Attachment 6 - Geotech Report - Parking Structure - Martinez 03202025.pdf

Geotechnical Engineering Investigation MEL File No.: 2962 Proposed VA Martinez Clinical Building and Parking Garage March 8, 2019 150 Muir Road Martinez, CA Page 1 of 16

GEOTECHNICAL ENGINEERING INVESTIGATION

PROPOSED VA MARTINEZ CLINICAL BUILDING AND PARKING GARAGE

150 MUIR ROAD

MARTINEZ, CA

1. INTRODUCTION

1.1 GENERAL

The proposed VA Martinez Clinical Building and Parking Garage site is located at 150 Muir Road in Martinez, 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

We understand the proposed new clinical building and parking garage will be three-story in height. The existing structures and asphalt concrete paved parking are expected to be demolished for construction of the new buildings. No detailed grading plan is available at the time of this report writing. However, cut and fill is expected to achieve level building pads due to the gently sloping site grade.

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

VHAMACKallaU Text Box For Reference ONLY

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• 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 − Shallow foundation recommendations including allowable bearing capacity and anticipated total and differential settlements − 2016 California Building Code seismic design coefficients for use in structural analysis − Interior Concrete slab-on-grade − Exterior concrete sidewalk/flatwork − Retaining walls − Pavements − Surface drainage and moisture protection

• An appendix which includes a summary of our field investigation and laboratory programs

2. SUBSURFACE EXPLORATION AND LABORATORY TESTING

2.1 SUBSURFACE EXPLORATION

A subsurface exploration at the site was performed to investigate and sample soils beneath the site. Five exploratory borings (B1 to B5) to the approximate depths of 8.5 to 31 feet below the existing ground surface. The borings were drilled with a truck-mounted drill rig equipped with solid stem augers. Approximate locations of exploratory borings are shown on Plates 2. After completion of drilling, the bore holes were backfilled with cement slurry and topped with asphalt.

Obtained soil samples were sealed and transported to our Sacramento laboratory for visual examination and testing.

2.2 LABORATORY TESTING

Laboratory tests were performed on selected samples to evaluate physical properties of the soils which may affect the geotechnical aspects of project design and construction. Moisture content, dry density, compaction and soil corrosivity parameters tests were performed in general accordance with ASTM and Caltrans test methods. Results of the moisture content and dry density are presented in the Log of Boring. Laboratory test reports (compaction and soil corrosivity) are attached to this report in Appendix A.

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3. SITE CONDITIONS

3.1 SURFACE AND SUBSURFACE CONDITIONS

The project site is currently occupied by portable buildings with asphalt concrete paved parking as shown on Plate 1. The site grade slopes downwards gently to the northeast. Along the western site boundary line, the existing portable buildings are situated near the top of the retaining wall.

To the east of the project site is uneven landscaping separated by a walkway.

The site soils consist mainly of sand, clayey sand and clay to approximate depths of 13 to 25.5 feet underlain by weathered bedrock (sandstone or mudstone) to the maximum explored depth of 31 feet below the existing ground surface in B1, B2 and B5. Weathered sandstone was encountered near the ground surface (under asphalt pavement) in B3 and B4.

3.2 GROUNDWATER

At the time of our field investigation, no groundwater was encountered in any of our borings. 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 A2 to A6.

4. CONCLUSIONS AND RECOMMENDATIONS

4.1 EXPANSIVE SOILS

Based on the visual examination of the soil samples obtained at the subject site, the site soils are mainly sandy materials which are considered as having very low expansion potential.

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4.2 SOIL CORROSIVITY

Laboratory tests were performed for soil corrosivity parameters (minimum resistivity, pH, chloride and sulfate content) on two selected soil samples obtained from the site. Based on the test results, the tested soils are not considered to be corrosive to buried metallic improvements or have a significant corrosive potential to buried concrete structures. Therefore, Type II cement may be used. All underground utility lines should be corrosion-protected per recommendations of a corrosion engineer, if required.

We have provided the above preliminary corrosion test results only as 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.

