Compare 2005 ASD to 1989 ASD

32
COMPARISON OF ANSI/AISC 360-05 TO 1989 ASD SPECIFICATION (prepared by James Falls and Jie Zuo) This document summarizes the revisions made to the ASD provisions contained in the 2005 AISC Specification for Structural Steel Buildings (ANSI/AISC 360-05) compared to the 1989 Specification for Structural Steel Buildings, Allowable Stress Design and Plastic Design. CHAPTER A GENERAL PROVISIONS A1. SCOPE The scope was expanded to include “other structures” in addition to structural steel buildings. Alternate methods of design based on tests and analysis are permitted subject to the approval of the authority having jurisdiction. Paragraphs pertaining to design of single angle members and structural joints were removed. Recommendations for design of cold-formed steel structural members were removed and replaced with a User Note. A1.1. Low-Seismic Applications (new) When the seismic response modification coefficient, R, is equal to or less than 3, the design, fabrication, and erection of structural steel buildings and other structures shall comply with the Specification. A1.2. High-Seismic Applications (new) When the seismic response modification coefficient, R, is greater than 3, the design, fabrication, and erection of structural steel buildings and other structures shall comply with the requirements in the Seismic Provisions for Structural Steel Buildings, in addition to the provisions in the Specification. A1.3. Nuclear Applications (new) Nuclear structures shall be designed in compliance with Specification for the Design, Fabrication, and Erection of Steel Safety-Related Structures in Nuclear Facilities. A2. REFERENCED SPECIFICATIONS, CODES, AND STANDARDS (was A6) Additional specifications, codes, and standards were included and updated and titles of each are now shown. A3. MATERIAL A3.1. Structural Steel Materials The last paragraph in Section A3.1a in the 1989 Specification was moved into this section. A3.1a. ASTM Designations ASTM specifications were divided into six sections: hot-rolled structural shapes, structural tubing, pipe, plates, bars, and sheets. ASTM A913, A283, A1011 standards were added. Discussion of material testing reports was moved to Section A3.1. A3.1b. Unidentified Steel The condition that unidentified steel is permissible if surface conditions are acceptable according to ASTM A6/A6M was changed from “free of surface imperfections” to “free of injurious defects”. A3.1c. Rolled Heavy Shapes The Heavy Shapes section was divided into Rolled Heavy Shapes (A3.1c) and Built-up Heavy Shapes (A3.1d). It was revised that ASTM A6/A6M hot-rolled shapes with flange thickness greater than 2 in. must be subjected to a Charpy V-Notch impact test in

Transcript of Compare 2005 ASD to 1989 ASD

Page 1: Compare 2005 ASD to 1989 ASD

COMPARISON OF ANSI/AISC 360-05 TO 1989 ASD SPECIFICATION

(prepared by James Falls and Jie Zuo) This document summarizes the revisions made to the ASD provisions contained in the 2005 AISC Specification for Structural Steel Buildings (ANSI/AISC 360-05) compared to the 1989 Specification for Structural Steel Buildings, Allowable Stress Design and Plastic Design.

CHAPTER A GENERAL PROVISIONS

A1. SCOPE

The scope was expanded to include “other structures” in addition to structural steel buildings. Alternate methods of design based on tests and analysis are permitted subject to the approval of the authority having jurisdiction. Paragraphs pertaining to design of single angle members and structural joints were removed. Recommendations for design of cold-formed steel structural members were removed and replaced with a User Note.

A1.1. Low-Seismic Applications (new)

When the seismic response modification coefficient, R, is equal to or less than 3, the design, fabrication, and erection of structural steel buildings and other structures shall comply with the Specification.

A1.2. High-Seismic Applications (new) When the seismic response modification coefficient, R, is greater than 3, the design, fabrication, and erection of structural steel buildings and other structures shall comply with the requirements in the Seismic Provisions for Structural Steel Buildings, in addition to the provisions in the Specification.

A1.3. Nuclear Applications (new) Nuclear structures shall be designed in compliance with Specification for the Design, Fabrication, and Erection of Steel Safety-Related Structures in Nuclear Facilities.

A2. REFERENCED SPECIFICATIONS, CODES, AND STANDARDS (was A6)

Additional specifications, codes, and standards were included and updated and titles of each are now shown.

A3. MATERIAL A3.1. Structural Steel Materials

The last paragraph in Section A3.1a in the 1989 Specification was moved into this section.

A3.1a. ASTM Designations ASTM specifications were divided into six sections: hot-rolled structural shapes, structural tubing, pipe, plates, bars, and sheets. ASTM A913, A283, A1011 standards were added. Discussion of material testing reports was moved to Section A3.1.

A3.1b. Unidentified Steel The condition that unidentified steel is permissible if surface conditions are acceptable according to ASTM A6/A6M was changed from “free of surface imperfections” to “free of injurious defects”.

A3.1c. Rolled Heavy Shapes The Heavy Shapes section was divided into Rolled Heavy Shapes (A3.1c) and Built-up Heavy Shapes (A3.1d). It was revised that ASTM A6/A6M hot-rolled shapes with flange thickness greater than 2 in. must be subjected to a Charpy V-Notch impact test in

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accordance with ASTM A6/A6M, Supplementary Requirement S30, Charpy V-Notch Impact Test for Structural Shapes – Alternate Core Location if it is spliced using complete-joint-penetration (CJP) groove welds that fuse through the thickness of the weld. The reference and exceptions to the ASTM A673/A673A standard procedure for impact testing were removed for rolled shapes.

A3.1d. Built-Up Heavy Shapes (new) It was revised that the Specification requirements apply to built-up cross-sections consisting of plates exceeding 2 in. that are welded with complete-joint-penetration (CJP) groove welds to the face of other sections, formerly “connected by CJP welded joints through the thickness of the thinner material to the face of the heavy material”.

A3.2. Steel Castings and Forgings Cast Steel requirements were changed to conform to ASTM A216/A216M, Gr. WCB with Supplementary Requirement S11. The clause that states “allowable stresses shall be same as those provided for other steels” was removed.

A3.3. Bolts, Washers, and Nuts (was A3.4) This section is now separated into categories Bolts, Nuts, Washers, and Compressible-Washer-Type Direct Tension Indicators. ASTM standards are listed for each material. Provisions restricting the use of A449 bolts were removed.

A3.4. Anchor Rods and Threaded Rods (was A3.5) The terminology “anchor rods” replaces “anchor bolts”. The ASTM A449 standard was added. Permitted use of steel bolts as anchor rods under specified conditions was removed. The User Note, “ASTM F1554 is the preferred material specification for anchor rods,” was added.

A3.5. Filler Metal and Flux For Welding (was A3.6) The paragraph stating that filler metals with a specified Charpy V-Notch toughness shall be used in specified joints was removed.

A3.6. Stud Shear Connectors (was A3.7) Unchanged. The User Note “studs are made from cold drawn bar, either semi-killed or killed aluminum or silicon deoxidized, conforming to the requirements of ASTM A29/A29M-04” was added.

A4. STRUCTURAL DESIGN DRAWINGS AND SPECIFICATIONS (was A7) This section was condensed and it states that design drawings and specifications shall meet the requirements in the Code of Standard Practice for Steel Buildings and Bridges, except for deviations specifically identified in design drawings. Paragraphs pertaining to the required drawing indication of construction types, connection types, camber, and welding were removed.

CHAPTER B

DESIGN REQUIREMENTS B1. GENERAL PROVISIONS (new)

This section states that the design of members and connections shall be consistent with the intended behavior of the framing system and the assumptions made in the structural analysis. Unless restricted by the applicable building code, lateral load resistance and stability may be provided by any combination of members and connections. In the absence of a building code, the provisions specified in SEI/ASCE 7 shall apply instead of ANSI A58.1, which was specified in the 1989 Specification.

B2. LOADS AND LOAD COMBINATIONS (was A4) A User Note was added stating that for ASD designs, load combinations in SEI/ASCE 7, Section 2.4 shall apply. Specifications regarding impact, crane, and environmental loads were removed.

B3. DESIGN BASIS (was A5) Design shall be made according to provisions of Load and Resistance Factor Design (LRFD) or Allowable Strength Design (ASD). B3.1. Required Strength

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This section states that the required strength of members and connections shall be determined by structural analysis for the appropriate load combinations. Provisions for elastic, inelastic, and plastic analysis are referenced.

B3.2. Limit States (was A5.1) This section was reworded and includes serviceability limit states.

B3.3. Design For Strength Using Load And Resistance Factor Design (LRFD) (new) This section states that according to LRFD provisions, the design strength of each structural component must equal or exceed the required strength determined by LRFD load combinations. The equation relationship between design strength and required strength is given.

B3.4. Design For Strength Using Allowable Strength Design (ASD) (new) This section states that according to ASD provisions, the allowable strength of each structural component must equal or exceed the required strength determined by ASD load combinations. The equation relationship between allowable strength and required strength is given.

B3.5. Design For Stability (was B4) This section refers to Chapter C for determining stability.

B3.6. Design Of Connections (was J1.1) This section refers to the provisions in Chapters J and K for connection design.

B3.6a. Simple Connections (was J1.2) This section was reworded for clarity.

B3.6b. Moment Connections (was J1.3) This section was revised such that two types of moment connections, Fully-Restrained (FR) and Partially-Restrained (PR), are permitted.

B3.7. Design for Serviceability (was A5.4) Unchanged.

B3.8. Design for Ponding (was K2) This section now states that roof systems shall be investigated through structural analysis to assure strength and stability under ponding conditions, unless the roof surface is provided with a slope of ¼ in. per ft or greater toward points of free drainage or an adequate system of drainage is provided to prevent accumulation of water. Appendix 2, Design for Ponding, which provides methods of checking ponding, is referenced.

B3.9. Design for Fatigue (was K4) Design for members and their connections subject to repeated loading is referenced to Appendix 3, Design for Fatigue.

B3.10. Design for Fire Conditions (new) This section references Appendix 4, Structural Design for Fire Conditions: Qualification Testing and Engineering Analysis Compliance, which provides two methods of design for fire conditions. Compliance with the fire protection requirements in the applicable building code shall satisfy the requirements in this section and Appendix 4.

B3.11. Design for Corrosion Effects (was L5) Unchanged. B3.12. Design Wall Thickness For HSS (new)

This section specifies the design wall thickness, t, to be taken equal to 0.93 times the nominal wall thickness for electric-resistance-welded (ERW) HSS and equal to the nominal thickness for submerged-arc-welded (SAW) HSS.

