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Geotechnical Engineering Report

Texas Plumbing Supply Red Iron and Pipestone

Schertz, Comal County, Texas

Prepared for: J & J Simpatico, LLC San Antonio, Texas

Prepared by: Drash Consultants, LLC

San Antonio, Texas September 23, 2016

Drash Project No. 116G1178

mailto:[email protected]

TABLE OF CONTENTS Page

EXECUTIVE SUMMARY ........................................................................................................... i INTRODUCTION ...................................................................................................................... 1

Authorization ................................................................................................................. 1 Purpose and Scope of Services .................................................................................... 1

PROJECT INFORMATION ....................................................................................................... 1 SITE AND SUBSURFACE CONDITIONS ................................................................................ 2

Site Conditions .............................................................................................................. 2 Subsurface Conditions .................................................................................................. 2

Subsurface Stratigraphy ............................................................................................................ 2 Subsurface Water ...................................................................................................................... 3

GEOTECHNICAL RECOMMENDATIONS AND GUIDELINES ................................................ 3 Floor Slab System (Flat Slab) ....................................................................................... 4 Forklift Traffic ................................................................................................................ 5 Spread or Strip Footings ............................................................................................... 6

Construction Considerations ...................................................................................................... 7 Drilled Piers .................................................................................................................. 7 Seismic Design Considerations ................................................................................... 11 Corrosion Considerations ............................................................................................ 12 Landscape Design ...................................................................................................... 12 Drainage Adjacent to Structures ................................................................................. 12 Utility Trenches ........................................................................................................... 12 Earthwork .................................................................................................................... 14

General Site Preparation .........................................................................................................14 Building Pad Preparation .........................................................................................................15 Excavation & Replacement with Select Fill .............................................................................15 Vertical Moisture Barrier (VMB) ...............................................................................................16 Bathtub Condition ....................................................................................................................17 Clay Cap ..................................................................................................................................18 Fill Materials and Placement ....................................................................................................18

Pavements .................................................................................................................. 19 Pavement Section Materials ....................................................................................................21 Pavement Joints, Reinforcement, and Dowels ........................................................................23

INTERPRETATION OF REPORT ........................................................................................... 24 CONSTRUCTION MONITORING AND TESTING .................................................................. 24 LIMITATIONS OF REPORT ................................................................................................... 24 EXHIBITS

Exhibit 1 Project Location Map Exhibit 2 Boring Location Plan Exhibit 3 Vertical Moisture Barrier (VMB) Detail Exhibits 4 to 7 Logs of Borings

APPENDIX – FIELD AND LABORATORY Exploratory Drilling Program Laboratory Testing Program Notes Regarding Soil and Rock

Drash Project No. 116G1178 Texas Plumbing Supply Schertz, Comal County, Texas

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EXECUTIVE SUMMARY

This Geotechnical Engineering Report (Report) has been prepared for the design and construction of a new office/warehouse building (Project). The Project is located on the southwest corner of Red Iron and Pipestone approximately 1-mile northwest of IH-35 in Schertz, Comal County, Texas. The single story office/warehouse building will have a footprint of about 39,000 square feet (sf). The building will be a concrete tilt-wall building with interior steel columns and a “dock high” grade supported floor slab. The new development will also include pavement areas for truck access, loading/unloading and for office/staff parking.

Based on the information provided to us for this study and from data developed as part of our engineering service, the site is suitable for the planned improvements. A general summary of our findings, conclusions, and recommendations with regard to the geotechnical engineering aspects of the Project are provided below:

• Subsurface conditions consist of high plasticity clay soils.

• The warehouse floor slab will be grade supported. The tilt-wall panel structures will rest on perimeter grade beams supported by drilled piers or strip footings. The interior steel columns of the building will be supported by isolated spread footings or drilled piers. The strip footings will be supported on a vertical moisture barrier (VMB).

• Key design information is as follows:

o The subsurface stratigraphy exhibits a high potential for volume changes (expansion and contraction) with fluctuations in its moisture content.

o The subsoils, in their current state, yield a Potential Vertical Rise (PVR) of about 3½ to 4 inches.

o Prior to floor slab construction, the warehouse building pad shall be prepared as discussed in the Earthwork section.

o The perimeter grade beam may be supported by strip footings or drilled piers. The perimeter grade beam can be sized for a net allowable bearing pressure of 5,000 psf for dead load plus gravity live load conditions.

o The estimated settlement beneath the foundation units, provided proper and quality construction is performed, is estimated to be less than 1 inch.

• Pavement recommendations are provided for both asphalt and concrete sections.

This summary is provided for convenience only. For those individuals and entities that may need more details or technical information from this report for their use, it must be read in its entirety to have an understanding of the information and recommendations provided for the Project.


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GEOTECHNICAL ENGINEERING REPORT TEXAS PLUMBING SUPPLY RED IRON AND PIPESTONE

SCHERTZ, COMAL COUNTY, TEXAS

INTRODUCTION

Drash Consultants, LLC (Drash) is pleased to submit this geotechnical engineering report for the design and construction of a new office/warehouse building (Project). The Project is located on the southwest corner of Red Iron and Pipestone approximately 1-mile northwest of IH-35 in Schertz, Comal County, Texas. The single story office/warehouse building will have a footprint of about 39,000 square feet (sf). The building will be a concrete tilt-wall building with interior steel columns and a “dock high” grade supported floor slab. The new development will also include pavement areas for truck access, loading/unloading and for office/staff parking.

Authorization

This Project was authorized by Mr. Jim Moore with J & J Simpatico, LLC (Client) on August 30, 2016 by acceptance of our Agreement for Services, No. PG1161230, dated August 30, 2016.

Purpose and Scope of Services

The purposes of this engineering service were to evaluate the general subsurface conditions (soil, rock, subsurface water) within the Project limits by drilling exploratory borings, conduct tests on samples recovered during drilling of the exploratory borings, analyze and evaluate the test data, perform engineering analyses using the data analyzed and evaluated from the field and laboratory programs to develop geotechnical engineering recommendations and guidelines with respect to:

• Site conditions as applicable • Earthwork as applicable

• Subsurface stratigraphy • Foundation design and construction

• Subsurface water conditions • Estimate of foundation settlement

• Potential for soil expansion-contraction • Pavements

PROJECT INFORMATION

The following information was provided to us by the Client, design professionals working on the Project, or was collected by our firm:

Project Location The Project is located on the southwest corner of Red Iron and Pipestone approximately 1-mile northwest of IH-35 in Schertz, Texas. The general vicinity of the Project is illustrated on Exhibit 1, the Project Location Map.


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Project

• Based on information provided to us, we understand that the Project will involve design and construction of an approximately 39,000 sf. office/ warehouse building.

• Associated pavement drives and parking areas are also planned for the project.

• The building will be concrete tilt-wall panels supported by grade beams founded on either drilled pier or strip footing foundations with interior columns and a “dock high” grade supported floor slab.

Current Site Conditions The Project site is currently undeveloped acreage and consists of light vegetation across the overall property.

Current Topography Based on the visual observation, the overall site is sloping down from the southeast to the northwest with approximately 7 to 8 feet of topographic relief across the site.

Proposed Topography

Proposed grades and the finished floor elevation (FFE) were not available to us at the time this report was prepared. For our recommendations, we have assumed that the FFE will be at or near the existing grades. Drash should be contacted to re-evaluate the recommendations, once the FFE becomes available.

SITE AND SUBSURFACE CONDITIONS

Site Conditions

The site, as noted previously, is an undeveloped tract and consists of light vegetation. Based on visual observations, there were no noticeable or obvious conditions within the site that would affect the geotechnical engineering aspects of this Project.

Subsurface Conditions

Subsurface conditions within the Project limits were evaluated by drilling exploratory borings at the locations shown on Exhibit 2, Boring Location Plan. Information retrieved from the exploratory borings is summarized herein.

Subsurface Stratigraphy Subsurface stratigraphy, based on the exploratory borings, can be generalized as follows:

Layer Identification

Approximate Depth To and Thickness Of Layer

(feet) Description of Layer

Layer 1 0 – 35 FAT CLAY (CH); very dark brown, dark brown, light brown with gray mottling, light brown, gray and very dark gray; medium stiff to hard; with ferrous stains

The logs of borings, presenting more specific information about the subsurface stratigraphy encountered at the exploratory boring locations, are provided in the Exhibits section of this report.


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Subsurface Water

Subsurface water was not encountered during drilling or upon completion of the exploratory borings below existing ground surface (ground surface at the time of our field activities). Each exploratory boring was then backfilled with the spoils generated during our drilling operations.

Subsurface water is generally encountered as a ‘true’ or permanent water source or as a ‘perched’ or temporary water source. Permanent subsurface water is generally present year round, which may or may not be influenced by seasonal and climatic changes. Temporary subsurface water generally develops as a result of seasonal and climatic conditions.

Based on the planned development and the site topography, subsurface water may be expected to affect the construction of drilled piers and possible the utilities and vertical moisture barrier.

GEOTECHNICAL RECOMMENDATIONS AND GUIDELINES

Based on the information provided to us by the Client and Project Team, our exploratory borings at the site, results of laboratory tests performed on samples recovered during the subsurface exploration program, and our engineering analyses, the following statements can be made regarding the Project site:

• The site is suitable for the planned construction.

• Proposed grades and the FFE were not available to us at the time this report was prepared. For our recommendations, we have assumed that the FFE will be at or near the existing grades. Drash should be contacted to re-evaluate the recommendations, once the FFE becomes available.