4.3 SITE PREPARATION

4.3.1 Existing Pavements

We anticipate existing site pavements within the area of planned development will be demolished and removed from the site. Depending on site grading requirements, the contractor's capabilities, and other factors, it may be possible (and desirable) to process on-site pavements for reuse as engineered fill. Processing could involve pulverization, grinding, or other means. Regardless of the method used, for this material to be utilized as engineered fill, it must meet the applicable requirements provided below (see section titled "ENGINEERED FILL").

4.3.2 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. 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.

4.3.3 Demolition

Should any existing structures and utility lines within the area of construction be encountered, they 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. Tree removal should include the root system and all surface roots larger than 1/2-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.

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4.3.4 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, engineered fill placement and compaction.

Building Pad Area To provide uniform building support, following site stripping and any required grubbing and removal, the subgrade soils (except for fill areas) should be excavated to a depth of at least 12 inches below the design subgrade soil elevation. The exposed subgrade soils should be scarified to a depth of 12 inches, uniformly moisture-conditioned and compacted, then backfilled with engineered fill to the design subgrade elevation. The removal and compaction of the site soils should extend to a horizontal distance of at least 5 feet beyond the outer edge of foundations.

Non-Building Area In non-building area such as pavement, concrete sidewalk and flatwork, the subgrade soils should be scarified to a depth of at least 12 inches, uniformly moisture-conditioned and compacted. The scarification and compaction of the site soils should extend to a horizontal distance of at least 2 feet beyond the outer edge of pavement, concrete sidewalk/flatwork.

4.4 TEMPORARY EXCAVATION

Foundation excavations and shallow trenches less than five feet in depth for utilities should stand vertically for the short period of time required for temporary excavation under favorable weather conditions. Both bedrock and soil were encountered during our field exploration. Bedrock could be classified by OSHA’s standard as Type B with maximum allowable slope inclination of 1 : 1 (horizontal to vertical). Where soil is encountered above bedrock, it could be classified by OSHA’s standard as Type C with maximum allowable slope inclination of 1.5 : 1 (horizontal to vertical).

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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4.5 ENGINEERED FILL

4.5.1 Materials

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

On-Site Soils In general, near-surface on-site soils 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.

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.

4.5.2 Compaction Criteria

Soils scarified and material to be used for engineered fill should be uniformly moisture-conditioned to near 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 D1557. The upper 12 inches of subgrade in the parking / building pad area and all aggregate base materials should be compacted to a minimum of 95 percent relative compaction.

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.

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4.6 TRENCH PREPARATION AND BACKFILL

4.6.1 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.

4.6.2 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 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.

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.

4.6.3 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.

4.7 2016 CALIFORNIA BUILDING CODE SEISMIC DESIGN PARAMETER

Structures should be designed for lateral force requirements as set forth in Chapter 16 of the 2016 California Building Code (CBC). We recommend the parameters in the following Table 1:

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Table 1 2016 CBC Seismic Design Parameters

Seismic Design

Parameter

Symbol Recommended

Value Mapped Spectral Acceleration at Short Period

Ss 1.597g

Mapped Spectral Acceleration at 1-Second Period

S1 0.600g

Site Class A-F C

Site Coefficient at Short Period Fa 1.000

Site Coefficient at 1-Second Period Fv 1.300

Spectral Response Accelerations SMS 1.597g

SM1 0.780g

Design Spectral Response Accelerations SDS 1.064g

SD1 0.520g

Long-period Transition Period TL 8 seconds MCEG Peak Ground Acceleration Adjusted for Site Class Effects

PGAM 0.607g

Site coordinates: Latitude 37.9942 degrees North Longitude 121.1154 degrees West

4.8 SHALLOW FOUNDATIONS

4.8.1 Allowable Bearing Pressures

We recommend spread footings constructed of reinforced concrete and founded on engineered fill or undisturbed competent on-site soils/bedrock be used for support of the proposed building.

Footings should be a minimum of 18 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 3,500 pounds per square foot (psf) may be used for shallow 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 may be increased by 1/3 for short-term loading due to wind or seismic forces.

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The existing footings or retaining walls may experience an overall stress increase where located close to future foundations. Furthermore, stresses imposed by the new foundations on the utility lines may cause cracking, collapse and/or a loss of serviceability. To reduce this risk, new foundations should extend below a one horizontal to one vertical (1:1) plane projected upward from the closest bottom corner of the existing footing or trench.

