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HomeMy WebLinkAboutAppendix E - Preliminary Geotechnical Report Appendix E Preliminary Geotechnical Report PRELIMINARY GEOTECHNICAL INVESTIGATION AND FEASIBILITY LEVEL INFILTRATION TESTING PROPOSED MULTI-FAMILY RESIDENTIAL DEVELOPMENT 15926 FOOTHILL BOULEVARD (APNs 1110-361-15, -16, -22, AND -23) CITY OF FONTANA, SAN BERNARDINO COUNTY, CALIFORNIA 91768 FOR BEGONIA REAL ESTATE DEVELOPMENT, INC. 17800 CASTLETON STREET, SUITE 566 CITY OF INDUSTRY, CALIFORNIA W.O. 8027-A-SC JANUARY 21, 2021 Geotechnical C Geologic C Coastal C Environmental 18451 Collier Avenue, Suite A C Lake Elsinore, California 92530 C (951) 471-0700 C FAX (951) 471-0702 C www.geosoilsinc.com January 21, 2021 W.O. 8027-A-SC Begonia Real Estate Development, Inc. 17800 Castleton Street, Suite 566 City of Industry, California 91748 Attention:Mr. Rod Fermin Subject:Preliminary Geotechnical Investigation and Feasibility Level Infiltration Testing, Proposed Multi-Family Residential Development, 15926 Foothill Boulevard (APN’s 1110-361-15, -16, -22, and -23), City of Fontana, San Bernardino County, California Dear Mr. Fermin: In accordance with your request and authorization, GeoSoils, Inc. (GSI) is presenting the results of our preliminary geotechnical investigation and infiltration feasibility testing for the Foothill & Tokay project, located at 15926 Foothill Boulevard in the City of Fontana, San Bernardino County, California. The purpose of this study was to evaluate the onsite soils and geologic conditions and their effects on the proposed 2- to 4- story multi-family residential condominium development and associated 5-level parking structure from a geotechnical viewpoint, and to provide appropriate conclusions and recommendations for development of the property. EXECUTIVE SUMMARY Based on our literature research and review of available geologic data for the area, our field exploration, laboratory testing, and geologic and geotechnical engineering analyses, the proposed development of the project site appears suitable for its intended multi-family residential use from a geotechnical viewpoint, provided the conclusions and recommendations presented in the text of this report are properly implemented during design, construction, and development of the proposed project. The primary developmental considerations are summarized below: •Based on conversations with the client and a review of the conceptual site plan prepared by Humphreys & Partners Architects, L.P. (HPA, 2020), it is our understanding that proposed development will consist of preparing the project site for a 423-unit, 2- to 4-story multi-family condominium complex, with an at grade, 5 level parking structure, swimming pool, courtyard, leasing lobby, fitness facilities, exterior landscaping, pavements, and flatwork improvements. Significant plan cuts and fills are not anticipated for this relatively flat-lying site. GeoSoils, Inc.Begonia Real Estate Development, Inc.W.O. 8027-A-SC File: e\wp10\murr\sc8000\8027a.pgi Page Two •Remedial grading will generally consist of the removal of all surficial deposits of colluvium and undocumented fill, and near-surface young alluvial fan deposits prior to fill placement, in areas proposed for settlement-sensitive improvements. Approximate depths of removals are outlined in the conclusions and recommendations section of this report. For preliminary planning purposes, removals are estimated to be on the order of ±4 to ±5 feet across a majority of the site, with localized deeper removals on the order of ±10 feet, or deeper, within the influence of the proposed parking garage structure. Actual removal depths will be evaluated in the field during site grading. •A minimum fill blanket thickness of at least 4 feet, or 2 feet below the bottom of the deepest footing is recommended for foundation support of the 2- to 4-story residential structures. For the parking garage structure, a minimum fill thickness of 5 feet is recommended beneath the bottom of the deepest parking garage foundations. As such, deeper foundation systems may require overexcavation and/or undercutting of the underlying soils, beyond the vertical limits of the typical removal depth. •Based on the the presence of existing offsite improvements about portions of the perimeter of the site and the anticipated depths of remedial site grading (i.e., ±4 to ±5 feet overexcavation), appropriate shoring and/or slot-cutting during site grading may be necessary to protect the adjoining improvements. In addition, and existing power line, with wooden poles, transects the southern portion of the property. Based on our review of the conceptual site plan prepared by HPA (2020), it appears the power line will be removed and relocated during site construction. Consideration should be given to having the power line relocated prior to site grading, as not to interfere with proposed remedial site grading. Native site soils are relatively cohesionless and caving should be anticipated during trenching. Underground construction should consider “Type B” soil conditions per CalOSHA trenching guidelines. •All vegetation and trees, existing improvements (if any), and other deleterious materials should be removed from the site and properly disposed of offsite. Unsuitable near surface soils should be removed to expose competent unweathered young alluvial fan deposits, prior to fill placement. The excavated soils may be reused as engineered fill provided that major concentrations of debris and rubble have been removed prior to fill placement. •Based on our review and analysis, the project site is not located within in an area designated in the San Bernardino County general plan (SBC, 2010) as having potential for liquefaction during a seismic event. Furthermore, our review of Jennings and Bryant (2010) indicates that there are no known active faults crossing this site, and the site is not within an Alquist-Priolo Earthquake Fault Zone (Bryant and Hart, 2007). GeoSoils, Inc.Begonia Real Estate Development, Inc.W.O. 8027-A-SC File: e\wp10\murr\sc8000\8027a.pgi Page Three •Owing to the gravelly and cobbly nature of site soils encountered during our subsurface investigation, there is a potential that oversized rock materials (i.e., greater than 12 inches) will be encountered during site grading. Based upon the proposed development plan and our field exploration, the earth materials onsite should be readily rippable with conventional earthwork equipment in good working order. •Expansion index (E.I.) testing (E.I. = <5) indicates that onsite soils are generally very low in expansion potential. Therefore, preliminary foundation recommendations for very low expansive soils are provided herein. •Onsite soils have been evaluated for soluble sulfate/corrosion potential. For preliminary planning purposes, and in accordance with the latest edition of the 2019 CBC (CBSC, 2019a), the soluble sulfate content is classified as “S0” (<0.10 water-soluble sulfate in soil, percentage by mass, is considered Class S0 [ACI, 2014a]), and sulfate-resistant concrete is not currently anticipated. Based on the results of the saturated resistivity and pH testing, the onsite soils are generally considered neutral (a pH of 6.6 to 7.3 is considered neutral) and are mildly corrosive to ferrous metals in a saturated state (over 10,000 ohm-cm is considered mildly corrosive). Chlorides are non-detect. The anticipated corrosive soil conditions should be confirmed with testing upon the completion of remedial grading/grading onsite. •Based upon the assumed current design configuration, site geology, the results of our settlement analysis, and the anticipated ground modification, a total settlement (static, dynamic, and hydrocollapse) is anticipated to be on the order of at least 2½ inches, with a differential settlement on the order of 1½ inches over a 50-foot span for the planned residential construction. This minimum level of deformation should be considered in foundation design and planning, on a preliminary basis. Supplemental analysis will be recommended once preliminary loads for the parking structure are provided. •Infiltration feasibility testing conducted during this study indicates a design rate of about ±12.96 inches per hour, with a safety factor of 2.0 (minimum).. •In general and based upon the available data to date, regional groundwater is not expected to be a factor in the development of the site. However, due to the nature of the site materials, seepage may be encountered due to irrigation, along with seasonal perched water resulting from excess rainfall. Minimizing irrigation will lessen this potential. Although not anticipated, should areas of seepage develop during or after site grading, recommendations for minimizing this effect could be provided upon request. GeoSoils, Inc.Begonia Real Estate Development, Inc.W.O. 8027-A-SC File: e\wp10\murr\sc8000\8027a.pgi Page Four •Adverse geologic features that would preclude project feasibility (e.g., shallow groundwater, liquefiable soils, etc.) were not encountered. •The recommendations presented in this report should be incorporated into the planning, design, and construction considerations of the project. GeoSoils, Inc.Begonia Real Estate Development, Inc.W.O. 8027-A-SC File: e\wp10\murr\sc8000\8027a.pgi Page Five The opportunity to be of service is sincerely appreciated. If you should have any questions, please do not hesitate to contact our office. Respectfully submitted, GeoSoils, Inc. Todd A. Greer David W. Skelly Engineering Geologist, CEG 2377 Civil Engineer, RCE 47857 RGC/TAG/JPF/DWS/mn Distribution:(1) Addressee (email pdf) GeoSoils, Inc. TABLE OF CONTENTS SCOPE OF SERVICES ...................................................1 SITE DESCRIPTION .....................................................1 PROPOSED DEVELOPMENT ..............................................3 FIELD STUDIES .........................................................3 REGIONAL AND SITE GEOLOGY...........................................3 Regional Geologic Setting ...........................................3 Local Geology ....................................................4 Site Geologic Units.................................................4 Undocumented Fill (Map Symbol - afu)...........................4 Quaternary-Age Colluvium (Not Mapped).........................4 Holocene/Late Pleistocene-age Young Alluvial Fan Deposits (Map Symbol - Qyfl)..........................................5 GROUNDWATER ........................................................5 FAULTING AND REGIONAL SEISMICITY.....................................6 Local and Regional Faults ...........................................6 Historical Site Acceleration ..........................................7 Seismic Shaking Parameters .........................................7 LIQUEFACTION POTENTIAL ..............................................9 Liquefaction ......................................................9 Seismic Densification ..............................................10 Summary........................................................10 Other Geologic/Secondary Seismic Hazards ...........................10 LABORATORY TESTING .................................................11 Classification.....................................................11 Laboratory Standard...............................................11 Expansion Potential ...............................................11 Direct Shear Test .................................................11 Particle-Size Analysis ..............................................12 Resistance Value .................................................12 Saturated Resistivity, pH, and Soluble Sulfates, and Chlorides .............12 Corrosion Summary .........................................12 PRELIMINARY SETTLEMENT ANALYSIS ....................................13 PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS ....................14 General .........................................................14 Demolition/Grubbing ..............................................14 GeoSoils, Inc.Begonia Real Estate Development, Inc.Table of Contents File: e:\wp10\murr\sc8000\8027a.pgi Page ii Treatment of Existing Ground .......................................15 Fill Placement ....................................................16 Preliminary Earthwork Factors.......................................16 PRELIMINARY RECOMMENDATIONS - FOUNDATIONS .......................17 General .........................................................17 Preliminary Conventional Foundation Design ...........................18 General ...................................................18 PRELIMINARY FOUNDATION CONSTRUCTION RECOMMENDATIONS ...........20 Post-Tensioned Foundations........................................21 Slab Subgrade Pre-Soaking ...................................22 Perimeter Cut-Off Walls.......................................23 Post-Tensioned Foundation Design .............................23 Soil Support Parameters ......................................23 Mat Foundations..................................................24 Mat Foundation Design.......................................25 Confirmation Testing for Final Foundation Design .......................26 SOIL MOISTURE TRANSMISSION CONSIDERATIONS ........................26 INFILTRATION FEASIBILITY TESTING ......................................28 Percolation Test Procedures ........................................28 ONSITE INFILTRATION-RUNOFF RETENTION SYSTEMS ......................29 PRELIMINARY WALL DESIGN PARAMETERS ................................32 General .........................................................32 Conventional Retaining Walls .......................................33 Retaining Wall Foundation Design ..............................33 Restrained Walls ............................................34 Cantilevered Walls...........................................34 Seismic Surcharge ................................................35 Retaining Wall Backfill and Drainage..................................36 Wall/Retaining Wall Footing Transitions ...............................36 Slope Setback Considerations for Footings ............................40 DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS .......................40 PRELIMINARY PORTLAND CEMENT CONCRETE PAVEMENT DESIGN RECOMMENDATIONS ...........................42 Asphaltic Concrete Pavement (ACP)..................................42 Portland Concrete Cement Pavement (PCCP)..........................43 PCC Pavement Joints..............................................43 Weakened Plane Joints.......................................43 GeoSoils, Inc.Begonia Real Estate Development, Inc.Table of Contents File: e:\wp10\murr\sc8000\8027a.pgi Page iii Expansion Joints ............................................43 Contact Joints ..............................................43 Slab Reinforcement ...............................................44 Concrete Pavers ..................................................44 PAVEMENT GRADING RECOMMENDATIONS ...............................44 General .........................................................44 Subgrade .......................................................44 Aggregate Base ..................................................45 Drainage ........................................................45 Additional Considerations ..........................................45 DEVELOPMENT CRITERIA ...............................................45 Slope Maintenance and Planting.....................................45 Drainage ........................................................46 Erosion Control...................................................46 Landscape Maintenance ...........................................46 Gutters and Downspouts ...........................................47 Subsurface and Surface Water ......................................47 Site Improvements ................................................47 Tile Flooring .....................................................48 Additional Grading ................................................48 Footing Trench Excavation .........................................48 Trenching/Temporary Construction Backcuts ..........................48 Utility Trench Backfill ..............................................49 SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING .......................49 OTHER DESIGN PROFESSIONALS/CONSULTANTS ..........................50 PLAN REVIEW .........................................................51 LIMITATIONS ..........................................................51 FIGURES: Figure 1 - Site Location Map .........................................2 Detail 1 - Typical Retaining Wall Backfill and Drainage Detail ..............38 Detail 2 - Retaining Wall Backfill and Subdrain Detail Geotextile Drain .......39 Detail 3 - Retaining Wall and Subdrain Detail Clean Sand Backfill ...........40 ATTACHMENTS: Appendix A - References ...................................Rear of Text Appendix B - Test Pit Logs..................................Rear of Text Appendix C - Seismicity Data................................Rear of Text GeoSoils, Inc.Begonia Real Estate Development, Inc.Table of Contents File: e:\wp10\murr\sc8000\8027a.pgi Page iv Appendix D - Laboratory Test Results .........................Rear of Text Appendix E - Field Infiltration Test Data/ Factor of Safety Work Sheet ...........................Rear of Text Appendix F -General Earthwork, Grading Guidelines, and Preliminary Criteria ..................................Rear of Text Plate 1 - Geotechnical Map .................................Rear of Text GeoSoils, Inc. PRELIMINARY GEOTECHNICAL INVESTIGATION AND FEASIBILITY LEVEL INFILTRATION TESTING PROPOSED MULTI-FAMILY RESIDENTIAL DEVELOPMENT 15926 FOOTHILL BOULEVARD (APN’s 1110-361-15, -16, -22, AND -23) CITY OF FONTANA, SAN BERNARDINO COUNTY, CALIFORNIA 91768 SCOPE OF SERVICES The scope of our services has included the following: 1.Review of available soils and geologic data for the project site and vicinity, including aerial photos (USDA, 1980) of the subject area (see Appendix A). 2.Geologic site reconnaissance and geologic mapping of surficial deposits. 3.Subsurface exploration consisting of the advancement of ten (1) exploratory test pits with a rubber tire backhoe for geotechnical logging, and soil sampling (Appendix B). Two (2) of the test pits advanced onsite were subsequently utilized for infiltration feasibility testing. 4.General areal seismicity evaluation (Appendix C). 5.Pertinent laboratory testing of representative soil samples collected during our subsurface exploration program. Testing included in-situ moisture and density, maximum density, expansion index, direct shear, and soil classification of the materials encountered during our field study. Results of our laboratory testing are provided in Appendix D. 6.Calculation of converted infiltration rates to be utilized by the design civil engineer. The field infiltration test data is provided in Appendix E. 7.Appropriate engineering and geologic analyses of data collected and preparation of this report and accompaniments. SITE DESCRIPTION The ±10-acre site (APN’s 1110-361-15, -16, -22, and -23) is located at 15926 Foothill Boulevard in the City of Fontana, San Bernardino County, California (see Figure 1 - Site Location Map). Based on our recent field investigation and site geologic mapping the site is generally vacant and undeveloped. Our review of Google Earth Pro (GEP, 2020) imagery and field work, indicates the property consists of a generally flat-lying terrain that varies in elevation from approximately ±1,308 feet MSL (Mean Sea Level) near the northern portion of the site to approximately ±1,294 feet MSL near the southern portion of the property. Therefore, overall relief is on the order of ±14 feet. Existing improvements onsite consist of a coupole of billboards, telephone poles and power lines parallel to W.O. SITE LOCATION MAP Figure 1 8027-A-SC SITE Base Map: TOPO!® ©2003 National Geographic, U.S.G.S. Fontana Quadrangle, California -- San Bernandino Co., 7.5 Minute, dated 1973. Base Map: Google Maps, Copyright 2021 Google, Map Data Copyright 2021 Google SITE 0 1000 2000 3000 4000 This map is copyrighted by Google 2021. It is unlawful to copy or reproduce all or any part thereof, whether for personal use or resale, without permission. All rights reserved. NOT TO SCALE GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 3 E. Foothill Blvd, temporary perimeter fencing, and sidewalks in the perimeter right of way. Vegetation onsite consists primarily of native grasses and weeds, with few trees and shrubs along the northern portions of the property line margin. PROPOSED DEVELOPMENT Based on a review of the conceptual site plan prepared by HPA (2020), it is our understanding that the proposed development of the ±10-acre site would consist of preparing the project site for a 423-unit, 2- to 4-story multi-family residential condominium complex, with an at grade, five (5) level parking structure, a swimming pool, courtyard, leasing lobby, fitness facilities, exterior landscaping, underground utility and street/roadway infrastructure improvements. Significant planed cuts and fills are not anticipated due the the relatively flat lying grade of the site. The multi-family residential dwellings are proposed as two- to four-story structures, with slab-on-grade/continuous footings, utilizing typical wood-frame and stucco type construction. Building loads are assumed to be typical for this type of relatively light multi-family residential structures, while the planned parking garage structure is anticipated to be more heavily loaded. Sewage disposal is to be accommodated by tying into the regional system. Proposed site improvements are indicated on the Geotechnical Map (Plate 1). FIELD STUDIES As indicated above, field studies conducted during our subsurface investigation consisted of geologic reconnaissance mapping and the excavation of ten (10) exploratory Test Pits throughout the site for evaluation of near-surface soil and geologic conditions, with two (2) of these test pits used for subsequent infiltration feasibility testing for proposed stormwater Best Management Practices (BMP) design purposes. The subsurface field exploration and infiltration testing was performed on December 9 and 10, 2020, respectively. The test pit excavations were logged by an engineering geologist from our firm who collected representative bulk and undisturbed ring samples for appropriate laboratory testing. The logs of the test pits are presented in Appendix B. The approximate locations of the exploratory test pits and infiltration test locations are presented on Plate 1 (Geotechnical Map) which uses HPA (2020) as a base map. REGIONAL AND SITE GEOLOGY Regional Geologic Setting The subject site is located near the northern margin of the Peninsular Ranges Geomorphic Province, which trends northwesterly, southerly of the transition and boundary with the Transverse Ranges Geomorphic Province, which trends east-west. The Peninsular Ranges GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 4 Geomorphic Province has a long and active geologic history. The Peninsular Ranges are characterized by large Mesozoic-age intrusive rocks, mantled by intruding volcanic, metasedimentary and sedimentary rocks. Lateral displacement and uplift of the region has occurred on a series of major, northwest-trending faults which are thought to be related to the San Andreas fault system. Some of these fault zones have remained active to the present time, including the Whittier, Elsinore, Raymond, and Chino Hills Blind Thrust fault zones and related faults. Intervening basin development has resulted in the accumulation of thick sequences of alluvium and basin fill, with alluvial deposits shed into these basins from the adjacent highlands. Local Geology Based on our subsurface investigation, and published geologic mapping by Morton (2003) and Morton & Miller (2006), the site is underlain by Holocene- and late Pleistocene-age young alluvial-fan deposits of Lytle Creek. The alluvial fan deposits are described as gray, unconsolidated, silty sands with cobbles and boulders, becoming coarser grained (cobbly and bouldery) northward. At this site, a thin veneer of colluvium and discontinuous deposits of undocumented fill appear to mantle the site. Site Geologic Units As observed during our recent subsurface investigation, the site geologic units include: surficial deposits of undocumented fill, surficial deposits of colluvium, underlain by Holocene- and late Pleistocene-age young alluvial fan deposits (Morton and Miller, 2006). The distribution of mappable units is shown on Plate 1. Supplemental soil descriptions are shown in the Test Pit Logs (Appendix B). The geologic units are generally described below (from youngest to oldest): Undocumented Fill (Map Symbol - afu) Thin, surficial deposits of undocumented fill were generally observed within the eastern half of the site, consisting of scattered dump fills and a somewhat linear embankment that may have been constructed as a diversionary water dike. These surficial soil deposits were found to generally consist of dark brown and dark yellowish brown silty sands and gravelly silty sands, that were observed to be dry, loose, and porous, with many rootlets, and some construction debris (i.e., concrete, pipe, etc.) locally within dump piles. These materials are considered compressible and potentially collapsible if left unmitigated, and therefore should be removed, cleaned of deleterious debris, and recompacted during site grading. Quaternary-Age Colluvium (Not Mapped) Surficial deposits of colluvium (topsoil) were encountered mantling the young alluvial fan deposits onsite. These surficial soil deposits were found to generally consist of gray brown, brown, and dark brown silty sand, that were observed to be dry, loose, and porous, GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 5 with few roots and many well rounded gravels and cobbles locally. These materials are considered compressible and potentially collapsible if left unmitigated, and therefore should be removed and recompacted during site grading. Holocene/Late Pleistocene-age Young Alluvial Fan Deposits (Map Symbol - Qyfl) As mapped by Morton (2003), Miller and Morton (2006), and as logged within the subsurface explorations, the site is underlain with young alluvial fan deposits consisting of discontinuous, thin near surface deposits of brown to yellowish brown, and dark yellow brown silty sand overlying brown, dark brown, dark yellowish brown, and yellowish brown sandy gravel to gravelly sand where gravels and cobble rock fragments are well rounded and comprise anywhere from about 30 to slightly over 50 percent of the soil mass. Near surface deposits, typically within about four (4) feet of surface grades are slightly moist, loose, and porous. At depth, alluvium becomes medium dense with no visible porosity. However, due to the relative lack of fines, the coarseness of the soil, and lack of cohesion, caving of the exploratory trench sidewalls was common. Based on our evaluation, the alluvial soils within about ±4 to ±5 feet of existing surface grades are considered compressible and potentially collapsible under proposed loading conditions, making it unsuitable for the support of settlement-sensitive improvements in its existing state. As such, these soils should be removed and recompacted, in areas proposed for settlement-sensitive improvements. Caving of near vertical trench sidewalls constructed in alluvium was prevalent and should be considered during trenching for underground improvements. GROUNDWATER