be cleaned and thoroughly saturatedwith water before being set and the bed which is to receiveit shall be clean and well moistened. All stones shall bewell bedded in freshly made mortar. The mortar jointsshall be full and the stones carefully settled in place be-fore the mortar has set. No spalls will be permitted in thebeds. No pinning up of stones with spalls will be permit-ted in beds.

Stone shall not be dropped upon, or slid over the wall,nor will hammering, rolling, or turning of stones on thewall be allowed. They shall be carefully set without jarringthe stone already laid and they shall be handled with alewis or other appliance that will not cause disfigurement.

In case any stone is moved or the joint broken, thestone shall be taken up, the mortar thoroughly cleanedfrom bed and joints, and the stone reset in fresh mortar.

14.4.3.2 Rubble Masonry

Rubble masonry shall be laid to line and in coursesroughly leveled up. The bottom or foundation coursesshall be composed of large, selected stones and all coursesshall be laid with bearing beds parallel to the natural bed



of the material. The vertical joints in each course of rub-ble masonry shall break with those in adjoining courses atleast 6 inches. In no case shall a vertical joint be so locatedas to occur directly above or below a header.

14.4.3.3 Ashlar Masonry

The stones in any one course of ashlar masonry shall be placed so as to form bonds of not less than 12inches with the stones of adjoining courses. Headers shallbe placed over stretchers and, in general, the headers ofeach course shall equally divide the spaces between theheaders of adjoining courses, but no header shall beplaced over a joint and no joint shall be made over aheader.

14.4.4 Beds and Joints

Beds and joints in rubble masonry shall have an aver-age thickness of not more than 1 inch. Beds and joints inashlar masonry shall be not less than 3⁄ 8 inch nor more than1⁄2 inch in thickness and the thickness of the joint or bedshall be uniform throughout.

The thickness of beds in ashlar masonry may vary asshown from the bottom to the top of the work. However,in each course the beds shall be of uniform thicknessthroughout.

Beds shall not extend in an unbroken line through morethan five stones.

Joints in ashlar masonry shall be vertical. In all othermasonry, joints may be at angles with the vertical from 0°to 45°.

Each face stone shall bond with all contiguous facestones at least 6 inches longitudinally and 2 inches verti-cally. Ring stone joints on the faces and soffits shall be notless than 1⁄ 4 inch nor more than 11⁄2 inches in thickness.

Cross beds for vertical walls shall be level and for bat-tered walls may vary from level to normal to the batterline of the face of the wall. All joints shall be completelyfilled with mortar.

14.4.5 Headers

Headers shall hold in the heart of the wall the same sizeshown in the face and shall extend not less than 12 inchesinto the core or backing. They shall occupy not less thanone-fifth of the face area of the wall and shall be evenlydistributed.

Headers in rubble masonry walls 2 feet or less in thick-ness shall extend entirely through the wall.

Headers in ashlar masonry shall be placed in eachcourse and shall have a width of not less than 11⁄ 2 timestheir thickness. In walls having a thickness of 4 feet or

less, the headers shall extend entirely through the wall. Inwalls of greater thickness, the length of headers shall benot less than 21⁄2 times their thickness when the course is18 inches or less in height, and not less than 4 feet incourses of greater height. Headers shall be spaced not fur-ther apart than 8 feet center to center. There shall be atleast one header to every two stretchers.

14.4.6 Cores and Backing

14.4.6.1 General

Cores and backing shall consist either of roughly bed-ded and jointed headers and stretchers, as specified above,or of Class B or C concrete, as may be specified.

The headers and stretchers in walls having a thicknessof 3 feet or less shall have a width or length equal to thefull thickness of the wall. No backing will be allowed.

14.4.6.2 Stone

When stone is used for cores or backing, at least one-half of the stone shall be of the same size and character asthe face stone, and with parallel ends. No course shall beless than 8 inches thick.

Stone backing shall be laid in the same manner as spec-ified above for face stone, with headers interlocking withface headers when the thickness of the wall will permit.Backing shall be laid to break joints with the face stone.Stone cores shall be laid in full mortar beds so as to bondnot less than 12 inches with face and backing stone andwith each other. Bed joints in cores and backing shall notexceed 1 inch and vertical joints shall not exceed 4 inchesin thickness.

14.4.6.3 Concrete

Concrete used for cores and backing shall conform to the requirements specified in Section 8, “ConcreteStructures.”

The operations involved in the handling and placing ofconcrete used in cores and backing shall conform to therequirements specified in Section 8. However, the pud-dling and compacting of concrete adjacent to the ashlarmasonry facing shall be done in a manner that will insurethe filling of all spaces around the stones and secure fullcontact and efficient bond with all stone surfaces.

14.4.6.4 Leveling Courses

Stone cores and backing shall be carried up to the ap-proximate level of the face course before the succeedingcourse is started.



The construction joints produced in concrete cores orbacking by the intermittent placing of concrete shall be lo-cated, in general, not less than 6 inches below the top bedof any course of masonry.

14.4.7 Facing for Concrete

Unless otherwise specified in the Special Provisions,the stone masonry shall be constructed before placingconcrete.

Steel anchors as shown on the plans or specified in theSpecial Provisions shall be used. To improve the bond be-tween the stone masonry and the concrete backing, theback of the masonry shall be made as uneven as the stoneswill permit.

After the stone facing has been laid and the mortar hasattained sufficient strength, all surfaces against whichconcrete is to be placed shall be cleaned carefully and alldirt, loose material, and accumulations of mortar drop-pings removed.

When placing concrete all interstices of the masonryshall be filled and the concrete thoroughly spaded andworked until it is brought into intimate contact with everypart of the back of the masonry.

14.4.8 Copings

14.4.8.1 Stone

Stones for copings of wall, pier, and abutment bridgeseats shall be carefully selected and fully dimensionedstones. On piers, not more than two stones shall be usedto make up the entire width of coping. The copings ofabutment bridge seats shall be of sufficient width to ex-tend at least 4 inches under the backwall. Each step form-ing the coping of a wingwall shall be formed by a singlestone which shall overlap the stone forming the step im-mediately below it at least 12 inches.

Tops of copings shall be given a bevel cut at least 2inches wide, and beds, bevel cuts, and tops shall be fine-finished. The vertical joints shall be smooth-finished andthe copings shall be laid with joints not more than 1⁄ 4 inchin thickness. The undersides of projecting copings, prefer-ably, shall have a drip bead.

Joints in copings shall be located so as to provide notless than a 12-inch bond with the stones of the undercourse and so that no joint will come directly under the su-perstructure masonry plates.

14.4.8.2 Concrete

Copings, bridge seats, and backwalls shall be of thematerial shown on the plans and when not otherwise spec-

ified shall be of Class A concrete which shall conform tothe requirements of Section 8, “Concrete Structures.”

Concrete copings shall be made in sections extendingthe full width of the wall, not less than 12 inches in thick-ness, and from 5 to 10 feet long. The sections may be castin place or precast and set in place in full mortar beds.

14.4.9 Dowels and Cramps

Where required, coping stone, stone in the wings ofabutments, and stone in piers shall be secured withwrought-iron cramps or dowels as indicated on the plans.

Dowel holes shall be drilled through each stone beforethe stone is placed and, after it is in place, such dowelholes shall be extended by drilling into the underlyingcourse not less than 6 inches.

Cramps shall be of the shapes and dimensions shownon the plans or approved by the Engineer. They shall beinset in the stone so as to be flush with the surfaces.

Cramps and dowels shall be set in lead, care beingtaken to completely fill the surrounding spaces with themolten metal, or shall be rigidly anchored by other meansapproved by the Engineer.

14.4.10 Weep Holes

All walls and abutments shall be provided with weepholes. Unless otherwise shown on the plans or directed bythe Engineer, the weep holes shall be placed at the lowestpoints where free outlets can be obtained and shall bespaced not more than 10 feet center to center. A minimumof 2 cubic feet of permeable material encapsulated withfilter fabric shall be placed at each weep hole.

14.4.11 Pointing

Pointing shall not be done in freezing weather or whenthe stone contains frost.

Whenever possible the face joints shall be properlypointed before the mortar becomes set. Joints which can-not be so pointed shall be prepared for pointing by rakingthem out to a depth of 2 inches before the mortar has set.The face surfaces of stones shall not be smeared with themortar forced out of the joints or that used in pointing.

Joints not pointed at the time the stone is laid shall bethoroughly wet with clean water and filled with mortar.The mortar shall conform to Article 14.2.3 except that theproportion of hydrated lime putty shall be increased to 1⁄ 2

to 2 times the volume of the cement or the cement shall beall masonry type cement. The mortar shall be well driveninto the joints and finished with an approved pointing tool.The wall shall be kept wet while pointing is being doneand in hot or dry weather the pointed masonry shall be



protected from the sun and kept wet for a period of at least3 days after completion.

After the pointing is completed and the mortar set, thewall shall be thoroughly cleaned and left in a neat andworkmanlike condition.

14.4.12 Arches

The number of courses and the depth of voussoirsshall be as shown on the plans. Voussoirs shall be placedin the order indicated, shall be full size throughout, andshall have bond not less than their thickness of the stone.Beds shall be roughly pointed to bring them to radialplanes. Radial joints shall be in planes parallel to thetransverse axis of the arch and, when measured at the in-trados, shall not exceed 3⁄ 4 inch in thickness. Jointsperpendicular to the arch axis shall not exceed 1 inch in thickness when measured at the intrados. The intradosface shall be dressed sufficiently to permit the stone to rest properly upon the centering. Exposed faces of the arch ring shall be rock-faced with edges pitched totrue lines.

The work shall be carried up symmetrically about thecrown, the stone being laid in full mortar beds, and thejoints grouted where necessary. Pinning by the use ofstone spalls will not be permitted.

Backing may consist of Class B concrete or of largestones shaped to fit the arch, bonded to the spandrels, andlaid in full beds of mortar. The extrados and interior facesof the spandrel walls shall be given a finished coat of 1:21⁄2 cement mortar which shall be trowelled smooth to re-ceive the waterproofing.

Arch centering, waterproofing, draining, and fillingshall be as specified in Section 3, “Temporary Works,”Section 8, “Concrete Structures,” and Section 21, “Water-proofing.”


Stone masonry will be measured by either the cubicyard or the square yard as listed in the schedule of biditems. The volume or area will be that actually placed tothe limiting dimensions shown on the plans, or the plandimensions as may have been revised by the Engineer.

Stone masonry, as measured above, will be paid for bythe contract price per cubic yard or square foot. Such pay-ment shall be considered to be full compensation for thecost of all labor, tools, materials, and other items inciden-tal to the satisfactory completion of the work.

Concrete used in connection with stone masonry shallbe measured and paid for in the same manner as concretefor structures.



Section 15CONCRETE BLOCK AND BRICK MASONRY

15.1 DESCRIPTION

Concrete block and brick masonry shall consist of con-crete blocks or brick laid in cement mortar and may be un-reinforced or reinforced with steel reinforcing. Block orbrick pavements are not included under this designation.

15.2 MATERIALS

15.2.1 Concrete Block

Unless otherwise specified in the special provisions orapproved in writing by the Engineer, all concrete block formasonry construction shall be Type I moisture controlledunits (Grade N-I) that meet the requirements of ASTM C90. The value of f�m shall be as shown on the plans or asspecified in the special provisions.

Concrete block units should be protected from rain,snow, or other moisture during storage on or off the jobsite to assure that they will meet the Type I moisture re-quirements at the time they are placed in the construction.

15.2.2 Brick

Brick for masonry construction shall conform to theSpecification for Building Brick (solid masonry unitsmade from clay or shale) AASHTO M 114 (ASTM C 62),Concrete Building Brick (ASTM 55), or Solid Load-Bear-ing Concrete Masonry Units (ASTM 145). The type andgrade of brick to be furnished shall be as shown on theplans or as specified in the special provisions.

The bricks shall have a fine-grained uniform, anddense structure, free from lumps of lime, laminations,cracks, checks, soluble salts, or other defects which mayin any way impair their strength, durability, appearance,or usefulness for the purpose intended. Bricks shall emita clear, metallic ring when struck with a hammer.


Reinforcing steel used in the construction of concreteblock or brick masonry structures shall conform to the re-

quirements for uncoated reinforcing in Section 9, “Rein-forcing Steel.”

15.2.4 Mortar

Mortar used shall conform, as regards materials, pro-portions and mixing, to the mortar specified in Articles14.2.3 and 14.4.2.

15.2.5 Grout

Grout for filling voids in hollow masonry units shall ei-ther conform to the requirements of ASTM C 476 or to therequirements of the following paragraph.

As an alternative to the requirements of ASTM C 476,the materials for grout shall conform to the requirementsof Section 8, “Concrete Structures,” for cement, aggre-gates, water and admixtures and to the requirements of Ar-ticle 14.2.3 for lime. Coarse aggregate shall be of either 1⁄2-inch or 3⁄ 8-inch maximum gradation. For fine grout, ifproportioned by volume, the cementitious materials shallconsist of one part Portland cement to no more than 1⁄10 parthydrated lime or lime putty and the aggregates shall con-sist of sand in the amount of 21⁄4 to 3 times the total volumeof cementitious materials. For coarse grout, the propor-tions shall be the same as for fine grout except that coarseaggregate in the amount of 1 to 2 times the total volume ofcementitious materials shall be added. If proportioned byweight, the weights used shall be equivalent to those whichwould be obtained by volumetric methods.

Adjustments in mix proportions, within the limits al-lowed, shall be made as necessary to satisfy workabilityand strength requirements.

Admixtures shall be used only when specified or ap-proved by the Engineer.

15.2.6 Sampling and Testing

15.2.6.1 Mortar

Unless otherwise specified in the special provisions,mortar shall have a minimum 28-day compressive

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strength of 1,800 psi based on the average of three spec-imens tested in accordance with the requirements ofASTM C 780. Field samples shall be obtained as follows:

(a) Spread 1⁄ 2 inch or the thickness of the mortar jointof mortar on masonry units.(b) After 1 minute remove mortar and compress into 2� 4 inch cylinder in two layers using flat end of a rodor fingers, being sure to see that mold is solidly filled.(c) Lightly tap cylinder immediately and maintain indamp condition.(d) After 48 hours remove mold and store in fog roomuntil testing.

15.2.6.2 Grout

When required by the special provision or requested bythe Engineer, the Contractor shall manufacture groutprisms for testing. Prisms shall be manufactured at the siteduring construction using the following procedure:

(a) Place masonry units, having same moisture condi-tion as those being placed, on nonabsorptive base toform a void for a square prism with a height twice theside and a minimum side of 3 inches.(b) Line the side faces of the prism with permeablepaper or porous separator to allow water passagethrough liner into masonry units.(c) Fill prism with a fully representative grout samplein two layers. Puddle each layer to eliminate air voids.(d) Level off specimen and maintain in a damp condi-tion.(e) Remove prisms from masonry units after 48 hoursand deliver to Engineer.

Grout prisms will be tested in accordance with the pro-visions of ASTM C 39. Grout shall have attained a com-pressive strength of 2,000 psi at 28 days unless otherwisespecified in the special provisions.

15.3 CONSTRUCTION


Block or brick masonry shall not be constructed infreezing weather or when the block or brick contains frost,except by written permission of the Engineer and subjectto such conditions as he or she may require.

15.3.2 Laying Block and Brick

The blocks or bricks shall be laid in such manner aswill thoroughly bond them into the mortar by means of the

“shove-joint” method; “buttered” or plastered joints willnot be permitted. All clay or shale brick must be thor-oughly saturated with water before being laid. Dampen-ing of concrete masonry units before or during construc-tion shall not be permitted unless approved by theEngineer. The arrangement of headers and stretchers shallbe such as will thoroughly bond the mass and, unless oth-erwise specified, work shall be of alternate headers andstretchers with consecutive courses breaking joints. Othertypes of bonding, as for ornamental work, shall be asspecified on the plans.

All joints shall be completely filled with mortar. Theyshall not be less than 1⁄ 4 inch and not more than 5⁄ 8 inch inthickness and the thickness shall be uniform throughout.All joints shall be finished properly as the work progressesand on exposed faces they shall be neatly struck, using the“weather” joint.

No spalls or bats shall be used except for shapingaround irregular openings or when unavoidable to finishout a course, in which case full bricks shall be placed atthe corners, the bats being placed in the interior of thecourse.

Each masonry unit shall be adjusted to its final positionwhile mortar is still soft and plastic. Units which are dis-turbed after mortar has stiffened shall be removed and re-layed in fresh mortar.

Vertical cells to be filled with grout shall be aligned toprovide a continuous unobstructed opening.

Piers and walls may be built of solid brick work, ormay consist of a brick or block shell backed withconcrete or other suitable material as specified on theplans. All details of the construction shall be in accor-dance with approved practice and to the satisfaction ofthe Engineer.

15.3.3 Placement of Reinforcement

Prior to and during grouting the reinforcing steel shallbe securely held in position at the top and bottom and at intermediate points not exceeding 200 bar diameters or 10 feet apart. Bars shall be maintained clear of the cell walls and within plus or minus 1⁄ 2 inch of theirplanned position transverse to the wall and within plus orminus 2 inches of their planned position longitudinal tothe wall.

15.3.4 Grouting of Voids

Grouted masonry shall be constructed in such a man-ner that all elements of the masonry act together as a struc-tural element.



Prior to grouting, the grout space shall be clean so thatall spaces to be filled with grout do not contain mortar pro-jections greater than 1⁄ 2 inch, mortar droppings or otherforeign material. Grout shall be placed so that all spacesto be grouted do not contain voids.

Grout materials and water content shall be controlledto provide adequate fluidity for placement, without segre-gation.

Size and height limitations of the grout space or cell onthe average shall not be less than shown in Table 15.1.Higher grout pours or smaller cavity widths or cell sizethan shown in Table 15.1 may be used when approved bythe Engineer, if it is demonstrated that grout spaces areproperly filled.

When required by Table 15.1, cleanouts shall be pro-vided in the bottom course at every vertical bar but shallnot be spaced more than 32 inches on center for solidlygrouted masonry. Cleanouts shall be of sufficient size toallow removal of debris.

Units may be laid to the full height of the grout pourand grout shall be placed in a continuous pour in groutlifts not exceeding 6 feet. If construction joints are used incolumns of grout, they shall be located at least 11⁄ 2 inchesbelow the level of a mortar bed joint.

Segregation of the grout materials and damage to the masonry shall be avoided during the grouting process.

Grout shall be consolidated before loss of plasticity ina manner to fill the grout space. Grout pours greater than12 inches in height shall be mechanically reconsolidatedto minimize voids due to water loss. Grout not mechani-cally vibrated shall be puddled.

In nonstructural elements, mortar of pouring con-sistency may be substituted for grout when the masonry is constructed and grouted in pours of 12 inches or less.

Vertical barriers of masonry may be built across thegrout space. The grouting of any section of wall betweenbarriers shall be completed in 1 day with no interruptionlonger than 1 hour.

15.3.5 Copings, Bridge Seats, and Backwalls

The tops of retaining walls, abutment wingwalls, andsimilarly exposed brick or block work shall be provided,in general, with either a stone or concrete coping. The un-derside of the coping shall have a batter or drip bead, atleast 1 inch beyond the face of the block or brick workwall. The coping upon an abutment backwall will com-monly have no projection beyond its bridge seat face.When concrete is used, it shall conform to the require-ments for Class A concrete specified in Section 8, “Con-crete Structures.” For thin copings, mortar of the sameproportions as used for laying the block or brick may beused to produce precast sections not less than 3 feet normore than 5 feet in length. No coping shall be less than 4inches thick.

Copings of piers and abutment bridge seats shall be ofAshlar stone work or of Class A concrete and shall con-form to the requirements for “Ashlar Masonry” specifiedin Section 14, “Stone Masonry,” or for concrete as speci-fied in Section 8, “Concrete Structures,” as the plans may


TABLE 15.1 Grouting Limitations


indicate. Unless otherwise shown on the plans, concreteshall be used.


Concrete block and brick masonry will be measured bythe number of cubic yards or the number of square feet ofthe type of masonry actually placed in the structure in ac-cordance with the plans or as modified by written instruc-tions from the Engineer. The units of measure for the var-

ious types of masonry shall be as listed in the schedule ofbid items.

Concrete block and stone masonry, as measured above,will be paid for by the contract price per cubic yard orsquare foot. Such payment shall be considered to be fullcompensation for the cost of all labor, equipment, materi-als, and other expenses incidental to the satisfactory com-pletion of the work. Filling material for the interior of thewall, reinforcing steel, and concrete or mortar copings,shall be considered as included in the price paid for num-ber of cubic yards or square feet of block or brick masonryactually placed.



Section 16TIMBER STRUCTURES

16.1 GENERAL

This work shall consist of constructing timber struc-tures and the timber portions of composite structures, inaccordance with these Specifications and in reasonablyclose conformity with the details shown on the plans orestablished by the Engineer.

It will include furnishing, preparing, fabricating, erect-ing, treating, and painting of timber. All timber, treated oruntreated, shall be of the specified species, grades and di-mensions. Also included will be any required yard lumberof the sizes and grades specified and all hardware requiredfor timber connections and ties.

16.1.1 Related Work

Other work involved in the construction of timberstructures shall be as specified in the applicable sectionsof this specification. Some of the sections that frequentlyapply to timber structures are Section 4, “Driven Foun-dation Piles”; Section 13, “Painting”; Section 17, “Preservative Treatment of Wood”; and Section 20, “Railings.”

16.2 MATERIALS

16.2.1 Lumber and Timber (Solid Sawn or GluedLaminated)

Sawn lumber and timber shall conform to the Specifi-cations for Structural Timber, Lumber, and Piling,AASHTO M 168.

Structural glued laminated timber shall conform to theAmerican National Standard ANSI/AITC A-190.1, Spec-ification for Structural Glued Laminated Timber. Struc-tural glued laminated timber, as employed in ANSI/AITCA190.1, is an engineered, stress-rated product of a timberlaminating plant, comprising assemblies of suitably se-lected and prepared wood laminations securely bondedtogether with wet-use adhesives. The grain of all lamina-tions is approximately parallel longitudinally. The sepa-

rate laminations may not exceed 2 inches in net thick-ness. They may be comprised of pieces end-joined toform any length, of pieces placed or glued edge to edgeto make wider ones, or of pieces bent to curved formduring gluing. On glued-laminated structural membersthat are not to be preservatively treated, an approved end sealer shall be applied after end trimming of eachcompleted member.

The grades of timber used for various structuralpurposes shall be as shown on the plans or in the specialprovisions.

Structural lumber and timber, solid sawn or glued lam-inated, in exposed permanent structures, other than run-ning planks on decks, shall be treated in conformancewith the requirements of Section 17, “Preserved Treat-ment of Wood.” Temporary structures or lumber and tim-ber of certain species with adequate heartwood require-ments, as listed in AASHTO M 168, when permitted bythe plans or specifications, do not require preservativetreatment.

When the special provisions require certification ofquality for timber or lumber, the Contractor shall furnishthe following certificates of compliance to the Engineer,as appropriate, upon delivery of the materials to the jobsite:

For timber and lumber, a certification by an agencycertified by the American Lumber Standards Committeethat the timber or lumber conforms to the grade, species,and any other specified requirements.

For glued laminated timber, a certification by a quali-fied inspection and testing agency that the glued lami-nated timber complies with the grade, species, and otherrequirements outlined in ANSI/AITC A190.1.

If the wood is to be treated with a preservative, a cer-tificate of compliance, as specified in Article 17.3.3, shallbe furnished.

16.2.2 Steel Components

Rods, plates, eyebars, and shapes shall conform to therequirements of AASHTO M 270 (ASTM A 709) Grade36 unless otherwise specified.

607


16.2.3 Castings

Castings shall be cast steel or gray-iron, as specified,conforming to the requirements of Articles 11.3.5 or11.3.6.

16.2.4 Hardware

Bolts, nuts, drift-bolts, and dowels may be of mildsteel. Washers may be cast iron ogee or malleable ironcastings, or they may be cut from mild steel plate, as spec-ified.

Bolts shall have either standard square, hex or domeheads, or economy type (washer) heads. Nails shall be cutor round wire of standard form. Spikes shall be cut or wirespikes, or boat spikes, as specified. Unless otherwise spec-ified, bolts shall comply with ASTM A 307, and shall havecoarse threads, Class 2 tolerance conforming to ANSIStandard Specifications.

All fasteners, including nails, spikes, bolts, dowels,washers, and lag screws shall be galvanized, unless oth-erwise specified or permitted.

16.2.5 Galvanizing

16.2.5.1 Unless otherwise specified, all hardware fortimber structures shall be galvanized in accordance withAASHTO M 232 (ASTM A 153) or cadmium plated in ac-cordance with AASHTO M 299 (ASTM B 696). All steelcomponents, timber connectors, and castings, other thanmalleable iron, shall be galvanized in accordance withAASHTO M 111 (ASTM A 123).

16.2.6 Timber Connectors

16.2.6.1 Dimensions

The various types of timber connectors shall generallyconform to the dimensions shown in Table 16.1 and to thedimensions specified in this Article 16.2.6.

16.2.6.2 Split Ring Connectors

Split rings of 21⁄ 2-inch inside diameter and 4-inch in-side diameter shall be manufactured from hot-rolled car-bon steel conforming to the Society of Automotive Engi-neers Specification SAE-1010. Each ring shall form aclosed true circle with the principal axis of the cross sec-tion of the ring metal parallel to the geometric axis of thering. The metal section shall be beveled from the centralportion toward the edges to a thickness less than the mid-section. It shall be cut through in one place in its circum-ference to form a tongue and slot.

16.2.6.3 Shear-Plate Connectors

Pressed steel shear-plates of 25⁄ 8-inch diameter shall bemanufactured from hot-rolled carbon steel conforming tothe Society of Automotive Engineers Specification SAE-1010. Each plate shall be a true circle with a flange aroundthe edge, extending at right angles to the face of the plateand extending from one face only, the plate portion hav-ing a central bolt hole and two small perforations on op-posite sides of the hole and midway from the center andcircumference.

Malleable iron shear-plates of 4-inch diameter shall bemanufactured according to ASTM A 47, Grade 32510, formalleable iron casting. Each casting shall consist of a per-forated round plate with a flange around the edge extend-ing at right angles to the face of the plate and projectingfrom one face only, the plate portion having a central bolthole reamed to size with an integral hub concentric to thebolt hole and extending from the same face as the flange.

16.2.6.4 Spike-Grid Connectors

Spike-grid timber connectors shall be manufacturedaccording to ASTM A 47, Grade 32510, for malleable ironcasting.


TABLE 16.1 Typical Dimensions of TimberConnectors (dimensions in inches)


Square grids shall consist of four rows of opposingspikes forming a 41⁄ 8-inch square grid with 16 teeth thatare held in place by fillets. Fillets for the flat grid in crosssection shall be diamond shaped. Fillets for the singlecurve grids shall be increased in depth to allow for curva-ture and shall maintain a thickness between the slopingfaces of the fillets equal to the width of the fillet.

Circular grids of 31⁄ 4-inch diameter shall consist ofeight opposing spikes equally spaced around the outercircumference and held in place by connecting filletsaround the outer diameter and radial fillets projecting to

a central circular fillet which forms a bolt hole openingof 11⁄ 4 inch. Fillets in cross section shall be diamondshaped except that the inner circular fillet may be flat-tened on one side to provide for manufacturer identifi-cation.

16.3 FABRICATION AND CONSTRUCTION

16.3.1 Workmanship

Workmanship shall be first class throughout, and allframing shall be true and exact. Unless otherwise speci-fied, nails and spikes shall be driven with just sufficientforce to set the heads flush with the surface of the wood.Deep hammer marks in wood surfaces shall be consideredevidence of poor workmanship and sufficient cause for re-moval of the workman causing them.

16.3.2 Storage of Material

Lumber and timber stored at the construction site shallbe kept in orderly piles or stacks. Untreated material shallbe open-stacked on supports at least 12 inches above theground surface to avoid absorption of ground moistureand permit air circulation and it shall be so stacked andstickered as to permit free circulation of air between thetiers and courses. In particular cases required by the En-gineer, the Contractor shall provide protection from theweather by a suitable covering. The ground underneathand in the vicinity of the timber shall be cleared of weedsand rubbish. The storage area shall be chosen or con-structed so that water will not collect under or near thestored timber.

16.3.3 Treated Timber

16.3.3.1 Handling

Treated timber shall be carefully handled without sud-den dropping, breaking of outer fibers, bruising, or pene-trating the surface with tools. It shall be handled with webslings. Cant hooks, peaveys, pikes, or hooks shall not beused. When metal bands are used to bundle members, cor-ner protectors shall be provided to prevent damage to thetreated timber.

16.3.3.2 Framing and Boring

All cutting, framing, and boring of treated timbers shallbe done before treatment insofar as is practicable. Whentreated timbers are to be placed in waters infested by ma-rine borers, untreated cuts, borings, or other joint framingsbelow high-water elevation shall be avoided.


TABLE 16.1 (Continued)


16.3.3.3 Cuts and Abrasions

All cuts and all recesses formed by countersinking increosote treated piles or timbers, and all abrasions, afterhaving been carefully trimmed, shall be field treated asspecified either in this paragraph or the following para-graph. Cuts and recesses shall be covered with two appli-cations of a mixture of 60% creosote oil and 40% roofingpitch or brush coated with at least two applications of hotcreosote oil and covered with hot roofing pitch. Recesseslikely to collect injurious materials shall be filled with hotroofing pitch. Unless specified otherwise, hot preserva-tives shall be heated to a temperature between 150° and200°F. Where particularly heavy coatings are required, asuitable plastic compound can be prepared by mixing 10% to 20% of creosote and 80% to 90% of coal-tar roof-ing pitch.

