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HomeMy WebLinkAboutAppendix E - Geotechnical Due Diligence Evaluation Appendix E Geotechnical Due Diligence Evaluation GEOTECHNICAL DUE-DILIGENCE EVALUATION PROPOSED JEFFERSON FONTANA MIXED-USE DEVELOPMENT SOUTHWEST OF THE INTERSECTION OF JUNIPER AVENUE AND VALLEY BOULEVARD CITY OF FONTANA, CALIFORNIA Prepared For JPI COMPANIES 11988 El Camino Real, Suite 200San Diego, California 92130 Prepared By LEIGHTON AND ASSOCIATES, INC.10532 Acacia Street, Suite B-6Rancho Cucamonga, California 91730 Project No. 13584.001 June 24, 2022 June 24, 2022 Project No. 13584.001 JPI Companies 11988 El Camino Real, Suite 200 San Diego, California 92130 Attention: Mr. Jay Adamowitz Subject: Geotechnical Due-Diligence Evaluation, Proposed Jefferson Fontana Mixed-Use Development, Southwest of the Intersection of Juniper Avenue and Valley Boulevard, City of Fontana, California In accordance with your authorization, Leighton and Associates, Inc. (Leighton) has performed a geotechnical due-diligence evaluation of the proposed Jefferson Fontana mixed-use development, located southwest of Juniper Avenue and Valley Boulevard in the City of Fontana, California (San Bernardino County Assessor’s Parcel Numbers 0251-171-19, 0251-321-27, 02, 15, 16, 18, 19, 20, 21, 22, 23, 24, 25, 26, and portions of 03, 14, 29). Our evaluation included a review of the following report previously prepared for this project: SPC Geotechnical Inc., Geotechnical Investigation, AutoFit Fontana, 16655 Valley Boulevard, Fontana, 92335, Project No. SPC 8505-01, dated March 27, 2019. Based on our evaluation, construction of the proposed development is feasible from a geotechnical standpoint, provided the recommendations presented in this report are implemented. The most significant geotechnical issues for development of this project are those related to the potential for strong seismic shaking and potentially compressible soils. Good planning and design of the project can limit the impact of these constraints. This report presents our findings, conclusions, and geotechnical recommendations for the project. 13584.001 - 2 - We appreciate the opportunity to work with you on the development of this project. If you have any questions regarding this report, please contact us at your convenience. Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. Jim Cunneen, PE, C59444 Principal Engineer Jason D. Hertzberg, GE 2711 Principal Engineer Steven G. Okubo, CEG 2706 Senior Project Geologist JP/SGO/JT/JDH/rsm Distribution: (1) Addressee 13584.001 -i- TABLE OF CONTENTS Section Page 1.0 INTRODUCTION ...................................................................................................... 1 1.1 Site Location and Description .................................................................... 1 1.2 Proposed Development ............................................................................. 1 1.3 Purpose of Evaluation ................................................................................ 2 1.4 Scope of Evaluation ................................................................................... 2 2.0 FINDINGS ................................................................................................................ 4 2.1 Regional Geologic Conditions .................................................................... 4 2.2 Subsurface Soil Conditions ........................................................................ 4 2.2.1 Sulfate Content ............................................................................... 5 2.2.2 Resistivity, Chloride, and pH ........................................................... 5 2.3 Groundwater .............................................................................................. 6 2.4 Faulting and Seismicity .............................................................................. 6 2.4.1 Surface Faulting .............................................................................. 6 2.4.2 Seismic Design Parameters ............................................................ 7 2.5 Secondary Seismic Hazards ...................................................................... 8 2.5.1 Liquefaction Potential ...................................................................... 8 2.5.2 Seismically Induced Settlement ...................................................... 9 3.0 CONCLUSIONS AND RECOMMENDATIONS ...................................................... 11 3.1 General Earthwork and Grading .............................................................. 11 3.1.1 Site Preparation ............................................................................ 11 3.1.2 Overexcavation and Recompaction .............................................. 11 3.1.3 Fill Placement and Compaction..................................................... 12 3.1.4 Oversized Material ........................................................................ 13 3.1.5 Import Fill Soil ............................................................................... 13 3.1.6 Shrinkage and Subsidence ........................................................... 13 3.2 Shallow Foundation Recommendations................................................... 14 3.2.1 Minimum Embedment and Width .................................................. 15 3.2.2 Allowable Bearing ......................................................................... 15 3.2.3 Lateral Load Resistance ............................................................... 15 3.2.4 Increase in Bearing and Friction - Short Duration Loads ............... 15 3.2.5 Settlement Estimates .................................................................... 16 13584.001 -ii- 3.3 Recommendations for Slabs-On-Grade ................................................... 16 3.4 Post-Tensioned Foundation Recommendations ...................................... 18 3.5 Seismic Design Parameters ..................................................................... 19 3.6 Retaining Walls ........................................................................................ 19 3.7 Pavement Design .................................................................................... 21 3.8 Temporary Excavations ........................................................................... 22 3.9 Trench Backfill ......................................................................................... 22 3.10 Surface Drainage ..................................................................................... 23 3.11 Sulfate Attack and Corrosion Protection .................................................. 23 3.12 Additional Geotechnical Services ............................................................ 24 4.0 LIMITATIONS ........................................................................................................ 25 Figures (Rear of Text) Figure 1 - Site Location Map Figure 2 - Geotechnical Map Figure 3 - Regional Geology Map Figure 4 - Regional Faults and Historic Seismicity Map Figure 5 - Retaining Wall Subdrain Detail Appendices Appendix A - References Appendix B - SPC Exploratory Logs and Infiltration Logs Appendix C - SPC Laboratory Test Results Appendix D - Seismic Appendix E - General Earthwork and Grading Specifications 13584.001 - 1 - 1.0 INTRODUCTION 1.1 Site Location and Description This site consists of approximately 11.9 acres of land located at the southwest corner of Juniper Avenue and Valley Boulevard in the City of Fontana, California. The property is bounded to the north by Valley Boulevard, to the east by Juniper Avenue, and to the west and south by commercial and residential properties. The southernmost end of the property is bounded by Washington Drive, with Interstate 10 farther to the south. The site is relatively flat, slopes gently towards the south, and is currently vacant and undeveloped land. Based on review of historical imagery, a portion of the site has been historically occupied with agricultural and residential use from about 1938 to 1985 (NETR, 2022). Between 1985 and 1994, all structures were removed, and the site has remained vacant and undeveloped since. 1.2 Proposed Development Our understanding of this project is based on information you provided to us by email on May 23, 2022, and the provided preliminary Jefferson Fontana plan set, prepared by Architecture Design Collaborative, dated May 23, 2022. We understand that this project will include eight, 4-level buildings planned for multi- family residential and retail purposes. Based on the plan set, we understand that this development will consist of 464 one- to three- bedroom units, a 2-story leasing and amenity building, a 4,200-square-foot retail space, a recreation area, 671 parking stalls (which includes 184 individual garages on the ground floors of the buildings), and interior drive aisles. Previous Work SPC Geotechnical, Inc. (SPC) conducted a preliminary geotechnical investigation at this site for a then-proposed warehouse development in 2019. Exploration for their investigation included drilling, logging, and sampling of ten (10) exploratory borings, laboratory testing of representative soil samples, and providing conclusions and geotechnical recommendations for the development as proposed at that time. Based on their subsurface exploration, laboratory testing, 13584.001 - 2 - and analysis, SPC provided preliminary geotechnical recommendations for design and construction. As a part of their 2019 investigation, SPC conducted falling-head percolation testing in three borings, which extended to depths reaching approximately 3 feet below the surface. SPC’s reported unfactored infiltration rates of tested soils ranged from 1.1 in./hr. to 2.0 in./hr. Infiltration testing was conducted by SPC using shallow boring percolation test method. The approximate locations of SPC’s borings and infiltration test locations are shown on Figure 2, Geotechnical Map. Boring logs from SPC’s subsurface exploration are presented in Appendix B and results from SPC’s laboratory testing are presented in Appendix C. 1.3 Purpose of Evaluation The purpose of our geotechnical evaluation has been to evaluate geological and geotechnical conditions of the site based on a site visit to observe conditions from the surface; limited laboratory testing of a representative near-surface soil sample collected onsite; information collected from reports, maps, historical aerial imagery available from our in-house library and online; and the geotechnical report by SPC (2019) provided by you. 1.4 Scope of Evaluation The scope of our study has included the following tasks: • Background Review: We reviewed pertinent, readily available geologic and geotechnical literature covering the site, including the previously prepared geotechnical report pertaining to the Jefferson Fontana project (SPC, 2019). Our background review has also included regional geologic and seismic hazard maps and other online sources. Documents reviewed are listed in Appendix A. • Site Visit: We visited the site to observe current conditions from the surface and collected a bulk sample of near-surface soils. 13584.001 - 3 - • Laboratory Tests: We performed laboratory testing of the collected soil sample for soil corrosivity, which included screening of resistivity, sulfate content, chloride content, and pH. • Engineering Analysis: We analyzed data obtained from our background review, including data from previous field explorations and geotechnical laboratory testing (SPC, 2019), to develop geotechnical conclusions and provide recommendations presented in this report. • Report Preparation: Results of our geotechnical evaluation of this project have been summarized in this report, presenting our findings, conclusions and geotechnical recommendations for design and construction of the proposed development. 13584.001 - 4 - 2.0 FINDINGS 2.1 Regional Geologic Conditions The site is located on a gently sloping alluvial plain descending southward from the San Gabriel and San Bernardino Mountains. This area is within the Chino Basin in the northern portion of the Peninsular Ranges geomorphic province of California. The region is an area of crustal disturbance as the relatively northwestward-migrating Peninsular Ranges Province interacts with the Transverse Ranges Province (which includes the San Gabriel Mountains) to the north. Several active or potentially active faults have been mapped in the region and are believed to accommodate compression and lateral displacement associated with this crustal interaction. Major structural features surrounding the region include the Cucamonga Fault and the San Gabriel Mountains to the north, the inferred Fontana Seismic Trend to the west, and the San Jacinto Fault to the east. The site is located approximately 6.9 miles west of an active fault relating to the San Jacinto fault zone and 7.1 miles south of the active Cucamonga Fault Zone, which accommodates uplift that forms the steep escarpment of the San Gabriel Mountains to the north relative to the basin floor to the south. The closest potentially active fault to the site is the Fontana Seismic Trend which has been inferred to trace approximately 2.0 miles to the west of the project site. The site region is underlain by a thick accumulation of young alluvial fan deposits (Morton, 2003) consisting of pebbly and cobbly deposits that have been eroded and transported via Lytle Creek from the San Gabriel Mountains and deposited in the site vicinity. The surficial geologic units mapped in the vicinity of the site are shown on Figure 3, Regional Geology Map. 2.2 Subsurface Soil Conditions The onsite soils described by SPC (2019) included an approximately 3½-foot- thick layer of artificial fill at the surface that overlies young alluvial fan deposits to the maximum depth explored of 31.5 feet below the ground surface (bgs). Because a report documenting geotechnical observation and testing during previous rough grading is not available, we consider onsite artificial fill to be undocumented. The undocumented artificial fill onsite consisted of brown silty 13584.001 - 5 - fine to coarse sand with zones that included trace rounded gravel up to 2 inches in diameter, and was reported to generally be loose to medium dense. Young alluvial fan deposits were encountered below undocumented artificial fill and were described by SPC to consist of dry to moist, medium dense to very dense, brown, well-graded sand to silty sand with gravel. The gravel was found to be rounded, “fine to coarse” gravel, and generally encountered throughout the site. More detailed descriptions of the subsurface soil are presented on the exploratory logs in Appendix B. 2.2.1 Sulfate Content Water-soluble sulfates in soil can react adversely with concrete. However, concrete in contact with soil containing sulfate concentrations of less than 0.1 percent by weight is considered to have negligible sulfate exposure based on the American Concrete Institute (ACI) provisions, adopted by the 2019 CBC (CBC. 2019 and ACI, 2014). A near-surface soil sample was tested during our evaluation for soluble sulfate content. The result of this test indicated a sulfate content of less than 0.1 percent by weight, indicating negligible sulfate exposure (Exposure Class S0). As such, the soils exposed at pad grade are not expected to pose a significant potential for sulfate reaction with concrete. 2.2.2 Resistivity, Chloride, and pH Soil corrosivity to ferrous metals can be estimated by the soil’s electrical resistivity, chloride content and pH. In general, soil having a minimum resistivity between 1,000 and 2,000 ohm-cm is considered corrosive, and soil having a minimum resistivity less than 1,000 ohm-cm is considered severely corrosive. Soil with a chloride content of 500 parts-per-million (ppm) or more is considered corrosive to ferrous metals. As a screening for potentially corrosive soil, a soil sample was tested during our evaluation to determine minimum resistivity, chloride content, and pH. These tests indicated a minimum resistivity of 4,440 ohm-cm, a chloride content of 260 ppm, and a pH of 6.7 for the soils in that sample. Based on these results, the onsite soil is considered to be moderately corrosive to ferrous metals. 