• The subsurface stratigraphy exhibits a high potential for volume changes (expansion and contraction) with fluctuations in its moisture content.

• The tilt-wall panel structures will rest on perimeter grade beams supported by the drilled piers or perimeter strip footings. If a perimeter strip footings option is selected, the footing will need to be supported on a vertical moisture barrier (VMB).

• The interior steel columns of the building will be supported by isolated spread footings or drilled piers.

• The tilt-wall panel structures will either rest on perimeter grade beams supported by drilled piers or rest directly on the drilled piers. If the tilt-wall panels are supported by perimeter grade beams spanning between drilled piers, the grade beams will need to be on 6-inch void boxes. If the tilt-wall panels are supported directly by the drilled piers, 6-inch void boxes should still be used under the panels between the piers.

• A “dock high” grade supported slab may be used provided that the building pad is prepared as discussed in the Building Pad Preparation section of this report.

• Flexible (asphaltic concrete overlying granular base) and rigid (concrete) pavements can be used to support parking and driveway areas.


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The foundations being considered must be designed to reduce the possibility of soil failure when subjected to axial and lateral load conditions. The foundations must also be designed so that foundation movements, whether vertical, horizontal or rotational, are within allowable limits of the soil and within design and operational limits of the proposed structures.

The following geotechnical recommendations and guidelines have been prepared based on the data collected or developed during this Project, our experience with similar projects, and our knowledge of sites with similar surface and subsurface conditions.

Floor Slab System (Flat Slab)

As noted previously, the subsurface soils exhibit a high potential to undergo expansion and contraction with fluctuations in their moisture contents. Based on our calculations, the subsoils at this site may yield a PVR ranging between 3½ to 4 inches. A “dock high” grade supported floor may be used at the site provided the pad is prepared in accordance with the recommendations in the Building Pad Preparation section of this report. The actual movement could be greater if inadequate drainage or other sources of water are allowed to infiltrate beneath or pond around the structure after construction.

Monolithic Slab Without Grade Beams. If the building subgrade and fill pad are prepared to be non-expansive in the Earthwork section of this Report, the floor slab may be designed in accordance with Chapter 18, Section 1808.6.3 of the 2015 IBC manual. Design parameters are provided below for the appropriate floor slab design method.

CRSI (Concrete Reinforcing Steel Institute) Method 1, 2, 3, 6

Net Allowable Bearing Pressures5 Total Load Conditions (psf): 3000

Dead Load Plus Gravity Live Load Conditions (psf): 2000 Maximum Allowable Deflection Ratio of Beam Footing: 1/360

Subgrade Modulus, k (pci): See table below

WRI (Wire Reinforcement Institute) Method 1, 2, 3, 6

Design Plasticity Index4: 23 Climatic Rating (Cw): 16

Soil Climate Support Index (1-C): 0.09 Site Slope (%): 0

Soil Unconfined Compressive Strength, qu (tsf): 1.0 Net Allowable Bearing Pressures5:

Total Load Conditions (psf): 3000 Dead Load Plus Gravity Live Load Conditions(psf): 2000

Maximum Allowable Deflection Ratio of Foundation Beam: 1/360

Floor Slab Design Notes. The following notes apply to the floor slab design methods presented above.

1 Design parameters are based on preparing the subgrade and constructing a building pad as recommended in the Earthwork section of this report.


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2 This is essentially an empirical design method and the recommended design parameters are based on our understanding of the proposed Project, our interpretation of the information and data collected as a part of this study, our area experience, and the criteria published in the WRI and CRSI design manuals.

3 If the floor slab of the foundation is to be covered with wood, vinyl tile, carpet, or other moisture sensitive or impervious coverings, a vapor barrier should be placed beneath concrete slab foundations or concrete floor slabs if they are bearing directly on the ground. The designer should be familiar with the American Concrete Institute (ACI) 302 for procedures and cautions about the use and placement of a vapor barrier.

4 Based on the weighted average method for a depth of 15 feet. 5 Includes a factor of safety (FS) of at least 2 for total load conditions and at least 3 for dead load plus gravity

live load conditions. 6 The estimated settlement beneath the foundation units, provided proper and quality construction is

performed, is less than 1 inch.

The perimeter grade beam may be supported by strip footings or drilled piers. Perimeter grade beams can be sized for a net allowable bearing pressure of 5,000 psf for dead load plus gravity live load conditions. The strip footings will be supported by a Vertical Moisture Barrier (VMB).

Forklift Traffic

Portions of the floor slab may be subject to forklift traffic. ACI 360 Design of Slabs on Grade discusses slab foundations and forklift type traffic in more detail. Modulus of subgrade reaction, k, values are provided below that can be used to design the floor slab with regard to forklift traffic and loads. The following k values may be used:

k-value

Select Fill Type Granular Select Fill Thickness 2 Existing

Subgrade Prepared Subgrade

Granular Select Fill Material 1

6 inches 75 pci 150 pci




1 Granular select fill shall meet one of the following criterion: • Crushed stone (limestone) meeting Type A, Grades 1, 2, or 3 of the 2004 TxDOT Standard

Specifications for Construction and Maintenance of Highways, Streets, and Bridges. Designation as a GC or GM in accordance with the Unified Soil Classification System (USCS).

• Crushed or uncrushed gravel meeting Type B, Grades 1, 2, or 3 of the 2004 TxDOT Standard Specifications for Construction and Maintenance of Highways, Streets, and Bridges. Designation as a GC or GM in accordance with the USCS.

• Crushed concrete meeting Type D, Grades 1, 2, or 3 of the 2004 TxDOT Standard Specifications for Construction and Maintenance of Highways, Streets, and Bridges. Designation as a GC or GM in accordance with the USCS.

Recommendations are provided in the Fill Materials and Placement section of this report. 2 Granular Select Fill Thickness is the depth immediately beneath the floor slab.

In addition to designing the floor slab for forklift loads and traffic volume, the floor slab design should also consider the abrasive impact that the vehicle has on the floor slab.


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Some techniques used to increase floor slab abrasion resistance include:

• Using a 28-day compressive strength that is at least 4,000 psi and the flexural strength is at least 650 psi.

• Using a low slump concrete mix that has a water-to-cement ratio not greater than 0.45.

• Using fiber mesh in the concrete mix.

• Using a more durable aggregate in the concrete mix design such as trap rock or river gravel rather than limestone aggregate.

• Applying a hardened surface treatment and finish.

Spread or Strip Footings

We understand that the interior columns for the building may be supported by isolated spread footings and the tilt-wall panel structures may be supported by perimeter strip footings. If the building pad is prepared based on the Earthwork section of this report, the interior columns can be supported on individual spread footings bearing or select fill and the tilt-wall panel structures can be supported by strip footings bearing on a VMB. A Drash representative should be on site to inspect subgrade when spread or strip footings are excavated. The perimeter strip footings should bear no shallower than 24 inches below final site grade. Interior spread footings shall bear at least 18 inches below the bottom of the slab.

In select fill, the spread footings may be designed for a total load net bearing pressure of 3,000 psf or a dead load plus gravity live load net bearing pressure of 2,000 psf, whichever results in a larger bearing surface. These bearing pressures include a factor of safety of approximately two (2) and three (3), respectively.

The perimeter strip footings will bear on a VMB and should be designed for a dead load net bearing pressure of 5,000 psf. This bearing pressure includes a factor of safety of approximately three (3).

We understand that the spread or strip footings may be subjected to lateral loading such as shear and moment loading. Hence, the footings shall be designed to accommodate that lateral loading and shall have adequate safety factors against overturning and sliding conditions.

The spread or strip footings can provide some uplift resistance for those structures subjected to wind or other induced structural loading. The uplift resistance of a spread or strip footing may be computed using the effective weight of the soil above the spread or strip footing along with the weight of the spread or strip footing and structure. A soil unit weight of 100 pcf may be assumed for the on-site soils placed above the spread or strip footing, provided the fill is properly compacted. The uplift resistance of a spread or strip footing may be computed using the weight of the spread or strip footing and structure.

These design soil criteria are for single, isolated spread or strip footings. Spread or strip footings on different levels should be placed such that a downward 1(V):2(H) projection from the leading edge of the upper foundation passes below the adjacent, deeper foundation unit. All spread or strip footings should be located such that their edge-to-edge spacing is at least 25


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percent of the width of the largest foundation involved. If closer foundation spacing is necessary, we should be contacted to evaluate if the individual spread or strip footing capacity is still valid or if a reduction in the individual foundation capacity is necessary due to the close foundation spacing. The final foundation layout should be reviewed by the Geotechnical Engineer.

Settlements should be less than one-half (½) inch for properly designed and installed foundations. Settlement of spread or strip footings will be more sensitive to installation techniques than to soil-structure interaction.

Construction Considerations Spread or strip footing foundations should preferably be neat excavated. Excavation should be accomplished with a smooth-mouthed bucket. If a toothed bucket is used, excavation with this bucket should be stopped six (6) inches above the final bearing surface and the excavation completed with a smooth-mouthed bucket or by hand labor. If neat excavation is not possible then the foundation should be overexcavated and formed. All loose materials should be removed from the overexcavated areas and filled with lean concrete or compacted cement stabilized sand (two sacks cement to one cubic yard of sand) or flowable fill. If the subsoils are sandy or gravelly in nature, they may not remain in a vertical cut for any significant timeframe. If this is the case, it will be necessary to use formwork to complete the grade beam construction.

