Loading...
HomeMy WebLinkAboutTract Map 36483 SIP Soils ReportGEOTECHNICAL UPDATE REPORT FOR TENTATIVE TRACT 36483 (PASEO DEL SOL PROJECT) 42.6-ACRE SITE, NWC OF TEMECULA PARKWAY AND BUTTERFIELD STAGE ROAD, CITY OF TEMECULA RIVERSIDE COUNTY, CALIFORNIA APNS 959-400-001 AND 959-400-002 FOR WOODSIDE 05S, LP 1250 CORONA POINTE COURT, SUITE 500 CORONA, CALIFORNIA 92879 W.O. 8577-A-SC APRIL 7, 2023 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 April 7, 2023 W.O. 8577-A-SC Woodside 05S, LP 1250 Corona Pointe Court, Suite 500 Corona, California 92879 Attention:Mr. Michael Jagels Subject:Geotechnical Update Report for Tentative Tract 36483 (Paseo del Sol Project), 42.6-Acre Site, NWC of Temecula Parkway and Butterfield Stage Road, City of Temecula, Riverside County, California, APNs 959-400-001 and 959-400-002 Dear Mr. Jagels: In accordance with your request and authorization, GeoSoils, Inc. (GSI) is pleased to present our geotechnical update report for Tentative Tract 36483 in the City of Temecula, Riverside County, California. The scope of our services has included a review of the previous geotechnical investigation and update geotechnical investigation reports for the tentative tract by Converse Consultants (CC, 2015 and 2012), review of the tentative tract map by Michael Baker International (MBI, 2022), a review evaluation of updated foundation and seismic design parameters in general accordance with current Code requirements (2022 CBC), review of onsite geologic conditions, analysis of data, and preparation of this geotechnical update report and accompaniments. SITE LOCATION AND BACKGROUND Tentative Tract 36483 is located at the NWC of Temecula Parkway and Butterfield Stage Road in the City of Temecula, Riverside County, California (see Figure 1, Site Location Map). Based on our review, the site is currently vacant and largely undeveloped, except for previous episodes of rough grading activities onsite, between 1996 and 2002. A Rancho California Water District facility is located in the southern central portion of the property. Tentative Tract 36483 has been previously graded under the geotechnical observation and testing services of Converse Consultants (CC, 1997). The geotechnical report of rough grading (CC, 1997) was not currently available for our review; however, the tract has remained largely undeveloped since initial site grading activities. In 2012, CC prepared a geotechnical investigation report for the 43-acre project site, which anticipated a commercial and multi-family development concept. The initial geotechnical investigation by CC (2012) included the advancement of 12 exploratory borings onsite for geotechnical SITE Base Map: Google Maps, Copyright 2023, Map Data Copyright 2023 Google NOT TO SCALE SITE LOCATION MAP Figure 1 W.O. 8577-A-SC This Map is copyrighted by Google 2023. It is unlawful to copy or reproduce all or any part thereof, whether for personal use of resale, without permission. All rights reserved. Base Map: TOPO! Copyright 2003 National Geographic, USGS Pechenga Quadrangle, California -- Riverside Co., 7.5 Minute, dated 1968, Photorevised 1988. SITE GeoSoils, Inc. logging and sampling, as well as discussions on the potential for subsidence and analyses for liquefaction. CC (2012) concluded that some relatively thin layers of the alluvial sediments underlying the project site were susceptible to liquefaction (i.e., BH-1 @ 45-51.5 feet and BH-11 @ 20-25 feet). Dynamic settlement of these layers was estimated at 0.52 and 0.80 inches, respectively, for BH-1 and BH-11. The initial geotechnical investigation by CC (2012) also provided seismic and foundation recommendations under the purview of the 2010 CBC. As described by CC (2012), the site currently contains three (3) superpads, at two (2) elevations. The northern portion of the site contains two (2) of the superpads, generally separated by a drainage area, which accommodates/accepts drainage from the developed residential parcels to the north; the southern portion of the site contains one (1) of the described superpads (CC, 2012). During site grading activities, up to approximately 15 to 35 feet of compacted fill was placed to create the two (2) northern superpads (CC, 2012). The lower (southern) superpad is near pre-graded elevations, and may contain up to 15 feet of compacted fill (CC, 2012). The earthen berms on the lower portions of the site are constructed of compacted fills (CC, 2012). After the initial geotechnical investigation by CC (2012), an update geotechnical investigation report was prepared by CC in 2015. The update geotechnical report by CC (2015) was prepared for a single-family development concept, and included seismic and foundation recommendations under the purview of the 2013 CBC. The reader is referred to the initial geotechnical investigation report by CC (2012) and update geotechnical report by CC (2015) for additional information related to site grading and the initial site study. For convenience the Boring Logs for the initial site study by CC (2012) are presented in Appendix B. It is also our understanding that MDS Consulting has been retained by the developer to update the tract map for submittal to the City. Pending updates to the tract map will likely include 40-scale development plans, as well as other required 2022 CBC code updates. Based on the above, geotechnical recommendations for preparing the site for single-family residential development have been appropriately updated herein in general accordance with current Code requirements (2022 CBC). The updated foundation and seismic shaking design parameters, and site grading recommendations included herein may be applied to the proposed residential development and associated improvements, as required by the City of Temecula, to satisfy City requirements for an update geotechnical report for the project site. SITE CONDITIONS Topographically, the proposed development consists of previously graded elevated terrain to the north, separated by an existing drainage course, and generally flat-lying previously graded terrain to the south. Site elevations generally vary from approximately 1,147 feet MSL (Mean Sea Level) at the northwestern edge of the site to approximately 1,091 feet Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 3 GeoSoils, Inc. MSL near the southwest corner of the property. Therefore, overall relief in the areas proposed for residential development is on the order of 56 feet. Based on the site grading conducted (CC, 1997), and geologic mapping by Kennedy (2000), a majority of the site is underlain by compacted fills, in turn underlain by late Holocene-age active alluvial flood plain deposits (Qa), in the northeastern and southern portions of the project, and early Pleistocene-age sedimentary bedrock assigned to the Pauba Formation (Qp) in the northwestern portion of the site. These materials are locally mantled by undocumented artificial fill (Afu). A review of background information indicates that the site is not located within an Alquist-Priolo Earthquake Fault Zone (California Department of Conservation, California Geological Survey [CGS], 2018), nor is it located within a County of Riverside fault zone. However, based on our review of the Riverside County Information Technology website (RCIT, 2023), the site is located within a zone of “very high” to “moderate” liquefaction potential, and is characterized as being potentially susceptible to subsidence (RCIT, 2023), absent mitigation. PROPOSED DEVELOPMENT AND PLAN REVIEW Based on our review of the updated 60-scale tentative tract map prepared by MBI (2022), GSI understands that the proposed development would include preparing the site for new residential construction consisting of 168 single-family residences, several open space areas and water quality basins, associated infrastructure and underground utility improvements, perimeter block wall and localized retaining wall improvements. Planned cuts and fills are on the order of approximately 16 and 20 feet, respectively. Cut slopes are proposed to be constructed at gradients of 2:1 horizontal to vertical (h:v), or flatter, up to about 19 feet in vertical height, while fill slopes are proposed to be constructed at gradients of 2:1 (h:v), or flatter, up to about 10 feet in vertical height. We further understand that the residential buildings are proposed as one- or two-story structures, with slab-on-grade/continuous footings, using typical wood-frame and stucco type construction. Building loads are assumed to be typical for this type of relatively light structures. Sewage disposal is to be accommodated by tying into the regional system. SITE GEOLOGIC UNITS The