Appendix D-1 Geotechnical Report

DESIGN LEVEL GEOTECHNICAL INVESTIGATION PROPOSED RESIDENTIAL DEVELOPMENT TENNYSON PROPERTY - APN: 078C-0461-001-13 TENNYSON EAST OF MISSION BOULEVARD HAYWARD, CALIFORNIA

FOR The Grupe Company 3255 West March Lane Stockton, California 95219

October 17, 2017

Job No. 3823.102

BERLOGAR STEVENS & ASSOCIATES

Design Level Geotechnical Investigation Proposed Residential Development Tennyson Property - APN: 078C-0461-001-13 Tennyson Road East of Mission Boulevard Hayward, California

TABLE OF CONTENTS

INTRODUCTION ...... 1 Purpose And Scope...... 1 Project Understanding ...... 1 Site Location and Description ...... 2 ...... 3 Regional And Local Geology ...... 3 Artificial Fill ...... 4 Deposits ...... 4 Faulting ...... 4 SITE INVESTIGATION ...... 4 Field Exploration ...... 4 Geotechnical Laboratory Testing ...... 5 Subsurface Conditions ...... 6 ...... 6 ...... 6 ...... 6 GEOLOGIC AND SEISMIC HAZARDS ...... 7 Fault Rupture ...... 7 Seismic Shaking and Seismic Design Parameters ...... 7 -Induced Landslide Potential ...... 9 Liquefaction Potential ...... 9 CONCLUSIONS AND RECOMMENDATIONS ...... 9 General ...... 9 Site Design Considerations ...... 10 Building Setbacks from Slopes ...... 10 Surface Drainage ...... 10 Subsurface Drainage ...... 11 Bioretention Areas ...... 11 Slope Stability ...... 12 Static Slope Stability ...... 12 Pseudo-Static Slope Stability ...... 12 Graded Slopes ...... 13 Slopes ...... 13 Fill Slopes ...... 13 Erosion Protection ...... 15 Remedial ...... 15 Residual Removal ...... 15 Uncontrolled Fill ...... 15 Differential Fill on Building Pads ...... 15 Landslide Repair ...... 16 Decoupling Section ...... 16 Expansive Soils ...... 16 Excavation Characteristics ...... 16 Fill Materials ...... 16 Site Preparation And Grading...... 17

BERLOGAR STEVENS & ASSOCIATES

Utility ...... 19 Trenches Adjacent to Building Foundations ...... 19 Excavation ...... 19 Groundwater Considerations ...... 20 Backfill ...... 20 Building Pad Pre-soak ...... 21 Landscaping and Landscape Irrigation ...... 21 Building Foundations ...... 22 Foundation Decoupling ...... 22 Post-Tensioned Slab-On- Foundation Design Parameters ...... 23 Additional Design and Considerations ...... 23 Moisture Vapor Transmission through Interior Slabs-On-Grade ...... 24 Retaining Walls ...... 24 Conventional or Concrete Masonry ...... 24 Mechanically Stabilized Earth Retaining Wall ...... 26 Wall Surcharge ...... 27 Retaining Wall Backdrains ...... 27 Retaining Wall Backfill ...... 28 Concrete Flatwork ...... 28 Structural Pavement...... 29 Flexible Pavement ...... 29 Materials ...... 30 Seepage Cut-Off And Pavement Section Drainage ...... 31 ADDITIONAL SERVICES ...... 31 Remedial Grading Plan ...... 31 Review of Plans and Specifications ...... 31 Earthwork and Paving Observation and Testing ...... 31 LIMITATIONS ...... 32

PLATES Plate 1 – Vicinity Map Plate 2 – Site Plan Plate 3 – Fill Slope and Keyway Detail Plate 4 – Typical Subdrain Details Plate 5 – Pavement Edge Drain Detail Plate 6 – Foundation Decoupling Detail Plate 7 – Retaining Wall Backdrain Detail Plates 8-11 –

APPENDICES Appendix A – Boring Logs and Boring Log Key Appendix B – Exploratory Test Pit and Logs - BSA Appendix C – Exploratory Trench Logs - Engeo Appendix D – Geotechnical Laboratory Test Results

BERLOGAR STEVENS & ASSOCIATES

October 17, 2017 Job No. 3823.102 Page 1 PROPOSED RESIDENTIAL DEVELOPMENT TENNYSON PROPERTY - APN: 078C-0461-001-13 TENNYSON ROAD EAST OF MISSION BOULEVARD HAYWARD, CALIFORNIA

INTRODUCTION

PURPOSE AND SCOPE

The purpose of this study was to further investigate the geologic and geotechnical subsurface conditions at the site and to provide geotechnical conclusions and recommendations based on those conditions for use in the design and construction of the proposed project. The scope of our services was in general accordance with our proposal of February 2, 2017 and included the following:

1. Review of conceptual site plans prepared by Rodgers, Inc. (provided by E-Mail on June 7, 2017). 2. Site reconnaissance by a member of our engineering staff. 3. Marking of borings and test pit locations, and USA North notification. 4. Obtaining a drilling permit from Alameda County Public Works Agency- Resources. 5. Exploration of subsurface conditions by drilling soil-test borings and the excavation of test pits. 6. Geotechnical laboratory testing to assess the physical properties of selected soil samples collected during the field exploration. 7. Engineering analysis. 8. Preparation of this report.

PROJECT UNDERSTANDING

It is our understanding that the current concept is for a residential development with multi-family attached structures. Concept drawings for the site depict a terraced site with two levels. The upper level of the development will have a single loaded street, with a double-loaded street at the lower level. The conceptual plans show retaining walls or retaining walls with slopes above the wall between the two levels of the site. Grading of the site will result in both slopes with slope heights up to about 20 feet. Retaining walls are also shown along the southeast side of the site to maximize the density given the site constraints and the need to limit slope inclinations as discussed below. The conceptual plans show duplex and triplex buildings. The structures are expected to be two- to three-story wood-frame buildings, constructed at-grade and supported by

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 2 structural -on-grade foundations. Structures of this type are generally relatively lightly loaded; a uniform bearing pressure of 400 pounds per square foot (psf) is assumed.

The project will also include construction of new underground utilities and roadways. Site access will be by way of a new roadway from Tennyson Boulevard, located to the west of the site, entering the site at the northwest corner of the property. A culvert or bridge will be required to cross an existing drainage at the northwest end of the planned development.

There are two designated wetland areas north of the proposed area of development. The wetland areas and the area of the property located to the east of the proposed development, which contains a third wetland area, will remain as open-space.

SITE LOCATION AND DESCRIPTION

The project site lies on the west flank of the East Bay Hills on a low ridge of foothills overlooking the broad alluvial plain about six miles northeast of the San Francisco Bay. The approximately 15½-acre, roughly triangular-shaped southwest sloping property (Assessor’s Parcel Number 078C-0461-001-13), which was previously referred to as the “Ersted Property,” is located about 450 feet east of Mission Boulevard and south of the former La Vista Quarry in Hayward (Vicinity Map, Plate 1). The parcel is about 1,500 feet deep and is elongated in a northeastern direction, narrowing toward the northeast. A narrow strip of undeveloped land separates the site from commercial buildings along Mission Boulevard to the southwest.

The United States Geologic Survey 7½-minute Hayward quadrangle topographic map (USGS, 1980) indicates that the property ranges from an elevation of about 50 feet above mean-sea-level (msl) in its southern corner to about 265 feet in its northwestern corner. The area identified by BSA as potentially developable (BSA 2017) is generally located between elevation 110 feet and 165 feet msl. The site slopes down to the west and south with slopes ranging from as steep as about 2-¼ Horizontal to 1 Vertical (2-¼ H:1V) to as flat as about 8H:1V. The property has been extensively modified by grading or quarrying in the central area of the parcel. Quarry activities resulted in the removal of the natural soil cover in the central and northeast eastern portions of the site. The grading activities also resulted in varying amounts of artificial fill. Surface drainage is concentrated in two incised drainage courses near the northern and southern boundaries of the property.

Existing vegetation within and adjacent to the development area is predominantly dense seasonal grasses with a few scattered palm and willow trees. Two wetlands areas have developed along the northwestern side of the site. It appears that water diverted to the site during past quarry operations upslope of the site, water currently directed toward the site from subdrains installed during grading of the upslope site, and current construction of the extension of Tennyson Road are contributing factors in the development of the wetlands. A linear stand of eucalyptus trees is located along the southwestern property line.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 3 GEOLOGY

REGIONAL AND LOCAL GEOLOGY

The City of Hayward and the subject property are located within the Coast Ranges Geomorphic Province. The province consists of a series of discontinuous northwest trending mountain ranges, ridges, and intervening valleys characterized by complex folding and faulting. Geologic and geomorphic structures within the San Francisco Bay Area are dominated by the San Andreas fault system, a right-lateral strike-slip transform boundary that extends from the Gulf of California in Mexico, to Cape Mendocino in Humboldt County, California. It forms a portion of the boundary between two independent tectonic plates. To the west of the San Andreas fault system is the Pacific plate, which moves north relative to the North American plate, located east of the fault system. In northern California, movement across this plate boundary is concentrated on the San Andreas fault. However, a portion of the movement is also distributed across a number of faults including the Hayward, Calaveras, San Gregorio, Paicines, Zayante-Vergeles, and Quien Sabe among others. Together, these faults are referred to as the San Andreas fault system.

The project site is underlain by basement rock consisting of a complicated mixture of metamorphosed rocks of the Franciscan Complex derived from deformed and accreted seafloor rocks. Structurally adjacent to or unconformably overlying the Franciscan are marine sedimentary rocks of the Great Valley Group deposited during Jurassic and Cretaceous time. The Great Valley Group in the area of study on the site is mantled by alluvial fan and colluvial materials shed from the hills to the east. Mapping by Graymer and others (1995) of the USGS indicates that the portion of the site proposed for development is underlain by the Jurassic Age Knoxville Formation of the Great Valley Group. These two bedrock units date to the Jurassic to Cretaceous Periods. Their rocks were extensively fractured and sheared, and some were slightly metamorphosed by subduction processes that stopped operating in this part of California several million years ago.

The sedimentary rocks, consisting of conglomerate, sandstone, and shale, are generally assigned to the Knoxville Formation, and the volcanic rocks, consisting of slightly metamorphosed basalt (greenstone), are assigned to the Franciscan Complex. The Knoxville Formation is comprised mainly of dark, greenish-gray or shale with thin sandstone interbeds. Thick pebble to cobble conglomerate beds are present in the lower part of the Knoxville Formation. Exposures of the Knoxville Formation are generally weak to moderately strong, highly fractured to crushed, and thinly bedded. Franciscan Complex rocks are more or less sheared and metamorphosed graywacke, shale, mafic volcanic rock, chert, ultramafic rock, limestone, and conglomerate. Highly sheared sandstone and shale forms the matrix of a mélange containing blocks of many rock types, including sandstone, chert, greenstone, blueschist, serpentinite, eclogite, and limestone (USGS, 2000).

Residual soil, which is residual natural soil derived by weathering of the underlying parent bedrock, overlaps the bedrock and underlies the valley floor west of the site where elevations are

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 4 below 50 feet. The residual soils generally consisted of dark brown to red-brown, dry, medium- stiff to stiff silty clay and sandy clay.

ARTIFICIAL FILL

Artificial fill is present along and upslope of a ridge that crosses the proposed development area. The fill generally consists of clay soils that likely were removed from the area to the east during previous grading or quarry activities.

LANDSLIDE DEPOSITS

A landslide was identified in the vicinity of the south corner of the proposed development area, as shown on the Site Plan, Plate 2. Mitigation of the landslide and its potential impact on development of the site are discussed below.

FAULTING

Approximately one-half of the property is located within a State of California Earthquake Fault Hazard Zone (CGS, 1982) for the Hayward fault. The southwest limit of the Earthquake Fault Hazard Zone as it crosses the site is shown on the Site Plan, Plate 2. The main trace of the Hayward fault is mapped crossing the site near the property’s eastern property line (California Geological Survey, CGS, 1982; Graymer, 1995; Crane, 1988; Dibblee, 1980; Radbruch-Hall, 1974; Herd, 1978; Lienkaemper, 2006). The area proposed for development is not within the state designated Fault Hazard Zone. However, previous geologic investigations at the site and surrounding properties (BSA, Engeo, Makdissy, Soil Engineering Consultants, Earth System Consultants, Judd Hull) indicate the presence of fault traces south of the hazard zone (Site Plan). Fault traces located within exploration trenches and those inferred by site reconnaissance and aerial photograph interpretation were mapped by those consultants, with revisions or updates made as subsequent investigations were completed. The most recent work was completed by BSA in April 2017. Based on that work, BSA mapped traces of two splay faults crossing the southwestern portion of the site. We recommended setbacks from the faults with a “Development Zone,” located between the setback limits. The setback limits are shown on the Site Plan, Plate 2.

SITE INVESTIGATION

FIELD EXPLORATION

BSA conducted two supplemental fault ground-rupture potential investigations of the site. Field exploration during those investigations, conducted in December 2016 (BSA, 2017a) and March 2017 (BSA, 2017b), included excavation of 12 exploratory trenches with depths of excavation that were generally between 5 and 7 feet below the ground surface (bgs) and locally as deep as 17-½ feet. The excavations for the exploratory trenches were completed using a Caterpillar 312 excavator with a three-foot bucket.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 5

Five test pits were excavated for this geotechnical investigation following completion of the second set of six exploratory trenches excavated for the fault investigation in March 2017. The excavations for the test pits were completed using a Caterpillar 312 excavator with a three-foot bucket.

Five borings were drilled on March 21, 2017, by Pitcher Drilling using a track-mounted drill rig with hollow-stem augers. Borings were extended to depths of between 11-½ and 31-½ feet bgs. Soil sampling and penetration resistance testing were performed in the borings beginning just below the surface and at intervals of approximately 5 feet to the maximum depth of exploration. In addition, two shallow hand-augered borings were advanced to log surficial soil deposits. A member of our staff visually classified the soils in the field as the drilling progressed and recorded a log of each boring. Sampling was conducted using either a 2½-inch inside diameter Modified California sampler with 6-inch long liners or a 2-inch outside diameter, 1⅜-inch inside diameter Standard Penetration Test (SPT) split-spoon sampler (smooth inside bore with no provisions for use of liners). The samplers were driven 18 inches with a 140-pound hammer falling 30 inches. The number of blows required to drive the sampler the last 12 inches of the 18-inch drive are shown as blows per foot on the boring logs. Soil samples from the borings were transported to our laboratory for further examination and testing.

The logs of the borings, which are based on field classifications as as the results of laboratory tests, are presented in Appendix A along with a key for the classification of the soil. Visual classification of the soils was made in general accordance with the Unified System (ASTM D2487). The test pit and exploratory trench logs are presented in Appendix B. The boring, test pit and trench logs depict subsurface conditions at the locations explored at the time of exploration. Subsurface conditions may vary with the passage of time due to changes in groundwater levels or other factors. Some variations in subsurface conditions should be expected between points of exploration. The locations of the borings, test pits and exploratory trenches are shown on the attached Site Plan, Plate 2. The boring locations plotted were determined based on readings obtained using a hand-held GPS device (accuracy ± about 10 feet). The locations of the exploratory trenches and test pits excavated by BSA were determined by survey conducted by Wood Rodgers, Inc. The locations of trenches excavated for fault investigations conducted by others are considered to be approximate.

GEOTECHNICAL LABORATORY TESTING

Soil samples from the borings were transported to our laboratory for testing. Laboratory tests were performed on selected soil samples to evaluate their physical characteristics and engineering properties. Laboratory testing included moisture, density, , grain size analyses, unconfined compressive strength and triaxial compression tests performed on selected samples. Laboratory test results are presented in Appendix D with some of the results also included on the boring logs.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 6

SUBSURFACE CONDITIONS

Soils

The property has been extensively modified by grading or quarrying in the central area of the property, which extends into the northeastern portion of the development site. This previous activity resulted in artificial fills overlying the mapped geologic deposits. The fill soils range in depth from about 1 to 3 feet below the existing surfaces. Fill soils are also present at test pit and trench locations with fill ranging from about 5 feet to as much as 18 feet in depth. Refer to the trench logs for additional information regarding fill depths. These soils are uncompacted.

The surficial soils covering the site consist of residual soils derived from weathering of the bedrock deposits at the site and the hillside to the east. The soils are predominately moderately to highly expansive clays with varying amounts of and some . The soils are medium stiff in the upper few feet and increase in stiffness below. More detailed subsurface information is contained in the boring logs in Appendix A and the trench logs in Appendix B.

Bedrock

The materials below the residual soils consist of highly to completely weathered bedrock materials that present as soils within the depths of excavation at the trenches. Less weathered bedrock consisting of clayey siltstone was encountered in Boring B-2 at a depth of 24 feet bgs. The siltstone is friable, highly fractured to crushed and partially decomposed. A layer of gravelly sand was encountered at a depth of 23-½ feet in Boring B-6. The sand is dense. Below the gravelly sand we encountered bedrock consistent with highly weathered clay shale. The material was noted to be friable and crushed.