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 1/2 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 0.35 may be used between cast-in-place concrete foundations and the underlying sandstone. Additional allowable passive pressure available may be taken as equivalent to the pressure exerted by a fluid weighing 350 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 or his representatives just prior to placing steel or concrete to verify the recommendations contained herein are implemented during construction.

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4.9 INTERIOR 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 6 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 depth. Proper and consistent location of the reinforcement at mid-slab is essential to its performance. The risk of uncontrolled shrinkage cracking is increased if the reinforcement is not properly located within the slab.

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) a vapor retarder may be placed 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 commonly applied, 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 moisture transmission rates will meet floor-covering manufacturer standards. The design and construction of such systems are dependent on the proposed use and design of the proposed building and all elements of building design and function should be considered in the slab-on-grade floor design. Building design and construction may have a greater role in perceived moisture problems since sealed buildings/rooms or inadequate ventilation may result in excessive moisture in a building and affect indoor air quality.

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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 EXTERIOR 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 RETAINING WALLS

4.11.1 Lateral Earth Pressures

Retaining walls should be deigned to resist the lateral earth pressures exerted by the retained, compacted backfill. Retaining walls that are not restrained at the top and with level backfill may be designed for an active lateral earth pressure and total lateral earth pressure (active plus seismic pressure increment) developed by an equivalent fluid weighing 40 pcf and 55 pcf, respectively. Retaining walls that are restrained at the top and with level backfill may be designed for an at-rest lateral earth pressure developed by an equivalent fluid weighing 60 pcf.

Thirty-five (35) percent of any uniform surcharge (located above an imaginary 45-degree line projected up from the bottom of a retaining wall) may be assumed to act as a uniform horizontal pressure over the entire height of the wall. Where vehicular traffic will pass within 10 feet of retaining wall, a uniform pressure of 100 psf should apply in the upper 10 feet of the walls.

4.11.2 Wall Drainage

The above-recommended values do not include lateral pressures due to hydrostatic forces.

Therefore, wall backfill should be free draining and provisions should be made to collect and dispose of excess water that may accumulate behind earth retaining structures.

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Wall drainage may be provided by free-draining gravel surrounded by synthetic filter fabric or by prefabricated, synthetic drain panels. In either case, drainage should be collected by perforated pipes and directed to a sump, storm drain, weep hole(s), or other suitable location for disposal.

We recommend drain rock consist of durable stone having 100 percent passing the 1-inch sieve and less than 5 percent passing the No. 4 sieve. Synthetic filter fabric should have an equivalent opening size (EOS), U.S. Standard Sieve, of between 40 and 70, a permeability of at least 0.02 centimeters per second, a minimum flow rate of 50 gallons per minute per square foot of fabric, and minimum puncture strength of 50 pounds.

4.11.3 Backfill Placement

All backfill should be placed and compacted in accordance with recommendations provided above for Engineered Fill. Light equipment should be used during backfill compaction to minimize possible overstressing of the wall.

4.11.4 Construction Considerations

Where the stability of adjoining buildings, walls, or other structures is endangered by excavation operations, support systems such as shoring, bracing, or underpinning may be required to provide structural stability and to protect personnel working within the excavation. Shoring, bracing, or underpinning required for the project (if any) should be designed by a professional engineer registered in the State of California.

4.12 PAVEMENTS

4.12.1 General

A design R-value of 35 was used in the design to derive the recommended pavement section. All pavement subgrades should be prepared as recommended in the SITE PREPARATION and ENGINEERED FILL sections of this report.

4.12.2 Asphalt Concrete Pavement Recommended Sections

Pavement sections presented in the Table 3 below are based on the current Caltrans design procedures. Traffic indexes of 4.5, 5.5, and 6.5 were assumed for the design of automobile parking areas, automobile driveways/access ways, and fire truck access ways, respectively. Traffic indexes assumed above should be reviewed by the project Owner, Architect, and/or Civil Engineer to evaluate their suitability for this project. Changes in the traffic indexes will affect the corresponding pavement section.

