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Home My WebLink About34 E Santa Clara ST - 2024 - Geotechnical Investigation GEOTECHNICAL INVESTIGATION ALEXAN ARCADIA PROPOSED MULTI-FAMILY RESIDENTIAL DEVELOPMENT 34 EAST SANTA CLARA STREET ARCADIA, CALIFORNIA PREPARED FOR ARCADIA APARTMENTS, LLC CARLSBAD, CALIFORNIA PROJECT NO. W1304-06-01 SEPTEMBER 19, 2023 03/01/2024 500 N Victory Boulevard ■ Burbank, CA 91502 ■ Telephone 818.841.8388 ■ Fax 818.841.1704 Project No. W1304-06-01 September 19, 2023 Mr. Todd Phillips Trammell Crow Residential 5790 Fleet Street, Suite 140 Carlsbad, California 92008 Subject: GEOTECHNICAL INVESTIGATION ALEXAN ARCADIA PROPOSED MULTI-FAMILY RESIDENTIAL DEVELOPMENT 34 EAST SANTA CLARA STREET, ARCADIA, CALIFORNIA Dear Mr. Phillips: In accordance with your authorization of our proposal dated January 19, 2021, we have performed a geotechnical investigation for the proposed multi-family residential development located at 34 East Santa Clara Street in the City of Arcadia, California. The accompanying report presents the findings of our study, and our conclusions and recommendations pertaining to the geotechnical aspects of proposed design and construction. Based on the results of our investigation, it is our opinion that the site can be developed as proposed, provided the recommendations of this report are followed and implemented during design and construction. If you have any questions regarding this report, or if we may be of further service, please contact the undersigned. Very truly yours, GEOCON WEST, INC. Petrina Zen GE 3217 Jelisa Thomas Adams GE 3092 Susan F. Kirkgard CEG 1754 (Email) Addressee TABLE OF CONTENTS 1. PURPOSE AND SCOPE ................................................................................................................. 1 2. SITE AND PROJECT DESCRIPTION ........................................................................................... 1 3. GEOLOGIC SETTING .................................................................................................................... 2 4. SOIL AND GEOLOGIC CONDITIONS ......................................................................................... 3 4.1 Artificial Fill .......................................................................................................................... 3 4.2 Alluvium ................................................................................................................................ 3 5. GROUNDWATER ........................................................................................................................... 3 6. GEOLOGIC HAZARDS .................................................................................................................. 4 6.1 Surface Fault Rupture ............................................................................................................ 4 6.2 Seismicity ............................................................................................................................... 5 6.3 Seismic Design Criteria ......................................................................................................... 5 6.4 Liquefaction Potential ............................................................................................................ 7 6.5 Slope Stability ........................................................................................................................ 8 6.6 Earthquake-Induced Flooding ................................................................................................ 8 6.7 Tsunamis, Seiches, and Flooding ........................................................................................... 8 6.8 Oil Fields & Methane Potential ............................................................................................. 8 6.9 Subsidence ............................................................................................................................. 9 7. CONCLUSIONS AND RECOMMENDATIONS ......................................................................... 10 7.1 General ................................................................................................................................. 10 7.2 Soil and Excavation Characteristics ..................................................................................... 12 7.3 Minimum Resistivity, pH, and Water-Soluble Sulfate ........................................................ 12 7.4 Grading ................................................................................................................................ 13 7.5 Foundation Design ............................................................................................................... 15 7.6 Foundation Settlement ......................................................................................................... 16 7.7 Miscellaneous Foundations .................................................................................................. 16 7.8 Lateral Design ...................................................................................................................... 17 7.9 Concrete Slabs-on-Grade ..................................................................................................... 17 7.10 Preliminary Pavement Recommendations ........................................................................... 19 7.11 Retaining Wall Design ......................................................................................................... 20 7.12 Dynamic (Seismic) Lateral Forces ....................................................................................... 22 7.13 Retaining Wall Drainage ...................................................................................................... 23 7.14 Elevator Pit Design .............................................................................................................. 24 7.15 Elevator Piston ..................................................................................................................... 24 7.16 Temporary Excavations ....................................................................................................... 25 7.17 Shoring – Soldier Pile Design and Installation .................................................................... 25 7.18 Temporary Tie-Back Anchors ............................................................................................. 31 7.19 Anchor Installation............................................................................................................... 32 7.20 Anchor Testing .................................................................................................................... 32 7.21 Internal Bracing ................................................................................................................... 33 7.22 Stormwater Infiltration ........................................................................................................ 34 7.23 Surface Drainage .................................................................................................................. 35 7.24 Plan Review ......................................................................................................................... 36 LIMITATIONS AND UNIFORMITY OF CONDITIONS LIST OF REFERENCES TABLE OF CONTENTS (Continued) MAPS, TABLES, AND ILLUSTRATIONS Figure 1, Vicinity Map Figure 2A, Site Plan Figure 2B, Cross Section Figure 3, Regional Fault Map Figure 4, Regional Seismicity Map Figures 5 and 6, Retaining Wall Drain Detail Figure 7, Percolation Test Results APPENDIX A FIELD INVESTIGATION Figures A1 through A4, Boring Logs APPENDIX B LABORATORY TESTING Figures B1 through B7, Direct Shear Test Results Figures B8 through B19, Consolidation Test Results Figure B20, Corrosivity Test Results Geocon Project No. W1304-06-01 - 1 - September 19, 2023 GEOTECHNICAL INVESTIGATION 1. PURPOSE AND SCOPE This report presents the results of a geotechnical investigation for the proposed multi-family residential development located at 34 East Santa Clara Street in the City of Arcadia, California (see Vicinity Map, Figure 1). The purpose of the investigation was to evaluate subsurface soil and geologic conditions underlying the site and, based on conditions encountered, to provide conclusions and recommendations pertaining to the geotechnical aspects of design and construction. The scope of this investigation included a site reconnaissance, field exploration, laboratory testing, engineering analysis, and the preparation of this report. The site was explored on February 8, 2021 by excavating four 8-inch diameter borings to depths ranging from approximately 30½ to 40½ feet below the existing ground surface using a truck-mounted, hollow-stem auger drilling machine. The approximate locations of the exploratory borings are depicted on the Site Plan (see Figure 2A). A detailed discussion of the field investigation, including boring logs, is presented in Appendix A. Laboratory tests were performed on selected soil samples obtained during the investigation to determine pertinent physical and chemical soil properties. Appendix B presents a summary of the laboratory test results. The recommendations presented herein are based on analysis of the data obtained during the investigation and our experience with similar soil and geologic conditions. References reviewed to prepare this report are provided in the List of References section. If project details vary significantly from those described herein, Geocon should be contacted to determine the necessity for review and possible revision of this report. 2. SITE AND PROJECT DESCRIPTION The subject site is located at 34 East Santa Clara Street in the City of Arcadia, California. The site is currently occupied by a multi-story office tower, several single-story structures, a two-story office building and associated asphalt paved parking lots. The site is bounded by East Santa Clara Street to the north, by Wheeler Avenue to the south, by commercial structures and asphalt paved parking to the east, and by North Santa Anita Avenue to the west. The topography at the site and in the general site vicinity slopes gently downward towards the south. Surface water drainage at the site appears to be by sheet flow along the existing ground contours to the city streets. Vegetation consists of some isolated trees and shrubs in isolated planter areas. Geocon Project No. W1304-06-01 - 2 - September 19, 2023 Based on the information provided by the Client, it is our understanding that the office tower and the single-story commercial structure located on the west side of the property will remain in place; the existing improvements on the east side of the property will be demolished. The new construction will consist of a seven-story multi-family residential structure to be constructed over up to two levels of subterranean parking (see Figures 2A and 2B). Based on the plans provided to us and due to the sloping nature of the site, the structure will be underlain by one subterranean level on the south side and by two subterranean levels on the north side extending to depths of approximately 15 and 26 feet, respectively, including foundation depths. Due to preliminary nature of the design at this time, wall and column loads were not available. It is anticipated that column loads for the proposed structure will be up to 900 kips, and wall loads will be up to 10 kips per linear foot. Once the design phase and foundation loading configuration proceeds to a more finalized plan, the recommendations within this report should be reviewed and revised, if necessary. Any changes in the design, location or elevation of any structure, as outlined in this report, should be reviewed by this office. Geocon should be contacted to determine the necessity for review and possible revision of this report. 3. GEOLOGIC SETTING The site is located in the north-central San Gabriel Valley, approximately 1.0 mile south of the southern flank of the San Gabriel Mountains. The San Gabriel Valley is an alluvium-filled valley bounded by the Sierra Madre Fault Zone and San Gabriel Mountains on the north, by the Puente Hills on the south, by the Covina and Indian Hills on the east, and by the Raymond Basin on the west. The alluvial deposits are derived from erosion of the San Gabriel Mountains to the north and subsequent deposition by the San Gabriel River, Santa Anita Wash, and other local drainages. The alluvium is estimated to be approximately 200 feet thick at the base of the mountains, extending to hundreds of feet thick in the central portion of the valley. Regionally, the site is located within the northern portion of the Peninsular Ranges geomorphic province. This geomorphic province is characterized by northwest-trending physiographic and geologic features such as the active Whittier Fault located approximately 9.4 miles to the south. The active Raymond Fault, located approximately 0.6 mile to the northwest of the site, forms the local boundary between the Peninsular Ranges geomorphic province and the Transverse Ranges geomorphic province to the north. Geocon Project No. W1304-06-01 - 3 - September 19, 2023 4. SOIL AND GEOLOGIC CONDITIONS Based on our field investigation and published geologic maps of the area, the site is underlain by artificial fill and Holocene age alluvium comprised of alluvial channel and outwash deposits consisting of varying amounts of silt, sand, and gravel (California Geological Survey [CGS], 2010). Detailed stratigraphic profiles are provided on the boring logs in Appendix A. 4.1 Artificial Fill Artificial fill was encountered in the exploratory borings to a maximum depth of 4 feet below existing ground surface. The artificial fill generally consists of dark brown silty sand. The fill is characterized as slightly moist to moist and medium dense. The fill is likely the result of past grading or construction activities at the site. Deeper fill may exist between excavations and in other portions of the site that were not directly explored. 4.2 Alluvium Holocene age alluvium was encountered beneath the artificial fill and consists primarily of light brown to brown and reddish brown interbedded silty sand, poorly graded sand, and well-graded sand with varying amounts of fine to coarse gravel. The alluvium is characterized as dry to moist and medium dense to very dense. 