Groundwater

During the course of development of the La Vista project (at the site of the former La Vista quarry) which is located immediately upslope of the subject project site, BSA personnel observed several springs in the vicinity of quarry cut slopes as excavations were made to grade the site and in the construction of Tennyson Road adjacent to this project. An extensive array network of subdrains was installed. Recent observations of the subdrain outfalls revealed steady flows, confirming that shallow groundwater is present in the area upslope of the subject site. Groundwater seepage was observed at exploratory trenches T-7, T-9 and T-10 in the northeastern area of the proposed development, northeast of the aforementioned ridge. The water level stabilized at a depth of about 4 feet below the ground surface (bgs) over night.

The borings were monitored for visible signs of free groundwater during and immediately after completion of drilling each boring. Groundwater was encountered in one boring, Boring B-6, at a depth of 24 feet bgs. Groundwater was not evident in the other borings.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 7 The depth to groundwater can be expected to fluctuate both seasonally and from year to year. Fluctuations in the groundwater level may occur due to variations in precipitation, irrigation practices at the site and surrounding areas, climatic conditions, pumping from and other factors not evident at the time of our investigation.

GEOLOGIC AND SEISMIC HAZARDS

The Alquist-Priolo Earthquake Fault Zoning (formerly Special Studies Zone) Act (AP Act) was signed into California law on December 22, 1972. The intent of the AP Act is to mitigate the hazard of surface faulting ground-rupture to structures for human occupancy by prohibiting the siting of most structures for human occupancy across traces of active faults. The Mapping Act (SHMA) was enacted by the California legislature in 1990. The purpose of the SHMA is to minimize loss of life and property through the identification, evaluation and mitigation of seismic hazards, specifically the hazards of liquefaction, or earthquake-induced land sliding. These Acts require the California State Geologist and the Department of Conservation, California Geological Survey to identify and map areas prone to earthquake- induced ground failures and "Zones of Required Investigation" to reduce the threat to public health and safety and to minimize the loss of life and property posed by earthquake-induced ground failures.

FAULT RUPTURE

The potential for ground-rupture to occur with activity on a fault is one of the hazards associated with faulting. Seismic shaking is also a fault-related hazard, as discussed below. As discussed above, extensive investigation of the site has been conducted to evaluate the potential for fault ground-rupture on the site. In keeping with the California Code of Regulations and the subsurface exploration findings of our previously completed fault ground-rupture investigations, BSA recommended a fault ground-rupture setback from the splay fault found in our exploratory trenches. Given the maturity of the shear zone at the Hayward fault, the corresponding low probability that ground rupture will occur at locations not previously ruptured, the secondary nature of the splay faults exposed in our trenches, and the direct method of fault location, it is our opinion that the potential for ground-rupture to occur within the development zone shown on the Site Plan, Plate 2 is low.

SEISMIC SHAKING AND SEISMIC DESIGN PARAMETERS

The site is located in a region of high seismicity. There are several major faults within the greater San Francisco Bay Area that are capable of causing significant ground shaking at the site. The most notable of these are the Hayward, Calaveras and San Andreas faults. The site will likely be subject to at least one moderate to severe earthquake and associated seismic shaking

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 8 during the useful life of the planned development, as well as periodic slight to moderate . The probability of one or more earthquakes of magnitude 6.7 (Richter scale) or higher occurring in the San Francisco Bay Area is evaluated by the Working Group on California Earthquake Probabilities on a periodic basis, as are the probabilities of earthquakes of varying magnitudes on each of the major faults. The faults with the greater probability of a moment magnitude of 6.7 or higher earthquake between 2014 and 2044 are the Hayward fault at 14.3 percent, the Calaveras fault at 7.4 percent and the San Andreas fault at 6.4 percent. Some degree of structural damage due to strong seismic shaking should be expected at the site, but the risk can be reduced through adherence to seismic design codes.

We are providing the following 2016 California Building Code seismic design criteria from the U.S. Geological Survey Earthquake Hazards Program U.S. Seismic Design Maps application. Seismic design parameters were obtained from the U.S. Seismic Design Maps, determined with consideration of the 2010 ASCE 7-10 (w/March 2013 errata) publication, site location of latitude: 37.6355 N and longitude: 122.0500 W, site soil classification C, and risk category I/II/III.

Site Coefficients and Risk-Targeted Maximum Considered Earthquake Spectral Response Acceleration Parameters Site Class D

Mapped Spectral Acceleration for Short Periods, Ss 2.442 g Mapped Spectral Acceleration for 1-Second Period, S1 1.016 g Site Coefficient Fa 1.0 Site Coefficient Fv 1.5 Acceleration Parameter SMS 2.442g Acceleration Parameter, SM1 1.524 g Acceleration Parameter, SDS 1.628 g Acceleration Parameter, SD1 1.016 g Long-Period Transition Period, TL 8 seconds Seismic Design Category D

Additional Parameters for Sites with Site Design Categories D through F Peak Ground Acceleration, PGA 0.943 Site Coefficient, FPGA 1.0

Peak Ground Acceleration – geometric mean, PGAM 0.943 Risk Coefficient at 0.2 s Spectral Response Period, CRS 0.981 Risk Coefficient at 1.0 s Spectral Response Period, CR1 0.957

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 9

EARTHQUAKE-INDUCED LANDSLIDE POTENTIAL

The site is not located within the zone of required investigation for potential ground displacement triggered by an earthquake as identified by the California Geologic Survey on the State of California Seismic Hazard Zones map for the Hayward Quadrangle, issued 2003. Review of the Landslide Hazard Identification Map No. 37 (DMG 1996) indicates that the area is unmapped due to extensive grading activities. Mapping by Wentworth et. al. (USGS 1997) shows the site in an area with few if any landslides. More specifically, the mapped zone is described as “Few Landslides - contains few, if any, large mapped landslides, but locally contains scattered small landslides and questionably identified larger landslides; defined in most of the region by excluding groups of mapped landslides but defined directly in areas containing the 'Many Landslides' unit by drawing envelopes around areas free of mapped landslides. As discussed below, we did map one small landslide above a drainage along the southeast property line. We also conducted slope stability analyses to assess the stability of natural and graded slopes.

LIQUEFACTION POTENTIAL

The site is not located within the zone of required investigation for liquefaction potential as identified by the California Geologic Survey on the State of California Seismic Hazard Zones map for the Hayward Quadrangle, issued 2003.

CONCLUSIONS AND RECOMMENDATIONS

GENERAL

Based on the information collected during this investigation and prior investigations, it is our opinion that development of the site is feasible from a Geotechnical Engineering perspective, provided that the recommendations contained in this report are incorporated into the design and construction of the project. The primary geotechnical concerns with the site are:

 Stability of natural, and proposed cut and fill slopes.  Expansive near-surface soils.  Existing uncompacted fill at exploratory excavations and associated with past grading activities.  Shallow groundwater conditions requiring subsurface drainage.

Our detailed design and construction recommendations pertaining to site clearing and preparation, site earthwork, foundations, retaining walls, concrete slabs-on-grade (flatwork) and pavements are presented below.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 10

SITE DESIGN CONSIDERATIONS Building Setbacks from Slopes

Residential structures should be setback from top slopes a minimum of 10 feet. Residential structures should be setback from toe slopes a minimum of 10 feet.

Surface Drainage

The area to the east of the proposed development, which will remain as undeveloped open-space, drains toward the proposed development. A drainage ditch should be constructed slightly upslope of the planned cut slope along the northeast side of the proposed development.

Surface water should not be allowed to collect on or adjacent to structures or pavements anywhere on the site during or after construction. Final site grading should provide surface drainage away from structures, pavements and slabs-on-grade to reduce the percolation of water into the underlying soils. Surface drainage on residential lots should comply with Section 1804, Subsection 1804.3 of the California Building Code. If recommended surface gradients cannot be met or where there are landscape areas around the structures that cannot drain freely through sheet flow, area drains should be considered. Even with the recommended gradients there is a potential that ponding conditions may develop adjacent to the buildings over time. Where positive drainage around buildings cannot be established and maintained as part of the site grading and paving design, area drains should be provided around the structures in landscape and possibly within the areas of concrete flatwork where it abuts the structures.

Surface drainage should be directed away from the top of cut and fill slopes by sloping the ground surface at least 2 percent.

Rainwater collected on the roofs of the buildings should be transported through gutters, downspouts and closed pipes, which discharge away from the buildings and preferably into the storm water management system such as the bioretention facilities. Roof runoff should not be allowed to drain into landscape area in close proximity to the perimeter of the buildings.

Pavement areas should be sloped and drainage gradients maintained to carry surface water off the site. Ideally all pavements will be designed with a crown to allow for drainage toward the pavement perimeter. A cross slope of 2 percent is recommended in asphalt concrete pavement areas to provide surface drainage and to reduce the potential for water to penetrate into the pavement structure. Recommendations for control of seepage water entering pavement structures and pavement section drainage are presented in the Structural Pavements section of this report.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 11 Subsurface Drainage

During our field investigation, groundwater was encountered as shallow as 4 feet below the ground surface in the north and northeast areas of the of the planned development area, in the vicinity of the proposed road and cut slope. This relatively shallow groundwater could adversely affect future cut slope stability and pavement in addition to creating a surface water nuisance. We recommend a deep subdrain be installed along the northeastern and northern bounds of the proposed development. The subdrain should begin at the east end of the site at the top of the ridge above the cut slope, continue northwesterly along the top of the cut slope and then continue along the roadway to the west end of the site where the road crosses the wetland area. The subdrain should be installed to a depth of 10 feet along the northeastern side of the project, with the depth of installation reduced to 5 feet below the ground surface along the northern bound of the development.

Additional subsurface drains are recommended where fill slopes and retaining walls will be constructed as discussed in more detail below. Site conditions, particularly at cut slopes along the northern and northeastern bounds of the development area should be monitored for indications of groundwater seepage by a representative of the Geotechnical Engineer. If seepage appears at cut slopes or excavations for underground utilities, additional subdrains will be required.

Bioretention Areas

Bioretention swales and basins should be located at least 5 feet away from foundations, roadways, and exterior concrete flatwork. Bioretention swales and basins in close proximity to foundations have the potential to undermine the foundation or cause a reduction in the soil . Bioretention swales and basins located in close proximity to roadways and exterior concrete flatwork can cause settlement of these structures as well as cracking associated with lateral extension of these structures with lateral movement of the supporting soils. Where a 5-foot separation is not practical or possible due to site constraints, bioretention areas located within 5 feet of foundations, pavements or concrete flatwork should be constructed with structural side walls capable of withstanding the loads from the adjacent improvements. In the case of a building foundation in close proximity to a bioretention area, a deepened foundation edge designed as a retaining structure may be an option. Precast units may be an expedient method of installing bioretention facilities that are capable of supporting concrete flat work, roadways and foundations.

Bioretention basins or swales should not be constructed in proximity to the top of a descending slope unless the basin or swale is fully lined to preclude stormwater into the site above the slope. Bioretention areas located within 5 feet of building foundations or pavements should also be lined with impermeable liners. A perforated drain pipe should be provided within the swale or basin when a liner is installed or where the site soils have a low permeability rate

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 12 and infiltration capacity (i.e. the clay soils at the subject site). The perforated pipe should lead to a solid-wall pipe to convey accumulated water to a suitable point of discharge.

SLOPE STABILITY

Slope stability analyses were performed to evaluate the stability of the existing hillside slope below the proposed development with a 15-foot high fill slope at the southwest side of the site and a 20-foot high cut slope between the lower and upper terraces. The fill and cut slopes were models at inclinations of 2 ½-H:1V. The slope profile is shown on Plates 8 and 9. Our slope stability analyses were performed using the program Slope/W. Analyses were performed using models based on Morgenstern-Price and Bishop methods of slices for circular shaped failure surfaces. The slip circle calculated to have the lowest factor of safety against failure is referred to as the critical failure surface.

Soil strength parameters were developed based on the soils exposed in our borings and trenches, the results of geotechnical laboratory testing on samples collected during this investigation as well as the results of geotechnical laboratory testing during our previous investigations of the former La Vista Quarry site surrounding the subject site, and engineering judgement. The soil parameters used in the analyses are shown on Plates 8 and 9.

Static Slope Stability

For the analysis of static slope stability, we utilized static strength parameters and programmed the stability program to search for the critical failure surface. We analyzed a 15-foot high fill slope at an inclination of 2 ½-H:1V above a natural slope at 3H:1V and a 20-foot high cut slope. Based on this search, the program determined that the most critical failure surface initiates behind the top of slope and propagates down through the upper bedrock unit that presents as soil due to it crushed and highly weathered state, and the less weathered bedrock to a depth of about 60 feet. The critical failure surface for this analysis had a factor of safety 3.1 for the fill slope and natural slope below, which indicates that the slope should be stable.

Pseudo-Static Slope Stability

The pseudo-static slope stability analysis involves applying a horizontal acceleration coefficient to the static slope stability model to evaluate the slope for dynamic stability during an earthquake. We performed the pseudo-static slope stability analyses in general accordance with guidelines provided in the California Geological Survey’s SP 117A (2008). A seismic coefficient (k) of 0.49 was used to evaluate slope stability under seismic shaking conditions. This coefficient was determined using the simplified methods of Blake et al. (2002), a PGA of 0.94g, a Magnitude of 6.8, a distance of less than 10 km and a threshold displacement of 5 centimeters. For this analysis, the critical failure surface was a circular failure that initiated at the top of the levee, propagated down through the levee fill and below the levee to the top of the underlying sand layer and terminated in the middle of the channel. The calculated factor of BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 13 safety for this critical failure is 1.04, which indicates that instability resulting in displacement greater than 5 cm at the top of slope should not occur during this event.

GRADED SLOPES Cut Slopes

We recommend that cut slopes generally be constructed at slope gradients no steeper than 3H:1V, except for cut slopes less than about 10 feet in height which should be no steeper than 2- ½H:1V. We recommend that all cut slope exposures be carefully examined by an engineering geologist for evidence of potential instability. Cut slopes are not anticipated to exceed a height of 25 feet. Mid-slope benches are not required for slopes less than 30 feet high.

Due to variations in the geologic deposits across the site and in the immediate vicinity of the site we recommend that all cut slopes should be observed by an engineering geologist during grading for evidence of potential instability. Where adverse bedrock structure or zones of geologic weakness are encountered in cut slopes during grading, remedial measures such as flattening the slope or slope reconstruction may need to be performed. If very highly expansive claystone bedrock or cohesionless sandstone bedrock is exposed in the cut slope, these areas may need to be reconstructed with a buttress constructed using suitable engineered fill material. The project Geotechnical Engineer should develop specific remedial alternatives as cut slope conditions are exposed during grading. We also recommend that an engineering geologist perform annual reviews of the cut slopes after development.

Based on the data obtained, there are no specific zones of bedrock we now recommend for remedial treatment. However, this may be a limitation of the data. It would be prudent to expect some remedial slope buttressing could be needed following inspection of the actual exposed cut slopes.

Surface drainage should be installed up slope of cut slopes to intercept surface runoff. Runoff should be collected in a concrete lined v-ditch and should be conveyed to a suitable point of discharge.

Fill Slopes

The stability of planned fill slopes depends on proper placement and construction of keyways and benching, subsurface drainage, fill compaction and slope gradients. We recommend that fill slopes with a height of 15 feet or greater be constructed at slope gradients no steeper than 3H:1V. Slopes up to a height of 15 feet may be constructed at a maximum gradient of 2-½H:1V. If used for fill slope construction, residual soils and landslide debris should be properly blended with bedrock materials. In general, blending should consist of one part weak soils to three parts minimum bedrock materials.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 14 Fill slopes are not anticipated to exceed a height of 25 feet. Mid-slope benches are not required for slopes less than 25 feet high. In the event that 25 feet or greater in height is planned, a drainage ditch should be constructed on a bench placed at mid-slope. Benches should be at least 8 feet wide with a concrete-lined V ditch to conduct runoff.

Fill slopes should have a 20-foot wide geogrid reinforced keyway. Wider keyways may be required as determined in the field by the Geotechnical Engineer. Keyways should extend a minimum of 8 feet below the existing ground surface (as measured at the downslope side of the keyway) into the bedrock or firm soil, and slope down and back into the hillside at a 5 percent gradient. The final depth of keyways should be determined by the Geotechnical Engineer in the field during grading. Five layers of geogrid reinforcement (Tensar TX-7, or a similar approved equivalent), extending across the full width of the keyway, with the first layer at the bottom of the keyway, and then 2-foot vertical spacing thereafter is recommended. Engineered fill is to be composed of cut bedrock materials. Plate 3, Fill Slope and Keyway Detail, contains a schematic of typical fill slope construction.