For timbers originally treated with pentachlorophenol,creosote, creosote solutions or water-borne preservatives,all cuts, abrasions and recesses which occur after treat-ment shall be field treated by two liberal applications of acompatible preservative in accordance with the require-ments of the American Wood Preservers AssociationStandard M 4 entitled, “Standard for the Care of PressureTreated Wood Products.”

16.3.3.4 Bored Holes

All holes bored after treatment shall be treated by fill-ing the holes with the preservative used for field treatment.After treatment, any holes not filled with bolts or otheritems shall be plugged with preservative treated plugs.

16.3.3.5 Temporary Attachment

Whenever, with the approval of the Engineer, forms ortemporary braces are attached to treated timber with nailsor spikes, the resulting holes shall be treated as requiredfor bored holes and shall be filled by driving galvanizednails, spikes, or preservative-treated plugs flush with thesurface.

16.3.4 Installation of Connectors

Timber connectors shall be one of the following types,as specified on the plans: the split ring, the shear plate, orthe spike grid. The split ring and the shear plate types shallbe installed in precut grooves of dimensions as givenherein or as recommended by the manufacturer. Spikegrids shall be forced into the wood so that timbers will bein firm contact. Pressure equipment that does not damagethe wood shall be utilized. One acceptable method is touse high-strength bolts or rods fitted with low friction

ball-bearing washers made for this purpose. The high-strength bolt will be replaced with specified bolts for thefinal installation. All connectors of this type at a joint shallbe embedded simultaneously and uniformly.

Connector grooves in timber shall be cut concentricwith the bolt hole, shall conform to the cross-sectionalshape of the rings, and shall provide a snug fit. Insidegroove diameter shall be larger than nominal ring diame-ter in order that the ring will expand slightly during in-stallation. (See Table 16.1.)

Fabrication of all structural members using connectorsshall be done prior to preservative treatment. When pre-fabricated from templates or shop details, bolt holes shallnot be more than 1⁄ 16 inch from required placement. Boltholes shall be 1⁄ 16 inch larger than the finished bolt diame-ter. Bolt holes shall be bored perpendicular to the face ofthe timber.

Timber after fabrication shall be stored in a mannerthat will prevent changes in the dimensions of the mem-bers before assembly. Timber should be cured before fab-rication so that it will remain stable in its dimensions.Timber that shrinks during storage causing predrilledgrooves for split rings or plates to become elliptical orcausing bolt hole spacing to change will be sufficient rea-son for rejection.

16.3.5 Holes for Bolts, Dowels, Rods, and LagScrews

Holes for round drift-bolts and dowels shall be boredwith a bit 1⁄ 16 inch less in diameter than the bolt or dowelto be used. The diameter of holes for square drift-bolts ordowels shall be equal to the least dimension of the bolt ordowel.

Holes for machine bolts shall be bored with a bit thesame diameter as the finished bolt, except as otherwiseprovided for bolts in connectors.

Holes for rods shall be bored with a bit 1⁄ 16 inch greaterin diameter than the finished rod.

Holes for lag screws shall be bored with a bit not largerthan the body of the screw at the base of the thread. Toprevent splitting or stripping the threads, the hole for theshank shall be bored the same diameter and to the samedepth as the shank. The depth of holes for lag screws shallbe approximately 1 inch less than the length under thehead.

16.3.6 Bolts and Washers

A washer, of the size and type specified, shall be usedunder all bolt heads (except for timber bolts with economytype heads) and nuts which would otherwise come in con-tact with wood.



The nuts of all bolts shall be effectually locked afterthey have been finally tightened.

16.3.7 Countersinking

Countersinking shall be done where smooth or flushsurfaces are required. All recesses in treated timber,formed for countersinking, shall be treated as specified inArticle 16.3.3.3. Recesses likely to collect injurious ma-terials shall be filled with hot roofing pitch.

16.3.8 Framing

All lumber and timber shall be accurately cut andframed to a close fit in such manner that the joints willhave even bearing over the entire contact surfaces. Mor-tises shall be true to size for their full depth and tenonsshall fit snugly. No shimming will be permitted in makingjoints, nor will open joints be accepted.

16.3.9 Framed Bents

16.3.9.1 Mud Sills

Mud sills shall be firmly and evenly bedded to solidbearing and tamped in place. Mud sills shall be pressurepreservative treated for ground contact. Where untreatedtimber is permitted for mud sills, it shall be of heart cedar,heart cypress, redwood, or other durable timber as ap-proved by the Engineer.

16.3.9.2 Concrete Pedestals

Concrete pedestals for the support of framed bentsshall be carefully finished so that the sills or posts willtake even bearing. Dowels for anchoring sills or postsshall be not less than 3⁄ 4 inches in diameter and project atleast 6 inches above the tops of the pedestals. These dow-els shall be cast in the concrete pedestals. Concrete and re-inforcing steel shall conform to the requirements of Sec-tions 8, “Concrete Structures,” and 9, “Reinforcing Steel,”respectively.

16.3.9.3 Sills

Sills shall have true and even bearing on mud sills,piles, or pedestals. They shall be drift-bolted to mud sillsor piles with bolts of not less than 3⁄ 4-inch diameter andextending into the mud sills or piles at least 6 inches, orby other types of connectors as detailed on the plans.When possible, all earth shall be removed from contactwith sills so that there will be free air circulation aroundthe sills.

16.3.9.4 Posts

Posts shall be fastened to pedestals with dowels of notless than 3⁄ 4-inch diameter, extending at least 6 inches intothe posts, or by other types of connectors as detailed onthe plans.

Posts shall be fastened to sills by one of the followingmethods, as indicated on the plans:

(a) By dowels of not less than 3⁄ 4-inch diameter, ex-tending at least 6 inches into posts and sills.(b) By drift-bolts of not less than 3⁄4-inch diameter driv-en diagonally through the base of the post and ex-tending at least 9 inches into the sill. Drift bolts shall bedriven in holes as required by Article 16.3.5 at a 45°angle and shall enter the post at least 6 inches above thepost base.(c) By other types of connectors as detailed on theplans.

16.3.9.5 Caps

Timber caps shall be placed, with ends aligned, in amanner to secure an even and uniform bearing over thetops of the supporting posts or piles. All caps shall be se-cured by drift-bolts of not less than 3⁄ 4-inch diameter, ex-tending at least 9 inches into the posts or piles, or by othertypes of connectors as detailed on the plans. The drift-bolts shall be approximately in the center of the post orpile.

16.3.9.6 Bracing

Bracing shall be bolted through the pile, post, or capat the ends and at all intermediate intersections using abolt of not less than 5⁄ 8 inches in diameter. Bracing shallbe of sufficient length to provide a minimum distance of8 inches between the outside bolt and the end of thebrace.

16.3.10 Stringers

Stringers shall be sized at bearings and shall be placedin position so that knots near edges will be in the top por-tions of the stringers.

Outside stringers may have butt joints with the ends cuton a taper, but interior stringers shall be lapped to takebearing over the full width of the floor beam or cap at eachend. The lapped ends of untreated stringers shall beseparated at least 1⁄ 2 inch for the circulation of air and shallbe securely fastened by drift-bolting where specified.When stringers are two panels in length the joints shall bestaggered.



Unless otherwise specified in the contract, cross-bridg-ing or blocking shall be placed at the center of each span.Cross-bridging between stringers shall be neatly and ac-curately framed and securely toe-nailed with at least twonails in each end. All cross-bridging members shall havefull bearing at each end against the sides of stringers.Blocking shall be snug-fit and held in place by either pre-fabricated galvanized steel beam hangers or by tie-rods asdetailed on the plans.

16.3.11 Plank Floors

Unless otherwise specified, planks for flooring shall besurfaced four sides (S 4 S).

Single plank floors shall consist of a single thicknessof plank supported by stringers or joists. The planks shallbe laid heart side down, with 1⁄ 4-inch openings betweenthem for seasoned material and with tight joints for un-seasoned material. Each plank shall be securely spiked toeach joist. The planks shall be carefully graded as tothickness and so laid that no two adjacent planks shallvary in thickness by more than 1⁄ 8 inch.

Two-ply timber floors shall consist of two layers offlooring supported on stringers or joists. The top courseshall be laid either diagonal or parallel to the center lineof roadway, as specified, and each floor piece shall be se-curely fastened to the lower course. Joints shall be stag-gered at least 3 feet. If the top flooring is placed parallelto the center line of the roadway, special care shall betaken to securely fasten the ends of the flooring. At eachend of the bridge these members shall be beveled.

16.3.12 Nail Laminated or Strip Floors

The strips shall be placed on edge, at right angles to thecenter line of roadway. Each strip shall be nailed to thepreceding strip as shown in Figure 16.3. The spikes shallbe of sufficient length to pass through two strips and atleast half-way through the third strip.

If timber supports are used, every other strip shall be toe-nailed to every other support. The size of the spikes shall be as shown on the plans. When specified onthe plans, the strips shall be securely attached to steel supports by the use of approved galvanized metal clips.Care shall be taken to have each strip vertical and tightagainst the preceding strip, and bearing evenly on all thesupports.

16.3.13 Glue Laminated Panel Decks

Unless otherwise specified, deck panels shall be pres-sure preservative treated with creosote or pen-tachlorophenol with Type A, C, or D carrier. When it is not

possible to complete the fabrication and drilling of glulammembers for field connections before treating, a preserv-ative treatment shall be applied to cut or drilled areas inthe field, in accordance with Articles 16.3.3.3 and16.3.3.4.

Panels shall not be dragged or skidded. Glue laminateddeck panels shall be handled, and transported in a way toprevent bending the panels, especially transverse to thelaminated pieces. When lifted, they shall be supported ata sufficient number of points to avoid overstressing, andthe edges shall be protected from damage.

When dowels are shown on the drawings between deckpanels, a template or drilling jig shall be used to ensurethat dowel holes are accurately spaced. The holes shall bedrilled to a depth 1⁄ 4 inch greater than one-half the dowellength and of the same diameter as the dowel unless oth-erwise shown on the drawings. A temporary dowel shallbe used as a check for snug fit prior to production drilling.The dowels shall be of the size shown on the drawingswith the tips slightly tapered or rounded. A lubricant maybe used to facilitate the connection process.

The tips of the dowels shall be partially and equallystarted into the holes of the two panels being joined. Thepanels shall be drawn together keeping the edges parallel,until the panels abut tightly. Each panel shall be securelyfastened to each stringer or girder as shown on the draw-ings.

16.3.14 Composite Wood-Concrete Decks

Shear connectors needed to resist shear and providehold-down capacity between timber and concrete ele-ments which are designed for composite action shall befurnished and installed in conformance with the detailsshown on the plans or specified in the special provisions.If no such details are provided and the construction is de-scribed on the plans as being composite, the Contractorshall submit working drawings for such details and de-vices for approval by the Engineer before the subject workis begun.

16.3.15 Wheel Guards and Railing

Wheel guards and railing shall be accurately framed inaccordance with the plans and erected true to line andgrade. Unless otherwise specified, wheel guards, rails, andrail posts shall be surfaced four-sides (S 4 S). Wheelguards shall be laid in sections not less than 12 feet long,except where necessary to match expansion joints or endjoints.

Railings shall conform to the requirements in Section20, “Railings.”



16.3.16 Trusses

Trusses, when completed, shall show no irregularitiesof line. Chords shall be straight and true from end to endin horizontal projection and, in vertical projection, shallshow a smooth curve through panel points conforming tothe correct camber. All bearing surfaces shall fit accu-rately. Uneven or rough cuts at the points of bearing shallbe cause for rejection of the piece containing the defect.

16.4 PAINTING

Rails and rail posts of timber and any other parts des-ignated on the plan or in the special provisions to bepainted shall be painted with three coats of specificationpaint. Paint and its application shall conform to the re-quirements in Section 13, “Painting.”

Metal parts, except for hardware, galvanized or cad-mium plated metal, and malleable iron, shall be given onecoat of shop paint and, after erection, two coats of fieldpaint as specified in Section 13, “Painting.”

16.5 MEASUREMENT

The quantities to be paid for will be the number ofthousand feet board measure (Mbm) of each species andgrade of lumber and timber listed in the schedule of biditems, complete in place and accepted. Measurements oflumber and timber will be computed from the nominal di-mensions and actual lengths. The cross-sectional dimen-sions on the plans will be interpreted as standard sizes.The standard cross-sectional dimensions will be used in

the computations even though the actual size is less in thedimension specified.

Timber in wheel guards will be included. Timber in pil-ing, railing, and other items for which separate paymentis provided will not be included.

Measurements for glued laminated girders and beamswill be computed from the applicable finished dimensionsand actual lengths. Quantities for glue laminated girdersand beams to be paid for will be the linear feet for eachsize and stress combination.

The measurement of lumber and timber and of gluedlaminated girders and beams will include only such mate-rial as is a part of the completed and accepted work, andwill not include materials used for erection purposes, suchas falsework, bracing, sheeting, etc.

16.6 PAYMENT

Payment for timber, lumber, and glued laminatedgirders and beams shall be considered to be full compen-sation for all costs of furnishing of materials, includinghardware and timber connectors, preservative treatment,equipment, tools, and labor for the fabrication, erection,and painting necessary to complete all of the work incompliance with the plans and specifications in a satis-factory manner.

Metal parts, other than hardware and timber connec-tors, will be measured and paid for as provided in Section23, “Miscellaneous Metal.”

Railings and concrete will be measured and paid for asprovided in Sections 20, “Railings” and 8, “ConcreteStructures,” respectively.


FIGURE 16.3 Nail Placement Pattern


Section 17PRESERVATIVE TREATMENT OF WOOD

17.1 GENERAL

This work shall consist of treating wood, includinglumber, timber, piles and poles, with designated preserv-atives in accordance with these Specifications. It shall in-clude furnishing all materials, preparing, treating, andperforming all work to complete treating the wood prod-ucts required for the project.

The type of preservative treatment required shall be asspecified in the special provisions or as noted on the plans.

When a specific type of preservative is not called for,the kind of preservative to be used shall be adopted for itssuitability to the conditions of exposure to which it will besubjected and shall be subject to approval of the Engineer.

The handling and care of treated woods shall conformto the requirements of Sections 4, “Driven FoundationPiles,” and 16, “Timber Structures.”

17.2 MATERIALS

17.2.1 Wood

Piling shall conform to the requirements of Section 4,“Driven Foundation Piles.” Timber and lumber shall con-form to the requirements of Section 16, “Timber Struc-tures.”

17.2.2 Preservatives and Treatments

Timber preservatives and treatment methods shall con-form to AASHTO M 133. The type of preservative fur-nished shall be in accordance with that specified or asnoted on the plans. It should be noted that AASHTO M133 designates the preservatives and retentions recom-mended for Coastal Waters and in marine structures andfurther that timber for use in “ground or water contact”has requirements that differ from timbers for use “not inground or water contact.” In some instances there is arange of retentions offered which provides for differentdegrees of exposure based on climate or degree of insectinfestation. Unless the higher retentions are specified, notless than the minimum retention is required.

Unless otherwise specified in the Special Provisions or shown on the design drawings, timber railings and posts and timber that are to be painted shall be treatedwith pentachlorophenol with a Type C solvent or with a water-borne preservative of either Type CCA orACZA.

17.2.3 Coal-tar Roofing Cement

For purposes of these specifications pitch, coal-tarpitch, coal-tar roofing pitch, or coal-tar roofing compoundshall mean coal-tar roofing cement wherever the terms areused. Coal-tar roofing cement is a residue of the manu-facturing of coke and creosote from bituminous coal. Itshall be a thick, heavy-bodied, and paste-like material.When called for, it can be mixed with creosote. It may ormay not contain fibrous material.

17.3 IDENTIFICATION AND INSPECTION

17.3.1 Branding and Job Site Inspection

Each piece of treated timber shall bear a legiblebrand, mark, or tag indicating the name of the treater andthe specification symbol or specification requirements towhich the treatment conforms. Treated wood productsbearing the quality mark of the American Wood Pre-servers Bureau (AWPB) will be acceptable. The Engi-neer shall be provided adequate facilities and free accessto the necessary parts of the treating plant for inspectionof material and workmanship to determine that the con-tract requirements are met. The Engineer reserves theright to retest all materials after delivery to the job siteand to reject all materials which do not meet the re-quirements of the contract; provided that, at the job sitereinspection, conformance within 5% of contract re-quirements shall be acceptable. Reinspection at the jobsite may include assay to determine retention of preser-vatives and extraction and analysis of preservative to de-termine its quality.

615


17.3.2 Inspection at Treatment Plant

Unless otherwise specified, inspection of materials andpreservative treatment shall be the responsibility of theContractor and the supplier of treated wood products. In-spections shall be conducted in accordance withAASHTO Specification M 133 (AWPA Standards) by thetreater or an independent commercial inspection agencyapproved by the American Wood Preservers Bureau(AWPB) and the Engineer.

The inspection agency shall be engaged by the Con-tractor directly or through his or her supplier. No directcompensation will be made for these inspection costs, itbeing understood that the costs of inspection are includedin the contract bid prices for treated wood products or con-struction items of work.

17.3.3 Certificate of Compliance

Whenever specified or requested by the Engineer, acertificate of compliance with copies of the inspection re-ports attached shall be furnished to the Engineer with eachshipment of material. Such certificates shall identify thetype of preservative used and the quantity in pounds percubic foot (assay method) and shall be signed by thetreater or the qualified independent inspection agency.


No separate measurement and payment will be madefor preservative treatment as such work is a part of thework included in furnishing preservative treated materials.



Section 18BEARINGS

18.1 SCOPE

This section covers the construction and installation ofstructural bearings that consist of one or more of the fol-lowing component types: metal rocker and roller bearings,PTFE sliding bearings (flat and curved), plain elastomericpads, fiberglass reinforced elastomeric pads, cotton duckreinforced pads, steel reinforced elastomeric bearings, potbearings, disc bearings, and bronze and copper alloy bear-ings (flat and curved). At the discretion of the Engineer,other component types may be used, but the construction,installation and testing requirements must then be agreedby the Engineer before the start of fabrication.

The section also covers ancillary items such as ma-sonry, sole and load distribution plates, bedding materials,anchor bolts, lubricants and adhesives.

18.2 APPLICABLE DOCUMENTS

18.2.1 AASHTO Standards

The following AASHTO Standards are relevant to thissection.

AASHTO M 102 Steel Forgings, Carbon and Alloyfor General Use (ASTM A 668)

AASHTO M 107 Bronze Castings for Bridges andTurntables (ASTM B 22)

AASHTO M 108 Rolled Copper-Alloy Bearing andExpansion Plates and Sheets forBridges and Other Industrial Uses(ASTM B100)

AASHTO M 164 High-Strength Bolts for StructuralSteel Joints (ASTM A 325)

AASHTO M 251 Specifications for Plain and SteelLaminated Bearings for Bridges(ASTM D 4014)

AASHTO M 253 Heat-Treated Steel StructuralBolts 150 Ksi Minimum TensileStrength (ASTM A 490)

AASHTO M 270 Structural Steel for Bridges (ASTMA 709)

18.2.2 ASTM Standards

The following ASTM Standards are relevant to thissection.

ASTM A 167 Specification for Stainless and Heat-Resisting Chromium-Nickel SteelPlate Sheet, and Strip.

ASTM A 240 Specification for Heat-ResistingChromium and Chromium-NickelStainless Steel Plate, Sheet, and Stripfor Pressure Vessels

ASTM A 307 Specification for Carbon Steel Exter-nally Threaded Standard Fasteners

ASTM A 781 Standard Specification for Castings,Steel and Alloy, Common Require-ments, for General Industrial Use

ASTM A 788 Specification for Steel Forgings,General Requirements

ASTM A 802 Practice for Steel Castings, Texturesand Discontinuities, Evaluation andSpecifying by Visual Examination

ASTM B 22 Bronze Castings for Bridges andTurntables (AASHTO M 107)

ASTM B 29 Specification for Pig LeadASTM B 36 Specification for Brass Plate, Sheet,

Strip, and Rolled BarASTM B 100 Specification for Rolled Copper

Alloy Bearing and Expansion Platesfor Bridge and Other Structural Uses(AASHTO M 108)

ASTM B 103 Specification for Phosphor-BronzePlate, Sheet, Strip and Rolled Bar

ASTM B 438 Specification for Sintered BronzeBearings (Oil Impregnated)

ASTM D 395 Test Methods for Rubber Property—Compression Set

ASTM D 412 Test Methods for Rubber Property—Tension Test

ASTM D 429 Test Methods for Rubber Property—Peel Test

ASTM D 518 Test Method for Rubber Deteriora-tion—Surface Cracking

ASTM D 573 Test Method for Rubber—Deteriora-tion in an Air Oven

617


ASTM D 746 Test Method for Brittleness Temper-ature of Plastics and Elastomers byImpact

ASTM D 792 Test Method for Specific Gravity(Relative Density) and Density ofPlastics by Displacement

ASTM D 903 Test Method for Peel or StrippingStrength of Adhesive Bonds

ASTM D 1043 Stiffness Properties of Plastics as aFunction of Temperature by Meansof a Torsion Test

ASTM D 1149 Test Method for Rubber Deteriora-tion—Surface Ozone Cracking in aChamber.

ASTM D 1777 Method of Measuring Thickness ofTextile Materials

ASTM D 2000 Classification System for RubberProducts in Automotive Applications

ASTM D 2240 Test Method for Rubber Property—Durometer Hardness

ASTM D 2256 Test Method for Breaking Load(Strength) and Elongation of Yarn bythe Single-Strand Method

ASTM D 3293 Specification for PTFE ResinMolded Sheet

ASTM D 4014 Specification for Plain and Steel-Laminated Elastomeric Bearings forBridges (AASHTO M 251)

ASTM D 4894 Specification for Polytetrafluoroeth-ylene (PTFE) Granular Molding andRam Extrusion Materials

ASTM D 4895 Specification for Polytetrafluoroeth-ylene (PTFE) Resin Produced fromDispersion

18.2.3 Other Standards

ANSI/AASHTO/ Bridge Welding CodeAWS D1.5

MIL-S-8660C Grease for pot bearing rotationalelements

MMM-A-134 Epoxy (Federal specification)QQ-B-626 Brass (Federal specification)TT-S-230 Caulk (Federal specification)

18.3 GENERAL REQUIREMENTS

Bearings shall be constructed in accordance with thedetails shown on the plans and specifications. When com-plete details are not provided, bearings shall be furnishedthat conform to the limited details shown on the plans andshall provide the performance characteristics specified.

18.4 MATERIALS

18.4.1 General

18.4.1.1 Steel

18.4.1.1.1 Rolled steel shall be of the type requiredon the plans and shall satisfy the testing requirements ofthe standard to which it conforms. Unless otherwise spec-ified, it shall conform to AASHTO M 270 (ASTM A 709)Grade 36 and shall cause no adverse electrolytic or chem-ical reaction with other components of the bearing. It shallbe free of all rust and mill scale.

18.4.1.1.2 Unless otherwise specified by the Engineer,steel laminates in steel reinforced elastomeric bearingsshall be made from rolled mild steel conforming to M 270Grade 36, Grade 50 (ASTM A 36, A 572), or equivalent,and shall have a nominal thickness not less than 16 gage.Holes in laminates, not specified on the plans but used formanufacturing purposes, shall be permitted only with thewritten approval of the Engineer.

18.4.1.1.3 Cast steel shall satisfy the requirements ofASTM A 802 and be free of all blow-holes and impuritieslarger than 1 ⁄8 inch. The inside wall of the pot in pot bear-ings and the contact surface of metal rocker or roller bear-ings shall be free of blow-holes or impurities of any size.

18.4.1.1.4 Forged steel shall satisfy the requirementsof ASTM A 788.

18.4.1.1.5 Unless otherwise specified by the Engi-neer, stainless steel shall conform to ASTM A 167 or A240 type 304, and have a minimum thickness of 20 gage.Stainless steel in contact with PTFE sheet shall be pol-ished to a #8 mirror finish.

18.4.1.1.6 Steel weld metal shall be chosen to becompatible with the parent materials and the weldingprocess used and shall be approved by the Engineer.Stainless steel weld used for overlays shall be type 309L.

18.4.1.1.7 Bolts shall conform to AASHTO M 164(ASTM A 325), AASHTO M 253 (ASTM A 490) orASTM A 307 unless specified otherwise.

18.4.2 Special Material Requirements for MetalRocker and Roller Bearings

The steel at the contact surface of a metal bearing maybe hardened provided that, after hardening, it satisfies thestrength and ductility requirements of the contract plansand material specifications.



18.4.3 Special Material Requirements for PTFESliding Surfaces

18.4.3.1 PTFE

18.4.3.1.1 PTFE resin shall be 100% pure new mate-rial and shall comply with ASTM D 4894 or D 4895. Itshall satisfy the requirements of Table 18.4.3.1-1. No re-claimed material shall be used.

Finished PTFE sheet, strip and fabric shall be resistantto acids, alkalis, and petroleum products, stable at tem-peratures from �360°F to �500°F, nonflammable, andnonabsorbing of water.

18.4.3.1.2 Filler material, when used in PTFE, shallbe milled glass fiber, carbon fiber or other approved fiber.The filler shall not react chemically with the PTFE butshall adhere to it so that the two act compositely.

18.4.3.1.3 Finished PTFE sheet shall be made fromvirgin PTFE resin or virgin PTFE resin uniformly blendedwith approved filler. The maximum filler content shall be15% for fiberglass and 25% for carbon fibers. The maxi-mum filler content for other materials shall be determinedby the Engineer. The PTFE sheet shall satisfy the require-ments of Table 18.4.3.1-1. Values for intermediate fillercontents may be obtained by interpolation.

18.4.3.1.4 Woven fabric PTFE shall be made fromoriented multi-filament PTFE fibers or from a mixture ofPTFE fibers made from twisted, slit PTFE tape and otherfibers. It shall conform to the requirements of Table18.4.3.1-1.

18.4.3.2 Adhesives

Adhesive used for bonding sheet PTFE shall be anepoxy material satisfying the requirements of federal

specification MMM-A-134, FEP film or equal, as ap-proved by the Engineer.

18.4.3.3 Lubricants

Lubricant, if used, shall consist of a combination ofsolids which does not react chemically or electrolyticallywith the PTFE and its mating surface and shall remain sta-ble in the environmental conditions expected at the bridgesite.

18.4.3.4 Interlocked Bronze and Filled PTFEStructures

The phosphor bronze back plate shall conform toAASHTO M 108 (ASTM B 100) and the porous bronzelayer shall conform to ASTM B 103.

18.4.4 Special Material Requirements for PotBearings

18.4.4.1 The rotational element of the pot bearingshall be made from an elastomeric compound, with a hard-ness of 50 � 10 on the Shore A scale. It shall be made fromall new material. The raw polymer on which it is basedshall be either polychloroprene (neoprene) or polyisoprene(natural rubber). The compound shall satisfy the physicalproperty requirements for a 50 hardness material as speci-fied in Tables 18.4.5.1-1A or -1B.

18.4.4.2 The elastomer may be lubricated with a sili-cone grease which does not react chemically with the elas-tomer and which does not alter its properties within the rangeof environmental conditions expected at the bridge site.

18.4.4.3 The sealing rings shall be made of brass con-forming to ASTM B 36 (half hard) for rings of rectangularcross-section, and to federal specification QQ-B-626, com-position 2, for rings of circular cross-section. The Engineer


TABLE 18.4.3.1-1 Physical Properties of PTFE

ASTM Sheet Sheet with 15% Sheet with 25% WovenPhysical Property Test Method (Unfilled) glass fibers carbon fibers fabric

Specific Gravity D 4894, D 4895, 2.16 � 0.03 2.20 � 0.03 2.10 � 0.03 —or D 5977

Melting point (°F) D 4894, D 4895, .623 � 2 .621 � 18 .621 � 18 —or D 5977

Tensile Strength (psi) D 4894, D 4895, 28001 20002 13002 24,000or D 5977

Elongation at Break (%) D 4894, D 4895, 2001 1502 752 24,0351

or D 5977

1 Using Test Method ASTM D 22562 Using Test Method ASTM D 638


may, at own discretion, approve other sealing ring materi-als on the basis of test evidence which demonstrates ade-quate sealing properties and durability of the material.

18.4.5 Special Material Requirements for SteelReinforced Elastomeric Bearings andElastomeric Pads

18.4.5.1 Elastomer

The raw elastomer shall be either virgin neoprene(polychloroprene) or virgin natural rubber (polyisoprene).The elastomer compound shall be classified as being oflow temperature grade 0, 2, 3, 4 or 5. The grades are de-fined by the testing requirements in Tables 18.4.5.1-1Aand -1B. A higher grade of elastomer may be substitutedfor a lower one. In the absence of more specific informa-tion, bearings shall be Grade 3, 60 durometer elastomer.

