Attachment J - 2472 VA Mather Primary Care Facility Geotechnical Report Combined.pdf

GEOTECHNICAL ENGINEERING INVESTIGATION

FOR

PROPOSED PRIMARY CARE BUILDING

VA MATHER HOSPITAL

10535 HOSPITAL WAY

MATHER, CALIFORNIA

PREPARED FOR

Mr. Lorenzo Rios Advance Design Consultants, Inc.

998 Park Avenue San Jose, CA 95126

By

Mr. Ying-Chi Liao, P.E., G.E.

Senior Geotechnical Engineer MatriScope Engineering Laboratories, Inc.

601 Bercut Drive Sacramento, California 95811

Project No. 2472 March 6, 2014

Geotechnical Engineering Investigation MEL File No. 2472 Proposed Primary Care Building March 6, 2015 VA Mather Hospital 10535 Hospital Way Mather, CA

TABLE OF CONTENTS

1. INTRODUCTION

1.1 GENERAL

1.2 PROPOSED CONSTRUCTION

1.3 PURPOSE AND SCOPE OF SERVICES

2. SITE REVIEW

2.1 RECONNAISSANCE

2.2 SUBSURFACE EXPLORATION

2.3 LABORATORY TESTING

3. SITE CONDITIONS

3.1 SURFACE AND SUBSURFACE CONDITIONS

3.2 GROUNDWATER

4. CONCLUSIONS AND RECOMMENDATIONS

4.1 GENERAL

4.2 EXPANSIVE SOILS

4.3 SOIL CORROSIVITY

4.4 SITE PREPARATION

4.4.1 Stripping and Grubbing

4.4.2 Existing Utilities, Foundations, and Landscaping

4.4.3 Removal, Scarification and Compaction

4.5 TEMPORARY EXCAVATION

4.6 ENGINEERED FILL

4.6.1 Materials

4.6.2 Compaction Criteria

4.7 TRENCH PREPARATION AND BACKFILL

4.7.1 Subgrade Preparation

4.7.2 Backfill Materials

4.7.3 Compaction Criteria

4.8 SPREAD FOUNDATIONS

4.8.1 Allowable Bearing Pressures

4.8.2 Estimated Settlements

4.8.3 Lateral Resistance

4.8.4 Construction Considerations

4.8.5 California Building Code Seismic Design Parameters

4.9 CONCRETE SLABS-ON-GRADE

4.9.1 Subgrade Preparation

4.9.2 Rock Capillary Break

4.9.3 Construction Considerations

4.10 CONCRETE SIDEWALKS AND FLATWORK

4.11 SITE DRAINAGE AND MOISTURE PROTECTION

5. ADDITIONAL SERVICES

5.1 PLANS AND SPECIFICATIONS REVIEW

VA Mather Hospital

Mather, CA

5.2 CONSTRUCTION OBSERVATION AND TESTING

6. LIMITATIONS

PLATES

APPENDIX A

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GEOTECHNICAL ENGINEERING INVESTIGATION

PROPOSED PRIMARY CARE BUILDING

VA MATHER MEDICAL HOSPITAL

10535 HOSPITAL WAY

MATHER, CA

1. INTRODUCTION

1.1 GENERAL

The proposed primary care building site is located at the southwest corner of the existing Building

650 at VA Mather Medical Hospital in Mather, California. This report contains the results of our geotechnical engineering investigation for the proposed development. The site location relative to the vicinity of the site is shown on Plate 1.

This report includes recommendations related to the geotechnical aspects of project design and construction. Conclusions and recommendations presented in this report are based on the subsurface conditions encountered at the locations of our field exploration and the provisions and requirements outlined in the ADDITIONAL SERVICES and LIMITATIONS sections of this report.

Recommendations presented herein should not be extrapolated to other areas or used for other projects without prior review by MatriScope Engineering Laboratories, Inc. (MatriScope).

1.2 PROPOSED CONSTRUCTION

The proposed site development includes a new two-story building at the site. The existing trailers at site will be removed. Grading plans were not available at the time this report was prepared;

however, as site topography is relatively level. Cuts and fills are expected to be 1 to 3 feet deep to make level building pads and insure proper drainage. Excavations for underground utilities are estimated to be about 3 to 5 feet below site grade.