The keyway should contain a subdrain, and intermediate subdrains should be placed on benches where appropriate, as determined by the Geotechnical Engineer in the field during grading. Benches should be constructed into the hillside, approximately one equipment width, as the fill is being placed. The benches should slope slightly down and back into the hillside and should be constructed below the recommended depth of residual soil removal. Plate 3, Fill Slope and Keyway Detail, contains a schematic of typical bench construction. Subdrain pipes should typically be at least 6 inches in diameter at the back of the keyway, with 4-inch diameter pipes for drains on intermediate benches. Subdrains should be surrounded by and be underlain by at least 6 inches of Class 2 Permeable Material, as defined in Section 68-2.02F(3). The subdrain can daylight below the fill slope to an appropriate outfall structure protected with cobble and boulder sized rip rap.

Subdrains should consist of PVC perforated pipe conforming to ASTM Designation 03034, Type SDR 35 for fill depths less than 30 feet. Perforations should be placed facing down. Subdrains should typically be at least 6 inches in diameter. Subdrain laterals less than 200 feet in length can be constructed using 4-inch diameter pipe. All subdrains should be surrounded by and be underlain by at least 6 inches of Class 2 ''Permeable Material," as defined in Section 68-2.02F(3) of the Caltrans Standard Specification (2015). Subdrain trenches should be at least 18 inches wide and at least 4 feet deep, unless otherwise recommended. Final trench configurations should be approved by the Geotechnical Engineer. Subdrain trenches should be capped with 2 feet of engineered fill or topsoil, depending upon the subdrain location. Typical subdrain details are presented on Plate 4. Subdrain systems should be discharged into observable storm drain structures (inlets, manholes, ditches) where possible. Elsewhere, subdrains may discharge to suitable open-space locations.

The grading contractor should survey the locations of all subdrains and submit the latitude, longitude, and elevations to the Civil and Geotechnical Engineers as grading progresses.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 15 Some areas of seepage may develop after grading and house construction are completed. Additional subdrains will likely be needed in these areas should seepage develop.

Erosion Protection

All cut and fill slopes should be planted with deep-rooted, fast growing grasses before the first winter to reduce erosion. On a preliminary basis, some irrigation of slopes could be performed; however, specific details regarding irrigation systems, locations and discharge should be reviewed by BSA.

REMEDIAL GRADING

Remedial grading activities will be required to prepare the site to receive fill and to provide proper support for fill slopes and for structures. The details of remedial grading should be developed and a Remedial Grading Plan should be prepared after the site and grading plans have been prepared. Subsurface drainage plans should be prepared in conjunction with the preparation of the Remedial Grading Plan. The Remedial Grading plan should address the following:

Residual Soil Removal

Remove the upper 4 feet of residual soil in fill areas and replace with engineered fill. Remove residual soil in at-grade and cut areas if present within 4 feet of finish grade and replace with engineered fill.

Uncontrolled Fill

Uncontrolled fill in the northeastern area of the site not removed during design cuts and residual soil removal should be removed and replaced with engineered fill.

Exploratory trenches and test pits excavated within the planned development area by BSA and Engeo were backfilled with loosely placed uncontrolled fill. As discussed under Site Preparation and Grading, uncontrolled fill should be removed and, if required to establish site design grades, may be replaced as engineered fill. The approximate locations of the trenches and test pits are shown on Plate 2. Logs for the exploratory excavation made by BSA are included in Appendix B. Trench logs for excavations performed by Engeo are included in Appendix C.

Differential Fill on Building Pads

Cut/fill transitions should not be present with building pads. In addition, differential fill thickness within building pads should be limited to 10 feet. Over-excavation in portions of the building pads may be required to comply with these recommendations.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 16

Landslide Repair

A landslide is present at the southern tip of the proposed development, in the location of a proposed fill slope. Repair of the landslide should be performed concurrent with grading for the fill slope. A keyway will be required in this area for support of the fill slope. Any landslide debris not entirely removed by the required grading for the keyway and fill slope should be removed and the area then reconstructed as the fill slope is constructed.

Foundation Decoupling Section

A double layer of plastic, to be placed 3 feet below pad grade, is recommended at the building locations. See “Foundation Decoupling” in the Building Foundations section below for additional details.

EXPANSIVE SOILS

The near-surface residual soils and underlying highly to completely weathered bedrock is moderately to highly expansive. Expansive soils shrink and swell with changes in moisture content, especially seasonally. During the summer months, expansive soils can dry out and desiccate, with shrinkage cracks extending several feet deep. During the winter months, expansive soils can absorb excessive moisture and swell. In order to mitigate for expansive soils, moisture conditioning and compaction of expansive soils will need to be controlled as discussed below under Site Preparation and Grading. Additionally, foundations for residential structures should be designed for expansive soil conditions. Presoaking of the building pad subgrades prior to concrete placement will also be required.

EXCAVATION CHARACTERISTICS

Exploratory excavations were completed using a Caterpillar 312 excavator with a three-foot bucket. Excavation depths were generally limited to about 8 feet but did extend as deep as about 18 feet at the north end of Trench T-11. The materials encountered were readily excavatable with the equipment in use. Bedrock consisting of clayey siltstone was logged at a depth of 24 feet in Boring B-2. The material is friable, highly fractured to crushed and partially decomposed into clayey silt. In general, we anticipate that the site will be excavatable using conventional equipment for mass grading.

FILL MATERIALS

The on-site soil is generally suitable for engineered fill, provided it is free of debris, significant vegetation, rocks greater than 6 inches in largest dimension and other deleterious matter. Use of on-site soils and import soil for fill or backfill within 5 feet of the back of retaining walls should

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 17 be limited to those soils with a Plasticity Index of 20 or less. In addition, clay soils should not be used as backfill at mechanically stabilized earth (MSE) walls. Granular soils are recommended for backfill at MSE walls, as discussed in the Retaining Walls section of this report.

SITE PREPARATION AND GRADING

1. The Geotechnical Engineer should be notified at least 48 hours prior to site clearing, grading and backfill operations. The procedure and methods of grading may then be discussed between the contractor and the Geotechnical Engineer. 2. Boulders present within the area to be graded will need to be removed and placed outside of the development area. 3. Vegetation within the area to be graded is predominately seasonal grasses with occasional brush. Surface vegetation present at the time of grading should be stripped down to the soil surface. Vegetation should not be tilled or ripped into the site as a way of disposal. Should dense roots be present in the upper few inches of the soil or where dense organic matter is present, the top soil will need to be stripped from the site and stockpiled for use in future landscape areas. Organic laden soils should not be placed in compacted fills. 4. Existing uncontrolled fill up to about 3 feet in depth was encountered at exploratory trenches and test pits excavated to the northeast of an existing ridge crossing the development area. Fill up to about 6 feet in depth was encountered where exploratory trenches crossed the ridge. Uncontrolled fills identified during grading operations that are not removed as part of the planned grading of the site will need to be removed. Determination of the quality, and full lateral and horizontal extent of the fill present on the site was beyond the scope of this investigation. Thus, monitoring of the site during clearing and grading operations will be required to see that the uncontrolled fills are removed. The existing fill soils should be cleared of any over-size material (cobbles greater than 6-inches and boulders), debris or deleterious materials as they are excavated so that the soils can be reused as engineered fill. 5. Exploratory excavations made for fault ground-rupture studies were backfilled with uncontrolled fill. The uncompacted fill should be re-excavated and then be replaced as engineered fill in accordance with the recommendations presented below. 6. Residual soils blanketing the site should be removed to a depth of 4 feet below existing grade. 7. Landslide debris not removed as a part of the design grading, including recommended excavations for residual soil removal, keyway constructing at fill slopes and site benching to receive fill, should be removed down to stiff undisturbed soils. 8. Following the clearing and stripping operations and removal of uncontrolled and poorly compacted fills, residual soil and landslide deposits, the exposed surface should be scarified to a depth of about 12 inches, moisture conditioned, and recompacted to provide

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 18 a surface ready to receive fill. If zones of soft or saturated soils are encountered, excavations may be required to remove those soils. This should be determined in the field by the Geotechnical Engineer. After the soil subgrades have been properly prepared, the areas may be raised to design grades by placement of engineered fill. 9. Fill and backfill should be placed in thin lifts (normally 8 to 12 inches in loose lift thickness depending on the compaction equipment), properly moisture conditioned, and compacted as recommended below. 10. In general, fill soils should be compacted to no less than 90 percent relative compaction at a moisture content not less than 3 percentage points (“3 percent”) above the optimum moisture content. Where fill depths exceed 20 feet, fills deeper than 20 feet below design grade should be compacted to no less than 92 percent at no less than 3 percent above optimum moisture content. Where fill within the upper 5 feet of the site will be comprised of moderately to highly soils (PI>20) compaction of clay soils in building pad and concrete flatwork areas should be between 85 and 90 percent relative compaction at a moisture content at least 5 percent over optimum moisture content. Where fill within the upper 5 feet of the site will be comprised of low plasticity fine- grained soils and granular soils, those soils should be compacted to at least 90 percent at a moisture content of at least 3 percent above the optimum moisture content. Where previously compacted building pads become disturbed, they should be reprocessed to meet the compaction and moisture requirements. These soils should be uniformly moisture conditioned to at least 5 percent above optimum moisture content and compacted prior to concrete placement. 11. Prior to subgrade preparation, utility trench backfill in the pavement areas should be properly placed and compacted. All pavement subgrades should be scarified to a depth of 12 inches below finished subgrade elevation, moisture conditioned to at least 2 percent above the optimum moisture content, and compacted to at least 95 percent relative compaction. Subgrade preparation should extend a minimum of 2 feet laterally behind the face of the curb. Compacted subgrade should be stable and non-yielding under the weight of a fully loaded 10-wheel water truck prior to placement of the aggregate base section. Areas deemed to be exhibiting signs of instability as assessed by the Geotechnical Engineer should be reworked and/or stabilized until a well-compacted non- yielding surface is achieved. Subgrade soils should be maintained in a moist and compacted condition until covered with the complete pavement section. 12. Aggregate base for roadways should conform to the requirements for ¾” Class 2 aggregate base in Sections 26 of the Caltrans 2010 Standard Specifications. The aggregate base should be placed in thin lifts in a manner to prevent segregation, uniformly moisture conditioned, and compacted to at least 95 percent relative compaction to provide a smooth, unyielding surface. ASTM test procedures should be used to assess the percent relative compaction of soils and aggregate base.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 19 13. Engineered fill is material that is properly moisture conditioned, placed and compacted in accordance with the recommendations presented herein, as observed and documented by a representative of the Geotechnical Engineer. 14. Earthwork observations and soil density test services should be carried out by a representative of the Geotechnical Engineer during site clearing, grading and backfill operations to assist the contractor in obtaining the required degree of compaction and proper moisture content and to allow for documentation that the project requirements have been met. Where the compaction and/or soil moisture content are outside the range required, additional compaction effort and/or adjustment of moisture content should be made until the specified compaction and moisture conditioning is achieved. 15. Relative compaction (“compaction”) refers to the in-place dry density of the soil or aggregate base expressed as a percentage of the maximum dry density for soils and aggregate base tested as determined in the laboratory. ASTM test methods should be used to evaluate the relative compaction of processed subgrade below general fills, completed subgrade and aggregate base. In-place dry densities and moisture contents of compacted soils should be determined in accordance with ASTM test method D6938 ("Test Methods for Density of Soil and Soil-Aggregate In-place by Nuclear Methods [Shallow Depth]"). Maximum dry density and optimum moisture content should be determined by ASTM D1557 laboratory compaction test procedure.

UTILITY TRENCHES Trenches Adjacent to Building Foundations

To maintain the desired support for foundations, utility trenches running parallel or near-parallel to building foundations should be located away from the foundation such that the base of the trench excavation is located above an imaginary plane having an inclination of 1 Horizontal to 1 Vertical (1H:1V), extending downward from the bottom edge of the foundation toward the trench location. Where trench locations are restricted and must be in close proximity to foundations, footings or slab edges located adjacent to utility trenches should be deepened during the design of the project as necessary so that their bearing surfaces are below an imaginary plane having an inclination of 1H:1V, extending upward from the bottom edge of the adjacent utility trench. As an option to the use of a deepened foundation, the trench can be backfilled with controlled low strength material, such as sand- slurry, unless the use of sand-cement slurry is prohibited by the City of Hayward or the utility company.

Excavation

All excavations should conform to applicable state and federal industrial safety requirements. Safety in and around utility trenches is the responsibility of the general and underground contractors. Where necessary, trench excavations should be shored in accordance with current CAL-OSHA requirements to ensure safety.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 20

The contractor is cautioned that shoring or sloping back of trench walls may be required in some areas even with trenching limited in depth to 4 to 5 feet based on our experience during exploratory trenching of the site. In general, trench sidewalls should be sloped no steeper than 1 Horizontal to 1 Vertical (1H:1V) in stiff to hard cohesive soil and no steeper than 1-½H:1V in granular soils. Where weaker soils are encountered in the upper 4 to 5 feet of the site or trenches will extend deeper than 5 feet, trench sidewalls should be sloped no steeper than 1H:1V in stiff to hard cohesive soil, no steeper than 1-½H:1V in moist granular soils and no steeper than 2H:1V in dry granular soils. Flatter trench slopes may be required if seepage is encountered during construction or if exposed soil conditions differ from those encountered in in our borings, trenches and test pits. Heavy construction equipment, building materials, excavated soil, and vehicular traffic should not be allowed within 5 feet of the top (edge) of the excavation.

Groundwater Considerations

As noted above, shallow groundwater was encountered in the northeastern area of the site, which appeared to be a perched water zone. At the time of this investigation, groundwater was with about 4-feet of the ground surface. Underground contractors should be prepared to dewater their trenches and may need to stabilize the base of their excavations. Should unstable conditions be encountered at the base of the trenches, BSA should be contacted to discuss stabilization options.

Backfill

Materials type and placement procedures for utility bedding, shading and backfill materials should meet local agency and/or other applicable utility providers’ requirements. In the absence of a specific agency or utility company requirement, utility lines should be bedded and shaded with open-graded crushed rock or well-graded sand and gravel to at least 6 inches over the top of the pipe. The bedding and shading material should conform to the pipe manufacturer’s requirements. Open-graded gravel should be densified prior to placing subsequent backfill materials; well-graded sand and gravel should be compacted to no less than 90 percent relative compaction prior to placing subsequent backfill materials. Where open-graded gravel is placed as bedding, shading or backfill, the gravel should be fully wrapped or encapsulated using non- woven filter fabric such as Mirafi 140N or equivalent.

From a geotechnical perspective, utility trench backfill above the bedding and shading materials (beginning 6 inches above the top of pipe) may consist of on-site soils with a PI of 20 or less, that have been processed to remove rock fragments over 3 inches in largest dimension, rubbish, vegetation and other undesirable substances. Backfill materials should be placed in level lifts about 4 to 12 inches in loose thickness, moisture conditioned and mechanically compacted. Lift thickness will be a function of the type of compaction equipment in use. Thinner lifts (4- to 6- inch lifts) will be required for manually operated equipment, such as wackers or vibratory plates, and thicker lifts possible where a sheepsfoot wheel is used on the stick of an excavator. Jetting should not be used for densification of backfill on this project.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 21

Trench backfill consisting of fine-grained soil (clays and ) should be moisture conditioned to between 3 and 5 percent above optimum and compacted to at least 90 percent relative compaction where the soil PI is 20 or less. Where sand is used as backfill, it should be moisture conditioned to slightly above the optimum moisture content and compacted to at least 93 percent relative compaction. Trenches in pavement areas should be capped with at least 12 inches of compacted, on-site soil similar to that of the adjoining subgrade. The upper 12 inches of trench backfill for trenches located in streets should be compacted to at least 92 percent for moderately expansive soils and to no less than 95 percent relative compaction for soil that have a low expansion potential. The expansion potential of backfill soils should be assessed by the Geotechnical Engineer during the construction process.

BUILDING PAD PRE-SOAK

The upper 12 to 18 inches (depending on the depth of drying that has occurred) of the subgrade soils should be pre-soaked to at least 5 percent above optimum moisture content prior to constructing foundations. The pre-soaked pads should not be allowed to dry out to less than the recommended moisture content before concrete is placed. Subgrade moisture should be checked by a BSA representative prior to concrete placement.

LANDSCAPING AND LANDSCAPE IRRIGATION

Fluctuations in near-surface soils’ moisture content due to seasonal changes and irrigation, as well as the effects of landscaping can have an adverse impact on the foundations. According to the Post-Tensioning Institute (PTI), “watering should be done in a uniform, systematic manner as equally as possible on all sides to maintain the soil moisture content consistently around the perimeter of the foundation.” Areas of soil that do not have ground cover may require more moisture as they are more susceptible to evaporation. Ponding or trapping of water in localized areas adjacent to the foundations can cause differential moisture levels in subsurface soils.

Tree roots have the potential for causing uplift and possible distress to concrete slabs-on-grade, including building foundation slabs-on-grade and pavement. If trees are to be planted around or in close proximity to the buildings, the selection of the types of trees to be planted and the construction details for building foundations and slabs, as well as for pavements should be based, at least in part, on the consideration of future damage due to the presence of trees.