5. GROUNDWATER Review of the Seismic Hazard Evaluation of the Mount Wilson 7.5-minute Quadrangle (California Division of Mines and Geology [CDMG], 1998) indicates that the historically highest groundwater level in the immediate area is approximately 100 to 150 feet beneath the ground surface. Groundwater information presented in this document is generated from data collected in the early 1900’s to the late 1990s. Based on current groundwater basin management practices, it is unlikely that groundwater levels will ever exceed the historic high levels. Groundwater was not encountered in our borings drilled to a maximum depth of 40½ feet beneath the existing ground surface. Considering the reported historic high groundwater level (CDMG, 1998), the lack of groundwater encountered in our borings, and the depth of the proposed construction, it is unlikely that static groundwater will be encountered during construction or adversely impact the proposed development. However, it is not uncommon for groundwater levels to vary seasonally or for groundwater seepage conditions to develop where none previously existed, especially in impermeable fine-grained soils which are heavily irrigated or after seasonal rainfall. In addition, recent requirements for stormwater infiltration could result in shallower seepage conditions in the immediate site vicinity. Proper surface drainage of irrigation and precipitation will be critical for future performance of the project. Recommendations for drainage are provided in the Surface Drainage section of this report (see Section 7.23). Geocon Project No. W1304-06-01 - 4 - September 19, 2023 6. GEOLOGIC HAZARDS 6.1 Surface Fault Rupture The numerous faults in Southern California include Holocene-active, pre-Holocene, and inactive faults. The criteria for these major groups are based on criteria developed by the California Geological Survey (CGS, formerly known as CDMG) for the Alquist-Priolo Earthquake Fault Zone Program (CGS, 2018). By definition, a Holocene-active fault is one that has had surface displacement within Holocene time (about the last 11,700 years). A pre-Holocene fault has demonstrated surface displacement during Quaternary time (approximately the last 1.6 million years) but has had no known Holocene movement. Faults that have not moved in the last 1.6 million years are considered inactive. The site is not within a state-designated Alquist-Priolo Earthquake Fault Zone (CGS, 2021b; CGS, 2017) or a city-designated Fault Hazard Management Zone (City of Arcadia, 2010) for surface fault rupture hazards. No Holocene-active or pre-Holocene faults with the potential for surface fault rupture are known to pass directly beneath the site. Therefore, the potential for surface rupture due to faulting occurring beneath the site during the design life of the proposed development is considered low. However, the site is located in the seismically active Southern California region, and could be subjected to moderate to strong ground shaking in the event of an earthquake on one of the many active Southern California faults. The faults in the vicinity of the site are shown in Figure 3, Regional Fault Map. The closest Holocene-active fault to the site is the Raymond Fault located approximately 0.6 mile to the northwest (CGS, 2017). Other nearby Holocene-active faults are the Sierra Madre Fault Zone, the Duarte Fault, the East Montebello Fault, and the Whittier Fault located approximately 1.8 miles north, 2.2 miles northeast, 6.3 miles southwest, and 9.4 miles south of the site, respectively. (USGS, 2006; Ziony and Jones, 1989). The active San Andreas Fault Zone is located approximately 23 miles northeast of the site (Ziony and Jones, 1989). Several buried thrust faults, commonly referred to as blind thrusts, underlie the Los Angeles Basin and the San Gabriel Valley at depth. These faults are not exposed at the ground surface and are typically identified at depths greater than 3.0 kilometers. The October 1, 1987 Mw 5.9 Whittier Narrows earthquake and the January 17, 1994 Mw 6.7 Northridge earthquake were a result of movement on the Puente Hills Blind Thrust and the Northridge Thrust, respectively. These thrust faults and others in the greater Los Angeles area are not exposed at the surface and do not present a potential surface fault rupture hazard at the site; however, these deep thrust faults are considered active features capable of generating future earthquakes that could result in moderate to significant ground shaking at the site. Geocon Project No. W1304-06-01 - 5 - September 19, 2023 6.2 Seismicity As with all of Southern California, the site has experienced historic earthquakes from various regional faults. The seismicity of the region surrounding the site was formulated based on research of an electronic database of earthquake data. The epicenters of recorded earthquakes with magnitudes equal to or greater than 5.0 in the site vicinity are depicted on Figure 4, Regional Seismicity Map. A partial list of moderate to major magnitude earthquakes that have occurred in the Southern California area within the last 100 years is included in the following table. LIST OF HISTORIC EARTHQUAKES Earthquake (Oldest to Youngest) Date of Earthquake Magnitude Distance to Epicenter (Miles) Direction to Epicenter Near Redlands July 23, 1923 6.3 46 ESE Long Beach March 10, 1933 6.4 36 S Tehachapi July 21, 1952 7.5 81 NW San Fernando February 9, 1971 6.6 28 NW Whittier Narrows October 1, 1987 5.9 6 SW Sierra Madre June 28, 1991 5.8 8 NNE Landers June 28, 1992 7.3 91 E Big Bear June 28, 1992 6.4 69 E Northridge January 17, 1994 6.7 29 W Hector Mine October 16, 1999 7.1 105 ENE Ridgecrest July 5, 2019 7.1 115 NNE The site could be subjected to strong ground shaking in the event of an earthquake. However, this hazard is common in Southern California and the effects of ground shaking can be mitigated if the proposed structures are designed and constructed in conformance with current building codes and engineering practices. 6.3 Seismic Design Criteria The following table summarizes the site-specific design criteria obtained from the 2022 California Building Code (CBC; Based on the 2021 International Building Code [IBC] and ASCE 7-16), Chapter 16 Structural Design, Section 1613 Earthquake Loads. The data was calculated using the online application U.S. Seismic Design Maps, provided by the Structural Engineers Association of California (SEAOC). The short spectral response uses a period of 0.2 second. We evaluated the Site Class based on the discussion in Section 1613.2.2 of the 2022 CBC and Table 20.3-1 of ASCE 7-16. The values presented below are for the risk-targeted maximum considered earthquake (MCER). Geocon Project No. W1304-06-01 - 6 - September 19, 2023 2022 CBC SEISMIC DESIGN PARAMETERS Parameter Value 2022 CBC Reference Site Class D Section 1613.2.2 MCER Ground Motion Spectral Response Acceleration – Class B (short), SS 1.963g Figure 1613.2.1(1) MCER Ground Motion Spectral Response Acceleration – Class B (1 sec), S1 0.719g Figure 1613.2.1(3) Site Coefficient, FA 1 Table 1613.2.3(1) Site Coefficient, FV 1.7* Table 1613.2.3(2) Site Class Modified MCER Spectral Response Acceleration (short), SMS 1.963g Section 1613.2.3 (Eqn 16-20) Site Class Modified MCER Spectral Response Acceleration – (1 sec), SM1 1.222g* Section 1613.2.3 (Eqn 16-21) 5% Damped Design Spectral Response Acceleration (short), SDS 1.309g Section 1613.2.4 (Eqn 16-22) 5% Damped Design Spectral Response Acceleration (1 sec), SD1 0.815g* Section 1613.2.4 (Eqn 16-23) *Per Supplement 3 of ASCE 7-16, a ground motion hazard analysis (GMHA) shall be performed for projects on Site Class “D” sites with 1-second spectral acceleration (S1) greater than or equal to 0.2g, which is true for this site. However, Supplement 3 of ASCE 7-16 provides an exception stating that that the GMHA may be waived provided that the parameter SM1 is increased by 50% for all applications of SM1. The values for parameters SM1 and SD1 presented above have not been increased in accordance with Supplement 3 of ASCE 7-16. The table below presents the mapped maximum considered geometric mean (MCEG) seismic design parameters for projects located in Seismic Design Categories of D through F in accordance with ASCE 7-16. ASCE 7-16 PEAK GROUND ACCELERATION Parameter Value ASCE 7-16 Reference Mapped MCEG Peak Ground Acceleration, PGA 0.854g Figure 22-9 Site Coefficient, FPGA 1.1 Table 11.8-1 Site Class Modified MCEG Peak Ground Acceleration, PGAM 0.939g Section 11.8.3 (Eqn 11.8-1) Deaggregation of the MCE peak ground acceleration was performed using the USGS online Unified Hazard Tool, 2014 Conterminous U.S. Dynamic edition (v4.2.0). The result of the deaggregation analysis indicates that the predominant earthquake contributing to the MCE peak ground acceleration is characterized as a 7.05 magnitude event occurring at a hypocentral distance of 9.09 kilometers from the site. Geocon Project No. W1304-06-01 - 7 - September 19, 2023 Deaggregation was also performed for the Design Earthquake (DE) peak ground acceleration, and the result of the analysis indicates that the predominant earthquake contributing to the DE peak ground acceleration is characterized as a 6.96 magnitude occurring at a hypocentral distance of 14.07 kilometers from the site. Conformance to the criteria in the above tables for seismic design does not constitute any kind of guarantee or assurance that significant structural damage or ground failure will not occur if a large earthquake occurs. The primary goal of seismic design is to protect life, not to avoid all damage, since such design may be economically prohibitive. 6.4 Liquefaction Potential Liquefaction is a phenomenon in which loose, saturated, relatively cohesionless soil deposits lose shear strength during strong ground motions. Primary factors controlling liquefaction include intensity and duration of ground motion, gradation characteristics of the subsurface soils, in-situ stress conditions, and the depth to groundwater. Liquefaction is typified by a loss of shear strength in the liquefied layers due to rapid increases in pore water pressure generated by earthquake accelerations. The current standard of practice, as outlined in the “Recommended Procedures for Implementation of DMG Special Publication 117, Guidelines for Analyzing and Mitigating Liquefaction in California” and “Special Publication 117A, Guidelines for Evaluating and Mitigating Seismic Hazards in California” requires liquefaction analysis to a depth of 50 feet below the lowest portion of the proposed structure. Liquefaction typically occurs in areas where the soils below the water table are composed of poorly consolidated, fine to medium-grained, primarily sandy soil. In addition to the requisite soil conditions, the ground acceleration and duration of the earthquake must also be of a sufficient level to induce liquefaction. The Seismic Hazards Zone Map for the Mount Wilson Quadrangle (CDMG, 1999; CGS, 2017) indicates that the site is not located within a zone of required investigation for liquefaction. In addition, the City of Arcadia General Plan (2010) and the County of Los Angeles Safety Element (Leighton, 1990), indicate that the site is not located within an area designated as having a potential for liquefaction. Groundwater was not encountered in our borings drilled to a maximum depth of 40½ feet beneath the existing ground surface and the historic high groundwater level in the area is reported to be approximately 100 to 150 feet beneath the existing ground surface (CDMG, 1998). Based on these considerations, it is our opinion that the potential for liquefaction and associated ground deformations beneath the site is very low. Geocon Project No. W1304-06-01 - 8 - September 19, 2023 6.5 Slope Stability The site is relatively level and the topography in the site vicinity slopes downward toward the south. The City of Arcadia General Plan (2010) and County of Los Angeles Safety Element (Leighton, 1990), indicate that the site is not located in a “hillside area” or an area identified as having a potential for slope stability hazards. Also, the State of California (CDMG, 1999; CGS, 2017) and the City of Arcadia (2010) indicate that the site is not located within a zone of required investigation for earthquake-induced landslides. There are no known landslides near the site, nor is the site in the path of any known or potential landslides. Therefore, the potential for slope stability hazards to adversely impact the site is considered low. 6.6 Earthquake-Induced Flooding Earthquake-induced flooding is inundation caused by failure of dams or other water-retaining structures due to earthquakes. The City of Arcadia (2010) indicates that the site is located within the potential inundation area for Santa Anita Dam. However, this reservoir, as well as others in California, are continually monitored by various governmental agencies (such as the State of California Division of Safety of Dams and the U.S. Army Corps of Engineers) to guard against the threat of dam failure. Current design, construction practices, and ongoing programs of review, modification, or total reconstruction of existing dams are intended to ensure that all dams are capable of withstanding the maximum considered earthquake (MCE) for the site. Therefore, the potential for inundation at the site as a result of an earthquake-induced dam failure is considered low. 6.7 Tsunamis, Seiches, and Flooding The site is not located within a coastal area. Therefore, tsunamis are not considered a significant hazard at the site. Seiches are large waves generated in enclosed bodies of water in response to ground shaking. No major water-retaining structures are located immediately up gradient from the project site. Therefore, flooding from a seismically induced seiche is considered unlikely. The site is within a Zone X as defined by the Federal Emergency Management Agency (FEMA, 2021; LACDPW, 2021b). Sites within a Zone X have a minimal potential for flooding (FEMA, 2021). 6.8 Oil Fields & Methane Potential Review of the California Geologic Energy Management Division (CalGEM) Well Finder Website indicates that the site is not located within the limits of an oilfield and oil or gas wells are not located within ½-mile of the site. However, due to the voluntary nature of record reporting by the oil well drilling companies, wells may be improperly located or not shown on the location map. Undocumented wells could be encountered during construction. Any wells encountered will need to be properly abandoned in accordance with the current requirements of the CalGEM Geocon Project No. W1304-06-01 - 9 - September 19, 2023 As previously indicated, the site is not located within an oilfield. Therefore, the potential for methane or other volatile gases to occur at the site is considered very low. However, should it be determined that a methane study is required for the proposed development it is recommended that a qualified methane consultant be retained to perform the study and provide mitigation measures as necessary. 6.9 Subsidence Subsidence occurs when a large portion of land is displaced vertically, usually due to the withdrawal of groundwater, oil, or natural gas. Soils that are particularly subject to subsidence include those with high silt or clay content. The site is not located within an area of known ground subsidence. No large-scale extraction of groundwater, gas, oil, or geothermal energy is occurring or planned at the site or in the general site vicinity. There appears to be little or no potential for ground subsidence due to withdrawal of fluids or gases at the site. Geocon Project No. W1304-06-01 - 10 - September 19, 2023 7. CONCLUSIONS AND RECOMMENDATIONS 7.1 General 7.1.1 It is our opinion that neither soil nor geologic conditions were encountered during the investigation that would preclude the construction of the proposed development provided the recommendations presented herein are followed and implemented during design and construction. 7.1.2 Up to 4 feet of existing artificial fill was encountered during the site investigation. The existing fill encountered is believed to be the result of past grading and construction activities at the site. Deeper fill may exist in other areas of the site that were not directly explored. Future demolition of the existing structures which occupy the site will likely disturb the upper few feet of soil. It is our opinion that the existing fill, in its present condition, is not suitable for direct support of proposed foundations or slabs. The existing fill and site soils are suitable for re-use as engineered fill provided the recommendations in the Grading section of this report are followed (see Section 7.4). Excavation for the subterranean levels are anticipated to penetrate through the existing artificial fill and expose undisturbed alluvial soils throughout the excavation bottom. 7.1.3 Groundwater was not encountered during site exploration and the current groundwater table is sufficiently deep that it not expected to be encountered during construction. However, local seepage could be encountered during excavation of the subterranean level, especially if conducted during the rainy season. 7.1.4 Based on these considerations, the proposed structure may be supported on conventional foundation system deriving support in the competent alluvium found at and below a depth of 12 feet. Foundations should be deepened as necessary to penetrate through soft or unsuitable alluvium at the direction of the Geotechnical Engineer. All foundation excavations must be observed and approved by the Geotechnical Engineer (a representative of Geocon), prior to placing steel or concrete. Recommendations for the design of a conventional foundation system are provided in Section 7.5. 