B3.13 Gross and Net Area Determination Determination of gross and net areas was combined into one section.

B3.13a. Gross Area (was B1) This section was revised stating that the gross area, of a member, Ag, is the total cross-sectional area.

B3.13b. Net Area (was B2) The net area, An, of a slotted HSS welded to a gusset plate was added.

B4. CLASSIFICATION OF SECTIONS FOR LOCAL BUCKLING (was B5.1) This section references Table B4.1 for determining limiting width-thickness ratios.

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B4.1. Unstiffened Elements (was B5.1) A User Note references Table B4.1 for a graphical representation of unstiffened element

dimensions. B4.2. Stiffened Elements (was B5.1) Paragraphs a, b, c, and d were revised for clarity. A User Note references Table B4.1 for

a graphical representation of stiffened element dimensions. Table B4.1. Limiting Width-Thickness Ratios For Compression Elements (was Table B5.1) The compact and noncompact limits, λp and λr, were introduced. Graphical figures and

numbers were assigned to each case. Descriptions of elements were revised. For example, “flanges of I-shaped welded beams in flexure” was revised to “flexure in flanges of doubly and singly symmetric I-shaped built-up sections.”

Case 1—The description was rephrased. Case 2—Built-up sections were added. I-shapes restricted to singly and doubly

symmetric. Case 3—Uniform compression of I-shaped sections is specified. Flanges of channels

were added. Case 4—Uniform compression of I-shaped sections is specified. Case 5—New case. Uniform compression in legs of single angles, legs of double angles

with separators, and unstiffened elements. Case 6—New case. Flexure in legs of single angles. Case 7—New case. Flexure in flanges of tees. Case 8—Uniform compression is specified. Case 9—Flexure in webs of double symmetric I-shaped sections and channels is

specified. Limiting width-thickness ratio for d/t was removed. Case 10—New case. Uniform compression in webs of doubly symmetric I-shaped

sections. Case 11—New case. Flexure in webs of singly-symmetric I-shaped sections. Case 12—Square box terminology was removed. Case 13—New case. Flexure in webs of rectangular HSS. Case 14—Description was rephrased. Case 15—Uniform compression is specified.

2005 Specification 1989 Specification Case

Width-thickness

ratio λp λr λp λr

1 b/t 0.38 / yE F 1.0 / yE F 65 / yF 95 / yF

2 b/t 0.38 / yE F 0.95 /c Lk E F 65 / yF 95 / /yf cF k

3 b/t — 0.56 / yE F — 95 / yF

4 b/t — 0.64 /c yk E F — 95 / /y cF k

5 b/t — 0.45 / yE F — —

6 b/t 0.54 / yE F 0.91 / yE F — —

7 b/t 0.38 / yE F 1.0 / yE F — —

8 d/t — 0.75 / yE F — 127 / yF

9 h/tw 3.76 / yE F 5.70 / yE F — 760 / bF

10 h/tw — 1.49 / yE F — —

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11 hc/tw ≤ λ⎛ ⎞

−⎜ ⎟⎜ ⎟⎝ ⎠

2

0.54 0.09

c

p yr

p

y

h Eh F

MM

5.70 / yE F — —

12 b/t 1.12 / yE F 1.40 / yE F 190 / yF 238 / yF

13 h/t 2.42 / yE F 5.70 / yE F — —

14 b/t — 1.49 / yE F — 253 / yF

d/t — 0.11 / yE F 3300 / yF — 15 Compression

Flexure d/t 0.07 / yE F 0.31 /E F 3300 / yF —

The following cases were removed:

• Unstiffened elements simply supported along one edge, such as legs of single-angle struts, legs of double-angle struts with separators and cross or star-shaped cross sections.

• Unsupported width of cover plates perforated with a succession of access holes. • Webs in combined flexural and axial compression.

B5. Fabrication, Erection And Quality Control (new)

This section references Chapter M. B6. Evaluation Of Existing Structures (new)

This section references Appendix 5 for provisions for the evaluation of existing structures.

CHAPTER C STABILITY ANALYSIS AND DESIGN (was Frames and Other Structures)

C1. STABILITY DESIGN REQUIREMENTS C1.1. General Requirements (was B4 and C1)

The acceptable stability design methods are now included. The Direct Analysis Method, which is introduced in Appendix 7, will satisfy these requirements. Elastic Design is permitted based on Section C2.2 and the connection design requirements. Inelastic (Plastic) Design shall follow Appendix 1.

C1.2. Member Stability Design Requirements (new) Individual member stability must satisfy the provisions of Chapters E, F, G, H, and I. Bracing requirements are referenced to Appendix 6, Stability Bracing for Columns and Beams.

C1.3. System Stability Design Requirements (new) This section states that lateral stability shall be provided by a lateral load resisting

system. Effects of overturning drift, gravity loads, force sharing and force are considered. C1.3a. Braced-Frame and Shear-Wall Systems (was C2.1)

This section was moved from Section C2.1 from the 1989 Specification and from A5.2a from Supplement No.1. This paragraph was reworded for clarity.

C1.3b. Moment-Frame Systems (was C2.2) This section states that the effective length factor K or elastic critical buckling stress, Fe, shall be determined as specified in Section C2.

C1.3c. Gravity Framing Systems (new) This section states that analysis of gravity framing systems shall be based on actual lengths (K=1.0), and lateral stability shall be provided by moment frames, braced frames, shear walls, and/or other equivalent lateral load resistant systems. Second order effects shall also be transferred to the lateral load resisting system.

C1.3d. Combined Systems (new)

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This section states that all combined systems shall meet the requirements of their respective systems.

C2. CALCULATION OF REQUIRED STRENGTHS (new)

This section states that required strengths shall be computed using a second-order analysis in Section C2.1, except as permitted in Section C2.2b.

C2.1. Methods of Second-Order Analysis (new)

This section states “second-order analysis shall conform to the requirements in this Section.”

C2.1a. General Second-Order Elastic Analysis (new) This section states that any second-order elastic analysis that considers P-Δ and P-δ effects is permitted.

C2.1b. Second-Order Analysis by Amplified First-Order Elastic Analysis (new) This section provides a method to account for second-order effects in frames by

amplifying the axial forces and moments in members and connections from a first-order analysis. Equations for this method are also provided. A list of symbols and their definitions are shown.

C2.2. Design Requirements (new) This section states that if the first-order drift divided by the second-order drift is less than

or equal to 1.5, then first-order and second-order analyses are applicable. If the ratio is larger, one of the methods specified in C2.2a, C2.2b or by the Direct Analysis Method in Appendix 7 shall be used.

C2.2a. Design by Second-Order Analysis (new) This section sets guidelines by which design by second-order analysis shall follow. C2.2b. Design by First-Order Analysis (new) This section sets guidelines by which design by first-order analysis shall follow. It

provides a list of symbols and their definitions.

CHAPTER D DESIGN OF MEMBERS FOR TENSION (was Tension Members)

A User Note was added referencing sections that address cases not covered in this chapter. The term “prismatic member” was removed. D1. SLENDERNESS LIMITATIONS (was B7)

The slenderness ratio limit for compression was removed. A preferred limit of 300 for the slenderness ratio, L/r is suggested in a User Note. Hangers in tension were added as an exception to this suggestion. The clause that states that members designed to perform in tension that experiences some compression loading was removed.

D2. TENSILE STRENGTH (was D1) The definition of allowable tensile strength for yielding in the gross section and rupture in the net section was revised with the introduction of the safety factor of Ωt = 1.67 and Ωt = 2.0, respectively (effectively the same as 0.60Fy and 0.50Fu). The nominal strengths of tensile yielding and rupture are defined as follows: For tensile yielding in the gross section Pn = FyAg (D2-1) For tensile rupture in the net section Pn = Fu Ae (D2-2) The clause about block shear strength referring to another section was removed. References to pin-connected members and eyebars were removed. Cases where effective net area is required are explained and referenced to Equation D2.2 and Section D3.

D3. AREA DETERMINATION D3.1. Gross Area (was B1)

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For all members, the gross area, Ag, was redefined as the member’s total cross-sectional area.

D3.2. Net Area (was B2) Rivet holes were removed from the clause stating “the width of bolt holes shall be 6 in. (2 mm) greater than the nominal dimension of the hole.” The net area of a slotted HSS member welded to a gusset plate is defined. Determination of the critical net area, An, was removed as well as the term itself. A User Note was added that states “Section J4.1(b) limits An to a maximum of 0.85Ag for splice plates with holes.”

D3.3. Effective Net Area (was B3) Terminology for U was changed from “reduction coefficient” to “shear lag factor”. The phrase that states that the net area is equal to the gross area when the load is transmitted by welds was removed. Also, an added provision states that the use of a value of U less than 0.60 is permitted if the tension members are designed for the effect of eccentricity in accordance with Section H1.2 or H2.

Table D3.1. Shear Lag Factors For Connections To Tension Members (was B3) For each element, the table displays a description, its corresponding shear lag factor equation, an example figure, and an assigned case number. Additional elements were added to include round HSS members with a single concentric gusset plate, rectangular HSS members, and single angles. The phrase “in the direction of stress” was replaced with “in the direction of loading”. The terminology “bolts and rivets” was replaced by the term “fasteners”. The term “rivet” was removed entirely. If a calculated U value is less than the value produced by the equation in Case 2, then the latter shall be used for W, M, S, or HP shapes or Tees cut from these shapes. The phrase stating that a shear lag factor of U = 0.75 shall be used for all members having only two fasteners per line in the direction of stress was removed.

D4. BUILT-UP MEMBERS (was D2)

Maximum longitudinal spacing of connectors between elements in continuous contact was referenced to Section J3.5. Restrictions on longitudinal spacing of fasteners and intermittent welds connecting two or more shapes in contact were removed. The slenderness ratio limitation was inserted into a User Note.

D5. PIN-CONNECTED MEMBERS (was D3) D5.1. Tensile Strength

The allowable stress on the net area of the pin hole for pin-connected members has changed from 0.45Fy to the lower value obtained according to the limit states of tensile rupture, shear rupture, bearing, and yielding. For tensile rupture on the net effective area: 2n eff uP tb F= (D5-1) For shear rupture on the net effective area: 0.6n u sfP F A= (D5-2)

For bearing on the projected area of the pin, see Section J7. For yielding on the gross section, use Equation D2-1. D5.2. Dimensional Requirements (was D3.2)

Net area restrictions were removed. Dimensional requirements were removed and plate width restrictions were included.