The elastomer compound shall meet the minimum re-quirements of Tables 18.4.5.1-1A and -1B except as oth-erwise specified by the Engineer. The nominal hardness ofthe compound shall lie between 50 and 60 for reinforcedbearings and between 50 and 70 for plain pads. Test re-quirements may be interpolated for intermediate hardness.If the material is specified by its shear modulus, its mea-sured shear modulus shall lie within 15% of the specifiedvalue. A consistent value of hardness shall also be sup-plied for the purpose of defining limits for the tests in Ta-bles 18.4.5.1-1A and -1B. If the hardness is specified, themeasured shear modulus must fall within the range ofTable 14.6.5.2.1 in Article 14.6.5.2 of Division I. Whentest specimens are cut from the finished product, the phys-ical properties shall be permitted to vary from those spec-ified in Tables 18.4.5.1-1A and -1B by 10%. All materialtests shall be carried out at 73° � 4°F unless otherwisenoted. Shear modulus tests shall be carried out using theapparatus and procedure described in annex A of ASTMD 4014, amended where necessary by the requirements ofTables 18.4.5.1-1A or -1B.

18.4.5.2 Fabric Reinforcement

Fabric reinforcement shall be woven from 100% glassfibers of “E” type yarn with continuous fibers. The mini-mum thread count in either direction shall be 25 threadsper inch. The fabric shall have either a crowfoot or an 8Harness Satin weave. Each ply of fabric shall have a min-imum breaking strength of 800 lb/in. of width in eachthread direction.

18.4.5.3 Bond

The vulcanized bond between fabric and reinforce-ment shall have a minimum peel strength of 30 lb/in. Steel

laminated bearings shall develop a minimum peel strengthof 40 lb/in. Peel strength tests shall be performed byASTM D 429 Method B.

18.4.6 Special Material Requirements for Bronze or Copper Alloy Sliding Surfaces

18.4.6.1 Bronze and Copper Alloys

18.4.6.1.1 Bronze

Bronze components shall conform to the requirements ofAASHTO M 107 (ASTM B 22) alloy C90500, C91100 orC86300. Alloy C91100 shall be furnished unless otherwisespecified. Components may be cast, rolled or forged. Cast-ings shall be free of blow-holes larger than 1 ⁄8 inch and con-tact surfaces shall be free of all blow-holes of any size.

18.4.6.1.2 Rolled Copper-Alloy

Rolled copper-alloy bearing and expansion plates shallconform to the Specification for Rolled Copper-Alloy Bear-ing and Expansion Plates and Sheets for Bridge and OtherStructural Uses, AASHTO M 108 (ASTM B 100). Alloy No.C51000 or No. C51100 shall be furnished unless otherwisespecified.

18.4.6.2 Oil Impregnated Metal Powder SinteredMaterial

Metal powdered sintered material shall conform to ASTMB 438, Grade 1, Type II or Grade 2, Type I.

18.4.7 Special Material Requirements for DiscBearings

18.4.7.1 Elastomeric Rotational Element

The rotational element of the disc bearing shall bemade from an elastomeric compound with a hardnesswhich lies between 45 and 65 on the Shore D scale. Theraw polymer on which it is based shall be polyether ure-thane. The compound shall satisfy the physical propertyrequirements appropriate to the material’s hardness inTable 18.4.7.1-1.

18.4.8 Special Material Requirements for Guides

18.4.8.1 Low-Friction Material

The sliding interface shall be made from a materialwhich is approved by the Engineer and which will providea friction coefficient no greater than the one used in thedesign.




TABLE 18.4.5.1-1A Material Tests—polychloroprene

as described inannex A ofASTM D 4014



TABLE 18.4.5.1-1B Material Tests—polyisoprene

as described inannex A ofASTM D 4014


18.4.8.2 Adhesive

Any adhesive used to attach the sliding interface material shall be recommended for that purpose by themanufacturer of the sliding material and approved by the Engineer.

18.4.9 Special Requirements for Bedding Materials

18.4.9.1 Fabric-Reinforced Elastomeric Bedding Pads

Preformed fabric pads used as bedding shall be com-posed of multiple layers of 8-ounce cotton duck impreg-nated and bonded with high quality natural rubber or ofequivalent and equally suitable materials compressed intoresilient pads of uniform thickness. The number of pliesshall be such as to produce the specified thickness, aftercompression and vulcanizing. The finished pads shallwithstand compression stress perpendicular to the planeof the laminations of not less than 10,000 pounds persquare inch without detrimental reduction in thickness orextrusion.

18.4.9.2 Sheet Lead

Sheet lead used as bedding shall be common desilver-ized lead conforming to ASTM B 29. The sheets shall beof uniform thickness and shall be free from cracks, seams,slivers, scale, and other defects. Unless otherwise speci-fied, lead sheet thickness shall be 1 ⁄8 inch � 0.03 inch.

18.4.9.3 Caulk

Caulking material used as bedding shall be a nonsagpolysulfide or polyurethane material conforming to Fed-eral Specification TT-S-230, Type II.

18.4.9.4 Grout and Mortar

Grout and mortar used for filling under masonry platesshall conform to Article 8.14.

18.5 FABRICATION

18.5.1 General

18.5.1.1 Bearings shall be accurately machined tothe dimensions and tolerances shown on the contractplans and shall be free from flaws.

18.5.1.2 All fabrication from steel plate shall complywith Section 11.4 of Division II of this specification.

All welding shall conform to, and all welders shall bequalified in accordance with, the requirements of theANSI/AASHTO/AWS D 1.5 Bridge Welding Code.

18.5.1.4 If a masonry plate is used, the bearing shallbe attached to it by a method that permits transfer of allthe specified loads, but also allows replacement of thebearing. Recessing is recommended.

18.5.1.5 Unless specified otherwise, the dimensionaltolerances and surface finishes of the bearing shall satisfythe requirements of Table 18.5.1.5-1.

18.5.2 Special Fabrication Requirements for MetalRocker and Roller Bearings

18.5.2.1 Steel

Rocker bearings may be made by casting, forging orfabricating from plate. Roller bearings more than 9 inchesin diameter shall be forged and annealed. Smaller rollerbearings may either be forged and annealed or be madefrom cold-finished carbon steel shafting.

In roller bearings more than 9 inches in diameter, ahole not less than 2 inches in diameter shall be bored fulllength along the axis after the forging has cooled to a tem-perature below the critical range and before annealing. Itshall be done under conditions which prevent damage bycooling too rapidly.

18.5.2.2 Lubricant

Lubrication shall be applied to all gear mechanismsand to all other components of roller bearings for which itis required. The type of lubricant shall be as specified onthe contract plans, and shall be applied in accordance withthe manufacturer’s recommendations.


TABLE 18.4.7.1-1 Physical Properties of Polyether Urethane

ASTMTest

Physical Property Method Requirements

Hardness, Durometer ‘D’ D 2240 45 55 65Minimum Tensile Stress (psi) D 412

at 100% elongation 1500 1900 2300at 200% elongation 2800 3400 4000

Tensile Strength (psi) D 412 4000 5000 6000Elongation at break (%) D 412 350 285 220Maximum Compression Set D 395 40 40 40

(22 hrs @ 158° F, %)



TABLE 18.5.1.5-1 Fabrication Tolerances and Surface Finish Requirements

Flatness or Thickness Dimension out-of-round Surface finish

Item tolerance tolerance tolerance (�-in.) (rms.)

Metal Rocker & Roller BearingsSingle Roller: diameter — �0.063�, �0.063� �0.001�, �0.001� 63Nested Roller: diameter — �0.002�, �0.002� �0.001�, �0.001� 63Rockers: diameter — �0.125�, �0.125� �0.001�, �0.001� 125Pins: diameter — �0.005�, �0.000� �0.002�, �0.002� 32Bushings: diameter — �0.000�, �0.005� �0.002�, �0.002� 32

Pot BearingsOverall dimensions �0.000�, �0.250� �0.000�, �0.125� — —Pot depth (inside) — �0.000�, �0.025� — —Pot wall: thickness & ave. I.D. �0.000�, �0.125� �0.003�, �0.003� �0.001�, �0.001� 32Pot base: top & bottom surfaces �0.000�, �0.025� — Class C 63Piston: rim �0.000�, �0.063� �0.003�, �0.003� �0.001�, �0.001� 32Piston: top and bottom surfaces �0.000�, �0.025� — Class C 63Elastomeric disk (unstressed) �0.000�, �0.125� �0.063�, �0.000� — —

Disc BearingsOverall dimensions �0.000�, �0.250� �0.000�, �0.125� — —Shear-restricting element — �0.000�, �0.005� Class A 32Other machined parts �0.000�, �0.063� �0.000�, �0.063� Class B 63Urethane disc �0.000�, �0.063� �0.000�, �0.125� Class B 63

Flat PTFE Sliding BearingsPTFE �0.000�, �0.063� �0.000�, �0.030� Class A —Stainless steel �0.000�, �0.063� �0.000�, �0.125� Class A #8 mirror

Flat Bronze and Copper Alloy Sliding BearingsSliding surfaces �0.000�, �0.125� �0.000�, �0.125� Class A 32

Curved PTFE Sliding BearingsConvex radius — �0.010�, �0.000� �0.002�, �0.002� #8 mirrorConcave radius — �0.000�, �0.010� �0.002�, �0.002� 125

Steel-reinforced Elastomeric BearingsOverall dimensions �0.000�, �0.250� �0.000�, �0.250� — —Internal rubber layers �0.125�, �0.125� — — —

& �0.20* designCover �0.000�, �0.125� — — —Parallelism: top & bot. surfaces �0.005 radians — — —Parallelism: sides — �0.020 radians — —

Elastomeric PadsOverall dimensions �0.000�, �0.125� �0.000�, �0.250� — —

GuidesContact surface — �0.000�, �0.125� Class A 32Distance between guides — �0.000�, �0.030� — —Parallelism of guides — �0.005 radians — —

Load PlatesOverall dimensions �0.063�, �0.063� �0.250�, �0.250� Class A† 125†

Bevel slope �0.002 radians — — —

Notes: Flatness: Class A � 0.001 � nominal dimensionClass B � 0.002 � nominal dimensionClass C � 0.005 � nominal dimension

† only for surfaces in contact with the bearing


18.5.3 Special Fabrication Requirements for PTFESliding Bearings

18.5.3.1 Fabrication of PTFE

Each PTFE element shown on the plans as a singlepiece shall be so fabricated and supplied.

18.5.3.2 Attachment of PTFE

18.5.3.2.1 Flat Sheet PTFE

All flat sheet PTFE attached to a metal backing plate shall be attached by recessing into the backing platefor one half of the PTFE thickness and bonding. PTFE attached to other materials, such as elastomers, shall be attached by a method approved by the Engineer.

The PTFE shall be factory-bonded, using an adhesivethat is approved by the Engineer, in accordance with the in-structions of the adhesive’s manufacturer. Prior to bonding,the surface shall be etched by an approved manufacturerusing the sodium napthalene or sodium ammonia process.When the backing plate is metal, the bonding shall be conducted under a uniform pressure greater than 100 psi.

The peel strength of the bond shall be not less than 20lb/in, tested in accordance with ASTM D 429 Method B.The finished surface of the PTFE shall be smooth, freefrom bubbles and shall conform to the tolerances shownin Table 18.5.1.5-1. Filled PTFE sheets shall be polishedafter bonding.

18.5.3.2.2 Curved Sheet PTFE

Curved sheet PTFE, such as used in spherical bearings,shall be attached by recessing for one half of the PTFEthickness. The dimensions of the PTFE element shall beselected so that it fits tightly in the recess even when thebearing is subjected to its lowest design temperature.

18.5.3.2.3 Woven PTFE Fabric

Fabric made from woven PTFE fibers shall be bondedor mechanically fastened to a rigid substrate in such a waythat the fabric can carry a compressive stress of 10,000 psiwithout cold flow. The attachment of the fabric to the sub-strate shall be capable of withstanding, without delamina-tion, a shear force equal to (0.1 � �)P at the same time asthe normal load P, where � is the design coefficient offriction between the PTFE and its mating surface and P isthe design load acting perpendicularly to the interface.

18.5.3.3 Stainless Steel Mating Surface

Each stainless steel element shown on the plans as asingle piece shall be so supplied. Each sheet shall be at-

tached to its backing material by seal welding around theentire perimeter so as to prevent entry of moisture be-tween the stainless steel and the backing material. Weldsshall conform to the American Welding Society require-ments for stainless steel. After welding, the stainless steelsheet shall be flat, free from wrinkles and in continuouscontact with its backing plate.

18.5.3.4 Lubrication

Lubricant shall be applied to the entire PTFE surface ifspecified by the Engineer. If the PTFE is dimpled, enoughlubricant shall be used to fill all the dimples.

18.5.4 Special Fabrication Requirements forCurved Sliding Bearings

All mating parts of any bearing shall be furnished bythe manufacturer.

Sheet PTFE shall be attached to the metal backing sur-face by recessing in accordance with Article 18.5.3.2.2.

Unless otherwise specified by the Engineer, the PTFEshall be bonded to its metal backing surface using an ad-hesive that is recommended by the manufacturer and ap-proved by the Engineer. While the adhesive sets, thePTFE shall be compressed between the two matingcurved metal surfaces under a pressure of at least 100 psi.

18.5.5 Special Fabrication Requirements for Pot Bearings

18.5.5.1 Pot

The pot shall be made by forging, casting, fabricationby welding or machining from a single piece of plate. Inpots made by welding a ring to a base plate, the weld shallbe a full penetration butt weld.

The piston shall be machined from a single piece ofsteel. The outside diameter of the piston shall be no morethan 0.030 inches less than the inside diameter of the potat the level of the interface between the piston and elas-tomeric rotational element. The sides of the piston shall bebeveled to facilitate rotation.

If guides are used, they may be attached to the pistonby welding or bolting.

18.5.5.2 Sealing Rings

The sealing rings shall be recessed into the elastomericdisk and shall fit snugly against the pot wall. Rings of rec-tangular cross section shall be installed with their gapsequally spaced around the circumference. The gap betweenthe ring and the wall shall nowhere exceed 0.01 inches.



The gap between the cut ends of the ring shall not exceed0.05 inches.


The elastomeric pad shall have the same nominal di-ameter as the pot. It may be individually molded or cutfrom sheet. It may be made of no more than three separatelayers, of which none may have a nominal thickness ofless than 1 �2 inch. The sealing ring recess depth shall bethe same as the total ring thickness if rectangular rings areused.

18.5.6 Special Fabrication Requirements for SteelReinforced Elastomeric Bearings andElastomeric Pads

18.5.6.1 Requirements for All ElastomericBearings

Bearings and pads which are designed to act as a sin-gle unit with a given shape factor shall be manufacturedas a single unit.

Flash tolerance, finish, and appearance shall meet therequirements of the latest edition of the Rubber Handbookas published by the Rubber Manufacturers Association,Inc., RMA F3 and T.063 for molded bearings and RMAF2 for extruded bearings.

18.5.6.2 Steel Laminated Elastomeric Bearings

Bearings with steel laminates shall be cast as a unit ina mold and shall be bonded and vulcanized under heatand pressure. The mold finish shall conform to standardshop practice. The internal steel laminates shall be sand-blasted and cleaned of all surface coatings, rust, millscale and dirt before bonding, and shall be free of sharpedges and burrs. External load plates (sole plates) shallbe protected from rusting by the manufacturer, andpreferably should be hot bonded to the bearing duringvulcanization.

18.5.6.3 Fabric Reinforced Elastomeric Pads

Fabric-reinforced elastomeric pads may be vulcanizedin large sheets and cut to size. Cutting shall be performedin such a way as to avoid heating the materials and shallproduce a smooth finish with no separation of the fabricfrom the elastomer. Fabric reinforcement shall be at leastsingle ply for the top and bottom reinforcement layers anddouble ply for internal reinforcement layers. Fabric shallbe free of folds and ripples and shall be parallel to the topand bottom surfaces.

18.5.6.4 Plain Elastomeric Pads

Plain pads may be molded, extruded, or vulcanized inlarge sheets and cut to size. Cutting shall not heat the ma-terial, and shall produce a smooth finish.

18.5.7 Special Fabrication Requirements for Bronzeand Copper Alloy Bearings

18.5.7.1 Bronze Sliding Surfaces

Bronze plates shall be cast according to details shownon the plans. Unless detailed otherwise, sliding surfacesshall be machined parallel to the direction of movementand polished.

18.5.7.2 Copper Alloy Plates

Copper alloy plates shall be furnished according to details shown on the plans. Rolled plates need not be finished provided they have a plane, true and smooth surface.

18.5.8 Special Fabrication Requirements for DiscBearings

18.5.8.1 Steel Housing

The steel housing of the disc bearing shall be made bymachining from a single piece of plate or by fabricationby welding.

The shear restriction mechanism shall be connected tothe bearing plate by mechanical fastening, welding orother means approved by the Engineer.


The polyether urethane rotational element shall bemolded as a single piece. The finish of the mold shall befree from burrs and shall conform to good shop practice.

18.5.9 Special Fabrication Requirements for Guides

18.5.9.1 Guide bars shall be attached to the body ofthe bearing by a method which minimizes distortion andallows the flatness tolerances on all parts of the bearing tobe met after attachment. The sliding surfaces of the guidesystem shall be flat and parallel.

18.5.9.2 Bolts or threaded fasteners used to attachthe guide bars to their supporting plates shall have an em-bedded thread length adequate to develop their requiredstrength.



18.5.9.3 If low friction material is used at the contactinterface, it shall be attached to its backing piece by twoor more of the following methods simultaneously: bond-ing, recessing and mechanical attachment with counter-sunk fasteners.

If the material is bonded, it shall first be etched by themethod recommended by the manufacturer of the mater-ial or the bonding agent. Recessing shall be one half of thematerial thickness. Fasteners shall be countersunk to adepth which ensures that they will not touch the matingmaterial after allowing for wear.

18.5.10 Special Requirements for Load Plates

Load plates shall be made from a single steel plate orthey may be built up from several steel laminates, eachoriented in the plane perpendicular to the direction of theload. Built up load plates shall be joined by complete sealwelding to prevent ingress of moisture. Such welds shallalso provide sufficient shear strength to resist the appliedloads. The load plates shall have no sharp corners oredges. Holes may be formed by drilling, punching, or accurately controlled oxygen cutting. All burrs shall be removed by grinding.

18.5.11 Special Requirements for Anchor Bolts

Anchor bolts shall be provided with anchorage detailsthat permit development of the full tension strength of thebolt. Hooks or end plates are recommended.

18.6 CORROSION PROTECTION

After fabrication, steel surfaces exposed to the atmos-phere, except stainless steel surfaces, shall be cleaned andcoated to protect against corrosion in accordance with thecontract plans and specifications.

Areas to be welded shall be free of all rust, moisture,and foreign material at the time of welding. The requiredfinal cleaning and coating of these surfaces shall be doneafter the completion of welding.

18.7 TESTING AND ACCEPTANCE

18.7.1 General

18.7.1.1 Scope

Testing and acceptance criteria for bearings shall con-form to the minimum requirements laid out in this section.The Engineer may require more stringent standards.

The tests shall be conducted in accordance with the re-quirements of Article 18.7.2. The minimum frequency oftesting for different bearing types is set out in Article 18.7.4.

When bearings are made from a number of compo-nents, each component shall satisfy the testing require-ments from the applicable section.

The Engineer, or his or her assigned agents, shall begiven free access to inspect the manufacturer of the bear-ings at all times.

18.7.1.2 Definitions

Load Range—A load range is a range of load capacities inwhich the highest capacity is no more than 2.0 times aslarge as the lowest.

Lot—A lot is a group of no more than 25 bearings of thesame type (e.g. elastomeric or pot bearings, and fixed,guided or floating), in the same load range.

Batch—A batch is a body of material in which the ingre-dients are uniformly blended together at one time.

Sample—A sample is a piece of material or a completebearing which is tested in order to infer the propertiesof the batch of material or group of bearing elementsfrom which it is taken. A sample shall consist of at leastone bearing chosen randomly from each lot and mater-ial batch and shall comprise at least 10% of the lot.

18.7.1.3 Test Pieces to be Supplied to theEngineer

If required by the Engineer, the Manufacturer shallsupply material samples from the batches used in the bear-ings and two finished bearings for inspection and testingat a site of the Engineer’s choice.

18.7.1.4 Tapered Sole Plates

Each bearing with a tapered sole plate that is selectedfor testing shall be delivered to the test site accompaniedby an unattached plate identical to the tapered sole plate.The single beveled plate shall be so constructed that,when placed in contact with the tapered sole plate, thetwo shall form a single body, rectangular in shape anduniform in thickness.

18.7.2 Tests

The tests prescribed in Articles 18.7.2.2-18.7.2.9 shallbe carried out at the manufacturer’s expense. Unless oth-erwise agreed by the Engineer, they shall be supervised by an independent testing agency.

18.7.2.1 Material Certification Tests

Material certification tests to determine the physicaland chemical properties of all materials shall be con-ducted in accordance with the appropriate specification



governing the material. The test certificates shall be pro-vided to the Engineer.

18.7.2.2 Material Friction Test (Sliding SurfacesOnly)

The coefficient of friction between the two mating sur-faces shall be measured. Samples taken from the samebatch of materials as those used in the prototype bearingsshall be used or the tests may, at the manufacturer’s op-tion, be conducted on finished bearings. Only new mate-rials shall be used, and no material that has been previ-ously tested shall be used.

The surfaces shall first be thoroughly cleaned with adegreasing solvent. No lubrication other than that speci-fied for the prototype bearings shall be used. The matingsurfaces for the test pieces shall have a common area noless than the smaller of the bearing area or 7 in2.

The test pieces shall be loaded in compression to a stresscorresponding to their maximum service dead plus liveload, which shall be held constant for 1 hour prior to andthroughout the duration of the sliding test. At least 100 cy-cles of sliding, each consisting of at least � 1 inch of move-ment, shall then be applied at a temperature of 68°F � 2°F.The uniform sliding speed shall be 2.5 inches/minute.

The breakaway friction coefficient shall be computedfor each direction of each cycle, and its mean and standarddeviation shall be computed for the sixth through twelfthcycles. The initial static breakaway coefficient of frictionfor the first cycle shall not exceed twice the design coef-ficient of friction. The maximum coefficient of friction forall subsequent cycles shall not exceed the design coeffi-cient of friction. Failure of a single sample shall result inrejection of the entire lot.

Following the 100 cycles of testing, the breakaway co-efficient of friction shall be determined again and shall notexceed the initial value. The bearing or specimen shallshow no appreciable sign of wear, bond failure or otherdefects.

18.7.2.3 Dimensional Check

The dimensions of the bearing shall be checked. Twotypes of dimensions, standard and critical, shall be mea-sured. For each component type, the standard and criticaldimensions are defined in the appropriate Article 18.7.3.The values of the critical dimensions shall be recordedand provided by the manufacturer to the Engineer. Failureof a critical dimension to satisfy its tolerance shall consti-tute absolute cause for rejection. Failure of a standardmeasurement to satisfy its tolerance shall, at the discretionof the Engineer, constitute cause for rejection.

Flatness shall be checked by placing a precision straight-edge on the surface to be checked and by inserting feelergages between the two. The straight-edge shall be placedat different orientations and the worst condition shall beestablished. No more than three feeler gages may bestacked on top of one another. The straight-edge shall beas long as the largest dimension of the flat surface. Flat-ness shall satisfy the requirements of Table 18.5.1.5-1.

18.7.2.4 Clearance Test

In a clearance check the components of the bearingshall be moved through their design displacements or ro-tations in order to verify that the required clearances exist.If the test is conducted on a rotational component whichis not under simultaneous full vertical load, allowanceshall be made for the displacements which would becaused by that load.

18.7.2.5 Short-term Compression Proof LoadTest

The bearing shall be loaded in compression to 150%of its rated service load. If a rotational element exists, atapered plate shall be introduced in the load train so thatthe bearing sustains the load at the maximum simultane-ous design rotation. The load shall be held for 5 minutes,removed, then reapplied for a second period of 5 minutes.The bearing shall be examined visually while under thesecond loading. Any defects shall constitute cause for re-jection. If the load drops below the required value duringeither application, the test shall be restarted from the be-ginning.

18.7.2.6 Long-term Compression Proof LoadTest

The test shall be conducted in the same way as theshort-term proof load test except that the second loadshall be maintained for 15 hours. If the load drops below90% of its target value during this time, the load shall beincreased to the target value and the test duration shall beincreased by the time for which the load was below therequired value.

18.7.2.7 Bearing Friction Test (for slidingsurfaces only)

The purpose of the Bearing Friction Test is to verifythat the friction values achieved in the material frictiontests are adequate predictors of the friction in the finishedbearing.



No lubrication shall be applied except that used for thewhole lot of bearings. The bearing shall be loaded in com-pression with 100% of the full service dead plus live load,which shall be held constant for one hour prior to andthroughout the duration of the sliding test. At least 12 cy-cles of sliding, each consisting of the smaller of the designdisplacement and � 1 inch of movement, shall then be ap-plied. The average sliding speed shall be 2.5 inches/minute.When the test is applied to curved sliding bearings, the de-sign rotation shall be used in place of the displacement.

In flat sliding bearings, the breakaway friction coeffi-cient shall be computed for each direction of each cycle,and its mean and standard deviation shall be computed forthe sixth through twelfth cycles. Neither the friction coef-ficient for the first movement nor the mean plus two stan-dard deviations for the sixth through twelfth cycles shallexceed the value used in design, and the mean value forthe sixth through the twelfth cycles shall not exceed twothirds of the value used in design.

In curved sliding surfaces, the moment correspondingto the design rotation shall be established at each peakmovement (positive and negative) during the first and lastsix full cycles of testing. The corresponding load eccen-tricity shall be calculated by dividing the moment by thetotal compressive load acting. The eccentricity shall besmall enough that the allowable stresses on the PTFE usedin design are not violated.

18.7.2.8 Long-term Deterioration Test

The purpose of the test is to verify the long-term resis-tance of the materials to creep, wear and deterioration.The test shall be conducted on samples of the materialsused in the bearings, or, at the option of the manufacturer,it may be conducted on a pair of bearings, placed back-to-back. The samples shall have an area not less than 7 in2.The test piece shall first be loaded in compression to astress corresponding to 100% of the maximum dead pluslive service load. Flat sliding systems shall then be dis-placed through at least 1000 cycles with an amplitude ofat least � 1 inch (2 inches peak to peak). Curved slidingsystems and rotational systems that depend on deforma-tion of an elastomeric element shall be subjected to dis-placements corresponding to 5000 cycles of rotation at � the design amplitude. The sliding may take place at upto 10 inches/minute, except when readings are taken ofthe coefficient of friction, when the sliding speed shall be2.5 inches/minute. The following shall be cause for rejec-tion of the bearing:

(1) Damage visible to the naked eye on disassembly ofthe bearing, such as excessive wear, cracks or splits inthe material.

(2) A coefficient of friction which exceeds two thirdsthe value used in design.

18.7.2.9 Bearing Horizontal Force Capacity(Fixed or Guided Bearings Only)

The purpose of the test is to verify that the bearing isstable and that the guide or restraint system has adequatestrength under the most severe combination of horizontaland vertical loads.

One or more loading combinations, consisting of a hor-izontal and vertical service load which could exist simul-taneously in the structure, shall be selected. The verticalload shall be applied first, at 1.0 times its nominal value.The horizontal load shall be applied in stages, up to 1.5times its nominal value. Failure or excessive deflection ofany of the components shall be cause for rejection.

18.7.3 Performance Criteria

If one bearing of the sample fails, all the bearings ofthat lot shall be rejected, unless the manufacturer elects totest each bearing of the lot at own expense. In lieu of thisprocedure, the Engineer may require every bearing of thelot to be tested.

18.7.4 Special Testing Requirements

18.7.4.1 Special Test Requirements for Rockerand Roller Bearings

Material certification tests shall be performed to estab-lish the material properties of the steel.

18.7.4.2 Special Test Requirements for PTFESliding Bearings

Inspection of the completed bearings or representativesamples of bearings with PTFE surfaces in the manufac-turer’s plant may be required by the Engineer. Inspectors,if appointed, shall be allowed free access to the necessaryparts of the manufacturer’s plant and test facility. Whentesting is performed by the manufacturer, copies of thetest results shall be submitted to the Engineer.

The manufacturer is required to perform material testson the materials used in the sliding surface in accordancewith Article 18.7.2.2. A minimum of one test must be per-formed for each lot of bearings.

If requested by the Engineer and available test facilitiespermit, complete bearings shall be tested for complete bear-ing friction as defined in Article 18.7.2.7. If the test facilitydoes not permit testing complete bearings, at the direction



of the Engineer, extra bearings may be manufactured by theContractor and samples of at least 100-kips capacity atnormal working stresses prepared by sectioning the bear-ings. As soon as all bearings have been manufactured for agiven project, notification shall be given to the Engineerwho will select the prescribed test bearings at random fromthe lot. Manufacturer’s certification of the steel, elastomericpads, preformed fabric pads, PTFE, and other materialsused in the construction of the bearings shall be furnishedalong with notification of fabrication completion.

18.7.4.3 Special Test Requirements for CurvedSliding Bearings

Curved PTFE sliding surfaces shall satisfy all of thetest requirements specified for PTFE sliding surfaces inArticle 18.7.4.2, except that, when the prototype bearingis too large to test, a test bearing may be especially man-ufactured using materials and fabrication methods that areidentical to those used for the prototype, in lieu of sec-tioning a bearing.