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Table 2 Recommended Asphalt Concrete Pavement Sections

Pavement Description

Assumed Traffic Index

Asphalt Concrete

(inch)

Caltrans Class 2 Aggregate Base

(inch)

Automobile Parking Areas 4.5 3 4

Automobile Driveways/Access Ways

5.5 3 7

Heavy Truck Access Ways 6.5 4 7

Asphalt paving materials and placement methods should meet current Caltrans specifications for asphalt concrete.

4.12.3 Portland Cement Concrete Pavement Sections

Portland cement concrete pavements are typically better able to resist the intense stresses induced in pavements by the turning motions of vehicles - particularly delivery and garbage trucks. Concrete pavements should be used in areas frequented by such vehicles as well as in driveway and entry aprons. Concrete pavement sections presented in the table below are based on current Portland Cement Association (PCA) design procedures and the assumptions listed below. These assumptions should be reviewed by the project Owner, Architect, and/or Civil Engineer to evaluate their suitability for this project. Changes in the assumptions will affect the corresponding pavement section.

Table 3 Recommended Concrete Pavement Sections

Pavement Description

Assumed Traffic Index

Portland Cement

Concrete (inch)

Caltrans Class 2 Aggregate Base

(inch)

Automobile Driveways/Access Ways

5.5 5 6

Heavy Truck Access Ways 6.5 7 6

The concrete should be properly cured in accordance with PCA recommended procedures and vehicular traffic should not be allowed for 3 days (automobile traffic) or 7 days (truck traffic). To help offset plastic shrinkage, concrete pavement may be reinforced, as a minimum, with at least No. 3 bars, 24 inches on-center, each way. Construction and/or control joint spacing should not exceed 12 feet. Thickened edges should be used along outside edges of concrete pavements. Edge

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4.12.4 Construction Consideration

The above pavement recommendations should be incorporated into project plans and specifications by the project architect and/or engineer. These recommendations are not intended to be used as a specification for construction. Adequate drainage (both surface and subsurface) should be provided such that the subgrade soils and aggregate base materials are not allowed to become wet.

4.13 SITE DRAINAGE AND MOISTURE PROTECTION

Foundation and slab performance depend 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 than the elevation of the subgrade beneath the slab to help prevent water intrusion beneath slabs. In any event, maintenance personnel should be instructed to limit irrigation to the minimum 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.

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5. ADDITIONAL SERVICES

5.1 PLANS AND SPECIFICATIONS REVIEW

We recommend that the ninety-five (95) percent complete plans and specifications should be reviewed by the Geotechnical Engineer of Record (GEOR), MatriScope to assure that our earthwork and foundation recommendations have been properly interpreted and implemented during design.

5.2 CONSTRUCTION OBSERVATION AND TESTING

All earthworks during construction should be monitored by the GEOR or his representatives, 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 that the finished subgrade and footing excavation in all areas to receive engineered fill or to be used for the future support of structures, concrete slabs-on-grade or pavement sections be observed and approved by GEOR prior to placement of engineered fill, concrete pouring or pavement placement.

The purpose of these services would be to provide GEOR 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

Conclusions and 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 construction, including the proposed loads or structural locations, 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 assume that an adequate program of tests and observations will be conducted by MatriScope or other qualified geotechnical

Martinez, CA Page 16 of 16 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.

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.

As GEOR of the subject project, MatriScope should review plans and specifications, and perform earthwork construction observation and testing to assure compliance with the recommendations presented in our report. Should the plan and specification review, construction observation and testing be performed by another party, MatriScope will assume no responsibility for misinterpretation or compliance with our recommendations. It is in the client’s interest and responsibility to secure a letter from the substitute testing laboratory/Geotechnical Engineer indicating that it is taking over the role of GEOR from MatriScope and assumes all responsibilities and liabilities. It should accept MatriScope’s conclusions/recommendations as its own conclusions/recommendations or modify as necessary and assure the construction in compliance with its own recommendations.