D6. EYEBARS (was D3.3) D6.1. Tensile Strength (was D3.1)

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The term “allowable stress”, which is defined as 0.60Fy on the body area, was redefined as “available tensile strength”, which is determined in accordance with Section D2, with Ag taken as the area of the body.

D6.2. Dimensional Requirements (was D3.3) Unchanged.

CHAPTER E

DESIGN OF MEMBERS FOR COMPRESSION (was Columns and Other Compression Members)

A User Note references members not included in this chapter to other sections. E1. GENERAL PROVISIONS (new)

The allowable compressive strength Pn/Ωc is determined by the lowest nominal compressive strength value, Pn, obtained according to the limit states of flexural, torsional, and flexural-torsional buckling, where Ωc = 1.67. Types of members that apply to certain limit states are specified.

E2. SLENDERNESS LIMITATIONS AND EFFECTIVE LENGTH (was E1)

A User Note was added which states that the slenderness ratio, KL/r, should preferably not exceed 200 for members designed for compression.

E3. COMPRESSIVE STRENGTH FOR FLEXURAL BUCKLING OF MEMBERS WITHOUT

SLENDER ELEMENTS (was E2) The allowable compressive strength is Pn/Ωc, where Pn = FcrAg and Ωc = 1.67 (Equation E3-1). The flexural buckling stress, Fcr, is calculated instead of the allowable stress, Fa. The safety factor, Ωc, replaces the built-in safety factors in the 1989 Specification. The 2005 Specification is also based on a different column curve. The symbol for the length term has changed from “l” to “L”.

Case 1989 Specification 2005 Specification Defined limit between elastic and inelastic

buckling

⎛ ⎞⎜ ⎟= =⎜ ⎟⎝ ⎠

π 22 4.44cy y

E ECF F

4.71y

EF

≤ cKL Cr

( )

( ) ( )

⎡ ⎤−⎢ ⎥

⎢ ⎥⎣ ⎦=

+ −

2

2

3

3

/1

2

3 / /53 8 8

c c

yc

a

KL rF

CF

KL r KL rC C

(E2-1)

≤ 4.71y

KL Er F

or

≥ 0.44e yF F —

⎡ ⎤

= ⎢ ⎥⎣ ⎦0.658

ye

FF

cr yF F

(E3-2)

> cKL Cr

( )=

2

212π

23 /aEF

KL r

(E2-2)

> 4.71y

KL Er F

or

< 0.44e yF F —

= 0.877cr eF F (E3-3)

The elastic critical buckling stress is defined by

2

=⎛ ⎞⎜ ⎟⎝ ⎠

eEF

KLr

(E3-4)

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in the 2005 Specification. A User Note indicates that when torsional unbraced length is larger than the lateral unbraced length, Section E4 may control the design of W shapes and similar columns.

E4. COMPRESSIVE STRENGTH FOR TORSIONAL AND FLEXURAL-TORSIONAL BUCKLING

OF MEMBERS WITHOUT SLENDER ELEMENTS (was E3) This section contains provisions for torsional and flexural-torsional buckling. There were no provisions in

the 1989 Specification. The equation for nominal compressive strength is defined as well as the equations for the flexural buckling stress for double-angles and tee-shaped members. For all other cases, equations for the elastic buckling stress, Fe, are provided to be used in conjunction with Fcr as defined in Section E3 for doubly symmetric, singly symmetric, and unsymmetric members. A User Note provides a simplified equation for the warping constant, Cw, for doubly symmetric I-shaped sections. It also provides a simplified approach for calculating Fez for tees and double angles.

E5. SINGLE ANGLE COMPRESSION MEMBERS (new) Nominal compressive strength shall be determined in accordance with Section E3 or Section E7, as

appropriate. For special conditions, the effects of eccentricity can be neglected and equations for effective KL/r values are provided.

E6. BUILT-UP MEMBERS (was E4) E6.1. Compressive Strength (new)

This section was broken down into two parts, members composed of two or more shapes that are interconnected by bolts or welds and members with at least one open side interconnected by perforated cover plates or lacing with tie plates.

E6.2. Dimensional Requirements (was E4) References to other sections for spacing and edge distance requirements for weathering steel members were removed. The following provisions were added. End connections shall be welded or pretensioned bolted with Class A or B faying surfaces. At the ends of built-up compression members bearing on base plates or milled surfaces, all components in contact with one another shall be connected by a weld with a specified length not less than the maximum width of the member. The factor that is multiplied by the thickness of the outside plate to determine the maximum bolt spacing was non-dimensionalized. Cover plates may substitute lacing with tie plates on open-sided built-up members. The inclination of lacing bars was inserted into a User Note.

E7. MEMBERS WITH SLENDER ELEMENTS (was Appendix B5.2c) Similar to Section E3, the flexural buckling strength is defined instead of the allowable stress.

Case 1989 Specification 2005 Specification Defined limit between elastic and inelastic

buckling

π ⎛ ⎞= =⎜ ⎟

⎝ ⎠

2' 2 4.44c

y y

E ECQF QF

4.71y

EQF

≤ 'c

KL Cr

( )

( ) ( )

⎡ ⎤−⎢ ⎥

⎢ ⎥⎣ ⎦=

+ −

2

' 2

3

' ' 3

/1

2

3 / /53 8 8

c c

yc

a

KL rQ F

CF

KL r KL rC C

(A-B5-11)

≤ 4.71y

KL Er QF

or

≥ 0.44e yF QF —

⎡ ⎤

= ⎢ ⎥⎣ ⎦0.658

ye

QFF

cr yF Q F

(E7-2)

> 'c

KL Cr

( )π

=2

212

23 /aEF

Kl r

(A-B5-12) —

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> 4.71y

KL Er QF

or

< 0.44e yF QF —

= 0.877cr eF F (E7-3)

The elastic critical buckling stress, Fe, and Q are defined. A User Note elaborates on how Q is calculated.

E7.1 Slender Unstiffened Elements, Qs (was Appendix B5.2a)

The width-thickness limits and reduction factor equations were non-dimensionalized by factoring out E.

Flanges, angles or plates projecting from columns or other compression members

Case 1989 Specification 2005 Specification

≤ 0.56y

b Et F

— = 1.0sQ

(E7-4)

Rolled Columns

< <0.56 1.03y y

E b EF t F

Rolled Columns ⎛ ⎞= − ⎜ ⎟⎝ ⎠

1.415 0.74 ys

FbQt E

(E7-5)

Built-up Columns

< <0.64 1.17c c

y y

Ek b EkF t F

Built-up Columns ⎛ ⎞= − ⎜ ⎟⎝ ⎠

1.415 0.65 ys

c

FbQt Ek

(E7-8)

< <95.0 195

y y

c c

btF F

k k

⎛ ⎞= − ⎜ ⎟⎝ ⎠1.293 0.00309 y

sc

FbQt k

(A-B5-3)

Rolled Columns

≥ 1.03y

b Et F

Rolled Columns

( )= 2

0.69s

y

EQbF t

(E7-6)

Built-up Columns

≥ 1.17 c

y

b Ekt F

Built-up Columns

=⎛ ⎞⎜ ⎟⎝ ⎠

20.90 c

s

y

EkQbFt

(E7-9)

>195

y

c

bt F

k

( )= 2

26,200 cs

y

kQbF t

(A-B5-4) —

Single Angles

Case 1989 Specification 2005 Specification

≤ 0.45y

b Et F

— = 1.0sQ

(E7-10)

< ≤0.45 0.91y y

E b EF t F

— ⎛ ⎞= − ⎜ ⎟⎝ ⎠

1.34 0.76 ys

FbQt E

(E7-11)

< <76.0 155

y y

btF F

( )= −1.340 0.00447s ybQ Ft

(A-B5-1) —

> 0.91y

b Et F

— ( )= 2

0.53s

y

EQbF t

(E7-12)

Page 11: Compare 2005 ASD to 1989 ASD

≥155

y

bt F

( )= 2

15,500s

y

QbF t

(A-B5-2) —

Stems of tees

Case 1989 Specification 2005 Specification

≤ 0.75y

d Et F

— = 1.0sQ

(E7-13)

< ≤0.75 1.03y y

E d EF t F

— ⎛ ⎞= − ⎜ ⎟⎝ ⎠

1.908 1.22 ys

FdQt E

(E7-14)

< <127 176

y y

btF F

( )= −1.908 0.00715s ybQ Ft (A-

B5-5) —

> 1.03y

d Et F

— ( )= 2

0.69s

y

EQdF t

(E7-15)

≥176

y

bt F

( )= 2

20,000s

y

QbF t

(A-B5-6) —

E7.2 Slender Stiffened Elements, Qa (was Appendix B5.2b and Appendix B5.2c)

Uniformly compressed slender elements, except flanges of square and

rectangular sections of uniform thickness Case 1989 Specification 2005 Specification

≥ 1.49b Et f

⎡ ⎤= − ≤⎢ ⎥

⎣ ⎦

0.341.92 1eE Eb t bf b t f

(E7-17)

>95

y

bt F

( )⎡ ⎤

= − ≤⎢ ⎥⎢ ⎥⎣ ⎦

253 44.31etb b

f b t f

(A-B5-8)

Flanges of square and rectangular slender-element sections of uniform thickness Case 1989 Specification 2005 Specification

≥ 1.40b Et f

⎡ ⎤= − ≤⎢ ⎥

⎣ ⎦

0.381.92 1eE Eb t bf b t f

(E7-18)

>238

y

bt F

( )⎡ ⎤

= − ≤⎢ ⎥⎢ ⎥⎣ ⎦

253 50.31etb b

f b t f

(A-B5-7)

Axially-loaded circular sections

Case 1989 Specification 2005 Specification

< <0.11 0.45y y

E D EF t F

— ( )= = +

0.038 23a

y

EQ QF D t

(E7-19)

< <3,000 13,000

y y

DF t F

= +662 0.40a yF FD t

(A-B5-9) —

Page 12: Compare 2005 ASD to 1989 ASD

A User Note was added that facilitates the calculation of f. The reduction factor, Qa, for axially-loaded circular sections is also added. Wind and seismic loading were removed from this section.