Critical dimensions shall include the difference be-tween the average radii of the two elements and the vari-ation of the actual curved surface from the average one.The Engineer may require verification of these critical di-mensions through a dimensional check as described in Ar-ticle 18.7.2.3.

18.7.4.4 Special Test Requirements for PotBearings

18.7.4.4.1 Material Certification Tests

The manufacturer shall select, at random, samples formaterial certification tests as defined in Article 18.7.2.1.The tests shall be performed, and certifications shall bedelivered to the Engineer.

Certification shall be provided for all elastomeric ele-ments. Their material properties shall satisfy the require-ments of the design documents and the tests described inArticle 18.7.4.5. Additional tests may be required by theEngineer.

18.7.4.4.2 Testing by the Engineer

When quality assurance testing is called for by the spe-cial provisions, the manufacturer shall furnish to the En-gineer the required number of complete bearings andcomponent samples to perform quality assurance testing.At least one elastomeric element shall be tested per lot ofbearings. All exterior surfaces of sampled productionbearings shall be smooth and free from irregularities orprotrusions that might interfere with testing procedures.

For quality assurance testing, the Engineer may selectat random the required sample bearing(s) and the mater-ial samples from completed lots of bearings or from stock.

A minimum of 30 days shall be allowed for inspection,sampling, and quality assurance testing of productionbearings and component materials.

18.7.4.4.3 Bearing Tests

Critical dimensions shall include the clearance be-tween the piston and pot, and shall be verified by theClearance Test described in Article 18.7.2.4.

A Long-term Deterioration Test as described in Article18.7.2.8 shall be performed on one bearing of each lot ofpot bearings with sealing rings other than rings with rec-tangular cross-sections satisfying Article 14.6.4.5.1 andcircular cross-sections satisfying Article 14.6.4.5.2. Thetest shall be performed at the maximum design rotationcombined with maximum dead plus live load. If size lim-itations prevent testing of the full size bearing, a specialbearing with the same sealing rings, the same rotationalcapacity and no less than 200 kips compressive load ca-pacity may be tested in its place.

A Long-term Compression Proof Load Test as de-scribed in Article 18.7.2.6 may be required by the Engineer.

18.7.4.5 Test Requirements for ElastomericBearings

18.7.4.5.1 Scope

Materials for elastomeric bearings and the finishedbearings themselves shall be subjected to the tests de-scribed in this section. Material tests shall be in accor-dance with the appropriate Table 18.4.5.1-1A or Table18.4.5.1-1B.

18.7.4.5.2 Frequency of Testing

The ambient temperature tests on the elastomer de-scribed in Article 18.7.4.5.3 shall be conducted for thematerials used in each lot of bearings. In lieu of perform-ing a shear modulus test for each batch of material, themanufacturer may elect to provide certificates from testsperformed on identical formulations within the precedingyear, unless otherwise specified by the Engineer. Test cer-tificates from the supplier shall be provided for each lot ofreinforcement.

The three low temperature tests on the elastomer de-scribed in Article 18.7.4.5.4 shall be conducted on the ma-terial used in each lot of bearings for grades 3, 4, and 5material and the instantaneous thermal stiffening test shallbe conducted on material of grades 0 and 2. Low temper-ature brittleness and crystallization tests are not required



for grades 0 and 2 materials, unless especially requestedby the Engineer.

For grade 3 material, in lieu of the low temperaturecrystallization test, the manufacturer may choose to pro-vide certificates from low-temperature crystallizationtests performed on identical material within the last year,unless otherwise specified by the Engineer.

Every finished bearing shall be visually inspected inaccordance with Article 18.7.4.5.5.

Every steel reinforced bearing shall be subjected to theshort-term load test described in Article 18.7.4.5.6.

From each lot of bearings either designed by the pro-visions of Article 14.6.5 of Division I of this specificationor made from grade 4 or grade 5 elastomer, a random sam-ple shall be subjected to the long-term load test describedin Articles 18.7.2.7 and 18.7.4.5.7. The sample shall con-sist of at least one bearing chosen randomly from eachsize and material batch and shall comprise at least 10% ofthe lot. If one bearing of the sample fails, all the bearingsof that lot shall be rejected, unless the manufacturer electsto test each bearing of the lot at own expense. In lieu ofthis procedure, the Engineer may require every bearing ofthe lot to be tested.

The Engineer may require shear stiffness tests on ma-terial from a random sample of the finished bearings in ac-cordance with Article 18.7.4.5.8.

18.7.4.5.3 Ambient Temperature Tests on theElastomer

The elastomer used shall at least satisfy the limits pre-scribed in the appropriate Table 18.4.5.1-1A or -1B fordurometer hardness, tensile strength, ultimate elongation,heat resistance, compression set, and ozone resistance.The bond to the reinforcement, if any, shall also satisfyArticle 18.4.5.3. The shear modulus of the material shallbe tested at 73°F � 2°F using the apparatus and proceduredescribed in Annex A of ASTM D 4014, amended wherenecessary by the requirements of Table 18.4.5.1-1A or -1B. It shall fall within 15% of the specified value, orwithin the range of its hardness given in Article 14.6.5.2of Division I if no shear modulus is specified.

18.7.4.5.4 Low Temperature Tests on the Elastomer

The tests shall be performed in accordance with the re-quirements of Tables 18.4.5.1-1A and -1B and the com-pound shall satisfy all limits for its grade. The testing fre-quency shall be in accordance with Article 18.7.4.5.2.

18.7.4.5.5 Visual Inspection of the Finished Bearing

Each finished bearing shall be inspected for compli-ance with dimensional tolerances and for overall quality

of manufacture. In steel reinforced bearings, the edges ofthe steel shall be protected everywhere from corrosion.

18.7.4.5.6 Short-Duration Compression Tests onBearings

Each finished bearing shall be subjected to a short-termcompression test as described in Article 18.7.2.5. If thebulging pattern suggests laminate parallelism or a layerthickness that is outside the specified tolerances, or poorlaminate bond, the bearing shall be rejected. If there arethree or more separate surface cracks that are greater than0.08 inches wide and 0.08 inches deep, the bearing shallbe rejected.

18.7.4.5.7 Long-Duration Compression Tests onBearings

The bearing shall be subject to a long-term compres-sion test as described in Article 18.7.2.6. The bearing shallbe examined visually at the end of the test while it is stillunder load. If the bulging pattern suggests laminate paral-lelism or a layer thickness that is outside the specified tol-erances, or poor laminate bond, the bearing shall be re-jected. If there are three or more separate surface cracksthat are greater than 0.08 inches wide and 0.08 inchesdeep, the bearing shall be rejected.

18.7.4.5.8 Shear Modulus Tests on Materials fromBearings

The shear modulus of the material in the finished bear-ing shall be evaluated by testing a specimen cut from itusing the apparatus and procedure described in Annex Aof ASTM D 1014, amended where necessary by the re-quirements of Table 18.4.5.1-1A or -1B, or, at the discre-tion of the Engineer, a comparable nondestructive stiff-ness test may be conducted on a pair of finished bearings.The shear modulus shall fall within 15% of the specifiedvalue, or within the range for its hardness given in Table14.6.5.2.1 of Division I if no shear modulus is specified.If the test is conducted on finished bearings, the materialshear modulus shall be computed from the measuredshear stiffness of the bearings, taking due account of theinfluence on shear stiffness of bearing geometry and com-pressive load.

18.7.4.7 Test Requirements for Bronze andCopper Alloy Bearings

Material certification tests for the bronze or coppershall be performed to verify the properties of the metal.

Bearing friction tests as defined in Article 18.7.2.7 ormaterial friction tests as defined in Article 18.7.2.2 maybe required by the Engineer.



18.7.4.8 Test Requirements for Disc Bearings

18.7.4.8.1 Material Certification Tests

The manufacturer shall select, at random, samples formaterial certification tests as defined in Article 18.7.2.1.The tests shall be performed, and certifications shall bedelivered to the Engineer.

Certification shall be provided for all polyether ure-thane elements. Their material properties shall satisfy therequirements of the design documents and the tests de-scribed in Article 18.4.8.1. Additional tests may be re-quired by the Engineer.

18.7.4.8.2 Testing by the Engineer

When quality assurance testing is called for by the spe-cial provisions, the manufacturer shall furnish to the En-gineer the required number of complete bearings andcomponent samples to perform quality assurance testing.At least one set of material property tests in accordancewith Article 18.4.8.1 shall be conducted per lot of bear-ings. All exterior surfaces of sampled production bearingsshall be smooth and free from irregularities or protrusionsthat might interfere with testing procedures.

For quality assurance testing, the Engineer may selectat random the required sample bearing(s) and the mater-ial samples from completed lots of bearings.

A minimum of 30 days shall be allowed for inspection,sampling, and quality assurance testing of productionbearings and component materials.

18.7.4.8.3 Bearing Tests

Critical dimensions shall include the clearance betweenthe upper and lower parts of the steel housing, and shall beverified by the Clearance Test described in Article18.7.2.4.

A Long-term Deterioration Test as described in Article18.7.2.8 shall be performed on one disc bearing of eachlot. The test shall be performed at the maximum design ro-tation combined with a maximum dead plus live load. Ifsize limitations prevent testing of the full size bearing, aspecial bearing with the same rotational capacity and noless than 200 kips compressive load capacity may betested in its place.

A Long-term Compression Proof Load Test as de-scribed in Article 18.7.2.6 may be required by the Engineer.

18.7.5 Cost of Transporting

The Contractor shall assume the cost of transporting allsamples from the place of manufacture to the test site andback, or if applicable, to the project site.

18.7.6 Use of Tested Bearings in the Structure

Bearings which have been satisfactorily tested in ac-cordance with the requirements of this section may beused in the structure provided that they are equipped withnew deformable elements, sliding elements and seals, asrequired by the Engineer.

18.8 PACKING, SHIPPING AND STORING

For transportation and storage, bearings shall be pack-aged in a way that prevents relative movement of theircomponents and damage by handling, weather, dust, orother normal hazards. They shall be stored only in a clean,protected environment. When installed, bearings shall beclean and free from all foreign substances.

Bearings shall not be opened or dismantled at the siteexcept under the direct supervision of, or with the writtenapproval of, the manufacturer or its assigned agents.

18.9 INSTALLATION

18.9.1 General Installation Requirements

Bearings shall be installed by qualified personnel at thelocations shown on the plans. Bearings shall be set to thedimensions and offsets prescribed by the manufacturer,the Engineer, and the plans and shall be adjusted as nec-essary to take into account the temperature and futuremovements of the bridge due to temperature changes, re-lease of falsework, shortening due to prestressing andother bridge movements.

Each bridge bearing shall be located within � 1 ⁄8 inchof its correct position in the horizontal plane and orientedto within an angular tolerance of 0.02 radians. GuidedBearings shall also satisfy the requirements of Article18.9.2.3. All bearings except those which are placed in op-posing pairs shall be set horizontal to within an angulartolerance of 0.005 radians, and must have full and evencontact with load plates, where these exist. The super-structure supported by the bearing shall be set on it so that,under full dead load, its slope lies within an angular toler-ance of 0.005 radians of the design value. Any departurefrom this tolerance shall be corrected by means of a ta-pered plate or by other means approved by the Engineer.If shim stacks are needed to level the bearing they shall beremoved after grouting and before the weight of the super-structure acts on the bearing.

Metallic bearing assemblies not embedded in the con-crete shall be bedded on the concrete with a filler or fab-ric material conforming to Article 18.4.9.

Bearings seated directly on steel work require the sup-porting surface to be machined so as to provide a level andplanar surface upon which the bearing is placed.



Bearings or masonry plates that rest on a steel supportmay be installed directly on it, provided that it is flat towithin a tolerance of 0.002 times the nominal dimension,and is sufficiently rigid that it will not deform under thespecified loads to exceed that flatness tolerance.

18.9.2 Special Installation Requirements

18.9.2.1 Installation of Rocker and RollerBearings

Just before placing roller bearings, the Contractor shallcoat all contact surfaces thoroughly with oil and graphite.

18.9.2.2 Installation of Elastomeric Bearings

Elastomeric bearings without external load plates maybe placed directly on a concrete or steel surface providedthat it is flat to within an tolerance of 0.005 of the nominaldimension for steel reinforced bearings and 0.01 of thenominal dimension for others. Bearings shall be placed onsurfaces that are horizontal to within 0.01 radians. Any lackof parallelism between the top of the bearing and the un-derside of the girder that exceeds 0.01 radians shall be cor-rected by grouting or as otherwise directed by the Engineer.

Exterior plates of the bearing shall not be welded un-less at least 1.5 inches of steel exists between the weld andthe elastomer. In no case shall the elastomer or the bondbe subjected to temperatures higher than 400° F.

18.9.2.3 Installation of Guideways andRestraints

Guided bearings and bearings which rotate about onlyone axis shall be oriented in the direction specified on the contract plans to within an angular tolerance of 0.005radians.

18.9.2.4 Installation of Anchorages

Load plates shall be set level to within an angular tol-erance of 0.005 radians and shall have a uniform bearingover their whole area. When plates are to be embedded inconcrete, provision shall be made to keep the plates in thecorrect position while the concrete is being placed.

A bedding layer may be used to achieve level, uniformbearing. This may consist of grout or a ductile metal suchas a thin lead sheet. The bedding material shall be able tosupport the specified vertical and horizontal loads withoutundergoing displacements or deformations detrimental tothe bearing or structure.

Anchor bolts embedded in concrete shall either be castinto the concrete or shall be grouted into drill holes.

18.10 DOCUMENTATION


The manufacturer shall submit to the Engineer shopdrawings and design calculations which are sufficientlydetailed to permit proper review of the bearings. Thedrawings shall show all details of the bearings and of thematerials proposed for use and must be approved by theEngineer before fabrication of the bearings is begun. Suchapproval shall not relieve the Contractor of any responsi-bility under the contract for the successful completion ofthe work. The drawings shall include, but not be limitedto the following information:

(1) Plan, elevations and sections including all nominaldimensions and material designations.(2) Vertical and horizontal load capacities, horizontalmovement capacities and rotation capacities about twohorizontal and one vertical axes.(3) Design calculations for all items not completelycovered in Section 14 of Division I of this specifi-cation.(4) Material designations and specifications.(5) A schedule of bearing offsets, if any are required.(6) Shop painting or coating requirements.(7) Any special installation requirements.

18.10.2 Marking

Each bearing shall be marked in indelible ink or flexi-ble paint. The marking shall consist of the location, orien-tation, order number, lot number, bearing identificationnumber, and elastomer type and grade number. Unless oth-erwise specified in the contract documents, the markingshall be on a face which is visible after erection of thebridge.

18.10.3 Certification

The manufacturer shall supply certification data for allmaterials used. This shall consist of at least test reports forthe bearing performance tests and for any forgings, castingsor hardened material, mill certificates for all other steelsused, and a certificate of compliance for the bearing as awhole and for any anchor bolts, dowels or other accessories.If the manufacturer designed the bearing, he shall certifythat each bearing satisfies the Engineer’s requirements,given under Division I, Section 14, “Bearings.”

The manufacturer shall also supply a separate sheetshowing the materials, critical dimensions and clear-ances for each bearing other than elastomeric pads. Theprecise information to be supplied shall be agreed be-tween the Engineer and the manufacturer prior to start-ing production.



18.11 MEASUREMENT

Bearing devices will be measured either by the poundas determined from scale weights or by a unit basis foreach type of bearing assembly listed in the schedule ofbid items. Scale weights are not required when calculatedweights are shown on the plans, in which case theweights shown on the plans will be used as the basis ofpayment.

18.12 PAYMENT

Bearing devices will be paid for at the contract priceper pound or per unit. Such payment shall include fullcompensation for furnishing all labor, materials, tools,equipment and incidentals, and for doing all the work in-volved in furnishing, testing and installing said bearingdevices, complete in place, as shown on the plans, and asspecified in these Specifications and the special provi-sions, and as directed by the Engineer.



Section 19BRIDGE DECK JOINT SEALS

19.1 GENERAL

This work shall consist of the furnishing and installingof joint sealing systems in bridge decks of the types usedwhere significant movements are expected across thejoint. These include compression seal joints consisting ofpreformed elastomeric material compressed and installedin specially prepared joints and joint seal assemblies con-sisting of assemblies of metal and elastomeric materialsinstalled in recesses in the deck surface.

Joint seals described in the plans or the specificationsas poured joint seals shall conform to the requirement ofArticle 8.9, “Expansion and Contraction Joints.”

The type and dimensions or movement rating forbridge deck joint seals at each location shall be as shownon the plans or ordered by the Engineer.

All joint seals shall prevent the intrusion of materialand water through the joint system.


If not given on the plans, calculations showing the jointsettings for their installation will be required before ap-proval to install joints in any bridge deck can be given.The Contractor will submit working drawings to the En-gineer showing the installation procedure and joint as-sembly for bridge decks using proprietary joint systems.Also, shop drawings shall be submitted to the Engineerfor approval for joints having a total movement of morethan 13⁄4 inches.


19.3 MATERIALS

Bridge deck joint seal materials and assemblies shallconform to the following specifications:

Preformed elastomeric joint seals of multiple web de-sign shall conform to AASHTO M 220 (ASTM D 2628).

Lubricant-adhesive for use with preformed elastomericseals shall conform to ASTM D 4070.

Deck joint seal assemblies shall be of an approved typefor each size required and shall conform to the specifica-tions provided by the manufacturer at the time of ap-proval.

Steel and fabricated steel components shall conform tothe requirements of Section 23, “Miscellaneous Metal.”

19.4 MANUFACTURE AND FABRICATION

19.4.1 Compression Seal Joints

Preformed elastomeric joint seals shall not be fieldspliced except when specifically permitted by the Engi-neer.

19.4.2 Joint Seal Assemblies

Expansion joint assemblies shall be fabricated by themanufacturer and delivered to the bridge site completelyassembled, unless otherwise shown on the plans or spec-ified in the special provisions.

19.5 INSTALLATION

19.5.1 General

All joint materials and assemblies, when stored at thejob site, shall be protected from damage and assembliesshall be supported so as to maintain their true shape andalignment. Deck joint seals shall be constructed and in-stalled to provide a smooth ride. Bridge deck joints shallbe covered over by protective material after installationuntil final cleanup of the bridge deck.

After installation and prior to final acceptance, deckjoint seals shall be tested in the presence of the Engineerfor leakage of water through the joint. Any leakage of thejoint seal will be cause for rejection.

635


19.5.2 Compression Seal Joints

Joints in the roadway area of bridge decks which are tobe sealed with compression seals shall be cast to a nar-rower width than required for the preformed material.Such joints in curbs and sidewalks may be cast to fullwidth. Prior to installation of compression seals in jointswhose width is narrower than needed, a groove of properwidth and depth to receive the preformed material shall besaw cut along the top of the joint.

When making saw cuts into the bridge deck, spallingshall be minimized. Both sides of a groove shall be cut si-multaneously to the proper depth and alignment as shownon the plans. The alignment of the saw shall be controlledat all times by a rigid guide. The width of the groove willdepend on the temperature and age of the concrete andshall be as directed by the Engineer. Lip of saw cut shouldbe bevelled to avoid later breakage. After saw cutting, anyspalls, popouts or cracks shall be repaired prior to instal-lation of the lubricant sealant. Saw cuts are not requiredwhere armor plates are used.

At the time of installation the joint shall be clean anddry and free from spalls and irregularities which mightimpair a proper joint seal. Concrete or metal surfaces shallbe clean, free of rust, laitance, oils, dirt, dust, or otherdeleterious materials. Premolded elastomeric compres-sion joint seals shall be installed without damage to theseal by suitable hand methods or machine tools. The lu-bricant-adhesive shall be applied to both faces of the jointprior to installation and in accordance with the manufac-turer’s instructions. The preformed elastomeric seal shall

be compressed to the thickness specified on the plans oras approved by the Engineer for the rated opening and am-bient temperature at the time of installation. Loose fittingor open points between the seal and the deck will not bepermitted.

19.5.3 Joint Seal Assemblies

Expansion joint seal assemblies shall be constructed toprovide absolute freedom of movement through a rangeconsistent with that prescribed by the Engineer or asshown on the design plans. Installation shall be in accor-dance with the manufacturer’s recommendations. Finalsettings of the deck joint seal assembly at the time of cast-ing in the anchorages of the unit depend on the relation-ship of the current temperature of the superstructure to itsexpected mean temperature, and shall be as specified bythe manufacturer or Engineer or as shown on the plans.


Deck joint seals will be measured by the linear foot ofacceptable joint seal completely installed by measure-ments made along the slope of the centerline of the jointseal.

Payment of linear feet of joint seal as measured, foreach type of seal for which separate payment is provided,shall include full compensation for the cost of labor,equipment and materials to furnish and install the deckjoint seal.



Section 20RAILINGS

20.1 GENERAL

20.1.1 Description

This work consists of furnishing all materials and con-structing railings on structures. The types of railings in-cluded in this work consist of handrailings, pedestrianrailings, traffic railings which are sometimes called barri-ers, and railings for other such purposes. Railings con-structed at each location shall conform to the type and de-tails shown on the plans for that location. The workincludes the furnishing and placing of mortar or concrete,anchor bolts, reinforcing steel dowels or other devicesused to attach the railing to the structure.

20.1.2 Materials

All materials not otherwise specified shall conform tothe requirements of the applicable AASHTO StandardSpecifications for Transportation Materials.

20.1.3 Construction

Unless otherwise permitted by the Engineer, railingshall not be placed until the centering or falsework for thespan has been released, rendering the span self-supporting.

20.1.4 Line and Grade

The line and grade of the railing shall be true to thatshown on the plans and may include an allowance forcamber in each span but shall not follow any unevennessin the superstructure. Unless otherwise specified or shownon the plans, railings on bridges, whether super-elevatedor not, shall be vertical.

20.2 METAL RAILING

20.2.1 Materials and Fabrication

20.2.1.1 Steel Railing

Materials and fabrication of steel railings shall con-form to the applicable requirements of Section 11, “Steel

Structures,” except that formed sections may be fabri-cated from mild steel, and pipe sections shall be of stan-dard steel pipe. Nuts and bolts not designated as highstrength shall conform to the requirements of ASTM A307 and steel tubing shall conform to the requirements ofASTM A 500, Grade B.

20.2.1.2 Aluminum Railing

For aluminum railings or portions of railings, cast alu-minum posts shall conform to the requirements ofAASHTO M 193; and extruded components shall con-form to the requirements of ASTM B 221.

20.2.1.3 Metal Beam Railing

Metal beam rail, posts and hardware shall conform tothe requirements in Section 606 of the AASHTO GuideSpecifications for Highway Construction.

20.2.1.4 Welding

All exposed welds shall be finished by grinding or fil-ing to give a smooth surface. Welding of aluminum mate-rials shall be done by an inert gas shielded, electric arcwelding process using no welding flux. Torch or flamecutting of aluminum will not be permitted.

20.2.2 Installation

Metal railings shall be carefully adjusted prior to fix-ing in place to ensure proper matching at abutting joints,correct alignment, and camber throughout their length.Holes for field connections shall be drilled with the rail-ing in place on the structure at proper grade and align-ment.

Where aluminum alloys come in contact with othermetals or concrete, the contacting surfaces shall be thor-oughly coated with a dielectric aluminum-impregnatedcaulking compound, or a synthetic rubber gasket may beplaced between the two surfaces.

637


20.2.3 Finish

Unless otherwise specified, anchor bolts, nuts and allsteel portions of railings shall be galvanized and alu-minum portions shall be unpainted. Galvanizing of rail el-ement shall conform to the requirements of AASHTO M111 (ASTM A 123) and galvanizing of nuts and bolts shallconform to the requirements of AASHTO M 232 (ASTMA 153). Minor abrasions to galvanized surfaces shall berepaired with zinc rich paint. After erection, all sharp pro-trusions shall be removed and the railing cleaned of dis-coloring foreign materials.

When painting is specified, the type and coating shallconform to the requirements of Section 13, “Painting,” orthe special provisions.

20.3 CONCRETE RAILING

20.3.1 Materials and Construction

Concrete railings, depending on the design, may beconstructed by the cast-in-place, precast or, when ap-proved by the Engineer, the slip form method.

All materials and construction shall conform to the re-quirements in Section 8, “Concrete Structures” and Sec-tion 9, “Reinforcing Steel.” Unless otherwise specified,concrete shall conform to Class AE except that Class Amay be used in areas where freezing seldom occurs. Whenthe minimum thickness of the railing at any point is lessthan 4 inches, Class C (AE) or, where freezing seldom oc-curs, Class C concrete may be used. Forms for cast-in-place railing shall not be removed until adequate mea-sures to protect and cure the concrete are in place and theconcrete has sufficient strength to prevent surface or otherdamage caused by form removal. Finish for railings con-structed with fixed forms shall be Class 2-Rubbed Finish.Finish for railings constructed with slip forms and fortemporary railings shall be Class I-Ordinary Finish.

20.4 TIMBER RAILING

Unless otherwise stated in the special provisions,posts, rails, and other timber for wood railings shall beconstructed according to the requirements of Section 16,“Timber Structures,” and Section 17, “Preservative Treat-ment of Wood.” When treated wood is called for, thepreservative treatment shall conform to the requirementsof Section 17, “Preventive Treatment of Wood.” The sur-

faces of all elements of treated wooden railings that are lo-cated where contact with people could occur shall besealed with two coats of an acceptable sealer. Acceptablesealers are urethane, shellac, latex epoxy, enamel and var-nish.

20.5 STONE AND BRICK RAILINGS

Stone and brick railings shall conform to the require-ments of Section 14, “Stone Masonry,” and Section 15,“Concrete Block and Brick Masonry.”

20.6 TEMPORARY RAILING

Temporary railings shall be constructed of materialsand to the details shown on the plans or specified. Railingsshall be properly joined and aligned at the required loca-tions. Temporary precast barriers shall be installed on asolid base. The temporary railing shall be maintained infirst class condition and shall not be removed until allwork requiring the railing has been completed. Previouslyused units may be employed provided they are in a cleanand undamaged condition. After removal, temporary rail-ing shall continue to be the property of the Contractor.


20.7.1 Measurement

Railings will be measured by the linear foot betweenthe ends of the railing or the outside ends of end posts,whichever is greater. Measurement will be made alongthe slope of the railing and no deductions will be madefor electrolier or other small openings called for on theplans.

20.7.2 Payment

Railings will be paid for by the contract prices per lin-ear foot for the various types listed in the schedule of biditems. Such payment shall include full compensation forfurnishing all labor, materials, equipment and incidentalsand for doing all work involved in constructing the rail-ings or barriers complete in place, including the furnish-ing and installation of reinforcing steel and steel dowelsor anchor bolts which are either placed or drilled andbonded into the structure for attachment of the railing.



Section 21WATERPROOFING

21.1 GENERAL

This work shall consist of furnishing and installing ma-terials to waterproof or dampproof concrete or masonrysurfaces. The surfaces to be waterproofed or dampproofedand the type of system to be installed shall be as shown onthe plans or otherwise specified.

21.1.1 Waterproofing

Waterproofing shall consist of either a constructed-in-place asphalt membrane system or a preformed membranesystem, both of which include appropriate priming mate-rials and, when required, protective coverings. Unless aspecific type of waterproofing system is shown on theplans or specified, the type of system to be used will be atthe option of the Contractor.

21.1.2 Dampproofing

Dampproofing shall consist of a coating of primer andtwo moppings of waterproofing asphalt.

21.2 MATERIALS

21.2.1 Asphalt Membrane Waterproofing System

21.2.1.1 Asphalt

Waterproofing asphalt shall conform to the Specifica-tion for Asphalt for Dampproofing and Waterproofing,AASHTO M 115 (ASTM D 312). Type I shall be usedbelow ground and Type II used above ground.

21.2.1.2 Primer

Primer for use with waterproofing asphalt shall con-form to the Specification for Primer for Use With Asphaltin Dampproofing and Waterproofing, AASHTO M 116(ASTM D 41).

21.2.1.3 Fabric

The fabric shall conform to either the Specification forWoven Cotton Fabrics Saturated with Bituminous Sub-

stances for Use in Waterproofing, AASHTO M 117(ASTM D 173) or the Specifications for Woven GlassFabric Treated with Asphalt, ASTM D 1663.

The Fabric shall be stored in a dry, protected place. Therolls shall not be stored on end.

21.2.2 Preformed Membrane WaterproofingSystems

21.2.2.1 Primer

Primer for use with the rubberized asphalt membraneshall be a neoprene based material, and the primer for usewith the modified bitumen membrane shall be a resin orsolvent based material. Primers shall be of a type recom-mended by the manufacturer.

21.2.2.2 Preformed Membrane Sheet

Preformed membrane sheet shall be of either the rub-berized asphalt type or the modified bitumen type. Therubberized asphalt type shall consist of a rubberized as-phalt sheet reinforced with a polyethylene film or mesh.The modified bitumen sheet type shall consist of a poly-mer modified bitumen sheet reinforced with a stitch-bonded polyester fabric or a fiberglass mesh. The mem-brane sheet shall conform to the following requirements:

For Surfaces Other Than Bridge Decks

639

(continued on next page)


21.2.2.3 Mastic

The mastic for use with preformed rubberized sheetsshall be a rubberized asphalt cold applied joint sealant.The mastic for use with modified bitumen sheet shall be ablend of bituminous and synthetic resins.

21.2.3 Protective Covers

Materials for protective covers shall conform to thefollowing unless another type is shown or specified.