Whenever possible, trees should be located out from the building perimeter at a distance equal to or greater than the anticipated radius of the canopy of a mature tree. This would place the trees out from the buildings such that the buildings would not be within the drip line and dense root zone of the tree. Where trees are to be planted close to buildings or pavements, tree wells with root barriers extending to a minimum depth of 3 feet should be considered. Trees in close

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 22 proximity to foundations will require more water in periods of extreme drought and in some cases a root injection system may be required to maintain moisture equilibrium to reduce the potential for the trees to impact the foundations. The project landscape architect should be consulted to determine if there are any low water demand trees that will work within the planned project to reduce the potential impacts of trees on foundations and pavement.

BUILDING FOUNDATIONS

With highly expansive soils and the potential for slight ground distortion resulting from proximal fault rupture and strong seismic shaking, we recommend the use of post-tensioned (PT) slab-on- grade foundations and “decoupling” of the foundations from the underlying soils. Post-tensioned slab-on-grade foundations should be structurally designed to resist or distribute the stresses that are anticipated to develop as the result of supporting soil movement. Movement may be associated with expansive soil volume change and seismic-induced ground movement. Foundations in all areas of the site should be capable of withstanding differential movement of 2½ inches of vertical displacement of the ground surface across the span of the structure.

Foundation Decoupling

To decouple the foundations from the effects of lateral ground distortion, foundations should be supported by engineered fill constructed over two layers of 15 mil sheet plastic. Projections for deepened sections in the foundation, such as those commonly associated with anchor bolts at holdowns for shear walls, or steps in the foundation, should not penetrate the doubled plastic sheets.

Based on our recent work on the La Vista site located upslope of the subject project site, working with the foundation designer, the grading contractor and the developer, we developed a decoupling detail that allowed for installation of the doubled plastic sheets as part of the grading operation. This eliminated the need to re-excavate the site to install the plastic sheeting below the lowest foundation projection into the building pad after rough grading had been completed. Plate 6, Foundation Decoupling Detail, shows the recommended method to decouple the post- tension concrete slab foundations (PT slabs) from the ground. A double layer of sheet plastic (15-mil minimum) should be placed at the bottom of engineered fill building pads, with the plastic placed on smooth, stable (non-yielding) continuous flat pads. The plastic sheeting should be at least 6 inches below the lowest protrusion below the bottom of the PT slabs. Absent specific foundation design requirements, we recommend that the plastic sheeting be installed at a depth of 3 feet below the bottom surface of the post-tensioned concrete slab-on-grade foundations if it is to be installed during rough grading. Ideally, the plastic should extend to the building perimeter or slightly beyond. In the absence of identified building footprints on each lot, the plastic sheeting should extend to the limits of the designated building envelopes. Prior to installing the plastic sheeting, the grading contractor should consult with the Civil Engineer to confirm that the pad grades shown on the rough grading plans were set with consideration of the

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 23 slab thickness and a 4-inch thick capillary break. We anticipate a minimum post-tension slab- on-grade thickness of 15-inches.

Post-Tensioned Slab-On-Grade Foundation Design Parameters

Moderate to highly expansive soils are present on the site. Post-tensioned foundations should be designed in accordance with the design provisions as presented in the document Design of Post- Tensioned Slabs-On-Ground, third edition, published by the Post-Tensioning Institute (PTI), with consideration of Addendums No. 1 and No. 2. PT concrete foundation design parameters based on expansive soil parameters as well as consideration of the potential ground movement associated with seismic-induced ground distortion.

Allowable Bearing Capacity (may be increased by 1/3 for seismic 1,500 psf and wind loads at the discretion of the Structural Engineer) Passive Equivalent Fluid Pressure (neglect the upper foot if the 300 pcf ground surface is not confined by slabs or pavement) Base Coefficient 0.30 Edge Moisture Variation Distance Center Lift 8.0 feet Edge Lift 4.1 feet Differential Swell Center Lift 2.48 inches Edge Lift 3.97 inches Slab Minimum Thickness (in) 15 inches

Additional Design and Construction Considerations

Perimeter columns located outside of the main structure, such as those required for covered terraces or second floor areas projecting out beyond the building footprint should not be founded on spread footings that are structurally separated from the PT slab-on-grade foundation. Perimeter columns should be supported by the PT slab-on-grade foundation.

Even where increased stiffness is provided at the foundation level, some distortion may occur in the structures with bending of the slabs. This will need to be considered by the Structural Engineer. The above recommendations may not prevent all damage to the proposed residential development in the event of a major earthquake resulting in ground distortion and strong to violent shaking of the structures. Adherence to the above recommendations and the current building code during design and construction of the development should reduce such potential damage. The recommendations are not intended to be a guarantee that significant structural damage will not occur in the event of a maximum magnitude earthquake; the intent is to provide design input for use in design of a foundation that will not undergo catastrophic failure leading to structural collapse or cause loss of life in a major earthquake.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 24

MOISTURE VAPOR TRANSMISSION THROUGH INTERIOR SLABS-ON-GRADE

A vapor retarder should be installed immediately below the concrete in accordance with Section 1907 of the California Building Code. Sand should not be placed over the vapor retarder. Guidelines for capillary break installation and for installation of the vapor retarder are provided in ASTM E1745. A standard specification for the vapor retarder material is presented in ASTM E1643. The details of the materials and installation of a vapor retarder and capillary break should be determined by the project designers. A minimum 4-inch section of gravel is suggested for the capillary break.

RETAINING WALLS

Retaining walls can be of conventional cantilever or gravity type walls, or mechanically stabilized earth (MSE) retaining walls with geogrid. Conventional retaining walls can be supported on shallow foundations where the area in front of the wall is relatively flat and level. If walls are to be constructed above slopes, deep foundations, such as drilled, cast-in-place concrete piers may be required. Where retaining walls are free to rotate at least 0.1 percent of the wall height at the top of the backfill, as with a cantilever wall, the walls may be designed using an active . Walls that are incapable of this deflection or walls that are fully constrained against deflection, should be designed for an equivalent fluid at-rest pressure. Retaining wall and wall foundation design parameters are presented below.

Conventional Concrete or Concrete Masonry Retaining Wall

Retaining Wall Design Parameters Active Equivalent Fluid Pressure * Level backfill (drained conditions) 55 pcf Sloping backfill 3H:1V (drained conditions) 65 pcf Sloping backfill 2H:1V (drained conditions) 75 pcf At-Rest Equivalent Fluid Pressure (Level backfill and drained 90 pcf conditions) Seismic Load for retained height (H) of 6 feet or greater 32H2 Line Load applied at 0.33H above the wall base Designated by Surcharge Load, where applicable Structural Engineer * Values listed are applicable for backfill or retained soils within a distance H from the back of wall having a Plasticity Index of 20 or less. High Plasticity soils should not be used as backfill.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 25 Retaining Wall Shallow Foundation Recommendations Allowable Bearing Capacity (may be increased by 1/3 for temporary seismic and wind loads at the 2,000 psf discretion of the Structural Engineer) Allowable Passive Equivalent Fluid Pressure 250 pcf Level ground surface in front of the wall Ignore the upper 2’ of embedment Sloping surface in front of the wall. Ignore the upper 3’ of embedment Allowable Base Friction Coefficient 0.30 24 inches below lowest adjacent Minimum Footing Depth grade * * Where footings are constructed in proximity to descending slopes, the base of the footing should be at a depth sufficient to provide a minimum of 10 feet of soil in front of the base of the at the base of the footing as measured laterally out to the face of the slope.

Drilled cast-in-place concrete pier foundations designed to resist both lateral and vertical loads can be used to retaining walls located above descending slopes.

Drilled Cast-In-Place Pier Foundation Design Parameters Allowable Skin Friction – Vertically Down 400 psf (may be increased by 1/3 for seismic and wind loads; neglect the upper 2 feet in calculating pier capacity) Allowable Skin Friction – Uplift 250 psf (may be increased by 1/3 for seismic and wind loads; neglect the upper 4 feet in calculating pier capacity) Passive Equivalent Fluid Pressure, acting on 1.5 pier 350 pcf diameters (neglect the upper 4 feet in calculating the lateral capacity) Minimum Pier Spacing (center to center) At least 3 pier diameters apart

The piers should be drilled and poured on the same day. If the drilled pier holes are to be left open overnight for production purposes, the drilled pier holes should be covered; however, the potential for caving increases with time. Groundwater may seep into the pier holes. The contractor should be prepared to case the drilled holes. Any water that accumulates in the holes should be removed prior to concrete placement.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 26

Mechanically Stabilized Earth Retaining Wall

MSE Retaining Wall Preliminary Design Considerations Backfill Soil Soil Friction Angle (soil classified as SM, SC, SP, GM, GC) 30° Unit Weight (Wet) (soil classified as SM, SC, SP) 125 pcf Unit Weight (Wet) (soil classified as GM, GC) 140 pcf Maximum fines content (passing #200 sieve) 20% Retained Soil Soil Friction Angle (soil classified as CL, CH, SC) 16° Soil (soil classified as CL, CH, SC) 700 psf Unit Weight (Wet) (soil classified as CL, CH, SC) 125 pcf Allowable Base Friction Coefficient 0.25 Allowable Bearing Capacity (may be increased by one-third for temporary seismic and wind loads at the discretion of the Structural Engineer). 2,000 psf Minimum Embedment 16 inches below lowest adjacent grade* * The base of MSE walls should be setback from descending slopes. This may require the construction of a bench on an existing slope with the bench extending 10 feet out from the base of the wall.

MSE wall design responsibility is commonly assigned to the MSE wall installer or the MSE wall supplier, under subcontract to the general contractor. Design of MSE walls requires specific information including allowable soil bearing capacities, soil strength parameters (phi angle and cohesion) for the backfill in the reinforced zone as well as the retained soils beyond the reinforced soil zone, soil unit weights for specific soils in the reinforced zone and retained zone. The values presented are intended for preliminary design purposes only. The soil friction values are intended to be maximum values unless specific soils are specified for the reinforced soil zone and retained soil zone immediate behind the reinforced soil zone. Additional information required for design is the intended soil reinforcement, height of the wall, backfill condition (level or sloping), and preload loads. The design must consider sliding, overturning and both internal and global stability. Global stability is often overlooked; global instability is a common cause of MSE wall distress or failure. A factor of safety of no less than 1.3 should be considered for global stability.

We should review the MSE wall design, plans and specifications to confirm that: appropriate input values were used in the design; stability (both global and internal) requirements are met; complete materials specifications are provided for the wall facing, soil reinforcement (geogrid), wall drainage, backfill soils at the reinforced soil zone including minimum soil friction angle and soil unit weight.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 27 Wall Surcharge

The above recommended lateral pressures do not include any surcharge loads due to loads or structures placed above the wall. The surcharge effect from loads adjacent to the walls should be included in the wall design. The surcharge load for restrained walls should be based on one-half of the applied load above the wall distributed over the full height of the wall. The surcharge load for walls free to deflect should be based on one-third of the applied load above the wall distributed over the full height of the wall.

To prevent excess lateral forces from being applied to the retaining wall, heavy compaction equipment (such as loaders, dozers, or sheepsfoot rollers) should not be allowed within a horizontal distance of about 5 feet behind the top of the retaining wall. The backfill directly behind the retaining wall should be compacted using light-weight equipment such as self- propelled vibrating rollers or hand operated equipment (jumping jack compactors or vibratory plates). For backfill of the retaining wall using self-propelled vibrating rollers, an additional uniform lateral pressure of 200 psf should be added over the entire height of the retaining wall.

Retaining Wall Backdrains

The above recommended lateral pressures are based on drained conditions. All walls retaining more than 2 feet of soil should be provided with a backdrain to prevent hydrostatic pressure build-up. The backdrain should consist of a subdrain pipe placed at the base of the wall with a vertical drain constructed or installed behind the retaining wall. Subdrain pipes should be SDR 35 perforated pipe, typically at least 4 inches in diameter, installed with the perforations facing down. All subdrain pipes should be surrounded by and be underlain by at least 4 inches of Class 2 Permeable Material, as defined in Section 68-2.02F(3) of the State of Caltrans Standard Specification (2010). The vertical drain should extend from the Class 2 Permeable Material encapsulated subdrain pipe at the base of the wall to about 1 foot below the finished grade behind the retaining wall. The vertical drain should consist of Class 2 Permeable Material and should be at least 12 inches thick. Alternatively, a geo-composite drain, such as Miradrain 6200 or approved equivalent, may be used in lieu of the Class 2 Permeable Material vertical drainage blanket for walls other than MSE walls. The geo-composite should drain into the subdrain pipe as shown on Plate 7. The upper 1 foot of wall backfill above the backdrain should consist of compacted site soils. The subdrain pipe should tie into a solid pipe leading to a suitable gravity discharge or storm drain system.

Where slopes are located above retaining walls, surface water draining toward the wall should be collected in a lined concrete ditch located at the back of the wall. Surface water should not be allowed to percolate into the retaining wall backfill. The concrete ditch should direct the water into a closed pipe to be conveyed to a suitable discharge point.

Even with the presence of a wall drain, dampness may occur at the face of the walls. If this is objectionable, waterproofing of the walls should be considered.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 28

Retaining Wall Backfill

Backfill soils for concrete or masonry walls should have a PI of 20 or less for soil placed within the lateral distance equal to the height of the wall.

Backfill soils at the reinforced soil zone behind MSE walls should be primarily granular with a maximum fines content (passing the #200 sieve) of 20 percent and a minimum friction angle of 34 degrees. Backfill should be compacted as discussed in the section “Site Preparation and Grading,” above.

Laboratory testing of backfill soils should be performed prior to and during backfilling operations to confirm that the soil friction angle requirement for soils used as backfill in the reinforced soil zone is met and to confirm soil unit weights are within the specified range.

Backfill should be compacted to not less than 90 percent relative compaction. Over-compaction should be avoided because increased compactive effort can result in lateral pressures significantly higher than those recommended above. To prevent excess lateral forces from being applied to the retaining wall, heavy compaction equipment (such as loaders, dozers, or sheepsfoot rollers) should not be allowed within a horizontal distance of about 4 feet behind the top of the retaining wall. The backfill directly behind the retaining wall should be compacted using light-weight equipment such as self-propelled vibrating rollers or hand-operated equipment (jumping jack compactors or vibratory plates). Backfill should be placed and compacted according to the requirements for engineered fill contained in the “Site Preparation and Grading” section.

CONCRETE FLATWORK

With the exception of slabs subject to vehicular loads, it is our opinion that, from a Geotechnical Engineering standpoint, exterior concrete slabs-on-grade, such as sidewalks and patios, can be placed directly on the prepared subgrade. The use of aggregate base as support for concrete flatwork should be avoided except in traffic areas where required as part of a structural section, or where required for compliance with a City standard.

Exterior concrete flatwork such as sidewalks, walkways and driveways will be subject to differential soil movements due to the expansive soils. A minimum slab thickness of 5 inches and reinforcing steel should be considered for improved slab performance. Steel reinforcement ( as opposed to wire mesh) should also be considered to reduce cracking and the potential for tripping hazards to develop between adjacent concrete panels due to expansive soil movement and/or tree roots. Minimum recommended reinforcement is No. 4 steel reinforcing bars at 18 inches on-center each. The minimum recommended steel will not prevent the development of slab cracks but will aid in keeping the construction joints relatively tight and in reducing the potential for differential movement between adjacent panels.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 29

In addition to steel reinforcement, frequent construction or crack control (contraction) joints should be provided in all concrete slabs where cracking is objectionable. Deep, scored joints spaced no more than 6 feet apart should be considered to control shrinkage cracking. Scoring of contraction joints should extend slightly deeper than one-quarter the slab thickness to be effective.

Where exterior concrete slabs-on-grade are planned, we generally recommended that exterior slabs-on-grade (i.e. sidewalks) be cast free from adjacent footings or other edge restraint. Using a strip of ½-inch thick asphalt impregnated felt or other commercially available expansion joint material between the slab edges and the adjacent structure may accomplish this. Where there is a concern that a trip hazard could develop due to differential movement between the exterior slab- on-grade and the adjoining foundation, or where concrete flatwork abuts embedded curbs, consideration may be given to tying the slab to the foundation or to the curb with reinforcing steel (rebar) dowels. Where the residential structures are to be constructed at a distance of 10 feet to 15 feet from the top of a descending slope, there is a potential for concrete flatwork constructed in the area between the building foundation and the top of slope to move laterally slightly over time due to the effects of expansive soils. Securing the flatwork by tying it to the foundation or other methods should be considered.

With the on-site clay soils having a moderate to high expansion potential, it is important that these soils be properly moisture conditioned during grading operations and that the moisture content is maintained until the concrete has been placed. The moisture content of the subgrade soils should be checked several days prior to the placement of concrete, or baserock where required, to allow for presoaking where needed. Where moderately to highly expansive soils are present and the soil moisture content is less than 5 percent above optimum, the subgrade should be presoaked to at least 5 percent over optimum moisture content prior to placing concrete. Even with proper site preparation there will be some effects of soil moisture change on concrete flatwork.