CHAPTER F DESIGN OF MEMBERS FOR FLEXURE (was Beams And Other Flexural Members)

Method for distinguishing beams from plate girders was removed. References to other sections pertaining to shear strength were removed. Applicable members subject to this chapter were generalized to “simple bending about one principal axis”. A User Note was added that references other chapters for members not covered in this chapter. The term “hybrid member” was removed. The sections were categorized by symmetry, compactness, and/or axis at which member is bent. Previously in the 1989 Specification, the sections were organized by member shapes and unbraced length. F1. GENERAL PROVISIONS (was F1.3 and B6)

The nominal flexural strength, Mn, safety factor for flexure, Ωb = 0.90, and allowable flexural strength, Mn/Ωb, are defined. The lateral-torsional buckling modification factor, Cb, for nonuniform moment is defined, and a revised equation for calculating Cb is introduced. Restrictions to lateral-torsional buckling strength of singly symmetric members are made. A User Note provides provisions to Equation F1-1 for doubly symmetric members with no transverse loading. 1989 Specification

2

1 1

2 2

1.75 1.05 0.3bM MCM M

⎛ ⎞ ⎛ ⎞= + +⎜ ⎟ ⎜ ⎟

⎝ ⎠ ⎝ ⎠

2005 Specification

max

max

12.5 3.02.5 3 4 3b m

A B C

MC RM M M M

= ≤+ + +

(F1-1)

F2. DOUBLY SYMMETRIC COMPACT I-SHAPED MEMBERS AND CHANNELS BENT ABOUT

THEIR MAJOR AXIS (was F1) A User Note lists members that do not have compact flanges. Moment reduction proportioning were

moved into Appendix 1 of the 2005 Specification. F2.1. Yielding (was F1.1)

The nominal flexural strength based on the yielding limit state is calculated using Equation F2-1. The plastic section modulus, Zx, is introduced.

F2.2. Lateral-Torsional Buckling (was F1.3) The lateral-torsional buckling limit state is introduced. Limiting lengths equations for Lp and Lr are introduced, and variable Lc was removed. Equations for nominal lateral-torsional buckling strength are provided for various conditions regarding the unbraced length Lb. Equation for critical lateral-torsional buckling strength is also shown. A User Note allows for a conservative assumption when calculating Fcr. Another User Note suggests an approximation of rts as the radius of gyration of the compression flange plus one-sixth of the web in the calculation for the limiting length, Lr.

F3. DOUBLY SYMMETRIC I-SHAPED MEMBERS WITH COMPACT WEBS AND NONCOMPACT

OR SLENDER FLANGES BENT ABOUT THEIR MAJOR AXIS (was F1.2) A User Note lists shapes with noncompact flanges for Fy = 50 ksi. F3.1. Lateral-Torsional Buckling The provisions of Section F2.2 apply.

Page 13: Compare 2005 ASD to 1989 ASD

F3.2. Compression Flange Local Buckling Equations for the nominal strength of sections with noncompact and slender flanges are provided.

F4. OTHER I-SHAPED MEMBERS WITH COMPACT OR NONCOMPACT WEBS BENT ABOUT

THEIR MAJOR AXIS (was F1) This section replaces portions of Section F1. It is noted that the nominal flexural strength, Mn, shall be the lowest value obtained according to limit states of compression flange yielding, lateral-torsional buckling, compression flange local buckling, and tension flange yielding. F4.1. Compression Flange Yielding The nominal compression flange yield strength is calculated using Equation F4-1. F4.2. Lateral-Torsional Buckling

Nominal lateral-torsional buckling strengths are provided for various Lb conditions. Under specific provisions, the torsional constant, J, may be taken as zero. The limiting laterally unbraced length for limit states of yielding, Lp, and inelastic lateral-torsional buckling, Lr, is provided. The web plastification factor, Rpc, is introduced.

F4.3. Compression Flange Local Buckling Nominal strengths for local buckling are given. F4.4. Tension Flange Yielding

Tension flange yielding is a new limit state. Nominal strengths for tension flange yielding under various conditions are given.

F5. DOUBLY SYMMETRIC AND SINGLY SYMMETRIC I-SHAPED MEMBERS WITH SLENDER

WEBS BENT ABOUT THEIR MAJOR AXIS (was G2) The nominal flexural strength, Mn, shall be the lowest value obtained according to the limit states of

compression flange yielding, lateral-torsional buckling, compression flange local buckling and tension flange yielding.

F5.1. Compression Flange Yielding

Equation F5-1 was introduced to calculate the nominal compression flange yield strength. F5.2. Lateral-Torsional Buckling

For different unbraced length conditions, equations for the lateral-torsional buckling critical strength, Fcr, are provided. The bending strength reduction factor is introduced and the equation is provided.

F5.3. Compression Flange Local Buckling For several compactness conditions, the nominal flange local buckling strength equation is provided.

F5.4. Tension Flange Yielding The equation for nominal flange yielding strength is given for

Sxt < Sxc.

F6. I-SHAPED MEMBERS AND CHANNELS BENT ABOUT THEIR MINOR AXIS (was F2) The nominal flexural strength, Mn, shall be the lowest value obtained according to the limit states of flange

yielding and flange local buckling. F6.1. Yielding

Equation F6-1 was introduced to calculate the nominal yield strength of members pertaining to this section.

F6.2. Flange Local Buckling The equations for nominal flange local buckling strength are provided for noncompact flanges and slender flanges. Yielding shall apply to sections with compact flanges. A User Note lists shapes with slender flanges.

F7. SQUARE AND RECTANGULAR HSS AND BOX-SHAPED MEMBERS (was F3.1)

Page 14: Compare 2005 ASD to 1989 ASD

This section applies to members bent about either axis, having compact or noncompact webs and compact, noncompact, or slender flanges. Depth and flange thickness restrictions for compact box-shaped members were removed. Lateral bracing provisions were removed from this section. F7.1. Yielding

Equation F7-1 was introduced to calculate the nominal yield strength of square and rectangular HSS members.

F7.2. Flange Local Buckling For sections with noncompact flanges and slender flanges, the equations for nominal flange local buckling strength are provided. This limit state does not apply to compact sections. The effective section modulus, Seff, is introduced.

F7.3. Web Local Buckling For sections with noncompact webs, the equation for nominal flange local buckling strength is provided.

F8. ROUND HSS (was F3)

This section applies to round HSS members having D/t ratios of less than 0.45E/Fy. The nominal flexural strength, Mn, shall be the lower value obtained according to the limit states of yielding and local buckling. F8.1. Yielding

Equation F8-1 was introduced to calculate the nominal yield strength of round HSS members.

F8.2. Local Buckling Equations for nominal local buckling strength are provided for noncompact and slender sections. This limit state does not apply to compact sections. A User Note lists shapes with slender flanges.

F9. TEES AND DOUBLE ANGLES LOADED IN THE PLANE OF SYMMETRY (new)

The nominal flexural strength, Mn, shall be the lower value obtained according to the limit states of yielding, lateral-torsional buckling, and flange local buckling. F9.1. Yielding

Mn = Mp (F9-1) where

Mp = FyZx ≤ 1.6My (for stems in tension) (F9-2) Mp ≤ My (for stems in compression) (F9-3)

F9.2. Lateral-Torsional Buckling The equation for nominal lateral-torsional buckling strength is provided. A negative B value shall be used if the tip of the stem is in compression anywhere along the unbraced length.

F9.3. Flange Local Buckling of Tees The general equation for nominal flange local buckling strength of tees is provided.

F10. SINGLE ANGLES (new)

Design on the basis of geometric design bending is permitted if the member has continuous lateral-torsional restraint along the length. The nominal flexural strength, Mn, shall be the lower value obtained according to the limit states of yielding, lateral-torsional buckling, and leg local buckling. F10.1. Yielding

Equation F10-1 was introduced to calculate single angle yield strength. F10.2. Lateral-Torsional Buckling

A new equation for nominal lateral-torsional buckling strength is provided. F10.3. Leg Local Buckling

This limit state applies when the toe of the leg is in compression and the section is noncompact or slender. New equations for nominal leg local buckling strengths are introduced.

Page 15: Compare 2005 ASD to 1989 ASD

F11. RECTANGULAR BARS AND ROUNDS (was F2) The nominal flexural strength, Mn, shall be the lower value obtained according to the limit states of yielding

and lateral-torsional buckling. F11.1. Yielding

New equations for nominal strengths for major and minor axis bending are introduced. A restriction on rectangular bars bent about their major axis was added.

F11.2. Lateral-Torsional Buckling For various rectangular bar sizes, new equations were introduced to calculate the nominal lateral-torsional buckling strength. This limit state does not apply to rounds and rectangular bars bent about their minor axis.

F12. UNSYMMETRICAL SHAPES (new)

This section applies to all unsymmetrical shapes excluding single angles. The nominal flexural strength, Mn, shall be the lower value obtained according to the limit states of yielding, lateral-torsional buckling, and local buckling. F12.1. Yielding

Equation F12-2 was introduced to calculate the yield strength of unsymmetrical shapes. F12.2. Lateral-Torsional Buckling

Equation F12-3 was introduced to calculate the lateral-torsional buckling strength of unsymmetrical shapes.

F12.3. Local Buckling Equation F12-4 was introduced to calculate the local buckling strength of unsymmetrical shapes.

F13. PROPORTIONS OF BEAMS AND GIRDERS F13.1. Hole Reductions (was B10)

1989 Specification 2005 Specification Proportioning ≥For 0.5 0.6u fn y fgF A F A

(B10-1) — No deductions made

— ≥For u fn t y fgF A Y F A Tensile rupture does not apply

<For 0.5 0.6u fn y fgF A F A (B10-2)

— =

56

ufe fn

y

FA AF

(B10-3)

— <For u fn t y fgF A Y F A = u fnn x

fg

F AM SA

(F13-1)

F13.2. Proportioning Limits For I-Shaped Members (was G1) Singly symmetric I-shaped members must satisfy a restriction regarding moment of inertia.

Case 1989 Specification 2005 Specification No stiffeners or

> 1.5ah

( )≤

+

14,000

16.5w yf yf

ht F F

(G1-1)

For ≤ 1.5ah

2,000

w yf

ht F

(G1-2)

⎛ ⎞=⎜ ⎟⎝ ⎠max

11.7w y

h Et F

(F13-3)

Page 16: Compare 2005 ASD to 1989 ASD

For > 1.5ah

— ⎛ ⎞

=⎜ ⎟⎝ ⎠max

0.42

w y

h Et F

(F13-4)

No stiffeners — ≤ 260w

ht

F13.3. Cover Plates (was B10) Unchanged. F13.4 Built-Up Beams (was F6)

The connection interval restriction of 5 feet was removed. When two or more beams or channels are used side-by-side to form a flexural member, they shall be connected according to Section E6.2. The use of through-bolts and separators is no longer permitted.