7.1.5 Excavations up to 26 feet in vertical height are anticipated for construction of the subterranean levels, including foundation depths. Due to the depth of the excavation and the proximity to the property lines, city streets and adjacent offsite structures, excavation of the proposed subterranean level will likely require sloping and shoring measures in order to provide a stable excavation. Where shoring is required it is recommended that a soldier pile shoring system be utilized. In addition, where the proposed excavation will be deeper than and adjacent to an offsite structure, the proposed shoring should be designed to resist the surcharge imposed by the adjacent offsite structure. Recommendations for shoring are provided in Section 7.17 of this report. Geocon Project No. W1304-06-01 - 11 - September 19, 2023 7.1.6 Due to the granular nature of the soils, moderate to excessive caving is anticipated during excavation activities. The contractor should be aware that casing may be required during shoring pile installation and formwork may be required to prevent caving of shallow spread foundation excavations. 7.1.7 Due to the nature of the proposed design and intent for a subterranean level, waterproofing of subterranean walls and slabs is suggested. Particular care should be taken in the design and installation of waterproofing to avoid moisture problems, or actual water seepage into the structure through any normal shrinkage cracks which may develop in the concrete walls, floor slab, foundations and/or construction joints. The design and inspection of the waterproofing is not the responsibility of the geotechnical engineer. A waterproofing consultant should be retained in order to recommend a product or method which would provide protection to subterranean walls, floor slabs and foundations. 7.1.8 Foundations for small outlying structures, such as block walls up to 6 feet in height, planter walls or trash enclosures, which will not be tied to the proposed structure, may be supported on conventional foundations deriving support on a minimum of 12 inches of newly placed engineered fill, which extends laterally at least 12 inches beyond the foundation area. Where excavation and compaction cannot be performed, foundations may derive support directly in the competent undisturbed alluvial soils found at or below a depth of 24 inches, and should be deepened as necessary to maintain a minimum 12 inch embedment into the recommended bearing materials. If the soils exposed in the excavation bottom are soft or loose, compaction of the soils will be required prior to placing steel or concrete. Compaction of the foundation excavation bottom is typically accomplished with a compaction wheel or mechanical whacker and must be observed and approved by a Geocon representative. 7.1.9 Where new paving is to be placed, it is recommended that all existing fill and soft alluvial soils be excavated and properly compacted for paving support. The client should be aware that excavation and compaction of all existing fill and soft alluvial soils in the area of new paving is not required; however, paving constructed over existing uncertified fill or unsuitable alluvial soil may experience increased settlement and/or cracking, and may therefore have a shorter design life and increased maintenance costs. As a minimum, the upper 12 inches of subgrade soil should be scarified and properly compacted for paving support. Paving recommendations are provided in Preliminary Pavement Recommendations section of this report (see Section 7.10). 7.1.10 Based on the results of percolation testing performed at the site, a stormwater infiltration system is considered feasible for this project. Results of percolation testing are provided in the Stormwater Infiltration section of this report (see Section 7.22). Geocon Project No. W1304-06-01 - 12 - September 19, 2023 7.1.11 Once the design and foundation loading configuration for the proposed structure proceeds to a more finalized plan, the recommendations within this report should be reviewed and revised, if necessary. Based on the final foundation loading configurations, the potential for settlement should be re-evaluated by this office. 7.1.12 Any changes in the design, location or elevation, as outlined in this report, should be reviewed by this office. Geocon should be contacted to determine the necessity for review and possible revision of this report. 7.2 Soil and Excavation Characteristics 7.2.1 The in-situ soils can be excavated with moderate effort using conventional excavation equipment. Due to the granular nature of the soils, moderate to excessive caving should be anticipated in vertical excavations. The contractor should be aware that casing may be required during shoring pile installation and formwork may be required to prevent caving of shallow spread foundation excavations. 7.2.2 It is the responsibility of the contractor to ensure that all excavations and trenches are properly shored and maintained in accordance with applicable OSHA rules and regulations to maintain safety and maintain the stability of existing adjacent improvements. 7.2.3 All onsite excavations must be conducted in such a manner that potential surcharges from existing structures, construction equipment, and vehicle loads are resisted. The surcharge area may be defined by a 1:1 projection down and away from the bottom of an existing foundation or vehicle load. Penetrations below this 1:1 projection will require special excavation measures such as sloping or shoring. Excavation recommendations are provided in the Temporary Excavations section of this report (see Section 7.16). 7.2.4 Based on depth of the proposed subterranean levels, the proposed structure would not be prone to the effects of expansive soils. The soils encountered at the site are primarily granular in nature and are considered to be “non-expansive”. The recommendations presented in this report assume that near surface foundations and slabs will derive support in these materials with a “low” expansion potential (EI <= 50). 7.3 Minimum Resistivity, pH, and Water-Soluble Sulfate 7.3.1 Potential of Hydrogen (pH) and resistivity testing as well as chloride content testing were performed on representative samples of soil to generally evaluate the corrosion potential to surface utilities. The tests were performed in accordance with California Test Method Nos. 643 and 422 and indicate that the soils are considered “mildly corrosive” with respect to corrosion of buried ferrous metals on site. The results are presented in Appendix B (Figure B20) and should be considered for design of underground structures. Geocon Project No. W1304-06-01 - 13 - September 19, 2023 7.3.2 Laboratory tests were performed on representative samples of the site materials to measure the percentage of water-soluble sulfate content. Results from the laboratory water-soluble sulfate tests are presented in Appendix B (Figure B20) and indicate that the on-site materials possess a sulfate exposure class of “S0” to concrete structures as defined by 2019 CBC Section 1904 and ACI 318-14 Table 19.3.1.1. 7.3.3 Geocon West, Inc. does not practice in the field of corrosion engineering and mitigation. If corrosion sensitive improvements are planned, it is recommended that a corrosion engineer be retained to evaluate corrosion test results and incorporate the necessary precautions to avoid premature corrosion of buried metal pipes and concrete structures in direct contact with the soils. 7.4 Grading 7.4.1 Grading is anticipated to include excavation of site soils for the subterranean level, foundations, and utility trenches, as well as placement of backfill for walls, ramps, and trenches. 7.4.2 Earthwork should be observed, and compacted fill tested by representatives of Geocon West, Inc. The existing fill and alluvial soil encountered during exploration is suitable for re-use as engineered fill, provided any encountered oversize material (greater than 6 inches) and any encountered deleterious debris are removed. 7.4.3 A preconstruction conference should be held at the site prior to the beginning of grading operations with the owner, contractor, civil engineer, geotechnical engineer, and building official in attendance. Special soil handling requirements can be discussed at that time. 7.4.4 Grading should commence with the removal of all existing vegetation and existing improvements from the area to be graded. Deleterious debris such as wood and root structures should be exported from the site and should not be mixed with the fill soils. Asphalt and concrete should not be mixed with the fill soils unless approved by the Geotechnical Engineer. All existing underground improvements planned for removal should be completely excavated and the resulting depressions properly backfilled in accordance with the procedures described herein. Once a clean excavation bottom has been established it must be observed and approved in writing by the Geotechnical Engineer (a representative of Geocon West, Inc.). 7.4.5 The foundation system for the proposed structure may derive support in the competent undisturbed alluvial soils found at and below a depth of 12 feet. 7.4.6 All excavations must be observed and approved in writing by the Geotechnical Engineer (a representative of Geocon) prior to placing any fill or foundation construction. Geocon Project No. W1304-06-01 - 14 - September 19, 2023 7.4.7 All fill and backfill soils should be placed in horizontal loose layers approximately 6 to 8 inches thick, moisture conditioned to optimum moisture content, and properly compacted to a minimum of 90 percent of the maximum dry density in accordance with ASTM D 1557 (latest edition). 7.4.8. Where new paving is to be placed, it is recommended that all existing fill and soft alluvium be excavated and properly compacted for paving support. As a minimum, the upper 12 inches of soil should be scarified, moisture conditioned to optimum moisture content, and compacted to at least 95 percent relative compaction, as determined by ASTM D 1557 (latest edition). Paving recommendations are provided in Preliminary Pavement Recommendations section of this report (see Section 7.10). 7.4.9 Foundations for small outlying structures, such as block walls less than 6 feet high, planter walls or trash enclosures, which will not be tied to the proposed building, may be supported on conventional foundations deriving support on a minimum of 12 inches of newly placed engineered fill which extends laterally at least 12 inches beyond the foundation area. Where excavation and proper compaction cannot be performed, foundations may derive support directly in the undisturbed alluvial soils found at or below a depth of 24 inches, and should be deepened as necessary to maintain a minimum 12 inch embedment into the recommended bearing materials. If the soils exposed in the excavation bottom are soft or loose, compaction of the soils will be required prior to placing steel or concrete. Compaction of the foundation excavation bottom is typically accomplished with a compaction wheel or mechanical whacker and must be observed and approved by a Geocon representative. 7.4.10 Although not anticipated for this project, all imported fill shall be observed, tested, and approved by Geocon West, Inc. prior to bringing soil to the site. Rocks larger than 6 inches in diameter shall not be used in the fill. If necessary, import soils used as structural fill should have an expansion index less than 20 and corrosivity properties that are equally or less detrimental to that of the existing onsite soils (see Figure B20). 7.4.11 Utility trenches should be properly backfilled in accordance with the following recommendations. The pipe should be bedded with clean sands (Sand Equivalent greater than 30) to a depth of at least 1 foot over the pipe, and the bedding material must be inspected and approved in writing by the Geotechnical Engineer (a representative of Geocon). The use of gravel is not acceptable unless used in conjunction with filter fabric to prevent the gravel from having direct contact with soil. The remainder of the trench backfill may be derived from onsite soil or approved import soil, compacted as necessary, until the required compaction is obtained. The use of minimum 2-sack slurry as backfill is also acceptable. Prior to placing any bedding materials or pipes, the excavation bottom must be observed and approved in writing by the Geotechnical Engineer (a representative of Geocon). Geocon Project No. W1304-06-01 - 15 - September 19, 2023 7.4.12 All trench and foundation excavation bottoms must be observed and approved in writing by the Geotechnical Engineer (a representative of Geocon), prior to placing bedding materials, fill, steel, gravel, or concrete. 7.5 Foundation Design 7.5.1 The proposed structure may be supported on a conventional foundation system deriving support in the competent alluvium found at and below a depth of 12 feet. Foundations should be deepened as necessary to penetrate through soft or unsuitable alluvium at the direction of the Geotechnical Engineer. All foundation excavations must be observed and approved by the Geotechnical Engineer (a representative of Geocon), prior to placing steel or concrete. 7.5.2 Continuous footings may be designed for an allowable bearing capacity of 2,500 pounds per square foot (psf), and should be a minimum of 12 inches in width, 18 inches in depth below the lowest adjacent grade, and 12 inches into the recommended bearing material. 7.5.3 Isolated spread foundations may be designed for an allowable bearing capacity of 3,000 psf, and should be a minimum of 24 inches in width, 18 inches in depth below the lowest adjacent grade, and 12 inches into the recommended bearing material. 7.5.4 The allowable soil bearing pressure above may be increased by 250 psf and 500 psf for each additional foot of foundation width and depth, respectively, up to a maximum allowable soil bearing pressure of 4,000 psf. 7.5.5 The allowable bearing pressures may be increased by one-third for transient loads due to wind or seismic forces. 7.5.6 If depth increases are utilized for the perimeter foundations, this office should be provided a copy of the final construction plans so that the excavation recommendations presented herein could be properly reviewed and revised if necessary. 7.5.7 Continuous footings should be reinforced with four No. 4 steel reinforcing bars, two placed near the top of the footing and two near the bottom. Reinforcement for spread footings should be designed by the project structural engineer. 7.5.8 The above foundation dimensions and minimum reinforcement recommendations are based on soil conditions and building code requirements only, and are not intended to be used in lieu of those required for structural purposes. 7.5.9 No special subgrade presaturation is required prior to placement of concrete. However, the slab and foundation subgrade should be sprinkled as necessary; to maintain a moist condition as would be expected in any concrete placement. Geocon Project No. W1304-06-01 - 16 - September 19, 2023 7.5.10 Foundation excavations should be observed and approved in writing by the Geotechnical Engineer (a representative of Geocon West, Inc.), prior to the placement of reinforcing steel and concrete to verify that the excavations and exposed soil conditions are consistent with those anticipated. If unanticipated soil conditions are encountered, foundation modifications may be required. 7.5.11 This office should be provided a copy of the final construction plans so that the excavation recommendations presented herein could be properly reviewed and revised if necessary. 7.6 Foundation Settlement 7.6.1 The maximum expected static settlement for a structure supported on a conventional foundation system deriving support in the recommended bearing materials and designed with a maximum bearing pressure of 4,000 psf is estimated to be less than 1¼ inches and occur below the heaviest loaded structural element. Settlement of the foundation system is expected to occur on initial application of loading. Differential settlement is not expected to exceed ¾ inch over a distance of 20 feet. 7.6.2 Once the design and foundation loading configuration for the proposed structure proceeds to a more finalized plan, the estimated settlements presented in this report should be reviewed and revised, if necessary. If the final foundation loading configurations are greater than the assumed loading conditions, the potential for settlement should be reevaluated by this office. 