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1.3 PURPOSE AND SCOPE OF SERVICES

Our field investigation was performed to explore and evaluate subsurface conditions at various locations at the site in order to develop recommendations related to the geotechnical aspects of project design and construction. This report summarizes the results of our services including:

A description of the proposed project

A description of the site surface, subsurface and groundwater conditions observed during our field investigation

Recommendations related to the geotechnical aspects of:

Site preparation and earthwork construction

Utility trench excavations and backfill

Spread footing design and construction

2013 CBC seismic design coefficients for use in structural analysis

Concrete slab-on-grade

Concrete sidewalks/flatwork

Surface drainage and moisture protection

2. SITE REVIEW

2.1 RECONNAISSANCE

An initial site reconnaissance was performed on February 6, 2015 to observe surface conditions that may affect the geotechnical aspects of the project and to note areas of obvious geotechnical concerns. Two (2) boring locations were marked at the project site.

2.2 SUBSURFACE EXPLORATION

A subsurface exploration at the site was performed to investigate and sample soils beneath the site. Two (2) exploratory borings (B1 and B2) were advanced to approximate depths of 10.5 and

6.5 feet below the existing ground surface in B1 and B2, respectively on February 14, 2015.

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“Refusal” (an indication of very firm soils) was encountered at the bottoms of both borings. The borings were drilled with a truck-mounted drill rig equipped with flight augers. Approximate locations of exploratory borings are shown on Plate 2.

After completion of drilling, the bore holes were backfilled with soil cuttings generated during drilling and capped with asphalt. The obtained soil samples were sealed and transported to our

Sacramento laboratory for visual examination and testing.

2.3 LABORATORY TESTING

Laboratory tests were performed on selected samples to aid in soil classification and to evaluate physical properties of the soils which may affect the geotechnical aspects of project design and construction. Moisture content, dry density, Expansion Index (EI), compaction, and soil corrosivity parameters tests were performed in general accordance with ASTM and Caltrans test methods.

Results of the moisture content, dry density and Expansion Index tests are presented in the Log of

Boring. Laboratory test reports (compaction testing, and soil corrosivity) are attached to this report.

3. SITE CONDITIONS

3.1 SURFACE AND SUBSURFACE CONDITIONS

The project site consists of an asphalt concrete paved area located at the southwest corner of the existing Building 650 at the site as shown in Plate 2. The site soils are mainly clays to the maximum explored depth of 10.5 feet below the existing ground surface. Some gravel was encountered at the bottoms of both borings. In general, the site soils are stiff to very stiff.

3.2 GROUNDWATER

At the time of our field investigation, no groundwater was encountered in any of our borings.

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It should be noted that soil moisture conditions within the site will vary depending on rainfall, and/or runoff conditions not apparent at the time of our field investigation. It is common that the soil moisture conditions will change seasonally.

Detailed descriptions of the subsurface conditions encountered during our field investigation are presented on the Log of Boring Plates A-2 and A-3.

4. CONCLUSIONS AND RECOMMENDATIONS

4.1 GENERAL

It is our professional opinion the proposed building may be supported on compacted engineered fill provided the recommendations contained in the attached report are implemented into project design and construction.

4.2 EXPANSIVE SOILS

Based on the result of Expansion Index test (EI of 19) performed on one near-surface soil sample obtained at the subject site, the site soils are considered as having low expansion potential.

4.3 SOIL CORROSIVITY

Laboratory tests were performed for soil corrosivity parameters (minimum resistivity, pH, chloride and sulfate content) on one selected soil sample obtained from the site. Based on the minimum resistivity test result (4,020 ohm-cm), soils are considered to have low corrosive potential to buried metallic improvements. Results of pH (6.67), chloride (11.6 ppm) and sulfate (68.8 ppm) content tests do not indicate a significant corrosive potential to buried concrete structures and, therefore, Type II cement may be used. All underground utility lines should be corrosion-protected per recommendations of a corrosion engineer, if required.

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We have provided the above preliminary corrosion test results. These test results are only indicator parameters of potential soil corrosivity for the sample tested. Other soils found on the site may be more, less, or of a similar corrosive nature.