The above recommendations, including soil moisture conditioning, contraction joints and steel reinforcement are intended to help reduce the potential for distress in concrete flatwork, but may not totally eliminate distress.

STRUCTURAL PAVEMENT Flexible Pavement

The Caltrans flexible pavement design method was used to develop the recommended pavement sections presented below. Highly expansive soils are present in the upper several feet of the site. Soils with high expansion potential, as exhibited by a Plasticity Index (PI) in excess of 25 and with a high clay fraction and low sand or silt content typically have an R-value on the order of 5. The pavement section recommendations presented below are based on a subgrade R-value of 5.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 30

FLEXIBLE PAVEMENT SECTIONS Subgrade R-Value = 5 Asphalt Class 2 Concrete Aggregate Base Total Section Traffic Index (inches) (inches) Thickness (inches) 5.0 3.0 10.0 13.0 4.0 7.5 11.5 5.5 3.0 12.0 15.0 4.0 10.0 14.0 6.0 3.5 13.0 18.5 4.0 11.5 15.5 6.5 4.0 14.0 18.0 7.0 4.0 15.5 19.5 8.0 5.0 17.5 22.5

Materials

Class 2 Aggregate Base should conform to the requirements found in Caltrans Standard Specifications Section 26. The aggregate base should be placed in thin lifts in a manner to prevent segregation, uniformly moisture conditioned, and compacted to at least 95 percent relative compaction (using ASTM test methods) to provide a smooth, unyielding surface. Where the completed aggregate base section is exposed to periods of rainfall or extensive construction traffic prior to paving, the baserock should be proof-rolled with a loaded 10-wheel truck to locate any soft or yielding areas.

The asphalt concrete should comply with Caltrans Standard Specifications for ½” maximum, Type A for the surface course and ¾” maximum, Type A asphalt concrete for the base course where the asphalt concrete is placed in two lifts. Asphalt concrete should be placed and compacted in accordance with the specifications presented in Section 39 of the 2010 Caltrans Standard Specifications. To achieve proper compaction of asphalt concrete placed against concrete gutters and to reduce the potential that poorly compacted asphalt concrete pavement will drop below the concrete surface as the asphalt concrete is further compacted under the effects of vehicle traffic, the asphalt concrete should be placed such that the compacted surface is approximately ¼-inch above the concrete surface (excluding spill type gutters). If the paving machine is allowed to ride on the concrete gutter during asphalt concrete placement and the roller operator has the roller on the concrete during the compaction process, the asphalt concrete surface will appear to be compacted but will settle over time. This will result in water entering into the pavement structure, which can lead to accelerated pavement failure.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 31 Seepage Cut-Off And Pavement Section Drainage

Maintaining a drained condition at the pavement section is important to reduce the possibility of premature pavement failure due to saturation of the aggregate base and softening of the subgrade soils. Where cross-sloped pavements are planned with a spill-type curb and gutter section or a vertical curb at the upslope side of the pavement, in the absence of a requirement for a Class 2 Aggregate Base section below the curb, a deepened curb section extending 3 inches below the aggregate base/subgrade contact should be considered to act as a seepage cut-off to reduce the amount of water that enters the pavement structure. A pavement edge drain should be constructed under the catch-type curb and gutter along both sides of the roadway where crowned along the centerline, and along the low side of cross-sloped pavements. These subdrains will drain water that may collect and saturate the aggregate base, which could cause premature pavement failure. A pavement edge drain detail is provided on Plate 5 of this report.

ADDITIONAL GEOTECHNICAL ENGINEERING SERVICES

REMEDIAL GRADING PLAN

BSA should review the grading plan when it is near completion so that we can assist with the development of a remedial grading plan. It has been our experience that a remedial grading plan aids in the contractors’ understanding and implementation of the recommendations presented in a geotechnical report.

REVIEW OF PLANS AND SPECIFICATIONS

Prior to construction, our firm should be provided the opportunity to review the geotechnical aspects of the project structural, civil and landscape plans, and specifications, to determine if the recommendations of this report have been implemented in those documents.

EARTHWORK AND PAVING OBSERVATION AND TESTING

To a degree, the performance of the proposed project is dependent on the procedures and quality of the construction. Therefore, we should provide observations of the contractor's procedures and the exposed soil conditions, and field and laboratory testing during site preparation and grading, placement and compaction of fill, underground utility installation, and foundation and pavement construction. These observations will allow us to check the contractor's work for conformance with the intent of our recommendations and to observe unanticipated soil conditions that could require modification of our recommendations. We would appreciate the opportunity to meet with the contractors prior to the start of site grading, underground utility installation and pavement construction to discuss the procedures and methods of construction. This can facilitate the performance of the construction operation and minimize possible misunderstanding and construction delays.

BERLOGAR STEVENS & ASSOCIATES October 17, 2017 Job No. 3823.102 Page 32

LIMITATIONS

The conclusions and recommendations presented herein are based on the assumption that the data collected is representative of the subsurface conditions across the site. Site and subsurface conditions described in this report and presented on the boring, test pit and trench logs are those existing at the times of our field explorations and may not necessarily be representative of such conditions at other locations or times. It is not warranted that the logs are representative of such conditions elsewhere or at other times. This geotechnical investigation has been conducted in accordance with professional geotechnical engineering standards current at the time of service and in the geographic area of the site; no other warranty, expressed or implied, is offered or made.

The conclusions and recommendations presented in this report are based upon the project information provided to us by The Grupe Company, information obtained from published geologic reports and maps, unpublished geotechnical reports by others as identified in this report, subsurface conditions encountered at the borings, exploratory test pits and trench locations, the results of geotechnical laboratory testing, engineering analyses and professional judgment. It is not warranted that such information, interpretation of the data, and the conclusions and recommendations based on the interpretation of that data, will not be superseded by future Geotechnical Engineering developments. In addition to advancements in the field of Geotechnical Engineering, the International Building Code and the California Building Code are revised periodically. Those revisions can impact interpretation of subsurface soil conditions and regional seismicity, and may necessitate revisions to the recommendations presented in this report.

This geotechnical investigation has been conducted, and the opinions, conclusions and recommendations presented in this report were developed, in accordance with accepted Geotechnical Engineering practices that exist in the San Francisco Bay Area at the time this report was prepared. No warranty, expressed or implied, is offered, inferred or made, by or through our performance of professional services.

The information provided herein was developed for use by The Grupe Company for the project as described herein. In the event that changes in the nature, design or location of the proposed project are planned, it is found during construction that subsurface conditions differ from those described herein, or revisions are made to the Building Code that are related to Geotechnical Engineering, the conclusions and recommendations in this report shall be considered invalid, unless the changes are reviewed and the conclusions and recommendations are confirmed or modified in writing by BSA. In light of this, there is a practical limit to the usefulness of this report without critical review. Although the time limit for this review is strictly arbitrary, it is suggested that two years from the date of this report be considered a reasonable time for the usefulness of this report.

BERLOGAR STEVENS & ASSOCIATES PLATES

BERLOGAR STEVENS & ASSOCIATES

HAYWARD, CALIFORNIA BASE: PORTIONOF U.S.G.S.7.5MINUTETOPOGRAPHIC QUADRANGLE,

JOB NUMBER: 3823.102 DATE: 6-8-17 BY: CC 0 1"=2000' 2000 TENNYSON ROADEASTOFMISSIONBOULEVARD VICINITY MAP HAYWARD, CALIFORNIA THE GRUPECOMPANY TENNYSON FOR SITE PLATE 1 N JOB NUMBER: 3823.102 DATE: 6-20-17 DRAWN BY: CC

T-4

1 TR7 B-5

T-5 29

21 T-2 B-3

TR8

ET-3 21 36 B-4

T-1

TP-5

B-6 BSA FAULT B FAULT BSA T-6

T1 (2012)

L2 (2012)

T3 (1975) T3 B-2 32 "C" FAULT

T1(1975) TP-4

ET-2

T4 (1975) 29

T-3 T-7 ?

1' "B" FAULT

T-8

? ? 62

T-11 TP-1

B-1 T-9 FAULT 1 FAULT ? ENGEO

ET-1 BSA FAULT A FAULT BSA

T-2B

TP-3 T-12 37

TP-2

?

T-10 ?

1

? L2 (2012) ?

TP-5 T-12 T-2

B-6 T-2A

?

?

66 ? 1' T-2C

T-3 T-4

DEVELOPMENT AREA PROPERTY LINE ? LOCATION (C&A 2012) BORING LOCATION

(THIS STUDY) (BSA, 2017) CROSS SECTION LOCATION TEST PIT LOCATION TRENCH LOCATION APPROXIMATE TRENCH

?

T-2

?

FAULT "D" FAULT

40 ?

?

? T4 (1975) ? ET-3 T-16 TR8 T-4

(SOIL ENGINEERING CONSULTANTS, 1973) (JUDD HULL & ASSOCIATES, 1975) (EARTH SYSTEMS CONSULTANTS, 1980) (BERLOGAR GEOTECHNICAL (ENGEO, 2005) CONSULTANTS, 2001) APPROXIMATE TRENCH LOCATION APPROXIMATE TRENCH LOCATION APPROXIMATE TRENCH LOCATION APPROXIMATE TRENCH LOCATION APPROXIMATE TRENCH LOCATION

FAULT "E" FAULT

SUSPECTED

? FAULT "A" FAULT EXPLANATION FAULT HAZARD ZONE (ENGEO, 2005) (ENGEO, 2013) (BERLOGAR GEOTECHNICAL (2017) (BERLOGAR STEVENS & ASSOCIATES (STATE OF CALIFORNIA, 1982) CONSULTANTS, 2001) SOUTHWESTERN LIMIT OF EARTHQUAKE APPROXIMATE FAULT LOCATION APPROXIMATE FAULT LOCATION APPROXIMATE FAULT LOCATION APPROXIMATE FAULT LOCATION CONCENTRATED (BGC, 2001) HAYWARD FAULT ZONE

T-9

T-4B

66

37

T-1

T-14 1973) 1973) (SOIL ENGINEERING CONSULTANTS, (SOIL ENGINEERING CONSULTANTS, STRIKE AND DIP OF SHEAR STRIKE AND DIP OF SHEAR (ENGEO, 2005) APPROXIMATE FAULT LOCATION

T-4

T-13 T-3

T-15 Berlogar Stevens & Associates EAST OF MISSION BOULEVARD SOIL ENGINEERS * ENGINEERING GEOLOGISTS HAYWARD, CALIFORNIA THE GRUPE COMPANY SITE PLAN TENNYSON ROAD TENNYSON

0

1"=50'

FOR N

50

PLATE 2 ENGINEERED FILL GEOGRID REINFORCEMENT (TENSAR TX-7 OR APPROVED EQUIVALENT, 2 FOOT VERTICAL INTERMEDIATE BENCH SPACING, 20 FEET LONG) (SEE NOTE 1)

TOPSOIL, COLLUVIUM, OR SLIDE DEBRIS (TO BE REMOVED) 20 FEET (MAXIMUM)

ORIGINAL GRADE

SUBDRAIN (SEE NOTES 4,5,6) BENCHES 5 FEET SUBDRAIN (TYPICAL) (SEE NOTES 4,5) (SEE NOTE 2) KEYWAY 20 FEET MINIMUM NOT TO (SEE NOTE 3) SCALE 8 FEET MINIMUM

NOTES:

1. INTERMEDIATE BENCHES SHOULD BE SPACED EVERY 25 VERTICAL FEET ON SLOPES HIGHER THAN 30 FEET.

2. WHERE NATURAL GRADE IS STEEPER THAN 7:1, BENCH INTO STIFF SOIL OR BEDROCK AS DETERMINED BY SOIL ENGINEER. JOB NUMBER: 3823.102 DATE: 6-9-17 DRAWN BY: CC 3. KEYWAY SHOULD EXTEND AT LEAST 8 FEET BELOW EXISTING GRADE AT TOE OF SLOPE OR 4 FEET INTO STIFF SOIL OR BEDROCK WHICHEVER IS DEEPER, AS DETERMINED BY THE SOIL ENGINEER. KEYWAY WIDTH SHOULD BE A MINIMUM OF 20 FEET OR 1/2 OF THE FILL SLOPE HEIGHT, WHICHEVER IS GREATER.

4. NECESSITY OF KEYWAY SUBDRAIN AND INTERMEDIATE BENCH SUBDRAINS TO BE DETERMINED BY THE GEOTECHNICAL ENGINEER.

5. SUBDRAIN, IF NECESSARY, SHOULD DISCHARGE VIA A CLOSED PIPE TO STORM DRAIN OR SUITABLE OUTFALL.

6. SUBDRAIN, IF NECESSARY, SPACING MAXIMUM 20 FEET VERTICAL OR AS DETERMINED IN THE FIELD BY GEOTECHNICAL ENGINEER.

FILL SLOPE AND KEYWAY DETAIL

PLATE 3 18 INCHES MINIMUM

CLASS 2 PERMEABLE MATERIAL (NOTE 1)

PERFORATED PIPE (NOTE 2) 4 FEET MINIMUM KEYWAY AS APPROVED BY THE SOIL ENGINEER 6 INCHES

KEYWAY SUBDRAIN

18 INCHES MINIMUM

CLASS 2 PERMEABLE MATERIAL (NOTE 1) 4 FEET MINIMUM PERFORATED PIPE (NOTE 2)

6 INCHES

TRENCH SUBDRAIN

JOB NUMBER: 3823.102 DATE: 6-9-17 DRAWN BY: CC NOT TO SCALE

NOTES:

1. CLASS 2 PERMEABLE MATERIAL AS GIVEN IN STATE OF CALIFORNIA STANDARD SPECIFICATIONS.

2. PERFORATED PIPE PLACED PERFORATIONS DOWN, PVC PIPE WITH A MINIMUM DIAMETER OF SIX (6) INCHES, CONFORMING TO ASTM D-3034 SDR 35, FOR DEPTHS LESS THAN 30 FEET, AND SDR 23.5 FOR DEPTHS GREATER THAN 30 FEET.

TYPICAL SUBDRAIN DETAILS

PLATE 4 SCALE N.T.S.

CURB AND GUTTER CURB AND GUTTER ASPHALT CONCRETE ASPHALT CONCRETE

3 INCH DIAMETER SDR 23.5 OR PVC CLASS 2 SCHEDULE 40 CLASS 2 AGGREGATE BASE PERFORATED 4 INCHES AGGREGATE BASE PIPE MIN.

8 INCHES MINIMUM SUBGRADE SUBGRADE 12 INCHES CLASS 2 PERMEABLE MATERIAL

12 INCHES MINIMUM GEOTEXTILE WRAPPED DRAINAGE COMPOSITE (i.e. Multi-Flow, AdvanEdge)

ALTERNATIVE A ALTERNATIVE B

NOTES: 1. FOR CROWNED STREETS, PAVEMENT EDGE DRAIN TO BE INSTALLED ON BOTH SIDES OF STREET. FOR FIXED CROSS SLOPE STREETS, PAVEMENT EDGE DRAIN TO BE INSTALLED ON LOW SIDE OF STREET.