Steel should be placed and the foundation poured the same day of excavation. If not, a seal slab consisting of lean concrete should be poured to protect the exposed foundation soils. The bearing surface should be excavated with a slight slope to create an internal sump for runoff water collection and removal. If surface runoff water in excess of one (1) inch accumulates at the bottom of the excavation, it should be pumped out prior to concrete placement. Under no circumstances should water be allowed to adversely affect the quality of the bearing surface.

If the spread or strip footing is buried, backfill above the foundation may be the excavated select fill soils. Backfill soils should be compacted to at least 95 percent of the maximum dry density as determined by the standard moisture/density test (ASTM D 698) at moisture contents ranging from minus two (-2) to plus three (+3) percentage points of the optimum moisture content. The backfill should be placed in thin, loose lifts not to exceed eight (8) inches, with compacted thickness not to exceed six (6) inches.

Drilled Piers

Design Considerations. Drilled piers may be used to support the columns and tilt-wall panels for the structures. Perimeter grade beams can be supported on drilled piers. Only straight-sided piers have been considered for this project. Recommendations for straight-sided piers are provided in the following sections. Piers should not terminate shallower than 10 feet or deeper than 35 feet without contacting our office.

If the tilt-wall panels are supported by grade beams spanning between drilled piers, the grade beams will need to be on 6-inch void boxes. If the tilt-wall panels are supported directly by the drilled piers, 6-inch void boxes should still be used under the panels between the piers. Place soil retainer block between the void box and grade beam backfill.


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Conventional tilt-wall construction usually results in the backfilling of a portion of the pour strip area between the floor slab and wall panel, after the wall panels have been erected. Compaction of the backfill on both sides of the panels should receive special attention. The backfill along the interior of the tilt-wall should consist of gravelly clay or silty clay select fill compacted to the moisture and density levels discussed later in this report. Highly permeable soils such as gravels, sands, and clayey sands should not be used as backfill. As an alternative to select material, the backfill may also consist of controlled low strength fill material. This material is typically referred to as “flowable fill” and is further defined in ACI 229R.

Compressive axial loads on pier foundations are resisted by both side friction along the shaft and by end bearing at the base of the shaft. Uplift loads are resisted solely by side friction along the drilled pier shaft, the weight of the drilled pier, and the structure dead load acting on the drilled pier.

Piers shall be designed based on the following table:

COMPRESSION LOADING – STRAIGHT-SIDED PIERS

Elevation, ft.

Allowable Side Friction (SF=2), psf

Allowable End Bearing, psf Total Load

(Safety Factor (SF) = 2) Dead Load + Gravity Live Load

(SF = 3) 0 - 4 --- --- ---

4 – 10 470 --- --- 10 - 15 850 17,000 11,000 15 - 35 1350 27,000 18,000

For straight-sided piers, the side shear should be neglected for the initial 4 feet as measured below the existing ground and within one (1) pier diameter of the bottom of the shaft.

For adjacent straight-sided piers, we recommend a minimum edge-to-edge spacing of at least two (2) pier diameters based on the larger diameter of the two adjacent piers. In locations where this minimum spacing criterion cannot be accomplished, Drash should be contacted to evaluate the locations on a case-by-case basis.

In addition to the axial compressive loads on the piers, these piers will also be subjected to axial tension loads due to swelling of the near surface clay soils and possibly due to other induced structural loading conditions. To compute the axial tension force due to the swelling soils along straight-sided piers, the following equation may be used.

Qu = 51 ● d

Where: Qu = Uplift force due to expansive soil conditions in kips (k) d = Diameter of pier in feet (ft)

This calculated force can be used to compute the longitudinal reinforcing steel required in the pier to resist the uplift force induced by the swelling clays. However, the cross-sectional area of the reinforcing steel should not be less than ½ percent of the gross cross-sectional area of the


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drilled pier. The reinforcing steel should extend from the top to the bottom of the pier to resist this potential uplift force.

The ultimate uplift resistance of straight-sided drilled piers can be evaluated using the following equation:

Qr = 3.4 ● d ● Dp + Wp + PDL

Where: Qr = Ultimate uplift resistance of pier in kips (k) d = Diameter of pier in feet (ft) Dp = Founding depth of pier in natural soils minus the upper 15

feet of pier in contact with the soil in feet (ft) Wp = Weight of the drilled pier in kips (k) PDL = Dead Load acting on the drilled pier in kips (k)

For straight-sided piers, we recommend that a factor of safety of at least two (2) be applied to the computed ultimate uplift resistance.

For piers, total settlements, based on the indicated bearing pressures, should be about 1 inch or less for properly designed and constructed drilled piers. Settlement beneath individual piers will be primarily elastic with most of the settlement occurring during construction. Differential settlement may also occur between adjacent piers. The amount of differential settlement could approach 50 to 75 percent of the total pier settlement. For properly designed and constructed piers, differential settlement between adjacent piers is estimated to be less than ¾ of an inch. Settlement response of drilled piers is impacted more by the quality of construction than by soil-structure interaction.

Improper pier installation could result in differential settlements significantly greater than we have estimated. In addition, larger magnitudes of settlement should be expected if the soil is subjected to bearing pressures higher than the allowable values presented in this report.

The drilled pier should be steel reinforced to resist the axial forces that it will be subjected. However, the quantity of steel should not be less than ¾ percent of the gross cross-sectional area of the drilled pier shaft for foundations controlled by axial load conditions. The reinforcing steel should extend from the top to the bottom of the drilled pier shaft. A minimum of three inches of concrete cover should be provided between the soil and outer edge of the steel reinforcement.

Construction Considerations. The pier foundation excavations should be augered and constructed in a continuous manner. Steel and concrete should be placed in the excavations immediately following drilling and evaluation for proper bearing stratum, embedment, and cleanliness. Under no circumstances should the excavations remain open overnight.

We do not anticipate sloughing issues; however, the contractor should be prepared to use casing to control sloughing of the pier excavation sidewalls. Please note that this commentary on casing does not mean that it will occur. The point being made is that the contractor needs to have casing available and should include a unit price option in his/her bid. The casing method is discussed in the following paragraphs.


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Casing Method - If subsurface water or sloughing of the subsurface materials are encountered during pier excavation, casing may be required. Casing will provide stability of the excavation walls and will reduce water influx; however, casing may not completely eliminate subsurface water influx potential. In order for the casing to be effective, a “water tight” seal must be achieved between the casing and surrounding soils. The drilling subcontractor should determine casing depths and casing procedures. Water that accumulates in excess of six (6) inches in the bottom of the pier excavation should be pumped out prior to steel and concrete placement. If the water is not pumped out, a closed-end tremie should be used to place the concrete completely to the bottom of the pier excavation in a controlled manner to effectively displace the water during concrete placement. If water is not a factor, concrete should be placed with a short tremie so the concrete is directed to the bottom of the pier excavation. The concrete should not be allowed to ricochet off the walls of the pier excavation nor off the reinforcing steel.

If this operation is not successful or to the satisfaction of the foundation contractor, the pier excavation should be flooded with fresh water to offset the differential water pressure caused by the unbalanced water levels inside and outside of the casing. When the pier excavation depth is achieved and the bearing area has been cleaned, steel and concrete should then be placed immediately in the excavation. The concrete should be tremied completely to the bottom of the excavation with a closed-end tremie.

Removal of casing should be performed with extreme care and under proper supervision to minimize mixing of the surrounding soil and water with the fresh concrete. Rapid withdrawal of casing or the auger may develop suction that could cause the soil to intrude into the excavation. An insufficient head of concrete in the casing during its withdrawal could also allow the soils to intrude into the wet concrete. Both of these conditions may induce "necking", a section of reduced diameter, in the pier.

All aspects of concrete design and placement should comply with the most recent version of American Concrete Institute (ACI) 318 Building Code Requirements for Structural Concrete, ACI 336.1, the section titled Standard Specification for the Construction of Drilled Piers, ACI 336.3, the section titled Suggested Design and Construction Procedures for Pier Foundations. Concrete should not be placed, if the temperature is 40oF and dropping or if it is not expected to be above 40oF for the initial 72 hours without concrete blankets and heaters. All other weather related concrete requirements in ACI 318 Sections 5.12 (cold) and 5.13 (hot), ACI 305.1 and ACI 306.1 will apply. Concrete should be designed to achieve the specified 28-day strength when placed at an 8-inch slump with a ±1-inch tolerance. Adding water to a mix that has been designed for a lower slump does not meet the intent of this recommendation. If a high range water reducer is used to achieve this slump, the span of slump retention for the specific admixture under consideration should be thoroughly investigated. Compatibility with other


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concrete admixtures should also be considered. A technical representative of the admixture supplier should be consulted on these matters.

Successful installation of drilled piers is a coordinated effort involving the general contractor, design consultants, subcontractors and suppliers. Each must be properly equipped and prepared to provide their services in a timely fashion. Several key items are:

• Proper drilling rig with proper equipment (including casing, augers, and teeth);

• Reinforcing steel cages tied to meet project specifications;

• Proper scheduling and ordering of concrete for the piers; and

• Monitoring of the installation by design professionals.

Foundation construction should be carefully monitored to assure compliance of construction activities with the appropriate specifications. Particular attention to the referenced publication is warranted for foundation installation. A number of items for foundation installation include those listed below.