4.4 SITE PREPARATION

4.4.1 Stripping and Grubbing

Prior to general site grading, existing vegetation, organic topsoil, and any debris should be stripped and disposed of outside the construction limits. We anticipate stripping operations may include the upper 6 to 12 inches of existing soils. MatriScope recommends the topsoil (less any debris) to be stripped and be stockpiled and reused for landscape purposes; however, this material should not be incorporated into any engineered fill.

4.4.2 Existing Utilities, Foundations, and Landscaping

The existing concrete slab and foundation and possibly abandoned utility lines within the area of construction should be removed and disposed of off-site. Existing utility pipelines that extend beyond the limits of the proposed construction and that are to be abandoned in-place should be plugged with cement grout to prevent migration of soil and/or water.

Landscaping removal should include the tree root system and all surface roots larger than ½-inch in diameter. All excavations resulting from removal of these items should be cleaned of loose or disturbed material (including all previously-placed backfill) and dish-shaped (with sides sloped 3

(h): 1(v) or flatter) to permit access for compaction equipment.

4.4.3 Removal, Scarification and Compaction

Preparation of the subgrade exposed by excavation and requirements for engineered fill should be in accordance with recommendations provided below (see section ENGINEERED FILL). The bottom of removal areas should be observed and approved by the geotechnical engineer or his representative prior to scarification and compaction.

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Following site stripping and any required grubbing, removal and/or over-excavation, we recommend the exposed excavation bottom should be scarified to a depth of at least 12 inches below the existing ground surface or the design finish subgrade elevation, whichever is lower;

uniformly moisture-conditioned and compacted as required in the ENGINEERED FILL section. If soft or unstable soils are encountered deeper than 12 inches, these soft soils should be over-excavated to a firm base and be replaced with engineered fill. The scarification and compaction of the site soils should extend to a horizontal distance of at least 5 feet beyond the outer edges of foundations.

4.5 TEMPORARY EXCAVATION

The site soils at the site should be excavatable with conventional equipment. Foundation excavations and shallow trenches less than five feet in depth for utilities should stand vertically for the short period of time required for construction under favorable weather conditions.

All excavations must comply with applicable local, state, and federal safety regulations including the current OSHA Excavation and Trench Safety Standards. Construction site safety generally is the sole responsibility of the Contractor, who shall also be solely responsible for the means, methods, and sequencing of construction operations. We are providing the information below solely as a service to our client. Under no circumstances should the information provided be interpreted to mean that MatriScope is assuming responsibility for construction site safety or the Contractor's activities; such responsibility is not being implied and should not be inferred.

During wet weather, earthen berms or other methods should be used to prevent runoff water from entering all excavations. All runoff water and/or groundwater encountered within the excavation(s) should be collected and disposed of outside the construction limits.

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4.6 ENGINEERED FILL

4.6.1 Materials

All engineered fill soils (on-site and imported soils) should be nearly-free of organic, rubble, rubbish, deleterious debris, or contaminated materials, and less than 3 inches in maximum dimension.

On-Site Soils

In general, near-surface, on-site soils similar to those encountered in our borings may be used in engineered fills provided they are free of deleterious debris, clays with high plasticity, organics and adequately moisture-conditioned during placement as recommended in the COMPACTION

CRITERIA section. The existing concrete and asphalt concrete debris may be removed offsite.

Imported Soils

All imported fill materials to be used for engineered fill should be sampled and tested by the project Geotechnical Engineer prior to being transported to the site. As a minimum, all imported fill should be free of contamination and be granular with a 3-inch maximum particle size, a

Plasticity Index less than 15 and less than 30 percent passing the number 200 sieve; essentially non-plastic. Imported gravel fill should be, as a minimum, washed gravel, free from vegetation and debris, with a 1-inch maximum particle size and less than 5 percent passing the number 200 sieve.

4.6.2 Compaction Criteria

Soils scarified and material to be used for engineered fill should be uniformly moisture-conditioned to between 3 to 5 percent above the optimum moisture content, placed in horizontal lifts less than 8 inches in loose thickness, and compacted to at least 90 percent relative compaction as determined by the current ASTM (American Society for Testing and Materials) Test

Method D 1557. The aggregate base materials should be compacted to a minimum of 95 percent relative compaction.