ALTERNATIVE A:

1. PERFORATED PIPE TO BE SURROUNDED BY AT LEAST 2 INCHES OF CLASS 2 PERMEABLE MATERIAL.

2. PERFORATED PIPE TO DISCHARGE INTO CATCH BASIN/DRAIN INLET.

3. PERFORATED PIPE TO BE LOCATED BELOW EXISTING SHALLOW UNDERGROUND UTILITIES WHERE THEY CROSS.

ALTERNATIVE B: JOB NUMBER: 3823.102 DATE: 6-9-17 DRAWN BY: CC

1. DRAINAGE COMPOSITE MAY BE PLACED DIRECTLY AGAINST CUT BANK AT THE PAVEMENT STRUCTURE EDGE SHOWN.

2. DRAINAGE COMPOSITE TO DISCHARGE INTO CATCH BASIN/DRAIN INLET.

3. DRAINAGE COMPOSITE TO BE LOCATED BELOW EXISTING SHALLOW UNDERGROUND UTILITIES WHERE THEY CROSS.

PAVEMENT EDGE DRAINS

PLATE 5 4 INCH 4 INCH 4 INCH GARAGE CAPILLARY CAPILLARY CAPILLARY BREAK BREAK BREAK

ANCHOR ANCHOR BOLT VAPOR RETARDER BOLT

MAXIMUM 2-1/2 FEET ENGINEERED FILL (TYPICAL)

MINIMUM TO BUILDING 2 LAYERS 15 MIL 6 INCHES PERIMETER PLASTIC SHEETING OR LIMITS OF 3 FEET BELOW DESIGNATED BOTTOM OF PT SLAB BUILDING ENVELOPE. JOB NUMBER: 3823.102 DATE: 6-9-17 DRAWN BY: CC DRAWN 6-9-17 DATE: 3823.102 NUMBER: JOB

FOUNDATION DECOUPLING DETAIL

PLATE 6 FINISH GRADE

12 INCHES

MIRADRAIN (PLASTIC TO WALL)

12 INCHES

JOB NUMBER: 3823.102 DATE: 6-16-17 DRAWN BY: CC PERFORATED PIPE (ENCAPSULATE WITH CLASS 2 PERMEABLE MATERIAL)

RETAINING WALL BACK DRAIN DETAIL

PLATE 7 DATE: 6-16-2017 JOB NUMBER: 3823.100

Cross-Section 1 – Slope Stability Analysis – Static Condition

PLATE 8 DATE: 6-16-2017 JOB NUMBER: 3823.100 JOB NUMBER:

Cross-Section 1 – Slope Stability Analysis – Pseudo-Static Condition

PLATE 9 APPENDIX A

Boring Logs and Key to Boring Logs

BERLOGAR STEVENS & ASSOCIATES

Berlogar Stevens & Associates BORING NUMBER B-1 5587 Sunol Boulevard PAGE 1 OF 1 Pleasanton, CA 94566 CLIENT The Grupe Company PROJECT NAME Ersted - Tennyson Property PROJECT NUMBER 3823.102 PROJECT LOCATION Hayward, CA DATE STARTED 3/21/17 COMPLETED 3/21/17 GROUND ELEVATION 161 ft DRILLING CONTRACTOR Pitcher Drilling GROUNDWATER: No Groundwater Encountered DRILLING METHOD Hollow Stem Auger 2.5" I.D. Split Barrel

LOGGED BY ROV Modified California Standard NOTES Sampler Penetration Test

MATERIAL DESCRIPTION (ft) (ft) (pcf) LIMIT USCS BLOW INDEX LIQUID DEPTH COUNT SAMPLER MOISTURE ELEVATION PLASTICITY PASSING #200 PASSING CONTENT (%) DRY UNIT WT. DRY UNIT 0 CONTENT FINES CL SILTY CLAY, gray-brown, moist to wet, stiff to very stiff, trace fine-to coarse-grained sand, trace fine gravel 160

11

CL SANDY CLAY, light gray-brown, moist, very stiff to hard, fine-to coarse-grained sand, 12 crushed rock fragments, trace fine gravel 5 below 4-1/2 feet, hard drilling

155 30

9

10

150 15 CL SILTY CLAY, gray-brown, moist, stiff, trace fine-to medium-grained sand, limonite stains Bottom of at 11.5 feet. BERLOGAR NO GROUNDWATER - GINT STD US.GDT - 6/20/17 14:13 - S:\PROJECTS\3823.102\3823.102 BORINGS.GPJ S:\PROJECTS\3823.102\3823.102 - 14:13 6/20/17 - US.GDT STD GINTGROUNDWATERNO - BERLOGAR A-1 Berlogar Stevens & Associates BORING NUMBER B-2 5587 Sunol Boulevard PAGE 1 OF 2 Pleasanton, CA 94566 CLIENT The Grupe Company PROJECT NAME Ersted - Tennyson Property PROJECT NUMBER 3823.102 PROJECT LOCATION Hayward, CA DATE STARTED 3/21/17 COMPLETED 3/21/17 GROUND ELEVATION 148 ft DRILLING CONTRACTOR Pitcher Drilling GROUNDWATER: No Groundwater Encountered DRILLING METHOD Hollow Stem Auger 2.5" I.D. Split Barrel

LOGGED BY ROV Modified California NOTES Sampler

MATERIAL DESCRIPTION (ft) (ft) (pcf) LIMIT USCS BLOW INDEX LIQUID DEPTH COUNT SAMPLER MOISTURE ELEVATION PLASTICITY PASSING #200 PASSING CONTENT (%) DRY UNIT WT. DRY UNIT 0 CONTENT FINES CL SILTY CLAY, gray-brown, moist, stiff, trace fine-to coarse-grained sand

145 15 below 3 feet, stiff to very stiff

20 94 25.0 5

32 CL SILTY CLAY, light cream-gray-brown, moist, very stiff, trace to some fine-to coarse-grained sand, fine gravel

140

10

20 113 19.0

135

15

27 113 17.0

130 CL SILTY CLAY, gray-brown, moist, hard, trace fine-to coarse-grained sand, trace fine gravel

BERLOGAR NO GROUNDWATER - GINT STD US.GDT - 6/20/17 14:13 - S:\PROJECTS\3823.102\3823.102 BORINGS.GPJ S:\PROJECTS\3823.102\3823.102 - 14:13 6/20/17 - US.GDT STD GINTGROUNDWATERNO - BERLOGAR 20 (Continued Next Page) A-2 Berlogar Stevens & Associates BORING NUMBER B-2 5587 Sunol Boulevard PAGE 2 OF 2 Pleasanton, CA 94566 CLIENT The Grupe Company PROJECT NAME Ersted - Tennyson Property PROJECT NUMBER 3823.102 PROJECT LOCATION Hayward, CA

MATERIAL DESCRIPTION (ft) (ft) (pcf) LIMIT USCS BLOW INDEX LIQUID DEPTH COUNT SAMPLER MOISTURE ELEVATION PLASTICITY PASSING #200 PASSING CONTENT (%) DRY UNIT WT. DRY UNIT 20 CONTENT FINES CL SILTY CLAY, gray-brown, moist, hard, trace fine-to coarse-grained sand, trace fine gravel (continued) 43 111 16.0

125

CLAYEY SILTSTONE, gray-brown, friable, highly fractured to crushed, partially decomposed into clay/silty clay 25

100

120

30

60-6

Bottom of borehole at 31.0 feet. BERLOGAR NO GROUNDWATER - GINT STD US.GDT - 6/20/17 14:13 - S:\PROJECTS\3823.102\3823.102 BORINGS.GPJ S:\PROJECTS\3823.102\3823.102 - 14:13 6/20/17 - US.GDT STD GINTGROUNDWATERNO - BERLOGAR A-3 Berlogar Stevens & Associates BORING NUMBER B-3 5587 Sunol Boulevard PAGE 1 OF 1 Pleasanton, CA 94566 CLIENT The Grupe Company PROJECT NAME Ersted - Tennyson Property PROJECT NUMBER 3823.102 PROJECT LOCATION Hayward, CA DATE STARTED 3/21/17 COMPLETED 3/21/17 GROUND ELEVATION 118 ft DRILLING CONTRACTOR Hand Auger GROUNDWATER: No Groundwater Encountered DRILLING METHOD Hollow Stem Auger 2.5" I.D. Split Barrel LOGGED BY KK NOTES

MATERIAL DESCRIPTION (ft) (ft) (pcf) LIMIT USCS BLOW INDEX LIQUID DEPTH COUNT SAMPLER MOISTURE ELEVATION PLASTICITY PASSING #200 PASSING CONTENT (%) DRY UNIT WT. DRY UNIT 0 CONTENT FINES CL SILTY CLAY, dark gray-brown, moist, medium stiff

115

5 GC/CL CLAYEY GRAVEL/GRAVELLY CLAY, light gray-brown, moist, medium dense to dense/very stiff

Bottom of borehole at 6.5 feet. BERLOGAR NO GROUNDWATER - GINT STD US.GDT - 6/20/17 14:13 - S:\PROJECTS\3823.102\3823.102 BORINGS.GPJ S:\PROJECTS\3823.102\3823.102 - 14:13 6/20/17 - US.GDT STD GINTGROUNDWATERNO - BERLOGAR A-4 Berlogar Stevens & Associates BORING NUMBER B-4 5587 Sunol Boulevard PAGE 1 OF 1 Pleasanton, CA 94566 CLIENT The Grupe Company PROJECT NAME Ersted - Tennyson Property PROJECT NUMBER 3823.102 PROJECT LOCATION Hayward, CA DATE STARTED 3/21/17 COMPLETED 3/21/17 GROUND ELEVATION 126 ft DRILLING CONTRACTOR Pitcher Drilling GROUNDWATER: No Groundwater Encountered DRILLING METHOD Hollow Stem Auger 2.5" I.D. Split Barrel

LOGGED BY ROV Modified California Standard NOTES Sampler Penetration Test

MATERIAL DESCRIPTION (ft) (ft) (pcf) LIMIT USCS BLOW INDEX LIQUID DEPTH COUNT SAMPLER MOISTURE ELEVATION PLASTICITY PASSING #200 PASSING CONTENT (%) DRY UNIT WT. DRY UNIT 0 CONTENT FINES CL SILTY CLAY, gray-brown, moist, stiff, trace fine-to medium-grained sand, 125

CL SILTY CLAY, light gray-brown, moist, stiff to very stiff, trace fine-to coarse-grained sand, trace fine gravel 20

23 5

120 CL SILTY CLAY, light gray, moist, very stiff, white and gray-brown mottling 33

CL SANDY CLAY, light green-gray, moist, very stiff, fine-to coarse-grained sand, trace fine gravel

10

115 34

Bottom of borehole at 11.5 feet. BERLOGAR NO GROUNDWATER - GINT STD US.GDT - 6/20/17 14:13 - S:\PROJECTS\3823.102\3823.102 BORINGS.GPJ S:\PROJECTS\3823.102\3823.102 - 14:13 6/20/17 - US.GDT STD GINTGROUNDWATERNO - BERLOGAR A-5 Berlogar Stevens & Associates BORING NUMBER B-5 5587 Sunol Boulevard PAGE 1 OF 1 Pleasanton, CA 94566 CLIENT The Grupe Company PROJECT NAME Ersted - Tennyson Property PROJECT NUMBER 3823.102 PROJECT LOCATION Hayward, CA DATE STARTED 3/21/17 COMPLETED 3/21/17 GROUND ELEVATION 117 ft DRILLING CONTRACTOR Pitcher Drilling GROUNDWATER: No Groundwater Encountered DRILLING METHOD Hollow Stem Auger 2.5" I.D. Split Barrel

LOGGED BY ROV Modified California Standard NOTES Sampler Penetration Test

MATERIAL DESCRIPTION (ft) (ft) (pcf) LIMIT USCS BLOW INDEX LIQUID DEPTH COUNT SAMPLER MOISTURE ELEVATION PLASTICITY PASSING #200 PASSING CONTENT (%) DRY UNIT WT. DRY UNIT 0 CONTENT FINES CL SILTY CLAY, gray-brown, moist, stiff, trace fine-to medium-grained sand

115 CL SILTY CLAY, white-gray, moist, stiff, trace medium-to coarse-grained sand, trace fine-to coarse gravel, caliche stains 13 86 21.0

14 5 below 5 feet, mixed with green-brown rock fragments 21

110

CL SILTY CLAY, gray-brown, moist, stiff, white and black mottling 10

19

105

15

35

Bottom of borehole at 16.5 feet. BERLOGAR NO GROUNDWATER - GINT STD US.GDT - 6/20/17 14:13 - S:\PROJECTS\3823.102\3823.102 BORINGS.GPJ S:\PROJECTS\3823.102\3823.102 - 14:13 6/20/17 - US.GDT STD GINTGROUNDWATERNO - BERLOGAR A-6 Berlogar Stevens & Associates BORING NUMBER B-6 5587 Sunol Boulevard PAGE 1 OF 2 Pleasanton, CA 94566 CLIENT The Grupe Company PROJECT NAME Ersted - Tennyson Property PROJECT NUMBER 3823.102 PROJECT LOCATION Hayward, CA DATE STARTED 3/21/17 COMPLETED 3/21/17 GROUND ELEVATION 116 ft DRILLING CONTRACTOR Pitcher Drilling GROUNDWATER: No Groundwater Encountered DRILLING METHOD Hollow Stem Auger 2.5" I.D. Split Barrel

LOGGED BY ROV Modified California NOTES Sampler

MATERIAL DESCRIPTION (ft) (ft) (pcf) LIMIT USCS BLOW INDEX LIQUID DEPTH COUNT SAMPLER MOISTURE ELEVATION PLASTICITY PASSING #200 PASSING CONTENT (%) DRY UNIT WT. DRY UNIT 0 CONTENT FINES CL SILTY CLAY, dark gray-brown, moist, stiff, trace fine-to coarse gravel 115

18 105 18.0

CL SILTY CLAY, light to medium gray-brown, moist, very stiff, some fine-to coarse-grained sand, trace fine gravel 37 5

110 38

10

105 43

below 14 feet, medium brown 15

100 40 113 13.0

CL SANDY CLAY, red-brown, moist, hard, fine-to coarse-grained sand, trace fine-to coarse gravel, some silt

BERLOGAR NO GROUNDWATER - GINT STD US.GDT - 6/20/17 14:13 - S:\PROJECTS\3823.102\3823.102 BORINGS.GPJ S:\PROJECTS\3823.102\3823.102 - 14:13 6/20/17 - US.GDT STD GINTGROUNDWATERNO - BERLOGAR 20 (Continued Next Page) A-7 Berlogar Stevens & Associates BORING NUMBER B-6 5587 Sunol Boulevard PAGE 2 OF 2 Pleasanton, CA 94566 CLIENT The Grupe Company PROJECT NAME Ersted - Tennyson Property PROJECT NUMBER 3823.102 PROJECT LOCATION Hayward, CA

MATERIAL DESCRIPTION (ft) (ft) (pcf) LIMIT USCS BLOW INDEX LIQUID DEPTH COUNT SAMPLER MOISTURE ELEVATION PLASTICITY PASSING #200 PASSING CONTENT (%) DRY UNIT WT. DRY UNIT 20 CONTENT FINES CL SANDY CLAY, red-brown, moist, hard, fine-to coarse-grained sand, trace fine-to coarse gravel, some silt (continued) 95 53

SC CLAYEY SAND with GRAVEL, light to medium gray-brown, saturated, dense, fine-to coarse-grained sand, fine-to coarse gravel

25

90 46 113 12.0

CLAYSTONE (highly weathered bedrock), green-brown, friable, crushed, low hardness 30

85 65

Bottom of borehole at 31.5 feet. BERLOGAR NO GROUNDWATER - GINT STD US.GDT - 6/20/17 14:13 - S:\PROJECTS\3823.102\3823.102 BORINGS.GPJ S:\PROJECTS\3823.102\3823.102 - 14:13 6/20/17 - US.GDT STD GINTGROUNDWATERNO - BERLOGAR A-8 APPENDIX B

Berlogar Stevens & Associates Exploratory Trench and Test Pit Logs

BERLOGAR STEVENS & ASSOCIATES

TRENCH T-7 TRENCH T-8 0 5 LOG OF NORTH WALL LOG OF NORTH WALL 75(1'1ƒ( 1"=5' 75(1'1ƒ( SOUTH END NORTH END SOUTH END NORTH END 0+00 0+10 0+20 0+30 0+40 0+00 0+10 0+20 0+30 0+40 0+50 0+60 0+70 0+80

LIGHT BROWN CLAY SEAM 145 CALCIUM CARBONATE 145 150 SHEAR WITH CALCIUM 150 A T-7 EXPLANATION A SERPENTINIZED BASALT CARBONATE 1/2 INCH GOUGE SEAM B BOLDER N48°W A GROUND SURFACE AND BOTTOM OF TRENCH C D B GEOLOGIC CONTACT, SOLID WHERE SHARP, DASHED B D WHERE APPROXIMATE 140 E 140 145 B C E 145 C C D CLAYEY SAND, MIXED MEDIUM TO DARK BROWN, SLIGHTLY A DAMP, LOOSE (FILL) FAULT D ELEVATION IN FEET ELEVATION IN FEET ELEVATION CALCIUM ELEVATION IN FEET RELIC BEDDING (?) ELEVATION IN FEET SILTY CLAY WITH ANGULAR ROCK FRAGMENTS, MEDIUM TO E-W 53°N N48°W 90° CARBONATE CALCIUM CARBONATE B LIGHT RED-BROWN, STIFF TO VERY STIFF CLAY GOUGE ANGULAR COBBLES OF SHEAR INFILLED SEEP SHEAR INFILLED VEIN STRINGERS SERPENTINITE WITH CALCIUM WITH CALCIUM 135 135 CARBONATE CLAY WITH SCATTERED COBBLES, MEDIUM TO DARK 140 CARBONATE 140 BROWN, MOIST, VERY STIFF, SCATTERED VEINS OF C CALCIUM CARBONATE CUTTING THROUGH RELIC BEDS(?), COBBLES ARE ROUNDED TO WELL-ROUNDED BASALT, TRENCH T-9 TRENCH T-9 SLIGHTLY WEATHERED WITH THIN WEATHERING RIND LOG OF NORTH WALL PARTIAL LOG OF SOUTH WALL GRAVELLY CLAY, WHITE TO LIGHT GRAY, DRY, STIFF TO NORTH END D VERY STIFF, CALCIUM CARBONATE BEDS MIXED WITH BLACK CLAY SOUTH END 75(1'1ƒ( NORTH END 0+80 0+70 0+60 0+50 0+00 0+10 0+20 0+30 0+40 0+50 0+60 0+70 0+80 0+90 G E CLAY, MEDIUM BROWN, MOIST, STIFF TO VERY STIFF 160 150 COMPLETELY WEATHERED T-8 EXPLANATION BASALT, BLACK I F A CAVING GROUND SURFACE AND BOTTOM OF TRENCH 155 155 GEOLOGIC CONTACT, SOLID WHERE SHARP, DASHED E-W 27°N 145 WHERE APPROXIMATE A ON SOUTH SIDE OF FAULT CLAY, WHITE, WET, E-W 27°N TRENCH SANDY CLAY, MEDIUM YELLOW-GRAY TO DARK CARBONATE RICH CLAY VERY STIFF, SOFT CLAY, BLUE, WET TO ELEVATION IN FEET A ORANGE-GRAY, MOIST, STIFF, SAND IS CALCIUM C VEIN, GRAY-BLUE TO BLUE, SATURATED, VERY SOFT CARBONATE NODULES, SOME DECOMPOSED QUARTZ B D SATURATED, VERY SOFT GRAVEL 150 150 ELEVATION IN FEET ELEVATION 140 G SANDY CLAY, LIGHT TO MEDIUM GRAY, CALCIUM B CARBONATE RICH, DRY, STIFF TO VERY STIFF E I BASALT, DARK GREEN BROWN, COMPLETELY WEATHERED, F C F SERPENTINIZED H SEEP CLAY WITH MINOR GRAVEL, RED TO ORANGE-BROWN, SEEP 145 145 ELEVATION IN FEET MOIST, STIFF TO VERY STIFF, GRAVEL IS WELL-ROUNDED HIGHLY FRACTURED, D QUARTZ, MANY VERTICAL CALCIUM CARBONATE HIGHLY WEATHERED, NORTH END STRINGERS NEAR TOP OF UNIT VOLCANIC ROCK 1+00 1+10 1+20 1+30 1+40 CLAY WITH PERVASIVE CALCIUM CARBONATE, MOTTLED E VERY DARK GRAY AND WHITE, DRY TO MOIST, VERY STIFF