• Foundation locations • Concrete properties and placement

• Vertical alignment • Proper casing seal for subsurface water control

• Competent bearing • Casing removal

• Steel placement

Seismic Design Considerations

Presented below are the seismic design criteria for the Project site and immediate area.

Description Value 2015 International Building Code Site Classification (IBC) 1 D2

Site Latitude 29.61440°

Site Longitude -98.28128°

Maximum Considered Earthquake 0.2 second Design Spectral Response Acceleration (SDS) 0.081

Maximum Considered Earthquake 1.0 second Design Spectral Response Acceleration (SD1) 0.049 1 As per the requirements of Section 1613.3.2 in the 2015 IBC, the site class definition was determined

using Table 20.3-1 of Chapter 20 of American Society of Civil Engineers (ASCE) 7. The Spectral Acceleration values were determined using publicly available information provided on the United States Geological Survey (USGS) website.

2 Note: Chapter 20 of ASCE 7 requires a site soil profile determination extending to a depth of 100 feet for seismic site classification. The current scope does not include the required 100-foot soil profile determination. The borings extended to a maximum depth of 35 feet, and this seismic site class definition considers that hard soil continues below the maximum depth of the subsurface exploration. Additional exploration to deeper depths would be required to confirm the conditions below the current depth of exploration.


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Corrosion Considerations

Laboratory testing was conducted on a soil sample recovered from one of the borings to assess the corrosivity risk of the soils at the site. The soil sample was submitted to an analytical lab to determine the sulfate content. The result of the laboratory test is provided below.

Summary of Laboratory Sulfate Test

Boring No. Sample Depth (ft) Sulfate (ppm)

B-1 2 – 4 409

According to the 2015 IBC, concrete that will be exposed to sulfate-containing solutions should be designed in accordance with ACI 318. The sulfate test result indicates that the sulfate exposure levels are low. Therefore, Type I or Type II cement may be used at this site.

Landscape Design

We realize that landscaping is vital to the aesthetics of any project. The Project Owner and Project Design Team, particularly the Architect and Landscape Architect, should be made aware that placing large bushes and trees adjacent to the structures may contribute to future distress to the foundation system and structure. Vegetation placed in landscape beds that are adjacent to the structure should be limited to small plants and shrubs that will not exceed a mature height of about four (4) feet and that are not ‘water demanding’.

Large bushes and trees that will generally exceed 4-foot heights should be planted at a distance away from the structure so that their canopy or ‘drip line’ does not extend to the structure’s perimeter when the tree reaches maturity. Plants and shrubs that are ‘water hungry’ should not be planted within five (5) feet of the structure. Watering of vegetation, particularly landscape beds adjacent to the structure, should be performed in a timely and controlled manner. Excessive watering, as well as, inconsistent watering, should be avoided.

Drainage Adjacent to Structures

The performance of the foundation system for the proposed structures will not only be dependent upon the quality of construction, but also upon the stability of the moisture content of the soils underlying the foundation. The Project Civil Engineer should design final site grades so that there is positive surface drainage away from the structures. Post-construction accumulation or ponding of surface runoff near structures must be avoided.

Utility Trenches

Various utilities will be installed at the Site. The utilities may include sanitary sewer lines, storm drainage (i.e., sewer lines, concrete drainage channels, culverts, etc.), electrical lines, gas lines, and telecommunication lines. Installation of these utilities should conform to the applicable specifications of the utility entities as follows:

• Sanitary Sewer and Water Lines

o San Antonio Water System (“SAWS”) 2008 Specifications for Water and Sanitary Sewer Construction; latest revision.


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o City of San Antonio (“COSA”) Grading and Clearing Ordinance 94002; as amended.

• Storm Water Sewer Lines and Storm Drainage

o COSA 2008 Standard Specifications for Construction; latest revision.

o COSA Grading and Clearing Ordinance 94002; as amended.

• Electrical and Gas Lines

o City Public Service (“CPS Energy”) Electrical Service Standards; latest edition.

o CPS Energy Gas Service Standards; latest edition.

o COSA Grading and Clearing Ordinance 94002; as amended.

Utilities not referenced above, such as telecommunications, small water lines, or sanitary sewer laterals, should meet the following minimum installation guidelines.

• The bottom of the utility trench excavation should be clean of loose soils and debris prior to placement of the utility pipe or cable.

• Backfill above the utility pipe or cable should be as follows:

o Traversing Non-Pavement or Non-Load Bearing Areas

The backfill soils may be the excavated soils.

Place the backfill soils in loose lifts not to exceed 8 inches in thickness to achieve compaction thickness no greater than 6 inches.

Add water as applicable so that the soil moisture content after compaction is between minus 2 and plus 3 percent of the optimum moisture content.

Compact the backfill soil lift to at least 95 percent of standard moisture-density relationship (ASTM D 698).

o Traversing Pavement or Load Bearing Areas

• Place 12 inches of backfill soils, which may be the excavated soils, above the utility pipe or cable. The backfill soils should be:

o Place the backfill soils in loose lifts not to exceed 8 inches in thickness to achieve compaction thickness no greater than 6 inches.

o Add water as applicable so that the soil moisture content after compaction is between minus 2 and plus 3 percent of the optimum moisture content.

o Compact the backfill soil lift to at least 95 percent of standard moisture-density relationship (ASTM D 698).

Place flowable fill in the utility trench, terminating at a depth to accommodate the applicable pavement section or slab.


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The flowable fill should have a 28-day compressive strength between 25 and 100 psi.

Utility trenches that traverse beneath the structure or through the foundation member are potential avenues for subsurface water to migrate beneath the structure. One of the following design recommendations should be considered by the Project Civil or MEP Engineers:

• If the utility trench traverses beneath the structure, a ‘clay soil plug’ should be used for the bedding and backfill. The clay soil plug should have a plasticity index (PI) between 18 and 25. The clay soil plug should be at least 5 feet in length, extend equally across the structure perimeter, and extend full depth of the trench. Granular materials, unless specifically required by the utility company or local codes, should not be used for bedding or backfill along the clay soil plug. If granular bedding or backfill is to be used, we must be contacted to address this issue. Backfill material placement should follow the recommendations in the Fill Materials and Placement section of this Report.

• If the utility pipes/cables traverse through the foundation member, the hole should be filled with flowable fill or concrete. The pipes/cables traversing through this zone should be designed with some flexibility if they are sensitive to movement. In lieu of this approach, a ‘pipe sleeve’ can be installed through the foundation member for the utility lines to pass through. The pipe sleeve should have a clearance that is at least 6 inches larger than the outer edges of the utility pipes/cables. The annulus within the pipe sleeve should be filled with a flexible but water-proof material such as sealants or asphaltic mastics.

Earthwork

Recommendations and guidelines for general site preparation, building pad preparation, and placement of fill soils at the Project site are discussed in this section. The recommendations presented for design and construction of earth supported elements including foundations and floor slabs are contingent upon following the recommendations and guidelines outlined in this section. Earthwork on the Project should be evaluated by our firm. The evaluation of earthwork should include observation and testing of all fill soils placed at the site, subgrade preparation beneath buildings and pavements, and any load-bearing requirements within the Project.

The contractor or its applicable subcontractor(s) are responsible for designing and constructing stable, temporary excavations, as required to maintain stability of both the excavation sides and bottom. Excavations should be sloped or shored in the interest of safety following local and federal regulations, including current OSHA excavation and trench safety standards.

General Site Preparation Construction operations may encounter difficulties if the surface soils become wet or soft due to the weather, becoming a general hindrance to equipment from rutting and pumping of the soil surface, especially during and soon after periods of wet weather. If the subgrade cannot be adequately compacted to the minimum densities as described in the Fill Materials and Placement section of this report, one of the following measures may be required:

• Removal and replacement with select fill;


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• Chemical treatment of the soil to dry and increase the stability of the subgrade; or

• Drying by natural means if the schedule allows.

Drash should be contacted for additional recommendations, if soil support during construction is needed.

Prior to placing any fill, all vegetation, loose topsoil and any otherwise unsuitable materials should be removed from the construction area. The stripped materials consisting of vegetation and organic materials should be wasted from the site, or used to re-vegetate landscaped areas or exposed slopes after completion of grading operations. Wet or dry material should either be removed or moisture conditioned and re-compacted.

Building Pad Preparation

Proposed grades and the FFE were not available to us at the time this report was prepared. For our recommendations, we have assumed that the FFE will be near the existing grades. Once the FFE become available, Drash should be contacted to re-evaluate our recommendations.

The subsurface soils at this site generally exhibit a high potential to undergo expansion and contraction during fluctuations in their moisture contents. Based on the information developed from our field and laboratory programs, we calculate that the subgrade soils at this site may yield a Potential Vertical Rise (PVR) ranging between 3½ and 4 inches. However, the actual PVR could be greater than calculated if inadequate drainage or other sources of water are allowed to infiltrate beneath or pond around the structures during and after construction.

Excavation & Replacement with Select Fill

• Strip vegetation, loose topsoil and any otherwise unsuitable materials from the building area. The building area is defined as the area that extends at least 3 feet (horizontal) beyond the perimeter of the proposed building and any adjacent flatwork. The stripped materials consisting of vegetation and organic materials should be wasted from the site, or used to re-vegetate landscaped areas or exposed slopes after completion of grading operations. Wet or dry material should either be removed or moisture conditioned and re-compacted.

• After stripping, excavate the upper 8 feet from the building area and either use it in landscape areas or remove it from the site.