13584.001 - 6 - 2.3 Groundwater Groundwater was not observed onsite in SPC’s 2019 borings that extended to depths reaching approximately 31½ feet bgs. State Well No. 01S05W20N001S located approximately 0.6 mile southeast of the site indicated a historically highest groundwater level of 268 feet bgs based on measurements taken from October 1989 to September 2021. State Well No. 01S06W24R001S located approximately 0.8 mile southwest of the site indicated a historically highest groundwater level of 322 feet bgs based on measurements taken from March 1992 to September 2021. Fife et al. (1976) reported generalized depth to groundwater in 1960 to be between 400 and 500 feet below the project site. Based on review of available regional groundwater data, groundwater is expected to be greater than 50 feet below the project site. As such, groundwater is not expected to be a constraint to the proposed development. 2.4 Faulting and Seismicity In general, the primary seismic hazards for sites in the region include surface rupture along active faults and strong ground shaking. The potential for fault rupture and seismic shaking are discussed below. 2.4.1 Surface Faulting No active or potentially active faults have been previously mapped across or trending towards the project site nor is the site located within a current Alquist-Priolo or County Earthquake Fault Zone. Based on published mapping and our research, no active faults have been mapped on or trending toward the site. The closest mapped active or potentially active faults are presented in the following table. Fault Name Approximate Distance from Site San Jacinto 6.9 miles to the east Cucamonga 7.1 to the north San Andreas 11.1 miles to the northeast Based on our collected data, the potential for future surface rupture of active faults onsite is considered very low. 13584.001 - 7 - 2.4.2 Seismic Design Parameters The site is anticipated to experience strong ground shaking after the proposed project is developed resulting from an earthquake occurring along one or more of the major active or potentially active faults in southern California. Accordingly, the project should be designed in accordance with applicable current codes and standards utilizing the appropriate seismic design parameters to reduce seismic risk as defined by California Geological Survey (CGS) Chapter 2 of Special Publication 117a (CGS, 2008). Through compliance with these regulatory requirements and the utilization of appropriate seismic design parameters selected by the design professionals, potential effects relating to seismic shaking can be reduced. The following parameters should be considered for design under the 2019 CBC: 2019 CBC Parameters (CBC or ASCE 7-16 reference) Value 2019 CBC Site Latitude and Longitude: 34.0694, -117.4416 Site Class Definition (1613.2.2, ASCE 7-16 Ch 20) D** Mapped Spectral Response Acceleration at 0.2s Period (1613.2.1), Ss 1.813 g Mapped Spectral Response Acceleration at 1s Period (1613.2.1), S1 0.600 g Short Period Site Coefficient at 0.2s Period (T1613.2.3(1)), Fa 1.0 Long Period Site Coefficient at 1s Period (T1613.2.3(2)), Fv 1.7* Adjusted Spectral Response Acceleration at 0.2s Period (1613.2.3), SMS 1.813 g Adjusted Spectral Response Acceleration at 1s Period (1613.2.3), SM1 1.02* g Design Spectral Response Acceleration at 0.2s Period (1613.2.4), SDS 1.209 g Design Spectral Response Acceleration at 1s Period (1613.2.4), SD1 0.68* g Mapped MCEG peak ground acceleration (11.8.3.2, Fig 22-9 to 13), PGA 0.740 g Site Coefficient for Mapped MCEG PGA (11.8.3.2), FPGA 1.1 Site-Modified Peak Ground Acceleration (1803.5.12; 11.8.3.2), PGAM 0.814 g * Per Table 11.4-2 of Supplement 1 of ASCE 7-16, this value of Fv may only be used to calculate Ts [that note is not included in Table 1613A.2.3(2)]; note that SD1 and SM1 are functions of Fv. In addition, per Exception 2 of 11.4.8 of ASCE 7-16, special equations for Cs are required. This is in lieu of a site-specific ground motion hazard analysis per ASCE 7-16 Chapter 21.2. ** Site Class D, and all of the resulting parameters in this table, may only be used for structures without seismic isolation or seismic damping systems. 13584.001 - 8 - Based on the 2019 CBC Table 1613.2.3(2) footnote c., Fv should be determined in accordance with Section 11.4.8 of ASCE 7-16, since the mapped spectral response acceleration at 1 second is greater than 0.2g for Site Class D; in accordance with Section 11.4.8 of ASCE 7-16, a site- specific seismic analysis is required. However, the values provided in the table above may be utilized if design is performed in accordance with Exception (2) in Section 11.4.8 of ASCE 7-16, with special requirements for the seismic response coefficient (Cs), and Fv is only used for calculation of Ts. This exception does not apply (and the values in the table above would not be applicable) for proposed structures with seismic isolation or seismic damping systems. The project structural engineer should review the seismic parameters. A site-specific seismic ground motion analysis can be performed upon request. Hazard deaggregation was estimated using the USGS Interactive Deaggregations utility. The results of this analysis indicate that the predominant modal earthquake has a magnitude of approximately 8.1 (MW) at a distance on the order of 13 kilometers for the Maximum Considered Earthquake (2% probability of exceedance in 50 years). 2.5 Secondary Seismic Hazards In general, secondary seismic hazards for sites in the region could include soil liquefaction, earthquake-induced settlement, lateral displacement, landsliding, and earthquake-induced flooding. The potential for secondary seismic hazards at the site is discussed below. 2.5.1 Liquefaction Potential Liquefaction is the loss of soil strength or stiffness due to a buildup of pore-water pressure during severe ground shaking. Liquefaction is associated primarily with loose (low density), saturated, fine-to-medium grained, cohesionless soils. As the shaking action of an earthquake progresses, the soil grains are rearranged, and the soil densifies within a short period of time. Rapid densification of the soil results in a buildup of pore-water pressure. When the pore-water pressure approaches the total overburden pressure, the soil reduces greatly in strength and temporarily 13584.001 - 9 - behaves similarly to a fluid. Effects of liquefaction can include sand boils, settlement, and bearing capacity failures below structural foundations. The State of California has not assessed liquefaction hazards for this site. The County of San Bernardino has mapped the site to be outside of a zone of liquefaction susceptibility. Based on this and collected historic groundwater data indicating levels deeper than 50 feet bgs, onsite soils are not considered susceptible to liquefaction. 2.5.2 Seismically Induced Settlement Seismically induced settlement consists of dry dynamic settlement (above groundwater) and liquefaction-induced settlement (below groundwater). During a strong seismic event, seismically induced settlement can occur within loose to moderately dense sandy soil due to reduction in volume during and shortly after an earthquake event. Settlement caused by ground shaking is often nonuniformly distributed, which can result in differential settlement. We have performed analyses to estimate the potential for seismically induced settlement using the method of Tokimatsu and Seed, and based on Martin and Lew (1999), considering the maximum considered earthquake (MCE) peak ground acceleration (PGAM) based on data obtained from previous borings that SPC conducted at the project site. Design/historic high groundwater levels of 268 feet below ground surface were used in the analysis. Based on our analysis, a potential for approximately 3.9 inches of seismic settlement is estimated at the site; however, based on our overexcavation recommendations presented later in this report, the estimated potential seismic settlement is reduced to approximately 2.8 inches. Results of our seismic settlement analysis is presented in Appendix D. If the potential differential settlement is estimated as half of the total seismic settlement over a horizontal distance of 30 feet, this would result in a maximum of 1.4 inches of differential settlement in 30 feet (with overexcavation), or angular distortion of 0.0039L. This is below the differential settlement threshold of 0.010L for “other multi-story structures” 13584.001 - 10 - of Risk Category II, as listed in Table 12.13-3 of ASCE 7-16. “Other” buildings are those not constructed with concrete or masonry wall systems (i.e. wood- or steel-framed). The structural engineer should determine Structure Type and Risk Category and evaluate whether the differential settlement estimates described above are tolerable. A copy of ASCE 7-16 Table 12.13-3 is provided as follows for reference. Table 12.13-3 Differential Settlement Threshold Structure Type Risk Category I or II III IV Single-story structures with concrete or masonry wall systems 0.0075L 0.005L 0.002L Other single-story structures 0.015L 0.010L 0.002L Multistory structures with concrete or masonry wall systems 0.005L 0.003L 0.002L Other multistory structures 0.010L 0.006L 0.002L 13584.001 - 11 - 3.0 CONCLUSIONS AND RECOMMENDATIONS Based on our review collected data including those presented in SPC’s 2019 Geotechnical Investigation report, construction of the proposed residential development is feasible from a geotechnical standpoint provided that the recommendations presented in this report are implemented. No severe geologic or soils related issues were identified that would preclude development of the site for the proposed improvements. The most significant geotechnical issues at the site are those related to the potential for strong seismic shaking, presence of undocumented artificial fill and potentially compressible soils. Good planning and design of the project can limit the impact of these constraints. Remedial recommendations for these and other geotechnical issues are provided in the following sections. The recommendations contained herein are preliminary. Leighton should review site layouts of the proposed development to determine if our recommendations are applicable. 3.1 General Earthwork and Grading All grading should be performed in accordance with the General Earthwork and Grading Specifications presented in Appendix E unless specifically revised or amended below or by future recommendations based on final development plans. 3.1.1 Site Preparation Prior to construction, the site should be cleared of debris, which should be disposed of offsite. Any underground obstructions should be removed. Resulting cavities should be properly backfilled and compacted. 3.1.2 Overexcavation and Recompaction To reduce the potential for adverse differential settlement of the proposed improvements, the underlying subgrade soil should be prepared in such a manner that a uniform response to the applied loads is achieved. Prior to overexcavation and recompaction of onsite native soils, any clean undocumented artificial fill should be removed and may be used as 13584.001 - 12 - compacted fill for the project. Undocumented artificial fill has been estimated, based on observations of our borings, to reach depths of approximately 3.5 feet below the current ground surface. Localized areas of deeper undocumented artificial fill may be encountered during grading. In addition to the complete removals of undocumented artificial fill onsite and for structures with shallow foundations, we recommend that onsite alluvial soils be overexcavated and recompacted to a minimum depth of 3 feet below the bottom of the proposed footings or 8 feet below existing grade, whichever is deeper. Overexcavation and recompaction should extend a minimum horizontal distance of 8 feet from perimeter edges of the proposed footings (including columns connected to the buildings), or a distance equal to the depth of overexcavation below the footings, where feasible. Local conditions may require that deeper overexcavation be performed; such areas should be evaluated by Leighton during grading. Areas outside these overexcavation limits planned for asphalt or concrete pavement, flatwork, and site walls, and areas to receive fill should be overexcavated to a minimum depth of 24 inches below the existing ground surface or 12 inches below the proposed subgrade, whichever is deeper. In addition, all undocumented artificial fill should be overexcavated. After completion of the overexcavation, and prior to fill placement, the exposed surfaces should be scarified to a minimum depth of 6 inches, moisture conditioned to or slightly above optimum moisture content, and recompacted to a minimum 90 percent relative compaction, relative to the ASTM D 1557 laboratory maximum density. 3.1.3 Fill Placement and Compaction Onsite soil to be used for compacted structural fill should be free of organic material, debris, and oversized material (greater than 8 inches in largest dimension). Any soil to be placed as fill, whether onsite or imported material, should be reviewed and possibly tested by Leighton. 13584.001 - 13 - All fill soil should be placed in thin, loose lifts, moisture conditioned, as necessary to near optimum moisture content, and compacted to a minimum 90 percent relative compaction. Relative compaction should be determined in accordance with ASTM Test Method D1557. Aggregate base for pavement should be compacted to a minimum of 95 percent relative compaction. 3.1.4 Oversized Material Although materials larger than 2 inches in dimension were not reported by SPC (2019), young alluvial fan deposits in the area have the potential to include cobbles and boulders. If oversized rocks (larger than 12 inches in their largest dimension) are encountered during grading, special handling of these rocks will be recommended. During fill placement, rocks larger than 12 inches in their largest dimension should be removed from within 3 feet of finish grade. If encountered during grading, no rocks larger than 24 inches should be placed within 10 feet of finish grade. All rocks larger than 24 inches in greatest dimension should be placed in windrows, surrounded with sandy soils and placed with copious amounts of water or disposed of properly. The rock windrows should be placed such that individual rocks are not nested and sandy soil can be worked completely around the rocks. 3.1.5 Import Fill Soil If import soil is planned to be placed as fill, all import to be placed as fill should be geotechnically accepted by Leighton. Preferably at least 3 working days prior to proposed import to the site, the contractor should provide Leighton pertinent information of the proposed import soil, such as location of the soil, whether stockpiled or native in place, and pertinent geotechnical reports if available. 