7.7 Miscellaneous Foundations 7.7.1 Foundations for small outlying structures, such as block walls up to 6 feet in height, planter walls or trash enclosures which will not be tied to the proposed structure may be supported on conventional foundations bearing on a minimum of 12 inches of newly placed engineered fill which extends laterally at least 12 inches beyond the foundation area. Where excavation and compaction cannot be performed, such as adjacent to property lines, foundations may derive support in the undisturbed alluvial soils found at or below a depth of 24 inches, and should be deepened as necessary to maintain a minimum 12 inch embedment into the recommended bearing materials. 7.7.2 If the soils exposed in the excavation bottom are soft, compaction of the soft soils will be required prior to placing steel or concrete. Compaction of the foundation excavation bottom is typically accomplished with a compaction wheel or mechanical whacker and must be observed and approved by a Geocon representative. Miscellaneous foundations may be designed for a bearing value of 1,500 psf, and should be a minimum of 12 inches in width, 18 inches in depth below the lowest adjacent grade and 12 inches into the recommended bearing material. The allowable bearing pressure may be increased by up to one-third for transient loads due to wind or seismic forces. Geocon Project No. W1304-06-01 - 17 - September 19, 2023 7.7.3 Foundation excavations should be observed and approved in writing by the Geotechnical Engineer (a representative of Geocon West, Inc.), prior to the placement of reinforcing steel and concrete to verify that the excavations and exposed soil conditions are consistent with those anticipated. 7.8 Lateral Design 7.8.1 Resistance to lateral loading may be provided by friction acting at the base of foundations, slabs and by passive earth pressure. An allowable coefficient of friction of 0.4 may be used with the dead load forces in the competent alluvial soils and properly compacted engineered fill. 7.8.2 Passive earth pressure for the sides of foundations and slabs poured against properly compacted engineered fill or competent alluvial soils may be computed as an equivalent fluid having a density of 330 pcf with a maximum earth pressure of 3,300 psf. When combining passive and friction for lateral resistance, the passive component should be reduced by one-third. 7.9 Concrete Slabs-on-Grade 7.9.1 Exterior concrete slabs-on-grade subject to vehicle loading should be designed in accordance with the recommendations in the Preliminary Pavement Recommendations section of this report (Section 7.10). 7.9.2 Unless specifically evaluated and designed by a qualified structural engineer, the slab-on-grade and ramp for the subterranean parking garage slab-on-grade should be a minimum of 5 inches of concrete reinforced with No. 3 steel reinforcing bars placed 18 inches on center in both horizontal directions and positioned vertically near the slab midpoint. The concrete slab-on-grade and ramp may derive support directly on the undisturbed alluvial soils at the excavation bottom as well as compacted soils, if necessary. Any disturbed soils should be properly compacted for slab support. Soil placed and compacted for ramp and slab support should be moisture conditioned to optimum moisture content and properly compacted to at least 95 percent relative compaction, as determined by ASTM Test Method D 1557 (latest edition) for ramp support. 7.9.3 It is our understanding that a project-specific vapor retarder has been designed by a qualified Consultant. The vapor retarder and slab underlayment should follow the recommendations of the project-specific vapor mitigation design. Geocon should be contacted to provide additional recommendations if areas of the project will use slab-on-grade which are not required to follow the project-specific vapor mitigation design. Geocon Project No. W1304-06-01 - 18 - September 19, 2023 7.9.4 Due to the nature of the proposed design and intent for a subterranean level, waterproofing of subterranean walls and slabs is suggested. Particular care should be taken in the design and installation of waterproofing to avoid moisture problems, or actual water seepage into the structure through any normal shrinkage cracks which may develop in the concrete walls, floor slab, foundations and/or construction joints. The design and inspection of the waterproofing is not the responsibility of the geotechnical engineer. A waterproofing consultant should be retained in order to recommend a product or method, which would provide protection to subterranean walls, floor slabs and foundations. 7.9.5 For seismic design purposes, a coefficient of friction of 0.4 may be utilized between concrete slabs and subgrade soils without a moisture barrier, and 0.15 for slabs underlain by a moisture barrier. 7.9.6 Exterior slabs for walkways or flatwork, not subject to traffic loads, should be at least 4 inches thick and reinforced with No. 3 steel reinforcing bars placed 18 inches on center in both horizontal directions, positioned near the slab midpoint. Prior to construction of slabs, the upper 12 inches of subgrade should be moistened to optimum moisture content and properly compacted to at least 95 percent relative compaction, as determined by ASTM Test Method D 1557 (latest edition). Crack control joints should be spaced at intervals not greater than 10 feet and should be constructed using saw-cuts or other methods as soon as practical following concrete placement. Crack control joints should extend a minimum depth of one- fourth the slab thickness. The project structural engineer should design construction joints as necessary. 7.9.7 The recommendations of this report are intended to reduce the potential for cracking of slabs due to settlement. However, even with the incorporation of the recommendations presented herein, foundations, stucco walls, and slabs-on-grade may exhibit some cracking due to minor soil movement and/or concrete shrinkage. The occurrence of concrete shrinkage cracks is independent of the supporting soil characteristics. Their occurrence may be reduced and/or controlled by limiting the slump of the concrete, proper concrete placement and curing, and by the placement of crack control joints at periodic intervals, in particular, where re-entrant slab corners occur. Geocon Project No. W1304-06-01 - 19 - September 19, 2023 7.10 Preliminary Pavement Recommendations 7.10.1 Where new paving is to be placed, it is recommended that all existing fill and soft or unsuitable alluvial materials be excavated and properly recompacted for paving support. The client should be aware that excavation and compaction of all existing artificial fill and soft alluvium in the area of new paving is not required; however, paving constructed over existing unsuitable material may experience increased settlement and/or cracking, and may therefore have a shorter design life and increased maintenance costs. As a minimum, the upper 12 inches of paving subgrade should be scarified, moisture conditioned to optimum moisture content, and properly compacted to at least 95 percent relative compaction, as determined by ASTM Test Method D 1557 (latest edition). 7.10.2 The following pavement sections are based on an assumed R-Value of 35. Once site grading activities are complete an R-Value should be obtained by laboratory testing to confirm the properties of the soils serving as paving subgrade, prior to placing pavement. 7.10.3 The Traffic Indices listed below are estimates. Geocon does not practice in the field of traffic engineering. The actual Traffic Index for each area should be determined by the project civil engineer. If pavement sections for Traffic Indices other than those listed below are required, Geocon should be contacted to provide additional recommendations. Pavement thicknesses were determined following procedures outlined in the California Highway Design Manual (Caltrans). It is anticipated that the majority of traffic will consist of automobile and large truck traffic. PRELIMINARY PAVEMENT DESIGN SECTIONS Location Estimated Traffic Index (TI) Asphalt Concrete (inches) Class 2 Aggregate Base (inches) Automobile Parking And Driveways 4.0 3.0 4.0 Trash Truck & Fire Lanes 7.0 4.0 9.0 7.10.4 Asphalt concrete should conform to Section 203-6 of the “Standard Specifications for Public Works Construction” (Green Book). Class 2 aggregate base materials should conform to Section 26-1.02A of the “Standard Specifications of the State of California, Department of Transportation” (Caltrans). The use of Crushed Miscellaneous Base in lieu of Class 2 aggregate base is acceptable. Crushed Miscellaneous Base should conform to Section 200-2.4 of the “Standard Specifications for Public Works Construction” (Green Book). Geocon Project No. W1304-06-01 - 20 - September 19, 2023 7.10.5 Unless specifically designed and evaluated by the project structural engineer, where exterior concrete paving will be utilized for support of vehicles, it is recommended that the concrete be a minimum of 6 inches thick and reinforced with No. 3 steel reinforcing bars placed 18 inches on center in both horizontal directions. Concrete paving supporting vehicular traffic should be underlain by a minimum of 4 inches of aggregate base and a properly compacted subgrade. The subgrade and base material should be compacted to 95 percent relative compaction as determined by ASTM Test Method D 1557 (latest edition). 7.10.6 The performance of pavements is highly dependent upon providing positive surface drainage away from the edge of pavements. Ponding of water on or adjacent to the pavement will likely result in saturation of the subgrade materials and subsequent cracking, subsidence and pavement distress. If planters are planned adjacent to paving, it is recommended that the perimeter curb be extended at least 12 inches below the bottom of the aggregate base to minimize the introduction of water beneath the paving. 7.11 Retaining Wall Design 7.11.1 The recommendations presented below are generally applicable to the design of rigid concrete or masonry retaining walls having a maximum height of 24 feet. In the event that walls significantly higher than 24 feet are planned, Geocon should be contacted for additional recommendations. 7.11.2 Retaining wall foundations may be designed in accordance with the recommendations provided in the Foundation Design section of this report (see Section 7.5). 7.11.3 Retaining walls with a level backfill surface that are not restrained at the top should be designed utilizing a triangular distribution of pressure (active pressure). Restrained walls are those that are not allowed to rotate more than 0.001H (where H equals the height of the retaining portion of the wall in feet) at the top of the wall. Where walls are restrained from movement at the top, walls may be designed utilizing a triangular distribution of pressure (at-rest pressure). The table below presents recommended pressures to be used in retaining wall design, assuming that proper drainage will be maintained. RETAINING WALL WITH LEVEL BACKFILL SURFACE HEIGHT OF RETAINING WALL (Feet) ACTIVE PRESSURE EQUIVALENT FLUID PRESSURE (Pounds Per Cubic Foot) AT-REST PRESSURE EQUIVALENT FLUID PRESSURE (Pounds Per Cubic Foot) Up to 13 34 48 14-24 46 50 Geocon Project No. W1304-06-01 - 21 - September 19, 2023 7.11.4 The wall pressures provided above assume that the proposed retaining walls will support relatively undisturbed alluvial soils. If sloping techniques are to be utilized for construction of proposed walls, which would result in a wedge of engineered fill behind the retaining walls, revised earth pressures may be required. This should be evaluated once the use of sloping measures is established and once the geotechnical characteristics of the engineered backfill soils can be further evaluated. 7.11.5 The wall pressures provided above assume that the retaining wall will be properly drained preventing the buildup of hydrostatic pressure. If retaining wall drainage is not implemented, the equivalent fluid pressure to be used in design of undrained walls is 90 pcf. The value includes hydrostatic pressures plus buoyant lateral earth pressures. 7.11.6 Additional active pressure should be added for a surcharge condition due to sloping ground, vehicular traffic or adjacent structures and should be designed for each condition as the project progresses. 7.11.7 It is recommended that line-load surcharges from adjacent wall footings, use horizontal pressures generated from NAV-FAC DM 7.2. The governing equations are: 𝐹𝑜𝑟 𝑥𝐻ൗ ≤0.4 𝜎ுሺ𝑧ሻ =0.20 × ቀ𝑧𝐻ቁ ൤0.16 +ቀ𝑧𝐻ቁଶ൨ ଶ × 𝑄௅ 𝐻 and 𝐹𝑜𝑟 𝑥𝐻ൗ >0.4 𝜎ுሺ𝑧ሻ =1.28 × ቀ𝑥𝐻ቁଶ × ቀ𝑧𝐻ቁ ൤ቀ𝑥 𝐻ቁଶ +ቀ𝑧 𝐻ቁଶ൨ଶ × 𝑄௅ 𝐻 where x is the distance from the face of the excavation or wall to the vertical line-load, H is the distance from the bottom of the footing to the bottom of excavation or wall, z is the depth at which the horizontal pressure is desired, QL is the vertical line-load and σH(z) is the horizontal pressure at depth z. Geocon Project No. W1304-06-01 - 22 - September 19, 2023 7.11.8 It is recommended that vertical point-loads, from construction equipment outriggers or adjacent building columns use horizontal pressures generated from NAV-FAC DM 7.2. The governing equations are: 𝐹𝑜𝑟 𝑥𝐻ൗ ≤0.4 𝜎ு(𝑧)=0.28 × ቀ 𝑧 𝐻ቁଶ ൤0.16 +ቀ𝑧 𝐻ቁଶ൨ ଷ × 𝑄௉ 𝐻ଶ and 𝐹𝑜𝑟 𝑥𝐻ൗ >0.4 𝜎ு(𝑧)=1.77 × ቀ𝑥𝐻ቁଶ × ቀ𝑧𝐻ቁଶ ൤ቀ𝑥𝐻ቁଶ +ቀ𝑧𝐻ቁଶ൨ ଷ × 𝑄௉ 𝐻ଶ then 𝜎ᇱு (𝑧)= 𝜎ு(𝑧)𝑐𝑜𝑠ଶ (1.1𝜃) where x is the distance from the face of the excavation/wall to the vertical point-load, H is distance from the outrigger/bottom of column footing to the bottom of excavation, z is the depth at which the horizontal pressure is desired, Qp is the vertical point-load, σH(z) is the horizontal pressure at depth z, ϴ is the angle between a line perpendicular to the excavation/wall and a line from the point-load to location on the excavation/wall where the surcharge is being evaluated, and σH(z) is the horizontal pressure at depth z. 7.11.9 In addition to the recommended earth pressure, the upper 10 feet of the retaining wall adjacent to the street or driveway areas should be designed to resist a uniform lateral pressure of 100 psf, acting as a result of an assumed 300 psf surcharge behind the wall due to normal street traffic. If the traffic is kept back at least 10 feet from the wall, the traffic surcharge may be neglected. 7.11.10 Seismic lateral forces should be incorporated into the design as necessary, and recommendations for seismic lateral forces are presented below. 7.12 Dynamic (Seismic) Lateral Forces 7.12.1 The structural engineer should determine the seismic design category for the project in accordance with Section 1613 of the CBC. If the project possesses a seismic design category of D, E, or F, proposed retaining walls in excess of 6 feet in height should be designed with seismic lateral pressure (Section 1803.5.12 of the 2019 CBC). Geocon Project No. W1304-06-01 - 23 - September 19, 2023 7.12.2 A seismic load of 10 pcf should be used for design of walls that support more than 6 feet of backfill in accordance with Section 1803.5.12 of the 2019 CBC. The seismic load is applied as an equivalent fluid pressure along the height of the wall and the calculated loads result in a maximum load exerted at the base of the wall and zero at the top of the wall. This seismic load should be applied in addition to the active earth pressure. The earth pressure is based on half of two-thirds of PGAM calculated from ASCE 7-16 Section 11.8.3. 7.13 Retaining Wall Drainage 7.13.1 Unless designed for hydrostatic pressures, retaining walls should be provided with a drainage system. At the base of the drain system, a subdrain covered with a minimum of 12 inches of gravel should be installed, and a compacted fill blanket or other seal placed at the surface (see Figure 5). The clean bottom and subdrain pipe, behind a retaining wall, should be observed by the Geotechnical Engineer (a representative of Geocon), prior to placement of gravel or compacting backfill. 7.13.2 As an alternative, a plastic drainage composite such as Miradrain or equivalent may be installed in continuous, 4-foot wide columns along the entire back face of the wall, at 8 feet on center. The top of these drainage composite columns should terminate approximately 18 inches below the ground surface, where either hardscape or a minimum of 18 inches of relatively cohesive material should be placed as a cap (see Figure 6). These vertical columns of drainage material would then be connected at the bottom of the wall to a collection panel or a 1-cubic-foot rock pocket drained by a 4-inch subdrain pipe. 7.13.3 Subdrainage pipes at the base of the retaining wall drainage system should outlet to an acceptable location via controlled drainage structures. Drainage should not be allowed to flow uncontrolled over descending slopes. 