601 Bercut Drive Sacramento, CA 95811

Phone: (916) 375-6700

Fax: (916) 447-6702 www.matriscope.com

Project No.: 2962 Plate

Project Name: VA Martinez Clinical Building and Parking Garage

Location: 150 Muir Road, Martinez, California

Date: March 8, 2019

Site Vicinity Map

Site

Phone: (916) 375-6700

Fax: (916) 447-6702 www.matriscope.com

Project No.: 2962 Plate

Project Name: Proposed VA Martinez Clinical Building and Parking Garage

Location: 150 Muir Road, Martinez, CA

Date: March 8, 2019

Legend:

B1 Approximate Boring

Location

Base Map:

Sheet G002, General All

Utilities Layout, prepared by Advance Design

Consultants, Inc. dated

7/8/2015

B1

B2

B3

B4

B5

Boring

Location

Map

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APPENDIX A

FIELD INVESTIGATION AND LABORATORY TESTING

FIELD INVESTIGATION

General

The subsurface conditions at the site were explored on February 23, 2019 by drilling 5 borings to depths ranging from 8.5 to 31 feet below existing ground surface. Borings were drilled using a truck-mounted Simco 2400 drill rig equipped with 6-inch diameter solid stem augers. The locations of borings performed for this investigation are shown on Plate 2 of the report.

Borings were marked 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 in the field. After completion of drilling, the boreholes were backfilled with neat cement.

Our representative maintained logs of the borings, visually classified soils encountered in accordance with the Unified Soil Classification System (see Plate A1) and obtained relatively undisturbed and bulk samples of the subsurface materials. Logs of Boring are presented on Plates A2 to A6.

Sampling Procedures

Soil samples were obtained from the borings using a Modified California Sampler or Standard

Penetration Test (SPT) 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. 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.

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.

Martinez, CA Page 2 of 3

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. Moisture content was evaluated in general accordance with ASTM (American Society for Testing and Materials) Test Method D2216; dry unit weight was evaluated using procedures ASTM D2937. Results of these tests are presented on the logs of Borings.

Compaction

A compaction test was performed on a near-surface bulk soil sample to determine maximum dry density and optimum moisture content for use in evaluation of field soil compaction compliance during earthwork construction. Test procedures were in general accordance with ASTM D1557. Result of this test is presented in Table A1. The laboratory test report is attached.

Table A1 Compaction Test Result

Soil Corrosivity

Two soil samples were subjected to chemical analysis for corrosion potential assessment. The tests were performed in 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 A2. The laboratory test reports are attached in this appendix.

Table A2

Soil Corrosivity Test Results

Boring

No.

Sample Depth

(feet) pH

Minimum Resistivity

(Ohm-Cm)

Water Soluble

Chloride (ppm)

Water Soluble

Sulfates (ppm)

B2 0-5 6.82 2,950 2.8 104.1

B4 0-5 7.50 2,680 4.1 77.8

Boring No.

Sample Depth (feet)

Maximum Dry Density (pcf)

Optimum Moisture

B2 0-5 126.8 9.2

Martinez, CA Page 3 of 3

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 soil resistivity serves as an indicator parameter for possible presence of soluble salts. A minimum soil resistivity value less than 1,000 ohm-cm indicates the possible presence of higher quantities of soluble salts and a higher 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

Plate A1 to A6 Unified Soil Classification System and Log of Boring B1 to B5

Compaction Test Report

Soil Corrosivity Test Summary Reports

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

OL

CL

ML

MAJOR DIVISIONS

LETTER

PLATE

Sheet no.

Logged By Travis Boring Dia.

6"

MC 1-1 8

MC 1-2 12 13.3 103.2

MC 1-3 12

MC 1-4 9 13.9 104.2

MC 1-5 4

MC 1-6 25

MC 1-7 18

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

Drill Method Drill Equipment Solid Stem Auger Simco 2400

Depth to Groundwater N/A

Approx. Elevation (MSL) Notes

U

SC

S

SY

M B

O

LS

SA

M

P

LE

D

EP

TH

DESCRIPTION AND CLASSIFICATION

D

EP

TH

fe e t)

Sample Type

Started Completed Driller Total Depth 2/23/2019 2/23/2019 West Coast Exploration 31'

150 Muir Road, Martinez, CA 2962 YL

Proposed VA Martinez Clinical

Building and Parking Garage B1

Hole Number

LOG OF BORING

Site Location Project Number Checked By

Project

Modified California Sampler

SA

M

P

LE

N U

M B

ER

B

LO

W S/

M O

IS

TU

R E

D R

Y D

EN

SI

TY

(p cf

P

EN

ET

R

O M

ET

ER

(t sf

A2

Boring was ended at 31'. No groundwater was encountered.