• Before placing any fill, the exposed subgrade in the building area should be proofrolled with at least a 20-ton roller, or equivalent equipment, to evidence any weak yielding zones. A technical representative of our firm should be present to observe proofrolling operations. If any weak yielding zones are present, they should be over excavated, both vertically and horizontally, to expose competent soil. The excavated soil can be used to restore grade provided that the material is relatively free and clean of deleterious material or materials exceeding 3 inches in maximum dimension.

• After proofrolling and replacing any weak yielding zones, scarify the exposed subgrade to 6 inches, moisture condition the soils and compact to at least 95


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percent of the maximum dry density determined in accordance with the Standard effort (ASTM D 698). The exposed subgrade should be moisture conditioned between +2 and +4 percentage points of the optimum moisture content.

• Select fill should then be placed to achieve an elevation 6 inches below the finished building pad elevation (FBPE). Recommendations for select fill are included in the Fill Materials and Placement section of this report.

• To provide uniform slab support and create a more all-weather working surface, we recommend constructing the final 6 inches of the building pad with granular select fill. The granular select fill should be moisture conditioned between -2 and +3 percentage points of the optimum moisture content, and then compacted to at least 95 percent of the maximum dry density determined in accordance with ASTM D 698. Recommendations for granular select fill are included in the Fill Materials and Placement section of this report.

• A clay cap should be installed on the east side of the building as described in the Clay Cap section of this report.

Vertical Moisture Barrier (VMB)

The purpose of the VMB is to help prevent water from flowing into the building pad and to help maintain moisture contents in the soils below the building at a constant level. Pertinent details for the VMB are presented below:

• The depth of the VMB should be 6.5 feet below the bottom of the perimeter beam or at least 6 inches below the select fill whichever is deeper (See Exhibit 3).

• The width of the VMB should be at least as wide as the proposed perimeter strip footing, but not less than 12 inches. The width of the VMB can be greater than the perimeter foundation beam but should not be less than the width of the foundation beam as determined by the structural engineer.

• The VMB should completely surround the building.

• The VMB should be installed upon completion of the building pad.

• The VMB trench excavation should only extend as far as it can be installed each day to prevent sloughing of the trench sidewalls.

• Excavation should be accomplished with a smooth-mouthed bucket. If a toothed bucket is used, excavation with this bucket should be stopped 6 inches above final grade and the excavation should be completed with a smooth-mouthed bucket.

• The bottom of the VMB excavation should be free of debris and loose or soft soil prior to placing the moisture retarder and cementitious backfill. Loose, soft material in the bottom of the trench may result in settlement of the beam.

• When the daily trench excavation is completed, drape a 10-mil thick PVC moisture retarding sheet along the inside trench wall such that it extends from the bottom to the top of the trench wall and beneath the floor slab.


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• The PVC moisture retarder (10-mil) should meet the requirements of ASTM E 1745. HDPE may also be considered instead of PVC provided it meets these requirements.

• After placing the PVC sheeting in the trench, fill the trench with flowable fill as defined in the 2014 TxDOT Item 401 but having a minimum strength of 100 psi at 28-days. As an alternative, a high slump (6 to 8 inches), lean, two-sack concrete mixture may be used. The VMB excavation should be backfilled the same day that excavation is performed to reduce the potential for sloughing of the VMB excavation sidewalls. The excavated length/runs of the VMB installed at one time may need to be shortened to reduce sloughing of the VMB excavation sidewalls. Furthermore, temporary shoring of the VMB excavation may be considered to reduce sloughing.

• Repair VMB from any utility trenches that breach the barrier. Utility trenches that breach the VMB can be repaired with the use of flowable fill to re-establish the former wall section. Alternatives for repairing the barrier from utility trenches can best be determined during construction.

• The successful performance of the foundation system is critical to proper preparation of the VMB and building pad. Thus, the compacted moisture and density levels are critical. The fill soils must be protected from drying out during and after compaction operations and during installation of the VMB.

Bathtub Condition

Excavation and replacement of expansive soils with granular fill may cause water to collect within the granular material as water is often confined by the less permeable expansive soils found at the bottom and walls of the excavation. The result of this collected water is commonly referred to as a ‘bathtub’ condition. This collected water can cause the expansion or softening of the clay subgrade soils, which often results in foundation distress. Use of cohesive soil in lieu of granular fill can reduce the potential for a bathtub condition. Two methods to reduce the potential for a bathtub condition are as follows:

Method 1 (Lean Clay Select Fill)

• Use Lean Clay (CL) as select fill material within the building pad, except for the final 6 inches which can be a granular fill material. The Lean Clay material should have at least 70 percent of the total material passing the No. 200 sieve, a Liquid Limit (LL) no greater than 40, a Plasticity Index (PI) between 7 and 20, and no more than 15 percent by weight retained on the No. 4 Sieve.

Method 2 (Granular Select Fill)

• Slope the clay subgrade within the building area to allow for collection of water.

• Lime treat the top 6 inches of the sloping subgrade.

• Collect the water in an interceptor drain or a French drain and dispose of the water in a sump or other drainage network as appropriate. The design of this


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type of system is beyond our scope of services; however, we can address this issue in more detail at your request.

Clay Cap

If not covered with concrete flatwork or pavements, the final 2 feet of the 3-foot (horizontal) building pad overbuild should consist of a cohesive clay with a plasticity index (PI) between 18 and 25 percent. The 2-foot ‘clay cap’ should have at least 70 percent by weight passing the No. 200 Sieve and no more than 15 percent by weight retained on the No. 4 Sieve. The clay cap should extend at least 2 feet beyond the perimeter of the building pad overbuild. The clay cap may be replaced with concrete flatwork or pavement extending to the edge of the foundation. Properly compacted, this clay cap should help to reduce migration of moisture into the select fill below. The clay cap should be placed and compacted as noted in the following section.

Fill Materials and Placement

Unless noted otherwise in another section of this report, select fill should meet the following criteria.

Specifications for Fill Materials

Fill Type 1 Acceptable Location for Placement

Granular 2

Select Fill Above the existing grade or as specified

Select Fill 3 All locations On-Site Soils

CH • The on-site CH (FAT CLAY) material does not meet select fill specifications. Unless noted

otherwise in this Report, on-site CH material can only be used for grade adjustments within general, non-structural and common areas. Otherwise, it should be removed from the site.

1 Fill, whether select or non-select, that is being placed in a controlled and compacted manner shall meet one of the above specifications, be free of debris (i.e. trash, rubble, organic materials, vegetation, roots), have no particles exceeding 3 inches in maximum dimension.

Prior to any filling operations, samples of the fill materials, whether select or non-select, to be used for construction shall be submitted for approval, which will include performing laboratory tests to verify compliance to the above specifications.

2 Granular Select Fill shall meet one of the following criterion: • Crushed stone (limestone) meeting Type A, Grades 1, 2, or 3 of the 2014 TxDOT Standard

Specifications for Construction and Maintenance of Highways, Streets, and Bridges. Designation as a GC or GM in accordance with the Unified Soil Classification System (USCS).

• Crushed or uncrushed gravel meeting Type B, Grades 1, 2, or 3 of the 2014 TxDOT Standard Specifications for Construction and Maintenance of Highways, Streets, and Bridges. Designation as a GC or GM in accordance with the USCS.

• Crushed concrete meeting Type D, Grades 1, 2, or 3 of the 2014 TxDOT Standard Specifications for Construction and Maintenance of Highways, Streets, and Bridges. Designation as a GC or GM in accordance with the USCS.

• Clayey gravel (may locally be referred to as “pit-run” material) or caliche having no particle sizes greater than 3 inches in any dimension, at least 50 percent of total material retained on the No. 200 sieve, a Liquid Limit (LL) no greater than 40, and a Plasticity Index (PI) between 7 and 20. Designation as a GC in accordance with the USCS.


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• Commercial Grade Base (may locally be referred to as “three-quarters to dust” material) that is produced by some local/regional quarries having nothing retained on the 2-inch sieve, at least 60 percent retained on the No. 40 sieve, at least 80 percent retained on the No. 200 sieve, a LL no greater than 30, and a PI of 7 or less. Designation as a GM in accordance with the USCS.

• Clayey sand or silty clayey sand (may locally be referred to as “pit-run” material) having no particle sizes greater than 3 inches in any dimension, at least 50 percent of total material retained on the No. 200 sieve, a LL no greater than 40, and a PI between 7 and 20. Designation as an SC in accordance with the USCS.

3 Select Fill shall meet the following criteria: • Lean clay having no more than 30 percent of total material retained on the No. 200 sieve, a LL no

greater than 40, and a PI between 10 and 20 and no more than 15 percent by weight retained on the No. 4 sieve. Designation as a CL in accordance with USCS.

Placement and Compaction Requirements for Fill Materials

Item Description

Fill and Backfill Lift Thickness All fill and backfill, select and non-select, should be placed in thin, loose lifts not to exceed 8 inches, with compacted thickness of about 6 inches.

Moisture Content and Compaction of Select Fill and Select Backfill

At least 95 percent of the maximum dry density as determined by the Standard effort (ASTM D 698); the materials should be moisture conditioned between -2 and +3 percentage points of the optimum moisture content.

Moisture Content and Compaction of On-Site Soils

At least 95 percent of the maximum dry density as determined by the Standard effort (ASTM D 698). The CH material shall be moisture conditioned between optimum and +4 percentage points of the optimum moisture content.