Seeps, springs, or other indications of high regional groundwater were not noted on the subject property during the time of our field investigation (December, 2020). Based on our review of the California Department of Water Resources, Water Data Library (2021), groundwater within a nearby well (State Well #01505W06J001S, elevation of 1,361.5 feet MSL) located northeast of the site has varied in depth from about -591 to -609 feet below the ground surface (bgs), between 2010 and 2020, while an additional well (State Well #01S06W12P001S, elevation of 1210.63 feet MSL) located southeast of the site recorded depths to groundwater ranging from about -385 feet to -486 feet bgs between 1925 and 2017. Based on this data, and with an average site elevation of about 1,300 feet MSL, groundwater is anticipated to be on the order of greater than 400 feet beneath the site. A review of water levels in the vicinity over that last 20, and 95 years indicates water level fluctuations of about 20 feet, and 100 feet, respectively. Although regional groundwater should not be a factor in site development or underground utility installation, seepage may be encountered along fill contacts or throughout the site along with seasonal perched water. Seepage and a transient perched water table can also develop along, or near the contact between near surface fills, and the underlying native GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 6 soil. This may occur after heavy rains, as the result of irrigation practices, and/or other factors not evident at the time of our review, and may manifest after development. Although not anticipated, the need for localized subdrainage systems to control seepage and perched water may not be precluded. FAULTING AND REGIONAL SEISMICITY Local and Regional Faults Our review of Jennings and Bryant (2010), Miller (2003), and Morton and Miller (2006) indicates that there are no known faults crossing this site, and the site is not within an Alquist-Priolo Earthquake Fault Zone (California Geological Survey, [CGS] 2018). However, the site is situated in a region subject to strong earthquakes occurring along active faults. These faults include, but are not limited to: the San Jose, the San Andreas, the Cucamonga, the San Jacinto, and the Elsinore, Whittier, and Chino Hills Blind Thrust fault zones. The relationship of the location of the project area to these major mapped faults is indicated on the California Fault Map (Appendix C). According to Blake (2000a), the closest known active faults to the site are the San Jacinto-San Bernardino fault which is located at a distance of approximately 5.0 miles ([mi], ±8.0 kilometers [km]) from the site, the Cucamonga fault which is located at a distance of approximately ±6.5 miles ([mi], ±10.4 kilometers [km]) from the site, and the San Andreas-San Bernardino (M-1) fault which is located at a distance of approximately ±9.6 miles ([mi], ±15.4 kilometers [km]) from the site. Portions of these fault systems have demonstrated movement in the Holocene Epoch (i.e., last 11,700 years) and therefore, are located in an Alquist-Priolo Earthquake Fault Zone (CGS, 2018). Cao, et al. (2003) indicate that the closest fault, San Jacinto-San Bernardino fault zone is a “B” fault, wand is capable of producing a maximum magnitude (M ) 6.7 earthquake, while the wCucamonga fault is an “A” fault and is capable of producing a maximum magnitude (M ) 6.9 earthquake. However, the San Andreas-San Bernardino fault (“A” fault) is capable of wproducing a maximum magnitude (M ) 7.5 earthquake, and is considered the “design fault” for this site. The possibility of ground acceleration, or shaking at the site, may be considered as approximately similar to the Southern California region as a whole. An inactive northeast trending fault is located about 0.23 miles southeast of the site. Major active fault zones that may have a significant affect on the site, should they experience activity, are listed in Appendix C (modified from Blake, 2000a). The acceleration-attenuation relations of Bozorgnia, Campbell, and Niazi (1999), have been incorporated into EQFAULT (Blake, 2000a). For this study, peak horizontal ground accelerations anticipated at the site were determined based on the mean plus 1 - sigma attenuation curves developed by those authors. The EQFAULT computer program performs deterministic seismic hazard analyses using digitized California faults as earthquake sources. The program estimates the closest distance between each fault and GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 7 a given site. If a fault is found to be within a user-selected radius, the program estimates peak horizontal ground acceleration that may occur at the site from an upper bound ("maximum credible") earthquake on that fault. Site acceleration (g) is computed by user-selected acceleration-attenuation relations that are contained in EQFAULT. Based on the EQFAULT program, peak horizontal ground accelerations (deterministic acceleration values) from an upper bound event at the site may be on the order of 0.739g, or more. Historical Site Acceleration Historical site seismicity was evaluated with the acceleration-attenuation relations of Bozorgnia, Campbell, and Niazi (1999) and the computer program EQSEARCH (Blake, 2000b). This program was utilized to perform a search of historical earthquake records for magnitude 5.0 to 9.0 seismic events within a 100 km radius, between the years 1800 to August, 2018. Based on the selected acceleration-attenuation relation, a peak horizontal ground acceleration has been estimated, which may have affected the site during the specific seismic events in the past. Based on the available data and attenuation relationship used, the estimated maximum (peak) site acceleration during the period 1800 to August, 2018, was 0.475g. In addition, a seismic recurrence curve is also estimated/generated from the historical data (see Appendix C). Seismic Shaking Parameters The following tables summarize the site-specific design criteria obtained from the 2019 CBC, Chapter 16 Structural Design, Section 1613, Earthquake Loads for a Site Class of D, as determined by actual testing (see Appendix B). The computer program Seismic Design Maps, provided by the California Office of Statewide Health Planning and Development (OSHPD, 2020) has been utilized to aid in design (https://seismicmaps.org). The short spectral response utilizes a period of 0.2 seconds. 2019 CBC SEISMIC DESIGN PARAMETERS PARAMETER VALUE VALUE PER ASCE 7-16 2019 CBC OR REFERENCE Risk Category II -Table 1604.5 Site Class D -Section 1613.2.2/Chap. 20 ASCE 7-16 (p. 203-204) sSpectral Response - (0.2 sec), S 2.023 g -Section 1613.2.1 Figure 1613.2.1(1) 1Spectral Response - (1 sec), S 0.744 g -Section 1613.2.1 Figure 1613.2.1(2) aSite Coefficient, F 1.2 -Table 1613.2.3(1) GeoSoils, Inc. 2019 CBC SEISMIC DESIGN PARAMETERS PARAMETER VALUE VALUE PER ASCE 7-16 2019 CBC OR REFERENCE Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 8 vSite Coefficient, F null - see Section 11.48 ASCE 7-16 2.5 (Section 21.3)Table 1613.2.3(2) Maximum Considered Earthquake Spectral Response Acceleration MS(0.2 sec), S -1.201 g Section 1613.2.3 (Eqn 16-36) Maximum Considered Earthquake Spectral Response Acceleration M1(1 sec), S null - see Section 11.48 ASCE 7-16 1.202 g (Section 21.4)Section 1613.2.3 (Eqn 16-37) 5% Damped Design Spectral DSResponse Acceleration (0.2 sec), S -0.801 g Section 1613.2.4 (Eqn 16-38) 5% Damped Design Spectral D1Response Acceleration (1 sec), S null - see Section 11.48 ASCE 7-16 0.802 g (Section 21.4) Section 1613.2.4 (Eqn 16-39) MPGA - Probabilistic Vertical Ground Acceleration may be assumed as about 50% of these values. 1.044 g -ASCE 7-16 (Eqn 11.8.1) Seismic Design Category null - see Section 11.48 ASCE 7-16 D (Section 11.6) Section 1613.2.5/ASCE 7-16 (p. 85: Table 11.6-1 or 11.6-2) 1. FV = 2.5 S1>0.2 per Section 21.3, 2. SM1= (1.5)SD1 =(1.5)(0.802)=1.202 per Section 21.4 3. SD1 $ 0.2 = 0.802 $ 0.2 , per Section 11.6 site is in Risk Category D . GENERAL SEISMIC PARAMETERS PARAMETER VALUE Distance to Seismic Source 9.6 mi (15.4 km)(1)(2) Upper Bound Earthquake San Andreas (San Bernardino N)WM = 7.5 (1) - Cao, et al. (2003)(1) - Blake (2000)(2) Conformance to the criteria above for seismic design does not constitute any kind of guarantee or assurance that significant structural damage or ground failure will not occur in the event of a large earthquake. The primary goal of seismic design is to protect life, not to eliminate all damage, since such design may be economically prohibitive. Cumulative effects of seismic events are not addressed in the 2019 CBC (CBSC, 2019a) and regular wmaintenance and repair following locally significant seismic events (i.e., M 5.5) will likely be necessary, as is the case in all of Southern California. A summary of the seismic data is included in Appendix C. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 9 It is important to keep in perspective that in the event of a maximum probable or credible earthquake occurring on any of the nearby major faults, strong ground shaking would occur in the subject site's general area. Potential damage to any structure(s) would likely be greatest from the vibrations and impelling force caused by the inertia of a structure's mass. This potential would be no greater than that for other existing structures and improvements in the immediate vicinity. LIQUEFACTION POTENTIAL Liquefaction Liquefaction describes a phenomenon in which cyclic stresses, produced by earthquake-induced ground motion, create excess pore pressures in relatively cohesionless soils. These soils may thereby acquire a high degree of mobility, which can lead to vertical deformation, lateral movement, lurching, sliding, and as a result of seismic loading, volumetric strain and manifestation in surface settlement of loose sediments, sand boils and other damaging lateral deformations. This phenomenon occurs only below the water table, but after liquefaction has developed, it can propagate upward into overlying non-saturated soil as excess pore water dissipates. One of the primary factors controlling the potential for liquefaction is depth to groundwater. Typically, liquefaction has a relatively low potential at depths greater than 50 feet and is unlikely, and/or will produce vertical strains well below 1 percent for depths below 60 feet when relative densities are 40 to 60 percent and effective overburden pressures are two or more atmospheres (i.e., 4,232 psf [Seed, 2005]). The condition of liquefaction has two principal effects. One is the consolidation of loose sediments with resultant settlement of the ground surface. The other effect is lateral sliding. Significant permanent lateral movement generally occurs only when there is significant differential loading, such as fill or natural ground slopes within susceptible materials. The above conditions do not exist at the site. Liquefaction susceptibility is related to numerous factors and the following five conditions should be concurrently present for liquefaction to occur: 1) sediments must be relatively young in age and not have developed a large amount of cementation; 2) sediments must generally consist of medium- to fine-grained, relatively cohesionless sands; 3) the sediments must have low relative density; 4) free groundwater must be present in the sediment; and 5) the site must experience a seismic event of a sufficient duration and magnitude, to induce straining of soil particles. Only about one, to perhaps two, of these concurrently necessary conditions have the potential to affect the site in its current state. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 10 Seismic Densification Seismic densification is a phenomenon that typically occurs in low relative density granular soils (i.e., United States Soil Classification System [USCS] soil types SP, SM, and SC ) that are above the groundwater table. These unsaturated granular soils are susceptible if left in the original density (unmitigated), and are drier than the optimum moisture content (as defined by the ASTM D 1557). During seismically-induced ground shaking, these natural or artificial soils deform under loading and volumetric strain, potentially resulting in ground surface settlements. Some densification may occur on the adjoining unmitigated properties or areas of the subject site where remedial grading is not performed. This may influence improvements located above a 1:1 (horizontal:vertical [h:v]) projection up from the perimeter of the site or the limits of remedial grading. Special setbacks and/or foundations would be recommended for settlement-sensitive improvements within the influence of densifiable soils. Our evaluation assumes that the current offsite conditions will not be significantly modified by future grading at the time of the design earthquake, which is a reasonably conservative assumption. Summary It is the opinion of GSI that the susceptibility of the proposed sites to experience damaging deformations from seismically-induced liquefaction and densification is relatively low, owing to the recommended recompaction of near-surface low density soils (as discussed herein), the generally medium dense to dense nature of the young alluvial fan deposits that underlie the site at depth, and the depth to the regional groundwater table. Furthermore, the site is not located within in an area designated by San Bernardino County (SBC, 2010) as having a potential for liquefaction during a seismic event. Densification occurring on unmitigated, adjoining properties or portions of the subject site where remedial grading is not performed may affect the proposed improvements. Special setbacks for improvements may be necessary to mitigate densification. This would be best evaluated during the grading plan review stage. Other Geologic/Secondary Seismic Hazards The following list includes other geologic/seismic hazards that have been considered during our evaluation of the site. The hazards listed are considered negligible and/or mitigated as a result of site location, soil characteristics, foundation design, and typical site development procedures: •Subsidence •Dynamic Settlement •Surface Fault Rupture •Ground Lurching or Shallow Ground Rupture •Tsunami •Seiche GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 11 LABORATORY TESTING Classification Soils were classified visually according to the Unified Soils Classification System (USCS). The soil classifications are shown on the Test Pit Logs, Appendix B. Laboratory Standard The maximum density and optimum moisture content was determined for the major near surface soil type encountered in the exploratory test excavations. The laboratory standard used was ASTM D 1557. The moisture-density relationship obtained for the site soil is shown below: SOIL TYPE LOCATION AND DEPTH (ft.) MAXIMUM DRY DENSITY (pcf) OPTIMUM MOISTURE CONTENT (%) Yellowish brown well graded GRAVEL with sand and silt, GW-GM B-2 @ 0-8 123.8 7.8 Note: The percent gravel, and greater size fraction, in this sample was about ±49 percent of the total weight. Expansion Potential Expansion index (E.I.) testing and expansion potential classification were performed in general accordance with ASTM Standard D 4829 on a representative sample of the onsite soils collected from the field exploration. Additional E.I. testing should be conducted at the conclusion of site grading to further evaluate the preliminary test results obtained. The results of the expansion index testing are presented in the following table. SAMPLE LOCATION AND DEPTH (FT)EXPANSION INDEX EXPANSION POTENTIAL B-2 @ 0-2 <5 Very Low Direct Shear Test Shear tests were performed on representative relatively undisturbed and remolded samples of site soils in general accordance with ASTM Test Method D 3080 in a direct shear machine of the strain control type. The shear test results are presented in Appendix D, and summarized in the following table: GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 12 SAMPLE LOCATION AND DEPTH (FT) PRIMARY RESIDUAL COHESION (PSF) FRICTION ANGLE (DEGREES) COHESION (PSF) FRICTION ANGLE (DEGREES) B-2 @ 0-8 (composite) (Sample Remolded to 90 Percent of the Laboratory Standard [ASTM D 1557]) 31 35.9 8 34.3 Particle-Size Analysis A particle-size evaluation was performed on a representative soil sample in general accordance with ASTM D 422-63. The grain-size distribution curve is presented in Appendix D. The testing was utilized to evaluate the soil classification in accordance with the Unified Soil Classification System (USCS). The results of the particle-size evaluation (see Appendix D) indicate that the soils evaluated are silty sands (USCS Symbol GW-GM). Resistance Value Resistance value, or R-Value testing, was performed on a representative soil sample in accordance with CalTrans Test Method 301, and yielded a test result of R=80. The results of R-Value testing are presented in Appendix D. Saturated Resistivity, pH, and Soluble Sulfates, and Chlorides GSI conducted sampling of onsite earth materials for general soil corrosivity and soluble sulfates, and chlorides testing. The testing included evaluation of soil pH, soluble sulfates, chlorides, and saturated resistivity. Test results are presented in Appendix D and the following table: SAMPLE LOCATION AND DEPTH (FT)pH SATURATED RESISTIVITY (ohm-cm) SOLUBLE SULFATES (ppm) SOLUBLE CHLORIDES (ppm) B-1 Composite 6.7 27,000 10 non-detect Corrosion Summary Laboratory testing indicates that tested samples of the onsite soils are neutral with respect to soil acidity/alkalinity, are mildly corrosive to exposed, buried metals when saturated; present negligible (“not applicable” per ACI 318R-14) sulfate exposure to concrete; and negligible chloride exposure. Reinforced concrete mix design for foundations, slab-on-grade floors, and pavements should minimally conform to “Exposure Classes S0, GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 13 W0, and C1” in Table 19.3.1.1 of ACI 318R-14, as concrete would likely be exposed to moisture. It should be noted that GSI does not consult in the field of corrosion engineering. The client and project architect should agree on the level of corrosion protection required for the project and seek consultation from a qualified corrosion consultant, if warranted. Confirmation testing is recommended upon the completion of rough grading. PRELIMINARY SETTLEMENT ANALYSIS GSI has estimated the potential magnitudes of total settlement, differential settlement, and angular distortion for the design of foundations and improvements at the site. The analyses were based on laboratory test results and subsurface data collected from test excavations completed in preparation of this study. Site specific conditions affecting settlement potential include depositional environment, grain size and lithology of sediments, cementing agents, stress history, moisture history, material shape, density, void ratio, etc. Based on our review, site grading is anticipated to consist of minor cuts and fills on the order of 2 feet, or less, in thickness, With remedial grading, including removals and undercutting resulting in as-built fill thicknesses ranging from about 5 to 10 feet across the site. GSI understands that the project is in its conceptual stages. For the purpose of our geotechnical review and analyses, GSI has assumed that the foundations and slab design loads are typical for single-family wood-frame structures. For a typical four-story residential structure, wall loads are anticipated to be about 1.8 to 2.5 kips per linear foot of wall and 20 to 50 psf of concrete floor load. Isolated column loads are anticipated to be in the range of 10 to 50 kips. Parking structure loads should be provided to this office for review and supplemental analysis as plans are developed. Subsequent to the anticipated ground modification (i.e., remedial site grading), a total settlement (static, dynamic, and hydrocollapse) is anticipated to be at least 2½ inches, with differential settlement on the order of 1½ inches over a 50-foot span. This corresponds to an angular distortion estimated to be 1/400, or less. This level of deformation should be considered in foundation design and planning, on a preliminary basis. Further evaluation of settlement of structures needs to be performed once the project structural engineer provides soil bearing pressure plots. The settlement estimates do not preclude top of slope deformation (within code setback zones) or settlement due to fills that have been saturated from utility leaks, pool leaks, or excessive landscape irrigation. Post-construction settlement of the fill should be mitigated by proper foundation design, provided the design parameters, provided herein, are properly utilized in final design of the residential foundation systems and improvements. In addition to the above, the structural engineer should also consider estimated settlements due to short duration seismic loading and applicable load combinations, as required by the City/County and the 2019 CBC. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 14 PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS Based on our current field exploration, laboratory testing, and our engineering and geologic analyses, it is our opinion that the project site appears suited for the proposed multi-family residential condominium use from a soils engineering and geologic viewpoint. The recommendations presented below should be incorporated into the design, grading, and construction considerations. General 1.Soils engineering and compaction testing services should be provided during grading operations to assist the contractor in removing unsuitable soils and in his effort to compact the fill. 2.Geologic observations should be performed during grading to document and/or further evaluate geologic conditions. Although unlikely, if adverse geologic structures are encountered, supplemental recommendations and earthwork may be warranted. 3.In general, and based upon the available data to date, regional groundwater will not be a factor in site development or underground utility installation. However, seepage may be encountered along fill contacts or throughout the site along with seasonal perched water. Seepage and a transient perched water table can also develop along, or near, the contact between near surface fills and the underlying native soil, most likely after heavy rains, or due to irrigation practices and/or other factors not evident at the time of our review. This may occur after development. As such, the need for localized subdrainage systems for the control of seepage and perched water should be anticipated. 4.Based upon the proposed development plan and our field exploration, the young alluvial fan deposits throughout the site should be readily rippable with conventional earthwork equipment, in good working order. 5.Due to the non-cohesive nature of onsite materials, caving and sloughing should be anticipated in all subsurface excavations and trenching. Therefore, current local and state/federal safety ordinances for subsurface trenching should be enforced. 6.General earthwork, grading guidelines, and preliminary criteria are provided at the end of this report as Appendix F. Specific recommendations are provided below. Demolition/Grubbing 1.Any existing surface/subsurface structures (i.e., slabs, footings, block walls, underground utility systems, etc.), major vegetation, tree remains, and any GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 15 miscellaneous debris should be removed from the areas of proposed grading and disposed of offsite. 2.The project soils engineer should be notified of any previous foundation, sewer lines, septic tanks, leach fields, or other subsurface structures that are uncovered during the recommended removals, so that appropriate remedial recommendations can be provided. 3.Cavities or loose soils (including all removed footing excavations) remaining after demolition and site clearance should be cleaned out, observed by the soils engineer, processed, and replaced with fill that has been moisture conditioned to at least optimum moisture content and compacted to at least 90 percent of the laboratory standard, if not removed by proposed cuts. Treatment of Existing Ground 1.Removal of all near-surface disturbed soils, and near-surface weathered young alluvial fan deposits, will be necessary prior to fill placement in areas proposed for settlement-sensitive improvements. For preliminary planning purposes, removals are estimated to be on the order of ±4 to ±5 feet, with the potential for localized deeper removals. Actual removal depths will be evaluated in the field during site grading, using criteria of a minimum compaction of 85 percent of the laboratory standard, and/or 105 pcf, as suitable for left in place alluvium, below the above specified depth. 2.For foundation support with respect to the planned two- (2-) to four- (4-) story residential structures, a minimum fill blanket thickness of at least 4 feet, or at least 2 feet below the bottom of the footing (whichever is deeper) should be provided beneath foundation systems. As such, deeper foundation systems may require overexcavation/undercutting of the underlying soils, beyond the vertical limits of the typical removal depth. 3.For foundation support with respect to the parking structure, a minimum fill blanket thickness of at least five (5) feet is recommended beneath the bottom of footings. It should be noted that this could result in excavation depths of up to 10 feet below finish grades in the parking structure area. As such, deeper foundation systems may require overexcavation/undercutting of the underlying soils, beyond the vertical limits of the typical removal depth. 4.Based on the approximate location of existing offsite buildings, adjacent offsite improvements, and anticipated depths of remedial site grading (i.e., ±4 to ±5 feet), appropriate shoring and/or slot-cutting during site grading may be necessary to protect adjoining improvements. Native site soils are relatively cohesionless and caving should be anticipated during trenching. Underground construction should consider “Type B” soil conditions per OSHA trenching guidelines. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 16 5.Subsequent to the above removals, the upper 6 inches of the exposed subsoils should be scarified, brought to at least optimum moisture content, and recompacted to a minimum relative compaction of 90 percent of the laboratory standard, prior to additional fill placement. 6.The existing onsite earth materials, may be reused as compacted fill provided that major concentrations of vegetation, miscellaneous trash and debris, and concrete/block rubble are removed prior to or during fill placement. Fill Placement 1.Fill materials should be cleansed of major vegetation and debris prior to placement. 2.In general, fill materials should be brought to at least optimum moisture, placed in thin 6- to 8-inch lifts and mechanically compacted to obtain a minimum relative compaction of 90 percent of the laboratory standard. 