CLAY, dark gray, moist, soft

CL

BEDROCK

WEATHERED MUDSTONE, olive brown, stiff

AC/AB

SAND, brown, fine to medium-grained, moist, dense

CLAYEY SAND, yellow-brown, moist, medium dense

SC

SP

19.5% passing #200 sieve

Logged By Travis Boring Dia.

6"

Simco 2400

MC 2-1 9 16.6 107.1

MC 2-2 10

MC 2-3 15 15 112.1

58/5"

MC 2-4 50/2"

MC 2-5 50/2"

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

Drill Method Drill Equipment Solid Stem Auger

Depth to Groundwater N/A

Approx. Elevation (MSL) Notes

U

SC

S

SY

M B

O

LS

SA

M

P

LE

D

EP

TH

DESCRIPTION AND CLASSIFICATION

D

EP

TH

fe e t)

Sample Type

Started Completed Driller Total Depth 2/23/2019 2/23/2019 West Coast Exploration 20.5'

150 Muir Road, Martinez, CA 2962 YL

Proposed VA Martinez Clinical

Building and Parking Garage B2

Hole Number

LOG OF BORING

Site Location Project Number Checked By

Project

Modified California Sampler

SA

M

M B

ER

B

LO

W S/

M O

IS

TU

D R

Y D

EN

P

EN

ET

R

O M

A3

Boring was ended at 20.5'. No groundwater was encountered.

No sample recovery

AC/AB

SAND, brown, fine to medium-grained, moist, dense

CLAYEY SAND, olive brown, very moist, dense

SP

BEDROCK

SC

WEATHERED SANDSTONE, yellow-brown, moist, very dense No sample recovery

Logged By Travis Boring Dia.

6"

Simco 2400

MC 3-1 50/1" 9.2

MC 3-2 55/3"

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

AC/AB

BEDROCK

No sample recovery, Refusal

WEATHERED SANDSTONE, yellow-brown, moist, very dense

Approx. Elevation (MSL) Notes

U

SC

S

SY

M B

O

LS

SA

M

P

LE

D

EP

TH

DESCRIPTION AND CLASSIFICATION

D

EP

TH

fe e t)

Sample Type

Started Completed Driller Total Depth 2/23/2019 2/23/2019 West Coast Exploration 10.5' Drill Method Drill Equipment Solid Stem Auger

Depth to Groundwater N/A

150 Muir Road, Martinez, CA 2962 YL

Proposed VA Martinez Clinical

Building and Parking Garage B3

Hole Number

LOG OF BORING

Site Location Project Number Checked By

Project

Modified California Sampler

SA

M

M B

ER

B

LO

W S/

M O

IS

TU

D R

Y D

EN

P

EN

ET

R

O M

Boring was ended at 10.5'. No groundwater was encountered.

A4

Logged By Travis Boring Dia.

6"

Simco 2400

MC 4-1 50/1"

SPT 4-2 50/1"

SPT 4-3 50/1"

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

Boring was ended at 8.5'. No groundwater was encountered.

A5

Modified California Sampler and SPT

SA

M

M B

ER

B

LO

W S/

M O

IS

TU

D R

Y D

EN

P

EN

ET

R

O M

Hole Number

LOG OF BORING

Site Location Project Number Checked By

Project

150 Muir Road, Martinez, CA 2962 YL

Proposed VA Martinez Clinical

Building and Parking Garage B4

Sample Type

Started Completed Driller Total Depth 2/23/2019 2/23/2019 West Coast Exploration 8.5' Drill Method Drill Equipment Solid Stem Auger

Depth to Groundwater N/A

Approx. Elevation (MSL) Notes

U

SC

S

SY

M B

O

LS

SA

M

P

LE

D

EP

TH

DESCRIPTION AND CLASSIFICATION

D

EP

TH

fe e t)

AC/AB

BEDROCK

WEATHERED SANDSTONE, yellow-brown, moist, very dense No sample recovery

No sample recovery

No sample recovery, Refusal

Logged By Travis Boring Dia.