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Should site grading be performed during or subsequent to wet weather, near-surface site soils may be significantly above the optimum moisture content. Additionally, it is common to encounter wet, unstable soils upon removal of site pavements or flatwork as a result of subsurface moisture becoming trapped above relatively impervious hardpan or beneath asphalt concrete or

Portland cement concrete surfaces. This condition could hamper equipment maneuverability and efforts to compact site soils to the recommended compaction criteria. Disking to aerate, chemical treatment, replacement with drier material, stabilization with a geotextile fabric or grid, or other methods may be required to reduce excessive soil moisture and facilitate earthwork operations.

4.7 TRENCH PREPARATION AND BACKFILL

4.7.1 Subgrade Preparation

Prior to placement of utility bedding, the exposed subgrade at the bottom of trench excavations should be examined to detect soft, loose, or unstable areas. Loose materials at trench bottoms resulting from excavation disturbance should be removed to firm material. If soft or unstable areas are encountered, these areas should be over-excavated to a depth of at least 2 feet or to a firm base and be replaced with additional bedding material. Where excavations cross the existing trench backfill materials, the need for and extent of over-excavation or stabilization measures should be evaluated by the Geotechnical Engineer on a case-by-case basis.

4.7.2 Backfill Materials

Pipe zone backfill (i.e., material beneath and in the immediate vicinity of the pipe) should consist of clean washed sand and/or crushed rock. If crushed rock is used for pipe zone backfill, we recommend it should have a maximum particle size less 1 inch and have less than 5 percent passing No. 200 U.S. sieve. Where crushed rock is used, the material should be completed surrounded by a non-woven filter fabric such as Mirafi 140N or equivalent. Recommendations provided above for pipe zone backfill are minimum requirements only. More stringent material specifications may be required to fulfill local codes and/or bedding requirements for specific types of pipes. We recommend the project Civil Engineer develop these material specifications based on planned pipe types, bedding conditions, and other factors beyond the scope of this study.

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Trench zone backfill (i.e., material placed between the pipe zone backfill and finished subgrade) may consist of native soil and approved imported fill material that meets the requirements provided above for engineered fill.

4.7.3 Compaction Criteria

All trench backfill should be placed and compacted in accordance with recommendations provided above for engineered fill. Mechanical compaction is recommended; ponding or jetting should not be allowed, especially in areas supporting structural loads or beneath concrete slabs supported-on-grade, pavements, or other improvements.

4.8 SPREAD FOUNDATIONS

4.8.1 Allowable Bearing Pressures

We recommend spread footings constructed of reinforced concrete and founded on undisturbed competent on-site soils or newly constructed engineered fills as recommended in the SITE

PREPARATION section of this report be used for support of the proposed service building. Footings should be a minimum of 12 inches wide and embedded a minimum of 18 inches below the lowest final adjacent subgrade. The structural engineer should evaluate the need for reinforcement of foundation based on the anticipated loads. As a minimum, continuous foundations should be reinforced with a minimum of four No. 4 reinforcing bars, placed two each near the top and bottom, to provide structural continuity and allow the foundations to span isolated soil irregularities.

An allowable bearing pressure of 3,000 pounds per square foot (psf) may be used for spread foundations with the above minimum dimensions. The allowable bearing pressure provided above is a net value; therefore, the weight of the foundation (which extends below grade) may be neglected when computing dead loads. The allowable bearing pressure applies to dead plus live loads, includes a calculated factor of safety of 2, and may be increased by 1/3 for short-term loading due to wind or seismic forces.

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4.8.2 Estimated Settlements

Total settlement of an individual foundation will vary depending on the plan dimensions of the foundation and the actual load supported. Based on anticipated foundation dimensions and loads, we estimate maximum settlement of foundations designed and constructed in accordance with the preceding recommendations to be less than one inch. Differential settlement between similarly loaded, adjacent footings is expected to be less than ½ inch. Settlement of all foundations is expected to occur rapidly and should be essentially complete shortly after initial application of the loads.