7.13.4 Moisture affecting below grade walls is one of the most common post-construction complaints. Poorly applied or omitted waterproofing can lead to efflorescence or standing water. Particular care should be taken in the design and installation of waterproofing to avoid moisture problems, or actual water seepage into the structure through any normal shrinkage cracks which may develop in the concrete walls, floor slab, foundations and/or construction joints. The design and inspection of the waterproofing is not the responsibility of the geotechnical engineer. A waterproofing consultant should be retained in order to recommend a product or method, which would provide protection to subterranean walls, floor slabs and foundations. Geocon Project No. W1304-06-01 - 24 - September 19, 2023 7.14 Elevator Pit Design 7.14.1 The elevator pit slab and retaining wall should be designed by the project structural engineer. Elevator pit walls may be designed in accordance with the recommendations in the Mat Foundation Design and Retaining Wall Design sections of this report (see Sections 7.5 and 7.11). 7.14.2 Additional active pressure should be added for a surcharge condition due to sloping ground, vehicular traffic or adjacent foundations and should be designed for each condition as the project progresses. 7.14.3 If retaining wall drainage is to be provided, the drainage system should be designed in accordance with the Retaining Wall Drainage section of this report (see Section 7.13) 7.14.4 It is suggested that the exterior walls and slab be waterproofed to prevent excessive moisture inside of the elevator pit. Waterproofing design and installation is not the responsibility of the geotechnical engineer. 7.15 Elevator Piston 7.15.1 If a plunger-type elevator piston is installed for this project, a deep drilled excavation will be required. It is important to verify that the drilled excavation is not situated immediately adjacent to a foundation or shoring pile, or the drilled excavation could compromise the existing foundation support or pile support, especially if the drilling is performed subsequent to the foundation or pile construction. 7.15.2 Casing will be required since caving is expected in the drilled excavation, and the contractor should be prepared to use casing and should have it readily available at the commencement of drilling activities. Continuous observation of the drilling and installation of the elevator piston by the Geotechnical Engineer (a representative of Geocon West, Inc.) is required. 7.15.3 The annular space between the piston casing and drilled excavation wall should be filled with a minimum of 1½-sack slurry pumped from the bottom up. As an alternative, pea gravel may be utilized. The use of soil to backfill the annular space is not acceptable. Geocon Project No. W1304-06-01 - 25 - September 19, 2023 7.16 Temporary Excavations 7.16.1 Excavations up to 26 feet in height are anticipated for excavation and construction of the proposed subterranean levels and foundation system. The excavations are expected to expose artificial fill and alluvial soils, which are subject to excessive caving where granular soils are encountered. Vertical excavations up to 5 feet in height may be attempted where loose soils or caving sands are not present, and where not surcharged by adjacent traffic or structures. 7.16.2 Vertical excavations greater than 5 feet or where surcharged by existing structures will require sloping or shoring measures in order to provide a stable excavation. Where sufficient space is available, temporary unsurcharged embankments could be sloped back at a uniform 1:1 slope gradient or flatter up to maximum height of 12 feet. A uniform slope does not have a vertical portion. Where space is limited, shoring measures will be required. Shoring data is provided in Section 7.17 of this report. 7.16.3 Where temporary construction slopes are utilized, the top of the slope should be barricaded to prevent vehicles and storage loads at the top of the slope within a horizontal distance equal to the height of the slope. If the temporary construction slopes are to be maintained during the rainy season, berms are suggested along the tops of the slopes where necessary to prevent runoff water from entering the excavation and eroding the slope faces. Geocon personnel should inspect the soils exposed in the cut slopes during excavation so that modifications of the slopes can be made if variations in the soil conditions occur. All excavations should be stabilized within 30 days of initial excavation. 7.17 Shoring – Soldier Pile Design and Installation 7.17.1 The following information on the design and installation of shoring is preliminary. Review of the final shoring plans and specifications should be made by this office prior to bidding or negotiating with a shoring contractor. 7.17.2 One method of shoring would consist of steel soldier piles, placed in drilled holes and backfilled with concrete. The steel soldier piles may also be installed utilizing high frequency vibration. Where maximum excavation heights are less than 12 feet the soldier piles are typically designed as cantilevers. Where excavations exceed 12 feet or are surcharged, soldier piles may require lateral bracing utilizing drilled tie-back anchors or raker braces to maintain an economical steel beam size and prevent excessive deflection. The size of the steel beam, the need for lateral bracing, and the acceptable shoring deflection should be determined by the project shoring engineer. Geocon Project No. W1304-06-01 - 26 - September 19, 2023 7.17.3 The design embedment of the shoring pile toes must be maintained during excavation activities. The toes of the perimeter shoring piles should be deepened to take into account any required excavations necessary for foundation excavations and/or adjacent drainage systems. 7.17.4 The proposed soldier piles may also be designed as permanent piles. The required pile depths, dimensions, and spacing should be determined and designed by the project structural and shoring engineers. All piles utilized for shoring can also be incorporated into a permanent retaining wall system (shotcrete wall) and should be designed in accordance with the earth pressure provided in the Retaining Wall Design section of this report (see Section 7.11). 7.17.5 Drilled cast-in-place soldier piles should be placed no closer than 3 diameters on center. The minimum diameter of the piles is 18 inches. Structural concrete should be used for the soldier piles below the excavation; lean-mix concrete may be employed above that level. As an alternative, lean-mix concrete may be used throughout the pile where the reinforcing consists of a wideflange section. The slurry must be of sufficient strength to impart the lateral bearing pressure developed by the wideflange section to the soil. For design purposes, an allowable passive value for the soils below the bottom plane of excavation may be assumed to be 330 psf per foot. Where piles are installed by vibration techniques, the passive pressure may be assumed to mobilize across a width equal to the two times the dimension of the beam flange. The allowable passive value may be doubled for isolated piles spaced a minimum of three times the pile diameter. To develop the full lateral value, provisions should be implemented to assure firm contact between the soldier piles and the undisturbed alluvium. Geocon Project No. W1304-06-01 - 27 - September 19, 2023 7.17.6 Groundwater was not encountered during site exploration. However, groundwater levels can fluctuate and may be different at the time of construction. It is not uncommon for groundwater or seepage conditions to develop where none previously existed. Therefore, the contractor should be prepared for groundwater during pile installation should the need arise. If more than 6 inches of water is present in the bottom of the excavation, a tremie is required to place the concrete into the bottom of the hole. A tremie should consist of a rigid, water-tight tube having a diameter of not less than 6 inches with a hopper at the top. The tube should be equipped with a device that will close the discharge end and prevent water from entering the tube while it is being charged with concrete. The tremie should be supported so as to permit free movement of the discharge end over the entire top surface of the work and to permit rapid lowering when necessary to retard or stop the flow of concrete. The discharge end should be closed at the start of the work to prevent water entering the tube and should be entirely sealed at all times, except when the concrete is being placed. The tremie tube should be kept full of concrete. The flow should be continuous until the work is completed, and the resulting concrete seal should be monolithic and homogeneous. The tip of the tremie tube should always be kept about 5 feet below the surface of the concrete and definite steps and safeguards should be taken to ensure that the tip of the tremie tube is never raised above the surface of the concrete. 7.17.7 A special concrete mix should be used for concrete to be placed below water. The design should provide for concrete with an unconfined compressive strength pounds per square inch (psi) of 1,000 psi over the initial job specification. An admixture that reduces the problem of segregation of paste/aggregates and dilution of paste should be included. The slump should be commensurate to any research report for the admixture, provided that it should also be the minimum for a reasonable consistency for placing when water is present. 7.17.8 Casing will be required since caving is expected, and the contractor should have casing available prior to commencement of drilling activities When casing is used, extreme care should be employed so that the pile is not pulled apart as the casing is withdrawn. At no time should the distance between the surface of the concrete and the bottom of the casing be less than 5 feet. As an alternative, piles may be vibrated into place; however, there is always a risk that excessive vibrations in sandy soils could induce settlements and distress to adjacent offsite improvements. Continuous observation of the drilling and pouring of the piles by the Geotechnical Engineer (a representative of Geocon West, Inc.), is required. 7.17.9 If a vibratory method of solider pile installation is utilized, predrilling may be performed prior to installation of the steel beams. If predrilling is performed, it is recommended that the bore diameter be at least 2 inches smaller than the largest dimension of the pile to prevent excessive loss in the frictional component of the pile capacity. Predrilling should not be conducted below the proposed excavation bottom. Geocon Project No. W1304-06-01 - 28 - September 19, 2023 7.17.10 If a vibratory method is utilized, the owner should be aware of the potential risks associated with vibratory efforts, which typically involve inducing settlement within the vicinity of the pile which could result in a potential for damage to existing improvements in the area. 7.17.11 The level of vibration that results from the installation of the piles should not exceed a threshold where occupants of nearby structures are disturbed, despite higher vibration tolerances that a building may endure without deformation or damage. The main parameter used for vibration assessment is peak particle velocity in units of inch per second (in/sec). The acceptable range of peak particle velocity should be evaluated based on the age and condition of adjacent structures, as well as the tolerance of human response to vibration. 7.17.12 Based on Table 19 of the Transportation and Construction Induced Vibration Guidance Manual (Caltrans 2013), a continuous source of vibrations (ex. vibratory pile driving) which generates a maximum peak particle velocity of 0.5 in/sec is considered tolerable for modern industrial/commercial buildings and new residential structures. The Client should be aware that a lower value may be necessary if older or fragile structures are in the immediate vicinity of the site. 7.17.13 Vibrations should be monitored and record with seismographs during pile installation to detect the magnitude of vibration and oscillation experienced by adjacent structures. If the vibrations exceed the acceptable range during installation, the shoring contractor should modify the installation procedure to reduce the values to within the acceptable range. Vibration monitoring is not the responsibility of the Geotechnical Engineer. 7.17.14 Geocon does not practice in the field of vibration monitoring. If construction techniques will be implemented, it is recommended that qualified consultant be retained to provide site specific recommendations for vibration thresholds and monitoring. 7.17.15 The frictional resistance between the soldier piles and retained soil may be used to resist the vertical component of the load. The coefficient of friction may be taken as 0.40 based on uniform contact between the steel beam and lean-mix concrete and retained earth. The portion of soldier piles below the plane of excavation may also be employed to resist the downward loads. The downward capacity may be determined using a frictional resistance of 475 psf per foot. 7.17.16 Due to the nature of the site soils, it is expected that continuous lagging between soldier piles will be required. However, it is recommended that the exposed soils be observed by the Geotechnical Engineer (a representative of Geocon West, Inc.), to verify the presence of any competent, cohesive soils and the areas where lagging may be omitted. Geocon Project No. W1304-06-01 - 29 - September 19, 2023 7.17.17 The time between lagging excavation and lagging placement should be as short as possible soldier piles should be designed for the full-anticipated pressures. Due to arching in the soils, the pressure on the lagging will be less. It is recommended that the lagging be designed for the full design pressure but be limited to a maximum of 400 psf. 7.17.18 For the design of unbraced shoring, it is recommended that an equivalent fluid pressure be utilized for design. A trapezoidal distribution of lateral earth pressure may be used where shoring will be restrained by bracing or tie backs. The recommended active and trapezoidal pressure are provided in the following table. A diagram depicting the trapezoidal pressure distribution of lateral earth pressure is provided below the table. HEIGHT OF SHORING (FEET) EQUIVALENT FLUID PRESSURE (Pounds Per Cubic Foot) (ACTIVE PRESSURE) EQUIVALENT FLUID PRESSURE Trapezoidal (Where H is the height of the shoring in feet) Up to 15 27 17H 16-26 39 24H 7.17.19 Where a combination of sloped embankment and shoring is utilized, the pressure will be greater and must be determined for each combination. Additional active pressure should be added for a surcharge condition due to sloping ground, vehicular traffic, or adjacent structures and must be determined for each combination. Trapezoidal Distribution of Pressure H 0.2H 0.2H 0.6H Geocon Project No. W1304-06-01 - 30 - September 19, 2023 7.17.20 It is recommended that line-load surcharges from adjacent wall footings, use horizontal pressures generated from NAV-FAC DM 7.2. The governing equations are: 𝐹𝑜𝑟 𝑥𝐻ൗ ≤0.4 𝜎ு(𝑧)=0.20 × ቀ𝑧 𝐻ቁ ൤0.16 +ቀ𝑧 𝐻ቁଶ൨ ଶ × 𝑄௅ 𝐻 and 𝐹𝑜𝑟 𝑥𝐻ൗ >0.4 𝜎ு(𝑧)=1.28 × ቀ𝑥𝐻ቁଶ × ቀ𝑧𝐻ቁ ൤ቀ𝑥𝐻ቁଶ +ቀ𝑧𝐻ቁଶ൨ ଶ × 𝑄௅ 𝐻 where x is the distance from the face of the excavation or wall to the vertical line-load, H is the distance from the bottom of the footing to the bottom of excavation or wall, z is the depth at which the horizontal pressure is desired, QL is the vertical line-load and σH(z) is the horizontal pressure at depth z. 7.17.21 It is recommended that vertical point-loads, from construction equipment outriggers or adjacent building columns use horizontal pressures generated from NAV-FAC DM 7.2. The governing equations are: 𝐹𝑜𝑟 𝑥𝐻ൗ ≤0.4 𝜎ு(𝑧)=0.28 × ቀ 𝑧𝐻ቁଶ ൤0.16 +ቀ𝑧𝐻ቁଶ൨ ଷ × 𝑄௉ 𝐻ଶ and 𝐹𝑜𝑟 𝑥𝐻ൗ >0.4 𝜎ு(𝑧)=1.77 × ቀ𝑥 𝐻ቁଶ × ቀ𝑧 𝐻ቁଶ ൤ቀ𝑥 𝐻ቁଶ +ቀ𝑧 𝐻ቁଶ൨ ଷ × 𝑄௉ 𝐻ଶ then 𝜎ᇱு (𝑧)= 𝜎ு(𝑧)𝑐𝑜𝑠ଶ (1.1𝜃) where x is the distance from the face of the excavation/wall to the vertical point-load, H is distance from the outrigger/bottom of column footing to the bottom of excavation, z is the depth at which the horizontal pressure is desired, Qp is the vertical point-load, σH(z) is the horizontal pressure at depth z, ϴ is the angle between a line perpendicular to the excavation/wall and a line from the point-load to location on the excavation/wall where the surcharge is being evaluated, and σH(z) is the horizontal pressure at depth z. Geocon Project No. W1304-06-01 - 31 - September 19, 2023 7.17.22 In addition to the recommended earth pressure, the upper 10 feet of the shoring adjacent to the street or driveway areas should be designed to resist a uniform lateral pressure of 100 psf, acting as a result of an assumed 300 psf surcharge behind the shoring due to normal street traffic. If the traffic is kept back at least 10 feet from the shoring, the traffic surcharge may be neglected. 