3.Any import materials should be observed and determined suitable by the soils engineer prior to placement on the site. Foundation designs may be altered if import materials have greater sulfate and/or expansion values than the onsite materials encountered during our investigations. Preliminary Earthwork Factors Preliminary earthwork factors (shrinkage and bulking) for the subject property have been estimated based upon our field and laboratory testing, visual site observations, and experience in the site area. It is apparent that shrinkage would vary with depth and with areal extent over the site based on previous site use. Variables include vegetation, weed control, discing, and previous filling or exploring. However, all these factors are difficult to define in a three-dimensional fashion. Therefore, the information presented below represents average shrinkage/bulking values: Colluvium/Undocumented Fill ......................15% to 20% shrinkage Young Alluvial Fan Deposits .......................10% to 17% shrinkage An additional shrinkage factor item would include the removal of existing slabs, foundations, and root systems of individual large plants or trees. These plants and trees vary in size, but when pulled, may result in a loss of ½ to 1 cubic yard, to locally greater than 1 cubic yard of volume, respectively. The above facts indicate that earthwork balance for the site may be difficult to define and flexibility in design is essential to achieve a balanced end product. Subsidence due to equipment loadings (dynamic compaction) may be on the order of up to 0.10 feet, but will depend on haul routes, etc. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 17 PRELIMINARY RECOMMENDATIONS - FOUNDATIONS General Design options for using conventional, post tension, and mat slab foundations are provided in the following sections. Based on our analysis, and in consideration of the potential differential settlements from the combined effects of static, seismic, and hydrocollapse potentials, the use of post tension, and/or structural mat foundation systems should be considered. In the event that the information concerning the proposed development plan is not correct, or any changes in the design, location or loading conditions of the proposed structures are made, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and conclusions of this report are modified or approved in writing by this office. The information and recommendations presented in this section are not meant to supercede design by the project structural engineer or civil engineer specializing in structural design. Upon request, GSI could provide additional input/consultation regarding soil parameters, as related to foundation design. Recommendations by the project's design-structural engineer or architect, which may exceed the soils engineer's recommendations, should take precedence over the following minimum requirements. Final foundation design will be provided based on the expansion and corrosion potential of the near surface soils encountered at the conclusion of site grading. The proposed foundation systems should be designed and constructed in accordance with current standards of practice, the guidelines contained within the 2019 California Building Code ([2019 CBC], California Building Standards Commission [CBSC], 2019a), the ACI (2014a, 2014b), and the differential settlement and expansion potential values anticipated. The onsite soil expansion potentials for the project have been evaluated to be very low (E.I. of 0 to 21), as defined by the 2019 CBC (CBSC, 2019a). GSI understands that the project is still in its conceptual design stages. For the purpose of our geotechnical review and analyses, GSI has assumed that the foundations and slab design loads are typical for multi-family wood-frame structures. For a typical four-story residential structure, wall loads are anticipated to be approximately 1.8 to 2.5 kips per linear foot of wall and 20 to 50 psf of concrete floor load. Isolated column loads are anticipated to be in the range of 10 to 50 kips. Based upon the design configurations evaluated, site geologic conditions, and the results of our settlement analysis, the following preliminary settlement design values should be utilized for planning and design of onsite structural improvements. Parking structure loads should be provide to this office for review, as plans are developed. All footings are recommended to embed into compacted fill, as indicated in this report. The foundation design recommendations contained in this report may be modified once GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 18 actual loading conditions have been provided for GSI review. All foundations should be designed using, at a minimum, the parameters and static settlements described herein. All foundations should be evaluated for seismic deformations described herein. Design options using conventional, post tension, and mat slab foundations are provided in the following sections, and are not intended to preclude the transmission of water or water vapor through the foundations or slabs. Further discussion and recommendations are provided within the soil moisture transmission considerations section of this report. In addition to the above, the structural engineer should also consider estimated settlements due to short duration seismic loading and applicable load combinations, as required by the controlling authorities and the 2019 CBC (CBSC, 2019a). A supplemental analysis with respect to the planned parking structure is recommended once preliminary design loads are provided. Preliminary Conventional Foundation Design General The following preliminary foundation construction recommendations are presented as a minimum criteria from a soils engineering viewpoint, where the planned improvements are underlain by at least 7 feet of non-detrimentally expansive soils (i.e., E.I.<21 and P.I. <15). Although not anticipated, should foundations be underlain by (detrimentally) expansive soils, they will require specific design to mitigate expansive soil effects as required in Sections 1808.6.1 or 1808.6.2 of the 2019 CBC. As previously noted, once foundation loads for the proposed parking structure are made available, a supplemental design review is recommended. Based on our analysis, and in consideration of the sites settlement potential, the following design and construction recommendations for “conventional” type foundations are provided as minimums, from a geotechnical viewpoint. 1.Conventional foundation systems should be designed and constructed in accordance with guidelines presented in the 2019 CBC (CBSC, 2019a). 2.Based on the anticipated foundation loads and preliminary design information, building loads may be supported on continuous or isolated spread footings designed in accordance with the following recommendations. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 19 ALLOWABLE BEARING VALUES FOR FOOTINGS ON COMPACTED FILL DEPTH BELOW LOWEST ADJACENT FINISHED GRADE (INCHES) ALLOWABLE BEARING CAPACITY FOR SPREAD FOOTINGS (MINIMUM WIDTH = 4 FEET) ALLOWABLE BEARING CAPACITY FORWALL FOOTINGS (MINIMUM WIDTH = 4 FEET) 36 3.5 ksf 3.5 ksf 48 4.0 ksf 4.0 ksf 60 4.5 ksf 4.5 ksf * These allowable bearing values can be achieved only with compacted fill soils at least 5 feet below the parking garage structure footing. The above values are for dead plus live loads and may be increased by one-third for short-term wind or seismic loads. Where column or wall spacings are less than twice the width of the footing, some reduction in bearing capacity may be necessary to compensate for the effects of footings with shared bearing soils. GSI should review the foundation plans and overlying building load patterns and evaluate this potential with the structural consultant. Reinforcement should be designed in accordance with local codes and structural considerations. 3.Foundation embedment depth excludes concrete slabs-on-grade, and/or slab underlayment. Foundations should bear entirely on a minimum 5-foot thick layer of approved engineered fill overlying suitable formation (i.e., dense older alluvium, or bedrock). All isolated pad footings should be tied to the perimeter foundation in at least one direction to reduce the potential for lateral drift. 4.For foundations deriving passive resistance from engineered fill, prepared in accordance with the recommendations provided in this report, a pressure of 275 pcf may be used if the footing face is embedded entirely in engineered fill, and the embedment is 24 to 48 inches. 5.The upper 6 inches of passive pressure should be neglected if not confined by slabs or pavement. 6.For lateral sliding resistance, a 0.35 coefficient of friction may be utilized for a concrete to soil contact when multiplied by the dead load. 7.When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. 8.Although not anticipated, given our understanding of the proposed development, all footing setbacks from slopes should comply with Figure 1808.7.1 of the 2019 CBC. GSI recommends a minimum horizontal setback distance of 7 feet as GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 20 measured from the bottom, outboard edge of the footing to the slope face. Foundations should also extend below a 1:1 (h:v) projection up from the bottom outside edge of remedial grading excavations. 9.Footings for structures adjacent to retaining/privacy walls should be deepened so as to extend below a 1:1 projection from the heel of the wall. Alternatively, walls may be designed to accommodate structural loads from buildings or appurtenances as described in the “Retaining Wall” section of this report. 10.Footings constructed below a 1:1 projection from adjacent property lines should be designed for any applicable surcharge. PRELIMINARY FOUNDATION CONSTRUCTION RECOMMENDATIONS The following foundation construction recommendations are presented as a minimum criteria from a soils engineering viewpoint, where the planned improvements are underlain by at least 7 feet of non-detrimentally expansive soils (i.e., E.I.<21 and a plasticity index [P.I.] <15, as defined in Section 1803.5.3 of the 2019 CBC). Actual designs will be dependant on structural loads and the engineer’s evaluation of differential settlement. 1.Exterior and interior footings should be founded into approved engineered fill, as indicated in the previous “Preliminary Foundation Design” section of this report. Reinforcement should be designed in accordance with local codes and structural considerations, and per the project structural engineer. At a minimum, all footings should be reinforced with four No. 4 reinforcing bars, two placed near the top and two placed near the bottom of the footing. Reinforcement of pad footings should be provided by the project’s structural engineer. 2.All interior and exterior column footings, and perimeter wall footings, should be tied together via grade beams in at least two directions. The grade beam should be at least 24 inches square in cross section, and the base of the reinforced grade beam should be at the same elevation as the adjoining footings. At a minimum, grade beams should be minimally reinforced with four No. 4 reinforcing bars, two placed near the top and two placed near the bottom of the footing. Reinforcement should be designed in accordance with local codes and structural considerations, and per the project’s structural engineer. 3.A grade beam, reinforced as previously recommended, and at least 24 inches square, should be provided across large (garage) entrances. The base of the reinforced grade beam should be at the same elevation as the adjoining footings. 4.Non-vehicular slab-on-grade floors should have a minimum thickness of 5 inches with steel reinforcement consisting of No. 3 reinforcing bars positioned at 18 inches GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 21 on center in two perpendicular directions (i.e., long axis and short axis). All slab reinforcement should be supported to ensure proper mid-slab height positioning during placement of the concrete. "Hooking" of reinforcement is not an acceptable method of positioning. The actual thickness and steel reinforcement for concrete slab-on-grade floors should be determined by the project structural engineer, based on the anticipated loading conditions and building use. However, the slab thickness and steel reinforcement recommendations, contained herein, are considered minimum guidelines. 5.The project structural engineer should consider the use of transverse and longitudinal control joints to help control slab cracking due to concrete shrinkage or expansion. Two of the best ways to control this movement are: 1) add a sufficient amount of reinforcing steel to increase the tensile strength of the slab; and 2) provide an adequate amount of control and/or expansion joints to accommodate anticipated concrete shrinkage and expansion. Transverse and longitudinal crack control joints should be spaced no more than 13 feet on center and constructed to a minimum depth of T/4, where T equals the slab thickness in inches. Per Portland Cement Association (PCA) and ACI guidelines, joints are commonly spaced at distances equal to 24 to 30 times the slab thickness. Joint spacing that is greater than 15 feet require the use of load transfer devices (dowels or diamond plates). 6.Reinforced concrete mix design should conform to recommendations contained in the “Soil Moisture Transmission Considerations” section of this report. 7.Specific slab subgrade pre-soaking is recommended for these soil conditions. Prior to the placement of underlayment sand and vapor retarder, GSI recommends that the slab subgrade materials be moisture conditioned to at least optimum moisture content to a minimum depth of 12 inches. Slab subgrade pre-soaking should be evaluated by the geotechnical consultant within 72 hours of the placement of the underlayment sand and vapor retarder. 8.Soils generated from footing excavations to be used onsite should be compacted to a minimum relative compaction of 90 percent of the laboratory standard (ASTM D 1557), whether the soils are to be placed inside the foundation perimeter or in other areas of the site. This material must not alter positive drainage patterns that direct drainage away from the structural areas and toward the street. Post-Tensioned Foundations Post-tension foundations may be used to mitigate the damaging effects of differential settlement on the planned residential foundations and slab-on-grade floors. The post-tension foundation designer may elect to exceed these minimal recommendations to increase slab stiffness performance. Post-tension (PT) design may be either ribbed or GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 22 mat-type. The latter is also referred to as uniform thickness foundation (UTF). The use of a UTF is an alternative to the traditional ribbed-type. The UTF offers a reduction in grade beams. That is to say a UTF typically uses a single perimeter grade beam and possible “shovel” footings, but has a thicker slab than the ribbed-type. The information and recommendations presented in this section are not meant to supercede design by a registered structural engineer or civil engineer qualified to perform post-tensioned design. Post-tensioned foundations should be designed using sound engineering practice, and be in accordance with local and 2019 CBC code requirements. Upon request, GSI can provide additional data/consultation regarding soil parameters as related to post-tensioned foundation design. From a soil expansion/shrinkage standpoint, a common contributing factor to distress of structures using post-tensioned slabs is a "dishing" or "arching" of the slabs. This is caused by the fluctuation of moisture content in the soils below the perimeter of the slab primarily due to onsite and offsite irrigation practices, climatic and seasonal changes, and the presence of expansive soils. When the soil environment surrounding the exterior of the slab has a higher moisture content than the area beneath the slab, moisture tends to migrate inward, underneath the slab edges to a distance beyond the slab edges referred to as the moisture variation distance. When this migration of water occurs, the volume of the soils beneath the slab edges expands and causes the slab edges to lift in response. This is referred to as an edge-lift condition. Conversely, when the outside soil environment is drier, the moisture transmission regime is reversed and the soils underneath the slab edges lose their moisture and shrink. This process leads to dropping of the slab at the edges, which leads to what is commonly referred to as the center lift condition. A well-designed, post-tensioned slab having sufficient stiffness and rigidity provides a resistance to excessive bending that results from non-uniform swelling and shrinking slab subgrade soils, particularly within the moisture variation distance, near the slab edges. Other mitigation techniques typically used in conjunction with post-tensioned slabs consist of a combination of specific soil pre-saturation and the construction of a perimeter "cut-off" wall grade beam. Soil pre-saturation consists of moisture conditioning the slab subgrade soils prior to the post-tension slab construction. This effectively reduces soil moisture migration from the area located outside the building toward the soils underlying the post-tension slab. Perimeter cut-off walls are thickened edges of the concrete slab that impedes both outward and inward soil moisture migration. Slab Subgrade Pre-Soaking Pre-moistening of the slab subgrade soil is recommended. The moisture content of the subgrade soils should be equal to or greater than optimum moisture to a depth equivalent to the perimeter grade beam or cut-off wall depth in the slab areas (typically 12 inches for very low expansive soil conditions). GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 23 Pre-moistening and/or pre-soaking should be evaluated by the soils engineer 72 hours prior to vapor retarder placement. In summary: EXPANSION INDEX PAD SOIL MOISTURE CONSTRUCTION METHOD SOIL MOISTURE RETENTION Very Low to Low (0-50) Upper 12 inches of pad soil moisture 2 percent over optimum (or 1.2 times) Wetting and/or reprocessing Periodically wet or cover with plastic after trenching. Evaluation 72 hours prior to placement of concrete. Perimeter Cut-Off Walls Perimeter cut-off walls should be at least 12 inches deep for very low to low expansive soil conditions. The cut-off walls may be integrated into the slab design or independent of the slab. The cut-off walls should be a minimum of 6 inches thick (wide). The bottom of the perimeter cut-off wall should be designed to resist tension, using cable or reinforcement per the structural engineer. Post-Tensioned Foundation Design The following recommendations for design of post-tensioned slabs have been prepared in general compliance with the requirements of the recent Post Tensioning Institute’s (PTI’s) publication titled “Standard Requirements for Design and Analysis of Shallow Post-tensioned Concrete Foundations on Expansive Soils” (PTI, 2012), together with its subsequent errata (PTI, 2013 and 2014). Soil Support Parameters The recommendations for soil support parameters have been provided based on the typical soil index properties for soils that are very low to low in expansion potential. The soil index properties are typically the upper bound values based on our experience and practice in the southern California area. The following table presents suggested minimum coefficients to be used in the Post-Tensioning Institute design method. Thornthwaite Moisture Index -20 inches/year Correction Factor for Irrigation 20 inches/year Depth to Constant Soil Suction 7 feet or overexcavation depth, whichever is greater Constant soil Suction (pf)3.6 Moisture Velocity 0.7 inches/month Plasticity Index (P.I.)*15-45 * - The effective plasticity index should be evaluated for the upper 7 to 15 feet of earth materials. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 24 Based on the above, the recommended soil support parameters are tabulated below: DESIGN PARAMETERS VERY LOW TO LOW EXPANSION (E.I. = 0-50) me center lift 9.0 feet me edge lift 5.2 feet my center lift 0.4 inches my edge lift 0.7 inch Bearing Value 1,000 psf(1) Lateral Pressure 250 psf Subgrade Modulus (k)100 pci/inch Minimum Perimeter Footing Embedment 12 inches(2) Internal bearing values within the perimeter of the post-tension slab may be increased to 1,500 psf for a minimum(1) embedment of 12 inches, then by 20 percent for each additional foot of embedment to a maximum of 2,500 psf. As measured below the lowest adjacent compacted subgrade surface without landscape layer or sand(2) underlayment. Note: The use of open bottomed raised planters adjacent to foundations will require more onerous design parameters. The parameters are considered minimums and may not be adequate to represent all expansive soils and site conditions such as adverse drainage and/or improper landscaping and maintenance. The above parameters are applicable provided the structure has positive drainage that is maintained away from the structure. In addition, no trees with significant root systems are to be planted within 15 feet of the perimeter of foundations. Therefore, it is important that information regarding drainage, site maintenance, trees, settlements, and effects of expansive soils be passed on to future all interested/affected parties. The values tabulated above may not be appropriate to account for possible differential settlement of the slab due to other factors, such as excessive settlements. If a stiffer slab is desired, alternative Post-Tensioning Institute ([PTI] third edition) parameters may be recommended. Mat Foundations In lieu of using a post-tensioned foundation to resist differential settlement and/or expansive soil effects, the Client may consider a mat foundation which uses steel bar reinforcement instead of post-tensioned cables. The structural engineer may supercede the following recommendations based on the planned building loads and use. Wire Reinforcement Institute (WRI, 2016) methodologies for design may be used. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 25 Mat Foundation Design The design of mat foundations should incorporate the vertical modulus of subgrade reaction. This value is a unit value for a 1-foot square footing and should be reduced in accordance with the following equation when used with the design of larger foundations. This assumes that the bearing soils will consist of engineered fills with an average relative compaction of 90 percent of the laboratory (ASTM D 1557). S where: K = unit subgrade modulus R K = reduced subgrade modulus B = foundation width (in feet) SThe modulus of subgrade reaction (K ) and effective plasticity index (PI) to be used in mat foundation design for various expansive soil conditions are presented in the following table. VERY LOW TO LOW EXPANSION (E.I. = 0-50) SK =100 pci/inch, PI <15 Reinforcement bar sizing and spacing for mat slab foundations should be provided by the structural engineer. Mat slabs may be uniform thickness foundations (UTF) or incorporate the use of edge footings for moisture cut-off barriers as recommended herein for post-tension foundations. Edge footings should be a minimum of 6 inches thick. The bottom of the edge footing should be designed to resist tension, using reinforcement per the structural engineer. The need and arrangement of interior grade beams (stiffening beams) will be in accordance with the structural consultant’s recommendations. The recommendations for a mat type of foundation assume that the soils below the slab are compacted fill. The parameters herein are to mitigate the effects of expansive soils and should be modified to mitigate the effects of the total and differential settlements reported in the “Foundation and Improvement Settlements” section of this report. Specific pre-moistening/pre-soaking and moisture testing of the slab subgrade are recommended, as previously provided in this report. Slab subgrade moisture conditioning/pre-soaking should conform to the recommendations previously provided for post-tension foundation systems. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 26 Confirmation Testing for Final Foundation Design Following the completion of site grading, the expansion index, subgrade modulus, and corrosion potential of soils exposed near finish pad grades should be re-evaluated. Although not anticipated, the results of the recommended testing may require amendments to these preliminary recommendations presented herein. SOIL MOISTURE TRANSMISSION CONSIDERATIONS GSI has evaluated the potential for vapor or water transmission through the slabs, in light of typical residential floor coverings and improvements. Please note that typical slab moisture emission rates range from about 2 to 27 lbs/24 hours/1,000 square feet from a normal slab (Kanare, 2005), while floor covering manufacturers generally recommend about 3 lbs/24 hours as an upper limit. The recommendations in this section are not intended to preclude the transmission of water or vapor through the foundation or slabs. Foundation systems and slabs shall not allow water or water vapor to enter into the structure so as to cause damage to another building component or to limit the installation of the type of flooring materials typically used for the particular application (State of California, 2020). These recommendations may be exceeded or supplemented by a water “proofing” specialist, project architect, or structural consultant. Thus, the client will need to evaluate the following in light of a cost versus benefit analysis (owner expectations and repairs/replacement), along with disclosure to all interested/affected parties. Considering the E.I. test results, the anticipated typical water vapor transmission rates, floor coverings, and improvements (to be chosen by the homeowner) that can tolerate vapor transmission rates without significant distress, the following alternatives are provided: •Concrete slabs should be thicker. •Concrete slab underlayment should consist of a 15-mil vapor retarder, or equivalent, with all laps sealed per the 2019 CBC and the manufacturer’s recommendation. The vapor retarder should comply with the ASTM E 1745 - Class A or B criteria, and be installed in accordance with ACI 302.1R-04. •The 15-mil vapor retarder (ASTM E 1745 - Class A or B) shall be installed per the recommendations of the manufacturer, including all penetrations (i.e., pipe, ducting, rebar, etc.). •Concrete slabs, including garages, shall be underlain by 2 inches of clean, washed sand (SE>30) above a 15 mil vapor retarder (ASTM E 1745 - Class A or Class B, per Engineering Bulletin 119 [Kanare, 2005]). The vapor retarder shall in-turn, be underlain by 2 inches of sand (SE>30) placed directly on the prepared, moisture conditioned, subgrade. The vapor retarder should be sealed to provide a GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 27 continuous retarder under the entire slab and should be installed per the recommendations of the manufacturer, including all penetrations (i.e., pipe, ducting, rebar, etc.). The manufacturer shall provide instructions for lap sealing, including minimum width of lap, method of sealing, and either supply or specify suitable products for lap sealing (ASTM E 1745), and per code. ACI 302.1R-04 (2011) states “If a cushion or sand layer is desired between the vapor retarder and the slab, care must be taken to protect the sand layer from taking on additional water from a source such as rain, curing, cutting, or cleaning. Wet cushion or sand layer has been directly linked in the past to significant lengthening of time required for a slab to reach an acceptable level of dryness for floor covering applications.” Therefore, additional observation and/or testing will be necessary for the cushion or sand layer for moisture content, and relatively uniform thicknesses, prior to the placement of concrete. •Concrete should have a maximum water/cement ratio of 0.50. This does not supercede Table 19.3.2.1 of the ACI (2014a) for corrosion or other corrosive requirements. Additional concrete mix design recommendations should be provided by the structural consultant and/or waterproofing specialist. Concrete finishing and workablity should be addressed by the structural consultant and a waterproofing specialist. •Where slab water/cement ratios are as indicated herein, and/or admixtures used, the structural consultant should also make changes to the concrete in the grade beams and footings in kind, so that the concrete used in the foundation and slabs are designed and/or treated for more uniform moisture protection. •The owner(s) should be specifically advised which areas are suitable for tile flooring, vinyl flooring, or other types of water/vapor-sensitive flooring and which are not suitable. In all planned floor areas, flooring shall be installed per the manufactures recommendations. •Additional recommendations regarding water or vapor transmission should be provided by the architect/structural engineer/slab or foundation designer and should be consistent with the specified floor coverings indicated by the architect. Regardless of the mitigation, some limited moisture/moisture vapor transmission through the slab should be anticipated. Construction crews may require special training for installation of certain product(s), as well as concrete finishing techniques. The use of specialized product(s) should be approved by the slab designer and water-proofing consultant. A technical representative of the flooring contractor should review the slab and moisture retarder plans and provide comment prior to the construction of the foundations or improvements. The vapor retarder contractor should have representatives onsite during the initial installation. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 28 INFILTRATION FEASIBILITY TESTING In general accordance with guidelines of San Bernardino County (SBC, 2013), infiltration testing was conducted onsite during our field investigation. The approximate locations of the infiltration tests are provided on Plate 1 (Geotechnical Map, Test Pits TP-9 and TP-10). The infiltration testing was conducted within the native young alluvial fan deposits that underlie the site to evaluate site conditions with respect to the proposed stormwater BMP’s that will retain and filter onsite storm water. Percolation/infiltration testing was performed in general conformance with SBC (2013) guidelines for such testing. The field infiltration testing was performed by an engineering geologist from our firm. Logs of the excavations (TP-9 and TP-10) are presented in Appendix B and the field percolation/infiltration data are presented in Appendix E. Procedures for testing are outlined briefly below: Percolation Test Procedures Test Borings:1. Diameter - 8 to 10 inches. 2.After the removal of loose materials, 2 inches of gravel was placed on the bottom of each test cup. 3. A perforated pipe was then installed within each test location to facilitate accurate field measurements and prevent caving during the pre-soak period and subsequent testing. Pre-Soaking:After the installation of the perforated pipes, an inverted 5-gallon bottle of clear water was utilized to fill the test cups. Water was observed to completely seep into the ground while the tester was present. Sandy Soil Test:During the sandy soil test period, two (2) consecutive measurements were conducted at each test location at intervals of approximately 45 minutes or less. All water added to the soil seeped away during each of the two (2) test measurements within the percolation test locations, therefore testing was initiated the following the pre-soak period at these locations. Testing:After required pre-soak period, and due to the rapid infiltration of water into the soil, percolation testing measurements were made the same day. A column of clear water was re-established within each of the test locations. The drop in water level was measured from a fixed reference point, refilling after each test measurement. For each test, a series of test measurements were taken for a minimum of six (6) hours, at time intervals of less than 10 minutes. Accuracy:All test measurements were read to the nearest c-inch. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 29 Test Results:Calculations from our field testing indicate percolation rates of between 0.5 and 0.75 minutes/inch. Per the SBC (2013) guidelines, the percolation rates obtained were then converted to infiltration rates utilizing the “Porchet Method,” to be utilized by the design engineer for appropriate sizing of the basin (SBC, 2013). The converted infiltration rates obtained varied between 19.5 and 32.4 inches/hour, with an average of about 25.9 inches/hour. The converted infiltration rates, along with the formulas utilized, and the “factor of safety” work sheet are presented in Appendix E. Not the same as Exec. Summary Page Three ONSITE INFILTRATION-RUNOFF RETENTION SYSTEMS Since onsite infiltration-runoff retention systems (OIRRS) are planned for Best Management Practices (BMP’s) or Low Impact Development (LID) principles for the project (i.e., stormwater chambers), certain guidelines must be followed in the planning, design, and construction of such systems. Such facilities, if improperly designed or implemented without consideration of the geotechnical aspects of site conditions, can contribute to flooding, saturation of bearing materials beneath site improvements, slope instability, and possible concentration and contribution of pollutants into the groundwater or storm drain and/or utility trench systems. A key factor in these systems is the infiltration rate (often referred to as the percolation rate) which can be ascribed to, or determined for, the earth materials within which these systems are installed. Additionally, the infiltration rate of the designed system (which may include gravel, sand, mulch/topsoil, or other amendments, etc.) will need to be considered. The project infiltration testing is very site specific, any changes to the location of the proposed OIRRS and/or estimated size of the OIRRS, may require additional infiltration testing. Some of the methods which are utilized for onsite infiltration include percolation basins, dry wells, bio-swale/bio-retention, permeable pavers/pavement, infiltration trenches, filter boxes and subsurface infiltration galleries/chambers. Some of these systems are constructed using native and import soils, perforated piping, and filter fabrics while others employ structural components such as stormwater infiltration chambers and filters/separators. Every site will have characteristics which should lend themselves to one or more of these methods; but, not every site is suitable for OIRRS. In practice, OIRRS are usually initially designed by the project design civil engineer. Selection of methods should include (but should not be limited to) review by licensed professionals including the geotechnical engineer, hydrogeologist, engineering geologist, project civil engineer, landscape architect, environmental professional, and industrial hygienist. Applicable governing agency requirements should be reviewed and included in design considerations. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 30 The following geotechnical guidelines should be considered when designing onsite infiltration-runoff retention systems: •It is not good engineering practice to allow water to saturate soils, especially near slopes or improvements. However, the controlling agency/authority is now requiring this for OIRRS purposes on many projects. •Where possible, infiltration system design should be based on actual infiltration testing results/data, preferably utilizing double-ring infiltrometer testing (ASTM D 3385) to determine the infiltration rate of the earth materials being contemplated for infiltration. •Wherever possible, infiltration systems should not be installed within ±50 feet of the tops of slopes steeper than 15 percent or within H/3 from the tops of slopes (where H equals the height of slope). •Impermeable liners used in conjunction with basins should consist of a 30-mil polyvinyl chloride (PVC) membrane that is covered by a minimum of 12-inches of clean soil, free from rocks and debris, at a maximum inclination of 4:1 (h:v), and meets the following minimum specifications: Specific Gravity (ASTM D792): 1.2 (g/cc [min.]); Tensile (ASTM D882): 73 (lb/in-width [min.]); Elongation at Break (ASTM D882): 380 (% [min.]); Modulus (ASTM D882): 30 (lb/in-width [min.]); and Tear Strength (ASTM D1004): 8 (lbs [min.]); Seam Shear Strength (ASTM D882) 58.4 (lb/in [min.]); Seam Peel Strength (ASTM D882) 15 (lb/in [min]). •Wherever possible, infiltrations systems should not be placed within a distance of H/2 from the toes of slopes (where H equals the height of slope). •The landscape architect should be notified of the location of the proposed OIRRS. If landscaping is proposed within the OIRRS, consideration should be given to the type of vegetation chosen and their potential effect upon subsurface improvements (i.e., some trees/shrubs will have an effect on subsurface improvements with their extensive root systems). Over-watering landscape areas above, or adjacent to, the proposed OIRRS could adversely affect performance of the system. •Areas adjacent to, or within, the OIRRS that are subject to inundation should be properly protected against scouring, undermining, and erosion, in accordance with the recommendations of the design engineer. •If subsurface infiltration galleries/chambers are proposed, the appropriate size, depth interval, and ultimate placement of the detention/infiltration system should be evaluated by the design engineer, and be of sufficient width/depth to achieve GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 31 optimum performance, based on the infiltration rates provided. In addition, proper debris filter systems will need to be utilized for the infiltration galleries/chambers. Debris filter systems will need to be self cleaning and periodically and regularly maintained on a regular basis. Provisions for the regular and periodic maintenance of any debris filter system is recommended and this condition should be disclosed to all interested/affected parties. •Infiltrations systems should not be installed within ±8 feet of building foundations utility trenches, and walls, or a 1:1 (horizontal to vertical [h:v]) slope (down and away) from the bottom elements of these improvements. Alternatively, deepened foundations and/or pile/pier supported improvements may be used. •Infiltrations systems should not be installed adjacent to pavement and/or hardscape improvements. Alternatively, deepened/thickened edges and curbs and/or impermeable liners may be utilized in areas adjoining the OIRRS. •As with any OIRRS, localized ponding and groundwater seepage should be anticipated. The potential for seepage and/or perched groundwater to occur after site development should be disclosed to all interested/affected parties. •Installation of infiltrations systems should avoid expansive soils (Expansion Index [E.I.] $51) or soils with a relatively high plasticity index (P.I. > 20). •Infiltration systems should not be installed where the vertical separation of the groundwater level is less than ±10 feet from the base of the system. •Where permeable pavements are planned as part of the system, the site Traffic Index (T.I.) Should be less than 25,000 Average Daily Traffic (ADT), as recommended in Allen, et al. (2011). •Infiltration systems should be designed using a suitable factor of safety (FOS) or reduction factor (RF) to account for uncertainties in the known infiltration rates (as generally required by the controlling authorities), and reduction in performance over time. •As with any OIRRS, proper care will need to provided. Best management practices should be followed at all times, especially during inclement weather. Provisions for the management of any siltation, debris within the OIRRS, and/or overgrown vegetation (including root systems) should be considered. An appropriate inspection schedule will need to adopted and provided to all interested/affected parties. •Any designed system will require regular and periodic maintenance, which may include rehabilitation and/or complete replacement of the filter media (e.g., sand, GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 32 gravel, filter fabrics, topsoils, mulch, etc.) or other components utilized in construction, so that the design life exceeds 15 years. Due to the potential for piping and adverse seepage conditions, a burrowing rodent control program should also be implemented onsite. •All or portions of these systems may be considered attractive nuisances. Thus, consideration of the effects of, or potential for, vandalism should be addressed. •Newly established vegetation/landscaping (including phreatophytes) may have root systems that will influence the performance of the OIRRS or nearby LID systems. •The potential for surface flooding, in the case of system blockage, should be evaluated by the design engineer. •Any proposed utility backfill materials (i.e., inlet/outlet piping and/or other subsurface utilities) located within or near the proposed area of the OIRRS may become saturated. This is due to the potential for piping, water migration, and/or seepage along the utility trench line backfill. If utility trenches cross and/or are proposed near the OIRRS, cut-off walls or other water barriers will need to be installed to mitigate the potential for piping and excess water entering the utility backfill materials. Planned or existing utilities or drains may also be subject to piping of fines into open-graded gravel backfill layers unless separated from overlying or adjoining OIRRS by geotextiles and/or slurry backfill. •The use of OIRRS above existing utilities that might degrade/corrode with the introduction of water/seepage should be avoided. PRELIMINARY WALL DESIGN PARAMETERS General Based on our review (see Appendix A), the majority of onsite earth materials (disturbed soils and alluvial fan deposits) are derived from weathering of plutonic and sedimentary rocks which exhibit a very low expansion potential (E.I. 0 - 20). These materials appear to predominantly consist of silty sands with minor amounts of clay content. Due to the variability of silt and clay content within earth materials at the site, the native soil parameters may be non-uniform and therefore the recommendations provided herein consider these effects. Recommendations for the design and construction of conventional masonry retaining walls are provided herein. Recommendations for specialty walls (i.e., crib, earthstone, geogrid, etc.) can be provided upon request, and would be based on site specific conditions. If walls allow water to accumulate in the backfill or at their toe via a stormwater chamber, the water should be conveyed via a non-erosive device to an appropriate inlet, per the recommendations of the design civil engineer. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 33 Conventional Retaining Walls The design parameters provided below assume that either very low expansive soils (typically Class 2 permeable filter material or Class 3 aggregate base) or native onsite materials with an expansion index up to a maximum E.I. of 50 are used to backfill any retaining wall. The type of backfill (i.e., select or native), should be specified by the wall designer, and clearly shown on the plans. Building walls, below grade, should be water-proofed. Waterproofing should also be provided for site retaining walls in order to reduce the potential for efflorescence staining. Retaining Wall Foundation Design Foundation design for retaining walls should incorporate the following recommendations: Minimum Footing Embedment - 24 inches below the lowest adjacent grade (excluding landscape layer [upper 6 inches]). Minimum Footing Width - 24 inches Allowable Vertical Bearing Pressure - An allowable vertical bearing pressure of 2,500 pcf may be used in the preliminary design of retaining wall foundations provided that the footing maintains a minimum width of 24 inches and extends at least 18 inches into approved engineered fill overlying suitable native soils. This pressure may be increased by one-third for short-term wind and/or seismic loads. Passive Earth Pressure - A passive earth pressure of 275 pcf with a maximum earth pressure of 2,750 psf may be used in the preliminary design of retaining wall foundations provided the foundation is embedded into properly compacted silty to clayey sand fill. Lateral Sliding Resistance - A 0.35 coefficient of friction may be utilized for a concrete to soil contact when multiplied by the dead load. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. Backfill Soil Density - A soil density of 123 to 130 pcf may be used in the design of retaining wall foundations. This assumes an average engineered fill compaction of at least 90 percent of the laboratory standard (ASTM D 1557). Settlement - Provided that the earthwork and foundation recommendations in this report are adhered, foundations bearing on approved non-detrimentally expansive, engineered fill should be minimally designed to accommodate a differential static settlement of 1.5 inches over a 50-foot horizontal span (angular distortion = 1/400). GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 34 Any retaining wall footings near the perimeter of the site, or not within areas of placed compacted fills will likely need to be deepened into relatively dense soils at depth for adequate vertical and lateral bearing support. All retaining wall footing setbacks from slopes should comply with Figure 1808.7.1 of the 2019 CBC. GSI recommends a minimum horizontal setback distance of 7 feet as measured from the bottom, outboard edge of the footing to the 2:1 (h:v) slope face. Restrained Walls Any retaining walls that will be restrained prior to placing and compacting backfill material or that have re-entrant or male corners, should be designed for an at-rest equivalent fluid pressure (EFP) of 55 pcf and 65 pcf for select and very low expansive (E.I. # 50, P.I. < 15) native (onsite) backfill, respectively. The design should include any applicable surcharge loading. For areas of male or re-entrant corners, the restrained wall design should extend a minimum distance of twice the height of the wall (2H) laterally from the corner. Cantilevered Walls The recommendations presented below are for cantilevered retaining walls up to 10 feet high. Design parameters for walls less than 3 feet in height may be superceded by Los Angeles County regional standard design. Active earth pressure may be used for retaining wall design, provided the top of the wall is not restrained from minor deflections. An equivalent fluid pressure approach may be used to compute the horizontal pressure against the wall. Appropriate fluid unit weights are given below for specific slope gradients of the retained material. These do not include other superimposed loading conditions due to traffic, structures, seismic events or adverse geologic conditions. When wall configurations are finalized, the appropriate loading conditions for superimposed loads can be provided upon request. For preliminary planning purposes, the structural consultant/wall designer should incorporate the surcharge of traffic loads on the back of retaining walls where vehicular traffic could occur within horizontal distance “H” from the back of the retaining wall (where “H” equals the wall height). The traffic surcharge may be taken as 100 psf/ft in the upper 5 feet of backfill for light truck and cars traffic. This does not include the surcharge of parked vehicles which should be evaluated at a higher surcharge to account for the effects of seismic loading. Equivalent fluid pressures for the design of cantilevered retaining walls are provided in the following table: GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 35 SURFACE SLOPE OF RETAINED MATERIAL (HORIZONTAL:VERTICAL) EQUIVALENT FLUID WEIGHT P.C.F. (SELECT BACKFILL)(2) EQUIVALENT FLUID WEIGHT P.C.F. (NATIVE BACKFILL)(3) Level(1) 2 to 1 38 55 50 65 Level backfill behind a retaining wall is defined as compacted earth materials, properly drained, without a slope for a distance of 2H behind the wall,(1) where H is the height of the wall. SE > 30, P.I. < 15, E.I. < 21, and < 10% passing No. 200 sieve.(2) E.I. = 0 to 50, SE > 30, P.I. < 15, E.I. < 21, and < 15% passing No. 200 sieve. Assumes 1 to 2 feet of gravel drain backfill be incorporated (see Details(3) herein). Seismic Surcharge For engineered retaining walls with more than 6 feet of retained materials, as measured vertically from the bottom of the wall footing at the heel to daylight , GSI recommends that the walls be evaluated for a seismic surcharge (in general accordance with 2019 CBC requirements). The site walls in this category should maintain an overturning Factor-of-Safety (FOS) of approximately 1.25 when the seismic surcharge (increment), is applied. For restrained walls, the seismic surcharge should be applied as a uniform surcharge load from the bottom of the footing (excluding shear keys) to the top of the backfill at the heel of the wall footing. This seismic surcharge pressure (seismic increment) may be taken as 21H where H for retained walls is the dimension previously noted as the height of the backfill to the bottom of the footing. The resultant force should be applied at a distance 0.6H up from the bottom of the footing. For the evaluation of the seismic surcharge, the bearing pressure may exceed the static value by one-third, considering the transient nature of this surcharge. For cantilevered walls, the pressure should be applied as an inverted triangular distribution using 21H. For restrained walls, the pressure should be applied as a rectangular distribution. Please note this is for local wall stability only. The 21H is derived from a Mononobe-Okabe solution for both restrained cantilever walls. This accounts for the increased lateral pressure due to shakedown or movement of the sand fill soil in the zone of influence from the wall or roughly a 45/ - N/2 plane away from the back of the wall. The 21H seismic surcharge is derived from the formula: hhtP = d C a C (H hWhere:P =Seismic increment ha =Probabilistic horizontal site acceleration with a percentage of “g.” t(=total unit weight (115 to 120 pcf for site soils @ 90% relative compaction). H=Height of the wall from the bottom of the footing or point of pile fixity. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 36 Retaining Wall Backfill and Drainage Positive drainage must be provided behind all retaining walls in the form of gravel wrapped in geofabric and outlets. A backdrain system is considered necessary for retaining walls that are 2 feet or greater in height. Details 1, 2, and 3, present the backdrainage options discussed below. Backdrains should consist of a 4-inch diameter perforated PVC or ABS pipe encased in either Class 2 permeable filter material or ¾-inch to 1½-inch gravel wrapped in approved filter fabric (Mirafi 140 or equivalent). For select backfill, the filter material should extend a minimum of 1 horizontal foot behind the base of the walls and upward at least 1 foot. For native backfill that has up to E.I. = 50 (P.I. < 15), continuous Class 2 permeable drain materials should be used behind the wall. This material should be continuous (i.e., full height) behind the wall, and it should be constructed in accordance with the enclosed Detail 1 (Typical Retaining Wall Backfill and Drainage Detail). For limited access and confined areas, (panel) drainage behind the wall may be constructed in accordance with Detail 2 (Retaining Wall Backfill and Subdrain Detail Geotextile Drain). Materials with an expansion index (E.I.) potential of greater than 50 and/or P.I. > 15 should not be used as backfill for retaining walls. Retaining wall backfill materials should be moisture conditioned and mixed to achieve the soil’s optimum moisture content, placed in relatively thin lifts (6 to 10 inches) with relatively light equipment, and compacted to at least 90 percent relative compaction. For more onerous expansive situations, backfill and drainage behind the retaining wall should conform with Detail 3 (Retaining Wall And Subdrain Detail Clean Sand Backfill). Outlets should consist of a 4-inch diameter solid PVC or ABS pipe spaced no greater than 100 feet apart, with a minimum of two outlets, one on each end. The use of weep holes, only, in walls higher than 2 feet, is not recommended. The surface of the backfill should be sealed by pavement or the top 18 inches compacted with native soil (E.I. # 50 and P.I. < 15). Proper surface drainage should also be provided. For additional mitigation, consideration should be given to applying a water-proof membrane to the back of all retaining structures. The use of a waterstop should be considered for all concrete and masonry joints. Wall/Retaining Wall Footing Transitions Site walls are anticipated to be founded on footings designed in accordance with the recommendations in this report. Should wall footings transition from cut to fill, the structural consultant/wall designer may specify either: a)A minimum of a 2-foot overexcavation and recompaction of cut materials for a distance of 2H, from the point of transition. b)Increase of the amount of reinforcing steel and wall detailing (i.e., expansion joints or crack control joints) such that a angular distortion of 1/360 for a distance of 2H on either side of the transition may be accommodated. Expansion joints should be GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 40 placed no greater than 20 feet on-center, in accordance with the structural engineer’s/wall designer’s recommendations, regardless of whether or not transition conditions exist. Expansion joints should be sealed with a flexible, non-shrink grout. c) Embed the footings entirely into native formational material (i.e., deepened footings). If transitions from cut to fill transect the wall footing alignment at an angle of less than 45 degrees (plan view), then the designer should follow recommendation "a" (above) and until such transition is between 45 and 90 degrees to the wall alignment. Slope Setback Considerations for Footings Footings should maintain a horizontal distance, X, between any adjacent descending slope face and the bottom outer edge of the footing, and minimally comply with the guidelines depicted on Figure 1808.7.1 of the 2019 CBC. The horizontal distance, X, may be calculated by using X = h/3, where h is the height of the slope. X should not be less than 7 feet, nor need not be greater than 40 feet. X may be maintained by deepening the footings. DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS Some of the site soil materials on site may be expansive. The effects of expansive soils are cumulative, and typically occur over the lifetime of any improvements. On relatively level areas, when the soils are allowed to dry, the dessication and swelling process tends to cause heaving and distress to flatwork and other improvements. The resulting potential for distress to improvements may be reduced, but not totally eliminated. To reduce the likelihood of distress, the following recommendations are presented for all exterior flatwork: 1.The subgrade area for exterior concrete slabs should be compacted to achieve a minimum 90 percent relative compaction, and then be presoaked to 2 to 3 percentage points above (or 125 percent of) the soils’ optimum moisture content, to a depth of 18 inches below subgrade elevation. If very low expansive soils are present, only optimum moisture content, or greater, is required and specific presoaking is not warranted. The moisture content of the subgrade should be proof tested within 72 hours prior to pouring concrete. 