4.8.3 Lateral Resistance

Resistance to lateral loads (including those due to wind or seismic forces) may be provided by frictional resistance between the bottom of concrete foundations and the underlying soils, and by passive soil pressure against the sides of the foundations. A coefficient of friction of 0.3 may be used between cast-in-place concrete foundations and the underlying soil. Additional allowable passive pressure available in engineered fill or undisturbed native soil may be taken as equivalent to the pressure exerted by a fluid weighing 300 pounds per cubic foot (pcf). These two modes of resistance should not be added unless the frictional component is reduced by 50 percent, since full mobilization of the passive resistance requires some horizontal movement, which significantly diminishes the frictional resistance.

4.8.4 Construction Considerations

Prior to placing steel or concrete, footing excavations should be cleaned of all debris, loose or soft soil, and water. All footing excavations should be observed by the project Geotechnical Engineer just prior to placing steel or concrete to verify the recommendations contained herein are implemented during construction.

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4.8.5 California Building Code Seismic Design Parameters

Structures should be designed for lateral force requirements as set forth in Chapter 16 of the 2013

California Building Code (CBC). We recommend the following parameters:

Table 1

2013 CBC Seismic Design Parameters

Seismic Design Parameter Symbol

Recommended Value

Mapped Spectral Acceleration at Short Period Ss 0.549g

Mapped Spectral Acceleration at 1-Second Period S1 0.261g

Site Class A-F D

Site Coefficient at Short Period Fa 1.361

Site Coefficient at 1-Second Period Fv 1.877

Spectral Response Accelerations SMS 0.747g

SM1 0.491g

Design Spectral Response Accelerations SDS 0.498g

SD1 0.327g

Long-period Transition Period TL 12 seconds

MCEG Peak Ground Acceleration Adjusted for Site Class Effects PGAM 0.259g

Site coordinates: Latitude 38.5720 degrees North Longitude 121.2970 degrees West

4.9 CONCRETE SLABS-ON-GRADE

Conventional concrete slab-on-grade floors are suitable for building pads provided excavations and subgrades are prepared as recommended in section titled SITE PREPARATION. Slab thickness and reinforcement should be determined by the structural engineer based on the anticipated loading. However, slabs should be at least 4 inches thick and reinforced with No. 3 reinforcing bars on 18 inches or No. 4 bars on 24 inches center-to-center spacing each way, placed at mid-slab

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4.9.1 Subgrade Preparation

Prior to constructing interior concrete slabs supported-on-grade, surficial soils should be processed as recommended in the SITE PREPARATION and ENGINEERED FILL sections of this report.

4.9.2 Rock Capillary Break

In order to provide enhanced subgrade support, we recommend the compacted subgrade be overlain with a minimum 4-inch thickness of compacted crushed rock. If this layer is desired to also serve as a capillary break, there should be less than 5 percent by weight passing the No. 4 sieve size. A capillary break may reduce the potential for soil moisture migrating upwards toward the slab.

4.9.3 Construction Considerations

Subsurface moisture and moisture vapor naturally migrate upward through the soil and, where the soil is covered by a building or pavement, this subsurface moisture will collect. To reduce the impact of this subsurface moisture and the potential impact of introduced moisture (such as landscape irrigation or plumbing leaks) the current industry standard is to place a vapor retarder on the compacted crushed rock layer (described above). This membrane typically consists of visquene or polyvinyl plastic sheeting at least ten (10) mil in thickness. The plastic sheet membrane should meet or exceed the minimum specifications for plastic water vapor retarders as outlined in ASTM E1745.

It should be noted that although capillary break and vapor barrier systems are currently the industry standard, this system may not be completely effective in preventing floor slab moisture problems. These systems will not "moisture proof" the floor slab nor will it assure floor slab

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Special precautions must be taken during the placement and curing of all concrete slabs. Excessive slump (high water-cement ratio) of the concrete and/or improper curing procedures used during either hot or cold weather conditions could lead to excessive shrinkage, cracking, or curling in the slabs. High water-cement ratio and/or improper curing also greatly increase the water vapor permeability of concrete. We recommend that all concrete placement and curing operations be performed in accordance with the current edition of American Concrete Institute (ACI) Manual.

4.10 CONCRETE SIDEWALKS AND FLATWORK

Concrete sidewalks and flatwork should be a minimum of 4 inches thick and may be underlain by compacted engineered fills as recommended in the SITE PREPARATION and ENGINEERED FILL sections of this report.