7.17.23 It is difficult to accurately predict the amount of deflection of a shored embankment. It should be realized that some deflection will occur. It is recommended that the deflection be minimized to prevent damage to existing structures and adjacent improvements. Where public rights-of-way are present or adjacent offsite structures do not surcharge the shoring excavation, the shoring deflection should be limited to less than 1 inch at the top of the shored embankment. Where offsite structures are within the shoring surcharge area it is recommended that the beam deflection be limited to less than ½ inch at the elevation of the adjacent offsite foundation, and no deflection at all if deflections will damage existing structures. The allowable deflection is dependent on many factors, such as the presence of structures and utilities near the top of the embankment, and will be assessed and designed by the project shoring engineer. 7.17.24 Because of the depth of the excavation, some means of monitoring the performance of the shoring system is suggested. The monitoring should consist of periodic surveying of the lateral and vertical locations of the tops of all soldier piles and the lateral movement along the entire lengths of selected soldier piles. 7.17.25 Due to the depth of the excavation and proximity to adjacent structures, it is suggested that prior to excavation the existing improvements be inspected, and their present condition be documented. For documentation purposes, photographs should be taken of preconstruction distress conditions and level surveys of adjacent grade and pavement should be considered. During excavation activities, the adjacent structures and pavement should be periodically inspected for signs of distress. In the event that distress or settlement is observed, an investigation should be performed, and corrective measures taken so that continued or worsened distress or settlement is mitigated. Documentation and monitoring of the offsite structures and improvements is not the responsibility of the geotechnical engineer. 7.18 Temporary Tie-Back Anchors 7.18.1 Temporary tie-back anchors may be used with the solider pile wall system to resist lateral loads. Post-grouted friction anchors are recommended. For design purposes, it may be assumed that the active wedge adjacent to the shoring is defined by a plane drawn 35 degrees with the vertical through the bottom plane of the excavation. Friction anchors should extend a minimum of 20 feet beyond the potentially active wedge and to greater lengths if necessary to develop the desired capacities. The locations and depths of all offsite utilities should be thoroughly checked and incorporated into the drilling angle design for the tie-back anchors. Geocon Project No. W1304-06-01 - 32 - September 19, 2023 7.18.2 The capacities of the anchors should be determined by testing of the initial anchors as outlined in a following section. Only the frictional resistance developed beyond the active wedge would be effective in resisting lateral loads. Anchors should be placed at least 6 feet on center to be considered isolated. For preliminary design purposes, it is estimated that drilled friction anchors constructed without utilizing post-grouting techniques will develop average skin frictions as follows: • 7 feet below the top of the excavation – 880 pounds per square foot • 15 feet below the top of the excavation – 1,500 pounds per square foot 7.18.3 Depending on the techniques utilized, and the experience of the contractor performing the installation, a maximum allowable friction capacity of 3.2 kips per linear foot for post-grouted anchors (for a minimum 20-foot length beyond the active wedge) may be assumed for design purposes. Only the frictional resistance developed beyond the active wedge should be utilized in resisting lateral loads. Higher capacities may be possible but must be verified by testing. 7.19 Anchor Installation 7.19.1 Tie-back anchors are typically installed between 20 and 40 degrees below the horizontal; however, occasionally alternative angles are necessary to avoid existing improvements and utilities. The locations and depths of all offsite utilities should be thoroughly checked prior to design and installation of the tie-back anchors. Caving of the anchor shafts, particularly within sand and gravel deposits or seepage zones, should be anticipated during installation and provisions should be implemented in order to minimize such caving. It is suggested that hollow-stem auger drilling equipment be used to install the anchors. The anchor shafts should be filled with concrete by pumping from the tip out, and the concrete should extend from the tip of the anchor to the active wedge. In order to minimize the chances of caving, it is recommended that the portion of the anchor shaft within the active wedge be backfilled with sand before testing the anchor. This portion of the shaft should be filled tightly and flush with the face of the excavation. The sand backfill should be placed by pumping; the sand may contain a small amount of cement to facilitate pumping. 7.20 Anchor Testing 7.20.1 All of the anchors should be tested to at least 150 percent of design load. The total deflection during this test should not exceed 12 inches. The rate of creep under the 150 percent test load should not exceed 0.1 inch over a 15-minute period in order for the anchor to be approved for the design loading. Geocon Project No. W1304-06-01 - 33 - September 19, 2023 7.20.2 At least 10 percent of the anchors should be selected for "quick" 200 percent tests and three additional anchors should be selected for 24-hour 200 percent tests. The purpose of the 200 percent tests is to verify the friction value assumed in design. The anchors should be tested to develop twice the assumed friction value. These tests should be performed prior to installation of additional tiebacks. Where satisfactory tests are not achieved on the initial anchors, the anchor diameter and/or length should be increased until satisfactory test results are obtained. 7.20.3 The total deflection during the 24-hour 200 percent test should not exceed 12 inches. During the 24-hour tests, the anchor deflection should not exceed 0.75 inches measured after the 200 percent test load is applied. 7.20.4 For the "quick" 200 percent tests, the 200 percent test load should be maintained for 30 minutes. The total deflection of the anchor during the 200 percent quick tests should not exceed 12 inches; the deflection after the 200 percent load has been applied should not exceed 0.25 inch during the 30-minute period. 7.20.5 After a satisfactory test, each anchor should be locked-off at the design load. This should be verified by rechecking the load in the anchor. The load should be within 10 percent of the design load. A representative of this firm should observe the installation and testing of the anchors. 7.21 Internal Bracing 7.21.1 Rakers may be utilized to brace the soldier piles in lieu of tieback anchors. The raker bracing could be supported laterally by temporary concrete footings (deadmen) or by the permanent, interior footings. For design of such temporary footings or deadmen, poured with the bearing surface normal to rakers inclined at 45 degrees, a bearing value of 2,000 psf may be used, provided the shallowest point of the footing is at least one foot below the lowest adjacent grade. The structural engineer should review the shoring plans to determine if raker footings conflict with the structural foundation system. The client should be aware that the utilization of rakers could significantly impact the construction schedule due to their intrusion into the construction site and potential interference with equipment. Geocon Project No. W1304-06-01 - 34 - September 19, 2023 7.22 Stormwater Infiltration 7.22.1 During the site exploration, boring B4 was utilized to perform percolation testing. The boring was advanced to the depth listed in the table below. Slotted casing was placed in the boring, and the annular space between the casing and excavation was filled with filter pack. The boring was then filled with water to pre-saturate the soils. On February 9, 2021, after pre-saturating the soils, the casing was refilled with water and percolation test readings were performed after repeated flooding of the cased excavation. Based on the test results, the measured percolation rate and design infiltration rate, for the earth materials encountered, are provided in the following table. Percolation test field data and calculation of the measured percolation rate and design infiltration rate are provided on Figures 7. Boring Soil Type Infiltration Depth (ft) Measured Percolation Rate (in / hour) Design Infiltration Rate (in / hour) B4 SW 20-30½ 13.83 6.92 7.22.2 Based on the test method utilized (Boring Percolation Test), the reduction factor RFt may be taken as 2.0 in the infiltration system design. Based on the number of tests performed and consistency of the soils throughout the site, it is suggested that the reduction factor RFv be taken as 1.0. In addition, provided proper maintenance is performed to minimize long-term siltation and plugging, the reduction factor RFs may be taken as 1.0. 7.22.3 The results of the percolation testing in the table above indicate that the infiltration rate for soils encountered at the depth and location indicated in the table above are considered conductive to infiltration, and it is our opinion that the site is suitable for infiltration of stormwater. 7.22.4 It is our further opinion that infiltration of stormwater and will not induce excessive hydro-consolidation, will not create a perched groundwater condition, will not affect soil structure interaction of existing or proposed foundations due to expansive soils, will not saturate soils supported by existing retaining walls, and will not increase the potential for liquefaction. Resulting settlements are anticipated to be less than ¼ inch, if any. If infiltration is planned for any location other than where the above testing was performed, additional field and laboratory testing may be required. 7.22.5 The infiltration system must be located such that the closest distance between an adjacent foundation is at least 15 feet in all directions from the zone of saturation. The zone of saturation may be assumed to project downward from the discharge of the infiltration facility at a gradient of 1:1. Additional property line or foundation setbacks may be required by the governing jurisdiction and should be incorporated into the stormwater infiltration system design as necessary. Geocon Project No. W1304-06-01 - 35 - September 19, 2023 7.22.6 Where a 15-foot horizontal setback cannot be maintained between the infiltration system and an adjacent footing, and the infiltration system penetrates below the foundation influence line, the proposed stormwater infiltration system must be designed to resist the surcharge from the adjacent foundation. The foundation surcharge line may be assumed to project down away from the bottom of the foundation at a 1:1 gradient 7.22.7 Subsequent to the placement of the infiltration system, it is acceptable to backfill the resulting void space between the excavation sidewalls and the infiltration system with minimum 2-sack slurry provided the slurry is not placed in the infiltration zone. It is recommended that pea gravel be utilized adjacent to the infiltration zone so communication of water to the soil is not hindered. 7.22.8 The design drawings should be reviewed and approved by the Geotechnical Engineer. The installation of the stormwater infiltration system should be observed and approved in writing by the Geotechnical Engineer (a representative of Geocon). 7.23 Surface Drainage 7.23.1 Proper surface drainage is critical to the future performance of the project. Uncontrolled infiltration of irrigation excess and storm runoff into the soils can adversely affect the performance of the planned improvements. Saturation of a soil can cause it to lose internal shear strength and increase its compressibility, resulting in a change in the original designed engineering properties. Proper drainage should be maintained at all times. 7.23.2 All site drainage should be collected and controlled in non-erosive drainage devices. Drainage should not be allowed to pond anywhere on the site, and especially not against any foundation or retaining wall. The site should be graded and maintained such that surface drainage is directed away from structures in accordance with 2019 CBC 1804.4 or other applicable standards. In addition, drainage should not be allowed to flow uncontrolled over any descending slope. Discharge from downspouts, roof drains and scuppers are not recommended onto unprotected soils within 5 feet of the building perimeter. Planters which are located adjacent to foundations should be sealed to prevent moisture intrusion into the soils providing foundation support. Landscape irrigation is not recommended within 5 feet of the building perimeter footings except when enclosed in protected planters. 7.23.3 Positive site drainage should be provided away from structures, pavement, and the tops of slopes to swales or other controlled drainage structures. The building pad and pavement areas should be fine graded such that water is not allowed to pond. Geocon Project No. W1304-06-01 - 36 - September 19, 2023 7.23.4 Landscaping planters immediately adjacent to paved areas are not recommended due to the potential for surface or irrigation water to infiltrate the pavement's subgrade and base course. Either a subdrain, which collects excess irrigation water and transmits it to drainage structures, or an impervious above-grade planter boxes should be used. In addition, where landscaping is planned adjacent to the pavement, it is recommended that consideration be given to providing a cutoff wall along the edge of the pavement that extends at least 12 inches below the base material. 7.24 Plan Review 7.24.1 Grading, foundation, and shoring plans should be reviewed by the Geotechnical Engineer (a representative of Geocon West, Inc.), prior to finalization to verify that the plans have been prepared in substantial conformance with the recommendations of this report and to provide additional analyses or recommendations. Geocon Project No. W1304-06-01 September 19, 2023 LIMITATIONS AND UNIFORMITY OF CONDITIONS 1. The recommendations of this report pertain only to the site investigated and are based upon the assumption that the soil conditions do not deviate from those disclosed in the investigation. If any variations or undesirable conditions are encountered during construction, or if the proposed construction will differ from that anticipated herein, Geocon West, Inc. should be notified so that supplemental recommendations can be given. The evaluation or identification of the potential presence of hazardous or corrosive materials was not part of the scope of services provided by Geocon West, Inc. 2. This report is issued with the understanding that it is the responsibility of the owner, or of his representative, to ensure that the information and recommendations contained herein are brought to the attention of the architect and engineer for the project and incorporated into the plans, and the necessary steps are taken to see that the contractor and subcontractors carry out such recommendations in the field. 