2.Exterior concrete slabs should be cast over a non-yielding surface, consisting of a 4-inch layer of crushed rock, gravel, or clean sand, that should be compacted and level prior to pouring concrete. If very low expansive soils are present, the rock or gravel or sand may be deleted. The layer or subgrade should be wet-down completely prior to pouring concrete, to minimize loss of concrete moisture to the surrounding earth materials. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 41 3.Exterior slabs should be a minimum of 4 inches thick. Driveway slabs and approaches should additionally have a thickened edge (12 inches) adjacent to all landscape areas, to help impede infiltration of landscape water under the slab. 4.The use of transverse and longitudinal control joints are recommended to help control slab cracking due to concrete shrinkage or expansion. Two ways to mitigate such cracking are: a) add a sufficient amount of reinforcing steel, increasing tensile strength of the slab; and, b) provide an adequate amount of control and/or expansion joints to accommodate anticipated concrete shrinkage and expansion. In order to reduce the potential for unsightly cracks, slabs should be reinforced at mid-height with a minimum of No. 3 bars placed at 18 inches on center, in each direction. If subgrade soils within the top 7 feet from finish grade are very low expansive soils (i.e., E.I. #20), then 6x6-W1.4xW1.4 welded-wire mesh may be substituted for the rebar, provided the reinforcement is placed on chairs, at slab mid-height. The exterior slabs should be scored or saw cut, ½ to d inches deep, often enough so that no section is greater than 10 feet by 10 feet. For sidewalks or narrow slabs, control joints should be provided at intervals of every 6 feet. The slabs should be separated from the foundations and sidewalks with expansion joint filler material. 5.No traffic should be allowed upon the newly poured concrete slabs until they have been properly cured to within 75 percent of design strength. Concrete compression strength should be a minimum of 2,500 psi. 6.Driveways, sidewalks, and patio slabs adjacent to the house should be separated from the house with thick expansion joint filler material. In areas directly adjacent to a continuous source of moisture (i.e., irrigation, planters, etc.), all joints should be additionally sealed with flexible mastic. 7.Planters and walls should not be tied to the house. 8.Overhang structures should be supported on the slabs, or structurally designed with continuous footings tied in at least two directions. If very low expansion soils are present, footings need only be tied in one direction. 9.Any masonry landscape walls that are to be constructed throughout the property should be grouted and articulated in segments no more than 20 feet long. These segments should be keyed or doweled together. 10.Utilities should be enclosed within a closed utilidor (vault) or designed with flexible connections to accommodate differential and expansive soil conditions. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 42 11.Positive site drainage should be maintained at all times. Finish grade on the lots should provide a minimum of 1 to 2 percent fall to the street, as indicated herein. It should be kept in mind that drainage reversals could occur, including post-construction settlement, if relatively flat yard drainage gradients are not periodically maintained by the owner. 12.Air conditioning (A/C) units should be supported by slabs that are incorporated into the building foundation or constructed on a rigid slab with flexible couplings for plumbing and electrical lines. A/C waste water lines should be drained to a suitable non-erosive outlet. 13.Shrinkage cracks could become excessive if proper finishing and curing practices are not followed. Finishing and curing practices should be performed per the Portland Cement Association Guidelines. Mix design should incorporate rate of curing for climate and time of year, sulfate content of soils, corrosion potential of soils, and fertilizers used on site. PRELIMINARY PORTLAND CEMENT CONCRETE PAVEMENT DESIGN RECOMMENDATIONS The preliminary design for Asphaltic Concrete Pavement (ACP) and Portland Cement Concrete Pavement (PCCP) was evaluated based on an subgrade R-value evaluated as R= 80, and the use of concrete shoulders (curb and/or gutter) at the edge of pavement. GSI does not recommend the use of an ADTT value of less than 25 for any pavement section, unless the ADTT significantly less than 25 is certified by a civil engineer specializing in traffic engineering. The preliminary ACP and PCCP sections are provided in the following table: Asphaltic Concrete Pavement (ACP) STREET CLASSIFICATION TRAFFIC INDEX (T.I.)(1) STANDARD PAVEMENT DESIGNS USING CALTRANS CLASS II, OR “GREENBOOK” AGGREGATE BASE (A.B.) R-VALUE A.C. (INCHES)A.B. (INCHES)(2) Parking Areas 4.5 80 3.0 4.0(3) Traffic/Fire Lanes 6.0 80 3.0 6.0(3) Traffic Index Values were assumed based on the intended use.1 Assumed R-values for Class 2 aggregate base R=80 - Base shall conform to Section 400-2.4, in Standard2 Specifications for Public Works Construction, Regional Supplement Amendments. Actual pavement section may be thicker, based on City/County minimums.3 NOTE: Subgrade soils exhibit relatively high R-values, as such, pavement sections will likely default to City and/or County minimum sections. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 43 Portland Concrete Cement Pavement (PCCP) PORTLAND CONCRETE CEMENT PAVEMENTS (PCCP) TRAFFIC AREAS CONCRETE TYPE PCCP THICKNESS (INCHES) TRAFFIC AREAS CONCRETE TYPE PCCP THICKNESS (INCHES) Light Vehicles 520-C-2500 6.5 Heavy Truck Traffic 520-C-2500 8.0 560-C-3250 5.5 560-C-3250 7.0 NOTE: All PCCP is designed as un-reinforced and bearing directly on compacted subgrade. However, a 4-inch thick leveling course of compacted aggregate base, or crushed rock may be considered to improve performance. All PCCP should be properly detailed (jointing, etc.) per the industry standard. Pavements may be additionally reinforced with #4 reinforcing bars, placed 12 inches on center, each way, for improved performance. Trash truck loading pads shall be 8 inches per the City standard reinforced accordingly. The transition of the pavement from parking to traffic lanes should be made over a distance of 24 inches with crack control joints (weaken plane) or contact joints at the end of the transition. A minimum 4-inch layer of base rock in traffic and loading dock areas should be considered to improve traffic lane performance. Base rock may consist of either ¾-inch crushed rock or Caltrans Class 2 aggregate base. Crushed rock may be compacted by vibratory methods. Aggregate base should be compacted to a minimum relative compaction of 95 percent. PCC Pavement Joints Weakened Plane Joints Transverse and longitudinal weakened plane joints may be constructed per Caltrans Standard specifications, Section 40-1.08B and 40-1.08B(1). Transverse weakened plane joints should be spaced no farther than 15 feet apart and no closer than 5 feet. Longitudinal weakened plane joints should be spaced no farther than 20 feet apart, but not less than 5 feet. Expansion Joints Transverse expansion joints should be constructed at 120-foot spacings. Contact Joints Transverse and longitudinal contact joints should be determined by the design engineer. Within large parking areas, joint spacings should be no greater than 20 feet. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 44 Slab Reinforcement PCC Pavements for this project are designed as unreinforced and should perform adequately, assuming proper construction. If additional control of internal slab stresses (i.e., curing shrinkage, thermal expansion and contraction), and the effects of expansive soil subgrades is desired, then the use of No. 3 reinforcing bars, 18 inches on center each way, should be considered. Subgrade should be compacted to a minimum relative compaction of 95 percent. Aggregate base compaction should be 95 percent of the maximum dry density (ASTM D-1557). If adverse conditions (i.e., saturated ground, etc.) are encountered during preparation of subgrade, special construction methods may need to be employed. The recommendations contained herein should be considered preliminary. R-value testing and PPC pavement design analysis should be performed upon completion of grading for the project. Concrete Pavers Concrete pavers should be underlain by a minimum of 8 inches of aggregate base, overlain by a leveling-course of sand. Prior to aggregate base placement the subgrade soils should be compacted to a minimum relative compaction of 95 percent. Aggregate base compaction should also be 95 percent of the maximum dry density (ASTM D-1557), and follow the pavement grading recommendations provided below, as warranted. PAVEMENT GRADING RECOMMENDATIONS General All section changes should be properly transitioned. If adverse conditions are encountered during the preparation of subgrade materials, special construction methods may need to be employed. A GSI representative should be present for the preparation of subgrade, aggregate base, and asphaltic concrete. Subgrade Within drive lanes and parking areas, all surficial deposits of loose soil material should be removed and re-compacted as recommended. After the loose soils are removed, the bottom is to be scarified to a depth of at least 6 inches, moisture conditioned as necessary and compacted to 95 percent of the maximum laboratory density, as determined by ASTM D 1557. Deleterious material, excessively wet or dry pockets, concentrated zones of oversized rock fragments, and any other unsuitable materials encountered during grading should be removed. The compacted fill material should then be brought to the elevation of the GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 45 proposed subgrade for the pavement. The subgrade should be proof-rolled in order to promote a uniform firm and unyielding surface. All grading and fill placement should be observed by the project geotechnical consultant. Aggregate Base Compaction tests are required for the recommended aggregate base section. Minimum relative compaction required will be 95 percent of the laboratory maximum density as determined by ASTM D 1557. Base aggregate should be in accordance to the “Caltrans” crushed aggregate base rock (minimum R-value=78). Drainage Positive drainage should be provided for all surface water to drain towards the area swale, curb and gutter, or to an approved drainage channel. Positive site drainage should be maintained at all times. Water should not be allowed to pond or seep into the ground, such as from behind unprotected curbs, both during and after grading. If planters or landscaping are adjacent to paved areas, measures should be taken to minimize the potential for water to enter the pavement section, such as thickened edges, subdrains, enclosed or lined planters, etc. Also, best management construction practices should be strictly adhered to at all times to minimize the potential for distress during construction and roadway improvements. Additional Considerations To mitigate perched groundwater, consideration should be given to installation of subgrade separators (cut-offs) between pavement subgrade and landscape areas, although this is not a requirement from a geotechnical standpoint. Cut-offs, if used, should be 6 inches wide and at least 12 inches below the pavement subgrade elevation. DEVELOPMENT CRITERIA Slope Maintenance and Planting Water has been shown to weaken the inherent strength of all earth materials. Slope stability is significantly reduced by overly wet conditions. Positive surface drainage away from slopes should be maintained and only the amount of irrigation necessary to sustain plant life should be provided for planted slopes. Over-watering should be avoided as it adversely affects site improvements, and causes perched groundwater conditions. Graded slopes constructed utilizing onsite materials would be erosive. Eroded debris may be minimized and surficial slope stability enhanced by establishing and maintaining a suitable vegetation cover soon after construction. Compaction to the face of fill slopes would tend to minimize short-term erosion until vegetation is established. Plants selected for landscaping should be light weight, deep rooted types that require little water and are GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 46 capable of surviving the prevailing climate. Jute-type matting or other fibrous covers may aid in allowing the establishment of a sparse plant cover. Utilizing plants other than those recommended above will increase the potential for perched water, staining, mold, etc., to develop. A rodent control program to prevent burrowing should be implemented. Irrigation of natural (ungraded) slope areas is generally not recommended. These recommendations regarding plant type, irrigation practices, and rodent control should be provided to each homeowner. Over-steepening of slopes should be avoided during building construction activities and landscaping. Drainage Adequate lot surface drainage is a very important factor in reducing the likelihood of adverse performance of foundations, hardscape, and slopes. Surface drainage should be sufficient to prevent ponding of water anywhere on a lot, and especially near structures and tops of slopes. Lot surface drainage should be carefully taken into consideration during fine grading, landscaping, and building construction. Therefore, care should be taken that future landscaping or construction activities do not create adverse drainage conditions. Positive site drainage within lots and common areas should be provided and maintained at all times. Drainage should not flow uncontrolled down any descending slope. Water should be directed away from foundations and not allowed to pond and/or seep into the ground. In general, the area within 5 feet around a structure should slope away from the structure. We recommend that unpaved lawn and landscape areas have a minimum gradient of 1 percent sloping away from structures, and whenever possible, should be above adjacent paved areas. Consideration should be given to avoiding construction of planters adjacent to structures (buildings, pools, spas, etc.). Pad drainage should be directed toward the street or other approved area(s). Although not a geotechnical requirement, roof gutters, downspouts, or other appropriate, means may be utilized to control roof drainage. Downspouts, or drainage devices, should outlet a minimum of 5 feet from structures or into a subsurface drainage system. Areas of seepage may develop due to irrigation or heavy rainfall, and should be anticipated. Minimizing irrigation will lessen this potential. If areas of seepage develop, recommendations for minimizing this effect could be provided upon request. Erosion Control Cut and fill slopes will be subject to surficial erosion during and after grading. Onsite earth materials have a moderate to high erosion potential. Consideration should be given to providing hay bales and silt fences for the temporary control of surface water, from a geotechnical viewpoint. Landscape Maintenance Only the amount of irrigation necessary to sustain plant life should be provided. Over-watering the landscape areas will adversely affect proposed site improvements. We would recommend that any proposed open-bottom planters adjacent to proposed GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 47 structures be eliminated for a minimum distance of 10 feet. As an alternative, closed-bottom type planters could be utilized. An outlet placed in the bottom of the planter, could be installed to direct drainage away from structures or any exterior concrete flatwork. If planters are constructed adjacent to structures, the sides and bottom of the planter should be provided with a moisture barrier to prevent penetration of irrigation water into the subgrade. Provisions should be made to drain the excess irrigation water from the planters without saturating the subgrade below or adjacent to the planters. Graded slope areas should be planted with drought resistant vegetation. Consideration should be given to the type of vegetation chosen and their potential effect upon surface improvements (i.e., some trees will have an effect on concrete flatwork with their extensive root systems). From a geotechnical standpoint leaching is not recommended for establishing landscaping. If the surface soils are processed for the purpose of adding amendments, they should be recompacted to 90 percent minimum relative compaction. Gutters and Downspouts As previously discussed in the drainage section, the installation of gutters and downspouts should be considered to collect roof water that may otherwise infiltrate the soils adjacent to the structures. If utilized, the downspouts should be drained into PVC collector pipes or other non-erosive devices (e.g., paved swales or ditches; below grade, solid tight-lined PVC pipes; etc.), that will carry the water away from the house, to an appropriate outlet, in accordance with the recommendations of the design civil engineer. Downspouts and gutters are not a requirement; however, from a geotechnical viewpoint, provided that positive drainage is incorporated into project design (as discussed previously). Subsurface and Surface Water Subsurface and surface water are not anticipated to affect site development, provided that the recommendations contained in this report are incorporated into final design and construction and that prudent surface and subsurface drainage practices are incorporated into the construction plans. Perched groundwater conditions along zones of contrasting permeabilities may not be precluded from occurring in the future due to site irrigation, poor drainage conditions, or damaged utilities, and should be anticipated. Should perched groundwater conditions develop, this office could assess the affected area(s) and provide the appropriate recommendations to mitigate the observed groundwater conditions. Groundwater conditions may change with the introduction of irrigation, rainfall, or other factors. Site Improvements If in the future, any additional improvements (e.g., pools, spas, etc.) are planned for the site, recommendations concerning the geological or geotechnical aspects of design and construction of said improvements could be provided upon request. Pools and/or spas should not be constructed without specific design and construction recommendations from GSI, and this construction recommendation should be provided to the homeowners, any GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 48 homeowners association, and/or other interested parties. This office should be notified in advance of any fill placement, grading of the site, or trench backfilling after rough grading has been completed. This includes any grading, utility trench and retaining wall backfills, flatwork, etc. Tile Flooring Tile flooring can crack, reflecting cracks in the concrete slab below the tile, although small cracks in a conventional slab may not be significant. Therefore, the designer should consider additional steel reinforcement for concrete slabs-on-grade where tile will be placed. The tile installer should consider installation methods that reduce possible cracking of the tile such as slipsheets. Slipsheets or a vinyl crack isolation membrane (approved by the Tile Council of America/Ceramic Tile Institute) are recommended between tile and concrete slabs on grade. Additional Grading This office should be notified in advance of any fill placement, supplemental regrading of the site, or trench backfilling after rough grading has been completed. This includes completion of grading in the street, driveway approaches, driveways, parking areas, and utility trench and retaining wall backfills. Footing Trench Excavation All footing excavations should be observed by a representative of this firm subsequent to trenching and prior to concrete form and reinforcement placement. The purpose of the observations is to evaluate that the excavations have been made into the recommended bearing material and to the minimum widths and depths recommended for construction. If loose or compressible materials are exposed within the footing excavation, a deeper footing or removal and recompaction of the subgrade materials would be recommended at that time. Footing trench spoil and any excess soils generated from utility trench excavations should be compacted to a minimum relative compaction of 90 percent, if not removed from the site. Trenching/Temporary Construction Backcuts Considering the nature of the onsite earth materials, it should be anticipated that caving or sloughing could be a factor in subsurface excavations and trenching. Shoring or excavating the trench walls/backcuts at the angle of repose (typically 25 to 45 degrees [except as specifically superceded within the text of this report]), should be anticipated. All excavations should be observed by an engineering geologist or soil engineer from GSI, prior to workers entering the excavation or trench, and minimally conform to CAL-OSHA, state, and local safety codes. Should adverse conditions exist, appropriate recommendations would be offered at that time. The above recommendations should be provided to any contractors and/or subcontractors, or homeowners, etc., that may perform GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 49 such work. Based on the relatively cohesionless and granular nature of gravelly soils onsite, temporary slopes, including utility trenching should consider Type “C” soil conditions per CalOHSA guidelines, on a preliminary basis. Utility Trench Backfill 1.All interior utility trench backfill should be brought to at least 2 percent above optimum moisture content and then compacted to obtain a minimum relative compaction of 90 percent of the laboratory standard. As an alternative for shallow (12-inch to 18-inch) under-slab trenches, sand having a sand equivalent value of 30 or greater may be utilized and jetted or flooded into place. Observation, probing and testing should be provided to evaluate the desired results. 2.Exterior trenches adjacent to, and within areas extending below a 1:1 plane projected from the outside bottom edge of the footing, and all trenches beneath hardscape features and in slopes, should be compacted to at least 90 percent of the laboratory standard. Sand backfill, unless excavated from the trench, should not be used in these backfill areas. Compaction testing and observations, along with probing, should be accomplished to evaluate the desired results. 3.All trench excavations should conform to CAL-OSHA, state, and local safety codes. Type “C” soil conditions per CalOHSA guidelines, should be considered on a preliminary basis. 4.Utilities crossing grade beams, perimeter beams, or footings should either pass below the footing or grade beam utilizing a hardened collar or foam spacer, or pass through the footing or grade beam in accordance with the recommendations of the structural engineer. SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING We recommend that observation and/or testing be performed by GSI at each of the following construction stages: •During grading/recertification. •During excavation. •During placement of subdrains, toe drains, or other subdrainage devices, prior to placing fill and/or backfill. •After excavation of building footings, retaining wall footings, and free standing walls footings, prior to the placement of reinforcing steel or concrete. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 50 •Prior to pouring any slabs or flatwork, after presoaking/presaturation of building pads and other flatwork subgrade, before the placement of concrete, reinforcing steel, capillary break (i.e., sand, pea-gravel, etc.), or vapor barriers (i.e., visqueen, etc.). •During retaining wall subdrain installation, prior to backfill placement. •During placement of backfill for area drain, interior plumbing, utility line trenches, and retaining wall backfill. •During slope construction/repair. •When any unusual soil conditions are encountered during any construction operations, subsequent to the issuance of this report. •When any developer or homeowner improvements, such as flatwork, spas, pools, walls, etc., are constructed, prior to construction. •A report of geotechnical observation and testing should be provided at the conclusion of each of the above stages, in order to provide concise and clear documentation of site work, and/or to comply with code requirements. •GSI should review project sales documents to homeowners/homeowners associations for geotechnical aspects, including irrigation practices, the conditions outlined above, etc., prior to any sales. At that stage, GSI will provide homeowners maintenance guidelines which should be incorporated into such documents. OTHER DESIGN PROFESSIONALS/CONSULTANTS The design civil engineer, structural engineer, post-tension designer, architect, landscape architect, wall designer, etc., should review the recommendations provided herein, incorporate those recommendations into all their respective plans, and by explicit reference, make this report part of their project plans. This report presents minimum design criteria for the design of slabs, foundations and other elements possibly applicable to the project. These criteria should not be considered as substitutes for actual designs by the structural engineer/designer. Please note that the recommendations contained herein are not intended to preclude the transmission of water or vapor through the slab or foundation. The structural engineer/foundation and/or slab designer should provide recommendations to not allow water or vapor to enter into the structure so as to cause damage to another building component, or so as to limit the installation of the type of flooring materials typically used for the particular application. GeoSoils, Inc. Begonia Real Estate Development, Inc.W.O. 8027-A-SC 15926 Foothill Boulevard, Fontana January 21, 2021 File: e:\wp10\murr\sc8000\8027a.pgi Page 51 The structural engineer/designer should analyze actual soil-structure interaction and consider, as needed, bearing, expansive soil influence, and strength, stiffness and deflections in the various slab, foundation, and other elements in order to develop appropriate, design-specific details. As conditions dictate, it is possible that other influences will also have to be considered. The structural engineer/designer should consider all applicable codes and authoritative sources where needed. If analyses by the structural engineer/designer result in less critical details than are provided herein as minimums, the minimums presented herein should be adopted. It is considered likely that some, more restrictive details will be required. If the structural engineer/designer has any questions or requires further assistance, they should not hesitate to call or otherwise transmit their requests to GSI. In order to mitigate potent ial distress, the foundation and/or improvement’s designer should confirm to GSI and the governing agency, in writing, that the proposed foundations and/or improvements can tolerate the amount of differential settlement and/or expansion characteristics and other design criteria specified herein. PLAN REVIEW Final project plans (grading, precise grading, foundation, retaining wall, landscaping, etc.), should be reviewed by this office prior to construction, so that construction is in accordance with the conclusions and recommendations of this report. Based on our review, supplemental recommendations and/or further geotechnical studies may be warranted. LIMITATIONS The materials encountered on the project site and utilized for our analysis are believed representative of the area; however, soil and bedrock materials vary in character between excavations and natural outcrops or conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors. Inasmuch as our study is based upon our review and engineering analyses and laboratory data, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty, either express or implied, is given. Standards of practice are subject to change with time. GSI assumes no responsibility or liability for work or testing performed by others, or their inaction; or work performed when GSI is not requested to be onsite, to evaluate if our recommendations have been properly implemented. Use of this report constitutes an agreement and consent by the user to all the limitations outlined above, notwithstanding any other agreements that may be in place. In addition, this report may be subject to review by the controlling authorities. Thus, this report brings to completion our scope of services for this portion of the project. All samples will be disposed of after 30 days, unless specifically requested by the client, in writing. GeoSoils, Inc. APPENDIX A REFERENCES GeoSoils, Inc. APPENDIX A REFERENCES Allen, V., Connerton, A., and Carlson, C., 2011, Introduction to Infiltration Best Management Practices (BMP), Contech Construction Products, Inc., Professional Development Series, dated December. American Concrete Institute, 2014a, Building code requirements for structural concrete (ACI 318-14), and commentary (ACI 318R-14): reported by ACI Committee 318, dated September. _____, 2014b, Building code requirements for concrete thin shells (ACI 318.2-14), and commentary (ACI 318.2R-14), dated September. _____, 2011, Building code requirements for structural concrete (ACI 318-14), an ACI standard and commentary: reported by ACI Committee 318; dated May 24. _____, 2004, Guide for concrete floor and slab construction: reported by ACI Committee 302; Designation ACI 302.1R-04, dated March 23. American Society of Civil Engineers, 2018a, Supplement 1 to Minimum Design Loads and Associated Criteria for Buildings and Other Structures (ASCE/SEI 7-16), first printing, dated December 13. _____, 2018b, Errata for Minimum Design Loads and Associated Criteria for Buildings and Other Structures (ASCE/SEI 7-16), by ASCE, dated July 9. _____, 2017, Minimum design loads and associated criteria and other structures, ASCE Standard ASCE/SEI 7-16, published online June 19. American Society for Testing and Materials (ASTM), 2005, E 1643-98, Standard practice for installation of water vapor retarders used in contact with earth or granular fill under concrete slabs. Blake, T.F., 2000a, EQFAULT, A computer program for the estimation of peak horizontal acceleration from 3-D fault sources; Windows 95/98 version, updated to September, 2004. _____, 2000b, EQSEARCH, A computer program for the estimation of peak horizontal acceleration from California historical earthquake catalogs; updated through December, 2011, Windows 95/98 version. Bozorgnia, Y., Campbell, K.W., and Niazi, M., 1999, Vertical ground motion: Characteristics, relationship with horizontal component, and building-code implications; Proceedings of the SMIP99 seminar on utilization of strong-motion data, Oakland, pp. 23-49, dated September 15. GeoSoils, Inc.Begonia Real Estate Development, Inc.Appendix A File: e:\wp10\murr\sc8000\8027a.pgi Page 2 Bryant, W.A., and Hart, E.W., 2007, Fault-rupture hazard zones in California, Alquist-Priolo earthquake fault zoning act with index to earthquake fault zones maps; California Geological Survey, Special Publication 42, interim revision. California Building Standards Commission, 2019a, California Building Code, California Code of Regulations, Title 24, Part 2, Volume 2 of 2, based on the 2018 International Building Code, effective January 1, 2020. _____, 2019b, California Building Code, California Code of Regulations, Title 24, Part 2, Volume 1 of 2, Based on the 2018 International Building Code, effective January 1, 2020. California Code Of Regulations, 2011, CAL-OSHA State of California Construction and Safety Orders, dated February. California Department of Conservation, California Geological Survey (CGS), 2018, Earthquake fault zones, a guide for government agencies, property owners/developers, and geoscience practitioners for assessing fault rupture hazards in California: California Geological Survey Special Publication 42 (revised 2018), 93 p. California Department of Conservation, California Geological Survey (CGS), 2008, Guidelines for evaluating and mitigating seismic hazards in California: California Geological Survey Special Publication 117A (revised 2008), 102 p. California Department of Conservation, Division of Mines and Geology (CDMG), 1999, Seismic hazard zones, official map, San Dimas 7.5 minute quadrangle, State of California, SHZR 032, scale: 1:24,000, released March 25. California Department of Conservation, Division of Mines and Geology (CDMG), 1998, Seismic Hazard Report for the San Dimas 7.5 Minute Quadrangle, Los Angeles County, California, SHZR No. 032, text updated 2001. California Department of Water Resources, 2021, Water Data Library, interactive website, http://wdl.water.ca.gov/waterdatalibrary/. California Office of Statewide Health Planning and Development (OSHPD), 2019, Seismic design maps, https://seismicmaps.org/. California Stormwater Quality Association (CASQA), 2003, Stormwater best management practice handbook, new development and redevelopment, dated January. Cao, T., Bryant, W.A., Rowshandel, B., Branum, D., and Wills, C.J., 2003, The revised 2002 California probabilistic seismic hazard maps, dated June, http://www.conservation.ca.gov/cgs/rghm/psha/fault_parameters/pdf/Documents /2002_CA_Hazard_Maps.pdf GeoSoils, Inc.Begonia Real Estate Development, Inc.Appendix A File: e:\wp10\murr\sc8000\8027a.pgi Page 3 Dibblee, T.W., Jr., 2002, Geologic map of the San Dimas and Ontario quadrangles, Los Angeles and San Bernardino Counties, California, Dibblee Geology Center Map #DF-91, Santa Barbara Museum of Natural History. Google Earth Pro - v7.3.2.5776, 2020, by Google, LLC, https://www.google.com/ earth/download/gep/agree.html, [accessed January 10, 2021]. Humphreys & Partners Architects, L.P., 2020, Conceptual site plan, Foothill & Tokay, Fontana, California, 4 sheets, various scales, HPA# 20387, dated December 18. International Code Council, Inc., 2018, International Building Code, Third Printing: September 2019. Jennings, C.W., and Bryant, W.A., 2010, Fault activity map of California, scale 1:750,000, California Geological Survey, Geologic Data Map No. 6. Kanare, Howard, M., 2005, Concrete Floors and Moisture, Engineering Bulletin 119, Portland Cement Association, pp. 35-42. Matlock, H.S. and L.C. Reese, 1960, Generalized solutions for laterally loaded piles, ASCE Journal of Soil Mechanics and Foundation Division, 86 (SM5): pp 63–91. Morton, D.M., and Miller, F.K., 2006, Geologic map of the San Bernardino and Santa Ana 30' x 60' quadrangles, California, geology and description of map units, 1:100,000 scale, United States Geological Survey, Open-File Report 2006-1217 Morton, D.M. 2003, Geologic Map of the Fontana 7.5' quandragle, San Bernardo and Riverside Counties, California, United States Geological Survey, scale 1:24,000, Open-File Report 03-418. Norris, R.M. and Webb, R.W., 1990, Geology of California, Second Edition, John Wiley & Sons, Inc. Post-Tensioning Institute, 2014, Errata to standard requirements for design and analysis of shallow post-tensioned concrete foundations on expansive soils, PTI DC10.5-12, dated April 16. _____, 2013, Errata to standard requirements for design and analysis of shallow post-tensioned concrete foundations on expansive soils, PTI DC10.5-12, dated November 12. _____, 2012, Standard requirements for design and analysis of shallow post-tensioned concrete foundations on expansive soils, PTI DC10.5-12, dated December. San Bernardino County, 2013, Technical guidance document for water quality management plans, Appendix D - Section VII, infiltration rate evaluation protocol and factor of safety recommendations, dated June 7, effective date September 19. GeoSoils, Inc.Begonia Real Estate Development, Inc.Appendix A File: e:\wp10\murr\sc8000\8027a.pgi Page 4 _____, 2010, San Bernardino County land use plan, general plan, geologic hazard overlay, FH29 C, Fontana, 1:14,400 scale, plotted March 9. Seed, R. B., 2005, Evaluation and mitigation of soil liquefaction hazard “evaluation of field data and procedures for evaluating the risk of triggering (or inception) of liquefaction,” in Geotechnical earthquake engineering; short course, San Diego, California, April 8-9. State of California, 2021, Civil Code, Sections 895 et seq. United States Department of Agriculture, 1980, Aerial photographs, project no. 615020, flight date August 10, flight line 180, photos nos. 162 and 163, scale 1"=3333'±. Wire Reinforcement Institute, Inc., 2016, Manual of standard practice, structural welded wire reinforcement, dated December. GeoSoils, Inc. APPENDIX B TEST PIT LOGS UNIFIED SOIL CLASSIFICATION SYSTEM CONSISTENCY OR RELATIVE DENSITY Major Divisions Group Symbols Typical Names CRITERIA Coarse-Grained SoilsMore than 50% retained on No. 200 sieveGravels 50% or more of coarse fraction retained on No. 4 sieveCleanGravelsGW Well-graded gravels and gravel-sand mixtures, little or no fines Standard Penetration Test Penetration Resistance N Relative (blows/ft) Density 0 - 4 Very loose 4 - 10 Loose 10 - 30 Medium 30 - 50 Dense > 50 Very dense GP Poorly graded gravels and gravel-sand mixtures, little or no fines GravelwithGM Silty gravels gravel-sand-silt mixtures GC Clayey gravels, gravel-sand-clay mixtures Sands more than 50% ofcoarse fractionpasses No. 4 sieveCleanSandsSW Well-graded sands and gravelly sands, little or no fines SP Poorly graded sands andgravelly sands, little or no fines SandswithFinesSM Silty sands, sand-silt mixtures SC Clayey sands, sand-clay mixtures Fine-Grained Soils50% or more passes No. 200 sieveSilts and ClaysLiquid limit50% or lessML Inorganic silts, very fine sands,rock flour, silty or clayey finesands Standard Penetration Test Unconfined Penetration Compressive Resistance N Strength (blows/ft) Consistency (tons/ft 2) <2 Very Soft <0.25 2 - 4 Soft 0.25 - .050 4 - 8 Medium 0.50 - 1.00 8 - 15 Stiff 1.00 - 2.00 15 - 30 Very Stiff 2.00 - 4.00 >30 Hard >4.00 CL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays OL Organic silts and organic silty clays of low plasticity Silts and ClaysLiquid limitgreater than 50%MH Inorganic silts, micaceous or diatomaceous fine sands or silts, elastic silts CH Inorganic clays of high plasticity, fat clays OH Organic clays of medium to high plasticity Highly Organic Soils PT Peat, mucic, and other highly organic soils 3" 3/4" #4 #10 #40 #200 U.S. Standard Sieve Unified Soil Classification Cobbles Gravel Sand Silt or Clay coarse fine coarse medium fine MOISTURE CONDITIONS MATERIAL QUANTITY OTHER SYMBOLS Dry Absence of moisture: dusty, dry to the touch trace 0 - 5 % C Core Sample Slightly Moist Below optimum moisture content for compaction few 5 - 10 % S SPT Sample Moist Near optimum moisture content little 10 - 25 % B Bulk Sample Very Moist Above optimum moisture content some 25 - 45 % – Groundwater Wet Visible free water; below water table Qp Pocket Penetrometer BASIC LOG FORMAT: Group name, Group symbol, (grain size), color, moisture, consistency or relative density. Additional comments: odor, presence of roots, mica, gypsum, coarse grained particles, etc. EXAMPLE: Sand (SP), fine to medium grained, brown, moist, loose, trace silt, little fine gravel, few cobbles up to 4" in size, some hair roots and rootlets. File:Mgr: c;\SoilClassif.wpd PLATE B-1 W.O.8027-A-SC Begonia Real Estate Development Foothill Avenue, Fontana Logged By: RGC Date PLATE B-2 LOG OF EXPLORATORY TEST PITS TEST PIT NO. ELEV. (ft.) DEPTH (ft.) GROUP SYMBOL SAMPLE DEPTH (ft.) MOISTURE (%) FIELD DRY DENSITY (pcf) DESCRIPTION 1 1304 0-1½SM COLLUVIUM: SILTY SAND, brown (10YR 4/3), dry, loose; many rootlets, porous. 1½-3 SM ALLUVIUM: SILTY SAND, dark yellowish brown (10YR, 4/4 - 4/6), slightly moist, loose; porous, fine-grained. 3-8 GW GRAVELLY SAND to SANDY GRAVEL, dark yellowish brown (10YR 3/4), slightly moist, medium dense; ±50% well-rounded to subrounded gravel and cobble, some cobbles very brittle. 8-9 GW SANDY GRAVEL, dark brown to dark yellowish brown (10YR 3/3 - 3/4), moist, medium dense; >50% well-rounded gravel and cobble in a well-graded sand matrix. Total Depth = 9' No Groundwater Encountered, Caving of Trench Side Walls Below 3' Excavation Terminated Due to Caving Backfilled 12-9-20 W.O.8027-A-SC Begonia Real Estate Development Foothill Avenue, Fontana Logged By: RGC Date LOG OF EXPLORATORY TEST PITS TEST PIT NO. ELEV. (ft.) DEPTH (ft.) GROUP SYMBOL SAMPLE DEPTH (ft.) MOISTURE (%) FIELD DRY DENSITY (pcf) DESCRIPTION PLATE B-3 2 1304 0-2 SM ½-2 COLLUVIUM: SILTY SAND, dark grayish brown to brown, (10YR 4/2 to 10YR 4/3), dry, loose; porous, many rootlets, fin-grained. 2-2½SM ALLUVIUM: SILTY SAND, brown to yellowish brown (10YR 5/3 to 5/4), slightly moist, loose; porous, very weakly cemented, fine-grained. 2½-8 SM SANDY GRAVEL, yellowish brown (10YR 5/4), slightly moist, loose; 40-60% well-rounded to subrounded gravel and cobble size rock fragments. Sand matrix is well-graded and cohesionless. @4' becomes medium dense. Total Depth = 8' No Groundwater Encountered Sidewall Caving Below 3' Backfilled 12-9-20 W.O.8027-A-SC Begonia Real Estate Development Foothill Avenue, Fontana Logged By: RGC Date LOG OF EXPLORATORY TEST PITS TEST PIT NO. ELEV. (ft.) DEPTH (ft.) GROUP SYMBOL SAMPLE DEPTH (ft.) MOISTURE (%) FIELD DRY DENSITY (pcf) DESCRIPTION PLATE B-4 3 1303 0-½SM COLLUVIUM: SILTY SAND, gray brown to (10YR 5/2 to 5/3), dry, loose; porous, many rootles, 40-50% well-rounded to subrounded gravels. ½-1 GW GRAVELLY SAND with SILT, brown (10YR 5/3), dry, loose; 40-50% well-rounded gravels. 1-4 GW ALLUVIUM: GRAVELLY SAND to SANDY GRAVEL, brown to yellowish brown (10YR 5/3 to 5/4), slightly moist, loose to medium dense; 40-60% well-rounded to subrounded gravels with fine cobble lags along basal contact of fining upward sequences in packages of about 8-12" thick, sub horizontal bedding. 4-8 GW SANDY GRAVEL, dark yellowish brown (10YR 3/4), slightly moist, medium dense; 50-60% well-rounded to subrounded gravels and cobbles, thickly bedded, sand matrix is well-graded and cohesionless. Total Depth = 8' No Groundwater Encountered Some Sidewall Caving Below 4' Backfilled 12-9-20 W.O.8027-A-SC Begonia Real Estate Development Foothill Avenue, Fontana Logged By: RGC Date LOG OF EXPLORATORY TEST PITS TEST PIT NO. ELEV. (ft.) DEPTH (ft.) GROUP SYMBOL SAMPLE DEPTH (ft.) MOISTURE (%) FIELD DRY DENSITY (pcf) DESCRIPTION PLATE B-5 4 1303 0-½SM UNDOCUMENTED FILL: SILTY SAND, very dark grayish brown (10YR 3/2) to dark brown (10YR 3/3), dry, loose; many rootles, abundant gravel and cobble float at surface. ½-4 SW GRAVELLY SILTY SAND, dark brown (10YR 3/3), slightly moist, loose; trace rootlets, 10-20% well-rounded to subangular gravels to fine cobble, some sidewall caving. 4-6 GW ALLUVIUM: GRAVELLY SAND to SANDY GRAVEL, dark yellowish brown (10YR 3/4), slightly moist, medium dense; 40% well-rounded to subrounded gravels and fine to medium cobble, sand matrix is well graded with some silt. Total Depth = 8' No Groundwater Encountered Some Sidewall Caving from 0-4' Backfilled 12-9-20 Note: Embankment Appears to be Old Diversion Dike W.O.8027-A-SC Begonia Real Estate Development Foothill Avenue, Fontana Logged By: RGC Date LOG OF EXPLORATORY TEST PITS TEST PIT NO. ELEV. (ft.) DEPTH (ft.) GROUP SYMBOL SAMPLE DEPTH (ft.) MOISTURE (%) FIELD DRY DENSITY (pcf) DESCRIPTION PLATE B-6 5 1298 0-½SM COLLUVIUM: SILTY SAND, dark brown to brown (10YR 3/3 to 4/3), dry, loose; porous, many rootlets. ½-2½SW/GW GRAVELLY SAND, dark brown (10YR 3/3), dry, loose; 40-50% well- rounded gravels to fine cobbles, local sidewall caving. 2½-8 GW ALLUVIUM: SANDY GRAVEL, dark yellowish brown (10YR 3/4), slightly moist, medium dense; 50%+ well-rounded to subrounded gravel to cobble size rock fragments, cohesionless, fining upward sequences in packages of about 8-12" thick, subhorizontal bedding, local sidewall caving to 8'. Total Depth =8' No Groundwater Encountered Local Sidewall Caving from 0-8' Backfilled 12-9-20 W.O.8027-A-SC Begonia Real Estate Development Foothill Avenue, Fontana Logged By: RGC Date LOG OF EXPLORATORY TEST PITS TEST PIT NO. ELEV. (ft.) DEPTH (ft.) GROUP SYMBOL SAMPLE DEPTH (ft.) MOISTURE (%) FIELD DRY DENSITY (pcf) DESCRIPTION PLATE B-7 6 1298 0-2 SM COLLUVIUM: SILTY SAND, brown (10YR 4/3), dry, loose; porous, few roots in upper 6". 2-3 SM ALLUVIUM: SILTY SAND, dark yellowish brown to brown (10YR 3/4-3/3), slightly moist, loose; porous, fine-grained. 3-8 GW GRAVELLY SAND to SANDY GRAVEL, dark yellowish brown(10YR 3/4), slightly moist, loose to medium dense, ~50%+ well-rounded to subrounded gravel to fine cobbles, well-graded sand matrix. Total Depth = 7' No Groundwater Encountered Some Sidewall Caving Below 3' Backfilled 12-9-20 W.O.8027-A-SC Begonia Real Estate Development Foothill Avenue, Fontana Logged By: RGC Date LOG OF EXPLORATORY TEST PITS TEST PIT NO. ELEV. (ft.) DEPTH (ft.) GROUP SYMBOL SAMPLE DEPTH (ft.) MOISTURE (%) FIELD DRY DENSITY (pcf) DESCRIPTION PLATE B-8 7 1295 0-2 SM COLLUVIUM: SILTY SAND, brown (10YR 4/3), dry, loose; porous, many rootlets in upper 6", bioturbated. 2-8 GW ALLUVIUM: SANDY GRAVEL, dark yellowish brown (10YR 3/4), slightly moist, loose to medium dense, 50% well to subrounded gravels and fine cobbles in a well-graded sand matrix, some caving. @ 4' becomes medium dense, some sidewall caving. Total Depth = 8' No Groundwater Encountered Some Sidewall Caving Between 2-6' Backfilled 12-9-20 8 1295 0-2 SM COLLUVIUM: SILTY SAND, brown to dark grayish brown (10YR 4/2- 4/3), dry, loose; porous, many rootlets in upper ½’, bioturbated throughout. 2-6 GW ALLUVIUM: SANDY GRAVEL, dark yellowish brown (10YR 3/3), slightly moist, loose to medium dense; ±50% well to subrounded gravels and fine cobble in a well-graded sand matrix, fining upward sequences in packages 6-8"" thick. @ 4' Becomes medium dense. Total Depth = 6' No Groundwater Encountered Some Sidewall Caving Between 2' and 5' Backfilled 12-9-20 W.O.8027-A-SC Begonia Real Estate Development Foothill Avenue, Fontana Logged By: RGC Date LOG OF EXPLORATORY TEST PITS TEST PIT NO. ELEV. (ft.) DEPTH (ft.) GROUP SYMBOL SAMPLE DEPTH (ft.) MOISTURE (%) FIELD DRY DENSITY (pcf) DESCRIPTION PLATE B-9 9 1299 0-1 SM COLLUVIUM: SILTY SAND, brown (10YR 4/3), dry, loose; porous, many rootlets. 1-3 SW/GW ALLUVIUM: GRAVELLY SAND, dark brown to brown (10YR 3/3-3/4), slightly moist, loose; 20-20% well-rounded to subrounded gravel clasts, in a well-graded sand matrix. 3-5 GW GRAVELLY SAND to SANDY GRAVEL, dark yellowish brown (10YR 4/4), slightly moist, medium dense; ±50% well-rounded to subrounded gravel to fine cobble size clasts. Total Depth = 5' No Groundwater or Caving Encountered Used for Infiltration Test at 4-5' Backfilled 12-10-20 W.O.8027-A-SC Begonia Real Estate Development Foothill Avenue, Fontana Logged By: RGC Date LOG OF EXPLORATORY TEST PITS TEST PIT NO. ELEV. (ft.) DEPTH (ft.) GROUP SYMBOL SAMPLE DEPTH (ft.) MOISTURE (%) FIELD DRY DENSITY (pcf) DESCRIPTION PLATE B-10 10 1300 0-2½SM UNDOCUMENTED FILL: SILTY SAND, brown, dry, loose; many rootlets in upper 6", burrowed, some angular and well-rounded gravels, construction debris (concrete and rock dump) at surface in vicinity. 2½-4 SM ALLUVIUM: SILTY SAND, brown to yellowish brown (10YR 4/3-5/4), dry, loose, porous; burrowed, few well to subrounded gravels, porous. 4-6 GW GRAVELLY SAND to SANDY GRAVEL, dark yellowish brown (10YR 3/4), slightly moist, medium dense; ±50% well to subrounded gravels to fine cobble, well-graded sand matrix. Total Depth = 6' No Groundwater Encountered Some Minor Sidewall Caving from 2-4' Used for Infiltration Test at 5-6' Backfilled 12-10-20 GeoSoils, Inc. APPENDIX C SEISMICITY DATA TEST.OUT *********************** * * * E Q F A U L T * * * * Version 3.00 * * * *********************** DETERMINISTIC ESTIMATION OF PEAK ACCELERATION FROM DIGITIZED FAULTS JOB NUMBER: 8027-A-SC DATE: 01-14-2021 JOB NAME: BEGONIA FOOTHILL AVE CALCULATION NAME: Test Run Analysis FAULT-DATA-FILE NAME: C:\Program Files\EQFAULT1\CGSFLTE.DAT SITE COORDINATES: SITE LATITUDE: 34.1076 SITE LONGITUDE: 117.4572 SEARCH RADIUS: 62.2 mi ATTENUATION RELATION: 10) Bozorgnia Campbell Niazi (1999) Hor.-Holocene Soil-Cor. UNCERTAINTY (M=Median, S=Sigma): S Number of Sigmas: 1.0 DISTANCE MEASURE: cdist SCOND: 0 Basement Depth: 5.00 km Campbell SSR: 0 Campbell SHR: 0 COMPUTE PEAK HORIZONTAL ACCELERATION FAULT-DATA FILE USED: C:\Program Files\EQFAULT1\CGSFLTE.DAT MINIMUM DEPTH VALUE (km): 3.0 Page 1 W.O. 8027-A-SC PLATE C-1 TEST.OUT --------------- EQFAULT SUMMARY --------------- ----------------------------- DETERMINISTIC SITE PARAMETERS ----------------------------- Page 1 ------------------------------------------------------------------------------- | |ESTIMATED MAX. EARTHQUAKE EVENT | APPROXIMATE |------------------------------- ABBREVIATED | DISTANCE | MAXIMUM | PEAK |EST. SITE FAULT NAME | mi (km) |EARTHQUAKE| SITE |INTENSITY | | MAG.(Mw) | ACCEL. g |MOD.MERC. ================================|==============|==========|==========|========= SAN JACINTO-SAN BERNARDINO | 5.0( 8.0)| 6.7 | 0.566 | X CUCAMONGA | 6.5( 10.4)| 6.9 | 0.739 | XI SAN ANDREAS - San Bernardino M-1| 9.6( 15.4)| 7.5 | 0.529 | X SAN ANDREAS - SB-Coach. M-1b-2 | 9.6( 15.4)| 7.7 | 0.573 | X SAN ANDREAS - Whole M-1a | 9.6( 15.4)| 8.0 | 0.635 | X SAN ANDREAS - SB-Coach. M-2b | 9.6( 15.4)| 7.7 | 0.573 | X SAN ANDREAS - Mojave M-1c-3 | 12.9( 20.8)| 7.4 | 0.408 | X SAN ANDREAS - Cho-Moj M-1b-1 | 12.9( 20.8)| 7.8 | 0.500 | X SAN ANDREAS - 1857 Rupture M-2a | 12.9( 20.8)| 7.8 | 0.500 | X CLEGHORN | 13.0( 21.0)| 6.5 | 0.239 | IX SAN JOSE | 13.8( 22.2)| 6.4 | 0.301 | IX SAN JACINTO-SAN JACINTO VALLEY | 14.4( 23.2)| 6.9 | 0.278 | IX SIERRA MADRE | 15.9( 25.6)| 7.2 | 0.430 | X CHINO-CENTRAL AVE. (Elsinore) | 17.4( 28.0)| 6.7 | 0.289 | IX NORTH FRONTAL FAULT ZONE (West) | 17.7( 28.5)| 7.2 | 0.389 | X WHITTIER | 19.6( 31.6)| 6.8 | 0.194 | VIII ELSINORE (GLEN IVY) | 20.4( 32.8)| 6.8 | 0.187 | VIII PUENTE HILLS BLIND THRUST | 24.5( 39.5)| 7.1 | 0.268 | IX CLAMSHELL-SAWPIT | 25.6( 41.2)| 6.5 | 0.172 | VIII RAYMOND | 30.9( 49.8)| 6.5 | 0.141 | VIII ELSINORE (TEMECULA) | 32.7( 52.7)| 6.8 | 0.115 | VII UPPER ELYSIAN PARK BLIND THRUST | 36.9( 59.4)| 6.4 | 0.111 | VII SAN JOAQUIN HILLS | 37.0( 59.6)| 6.6 | 0.126 | VIII VERDUGO | 37.2( 59.9)| 6.9 | 0.152 | VIII HELENDALE - S. LOCKHARDT | 37.3( 60.0)| 7.3 | 0.142 | VIII NORTH FRONTAL FAULT ZONE (East) | 38.6( 62.2)| 6.7 | 0.128 | VIII SAN JACINTO-ANZA | 40.0( 64.4)| 7.2 | 0.123 | VII PINTO MOUNTAIN | 42.4( 68.2)| 7.2 | 0.116 | VII NEWPORT-INGLEWOOD (L.A.Basin) | 42.8( 68.9)| 7.1 | 0.107 | VII NEWPORT-INGLEWOOD (Offshore) | 44.3( 71.3)| 7.1 | 0.103 | VII HOLLYWOOD | 44.4( 71.4)| 6.4 | 0.091 | VII SAN GABRIEL | 49.3( 79.3)| 7.2 | 0.099 | VII LENWOOD-LOCKHART-OLD WOMAN SPRGS| 49.5( 79.7)| 7.5 | 0.122 | VII SIERRA MADRE (San Fernando) | 49.8( 80.1)| 6.7 | 0.098 | VII PALOS VERDES | 52.6( 84.6)| 7.3 | 0.100 | VII JOHNSON VALLEY (Northern) | 53.1( 85.4)| 6.7 | 0.065 | VI SANTA MONICA | 55.4( 89.1)| 6.6 | 0.082 | VII NORTHRIDGE (E. Oak Ridge) | 55.7( 89.7)| 7.0 | 0.108 | VII ELSINORE (JULIAN) | 56.5( 91.0)| 7.1 | 0.080 | VII LANDERS | 57.9( 93.2)| 7.3 | 0.090 | VII Page 2 W.O. 8027-A-SC PLATE C-2 TEST.OUT ----------------------------- DETERMINISTIC SITE PARAMETERS ----------------------------- Page 2 ------------------------------------------------------------------------------- | |ESTIMATED MAX. EARTHQUAKE EVENT | APPROXIMATE |------------------------------- ABBREVIATED | DISTANCE | MAXIMUM | PEAK |EST. SITE FAULT NAME | mi (km) |EARTHQUAKE| SITE |INTENSITY | | MAG.(Mw) | ACCEL. g |MOD.MERC. ================================|==============|==========|==========|========= SAN ANDREAS - Coachella M-1c-5 | 58.0( 93.3)| 7.2 | 0.084 | VII BURNT MTN. | 59.8( 96.3)| 6.5 | 0.050 | VI EMERSON So. - COPPER MTN. | 60.1( 96.7)| 7.0 | 0.070 | VI EUREKA PEAK | 60.8( 97.9)| 6.4 | 0.046 | VI GRAVEL HILLS - HARPER LAKE | 61.0( 98.2)| 7.1 | 0.074 | VII SANTA SUSANA | 61.5( 98.9)| 6.7 | 0.078 | VII MALIBU COAST | 61.7( 99.3)| 6.7 | 0.078 | VII ******************************************************************************* -END OF SEARCH- 47 FAULTS FOUND WITHIN THE SPECIFIED SEARCH RADIUS. THE SAN JACINTO-SAN BERNARDINO FAULT IS CLOSEST TO THE SITE. IT IS ABOUT 5.0 MILES (8.0 km) AWAY. LARGEST MAXIMUM-EARTHQUAKE SITE ACCELERATION: 0.7388 g Page 3 W.O. 8027-A-SC PLATE C-3 SITE -100 0 100 200 300 400 500 600 700 800 900 1000 1100 -400 -300 -200 -100 0 100 200 300 400 500 600 CALIFORNIA FAULT MAP Begnia Foothill Ave W.O. 8027-A-SC PLATE C-4 .001 .01 .1 1 1 10 100 STRIKE-SLIP FAULTS 10) Bozorgnia Campbell Niazi (1999) Hor.-Holocene Soil-Cor. Acceleration (g)Distance [adist] (km) M=5 M=6 M=7 M=8 W.O. 8027-A-SC PLATE C-5 .001 .01 .1 1 .1 1 10 MAXIMUM EARTHQUAKES Begnia Foothill Ave Acceleration (g)Distance (mi) W.O. 8027-A-SC PLATE C-6 6.50 6.75 7.00 7.25 7.50 7.75 8.00 .1 1 10 EARTHQUAKE MAGNITUDES & DISTANCES Begnia Foothill Ave Magnitude (M)Distance (mi) W.O. 8027-A-SC PLATE C-7 TEST.OUT ************************* * * * E Q S E A R C H * * * * Version 3.00 * * * ************************* ESTIMATION OF PEAK ACCELERATION FROM CALIFORNIA EARTHQUAKE CATALOGS JOB NUMBER: 8027-A-SC DATE: 12-28-2020 JOB NAME: Begnia Foothill Ave EARTHQUAKE-CATALOG-FILE NAME: ALLQUAKE.DAT MAGNITUDE RANGE: MINIMUM MAGNITUDE: 5.00 MAXIMUM MAGNITUDE: 9.00 SITE COORDINATES: SITE LATITUDE: 34.1076 SITE LONGITUDE: 117.4572 SEARCH DATES: START DATE: 1800 END DATE: 2020 SEARCH RADIUS: 62.2 mi 100.1 km ATTENUATION RELATION: 10) Bozorgnia Campbell Niazi (1999) Hor.-Holocene Soil-Cor. UNCERTAINTY (M=Median, S=Sigma): S Number of Sigmas: 1.0 ASSUMED SOURCE TYPE: SS [SS=Strike-slip, DS=Reverse-slip, BT=Blind-thrust] SCOND: 0 Depth Source: A Basement Depth: 5.00 km Campbell SSR: 0 Campbell SHR: 0 COMPUTE PEAK HORIZONTAL ACCELERATION MINIMUM DEPTH VALUE (km): 3.0 Page 1 W.O. 8027-A-SC PLATE C-8 TEST.OUT ------------------------- EARTHQUAKE SEARCH RESULTS ------------------------- Page 1 ------------------------------------------------------------------------------- | | | | TIME | | | SITE |SITE| APPROX. FILE| LAT. | LONG. | DATE | (UTC) |DEPTH|QUAKE| ACC. | MM | DISTANCE CODE| NORTH | WEST | | H M Sec| (km)| MAG.| g |INT.