geologic units observed, or previously encountered onsite by CC (20212), consist of; undocumented artificial fill, compacted artificial fill, active alluvial flood plain deposits, and sedimentary bedrock assigned to the Pleistocene-age Pauba Formation. The approximate limits of the mappable units are presented on Figure 2 (Geotechnical Map). These units are described, from youngest to oldest, as follows: Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 4 SCALE: See Scale DATE: 04/23 W.O. 8577-A-SC ALL LOCATIONS ARE APPROXIMATE This document or e-file is not part of the Construction Documents and should not be relied upon as being an accurate depiction of design. GEOTECHNICAL MAP Figure 2 GSI LEGEND B-6 B-4 B-2 B-3 B-5 B-1 Qp Afc B-8 B-7 B-12 B-10 B-11 B-9 Afc Qa Afc Qa Afc Qa Afc Qa Afu Afu ? Approximate Boundary of Property Under the Purview of this Report. Approximate Location of Concealed Geologic Contact, Queried where Uncertain. Artificial Fill, Compacted. Afc Artificial Fill - Undocumented, Localized Stockpiles and Berms. Afu Approximate Location of Exploratory Boring by Converse Consultants (2012). B-12 Approximate Location of Geologic Contact. Qa Quaternary Young Alluvium, Circled Where Buried. Quaternary Pauba Formation, Circled Where Buried. Qp Approximate Location of Existing Drainage Area, Holding Ponds, and Potentially Wet/Saturated Materials. Existing Holding Pond Existing Holding Pond NAP Not A Part of this Study. NAP NAP NAP NAP NAP NAP NAP Figure Adapted from the 60-Scale Tentative Tract Map No. 36483, by Michael Baker International (2022). NAP GeoSoils, Inc. Artificial Fill - Undocumented (Map Symbol - Afu) Localized undocumented artificial fill was observed during our site geologic mapping which generally included localized soils/rock stockpiles and earthen berms. The undocumented fill is typically loose, and locally contains moderate to locally abundant amounts of trash and debris. The undocumented fill is deemed unsuitable for the support of new structures or additional fill placement, and will require removal and recompaction during rough grading. Undocumented fill materials may be reused for compacted fills, provided that they have been cleaned of deleterious materials (i.e., trash, debris, oversized rock and concrete) and approved by the geotechnical consultant prior to placement onsite as engineered fill. Artificial Fill - Compacted (Map Symbol - Afc) As discussed previously, the site has been previously rough graded; compacted artificial fill was observed throughout a majority of the project site. The compacted fill materials ranged in composition but were generally medium brown, silty to clayey sands. As described by CC (2012), the thickness of the previously placed compacted fills generally ranges between approximately 15 to 35 feet, on the two (2) upper superpads, while the lower superpad is near original pre-graded elevations, and may contain up to 15 feet of compacted fill. The compacted fill materials are anticipated to have a very low to low expansion potential based on previous site work by CC (2012). The near-surface compacted fill materials are eroded and weathered in their existing state, and therefore, the upper approximately 3 feet should be removed and recompacted during grading improvements, if not removed by planned cuts. Wet to saturated earth materials should be anticipated, and will likely be encountered within the observed existing/active and constructed drainage course transecting the site, and within the holding pond areas (see Figure 2). Any organic-rich soils (exceeding 2 percent) encountered within the existing drainage course and the holding pond areas should be removed from the site, or used in non-structural landscape areas. If not removed from the site, the landscape architect should review and approve the use of any organic-rich soils. Late Holocene-age Active Alluvial Flood Plain Deposits (Map Symbol - Qa) Late Holocene-age active alluvial flood plain deposits (Qa) were documented underlying the compacted fills throughout a majority of the site (CC, 2012). The previous reports by CC (2012 and 2015) described these materials as Holocene alluvial deposits. Based on the thickness of the existing compacted fills (approximately 15 to 35 feet), these earth materials are not anticipated to be encountered during a majority of site grading activities. However, the active alluvial flood plain deposits may be locally exposed around portions of the perimeter of site, or within the existing/active drainage course transecting the site, depending on previous grading boundary areas, and perimeter/confining conditions encountered during original site grading activities. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 6 GeoSoils, Inc. Bedrock - Quaternary-age Pauba Formation (Map Symbol - Qp) Sedimentary bedrock deposits assigned to the Pleistocene-age (Quaternary) Pauba Formation are mapped (Kennedy, 2000) and described by CC (2012 and 2015) underlying the compacted artificial fill in the northwest portions of the project site. The Pauba Formation in the site area consists of very light to grayish brown to reddish brown, silty and clayey fine- to coarse-grained sandstones with minor interbedded clayey and sandy siltstones, and occasional discontinuous layers or lenses of cobble to boulder-sized clasts. The sedimentary bedrock varied from damp to wet, and is generally medium dense to dense with depth. The Pauba Formation is gently inclined to the north, and favorable for site development. Due to the potential for settlement, the near surface weathered bedrock materials (approximately the upper 1 foot), should also be removed prior to compacted fill placement. For convenience, the approximate locations of the site geologic units, geologic contacts, and previous exploratory borings advanced onsite by CC (2012) are presented on Figure 2 (Geotechnical Map). GROUNDWATER Seeps, springs, or mottled soils were not noted at the subject site during our review or during the previous investigation by CC (2012). However, indications of a high (relatively shallow) regional groundwater level were noted during our review. As indicated by CC (2012) groundwater was encountered only in BH-11 at a depth of approximately 39.5 feet below the ground surface (bgs). Based on our review of the California Department of Water Resources Water Data Library (CDWR; 2023), historic well measurements reviewed appear to be regional groundwater measurements at depths of 14 and 32.4 feet (Well No. 08S02W15D001S, and State Well No. 334798N1171015W001, respectively) at sites with similar ground surface elevations. In addition, saturated soils and standing/running water were observed within the existing/active drainage course transecting the site, likely due to recent heavy rain events. 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, site drainage indicates a seasonal flow of runoff enters near the northern portion of the site. As such, it may be anticipated that local/seasonal perched groundwater occurs near the contact between surficial soils and dense sedimentary bedrock, or alluvial deposits at depth. As such, perched water and seepage may be anticipated within the existing/active drainage course transecting the site, along fill/bedrock contacts, or along bedrock discontinuities (fractures or bedding plans) due to migration from adjacent drainage areas and development during or after periods of above normal or heavy precipitation or irrigation. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 7 GeoSoils, Inc. FAULTING AND REGIONAL SEISMICITY Local Faulting The site is situated in an area of active as well as potentially-active faults. The nearby Temecula segment of the Elsinore fault zone is considered active and is included within an Alquist-Priolo Earthquake Fault Zone. Our review of published data indicates that there are no known active faults crossing the site, and the site is not within a Earthquake Fault Zone (CGS, 2018). During our review of aerial photographs (USDA, 1980), we did not observe any photolineaments transecting the site. However, the main trace of the Elsinore fault is located approximately 3.4 miles (5.4 kilometers) to the southwest (Blake, 2000) and should have the greatest effect on the site in the form of strong ground shaking, should the design earthquake occur. The possibility of ground acceleration, or shaking at the site, may be considered as approximately similar to the southern California region as a whole. Updated Seismic Shaking Parameters The following table summarizes the reevaluated site-specific design criteria obtained from the 2022 CBC, Chapter 16 Structural Design, Section 1613, Earthquake Loads. The computer program Seismic Design Maps, provided by the California Office of Statewide Health Planning and Development (OSHPD, 2023) has now been used to aid in design (https://seismicmaps.org). The short spectral response uses a period of 0.2 seconds. 