For surfaces against which backfill will be placed, theprotective cover shall consist of 1⁄ 8-inch hardboard or othermaterial that will furnish equivalent protection fromdamage due to sharp coarse backfill material or fromconstruction equipment.

For roadway surfaces of bridge decks, the protectivecover shall consist of a layer of special asphalt concrete asspecified in the special provisions.

For horizontal surfaces above which reinforced con-crete structures are to be constructed, the protective covershall consist of a 2-inch course of concrete mortar con-forming to the requirements of Article 8.14 except that theproportions shall consist of 1 part Portland cement to 3parts of fine aggregate. This mortar course shall be rein-forced midway between its top and bottom surfaces with6 � 6—W1.4 � W1.4 welded wire fabric, or its equiva-lent. The top surface shall be finished smooth and true tograde.

21.2.4 Dampproofing

The primer and asphalt used for dampproofing shallconform to that specified in Article 21.2.1.

21.2.5 Inspection and Delivery

All waterproofing and dampproofing materials shall betested before shipment. Unless otherwise ordered by theEngineer, they shall be tested at the place of manufacture,and, when so tested, a copy of the test results shall be sentto the Engineer by the chemist or inspection bureau whichhas been designated to make the tests, and each packageshall have affixed to it a label, seal, or other mark of iden-tification, showing that it has been tested and found ac-ceptable, and identifying the package with the laboratorytests.

Factory inspection is preferred, but, in lieu thereof, theEngineer may order that representative samples, properlyidentified, be sent to him or her for test prior to shipmentof the materials. After delivery of the materials, represen-tative check samples shall be taken which shall determinethe acceptability of the materials.

All materials shall be delivered to the work in originalcontainers, plainly marked with the manufacturer’s brandor label.

21.3 SURFACE PREPARATION

All concrete surfaces which are to be waterproofed ordampproofed shall be reasonably smooth and free of for-eign material that would prevent bond and from pro-jections or holes which might cause puncture of themembrane or dampproofing. The surface shall be dry and,immediately before the application of the primer thesurface shall be thoroughly cleaned of dust and loosematerials.

No waterproofing or dampproofing shall be done inwet weather, nor when the surface temperature is below35°F, or that recommended by the manufacturer, withoutspecial authorization from the Engineer. Should the sur-face of the concrete become temporarily damp, it shall becovered with a 2-inch layer of hot sand, which shall be al-lowed to remain in place from 1 to 2 hours, or long enoughto produce a warm and surface-dried condition, afterwhich the sand shall be swept back, uncovering sufficientsurface for beginning work, and the operation repeated asthe work progresses.

21.4 APPLICATION

Waterproofing shall not be applied to any surface untilthe Contractor is prepared to follow its application withthe placing of the protective covering and backfill withina sufficiently short time that the membrane will not bedamaged by men or equipment, exposure to weathering,or from any other cause. Damaged membrane or protec-


For Bridge Deck Surfaces


tive covering shall be repaired or replaced by the Con-tractor at own expense.

Care shall be taken to confine all materials to the areasto be waterproofed or dampproofed and to prevent disfig-urement of any other parts of the structure by dripping orspreading of the primer or asphalt.

21.4.1 Asphalt Membrane Waterproofing

21.4.1.1 General

Asphalt membrane waterproofing shall consist of acoat of primer applied to the prepared surface and a firmlybonded membrane composed of two layers of saturatedfabric and three moppings of waterproofing asphalt and,when required, a protective cover.


Asphalt shall be heated to a temperature between 300and 350°F. The heating kettles shall be equipped withthermometers.

In all cases, the waterproofing shall begin at the lowpoint of the surface to be waterproofed, so that water willrun over and not against or along the laps.

The first strip of fabric shall be of half-width; the sec-ond shall be full-width, lapped the full-width of the firstsheet; and the third and each succeeding strip shall be full-width and lapped so that there will be two layers of fabricat all points with laps not less than 2 inches wide. All endlaps shall be at least 12 inches.

Beginning at the low point of the surface to be water-proofed, a coating of primer shall be applied and allowedto dry before the first coat of asphalt is applied. The wa-terproofing shall then be applied as follows.

Beginning at the low point of the surface to be water-proofed, a section about 20 inches wide and the full lengthof the surface shall be mopped with the hot asphalt, andthere shall be rolled into it, immediately following themopping, the first strip of fabric, of half-width, whichshall be carefully pressed into place so as to eliminate allair bubbles and obtain close conformity with the surface.This strip and an adjacent section of the surface of a widthequal to slightly more than half of the width of the fabricbeing used shall then be mopped with hot asphalt, and afull width of the fabric shall be rolled into this, completelycovering the first strip, and pressed into place as before.This second strip and an adjacent section of the concretesurface shall then be mopped with hot asphalt and thethird strip of fabric “shingled” on so as to lap the first stripnot less than 2 inches. This process shall be continuedwith each strip of fabric lapping at least 2 inches over thesecond previous strip so that the entire surface is covered

with at least two layers of fabric. The entire surface shallthen be given a final mopping of hot asphalt.

The completed waterproofing shall be a firmly bondedmembrane composed of two layers of fabric and threemoppings of asphalt, together with a coating of primer.Under no circumstances shall one layer of fabric touch an-other layer at any point or touch the surface, as there mustbe at least three complete moppings of asphalt.

In all cases the mopping on concrete shall cover thesurface so that no gray spots appear, and on cloth it shallbe sufficiently heavy to completely conceal the weave. Onhorizontal surfaces not less than 12 gallons of asphaltshall be used for each 100 square feet of finished work,and on vertical surfaces not less than 15 gallons shall beused. The work shall be so regulated that, at the close of aday’s work, all cloth that is laid shall have received thefinal mopping of asphalt. Special care shall be taken at alllaps to see that they are thoroughly sealed down.

21.4.1.3 Special Details

At the edges of the membrane and at any points whereit is punctured by such appurtenances as drains or pipes,suitable provisions shall be made to prevent water fromgetting between the waterproofing and the waterproofedsurface.

All flashing at curbs and against girders, spandrelwalls, etc., shall be done with separate sheets lapping themain membrane not less than 12 inches. Flashing shall beclosely sealed either with a metal counter-flashing or byembedding the upper edges of the flashing in a groovepoured full of joint filler.

Joints which are essentially open joints but which arenot designed to provide for expansion shall first becaulked with oakum and lead wool or other material ap-proved by the Engineer, and then filled with hot joint filler.

Expansion joints, both horizontal and vertical, shall beprovided with sheet copper or lead in “U” or “V” form inaccordance with the details. After the membrane has beenplaced, the joint shall be filled with hot joint filler. Themembrane shall be carried continuously across all expan-sion joints.

At the ends of the structure the membrane shall be car-ried well down on the abutments and suitable provisionmade for all movement.

21.4.1.4 Damage Patching

Care shall be taken to prevent injury to the finishedmembrane by the passage over it of workpersons or equip-ment, or by throwing any material on it. Any damagewhich may occur shall be repaired by patching. Patches



shall extend at least 12 inches beyond the outermost dam-aged portion and the second ply shall extend at least 3inches beyond the first.

21.4.2 Preformed Membrane WaterproofingSystems

21.4.2.1 General

Preformed membrane waterproofing systems shallconsist of a primer applied to the prepared surface, a sin-gle layer of adhering preformed membrane sheet and,when required, a protective cover.

21.4.2.2 Installation on Bridge Decks

Prior to applying the primer, an oil resistant construc-tion paper mask shall be taped or held with an adhesive toany deck areas which will later be covered by expansiondams or headers.

The membrane seal and asphalt concrete shall beplaced continuously across such paper masks; however,the mask and the preformed sheet shall be cut at or nearthe expansion joint when ordered by the Engineer.

The neoprene based primer shall be applied in one coatat a rate of approximately 300 square feet per gallon. Theresin or solvent based primer shall be applied, in one coat,at a rate of approximately 120 square feet per gallon.Primer shall be applied to the entire area to be sealed byspray or squeegee methods.

All primers shall be thoroughly mixed and continu-ously agitated during application.

Primers shall be allowed to dry to a tack free conditionbefore placing membrane sheets.

Should membrane sheets not be placed over sol-vent based primed surfaces within 24 hours, or neoprenebased primed surfaces within 36 hours, or resin basedprimed surfaces within 8 hours, the surfaces shall bereprimed.

The preformed membrane sheets shall be applied tothe primed surfaces either by hand methods or by me-chanical applicators. The membrane sheet shall be placedin such a manner that a shingling effect is achieved in thedirection that water will drain. First, a 12-inch minimumwidth membrane stripe shall be placed along the junctureof deck and base of barrier railing or curb face at the lowside of the deck with the sheet extending up the face 3inches. Next, starting at the gutter line, sheets shall belaid longitudinally and side lapped with adjacent sheetsby not less than 21⁄ 2 inches and end lapped by not less than6 inches. A 12-inch minimum width strip shall then beplaced at the juncture of deck and base of curb or railingat the high side of the deck extending up the face 3

inches. After being laid, the membrane sheets shall berolled with hand rollers or other apparatus as necessaryto develop a firm and uniform bond with the primed con-crete surfaces. Procedures shall be used which minimizewrinkles and air bubbles. Any tears, cuts, or narrow over-laps shall be patched, using a satisfactory adhesive andby placing sections of membrane sheet over the defectivearea in such a manner that the patch extends at least 6inches beyond the defect. On modified bitumen sheetswith a permanent polyester film, a propane torch shall beused to melt the polyester film on the section to bepatched. The patch shall then be placed over the heatedsurface. All patches shall be rolled or pressed firmly ontothe surface.

At all open joints, deck bleeder pipes and at other lo-cations when ordered by the Engineer, the membranesheet shall be cut and turned into the joint or bleeder asmembrane sheet is laid.

For rubberized asphalt sheets and modified bitumensheets, mastic shall be applied as a bead along the exposededge of the membrane sheet which extends up the barrierrailing or curb face, and which terminates in the high sidegutter after the sheets have been installed.

21.4.2.3 Installation on Other Surfaces

Installation of preformed membranes on surfaces otherthan bridge decks shall conform to the applicable require-ments for bridge decks and the following:

Preformed membrane material shall be placed verti-cally with each successive sheet lapped to the precedingby a minimum of 3 inches. Horizontal splices shall belapped by a minimum of 6 inches.

Exposed edges of membrane sheets shall have a trow-eled bead of manufacturer’s recommended mastic or seal-ing tape applied after the membrane is placed.

All projecting pipe, conduits, sleeves or other facilitiespassing through the preformed membrane waterproofingshall be flashed with prefabricated or field-fabricatedboots, fitted coverings or other devices as necessary toprovide watertight construction.

21.4.3 Protective Cover

Protective covers shall be installed sufficiently soonafter the application of waterproofing to prevent any dam-age to the waterproofing from exposure to sunlight or theweather or damage from traffic or subsequent construc-tion operations.

Hardboard protective covering shall be placed on acoating of adhesive of a type recommended by the water-proofing manufacturer. The adhesive shall be applied at a



rate sufficient to hold the protective covering in positionuntil the backfill is placed.

21.4.4 Dampproofing

Concrete, brick, or other surfaces that are to be pro-tected by dampproofing shall be thoroughly clean beforethe primer is applied. The surface to be dampproofed shallbe primed and then thoroughly mopped with waterproof-ing asphalt. When the first mopping of asphalt has set suf-ficiently, the entire surface shall be mopped with the sec-ond coating of hot asphalt. Special care shall be taken tosee that there are no skips in the coatings and that all sur-faces are thoroughly covered.


Waterproofing and dampproofing will be measured bythe square yard complete in place and accepted.

Payment will be made on the basis of the number ofsquare yards of waterproofing or dampproofing measured.

Payment for waterproofing includes full compensationfor the cost of furnishing all equipment, materials, andlabor necessary for the satisfactory completion of the wa-terproofing membrane and the protection cover.

Payment for dampproofing includes full compensationfor the cost of furnishing all equipment, materials, andlabor necessary for the satisfactory completion of thedampproofing.



Section 22SLOPE PROTECTION

22.1 GENERAL

22.1.1 Description

This work shall consist of the construction of bank andslope protection courses in accordance with these Speci-fications and in reasonably close conformity with thelines, grades, and thicknesses shown on the plans or es-tablished by the Engineer.

22.1.2 Types

Types of slope protection are designated as follows:

(1) Riprap

Hand-Placed Riprap—hand-placed stones on earthor gravel bedding.

Machine-Placed Riprap—machine-placed stones onearth or gravel bedding.

Wire-Enclosed Riprap (Gabions)—stones placed inwire fabric enclosures.

Grouted Riprap—hand-placed riprap as describedabove with voids filled with sand-cement grout.

Sacked Concrete Riprap—hand-placed sacked con-crete.

(2) Concrete Slope Paving

Cast-in-Place Slope Paving—Portland cement con-crete, pneumatically applied mortar or, when per-mitted, fabric forms filled with structural concretegrout.

(3) Precast Concrete Slope Paving—Portland cementconcrete slabs, blocks, or shapes precast prior to place-ment.


Whenever specified or requested by the Engineer, theContractor shall provide working drawings with designcalculations and supporting data in sufficient detail to per-mit a structural review of the proposed design of a slopeprotection system. When concrete is involved, such data

shall include the sequence and rate of placement. Suffi-cient copies shall be furnished to meet the needs of the En-gineer and other entities with review authority. The work-ing drawings shall be submitted sufficiently in advance ofproposed use to allow for their review, revision, if needed,and approval without delay to the work.

The Contractor shall not start the construction of anyslope protection system for which working drawings arerequired until the drawings have been approved by the En-gineer. Such approval will not relieve the Contractor of re-sponsibility for results obtained by use of these drawingsor any other responsibilities under the contract.

22.3 MATERIALS

22.3.1 Aggregate

Aggregate for riprap shall conform to the requirementsof Subsection 703.16 of the AASHTO Guide Specifica-tions for Highway Construction.

Aggregate for underdrains and filter blankets shall conform to Sections 704 and 705, respectively, of theAASHTO Guide Specifications for Highway Construction.

22.3.2 Wire-Enclosed Riprap (Gabions)

Gabions shall be constructed of wire mesh. The wiremesh shall be made of galvanized steel wire having a min-imum size of 0.120-inch diameter (U.S. Wire Gage No.11). The tensile strength of the wire shall be in the rangeof 60,000 to 85,000 psi, determined in accordance withASTM A 392. The minimum zinc coating of the wire shallbe 0.80 oz/sq ft of uncoated wire surface as determined inaccordance with ASTM A 90.

Selvedge, tie, and connection wire shall meet the samestrength and coating requirements specified above forwire used in the wire mesh.

22.3.3 Filter Fabric

Filter fabric shall meet the requirements of Subsection705.03 of the AASHTO Guide Specifications for HighwayConstruction.

645


22.3.4 Grout

Grout shall consist of one part Portland cement andthree parts of sand, thoroughly mixed with water to pro-duce a workable mix.

22.3.5 Sacked Concrete Riprap

Concrete for sacked concrete riprap shall consist of amixture of clean pitrun or washed sand and gravel, cementand water. The mixture shall contain not less than 376pounds of Portland cement per cubic yard and sufficientwater to obtain a slump of 3 to 5 inches. Sacks for sackedconcrete riprap shall be made of 10-ounce burlap or otherfabric having equal or greater strength. Sacks shall beapproximately 191⁄2 inches by 36 inches measured insidethe seams when the sack is laid flat, with an approximatecapacity of 1.25 cubic feet. Sound, reclaimed sacks may beused.

22.3.6 Portland Cement Concrete

Portland cement concrete for cast-in-place slopepaving shall conform to the provisions in Section 8, “Con-crete Structures,” for Class B or Class B (AE) concreteusing the 1-inch maximum combined grading.

Expansion joint filler shall conform to the provisionsin Article 8.9.2.1.

22.3.7 Pneumatically Applied Mortar

Materials for pneumatically applied mortar shall con-form to the requirements of Section 24, “PneumaticallyApplied Mortar.”

22.3.8 Precast Portland Cement Concrete Blocksand Shapes

Precast Portland cement concrete blocks and shapesshall meet the requirements of ASTM C 129, C 139, or C145, grade as specified. Materials for precast Portland ce-ment concrete slabs shall conform to the requirements inArticle 8.13, “Precast Concrete Members.”


Reinforcement shall conform to the provisions in Sec-tion 9, “Reinforcing Steel.”

22.3.10 Geocomposite Drain

Geocomposite drain shall consist of a manufacturedcore with one or both sides covered with a layer of filterfabric.

The manufactured core shall be a preformed grid ofembossed plastic, a mat of random shapes of plastic fibers,a drainage net consisting of a uniform pattern of poly-meric strands forming two sets of continuous flow chan-nels, a system of plastic pillars and interconnections form-ing a semi-rigid mat, or other system approved by theEngineer, which will conduct the flow of water designatedon the plans or in the special provisions.

Filter fabric shall conform to the requirements of Arti-cle 22.3.3 and shall be integrally bonded to the core ma-terial.

The Contractor shall furnish to the Engineer a signedcertification from the manufacturer stating that thegeocomposite drain proposed for use is capable ofwithstanding design loadings at all planned locationswithout appreciably decreasing the carrying capacity ofthe designed drainage voids for the entire height or lengthof the drain.

22.4 CONSTRUCTION

22.4.1 Preparation of Slopes

Slopes shall be shaped to allow the full thickness of the specified slope protection and any bedding or filtergravel, where required. Slopes shall not be steeper thanthe natural angle of repose of the slope specified in the contract. Where the slopes cannot be excavated toundisturbed material, the underlying material shall be compacted to 95% standard density per AASHTO T 99.

22.4.2 Bedding

When called for on the plans, a layer of filter gravel orfilter fabric shall be placed on the slope immediately priorto placement of the riprap or slope paving. The layer of fil-ter gravel shall be shaped to provide the minimum thick-ness specified.

22.4.3 Filter Fabric

When specified in the contract, filter fabric shall bespread uniformly over the prepared slope or surface. Thefabric shall be unrolled directly on the surface to the linesand dimensions shown. The filter fabric shall be lapped aminimum of 12 inches in each direction and shall be an-chored in position with approved anchoring devices. TheContractor shall place the riprap in a manner that will nottear, puncture, or shift the fabric. Tracked or wheeledequipment will not be permitted on the fabric coveredslopes.



22.4.4 Geocomposite Drain

Geocomposite drains shall be installed at locationsshown on the plans, described in the special provisions,and where directed by the Engineer. Collection and dis-charge systems shall be installed as shown on the plans oras directed by the Engineer.

Core material manufactured from impermeable plasticsheeting having connecting corrugations shall be placedwith the corrugations approximately perpendicular to thedrainage collection system.

When only one side of the geocomposite drain is cov-ered with filter fabric, the drain shall be installed with thefilter fabric side facing the embankment. The fabric fac-ing the embankment side shall overlap a minimum of 3inches at all joints and wrap around the exterior edges aminimum of 3 inches beyond the exterior edge. If addi-tional fabric is needed to provide overlap at joints andwrap-around at edges, the added fabric shall overlap thefabric on the geocomposite drain at least 6 inches and beattached thereto.

Should the fabric on the geocomposite drain be torn orpunctured, the damaged section shall be replaced com-pletely or repaired by placing a piece of fabric that is largeenough to cover the damaged area and provide a 6-inchoverlap all around the damaged area.

22.4.5 Hand Placing Stones

Where hand placing of stones is specified, the largerstones shall be placed first with close joints. The largerstones shall be placed in the footing trench. Stones shallbe placed with their longitudinal axis normal to the em-bankment face and arranged so that each stone above thefoundation course has a three-point bearing on the under-lying stones. The foundation course is the course placedon the slope in contact with the ground surface. Bearingon smaller stones that may be used for chinking voids willnot be acceptable. Placing of stones by dumping will notbe permitted. Interstices shall be filled with smaller stonesand spalls.

22.4.6 Machine-Placed Stones

22.4.6.1 Dry Placement

Machine-placed stones shall be so placed so as to pro-vide a minimum of voids, and the larger stones shall beplaced in the toe course and on the outside surface of theslope protection. The stone may be placed by dumpingand may be spread in layers by bulldozers or other suit-able equipment. At the completion of slope protection

work, the footing trench shall be filled with excavated ma-terial, and compaction will not be required.

22.4.6.2 Underwater Placement

When placed under water, free dumping will not bepermitted without written permission of the Engineer.Placement shall be by controlled methods using bottomdump buckets or wire rope baskets lowered through thewater to the point of placement.

22.4.7 Wire-Enclosed Riprap (Gabions)

22.4.7.1 Fabrication

The wire mesh shall be twisted to form hexagonalopenings of uniform size. The maximum linear dimensionof the mesh opening shall not exceed 41⁄2 inches and thearea of the mesh opening shall not exceed 8 square inches.The mesh shall be fabricated in such a manner as to benonravelling. Nonravelling is defined as the ability to re-sist pulling apart at any of the twists or connections form-ing the mesh when a single wire strand in a section is cut.

Gabions shall be fabricated so the sides, ends, lid, anddiaphragms can be assembled at the construction site intorectangular baskets of the specified size. Gabions shall beof single unit construction—base, lid, ends, and sidesshall be either woven into a single unit or one edge ofthese members connected to the base section of the gabionin a manner that strength and flexibility at the point ofconnection is at least equal to that of the mesh.

Where the length of the gabion exceeds its horizontalwidth, the gabion shall be equally divided by diaphragmsof the same mesh and gauge as the body of the gabions,into cells the length of which does not exceed the hori-zontal width. The gabion shall be furnished with the nec-essary diaphragms secured in proper position on the basein a manner that no additional tying at this junction willbe necessary.

All perimeter edges of the mesh forming the gabionshall be securely clip bound or selvedged so that the jointsformed by tying the selvedges have at least the samestrength as the body of the mesh.

Selvedge wire used through all the edges (perimeterwire) shall not be less than 0.148-inch diameter (U.S.Wire Gage No. 9) and shall meet the same strength andcoating specifications as the wire mesh.

Tie and connection wire shall be supplied in sufficientquantity to securely fasten all edges of the gabion and di-aphragms and to provide for at least four cross connectingwires in each cell whose height is equal to the width andat least two cross-connecting wires in each cell whoseheight is one-half the width of the gabion. Cross-connect-



ing wires will not be required when the height of the cellis one-third the width of the gabion. Tie and connectionwire shall meet the same strength and coating specifica-tions as the wire used in the mesh, except that it may beas much as two gages smaller.

In lieu of tie wire, two gauge galvanized hog rings maybe used to connect adjacent baskets and to secure basketlids. Spacing of the hog rings shall not exceed 6 inches.

Vertical joints in the completed work shall be staggeredat approximately 1⁄ 3 or 1⁄ 2 the length of the full baskets.


The gabions shall be placed on a smooth foundation.Final line and grade shall be approved by the Engineer.

Each gabion unit shall be assembled by binding to-gether all vertical edges with wire ties on approximately6-inch spacing or by a continuous piece of connectingwire stitched around the vertical edges with a coil aboutevery 4 inches. Empty gabion units shall be set to line andgrade as shown on the plans or as directed by the Engi-neer. Wire ties, hog rings, or connecting wire shall beused to join the units together in the same manner as de-scribed above for assembling. Internal tie wires shall beuniformly spaced and securely fastened in each cell of thestructure.

A standard fence stretcher, chain fall, or iron rod maybe used to stretch the wire baskets and hold alignment.

The gabions shall be filled with stone carefully placedby hand or machine to assure alignment and avoid bulgeswith a minimum of voids. Alternate placing of rock andconnection wires shall be performed until the gabion isfilled. After a gabion has been filled, the lid shall be bentover until it meets the sides and edges. The lid shall thenbe secured to the sides, ends and diaphragms with the wireties or connecting wire in the manner described above forassembling.

22.4.8 Grouted Riprap

Stones shall be placed on the slope as specified in Ar-ticle 22.4.5 and shall be thoroughly moistened with waterafter placement. Grout shall be applied while the stone ismoist and shall be worked into the interstices to com-pletely fill the voids.

Where the depth is in excess of 12 inches, the stoneshall be placed in 12-inch lifts and each lift grouted priorto placement of the next lift. Succeeding lifts shall beconstructed and grouted before grout in the previous lifthas set.

Grout shall be placed only when the weather is suitableand shall be protected from freezing for at least 4 days.The surface shall be cured by covering with moist earth,

wet rugs or curing blankets for at least 3 days after groutplacement.

Weep holes shall be provided through the riprap asshown on the plans or as directed by the Engineer.

22.4.9 Sacked Concrete Riprap

Sacks shall be filled with approximately 1 cubic foot ofconcrete, leaving room at the top to fold the sacks and re-tain the concrete during placement. Immediately afterbeing filled, the sacks shall be placed and lightly trampledto conform with the earth face and with adjacent sacks.

The first two courses shall provide a foundation of dou-ble thickness. The first foundation course shall consist ofa double row of stretchers (long dimension of sack paral-lel to contour of slope) laid level and adjacent to eachother in a neatly trimmed trench. The trench shall be lo-cated as shown on the plans, or as directed by the Engi-neer, cut to the proper depth and width to accommodateplacement of the first two foundation courses, and cutback into the slope a sufficient distance to enable propersubsequent placement of the riprap. The second founda-tion course shall consist of a row of headers (long dimen-sion at right angles to the stretchers) placed directly abovethe double row of stretchers. The remaining courses shallconsist of stretchers and shall be placed with staggeredjoints.

Dirt and debris shall be removed from the top of thesacks before the next course is placed. Stretchers shall beplaced so that the folded ends are not adjacent. Headersshall be placed with the folds toward the earth face. Notmore than four vertical courses of sacks shall be placed inany tier until initial set has taken place in the first course.

When there will not be proper bearing or bond for theconcrete because of delays in placing succeeding layers ofsacks, a small trench shall be excavated back of the rowof sacks and filled with fresh concrete before the nextlayer of sacks is laid. Header courses may be required atany level to provide additional stability.

Sacked concrete riprap shall be cured with a blanket ofwet earth or by sprinkling with a fine spray of water every2 hours during the daytime for 4 days.

Weep holes shall be provided through the riprap asshown on the plans or as directed by the Engineer.

22.4.10 Concrete Slope Paving

22.4.10.1 General

This work shall consist of constructing cast-in-placeand precast portland cement concrete slope paving. At theoption of the Contractor, the cast-in-place slope pavingshall be constructed of either Portland cement concrete or



pneumatically applied mortar. Where specified or permit-ted by the Engineer, this work shall also include wovenfabric forms filled with fine aggregate Portland cementconcrete grout.

22.4.10.2 Cast-in-Place Slope Paving

Concrete shall be mixed and placed in conformancewith the provisions in Section 8, “Concrete Structures,”and shall be spread and tamped until it is thoroughly com-pacted and mortar flushes to the surface. If the slope is toosteep to permit the use of concrete sufficiently wet to flushwith tamping, the concrete shall be tamped until consoli-dated and a mortar surface 1⁄ 4-inch thick, troweled on im-mediately. The mortar shall consist of one part Portlandcement and three parts of fine aggregate. The mortar sur-face shall be considered as a part of the concrete and noseparate payment will be made therefore.

After striking off to grade, the concrete shall be handfloated with wooden floats. The entire surface shall bebroomed with a fine texture hair push broom to produce auniform surface with the broom marks parallel to theedges of the panel. Edges and joints shall be edged with a1⁄ 4-inch radius edger prior to the brooming.

Pneumatically applied mortar shall be placed and fin-ished in accordance with the provisions in Section 24,“Pneumatically Applied Mortar.”

Expansion joints shall be installed transversely at in-tervals of 20 feet. Longitudinal expansion joints shall beinstalled at the locations shown on the plans. Expansionjoints shall be filled with expansion joint filler 1⁄ 2-inchthick.

Cast-in-place concrete and pneumatically appliedmortar shall be cured as provided in Sections 8 and 24, re-spectively.

Weep holes shall be provided through the slope pavingas shown on the plans or as directed by the Engineer.

When permitted or specified, the Contractor may usewoven fabric forms filled with pumpable fine aggregatePortland cement concrete grout as the slope protectionsystem. The request by the Contractor to use a particularsystem must be in writing accompanied by working draw-ings and complete information as to the materials, con-struction and performance characteristics of the proposedsystem.

Pervious backfill material, if required by the plans,shall be placed as shown. Two cubic feet of pervious back-fill material wrapped in filter fabric shall be placed at eachweep hole and drain hole.

At the completion of the work, footing trenches shallbe filled with excavated material and compaction will notbe required.

22.4.10.3 Precast Slope Paving

Precast slabs, blocks, and shapes shall be laid on a 3-inch bed of cushion sand in the pattern shown on theplans. Blocks and shapes shall be thoroughly rammed inplace to provide a uniformly even surface and solid bed-ding under each block or shape.

In the areas where grouting is called for, the blocksshall be laid in running bond with the length parallel to the slope and with 1⁄ 4-inch joints. Following the layingof the blocks, in the area to be grouted, sufficient mortar sand shall be spread over the surface and swept into the joints to fill the latter to 4 inches from the surface. The blocks shall be wetted to the satisfac-tion of the Engineer before any grout is placed. The joints shall be filled with grout flush with the top of theblock.

After grouting has been completed and the grout hassufficiently hardened, the blocks shall be wetted, coveredand cured with curing blankets or covers for the first 7days after grouting. Grout shall not be poured duringfreezing weather.