140 T-10 EXPLANATION TRENCH T-10 TRENCH T-11 165 LOG OF NORTH WALL GROUND SURFACE AND BOTTOM OF TRENCH LOG OF NORTH WALL 75(1'1ƒ( 0+90 A 75(1'1ƒ( GEOLOGIC CONTACT, SOLID WHERE SHARP, DASHED SOUTH END NORTH END WHERE APPROXIMATE 0+00 0+10 0+20 SILTY CLAY, DARK GRAY-BROWN, MOIST, VERY SOFT TO 160 160 A SOFT 0+70 0+80 A SILTY CLAY, MEDIUM TO DARK GRAY TO BLACK, MOIST TO K B WET, STIFF TO VERY STIFF, CAVED IN CONCODIAL BLOCKS 6-10 INCH MAXIMUM DIAMETER J C ? SILTY TO SANDY CLAY, MEDIUM BROWN, MOIST, STIFF, ? B 155 155 C REMNANT BEDDING PARALLEL TO CALCIUM CARBONATE VEIN CALCIUM CARBONATE I VEIN N80°W 32°E 0+40 0+50 0+60 ELEVATION IN FEET ELEVATION IN FEET ELEVATION H A CARBONATE VEIN, G N57°W 27°E 150 150 CARBONATE VEIN, N55°W 88°N

SOUTH END H 0+00 0+10 0+20 0+30 COMPLETELY WEATHERED SERPENTINITE CLAY, GREEN, WET, SOFT TO 145 145 MEDIUM STIFF T-9 EXPLANATION JOB NUMBER: 3823.101 DATE: 3-17-17 DRAWN BY: CC BY: DRAWN 3-17-17 DATE: 3823.101 NUMBER: JOB

GROUND SURFACE AND BOTTOM OF TRENCH 140 F GEOLOGIC CONTACT, SOLID WHERE SHARP, DASHED T-11 EXPLANATION WHERE APPROXIMATE

SILTY CLAY, RED-BROWN, MOIST, STIFF GROUND SURFACE AND BOTTOM OF TRENCH A B SANDY CLAY WITH SCATTERED GRAVEL, MEDIUM A GEOLOGIC CONTACT, SOLID WHERE SHARP, DASHED 135 B RED-GRAY-BROWN, MOIST, STIFF TO VERY STIFF WHERE APPROXIMATE GRAVELLY SANDY CLAY, MEDIUM TO DARK BROWN, SOME POCKET PENTROMETER >3 A SILTY CLAY, DARK GRAY TO BLACK, MOIST, SOFT C CALCIUM CARBONATE STRINGERS, DRY TO MOIST, VERY

ELEVATION IN FEET ELEVATION STIFF, GRAVEL IS ANGULAR BASALT SILTY CLAY, DARK GRAY-BROWN WITH WHITE MOTTLING, B D MOIST, STIFF TO VERY STIFF, MOTTLING IS CALCIUM B SANDY CLAY, DARK GRAY TO BLACK, DRY, MEDIUM STIFF C ? CARBONATE UP TO 1 INCH DIAMETER D 130 CALCIUM CARBONATE, LIGHT GRAY TO WHITE, DRY, SILTY CLAY, MEDIUM ORANGE-BROWN, MOIST, STIFF C E FRIABLE, SLICKS ON CAVED SURFACE E CLAY, BLUE-GRAY WITH WHITE NODULES AND STREAKS OF SANDY CLAY WITH GRAVEL, RED-BROWN, MOIST D CALCIUM CARBONATE, MOIST, STIFF F SANDY CLAY, MEDIUM BROWN, MOIST, SOFT TO MEDIUM SILTY CLAY, MEDIUM ORANGE-BROWN, DRY, VERY STIFF TRENCH T-12 E G STIFF, RAGS, WOOD DEBRIS AT STATION 0+70 (FILL) 125 CLAY WITH SILT AND GRAVEL, MEDIUM OLIVE-BROWN TO SANDY CLAY WITH GRAVEL, DARK BROWN, MOIST, VERY LOG OF NORTH WALL BROWN-GRAY, DRY, VERY STIFF TO HARD, GRAVEL IS F H STIFF, GRAVEL IS ANGULAR BASALT TREND N-S ANGULAR SILTSTONE, SOME CALCIUM CARBONATE NORTH END NODULES UP TO 2-1/2 INCH DIAMETER I SILTY CLAY, RED-BROWN, DRY TO MOIST, VERY STIFF 0+30 0+40 0+50 0+60 0+70 SANDY CLAY WITH GRAVEL, MEDIUM TO LIGHT GRAY, DRY, G VERY STIFF, GRAVEL IS WELL ROUNDED AND BROKEN VOLCANIC ROCK (BASALT?) 160 H SILTSTONE, HIGHLY TO COMPLETELY WEATHERED, HIGHLY SOUTH END FRACTURED 0+00 0+10 0+20 A T-12 EXPLANATION I SILTY CLAY, ORANGE-BROWN, DRY, VERY STIFF TO HARD J SILTY CLAY, DARK GRAY AND BROWN, DRY, HARD, 155 GROUND SURFACE AND BOTTOM OF TRENCH CONTAINS STRETCHED CALCIUM CARBONATE STRINGERS G GEOLOGIC CONTACT, SOLID WHERE SHARP, DASHED CLAYSTONE, ORANGE-BROWN, DRY, HARD, CONTAINS TRENCH LOGS D F WHERE APPROXIMATE K CALCIUM CARBONATE NODULES APPROXIMATELY 1/2 INCH E DIAMETER A SILTY SANDY CLAY, DARK GRAY TO BLACK, DRY TO MOIST, STIFF TRENCH T-7 THROUGH T-12 C N48°E 25°N

150 150 ELEVATION IN FEET A B CLAY, LIGHT GRAY TO WHITE, MOIST, STIFF TENNYSON C SILTY CLAY, MEDIUM OLIVE-BROWN, DRY, VERY STIFF

C ROUNDED VOLCANIC SILTY CLAY WITH COBBLES, DARK GRAY-BROWN, DRY, HAYWARD, CALIFORNIA AND LIMESTONE D VERY STIFF, ABUNDANT CALCIUM CARBONATE NODULES ANGULAR COBBLES COBBLES, FRACTURED UP TO 1/2 INCH DIAMETER VOLCANIC ROCK FOR 145 B 145 E CLAY, GREEN-GRAY, MOIST TO WET, STIFF THE GRUPE COMPANY F CLAY, BLACK, MOIST, SOFT ELEVATION IN FEET ELEVATION G SILTY CLAY, ORANGE-BROWN, MOIST, STIFF TO VERY STIFF Berlogar Stevens & Associates 140 SOIL ENGINEERS * ENGINEERING GEOLOGISTS

PLATE 4 170

0 5

1"=5' TP-1 165 TREND N23°E SILTY CLAY, DARK 165 TP-2 GRAY-BLACK TO DARK TREND N18°W BROWN, MOIST, SOFT TO MEDIUM STIFF (COLLUVIUM) (POCKET PENTROMETER 1.5)

SILTY CLAY, MEDIUM BROWN, MOIST, ELEVATION IN FEET 160 SOFT TO MEDIUM STIFF (COLLUVIUM) 160 (POCKET PENTROMETER 1.5) SILTY CLAY, DARK GRAY-BLACK TO DARK BROWN, MOIST, SOFT CLAY, DARK GRAY TO BLACK WITH TO MEDIUM STIFF, ANGULAR WHITE MOTTLING, MOIST, STIFF, QUARTZ GRAVEL NEAR BASE ABUNDANT CALCIUM CARBONATE (COLLUVIUM) 155 NODULES UP TO 1 INCH DIAMETER (GRADATIONAL CONTACT ABOVE) ELEVATION IN FEET 155 SILTY CLAY, LIGHT TAN-BROWN, MOIST, STIFF (SHARP CONTACT ABOVE) CLAYEY GRAVEL, LIGHT BROWN, MOIST, DENSE, GRAVEL IS QUARTZ AND VOLCANIC TP-3 150 145 TREND N18°W 120 TP-4 SILTY CLAY, DARK TREND N5°W GRAY-BLACK TO DARK BROWN, MOIST, SOFT TO MEDIUM STIFF (COLLUVIUM)

ELEVATION IN FEET 140 SILTY CLAY, DARK SILTSTONE, MEDIUM BROWN-GRAY, 115 GRAY-BLACK , MOIST, HIGHLY WEATHERED, VERY CLOSE STIFF (COLLUVIUM) FRACTURING, WEAK, ROCK FRAGMENTS (POCKET HAVE WEATHERING RINDS AND IN PLACES, CLAY, BLUE-GRAY, MOIST, PENTROMETER 1.5) COMPLETELY WEATHERED, SOME ELEVATION IN FEET SERPENTINIZED ROCK WITH NOA FIBERS STIFF TO VERY STIFF CLAY, DARK GRAY TO BLACK WITH SILTY CLAY, MEDIUM WHITE MOTTLING, MOIST, CALCIUM ORANGE-BROWN, MOIST, VERY STIFF 110 CARBONATE NODULES UP TO 1 INCH (POCKET PENTROMETER 3.0) DIAMETER WITH CLUSTER OF 3 INCH, 135 (GRADATIONAL CONTACT ABOVE)

JOB NUMBER: 3823.101 DATE: 3-17-17 DRAWN BY: CC TP-5 TREND N29°E GRAPHIC TEST 130 SILTY CLAY, DARK EXPLANATION GRAY-BLACK TO DARK BROWN, MOIST, SOFT TO PIT LOGS MEDIUM STIFF (COLLUVIUM) GROUND SURFACE AND TEST PIT LIMITS

ELEVATION IN FEET (POCKET PENTROMETER 1.5) TENNYSON

GEOLOGIC CONTACT, SOLID WHERE HAYWARD, CALIFORNIA SILTY CLAY, LIGHT 125 BLUE-GRAY, MOIST, CLAY, DARK GRAY TO BLACK WITH SHARP, DASHED WHERE GRADATIONAL FOR VERY STIFF WHITE MOTTLING, MOIST, CALCIUM CARBONATE NODULES UP TO 1 INCH THE GRUPE COMPANY DIAMETER WITH CLUSTER OF 3 INCH, (GRADATIONAL CONTACT ABOVE) Berlogar Stevens & Associates SOIL ENGINEERS * ENGINEERING GEOLOGISTS

PLATE 5 APPENDIX C

Engeo Exploratory Trench Logs

BERLOGAR STEVENS & ASSOCIATES

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APPENDIX D

Geotechnical Laboratory Test Results

BERLOGAR STEVENS & ASSOCIATES

Direct Shear - ASTM D-3080

Project Name: Tennyson Project Number: 3823.102

Sample ID: B2 at 20-1/2ft Date Tested: 04/04/17

Material Description: Silty Clay Dark Gray Invoice Number: 15192

Sample Type: Undisturbed Test Type: CD Shear Rate, inches/min.: 0.00099

Maximum Dry Density, pcf: 0.0 Minimum Required Compaction, %: 0.0

Optimum Moisture Content, %: 0.0 Minimum Compacted Moisture Content, %: 0.0 Summary of Results

Normal Stress, psf: 1,500 3,500 0

Peak Shear Stress, psf: 1,158 1,722

Initial Dry Density, pcf: 110.9 112.1

Initial Moisture Content, %: 15.8 15.8

Final Moisture Content, %: 19.4 19.0

Peak Cohesion, (C' ), psf: 736 Peak Friction Angle, (Ф'peak), Degrees: 15.7

Graph of Shear Stress vs Normal Stress Peak Friction Angle 4,500

4,000

3,500

3,000

2,500

2,000 y = 0.2818x + 735.72

Shear Stress Shear (psf) 1,500

1,000

500

0 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500

Normal Stress (psf)

Berlogar Stevens & Associates Pleasanton, CA Direct Shear - ASTM D-3080

Project Name: Tennyson Project Number: 3823.102

Sample ID: B6 at 15-1/2ft Date Tested: 04/03/17

Material Description: Sandy Clay Dark Red Brown Invoice Number: 15192

Sample Type: Undisturbed Test Type: CD Shear Rate, inches/min.: 0.00099

Maximum Dry Density, pcf: 0.0 Minimum Required Compaction, %: 0.0

Optimum Moisture Content, %: 0.0 Minimum Compacted Moisture Content, %: 0.0 Summary of Results

Normal Stress, psf: 1,000 2,500

Peak Shear Stress, psf: 1,033 1,878

Initial Dry Density, pcf: 112.8 115.0

Initial Moisture Content, %: 12.8 12.8

Final Moisture Content, %: 16.1 16.0

Peak Cohesion, (C' ), psf: 470 Peak Friction Angle, (Ф'peak), Degrees: 29.4

Graph of Shear Stress vs Normal Stress Peak Friction Angle 4,500

4,000

3,500

3,000

2,500

2,000 y = 0.5635x + 469.61

Shear Stress Shear (psf) 1,500

1,000

500

0 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500

Normal Stress (psf)

Berlogar Stevens & Associates Pleasanton, CA Direct Shear Worksheet ASTM D-3080

Project Name: Tennyson Project Number: 3823.102

Sample ID: B6 at 25-1/2ft Date Tested: 04/05/17

Material Description: Sandy Clay with Gravel Yellow Brown Dark Brown Mix Invoice Number: 15192

Sample Type: Undisturbed Test Type: CD Shear Rate, inches/min.: 0.00099

Maximum Dry Density, pcf: 0.0 Minimum Required Compaction, %: 0.0

Optimum Moisture Content, %: 0.0 Minimum Compacted Moisture Content, %: 0.0 Summary of Results

Normal Stress, psf: 1,500 4,000 0

Peak Shear Stress, psf: 1,409 3,694

Initial Dry Density, pcf: 112.5 110.4

Initial Moisture Content, %: 12.3 12.3

Final Moisture Content, %: 14.5 14.6

Peak Cohesion, (C' ), psf: 37.5 Peak Friction Angle, (Ф'peak), Degrees: 42.5

Graph of Shear Stress vs Normal Stress Peak Friction Angle 4,500

4,000

y = 0.9142x + 37.568 3,500

3,000

2,500

2,000

Shear Stress Shear (psf) 1,500

1,000

500

0 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500

Normal Stress (psf)

Berlogar Stevens & Associates Pleasanton, CA TRIAXIAL COMPRESSION TEST - TXCU - ASTM D4767

Effective Stress 3.00

2.50

2.00 y = 0.3125x + 0.7

1.50

1.00 Shear Stress ShearStress (ksf)

0.50

0.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 Normal Stress (ksf)

Total Stress 3.00

2.50

2.00 y = 0.225x + 0.95 1.50

1.00 Shear Stress ShearStress (ksf)

0.50

0.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 Normal Stress (ksf)

Sample ID.: B2 at 10-11ft Sample Description: Silty Clay Light Olive Gray with Caliche

Specimen 1 2 Consolidaiton Pressure 749 2002 Consolidated Dry Density (pcf) 112.5 117.1 Consolidated Moisture Content (%) 19.2 17.8

Total Stress Cohesion (psf) 950 700 Friction Angle (degrees) 12.7 17.4 TRIAXIAL COMPRESSION TEST - TXCU - ASTM D4767

Effective Stress 3.00

2.50 y = 0.4x + 0.62 2.00

1.50

1.00 Shear Stress ShearStress (ksf)

0.50

0.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 Normal Stress (ksf)