| mi [km] ----+-------+--------+----------+--------+-----+-----+-------+----+------------ DMG |34.2000|117.4000|07/22/1899| 046 0.0| 0.0| 5.50| 0.215 |VIII| 7.2( 11.5) MGI |34.0000|117.5000|12/16/1858|10 0 0.0| 0.0| 7.00| 0.475 | X | 7.8( 12.6) MGI |34.1000|117.3000|07/15/1905|2041 0.0| 0.0| 5.30| 0.157 |VIII| 9.0( 14.5) DMG |34.2700|117.5400|09/12/1970|143053.0| 8.0| 5.40| 0.128 |VIII| 12.2( 19.6) DMG |34.3000|117.5000|07/22/1899|2032 0.0| 0.0| 6.50| 0.230 | IX | 13.5( 21.7) DMG |34.0000|117.2500|07/23/1923| 73026.0| 0.0| 6.25| 0.191 |VIII| 14.0( 22.5) GSP |34.1400|117.7000|02/28/1990|234336.6| 5.0| 5.20| 0.098 | VII| 14.1( 22.6) DMG |34.3000|117.6000|07/30/1894| 512 0.0| 0.0| 6.00| 0.147 |VIII| 15.6( 25.1) DMG |33.9000|117.2000|12/19/1880| 0 0 0.0| 0.0| 6.00| 0.111 | VII| 20.5( 33.1) DMG |34.3700|117.6500|12/08/1812|15 0 0.0| 0.0| 7.00| 0.204 |VIII| 21.2( 34.1) DMG |34.2000|117.1000|09/20/1907| 154 0.0| 0.0| 6.00| 0.106 | VII| 21.4( 34.4) MGI |33.8000|117.6000|04/22/1918|2115 0.0| 0.0| 5.00| 0.054 | VI | 22.8( 36.6) DMG |34.2000|117.9000|08/28/1889| 215 0.0| 0.0| 5.50| 0.063 | VI | 26.1( 42.0) DMG |33.7000|117.4000|04/11/1910| 757 0.0| 0.0| 5.00| 0.043 | VI | 28.3( 45.6) DMG |33.7000|117.4000|05/13/1910| 620 0.0| 0.0| 5.00| 0.043 | VI | 28.3( 45.6) DMG |33.7000|117.4000|05/15/1910|1547 0.0| 0.0| 6.00| 0.079 | VII| 28.3( 45.6) DMG |33.6990|117.5110|05/31/1938| 83455.4| 10.0| 5.50| 0.058 | VI | 28.4( 45.7) DMG |34.2670|116.9670|08/29/1943| 34513.0| 0.0| 5.50| 0.055 | VI | 30.1( 48.4) DMG |34.1800|116.9200|01/16/1930| 02433.9| 0.0| 5.20| 0.044 | VI | 31.1( 50.0) DMG |34.1800|116.9200|01/16/1930| 034 3.6| 0.0| 5.10| 0.042 | VI | 31.1( 50.0) GSP |34.2900|116.9460|02/10/2001|210505.8| 9.0| 5.10| 0.041 | V | 31.8( 51.2) MGI |34.0000|118.0000|12/25/1903|1745 0.0| 0.0| 5.00| 0.038 | V | 31.9( 51.4) GSP |34.2620|118.0020|06/28/1991|144354.5| 11.0| 5.40| 0.047 | VI | 32.9( 52.9) DMG |33.8000|117.0000|12/25/1899|1225 0.0| 0.0| 6.40| 0.086 | VII| 33.7( 54.2) GSP |34.1950|116.8620|08/17/1992|204152.1| 11.0| 5.30| 0.042 | VI | 34.5( 55.6) GSP |34.1630|116.8550|06/28/1992|144321.0| 6.0| 5.30| 0.042 | VI | 34.6( 55.7) GSP |34.3400|116.9000|11/27/1992|160057.5| 1.0| 5.30| 0.041 | V | 35.6( 57.3) PAS |34.0610|118.0790|10/01/1987|144220.0| 9.5| 5.90| 0.059 | VI | 35.7( 57.4) DMG |33.7500|117.0000|06/06/1918|2232 0.0| 0.0| 5.00| 0.034 | V | 36.0( 57.9) DMG |33.7500|117.0000|04/21/1918|223225.0| 0.0| 6.80| 0.104 | VII| 36.0( 57.9) DMG |33.9500|116.8500|09/28/1946| 719 9.0| 0.0| 5.00| 0.034 | V | 36.4( 58.6) GSP |34.2390|116.8370|07/09/1992|014357.6| 0.0| 5.30| 0.040 | V | 36.6( 58.8) GSN |34.2030|116.8270|06/28/1992|150530.7| 5.0| 6.70| 0.096 | VII| 36.6( 58.9) GSP |34.3690|116.8970|12/04/1992|020857.5| 3.0| 5.30| 0.039 | V | 36.7( 59.1) PAS |34.0730|118.0980|10/04/1987|105938.2| 8.2| 5.30| 0.039 | V | 36.7( 59.1) MGI |34.1000|118.1000|07/11/1855| 415 0.0| 0.0| 6.30| 0.073 | VII| 36.7( 59.1) DMG |34.1000|116.8000|10/24/1935|1448 7.6| 0.0| 5.10| 0.034 | V | 37.6( 60.5) DMG |33.7100|116.9250|09/23/1963|144152.6| 16.5| 5.00| 0.030 | V | 41.0( 66.0) DMG |33.9760|116.7210|06/12/1944|104534.7| 10.0| 5.10| 0.030 | V | 43.1( 69.3) DMG |34.1000|116.7000|02/07/1889| 520 0.0| 0.0| 5.30| 0.033 | V | 43.3( 69.7) DMG |33.9940|116.7120|06/12/1944|111636.0| 10.0| 5.30| 0.033 | V | 43.3( 69.7) DMG |33.7500|118.0830|03/13/1933|131828.0| 0.0| 5.30| 0.033 | V | 43.5( 70.0) DMG |33.7500|118.0830|03/11/1933| 910 0.0| 0.0| 5.10| 0.029 | V | 43.5( 70.0) Page 2 W.O. 8027-A-SC PLATE C-9 TEST.OUT DMG |33.7500|118.0830|03/11/1933| 230 0.0| 0.0| 5.10| 0.029 | V | 43.5( 70.0) DMG |33.7500|118.0830|03/11/1933| 323 0.0| 0.0| 5.00| 0.028 | V | 43.5( 70.0) DMG |33.7500|118.0830|03/11/1933| 2 9 0.0| 0.0| 5.00| 0.028 | V | 43.5( 70.0) DMG |33.7830|118.1330|10/02/1933| 91017.6| 0.0| 5.40| 0.034 | V | 44.7( 72.0) DMG |33.6170|117.9670|03/11/1933| 154 7.8| 0.0| 6.30| 0.060 | VI | 44.7( 72.0) DMG |33.7000|118.0670|03/11/1933| 51022.0| 0.0| 5.10| 0.029 | V | 44.9( 72.2) DMG |33.7000|118.0670|03/11/1933| 85457.0| 0.0| 5.10| 0.029 | V | 44.9( 72.2) DMG |33.6830|118.0500|03/11/1933| 658 3.0| 0.0| 5.50| 0.036 | V | 44.9( 72.2) MGI |34.0800|118.2600|07/16/1920|18 8 0.0| 0.0| 5.00| 0.026 | V | 45.9( 73.9) T-A |34.0000|118.2500|01/10/1856| 0 0 0.0| 0.0| 5.00| 0.026 | V | 46.0( 73.9) ------------------------- EARTHQUAKE SEARCH RESULTS ------------------------- Page 2 ------------------------------------------------------------------------------- | | | | TIME | | | SITE |SITE| APPROX. FILE| LAT. | LONG. | DATE | (UTC) |DEPTH|QUAKE| ACC. | MM | DISTANCE CODE| NORTH | WEST | | H M Sec| (km)| MAG.| g |INT.| mi [km] ----+-------+--------+----------+--------+-----+-----+-------+----+------------ T-A |34.0000|118.2500|03/26/1860| 0 0 0.0| 0.0| 5.00| 0.026 | V | 46.0( 73.9) T-A |34.0000|118.2500|09/23/1827| 0 0 0.0| 0.0| 5.00| 0.026 | V | 46.0( 73.9) DMG |33.6170|118.0170|03/14/1933|19 150.0| 0.0| 5.10| 0.027 | V | 46.7( 75.1) DMG |33.5750|117.9830|03/11/1933| 518 4.0| 0.0| 5.20| 0.028 | V | 47.6( 76.5) MGI |34.0000|118.3000|09/03/1905| 540 0.0| 0.0| 5.30| 0.029 | V | 48.8( 78.5) PAS |33.9980|116.6060|07/08/1986| 92044.5| 11.7| 5.60| 0.035 | V | 49.3( 79.3) DMG |33.8500|118.2670|03/11/1933|1425 0.0| 0.0| 5.00| 0.024 | V | 49.7( 79.9) DMG |33.7830|118.2500|11/14/1941| 84136.3| 0.0| 5.40| 0.030 | V | 50.6( 81.5) DMG |34.5190|118.1980|08/23/1952|10 9 7.1| 13.1| 5.00| 0.024 | IV | 50.9( 81.9) DMG |34.0170|116.5000|07/24/1947|221046.0| 0.0| 5.50| 0.029 | V | 55.1( 88.7) DMG |34.0170|116.5000|07/25/1947| 04631.0| 0.0| 5.00| 0.022 | IV | 55.1( 88.7) DMG |34.0170|116.5000|07/25/1947| 61949.0| 0.0| 5.20| 0.024 | V | 55.1( 88.7) DMG |34.0170|116.5000|07/26/1947| 24941.0| 0.0| 5.10| 0.023 | IV | 55.1( 88.7) GSP |34.3410|116.5290|06/28/1992|124053.5| 6.0| 5.20| 0.024 | V | 55.4( 89.1) DMG |34.4110|118.4010|02/09/1971|141028.0| 8.0| 5.30| 0.025 | V | 57.8( 93.0) DMG |34.4110|118.4010|02/09/1971|14 244.0| 8.0| 5.80| 0.033 | V | 57.8( 93.0) DMG |34.4110|118.4010|02/09/1971|14 041.8| 8.4| 6.40| 0.049 | VI | 57.8( 93.0) DMG |34.4110|118.4010|02/09/1971|14 1 8.0| 8.0| 5.80| 0.033 | V | 57.8( 93.0) DMG |34.3080|118.4540|02/09/1971|144346.7| 6.2| 5.20| 0.023 | IV | 58.6( 94.3) GSP |34.1390|116.4310|06/28/1992|123640.6| 10.0| 5.10| 0.022 | IV | 58.7( 94.4) GSN |34.2010|116.4360|06/28/1992|115734.1| 1.0| 7.60| 0.110 | VII| 58.7( 94.5) GSP |34.2310|118.4750|03/20/1994|212012.3| 13.0| 5.30| 0.024 | V | 58.8( 94.6) GSP |34.3320|116.4620|07/01/1992|074029.9| 9.0| 5.40| 0.025 | V | 58.9( 94.8) PAS |34.3270|116.4450|03/15/1979|21 716.5| 2.5| 5.20| 0.022 | IV | 59.7( 96.1) MGI |34.0000|118.5000|11/19/1918|2018 0.0| 0.0| 5.00| 0.020 | IV | 60.1( 96.7) DMG |34.0000|118.5000|08/04/1927|1224 0.0| 0.0| 5.00| 0.020 | IV | 60.1( 96.7) GSP |34.1080|116.4040|06/29/1992|141338.8| 9.0| 5.40| 0.025 | V | 60.2( 96.9) GSP |34.2680|116.4020|06/16/1994|162427.5| 3.0| 5.00| 0.019 | IV | 61.3( 98.6) PAS |34.5160|116.4950|06/01/1975| 13849.2| 4.5| 5.20| 0.022 | IV | 61.7( 99.3) GSP |34.2130|118.5370|01/17/1994|123055.4| 18.0| 6.70| 0.055 | VI | 62.1(100.0) ******************************************************************************* -END OF SEARCH- 83 EARTHQUAKES FOUND WITHIN THE SPECIFIED SEARCH AREA. TIME PERIOD OF SEARCH: 1800 TO 2020 LENGTH OF SEARCH TIME: 221 years THE EARTHQUAKE CLOSEST TO THE SITE IS ABOUT 7.2 MILES (11.5 km) AWAY. Page 3 W.O. 8027-A-SC PLATE C-10 TEST.OUT LARGEST EARTHQUAKE MAGNITUDE FOUND IN THE SEARCH RADIUS: 7.6 LARGEST EARTHQUAKE SITE ACCELERATION FROM THIS SEARCH: 0.475 g COEFFICIENTS FOR GUTENBERG & RICHTER RECURRENCE RELATION: a-value= 1.265 b-value= 0.387 beta-value= 0.891 ------------------------------------ TABLE OF MAGNITUDES AND EXCEEDANCES: ------------------------------------ Earthquake | Number of Times | Cumulative Magnitude | Exceeded | No. / Year -----------+-----------------+------------ 4.0 | 83 | 0.37557 4.5 | 83 | 0.37557 5.0 | 83 | 0.37557 5.5 | 26 | 0.11765 6.0 | 16 | 0.07240 6.5 | 7 | 0.03167 7.0 | 3 | 0.01357 7.5 | 1 | 0.00452 Page 4 W.O. 8027-A-SC PLATE C-11 SITE LEGEND M = 4 M = 5 M = 6 M = 7 M = 8 -100 0 100 200 300 400 500 600 700 800 900 1000 1100 -400 -300 -200 -100 0 100 200 300 400 500 600 EARTHQUAKE EPICENTER MAP Begnia Foothill Ave W.O. 8027-A-SC PLATE C-12 .001 .01 .1 1 1 10 100 STRIKE-SLIP FAULTS 10) Bozorgnia Campbell Niazi (1999) Hor.-Holocene Soil-Cor. Acceleration (g)Distance [adist] (km) M=5 M=6 M=7 M=8 W.O. 8027-A-SC PLATE C-13 .001 .01 .1 1 10 100 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 EARTHQUAKE RECURRENCE CURVE Begnia Foothill Ave Cummulative Number of Events (N)/ YearMagnitude (M) W.O. 8027-A-SC PLATE C-14 2 4 6 8 10 20 40 60 80 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 Number of Earthquakes (N) Above Magnitude (M) Begnia Foothill Ave Cumulative Number of Events (N)Magnitude (M) W.O. 8027-A-SC PLATE C-15 GeoSoils, Inc. APPENDIX D LABORATORY TEST RESULTS Tested By: TR Checked By: TR Client: Begonia Real Estate Project: Foothill, Fontana Source of Sample: B-2 Depth: 0-8 Sample Number: B-2 Proj. No.: 8027-A-SC Date Sampled: Sample Type: Remolded Description: Yellowish Brown Well-Graded Gravel w/Sand & Silt Specific Gravity= 2.65 Remarks: Plate Sample No. Water Content, % Dry Density, pcf Saturation, % Void Ratio Diameter, in. Height, in. Water Content, % Dry Density, pcf Saturation, % Void Ratio Diameter, in. Height, in. Normal Stress, psf Primary Stress, psf Strain, % Residual Stress, psf Strain, % Strain rate, in./min.InitialAt TestShear Stress, psf0 500 1000 1500 2000 2500 3000 Strain, % 0 5 10 15 20 1 2 3Residual Stress, psf Primary Stress, psf 0 1000 2000 3000 Normal Stress, psf 0 1000 2000 3000 4000 5000 6000 C, psf f, deg Tan(f) Primary Residual 31 35.9 0.72 8 34.3 0.68 1 7.8 112.7 44.2 0.4677 2.38 1.00 15.3 113.1 87.4 0.4633 2.38 1.00 550 400 1.3 363 3.3 0.004 2 7.8 112.6 44.0 0.4698 2.38 1.00 15.4 113.1 88.3 0.4624 2.38 1.00 1100 873 2.0 789 4.8 0.004 3 7.8 112.8 44.3 0.4667 2.38 1.00 15.3 113.7 89.0 0.4549 2.38 0.99 2200 1610 3.1 1499 5.9 0.004 D-1 Tested By: TR Checked By: TR 12-28-20 (no specification provided) PL=LL=PI= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= USCS=AASHTO= * Yellowish Brown Well-Graded Gravel w/Silt & Sand 3.5 3 2.52 1.5 1.75 .5 .375#4 #10#20 #40 #60#100 #200 100.0 91.6 83.175.8 68.6 56.851.5 44.5 40.833.6 28.924.5 20.2 15.911.5 6.1 73.8767 66.4047 28.595817.4604 2.5758 0.22440.1245 229.69 1.86 GW-GM Begonia Real Estate Foothill, Fontana 8027-A-SC Soil Description Atterberg Limits Coefficients Classification Remarks Source of Sample: B-2 Depth: 2-8 Sample Number: B-2 Date: Client: Project: Project No:Plate D-2 SIEVE PERCENT SPEC.*PASS? SIZE FINER PERCENT (X=NO)PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 8.4 40.1 17.9 4.7 8.7 14.1 6.16 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report A B C D Compactor air pressure PSI 350 350 350 Water added %2.4 2.8 3.2 Moisture at compaction %10.0 10.4 10.8 Height of sample IN 2.59 2.6 2.61 Dry density PCF 125.5 124.8 123.1 R-Value by exudation 83 80 78 R-Value by exudation, corrected 84 81 79 Exudation pressure PSI 768 356 226 Stability thickness FT 0.22 0.26 0.28 Expansion pressure thickness FT 0.43 0.27 0.20 Traffic index, assumed 5.0 Sample Location: Gravel equivalent factor, assumed 1.25 Sample Description: Expansion, stability equilibrium 0.26 Notes: R-Value by expansion 80 R-Value by exudation 80 Test Method: R-Value at equilibrium 80 GeoSoils, Inc. 5741 Palmer Way Project:Begonia Real Estate Carlsbad, CA 92008 Telephone: (760) 438-3155 Number:8027-A-SC Fax: (760) 931-0915 9/2/2010 Date:January 2021 Plate D-3 TEST SPECIMEN R - VALUE TEST RESULTS - DESIGN CALCULATION DATA 35% Retained on 3/4 inch sieve Yellow Brown Gravel w/Sand & Silt SAMPLE INFORMATION B-2, 0-8ft Cal-Trans Test 301 0.00 0.50 1.00 1.50 2.00 0.00 0.50 1.00 1.50 2.00Cover Thickness by Stability (ft)Cover Thickness by Expansion Pressure (ft) Expansion, Stability Equilibrium 0 10 20 30 40 50 60 70 80 90 100 0100200300400500600700800R-ValueExudation Pressure (psi) R-Value By Exudation Plate D-4 GeoSoils, Inc. APPENDIX E FIELD INFILTRATION TEST DATA Percolation Rate to Infiltration Rate Conversion *∆H r2 60 ∆H 60 r ∆t(r2 + 2rHavg)∆t(r+2Havg) Where: It = tested infiltration rate, inches/hour ∆H = change in head over the time interval, inches ∆t = time interval, minutes r = effective radius of test hole Havg = average head over the time interval, inches ∆t Init Level Fnl Level ∆H Havg It TP-9 7.5 12 2.00 10.00 7.00 19.42 High =19.42 TP-10 4.5 12 2.00 10.00 7.00 32.43 Low = 32.43 Average = 25.92 *Conversion per the "Porchet Method" (RCFC, 2011) W.0.8027-A-SC Plate E-1 Infiltration Test Numbers =Infiltration Rate (It) = TECHNICAL GUIDANCE DOCUMENT APPENDICES VII-35 May 19, 2011 Worksheet H: Factor of Safety and Design Infiltration Rate and Worksheet Factor Category Factor Description Assigned Weight (w) Factor Value (v) Product (p) p = w x v A Suitability Assessment Soil assessment methods 0.25 Predominant soil texture 0.25 Site soil variability 0.25 Depth to groundwater / impervious layer 0.25 Suitability Assessment Safety Factor, SA = p B Design Tributary area size 0.25 Level of pretreatment/ expected sediment loads 0.25 Redundancy 0.25 Compaction during construction 0.25 Design Safety Factor, SB = p Combined Safety Factor, STOT= SA x SB Measured Infiltration Rate, inch/hr, KM (corrected for test-specific bias) Design Infiltration Rate, in/hr, KDESIGN = STOT × KM Supporting Data Briefly describe infiltration test and provide reference to test forms: Note: The minimum combined adjustment factor shall not be less than 2.0 and the maximum combined adjustment factor shall not exceed 9.0. 1 0.25 1 0.25 1 1 0.25 0.25 1.0 2 2 2 2 0.5 0.5 0.5 0.5 2.0 25.92 12.96 Testing per San Bernardino Guidance Document (2011) Factor Category B - Design results shall be confirmed by the design civil 2.0 W.0.8027-A-SC Plate E-2 GeoSoils, Inc. APPENDIX F GENERAL EARTHWORK, GRADING GUIDELINES AND PRELIMINARY CRITERIA GeoSoils, Inc. GENERAL EARTHWORK, GRADING GUIDELINES, AND PRELIMINARY CRITERIA General These guidelines present general procedures and requirements for earthwork and grading as shown on the approved grading plans, including preparation of areas to be filled, placement of fill, installation of subdrains, excavations, and appurtenant structures or flatwork. The recommendations contained in the geotechnical report are part of these earthwork and grading guidelines and would supercede the provisions contained hereafter in the case of conflict. Evaluations performed by the consultant during the course of grading may result in new or revised recommendations which could supercede these guidelines or the recommendations contained in the geotechnical report. Generalized details follow this text. The contractor is responsible for the satisfactory completion of all earthwork in accordance with provisions of the project plans and specifications and latest adopted Code. In the case of conflict, the most onerous provisions shall prevail. The project geotechnical engineer and engineering geologist (geotechnical consultant), and/or their representatives, should provide observation and testing services, and geotechnical consultation during the duration of the project. EARTHWORK OBSERVATIONS AND TESTING Geotechnical Consultant Prior to the commencement of grading, a qualified geotechnical consultant (soil engineer and engineering geologist) should be employed for the purpose of observing earthwork procedures and testing the fills for general conformance with the recommendations of the geotechnical report(s), the approved grading plans, and applicable grading codes and ordinances. The geotechnical consultant should provide testing and observation so that an evaluation may be made that the work is being accomplished as specified. It is the responsibility of the contractor to assist the consultants and keep them apprised of anticipated work schedules and changes, so that they may schedule their personnel accordingly. All remedial removals, clean-outs, prepared ground to receive fill, key excavations, and subdrain installation should be observed and documented by the geotechnical consultant prior to placing any fill. It is the contractor’s responsibility to notify the geotechnical consultant when such areas are ready for observation. Laboratory and Field Tests Maximum dry density tests to determine the degree of compaction should be performed in accordance with American Standard Testing Materials test method ASTM designation D-1557. Random or representative field compaction tests should be performed in GeoSoils, Inc.Begonia Real Estate Development Appendix F File: e:\wp10\murr\sc7900\7924a.pgi Page 2 accordance with test methods ASTM designation D-1556, D-2937 or D-2922, and D-3017, at intervals of approximately ±2 feet of fill height or approximately every 1,000 cubic yards placed. These criteria would vary depending on the soil conditions and the size of the project. The location and frequency of testing would be at the discretion of the geotechnical consultant. Contractor's Responsibility All clearing, site preparation, and earthwork performed on the project should be conducted by the contractor, with observation by a geotechnical consultant, and staged approval by the governing agencies, as applicable. It is the contractor's responsibility to prepare the ground surface to receive the fill, to the satisfaction of the geotechnical consultant, and to place, spread, moisture condition, mix, and compact the fill in accordance with the recommendations of the geotechnical consultant. The contractor should also remove all non-earth material considered unsatisfactory by the geotechnical consultant. Notwithstanding the services provided by the geotechnical consultant, it is the sole responsibility of the contractor to provide adequate equipment and methods to accomplish the earthwork in strict accordance with applicable grading guidelines, latest adopted Code or agency ordinances, geotechnical report(s), and approved grading plans. Sufficient watering apparatus and compaction equipment should be provided by the contractor with due consideration for the fill material, rate of placement, and climatic conditions. If, in the opinion of the geotechnical consultant, unsatisfactory conditions such as questionable weather, excessive oversized rock or deleterious material, insufficient support equipment, etc., are resulting in a quality of work that is not acceptable, the consultant will inform the contractor, and the contractor is expected to rectify the conditions, and if necessary, stop work until conditions are satisfactory. During construction, the contractor shall properly grade all surfaces to maintain good drainage and prevent ponding of water. The contractor shall take remedial measures to control surface water and to prevent erosion of graded areas until such time as permanent drainage and erosion control measures have been installed. SITE PREPARATION All major vegetation, including brush, trees, thick grasses, organic debris, and other deleterious material, should be removed and disposed of off-site. These removals must be concluded prior to placing fill. In-place existing fill, soil, colluvium, colluvium, or rock materials, as evaluated by the geotechnical consultant as being unsuitable, should be removed prior to any fill placement. Depending upon the soil conditions, these materials may be reused as compacted fills. Any materials incorporated as part of the compacted fills should be approved by the geotechnical consultant. Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septic tanks, wells, pipelines, or other structures not located prior to grading, are to be removed GeoSoils, Inc.Begonia Real Estate Development Appendix F File: e:\wp10\murr\sc7900\7924a.pgi Page 3 or treated in a manner recommended by the geotechnical consultant. Soft, dry, spongy, highly fractured, or otherwise unsuitable ground, extending to such a depth that surface processing cannot adequately improve the condition, should be overexcavated down to firm ground and approved by the geotechnical consultant before compaction and filling operations continue. Overexcavated and processed soils, which have been properly mixed and moisture conditioned, should be re-compacted to the minimum relative compaction as specified in these guidelines. Existing ground, which is determined to be satisfactory for support of the fills, should be scarified (ripped) to a minimum depth of 6 to 8 inches, or as directed by the geotechnical consultant. After the scarified ground is brought to optimum moisture content, or greater and mixed, the materials should be compacted as specified herein. If the scarified zone is greater than 6 to 8 inches in depth, it may be necessary to remove the excess and place the material in lifts restricted to about 6 to 8 inches in compacted thickness. Existing ground which is not satisfactory to support compacted fill should be overexcavated as required in the geotechnical report, or by the on-site geotechnical consultant. Scarification, disc harrowing, or other acceptable forms of mixing should continue until the soils are broken down and free of large lumps or clods, until the working surface is reasonably uniform and free from ruts, hollows, hummocks, mounds, or other uneven features, which would inhibit compaction as described previously. Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical [h:v]), the ground should be stepped or benched. The lowest bench, which will act as a key, should be a minimum of 15 feet wide and should be at least 2 feet deep into firm material, and approved by the geotechnical consultant. In fill-over-cut slope conditions, the recommended minimum width of the lowest bench or key is also 15 feet, with the key founded on firm material, as designated by the geotechnical consultant. As a general rule, unless specifically recommended otherwise by the geotechnical consultant, the minimum width of fill keys should be equal to ½ the height of the slope. Standard benching is generally 4 feet (minimum) vertically, exposing firm, acceptable material. Benching may be used to remove unsuitable materials, although it is understood that the vertical height of the bench may exceed 4 feet. Pre-stripping may be considered for unsuitable materials in excess of 4 feet in thickness. All areas to receive fill, including processed areas, removal areas, and the toes of fill benches, should be observed and approved by the geotechnical consultant prior to placement of fill. Fills may then be properly placed and compacted until design grades (elevations) are attained. COMPACTED FILLS Any earth materials imported or excavated on the property may be utilized in the fill provided that each material has been evaluated to be suitable by the geotechnical GeoSoils, Inc.Begonia Real Estate Development Appendix F File: e:\wp10\murr\sc7900\7924a.pgi Page 4 consultant. These materials should be free of roots, tree branches, other organic matter, or other deleterious materials. All unsuitable materials should be removed from the fill as directed by the geotechnical consultant. Soils of poor gradation, undesirable expansion potential, or substandard strength characteristics may be designated by the consultant as unsuitable and may require blending with other soils to serve as a satisfactory fill material. Fill materials derived from benching operations should be dispersed throughout the fill area and blended with other approved material. Benching operations should not result in the benched material being placed only within a single equipment width away from the fill/bedrock contact. Oversized materials defined as rock, or other irreducible materials, with a maximum dimension greater than 12 inches, should not be buried or placed in fills unless the location of materials and disposal methods are specifically approved by the geotechnical consultant. Oversized material should be taken offsite, or placed in accordance with recommendations of the geotechnical consultant in areas designated as suitable for rock disposal. GSI anticipates that soils to be utilized as fill material for the subject project may contain some rock. Appropriately, the need for rock disposal may be necessary during grading operations on the site. From a geotechnical standpoint, the depth of any rocks, rock fills, or rock blankets, should be a sufficient distance from finish grade. This depth is generally the same as any overexcavation due to cut-fill transitions in hard rock areas, and generally facilitates the excavation of structural footings and substructures. Should deeper excavations be proposed (i.e., deepened footings, utility trenching, swimming pools, spas, etc.), the developer may consider increasing the hold-down depth of any rocky fills to be placed, as appropriate. In addition, some agencies/jurisdictions mandate a specific hold-down depth for oversize materials placed in fills. The hold-down depth, and potential to encounter oversize rock, both within fills, and occurring in cut or natural areas, would need to be disclosed to all interested/affected parties. Once approved by the governing agency, the hold-down depth for oversized rock (i.e., greater than 12 inches) in fills on this project is provided as 10 feet, unless specified differently in the text of this report. The governing agency may require that these materials need to be deeper, crushed, or reduced to less than 12 inches in maximum dimension, at their discretion. To facilitate future trenching, rock (or oversized material), should not be placed within the hold-down depth feet from finish grade, the range of foundation excavations, future utilities, or underground construction unless specifically approved by the governing agency, the geotechnical consultant, and/or the developer’s representative. If import material is required for grading, representative samples of the materials to be utilized as compacted fill should be analyzed in the laboratory by the geotechnical consultant to evaluate it’s physical properties and suitability for use onsite. Such testing should be performed three (3) days prior to importation. If any material other than that previously tested is encountered during grading, an appropriate analysis of this material should be conducted by the geotechnical consultant as soon as possible. GeoSoils, Inc.Begonia Real Estate Development Appendix F File: e:\wp10\murr\sc7900\7924a.pgi Page 5 Approved fill material should be placed in areas prepared to receive fill in near horizontal layers, that when compacted, should not exceed about 6 to 8 inches in thickness. The geotechnical consultant may approve thick lifts if testing indicates the grading procedures are such that adequate compaction is being achieved with lifts of greater thickness. Each layer should be spread evenly and blended to attain uniformity of material and moisture suitable for compaction. Fill layers at a moisture content less than optimum should be watered and mixed, and wet fill layers should be aerated by scarification, or should be blended with drier material. Moisture conditioning, blending, and mixing of the fill layer should continue until the fill materials have a uniform moisture content at, or above, optimum moisture. After each layer has been evenly spread, moisture conditioned, and mixed, it should be uniformly compacted to a minimum of 90 percent of the maximum density as evaluated by ASTM test designation D-1557, or as otherwise recommended by the geotechnical consultant. Compaction equipment should be adequately sized and should be specifically designed for soil compaction, or of proven reliability to efficiently achieve the specified degree of compaction. Where tests indicate that the density of any layer of fill, or portion thereof, is below the required relative compaction, or improper moisture is in evidence, the particular layer or portion shall be re-worked until the required density and/or moisture content has been attained. No additional fill shall be placed in an area until the last placed lift of fill has been tested and found to meet the density and moisture requirements, and is approved by the geotechnical consultant. In general, per the latest adopted Code, fill slopes should be designed and constructed at a gradient of 2:1 (h:v), or flatter. Compaction of slopes should be accomplished by over- building a minimum of 3 feet horizontally, and subsequently trimming back to the design slope configuration. Testing shall be performed as the fill is elevated to evaluate compaction as the fill core is being developed. Special efforts may be necessary to attain the specified compaction in the fill slope zone. Final slope shaping should be performed by trimming and removing loose materials with appropriate equipment. A final evaluation of fill slope compaction should be based on observation and/or testing of the finished slope face. Where compacted fill slopes are designed steeper than 2:1 (h:v), prior approval from the governing agency, specific material types, a higher minimum relative compaction, special reinforcement, and special grading procedures will be recommended. If an alternative to over-building and cutting back the compacted fill slopes is selected, then special effort should be made to achieve the required compaction in the outer 10 feet of each lift of fill by undertaking the following: 1.An extra piece of equipment consisting of a heavy, short-shanked sheepsfoot should be used to roll (horizontal) parallel to the slopes continuously as fill is placed. The sheepsfoot roller should also be used to roll perpendicular to the GeoSoils, Inc.Begonia Real Estate Development Appendix F File: e:\wp10\murr\sc7900\7924a.pgi Page 6 slopes, and extend out over the slope to provide adequate compaction to the face of the slope. 