22.5.1.1 Stone Riprap and Filter Blanket

Hand-placed riprap, machine-placed riprap, groutedriprap, and filter blanket aggregate will be measured bythe square yard, cubic yard, or ton, as listed in the sched-ule of bid items. The area will be that actually placed tothe limiting dimensions shown on the plans, or the plan di-mensions as may have been revised by the Engineer, mea-sured along the upper surface. If measured by the cubicyard, the volume will be computed on the basis of themeasured area and the thickness specified on the plans. Ifmeasured by the ton, the quantity shall be the number oftons, loose measure, incorporated into the work.

22.5.1.2 Sacked Concrete Riprap

Sacked concrete riprap will be measured by the cubicyard of concrete placed. Measurement will be based onmixer volumes.

22.5.1.3 Wire-Enclosed Riprap (Gabions)

Wire-enclosed riprap (gabions) will be measured as thenumber of square yards of surface area.



22.5.1.4 Cast-in-Place Concrete Slope Paving

Cast-in-place concrete or pneumatically applied mor-tar slope paving will be measured on a square yard orcubic yard basis. The area will be that actually placed tothe limiting dimensions shown on the plans, or the plandimensions as may have been revised by the Engineer,measured along the upper sloped surface. If measured bythe cubic yard, the volume will be computed on the basisof the measured area and the thickness shown on theplans. No additional compensation will be allowed for ad-ditional concrete or pneumatically applied mortar placedby reason of low foundation.

22.5.1.5 Precast Concrete Slope Paving

Precast concrete slabs, blocks, or shapes placed asslope paving will be measured in square yards computedfrom the payment lines shown on the plans, or as directedby the Engineer.

22.5.1.6 Filter Fabric

Filter fabric will be measured by the square yard on theground surface, excluding overlaps, complete in place.

22.5.2 Payment

22.5.2.1 General

Payment for slope protection of the various classes atthe unit prices bid will include full compensation for alllabor, materials, equipment, or other incidentals in con-nection with the preparation of subgrade (except for thefurnishing and placement of filter blanket material and fil-ter fabric), excavating and backfilling toe trenches whererequired, furnishing and placing the stones, slabs, blocks,shapes, grout, mortar, Portland cement concrete, pneu-matically applied mortar, reinforcing steel, expansionjoint filler, if required, and all other work and incidentalmaterial required to complete the work in accordance withthe plans and specifications.

22.5.2.2 Stone Riprap

Hand-placed riprap, machine-placed riprap, andgrouted riprap measured in accordance with Article22.5.1.1 will be paid for at the price bid per square yard,per cubic yard, or per ton as set forth in the schedule ofbid items.

22.5.2.3 Sacked Concrete Riprap

Sacked concrete riprap measured in accordance with Art-icle 22.5.1.2 will be paid for at the price bid per cubic yard.

22.5.2.4 Wire-Enclosed Riprap (Gabions)

Wire-enclosed riprap (gabions) measured in accor-dance with Article 22.5.1.3 will be paid for at the price bidper square yard. Such price shall include wire baskets, con-nection hardware, anchors, aggregate filling, and any othermaterials, labor, and equipment necessary to complete thework in accordance with the plans and specifications.

22.5.2.5 Cast-in-Place Concrete Slope Paving

Cast-in-place concrete or pneumatically appliedmortar slope paving measured in accordance with Art-icle 22.5.1.4 will be paid for at the price bid per squareyard or per cubic yard as set forth in the schedule of biditems.

22.5.2.6 Precast Concrete Slope Paving

Precast concrete slope paving measured in accordancewith Article 22.5.1.5 will be paid for at the price bid persquare yard. Such price shall include cushion sand andshall include Portland cement grout or mortar, if requiredby the plans or specifications.

22.5.2.7 Filter Blanket

Filter blanket or filter gravel measured in accordancewith Article 22.5.1.1 will be paid for at the price bid persquare yard, per cubic yard, or per ton as set forth in theschedule of bid items.

22.5.2.8 Filter Fabric

Filter fabric measured in accordance with Art-icle 22.5.1.6 will be paid for at the price bid per squareyard.

22.5.2.9 Geocomposite Drain System

Geocomposite drain system will be paid for on thebasis of a contract lump sum price. Such lump sum priceshall include full compensation for furnishing all labor,materials, tools, equipment, and incidentals, and for doingall the work involved in constructing geocomposite drainsystems complete in place including geocomposite drain,collection and discharge systems as shown on the plans,as specified in the special provisions and as directed by theEngineer.



Section 23MISCELLANEOUS METAL

23.1 DESCRIPTION

This work shall consist of furnishing and installingmetal items in structures which are not otherwise pro-vided for. Such work includes but is not limited to the fol-lowing items:

(1) Expansion joint armor in bridge decks, and slidingplate and finger type expansion joints.(2) Manhole frames and covers, drainage pipes,frames and grates, ladders or ladder rungs, accessopening covers, and access door assemblies.(3) Other items specifically identified as miscella-neous metal on the plans or in the specifications.

23.2 MATERIALS

Miscellaneous metal items shall be constructed of ma-terials conforming to the following AASHTO (or ASTM)material specifications:

23.3 FABRICATION

Fabrication of miscellaneous metal items shall be per-formed in a workmanlike manner in conformance with the

practice in modern commercial shops. Burrs, rough andsharp edges, and other flaws shall be removed. Warpedpieces shall be straightened after fabrication and galva-nizing.

23.4 GALVANIZING

Unless otherwise specified all steel items, which arenot embedded at least 2 inches in concrete, and all castiron sidewalk frames and covers shall be galvanized in ac-cordance with Articles 11.3.2.4 and 11.3.7 of Section 11,“Steel Structures.” Assemblies shall be galvanized afterfabrication.

23.5 MEASUREMENT

Measurement of miscellaneous metal shall be by the scale weight. When requested by the Engineer, each delivery shall be accompanied with a certifiedweighmaster’s weight ticket. Scale weights are not re-quired when calculated weights are shown on the plans, inwhich case these weights shall be used as the basis ofpayment.

23.6 PAYMENT

Miscellaneous metal will be paid for by the contractunit price per pound. Such payment shall include fullcompensation for furnishing all labor, materials, tools,equipment and incidentals, and for doing all the work in-volved in furnishing and installing miscellaneous metal,complete in place, as shown on the plans, and as specifiedin these specifications and the special provisions, and asdirected by the Engineer.

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Section 24PNEUMATICALLY APPLIED MORTAR

24.1 DESCRIPTION

This work shall consist of the furnishing and placing of pneumatically applied mortar for the construction ofportions of structures, repairing concrete structures,texturing concrete surfaces, encasement of structural steel members, lining ditches and channels, paving slopesand for other miscellaneous work, all as shown on theplans.

This work also includes the preparation of surfaces toreceive the mortar and the furnishing and placing of anyreinforcing steel and anchors for reinforcement.

Pneumatically applied mortar shall consist of eitherdry mixed fine aggregate and Portland cement pneumati-cally applied by a suitable mechanism, to which mixturethe water is added immediately previous to its expulsionfrom the nozzle, or mortar premixed by mechanical meth-ods and pneumatically applied through a nozzle onto theprepared surface.

24.2 MATERIALS

24.2.1 Cement, Aggregate, Water and Admixtures

Cement, aggregate, water and admixtures, when used,shall conform to the requirements of Section 8, “ConcreteStructures.” Aggregate shall be fine aggregate, except thatup to 30% coarse aggregate, conforming to AASHTO M43 for size 3⁄ 8 inch to No. 8 or No. 16, may be substitutedfor fine aggregate.

Recovered rebound which is clean and free of foreignmaterial may be reused as fine aggregate in quantitiesnot to exceed 20% of the total fine aggregate require-ments.



24.2.3 Anchor Bolts or Studs

Anchor studs used to support reinforcing wire fabric orbars when placing mortar against existing concrete orrock shall consist of 1⁄ 4-inch minimum diameter expansionhook bolts placed in drilled holes. Each bolt shall havesufficient engagement in sound masonry to resist a pull-out force of 150 lbs.

When permitted by the Engineer, driven steel studs ofnot less than 1⁄ 8-inch diameter and a minimum length of 2inches may be used. The equipment used for driving suchstuds shall be of the type which uses an explosive for thedriving force, and shall be capable of inserting the stud orpin to the required depth without damage to the surround-ing concrete.

24.3 PROPORTIONING AND MIXING

24.3.1 Proportioning

The Contractor shall submit the proposed mix designto the Engineer for approval prior to start of the work.

Unless otherwise specified, the mix design shall pro-vide a cement to aggregate ratio, based on dry loose vol-umes, of not less than 1:3.5 for the construction and repairof concrete structures and for encasing steel members, ornot less than 1:5 for lining ditches and channels and forpaving slopes.

The water content shall be as low as practical and shallbe adjusted so that the mix is sufficiently wet to adhereproperly and sufficiently dry so that it will not sag or fallfrom vertical or inclined surfaces or separate in horizon-tal work.

24.3.2 Mixing

Mixing shall be done either by the dry mix or wet mixprocess. Before being charged into the placing equipment,the materials shall be thoroughly and uniformly mixedusing a mixer designed for use with pneumatic applica-tion. It may be either a paddle type or drum type mixer.Transit mix equipment and methods may be used for thewet process.

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24.4 SURFACE PREPARATION

24.4.1 Earth

When pneumatically applied mortar is to be placedagainst earth, the area shall be accurately graded to theplan dimensions and shall be thoroughly compacted, withsufficient moisture to provide a firm foundation and toprevent absorption of water from the mortar, but shall notcontain free surface water.

When shown on the plans, joints, side forms, headersand shooting strips shall be provided for backing or pan-eling. Ground or gaging wires shall be used where neces-sary to establish thicknesses, surface planes, and finishlines.

24.4.2 Forms

When mortar is to be placed against forms, the formsshall conform to the requirement of Section 3, “Tempo-rary Works.”

24.4.3 Concrete or Rock

When mortar is to be placed against concrete or rock,all deteriorated or loose material shall be removed bychipping with pneumatic or hand tools. Square or slightlyundercut shoulders shall be cut approximately 1-inch deepalong the perimeter of repair areas. The surface shall besandblasted as necessary to clean all rust from exposedsteel and to produce a clean rough-textured surface on theconcrete or rock. The surface against which mortar is tobe placed shall be kept wet for at least 1 hour and then al-lowed to dry to a surface dry condition just prior toapplication of the mortar.

24.5 INSTALLATION

24.5.1 Placement of Reinforcing

Reinforcing steel, when required, shall be installed inconformance with the requirements of Section 9, “Rein-forcing Steel.”

Reinforcement in new construction shall be placed asspecified in the plans and secured to insure no displace-ment from impact of the pneumatically placed mortar dur-ing application.

For repair work, the reinforcing steel shall be sup-ported by anchor studs installed in the existing masonryexcept where existing reinforcing steel in the repair areais considered by the Engineer to be satisfactory for thispurpose. Anchors shall be spaced no more than 12 inches,

center to center, on overhead surfaces; 18 inches, center tocenter, on vertical surfaces; and 36 inches, center to cen-ter, on top horizontal surfaces. At least three anchors shallbe used in each individual patch area.

The Engineer shall be notified in advance of the datewhen installation of anchor studs is to begin. The loca-tions of the studs shall be such that damage will not occurto prestressing tendons or conduits embedded in the con-crete.

Unless otherwise shown or specified, for repair work,all areas where the thickness of the mortar exceeds 11⁄ 2

inches shall be reinforced with a single layer of either 2 �2 � W1 � W1 or 3 � 3 � W1.5 � W1.5 welded wire fab-ric. For areas where the thickness of the mortar exceeds 4inches, a single layer of wire fabric shall be used to rein-force each 4-inch thickness of patch or fractional partthereof. All fabric shall be placed parallel to the proposedfinished surface. Each layer of fabric shall be completelyencased in mortar which has taken its initial set, before thesucceeding layer of fabric is installed. Fabric supportedadjacent to the prepared masonry surface shall be nocloser than 1⁄ 2 inch to said surface. Fabric shall be carefullyprebent before installation to fit around corners and intore-entrant angles, and shall in no case be sprung intoplace.

All steel items, including anchors, reinforcing bars andwire fabric, shall be no closer than 1 inch to the finishedsurface of the mortar.

24.5.2 Placement of Mortar

Only experienced foremen, gunmen, nozzlemen, androdmen shall be employed, and satisfactory evidence ofsuch experience shall be furnished when requested by theEngineer.

The mortar shall be applied by pneumatic equipmentthat sprays the mix onto the prepared surface at a highvelocity as needed to produce a compacted dense homo-geneous mass. The air compressor and delivery hose linesshall be of adequate capacity and size to provide a mini-mum pressure of 35 psi at the nozzle for 1-inch nozzlesand proportionally greater for larger nozzles. The veloc-ity of the material as it leaves the nozzle must be main-tained uniform at a rate determined for the given job con-ditions to produce minimum rebound.

Water which is added at the nozzle shall be supplied ata uniform pressure of not less than 15 psi greater than theair pressure at the nozzle.

The mortar shall be applied as dry as practicable to pre-vent shrinkage cracking. Shooting strips shall be em-ployed to insure square corners, straight lines, and a planesurface of mortar, except as otherwise permitted by theplans or approved by the Engineer. They shall be so placed



as to keep the trapping of rebound at a minimum. At theend of each day’s work, or similar stopping periods re-quiring construction joints, the mortar shall be sloped offto a thin edge. Before placing an adjacent section, con-struction joints shall be thoroughly cleaned and wetted asrequired under Article 24.4. In shooting all surfaces, thestream of flowing material from the nozzle shall impingeas nearly as possible at right angles to the surface beingcovered, and the nozzle shall be held from 2 to 4 feet fromthe working surface.

A sufficient number of mortar coats shall be applied toobtain the required thickness. On vertical and overheadsurfaces, the thickness of each coat shall be not greaterthan 1 inch, except as approved by the Engineer, and shallbe so placed that it will neither sag nor decrease the bondof the preceding coat. The time interval between succes-sive layers in sloping, vertical or overhanging work shallbe sufficient to allow initial but not final set to develop. Atthe time the initial set is developing, the surface shall becleaned to remove the thin film of laitance in order to pro-vide for a bond with succeeding applications.

Rebound or accumulated loose sand shall be removedfrom the surface to be covered prior to placing of the orig-inal or succeeding layers of mortar and shall not be em-bedded in the work.

Materials that have been mixed for more than 45 min-utes and have not been incorporated in the work shall notbe used, unless otherwise permitted by the Engineer.

After curing and before final acceptance, all repairedareas shall be sounded. All unsound and cracked areasshall be removed and replaced.

24.5.2.1 Weather Limitations

Pneumatically placed mortar shall not be placed on afrozen surface nor when the ambient temperature is lessthan 40°F; nor shall it be placed when it is anticipated thatthe temperature during the following 24 hours will dropbelow 32°F.

The application of pneumatically placed mortar shallbe suspended if high winds prevent proper application, orrain occurs which would wash out the pneumaticallyplaced mortar.

24.5.2.2 Protection of Adjacent Work

During progress of the work, where appearance is im-portant, adjacent facilities which may be permanently dis-

colored, stained, or otherwise damaged by overspray, dustor rebound, shall be adequately protected and, if con-tacted, shall be cleaned by early scraping, brushing, orwashing, as the surroundings permit.

24.5.3 Finishing

After mortar has been placed to desired thickness, allhigh spots shall be cut off with a sharp trowel, or screededto a true plane as determined by shooting strips or by the original masonry surface, or as directed. Cuttingscreeds, where used, shall be lightly applied to allsurfaces so as not to disturb the mortar for an appreciabledepth, and they shall be worked in an upward directionwhen applied on vertical surfaces. Unless otherwisedirected, the finished mortar surface shall be given a finalflash coat of about 1⁄ 8 inch of mortar. Special care shall betaken to obtain a uniform appearance on all exposedsurfaces.

24.5.4 Curing and Protecting

Pneumatically placed mortar shall be water cured inconformance with the requirements of Article 8.11.3.2.The minimum water curing duration shall be 96 hours.The mortar shall be protected from freezing during thecuring period.


The quantity of pneumatically applied mortar will bemeasured either by the square foot or by the cubic foot asindicated in the schedule of bid items.

Square foot measurements will be based on measure-ments of the surface area of acceptable mortar placed inthe work made along the plane or curve of each surface.Cubic foot measurement will be based on the dimensionsof such work shown in the plans or ordered by theEngineer.

Pneumatically applied mortar will be paid for by thecontract price per square foot or cubic yard. Such paymentshall be considered to be full compensation for the cost offurnishing all labor, materials, equipment, incidentals, andfor doing all work involved in preparing the surface andinstalling the mortar, reinforcing steel, anchor studs, head-ers, joint fillers, and other items as shown on the plans orspecified.



Section 25STEEL AND CONCRETE TUNNEL LINERS

25.1 SCOPE

These specifications are intended to cover the installa-tion of tunnel liner plates in tunnels constructed by con-ventional tunnel methods. For the purposes of these Spec-ifications, tunnels excavated by full face, heading andbench, or multiple drift procedures are considered con-ventional methods. Liner plates used with any construc-tion procedure utilizing a full or partial shield, a tunnelingmachine, or other piece of equipment which will exert aforce on the liner plates for the purpose of propelling,steering, or stabilizing the equipment are considered spe-cial cases and are not covered by these Specifications.

25.2 DESCRIPTION

25.2.1 This work shall consist of furnishing cold-formedsteel tunnel liner plates or precast concrete plates con-forming to these specifications and of the sizes and di-mensions required on the plans, and installing such platesat the locations designated on the plans by the Engineer,and in conformity with the lines and grades established bythe Engineer. The completed liner shall consist of a seriesof liner plates assembled with staggered longitudinaljoints.

Steel tunnel liner plates shall preferably be of a typewhich is commercially available. Precast concrete tunnelliner plates shall be such that their size and shape suits themethod and equipment being used to install them.

25.3 MATERIALS AND FABRICATION

Liner plates shall be fabricated to fit the cross sectionof the tunnel.

25.3.1 General

Steel liner plates herein described must meet the Sec-tional Properties of thickness, area, and moment of iner-tia shown on the plans. If not shown on the plans, theproperties shall be as listed in Division I, Article 16.3.

All steel plates shall be connected by bolts on both lon-gitudinal and circumferential seams or joints and shall beso fabricated as to permit complete erection from theinside of the tunnel. Bolt sizes and properties shall be inaccordance with the manufacturer’s standard but not lessthan those specified in Division 1, Article 16.7.

Grout holes 2 inches or larger in diameter shall beprovided as shown on the plans to permit grouting as theerection of tunnel liner plates progresses.

Precast concrete tunnel liner plates shall conform to thedetails shown on the plans and the requirements ofSection 8, “Concrete Structures.” If such details are notprovided and the plans or the specifications allow theContractor to propose the use of concrete liner plates, theContractor shall submit working drawings and specifica-tions to the Engineer for approval. Such drawings andspecifications shall describe materials to be used, platedimensions, reinforcement details, connecting details, anderection procedures. The fabrication of Contractorproposed types of concrete tunnel liner plates shall notbegin until the working drawings have been approved.Such approval shall not relieve the Contractor of anyresponsibility under the contract for the successfulcompletion of the work.

25.3.2 Forming and Punching of Steel Liner Plates

All plates shall be formed to provide circumferentialflanged joints. Longitudinal joints may be flanged or ofthe offset lap seam type. All plates shall be punched forbolting on both longitudinal and circumferential seams orjoints. Bolt spacing in circumferential flanges shall be inaccordance with the manufacturer’s standard spacing andshall be a multiple of the plate length so that plates hav-ing the same curvature shall be interchangeable and willpermit staggering of the longitudinal seams. Bolt spacingat flanged longitudinal seams shall be in accordance withthe manufacturer’s standard spacing. For lapped longi-tudinal seams, bolt size and spacing shall be in accordancewith the manufacturer’s standard but not less than thatrequired to meet the longitudinal seam strength require-ments of Division I, Article 16.3.2.

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25.4 INSTALLATION

25.4.1 Steel Liner Plates

All steel liner plates for the full length of a specifiedtunnel shall be of one type only, either the flanged or thelapped seam type of construction.

Liner plates shall be assembled in accordance with themanufacturer’s instruction.

Coated steel plates shall be handled in such a man-ner as to prevent bruising, scaling, or breaking of thecoating. Any plates that are damaged during handling or placing shall be replaced by the Contractor at ownexpense, except that small areas with minor damage may be repaired by the Contractor as directed by theEngineer.

25.4.2 Precast Concrete Liner Plates

Installation of precast concrete tunnel liner plates shallnot start prior to receipt of approval of working drawingsand specifications submitted as required by Article 25.3.1.Installation shall conform to the specified or approvederection procedures.

25.4.3 Grouting

When directed by the Engineer, voids occurring be-tween the liner plate and the tunnel wall shall be force-grouted. The grout shall be forced through the groutingholes in the plates with such pressure that all voids will becompletely filled. Full compensation for back packing orgrouting shall be considered as included in the contractprice paid for tunnel and no separate payment will bemade therefore.

25.5 MEASUREMENT

The length of tunnel liner to be paid for will be thelength measured along the tunnel liner plate invert.

25.6 PAYMENT

Payment for the length of each size of tunnel as deter-mined under measurement shall be at the contract unitprices per linear foot bid for the various sizes, which pay-ment shall include full compensation for furnishing alllabor, materials, tools, equipment, and incidentals to com-plete this item, including the force-grouting of voids.



Section 26METAL CULVERTS

26.1 GENERAL

26.1.1 Description

This work shall consist of furnishing, fabricating, andinstalling metal pipe, metal structural plate pipe, arches,pipe arches, and box structures in conformance with thesespecifications, the special provisions, and the detailsshown on the plans. As used in this specification, long-span structures are metal plate horizontal ellipse, invertedpear and multiple radius arch shapes as well as specialshape culverts as defined in Division I, Section 12, “Soil-Corrugated Metal Structure Interaction Systems.” Theterms “metal pipe” and “metal structural plate pipe” shallinclude both circular pipe arch, underpass and ellipticalshapes. “Metal structural plate arches” consist of a metalplate arch supported on reinforced concrete footings at itsbase (ends) with or without a paved invert slab. “Pipearches” are constructed to form a pipe having an arch-shaped crown and a relatively flat invert. “Metal structuralplate box structures” are conduits, rectangular in crosssection, constructed of metal plates.


Whenever specified or requested by the Engineer, theContractor shall provide manufacturer’s assembly in-structions or working drawings with supporting data insufficient detail to permit a structural review. Sufficientcopies shall be furnished to meet the needs of the Engi-neer and other entities with review authority. The workingdrawings shall be submitted sufficiently in advance ofproposed use to allow for their review, revision, if needed,and approval without delay to the work.

The Contractor shall not start the construction of anymetal culvert for which working drawings are requireduntil the drawings have been approved by the Engineer.Such approval will not relieve the Contractor of responsi-bility for results obtained by use of these drawings or anyof his or her other responsibilities under the contract.

26.3 MATERIALS

26.3.1 Corrugated Metal Pipe

Steel pipe shall conform to the requirements ofAASHTO M 36.

Aluminum pipe shall conform to the requirements ofAASHTO M 196.

26.3.2 Structural Plate

Steel structural plate shall conform to the requirementsof AASHTO M 167.

Aluminum alloy structural plate shall conform to therequirements of AASHTO M 219.

26.3.3 Nuts and Bolts

Nuts and bolts for steel structural plate pipe, arches,pipe arches, and box structures shall conform to the re-quirements of AASHTO M 167. Nuts and bolts for alu-minum structural plate shall be aluminum conforming toASTM F 468 or standard strength steel conforming toASTM A 307.

26.3.4 Mixing of Materials

Aluminum and steel materials shall not be mixed inany installation unless they are adequately separated orprotected to avoid galvanic reactions. Hot-dip galvanizingprovides such protection. Hot-dip galvanized steel andstainless steel bolts and nuts are acceptable for aluminumstructural plate.

26.3.5 Fabrication

Plates at longitudinal and circumferential seams shallbe connected by bolts with the seams staggered so that notmore than three plates come together at any one point.

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26.3.6 Welding

Welding of steel, if required, shall conform to theANSI/AASHTO/AWS Bridge Welding Code D1.5. Allwelding of steel plates, other than fittings, shall be per-formed prior to galvanizing.

Welding of aluminum, if required, shall conform to theAWS D1.2, “Structural Welding Code.”

26.3.7 Protective Coatings

When required by the plans or the special provisions,metal pipes and structural plate shall be protected with bi-tuminous coating or have the invert paved with bitumi-nous material. Bituminous coatings shall be applied asprovided in AASHTO M 190, Type A, unless otherwisespecified. Bituminous pavings, if required, shall be ap-plied over the bituminous coatings to the inside bottomportion of pipe as provided in AASHTO M 190, Type C,unless otherwise specified. The portion of all nuts andbolts used for assembly of coated structural plate project-ing outside the pipe, shall be coated after installation. Theportions of the nuts and bolts projecting inside the pipeneed not be coated.

Polymeric coatings, when called for on the plans or inthe special provisions, shall conform to the requirementsof AASHTO M 246. The polymeric coating shall be ap-plied to the galvanized sheet prior to corrugating and, un-less otherwise specified, the thickness shall be not lessthan 0.010 inch. Any pinholes, blisters, cracks, or lack ofbond shall be cause for rejection. Polymeric coatings willnot be permitted on structural plate pipes.

26.3.8 Bedding and Backfill Materials

26.3.8.1 General

Bedding material shall be loose native or granular ma-terial with a maximum particle (or clump) size not to ex-ceed one-half the corrugation depth. Backfill for metalculverts shall be granular material as specified in the plansand specifications and shall be free of organic material,stones larger than 3 inches in the greatest dimension,frozen lumps, or moisture in excess of that permittingthorough compaction. As a minimum, backfill materialsshall meet the requirements of AASHTO M 145 for A-1,A-2, or A-3.

26.3.8.2 Long-Span Structures

Bedding and backfill materials shall meet the generalrequirements of Article 26.3.8.1. As a minimum backfillmaterials for structures with less than 12 feet of cover shallmeet the requirements of AASHTO M 145 for A-1, A-2-4,

A-2-5, or A-3. Minimum backfill requirements for struc-tures with 12.0 feet or more cover shall meet AASHTO M145 requirements for A-1 or A-3.


Bedding and backfill materials shall meet the generalrequirements of Article 26.3.8.1. As a minimum, backfillshall meet the requirements of AASHTO M 145 for A-1,A-2-4, A-2-5, or A-3.

26.4 ASSEMBLY

26.4.1 General

Corrugated metal pipe and structural plate pipe shall beassembled in accordance with the manufacturer’s instruc-tions. All pipe shall be unloaded and handled with rea-sonable care. Pipe or plates shall not be rolled or draggedover gravel or rock and shall be prevented from strikingrock or other hard objects during placement in trench oron bedding.

Corrugated metal pipe shall be placed in the bed start-ing at the downstream end. Pipes with circumferentialseams shall be installed with their inside circumferentialsheet laps pointing downstream.

Bituminous coated pipe, polymer coated pipe, andpaved invert pipe shall be installed in a similar manner tocorrugated metal pipe with special care in handling toavoid damage to coatings. Paved invert pipe shall be in-stalled with the invert pavement placed and centered onthe bottom.

Structural plate shall be assembled and installed in ac-cordance with the plans and detailed erection instructions.Copies of the manufacturer’s assembly instructions shallbe furnished as specified in Article 26.2. Bolted longitu-dinal seams shall be well fitted with the lapping platesparallel to each other. The applied bolt torque for 3 ⁄4-inchdiameter high-strength steel bolts (A 449) for the assem-bly of steel structural plate shall be a minimum of 100 ft-lbs and a maximum of 300 ft-lbs. Aluminum structuralplate shall be assembled using 3⁄ 4-inch diameter aluminumbolts (F 468) or standard strength steel bolts (A 307)which shall be torqued to a minimum of 100 ft-lbs and amaximum of 150 ft-lbs. When seam sealant tape or a shopapplied asphalt coating is used, bolts should be retight-ened no more than once. Generally, retightening is donewithin 24 hours. There is no structural requirement forresidual torque; the important factor is the seam fit-up.

26.4.2 Joints

Joints for corrugated metal culvert and drainage pipeshall meet the following performance requirements.



26.4.2.1 Field Joints

Transverse field joints shall be of such design that thesuccessive connection of pipe sections will form a con-tinuous line free from appreciable irregularities in theflow line. In addition, the joints shall meet the general per-formance requirements described in Articles 26.4.2.2 and26.4.2.3. Suitable transverse field joints, which satisfy therequirements for one or more of the subsequently definedjoint performance categories can be obtained with the fol-lowing types of connecting bands furnished with the suit-able band-end fastening devices:

(a) Corrugated bands.(b) Bands with projections.(c) Flat bands.(d) Bands of special design that engage factory re-formed ends of corrugated pipe.(e) Other equally effective types of field joints may beused with the approval of the Engineer.

26.4.2.2 Joint Types

Applications may require either “Standard” or “Spe-cial” joints. Standard joints are for pipe not subject tolarge soil movements or disjointing forces; these joints aresatisfactory for ordinary installations, where simple sliptype joints are typically used. Special joints are for moreadverse requirements such as the need to withstand soilmovements or resist disjointing forces. Special designsmust be considered for unusual conditions as in poorfoundation conditions. Downdrain joints are required toresist longitudinal hydraulic forces. Examples of this aresteep slopes and sharp curves.