2022 C BC SEISMIC DESIGN PARAM ETERS PARAM ETER SIM PL IFIED VA LUE*202 2 C BC or REFEREN CE Risk Category I, II, III Table 1604.5 Site Class D Section 1613.2.2/Chap. 20 ASCE 7-16 (p. 203-204) Spectral Response - (0.2 sec), Ss 1.543 g Section 1613.2.1 Figure 1613.2.1 Spectral Response - (1 sec), S1 0.572 g Section 1613.2.1 Figure 1613.2.1 Site Coefficient, Fa 1.4 Table 1613.2.3 5% Damped Design Spectral Response Acceleration (0.2 sec), SDS = 2/3 (Fa)(Ss)1.440 ASCE 7-16 (Eqn 12.14-12) PGAM - Probabilistic Vertical Ground PGAM=(FPG A)(PGA)= (1.1)(0.687g) Vertical acceleration may be assumed as about 50% of these values. 0.756 g ASCE 7-16 (Eqn 11.8.1) Seismic Design Category D Section 1613.2.5/ASCE 7-16 (p. 85: Table 11.6-1 or 11.6-2) * Site Class D, and all of the resulting parameters in this table may only be used for structures without seismic isolation or seismic damping systems, less than three stories in height. Risk Category to be confirmed by the Project Architect or Structural Engineer. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 8 GeoSoils, Inc. GENERAL SEISMIC PARAMETERS PARAMETER VALUE Distance to Seismic Source (A fault)(1)3.4 mi/5.4 km(2) Upper Bound Earthquake (Temecula - Elsinore)MW = 6.8(1) (1) - Cao, et al. (2003) (2) - Blake (2000) Conformance to the criteria above for seismic design does not constitute any kind of guarantee or assurance that significant structural damage, ground failure, or surface manifestations will not occur in the event of a large earthquake in this region. 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 2022 CBC (CBSC, 2022) and regular maintenance and repair following locally significant seismic events (i.e., Mw 5.5) will likely be necessary. 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. PREVIOUS LABORATORY TESTING Laboratory Standard The maximum density and optimum moisture content was previously determined for the major soil types encountered (CC, 2012) in general accordance with the laboratory standard ASTM D 1557. The moisture-density relationships previously obtained for the onsite soils are shown below: LOCATION AND DEPTH (FT) DESCRIPTION MAXIMUM DENSITY (PCF) OPTIMUM MOISTURE CONTENT (%) BH-1 @ 0-5'Silty SAND (SM), Brown 133.5 7.0 BH-8 @ 5-10'Clayey SAND (SC), Dark Brown 125.5 8.5 BH-11 @ 10-15'Silty SAND (SM), Brown 122.1 4.5 Expansion Potential Expansion index (E.I.) testing was previously performed (CC, 2012) on representative samples of site earth materials in general accordance with ASTM D 4829. Test results Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 9 GeoSoils, Inc. indicate that the surficial site soils are very low to low in expansion potential (E.I. from 0 to 50). Additional E.I. testing should be conducted at the conclusion of site grading to further evaluate the preliminary test results obtained. The test result and classification are presented in the following table: LOCATION AND DEPTH (FT)EXPANSION INDEX CLASSIFICATION BH-4 @ 5-10'18 Very Low BH-8 @ 5-10'33 Low* *Indicates Plasticity Index (PI) may be over 15. Direct Shear Testing Direct shear testing was previously performed (CC, 2012) on representative samples obtained during the initial site investigation. The samples were sheared under varying confining loads in order to determine the Coulomb shear strength parameters, angle of internal friction and cohesion. The shear testing results previously obtained (CC, 2012) are presented in the following table: LOCATION AND DEPTH (FT) PEAK VALUES C (psf)M (degrees) BH-3 @ 5-6.5'100 30 BH-7 @ 5-6.5'150 31 BH-10 @ 10-11.5'100 30 Resistance Value Resistance value, or R-Value testing, was previously performed (CC, 2012) on representative soil samples in general accordance with ASTM D 2844, and yielded test results ranging from R=17 to R=52. The results of R-Value testing previously conducted (CC, 2012) are presented in the following table: LOCATION AND DEPTH (FT)R-VALUE BH-1 @ 0-5'17 BH-5 @ 0-5'18 BH-9 @ 0-5'52 Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 10 GeoSoils, Inc. Soluble Sulfate/Corrosion Testing Typical samples of the site materials were previously analyzed for soluble sulfates, pH, and resistivity (CC, 2012). Additional sulfate/corrosion testing should be conducted at the conclusion of site grading to further evaluate the preliminary test results obtained. The preliminary soluble sulfate and corrosion potential results are shown as follows: LOCATION AND DEPTH (FT) SOLUBLE SULFATES PERCENTAGE BY WEIGHT pH SATURATED RESISTIVITY (OHMS-CM) BH-5 @ 0-5'0.026 8.0 2,964 BH-9 @ 0-5'0.0299 8.3 1,500 For preliminary planning and design purposes, and based upon the soluble sulfate test results and the American Concrete Institute (ACI, 2014a), the soluble sulfate content for the subject building pad is classified as “S0” (< 0.10 Water-Soluble Sulfate in soil, percentage by mass). As such, Type V concrete with a modified compressive strength is not currently anticipated based on the preliminary testing results obtained. Based on the results of the resistivity and pH testing, the onsite soils are generally moderately alkaline (a pH of 7.9 to 8.4 is considered moderately alkaline), and are considered corrosive to moderately corrosive to ferrous metals in a saturated state (1,000 to 2,000 ohm-cm is considered corrosive, 2,000 to 10,000 ohm-cm is considered moderately corrosive). Although the site soils are categorized as being corrosive to moderately corrosive toward ferrous metals, it is our understanding that ferrous metals embedded in properly poured and formed concrete with the proper mix should be adequately protected from these conditions. As stated above, the soluble sulfate content is classified as “S0,” and other than Exposure Classes S0, C1, and W1, no exposure conditions indicated in Table 19.3.1.1 of the ACI (2014a), were considered warranted, based on our preliminary laboratory testing. Additional sulfate/corrosion testing should be conducted at the conclusion of site grading to further evaluate the preliminary test results. Based upon the laboratory test results obtained, a consulting corrosion engineer may be retained to provide specific recommendations for foundations, utility piping, etc, as warranted. PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS Based on the previous field exploration and laboratory testing (CC, 2012), and our geotechnical engineering analysis, it is our opinion that the subject site is suitable for the proposed single-family residential development from a geotechnical engineering and geologic viewpoint, provided that the recommendations presented in the following sections are incorporated into the design and construction phases of site development. The primary geotechnical concerns with respect to the proposed development and improvements are: Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 11 GeoSoils, Inc. •Earth materials characteristics and depth to competent bearing material. •Expansive and corrosive nature of site soils. •Erosiveness of site earth materials. •Potential for perched water and saturated soils during and following site development. •Regional seismic activity. The recommendations presented herein consider these as well as other aspects of the site. The engineering analyses performed concerning site preparation and the recommendations presented herein have been completed using the information provided and obtained from our review, the initial geotechnical investigation by CC (2012), and the update geotechnical investigation by CC (2015). If any significant changes are made to proposed site development, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the recommendations of this report verified or modified in writing by this office. Foundation design parameters are considered preliminary until the foundation design, layout, and structural loads are provided to this office for review. RECOMMENDATIONS FOR ROUGH GRADING 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 verify and 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 is not expected to be a major factor in development of the site. However, due to the nature of the site materials, seepage may be encountered throughout the site along with perched water within drainage areas. In addition, perched water and seepage may be anticipated within the existing/active drainage course transecting the site, along fill/bedrock contacts, or along bedrock discontinuities (fractures or bedding plains) due to migration from adjacent drainage areas and development during or after periods of above normal or heavy precipitation or irrigation. Thus, subdrainage systems for the control of localized groundwater seepage should be anticipated. 