6"

Simco 2400

MC 5-1 16 12.4 104.1

MC 5-2 10

MC 5-3 16 13.5 108.7

MC 5-4 15

50/2"

SPT 5-5 50/2"

SPT 5-6 50/1"

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

WEATHERED SANDSTONE, light brown, moist, very dense; thin mudstone interbeds brown

SP

AC/AB

SAND, light brown, fine-grained, moist, dense

BEDROCK

Approx. Elevation (MSL) Notes

U

SC

S

SY

M B

O

LS

SA

M

P

LE

D

EP

TH

DESCRIPTION AND CLASSIFICATION

D

EP

TH

fe e t)

Sample Type

Started Completed Driller Total Depth 2/23/2019 2/23/2019 West Coast Exploration 25.5' Drill Method Drill Equipment Solid Stem Auger

Depth to Groundwater N/A

150 Muir Road, Martinez, CA 2962 YL

Proposed VA Martinez Clinical

Building and Parking Garage B5

Hole Number

LOG OF BORING

Site Location Project Number Checked By

Project

Modified California Sampler and SPT

SA

M

M B

ER

B

LO

W S/

M O

IS

TU

D R

Y D

EN

P

EN

ET

R

O M

A6

Boring was ended at 25.5'. No groundwater was encountered.

No sample recovery

No sample recovery

Ph: 916-375-6700 fax: 916-447-6702 www.matriscope.com

JOB NO. LAB ID. DSA/LEA NO. DSA FILE NO. DSA APPLICATION NO. REPORT DATE

2962 19036 3/4/2019

MATERIAL DESCRIPTION

VA Martinez Clinical Building

PROCEDURE SIEVE_Oversize OVERSIZE < 5 %

B 3/8" Yes

TOTAL WT. (g) USED IN PROCESSING WT. (g) Oversize DRY (g) Oversize DRY (g) Finer TOTAL % Oversize TOTAL % Finer SG_Oversize

SAMPLING LOCATION SAMPLE DATE DIA. OF MOLD (in.) LAYERS BLOWS / LAYER HAND TAMPER

B2-Bulk 2/22/19 4 5 25 MECHANICAL TAMPER

A. WATER ADDED (CC) -100 -50 0 50 Finer Oversize

B. MOLD NUMBER

C. WT. OF WET SOIL + MOLD (gm) 4000.8 4101.6 4167.6 4086.1

D. WT. OF MOLD (gm) 2051.3 2051.3 2051.3 2051.3

E. WT. OF WET SOIL (gm) 1949.5 2050.3 2116.3 2034.8

F. VOLUME OF MOLD (ft ) 0.033 0.033 0.033 0.033

G. WET DENSITY (pcf) 129.1 135.8 140.1 134.7

H. CONTAINER NO. 0 A19 50 L1

I. WT. OF WET SOIL + TARE (gm) 824.0 801.9 732.8 896.5

J. WT. OF DRY SOIL + TARE (gm) 794.9 762.8 686.0 823.6

K. WT. OF TARE (gm) 284.6 285.7 233.7 284.0

L. WT. LOSS (gm) 29.1 39.1 46.8 72.9

M. WT. OF DRY SOIL (gm) 510.3 477.1 452.3 539.6

N. MOISTURE (%) 5.7 8.2 10.3 13.5

O. DRY DENSITY (pcf) 122.1 125.5 127.0 118.7

OPTIMUM WATER CONTENT 9.2

MAXIMUM DRY DENSITY 126.8

pcf

OPTIMUM WATER CONTENT

MAXIMUM DRY DENSITY

pcf

Technician

PROJECT

ADDRESS

150 Muir Road, Martinez, CA

COMPACTION CHARACTERISTICS OF SOIL

(ASTM D1557)

LABORATORY COMPACTION TEST

Brown Sand, medium to fine grain

Professional Engineer

TEST RESULTS

ROCK CORRECTED TEST RESULTS

REMARKS:

Soussan N. Ying-Chi Liao

0 2 4 6 8 10 12 14 16 18 20

D ry

D e n s it y p c f)

Water Content (%)

Compaction Curve http://www.matriscope.com/