3. The findings of this report are valid as of the date of this report. However, changes in the conditions of a property can occur with the passage of time, whether they are due to natural processes or the works of man on this or adjacent properties. In addition, changes in applicable or appropriate standards may occur, whether they result from legislation or the broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by changes outside our control. Therefore, this report is subject to review and should not be relied upon after a period of three years. 4. The firm that performed the geotechnical investigation for the project should be retained to provide testing and observation services during construction to provide continuity of geotechnical interpretation and to check that the recommendations presented for geotechnical aspects of site development are incorporated during site grading, construction of improvements, and excavation of foundations. If another geotechnical firm is selected to perform the testing and observation services during construction operations, that firm should prepare a letter indicating their intent to assume the responsibilities of project geotechnical engineer of record. A copy of the letter should be provided to the regulatory agency for their records. In addition, that firm should provide revised recommendations concerning the geotechnical aspects of the proposed development, or a written acknowledgement of their concurrence with the recommendations presented in our report. They should also perform additional analyses deemed necessary to assume the role of Geotechnical Engineer of Record. Geocon Project No. W1304-06-01 September 19, 2023 LIST OF REFERENCES Arcadia, City of, 2010, Chapter 8: Safety Element, Arcadia General Plan. California Division of Mines and Geology, 1999, State of California Seismic Hazard Zones, Mount Wilson Quadrangle, Official Map Released March 25, 1999. California Division of Mines and Geology, 1998, Seismic Hazard Evaluation of the Mount Wilson 7.5-Minute Quadrangle, Los Angeles County, California, Open File Report 98-21. California Geologic Energy Management Division, 2021, CalGEM Resources Well Finder, http://maps.conservation.ca.gov.doggr/index.html#close. California Geological Survey, 2021a, CGS Information Warehouse, Regulatory Map Portal, http://maps.conservation.ca.gov/cgs/informationwarehouse/index.html?map=regulatorymaps. California Geological Survey, 2021b, Earthquake Zones of Required Investigation, https://maps.conservation.ca.gov/cgs/EQZApp/app/. California Geological Survey, 2018, Earthquake Fault Zones, A Guide for Government Agencies, Property Owners/Developers, and Geoscience Practitioners for Assessing Fault Rupture Hazards in California, Special Publication 42, Revised 2018. California Geological Survey, 2017, Zones of Required Investigations, Mount Wilson Quadrangle, Revised Official Map, dated June 15, 2017. California Geological Survey, 2016, The Raymond Fault in the Mt. Wilson and El Monte Quadrangles, Los Angeles County, California, Fault Evaluation Report FER-264, by Jerome A. Treiman, dated December 7, 2016. California Geological Survey, 2010, Geologic Compilation of Quaternary Surficial Deposits in Southern California, San Gabriel River Hydrogeologic Unit, A Project for the Department of Water Resources by the California Geological Survey, Plate 15, CGS Special Report 217, dated July 2010. Crook, R., Jr., Allen, C. R., Kamb, B., Payne, C. M., and Proctor, R. J., 1987, Recent Reverse Faulting in the Transverse Ranges, California, U.S. Geological Survey Professional Paper 1339. FEMA, 2021, Online Flood Hazard Maps, http://www.esri.com/hazards/index.html. Jennings, C. W. and Bryant, W. A., 2010, Fault Activity Map of California, California Geological Survey Geologic Data Map No. 6. Leighton and Associates, Inc., 1990, Technical Appendix to the Safety Element of the Los Angeles County General Plan, Hazard Reduction in Los Angeles County. Los Angeles County Department of Public Works, 2021a, Ground Water Wells Website, http://dpw2.co.la.ca.us/website/wells/viewer.asp. Los Angeles County Department of Public Works, 2021b, Flood Zone Determination Website, http://dpw.lacounty.gov/apps/wmd/floodzone/map.htm. Geocon Project No. W1304-06-01 September 19, 2023 LIST OF REFERENCES (Continued) Toppozada, T., Branum, D., Petersen, M, Hallstrom, C., and Reichle, M., 2000, Epicenters and Areas Damaged by M> 5 California Earthquakes, 1800 – 1999, California Geological Survey, Map Sheet 49. U.S. Geological Survey and California Geological Survey, 2006, Quaternary Fault and Fold Database for the United States, accessed March 5, 2021 from USGS web site: http//earthquake.usgs.gov/hazards/qfaults/. Ziony, J. I., and Jones, L. M., 1989, Map Showing Late Quaternary Faults and 1978–1984 Seismicity of the Los Angeles Region, California, U.S. Geological Survey Miscellaneous Field Studies Map MF-1964. REFERENCE: U.S.G.S. TOPOGRAPHIC MAPS, 7.5 MINUTE SERIES, MT. WILSON, CA QUADRANGLE LATITUDE: 34.141703 LONGTITUDE: -118.030544 FIG. 1 VICINITY MAP CHECKED BY: SFKDRAFTED BY: RA PROJECT NO. W1304-06-01SEPT 2023 34 EAST SANTA CLARA STREET ARCADIA, CALIFORNIA SITE ENVIRONMENTAL GEOTECHNICAL MATERIALS 500 NORTH VICTORY BOULEVARD - BURBANK, CA 91502 PHONE (818) 841-8388 - FAX (818) 841-1704 0 100' SITE PLAN FIG. 2APROJECT NO. W1304-06-01SEPT 2023 50' DRAFTED BY: PZ CHECKED BY: JTA LEGEND Approximate Location of Boring B4 Approximate Location of Property LineB1 B2 B4 B3 A A' Location of Existing Structures 34 EAST SANTA CLARA STREET ARCADIA, CALIFORNIA 500 NORTH VICTORY BOULEVARD BURBANK, CA 91502 PHONE (818) 841-8388 - FAX (818) 841-1704 ENVIRONMENTAL GEOTECHNICAL MATERIALS 0 60' CROSS SECTION FIG. 2BPROJECT NO. W1304-06-01SEPT 2023 30' DRAFTED BY: PZ 34 EAST SANTA CLARA STREET ARCADIA, CALIFORNIA CHECKED BY: JTA 500 NORTH VICTORY BOULEVARD BURBANK, CA 91502 PHONE (818) 841-8388 - FAX (818) 841-1704 ENVIRONMENTAL GEOTECHNICAL MATERIALS SITE LATITUDE: 34.141703 LONGTITUDE: -118.030544 0 12 24 Miles Reference: Jennings, C.W. and Bryant, W. A., 2010, Fault Activity Map of California, California Geological Survey Geologic Data Map No. 6. REGIONAL FAULT MAP PROJECT NO. W1304-06-01SEPT 2023 FIG. 3CHECKED BY: SFKDRAFTED BY: RA 34 EAST SANTA CLARA STREET ARCADIA, CALIFORNIA500 NORTH VICTORY BOULEVARD BURBANK, CA 91502 PHONE (818) 841-8388 - FAX (818) 841-1704 ENVIRONMENTAL GEOTECHNICAL MATERIALS SITE DRAFTED BY: RA CHECKED BY: SFK LATITUDE: 34.141703 LONGTITUDE: -118.030544 REGIONAL SEISMICITY MAP FIG. 402040Miles Reference: Toppozada, T., Branum, D., Petersen, M., Hallstrom, C., Cramer, C., and Reichle, M., 2000, Epicenters and Areas Damaged by M>5 California Earthquakes, 1800 - 1999, California Geological Survey, Map Sheet 49.PROJECT NO. W1304-06-01SEPT 2023 34 EAST SANTA CLARA STREET ARCADIA, CALIFORNIA500 NORTH VICTORY BOULEVARD BURBANK, CA 91502 PHONE (818) 841-8388 - FAX (818) 841-1704 ENVIRONMENTAL GEOTECHNICAL MATERIALS 3/4" CRUSHED ROCK MIRAFI 140N OR EQUIVALENT FILTER FABRIC ENVELOPE 4" DIA. PERFORATED ABS OR ADS PIPE - EXTEND TO RETAINING WALL DRAINAGE SYSTEM WATERPROOF WALL PROPERLY COMPACTED BACKFILL GROUND SURFACE FOUNDATION NO SCALE RETAINING WALL DRAIN DETAIL FIG. 5DRAFTED BY: PZ CHECKED BY: JTA PROJECT NO. W1304-06-01SEPT 2023 34 EAST SANTA CLARA STREET ARCADIA, CALIFORNIA ENVIRONMENTAL GEOTECHNICAL MATERIALS 500 NORTH VICTORY BOULEVARD - BURBANK, CA 91502 PHONE (818) 841-8388 - FAX (818) 841-1704 RETAINING WALL FOUNDATION PROPERLY COMPACTED BACKFILL GROUND SURFACE 18" WATER PROOFING BY ARCHITECT DRAINAGE PANEL (J-DRAIN 1000 OR EQUIVALENT) 4" DIA. SCHEDULE 40 PERFORATED PVC PIPE EXTENDED TO APPROVED OUTLET (1 CU. FT./FT.) FILTER FABRIC ENVELOPE 3/4" CRUSHED ROCK MIRAFI 140N OR EQUIVALENT NO SCALE RETAINING WALL DRAIN DETAIL FIG. 6DRAFTED BY: PZ CHECKED BY: JTA PROJECT NO. W1304-06-01SEPT 2023 34 EAST SANTA CLARA STREET ARCADIA, CALIFORNIA ENVIRONMENTAL GEOTECHNICAL MATERIALS 500 NORTH VICTORY BOULEVARD - BURBANK, CA 91502 PHONE (818) 841-8388 - FAX (818) 841-1704 Date: Boring/Test Number: Project Number: Diameter of Boring: 8 inches Project Location: Diameter of Casing: 2 inches Earth Description: Depth of Boring: 30.5 feet Tested By: Depth to Invert of BMP: 20 feet Liquid Description: Depth to Water Table: N/A feet Measurement Method: Depth to Initial Water Depth (d1): 240 inches Start Time for Pre-Soak: Water Remaining in Boring (Y/N): Start Time for Standard: Standard Time Interval Between Readings: 10 Reading Number Time Start (hh:mm) Time End (hh:mm) Elapsed Time time (min) Water Drop During Standard Time Interval, Δd (in) 1 9:40 AM 9:50 AM 10 94.8 2 10:13 AM 10:23 AM 10 93.6 3 10:48 AM 10:58 AM 10 93.6 4 11:21 AM 11:31 AM 10 93.6 5 11:56 AM 12:06 PM 10 93.6 * Calculations Below Based on Stabilized Readings Only Boring Radius, r: 4 inches Test Section Height, h: 79.2 inches A = 2041 in2 Test Section Height, h: 79.2 inches A = 2041 in2 Test Section Height, h: 79.2 inches A = 2041 in2 Reading 6 V = 4705 in3 Percolation Rate = 13.83 inches/hour Reading 7 V = 4705 in3 Percolation Rate = 13.83 inches/hour Reading 8 V = 4705 in3 Percolation Rate = 13.83 inches/hour Measured Percolation Rate = 13.83 inches/hour Reduction Factors Boring Percolation Test, RFt = 2 Site Variability, RFv = 1 Total Reduction Factor = 2 Long Term Siltation, RFs = 1 Design Infiltration Rate Design Infiltration Rate = 6.92 inches/hour Soil Description Notes Comments Stabilized Readings Achieved MEASURED PERCOLATION RATE & DESIGN INFILTRATION RATE CALCULATIONS* 8:05 AM B4 No RA Tuesday, February 9, 2021 12:30 PM BORING PERCOLATION TEST FIELD LOG W1304-06-01 SW Water Sounder 150 N. Santa Anita 𝑇𝑒𝑠𝑡 𝑆𝑒𝑐𝑡𝑖𝑜𝑛 𝑆𝑢𝑟𝑓𝑎𝑐𝑒 𝐴𝑟𝑒𝑎,𝐴ൌ2𝜋𝑟ℎ ൅ 𝜋𝑟 ଶ 𝐷𝑖𝑠𝑐ℎ𝑎𝑟𝑔𝑒𝑑 𝑊𝑎𝑡𝑒𝑟 𝑉𝑜𝑙𝑢𝑚𝑒,𝑉ൌ𝜋𝑟ଶΔd 𝑃𝑒𝑟𝑐𝑜𝑙𝑎𝑡𝑖𝑜𝑛 𝑅𝑎𝑡𝑒 ൌ 𝑉𝐴⁄ ∆𝑇 𝐷𝑒𝑠𝑖𝑔𝑛 𝐼𝑛𝑓𝑖𝑙𝑡𝑟𝑎𝑡𝑖𝑜𝑛 𝑅𝑎𝑡𝑒 ൌ 𝑀𝑒𝑎𝑠𝑢𝑟𝑒𝑑 𝑃𝑒𝑟𝑐𝑜𝑙𝑎𝑡𝑖𝑜𝑛 𝑅𝑎𝑡𝑒 /𝑅𝐹 𝑇𝑜𝑡𝑎𝑙 𝑅𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛 𝐹𝑎𝑐𝑡𝑜𝑟,𝑅𝐹 ൌ 𝑅𝐹௧ ൈ𝑅𝐹௩ ൈ𝑅𝐹௦ FIGURE 7 APPENDIX A Geocon Project No. W1304-06-01 September 19, 2023 APPENDIX A FIELD INVESTIGATION The site was explored on February 8, 2021 by excavating four 8-inch diameter borings to depths ranging from approximately 30½ to 40½ feet below the existing ground surface using a truck-mounted, hollow-stem auger drilling machine. Representative and relatively undisturbed samples were obtained by driving a 3 inch, O. D., California Modified Sampler into the “undisturbed” soil mass with blows from a 140-pound auto-hammer falling 30 inches. The California Modified Sampler was equipped with 1-inch high by 23/8-inch diameter brass sampler rings to facilitate soil removal and testing. Bulk samples were also obtained. The soil conditions encountered in the borings were visually examined, classified and logged in general accordance with the Unified Soil Classification System (USCS). The logs of the borings are presented on Figures A1 through A4. The logs depict the soil and geologic conditions encountered and the depth at which samples were obtained. The logs also include our interpretation of the conditions between sampling intervals. Therefore, the logs contain both observed and interpreted data. We determined the lines designating the interface between soil materials on the logs using visual observations, penetration rates, excavation characteristics and other factors. The transition between materials may be abrupt or gradual. Where applicable, the logs were revised based on subsequent laboratory testing. The locations of the borings are shown on Figure 2A. AC: 5" BASE: NONE ARTIFICIAL FILL Silty Sand, medium dense, slightly moist, dark brown, fine- to medium-grained, trace coarse-grained. ALLUVIUM Sand, poorly graded, dense, slightly moist, light brown, fine- to medium-grained. - medium dense, trace coarse-grained, 3" rock fragment - increase in coarse-grained sand - very dense - dense, trace fine gravel - medium dense, brown - dense, some fine gravel 4.9 6.2 3.2 8.3 3.6 8.7 5.3 SP B1@5' B1@10' B1@15' B1@20' BULK 20-30' B1@22.5' B1@25' B1@27.5' 51 28 37 50 (6") 65 50 82 120.6 106.0 111.0 97.6 115.4 99.5 122.6 SAMPLE NO. HOLLOW STEM AUGER ... WATER TABLE OR SEEPAGE DEPTH IN FEET ... DRIVE SAMPLE (UNDISTURBED) GEOCON -- 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 DR Y D E N S I T Y EQUIPMENT BORING 1 RA MO I S T U R E BY: (P . C . F . ) DATE COMPLETED ... SAMPLING UNSUCCESSFUL ... DISTURBED OR BAG SAMPLE SOIL CLASS (USCS) GR O U N D W A T E R SAMPLE SYMBOLS CO N T E N T ( % ) ... CHUNK SAMPLE 02/08/2021ELEV. (MSL.) PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T * ) MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST W1304-06-01 BORING LOGS.GPJFigure A1, Log of Boring 1, Page 1 of 2 NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. W1304-06-01 - no fine gravel Sand, well-graded, dense, slightly moist, brown, fine- to coarse-grained. - increase in coarse-grained Total depth of boring: 40.5 feet Fill to 2 feet. No groundwater encountered. Backfilled with soil cuttings and tamped. Asphalt patched. *Penetration resistance for 140-pound hammer falling 30 inches by auto-hammer. 10.0 5.6 11.2 4.7 SP SW B1@30' B1@32.5' B1@35' B1@40' 63 59 62 60 101.5 113.1 101.4 114.8 SAMPLE NO. HOLLOW STEM AUGER ... WATER TABLE OR SEEPAGE DEPTH IN FEET ... DRIVE SAMPLE (UNDISTURBED) GEOCON -- 30 32 34 36 38 40 DR Y D E N S I T Y EQUIPMENT BORING 1 RA MO I S T U R E BY: (P . C . F . ) DATE COMPLETED ... SAMPLING UNSUCCESSFUL ... DISTURBED OR BAG SAMPLE SOIL CLASS (USCS) GR O U N D W A T E R SAMPLE SYMBOLS CO N T E N T ( % ) ... CHUNK SAMPLE 02/08/2021ELEV. (MSL.) PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T * ) MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST W1304-06-01 BORING LOGS.GPJFigure A1, Log of Boring 1, Page 2 of 2 NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. W1304-06-01 AC: 5" BASE: NONE ARTIFICIAL FILL Silty Sand, medium dense, slightly moist, dark brown, fine-grained, trace medium- to coarse-grained. ALLUVIUM Sand, poorly graded, medium dense, slightly moist, light brown, fine-grained, trace medium- to coarse-grained. - increase in medium- to coarse-grained, trace coarse gravel (to 3") - dense, fine- to coarse-grained - very dense, moist, light brown to brown - dense, trace silt - medium dense, increase in fine-grained, trace medium- to coarse-grained - dense, reddish brown 2.3 4.5 2.2 2.8 3.1 6.4 6.2 SP B2@5' B2@10' B2@15' B2@20' B2@22.5' B2@25' B2@27.5' 29 29 61 50 (5.5") 84 45 58 106.4 111.5 123.9 115.5 136.3 110.1 119.0 SAMPLE NO. HOLLOW STEM AUGER ... WATER TABLE OR SEEPAGE DEPTH IN FEET ... DRIVE SAMPLE (UNDISTURBED) GEOCON -- 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 DR Y D E N S I T Y EQUIPMENT BORING 2 RA MO I S T U R E BY: (P . C . F . ) DATE COMPLETED ... SAMPLING UNSUCCESSFUL ... DISTURBED OR BAG SAMPLE SOIL CLASS (USCS) GR O U N D W A T E R SAMPLE SYMBOLS CO N T E N T ( % ) ... CHUNK SAMPLE 02/08/2021ELEV. (MSL.) PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T * ) MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST W1304-06-01 BORING LOGS.GPJFigure A2, Log of Boring 2, Page 1 of 2 NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. W1304-06-01 - light brown, no silt Silty Sand, dense, moist, reddish brown, trace medium- to coarse-grained. Sand, well-graded, dense, moist, brown to light brown, fine-grained, trace medium- to coarse-grained. - very dense Total depth of boring: 40.5 feet Fill to 3 feet. No groundwater encountered. Backfilled with soil cuttings and tamped. Asphalt patched. *Penetration resistance for 140-pound hammer falling 30 inches by auto-hammer. 