Clay Caps and Plugs

At least 95 percent of the maximum dry density as determined by the Standard effort (ASTM D 698). The soil shall be moisture conditioned to at least 2 percentage points above the optimum moisture content.

Pavements

Flexible pavement system may be considered for the Project. Based on our knowledge of the Project, we anticipate that traffic loads will be produced primarily by automobile traffic, delivery trucks, trash removal trucks and semi-tractor trailers. The pavement section on the north side of the building will be exclusively semi-tractor trailers.

Pavement Sections. The flexible pavement section was designed in general accordance with the National Asphalt Pavement Association (NAPA) Information Series (IS-109) method (Class 1 for Light and Class 2 for Heavy).

For this Project, Light, Heavy and Truck Dock and Truck Entrance pavement section alternatives are being provided. Light is for areas expected to receive only vehicle traffic such as cars, pick-ups, and SUV’s. Heavy assumes areas with heavy traffic, such as delivery lanes, and trash pickup areas. Truck Dock and Truck Entrance assumes areas with trucks turning, stopping and slow moving into the docking area. Please note that light pavement sections assume that no heavy traffic, such as busses, garbage trucks, delivery trucks, dump trucks, semi-tractor trailers, etc., will ever travel on the section. In addition, the


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anticipated traffic assumes that no construction equipment will ever travel on the sections. If heavier traffic loading is expected, Drash should be provided with the information and allowed to review these pavement sections.

FLEXIBLE PAVEMENT SYSTEM

Light Heavy

Truck Dock and

Truck Entrance

Hot Mix Asphaltic Concrete, (Type D) 2.0 inches 2.0 inches 3 inches 3 inches 2.0 Inches

Hot Mix Asphaltic Concrete, (Type C) ---- ---- ---- 3.5 inches

Granular Base Material 1 10.0 inches 6.0 inches 14.0 inches 10.0 inches 9.0 inches

Geogrid (TX – 5) No No No ---- Yes

Lime Treated Subgrade ---- 6.0 inches ---- 6.0 inches

Moisture Conditioned Subgrade 6.0 inches ---- 6.0 inches ---- 6.0 inches

1 Asphaltic base material may be used in place of granular base material. Every 2 inches of granular base material may be replaced with 1 inch of asphaltic base material. However, the minimum thickness of the asphaltic base material shall not be less than 4 inches.

RIGID PAVEMENT SYSTEM Compacted Soil Subgrade

Ramp Reinforced Concrete 9.0 inches 8.0 inches

Moisture Conditioned Raw Subgrade 6.0 inches ----

Lime Treated Subgrade ---- 6.0 inches

Concrete Section for ramp area shall meet the following requirements:

• No. 4 steel reinforcement bars at 12 inches on center each way.

• Mat steel continuous through construction joints; center mat steel in center of concrete section.

• No. 6 steel reinforcement dowels, 18 inches long and centered across joint, one end sleeved/greased, spaced at 24 inches on center.

• Rock or compacted fill subgrade.

A crack sealant compatible to both asphalt and concrete should be provided at all concrete-asphalt interfaces (i.e. curb to pavements).

The pavement subgrade is expected to consist of clayey soil or compacted select fill soils. Proper perimeter drainage is very important and should be provided so infiltration of surface water from unpaved areas surrounding the pavement is minimized. We do not recommend installation of landscape beds or islands in the pavement areas. Such features provide an avenue for water to enter into the pavement section and underlying soil subgrade. Water


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penetration usually results in degradation of the pavement section with time as vehicular traffic traverses the affected areas. Above grade planter boxes, with drainage discharge onto the top of the pavement or directed into sewers, should be considered if landscape features are desired. Also, the Asphalt Institute recommends a minimum of 2 percent slope for asphalt pavements. The importance of proper drainage cannot be overemphasized and should be thoroughly considered by the Project Team.

If curbs are proposed, the curbs should extend through the base and at least 3 inches into the soil subgrade below the base course. This will help reduce migration of subsurface water into the pavement base course from adjacent areas. A crack sealant compatible to both asphalt and concrete should be provided at all concrete-asphalt interfaces.

Pavement areas that will be subjected to heavy wheel and traffic volumes, such as waste bin or "dumpster" areas, entrance/exit ramps, and delivery areas, should be a rigid pavement section constructed of reinforced concrete. The concrete pavement areas should be large enough to properly accommodate the vehicular traffic and loads. For example:

• The dumpster pad should be large enough so that the wheels of the collection truck are entirely supported on the concrete pavement during lifting of the waste bin; and

• The concrete pavement should extend beyond any areas that require extensive turning, stopping, and maneuvering.

The pavement design engineer should consider these and other similar situations when planning and designing pavement areas. Waste bin and other areas that are not designed to accommodate these situations often result in localized pavement failures.

Pavement Section Materials Presented below are selection and preparation guidelines for various materials that may be used to construct the pavement sections. Submittals should be made for each pavement material. The submittals should be reviewed by Drash and any appropriate members of the Project Team. The submittals should provide test information necessary to verify full compliance with the recommended or specified material properties.

Hot Mix Asphaltic Concrete Surface Course - The asphaltic concrete surface course should be plant mixed, hot laid Type C or D Surface meeting the master specifications requirements of 2014 TXDOT Standard Specifications Item 341 and specific criteria for the job mix formula. The mix should be compacted between 91 and 95 percent of the maximum theoretical density as measured by TEX-227-F. The asphalt cement content by percent of total mixture weight should fall within a tolerance of ±0.3 percent asphalt cement from the specific mix. In addition, the mix should be designed so 75 to 85 percent of the voids in the mineral aggregate (VMA) are filled with asphalt cement. The grade of the asphalt cement should be PG 70-22 or higher performance grade. Aggregates known to be prone to stripping should not be used in the hot mix. If such aggregates are used measures should be taken to mitigate this concern. The


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mix should have at least 70 percent strength retention when tested in accordance with TEX-531-C.

Pavement specimens, which shall be either cores or sections of asphaltic pavement, will be tested according to Test Method TEX-207-F. The nuclear-density gauge or other methods which correlate satisfactorily with results obtained from Project pavement specimens may be used when approved by the Engineer.

Asphaltic Base Course - The asphaltic base material should meet the specification requirements of 2014 TxDOT Standard Specification Item 340, Type A or B.

Prime Coat - The prime coat should consist of sealing the base with an oil such as an MC-30 or an emulsion. The prime coat should be applied at a rate of about 0.2 to 0.5 gallons per square yard with materials which meet TxDOT Item 300. The prime coat will help to minimize penetration of rainfall and other moisture that penetrates the base.

Granular Base Material - Base material may be composed of crushed limestone base meeting all of the requirements of 2014 TxDOT Item 247, Type A, Grade 1 or 2; the material should have no more than 15 percent of the material passing the No. 200 sieve.

The base should be compacted to at least 98 percent of the maximum dry density determined in accordance with the Standard effort (ASTM D 698) at moisture contents ranging between -2 and +3 percentage points of the optimum moisture content.

Concrete - Concrete should have a minimum 28-day design compressive strength of 4,000 psi and a design flexural strength of 650 psi.

Moisture Conditioned Subgrade - The subgrade should be scarified to a depth of 6 inches and then moisture conditioned and compacted as recommended in this Report.

Lime Treated Subgrade - The subgrade shall be treated with hydrated lime in accordance with TxDOT Item 260 in order to improve its strength and improve its load carrying capacity. The quantity of hydrated lime required should be determined after the Site is stripped of the loose topsoil and the subgrade soils are exposed. In addition, the soils should be checked for sulfates prior to the use of lime. We anticipate that approximately 4 to 6 percent hydrated lime will be required. This is equivalent to about 18 to 27 pounds of hydrated lime per square yard for a 6-inch treatment depth. However, the actual percentage should be determined by laboratory tests on samples of the subgrade materials prior to construction. The optimum hydrated lime content should result in a soil-cement mixture with a pH of at least 12.4 when tested in accordance with ASTM C 977, Appendix XI.


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The hydrated lime should initially be blended with a mixing device such as a pulvermixer. After sufficient moisture conditioning, the treated soil mixture shall be compacted to at least 95 percent of the maximum dry density as determined in accordance with the Standard effort (TEX-114-E) at moisture contents from optimum to +3 percentage points of the optimum moisture content. If the in-place gradation requirements can be achieved during initial mixing, the remixing after the curing period can be eliminated.

Pavement Joints, Reinforcement, and Dowels

The following is recommended for all concrete pavement sections in this report. Refer to ACI 330 “Guide for Design and Construction of Concrete Parking Lots” for additional information.

Contraction Joint Spacing: 10 feet each way.

Contraction Joint Depth: At least ¼ of pavement thickness.

Contraction Joint Width: Shall be ¼ inch or as required by joint sealant manufacturer.

Construction Joint Spacing: To attempt to limit the quantity of joints in the pavement, consideration can be given to installing construction joints at contraction joint locations, where it is applicable.

Construction Joint Depth/Width:

Full depth of pavement thickness. Construction sealant reservoir along one edge of the joint. Width of reservoir to be ¼ inch or as require by joint sealant manufacturer. Depth of reservoir to be at least ¼ of pavement thickness.

Isolation Joint Spacing: As required to isolate pavement from structures, etc.

Isolation Joint Depth: Full depth of pavement thickness.

Isolation Joint Width: Shall be ½ to 1 inch or as required by the joint sealant manufacturer.