CHAPTER G

DESIGN OF MEMBERS FOR SHEAR (was F4)

Design for members for shear now has a chapter of its own. This chapter addresses webs of singly or doubly symmetric members subject to shear in the plane of the web, single angles, and HSS sections, and shear in the weak direction of singly or doubly symmetric shapes. A User Note indicates member sections not covered. G1. GENERAL PROVISIONS

The symbol for shear, Vn, was introduced. The safety factor for shear is Ωv = 1.67, except for webs of rolled I-shaped members with the provisions in G2.1a. This section provides two methods to calculate shear strength. One utilizes the post buckling strength of a member (tension field action), and the other does not. The 1989 Specification references Chapter G for utilizing tension field action.

G2. MEMBERS WITH UNSTIFFENED OR STIFFENED WEBS G2.1. Nominal Shear Strength

Case 1989 Specification 2005 Specification

For ≤380

y

ht F

= 0.40v yF F (F4-1)

For >380

y

ht F

= ≤ 0.402.89

yv v y

FF C F

(F4-2) —

All — = 0.6n y w vV F A C (G2-1)

These ratios were non-dimensionalized. Cv values are calculated based on the h/tw ratio. The web plate buckling coefficient, kv, is calculated for stiffened and unstiffened webs.

Case 1989 Specification 2005 Specification

For < 0.8vC ( )= 2

45,000/

vv

y w

kCF h t

For > 0.8vC =190/

vv

w y

kCh t F

For ≤/ 1.10 /w v yh t k E F — Cv = 1.0 (G2-3)

For ≤ ≤1.10 / / 1.37 /v y w v yk E F h t k E F

— =

1.10 //

v yv

w

k E FC

h t

(G2-4)

Page 17: Compare 2005 ASD to 1989 ASD

For >/ 1.37 /w v yh t k E F — ( )= 2

1.51/

vv

w y

EkCh t F

(G2-5)

For </ 1.0a h ( )= + 2

5.344/vk

a h —

For >/ 1.0a h ( )= + 2

45.34/vk

a h —

For unstiffened webs with </ 260wh t — kv = 5 kv = 1.2 for stems of tees

For >/ 3.0 or a h ( )⎛ ⎞

> ⎜ ⎟⎝ ⎠

2260// w

a hh t

— kv = 5.0

All other cases — ( )= + 2

55/vk

a h

A list of sections for which Cv = 1.0 was added in a User Note. G2.2. Transverse Stiffeners (was F5 and G4) Transverse stiffeners are required when:

1989 Specification 2005 Specification >/ 260wh t >/ 2.46 /w yh t E F

AND max shear stress fv is greater than that permitted by

Equation F4-2

OR when required shear strength is greater than the available shear

strength G3. TENSION FIELD ACTION

G3.1. Limits on the Use of Tension Field Action (new) This section lists conditions under which tension field action is not permitted.

G3.2. Nominal Shear Strength with Tension Field Action (was G3)

G3.3. Transverse Stiffeners (was G4) Limitations were added to transverse stiffeners subject to tension field action.

G4. SINGLE ANGLES (new) This section provides the nominal shear strength of single angles using tension field action.

G5. RECTANGULAR HSS AND BOX MEMBERS (new)

Case 1989 Specification

If provisions of Section G4 and Cv ≤ 1.0 ( )

⎡ ⎤−⎢ ⎥= + ≤⎢ ⎥+⎣ ⎦

2

1 0.402.89 1.15 1 /

y vv v y

F CF C Fa h

(G3-1)

Case 2005 Specification

For ≤/ 1.10 /w v yh t k E F = 0.6n y wV F A (G3-1)

For >/ 1.10 /w v yh t k E F ( )

⎛ ⎞−⎜ ⎟= +⎜ ⎟+⎝ ⎠

2

10.61.15 1 /

vn y w v

CV F A Ca h

(G3-2)

Page 18: Compare 2005 ASD to 1989 ASD

This section provides a new equation along with other provisions to calculate the nominal shear strength of rectangular HSS and box members.

G6. ROUND HSS (new) This section provides a new equation to calculate the nominal shear strength according to the limit states of shear yielding and shear buckling.

G7. WEAK AXIS SHEAR IN SINGLY AND DOUBLY SYMMETRIC SHAPES (new) This section contains provisions to calculate the nominal shear strength of these member sections. A User Note lists shapes with Cv = 1.0.

G8. BEAMS AND GIRDERS WITH WEB OPENINGS (new) This section states that adequate reinforcement shall be provided when the required strength exceeds the available strength of the member at the opening.

CHAPTER H DESIGN OF MEMBERS FOR COMBINED FORCES AND TORSION (was Combined Stresses)

The chapter now includes unsymmetric sections. H1. DOUBLY AND SINGLY SYMMETRIC MEMBERS SUBJECT TO FLEXURE AND AXIAL

FORCE

H1.1. Doubly and Singly Symmetric Members in Flexure and Compression (was H1) A User Note adds that Section H2 is permitted to be used in lieu of the provisions from this section.

Case 1989 Specification Interaction Equations

+ + ≤⎛ ⎞ ⎛ ⎞− −⎜ ⎟ ⎜ ⎟⎝ ⎠ ⎝ ⎠

' '

1.01 1

my bya mx bx

a a abx by

ex ey

C ff C fF f fF FF F

(H1-1)

All

AND + + ≤ 1.00.60

bya bx

y bx by

ff fF F F

(H1-2)

If ≤ 0.15a

a

fF

+ + ≤ 1.0bya bx

a bx by

ff fF F F

(H1-3)

Case 2005 Specification Interaction Equations

For ≥ 0.2r

c

PP

⎛ ⎞

+ + ≤⎜ ⎟⎝ ⎠

8 1.09

ryr rx

c cx cy

MP MP M M

(H1-1a)

For < 0.2r

c

PP

⎛ ⎞

+ + ≤⎜ ⎟⎝ ⎠

1.02

ryr rx

c cx cy

MP MP M M

(H1-1b)

H1.2. Doubly and Singly Symmetric Members in Flexure and Tension (was H2) For doubly symmetric members, Cb may be increased by

1 u

ey

PP+

The former interaction Equation H2-1 was removed. H1.3. Doubly Symmetric Members in Single Axis Flexure and Compression (new) New limit states “in-plane instability” and “out-of-plane buckling” were added along

with their respective interaction equations.

Page 19: Compare 2005 ASD to 1989 ASD

H2. UNSYMMETRIC AND OTHER MEMBERS SUBJECT TO FLEXURE AND AXIAL FORCE (new)

A new interaction equation which is very similar to Equation H1-3 from the 1989 Specification was introduced. The new equation states that if the axial force is compression, second order effects shall be included.

H3. MEMBERS UNDER TORSION AND COMBINED TORSION, FLEXURE, SHEAR AND/OR

AXIAL FORCE (new)

H3.1. Torsional Strength of Round and Rectangular HSS (new) The equation for nominal torsional strength is defined for round and rectangular HSS

members. Equations that yield conservative values for the torsional shear constant, C, were added.

H3.2. HSS Subject to Combined Torsion, Shear, Flexure, and Axial Force (new) A new interaction equation shall be used if the required torsional strength, Tr, exceeds

20% of Tc. H3.3 Strength of Non-HSS Members Under Torsion and Combined Stress (new) This section provides the allowable torsional strength, Fn/ΩT according to the limit states

of yielding under normal stress, shear yielding under shear stress, or buckling.

CHAPTER I DESIGN OF COMPOSITE MEMBERS (was Composite Construction)

Filled and concrete-encased composite columns composed of rolled or built-up structural steel shapes or HSS are now addressed. I1. GENERAL PROVISIONS (new)

The design, detailing, and material properties related to the concrete and reinforcing steel portions of composite construction shall comply with the reinforced concrete and reinforcing bar design specifications stipulated by the applicable building code or the provisions in ACI 318 in the absence of the building code. I1.1. Nominal Strength of Composite Sections (new)

This section provides two methods for determining the nominal strength of composite section: the plastic stress distribution method and the strain-compatibility method. The tensile strength of the concrete shall be neglected.

I1.1a. Plastic Distribution Method (new) This section states that the nominal strength shall be computed under the assumption that steel components have reached their yield stress in either tension or compression and concrete components in compression have reached a stress of 0.85f′c. For round HSS filled with concrete, a stress of 0.95f′c is permitted to be used if the concrete components are in uniform compression.

I1.1b. Strain Compatibility Method (new) This method assumes a linear distribution of strains across the section. A User Note points out that this method should be used to determine nominal strength for irregular sections.

I1.2. Material Limitations (new) This section imposes material property restrictions on concrete and steel.

I1.3. Shear Connectors (was I4) This section defines minimum shear connector length and the acceptable material (refers to Sections A3.1 and A3.6). Shear stud design values are referenced to Sections I2.1g and I3.2d(3).

I2. AXIAL MEMBERS (new)

This section applies to two types of composite axial members, encased and filled sections. I2.1. Encased Composite Columns (new)

Page 20: Compare 2005 ASD to 1989 ASD

I2.1a. Limitations (new) This section defines limitations that must be met in order to qualify as an encased composite column.

I2.1b. Compressive Strength (new) Allowable compressive strength shall be determined according to the flexural buckling limit state.

I2.1c. Tensile Strength (new) The allowable tensile strength shall be determined according to the yielding limit state. A new nominal tensile strength equation is introduced.

I2.1d. Shear Strength (new) The available shear strength shall be calculated based on either the shear strength of the steel section alone plus the shear strength provided by the tie reinforcement or the shear strength of the reinforced concrete alone. A User Note adds the equation for the nominal shear strength of the tie reinforcement and references ACI 318, Chapter 11 for the shear capacity of reinforced concrete.

I2.1e. Load Transfer (new) Depending on whether the external force is applied to the steel section, concrete encasement, or concrete, the shear connectors shall be required to transfer shear force, V’. New equations are introduced to calculate the shear force.

I2.1f. Detailing Requirements (new) Shear connector spacing requirements are defined in this section.

I2.1g. Strength of Stud Shear Connectors (was I4) This section provides an equation for the nominal strength of a stud shear connector.

I2.2 FILLED COMPOSITE COLUMNS (new) I2.2a. Limitations (new)

Limitations that must be met in order to qualify as a filled composite column are defined in this section.