3.1.6 Shrinkage and Subsidence The change in volume of excavated and recompacted soil varies according to soil type and location. This volume change is represented as a percentage increase (bulking) or decrease (shrinkage) in volume of fill 13584.001 - 14 - after removal and recompaction. Subsidence occurs as in-place soil (e.g., natural ground) is moisture-conditioned and densified to receive fill, such as in processing an overexcavation bottom. Subsidence is in addition to shrinkage due to recompaction of fill soil. Field and laboratory data used in our calculations included laboratory-measured maximum dry densities for soil types encountered at the subject site (SPC, 2019), and our experience. We preliminarily estimate the following earth volume changes will occur during grading: Shrinkage (Approximate) 15±3 percent Subsidence (Approximate) (overexcavation bottom processing) 0.10 foot These estimates do not account for any removal of oversize material. The level of fill compaction, variations in the dry density of the existing soils and other factors influence the amount of volume change. It should be noted that subsidence, as referred to above, is settlement of in-place earth materials due to heavy equipment processing. It does not refer to potential settlement due to placement of additional loads from new fill (i.e., rising of grades). These shrinkage values are general guide values. Actual values will vary, due to the varying soil conditions and varying construction techniques. It is not possible to estimate exact values. Therefore, as with any grading project, some earthwork volume adjustments should be anticipated during grading. 3.2 Shallow Foundation Recommendations Conventional or post-tensioned slab foundations designed in accordance with the current California Building Code (CBC) may be used for the structures onsite. Foundation recommendations are provided in the following sections for a very low expansion potential. Overexcavation and recompaction of the building pad and footing subgrade should be performed as detailed in Section 3.1. 13584.001 - 15 - 3.2.1 Minimum Embedment and Width Based on our preliminary investigation, footings should have a minimum embedment per code requirements, with a minimum width of 24 inches for isolated and continuous footings. 3.2.2 Allowable Bearing An allowable bearing pressure of 2,000 pounds per square foot (psf) may be used, based on an assumed embedment depth of 12 inches and minimum width described above. This allowable bearing value may be increased by 250 psf per foot increase in depth or width to a maximum allowable bearing pressure of 3,500 psf. If higher bearing pressures are required, this should be reviewed on a case-by-case basis and may include additional overexcavation and/or soil reinforcement. These allowable bearing pressures are for total dead load and sustained live loads. Footing reinforcement should be designed by the structural engineer. 3.2.3 Lateral Load Resistance The soil resistance available to withstand lateral loads on a shallow foundation is a function of the frictional resistance along the base of the footing and the passive resistance that may develop as the face of the structure tends to move into the soil. The allowable frictional resistance between the base of the foundation and the subgrade soil may be computed using a coefficient of friction of 0.35. This value may be increased by one-third when considering loads of short duration, such as those imposed by wind and seismic forces. The allowable passive resistance may be computed using an allowable equivalent fluid pressure of 240 pounds per cubic foot (pcf), assuming there is constant contact between the footing and undisturbed soil. 3.2.4 Increase in Bearing and Friction - Short Duration Loads The allowable bearing pressure and coefficient of friction values may be increased by one-third when considering loads of short duration, such as those imposed by wind and seismic forces. 13584.001 - 16 - 3.2.5 Settlement Estimates The recommended allowable bearing pressure for shallow footings is generally based on a post-construction static settlement of 1 inch. Differential settlement is estimated to be on the order of ½ inch over a horizontal distance of 30 feet for shallow footings. Since settlement is a function of footing size and contact bearing pressure, differential settlement can be expected between adjacent columns or walls where a large differential loading condition exists. These settlement estimates should be considered by the designer during foundation design. Seismic differential settlement is estimated to be a maximum of approximately 1.4 inches over 30 feet for the design-level earthquake, or angular distortion of 0.0039L. The structural engineer should determine the Structure Type and Risk Category and evaluate whether the differential settlement estimates described above are tolerable. 3.3 Recommendations for Slabs-On-Grade Concrete slabs-on-grade should be designed by the structural engineer in accordance with the current CBC for soil with a low expansion potential. Where conventional light floor loading conditions exist, the following minimum recommendations should be used. More stringent requirements may be required by local agencies, the structural engineer, the architect, or the CBC. Laboratory testing should be conducted at finish grade to evaluate the expansion index of near-surface subgrade soils. In addition, slabs-on-grade should have the following minimum recommended components: • Subgrade Moisture Conditioning: The subgrade soil should be moisture conditioned to at least 2 percentage points above optimum moisture content to a minimum depth of 12 inches prior to placing the moisture vapor retarder, steel or concrete. • Moisture Retarder: A minimum of 15-mil moisture retarder should be placed below slabs where moisture-sensitive floor coverings or equipment is planned. The structural engineer should specify pertinent concrete design parameters and moisture migration prevention measures, such as whether a sand blotter layer should be placed over the vapor retarder. The moisture 13584.001 - 17 - barrier may be placed directly on subgrade provided gravel or other protruding objects that could puncture the moisture retarder are removed from the subgrade prior to placement. Moisture retarders can reduce, but not eliminate moisture vapor rise from the underlying soils up through the slab. Moisture retarders should be designed and constructed in accordance with applicable American Concrete Institute, Portland Cement Association, Post- Tensioning Institute, ASTM International, and California Building Code requirements and guidelines. • Concrete and Structural Design Thickness: Slabs-on-grade should be designed by the structural engineer, but should be at least 4 inches thick (this is referring to the actual minimum thickness, not the nominal thickness). Reinforcing steel should be designed by the structural engineer, but as a minimum (for conventionally reinforced slabs) should be No. 3 rebar placed at 18 inches on center, each direction, mid-depth in the slab. Minor cracking of the concrete as it cures, due to drying and shrinkage, is normal and should be expected. However, cracking is often aggravated by a high water/cement ratio, high concrete temperature at the time of placement, small nominal aggregate size, and rapid moisture loss due to hot, dry, and/or windy weather conditions during placement and curing. Cracking due to temperature and moisture fluctuations can also be expected. Low slump concrete can reduce the potential for shrinkage cracking. Additionally, our experience indicates that reinforcement in slabs and foundations can generally reduce the potential for concrete cracking. The structural engineer should consider these components in slab design and specifications. Moisture retarders can reduce, but not eliminate moisture vapor rise from the underlying soils up through the slab. Floor covering manufacturers should be consulted for specific recommendations. Leighton does not practice in the field of moisture vapor transmission evaluation, since this is not specifically a geotechnical issue. Therefore, we recommend that a qualified person, such as the flooring subcontractor and/or structural engineer, be consulted with to evaluate the general and specific moisture vapor transmission paths and any impact on the proposed construction. That person should provide recommendations for mitigation of 13584.001 - 18 - potential adverse impact of moisture vapor transmission on various components of the structures as deemed appropriate. 3.4 Post-Tensioned Foundation Recommendations Post-tensioned foundations for soils with a very low potential for expansion should be designed by a qualified structural engineer in accordance with the 2019 CBC (current code) and may use the spanability method. Expansion index (EI) should be confirmed upon completion of grading. For post-tension slab foundations, exterior footings (thickened edges) should have a minimum depth of 12 inches below the lowest adjacent soil grade and a minimum width of 12 inches. These footings may be designed for a maximum allowable bearing pressure of 2,000 pounds per square foot. The allowable bearing pressure may be increased by one-third for short-term loading. A lateral sliding coefficient of 0.35 may be used in the design. The recommended slab design parameters are based on the Post-Tensioning Institute Design of Post- Tensioned Slabs-on Ground, 3rd Edition with 2008 supplement (PTI DC10.1-08). The structural engineer should also design the post-tensioned slabs with adequate stiffness to minimize potential cracking in the slabs. The Post-Tensioning Institute (PTI) has recommended the following guidelines for residential development:  Initial landscaping should be done on all sides adjacent to the foundation. Positive drainage away from the foundation should be implemented and maintained.  Irrigation watering should be done in a uniform manner as equally as possible on all sides of the foundation to maintain constant soil moisture content. Ponding of irrigation or rainfall water adjacent to the foundation slab can cause differential soil moisture levels potentially leading to differential movements.  Planting trees closer to the structure than a distance equal to one-half the mature height of the tree could allow the root system to enter under the foundation. The root system could alter the soil moisture content within the soil and cause soil shrinkage, which may lead to differential movements of 13584.001 - 19 - the foundation. A landscape architect should be consulted and made aware of these recommendations. Based on the time of year and characteristics of onsite materials, near surface soils to a depth of at least 2 feet will dry rapidly during hot windy weather. Therefore, it is critical to long term performance of the foundations that the soil- moisture prior to construction and around the immediate perimeter of the slab after construction be maintained at 2 percent above optimum moisture content up through occupancy of the homes. All fill soils should be compacted to a minimum of 90 percent relative compaction. 3.5 Seismic Design Parameters Seismic parameters presented in this report should be considered during project design. In order to reduce the effects of ground shaking produced by regional seismic events, seismic design should be performed in accordance with the current CBC. The CBC seismic design parameters listed in Section 2.4 of this report should be considered for the seismic analysis of the subject site. 3.6 Retaining Walls The location and heights of retaining walls are not known at this time. The recommendation contained herein are applicable for retaining walls lower than 6 feet in retained soil height. We recommend that retaining walls be backfilled with very low expansive soil and constructed with a backdrain in accordance with the recommendations provided on Figure 5 (rear of text). Using expansive soil as retaining wall backfill will result in higher lateral earth pressures exerted on the wall. Based on these recommendations, the following parameters may be used for the design of conventional retaining walls up to 6 feet tall: Static Equivalent Fluid Weight (pcf) Condition Level Backfill Active 38 pcf At-Rest 58 pcf Passive (allowable) 260 pcf (Maximum of 3,500 psf) 13584.001 - 20 - The above values do not contain an appreciable factor of safety, so the structural engineer should apply the applicable factors of safety and/or load factors during design. Cantilever walls that are designed to yield at least 0.001H, where H is equal to the wall height, may be designed using the active condition. Rigid walls and walls braced at the top should be designed using the at-rest condition. Passive pressure is used to compute soil resistance to lateral structural movement. In addition, for sliding resistance, a frictional resistance coefficient of 0.35 may be used at the concrete and soil interface. The lateral passive resistance should be taken into account only if it is ensured that the soil providing passive resistance, embedded against the foundation elements, will remain intact with time. In addition to the above lateral forces due to retained earth, surcharge due to improvements, such as an adjacent structure or traffic loading, should be considered in the design of the retaining wall. Loads applied within a 1:1 projection from the surcharging structure on the stem of the wall should be considered in the design. A third of uniform vertical surcharge-loads should be applied at the surface as a horizontal pressure on cantilever (active) retaining walls, while half of uniform vertical surcharge-loads should be applied as a horizontal pressure on braced (at-rest) retaining walls. To account for automobile parking surcharge, we suggest that a uniform horizontal pressure of 100 psf (for restrained walls) or 70 psf (for cantilever walls) be added for design, where autos are parked within a horizontal distance behind the retaining wall less than the height of the retaining wall stem. For walls with a retained height over 6 feet, or where otherwise required by Code or deemed appropriate by the structural engineer, we recommend that the wall designs be checked seismically using an additive seismic Equivalent Fluid Pressure (EFP) of 25 pcf, which is added to the active EFP. The additive seismic EFP should be applied at the retained midpoint. Conventional retaining wall footings should have a minimum width of 24 inches and a minimum embedment of 12 inches below the lowest adjacent grade. An allowable bearing pressure of 2,000 psf may be used for retaining wall footing design, based on the minimum footing width and depth. This bearing value may 13584.001 - 21 - be increased by 250 psf per foot increase in width or depth to a maximum allowable bearing pressure of 3,500 psf. 3.7 Pavement Design Based on the design procedures outlined in the current Caltrans Highway Design Manual, and using an assumed design R-value of 50, flexible pavement sections may consist of the following for the Traffic Indices indicated. Final pavement design should be based on the Traffic Index determined by the project civil engineer and R-value testing provided near the end of grading. Asphalt Pavement Section Thickness, Type I Subgrade Soil Traffic Index (Street Type)* Asphaltic Concrete (AC) Thickness (inches) Class 2 Aggregate Base Thickness (inches) Total Pavement Section Thickness (inches) 5.5 (Local) 3.0 4.0 7.0 6.5 (Collector) 4.5** 4.0 8.5 9.0 (Secondary Highway) 6.5** 5.0 11.5 *As indicated in the City of Fontana’s Street Design Requirements, Standard Plan No. 402 ** Minimum asphalt thickness is 4.5 inches for collector streets and 6.5 inches for secondary highways as indicated in the City of Fontana’s Typical Undivided Street Sections, Standard Plan No. 400 All pavement construction should be performed in accordance with the Standard Specifications for Public Works Construction or Caltrans Specifications. Field observations and periodic testing, as needed during placement of the base course materials, should be undertaken to ensure that the requirements of the standard specifications are fulfilled. Prior to placement of aggregate base, the subgrade soil should be processed to a minimum depth of 6 inches, moisture-conditioned, as necessary, and recompacted to a minimum of 95 percent relative compaction. Aggregate base should be moisture conditioned, as necessary, and compacted to a minimum of 95 percent relative compaction. 