4.Due to the noncohesive nature of some of the onsite materials, some caving and sloughing may be anticipated to be a factor in all subsurface excavations and Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 12 GeoSoils, Inc. trenching. Therefore, current local and state/federal safety ordinances for subsurface trenching should be enforced. 5.General Earthwork and Grading Guidelines are provided at the end of this report as Appendix C. Specific recommendations are provided below. Demolition/Grubbing 1.Any existing vegetation, tree remains, concrete spoils, surficial/subsurface structures, and any miscellaneous trash and debris should be removed from the areas of proposed grading. 2.Any organic-rich soils (exceeding 2 percent) encountered within the existing drainage course and the holding pond areas, should be removed from the site, or used in non-structural landscape areas. If not removed from the site, the landscape architect should review and approve the use of any organic-rich soils. 3.The project soils engineer should be notified of any previous foundation, irrigation lines, or other subsurface structures that are uncovered during the recommended removals, so that appropriate remedial recommendations can be provided. 4.Cavities or loose soils (including all previous exploratory test pits) 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 (ASTM D 1557). Treatment of Existing Ground 1.All undocumented artificial fill, and near-surface weathered/eroded compacted artificial fills (approximately upper 3 feet) should be removed to competent compacted artificial fills (i.e., greater than or equal to 90 percent relative compaction), if not removed by proposed cuts within areas proposed for settlement-sensitive improvements. A minimum of 2 feet of compacted fill should underlie the proposed footings. Actual depths of removals will be evaluated in the field during grading by the soil engineer. 2.If encountered during planned cuts in the northwest portions of the site, weathered sedimentary bedrock materials should be removed to competent bedrock, and overexcavated as discussed within the “transition and overexcavation areas” section below. 3.After the above removals, the upper 6 inches of the exposed compacted artificial fills, or sedimentary bedrock (if encountered) should be scarified, brought to at least Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 13 GeoSoils, Inc. optimum moisture content, and recompacted to a minimum relative compaction of 90 percent of the laboratory standard, prior to additional fill placement. 4.Existing, undocumented and compacted fills, weathered bedrock, etc., may be reused as compacted fill provided that major concentrations of vegetation and miscellaneous debris and any oversized rock (>12 inches) are removed prior to, or during fill placement. 5.Localized deeper removals may be necessary due to wet/saturated or yielding materials in the existing drainage and holding pond areas onsite. The project soils engineer/geologist should observe all removal areas during the grading. Fill Placement 1.Dry fill materials should be brought to at least optimum moisture, and placed in thin 6- to 8-inch lifts and mechanically compacted to obtain a minimum relative compaction of 90 percent of the laboratory standard. 2.Wet or saturated fill materials encountered during grading should be dried-back to no more than 2 percent above the soils optimum moisture content, and 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.Fill materials should be cleansed of major vegetation, organic materials, trash, and debris prior to placement. Fill materials should not exceed 2 percent organic matter. 3.Any oversized rock materials greater than 12 inches in diameter should be placed under the observation of the soils engineer. 4.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 a greater expansion value than the onsite materials previously encountered (CC, 2012). Transition and Overexcavation Areas In order to reduce the potential for differential settlements between sedimentary bedrock cut and fill materials or materials of differing engineering properties, the entire cut portion of cut/fill transitions should be overexcavated to a minimum depth of 3 feet below finish grade, or a maximum ratio of fill thickness of 3:1 (maximum to minimum), and replaced with compacted fill. In addition, building pads located entirely in bedrock cut areas, if any, should be overexcavated and capped with at least 3 feet of fill, or 2 feet below the bottom of proposed footings, whichever is greater. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 14 GeoSoils, Inc. SLOPE CONSIDERATIONS AND SLOPE DESIGN Based on our experience on adjacent projects, proposed cut and fill slopes constructed using onsite materials, to the heights proposed, should be grossly and surficially stable provided the recommendations contained herein are implemented during site development. General guidelines for slope construction are presented in Appendix C. All slopes should be designed and constructed in accordance with the minimum requirements of the 2022 CBC (CBSC, 2022), the City of Temecula and the County of Riverside, the recommendations contained in the General Earthwork, Grading Guidelines, and Preliminary Criteria section of this report (Appendix C), and the following: 1.Fill slopes should be designed and constructed at a 2:1 (horizontal to vertical) gradient or flatter and should not exceed 30 feet in vertical height, without a specific slope stability analyses. Fill slopes should be properly built and compacted to a minimum relative compaction of 90 percent throughout, including the slope surfaces. 2.Cut slopes should be designed at gradients of 2:1 (horizontal to vertical) or flatter and should not exceed 30 feet in vertical height, without a specific slope stability analyses. This should be provided at the 40-scale design stage, if necessary, when slope configurations are better understood. While stabilization of such slopes is not anticipated, locally adverse geologic conditions (i.e., daylighted joints/fractures or severely weathered bedrock) may be encountered which may require remedial grading or laying back of the slope to an angle flatter than the adverse geologic condition. 3.Local areas of highly to severely weathered bedrock may be present. Should these materials be exposed in cut slopes, the potential for long term maintenance or possible slope failure exists. Evaluation of cut slopes during grading would be necessary in order to identify any areas of severely weathered rock or non-cohesive sands. Should any of these materials be exposed during construction, the soils engineer/geologist, would assess the magnitude and extent of the materials and their potential affect on long-term maintenance or possible slope failures. Recommendations would then be made at the time of the field inspection. 4.Loose rock debris and fines remaining on the face of the cut slopes should be removed during grading. This can be accomplished by using a slope-board or by hand scaling, as warranted. 5.Where loose materials are exposed on the cut slopes, the project's engineering geologist would require that the slope be cleaned as described above prior to making their final inspection. Final approval of the cut slope can only be made after the slope being fully cut and cleaned. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 15 GeoSoils, Inc. PRELIMINARY RECOMMENDATIONS - FOUNDATIONS General The preliminary foundation design and construction recommendations provided herein are based upon our previous testing and engineering analysis of onsite earth materials by GSI based upon current standards of practice and newly adopted codes (2022 CBC). The proposed foundation systems should be designed and constructed in accordance with the guidelines contained within the 2022 CBC, the ACI (2014), and the differential settlement and angular distortion values updated herein. General recommendations for appurtenant/ancillary improvements and conventional foundation systems 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 update report. The foundation systems may be used to support the proposed structure, provided they are founded in competent bearing material. All findings, conclusions and recommendations in referenced geotechnical investigation reports by CC (2015 and 2012) remain pertinent and applicable except as specifically superceded herein. Additional recommendations are presented below. If 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. Upon request, GSI could provide additional input/consultation regarding soil parameters, as they relate to foundation design. Expansive Soils Preliminary laboratory testing (CC, 2012) indicates that the majority of onsite soils are very low to low in expansion potential. Should site grading result in areas underlain with expansive soils, foundation systems constructed within the influence of detrimentally expansive soils (i.e., E.I. > 20 and P.I. > 15) will require specific design to resist expansive soil effects per Sections 1808.6.1 or 1808.6.2 of the 2022 CBC, and should be reviewed by the project structural engineer. Preliminary Foundation Design The following foundation design recommendations are presented as a minimum criteria from a soils engineering viewpoint. 