I2.2b. Compressive Strength (new) The allowable compressive strength for axially loaded filled composite columns shall be determined according to the flexural buckling limit state.

I2.2c. Tensile Strength (new) The allowable tensile strength shall be determined according to the yielding limit state. A new equation for nominal tensile strength equation is introduced.

I2.2d. Shear Strength (new) The available shear strength shall be calculated based on either the shear strength of the steel section alone plus the shear strength provided by the tie reinforcement or the shear strength of the reinforced concrete alone. A reference to ACI 318, Chapter 11 on the topic of shear strength of reinforced concrete is provided in a User Note.

I2.2e. Load Transfer (new) This section states that the force transfer mechanism providing the largest nominal strength may be used. A new equation for nominal bearing strength is introduced.

I2.2f. Detailing Requirements (new) Shear connector spacing is defined. I3. FLEXURAL MEMBERS I3.1. General Unchanged. I3.1a. Effective Width (was I1)

Editorial changes were incorporated. I3.1b. Shear Strength (new)

The available shear strength of composite beams with shear connectors, concrete-encased, and filled composite flexural members is stipulated.

I3.1c. Strength During Construction (was I2)

Page 21: Compare 2005 ASD to 1989 ASD

The clause that states “stresses in the steel section shall not exceed 0.90Fy” was removed. When temporary shores are not used during construction, the steel section alone shall have adequate strength prior to the concrete attaining 75% of its specified strength, f′c.

I3.2. Strength of Composite Beams with Shear Connectors Unchanged. I3.2a. Positive Flexural Strength (was I2)

Case 1989 Specification 2005 Specification Composite Beam Fb = 0.66Fy — Steel Beam Alone Fb = 0.76Fy —

For ≤/ 3.76 /w yh t E F — Mn shall be determined from the plastic stress distribution for yielding

For >/ 3.76 /w yh t E F — Mn shall be determined from the

superposition of elastic stresses for yielding

I3.2b. Negative Flexural Strength (new)

The allowable negative flexural strength shall be determined according to Chapter F. Alternatively, under a few restrictions, the available negative flexural strength can be determined from the plastic stress distribution for the yielding limit state.

I3.2c. Strength Of Composite Beams With Formed Steel Deck (was I5) The provision stating that shall be at least ½ in. of concrete cover above the top of the

installed shear studs was added. The maximum spacing was increased from 16 to 18 in. Limitations on stud shear connector spacing on supporting beams were removed. Allowable horizontal shear load reduction factor was removed for both orientations (perpendicular and parallel) of the deck ribs with respect to steel beam or girder.

I3.2d. Shear Connectors (was I4) The limit states for load transfer for positive moment were defined as concrete crushing, tensile yielding of the steel section, and strength of the shear connectors, with the lowest value controlling.

Limit State 1989 Specification 2005 Specification Concrete Crushing = '0.85 / 2h c cV f A (I4-1) = '' 0.85 c cV f A (I3-1a)

Tensile yielding of steel = / 2h y sV F A (I4-2) =' y sV F A (I3-1b) Positive Moment

Strength of connectors =hV nq = ∑' nV Q (I3-1c)

Tensile yielding of slab = / 2h yr srV F A (I4-3) =' yr rV F A (I3-2a) Negative Moment Strength of connectors =hV nq = ∑' nV Q (I3-2b)

The horizontal shear equations apply to half the span in the 1989 Specification and the full span in the 2005 Specification. This is why the equation is no longer divided by two. The equations for the nominal strength of one stud shear connector and one channel shear connector were added. The effective moment of inertia equation was removed. The equation for the number of shear connectors required between any concentrated load in that area and the nearest point of zero moment was removed. Minimum center-to-center spacing of shear connectors shall be four diameters in any direction when the ribs of the formed steel decks are oriented perpendicular to the steel beam. Maximum center-to-center spacing of shear connectors shall not exceed eight times the slab thickness nor 36 in. (the latter was new in the 2005 Specification). The maximum stud diameter limit does not apply if it is located on the web.

I3.3 Flexural Strength Of Concrete-Encased And Filled Members (new) This section stipulates the flexural strength of concrete-encased and filled members.

Three methods are shown.

Page 22: Compare 2005 ASD to 1989 ASD

I4. COMBINED AXIAL FORCE AND FLEXURE (new) This section contains provisions on composite members with combined axial force and flexure.

I5. SPECIAL CASES (was I6)

This section states that when composite construction does not conform to the provisions in this chapter, strength of shear connectors and details of construction (added since the 2005 Specification) shall be established by testing.

CHAPTER J

DESIGN OF CONNECTIONS J1. GENERAL PROVISIONS

J1.1. Design Basis The effects of eccentricity shall now be considered where the gravity axes of intersecting axially loaded members do not intersect at one point.

J1.2. Simple Connections The meaning of inelastic deformation is explained by adding, “self-limiting deformation in the connection is permitted to accommodate the end rotation of a simple beam.”

J1.3. Moment Connections Response criteria for moment connections are now provided in Section B3.6b.

J1.4. Compression Members With Bearing Joints The clause, “all compression joints shall be proportional to resist any tension developed by the specified lateral loads acting in conjunction with 75% of the calculated dead-load stress and no live load,” was removed. It is now permissible to use “the moment and shear resulting from a transverse load equal to 2% of the required compressive strength of the member,” when compression members other than columns are finished to bear at splices.

J1.5. Splices In Heavy Sections (was J1.7) A full-penetration groove weld was renamed as a complete-joint-penetration groove weld. In the 1989 Specification, the clause stating “welding preheat requirements as given in J2.7” in paragraph two and paragraphs three and five were removed. The clause, “the foregoing provision is not applicable to splices of elements of built-up shapes that are welded prior to assembling the shape,” was added to the 2005 Specification. A User Note was added explaining the detrimental effects of weld shrinkage for CJP groove welded splices at heavy sections and PJP groove welds on the flanges and fillet-welded web plates.

J1.6. Beam Copes And Weld Access Holes (was J1.8) The access hole height requirement is now defined as 1½ times the thickness of the material with the access hole, tw, but not less than 1 in., nor does it exceed 2 in. Also, no arc of the weld access hole shall have a radius of less than a in. The reference to Group 4 and 5 shapes was deleted in the last paragraph. Several requirements on the preparation of weld access holes and beam copes were revised.

J1.7. Placement Of Welds And Bolts (was J1.9) Rivets are excluded from the 2005 Specification. The last sentence of the first paragraph in the 1989 Specification, which refers to the eccentricity of statically loaded members, was deleted. The note “See Sect. J3.10 for placement of fasteners in built-up members made of weathering steel” was also removed.

J1.8. Bolts In Combination With Welds (was J1.10) Bolts shall not share the load with welds except for shear connections when bolts are installed in standard holes or short slots transverse to the direction of the load, if they are designed to share the load with a longitudinally loaded fillet weld. The available strength of the bolts in such connections shall not exceed 50% of the available strength of bearing-type bolts in the connection.

J1.9. High Strength Bolts In Combination With Rivets (was J1.11)

Page 23: Compare 2005 ASD to 1989 ASD

This section added the clarification that the design provisions for slip-critical connections are included in Section J3.

J1.10. Limitations On Bolted And Welded Connections (was J1.12) This section now lists four different connections that must use pretensioned joints, slip-critical joints, or welds. Column splices in all multi-story structures over a height of 200 ft was changed to over 125 ft. The definition of a “tier structure” and related terminology was deleted. Also, the provision that, “any other connections stipulated on the design plans,” should use fully-tensioned high-strength bolts or welds was deleted.

J2. WELDS All provisions from AWS D1.1 still apply to this section with the exception of certain specified sections.

J2.1. Groove Welds

J2.1a. Effective Area Table J2.1 was expanded. Different welding positions now correspond to unique groove types and a unique effective throat dimension. Table J2.2 includes flare bevel and flare V groove welds and was renamed “Effective Weld Sizes of Flare Groove Welds.” Also, the weld sizes listed in the table are now listed by welding process instead of the type of weld. Table J2.3 is now based on the thinner part of the material being joined not the thicker.

J2.1b. Limitations The throat thickness of a partial-joint-penetration groove weld must now be thick enough to transmit calculated forces.

J2.2. Fillet Welds J2.2a. Effective Area

An increase in effective throat is now permitted if consistent penetration beyond the root of the diagrammatic weld is demonstrated by tests using the production process and procedure variables. The clause “except that for fillet welds made by the submerged arc process, the effective throat thickness shall be taken equal to the leg size for a in. and smaller fillet welds, and equal to the theoretical throat plus 0.11 in. for fillet welds larger than a in.” was removed.

J2.2b. Limitations Minimum fillet weld sizes must not be less than the size required to transmit the calculated force. The provisions of this section do not apply to fillet weld reinforcement of partial or complete-joint-penetration groove welds. Table J2.4 was modified. The minimum fillet weld size is now based on the thinner of the two parts being joined, not the thicker. Also, if the end-loaded fillet weld exceeds 100 times the weld size, the effective length shall be determined by multiplying the actual length by the reduction factor, β, which is defined by Equation J2-1. If the weld size exceeds 300 times the leg size, the value of β shall be 0.60. Provisions for fillet weld terminations are revised and listed.

J2.3. Plug And Slot Welds J2.3a. Effective Area Unchanged. J2.3b. Limitations Unchanged. J2.4. Strength

The allowable strength of welds shall be the lower value of the base metal and the weld metal strength based on the limit states of tensile rupture, shear rupture, and yielding. These values can be calculated using Equations J2-2 and J2-3 and Table J2.5. Table J2.5 now lists φ and Ω, and nominal strengths instead of allowable stresses. Three loading conditions for fillet welds were added: (a) Linear weld group loaded in-plane through the center of gravity. Equations J2-4 and

J2-5 were introduced.

Page 24: Compare 2005 ASD to 1989 ASD

(b) Weld elements within a weld group that are loaded in plane and analyzed using an instantaneous center of rotation method. Equations J2-6, J2-7, and J2-8 were introduced.

(c) Fillet welds concentrically loaded and consisting of elements that are oriented both longitudinally and transversely to the direction of applied load. Equations J2-9a and J2-9b were introduced.

J2.5. Combination Of Welds Unchanged. J2.6. Filler Metal Requirements (new)

Requirements for filler metals shall comply with AWS D1.1 and this section. The manufacture’s Certificate of Conformance is sufficient evidence of compliance.

J2.7. Mixed Weld Metal (was J2.6) The term “notch-toughness” was replaced with “Charpy V-Notch toughness”.