13584.001 - 22 - If the pavement is to be constructed prior to construction of the structures, we recommend that the full depth of the pavement section be placed in order to support heavy construction traffic. 3.8 Temporary Excavations All temporary excavations, including utility trenches, retaining wall excavations and other excavations should be performed in accordance with project plans, specifications and all OSHA requirements. No surcharge loads should be permitted within a horizontal distance equal to the height of cut or 5 feet, whichever is greater from the top of the slope, unless the cut is shored appropriately. Excavations that extend below an imaginary plane inclined at 45 degrees below the edge of any adjacent existing site foundation should be properly shored to maintain support of the adjacent structures. Cantilever shoring should be designed based on an active equivalent fluid pressure of 40 pcf. If excavations are braced at the top and at specific design intervals, the active pressure may then be approximated by a rectangular soil pressure distribution with the pressure per foot of width equal to 25H, where H is equal to the depth of the excavation being shored. During construction, the soil conditions should be regularly evaluated to verify that conditions are as anticipated. The contractor should be responsible for providing the "competent person" required by OSHA, standards to evaluate soil conditions. Close coordination between the competent person and the geotechnical engineer should be maintained to facilitate construction while providing safe excavations. 3.9 Trench Backfill Utility-type trenches onsite can be backfilled with the onsite material, provided it is free of debris, significant organic material and oversized material. Prior to backfilling the trench, pipes should be bedded and shaded in a granular material that has a sand equivalent of 30 or greater. The sand should extend 12 inches above the top of the pipe. The bedding/shading sand should be densified in- place by mechanical means, or in accordance with Greenbook specifications. If gravel or open-graded rock is used as bedding or shading, it should be wrapped 13584.001 - 23 - in Mirafi 140N filter fabric to prevent soil from washing into the rock over the life of the project. The native backfill should be placed in loose layers, moisture conditioned, as necessary, and mechanically compacted using a minimum standard of 90 percent relative compaction. The thickness of layers should be based on the compaction equipment used in accordance with the Standard Specifications for Public Works Construction (Greenbook). 3.10 Surface Drainage Inadequate control of runoff water and/or poorly controlled irrigation can cause the onsite soils to expand and/or shrink, producing heaving and/or settlement of foundations, flatwork, walls, and other improvements. Maintaining adequate surface drainage, proper disposal of runoff water, and control of irrigation should help reduce the potential for future soil moisture problems. Positive surface drainage should be designed to be directed away from foundations and toward approved drainage devices, such as gutters, paved drainage swales, or watertight area drains and collector pipes. Surface drainage should be provided to prevent ponding of water adjacent to the structures. In general, the area around the buildings should slope away from the building. We recommend that unpaved landscaped areas adjacent to the buildings be avoided. Roof runoff should be carried to suitable drainage outlets by watertight drain pipes or over paved areas. 3.11 Sulfate Attack and Corrosion Protection Based on the results of laboratory testing performed, concrete structures in contact with the onsite soil will have “negligible” exposure (Exposure Class S0) to water-soluble sulfates in the soil. Therefore, concrete structures in contact with the on-site soils may be designed for negligible sulfate exposure (Exposure Class S0) in accordance with ACI 318 (ACI, 2014). If the concrete is expected to be in contact with reclaimed water, Type V cement and a water/cement ratio of 0.45 should be used. The onsite soil is considered to be moderately corrosive to ferrous metals. Corrosion information presented in this report should be provided to your underground utility subcontractors. Further testing for soluble sulfate content 13584.001 - 24 - should be conducted near or at the completion of the rough grading to verify the above. 3.12 Additional Geotechnical Services The preliminary geotechnical recommendations presented in this report are based on subsurface conditions as interpreted from limited subsurface explorations and limited laboratory testing. Our geotechnical recommendations provided in this report are based on information available at the time the report was prepared and may change as plans are developed. Additional geotechnical investigation and analysis may be required based on final improvement plans. Leighton should review the site and grading plans when available and comment further on the geotechnical aspects of the project. Geotechnical observation and testing should be conducted during excavation and all phases of grading operations. Our conclusions and preliminary recommendations should be reviewed and verified by Leighton and Associates, Inc. during construction and revised accordingly if geotechnical conditions encountered vary from our preliminary findings and interpretations. Geotechnical observation and testing should be provided: • After completion of site clearing. • During overexcavation of compressible soil. • During compaction of all fill materials. • After excavation of all footings and prior to placement of concrete. • During utility trench backfilling and compaction. • During pavement subgrade and base preparation. • When any unusual conditions are encountered. 13584.001 - 25 - 4.0 LIMITATIONS This due-diligence report was based in part on data obtained from SPC’s 2019 Geotechnical Investigation report, site visits, samples, and tests. Such information is, by necessity, incomplete. The nature of many sites is such that differing soil or geologic conditions can be present within small distances and under varying climatic conditions. Changes in subsurface conditions can and do occur over time. Therefore, our findings, conclusions, and recommendations presented in this report are based on the assumption that Leighton and Associates, Inc. will provide geotechnical observation and testing during construction. This report was prepared for the sole use of JPI Companies, for application to the design of the proposed residential development in accordance with generally accepted geotechnical engineering practices at this time in California. See the GBA insert on the following page for important information about this geotechnical engineering report. Geotechnical-Engineering Report Important Information about This Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes. While you cannot eliminate all such risks, you can manage them. The following information is provided to help. The Geoprofessional Business Association (GBA) has prepared this advisory to help you – assumedly a client representative – interpret and apply this geotechnical-engineering report as effectively as possible. In that way, clients can benefit from a lowered exposure to the subsurface problems that, for decades, have been a principal cause of construction delays, cost overruns, claims, and disputes. If you have questions or want more information about any of the issues discussed below, contact your GBA-member geotechnical engineer. Active involvement in the Geoprofessional Business Association exposes geotechnical engineers to a wide array of risk-confrontation techniques that can be of genuine benefit for everyone involved with a construction project. Geotechnical-Engineering Services Are Performed for Specific Purposes, Persons, and ProjectsGeotechnical engineers structure their services to meet the specific needs of their clients. A geotechnical-engineering study conducted for a given civil engineer will not likely meet the needs of a civil-works constructor or even a different civil engineer. Because each geotechnical-engineering study is unique, each geotechnical-engineering report is unique, prepared solely for the client. Those who rely on a geotechnical-engineering report prepared for a different client can be seriously misled. No one except authorized client representatives should rely on this geotechnical-engineering report without first conferring with the geotechnical engineer who prepared it. And no one – not even you – should apply this report for any purpose or project exceptthe one originally contemplated. Read this Report in FullCostly problems have occurred because those relying on a geotechnical-engineering report did not read it in its entirety. Do not rely on an executive summary. Do not read selected elements only. Read this report in full. You Need to Inform Your Geotechnical Engineer about ChangeYour geotechnical engineer considered unique, project-specific factors when designing the study behind this report and developing the confirmation-dependent recommendations the report conveys. A few typical factors include: •the client’s goals, objectives, budget, schedule, and risk-management preferences; •the general nature of the structure involved, its size, configuration, and performance criteria; •the structure’s location and orientation on the site; and •other planned or existing site improvements, such as retaining walls, access roads, parking lots, and underground utilities. Typical changes that could erode the reliability of this report include those that affect: •the site’s size or shape; •the function of the proposed structure, as when it’s changed from a parking garage to an office building, or from a light-industrial plant to a refrigerated warehouse; •the elevation, configuration, location, orientation, or weight of the proposed structure; •the composition of the design team; or •project ownership. As a general rule, always inform your geotechnical engineer of project changes – even minor ones – and request an assessment of their impact. The geotechnical engineer who prepared this report cannot accept responsibility or liability for problems that arise because the geotechnical engineer was not informed about developments the engineer otherwise would have considered. This Report May Not Be ReliableDo not rely on this report if your geotechnical engineer prepared it: •for a different client; •for a different project; •for a different site (that may or may not include all or a portion of the original site); or •before important events occurred at the site or adjacent to it; e.g., man-made events like construction or environmental remediation, or natural events like floods, droughts, earthquakes, or groundwater fluctuations. Note, too, that it could be unwise to rely on a geotechnical-engineering report whose reliability may have been affected by the passage of time, because of factors like changed subsurface conditions; new or modified codes, standards, or regulations; or new techniques or tools. If your geotechnical engineer has not indicated an “apply-by” date on the report, ask what it should be, and, in general, if you are the least bit uncertain about the continued reliability of this report, contact your geotechnical engineer before applying it. A minor amount of additional testing or analysis – if any is required at all – could prevent major problems. Most of the “Findings” Related in This Report Are Professional Opinions Before construction begins, geotechnical engineers explore a site’s subsurface through various sampling and testing procedures. Geotechnical engineers can observe actual subsurface conditions only at those specific locations where sampling and testing were performed. The data derived from that sampling and testing were reviewed by your geotechnical engineer, who then applied professional judgment to form opinions about subsurface conditions throughout the site. Actual sitewide-subsurface conditions may differ – maybe significantly – from those indicated in this report. Confront that risk by retaining your geotechnical engineer to serve on the design team from project start to project finish, so the individual can provide informed guidance quickly, whenever needed. This Report’s Recommendations Are Confirmation-DependentThe recommendations included in this report – including any options or alternatives – are confirmation-dependent. In other words, they are not final, because the geotechnical engineer who developed them relied heavily on judgment and opinion to do so. Your geotechnical engineer can finalize the recommendations only after observing actual subsurface conditions revealed during construction. If through observation your geotechnical engineer confirms that the conditions assumed to exist actually do exist, the recommendations can be relied upon, assuming no other changes have occurred. The geotechnical engineer who prepared this report cannot assume responsibility or liability for confirmation-dependent recommendations if you fail to retain that engineer to perform construction observation. This Report Could Be MisinterpretedOther design professionals’ misinterpretation of geotechnical-engineering reports has resulted in costly problems. Confront that risk by having your geotechnical engineer serve as a full-time member of the design team, to: •confer with other design-team members, •help develop specifications, •review pertinent elements of other design professionals’ plans and specifications, and •be on hand quickly whenever geotechnical-engineering guidance is needed. You should also confront the risk of constructors misinterpreting this report. Do so by retaining your geotechnical engineer to participate in prebid and preconstruction conferences and to perform construction observation. Give Constructors a Complete Report and GuidanceSome owners and design professionals mistakenly believe they can shift unanticipated-subsurface-conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent the costly, contentious problems this practice has caused, include the complete geotechnical-engineering report, along with any attachments or appendices, with your contract documents, but be certain to note conspicuously that you’ve included the material for informational purposes only. To avoid misunderstanding, you may also want to note that “informational purposes” means constructors have no right to rely on the interpretations, opinions, conclusions, or recommendations in the report, but they may rely on the factual data relative to the specific times, locations, and depths/elevations referenced. Be certain that constructors know they may learn about specific project requirements, including options selected from the report, only from the design drawings and specifications. Remind constructors that they may perform their own studies if they want to, and be sure to allow enough time to permit them to do so. Only then might you be in a position to give constructors the information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Conducting prebid and preconstruction conferences can also be valuable in this respect. Read Responsibility Provisions Closely Some client representatives, design professionals, and constructors do not realize that geotechnical engineering is far less exact than other engineering disciplines. That lack of understanding has nurtured unrealistic expectations that have resulted in disappointments, delays, cost overruns, claims, and disputes. To confront that risk, geotechnical engineers commonly include explanatory provisions in their reports. Sometimes labeled “limitations,” many of these provisions indicate where geotechnical engineers’ responsibilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closely. Ask questions. Your geotechnical engineer should respond fully and frankly. Geoenvironmental Concerns Are Not Covered The personnel, equipment, and techniques used to perform an environmental study – e.g., a “phase-one” or “phase-two” environmental site assessment – differ significantly from those used to perform a geotechnical-engineering study. For that reason, a geotechnical- engineering report does not usually relate any environmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated subsurface environmental problems have led to project failures. If you have not yet obtained your own environmental information, ask your geotechnical consultant for risk-management guidance. As a general rule, do not rely on an environmental report prepared for a different client, site, or project, or that is more than six months old. Obtain Professional Assistance to Deal with Moisture Infiltration and Mold While your geotechnical engineer may have addressed groundwater, water infiltration, or similar issues in this report, none of the engineer’s services were designed, conducted, or intended to prevent uncontrolled migration of moisture – including water vapor – from the soil through building slabs and walls and into the building interior, where it can cause mold growth and material-performance deficiencies. Accordingly, proper implementation of the geotechnical engineer’s recommendations will not of itself be sufficient to prevent moisture infiltration. Confront the risk of moisture infiltration by including building-envelope or mold specialists on the design team. Geotechnical engineers are not building-envelope or mold specialists. Copyright 2016 by Geoprofessional Business Association (GBA). Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with GBA’s specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of GBA, and only for purposes of scholarly research or book review. Only members of GBA may use this document or its wording as a complement to or as an element of a report of any kind. Any other firm, individual, or other entity that so uses this document without being a GBA member could be committing negligent Telephone: 301/565-2733 e-mail: info@geoprofessional.org www.geoprofessional.org ³ 0 2,000 4,000 Feet Scale:1 " = 2,000 ' Project: 13584.001 Eng/Geol: JDH/SGO Map Saved as J:\Drafting\13584\001\Maps\Geotech Report\13584-001_F01_SLM_2022-06-17.mxd on 6/17/2022 2:24:57 PM Author: KVM (btran) Date: June 2022 SITE LOCATION MAP Proposed Jefferson Fontana Mixed-useResidential DevelopmentSouthwest of the Intersection ofJuniper Avenue and Valley BoulevardCity of Fontana, California Approximate Site Boundary FIGURE 1 Reference: © 2022 Microsoft Corporation © 2022 Maxar ©CNES (2022) Distribution Airbus Map Saved as J:\Drafting\13584\001\Maps\Geotech Report\13584-001_F02_GM_2022-06-17.mxd on 6/17/2022 3:49:06 PM GEOTECHNICAL MAP Proposed Jefferson Fontana Mixed-use Residential Development Southwest of the Intersection of Juniper Avenue and Valley Boulevard City of Fontana, California ³ 0 100 200 Feet Scale: Base Map: Site Plan, Sheet A1.0, dated 05/23/2022 by Architecture Design Collaborative (ADC) 1 " = 100 ' Project: 13584.001 Eng/Geol: JDH/SGO Author: (btran) Date: June 2022 LEGEND &<Approximate location of boring &(Approximate location of infiltration test Approximate Site Boundary FIGURE 2 B-7 I-3 Qyf5 Scale: Reference: Geologic Map of the San Bernardino and Santa Ana Quadrangles, compiled by Douglas M. Morton and Fred K. Miller, 2006 1 " = 4,000 ' Project: 13584.001 Eng/Geol: JDH/SGO Map Saved as J:\Drafting\13584\001\Maps\Geotech Report\13584-001_F03_RGM_2022-06-17.mxd on 6/17/2022 2:29:19 PM Author: KVM (btran) Date: June 2022 REGIONAL GEOLOGY MAP Approximate Site Location Proposed Jefferson Fontana Mixed-useResidential DevelopmentSouthwest of the Intersection ofJuniper Avenue and Valley BoulevardCity of Fontana, California FIGURE 3 ³ 0 4,000 8,000 Feet Geologic Units Quaternary Age (Late Holocene) Young Alluvial Fan DepositsQyf Qof Quaternary Age (Late to Middle Pleistocene) Old Alluvial Fan Deposits ³ 0510 Miles Scale:1 " = 5 miles Project: 13584.001 Eng/Geol: JDH/SGO Map Saved as J:\Drafting\13584\001\Maps\Geotech Report\13584-001_F04_RFHSM_2022-06-17.mxd on 6/17/2022 2:32:54 PM Author: KVM (btran) Date: June 2022 REGIONAL FAULT AND HISTORIC SEISMICITY MAPProposed Jefferson Fontana Mixed-useResidential DevelopmentSouthwest of the Intersection ofJuniper Avenue and Valley BoulevardCity of Fontana, California Approximate Site Location Basemap Reference: © 2022 Microsoft Corporation Earthstar Geographics SIO © 2022 TomTomSeismicity Data Reference: maps.conservation.ca.gov LEGEND Fault activity Recency of Movement Historic (<200 years) Holocene (<11,700 years) Late Quaternary (last 700,000 years) Quaternary (<1.6M years) Historical Earthquakes (≥M3.5) !3.5 - 3.99 !4.0 - 4.99 !5.0 - 5.99 !6.0 - 6.99 !7+ FIGURE 4 APPENDIX A REFERENCES 13584.001 A-1 APPENDIX A References American Concrete Institute (ACI), 2014, Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary (ACE 318R-14), an ACI Standard. California Building Standards Commission, 2019, 2019 California Building Code, California Code of Regulations, Title 24, Part 2, Volume 2 of 2, Based on 2018 International Building Code, Effective January 1, 2020. California Department of Water Resources, 2022, California Statewide Groundwater Elevation Monitoring (CASGEM) Program, website: https://www.casgem.water.ca.gov/OSS/, accessed June 15, 2022. Fife, D.L., Morton, D.M., 1976, Geologic Hazards in Southwestern San Bernardino County, California, California Division of Mines and Geology Special Report 113. Morton, D.M., 2003, Preliminary Geologic Map of the Fontana 7.5’ Quadrangle, Riverside and San Bernardino Counties, California, U.S. Geological Survey Open-File Report OF-2003-418, scale 1:24,000. Office of Statewide Health Planning and Development (OSHPD) and Structural Engineers Association of California (SEAOC), 2021, Seismic Design Maps website: https://seismicmaps.org, accessed June 15, 2022. Public Works Standard, Inc., 2018, Greenbook, Standard Specifications for Public Works Construction: BNI Building News, Anaheim, California. SPC Geotechnical Inc., Geotechnical Investigation, AutoFit Fontana, 16655 Valley Boulevard, Fontana, 92335, Project No. SPC 8505-01, dated March 27, 2019. United States Geologic Survey (USGS), 2021, Earthquake Hazards Program, Unified Hazard Tool, website: https://earthquake.usgs.gov/hazards/interactive, accessed June 22, 2022. Youd, T.L., Idriss, I.M., Andrus, R.D., Arango, I., Castro, G., Christian, J.T., Dobry, R., Finn, L., Harder, L.F., Hynes, M.E., Ishihara, K., Koester, J.P., Liao, S.C., Marcuson, W.F. III, Martin, G.R., Mitchell, J.K., Moriwaki, Y., Power, M.S., Robertson, P.K., Seed, R.B., Stokoe, K.H. II, 2001, “Liquefaction Resistance of Soils: Summary Report from the 1996 NCEER and 1998 NCEER/NSF Workshops on Evaluation of Liquefaction Resistance of Soils”, Journal of Geotechnical and Geoenvironmental Engineering, Vol. 127, No. 10, October 2001. APPENDIX B SPC (2019) EXPLORATORY LOGS AND INFILTRATION LOGS FILL:Silty SAND (SM): Brown, moist, loose to medium dense, fine-grained sand, non-plastic fines ALLUVIUM:SAND with Gravel (SW): Brown, moist, medium dense, fine to coarse-grained sand, well-graded sand, roundedfine to coarse gravel, 2.5" maximum particle size4 3 2 1 0 30 118 3.9 26 Notes:1.) Boring drilled to 4.5'.2.) No seepage or groundwater encountered.3.) Excavation backfilled with cuttings and tamped. BORING LOG B-1 SPC 8505-01 Site Location:16655 Valley Boulevard, Fontana, CA 92335 Start:25 Feb 19 End:25 Feb 19 Estimated Surface Elevation: 1114'Total Depth:4.5'Water Depth:N/A Hole Diameter:8"Equipment:CME-45 / Hollow Stem Auger Logged By:PC Depth (Ft.) Sample Type BULK Field Blow Counts / Foot Moisture Content % Relative Compaction % Dry Density, Pcf Saturation % Graphic Log Description Boring Location: Near northwest corner of site, see Geotechnical Map, Plate 3. Project/Client:Valley Boulevard / AutoFit Inc. 1Sheet:of 1 Plate A-2 FILL:Silty SAND (SM): Dark brown, moist, loose to medium dense, non-plastic fines, trace rounded gravel, 2" maximum particle size @ 2': Increase in gravel content ALLUVIUM:SAND with Gravel (SW): Brown, dry to moist, medium dense, well-graded sand, fine to coarse rounded gravel @ 7': Similar to above Silty SAND (SM): Brown, moist, medium dense, fine-grained sand, non- to low plasticity fines SAND with Gravel (SW): Brown, dry to moist, very dense, fine to coarse-grained sand, well-graded sand, roundedto subrounded fine to coarse gravel @ 15': Change in color to dark grayish brown, increase in gravel content, cobble in sampler 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 46 20 36 62 124 111 116 129 2.9 2.9 3.3 1.8 23 16 21 17 BORING LOG B-2 SPC 8505-01 Site Location:16655 Valley Boulevard, Fontana, CA 92335 Start:25 Feb 19 End:25 Feb 19 Estimated Surface Elevation:1112'Total Depth:31.5'Water Depth:N/A Hole Diameter:8"Equipment:CME-45 / Hollow Stem Auger Logged By:PC Depth (Ft.) Sample Type BULK Field Blow Counts / Foot Moisture Content % Relative Compaction % Dry Density, Pcf Saturation % Graphic Log Description Boring Location: Near northwest corner of site, see Geotechnical Map, Plate 3. Project/Client:Valley Boulevard / AutoFit Inc. 1Sheet:of 2 Plate A-3 @ 20': Similar to above @ 25': No recovery SAND with Silt (SP-SM): Brown, dry to moist, dense, fine to medium-grained sand, poorly graded sand,predominantly fine-grained sand, coarse gravel, 1.5" maximum particle size 31 30 29 28 27 26 25 24 23 22 21 20 68 50/4" 39 124 107 2.2 2.2 17 11 Notes:1.) Boring drilled to 31.5'.2.) No seepage or groundwater encountered.3.) Excavation backfilled with cuttings and tamped. BORING LOG B-2 SPC 8505-01 Site Location:16655 Valley Boulevard, Fontana, CA 92335 Start:25 Feb 19 End:25 Feb 19 Estimated Surface Elevation:1112'Total Depth:31.5'Water Depth:N/A Hole Diameter:8"Equipment:CME-45 / Hollow Stem Auger Logged By:PC Depth (Ft.) Sample Type BULK Field Blow Counts / Foot Moisture Content % Relative Compaction % Dry Density, Pcf Saturation % Graphic Log Description Boring Location: Near northwest corner of site, see Geotechnical Map, Plate 3. Project/Client:Valley Boulevard / AutoFit Inc. 2Sheet:of 2 Plate A-3 FILL:Silty SAND (SM): Brown, moist, loose, fine to medium-grained sand, non-plastic fines@ 1': Becomes medium dense ALLUVIUM:SAND with Silt (SW-SM): Brown, moist, loose to medium dense, fine to coarse-grained sand, well-graded sand,non-plastic fines @ 5': Increase in gravel content Silty SAND (SM): Dark brown, wet, medium dense, fine to medium-grained sand, non-plastic fines SAND (SW): Grayish brown, moist, medium dense, fine to coarse-grained sand, well-graded sand, few roundedfine gravel 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 12 15 18 40 110 111 109 114 4.8 4.5 13.5 7.1 25 24 69 42 BORING LOG B-3 SPC 8505-01 Site Location:16655 Valley Boulevard, Fontana, CA 92335 Start:25 Feb 19 End:25 Feb 19 Estimated Surface Elevation:1106'Total Depth:31.5'Water Depth:N/A Hole Diameter:8"Equipment:CME-45 / Hollow Stem Auger Logged By:PC Depth (Ft.) Sample Type BULK Field Blow Counts / Foot Moisture Content % Relative Compaction % Dry Density, Pcf Saturation % Graphic Log Description Boring Location: Near southeast corner of site, see Geotechnical Map, Plate 3. Project/Client:Valley Boulevard / AutoFit Inc. 1Sheet:of 2 Plate A-4 SAND (SP) interbedded with Lean CLAY (CL): Light brown, moist, medium dense, fine-grained sand, poorlygraded sand, low plasticity fines Silty SAND (SM): Light brown, moist, medium dense, fine-grained sand, low plasticity fines @ 30': Similar to above 31 30 29 28 27 26 25 24 23 22 21 20 19 18 21 101 99 102 3.5 6.4 6.9 15 25 30 Notes:1.) Boring drilled to 31.5'.2.) Isolated seepage encountered at 10'.3.) Excavation backfilled with cuttings and tamped. BORING LOG B-3 SPC 8505-01 Site Location:16655 Valley Boulevard, Fontana, CA 92335 Start:25 Feb 19 End:25 Feb 19 Estimated Surface Elevation:1106'Total Depth:31.5'Water Depth:N/A Hole Diameter:8"Equipment:CME-45 / Hollow Stem Auger Logged By:PC Depth (Ft.) Sample Type BULK Field Blow Counts / Foot Moisture Content % Relative Compaction % Dry Density, Pcf Saturation % Graphic Log Description Boring Location: Near southeast corner of site, see Geotechnical Map, Plate 3. Project/Client:Valley Boulevard / AutoFit Inc. 2Sheet:of 2 Plate A-4 FILL:Silty SAND (SM): Brown, moist, loose to medium dense, non-plastic fines @ 1.5': Increase in gravel content, scattered rootlets ALLUVIUM:SAND with Gravel (SW): Dark grayish brown, moist, medium dense, rounded gravel, fine to coarse grained-sand, well-graded sand, 2" maximum particle size @ 5': Similar to above Silty SAND (SM): Brown, moist, medium dense, fine-grained sand, non-plastic fines @ 11': Decrease in moisture content @ 15': Increase in density 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 22 19 15 46 115 110 102 109 4.4 5.6 5.2 3.4 27 29 22 17 BORING LOG B-4 SPC 8505-01 Site Location:16655 Valley Boulevard, Fontana, CA 92335 Start:25 Feb 19 End:25 Feb 19 Estimated Surface Elevation:1113'Total Depth:31.5'Water Depth:N/A Hole Diameter:8"Equipment:CME-45 / Hollow Stem Auger Logged By:PC Depth (Ft.) Sample Type BULK Field Blow Counts / Foot Moisture Content % Relative Compaction % Dry Density, Pcf Saturation % Graphic Log Description Boring Location: Near northeast corner of site, see Geotechnical Map, Plate 3. Project/Client:Valley Boulevard / AutoFit Inc. 1Sheet:of 2 Plate A-5 Silty SAND with Gravel (SM): Dark grayish brown, dry to moist, medium dense to very dense, fine to coarse-grained sand, subrounded fine to coarse gravel, predominantly fine gravel SAND with Gravel (SW): Dark grayish brown, moist, medium dense, fine to coarse-grained sand, well-gradedsand, rounded fine to coarse gravel Silty SAND (SM): Brown, moist, medium dense, fine-grained sand, non-plastic fines31 30 29 28 27 26 25 24 23 22 21 20 58 73 28 102 118 108 2.1 2.2 10.5 9 15 53 Notes:1.) Boring drilled to 31.5'.2.) No seepage or groundwater encountered.3.) Excavation backfilled with cuttings and tamped. BORING LOG B-4 SPC 8505-01 Site Location:16655 Valley Boulevard, Fontana, CA 92335 Start:25 Feb 19 End:25 Feb 19 Estimated Surface Elevation:1113'Total Depth:31.5'Water Depth:N/A Hole Diameter:8"Equipment:CME-45 / Hollow Stem Auger Logged By:PC Depth (Ft.) Sample Type BULK Field Blow Counts / Foot Moisture Content % Relative Compaction % Dry Density, Pcf Saturation % Graphic Log Description Boring Location: Near northeast corner of site, see Geotechnical Map, Plate 3. Project/Client:Valley Boulevard / AutoFit Inc. 2Sheet:of 2 Plate A-5 FILL:Silty SAND (SM): Dark brown, moist, medium dense ALLUVIUM:SAND with Silt and Gravel (SW-SM): Brown, moist, medium dense, fine to-coarse grained sand, well-graded sand, rounded fine to coarse gravel, 2" maximum particle size @ 5': No recovery, cobble in shoe GRAVEL with Silt and Sand (GP): Gray, moist, medium dense, rounded fine to coarse gravel, poorly gradedgravel, fine to coarse-grained sand, non-plastic fines Silty SAND (SM): Light brown, moist, medium dense, fine-grained sand, non- to low plasticity fines 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 28 26 20 126 107 5.2 13.5 44 65 BORING LOG B-5 SPC 8505-01 Site Location:16655 Valley Boulevard, Fontana, CA 92335 Start:25 Feb 19 End:25 Feb 19 Estimated Surface Elevation:1109'Total Depth:20.9'Water Depth:N/A Hole Diameter:8"Equipment:CME-45 / Hollow Stem Auger Logged By:PC Depth (Ft.) Sample Type BULK Field Blow Counts / Foot Moisture Content % Relative Compaction % Dry Density, Pcf Saturation % Graphic Log Description Boring Location: Near center of site, see Geotechnical Map, Plate 