26.4.2.3 Soil Conditions

(a) The requirements of the joints are dependent on thesoil conditions at the construction site. Pipe backfill whichis not subject to piping action is classified as “nonerodi-ble.” Such backfill typically includes granular soil (withgrain sizes equivalent to coarse sand, small gravel, orlarger) and cohesive clays.

(b) Backfill that is subject to piping action, and wouldtend to either infiltrate the pipe or to be easily washed byexfiltration of water from the pipe, is classified as “Erodi-ble.” Such backfill typically includes fine sands and silts.

(c) Special joints are required when poor soil conditionsare encountered such as when the backfill or foundationmaterial is characterized by large soft spots or voids. Ifconstruction in such soil is unavoidable, this condition canonly be tolerated for relatively low fill heights, because thepipe must span the soft spots and support imposed loads.Backfills of organic silt, which are typically semi-fluid dur-ing installation, are included in this classification.

26.4.2.4 Joint Properties

The requirements for joint properties are divided intothe six categories given on Table 26.4. Properties are de-fined and requirements are given in the following para-graphs (a) through (f). The values for various types of pipecan be determined by a rational analysis or a suitable test.

(a) Shear Strength—The shear strength required of thejoint is expressed as a percent of the calculated shearstrength of the pipe on a transverse cross-section remotefrom the joint.

(b) Moment Strength—The moment strength requiredof the joint is expressed as a percent of the calculated mo-


TABLE 26.4 Categories of Pipe Joints


ment capacity of the pipe on a transverse cross section re-mote from the joint.

(c) Tensile Strength—Tensile strength is required in ajoint when the possibility exists that a longitudinal loadcould develop which would tend to separate adjacent pipesections.

(d) Joint Overlap—Standard joints which do not meetthe moment strength alternatively shall have a minimumsleeve width overlapping the abutting pipes. The mini-mum total sleeve width shall be as given in Table 26.4.Any joint meeting the requirements for a special joint maybe used in lieu of a standard joint.

(e) Soiltightness—Soiltightness refers to openings inthe joint through which soil may infiltrate. Soil tightnessis influenced by the size of the opening (maximum di-mension normal to the direction that the soil may infil-trate) and the length of the channel (length of the pathalong which the soil may infiltrate). No opening may ex-ceed 1 inch. In addition, for all categories, if the size ofthe opening exceeds 1⁄ 8 inch, the length of the channelmust be at least four times the size of the opening. Fur-thermore, for nonerodible or erodible soils, the ratio of D85

soil size to size of opening must be greater than 0.3 formedium to fine sand or 0.2 for uniform sand; these ratiosneed not be met for cohesive backfills where the plastic-ity index exceeds 12. As a general guideline, a backfillmaterial containing a high percentage of fine grained soilsrequires investigation for the specific type of joint to beused to guard against soil infiltration. Alternatively, if ajoint demonstrates its ability to pass a 2-psi hydrostatictest without leakage, it will be considered soil tight.

NOTE: Joints that do not meet these requirements maybe made soil tight by wrapping with a suitable geotextile.

(f) Watertightness—Watertightness may be specifiedfor joints of any category where needed to satisfy othercriteria. The leakage rate shall be measured with the pipein place or at an approved test facility. The adjoining pipeends in any joint shall not vary more than 0.5 inch in di-ameter or more than 1.5 inches in circumference for wa-tertight joints. These tolerances may be attained by properproduction controls or by match-marking pipe ends.

26.4.3 Assembly of Long-Span Structures

Long-span structures may require deviation from thenormal good practice of loose bolt assembly. Unless heldin shape by cables, struts, or backfill, longitudinal seamsshould be tightened when the plates are hung. Care mustbe taken to align plates to ensure properly fitted seamsprior to bolt tightening. This may require temporaryshoring. Follow the manufacturer’s instructions. The vari-ation before backfill shall not exceed 2% of the span orrise, whichever is greater, but shall not exceed 5 inches

except for horizontal ellipse shapes having a ratio of topto side radii of 3 or less where only the 2% restriction shallapply. The rise of arches with a ratio of top to side radii ofthree or more should not deviate from the specified di-mensions by more than 1% of the span.

Reinforcing ribs, when required to satisfy the structuraldesign, shall be attached to the structural plate corrugationcrown prior to backfilling using a bolt spacing of not morethan 12 inches. Legible identifying letters or numbersshall be placed on each rib to designate its proper positionin the finished structure.

Reinforcing ribs, when required only as a means of con-trolling structure shape during installation, shall be spacedand attached to the corrugated plates at the discretion of themanufacturer with the approval of the Engineer.

26.5 INSTALLATION

26.5.1 Placing Culverts—General

For trench conditions, the trench shall be excavated tothe width, depth, and grade shown on the plans and ap-proved by the Engineer.

Proper preparation of foundation, placement of foun-dation material where required, and placement of beddingmaterial shall precede the installation of all culvert pipe.This shall include necessary leveling of the native trenchbottom or the top of the foundation material as well asplacement and compaction of required bedding materialto a uniform grade so that the entire length of pipe will besupported on a uniform base. The backfill material shallbe placed and compacted around the pipe in a manner tomeet the requirements specified.

All pipes shall be protected by sufficient cover beforepermitting heavy construction equipment to pass overthem during construction.

Soil migration can weaken or destroy the support ca-pabilities of the soils around the pipe. Materials used forfoundation improvements, bedding and structure backfillmust have gradations compatible with adjacent soils toavoid migration. Where material gradations can not beproperly controlled, adjacent materials must be separatedwith a suitable geotextile.

26.5.2 Foundation

The foundation under the pipe and structure backfillshall be investigated for its ability to support the loads. Afoundation shall be provided such that the structure back-fill does not settle more than the pipe to avoid dragdownloads on the pipe.

The foundation must provide uniform support for thepipe invert. Boulders or rock under the pipe or soft spots



shall be excavated to a suitable depth and filled with back-fill material compacted sufficiently to provide uniformityas shown in Figure 26.5.2A.

Where the natural foundation is judged inadequate bythe Engineer to support the pipe or structure backfill, itshall be excavated to a suitable depth and replaced bybackfill material as shown in Figure 26.5.2B.

For shapes such as pipe arches, horizontal ellipses orunderpasses, where relatively large radius inverts adjoinsmall radius corners or sides, the foundation must supportthe radial pressures exerted by the smaller radius portionsof the pipe. These pressures, quantified in Division I, Sec-tion 12, “Soil-Corrugated Metal Structure Interaction Sys-tems,” may be two to five times the loading pressures ontop of the pipe, depending on the specific pipe shape. The

principal foundation support must be provided in the areasextending radially outward from the smaller radius areas.

The larger radius inverts exert proportionately lowerpressures. When corrective measures are necessary, provid-ing less support under the invert allows the pipe to maintainits shape as minor settlements occur. (See Figure 26.5.2C.)

Under high fills, where pipe settlements will not main-tain the necessary grade, pipe may be cambered to anamount sufficient to prevent excessive sag or back slope.The amount of camber must be determined by the Engi-neer based on considerations including the flow line gra-dient, fill height, the compressive characteristics of thefoundation materials and the depth to rock or other in-compressible materials. A camber detail is provided inFigure 26.5.2D.


FIGURE 26.5 Typical Cross-Section Showing Materials Around the Pipe


26.5.3 Bedding

The pipe bedding is a relatively thin layer of looselyplaced material to cushion the pipe invert and allow thecorrugation to rest or seat into it, thus supporting the cor-rugation. When, in the opinion of the Engineer, the naturalsoil does not provide a suitable bed, a bedding blanket

with a minimum thickness of twice the corrugation depthshall be provided.

Pipe arch, horizontal ellipse and underpass shapes withspans exceeding 12 feet should be placed on a shaped bed.The shaped area, centered beneath the pipe should have aminimum width of 1⁄ 2 the span for pipe arch and under-pass shapes and 1⁄ 3 the span for horizontal ellipse shapes.


FIGURE 26.5.2 A-D: Foundation Improvement Methods When Required


Preshaping may consist of a simple “V” graded into thesoil as shown in Figure 26.5.3.

26.5.4 Structural Backfill

26.5.4.1 General

Correct placement of materials of the proper qualityand moisture content is essential. Sufficient field testingmust be used to verify procedures, but is no substitute forinspection that ensures that the proper procedures are fol-lowed. This is of extreme importance because the struc-tural integrity of the corrugated metal structure is vitallyaffected by the quality of construction in the field.

Backfill material shall meet the requirements of Arti-cle 26.3.8 and shall be placed as shown in Figure 26.5.2Din layers not exceeding 8-inch loose lift thickness to aminimum 90% standard density per AASHTO T 99.Equipment used to compact backfill within 3 feet fromsides of pipe or from edge of footing for arches and boxculverts shall be approved by the Engineer prior to use.Except as provided below for long-span structures, theequipment used for compacting backfill beyond these lim-its may be the same as used for compacting embankment.

The backfill shall be placed and compacted with careunder the haunches of the pipe and shall be brought upevenly on both sides of the pipe by working backfill op-erations from side to side. The side to side backfill differ-ential shall not exceed 24 inches or 1⁄ 3 of the size of thestructure, whichever is less. Backfill shall continue to notless than 1 foot above the top for the full length of thepipe. Fill above this elevation may be material for em-bankment fill or other materials as specified to support thepavement. The width of trench shall be kept to the mini-mum width required for placing pipe, placing adequatebedding and sidefill, and safe working conditions. Pond-ing or jetting of backfill will not be permitted except uponwritten permission by the Engineer.

Where single or multiple structures are installed at askew to the embankment (i.e. cross the embankment atother than 90°), proper support for the pipe must be pro-vided. This may be done with a rigid, reinforced concretehead wall or by warping the embankment fill to provide thenecessary balanced side support. Figure 26.5.4 providesguidelines for warping the embankment.

26.5.4.2 Arches

Arches may require special shape control considera-tions during the placement and compaction of structurebackfill. Pin connections at the footing restrict uniformshape change. Arches may peak excessively and experi-ence curvature flattening in their upper quadrants. Usinglighter compaction equipment, more easily compactedstructure backfill, or top loading (placing a small load ofstructure backfill on the crown) will aid installation.

26.5.4.3 Long-Span Structures

Backfill requirements for long-span structural-platestructures are similar to those for smaller structures. Theirsize and flexibility require special control of backfill andcontinuous monitoring of structure shape. Prior to begin-ning construction, the manufacturer shall provide a pre-construction conference to advise the Contractor(s) andEngineer of the more critical functions to be performed.

Equipment and construction procedures used to back-fill long-span structural plate structures shall be such thatexcessive structure distortion will not occur. Structureshape shall be checked regularly during backfilling to ver-ify acceptability of the construction methods used. Mag-nitude of allowable shape changes will be specified by themanufacturer (fabricator of long-span structures). Themanufacturer shall provide a qualified shape control in-spector to aid the Engineer during the placement of allstructural backfill to the minimum cover level over thestructure (as required by the design to carry full highwayloads). The Inspector shall advise the Engineer on the ac-ceptability of all backfill material and construction meth-ods and the proper monitoring of the shape. Structurebackfill material shall be placed in horizontal uniform layers not exceeding an 8-inch loose lift thickness andshall be brought up uniformly on both sides of the struc-ture. Each layer shall be compacted to a density not lessthan 90% per AASHTO T 180. The structure backfillshall be constructed to the minimum lines and gradesshown on the plans, keeping it at or below the level ofadjacent soil or embankment. Permissible exceptions torequired structure backfill density are: the area under theinvert, the 12-inch to 18-inch width of soil immediatelyadjacent to the large radius side plates of high-profile


FIGURE 26.5.3 “V” Shaped Bed (Foundation)for Larger Pipe Arch, Horizontal Ellipse

and Underpass Structures


arches and inverted pear shapes, and the lower portion ofthe first horizontal lift of overfill carried ahead of andunder the small, tracked vehicle initially crossing thestructure.


Metal box culverts are not long-span structures in thatthey are relatively stiff, semi-rigid frames. They do not re-quire a preconstruction conference or shape control con-siderations beyond those of a standard metal culvert.

Structural backfill material shall be placed in uniformhorizontal layers not exceeding an 8-inch maximum looselift thickness and compacted to a density not less than90% per AASHTO T 180. The structural backfill shall beconstructed to the minimum lines and grades shown onthe plans, keeping it at or below the level of the adjacentsoil or embankment.

26.5.4.5 Bracing

When required, temporary bracing shall be installedand shall remain in place as long as necessary to protectworkmen and to maintain structure shape during erection.

For long-span structures which require temporarybracing or cabling to hold the structure in shape, the sup-ports shall not be removed until backfill is placed to an ad-equate elevation to provide the necessary support. In nocase shall internal braces be left in place when backfillingreaches the top quadrant of the pipe or the top radius arcportion of a long span.

26.5.5 Arch Substructures and Headwalls

Substructures and headwalls shall be designed in ac-cordance with the requirements of Division I.

The ends of the corrugated metal arch shall rest in akeyway formed into continuous concrete footings, or shallrest on a metal bearing surface, usually an angle or chan-nel shape, which is securely anchored to or embedded inthe concrete footing.

The metal bearing when specified may be a hot-rolledor cold-formed galvanized steel angle or channel, or anextruded aluminum angle or channel. These shapes shallbe not less than 3⁄ 16 inch in thickness and shall be se-curely anchored to the footing at a maximum spacing of24 inches. When the metal bearing member is not com-pletely embedded in a groove in the footing, one vertical


FIGURE 26.5.4 End Treatment of Skewed Flexible Culvert


leg shall be punched to allow the end of the corrugatedplates to be bolted to this leg of the bearing member.

Where an invert slab is provided which is not integralwith the arch footing, the invert slab shall be continuouslyreinforced.

26.5.6 Inspection Requirements for CMP

All pipe shall undergo inspection during and after in-stallation to ensure proper performance. Inspections at theappropriate times during installation will detect and allowearly correction of line and grade, jointing and shapechange problems. CMP installation can be properly mon-itored and evaluated by visual inspection. The timing andnumber of inspections required will vary with the signifi-cance of the installation.

Pipes shall be inspected by entering the pipe, or by in-spection from both the inlet and outlet (or other accesspoints) by visual means or through the use of videoequipment.

CMP shall be inspected after placement in the trench,and as required during backfilling to ensure that final in-stallation conditions allow the pipe to perform as de-signed. Construction inspection during early stages of theproject will allow the contractor to evaluate and, if nec-essary, modify construction and quality control practices.This is particularly important in deep installations.

The inspector will verify that bedding, backfill andcompaction requirements are followed during installa-tion. The pipe shall be checked for alignment, joint sep-aration, cracking at bolt holes, localized distortions,bulging, flattening, or racking. Minimum or near-minimum

cover installations should be inspected prior to and im-mediately after vehicular load is applied.

26.6 CONSTRUCTION PRECAUTIONS

These structures can carry legal highway loads oncethe backfill is placed and compacted to the minimumcover level over the pipe as defined by Division I, Section12, “Soil-Corrugated Metal Structure Interaction.” Forheavier construction loads, additional cover may be re-quired. Table 26.6 provides guidance for smaller struc-tures. Consult the Engineer or the manufacturer for guid-ance on structures or axle loads not listed.

The structure must be protected from hydraulic forcesduring construction, prior to the completion of permanenterosion control and end protection. Hydraulic forces maycause erosion, shape distortion, flotation or washout.

Backfill and other earth loads must be kept balanced.(See Article 26.5.4.)

26.7 MEASUREMENT

Corrugated metal and structural plate pipe, pipe arches,arches and box culverts shall be measured in lineal feet in-stalled in place, completed and accepted. The number oflineal feet shall be the average of the top and bottom cen-ter line lengths for pipe, the bottom center line length forpipe arches and box culverts, and the average of springingline lengths for arches.

26.8 PAYMENT

Separate pay items or provision for including excava-tion, backfill, and concrete for arches must be provided forin the contract.

The lengths as measured above will be paid for at thecontract prices per lineal foot bid for corrugated metal andstructural plate pipe, pipe-arch, arch or box culvert of thesizes specified. Such price and payment shall constitutefull compensation for furnishing, handling, erecting, andinstalling the pipe, pipe-arches, arches or box culverts,and for all materials, labor, equipment, tools and inciden-tals necessary to complete this item. Such price and pay-ment shall also include excavation, bedding material,backfill, concrete headwalls, endwalls and foundations forpipe, pipe-arches and box culverts. Separate payment willbe made for excavation, backfill, and concrete or masonryheadwalls and foundations for arches.


TABLE 26.6 Minimum Cover forConstruction Loads


Section 27CONCRETE CULVERTS

27.1 GENERAL

This work shall consist of fabricating, furnishing, andinstalling buried precast concrete culverts conforming tothese Specifications, the special provisions and the detailsshown on the plans. Precast reinforced concrete pipe shallbe circular, arch or elliptical, as specified. Precast rein-forced concrete box sections shall be of the dimensionsspecified or shown on the plans.


When complete details are not provided in the plans, orwhen required or permitted by provisions in the contract,the Contractor shall prepare and submit to the Engineerworking drawings of the structure or installation systemproposed for use. Fabrication or installation of the struc-ture shall not begin until the Engineer has approved thedrawings. The working drawings shall show complete de-tails and substantiating calculations of the structure, thematerials, equipment and installation methods the Con-tractor proposes to use.

Working drawings shall be submitted sufficiently inadvance of the start of the affected work to allow time forreview by the Engineer and correction of the submittal bythe Contractor without delaying the work. Approval bythe Engineer shall not relieve the Contractor of any re-sponsibility under the contract for the successful comple-tion of this work.

27.3 MATERIALS

27.3.1 Reinforced Concrete Culverts

The materials for reinforced concrete culverts shallmeet the requirements of the following specifications forthe classes and sizes specified above.

27.3.2 Joint Sealants

27.3.2.1 Cement Mortar

Mortar shall be composed of one part Portland cementand two parts sand by volume. Sand shall be well gradedand of such size that all will pass a No. 8 sieve. The ma-terials shall be mixed to a consistency suitable for the pur-pose intended and used within 30 minutes after the mix-ing water has been added. Admixtures, if any, shall beapproved by the Engineer prior to use.

27.3.2.2 Flexible Watertight Gaskets

Flexible watertight gasketed joints shall conform to therequirements of AASHTO M 198 and shall be flexible andcapable of withstanding expansion, contraction, and set-tlement of the pipeline.

All rubber gaskets shall be stored in as cool a place aspracticable, preferably at 70°F or less.

Rubber gaskets, of the type requiring lubrication, shallbe lubricated with the lubricant recommended and sup-plied by the manufacturer of the pipe.

669


27.3.2.3 Other Joint Sealant Materials

Other joint sealant materials shall be submitted for test-ing in advance of their use and shall not be used prior toreceiving approval by the Engineer.

27.3.3 Bedding, Haunch, Lower Side and Backfillor Overfill Material

27.3.3.1 Precast Reinforced Concrete Circular,Arch, and Elliptical Pipe

Bedding, haunch, lower side and overfill material shallconform to Figures 27.5A, 27.5B, 27.5C, and 27.5Dwhich define soil areas and critical dimensions, and Ta-bles 27.5A and 27.5B, which list generic soil types andminimum compaction requirements, and minimum bed-ding thicknesses for the four Standard Installation Types.The AASHTO Soil Classifications and the USCS SoilClassifications equivalent to the generic soil types in theStandard Installations are presented in Table 27.5C.

27.3.3.2 Precast Reinforced Concrete Box Sections

For precast reinforced concrete box sections, beddingand backfill material shall conform to Figure 27.5E withthe following exceptions. Bedding material may be sandor select sandy soil all of which passes a U.S. Standard 3⁄ 8-inch sieve and not more than 10% of which passes aU.S. Standard No. 200 sieve. Backfill may be select ma-terial and shall be free of organic material, stones largerthan 3 inches in the greatest dimension, frozen lumps, ormoisture in excess of that permitting the specified com-paction.

27.4 ASSEMBLY

27.4.1 General

Precast concrete units or elements shall be assembledin accordance with the manufacturer’s instructions. Allunits or elements shall be handled with reasonable careand shall not be rolled or dragged over gravel or rock.Care shall be taken to prevent the units from striking rockor other hard objects during placement.

Cracks in an installed precast concrete culvert that ex-ceed 0.01-inch width will be appraised by the Engineer con-sidering the structural integrity, environmental conditions,and the design service life of the culvert. Generally in non-corrosive environments, cracks 0.10 inch or less in width areconsidered acceptable; in corrosive environments, those

cracks 0.01 inch or less in width are considered acceptablewithout repair. Cracks determined to be detrimental shall besealed by a method approved by the Engineer.

27.4.2 Joints

Joints for reinforced concrete pipe and precast rein-forced concrete box sections shall comply with the detailsshown on the plans, the approved working drawings, andthe requirements of the special provisions. Each joint shallbe sealed to prevent infiltration of soil fines or water as re-quired by the contract documents. Joint sealant materialsshall comply with the provisions of Article 27.3.2.

The Contractor shall furnish to the Engineer a certifi-cate of compliance that the material being furnished con-forms to the joint property requirements. Field tests maybe required by the Engineer whenever there is a questionregarding compliance with contract requirements.

27.5 INSTALLATION

27.5.1 General

Trenches shall be excavated to the dimensions andgrade specified in the plans or ordered by the Engineer.The Contractor shall make such provisions as required toinsure adequate drainage of the trench to protect the bed-ding during construction operations. Proper preparation offoundation, placement of foundation material where re-quired, and placement of bedding material shall precedethe installation of the culvert. This shall include necessaryleveling of the native trench bottom or the top of founda-tion materials as well as placement and grading of re-quired bedding material to a uniform grade so that the en-tire length of pipe will be supported on a uniform slightlyyield bedding. The backfill material shall be placedaround the culvert in a manner to meet the requirementsspecified.

27.5.2 Bedding

27.5.2.1 General

If rock strata or boulders are encountered under theculvert within the limits of the required bedding, the rockor boulders shall be removed and replaced with beddingmaterial. Special care may be necessary with rock or otherunyielding foundations to cushion pipe from shock whenblasting can be anticipated in the area. Where, in the opin-ion of the Engineer, the natural foundation soil is such asto require stabilization, such material shall be replaced bya layer of bedding material. Where an unsuitable material




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.5B

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(peat, muck, etc.) is encountered at or below invert eleva-tion during excavation, the necessary subsurface explo-ration and analysis shall be made and corrective treatmentshall be as directed by the Engineer.

27.5.2.2 Precast Reinforced Concrete CircularArch and Elliptical Pipe

A bedding shall be provided for the type of installationspecified conforming to Figures 27.5A, 27.5B, 27.5C, and27.5D which define soil areas and critical dimensions, andTables 27.5A and 27.5B, which list generic soil types andminimum compaction requirements, and minimum bed-ding thicknesses for the four Standard Installation Types.


A bedding shall be provided for the type of installationspecified conforming to Figure 27.5E unless in the opin-ion of the Engineer, the natural soil provides a suitablebedding.

27.5.3 Placing Culvert Sections

Unless otherwise authorized by the Engineer, the lay-ing of culvert sections on the prepared foundation shall bestarted at the outlet and with the spigot or tongue endpointing downstream and shall proceed toward the inlet


FIGURE 27.5C Trench Beddings, Miscellaneous Shapes


end with the abutting sections properly matched, true tothe established lines and grades. Where pipe with bells isinstalled, bell holes shall be excavated in the bedding tosuch dimensions that the entire length of the barrel of thepipe will be supported by the bedding when properly in-stalled. Proper facilities shall be provided for hoisting andlowering the sections of culvert into the trench withoutdisturbing the prepared foundation and the sides of thetrench. The ends of the section shall be carefully cleanedbefore the section is jointed. The section shall be fitted andmatched so that when laid in the bed it shall form asmooth, uniform conduit. When elliptical pipe with circu-lar reinforcing or circular pipe with elliptical reinforcingis used, the pipe shall be laid in the trench in such positionthat the markings “Top” or “Bottom,” shall not be morethan 5° from the vertical plane through the longitudinalaxis of the pipe.

Multiple installations of reinforced concrete culvertsshall be laid with the center lines of individual barrels par-allel at the spacing shown on the plans. Pipe and boxsections used in parallel installations require positivelateral bearing between the sides of adjacent pipe or boxsections. Compacted earth fill, granular backfill, or grout-ing between the units are considered means of providingpositive bearing.

27.5.4 Haunch, Lower Side and Backfill or Overfill

27.5.4.1 Precast Reinforced Concrete CircularArch and Elliptical Pipe

27.5.4.1.1 Haunch Material

Haunch material shall be installed to the limits shownon Figure 27.5A, 27.5B, 27.5C, and 27.5D.


FIGURE 27.5D Embankment Beddings, Miscellaneous Shapes



TABLE 27.5A Standard Embankment Installation Soils and Minimum Compaction Requirements

Haunch and OuterInstallation Type Bedding Thickness Bedding Lower Side

Type 1 Bc/24�� minimum, 95% SW 90% SW, 95% MLnot less than or3��. If rock 100% CL

foundation, use Bc /12�� minimum, not less than 6��

Type 2 Bc/24�� minimum, 90% SW 85% SW, 90% MLnot less than or or

(See Note 3.) 3��. If rock 95% ML 95% CLfoundation, use

Bc /12�� minimum, not less than 6��

Type 3 Bc/24�� minimum, 85% SW, 90% ML, or 85% SW, 90% MLnot less than 95% CL or

(See Note 3.) 3��. If rock 95% CLfoundation, use

Bc /12�� minimum, not less than 6��

Type 4 No bedding required, No compaction No compactionexcept if rock foundation, required, except if CL, required, except if

use Bc /12�� minimum, use 85% CL CL, use 85% CLnot less than 6��

NOTES:

.11. Compaction and soil symbols—i.e. “95% SW” refers to SW soil material with a minimum standard proc-tor compaction of 95%. See Table 27.5C for equivalent modified proctor values.

.12. Soil in the outer bedding, haunch, and lower side zones, except within Bc /3 from the pipe springline, shallbe compacted to at least the same compaction as the majority of soil in the overfill zone.

.13. Only Type 2 and 3 installations are available for horizontal elliptical, vertical elliptical and arch pipe.

.14. SUBTRENCHES

4.1 A subtrench is defined as a trench with its top below finished grade by more than 0.1H or, for roadways, itstop is at an elevation lower than 1� below the bottom of the pavement base material.

4.2 The minimum width of a subtrench shall be 1.33 Bc, or wider if required for adequate space to attain thespecified compaction in the haunch and bedding zones.

4.3 For subtrenches with walls of natural soil, any portion of the lower side zone in the subtrench wall shouldbe at least as firm as an equivalent soil placed to the compaction requirements specified for the lower sidezone and as firm as the majority of soil in the overfill zone, or shall be removed and replaced with soil com-pacted to the specified level.



TABLE 27.5B Standard Trench Installation Soils and Minimum Compaction Requirements

Haunch and OuterInstallation Type Bedding Thickness Bedding Lower Side

Type 1 Bc/24�� minimum, 95% SW 90% SW, 95% MLnot less than 100% CL, or3��. If rock natural soils of

foundation, use equal firmnessBc/12�� minimum, not less than 6��

Type 2 Bc/24�� minimum, 90% SW 85% SW, 90% MLnot less than or 95% CL, or

(see Note 3) 3��. If rock 95% ML natural soils offoundation, use equal firmness

Bc/12�� minimum, not less than 6��

Type 3 Bc/24�� minimum, 85% SW, 90% ML, or 85% SW, 90% MLnot less than 95% CL 95% CL, or

(see Note 3) 3��. If rock natural soils offoundation, use equal firmness

Bc/12�� minimum, not less than 6��

Type 4 No bedding required, No compaction 85% SW, 90% MLexcept if rock foundation, required, except if CL, 95% CL, or

use Bc /12�� minimum, use 85% CL natural soils ofnot less than 6�� equal firmness

NOTES:

1. Compaction and soil symbols—i.e. “95% SW” refers to SW soil material with a minimum standard proctorcompaction of 95%. See Table 27.5C for equivalent modified proctor values.

2. The trench top elevation shall be no lower than .0.1H below finished grade or, for roadways, its top shall beno lower than an elevation of 1� below the bottom of the pavement base material.

3. Only Type 2 and 3 installations are available for horizontal elliptical, vertical elliptical and arch pipe.

4. Soil in bedding and haunch zones shall be compacted to at least the same compaction as specified for the ma-jority of soil in the backfill zone.

5. The trench width shall be wider than shown if required for adequate space to attain the specified compactionin the haunch and bedding zones.

6. For trench walls that are within 10 degrees of vertical, the compaction or firmness of the soil in the trenchwalls and lower side zone need not be considered.

7. For trench walls with greater than 10-degree slopes that consist of embankment, the lower side shall be com-pacted to at least the same compaction as specified for the soil in the backfill zone.


27.5.4.1.2 Lower Side Material

Lower side material shall be installed to the limitsshown on Figures 27.5A, 27.5B, 27.5C, and 27.5D.

27.5.4.1.3 Overfill

Overfill material shall be installed to the limits shownon Figures 27.5A, 27.5B, 27.5C, and 27.5D.


27.5.4.2.1 Backfill

Backfill material shall be installed to the limits shownon Figure 27.5E for the embankment or trench condition.Trenches shall have vertical walls and no over-excavatingor sloping sidewalls shall be permitted.