3.6 10.5 6.1 4.5 SP SM SW B2@30' B2@32.5' B2@35' B2@40' 52 51 62 50 (6") 116.8 113.6 105.1 88.3 SAMPLE NO. HOLLOW STEM AUGER ... WATER TABLE OR SEEPAGE DEPTH IN FEET ... DRIVE SAMPLE (UNDISTURBED) GEOCON -- 30 32 34 36 38 40 DR Y D E N S I T Y EQUIPMENT BORING 2 RA MO I S T U R E BY: (P . C . F . ) DATE COMPLETED ... SAMPLING UNSUCCESSFUL ... DISTURBED OR BAG SAMPLE SOIL CLASS (USCS) GR O U N D W A T E R SAMPLE SYMBOLS CO N T E N T ( % ) ... CHUNK SAMPLE 02/08/2021ELEV. (MSL.) PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T * ) MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST W1304-06-01 BORING LOGS.GPJFigure A2, Log of Boring 2, Page 2 of 2 NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. W1304-06-01 AC: 5" BASE: NONE ARTIFICIAL FILL Silty Sand, medium dense, slightly moist, dark brown, fine-grained, trace medium- to coarse-grained. ALLUVIUM Sand, medium dense, slightly moist, brown, fine- to medium-grained, trace coarse gravel. - increase in coarse-grained - some coarse-grained - trace fine gravel - decrease in fine gravel Silty Sand, medium dense, moist, dark brown, fine-grained. Sand, poorly graded, medium dense, slightly moist, light brown, fine- to medium-grained, trace coarse-grained. - reddish brown, fine-grained, trace medium- to coarse-grained - fine- to coarse-grained, trace fine gravel 4.9 3.7 6.4 4.9 3.1 14.0 SP SM SP B3@2.5' B3@5' BULK 5-10' B3@10' B3@12.5' B3@15' B3@17.5' B3@20' B3@25' 29 29 29 47 52 38 53 85.6 114.9 100.9 110.4 122.3 111.8 SAMPLE NO. HOLLOW STEM AUGER ... WATER TABLE OR SEEPAGE DEPTH IN FEET ... DRIVE SAMPLE (UNDISTURBED) GEOCON -- 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 DR Y D E N S I T Y EQUIPMENT BORING 3 RA MO I S T U R E BY: (P . C . F . ) DATE COMPLETED ... SAMPLING UNSUCCESSFUL ... DISTURBED OR BAG SAMPLE SOIL CLASS (USCS) GR O U N D W A T E R SAMPLE SYMBOLS CO N T E N T ( % ) ... CHUNK SAMPLE 02/08/2021ELEV. (MSL.) PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T * ) MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST W1304-06-01 BORING LOGS.GPJFigure A3, Log of Boring 3, Page 1 of 2 NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. W1304-06-01 - very dense Total depth of boring: 30.5 feet Fill to 4 feet. No groundwater encountered. Backfilled with soil cuttings and tamped. Asphalt patched. *Penetration resistance for 140-pound hammer falling 30 inches by auto-hammer. SPB3@30'50 (6") SAMPLE NO. HOLLOW STEM AUGER ... WATER TABLE OR SEEPAGE DEPTH IN FEET ... DRIVE SAMPLE (UNDISTURBED) GEOCON -- 30 DR Y D E N S I T Y EQUIPMENT BORING 3 RA MO I S T U R E BY: (P . C . F . ) DATE COMPLETED ... SAMPLING UNSUCCESSFUL ... DISTURBED OR BAG SAMPLE SOIL CLASS (USCS) GR O U N D W A T E R SAMPLE SYMBOLS CO N T E N T ( % ) ... CHUNK SAMPLE 02/08/2021ELEV. (MSL.) PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T * ) MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST W1304-06-01 BORING LOGS.GPJFigure A3, Log of Boring 3, Page 2 of 2 NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. W1304-06-01 AC: 5" BASE: NONE ARTIFICIAL FILL Silty Sand, medium dense, moist, dark brown, fine-grained, trace medium-grained. ALLUVIUM Sand, poorly graded, medium dense, dry to slightly moist, light brown, fine- to medium-grained. - dry, fine- to coarse-grained - brown, trace fine gravel (to 3") - very dense, reddish brown, decrease in coarse-grained - medium dense, fine-grained, trace silt Sand, well-graded, dense, slightly moist, light brown, fine- to coarse-grained, trace fine to coarse gravel (to 3"). 2.6 4.6 3.7 3.1 7.4 4.9 4.5 2.9 SP SW B4@5' B4@10' B4@12.5' B4@15' B4@17.5' B4@20' B4@22.5' B4@25' 22 31 29 41 50 (5.5") 34 49 97 116.7 102.5 115.8 110.3 81.1 111.1 114.2 121.4 SAMPLE NO. HOLLOW STEM AUGER ... WATER TABLE OR SEEPAGE DEPTH IN FEET ... DRIVE SAMPLE (UNDISTURBED) GEOCON -- 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 DR Y D E N S I T Y EQUIPMENT BORING 4 RA MO I S T U R E BY: (P . C . F . ) DATE COMPLETED ... SAMPLING UNSUCCESSFUL ... DISTURBED OR BAG SAMPLE SOIL CLASS (USCS) GR O U N D W A T E R SAMPLE SYMBOLS CO N T E N T ( % ) ... CHUNK SAMPLE 02/08/2021ELEV. (MSL.) PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T * ) MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST W1304-06-01 BORING LOGS.GPJFigure A4, Log of Boring 4, Page 1 of 2 NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. W1304-06-01 Total depth of boring: 30.5 feet Fill to 2.5 feet. No groundwater encountered. Percolation testing performed. Backfilled with soil cuttings and tamped. Asphalt patched. *Penetration resistance for 140-pound hammer falling 30 inches by auto-hammer. 2.8SWB4@30'50 (6") 123.8 SAMPLE NO. HOLLOW STEM AUGER ... WATER TABLE OR SEEPAGE DEPTH IN FEET ... DRIVE SAMPLE (UNDISTURBED) GEOCON -- 30 DR Y D E N S I T Y EQUIPMENT BORING 4 RA MO I S T U R E BY: (P . C . F . ) DATE COMPLETED ... SAMPLING UNSUCCESSFUL ... DISTURBED OR BAG SAMPLE SOIL CLASS (USCS) GR O U N D W A T E R SAMPLE SYMBOLS CO N T E N T ( % ) ... CHUNK SAMPLE 02/08/2021ELEV. (MSL.) PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T * ) MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST W1304-06-01 BORING LOGS.GPJFigure A4, Log of Boring 4, Page 2 of 2 NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. W1304-06-01 APPENDIX B Geocon Project No. W1304-06-01 September 19, 2023 APPENDIX B LABORATORY TESTING Laboratory tests were performed in accordance with generally accepted test methods of the “American Society for Testing and Materials (ASTM)”, or other suggested procedures. Selected samples were tested for direct shear strength, consolidation, corrosivity, and in-place dry density and moisture content. The results of the laboratory tests are summarized in Figures B1 through B20. The in-place dry density and moisture content of the samples tested are presented on the boring logs, Appendix A. Project No.: W1304-06-01 14.6 DIRECT SHEAR TEST RESULTS 34 East Santa Clara Street Arcadia, CaliforniaConsolidated Drained ASTM D-3080 Checked by: PZ 14.5 Sept 2023 Figure B1 Ultimate 100 38.1 Final Moisture Content (%)18.9 31.6 30.2 Peak 300 39.5 Soil Height Before Shearing (in.) 1.2 1.2 1.2 C (psf)Initial Degree of Saturation (%) 22.5 Strength Parameters Initial Dry Density (pcf)97.2 110.5 109.9 Light Brown Sand (SP)Ring Inside Diameter (in.)2.375 2.375 2.375 Initial Moisture Content (%)6.1 6.2 6.0 Soil Identification:Initial Sample Height (in.)1.0 1.0 1.0 0.05 Depth (ft)10 Shear Stress @ End of Test (ksf) 0.86 3.32 4.00 Sample Type:Ring Deformation Rate (in./min.)0.05 0.05 4.42 Boring No. B1 Normal Strest (kip/ft2)1 3 5 Sample No. B1@10'Peak Shear Stress (kip/ft²)1.12 3.44 0.0 1.0 2.0 3.0 4.0 5.0 0.0 1.0 2.0 3.0 4.0 5.0 Sh e a r S t r e s s ( k s f ) Normal Stress (ksf) Project No.: W1304-06-01 4.51 Boring No. B4 Normal Strest (kip/ft2) 1 3 5 Sample No. B4@10'Peak Shear Stress (kip/ft²) 1.22 3.94 0.05 Depth (ft) 10 Shear Stress @ End of Test (ksf) 0.72 2.87 4.07 Sample Type:Ring Deformation Rate (in./min.)0.05 0.05 Soil Identification:Initial Sample Height (in.)1.0 1.0 1.0 Light Brown Sand (SP)Ring Inside Diameter (in.)2.375 2.375 2.375 Initial Moisture Content (%)5.9 4.6 5.9 Strength Parameters Initial Dry Density (pcf)98.4 104.1 101.5 20.1 24.0 Peak 400 39.4 Soil Height Before Shearing (in.) 1.2 1.2 1.2 C (psf)Initial Degree of Saturation (%) 22.2 Ultimate 0 39.4 Final Moisture Content (%)18.9 16.3 DIRECT SHEAR TEST RESULTS 34 East Santa Clara Street Arcadia, CaliforniaConsolidated Drained ASTM D-3080 Checked by: PZ 16.3 Sept 2023 Figure B2 0.0 1.0 2.0 3.0 4.0 5.0 0.0 1.0 2.0 3.0 4.0 5.0 Sh e a r S t r e s s ( k s f ) Normal Stress (ksf) Project No.: W1304-06-01 4.25 Boring No. B3 Normal Strest (kip/ft2) 1 3 5 Sample No. B3@12.5'Peak Shear Stress (kip/ft²) 1.11 2.63 0.05 Depth (ft) 12.5 Shear Stress @ End of Test (ksf) 0.81 2.22 3.85 Sample Type:Ring Deformation Rate (in./min.)0.05 0.05 Soil Identification:Initial Sample Height (in.)1.0 1.0 1.0 Brown Sand (SP)Ring Inside Diameter (in.)2.375 2.375 2.375 Initial Moisture Content (%)5.8 6.4 6.4 Strength Parameters Initial Dry Density (pcf)99.7 98.8 100.4 24.5 25.4 Peak 305 38.1 Soil Height Before Shearing (in.) 1.2 1.2 1.2 C (psf)Initial Degree of Saturation (%) 22.8 Ultimate 11 37.3 Final Moisture Content (%)18.5 18.1 DIRECT SHEAR TEST RESULTS 34 East Santa Clara Street Arcadia, CaliforniaConsolidated Drained ASTM D-3080 Checked by: PZ 18.1 Sept 2023 Figure B3 0.0 1.0 2.0 3.0 4.0 5.0 0.0 1.0 2.0 3.0 4.0 5.0 Sh e a r S t r e s s ( k s f ) Normal Stress (ksf) Project No.: W1304-06-01 4.69 Boring No. B1 Normal Strest (kip/ft2) 1 3 5 Sample No. B1@20'Peak Shear Stress (kip/ft²) 1.17 3.03 0.05 Depth (ft) 20 Shear Stress @ End of Test (ksf) 1.01 2.63 4.05 Sample Type:Ring Deformation Rate (in./min.)0.05 0.05 Soil Identification:Initial Sample Height (in.)1.0 1.0 1.0 Light Brown Sand (SP)Ring Inside Diameter (in.)2.375 2.375 2.375 Initial Moisture Content (%)6.2 6.4 8.3 Strength Parameters Initial Dry Density (pcf)96.8 95.0 100.3 22.4 32.8 Peak 318 41.4 Soil Height Before Shearing (in.) 1.2 1.2 1.2 C (psf)Initial Degree of Saturation (%) 22.5 Ultimate 280 37.3 Final Moisture Content (%)22.6 17.1 DIRECT SHEAR TEST RESULTS 34 East Santa Clara Street Arcadia, CaliforniaConsolidated Drained ASTM D-3080 Checked by: PZ 20.7 Sept 2023 Figure B4 0.0 1.0 2.0 3.0 4.0 5.0 0.0 1.0 2.0 3.0 4.0 5.0 Sh e a r S t r e s s ( k s f ) Normal Stress (ksf) Project No.: W1304-06-01 5.03 Boring No. B1 Normal Strest (kip/ft2) 1 3 5 Sample No. B1@25'Peak Shear Stress (kip/ft²) 1.43 3.07 0.05 Depth (ft) 25 Shear Stress @ End of Test (ksf) 1.09 2.79 4.93 Sample Type:Ring Deformation Rate (in./min.)0.05 0.05 Soil Identification:Initial Sample Height (in.)1.0 1.0 1.0 Brown Sand (SP)Ring Inside Diameter (in.)2.375 2.375 2.375 Initial Moisture Content (%)8.7 0.0 11.1 Strength Parameters Initial Dry Density (pcf)98.1 105.3 96.7 0.1 40.1 Peak 474 42.0 Soil Height Before Shearing (in.) 1.2 1.2 1.2 C (psf)Initial Degree of Saturation (%) 32.8 Ultimate 61 43.8 Final Moisture Content (%)17.8 16.2 DIRECT SHEAR TEST RESULTS 34 East Santa Clara Street Arcadia, CaliforniaConsolidated Drained ASTM D-3080 Checked by: PZ 15.5 Sept 2023 Figure B5 0.0 1.0 2.0 3.0 4.0 5.0 0.0 1.0 2.0 3.0 4.0 5.0 Sh e a r S t r e s s ( k s f ) Normal Stress (ksf) Project No.: W1304-06-01 4.20 Boring No. B1 Normal Strest (kip/ft2) 1 3 5 Sample No. B1@30'Peak Shear Stress (kip/ft²) 1.37 3.01 0.05 Depth (ft) 30 Shear Stress @ End of Test (ksf) 0.91 2.88 3.60 Sample Type:Ring Deformation Rate (in./min.)0.05 0.05 Soil Identification:Initial Sample Height (in.)1.0 1.0 1.0 Brown Sand (SP)Ring Inside Diameter (in.)2.375 2.375 2.375 Initial Moisture Content (%)9.1 10.0 15.6 Strength Parameters Initial Dry Density (pcf)98.7 104.2 92.1 43.5 50.8 Peak 650 35.3 Soil Height Before Shearing (in.) 1.2 1.2 1.2 C (psf)Initial Degree of Saturation (%) 34.8 Ultimate 250 34.0 Final Moisture Content (%)19.8 18.5 DIRECT SHEAR TEST RESULTS 34 East Santa Clara Street Arcadia, CaliforniaConsolidated Drained ASTM D-3080 Checked by: PZ 17.2 Sept 2023 Figure B6 0.0 1.0 2.0 3.0 4.0 5.0 0.0 1.0 2.0 3.0 4.0 5.0 Sh e a r S t r e s s ( k s f ) Normal Stress (ksf) Project No.: W1304-06-01 4.35 Boring No. B1 Normal Strest (kip/ft2) 1 3 5 Sample No. B1@35'Peak Shear Stress (kip/ft²) 1.09 2.72 0.05 Depth (ft) 35 Shear Stress @ End of Test (ksf) 0.81 2.47 3.76 Sample Type:Ring Deformation Rate (in./min.)0.05 0.05 Soil Identification:Initial Sample Height (in.)1.0 1.0 1.0 Brown Sand (SW)Ring Inside Diameter (in.)2.375 2.375 2.375 Initial Moisture Content (%)8.0 7.6 11.2 Strength Parameters Initial Dry Density (pcf)99.9 101.6 102.5 31.3 46.8 Peak 280 39.1 Soil Height Before Shearing (in.) 1.2 1.2 1.2 C (psf)Initial Degree of Saturation (%) 31.2 Ultimate 130 36.5 Final Moisture Content (%)19.5 18.6 DIRECT SHEAR TEST RESULTS 34 East Santa Clara Street Arcadia, CaliforniaConsolidated Drained ASTM D-3080 Checked by: PZ 17.5 Sept 2023 Figure B7 0.0 1.0 2.0 3.0 4.0 5.0 0.0 1.0 2.0 3.0 4.0 5.0 Sh e a r S t r e s s ( k s f ) Normal Stress (ksf) Project No.: W1304-06-01 WATER ADDED AT 2.0 KSF SAMPLE ID. B3@10 SOIL TYPE DRY DENSITY (PCF) INITIAL MOISTURE (%) FINAL MOISTURE (%) Brown Sand (SP) 103.4 3.7 17.8 CONSOLIDATION TEST RESULTS 34 East Santa Clara Street Arcadia, California Checked by: PZ ASTM D-2435 Sept 2023 Figure B8 0 1 2 3 4 5 6 7 8 9 10 0.1 1.0 10.0 Pe r c e n t C o n s o l i d a t i o n Consolidation Pressure (ksf) Project No.: W1304-06-01 CONSOLIDATION TEST RESULTS 34 East Santa Clara Street Arcadia, California Checked by: PZ ASTM D-2435 Sept 2023 Figure B9 WATER ADDED AT 2.0 KSF SAMPLE ID. B4@12.5 SOIL TYPE DRY DENSITY (PCF) INITIAL MOISTURE (%) FINAL MOISTURE (%) Brown Sand (SP) 105.4 3.7 17.1 0 1 2 3 4 5 6 7 8 9 10 0.1 1.0 10.0 Pe r c e n t C o n s o l i d a t i o n Consolidation Pressure (ksf) Project No.: W1304-06-01 WATER ADDED AT 2.0 KSF SAMPLE ID. B3@15 SOIL TYPE DRY DENSITY (PCF) INITIAL MOISTURE (%) FINAL MOISTURE (%) Brown Sand (SP) 110.9 4.9 14.0 CONSOLIDATION TEST RESULTS 34 East Santa Clara Street Arcadia, California Checked by: PZ ASTM D-2435 Sept 2023 Figure B10 0 1 2 3 4 5 6 7 8 9 10 0.1 1.0 10.0 Pe r c e n t C o n s o l i d a t i o n Consolidation Pressure (ksf) Project No.: W1304-06-01 CONSOLIDATION TEST RESULTS 34 East Santa Clara Street Arcadia, California Checked by: PZ ASTM D-2435 Sept 2023 Figure B11 WATER ADDED AT 2.0 KSF SAMPLE ID. B4@17.5 SOIL TYPE DRY DENSITY (PCF) INITIAL MOISTURE (%) FINAL MOISTURE (%) Brown Sand (SP) 83.5 7.4 26.5 0 1 2 3 4 5 6 7 8 9 10 0.1 1.0 10.0 Pe r c e n t C o n s o l i d a t i o n Consolidation Pressure (ksf) Project No.: W1304-06-01 WATER ADDED AT 2.0 KSF SAMPLE ID. B3@20 SOIL TYPE DRY DENSITY (PCF) INITIAL MOISTURE (%) FINAL MOISTURE (%) Dark Brown Silty Sand (SM)118.1 14.0 15.0 CONSOLIDATION TEST RESULTS 34 East Santa Clara Street Arcadia, California Checked by: PZ ASTM D-2435 Sept 2023 Figure B12 0 1 2 3 4 5 6 7 8 9 10 0.1 1.0 10.0 Pe r c e n t C o n s o l i d a t i o n Consolidation Pressure (ksf) Project No.: W1304-06-01 WATER ADDED AT 2.0 KSF SAMPLE ID. B4@22.5 SOIL TYPE DRY DENSITY (PCF) INITIAL MOISTURE (%) FINAL MOISTURE (%) Reddish Brown Sand (SP)107.9 4.5 18.5 CONSOLIDATION TEST RESULTS 34 East Santa Clara Street Arcadia, California Checked by: PZ ASTM D-2435 Sept 2023 Figure B13 0 1 2 3 4 5 6 7 8 9 10 0.1 1.0 10.0 Pe r c e n t C o n s o l i d a t i o n Consolidation Pressure (ksf) Project No.: W1304-06-01 WATER ADDED AT 2.0 KSF SAMPLE ID. B2@25 SOIL TYPE DRY DENSITY (PCF) INITIAL MOISTURE (%) FINAL MOISTURE (%) Brown Sand (SP) 96.7 6.4 22.0 CONSOLIDATION TEST RESULTS 34 East Santa Clara Street Arcadia, California Checked by: PZ ASTM D-2435 Sept 2023 Figure B14 0 1 2 3 4 5 6 7 8 9 10 0.1 1.0 10.0 Pe r c e n t C o n s o l i d a t i o n Consolidation Pressure (ksf) Project No.: W1304-06-01 WATER ADDED AT 2.0 KSF SAMPLE ID. B1@27.5 SOIL TYPE DRY DENSITY (PCF) INITIAL MOISTURE (%) FINAL MOISTURE (%) BrownSand (SP) 117.7 5.3 12.7 CONSOLIDATION TEST RESULTS 34 East Santa Clara Street Arcadia, California Checked by: PZ ASTM D-2435 Sept 2023 Figure B15 0 1 2 3 4 5 6 7 8 9 10 0.1 1.0 10.0 Pe r c e n t C o n s o l i d a t i o n Consolidation Pressure (ksf) Project No.: W1304-06-01 WATER ADDED AT 2.0 KSF SAMPLE ID. B2@30 SOIL TYPE DRY DENSITY (PCF) INITIAL MOISTURE (%) FINAL MOISTURE (%) Light Brown Sand (SP)103.1 3.6 18.7 CONSOLIDATION TEST RESULTS 34 East Santa Clara Street Arcadia, California Checked by: PZ ASTM D-2435 Sept 2023 Figure B16 0 1 2 3 4 5 6 7 8 9 10 0.1 1.0 10.0 Pe r c e n t C o n s o l i d a t i o n Consolidation Pressure (ksf) Project No.: W1304-06-01 WATER ADDED AT 2.0 KSF SAMPLE ID. B1@32.5 SOIL TYPE DRY DENSITY (PCF) INITIAL MOISTURE (%) FINAL MOISTURE (%) Brown Sand (SP) 102.3 5.6 18.1 CONSOLIDATION TEST RESULTS 34 East Santa Clara Street Arcadia, California Checked by: PZ ASTM D-2435 Sept 2023 Figure B17 0 1 2 3 4 5 6 7 8 9 10 0.1 1.0 10.0 Pe r c e n t C o n s o l i d a t i o n Consolidation Pressure (ksf) Project No.: W1304-06-01 CONSOLIDATION TEST RESULTS 34 East Santa Clara Street Arcadia, California Checked by: PZ ASTM D-2435 Sept 2023 Figure B18 WATER ADDED AT 2.0 KSF SAMPLE ID. B2@35 SOIL TYPE DRY DENSITY (PCF) INITIAL MOISTURE (%) FINAL MOISTURE (%) Brown Sand (SW) 101.9 4.4 17.7 0 1 2 3 4 5 6 7 8 9 10 0.1 1.0 10.0 Pe r c e n t C o n s o l i d a t i o n Consolidation Pressure (ksf) Project No.: W1304-06-01 WATER ADDED AT 2.0 KSF SAMPLE ID. B1@40 SOIL TYPE DRY DENSITY (PCF) INITIAL MOISTURE (%) FINAL MOISTURE (%) Brown Sand (SW) 112.3 4.7 15.3 CONSOLIDATION TEST RESULTS 34 East Santa Clara Street Arcadia, California Checked by: PZ ASTM D-2435 Sept 2023 Figure B19 0 1 2 3 4 5 6 7 8 9 10 0.1 1.0 10.0 Pe r c e n t C o n s o l i d a t i o n Consolidation Pressure (ksf) Project No.: W1304-06-01 Sample No. SUMMARY OF LABORATORY WATER SOLUBLE SULFATE TEST RESULTS CALIFORNIA TEST NO. 417 Sample No.Water Soluble Sulfate (% SQ4)Sulfate Exposure* Chloride Ion Content (%) 0.002 0.004 SUMMARY OF LABORATORY CHLORIDE CONTENT TEST RESULTS EPA NO. 325.3 B3@5-10' B1@20-25' B3@5-10 0.000 S0 B1@20-25'0.000 S0 SUMMARY OF LABORATORY POTENTIAL OF HYDROGEN (pH) AND RESISTIVITY TEST RESULTS CALIFORNIA TEST NO. 643 Sample No. B3@5-10' B1@20-25' pH 8.4 7.9 Resistivity (ohm centimeters) 21000 (Mildly Corrosive) 26000 (Mildly Corrosive) Checked by: PZ CORROSIVITY TEST RESULTS 34 East Santa Clara Street Arcadia, California Sept 2023 Figure B20