3. Project/Client:Valley Boulevard / AutoFit Inc. 1Sheet:of 2 Plate A-6 GRAVEL with Silt and Sand (GP): Gray, moist, medium dense, rounded fine to coarse gravel, poorly gradedgravel, fine to coarse-grained sand, non-plastic fines20681193.1 21 Notes:1.) Boring drilled to 20.9'.2.) No seepage or groundwater encountered.3.) Excavation backfilled with cuttings and tamped. BORING LOG B-5 SPC 8505-01 Site Location:16655 Valley Boulevard, Fontana, CA 92335 Start:25 Feb 19 End:25 Feb 19 Estimated Surface Elevation:1109'Total Depth:20.9'Water Depth:N/A Hole Diameter:8"Equipment:CME-45 / Hollow Stem Auger Logged By:PC Depth (Ft.) Sample Type BULK Field Blow Counts / Foot Moisture Content % Relative Compaction % Dry Density, Pcf Saturation % Graphic Log Description Boring Location: Near center of site, see Geotechnical Map, Plate 3. Project/Client:Valley Boulevard / AutoFit Inc. 2Sheet:of 2 Plate A-6 FILL:Silty SAND (SM): Brown, moist, loose to medium dense, non-plastic fines, fine to coarse grained-sand ALLUVIUM:Silty SAND (SM): Brown, moist, medium dense, non-plastic fines, fine to coarse-grained sand, scattered gravel @ 10': Increase in fines content 11 10 9 8 7 6 5 4 3 2 1 0 9 11 106 110 7.1 11.6 34 60 Notes:1.) Boring drilled to 11.5'.2.) No seepage or groundwater encountered.3.) Excavation backfilled with cuttings and tamped. BORING LOG B-6 SPC 8505-01 Site Location:16655 Valley Boulevard, Fontana, CA 92335 Start:25 Feb 19 End:25 Feb 19 Estimated Surface Elevation:1109'Total Depth:11.5'Water Depth:N/A Hole Diameter:8"Equipment:CME-45 / Hollow Stem Auger Logged By:PC Depth (Ft.) Sample Type BULK Field Blow Counts / Foot Moisture Content % Relative Compaction % Dry Density, Pcf Saturation % Graphic Log Description Boring Location: At east side of site, see Geotechnical Map, Plate 3. Project/Client:Valley Boulevard / AutoFit Inc. 1Sheet:of 1 Plate A-7 FILL:Silty SAND (SM): Olive brown, moist, loose to medium dense, fine to coarse-grained sand, predominantly fine to medium-grained, with rounded fine to coarse gravel, 2" maximum particle size ALLUVIUM:SAND with Silt and Gravel (SW): Brown, moist, medium dense, medium to coarse-grained sand, well-graded sand, decrease in fines content Silty SAND (SM): Brown, moist, medium dense, fine to medium-grained sand, non- to low plasticity fines, slatefragment in shoe @ 10': Similar to above @ 15': Increase in fines content, sand becomes fine-grained 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 16 14 17 32 119 114 108 106 9.2 6.7 10.7 10.4 62 40 53 50 BORING LOG B-7 SPC 8505-01 Site Location:16655 Valley Boulevard, Fontana, CA 92335 Start:25 Feb 19 End:25 Feb 19 Estimated Surface Elevation:1106'Total Depth:31.5'Water Depth:N/A Hole Diameter:8"Equipment:CME-45 / Hollow Stem Auger Logged By:PC Depth (Ft.) Sample Type BULK Field Blow Counts / Foot Moisture Content % Relative Compaction % Dry Density, Pcf Saturation % Graphic Log Description Boring Location: Near southwest corner of site, see Geotechnical Map, Plate 3 Project/Client:Valley Boulevard / AutoFit Inc. 1Sheet:of 2 Plate A-8 @ 20': No recovery, likely due to presence of gravel/cobbles SAND with Gravel (SW): Brown, dry to moist, dense, fine to coarse-grained sand, well-graded sand, rounded fineto coarse gravel, 2" maximum particle size Sandy SILT (ML): Brown, moist, hard, non- to low plasticity fines, fine-grained sand @ 30': Similar to above 31 30 29 28 27 26 25 24 23 22 21 20 70 40 26 107 103 4.2 7.1 21 31 Notes:1.) Boring drilled to 31.5'.2.) No seepage or groundwater encountered.3.) Excavation backfilled with cuttings and tamped. BORING LOG B-7 SPC 8505-01 Site Location:16655 Valley Boulevard, Fontana, CA 92335 Start:25 Feb 19 End:25 Feb 19 Estimated Surface Elevation:1106'Total Depth:31.5'Water Depth:N/A Hole Diameter:8"Equipment:CME-45 / Hollow Stem Auger Logged By:PC Depth (Ft.) Sample Type BULK Field Blow Counts / Foot Moisture Content % Relative Compaction % Dry Density, Pcf Saturation % Graphic Log Description Boring Location: Near southwest corner of site, see Geotechnical Map, Plate 3 Project/Client:Valley Boulevard / AutoFit Inc. 2Sheet:of 2 Plate A-8 FILL:Silty SAND (SM): Brown, moist, loose to medium dense ALLUVIUM:Silty SAND (SM): Brown, moist, medium dense, scattered fine to coarse gravel 3 2 1 0 Notes:1.) Boring drilled to 3.1'.2.) No seepage or groundwater encountered.3.) Boring utilized for infiltration testing.4.) Excavation backfilled with cuttings and tamped on 2/26/2019. BORING LOG I-1 SPC 8505-01 Site Location:16655 Valley Boulevard, Fontana, CA 92335 Start:25 Feb 19 End:25 Feb 19 Estimated Surface Elevation:1108'Total Depth:3.1'Water Depth:N/A Hole Diameter:8"Equipment:CME-45 / Hollow Stem Auger Logged By:PC Depth (Ft.) Sample Type BULK Field Blow Counts / Foot Moisture Content % Relative Compaction % Dry Density, Pcf Saturation % Graphic Log Description Boring Location: At west side of site, see Geotechnical Map, Plate 3. Project/Client:Valley Boulevard / AutoFit Inc. 1Sheet:of 1 Plate A-9 FILL:Silty SAND (SM): Brown, moist, loose to medium dense; fine to coarse-grained sand, predominantly fine tomedium-grained sand, non-plastic fines ALLUVIUM:Silty SAND (SM): Brown, moist, medium dense; fine to coarse-grained sand, predominantly fine tomedium-grained sand, non-plastic fines, scattered fine to coarse gravel3 2 1 0 Notes:1.) Boring drilled to 3.1'.2.) No seepage or groundwater encountered.3.) Boring utilized for infiltration testing.4.) Excavation backfilled with cuttings and tamped on 2/26/2019. BORING LOG I-2 SPC 8505-01 Site Location:16655 Valley Boulevard, Fontana, CA 92335 Start:25 Feb 19 End:25 Feb 19 Estimated Surface Elevation:1105'Total Depth:3.1'Water Depth:N/A Hole Diameter:8"Equipment:CME-45 / Hollow Stem Auger Logged By:PC Depth (Ft.) Sample Type BULK Field Blow Counts / Foot Moisture Content % Relative Compaction % Dry Density, Pcf Saturation % Graphic Log Description Boring Location: At south side of site, see Geotechnical Map, Plate 3. Project/Client:Valley Boulevard / AutoFit Inc. 1Sheet:of 1 Plate A-10 FILL:Silty SAND (SM): Brown, moist, loose to medium dense; fine to coarse-grained sand, non-plastic fines ALLUVIUM:Silty SAND (SM): Brown, moist, medium dense; fine to coarse-grained sand, non-plastic fines, scattered fine tocoarse gravel 3 2 1 0 Notes:1.) Boring drilled to 3.0'.2.) No seepage or groundwater encountered.3.) Boring utilized for infiltration testing.4.) Excavation backfilled with cuttings and tamped on 2/26/2019. BORING LOG I-3 SPC 8505-01 Site Location:16655 Valley Boulevard, Fontana, CA 92335 Start:25 Feb 19 End:25 Feb 19 Estimated Surface Elevation:1101'Total Depth:3'Water Depth:N/A Hole Diameter:8"Equipment:CME-45 / Hollow Stem Auger Logged By:PC Depth (Ft.) Sample Type BULK Field Blow Counts / Foot Moisture Content % Relative Compaction % Dry Density, Pcf Saturation % Graphic Log Description Boring Location: At far south side of site, see Geotechnical Map, Plate 3. Project/Client:Valley Boulevard / AutoFit Inc. 1Sheet:of 1 Plate A-11 APPENDIX C SPC (2019) LABORATORY TEST RESULTS Tested By:OHF/GEB Date:06/21/22 Checked By:J. Ward Date:06/22/22 Depth (ft.): Dry Wt. of Soil + Cont. (g) Wt. of Container No. (g) Dry Wt. of Soil (g) Weight Soil Retained on #4 Sieve Percent Passing # 4 SPECIMEN INUNDATION in distilled water for the period of 24 h or expansion rate < 0.0002 in./h 875 Expansion Index (EI meas) = ((Final Rdg - Initial Rdg) / Initial Thick.) x 1000 2 1.0 0.5055 06/22/22 7:46 1.0 986 0.5055 06/22/22 5:55 1.0 Add Distilled Water to the Specimen 06/21/22 17:12 1.0 112 0.5045 10 06/21/22 15:10 1.0 0 0.5045 0.504006/21/22 15:20 Degree of Saturation (%) [ S meas]48.8 80.0 Date Time Pressure (psi) Elapsed Time (min.) Dial Readings (in.) Total Porosity 0.349 0.350 Pore Volume (cc) 72.2 72.5 Dry Density (pcf) 109.7 109.6 Void Ratio 0.536 0.538 Moisture Content (%) 9.70 15.94 Wet Density (pcf) 120.4 127.1 Dry Wt. of Soil + Cont. (g)733.30 561.81 Wt. of Container (g)0.00 198.00 Container No.OO Wet Wt. of Soil + Cont. (g)804.40 619.80 Wt. of Mold (g)198.00 0.00 Specific Gravity (Assumed) 2.70 2.70 Specimen Height (in.) 1.0000 1.0010 Wt. Comp. Soil + Mold (g)597.10 421.80 Specimen Diameter (in.) 4.01 4.01 100.00 MOLDED SPECIMEN Before Test After Test 1000.00 0.00 1000.00 0.00 FG Sample No.:B-1 Soil Identification:Olive poorly-graded sand with silt (SP-SM) Project No.:13584.001 Boring No.: EXPANSION INDEX of SOILS ASTM D 4829 Project Name: N/A JPL Fontana Project Name:JPL Fontana Tested By :G. Berdy Date:06/14/22 Project No. :13584.001 Checked By:J. Ward Date:06/17/22 Boring No.N/A Sample No.B-1 Sample Depth (ft)FG 0.00 0.00 1.00 0.00 100.61 303, 63 9 860 10:00/10:45 45 22.4956 22.4938 0.0018 74.07 74 ml of Extract For Titration (B)15 ml of AgNO3 Soln. Used in Titration (C)1.5 PPM of Chloride (C -0.2) * 100 * 30 / B 260 PPM of Chloride, Dry Wt. Basis 260 6.66 21.7 Weight of Soaked Soil (g) Moisture Content (%) CHLORIDE CONTENT, DOT California Test 422 Wt. of Crucible (g) PPM of Sulfate, Dry Weight Basis Time In / Time Out Wt. of Residue (g) (A) PPM of Sulfate (A) x 41150 Beaker No. Dry Weight of Soil + Container (g) Olive SP-SM Wet Weight of Soil + Container (g) Temperature °C pH Value Duration of Combustion (min) Soil Identification: pH TEST, DOT California Test 643 Furnace Temperature (°C) Weight of Container (g) Crucible No. Wt. of Crucible + Residue (g) TESTS for SULFATE CONTENT CHLORIDE CONTENT and pH of SOILS SULFATE CONTENT, DOT California Test 417, Part II Project Name: Tested By : Date: Project No. : Checked By: J. Ward Date: Boring No.: Depth (ft.) : Sample No. : B-1 Container No. Initial Soil Wt. (g) (Wt) Box Constant Olive SP-SM Resistance Reading (ohm) 30.70 Soil Resistivity (ohm-cm) JPL Fontana 06/17/22 06/17/22 FG 13584.001 N/A A. Santos SOIL RESISTIVITY TEST DOT CA TEST 643 Temp. (°C)pH Soil pH 4500 4650 0.00 1.00 MC =(((1+Mci/100)x(Wa/Wt+1))-1)x100 4440 32.5 74 260 6.66 21.7 4 40 50 130.303465038.37 4500 Min. Resistivity DOT CA Test 643DOT CA Test 417 Part II DOT CA Test 422 (%) (ppm) (ppm) DOT CA Test 643 1.000 Chloride Content (ohm-cm) Moisture Content Sulfate Content 5 1 2 Water Added (ml) (Wa) 30 Adjusted Moisture Content (MC)Dry Wt. of Soil + Cont. (g) 5600 Soil Identification:* *California Test 643 requires soil specimens to consist only of portions of samples passing through the No. 8 US Standard Sieve before resistivity testing. Therefore, this test method may not be representative for coarser materials. Wt. of Container (g)23.02 5600 0.00 0.00 Moisture Content (%) (MCi) Wet Wt. of Soil + Cont. (g)Specimen No. 4200 4400 4600 4800 5000 5200 5400 5600 5800 20.0 25.0 30.0 35.0 40.0 So i l R e s i s t i v i t y ( o h m - c m ) Moisture Content (%) SPC 8505-01 Page B-3 March 27, 2019 SPC Geotechnical, Inc. COMPACTION TEST (ASTM D 1557) Representative soil samples were collected in the field and tested in the laboratory to determine the maximum dry density and optimum moisture content that can be achieved under the ASTM D 1557 Compaction Test Method, Procedure B. This method requires 25 blows of a 10-pound hammer free falling from a height of 18 inches on each of the five soil layers in a 1/30-cubic foot mold. The results of the tests are presented below: DIRECT SHEAR TEST (ASTM D 3080) The direct shear test is a measure of the soil strength and was performed on remolded ring samples. The test is performed in a shear machine that operates at a constant rate of strain. Prior to testing, the soil sample was soaked for a 24-hour period. Following the test, the angle of internal friction and the cohesion intercept were evaluated for both the peak strength and residual strength, based on the resistance of the soil particles to slide past each other during testing. The shear testing results are presented on Plate B-1. Excavation No. B-2 B-3 Depth (Ft): 0.5-3 0.5-3.5 Soil Type: Silty SAND with Gravel (SM) Silty SAND (SM) Oversize-Corrected Maximum Dry Density (Pcf): 132.0 129.0 Oversize-Corrected Optimum Moisture Content (%): 8.0 8.5 Excavation No.:B-3 Depth (Ft): 0.5-3.5 Soil Type: Silty SAND (SM) Remolded to 90% Strength Type: Peak Residual C (Pcf): 100 50  (o): 32 32 Pre-Test TestPeak 100 32 Residual 50 32 DIRECT SHEAR DIAGRAM Plate B-1 SPC 8505-01 March 2019 Moisture Content (%) B-3 0.5 - 3.5 Fill (SM) - Remolded to 90% RC 9.0 14.7 Excav. No. Depth (Ft.)Sample Description Type C (Psf) (Deg) 0 1000 2000 3000 4000 5000 6000 7000 0 1000 2000 3000 4000 5000 6000 SH E A R S T R E N G T H ( P S F ) NORMAL PRESSURE (PSF) Peak Residual (12% Strain) SPC Geotechnical, Inc. In Situ Test CONSOLIDATION - PRESSURE CURVE Plate B-2 SPC 8505-01 March 2019 Excav. No. Depth (Ft.)Sample Description Moisture Content (%) B-2 7.0 Alluvium (SW) - Undisturbed, saturated at 2 Ksf 2.9 15.9 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.00.1 1.0 10.0 CO N S O L I D A T I O N ( % ) NORMAL PRESSURE (KSF) Water Added In Situ Test CONSOLIDATION - PRESSURE CURVE Plate B-3 SPC 8505-01 March 2019 Excav. No. Depth (Ft.)Sample Description Moisture Content (%) B-6 6.0 Alluvium (SM) - Undisturbed, saturated at 2 Ksf 7.1 18.2 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.00.1 1.0 10.0 CO N S O L I D A T I O N ( % ) NORMAL PRESSURE (KSF) Water Added APPENDIX D SEISMIC 6/15/22, 11:59 AM U.S. Seismic Design Maps https://seismicmaps.org 1/2 Latitude, Longitude: 34.0694, -117.4416 Date 6/15/2022, 12:00:01 PM Design Code Reference Document ASCE7-16 Risk Category II Site Class D - Stiff Soil Type Value Description SS 1.813 MCER ground motion. (for 0.2 second period) S1 0.6 MCER ground motion. (for 1.0s period) SMS 1.813 Site-modified spectral acceleration value SM1 null -See Section 11.4.8 Site-modified spectral acceleration value SDS 1.209 Numeric seismic design value at 0.2 second SA SD1 null -See Section 11.4.8 Numeric seismic design value at 1.0 second SA Type Value Description SDC null -See Section 11.4.8 Seismic design category Fa 1 Site amplification factor at 0.2 second Fv null -See Section 11.4.8 Site amplification factor at 1.0 second PGA 0.74 MCEG peak ground acceleration FPGA 1.1 Site amplification factor at PGA PGAM 0.814 Site modified peak ground acceleration TL 12 Long-period transition period in seconds SsRT 1.881 Probabilistic risk-targeted ground motion. (0.2 second) SsUH 2.021 Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration SsD 1.813 Factored deterministic acceleration value. (0.2 second) S1RT 0.709 Probabilistic risk-targeted ground motion. (1.0 second) S1UH 0.783 Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration. S1D 0.6 Factored deterministic acceleration value. (1.0 second) PGAd 0.74 Factored deterministic acceleration value. (Peak Ground Acceleration) CRS 0.931 Mapped value of the risk coefficient at short periods CR1 0.906 Mapped value of the risk coefficient at a period of 1 s 6/15/22, 11:59 AM U.S. Seismic Design Maps https://seismicmaps.org 2/2 DISCLAIMER While the information presented on this website is believed to be correct, SEAOC /OSHPD and its sponsors and contributors assume no responsibility or liability for its accuracy. The material presented in this web application should not be used or relied upon for any specific application without competent examination and verification of its accuracy, suitability and applicability by engineers or other licensed professionals. SEAOC / OSHPD do not intend that the use of this information replace the sound judgment of such competent professionals, having experience and knowledge in the field of practice, nor to substitute for the standard of care required of such professionals in interpreting and applying the results of the seismic data provided by this website. Users of the information from this website assume all liability arising from such use. Use of the output of this website does not imply approval by the governing building code bodies responsible for building code approval and interpretation for the building site described by latitude/longitude location in the search results of this website. Unied Hazard Tool Input U.S. Geological Survey - Earthquake Hazards Program Please do not use this tool to obtain ground motion parameter values for the design code reference documents covered by the U.S. Seismic Design Maps web tools (e.g., the International Building Code and the ASCE 7 or 41 Standard). The values returned by the two applications are not identical.  