27.5.4.3 Placing of Haunch, Lower Side andBackfill or Overfill

Generally, compaction of fill material to the requireddensity is dependent on the thickness of the layer of fillbeing compacted, soil type, soil moisture content, type ofcompaction equipment, and amount of compactive forceand the length of time the force is applied. Fill materialshall be placed in layers with a maximum thickness of 8 inches and compacted to obtain the required density. Thefill material shall be placed and compacted with care underthe haunches of the culvert and shall be brought up evenlyand simultaneously on both sides of the culvert. For thelower haunch areas of Type 1, 2, and 3 Standard Installa-tions, soils requiring 90% or greater Standard Proctor den-sities shall be placed in layers with a maximum thicknessof 4 inches and compacted to obtain the required density.The width of trench shall be kept to the minimum requiredfor installation of the culvert. Ponding or jetting will beonly by the permission of the Engineer.


TABLE 27.5C Equivalent USCS and AASHTO Soil Classifications for SIDD Soil Designations

Representative Soil Types Percent Compaction

Standard ModifiedSIDD Soil USCS AASHTO Proctor Proctor

Gravelly SW, SP A1, A3 100 95Sand GW, GP 95 90(SW) 90 85

85 8080 7561 59

Sandy GM, SM, ML A2, A4 100 95Silt Also GC, SC 95 90

(ML) with less than 20% 90 85passing No. 200 sieve 85 80

80 7549 46

Silty GL, MH A5, A6 100 90Clay GC, SC 95 85(CL) 90 80

85 7580 7045 40

CH A7 100 9095 8590 8045 40


27.5.4.4 Cover Over Culvert During Construction

Culverts shall be protected by a minimum of 3 feet ofcover to prevent damage before permitting heavy con-struction equipment to pass over them during construction.

27.6 MEASUREMENT

Culverts shall be measured in linear feet installed inplace, completed, and accepted. The number of feet shallbe the average of the top and bottom center line lengthsfor pipe and box sections.

27.7 PAYMENT

The length determined as herein given shall be paid forat the contract unit prices per linear foot bid for culvertsof the several sizes and shapes, as the case may be, whichprices and payments shall constitute full compensation forfurnishing, handling, and installing the culvert and for allmaterials, labor, equipment, tools, and incidentals neces-sary to complete this item. Such price and payment shallalso include excavation, bedding material, backfill, rein-forced concrete headwalls and endwalls, and any requiredfoundations.


FIGURE 27.5E


Section 28WEARING SURFACES

28.1 DESCRIPTION

This work shall consist of placing a wearing surface ofdurable and impervious material on the roadway surfaceof bridge decks. It also includes the preparation of the sur-faces of either existing or new decks to receive such anoverlay of surfacing material.

The type and thickness of the wearing surface shall beas designated on the plans. The materials and installationrequirements for wearing surfaces of types other thanlatex modified concrete shall be as specified in the specialprovisions. Latex modified concrete wearing surfacesshall be furnished and installed in accordance with theseSpecifications.

28.2 LATEX MODIFIED CONCRETE TYPEWEARING SURFACE

28.2.1 General

All equipment used to prepare the surface and to pro-portion, mix, place and finish the latex concrete shall besubject to approval by the Engineer prior to use. This ap-proval will be contingent on satisfactory performance andwill be rescinded in the event such performance is notbeing achieved. Equipment shall be on hand sufficientlyahead of the start of construction operations to be exam-ined and approved. Any equipment leaking oil or anyother containment onto the deck shall be immediatelyremoved from the job site until repaired.

A technician who is well experienced in the propor-tioning, mixing, placing and finishing of latex modifiedconcrete shall be employed by the Contractor and shall bepresent and in technical control of the work wheneverthese operations are underway. The qualifications of thistechnician which includes a list of projects on which thetechnician was employed and the technician’s level of re-sponsibility on each shall be submitted to and approvedby the Engineer prior to the start of these operations.

Approval by the Engineer of equipment or techniciansshall not relieve the Contractor of any responsibility underthe contract for the successful completion of the work.

If not otherwise shown on the plans, the minimumthickness of latex modified concrete wearing surfacesshall be 11 ⁄4 inches.

28.2.2 Materials

28.2.2.1 Portland Cement

Portland cement shall conform to the requirement ofArticle 8.3.1 of Section 8, “Concrete Structures,” exceptthat only Types I or II shall be used.

28.2.2.2 Aggregate

Aggregate shall conform to the requirements ofAASHTO M 6 for fine aggregate and to AASHTO M 80for coarse aggregate. Coarse aggregate shall be graded 1 ⁄2 inch to No. 4 per AASHTO M 43.

28.2.2.3 Water

Water for mixing concrete shall conform to therequirements of Article 8.3.2.

28.2.2.4 Latex Emulsion

Formulated latex emulsion admixture shall be a non-hazardous, film forming, polymeric emulsion in water towhich all stabilizers have been added at the point ofmanufacture and shall be homogeneous and uniform incomposition.

Physical Properties—The latex modifier shall conformto the following requirements:

Polymer Type Stabilizers Styrene Butadiene(a) Latex .............................. Nonionic Surfactants(b) Portland Cement

Composition ............... Polydimethyl SiloxanePercent Solids ................................................. 46.0–49.0Weight per Gallon (lbs at 25°C) ..................................8.4Color .......................................................................White

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A Certificate of Compliance signed by the manufac-turer of the latex emulsion certifying that the material con-forms to the above specifications shall be furnished foreach shipment used in the work.

Latex admixture to be stored shall be kept in suitableenclosures which will protect it from freezing and fromprolonged exposure to temperatures in excess of 85°F.Containers of latex admixture may be stored at the bridgesite for a period not to exceed 10 days. Such stored con-tainers shall be covered completely with suitable insulat-ing blanket material to avoid excessive temperatures.

28.2.2.5 Latex Modified Concrete

The latex modified concrete for use on this projectshall be a workable mixture and meet the followingrequirements.

NOTES:

1. Following sampling of the discharged, normallymixed material, the commencement of the slumptest shall be delayed from 4 to 5 minutes.

2. Water may be added to obtain slump within the pre-scribed limits.

3. The dry weight ratios are approximate and shouldproduce good workability, but due to gradationchanges may be adjusted within limits by the Engi-neer. The parts by weight of sand may be increasedby as much as 0.2 if the coarse aggregate is reducedby an equivalent volume.


28.2.3.1 New Decks

The surfaces of new decks upon which a wearing sur-face overlay is to be placed shall be finished to a roughtexture by coarse brooming or other approved methods.

After curing of the deck concrete is complete and be-fore placing the overlay, the entire area of the deck surfaceand the vertical faces of curbs, concrete parapets, barrier

walls, etc., up to a height of 1 inch above the top elevationof the overlay shall be blast cleaned to a bright, clean ap-pearance which is free from laitance, curing compound,dust, dirt, oil, grease, bituminous material, paint, and allforeign matter. The blast cleaning of an area of the deckshall normally be performed within the 24-hour periodpreceding placement of the overlay on the area. The blastcleaning may be performed by either wet sandblasting,high pressure water blasting, blasting grits, shrouded drysandblasting with dust collectors, or other method ap-proved by the Engineer. Water blasting equipment shalloperate with a minimum pressure of 3,500 psi. Themethod used shall be performed so as to conform to ap-plicable air and water pollution regulations and to applic-able safety and health regulations. All debris, includingdirty water, resulting from the blast cleaning operationsshall be immediately and thoroughly cleaned from theblast-cleaned surfaces and from other areas where debrismay have accumulated. The blast cleaned areas shall beprotected, as necessary, against contamination prior toplacement of the overlay. Contaminated areas and areasexposed more than 36 hours after cleaning shall be blastcleaned again as directed by the Engineer at the Contrac-tor’s expense.

Just prior to placement of the overlay, all dust and otherdebris shall be removed by flushing with water or blow-ing with compressed air. The prepared surface shall thenbe soaked with clean water for not less than 1 hour priorto the placement of the latex overlay. Before the overlayis applied, all free water shall be blown out and off, andthis procedure shall continue until the surface appears dryor barely damp.

The air supply system for blast cleaning and blowingshall be equipped with an oil trap in the air line, and pro-visions shall be made to prevent oil or grease contamina-tion of the surface by any equipment prior to placement ofthe overlay.

28.2.3.2 Existing Decks

The surface of existing decks that have become conta-minated by traffic usage or by deicing salts shall be scar-ified to the depth shown on the plans or specified. If nodepth is shown or specified, a minimum of 1⁄ 4 inch of ma-terial shall be removed by scarification.

Prior to beginning scarification and until operations arecompleted, all deck drains, expansion joints and otheropenings where damage could result, as determined by theEngineer, shall be temporarily covered or plugged to pre-vent entry of debris.

Scarifying shall be done with power-operated mechan-ical scarifiers, or other approved devices, capable of uni-formly removing the existing surface to the depths re-



quired without damaging the underlying concrete. Ma-chine scarifiers shall not be operated so as to damage hard-ware such as drain grates and expansion joint armor. Inareas where machine scarifying cannot reach and in areasof spalling and where steel reinforcement is exposed,scarifying and the removal of deteriorated or unsoundconcrete shall be accomplished with hand tools. Pneu-matic hammers heavier than nominal 45 pounds shall notbe used.

No scarifying or chipping will be allowed within 6 feetof a new overlay until 48 hours after its placement.

In areas where deteriorated or unsound concrete is en-countered, as determined by the Engineer, the concreteshall be removed to a depth of 3 ⁄4-inch below the top matof reinforcing steel. A minimum of 3 ⁄4-inch clearance shallbe required around the reinforcing steel except wherelower bar mats make this impractical. Care shall be exer-cised to prevent damaging the exposed reinforcing steel.All reinforcing steel shall be blast-cleaned. The repairareas are to be filled during the overlay operation.

After scarification and removal of unsound concretehas been completed, the deck surface shall be blastcleaned and prepared as specified for new decks.

28.2.4 Proportioning and Mixing

The Contractor shall submit to the Engineer for ap-proval, 14 calendar days prior to date of placement, theproposed mix design in writing and samples of all mixmaterials in sufficient quantity to produce a minimum of3 cubic feet of concrete for laboratory mix design testing.

Proportioning and mixing equipment shall be of a self-contained, mobile, continuous-mixing, volumetric pro-portioning type mixer.

Continuous-type mixers shall be equipped so that theproportions of the cement, natural sand, and coarse ag-gregate can be fixed by calibration of the mixer and can-not be changed without destroying a seal or other indicat-ing device affixed to the mixer. In addition to beingequipped with a flow meter for calibrating the water sup-ply portion of the mixer, the mixer shall also be equippedwith a cumulative-type water meter which can be read tothe nearest 0.1 gallon. The water meters shall be readilyaccessible, accurate to within 1%, and easy to read. Bothwater meters shall be subject to checking by the Engineereach time the mixer is calibrated. Approved methods foradding the admixture shall be provided. The admixturesshall be added so as to be kept separated as far as is prac-ticable. The continuous type mixer shall be calibrated tothe satisfaction of the Engineer prior to starting the work.Yield checks normally will be made for each 50 cubic yards of mix. Recalibration will be necessarywhen indicated by the yield checks, and at any other times

the Engineer deems necessary to ensure proper propor-tioning of the ingredients. Continuous type mixers whichentrap unacceptable volumes of air in the mixture shallnot be used.

The mixer shall be kept clean and free of partially driedor hardened materials at all times. It shall consistently pro-duce a uniform, thoroughly blended mixture within thespecified air content and slump limits. Malfunctioningmixers shall be immediately repaired or replaced with ac-ceptable units.

Aggregate stockpiles being used should be of uniformmoisture content.

Mixing capability shall be such that finishing opera-tions can proceed at a steady pace with final finishingcompleted before the formation of the plastic surface film.

28.2.5 Installation

28.2.5.1 Weather Restrictions

The placement of latex modified concrete shall not bestarted when the temperature is, or is expected to fallbelow 45°F or rise above 80°F, or when high winds, rainor low humidity conditions are expected prior to final setof the concrete. If any of these conditions occur duringplacement, the placement shall be terminated and astraight construction joint formed. Placement at night maybe necessary when daytime conditions are not favorable.If placement is performed at night, adequate lighting shallbe provided by the Contractor.

28.2.5.2 Equipment

Placing and finishing equipment shall include handtools for placement and brushing-in freshly mixed latexmodified concrete and for distributing it to approximatelythe correct level for striking-off with the screed. Hand-op-erated vibrators, screeds and floats shall be used for con-solidating and finishing small areas.

An approved finishing machine complying with thefollowing requirements shall be used for finishing all largeareas of work:

The finishing machine shall be self-propelled and ca-pable of forward and reverse movement underpositive control. The length of the screed shall besufficient to extend at least 6 inches beyond theedge of both ends of the section being placed. Thefinishing machine shall also be capable of consoli-dating the concrete by vibration and of raising allscreeds to clear the concrete for traveling in reverse.The machine shall be either a rotating roller type oran oscillating screed type.



Rotating roller-type machines shall have one or morerollers, augers, and 1,500 to 2,500 vpm vibratorypans.

Oscillating screed-type machines shall have vibra-tors on the screeds whose frequency of vibrationcan be varied between 3,000 and 15,000 vpm. Thebottom face of the screeds shall be not less than 4inches wide and shall be metal.

Rails will be required for the finishing machine to travelon. Rails shall be sufficiently rigid to support the weight ofthe machine without appreciable deflection and shall beplaced outside of the overlay area. Rail anchorages shallprovide horizontal and vertical stability and shall not beballistically shot into concrete that will not be overlaid.

A suitable portable lightweight or wheeled work bridgeshall be furnished for use behind the finishing operation.

28.2.5.3 Placing and Finishing

28.2.5.3.1 Construction Joints

Planned construction joints shall be formed by bulk-heads set to grade. Before placing concrete against previ-ously placed overlay material, the construction joint shallbe sawed to a straight vertical edge. Sawing of joints maybe omitted if the bulkhead produces a straight, smooth,vertical surface. The face of the joint shall be sand orwater blasted to remove loose material.

Longitudinal construction joints will be permitted onlyat the center line of roadway or at lane lines unless other-wise shown on the plans or permitted by the Engineer.

In case of delay in the placement operation exceeding 1hour in duration, an approved construction joint shall beformed by removing all material not up to finish grade andsawing the edge in a straight line. During minor delays of1 hour or less, the end of the placement may be protectedfrom drying with several layers of clean, wet burlap.

28.2.5.3.2 Placing

The finishing machine shall be test run over the entirearea to be overlayed each day before placement is startedto ensure that the required overlay thickness will beachieved.

Immediately ahead of placing the overlay mixture, athin coating of the polymer modified concrete mixture tobe used for the overlay shall be thoroughly brushed andscrubbed onto the surface as a grout-bond coat for theoverlay. Coarser particles of the mixture which cannot bescrubbed into contact with the surface shall be removedand disposed of in a manner approved by the Engineer.Care shall be taken to insure that all vertical as well as hor-izontal surfaces receive a thorough, even coating and that

the rate of progress is limited so that the material brushedon does not become dry before it is covered with the fulldepth of latex modified concrete.

The latex modified concrete shall be placed on the pre-pared and grout-coated surface immediately after beingmixed. The mixture shall be placed and struck off ap-proximately 1 ⁄4 inch above final grade then consolidatedby vibration and finished to final grade with the approvedfinishing machine. Spud vibrators will be required in deeppockets, along edges, and adjacent to joint bulkheads.Supplemental vibration shall be provided along the meetlines where adjacent pours come together and along curblines. Hand finishing with a float may be required alongthe edge of the pour or on small areas of repair.

Screed rails and construction bulkheads shall be sepa-rated from the newly placed material by passing a pointingtrowel along their inside face. Expansion dams shall not beseparated from the overlay. Care shall be exercised to en-sure that this trowel cut is made for the entire depth andlength of rails after the mixture has stiffened sufficiently.

28.2.5.3.3 Finishing

The finishing equipment shall be operated so as to pro-duce a uniform, smooth, and even-textured surface. Thefinal surface shall not vary more than 1 ⁄8 inch from a 10-foot straightedge placed longitudinally thereon. Beforethe plastic film forms, the surface shall be textured by tin-ing in accordance with the requirements of Article 8.10.2.3.

28.2.6 Curing

The surface shall be promptly covered with a singlelayer of clean, wet burlap as soon as the surface will sup-port it without deformation.

Within 1 hour of covering with wet burlap, the burlapshall be rewet if necessary and a layer of 4-mil polyethyl-ene film, or wet burlap-polyethylene sheets, shall beplaced on the wet burlap, and the surface cured for 24hours. The curing material shall then be removed for anadditional 72 hours of air cure. If the temperature fallsbelow 45° during curing, the duration of the wet cure shallbe extended as directed by the Engineer.

The overlay shall be protected from freezing during thecure period.

Traffic will not be permitted on the overlay while it iscuring.

28.2.7 Acceptance Testing

After curing is completed, the overlay will be visuallyinspected for cracking or other damage, and inspected fordelaminations and bond failures by the use of a chain dragor other suitable device.



Surface cracks not exceeding 3 ⁄8 inch in depth shall besealed with an epoxy penetrating sealer followed by anapplication of approved sand.

Any cracks exceeding 3 ⁄8 inch in depth shall berepaired by methods approved by the Engineer, or theaffected portions of the wearing surface shall be removedand replaced. Any delaminated or unbonded portions ofthe wearing surface or portions damaged by rain or freez-ing shall be removed and replaced.

After completion of the wet cure, the surface shall betested for flatness and corrected, if necessary, as providedin Article 8.10.2.4.

All corrective work will be at the Contractor’s ex-pense.


Wearing surfaces and areas requiring scarification willbe measured by the square foot based on dimensions ofthe completed work.

Wearing surfaces will be paid for at the contract priceper square foot. Except as otherwise provided, thepayment per square foot for wearing surfaces shall beconsidered to be full compensation for the cost offurnishing all labor, materials, equipment, incidentals,and for doing all work involved in preparing the surfaceand constructing the wearing surface as shown on theplans and specified.

When a separate item is included in the bid schedulefor scarifying bridge decks, scarifying will be paid for bythe contract price per square foot. Such payment shall beconsidered to be full compensation for all costs involvedwith the scarifying work including removal and disposalof debris.

The removal of unsound concrete which is encoun-tered below the depth specified for scarifying will be paidfor as extra work.



Section 29EMBEDMENT ANCHORS

29.1 DESCRIPTION

This specification covers installation and field testingof cast-in-place, grouted, adhesive-bonded, expansionand undercut steel anchors.

29.2 PREQUALIFICATION

Prequalify all concrete anchors, including cast-in-place, all bonded anchor systems (including grout, chem-ical compounds, and adhesives), and undercut by univer-sal test standards designed to allow approved anchorsystems to be employed for any construction attachmentuse.

Conduct test for adhesive-bonded and other bondingcompounds in accordance with ASTM E 1512 (StandardTest Methods for Testing Bond Performance of Adhesive-Bonded Anchors).

Test expansion types to ASTM E 488 (Standard TestMethods for Strength of Anchors in Concrete and Ma-sonry Elements).

Comply with ACI 349-85 (Code Requirements forNuclear Safety Related Concrete Structures—AppendixB, Steel Embedments).

Provide certified test reports prepared by an indepen-dent laboratory documenting that the system (except me-chanical expansion anchors) is capable of achieving theminimum tensile strength of the embedment steel.

29.3 MATERIALS

Provide mill test reports certifying physical properties,chemistry, and strengths.

The chemical compounds acceptable for adhesive an-chors may include epoxies, polyesters, or vinylesters. Ad-hesive compounds which are moisture-insensitive, high-modulus, high-strength, and low-shrinkage should beused.

The use of additives to grout, and bonding materialswhich will be corrosive to steel or zinc/cadmium coatingsis prohibited.

29.4 CONSTRUCTION METHODS

Provide adequate edge distance, embedment depth andspacing to develop the required strength of the embed-ment anchors. Use the correct drill hole diameter as permanufacturer’s instructions. Use rotary impact drillingequipment unless diamond core drilling has been speci-fied and tested. If reinforcing bar is encountered duringthe drilling operation, move to a different location, or drillthrough the reinforcing steel using a diamond core bit asdirected by the Engineer. Patch abandoned holes with anapproved bonding material. Clean holes thoroughly asrecommended by the manufacturer. Remove all loose dustand concrete particles from hole. Prepare bonding mater-ial and install anchors according to instructions providedby the manufacturer or approved by the Engineer.Embedded anchors which are improperly installed orwhich do not have the required strength shall be removedand replaced to the satisfaction of the Engineer at theContractor’s expense.

29.5 INSPECTION AND TESTING

Where specified, conduct sacrificial tests of the anchorsystem on the job site to ultimate loads to document thecapability of the system to achieve pullout loads equalingthe full minimum tensile value of the anchor employed.Test the anchor on fully cured concrete samples. Unlessspecified otherwise, test no fewer than three (3) anchors byASTM E 488 methods. The Contractor may use any pre-qualified anchor systems meeting the above requirements.

Provide, without delay in progress, for an alternate sys-tem that will reach the designated pull-out requirement ifthe job site proofloading proves incapable of achievingminimum tensile values (or the designer’s required load iftoo little concrete exists in which to develop full ductileloads).

After installing the curing of bonding material, torqueeach anchor system to values specified. If torque valuesare not specified, use values recommended by the manu-facturer or provided by the Engineer.

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29.6 MEASUREMENT

Count and summarize each embedment anchor typesatisfactorily installed for the Contract, according to an-chor system, orientation (vertical, diagonal, and horizon-tal), and size (diameter).

29.7 PAYMENT

Payment for the quantity of embedment anchors deter-mined under measurement for each embedment anchortype, shall include full compensation for furnishing alllabor, materials, tools, equipment, testing, and incidentalsnecessary to place each anchor type.



Section 30THERMOPLASTIC PIPE

30.1 GENERAL

30.1.1 Description

This work shall consist of furnishing and installingthermoplastic pipe in conformance with these Specifica-tions, any special provisions, and the details shown on theplans. As used in this specification, thermoplastic pipe isdefined in Division I, Section 17, “Soil-ThermoplasticPipe Interaction Systems.”

30.1.2 Workmanship and Inspection

All thermoplastic pipe materials shall conform to theworkmanship and inspection requirements of AASHTOM 278, M 294, or M 304; or ASTM F 679, F 714, F 794,or F 894 as applicable.


Whenever specified or requested by the Engineer, theContractor shall provide manufacturer’s installation in-structions or working drawings with supporting data insufficient detail to permit a structural review. Sufficientcopies shall be furnished to meet the needs of the Engi-neer and other entities with review authority. The work-ing drawings shall be submitted sufficiently in advanceof proposed installation and use to allow for their review,revision, if needed, and approval without delay of thework. The Contractor shall not start construction of anythermoplastic pipe installations for which working draw-ings are required until the drawings have been approvedby the Engineer. Such approval will not relieve the Con-tractor of responsibility for results obtained by use ofthese drawings or any of the other responsibilities underthe contract.

30.3 MATERIALS

30.3.1 Thermoplastic Pipe

Polyethylene pipe shall conform to the requirements ofAASHTO M 294, or ASTM F 714, or ASTM F 894.

Poly(Vinyl Chloride) (PVC) pipe shall conform to therequirements of AASHTO M 278 or M 304; or ASTM F679 or F 794.

30.3.2 Bedding Material and Structural Backfill

Bedding and structural backfill shall meet the re-quirements of AASHTO M 145, A-1, A-2-4, A-2-5, or A-3. Bedding material shall have a maximum particle sizeof 1.25 inch. Backfill for thermoplastic pipe shall be freeof organic material, stones larger than 11⁄2 inch in great-est dimension, or frozen lumps. Moisture content shallbe in the range of optimum (typically �3% to �2%) per-mitting thorough compaction. Consideration should begiven to the potential for migration of fines from adja-cent materials into open-graded backfill and beddingmaterials.

For pipe types that are not smooth on the outside (cor-rugated or profile walls), backfill gradations should be se-lected that will permit the filling of the corrugation or pro-file valleys.

Flowable fills, such as controlled low strength mortar(CLSM) or controlled density fill (CDF), may be usedfor backfill and bedding provided adequate flotation re-sistance can be achieved by restraints, weighting, orplacement technique. With CLSM backfill, trench widthcan be reduced to a minimum of the outside diameterplus 12 inches. When CLSM is used all joints shall havegaskets.

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30.4 ASSEMBLY

30.4.1 General

Thermoplastic pipe shall be assembled in accordancewith the manufacturer’s instructions. All pipe shall be un-loaded and handled with reasonable care. Pipe shall not berolled or dragged over gravel or rock and shall be pre-vented from striking rock or other hard objects duringplacement in trench or on bedding.

Thermoplastic pipe shall be placed in the bed startingat the downstream end.

30.4.2 Joints

Joints for thermoplastic pipe shall meet the perfor-mance requirements for soiltightness unless watertight-ness is specified.

30.4.2.1 Field Joints

Joints shall be so installed that the connection of pipesections will form a continuous line free from irregulari-ties in the flow line. Suitable field joints can be obtainedwith the following types of connections:

(a) Corrugated bands (with or without gaskets)(b) Bell and spigot pipe ends (with or without gaskets)(c) Double bell couplings (with or without gaskets)

30.5 INSTALLATION

30.5.1 General Installation Requirements

Trenches must be excavated in such a manner as to in-sure that the sides will be stable under all working condi-tions. Trench walls shall be sloped or supported in con-formance with all standards of safety. Only as muchtrench as can be safely maintained shall be opened. Alltrenches shall be backfilled as soon as practicable, but notlater than the end of each working day.

Trench details, including foundation, bedding, haunch-ing, initial backfill, final backfill, pipe zone, and trenchwidth are shown in Figure 30.5.1.

30.5.2 Trench Widths

Trench width shall be sufficient to ensure workingroom to properly and safely place and compact haunchingand other backfill materials. The space between the pipe


FIGURE 30.5.1


and trench wall must be wider than the compaction equip-ment used in the pipe zone. Minimum trench width shallnot be less than 1.5 times the pipe outside diameter plus12 inches. Trench width in unsupported, unstable soilswill depend on the size of the pipe, the stiffness of thebackfill and in situ soil, and the depth of cover. The trenchshall be excavated to the width, depth, and grade as indi-cated on the plans and/or given by the Engineer.

30.5.3 Foundation and Bedding

Foundation and bedding shall meet the requirements ofArticle 30.3.2 and shall be installed as required by the En-gineer according to conditions in the trench bottom. A sta-ble and uniform bedding shall be provided for the pipeand any protruding features of its joint and/or fittings. Themiddle of the bedding equal to one-third the pipe O.D.should be loosely placed, while the remainder shall becompacted to a minimum 90% of maximum density perAASHTO T 99. A minimum of 4 inches of bedding shallbe provided prior to placement of the pipe unless other-wise specified.

When rock or unyielding material is present in thetrench bottom, a cushion of bedding of 6 inches minimumthickness shall be provided below the bottom of the pipe.

When the trench bottom is unstable, material shall beexcavated to a depth as required by the Engineer and re-placed with a suitable foundation. A suitably graded ma-terial shall be used where conditions may cause migrationof fines and loss of pipe support.

30.5.4 Structural Backfill

Structural backfill shall meet the requirements of Arti-cle 30.3.2. Structural backfill shall be placed and com-pacted in layers not exceeding an 8 inch loose lift thick-ness and brought up evenly and simultaneously on bothsides of the pipe to an elevation not less than one footabove the top of the pipe. Structural backfill must beworked into the haunch area and compacted by hand.

A minimum compaction level of 90% standard densityper AASHTO T 99 shall be achieved. Special compactionmeans may be necessary in the haunch area (See Figure30.5.1). All compaction equipment used within 3 feet ofthe pipe shall be approved by the Engineer. Ponding or

jetting the structural backfill to achieve compaction shallnot be permitted without written permission from the Engineer.

Backfill materials more than one foot above the pipe tofinal grade shall be selected, placed, and compacted to sat-isfy the loading, pavement, and other requirements abovethe pipe.

30.5.5 Minimum Cover

A minimum depth of cover above the pipe should bemaintained before allowing vehicles or heavy construc-tion equipment to traverse the pipe trench. The minimumdepth of cover should be established by the Engineerbased on an evaluation of specific project conditions. Forembedment materials installed to the minimum densitygiven in Article 30.5.4, cover of at least 24 inches shall beprovided before allowing vehicles or construction equip-ment to cross the trench surface. Hydrohammer type com-pactors shall not be used over the pipe.

30.5.6 Installation Deflection

The internal diameter of the barrel shall not be reducedby more than 5% of its base inside diameter when measurednot less than 30 days following completion of installation.

30.6 MEASUREMENT

Pipe installations shall be measured in linear feet in-stalled in place, completed, and accepted. The number offeet shall be the centerline lengths of the pipe.

30.7 PAYMENT

The length as measured above will be paid for at thecontract prices per lineal foot bid for thermoplastic pipeof the sizes specified. Such price and payment shall con-stitute full compensation for furnishing, handling, and in-stalling the pipe and for all materials, labor, equipment,tools, and incidentals necessary to complete this item.Such price and payment shall also include excavation,bedding material, backfill, headwalls, endwalls, and foun-dations for pipe.



HB-17_3

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Transcript of HB-17_3