1.The foundation systems should be designed and constructed in accordance with guidelines presented in the 2022 CBC. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 16 GeoSoils, Inc. 2.An allowable bearing value of 2,000 pounds per square foot (psf) may be used for the design of footings. This value may be increased by 20 percent for each additional 12 inches in footing depth to a maximum value of 2,500 psf. These values may be increased by one-third when considering short duration seismic or wind loads. Foundations should not simultaneously bear on formation and engineered fill. 3.For foundations deriving passive resistance from engineered fill, a passive earth pressure may be computed as an equivalent fluid having a density of 250 pcf, with a maximum earth pressure of 2,500 psf. 4.The upper 6 inches of passive pressure should be neglected if not confined by slabs or pavement. 5.For lateral sliding resistance, a 0.35 coefficient of friction may be used for a concrete to soil contact when multiplied by the dead load. 6.When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. 7.All footing setbacks from slopes should comply with Figure 1808.7.1 of the 2022 CBC. GSI recommends a minimum horizontal setback distance of 7 feet as measured from the bottom, outboard edge of the footing to the slope face. 8.Footings for structures adjacent to retaining 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 “Preliminary Wall Design Parameters” section of this report. 9.Provided that the earthwork and foundation recommendations in this reported are adhered, foundations bearing on engineered fill should be minimally designed to accommodate a differential settlement of 1 inch over a 40-foot horizontal span (angular distortion = 1/480). Preliminary Foundation Construction Recommendations The following foundation construction recommendations are presented as a minimum criteria from a soils engineering viewpoint. These recommendations are intended to support planned improvements underlain by at least 7 feet of non-detrimentally expansive soils (i.e., E.I. < 21 and P.I. < 15). 1.Exterior and interior footings should be founded into engineered fill, or suitable formation, at minimum depths of 12 inches or 18 inches below the lowest adjacent grade, for planned one- or two-story floor loads, respectively, with footing width per Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 17 GeoSoils, Inc. Code. Isolated, exterior column and panel pads, or wall footings, should be at least 24 inches square, and founded at a minimum depth of 24 inches into properly engineered fill or suitable formation. Foundation embedment depth excludes concrete slab-on-grade or slab underlayment. 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 projects structural engineer. 2.All exterior column footings, and perimeter wall footings, should be tied together via grade beams in at least one direction for very low expansive soils, and two directions for low expansive soils. The grade beam should be at least 12 inches square in cross section, and should be provided with a minimum of one No. 4 reinforcing bar at the top, and one No. 4 reinforcing bar at the bottom of the grade beam. The base of the reinforced grade beam should be at the same elevation as the adjoining footings. 3.A grade beam, reinforced as previously recommended, and at least 12 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.A minimum concrete slab-on-grade thickness of 4.5 inches is recommended. Recommendations for floor slab underlayment are presented in a later section of this report. Concrete slabs should be reinforced with a minimum of No. 3 reinforcement bars placed at 18-inch on center, in two horizontally perpendicular directions (i.e., long axis and short axis). 5.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. 6.The slab subgrade should be pre-soaked to at least the soils “optimum moisture content,” to a depth of at least 12 inches, or depth of footing embedment, prior to the placement of underlayment sand and vapor retarder. Slab subgrade pre-soaking should be evaluated by the geotechnical consultant within 72 hours of the placement of the underlayment sand and vapor retarder. 7.Reinforced concrete mix design should conform to Exposure Classes “S0", “W0", and “C1” in Table 19.3.2.1 of ACI 318R-14. Post-Tension Foundation Systems On a preliminary basis, post-tension foundation systems will likely be recommended where the E.I. > 20 and P.I. > 15, and may also be used to mitigate the damaging effects of differential or seismic settlements on the proposed building foundations and slab-on-grade Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 18 GeoSoils, Inc. floors. The post-tension foundation designer may elect to exceed the minimal recommendations, provided herein, to increase slab stiffness performance. Post-tension (PT) design may be either ribbed or 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 “shovel” footings, but has a thicker slab than the ribbed-type. UTF perimeter footings may use an allowable vertical bearing value of 1,500 psf, if founded into approved engineered fill overlying dense formational materials. 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-tension foundations should be designed using sound engineering practice and be in accordance with local and 2022 CBC requirements and Post Tensioning Institute (PTI) methodologies (PTI; 2004, 2008, 2012, 2013, and 2014). Upon request, GSI can provide additional data/consultation regarding soil parameters as related to post-tension 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. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 19 GeoSoils, Inc. Perimeter Cut-Off Walls Perimeter cut-off walls should be at least 12 inches deep for very low expansive soil conditions. The cut-off walls may be integrated into the slab design or independent of the slab. The bottom of the perimeter cut-off wall should be designed to resist tension, using cable or reinforcement per the structural engineer. Post-Tension 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 “Design of Post-Tensioned Slabs on Ground, Third Edition” (PTI, 2004), together with its addendums and errata (PTI; 2008, 2012, 2013, and 2014). Post-Tension Foundation Soil Support Parameters The recommendations for soil support parameters have been provided based on the typical soil index properties for soils that are low to very high in expansion potential. The soil index properties are typically the upper bound values based on our experience and practice in the southern California area. Additional testing is recommended either during or following grading, and prior to foundation construction to further evaluate the soil conditions within the upper 7 to 15 feet of pad grade. 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 to bedrock Constant soil Suction (pf)3.6 Moisture Velocity 0.7 inches/month Effective Plasticity Index (P.I.)