Total Stress 3.00

2.50 y = 0.34x + 0.93 2.00

1.50

1.00 Shear Stress ShearStress (ksf)

0.50

0.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 Normal Stress (ksf)

Sample ID.: B6 at 5-6ft Sample Description: Sandy Clay with Gravel Red Brown

Specimen 1 2 Consolidaiton Pressure 504 1498 Consolidated Dry Density (pcf) 111.1 116.0 Consolidated Moisture Content (%) 18.2 17.9

Total Effective Stress Stress Cohesion (psf) 930 620 Friction Angle (degrees) 18.8 21.8 TRIAXIAL COMPRESSION TEST - TXCU - ASTM D4767

Effective Stress 3.00

2.50

2.00 y = 0.23x + 0.98

1.50

1.00 Shear Stress ShearStress (ksf)

0.50

0.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 Normal Stress (ksf)

Total Stress 3.00

2.50

2.00 y = 0.1375x + 1.25 1.50

1.00 Shear Stress ShearStress (ksf)

0.50

0.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 Normal Stress (ksf)

Sample ID.: B6 at 10-11ft Sample Description: Sandy Clay Red Brown

Specimen 1 2 Consolidaiton Pressure 504 2002 Consolidated Dry Density (pcf) 116.6 120.7 Consolidated Moisture Content (%) 16.8 15.1

Total Effective Stress Stress Cohesion (psf) 1250 980 Friction Angle (degrees) 7.8 13.0 Project Name: Tennyson Sample ID: B6 at 25ft Project Number: 3823.102 Invoice Number: 15192 Sample Description: Clayey Sand with Gravel Date Tested: 04/03/17

Gradation

100

90

80

70

60

50

Percent Passing 40

30

20

10

0 100.0 10.0 1.0 0.1 0.0

Sieve Opening, mm Tested By: gs Reported By: G. Suckow Berlogar Stevens & Associates Pleasanton, CA Gradation Test Data ASTM D 422

Project Name: Tennyson Project No: 3823.102 Comments: Date: 4/5/2017 Invoice Number: 15192 Tested By: gs Reported By: G. Suckow

12" 3" 1 1/2" 3/4" 3/8" #4 #8 #16 #30 #50 #100 #200 100

90

80

70

60

50

40

30

20

10

0 1000 100 10 1 0.1 0.01 0.001

COBBLES GRAVEL SAND SILT/CLAY

coarse fine coarse medium fine

ASTM D4318 Plasticity Symbol Sample ID Description Index:

B6 at 2-1/2ft CH Silty Clay Gray 41

Berlogar Stevens & Associates Pleasanton, CA Gradation Test Data ASTM D 422

Project Name: Tennyson Project No: 3823.102 Comments: Date: 4/12/2017 Invoice Number: 15206 Tested By: gs Reported By: G. Suckow

12" 3" 1 1/2" 3/4" 3/8" #4 #8 #16 #30 #50 #100 #200 100

90

80

70

60

50

40

30

20

10

0 1000 100 10 1 0.1 0.01 0.001

COBBLES GRAVEL SAND SILT/CLAY

coarse fine coarse medium fine

ASTM D4318 Plasticity Symbol Sample ID Description Index:

TP1 at 6ft CH Silty Clay with Sand Dark Gray Brown 43

Berlogar Stevens & Associates Pleasanton, CA Gradation Test Data ASTM D 422

Project Name: Tennyson Project No: 3823.102 Comments: Date: 4/12/2017 Invoice Number: 15206 Tested By: gs Reported By: G. Suckow

12" 3" 1 1/2" 3/4" 3/8" #4 #8 #16 #30 #50 #100 #200 100

90

80

70

60

50

40

30

20

10

0 1000 100 10 1 0.1 0.01 0.001

COBBLES GRAVEL SAND SILT/CLAY

coarse fine coarse medium fine

ASTM D4318 Plasticity Symbol Sample ID Description Index:

TP4 CL Sandy Clay Light Olive Gray 23

Berlogar Stevens & Associates Pleasanton, CA Atterberg Limits Test Data ASTM D 4318

Project Name: Tennyson Project Number: 3823.102

Sample ID: B6 at 2-1/2ft Date Tested: 04/05/17

Material Description: CH Silty Clay Gray Invoice Number: 15192 Summary of Test Results

Liquid Limit: 63 Plastic Limit: 22 Plasticity Index: 41

Classification: CH Fat Clay Liquid Limit Plastic Limit

Tare ID: E2 e3 e4 3c 1m 1e

Number Of Blows: 35 24 18 13

Tare Mass, (g): 13.82 13.61 13.69 13.61 11.46 11.68

Wet Soil + Tare Mass, (g): 18.77 18.45 19.74 19.89 13.17 14.03

Dry Soil + Tare Mass, (g): 16.91 16.58 17.39 17.44 12.87 13.61

Moisture Content, %: 60.2 63.0 63.5 64.0 21.3 21.8

Flow Curve Liquid Limit - Plasticity Chart

66 60

65

50 CH 64 "A" Line 63 40

62 (%)

61 30 CL

Content 60 20

59 Plasticity Index (PI) Index Plasticity

Moisture 58 10

57 MH & OH cl-ml ML & OL 56 25 0 10 25 100 10 20 30 40 50 60 70 80 90 100 Number of Blows Liquid Limit (LL)

Tested By: kk Reported By: G Suckow Berlogar Stevens & Associates Pleasanton, CA Atterberg Limits Test Data ASTM D 4318

Project Name: Tennyson Project Number: 3823.102

Sample ID: TP1 at 6ft Date Tested: 04/13/17

Material Description: CH Silty Clay with Sand Dark Gray Brown Invoice Number: 15206 Summary of Test Results

Liquid Limit: 63 Plastic Limit: 20 Plasticity Index: 43

Classification: CH Fat Clay Liquid Limit Plastic Limit

Tare ID: e1 e2 e3 e4 1 1e 1o

Number Of Blows: 34 26 19 16

Tare Mass, (g): 13.72 13.78 13.60 13.66 11.54 11.48 11.61

Wet Soil + Tare Mass, (g): 16.67 19.22 20.10 21.19 14.29 13.99 14.67

Dry Soil + Tare Mass, (g): 15.57 17.12 17.53 18.19 13.78 13.53 14.25

Moisture Content, %: 59.5 62.9 65.4 66.2 22.8 22.4 15.9

Flow Curve Liquid Limit - Plasticity Chart

67 60

66

50 CH 65 "A" Line 64 40

63 (%)

62 30 CL

Content 61 20

60 Plasticity Index (PI) Index Plasticity

Moisture 59 10

58 MH & OH cl-ml ML & OL 57 25 0 10 25 100 10 20 30 40 50 60 70 80 90 100 Number of Blows Liquid Limit (LL)

Tested By: kk Reported By: G Suckow Berlogar Stevens & Associates Pleasanton, CA Atterberg Limits Test Data ASTM D 4318

Project Name: Tennyson Project Number: 3823.102

Sample ID: TP4 Date Tested: 04/13/17

Material Description: CL Sandy Clay Light Olive Gray Invoice Number: 15206 Summary of Test Results

Liquid Limit: 42 Plastic Limit: 19 Plasticity Index: 23

Classification: CL Lean Clay Liquid Limit Plastic Limit

Tare ID: 6i 6l 6p 6f 1a 1d 1k

Number Of Blows: 34 26 21 15

Tare Mass, (g): 13.80 13.71 13.71 13.63 11.62 11.69 11.61

Wet Soil + Tare Mass, (g): 19.28 20.23 21.64 20.95 15.23 14.75 14.63

Dry Soil + Tare Mass, (g): 17.78 18.33 19.23 18.64 14.65 14.25 14.16

Moisture Content, %: 37.7 41.1 43.7 46.1 19.1 19.5 18.4

Flow Curve Liquid Limit - Plasticity Chart

47 60

46

50 CH 45 "A" Line 44 40

43 (%)

42 30 CL

Content 41 20

40 Plasticity Index (PI) Index Plasticity

Moisture 39 10

38 MH & OH cl-ml ML & OL 37 25 0 10 25 100 10 20 30 40 50 60 70 80 90 100 Number of Blows Liquid Limit (LL)

Tested By: kk Reported By: G Suckow Berlogar Stevens & Associates Pleasanton, CA Resistance Value ( R ) Value Test

ASTM D2844 and CalTrans CTM 301

Project Name: Tennyson Project Number: 3823.102

Sample ID: TP2 at 6 to 8-1/2ft Date Tested: 04/18/17

Area Sample Represents: Invoice Number: 15200

Material Description: Silty Clay with Sand Dark Brown with Caliche Reported By: G Suckow

Comments: Sample oozed from under mold by definition RV<5

Specimen Data Specimen A B C D Exudation Pressure, psi 439 Resistance Value ( R ) : <5 0 0 0 % Moisture at Test: 22.2 Dry Density at Test, pcf: 106.2 Expansion Dial, (0.0001"): 56 0 0 0 Expansion Pressure, psf: 248.1 Expansion Pressure at 300 psi: 0.0 psf R-Value at 300 psi Exudation Pressure: <5 Specification:

29

Exudation Pressure (psi)

1,800 1,700 1,600 1,500 1,400 1,300 1,200 1,100 1,000 900 800 700 600 500 400 300 200 100 0 100

90

80

70

60

50

40 Value - R 30

20

10

0

-10

-20

0 4 8 12 16 20 24 28 32

Berlogar Stevens & Associates Pleasanton, CA Unconfined Compressive Strength of Cohesive Soils: ASTM-D2166

Project Name: Tennyson Project Number: 3823.102

Sample ID: B2 at 4ft Date Reported: 4/3/2017

Sample Description: Silty Clay Dark Gray Brown Plastic Invoice Number: 15192 Comments: Summary of Results

Max. Stress, psf: Strain at Failure, %: Dry Density, pcf: 94.2 Moist. Content, %: 24.6

Test Data Percent Percent Strain Gauge Load, Strain Gauge Load, Strain, Stress, psf: Strain, Stress, psf: Reading, inches: lbs: Reading, inches: lbs: %: %: 0.000 0.0 - 0 0.300 86.1 5.7 2,541 0.010 4.7 0.2 147 0.340 0.020 0.380 0.030 21.3 0.6 663 0.420 0.040 27.2 0.8 845 0.460 0.050 32.9 1.0 1,020 0.500 0.060 38.8 1.1 1,201 0.540 0.070 44.2 1.3 1,365 0.580 0.080 50.9 1.5 1,569 0.620 0.090 56.7 1.7 1,745 0.660 0.100 61.4 1.9 1,885 0.700 0.120 70.2 2.3 2,147 0.740 0.140 75.7 2.7 2,307 0.780 0.160 81.1 3.1 2,461 0.820 0.180 85.2 3.4 2,576 0.860 0.200 88.5 3.8 2,665 0.900 0.220 90.8 4.2 2,723 0.240 92.2 4.6 2,754 0.260 92.2 5.0 2,743 0.280 90.2 5.4 2,673 Sample Data Sample Diameter, inch: 2.420 Sketch of Failure Wet Sample Mass, (g): 740.9 Sample Height, inch: 5.230 Wet Density, pcf: 117.4 Tare ID: 411 Tare Mass, (g): 73.9 Tare + Wet Sample Mass,(g): 814.5 Drilling Fracture Tare + Dry Sample Mass, (g): 668.2 Tested By: gs

Berlogar Stevens & Associates Pleasanton, CA Unconfined Compressive Strength of Cohesive Soils: ASTM-D2166

Project Name: Tennyson Project Number: 3823.102

Sample ID: B2 at 4ft Date Reported: 4/3/2017

Stress vs Strain Curve

5000

4000

3000

Stress (psf) Stress 2000

1000

0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Strain (%)

Tested By: gs Reported By: G Suckow Berlogar Stevens & Associates Pleasanton, CA Unconfined Compressive Strength of Cohesive Soils: ASTM-D2166

Project Name: Tennyson Project Number: 3823.102

Sample ID: B2 at 15ft Date Reported: 4/3/2017

Sample Description: Silty Clay Light Olive Gray Plastic Caliche Invoice Number: 15192 Comments: Summary of Results

Max. Stress, psf: Strain at Failure, %: Dry Density, pcf: 112.9 Moist. Content, %: 17.1

Test Data Percent Percent Strain Gauge Load, Strain Gauge Load, Strain, Stress, psf: Strain, Stress, psf: Reading, inches: lbs: Reading, inches: lbs: %: %: 0.000 0.0 - 0 0.300 114.7 5.1 3,407 0.010 18.3 0.2 572 0.340 119.4 5.8 3,522 0.020 28.6 0.3 892 0.380 123.7 6.5 3,622 0.030 36.8 0.5 1,146 0.420 127.6 7.2 3,709 0.040 44.4 0.7 1,381 0.460 130.8 7.8 3,774 0.050 51.2 0.9 1,589 0.500 133.5 8.5 3,823 0.060 57.0 1.0 1,766 0.540 135.8 9.2 3,860 0.070 62.7 1.2 1,940 0.580 138.4 9.9 3,905 0.080 66.0 1.4 2,038 0.620 139.9 10.6 3,917 0.090 70.0 1.5 2,158 0.660 141.3 11.2 3,926 0.100 73.2 1.7 2,253 0.700 142.5 11.9 3,929 0.120 79.8 2.0 2,447 0.740 143.8 12.6 3,934 0.140 85.2 2.4 2,604 0.780 144.7 13.3 3,928 0.160 89.9 2.7 2,738 0.820 144.8 14.0 3,900 0.180 95.1 3.1 2,886 0.860 144.8 14.7 3,869 0.200 99.2 3.4 3,000 0.900 145.0 15.3 3,844 0.220 103.1 3.7 3,107 0.240 106.3 4.1 3,192 0.260 109.3 4.4 3,270 0.280 111.5 4.8 3,324 Sample Data Sample Diameter, inch: 2.420 Sketch of Failure Wet Sample Mass, (g): 937.2 Sample Height, inch: 5.870 Wet Density, pcf: 132.3 Tare ID: 401 Tare Mass, (g): 75.0 Tare + Wet Sample Mass,(g): 1,009.2 Tare + Dry Sample Mass, (g): 872.6 Tested By: gs

Berlogar Stevens & Associates Pleasanton, CA Unconfined Compressive Strength of Cohesive Soils: ASTM-D2166

Project Name: Tennyson Project Number: 3823.102

Sample ID: B2 at 15ft Date Reported: 4/3/2017

Stress vs Strain Curve

5000

4000

3000

Stress (psf) Stress 2000

1000

0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Strain (%)

Tested By: gs Reported By: G Suckow Berlogar Stevens & Associates Pleasanton, CA Unconfined Compressive Strength of Cohesive Soils: ASTM-D2166

Project Name: Tennyson Project Number: 3823.102

Sample ID: B6 at 3-1/2ft Date Reported: 4/3/2017

Sample Description: Gravelly Clay Gray Brown Invoice Number: 15192 Comments: Summary of Results

Max. Stress, psf: Strain at Failure, %: Dry Density, pcf: 105.3 Moist. Content, %: 17.5

Test Data Percent Percent Strain Gauge Load, Strain Gauge Load, Strain, Stress, psf: Strain, Stress, psf: Reading, inches: lbs: Reading, inches: lbs: %: %: 0.000 0.0 - 0 0.300 0.010 16.4 0.2 513 0.340 0.020 26.7 0.3 833 0.380 0.030 36.8 0.5 1,146 0.420 0.040 47.0 0.7 1,462 0.460 0.050 54.9 0.8 1,704 0.500 0.060 61.9 1.0 1,918 0.540 0.070 66.5 1.2 2,057 0.580 0.080 70.8 1.3 2,187 0.620 0.090 75.0 1.5 2,313 0.660 0.100 78.7 1.7 2,423 0.700 0.120 85.0 2.0 2,608 0.740 0.140 89.8 2.3 2,745 0.780 0.160 93.6 2.7 2,852 0.820 0.180 95.6 3.0 2,903 0.860 0.200 95.6 3.4 2,893 0.900 0.220 94.0 3.7 2,834 0.240 91.0 4.0 2,734 0.260 89.0 4.4 2,665 0.280 Sample Data Sample Diameter, inch: 2.420 Sketch of Failure Wet Sample Mass, (g): 890.1 Sample Height, inch: 5.960 Wet Density, pcf: 123.7 Tare ID: 818 Tare Mass, (g): 111.0 Tare + Wet Sample Mass,(g): 997.6 Tare + Dry Sample Mass, (g): 865.4 Tested By: gs

Berlogar Stevens & Associates Pleasanton, CA Unconfined Compressive Strength of Cohesive Soils: ASTM-D2166

Project Name: Tennyson Project Number: 3823.102

Sample ID: B6 at 3-1/2ft Date Reported: 4/3/2017

Stress vs Strain Curve

5000

4000

3000

Stress (psf) Stress 2000

1000

0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Strain (%)

Tested By: gs Reported By: G Suckow Berlogar Stevens & Associates Pleasanton, CA