J3. BOLTS AND THREADED PARTS Rivets were deleted from the title.

J3.1. High Strength Bolts Table J3.7, Minimum Pretension for Fully-tightened Bolts, in the 1989 Specification was moved into this section and is now Table J3.1, Minimum Bolt Pretension. This section now explicitly requires that A325 and A490 bolts be tightened to a minimum bolt tension given in Table J3.1. Table J3.2, Allowable Stress on Fasteners, was modified and is now called, “Nominal Stress of Fasteners and Threaded Parts. The table now lists nominal tensile and shear stress in bearing-type connections instead of allowable tension and shear stresses. Shear strength provisions for slip-critical conditions were removed from the table. Table J3.1, Nominal Hole Dimensions, in the 1989 Specification is now Table J3.3. All joint surfaces shall now be free of scale except tight mill scale. All ASTM A325, A325M, A490, and A490M must be tightened in accordance with Table J3.1 or J3.1M. A nut may be tightened using the turn-of-nut method, a direct tension indicator, calibrated wrench, or alternative design bolt unless the bolts are permitted to be installed as snug tight in bearing-type connections and tension or combined shear applications. If ASTM A490 or A490M bolts over 1 in. are used in oversized holed or external piles a hardened washer in conformance with ASTM F436 must be used. Adequate strength must be available in slip-critical connections. When bolts exceed the size and length requirements provided by ASTM A325 and A325M, F1852, or ASTM 490 and ASTM 490M, bolts and threaded rods are permitted to be used based on the provisions provided in Table J3.2 and conforming to ASTM A354 Gr. BC, A354 Gr. BD or A449. The last sentence of this section in the 1989 Specification requiring a ASTM F436 hardened washer to be installed under the bolt head if the bolt is required to be tightened more than 50% of the minimum bolt tensile strength was removed.

J3.2. Size And Use Of Holes Short-slotted holes parallel to the load or long-slotted holes are now allowed if they are approved by the Engineer of Record. The last paragraph of this section in the 1989 Specification, which describes washer requirements for A490 bolts over 1-in. diameter, was deleted.

J3.3. Minimum Spacing (was J3.8) A center-to-center distance of three times the diameter of the bolt is now preferred. Equation J3-5 in the 1989 Specification and Table J3.4, Values of Spacing Increment C1, were removed.

J3.4. Minimum Edge Distance (was J3.9) Table J3.5, Minimum Edge Distance, (Center of Standard Hole to Edge of Connected Part) in the 1989 Specification is now Table J3.4, Minimum Edge Distance, from Center of Standard Hole to Edge of Connected Part. This distance may be calculated using the tables or as required by Section J3.10.

J3.5. Maximum Spacing And Edge Distance (was J3.10)

Page 25: Compare 2005 ASD to 1989 ASD

For painted or unpainted members not subject to corrosion, the provision that spacing shall not exceed 24 times the thickness of the thinner plate or 12 in. (305 mm) is new. Also, the max edge distance requirement for unpainted built-up members of weathering steel exposed to atmospheric corrosion was deleted.

J3.6. Tension And Shear Strength Of Bolts And Threaded Parts (was J3.4) This section modified the section “Allowable Tension and Shear.” The allowable tension or shear strength for a snug-tight or pretensioned bolt or threaded part for limit states of tensile rupture and shear rupture may now be calculated using Equation J3-1. Tensions and shear strength values were revised in Table J3.2. The table below compares the allowable stress values based on the two specifications.

Comparison of Table J3.2 between the 1989 and 2005 Specification

1989 Specification 2005 Specification 1989 Specification 2005 Specification

Description of Fasteners Allowable Tension, Ft, ksi

Allowable Tensile Stress, Fnt / Ω, ksi

Bearing Type Connections, Fv, ksi

Allowable Shear Stress in Bearing-Type Connections,

Fnv/ Ω, ksi

A502, Gr. 1 hot-driven rivets 23 — 17.5 —

A502, Gr. 2 and 3, hot-driven rivets 29 — 22 —

A307 bolts 20 22.5 10 12

A325 or A325M bolts, when threads are not excluded from shear planes 44 45 21 24

A325 or A325M bolts, when threads are excluded from shear planes 44 45 30 30

A490 or A490M bolts, when threads are not excluded from shear planes 54 56.5 28 30

A490 or A490M bolts, when threads are excluded from shear planes 54 56.5 40 37.5

Threaded parts meeting the requirements of Section A3.4, when threads are not excluded from shear

planes

0.33Fu 0.375Fu 0.17Fu 0.20Fu

Page 26: Compare 2005 ASD to 1989 ASD

J3.7. Combined Tension And Shear In Bearing-Type Connections (was J3.5) A set of equations is provided in the 2005 Specification to calculate the available tensile

strength of a bolt subject to the limit states of tension and shear rupture. In the 1989 Specification, shear and tension were checked independently against the shear and tension allowable strengths. The 3 stress increase for wind and seismic loading was removed. Table J3.3, Allowable Tension Stress, Ft for Fasteners in Bearing-Type Connections was removed.

J3.8. HIGH Strength Bolts In Slip-Critical Connections (new) This section allows high-strength bolts in slip-critical connections to be designed to prevent slip as either a serviceability or a required strength limit state. Equation J3-4 is used to calculate the design slip-resistance.

J3.9. Combined Tension And Shear In Slip-Critical Connections (was J3.6) If a slip-critical connection is subjected to an applied tension that reduces the net

clamping force, the available slip should be multiplied by the factor ks. Equations J3-5a and J3-5b are used to calculate this factor instead of the reduction factor offered in the 1989 Specification. The equations are listed below:

1989 Specification

Reduction factor 1 t b

b

f AT

⎛ ⎞= −⎜ ⎟⎝ ⎠

where Ab = bolt cross-sectional area at its major thread diameter Ft = average tensile stress due to a direct load applied to all to

bolts in the connection Tb = pretension load of the bolt specified in Table J3.7

2005 Specification

1 5

us

u b B

. Tk

D T N=

where Nb = number of bolts carrying the applied tension Ta = tension force due to ASD load combinations, kips (kN) Tb = minimum fastener tension given in Table J3.1, kips (kN) Tu = tension force due to LRFD load combinations, kips (kN) J3.10. Bearing Strength At Bolt Holes (was J3.7) Equations J3-6a, J3-6b, and J3-6c are used to calculate the available bearing strength

depending on the type of connection being designed. Upper strength limits were added to each of these equations. The equations are now based on the area, Lct, instead of the projected area of bolts. The distance from the free edge to the center of the bolt, Le, was replaced by Lc, the clear distance between the edge of the hole and the next adjacent hole or the edge of the material. The minimum limit on end distance and bolt spacing was removed.

J3.11. Special Fasteners (new) The nominal strength of all special fasteners not listed in Table J3.2 must be verified by

testing.

Threaded parts meeting the requirements of Section A3.4, when

threads are excluded from shear planes

0.33Fu 0.375Fu 0.22Fu 0.25Fu

Page 27: Compare 2005 ASD to 1989 ASD

J3.12. Tension Fasteners (new) This section refers to bolts or other fasteners that attach to an unstiffened box or HSS

Wall. The strength of the wall shall be determined by rational analysis.

J4. AFFECTED ELEMENTS OF MEMBERS AND CONNECTING ELEMENTS (was J5) Stiffeners and panel zones were removed from the list of applicable connecting elements. J4.1. Strength Of Elements In Tension New Equations J4-1 and J4-2 were developed to calculate the allowable strength for

connecting elements subjected to the limit states of tensile yielding and tensile rupture. J4.2. Strength Of Elements In Shear

New Equations J4-3 and J4-4 were developed to calculate the available shear yield strength for connecting elements subjected to the limit states of shear yielding and shear rupture.

J4.3. Block Shear Strength New Equation J4-5 was developed to calculate the available strength for connecting

elements subjected to the limit state of block shear rupture. J4.4. Strength Of Elements In Compression New Equation J4-6 was developed to calculate the available strength of connecting

elements for connecting elements subjected to the limit state of yielding and buckling.

J5. FILLERS (was J6) A new provision for the case where the fillers are equal to or less than ¼ in. thick was introduced. Items 2, 3, and 4 are new requirements.

J6. SPLICES (was J7) This section was reworded for clarity. J7. BEARING STRENGTH (was J8)

This section modified the “Allowable Bearing Stress” section in the 1989 Specification. Two different equations are provided for expansion rollers and rockers based on the diameter to calculate the allowable bearing strength for the limit state of bearing (local compressive yielding).

J8. COLUMN BASES AND BEARING ON CONCRETE (was J9)

New nominal strength Equations J8-1 and J8-2 were developed to calculate the allowable bearing strength for connecting elements subjected to the limit state of concrete crushing. Provisions for masonry were deleted.

J9. ANCHOR RODS AND EMBEDMENTS (was J10)

This section was previously called, “Anchor Bolts.” Detail was added to the section for clarity. All rods should be designed in accordance with Table J3.2.

J10. FLANGES AND WEBS WITH CONCENTRATED FORCES (was K1)

A statement indicating the application of the limit states, either single or double concentrated forced, is explained. J10.1. Flange Local Bending (was K1.2)

The allowable strength for the limit state of flange local bending is calculated using Equation J10-1 instead of K1-1. The provision that allows the computed force to be multiplied by 5/3 or 4/3 depending on the load case was removed. If the concentrated force is applied at a point less than 10 times the thickness of the flange, the design strength may now be reduced by 50%.

J10.2. Web Local Yielding (was K1.3) Equations J10-2 and J10-3 are rearranged versions of Equations K1-2 and K1-3, excluding the 0.66Fy limit.

J10.3. Web Crippling (was K1.4)

Page 28: Compare 2005 ASD to 1989 ASD

The equations are non-dimensionalized by factoring out the modulus of elasticity in Equations K1-4 and K1-5, which are now Equations J10-4, J10-5a, and J10-5b. When the compressive force is applied at a distance that is less than the depth of the member divided by 2, and the length of bearing divided by the overall depth of the member is less than or equal to 0.2, the available strength is calculated using J10-5a. If the length of bearing divided by the overall depth of the member is greater than 0.2, the available strength is calculated using J10-5b.

J10.4. Web Sideway Buckling (was K1.5) Equations J10-6 and J10-7 are modified versions of Equations K1-6 and K1-7 providing higher allowable strength.