Expansion Joint:

None (Please note that in this general area, drying shrinkage of the concrete typically significantly exceeds anticipated expansion due to thermal affects. As a result, the need for expansion joints is eliminated provided all joints (including saw cuts) are sealed. Construction of an unnecessary joint may also become a maintenance problem. All joints should be sealed. If all joints, including sawcuts, are not sealed then expansion joints should be installed.

Distributed Steel:

Steel reinforcement may consist of steel bars described as follows: • No. 3 reinforcing steel bars at 12 inches on-center-each-way,

Grade 60; or • No. 4 reinforcing steel bars at 18 inches on-center-each-way

Grade 60.

All construction joints shall have dowels. Dowel information varies with pavement thickness as follows:

Pavement Thickness: 8 inches 9 inches Dowels: 1 inch diameter 11/8 inch diameter Dowel Spacing: 12 inches on center 12 inches on center Dowel Length: 16 inches long 16 inches long Dowel Embedment: 8 inches 7 inches


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Curbs shall be dowelled to the concrete pavement section.

INTERPRETATION OF REPORT

Drash understands that its geotechnical engineering report is used by the Client and various individuals and firms involved with the design and construction of the Project. Drash should be invited to attend Project meetings (in person or teleconferencing) or be contacted in writing to address applicable issues relating to the geotechnical engineering aspects of the Project. Drash should also be retained to review the final construction plans and specifications to evaluate if the information and recommendations in our geotechnical engineering report has been properly interpreted and implemented in the design and specifications.

CONSTRUCTION MONITORING AND TESTING

The performance of the foundation system for the proposed structure will be highly dependent upon the quality of construction. As the Geotechnical Engineer of Record for this Project, Drash should be retained to provide construction observation and materials testing services during the Project, particularly the construction activities relating to foundations, building pad, pavements, excavation and site grading.

LIMITATIONS OF REPORT

This geotechnical engineering report is based upon the information provided to us by the Client and various other individuals and entities associated with the Project, exploratory borings drilled within the Project limits, laboratory testing of randomly selected soil or rock samples recovered during drilling of the exploratory borings, and our engineering analyses and evaluation. The Client and readers of this geotechnical engineering report, should realize that subsurface variations and anomalies can and will exist across the site and between the exploratory borings. The Client and readers should realize that site conditions will change due to the modifying effects of seasonal and climatic conditions.

The nature and extent of such site or subsurface variations may not become evident until construction commences or is in progress. If site and subsurface anomalies or variations exist or develop, Drash should be contacted immediately so that the situation can be evaluated and addressed with applicable recommendations. The contractor and applicable subcontractors should familiarize themselves with this report prior to the start of their construction activities, contact Drash for any interpretation or clarification of the report, retain the services of their own consultants to interpret this report, or perform additional geotechnical testing prior to bidding and construction.

Unless stated otherwise in this report or in the contract documents between Drash and Client, our scope of services for this Project did not include, either specifically or by implication, any environmental or biological assessment of the site or buildings, or any identification or prevention of pollutants, hazardous materials or conditions at the site or within buildings. If the Client is concerned about the potential for such contamination or pollution, Drash should be contacted to provide a scope of services to address the environmental concerns. Also,


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permitting, site safety, excavation support, and dewatering requirements are the responsibility of others.

This geotechnical engineering report has been prepared for the exclusive use of our Client, the Clients’ design team and the project ownership group for specific application to this Project. This geotechnical engineering report has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, express or implied, are intended or made.

Should the nature, design, or location of the Project, as outlined in this geotechnical engineering report, be modified, geotechnical engineering recommendations and guidelines provided in this document will not be considered valid unless Drash reviews the changes and either verifies or modifies the applicable Project changes in writing.

EXHIBITS

EXHIBITDrawn By:

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Reviewed By:

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Date:

Scale:

Project No. PROJECT LOCATION MAP

NOT TO SCALE

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116G1178RK

SPG

1045 Central Parkway North, Suite 103 ▪ San Antonio, Texas 78232Office: 210.340.5004 ▪ Facsimile: 210.340.5009

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ESC

HERT

Z, C

OM

AL C

OU

NTY

, TEX

AS

RK

09/22

/2016

116G

1178

AB AB SPG

N

Exploratory Boring Location

B-2

SYMBOLS:

B-1

B-3

B-4

B-4

FLOWABLE FILL ORLEAN CONCRETE

FINISHED BUILDINGPAD ELEVATION (FBPE)

VERTICAL MOISTURE BARRIER

BEARING ELEVATION OF VMB 6.5 FT. BELOWTHE BOTTOM OF THE PERIMETER GRADE BEAM

10 MIL PVC VAPOR BARRIER CONTINUOUS WITHFLOOR SLAB VAPOR BARRIER OR LAPPED ATLEAST TWO (2) FEET.

PAVEMENT

FINISHED FLOOR ELEVATION (FFE)

6" OF GRANULAR SELECT FILL

ELEVATION TO BE DETERMINED BYPROJECT STRUCTURALENGINEER

EXTEND 10 MIL VAPOR BARRIERAT LEAST 36 INCHES INSIDEFOUNDATION BEAM

8 FT. FROMFBPE

ON-SITE SOILS

-0.5 FT.FROM FBPE

LEAN CLAY SELECT FILL7.5 FT.

SUBGRADE, SUBBASEOR BASE MATERIAL

EXHIBITDrawn By:

Checked By:

Reviewed By:

Project Mngr:

Date:

Scale:

Project No. VERTICAL MOISTURE BARRIER (VMB) DETAIL

NOT TO SCALE

09-22-2016

116G1178RK

SPG

1045 Central Parkway North, Suite 103 ▪ San Antonio, Texas 78232Office: 210.340.5004 ▪ Facsimile: 210.340.5009

3

N

AB

AB

TEXAS PLUMBING SUPPLYRED IRON AND PIPESTONE

SCHERTZ, COMAL COUNTY, TEXASTBPE Firm Registration F-13654

46

42

38

39

94

95

LAYER 1FAT CLAY (CH); dark brown; medium stiff to hard; with

roots in upper 2 feet - light brown with gray mottling below 2 feet

- with ferrous stains

Boring Terminated at 35 feet.

68

64

57

59

106

112

108

N=4

P=2.3

P=2.5

P=4.5+

P=4.5+

P=4.5+

P=4.5+

P=4.5+

P=3.8

P=4.5+

24

24

22

23

22

19

21

19

20

20

22

22

19

20

2.37

3.81

6.01

LOG OF BORING

PROJECT NO.BORING NO.

DATESURFACE ELEVATION

REMARKS

N: B

LOW

S/F

TP

: TO

NS

/SQ

FT

T: T

ON

S/S

Q F

TP

ER

CE

NT

RE

CO

VE

RY

/R

OC

K Q

UA

LIT

Y D

ES

IGN

AT

ION

The boring was backfilled with soil cuttings after completion of the subsurfacewater level observations.

116G

1178

- T

exas

Plu

mbi

ng S

uppl

y -

Thi

s Lo

g is

not

val

id if

sep

erat

ed f

rom

ori

gina

l rep

ort

.

SO

IL S

YM

BO

L

3

EXHIBIT

116G1178B-1

9/14/2016Existing Grade

FA

ILU

RE

ST

RA

IN (

%)

MIN

US

NO

. 200

SIE

VE

(%

)

LIQ

UID

LIM

IT

PLA

ST

IC L

IMIT

PLA

ST

ICIT

Y IN

DE

X

PROJECT:

LLDE

PT

H (

FT

)

Dry augered from 0 to 35 feet.

Subsurface water was not encountered during drilling.

PAGE 1 OF 1

ATTERBERGLIMITS (%)

LABORATORY DATAFIELD DATA

DR

Y D

EN

SIT

Y

(PO

UN

DS

/CU

FT

)

,CLIENT:

GROUNDWATER INFORMATION:

PL

5

10

15

20

25

30

35

DRILLING METHOD(S):

PISA

MP

LES

CO

MP

RE

SS

IVE

ST

RE

NG

TH

(TO

NS

/SQ

FT

)

CO

NF

ININ

G P

RE

SS

UR

E

(PO

UN

DS

/SQ

IN)

DESCRIPTION OF STRATUMMO

IST

UR

E C

ON

TE

NT

(%

)

Texas Plumbing SupplySchertz, Comal County, Texas

abakane

Biltmore Construction & Development San Antonio, Texas

54

51

43

37

95

LAYER 1FAT CLAY (CH); very dark brown; medium stiff to hard;

with roots in upper 2 feet

- gray between 4 and 6 feet

- light brown with gray mottling below 6 feet

- with ferrous stains


82

73

60

53

113

110

P=2.0

P=2.5

P=2.3

P=4.0

P=4.5+

P=4.5+

P=4.5+

P=4.5+

P=4.5+

P=4.5+

33

33

26

22

21

19

19

18

22

20

28

22

17

16

6.49

6.15

LOG OF BORING



REMARKS

N: B

LOW

S/F

TP

: TO

NS

/SQ

FT

T: T

ON

S/S

Q F

TP

ER

CE

NT

RE

CO

VE

RY

/R

OC

K Q

UA

LIT

Y D

ES

IGN

AT

ION


116G

1178

- T

exas

Plu

mbi

ng S

uppl

y -

Thi

s Lo

g is

not

val

id if

sep

erat

ed f

rom

ori

gina

l rep

ort

.