2.Loose fill should not be spilled out over the face of the slope as each lift is compacted. Any loose fill spilled over a previously completed slope face should be trimmed off or be subject to re-rolling. 3.Field compaction tests will be made in the outer (horizontal) ±2 to ±8 feet of the slope at appropriate vertical intervals, subsequent to compaction operations. 4.After completion of the slope, the slope face should be shaped with a small tractor and then re-rolled with a sheepsfoot to achieve compaction to near the slope face. Subsequent to testing to evaluate compaction, the slopes should be grid-rolled to achieve compaction to the slope face. Final testing should be used to evaluate compaction after grid rolling. 5.Where testing indicates less than adequate compaction, the contractor will be responsible to rip, water, mix, and recompact the slope material as necessary to achieve compaction. Additional testing should be performed to evaluate compaction. SUBDRAIN INSTALLATION Subdrains should be installed in approved ground in accordance with the approximate alignment and details indicated by the geotechnical consultant. Subdrain locations or materials should not be changed or modified without approval of the geotechnical consultant. The geotechnical consultant may recommend and direct changes in subdrain line, grade, and drain material in the field, pending exposed conditions. The location of constructed subdrains, especially the outlets, should be recorded/surveyed by the project civil engineer. Drainage at the subdrain outlets should be provided by the project civil engineer. EXCAVATIONS Excavations and cut slopes should be examined during grading by the geotechnical consultant. If directed by the geotechnical consultant, further excavations or overexcavation and refilling of cut areas should be performed, and/or remedial grading of cut slopes should be performed. When fill-over-cut slopes are to be graded, unless otherwise approved, the cut portion of the slope should be observed by the geotechnical consultant prior to placement of materials for construction of the fill portion of the slope. The geotechnical consultant should observe all cut slopes, and should be notified by the contractor when excavation of cut slopes commence. If, during the course of grading, unforeseen adverse or potentially adverse geologic GeoSoils, Inc.Begonia Real Estate Development Appendix F File: e:\wp10\murr\sc7900\7924a.pgi Page 7 conditions are encountered, the geotechnical consultant should investigate, evaluate, and make appropriate recommendations for mitigation of these conditions. The need for cut slope buttressing or stabilizing should be based on in-grading evaluation by the geotechnical consultant, whether anticipated or not. Unless otherwise specified in geotechnical and geological report(s), no cut slopes should be excavated higher or steeper than that allowed by the ordinances of controlling governmental agencies. Additionally, short-term stability of temporary cut slopes is the contractor’s responsibility. Erosion control and drainage devices should be designed by the project civil engineer and should be constructed in compliance with the ordinances of the controlling governmental agencies, and/or in accordance with the recommendations of the geotechnical consultant. COMPLETION Observation, testing, and consultation by the geotechnical consultant should be conducted during the grading operations in order to state an opinion that all cut and fill areas are graded in accordance with the approved project specifications. After completion of grading, and after the geotechnical consultant has finished observations of the work, final reports should be submitted, and may be subject to review by the controlling governmental agencies. No further excavation or filling should be undertaken without prior notification of the geotechnical consultant or approved plans. All finished cut and fill slopes should be protected from erosion and/or be planted in accordance with the project specifications and/or as recommended by a landscape architect. Such protection and/or planning should be undertaken as soon as practical after completion of grading. PRELIMINARY OUTDOOR POOL/SPA DESIGN RECOMMENDATIONS The following preliminary recommendations are provided for consideration in pool/spa design and planning. Actual recommendations should be provided by a qualified geotechnical consultant, based on site specific geotechnical conditions, including a subsurface investigation, differential settlement potential, expansive and corrosive soil potential, proximity of the proposed pool/spa to any slopes with regard to slope creep and lateral fill extension, as well as slope setbacks per Code, and geometry of the proposed improvements. Recommendations for pools/spas and/or deck flatwork underlain by expansive soils, or for areas with differential settlement greater than ¼-inch over 40 feet horizontally, will be more onerous than the preliminary recommendations presented below. The 1:1 (h:v) influence zone of any nearby retaining wall site structures should be delineated on the project civil drawings with the pool/spa. This 1:1 (h:v) zone is defined as a plane up from the lower-most heel of the retaining structure, to the daylight grade of GeoSoils, Inc.Begonia Real Estate Development Appendix F File: e:\wp10\murr\sc7900\7924a.pgi Page 8 the nearby building pad or slope. If pools/spas or associated pool/spa improvements are constructed within this zone, they should be re-positioned (horizontally or vertically) so that they are supported by earth materials that are outside or below this 1:1 plane. If this is not possible given the area of the building pad, the owner should consider eliminating these improvements or allow for increased potential for lateral/vertical deformations and associated distress that may render these improvements unusable in the future, unless they are periodically repaired and maintained. The conditions and recommendations presented herein should be disclosed to all homeowners and any interested/affected parties. General 1.The equivalent fluid pressure to be used for the pool/spa design should be 60 pounds per cubic foot (pcf) for pool/spa walls with level backfill, and 75 pcf for a 2:1 sloped backfill condition. In addition, backdrains should be provided behind pool/spa walls subjacent to slopes. 2.Passive earth pressure may be computed as an equivalent fluid having a density of 150 pcf, to a maximum lateral earth pressure of 1,000 pounds per square foot (psf). 3.An allowable coefficient of friction between soil and concrete of 0.30 may be used with the dead load forces. 4.When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. 5.Where pools/spas are planned near structures, appropriate surcharge loads need to be incorporated into design and construction by the pool/spa designer. This includes, but is not limited to landscape berms, decorative walls, footings, built-in barbeques, utility poles, etc. 6.All pool/spa walls should be designed as “free standing” and be capable of supporting the water in the pool/spa without soil support. The shape of pool/spa in cross section and plan view may affect the performance of the pool, from a geotechnical standpoint. Pools and spas should also be designed in accordance with the latest adopted Code. Minimally, the bottoms of the pools/spas, should maintain a distance H/3, where H is the height of the slope (in feet), from the slope face. This distance should not be less than 7 feet, nor need not be greater than 40 feet. 7.The soil beneath the pool/spa bottom should be uniformly moist with the same stiffness throughout. If a fill/cut transition occurs beneath the pool/spa bottom, the cut portion should be overexcavated to a minimum depth of 48 inches, and replaced with compacted fill, such that there is a uniform blanket that is a minimum of 48 inches below the pool/spa shell. If very low expansive soil is used for fill, the GeoSoils, Inc.Begonia Real Estate Development Appendix F File: e:\wp10\murr\sc7900\7924a.pgi Page 9 fill should be placed at a minimum of 95 percent relative compaction, at optimum moisture conditions. This requirement should be 90 percent relative compaction at over optimum moisture if the pool/spa is constructed within or near expansive soils. The potential for grading and/or re-grading of the pool/spa bottom, and attendant potential for shoring and/or slot excavation, needs to be considered during all aspects of pool/spa planning, design, and construction. 8.If the pool/spa is founded entirely in compacted fill placed during rough grading, the deepest portion of the pool/spa should correspond with the thickest fill on the lot. 9.Hydrostatic pressure relief valves should be incorporated into the pool and spa designs. A pool/spa under-drain system is also recommended, with an appropriate outlet for discharge. 10.All fittings and pipe joints, particularly fittings in the side of the pool or spa, should be properly sealed to prevent water from leaking into the adjacent soils materials, and be fitted with slip or expandible joints between connections transecting varying soil conditions. 11.An elastic expansion joint (flexible waterproof sealant) should be installed to prevent water from seeping into the soil at all deck joints. 12.A reinforced grade beam should be placed around skimmer inlets to provide support and mitigate cracking around the skimmer face. 13.In order to reduce unsightly cracking, deck slabs should minimally be 4 inches thick, and reinforced with No. 3 reinforcing bars at 18 inches on-center. All slab reinforcement should be supported to ensure proper mid-slab positioning during the placement of concrete. Wire mesh reinforcing is specifically not recommended. Deck slabs should not be tied to the pool/spa structure. Pre-moistening and/or pre-soaking of the slab subgrade is recommended, to a depth of 12 inches (optimum moisture content), or 18 inches (120 percent of the soil’s optimum moisture content, or 3 percent over optimum moisture content, whichever is greater), for very low to low, and medium expansive soils, respectively. This moisture content should be maintained in the subgrade soils during concrete placement to promote uniform curing of the concrete and minimize the development of unsightly shrinkage cracks. Slab underlayment should consist of a 1- to 2-inch leveling course of sand (S.E.>30) and a minimum of 4 to 6 inches of Class 2 base compacted to 90 percent. Deck slabs within the H/3 zone, where H is the height of the slope (in feet), will have an increased potential for distress relative to other areas outside of the H/3 zone. If distress is undesirable, improvements, deck slabs or flatwork should not be constructed closer than H/3 or 7 feet (whichever is greater) from the slope face, in order to reduce, but not eliminate, this potential. GeoSoils, Inc.Begonia Real Estate Development Appendix F File: e:\wp10\murr\sc7900\7924a.pgi Page 10 14.Pool/spa bottom or deck slabs should be founded entirely on competent bedrock, or properly compacted fill. Fill should be compacted to achieve a minimum 90 percent relative compaction, as discussed above. Prior to pouring concrete, subgrade soils below the pool/spa decking should be throughly watered to achieve a moisture content that is at least 2 percent above optimum moisture content, to a depth of at least 18 inches below the bottom of slabs. This moisture content should be maintained in the subgrade soils during concrete placement to promote uniform curing of the concrete and minimize the development of unsightly shrinkage cracks. 15.In order to reduce unsightly cracking, the outer edges of pool/spa decking to be bordered by landscaping, and the edges immediately adjacent to the pool/spa, should be underlain by an 8-inch wide concrete cutoff shoulder (thickened edge) extending to a depth of at least 12 inches below the bottoms of the slabs to mitigate excessive infiltration of water under the pool/spa deck. These thickened edges should be reinforced with two No. 4 bars, one at the top and one at the bottom. Deck slabs may be minimally reinforced with No. 3 reinforcing bars placed at 18 inches on-center, in both directions. All slab reinforcement should be supported on chairs to ensure proper mid-slab positioning during the placement of concrete. 16.Surface and shrinkage cracking of the finish slab may be reduced if a low slump and water-cement ratio are maintained during concrete placement. Concrete utilized should have a minimum compressive strength of 4,000 psi. Excessive water added to concrete prior to placement is likely to cause shrinkage cracking, and should be avoided. Some concrete shrinkage cracking, however, is unavoidable. 17.Joint and sawcut locations for the pool/spa deck should be determined by the design engineer and/or contractor. However, spacings should not exceed 6 feet on center. 18.Considering the nature of the onsite earth materials, it should be anticipated that caving or sloughing could be a factor in subsurface excavations and trenching. Shoring or excavating the trench walls/backcuts at the angle of repose (typically 25 to 45 degrees), should be anticipated. All excavations should be observed by a representative of the geotechnical consultant, including the project geologist and/or geotechnical engineer, prior to workers entering the excavation or trench, and minimally conform to Cal/OSHA (“Type C” soils may be assumed), state, and local safety codes. Should adverse conditions exist, appropriate recommendations should be offered at that time by the geotechnical consultant. GSI does not consult in the area of safety engineering and the safety of the construction crew is the responsibility of the pool/spa builder. 19.It is imperative that adequate provisions for surface drainage are incorporated by the homeowners into their overall improvement scheme. Ponding water, ground saturation and flow over slope faces, are all situations which must be avoided to enhance long term performance of the pool/spa and associated improvements, and reduce the likelihood of distress. GeoSoils, Inc.Begonia Real Estate Development Appendix F File: e:\wp10\murr\sc7900\7924a.pgi Page 11 20.Regardless of the methods employed, once the pool/spa is filled with water, should it be emptied, there exists some potential that if emptied, significant distress may occur. Accordingly, once filled, the pool/spa should not be emptied unless evaluated by the geotechnical consultant and the pool/spa builder. 21.For pools/spas built within (all or part) of the Code setback and/or geotechnical setback, as indicated in the site geotechnical documents, special foundations are recommended to mitigate the affects of creep, lateral fill extension, expansive soils and settlement on the proposed pool/spa. Most municipalities or County reviewers do not consider these effects in pool/spa plan approvals. As such, where pools/spas are proposed on 20 feet or more of fill, medium or highly expansive soils, or rock fill with limited “cap soils” and built within Code setbacks, or within the influence of the creep zone, or lateral fill extension, the following should be considered during design and construction: OPTION A: Shallow foundations with or without overexcavation of the pool/spa “shell,” such that the pool/spa is surrounded by 5 feet of very low to low expansive soils (without irreducible particles greater that 6 inches), and the pool/spa walls closer to the slope(s) are designed to be free standing. GSI recommends a pool/spa under-drain or blanket system (see attached Typical Pool/Spa Detail). The pool/spa builders and owner in this optional construction technique should be generally satisfied with pool/spa performance under this scenario; however, some settlement, tilting, cracking, and leakage of the pool/spa is likely over the life of the project. OPTION B: Pier supported pool/spa foundations with or without overexcavation of the pool/spa shell such that the pool/spa is surrounded by 5 feet of very low to low expansive soils (without irreducible particles greater than 6 inches), and the pool/spa walls closer to the slope(s) are designed to be free standing. The need for a pool/spa under-drain system may be installed for leak detection purposes. Piers that support the pool/spa should be a minimum of 12 inches in diameter and at a spacing to provide vertical and lateral support of the pool/spa, in accordance with the pool/spa designers recommendations current applicable Codes. The pool/spa builder and owner in this second scenario construction technique should be more satisfied with pool/spa performance. This construction will reduce settlement and creep effects on the pool/spa; however, it will not eliminate these potentials, nor make the pool/spa “leak-free.” 22.The temperature of the water lines for spas and pools may affect the corrosion properties of site soils, thus, a corrosion specialist should be retained to review all spa and pool plans, and provide mitigative recommendations, as warranted. Concrete mix design should be reviewed by a qualified corrosion consultant and materials engineer. GeoSoils, Inc.Begonia Real Estate Development Appendix F File: e:\wp10\murr\sc7900\7924a.pgi Page 12 23.All pool/spa utility trenches should be compacted to 90 percent of the laboratory standard, under the full-time observation and testing of a qualified geotechnical consultant. Utility trench bottoms should be sloped away from the primary structure on the property (typically the residence). 24.Pool and spa utility lines should not cross the primary structure’s utility lines (i.e., not stacked, or sharing of trenches, etc.). 25.The pool/spa or associated utilities should not intercept, interrupt, or otherwise adversely impact any area drain, roof drain, or other drainage conveyances. If it is necessary to modify, move, or disrupt existing area drains, subdrains, or tightlines, then the design civil engineer should be consulted, and mitigative measures provided. Such measures should be further reviewed and approved by the geotechnical consultant, prior to proceeding with any further construction. 26.The geotechnical consultant should review and approve all aspects of pool/spa and flatwork design prior to construction. A design civil engineer should review all aspects of such design, including drainage and setback conditions. Prior to acceptance of the pool/spa construction, the project builder, geotechnical consultant and civil designer should evaluate the performance of the area drains and other site drainage pipes, following pool/spa construction. 27.All aspects of construction should be reviewed and approved by the geotechnical consultant, including during excavation, prior to the placement of any additional fill, prior to the placement of any reinforcement or pouring of any concrete. 28.Any changes in design or location of the pool/spa should be reviewed and approved by the geotechnical and design civil engineer prior to construction. Field adjustments should not be allowed until written approval of the proposed field changes are obtained from the geotechnical and design civil engineer. 29.Disclosure should be made to homeowners and builders, contractors, and any interested/affected parties, that pools/spas built within about 15 feet of the top of a slope, and/or H/3, where H is the height of the slope (in feet), will experience some movement or tilting. While the pool/spa shell or coping may not necessarily crack, the levelness of the pool/spa will likely tilt toward the slope, and may not be esthetically pleasing. The same is true with decking, flatwork and other improvements in this zone. 30.Failure to adhere to the above recommendations will significantly increase the potential for distress to the pool/spa, flatwork, etc. 31.Local seismicity and/or the design earthquake will cause some distress to the pool/spa and decking or flatwork, possibly including total functional and economic loss. GeoSoils, Inc.Begonia Real Estate Development Appendix F File: e:\wp10\murr\sc7900\7924a.pgi Page 13 32.The information and recommendations discussed above should be provided to any contractors and/or subcontractors, or homeowners, interested/affected parties, etc., that may perform or may be affected by such work. JOB SAFETY General At GSI, getting the job done safely is of primary concern. The following is the company's safety considerations for use by all employees on multi-employer construction sites. On-ground personnel are at highest risk of injury, and possible fatality, on grading and construction projects. GSI recognizes that construction activities will vary on each site, and that site safety is the prime responsibility of the contractor; however, everyone must be safety conscious and responsible at all times. To achieve our goal of avoiding accidents, cooperation between the client, the contractor, and GSI personnel must be maintained. In an effort to minimize risks associated with geotechnical testing and observation, the following precautions are to be implemented for the safety of field personnel on grading and construction projects: Safety Meetings: GSI field personnel are directed to attend contractor’s regularly scheduled and documented safety meetings. Safety Vests: Safety vests are provided for, and are to be worn by GSI personnel, at all times, when they are working in the field. Safety Flags:Two safety flags are provided to GSI field technicians; one is to be affixed to the vehicle when on site, the other is to be placed atop the spoil pile on all test pits. Flashing Lights:All vehicles stationary in the grading area shall use rotating or flashing amber beacons, or strobe lights, on the vehicle during all field testing. While operating a vehicle in the grading area, the emergency flasher on the vehicle shall be activated. In the event that the contractor's representative observes any of our personnel not following the above, we request that it be brought to the attention of our office. Test Pits Location, Orientation, and Clearance The technician is responsible for selecting test pit locations. A primary concern should be the technician’s safety. Efforts will be made to coordinate locations with the grading contractor’s authorized representative, and to select locations following or behind the established traffic pattern, preferably outside of current traffic. The contractor’s authorized representative (supervisor, grade checker, dump man, operator, etc.) should direct GeoSoils, Inc.Begonia Real Estate Development Appendix F File: e:\wp10\murr\sc7900\7924a.pgi Page 14 excavation of the pit and safety during the test period. Of paramount concern should be the soil technician’s safety, and obtaining enough tests to represent the fill. Test pits should be excavated so that the spoil pile is placed away from oncoming traffic, whenever possible. The technician's vehicle is to be placed next to the test pit, opposite the spoil pile. This necessitates the fill be maintained in a driveable condition. Alternatively, the contractor may wish to park a piece of equipment in front of the test holes, particularly in small fill areas or those with limited access. A zone of non-encroachment should be established for all test pits. No grading equipment should enter this zone during the testing procedure. The zone should extend approximately 50 feet outward from the center of the test pit. This zone is established for safety and to avoid excessive ground vibration, which typically decreases test results. When taking slope tests, the technician should park the vehicle directly above or below the test location. If this is not possible, a prominent flag should be placed at the top of the slope. The contractor's representative should effectively keep all equipment at a safe operational distance (e.g., 50 feet) away from the slope during this testing. The technician is directed to withdraw from the active portion of the fill as soon as possible following testing. The technician's vehicle should be parked at the perimeter of the fill in a highly visible location, well away from the equipment traffic pattern. The contractor should inform our personnel of all changes to haul roads, cut and fill areas or other factors that may affect site access and site safety. In the event that the technician’s safety is jeopardized or compromised as a result of the contractor’s failure to comply with any of the above, the technician is required, by company policy, to immediately withdraw and notify his/her supervisor. The grading contractor’s representative will be contacted in an effort to affect a solution. However, in the interim, no further testing will be performed until the situation is rectified. Any fill placed can be considered unacceptable and subject to reprocessing, recompaction, or removal. In the event that the soil technician does not comply with the above or other established safety guidelines, we request that the contractor bring this to the technician’s attention and notify this office. Effective communication and coordination between the contractor’s representative and the soil technician is strongly encouraged in order to implement the above safety plan. Trench and Vertical Excavation It is the contractor's responsibility to provide safe access into trenches where compaction testing is needed. Our personnel are directed not to enter any excavation or vertical cut which: 1) is 5 feet or deeper unless shored or laid back; 2) displays any evidence of instability, has any loose rock or other debris which could fall into the trench; or 3) displays any other evidence of any unsafe conditions regardless of depth. GeoSoils, Inc.Begonia Real Estate Development Appendix F File: e:\wp10\murr\sc7900\7924a.pgi Page 15 All trench excavations or vertical cuts in excess of 5 feet deep, which any person enters, should be shored or laid back. Trench access should be provided in accordance with Cal/OSHA and/or state and local standards. Our personnel are directed not to enter any trench by being lowered or “riding down” on the equipment. If the contractor fails to provide safe access to trenches for compaction testing, our company policy requires that the soil technician withdraw and notify his/her supervisor. The contractor’s representative will be contacted in an effort to affect a solution. All backfill not tested due to safety concerns or other reasons could be subject to reprocessing and/or removal. If GSI personnel become aware of anyone working beneath an unsafe trench wall or vertical excavation, we have a legal obligation to put the contractor and owner/developer on notice to immediately correct the situation. If corrective steps are not taken, GSI then has an obligation to notify Cal/OSHA and/or the proper controlling authorities. ALL LOCATIONS ARE APPROXIMATE This document or efile is not a part of the Construction Documents and should not be relied upon as being an accurate depiction of design. W.O.DATE:SCALE:8027-A-SC 01/21 1" = 100' Plate 1 GEOTECHNICAL MAP GSI LEGEND Afu Qyfl BASE MAP FROM: TP-8 TP-9 TP-10 TP-7TP-8 TP-6 TP-5 TP-4 TP-1 TP-2 TP-3 Afu Afu Afu Afu Qyfl Qyfl Qyfl Qyfl Qyfl Qyfl N TP-10