*< 15-50 * - The weighted plasticity index should be evaluated for the upper 13 feet of foundation soils either during or following grading. Based on the above, the recommended post-tension soil support parameters are tabulated below: Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 20 GeoSoils, Inc. TABLE 1 - POST-TENSION FOUNDATION DESIGN DESIGN PARAMETER(4)VERY LOW TO LOW EXPANSION(5) (E.I. = 0-50) em center lift 9.0 feet em edge lift 5.2 feet ym center lift 0.4 inches ym edge lift 0.7 inch Bearing Value (1)1,500 psf (1) Lateral Pressure 250 psf Subgrade Modulus (k)100 pci/inch Minimum Perimeter Footing Embedment (2)12 inches (1) Internal bearing values within the perimeter of the post-tension slab for very low to low expansive soil conditions may be increased to 2,000 psf for a minimum embedment of 12 inches, then by 20 percent for each additional foot of embedment to a maximum of 2,500 psf. (2) For medium to very high expansive soil conditions, internal bearing values within the perimeter of the post-tension slab may be increased to 1,500 psf for a minimum embedment of 12 inches, then by 20 percent for each additional foot of embedment to a maximum of 2,000 psf. (3) As measured below the lowest adjacent compacted subgrade surface (not including slab underlayment layer thickness). (4) Post-tension slab design should also be evaluated with respect to the potential differential settlements provided in this report. (5) Category Criteria: Category I Expansion Index < 50 (very low to low), or Max fill less than 35 feet thick, or fill differential less than 10 feet. The parameters are considered minimums and may not be adequate to represent all expansive soils and site conditions such as adverse drainage or improper landscaping and maintenance. The above parameters are applicable provided the grades around the structure provide positive drainage that is maintained away from the building foundation. 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 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. All exterior columns not supported by the post-tensioned foundation should be supported by 24 square inch isolated footings extending at least 24 inches into approved engineered fill. Exterior column footings should be tied to the post-tensioned foundation with 12 square-inch, reinforced grade beams in at least two directions for low expansive soils. SOIL MOISTURE TRANSMISSION CONSIDERATIONS GSI has evaluated the potential for vapor or water transmission through the concrete floor slab, in light of typical floor coverings and improvements. Please note that slab moisture emission rates range from about 2 to 27 lbs/24 hours/1,000 square feet from a typical slab (Kanare, 2005), while floor covering manufacturers generally recommend Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 21 GeoSoils, Inc. 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, 2023). 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. Vapor transmission will occur in new slab-on-grade floors as a result of chemical reactions taking place within the curing concrete. Vapor transmission through concrete floor slabs as a result of concrete curing has the potential to adversely affect sensitive floor coverings depending on the thickness of the concrete floor slab and the duration of time between the placement of concrete and the floor covering. It is possible that a slab moisture sealant may be needed prior to the placement of sensitive floor coverings if a thick slab-on-grade floor is used and the time frame between concrete and floor covering placement is relatively short. Considering the E.I. test results presented herein, and known soil conditions in the region, the anticipated typical water vapor transmission rates, floor coverings, and improvements (to be chosen by the Client or project architect) that can tolerate vapor transmission rates without significant distress, the following alternatives are provided: •Concrete slabs should be increased in thickness. •Concrete slab underlayment should consist of a 15-mil vapor retarder, or equivalent, with all laps sealed per the 2022 CBC and the manufacturer’s recommendation. The vapor retarder should comply with the ASTM E 1745 - Class A criteria, and be installed in accordance with ACI 302.1R-04 and ASTM E 1643. •The 15-mil vapor retarder (ASTM E 1745 - Class A) should be installed per the recommendations of the manufacturer, including all penetrations (i.e., pipe, ducting, rebar, etc.). •Concrete slabs, including the garage areas, should be underlain by 2 inches of clean sand (SE > 30) above a 15-mil vapor retarder (ASTM E-1745 - Class A, per Engineering Bulletin 119 [Kanare, 2005]) 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. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 22 GeoSoils, Inc. ACI 302.1R-04 (2004) 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 or testing will be necessary for the cushion or sand layer for moisture content, and relatively uniform thicknesses, prior to the placement of concrete. •The vapor retarder shall be underlain by 2 inches of clean sand (SE > 30) placed directly on the prepared, moisture conditioned, subgrade and should be sealed to provide a continuous retarder under the entire slab, as discussed above. •Concrete should have a maximum water/cement ratio of 0.50. This does not supercede Table 19.3.2.1 of ACI (2014) for corrosion or other corrosive requirements. Additional concrete mix design recommendations should be provided by the structural consultant or waterproofing specialist. Concrete finishing and workability should be addressed by the structural consultant and a waterproofing specialist. •Where slab water/cement ratios are as indicated herein, 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 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. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 23 GeoSoils, Inc. PRELIMINARY WALL DESIGN PARAMETERS General Recommendations for the design and construction of conventional masonry retaining walls are provided below. Recommendations for specialty walls (i.e., crib, earthstone, mechanically stabilized earth [MSE], gravity, etc.) can be provided upon request, and would be based on site specific conditions. 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 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. Preliminary Retaining Wall Foundation Design Preliminary foundation design for retaining walls should incorporate the following recommendations: Minimum Footing Embedment - 18 inches below the lowest adjacent grade (excluding landscape layer [upper 6 inches]). Minimum Footing Width - 24 inches Allowable Bearing Pressure - An allowable 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 dense formational materials. This pressure may be increased by one-third for short-term wind or seismic loads. Passive Earth Pressure - A passive earth pressure of 250 pcf with a maximum earth pressure of 2,500 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 used 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. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 24 GeoSoils, Inc. Backfill Soil Density - Soil densities ranging between 125 pcf and 135 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). Any retaining wall footings near the perimeter of the site will likely need to be deepened into unweathered bedrock or alluvial deposits for adequate vertical and lateral bearing support. All retaining wall footing setbacks from slopes should comply with Figure 1808.7.1 of the 2022 CBC. GSI recommends a minimum horizontal setback distance of 7 feet as measured from the bottom, outboard edge of the footing to the 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 native 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 the City of Temecula or County of Riverside 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 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: Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 25 GeoSoils, Inc. 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 (1) 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, where H is the height of the wall. (2) SE > 30, P.I. < 15, E.I. < 21, and < 10% passing No. 200 sieve. (3) E.I. = 0 to 50, SE > 30, P.I. < 15, E.I. < 21, and < 15% passing No. 200 sieve. 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 2022 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 18H 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 0.6 H 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 18H. For restrained walls, the pressure should be applied as a rectangular distribution. Please note this is for local wall stability only. The 18H 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 18H seismic surcharge is derived from the formula: Ph = d C ah C (tH Where:Ph =Seismic increment. ah =Probabilistic horizontal site acceleration with a percentage of “g”. (t =total unit weight (125 to 135 pcf for site soils @ 90% relative compaction). H =Height of the wall from the bottom of the footing or point of pile fixity. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 26 GeoSoils, Inc. 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. = 20, continuous Class 2 permeable drain materials should be used behind the wall. This material should be continuous (i.e., full length) 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 20 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), 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). 