4.11 SITE DRAINAGE AND MOISTURE PROTECTION

Foundation and slab performance depends greatly on how well runoff waters drain from the site.

This drainage should be maintained both during construction and over the entire life of the project. The ground surface around structures should be graded so that water flows rapidly away from structures and slopes without ponding. The surface gradient needed to do this depends on the landscaping type. In general, pavement and lawns within five feet of buildings should slope away at gradients of at least two percent. Densely vegetated areas should have minimum gradients of 5 percent away from buildings in the first five feet if it is practical to do so.

Planters should be built so that water exiting from them will not seep into the foundation areas or beneath slabs and pavement. In general, the elevation of exterior grades should not be higher

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In any event, maintenance personnel should be instructed to limit irrigation to the minimum actually necessary to properly sustain landscaping plants. Should excessive irrigation, waterline breaks, or unusually high rainfall occur, saturated zones and "perched" groundwater may develop.

Consequently, the site should be graded so that water drains away readily without saturating the foundation or landscaped areas. Potential sources of water, such as water pipes, drains, garden sprinklers, and the like, should be frequently examined for signs of leakage or damage. Any such leakage or damage should be promptly repaired.

All utility trenches should be backfilled with compacted non-pervious fill material. Special care should be taken during installation of sub-floor water and sewer lines to reduce the possibility of leaks.

5. ADDITIONAL SERVICES

5.1 PLANS AND SPECIFICATIONS REVIEW

We recommend that grading plans and specifications should be reviewed by MatriScope in order to assure that our earthwork and foundation recommendations have been properly interpreted and implemented during design. In addition, prior to construction, the building structural design plans and specifications should be reviewed by MatriScope to verify the recommendations provided in this report are in compliance with the proposed design.

In the event MatriScope is not retained to perform this recommended review, we will assume no responsibility for misinterpretation of our recommendations.

5.2 CONSTRUCTION OBSERVATION AND TESTING

We recommend that all earthworks during construction be monitored by a representative from

MatriScope, including site preparation, placement of all engineered fill, trench backfill and wall backfill, construction of slab and roadway subgrade, and all foundation excavations. It is essential

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The purpose of these services would be to provide MatriScope the opportunity to observe the soil conditions encountered during construction, evaluate the applicability of the recommendations presented in this report to the soil conditions encountered, and recommend appropriate changes in design or construction procedures if conditions differ from those described herein.

6. LIMITATIONS

Recommendations contained in this report are based on our field observations and subsurface explorations, limited laboratory tests, and our present knowledge of the proposed construction. It is possible that soil conditions could vary between or beyond the points explored. If soil conditions are encountered during construction which differ from those described herein, we should be notified immediately in order that a review may be made and any supplemental recommendations provided. If the scope of the proposed site development changes from that described in this report, our recommendations should also be reviewed.

We have prepared this report in substantial accordance with the generally accepted geotechnical engineering practice as it exists in the site area at the time of our study. No warranty is expressed or implied. The recommendations provided in this report are based on the assumption that an adequate program of tests and observations will be conducted by MatriScope or other qualified geotechnical professionals during the construction phase in order to evaluate compliance with our recommendations. Other standards or documents referenced in any given standard cited in this report, or otherwise relied upon by the author of this report, are only mentioned in the given standard; they are not incorporated into it or “included by reference”, as that latter term is used relative to contracts or other matters of law.

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This report may be used only by the client and only for the purposes stated, within a reasonable time from its issuance. Land use, site conditions (both on site and off site) or other factors may change over time, and additional work may be required with the passage of time. Any party other than the client who wishes to use this report shall notify MatriScope of such intended use. Based on the intended use of the report, MatriScope may require that additional work be performed and that an updated report be issued. Non-compliance with any of these requirements by the client or anyone else will release MatriScope from any liability resulting from the use of this report by any unauthorized party.