Edition Dynamic: Conterminous U.S. 2014 (u… Latitude Decimal degrees 34.0694 Longitude Decimal degrees, negative values for western longitudes -117.4416 Site Class 259 m/s (Site class D) Spectral Period Peak Ground Acceleration Time Horizon Return period in years 2475 Hazard Curve View Raw Data Hazard Curves Time Horizon 2475 years Peak Ground Acceleration 0.10 Second Spectral Acceleration0.20 Second Spectral Acceleration0.30 Second Spectral Acceleration0.50 Second Spectral Acceleration0.75 Second Spectral Acceleration 1.00 Second Spectral Acceleration2.00 Second Spectral Acceleration3.00 Second Spectral Acceleration4.00 Second Spectral Acceleration5.00 Second Spectral Acceleration 1e-2 1e-1 1e+0 Ground Motion (g) 1e-9 1e-8 1e-7 1e-6 1e-5 1e-4 1e-3 1e-2 1e-1 1e+0 Annual Frequency of Exceedence Uniform Hazard Response Spectrum 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Spectral Period (s) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Ground Motion (g) Spectral Period (s): PGAGround Motion (g): 0.8521 Component Curves for Peak Ground Acceleration Time Horizon 2475 yearsSystemGridInterface Fault 1e-2 1e-1 1e+0 Ground Motion (g) 1e-10 1e-9 1e-8 1e-7 1e-6 1e-5 1e-4 1e-3 1e-2 1e-1 1e+0 Annual Frequency of Exceedence Deaggregation Component Total ε = (-∞ .. -2.5) ε = [-2.5 .. -2) ε = [-2 .. -1.5) ε = [-1.5 .. -1) ε = [-1 .. -0.5) ε = [-0.5 .. 0) ε = [0 .. 0.5) ε = [0.5 .. 1) ε = [1 .. 1.5) ε = [1.5 .. 2) ε = [2 .. 2.5) ε = [2.5 .. +∞) 5 15 25 35 Closest Distance, rRup (km) 45 55 65 75 98.5 87.5 M a g n it u d e (M w ) 76.5 65.5 54.5 5 10 % Contribution to Hazard 15 20 25 5 15 25 35 45 Closest Distance, rRup (km)55 65 75 9 8.5 8 7.57 6 .5 M a g n it u d e (M w ) 6 5 .55 4.5 Summary statistics for, Deaggregation: Total Deaggregation targets Return period:2475 yrs Exceedance rate:0.0004040404 yr⁻¹ PGA ground motion:0.85210267 g Recovered targets Return period:3177.3278 yrs Exceedance rate:0.00031472988 yr⁻¹ Totals Binned:100 % Residual:0 % Trace:0.03 % Mean (over all sources) m:7.09 r:11.85 km ε₀:1.76 σ Mode (largest m-r bin) m:8.1 r:13.28 km ε₀:1.54 σ Contribution:17.93 % Mode (largest m-r-ε₀ bin) m:7.91 r:16.15 km ε₀:1.78 σ Contribution:9.05 % Discretization r:min = 0.0, max = 1000.0, Δ = 20.0 km m:min = 4.4, max = 9.4, Δ = 0.2 ε:min = -3.0, max = 3.0, Δ = 0.5 σ Epsilon keys ε0:[-∞ .. -2.5) ε1:[-2.5 .. -2.0) ε2:[-2.0 .. -1.5) ε3:[-1.5 .. -1.0) ε4:[-1.0 .. -0.5) ε5:[-0.5 .. 0.0) ε6:[0.0 .. 0.5) ε7:[0.5 .. 1.0) ε8:[1.0 .. 1.5) ε9:[1.5 .. 2.0) ε10:[2.0 .. 2.5) ε11:[2.5 .. +∞] Deaggregation Contributors Source Set  Source Type r m ε0 lon lat az % UC33brAvg_FM31 System 34.13 San Jacinto (San Bernardino) [3]11.09 8.04 1.47 117.338°W 34.120°N 59.42 11.44 San Andreas (San Bernardino N) [3]17.98 7.86 1.89 117.341°W 34.208°N 30.81 9.82 Fontana (Seismicity) [0]4.09 6.61 1.33 117.470°W 34.094°N 316.11 4.13 San Jacinto (Lytle Creek connector) [2]9.68 8.00 1.38 117.374°W 34.134°N 41.05 3.48 Cucamonga [0]12.70 7.42 1.77 117.480°W 34.178°N 343.58 1.26 UC33brAvg_FM32 System 33.31 San Jacinto (San Bernardino) [3]11.09 8.03 1.47 117.338°W 34.120°N 59.42 11.35 San Andreas (San Bernardino N) [3]17.98 7.86 1.89 117.341°W 34.208°N 30.81 9.98 San Jacinto (Lytle Creek connector) [2]9.68 7.99 1.38 117.374°W 34.134°N 41.05 3.50 Fontana (Seismicity) [0]4.09 6.61 1.33 117.470°W 34.094°N 316.11 3.38 Cucamonga [0]12.70 7.44 1.76 117.480°W 34.178°N 343.58 1.19 UC33brAvg_FM31 (opt)Grid 16.29 PointSourceFinite: -117.442, 34.119 7.47 5.64 1.87 117.442°W 34.119°N 0.00 3.52 PointSourceFinite: -117.442, 34.119 7.47 5.64 1.87 117.442°W 34.119°N 0.00 3.52 PointSourceFinite: -117.442, 34.128 8.10 5.67 1.95 117.442°W 34.128°N 0.00 1.71 PointSourceFinite: -117.442, 34.128 8.10 5.67 1.95 117.442°W 34.128°N 0.00 1.71 PointSourceFinite: -117.442, 34.146 9.11 5.88 2.01 117.442°W 34.146°N 0.00 1.27 PointSourceFinite: -117.442, 34.146 9.11 5.88 2.01 117.442°W 34.146°N 0.00 1.27 UC33brAvg_FM32 (opt)Grid 16.26 PointSourceFinite: -117.442, 34.119 7.47 5.64 1.87 117.442°W 34.119°N 0.00 3.52 PointSourceFinite: -117.442, 34.119 7.47 5.64 1.87 117.442°W 34.119°N 0.00 3.52 PointSourceFinite: -117.442, 34.128 8.10 5.67 1.95 117.442°W 34.128°N 0.00 1.71 PointSourceFinite: -117.442, 34.128 8.10 5.67 1.95 117.442°W 34.128°N 0.00 1.71 PointSourceFinite: -117.442, 34.146 9.11 5.88 2.01 117.442°W 34.146°N 0.00 1.27 PointSourceFinite: -117.442, 34.146 9.11 5.88 2.01 117.442°W 34.146°N 0.00 1.27 Liquefaction Susceptibility Analysis: SPT Method Leighton Youd and Idriss (2001), Martin and Lew (1999) Description: JPI Fontana; Case 1; PGAm 0.81; design GW 268; No overex 0 Project No.: 13584.001 Jun 2022 General Boring Information: Existing Design Design Overex. Ground design Boring Location General Parameters: Boring GW GW Fill Height depth bgs Surface gw Coordinates amax = 0.81g No. Depth (ft) Depth (ft) (ft) (ft) Elev (ft)elve X (ft) Y (ft)MW = 8.1 B-2 268 268 0 1112 844 188 -108 MSF eq: 1 B-3 268 268 0 1106 838 692 -516 MSF = 0.82 B-4 268 268 0 1113 845 697 -96 Hammer Efficiency =84 B-5 268 268 0 1109 841 336 -298 CE = 1.40 B-7 268 268 0 1106 838 221 -521 CB = 1 0 CS for SPT? TRUE 0 Unlined, but room for liner 0 Rod Stickup (feet) =3 0 Ring sample correction =0.65 0 0 0 0 0 0 0 0 Leighton Page 1 of 1 Summary of Liquefaction Susceptibility Analysis: SPT Method Leighton Liquefaction Method: Youd and Idriss (2001). Seismic Settlement Method: Tokimatsu and Seed (1987) and Martin and Lew (1999). Project: JPI Fontana; Case 1; PGAm 0.81; design GW 268; No overex 0 Project No.: 13584.001 Boring No. Approx. Layer Depth SPT Depth Approx Layer Thick- ness Plasticity ("n"=non susc. to liq.) Estimated Fines Cont t Nm or B Sampler Type (enter 2 if mod CA Ring)Cs Nm (corrected for Cs and ring->SPT) Exist vo'(N1)60 (N1)60CS CRR7.5 Design vo' CSR7.5 CSRM Liquefaction Factor of Safety (N1)60CS (for Settle- ment) Dry Sand Strain (%) (Tok/ Seed 87) Sat Sand Strain (%) (Tok/ Seed 87) Seismic Sett. of Layer Cummulative Seismic Settlement (ft) (ft) (ft) (%) (pcf)(blows/ft)(blows/ft) (psf) (psf) (blows/ft) (%) (%) (in.) (in.) B-2 0 to 4.5 3 4.5 5 120 46 2 1 29.9 360 53.4 53.4 >Range 360 0.52 0.64 NonLiq 53.4 0.02 0.01 0.7 B-2 4.5 to 8.0 6 3.5 5 120 20 2 1 13.0 720 23.2 23.2 0.260 720 0.52 0.63 NonLiq 23.2 0.37 0.16 0.6 B-2 8.0 to 12.5 10 4.5 5 120 36 2 1 23.4 1200 36.7 36.7 >Range 1200 0.51 0.63 NonLiq 36.7 0.28 0.15 0.5 B-2 12.5 to 17.5 15 5.0 5 120 62 2 1 40.3 1800 51.7 51.7 >Range 1800 0.51 0.62 NonLiq 51.7 0.04 0.02 0.3 B-2 17.5 to 22.5 20 5.0 5 120 68 2 1 44.2 2400 54.8 54.8 >Range 2400 0.50 0.61 NonLiq 54.8 0.05 0.03 0.3 B-2 22.5 to 27.5 25 5.0 5 120 100 2 1 65.0 3000 72.1 72.1 >Range 3000 0.50 0.60 NonLiq 72.1 0.06 0.03 0.3 B-2 27.5 to 32.0 30 4.5 10 120 39 2 1 25.4 3600 27.0 28.5 0.388 3600 0.49 0.60 NonLiq 28.5 0.47 0.25 0.3 B-3 0 to 4.0 3 4.0 10 120 12 2 1 7.8 360 13.9 15.1 0.161 360 0.52 0.64 NonLiq 15.1 1.03 0.49 3.9 B-3 4.0 to 7.5 5 3.5 10 120 15 2 1 9.8 600 17.4 18.6 0.199 600 0.52 0.63 NonLiq 18.6 1.50 0.63 3.4 B-3 7.5 to 12.5 10 5.0 25 120 18 2 1 11.7 1200 18.4 24.8 0.287 1200 0.51 0.63 NonLiq 24.8 0.70 0.42 2.8 B-3 12.5 to 17.5 15 5.0 5 120 40 2 1 26.0 1800 33.3 33.3 >Range 1800 0.51 0.62 NonLiq 33.3 0.18 0.11 2.4 B-3 17.5 to 22.5 20 5.0 10 120 19 2 1 12.4 2400 15.3 16.5 0.176 2400 0.50 0.61 NonLiq 16.5 1.49 0.89 2.3 B-3 22.5 to 27.5 25 5.0 25 120 18 2 1 11.7 3000 13.0 18.8 0.201 3000 0.50 0.60 NonLiq 18.8 1.61 0.97 1.4 B-3 27.5 to 32.0 30 4.5 25 120 21 2 1 13.7 3600 14.6 20.5 0.222 3600 0.49 0.60 NonLiq 20.5 0.75 0.40 0.4 B-4 0 to 4.0 3 4.0 5 120 22 2 1 14.3 360 25.5 25.5 0.303 360 0.52 0.64 NonLiq 25.5 0.32 0.15 1.4 B-4 4.0 to 7.5 5 3.5 5 120 19 2 1 12.4 600 22.0 22.0 0.243 600 0.52 0.63 NonLiq 22.0 0.95 0.40 1.3 B-4 7.5 to 12.5 10 5.0 25 120 15 2 1 9.8 1200 15.3 21.4 0.233 1200 0.51 0.63 NonLiq 21.4 0.81 0.48 0.9 B-4 12.5 to 17.5 15 5.0 25 120 46 2 1 29.9 1800 38.3 47.0 >Range 1800 0.51 0.62 NonLiq 47.0 0.04 0.02 0.4 B-4 17.5 to 22.5 20 5.0 25 120 58 2 1 37.7 2400 46.8 56.4 >Range 2400 0.50 0.61 NonLiq 56.4 0.05 0.03 0.4 B-4 22.5 to 27.5 25 5.0 5 120 73 2 1 47.5 3000 52.6 52.6 >Range 3000 0.50 0.60 NonLiq 52.6 0.09 0.05 0.3 B-4 27.5 to 32.0 30 4.5 25 120 28 2 1 18.2 3600 19.4 25.9 0.311 3600 0.49 0.60 NonLiq 25.9 0.52 0.28 0.3 B-5 0 to 7.5 5 7.5 10 120 28 2 1 18.2 600 32.5 34.1 >Range 600 0.52 0.63 NonLiq 34.1 0.34 0.31 1.1 B-5 7.5 to 12.5 10 5.0 5 120 26 2 1 16.9 1200 26.5 26.5 0.326 1200 0.51 0.63 NonLiq 26.5 0.65 0.39 0.8 B-5 12.5 to 17.5 15 5.0 25 120 20 2 1 13.0 1800 16.7 22.9 0.255 1800 0.51 0.62 NonLiq 22.9 0.56 0.34 0.4 B-5 17.5 to 22.0 20 4.5 5 120 68 2 1 44.2 2400 54.8 54.8 >Range 2400 0.50 0.61 NonLiq 54.8 0.05 0.03 0.0 B-7 0 to 4.5 3 4.5 25 120 16 2 1 10.4 360 18.6 25.0 0.292 360 0.52 0.64 NonLiq 25.0 0.34 0.18 1.9 B-7 4.5 to 8.0 6 3.5 5 120 14 2 1 9.1 720 16.2 16.2 0.173 720 0.52 0.63 NonLiq 16.2 0.86 0.36 1.7 B-7 8.0 to 12.5 10 4.5 25 120 17 2 1 11.1 1200 17.3 23.6 0.267 1200 0.51 0.63 NonLiq 23.6 0.73 0.39 1.3 B-7 12.5 to 17.5 15 5.0 25 120 32 2 1 20.8 1800 26.7 34.0 >Range 1800 0.51 0.62 NonLiq 34.0 0.18 0.11 1.0 B-7 17.5 to 22.5 20 5.0 25 120 70 2 1 45.5 2400 56.4 67.2 >Range 2400 0.50 0.61 NonLiq 67.2 0.04 0.03 0.8 B-7 22.5 to 27.5 25 5.0 5 120 40 2 1 26.0 3000 28.8 28.8 0.403 3000 0.50 0.60 NonLiq 28.8 0.92 0.55 0.8 B-7 27.5 to 32.0 30 4.5 60 120 26 2 1 16.9 3600 18.0 26.6 0.328 3600 0.49 0.60 NonLiq 26.6 0.51 0.27 0.3 Leighton Page 1 of 1 Liquefaction Susceptibility Analysis: SPT Method Leighton Youd and Idriss (2001), Martin and Lew (1999) Description: JPI Fontana; Case 4; PGAm 0.81; existing GW 322; Overex. 8 Project No.: 13584.001 Jun 2022 General Boring Information: Existing Design Design Overex. Ground design Boring Location General Parameters: Boring GW GW Fill Height depth bgs Surface gw Coordinates amax = 0.81g No. Depth (ft) Depth (ft) (ft) (ft) Elev (ft)elve X (ft) Y (ft)MW = 8.1 B-2 268 322 8 1112 790 188 -108 MSF eq: 1 B-3 268 322 8 1106 784 692 -516 MSF = 0.82 B-4 268 322 8 1113 791 697 -96 Hammer Efficiency =84 B-5 268 322 8 1109 787 336 -298 CE = 1.40 B-7 268 322 8 1106 784 221 -521 CB = 1 0 CS for SPT? TRUE 0 Unlined, but room for liner 0 Rod Stickup (feet) =3 0 Ring sample correction =0.65 0 0 0 0 0 0 0 0 Leighton Page 1 of 1 Summary of Liquefaction Susceptibility Analysis: SPT Method Leighton Liquefaction Method: Youd and Idriss (2001). Seismic Settlement Method: Tokimatsu and Seed (1987) and Martin and Lew (1999). Project: JPI Fontana; Case 4; PGAm 0.81; existing GW 322; Overex. 8 Project No.: 13584.001 Boring No. Approx. Layer Depth SPT Depth Approx Layer Thick- ness Plasticity ("n"=non susc. to liq.) Estimated Fines Cont t Nm or B Sampler Type (enter 2 if mod CA Ring)Cs Nm (corrected for Cs and ring->SPT) Exist vo'(N1)60 (N1)60CS CRR7.5 Design vo' CSR7.5 CSRM Liquefaction Factor of Safety (N1)60CS (for Settle- ment) Dry Sand Strain (%) (Tok/ Seed 87) Sat Sand Strain (%) (Tok/ Seed 87) Seismic Sett. of Layer Cummulative Seismic Settlement (ft) (ft) (ft) (%) (pcf)(blows/ft)(blows/ft) (psf) (psf) (blows/ft) (%) (%) (in.) (in.) B-2 0 to 4.5 3 4.5 OX 5 120 50 1 1.3 65.0 360 116.0 116.0 >Range 360 0.52 0.64 NonLiq 116.0 0.00 0.00 0.5 B-2 4.5 to 8.0 6 3.5 OX 5 120 50 1 1.3 65.0 720 116.0 116.0 >Range 720 0.52 0.63 NonLiq 116.0 0.00 0.00 0.5 B-2 8.0 to 12.5 10 4.5 5 120 36 2 1 23.4 1200 36.7 36.7 >Range 1200 0.51 0.63 NonLiq 36.7 0.28 0.15 0.5 B-2 12.5 to 17.5 15 5.0 5 120 62 2 1 40.3 1800 51.7 51.7 >Range 1800 0.51 0.62 NonLiq 51.7 0.04 0.02 0.3 B-2 17.5 to 22.5 20 5.0 5 120 68 2 1 44.2 2400 54.8 54.8 >Range 2400 0.50 0.61 NonLiq 54.8 0.05 0.03 0.3 B-2 22.5 to 27.5 25 5.0 5 120 100 2 1 65.0 3000 72.1 72.1 >Range 3000 0.50 0.60 NonLiq 72.1 0.06 0.03 0.3 B-2 27.5 to 32.0 30 4.5 10 120 39 2 1 25.4 3600 27.0 28.5 0.388 3600 0.49 0.60 NonLiq 28.5 0.47 0.25 0.3 B-3 0 to 4.0 3 4.0 OX 10 120 50 1 1.3 65.0 360 116.0 119.4 >Range 360 0.52 0.64 NonLiq 119.4 0.00 0.00 2.8 B-3 4.0 to 7.5 5 3.5 OX 10 120 50 1 1.3 65.0 600 116.0 119.4 >Range 600 0.52 0.63 NonLiq 119.4 0.00 0.00 2.8 B-3 7.5 to 8.0 10 0.5 OX 25 120 50 1 1.3 65.0 1200 102.0 118.1 >Range 1200 0.510.63 NonLiq 118.1 0.00 0.00 2.8 B-3 8.0 to 12.5 10 4.5 25 120 18 2 1 11.7 1200 18.4 24.8 0.287 1200 0.51 0.63 NonLiq 24.8 0.70 0.38 2.8 B-3 12.5 to 17.5 15 5.0 5 120 40 2 1 26.0 1800 33.3 33.3 >Range 1800 0.51 0.62 NonLiq 33.3 0.18 0.11 2.4 B-3 17.5 to 22.5 20 5.0 10 120 19 2 1 12.4 2400 15.3 16.5 0.176 2400 0.50 0.61 NonLiq 16.5 1.49 0.89 2.3 B-3 22.5 to 27.5 25 5.0 25 120 18 2 1 11.7 3000 13.0 18.8 0.201 3000 0.50 0.60 NonLiq 18.8 1.61 0.97 1.4 B-3 27.5 to 32.0 30 4.5 25 120 21 2 1 13.7 3600 14.6 20.5 0.222 3600 0.49 0.60 NonLiq 20.5 0.75 0.40 0.4 B-4 0 to 4.0 3 4.0 OX 5 120 50 1 1.3 65.0 360 116.0 116.0 >Range 360 0.52 0.64 NonLiq 116.0 0.00 0.00 0.8 B-4 4.0 to 7.5 5 3.5 OX 5 120 50 1 1.3 65.0 600 116.0 116.0 >Range 600 0.52 0.63 NonLiq 116.0 0.00 0.00 0.8 B-4 7.5 to 8.0 10 0.5 OX 25 120 50 1 1.3 65.0 1200 102.0 118.1 >Range 1200 0.510.63 NonLiq 118.1 0.00 0.00 0.8 B-4 8.0 to 12.5 10 4.5 25 120 15 2 1 9.8 1200 15.3 21.4 0.233 1200 0.51 0.63 NonLiq 21.4 0.81 0.44 0.8 B-4 12.5 to 17.5 15 5.0 25 120 46 2 1 29.9 1800 38.3 47.0 >Range 1800 0.51 0.62 NonLiq 47.0 0.04 0.02 0.4 B-4 17.5 to 22.5 20 5.0 25 120 58 2 1 37.7 2400 46.8 56.4 >Range 2400 0.50 0.61 NonLiq 56.4 0.05 0.03 0.4 B-4 22.5 to 27.5 25 5.0 5 120 73 2 1 47.5 3000 52.6 52.6 >Range 3000 0.50 0.60 NonLiq 52.6 0.09 0.05 0.3 B-4 27.5 to 32.0 30 4.5 25 120 28 2 1 18.2 3600 19.4 25.9 0.311 3600 0.49 0.60 NonLiq 25.9 0.52 0.28 0.3 B-5 0 to 7.5 5 7.5 OX 10 120 50 1 1.3 65.0 600 116.0 119.4 >Range 600 0.52 0.63 NonLiq 119.4 0.00 0.00 0.7 B-5 7.5 to 8.0 10 0.5 OX 5 120 50 1 1.3 65.0 1200 102.0 102.0 >Range 1200 0.51 0.63 NonLiq 102.0 0.00 0.00 0.7 B-5 8.0 to 12.5 10 4.5 5 120 26 2 1 16.9 1200 26.5 26.5 0.326 1200 0.51 0.63 NonLiq 26.5 0.65 0.35 0.7 B-5 12.5 to 17.5 15 5.0 25 120 20 2 1 13.0 1800 16.7 22.9 0.255 1800 0.51 0.62 NonLiq 22.9 0.56 0.34 0.4 B-5 17.5 to 22.0 20 4.5 5 120 68 2 1 44.2 2400 54.8 54.8 >Range 2400 0.50 0.61 NonLiq 54.8 0.05 0.03 0.0 B-7 0 to 4.5 3 4.5 OX 25 120 50 1 1.3 65.0 360 116.0 133.7 >Range 360 0.52 0.64 NonLiq 133.7 0.00 0.00 1.3 B-7 4.5 to 8.0 6 3.5 OX 5 120 50 1 1.3 65.0 720 116.0 116.0 >Range 720 0.52 0.63 NonLiq 116.0 0.00 0.00 1.3 B-7 8.0 to 12.5 10 4.5 25 120 17 2 1 11.1 1200 17.3 23.6 0.267 1200 0.51 0.63 NonLiq 23.6 0.73 0.39 1.3 B-7 12.5 to 17.5 15 5.0 25 120 32 2 1 20.8 1800 26.7 34.0 >Range 1800 0.51 0.62 NonLiq 34.0 0.18 0.11 1.0 B-7 17.5 to 22.5 20 5.0 25 120 70 2 1 45.5 2400 56.4 67.2 >Range 2400 0.50 0.61 NonLiq 67.2 0.04 0.03 0.8 Leighton Page 1 of 2 Boring No. Approx. Layer Depth SPT Depth Approx Layer Thick- ness Plasticity ("n"=non susc. to liq.) Estimated Fines Cont t Nm or B Sampler Type (enter 2 if mod CA Ring)Cs Nm (corrected for Cs and ring->SPT) Exist vo'(N1)60 (N1)60CS CRR7.5 Design vo' CSR7.5 CSRM Liquefaction Factor of Safety (N1)60CS (for Settle- ment) Dry Sand Strain (%) (Tok/ Seed 87) Sat Sand Strain (%) (Tok/ Seed 87) Seismic Sett. of Layer Cummulative Seismic Settlement (ft) (ft) (ft) (%) (pcf)(blows/ft)(blows/ft) (psf) (psf) (blows/ft) (%) (%) (in.) (in.) B-7 22.5 to 27.5 25 5.0 5 120 40 2 1 26.0 3000 28.8 28.8 0.403 3000 0.50 0.60 NonLiq 28.8 0.92 0.55 0.8 B-7 27.5 to 32.0 30 4.5 60 120 26 2 1 16.9 3600 18.0 26.6 0.328 3600 0.49 0.60 NonLiq 26.6 0.51 0.27 0.3 Leighton Page 2 of 2 APPENDIX E GENERAL EARTHWORK AND GRADING SPECIFICATIONS 1 3030.495 LEIGHTON AND ASSOCIATES, INC. GENERAL EARTHWORK AND GRADING SPECIFICATIONS FOR ROUGH GRADING Table of Contents Section Page 1.0 GENERAL 1 1.1 Intent 1 1.2 The Geotechnical Consultant of Record 1 1.3 The Earthwork Contractor 2 2.0 PREPARATION OF AREAS TO BE FILLED 2 2.1 Clearing and Grubbing 2 2.2 Processing 3 2.3 Overexcavation 3 2.4 Benching 3 2.5 Evaluation/Acceptance of Fill Areas 3 3.0 FILL MATERIAL 4 3.1 General 4 3.2 Oversize 4 3.3 Import 4 4.0 FILL PLACEMENT AND COMPACTION 4 4.1 Fill Layers 4 4.2 Fill Moisture Conditioning 4 4.3 Compaction of Fill 5 4.4 Compaction of Fill Slopes 5 4.5 Compaction Testing 5 4.6 Frequency of Compaction Testing 5 4.7 Compaction Test Locations 5 5.0 SUBDRAIN INSTALLATION 6 6.0 EXCAVATION 6 7.0 TRENCH BACKFILLS 6 7.1 Safety 6 7.2 Bedding and Backfill 6 7.3 Lift Thickness 6 7.4 Observation and Testing 6 1 3030.495 LEIGHTON AND ASSOCIATES, INC. General Earthwork and Grading Specifications 1.0 General 1.1 Intent: These General Earthwork and Grading Specifications are for the grading and earthwork shown on the approved grading plan(s) and/or indicated in the geotechnical report(s). These Specifications are a part of the recommendations contained in the geotechnical report(s). In case of conflict, the specific recommendations in the geotechnical report shall supersede these more general Specifications. Observations of the earthwork by the project Geotechnical Consultant during the course of grading may result in new or revised recommendations that could supersede these specifications or the recommendations in the geotechnical report(s). 