J10.5. Web Compression Buckling (was K1.6) A new equation is introduced. Also, a 50% reduction in available strength is required when compressive forces are located at a distance less than d/2 from the member’s end.

J10.6. Web Panel Zone Shear (was K1.7) A set of equations were developed to calculate the available strength of a panel zone based on the limit state of shear yielding.

J10.7. Unframed Ends Of Beams And Girders (was K1.8) A pair of stiffeners must be provided at unframed ends of beams and girders if they are not restrained against rotation about their longitudinal axis.

J10.8. Additional Stiffener Requirements For Concentrated Forces (was K1.8) This section was reorganized for clarity. Stiffeners designed to resist tensile forces shall

now be designed in accordance with Chapter D and stiffeners designed to resist compressive forces shall be designed in accordance with Sections E6.2 and J4.4. Equation K1-9 was deleted. A new provision states that the thickness of a stiffener shall not be greater than or equal to the width divided by 15.

J10.9. Additional Doubler Plate Requirements For Concentrated Forces (new) This section refers to the design of doubler plates, which shall be designed in accordance

with Chapter E, D, and G as well as special criteria given on the thickness of the doubler plate and the weld required to develop the proportion of the total force transmitted to the doubler plate.

CHAPTER K

DESIGN OF HSS AND BOX MEMBER CONNECTIONS (new) This chapter discusses the strength design considerations for HSS members and box sections of uniform wall thickness that are used to make connections.

CHAPTER L DESIGN FOR SERVICEABILITY

L1. GENERAL PROVISIONS

Serviceability shall now be evaluated based on the appropriate load combinations for the serviceability limit state identified. The section was reworded for clarity.

L2. CAMBER

The provisions that trusses spanning 80 ft or more must be cambered based on the dead load and that crane girders spanning 75 ft or more must be cambered based on the dead load and half the live load were removed. Also, the provision that beams and trusses without specified camber shall be fabricated so that after erection the camber due to rolling or shop assembly shall be upward was removed. Camber involving preload is not required to be noted in the design documents.

L3. DEFLECTIONS (was L3.1)

Deflections of structural members shall not impair the serviceability of the structure based on the service load combinations is a new provision. A maximum live-load deflection of 1/360 over the length of the span for beams and girders was removed.

Page 29: Compare 2005 ASD to 1989 ASD

L4. DRIFT (new) Drift will be evaluated under service loads to protect the integrity of interior and exterior partitions and shall not cause collision with an adjacent structure or exceed the drift limits that may be specified in the applicable building code.

L5. VIBRATION (was L3.2)

Vibration due to pedestrian walking, vibrating machinery, and others identified for the structure must now be considered.

L6. WIND-INDUCED MOTION (new)

This section states that a wind-induced motion must not affect the comfort of a building’s occupants.

L7. EXPANSION AND CONTRACTION (was L2) Damage from expansion or contraction to the cladding should now be considered to avoid water penetration that may cause corrosion.

L8. CONNECTION SLIP

The effects of connection slip should now be included in the design of the connection to avoid deformations that impair the serviceability of the structure. When appropriate, connections should be designed to preclude slip.

CHAPTER M

FABRICATION, ERECTION AND QUALITY CONTROL M1. SHOP DRAWINGS This section was reworded for clarity. M2. FABRICATION

M2.1. Cambering, Curving, And Straightening The provision that limits the temperature to 1050 °F of a heated area for A852 steel was increased to 1100 °F. The temperature limits for A709 steel were removed.

M2.2. Thermal Cutting All thermally cut edges must now meet the requirements of AWS D1.1. Galvanized beam copes and weld access holes shall now be ground. A new provision states that all shapes with a flange thickness not exceeding a thickness of 2 in. shall have a surface toughness no greater than 2,000 μin. Any crack found is unacceptable.

M2.3. Planing Of Edges Unchanged. M2.4. Welded Construction

Exceptions to AWS D1.1 requirements for weld workmanship, quality, and appearance are now acceptable if they are in accordance with Section J2.

M2.5. Bolted Construction Bolt holes should now comply with the provisions of the RCSC Specification for Structural Joints Using ASTM A325 or A490 Bolts, Section 3.3 with the exception that the bolt hole roughness should not exceed 1,000 μin. All provisions referring to the manner at which holes are made in the material were removed. Slope requirements for parts in contact with the bolt head and the nut are no longer applicable. Also, limitations on scale, burrs, and coatings on the surface of connected parts were removed. Gouges shall now not exceed a depth of 6 in.

M2.6. Compression Joints Unchanged. M2.7. Dimensional Tolerances Unchanged. M2.8. Finish Of Column Bases

Page 30: Compare 2005 ASD to 1989 ASD

The provision that all column bases other than rolled steel bearing plates shall be milled for all bearing surfaces was removed.

M2.9. Holes For Anchor Rods (new) This section allows anchor rods to be thermally cut in accordance with Section M2.2.

M2.10. Drain Holes (new) This section requires all HSS members to be sealed and provided with a drain hole or protected by some other means if water can collect inside the member.

M2.11. Requirements For Galvanized Members (new) This section requires that any galvanized member be designed, detailed, and fabricated to prevent pressure build-up in enclosed parts.

M3. SHOP PAINTING M3.1. General Requirements

Steelwork is no longer required to be painted unless noted on the contract documents. M3.2. Inaccessible Surfaces Unchanged. M3.3. Contact Surfaces Unchanged. M3.4. Finished Surfaces Unchanged. M3.5. Surfaces Adjacent To Field Welds Unchanged. M4. ERECTION M4.1. Alignment Of Column Bases Unchanged. M4.2. Bracing

It is no longer a provision to account for stresses resulting from piles, material erection equipment, or other loads during erection.

M4.3. Alignment Unchanged.

M4.4. Fit Of Column Compression Joints And Base Plates Unchanged. M4.5. Field Welding A new provision states that field welding of attachments to installed embedments in

contact with concrete shall be done to prevent excessive thermal expansion. M4.6. Field Painting Unchanged.

M4.7. Field Connections Unchanged. M5. QUALITY CONTROL M5.1. Cooperation Unchanged. M5.2. Rejections Unchanged. M5.3. Inspection Of Welding

The inspection of welding can now be modified if in accordance with Section J2. If visual inspection of welds is required, it must now be specified in the design documents.

M5.4. Inspection Of Slip-Critical High –Strength Bolted Connections Unchanged. M5.5. Identification Of Steel

Page 31: Compare 2005 ASD to 1989 ASD

It is no longer required to verify proper material applications relating to material specification designation, heat number, or material test reports when identifying steel.

APPENDIX 1 (new)

INELASTIC ANALYSIS AND DESIGN

This appendix provides provisions for inelastic analysis and design. Some of these provisions, such as the redistribution of moments (from Section F1.1), existed in the 1989 Specification in other sections.

APPENDIX 2 (new) DESIGN FOR PONDING

This appendix includes 1989 Section K2 provisions and discusses the design of a roof for ponding effects.

2.1. SIMPLIFIED DESIGN FOR PONDING

The simplified design method for ponding can be found in section K2 of the 1989 Specification. The method and equations are unchanged.

2.2. IMPROVED DESIGN FOR PONDING (new)

This section gives provisions that may be used if a more exact determination of framing stiffness is required.

APPENDIX 3

DESIGN FOR FATIGUE (was Appendix K) 3.1. GENERAL (was K4)

Fatigue was originally defined as the “damage that may result in fracture after a sufficient number of fluctuations of stress.” The definition was changed to the “limit state of crack initiation and growth resulting from repeated application of live load.” The stress range should now be calculated from the point of probable crack initiation. Other provisions were added that should be taken into consideration when designing for fatigue. Table A-K4.1, Number of Loading Cycles, in the 1989 Specification was removed. Table A-K4.2, Type and Location of Material was renamed, Table A-3.1, Fatigue Design Parameters, and was expanded to include the Constant, Cf, (used in the design equations), the threshold stress value, and the potential crack initiation point.

3.2. CALCULATION OF STRESSES AND STRESS RANGES (new) This section discusses the calculated stresses, maximum stresses, and stress ranges based on an elastic analysis.

3.3. DESIGN STRESS RANGE (was Appendix K4.2) This section allows for the calculation of a design stress range that is computed with newly developed equations instead of Table A-K4.3 in the 1989 Specification. Table A-K4.3 was removed from the 2005 Specification.

3.4. BOLTS AND THREADED PARTS (was Appendix K4.3) Equation A-3-6 is now used to calculate the net tensile forced on a bolt or threaded part instead of the provisions in the 1989 Specification.

3.5. SPECIAL FABRICATION AND ERECTION REQUIREMENTS (new) This section discusses special fatigue provisions.

APPENDIX 4 (new) STRUCTURAL DESIGN FOR FIRE CONDITIONS

This appendix discusses the design and evaluation of structural steel components, systems, and frames for fire conditions.

Page 32: Compare 2005 ASD to 1989 ASD

APPENDIX 5 (new)

EVALUATION OF EXISTING STRUCTURES

This appendix discusses the strength and stiffness of existing structures by structural analysis, load tests, or by a combination of the two when specified by the engineer of record.

APPENDIX 6 (new)

STABILITY BRACING FOR COLUMNS AND BEAMS This appendix addresses the minimum brace strength and stiffness necessary to provide member strengths based on unbraced length with an effective length factor, K, equal to 1.0.

APPENDIX 7 (new) DIRECT ANALYSIS METHOD

This appendix addresses the direct analysis method to account for second order effects in structural systems comprised of moment frames, braced frames, shear walls, or combinations thereof.

CHAPTERS, SECTIONS, TABLES, AND APPENDICES REMOVED FROM 1989 SPECIFICATION

CHAPTERS: Chapter N - Plastic Design

SECTIONS: A2. Limits of Applicability A3.3. Rivets

B5.2. Slender Compression Elements B8. Simple Spans B9. End Restraint B11. Proportioning of Crane Girders E5. Pin-Connected Compression Members E6. Column Web Shear F7. Web-Tapered Members I3. End Shear

J1.5. Connections of Tension and Compression Members in Trusses J1.6. Minimum Connections J2.4. Allowable Stresses J2.7. Preheat for Heavy Shapes J3.3. Effective Bearing Area J3.11. Long Grips J4. Allowable Shear Rupture L5. Corrosion

TABLES: Table I4.1. Allowable Horizontal Shear Load for One Connector

Table I4.2. Coefficients for Use with Concrete made with C330 Aggregates APPENDICES:

Appendix F - Beams and Other Flexural Members