SO

IL S

YM

BO

L

4

EXHIBIT

116G1178B-2


FA

ILU

RE

ST

RA

IN (

%)

MIN

US

NO

. 200

SIE

VE

(%

)

LIQ

UID

LIM

IT

PLA

ST

IC L

IMIT

PLA

ST

ICIT

Y IN

DE

X

PROJECT:

LLDE

PT

H (

FT

)



PAGE 1 OF 1

ATTERBERGLIMITS (%)


DR

Y D

EN

SIT

Y

(PO

UN

DS

/CU

FT

)

,CLIENT:


PL

5

10

15

20

25

30

35

DRILLING METHOD(S):

PISA

MP

LES

CO

MP

RE

SS

IVE

ST

RE

NG

TH

(TO

NS

/SQ

FT

)

CO

NF

ININ

G P

RE

SS

UR

E

(PO

UN

DS

/SQ

IN)


IST

UR

E C

ON

TE

NT

(%

)


abakane


48LAYER 1FAT CLAY (CH); very dark gray; medium stiff to stiff;

trace of roots


76N=7

N=7

N=9

32

33

24

28

LOG OF BORING



REMARKS

N: B

LOW

S/F

TP

: TO

NS

/SQ

FT

T: T

ON

S/S

Q F

TP

ER

CE

NT

RE

CO

VE

RY

/R

OC

K Q

UA

LIT

Y D

ES

IGN

AT

ION


116G

1178

- T

exas

Plu

mbi

ng S

uppl

y -

Thi

s Lo

g is

not

val

id if

sep

erat

ed f

rom

ori

gina

l rep

ort

.

SO

IL S

YM

BO

L

5

EXHIBIT

116G1178B-3


FA

ILU

RE

ST

RA

IN (

%)

MIN

US

NO

. 200

SIE

VE

(%

)

LIQ

UID

LIM

IT

PLA

ST

IC L

IMIT

PLA

ST

ICIT

Y IN

DE

X

PROJECT:

LLDE

PT

H (

FT

)



PAGE 1 OF 1

ATTERBERGLIMITS (%)


DR

Y D

EN

SIT

Y

(PO

UN

DS

/CU

FT

)

,CLIENT:


PL

5

DRILLING METHOD(S):

PISA

MP

LES

CO

MP

RE

SS

IVE

ST

RE

NG

TH

(TO

NS

/SQ

FT

)

CO

NF

ININ

G P

RE

SS

UR

E

(PO

UN

DS

/SQ

IN)


IST

UR

E C

ON

TE

NT

(%

)


abakane


49

LAYER 1FAT CLAY (CH); very dark gray; medium stiff to stiff;

trace of roots


74

N=6

N=7

N=8

35

32

31 25

LOG OF BORING



REMARKS

N: B

LOW

S/F

TP

: TO

NS

/SQ

FT

T: T

ON

S/S

Q F

TP

ER

CE

NT

RE

CO

VE

RY

/R

OC

K Q

UA

LIT

Y D

ES

IGN

AT

ION


116G

1178

- T

exas

Plu

mbi

ng S

uppl

y -

Thi

s Lo

g is

not

val

id if

sep

erat

ed f

rom

ori

gina

l rep

ort

.

SO

IL S

YM

BO

L

6

EXHIBIT

116G1178B-4


FA

ILU

RE

ST

RA

IN (

%)

MIN

US

NO

. 200

SIE

VE

(%

)

LIQ

UID

LIM

IT

PLA

ST

IC L

IMIT

PLA

ST

ICIT

Y IN

DE

X

PROJECT:

LLDE

PT

H (

FT

)



PAGE 1 OF 1

ATTERBERGLIMITS (%)


DR

Y D

EN

SIT

Y

(PO

UN

DS

/CU

FT

)

,CLIENT:


PL

5

DRILLING METHOD(S):

PISA

MP

LES

CO

MP

RE

SS

IVE

ST

RE

NG

TH

(TO

NS

/SQ

FT

)

CO

NF

ININ

G P

RE

SS

UR

E

(PO

UN

DS

/SQ

IN)


IST

UR

E C

ON

TE

NT

(%

)


abakane


APPENDIX

Exploratory Drilling Program Laboratory Testing Program

Notes Regarding Soil and Rock

EXPLORATORY DRILLING PROGRAM A truck-mounted, drilling rig was used to drill the exploratory borings and to recover soil/rock samples during the drilling. Soil samples were obtained by a split-barrel (“split-spoon”) sampler while performing the Standard Penetration Test (“SPT”). When a soil/rock sample was recovered using a split-barrel sampler, the SPT N-value was recorded on the applicable field log. The SPT procedure consists of driving the split-barrel into the subsurface stratum with a 140-pound hammer falling a distance of 30 inches. The number of blows (“N”) required to advance the split-spoon sampler the last 12 inches during a normal 18-inch penetration is the SPT resistance value or N-value. These N-values are indicated on each applicable field log at the depths of occurrence. The samples were sealed and transported to the laboratory for testing and classification. Our field representative prepared the field logs as part of the drilling operations. The field logs included visual classifications of the materials encountered during drilling, our field representative interpretation of the subsurface conditions between samples, and recording the results of various tests (N-values, PPT, and TV) performed during drilling and sampling. Each field log included with this report represents our technical interpretation of the field log and includes modifications based on visual observations and testing of the samples in the laboratory. The scope of services for our geotechnical engineering services does not include addressing any environmental issues pertinent to the site.

LABORATORY TESTING PROGRAM Samples retrieved during the field exploration were taken to the laboratory for further observation by one of our technical representatives, and they were classified in accordance with the Unified Soil Classification System (USCS). At that time, the field descriptions were confirmed or modified as necessary and an applicable laboratory testing program was formulated to determine the physical (index) and engineering properties of the soil/rock. Laboratory tests were conducted on selected soil samples and the test results are presented in this appendix. The laboratory test results were used for the geotechnical engineering analyses, and the development of foundation and earthwork recommendations. Laboratory tests were performed in general accordance with the applicable ASTM or other accepted standards. The following tests were conducted:

• Moisture Content • Atterberg Limits • Amount of Material In-Soil Finer than the No 200 Mesh (75-µm) Sieve

Sample Disposal All samples were returned to our laboratory. Unless stated otherwise in this report or the Project contract, the samples not tested in the laboratory will be stored for a period of 30 days subsequent to submittal of this report and will be discarded after this period, unless other arrangements are made prior to the disposal period.

NOTES REGARDING SOIL AND ROCK

GEOTECHNICAL SAMPLING SYMBOLS: SS: Split Barrel (Split Spoon) ST: Thin-Walled Tube (Shelby tube) AG: Auger Sample, Grab Sample, or Bulk Sample

RC: Rock Coring Sample

WATER LEVEL MEASUREMENT SYMBOLS: Water Level Encountered While Drilling and Sampling. ▼ Water Level Measurement After Initial Water Level Encountered During Drilling and Sampling.

DESCRIPTIVE SOIL CLASSIFICATION: Soil classification is based on the Unified Soil Classification System (ASTM D2487). Coarse Grained Soils have more than 50 percent of their dry weight retained on a No. 200 sieve. The primary descriptors of these soils are: boulders, cobbles, gravel, or sand. In addition to gradation, coarse-grained soils are defined on the basis of their in-place relative density. Fine Grained Soils have less than 50 percent of their dry weight retained on a No. 200 sieve. These soils are principally described as clays if they are plastic (have binding/molding characteristics), and silts if they are slightly plastic or non-plastic. Fine-grained soils are defined on the basis of their consistency.

CONSISTENCY OF FINE-GRAINED SOILS RELATIVE DENSITY OF COARSE-GRAINED SOILS Undrained

Shear cu, psf

Standard Penetration Test (SPT) N-value

Blows Per Foot Consistency

Standard Penetration Test (SPT) N-Value

Blows Per Foot Relative Density < 250 < 2 Very Soft 0 – 3 Very Loose

250 – 500 2 - 3 Soft 4 – 9 Loose 500 – 1,000 4 - 6 Medium Stiff 10 – 29 Medium Dense

1,000 – 2,000 7 - 12 Stiff 30 – 49 Dense 2,000 – 4,000 13 - 26 Very Stiff 50+ Very Dense

4,000+ 26+ Hard

RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY

Descriptive Terms Percent of Dry Weight Major Constituent of

Soil Sample Particle Size Trace < 15 Boulders Over 12 in. (300mm) With 15 – 29 Cobbles 12 in. to 3 in. (300mm to 75 mm)

Modifier > 30 Gravel 3 in. to No. 4 sieve (75mm to 4.75 mm)

Sand

Silt or Clay No. 4 to No. 200 sieve (4.75mm to 0.075mm)

Passing No. 200 Sieve (0.075mm)

RELATIVE PROPORTIONS OF CLAYS AND SILTS PLASTICITY DESCRIPTION

Descriptive Terms Percent of Dry Weight Term Plasticity Index (PI) Trace < 5 Non-plastic 0 With 5 – 12 Low 1 - 10

Modifier > 12 Medium 11 - 30 High 30+

CLASSIFICATION OF ROCK WITH RESPECT TO STRENGTH

Very Low Strength 18 – 72 ksf Low Strength 72 – 288 ksf Medium Strength 288 – 1,152 ksf High Strength 1,152 – 4,608 ksf Very High Strength 4,608 – 18,432 ksf

RQD DESCRIPTION OF ROCK QUALITY 0 – 25 Very Poor

25 – 50 Poor 50 – 75 Fair 75 – 90 Good 90 - 100 Excellent

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