1.2 The Geotechnical Consultant of Record: Prior to commencement of work, the owner shall employ the Geotechnical Consultant of Record (Geotechnical Consultant). The Geotechnical Consultants shall be responsible for reviewing the approved geotechnical report(s) and accepting the adequacy of the preliminary geotechnical findings, conclusions, and recommendations prior to the commencement of the grading. Prior to commencement of grading, the Geotechnical Consultant shall review the "work plan" prepared by the Earthwork Contractor (Contractor) and schedule sufficient personnel to perform the appropriate level of observation, mapping, and compaction testing. During the grading and earthwork operations, the Geotechnical Consultant shall observe, map, and document the subsurface exposures to verify the geotechnical design assumptions. If the observed conditions are found to be significantly different than the interpreted assumptions during the design phase, the Geotechnical Consultant shall inform the owner, recommend appropriate changes in design to accommodate the observed conditions, and notify the review agency where required. Subsurface areas to be geotechnically observed, mapped, elevations recorded, and/or tested include natural ground after it has been cleared for receiving fill but before fill is placed, bottoms of all "remedial removal" areas, all key bottoms, and benches made on sloping ground to receive fill. The Geotechnical Consultant shall observe the moisture-conditioning and processing of the subgrade and fill materials and perform relative compaction testing of fill to determine the attained level of compaction. The Geotechnical Consultant shall provide the test results to the owner and the Contractor on a routine and frequent basis. 2 3030.495 LEIGHTON AND ASSOCIATES, INC. General Earthwork and Grading Specifications 1.3 The Earthwork Contractor: The Earthwork Contractor (Contractor) shall be qualified, experienced, and knowledgeable in earthwork logistics, preparation and processing of ground to receive fill, moisture-conditioning and processing of fill, and compacting fill. The Contractor shall review and accept the plans, geotechnical report(s), and these Specifications prior to commencement of grading. The Contractor shall be solely responsible for performing the grading in accordance with the plans and specifications. The Contractor shall prepare and submit to the owner and the Geotechnical Consultant a work plan that indicates the sequence of earthwork grading, the number of "spreads" of work and the estimated quantities of daily earthwork contemplated for the site prior to commencement of grading. The Contractor shall inform the owner and the Geotechnical Consultant of changes in work schedules and updates to the work plan at least 24 hours in advance of such changes so that appropriate observations and tests can be planned and accomplished. The Contractor shall not assume that the Geotechnical Consultant is aware of all grading operations. The Contractor shall have the sole responsibility to provide adequate equipment and methods to accomplish the earthwork in accordance with the applicable grading codes and agency ordinances, these Specifications, and the recommendations in the approved geotechnical report(s) and grading plan(s). If, in the opinion of the Geotechnical Consultant, unsatisfactory conditions, such as unsuitable soil, improper moisture condition, inadequate compaction, insufficient buttress key size, adverse weather, etc., are resulting in a quality of work less than required in these specifications, the Geotechnical Consultant shall reject the work and may recommend to the owner that construction be stopped until the conditions are rectified. 2.0 Preparation of Areas to be Filled 2.1 Clearing and Grubbing: Vegetation, such as brush, grass, roots, and other deleterious material shall be sufficiently removed and properly disposed of in a method acceptable to the owner, governing agencies, and the Geotechnical Consultant. The Geotechnical Consultant shall evaluate the extent of these removals depending on specific site conditions. Earth fill material shall not contain more than 1 percent of organic materials (by volume). No fill lift shall contain more than 5 percent of organic matter. Nesting of the organic materials shall not be allowed. 3 3030.495 LEIGHTON AND ASSOCIATES, INC. General Earthwork and Grading Specifications If potentially hazardous materials are encountered, the Contractor shall stop work in the affected area, and a hazardous material specialist shall be informed immediately for proper evaluation and handling of these materials prior to continuing to work in that area. As presently defined by the State of California, most refined petroleum products (gasoline, diesel fuel, motor oil, grease, coolant, etc.) have chemical constituents that are considered to be hazardous waste. As such, the indiscriminate dumping or spillage of these fluids onto the ground may constitute a misdemeanor, punishable by fines and/or imprisonment, and shall not be allowed. 2.2 Processing: Existing ground that has been declared satisfactory for support of fill by the Geotechnical Consultant shall be scarified to a minimum depth of 6 inches. Existing ground that is not satisfactory shall be overexcavated as specified in the following section. Scarification shall continue until soils are broken down and free of large clay lumps or clods and the working surface is reasonably uniform, flat, and free of uneven features that would inhibit uniform compaction. 2.3 Overexcavation: In addition to removals and overexcavations recommended in the approved geotechnical report(s) and the grading plan, soft, loose, dry, saturated, spongy, organic-rich, highly fractured or otherwise unsuitable ground shall be overexcavated to competent ground as evaluated by the Geotechnical Consultant during grading. 2.4 Benching: Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical units), the ground shall be stepped or benched. Please see the Standard Details for a graphic illustration. The lowest bench or key shall be a minimum of 15 feet wide and at least 2 feet deep, into competent material as evaluated by the Geotechnical Consultant. Other benches shall be excavated a minimum height of 4 feet into competent material or as otherwise recommended by the Geotechnical Consultant. Fill placed on ground sloping flatter than 5:1 shall also be benched or otherwise overexcavated to provide a flat subgrade for the fill. 2.5 Evaluation/Acceptance of Fill Areas: All areas to receive fill, including removal and processed areas, key bottoms, and benches, shall be observed, mapped, elevations recorded, and/or tested prior to being accepted by the Geotechnical Consultant as suitable to receive fill. The Contractor shall obtain a written acceptance from the Geotechnical Consultant prior to fill placement. A licensed surveyor shall provide the survey control for determining elevations of processed areas, keys, and benches. 4 3030.495 LEIGHTON AND ASSOCIATES, INC. General Earthwork and Grading Specifications 3.0 Fill Material 3.1 General: Material to be used as fill shall be essentially free of organic matter and other deleterious substances evaluated and accepted by the Geotechnical Consultant prior to placement. Soils of poor quality, such as those with unacceptable gradation, high expansion potential, or low strength shall be placed in areas acceptable to the Geotechnical Consultant or mixed with other soils to achieve satisfactory fill material. 3.2 Oversize: Oversize material defined as rock, or other irreducible material with a maximum dimension greater than 8 inches, shall not be buried or placed in fill unless location, materials, and placement methods are specifically accepted by the Geotechnical Consultant. Placement operations shall be such that nesting of oversized material does not occur and such that oversize material is completely surrounded by compacted or densified fill. Oversize material shall not be placed within 10 vertical feet of finish grade or within 2 feet of future utilities or underground construction. 3.3 Import: If importing of fill material is required for grading, proposed import material shall meet the requirements of Section 3.1. The potential import source shall be given to the Geotechnical Consultant at least 48 hours (2 working days) before importing begins so that its suitability can be determined and appropriate tests performed. 4.0 Fill Placement and Compaction 4.1 Fill Layers: Approved fill material shall be placed in areas prepared to receive fill (per Section 3.0) in near-horizontal layers not exceeding 8 inches in loose thickness. The Geotechnical Consultant may accept thicker layers if testing indicates the grading procedures can adequately compact the thicker layers. Each layer shall be spread evenly and mixed thoroughly to attain relative uniformity of material and moisture throughout. 4.2 Fill Moisture Conditioning: Fill soils shall be watered, dried back, blended, and/or mixed, as necessary to attain a relatively uniform moisture content at or slightly over optimum. Maximum density and optimum soil moisture content tests shall be performed in accordance with the American Society of Testing and Materials (ASTM Test Method D1557-91). 5 3030.495 LEIGHTON AND ASSOCIATES, INC. General Earthwork and Grading Specifications 4.3 Compaction of Fill: After each layer has been moisture-conditioned, mixed, and evenly spread, it shall be uniformly compacted to not less than 90 percent of maximum dry density (ASTM Test Method D1557-91). Compaction equipment shall be adequately sized and be either specifically designed for soil compaction or of proven reliability to efficiently achieve the specified level of compaction with uniformity. 4.4 Compaction of Fill Slopes: In addition to normal compaction procedures specified above, compaction of slopes shall be accomplished by backrolling of slopes with sheepsfoot rollers at increments of 3 to 4 feet in fill elevation, or by other methods producing satisfactory results acceptable to the Geotechnical Consultant. Upon completion of grading, relative compaction of the fill, out to the slope face, shall be at least 90 percent of maximum density per ASTM Test Method D1557-91. 4.5 Compaction Testing: Field tests for moisture content and relative compaction of the fill soils shall be performed by the Geotechnical Consultant. Location and frequency of tests shall be at the Consultant's discretion based on field conditions encountered. Compaction test locations will not necessarily be selected on a random basis. Test locations shall be selected to verify adequacy of compaction levels in areas that are judged to be prone to inadequate compaction (such as close to slope faces and at the fill/bedrock benches). 4.6 Frequency of Compaction Testing: Tests shall be taken at intervals not exceeding 2 feet in vertical rise and/or 1,000 cubic yards of compacted fill soils embankment. In addition, as a guideline, at least one test shall be taken on slope faces for each 5,000 square feet of slope face and/or each 10 feet of vertical height of slope. The Contractor shall assure that fill construction is such that the testing schedule can be accomplished by the Geotechnical Consultant. The Contractor shall stop or slow down the earthwork construction if these minimum standards are not met. 4.7 Compaction Test Locations: The Geotechnical Consultant shall document the approximate elevation and horizontal coordinates of each test location. The Contractor shall coordinate with the project surveyor to assure that sufficient grade stakes are established so that the Geotechnical Consultant can determine the test locations with sufficient accuracy. At a minimum, two grade stakes within a horizontal distance of 100 feet and vertically less than 5 feet apart from potential test locations shall be provided. 6 3030.495 LEIGHTON AND ASSOCIATES, INC. General Earthwork and Grading Specifications 5.0 Subdrain Installation Subdrain systems shall be installed in accordance with the approved geotechnical report(s), the grading plan, and the Standard Details. The Geotechnical Consultant may recommend additional subdrains and/or changes in subdrain extent, location, grade, or material depending on conditions encountered during grading. All subdrains shall be surveyed by a land surveyor/civil engineer for line and grade after installation and prior to burial. Sufficient time should be allowed by the Contractor for these surveys. 6.0 Excavation Excavations, as well as over-excavation for remedial purposes, shall be evaluated by the Geotechnical Consultant during grading. Remedial removal depths shown on geotechnical plans are estimates only. The actual extent of removal shall be determined by the Geotechnical Consultant based on the field evaluation of exposed conditions during grading. Where fill-over-cut slopes are to be graded, the cut portion of the slope shall be made, evaluated, and accepted by the Geotechnical Consultant prior to placement of materials for construction of the fill portion of the slope, unless otherwise recommended by the Geotechnical Consultant. 7.0 Trench Backfills 7.1 Safety: The Contractor shall follow all OHSA and Cal/OSHA requirements for safety of trench excavations. 7.2 Bedding and Backfill: All bedding and backfill of utility trenches shall be done in accordance with the applicable provisions of Standard Specifications of Public Works Construction. Bedding material shall have a Sand Equivalent greater than 30 (SE>30). The bedding shall be placed to 1 foot over the top of the conduit and densified by jetting. Backfill shall be placed and densified to a minimum of 90 percent of maximum from 1 foot above the top of the conduit to the surface. The Geotechnical Consultant shall test the trench backfill for relative compaction. At least one test should be made for every 300 feet of trench and 2 feet of fill. 7.3 Lift Thickness: Lift thickness of trench backfill shall not exceed those allowed in the Standard Specifications of Public Works Construction unless the Contractor can demonstrate to the Geotechnical Consultant that the fill lift can be compacted to the minimum relative compaction by his alternative equipment and method. 7.4 Observation and Testing: The jetting of the bedding around the conduits shall be observed by the Geotechnical Consultant.