Sacramento, CA 95811 Phone: (916) 375-6700 Fax: (916) 447-6702 www.matriscope.com

Project No.: 2472 Plate

Project Name: Proposed Primary Care Building

Location: 10535 Hospital Way, Mather, California

Date: 3/6/2015

Site Vicinity Map

Project Site

Sacramento, CA 95811 Phone: (916) 375-6700 Fax: (916) 447-6702 www.matriscope.com

Project No.: 2472 Plate

Project Name: Proposed Primary Care Building

Location: 10535 Hospital Way, Mather, CA

Date: 3/6/2015

Legend:

B1

Approximate Boring Location

Not to Scale

Boring Location Map

B1

B2

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APPENDIX A

FIELD INVESTIGATION AND LABORATORY TESTING

FIELD INVESTIGATION

General

The subsurface conditions at the site were explored on February 14, 2015 by drilling 2 borings to a maximum depth of 10.5 feet below existing ground surface. Borings were drilled using truck-mounted drill rig CME 75 equipped with 4-inch-diameter flight augers. The locations of borings performed for this investigation are shown on Plate 2 of the report.

Borings were located in the field by visual sighting and/or pacing from existing site features.

Therefore, the location of borings shown on Plate 2 should be considered approximate and may vary from that indicated on the plate. After completion of drilling, the boreholes were backfilled with the soil cutting generated during drilling with cold AC patching at each location.

Our representative maintained logs of the borings, visually classified soils encountered according to the Unified Soil Classification System (see Plate A1), and obtained relatively undisturbed and bulk samples of the subsurface materials. Logs of Borings are presented on

Plates A-2 and A-3.

Sampling Procedures

Soil samples were obtained from the borings using either a Modified California Sampler driven

18 inches (unless otherwise noted) into undisturbed soil using a 30-inch drop of a 140-pound hammer. Blow counts were recorded at 6-inch intervals for each sample attempt and are reported on the logs in terms of blows-per-foot for the last foot of penetration. Soil samples obtained from the borings were packaged and sealed in the field to reduce moisture loss and disturbance, and returned to our laboratory for further testing.

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LABORATORY TESTING

General

Laboratory tests were performed on selected samples to aid in soil classification and to evaluate physical properties of the soils which may affect the geotechnical aspects of project design and construction. A description of the laboratory testing program is presented below.

Moisture Content and Dry Unit Weight

Moisture content and dry unit weight tests were performed to evaluate moisture-conditioning requirements during site preparation and earthwork grading; soil overburden, and active and passive earth pressures; and relative soil strength and compressibility. Moisture content was evaluated in general accordance with ASTM Test Method D2216; dry unit weight was evaluated using procedures similar to ASTM Test Method D2937. Results of these tests are presented on the logs of Borings.

Expansion Index

Expansion Index (EI) test was performed on one remolded, fine-grained soil sample considered representative of the anticipated floor slab subgrade. Test procedures were in general accordance with ASTM Test Method D4829. Test result is shown in table A1. The tested soil, with an EI value of less than 20, is considered having a very low expansion potential based on

ASTM D4829.

Table A1

Summary of Expansion Index Test Results

Boring No. Sample Depth

(feet)

Expansion Index

B2 0-5 19

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Compaction

Compaction test was performed on one near-surface bulk soil sample to evaluate maximum dry density and optimum moisture content. Test procedures were in general accordance with

ASTM Test Method D1557. Results of this test are presented in Table A2. Laboratory test report is included in this appendix.

Table A2

Summary of Compaction Test Results

Soil Corrosivity

One sample of the near-surface soils encountered at the site was subjected to chemical analysis for the purpose of corrosion assessment. The sample was tested for pH, minimum resistivity, soluble sulfates, and soluble chlorides. The sample was tested in general accordance with

California Test Methods 643, 422, and 417 for pH and minimum resistivity, soluble chlorides, and soluble sulfates, respectively. The test results are presented in Table A3 and attached in this appendix.

Table A3

Summary of Corrosivity Test Results

Boring

No.

Sample

Depth (feet)

Minimum

Resistivity

(Ohm-Cm) pH

Water Soluble

Sulfates

(ppm)

Water Soluble

Chlorides

(ppm)

B2 0-5 4,020 6.67 68.8 11.6

Boring

No.

Sample Depth

(feet)

Maximum Dry Density

(pcf)

Optimum Moisture Content

B2 0-5 138.1 6.9

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The 2003 California Department of Transportation (Caltrans) Corrosion Guidelines considers a site to be corrosive if water-soluble chloride content is 500 ppm or greater, sulfate concentration is 2,000 ppm or greater, or pH is 5.5 or less.

The Corrosion Guidelines indicates resistivity serves only as an indicator parameter for the possible presence of soluble salts and is not used by Caltrans to define a corrosive area. With the exception of Mechanically Stabilized Embankment (MSE) walls, soil and water are not tested by Caltrans for chlorides and sulfates if the minimum resistivity is greater than 1,000 ohm-cm because a minimum resistivity greater than 1,000 ohm-cm indicates that the chloride and sulfate contents are low (i.e. low corrosion potential).

We have provided the above preliminary corrosion test results. These test results are only indicator parameters of potential soil corrosivity for the sample tested. Other soils found on the site may be more, less, or of a similar corrosive nature.

LIST OF ATTACHMENTS

The following plates are attached and complete this appendix.

Plate A-1 Unified Soil Classification System

Plates A-2 and A-3 Log of Boring B-1 and B-2

Compaction Test Report

Corrosivity Test Summary

WELL-GRADED SANDS, GRAVELLY

SANDS, LITTLE OR NO FINES

GP

GRAPH

INORGANIC CLAYS OF HIGH

PLASTICITY

TYPICAL

DESCRIPTIONS

WELL-GRADED GRAVELS, GRAVEL -

SAND MIXTURES, LITTLE OR NO

FINES

GRAVELS WITH

FINES

SYMBOLS

CLAYEY GRAVELS, GRAVEL - SAND -

CLAY MIXTURES

POORLY-GRADED SANDS,

GRAVELLY SAND, LITTLE OR NO

FINES

NOTE: DUAL SYMBOLS ARE USED TO INDICATE BORDERLINE SOIL CLASSIFICATIONS

GC

MORE THAN 50%

OF MATERIAL IS

LARGER THAN

NO. 200 SIEVE

SIZE

MORE THAN 50%

OF MATERIAL IS

SMALLER THAN

NO. 200 SIEVE

SIZE

MORE THAN 50%

OF COARSE

FRACTION

PASSING ON NO.

4 SIEVE

MORE THAN 50%

OF COARSE

FRACTION

RETAINED ON NO.

4 SIEVE

SILTY SANDS, SAND - SILT

MIXTURES

(LITTLE OR NO FINES)

GM

SOIL CLASSIFICATION CHART

SAND

AND

SANDY

SOILS

INORGANIC CLAYS OF LOW TO

MEDIUM PLASTICITY, GRAVELLY

CLAYS, SANDY CLAYS, SILTY CLAYS,

LEAN CLAYS

ORGANIC SILTS AND ORGANIC

SILTY CLAYS OF LOW PLASTICITY

GW

HIGHLY ORGANIC SOILS

SC

SM

SP

COARSE

GRAINED

SOILS

SW

INORGANIC SILTS, MICACEOUS OR

DIATOMACEOUS FINE SAND OR

SILTY SOILS

GRAVEL

AND

GRAVELLY

SOILS

(APPRECIABLE

AMOUNT OF FINES)

(APPRECIABLE

AMOUNT OF FINES)

CLAYEY SANDS, SAND - CLAY

MIXTURES

INORGANIC SILTS AND VERY FINE

SANDS, ROCK FLOUR, SILTY OR

CLAYEY FINE SANDS OR CLAYEY

SILTS WITH SLIGHT PLASTICITY

FINE

GRAINED

SOILS

SILTS

AND

CLAYS

SILTS

AND

CLAYS

SILTY GRAVELS, GRAVEL - SAND -

SILT MIXTURES

ORGANIC CLAYS OF MEDIUM TO

HIGH PLASTICITY, ORGANIC SILTS

POORLY-GRADED GRAVELS,

GRAVEL - SAND MIXTURES, LITTLE

OR NO FINES

CLEAN SANDS

A-1

OH

PEAT, HUMUS, SWAMP SOILS WITH

HIGH ORGANIC CONTENTS

CLEAN

GRAVELS

(LITTLE OR NO FINES)

SANDS WITH

FINES

LIQUID LIMIT

LESS THAN 50

LIQUID LIMIT

GREATER THAN 50

PT

601 Bercut Drive Sacramento, CA 95811 Phone: (916) 375-6700 Fax: (916) 447-6702

CH

MH

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CL

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