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 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. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 27 12 inches (1) Waterproofing membrane Provide surface drainage via an engineered V-ditch (see civil plans for details) (5) Weep hole Proposed grade sloped to drain per precise civil drawings (4) Pipe (3) Filter fabric (2) Gravel 2:1 (h:v) slope 1:1 (h:v) or flatter backcut to be properly benched Slope or level Native backfill Very Low to Low Expansive soils, E.I. <50, P.I. <15 (1) Waterproofing membrane. (2) Gravel: Clean, crushed, 3 4 to 1 1 2 inch. (3) Filter fabric: Mirafi 140N or approved equivalent. (4) Pipe: 4-inch-diameter perforated PVC, Schedule 40, or approved alternative with minimum of 1 percent gradient sloped to suitable, approved outlet point (perforations down). (5) Weep holes: For CMU walls, Omit grout every other block, at or slightly above finished surface. For reinforced concrete walls, minimum 2-inch diameter weep holesspaced at 20 foot centers along the wall and placed 3 inches above finished surface. Design civil engineer to provide drainage at toe of wall. No weep holes for below-grade walls. (6) Footing: If bench is created behind the footing greater than the footing width using level fill or cut natural earth materials, an additional "heel " drain will likely be required by geotechnical consultant. Footing and wall design by others (6) Footing Structural footing or settlement-sensitive improvement H H/3 CMU or reinforced-concrete wall 6 inches (1) Waterproofing membrane (optional)Provide surface drainage via engineered V-ditch (see civil plan details) (5) Weep hole Proposed grade sloped to drain per precise civil drawings (4) Pipe (3) Filter fabric (2) Composite drain CMU or reinforced-concrete wall 2:1 (h:v) slope 1:1 (h:v) or flatter backcut to be properly benched Slope or level Native backfill Very Low to Low Expansive soils E.I. <50, P.I. <15 (1) Waterproofing membrane (optional): Liquid boot or approved mastic equivalent. (2) Drain: Miradrain 6000 or J-drain 200 or equivalent for non-waterproofed walls; Miradrain 6200 or J-drain 200 or equivalent for waterproofed walls (all perforations down). (3) Filter fabric: Mirafi 140N or approved equivalent; place fabric flap behind core. (4) Pipe: 4-inch-diameter perforated PVC, Schedule 40, or approved alternative with minimum of 1 percent gradient to proper outlet point (perforations down). (5) Weep holes: For CMU walls, Omit grout every other block, at or slightly above finished surface. For reinforced concrete walls, minimum 2-inch diameter weep holesspaced at 20 foot centers along the wall and placed 3 inches above finished surface. Design civil engineer to provide drainage at toe of wall. No weep holes for below-grade walls. (6) Gravel: Clean, crushed, 3 4 to 1 1 2 inch. (7) Footing: If bench is created behind the footing greater than the footing width using level fill or cut natural earth materials, an additional "heel " drain will likely be required by geotechnical consultant. (6) 1 cubic foot of 3 4 -inch crushed rock (7) Footing Footing and wall design by others Structural footing or settlement-sensitive improvement (1) Waterproofing membrane Provide surface drainage (5) Weep hole Proposed grade sloped to drain per precise civil drawings (4) Pipe (3) Filter fabric (2) Gravel CMU or reinforced-concrete wall 2:1 (h:v) slope 1:1 (h:v) or flatter backcut to be properly benched Slope or level (8) Native backfill (1) Waterproofing membrane: Liquid boot or approved masticequivalent. (2) Gravel: Clean, crushed, 3 4 to 1 1 2 inch. (3) Filter fabric: Mirafi 140N or approved equivalent. (4) Pipe: 4-inch-diameter perforated PVC, Schedule 40, or approved alternative with minimum of 1 percent gradient to proper outlet point (perforations down). (5) Weep hole: For CMU walls, Omit grout every other block, at or slightly above finished surface. For reinforced concrete walls, minimum 2-inch diameter weep holesspaced at 20 foot centers along the wall and placed 3 inches above finished surface. Design civil engineer to provide drainage at toe of wall. No weep holes for below-grade walls. (6) Clean sand backfill: Must have sand equivalent value (S.E.) of 35 or greater; can be densified by water jetting upon approval by geotechnical engineer. (7) Footing: If bench is created behind the footing greater than the footing width using level fill or cut natural earth materials, an additional "heel " drain will likely be required by geotechnical consultant. (8) Native backfill: If E.I. <21 and S.E. >35 then all sand requirements also may not be required and will be reviewed by the geotechnical consultant. (6) Clean sand backfill H ±12 inches H/2 minimum Heel width (7) Footing Footing and wall design by others Structural footing or settlement-sensitive improvement GeoSoils, Inc. 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. ONSITE STORM WATER QUALITY BEST MANAGEMENT PRACTICE (BMP) SYSTEMS Based on our review of the tentative tract map prepared by MBI (2022), onsite infiltration-runoff retention system (OIRRS) basins are planned for Best Management Practices (BMP’s) or Low Impact Development (LID) principles for the project. As such, certain guidelines must be followed in the planning, design, and construction of such systems. Such systems, 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 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 or estimated size of the OIRRS, may require additional infiltration testing. Locally, relatively impermeable formations include: clayey surficial soils, igneous and metamorphic bedrock (as encountered onsite), as well as future fine grained fill soils. Some of the methods which are used 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, and project civil engineer. Applicable governing agency requirements should be reviewed and included in design considerations. The following geotechnical guidelines should be considered when designing onsite infiltration-runoff retention systems: Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 31 GeoSoils, Inc. •It is not good engineering practice to allow water to saturate soils, especially near slopes or improvements; however, the controlling agency/authority may now require this. •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. •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). •Where infiltration systems are located near slopes or improvements, impermeable liners and subdrains should be used along the bottom or sides of bioretention swales/basins located within the influence of such slopes and structures. Impermeable liners used in conjunction with bioretention 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, with a maximum 3:1 (h:v) slope inclination, or flatter, and meets the following minimum specifications: Solid Soils 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): 32 (lb/in-width, min.); and Tear Strength (ASTM D1004): 8 (lb/in, 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). •Subdrains should consist of at least 4-inch diameter Schedule 40 or SDR 35 drain pipe with perforations oriented down. The drain pipe should be sleeved with a filter sock. •Storm drain, standpipes, and utilities that cross BMPs should be slurried with a 2-sack mix, to 5 feet outside the structure. •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 or pile/pier supported improvements may be used. •Infiltrations systems should not be installed adjacent to pavement or hardscape improvements. Alternatively, deepened/thickened edges and curbs or impermeable liners may be used in areas adjoining the OIRRS. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 32 GeoSoils, Inc. •As with any OIRRS, localized ponding and groundwater seepage should be anticipated. The potential for seepage or perched groundwater to occur after site development should be disclosed to all interested/affected parties. •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. •Infiltration systems should not be installed where the vertical separation of impermeable bedrock is less than 5 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) 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, 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 or complete replacement of the filter media (e.g., sand, gravel, filter fabrics, topsoils, mulch, etc.) or other components used 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. •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 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, or seepage along the utility trench line backfill. If utility trenches cross 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 may also be subject to piping of fines into open-graded gravel Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 33 GeoSoils, Inc. backfill layers unless separated from overlying or adjoining OIRRS by geotextiles or slurry backfill. •The use of OIRRS above existing utilities that might degrade/corrode with the introduction of water/seepage should be avoided. DRIVEWAYS, CONCRETE APRONS, FLATWORK, AND OTHER IMPROVEMENTS The 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 that end, it is recommended that the developer should notify any owners or interested/affected parties of this long-term potential for distress. To reduce the likelihood of distress, the following recommendations are presented for all exterior flatwork: 1.The subgrade area for sidewalk slabs should be compacted to achieve a minimum 90 percent relative compaction, the subgrade area for access drive slabs and concrete aprons should be compacted to achieve a minimum 95 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 12 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 concrete placement. 2.Exterior concrete slabs should be cast over a non-yielding surface, consisting of a 4-inch layer of Class 2 base, crushed rock, gravel, or clean sand (or City minimum, whichever is greater), that should be compacted and level prior to placement of concrete. If very low expansive soils are present, the base, rock, gravel, or sand may be deleted. The layer or subgrade should be wet-down completely prior to placement of concrete, to minimize loss of concrete moisture to the surrounding earth materials. 3.Exterior sidewalk slabs should be a minimum of 4 inches thick. Access drive slabs should be a minimum of 5 inches thick. 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. Trash disposal (dumpster) area aprons should be a minimum of 6 inches thick and meet minimum City standards, as necessary. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 34 GeoSoils, Inc. 4.Curbs next to slopes should have a thickened edge similar to drives and approaches. 5.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 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. Presoaking, as indicated earlier, is recommended for slab subsoils. 6.No traffic should be allowed upon the newly placed 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. 7.Access drives, sidewalks, and patio/exterior slabs adjacent to the structure should be separated from the structure 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. 8.Planters and walls (sound walls or retaining walls) should not be tied to the structure. 9.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. 10.Any masonry landscape or sound 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. 11.If settlement concerns or expansive soils are present, utilities may be enclosed within a closed utilidor (vault) or designed with flexible connections to accommodate differential settlement and expansive soil conditions. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 35 GeoSoils, Inc. 12.Positive site drainage should be maintained at all times. Finish grade on the building pad should provide a minimum of 1 to 2 percent fall to the street, as indicated herein. Drainage reversals could occur, including post-construction settlement, if relatively flat drainage gradients are not periodically maintained by the owner or interested/affected parties. 13.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. 14.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 (PCA) 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. DEVELOPMENT CRITERIA Slope Deformation Compacted fill slopes designed using customary factors of safety for gross or surficial stability and constructed in general accordance with the design specifications should be expected to undergo some differential vertical heave or settlement in combination with differential lateral movement in the out-of-slope direction, after grading. This post-construction movement occurs in two forms: slope creep, and lateral fill extension (LFE). Slope creep is caused by alternate wetting and drying of the fill soils which results in slow downslope movement. This type of movement is expected to occur throughout the life of the slope, and is anticipated to potentially affect improvements or structures (e.g., separation or cracking), placed near the top-of-slope, up to a maximum distance of approximately 15 feet from the top-of-slope, depending on the slope height. This movement generally results in rotation and differential settlement of improvements located within the creep zone. LFE occurs due to deep wetting from irrigation and rainfall on slopes comprised of expansive materials. Although some movement should be expected, long-term movement from this source may be minimized, but not eliminated, by placing the fill throughout the slope region, wet of the fill’s optimum moisture content. It is generally not practical to attempt to eliminate the effects of either slope creep or LFE. Suitable mitigative measures to reduce the potential of lateral deformation typically include: setback of improvements from the slope faces (per 2022 CBC), positive structural separations (i.e., joints) between improvements, and stiffening and deepening of foundations. Expansion joints in walls should be placed no greater than 20 feet on-center, and in accordance with the structural engineer’s recommendations. All of these measures Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 36 GeoSoils, Inc. are recommended for design of structures and improvements. The ramifications of the above conditions, and recommendations for mitigation, should be provided to each homeowner or any homeowners association. 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 using 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 capable of surviving the prevailing climate. Jute-type matting or other fibrous covers may aid in allowing the establishment of a sparse plant cover. Using 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 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, retaining walls, etc.). Pad drainage should be directed toward the street or other approved area(s). 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 Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 37 GeoSoils, Inc. 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 structures be eliminated for a minimum distance of 10 feet. As an alternative, closed-bottom type planters could be used. 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. 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. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 38 GeoSoils, Inc. Site Improvements If any additional improvements (e.g., trash enclosures, walls, 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. 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 after 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. Trenching/Temporary Construction Backcuts Considering the nature of the onsite earth materials, 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. Given the potentially erosive nature of the low expansive (low cohesive) soils, poor drainage or heavy Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 39 GeoSoils, Inc. rain events could destabilize trenches. Should adverse conditions exist, appropriate recommendations would be offered at that time. The above recommendations should be provided to any contractors or subcontractors, or homeowners, etc., that may perform such work. 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 used 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. 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 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 or backfill. •After excavation of building footings, retaining wall footings, and free standing walls footings, prior to the placement of reinforcing steel or concrete. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 40 GeoSoils, Inc. •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., Stego Wrap, Husky Guard, 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, after the issuance of this report. •When any developer or homeowner improvements, such as flatwork, 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, 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 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. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 41 GeoSoils, Inc. 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 potential distress, the foundation or improvement’s designer should confirm to GSI and the governing agency, in writing, that the proposed foundations or improvements can tolerate the amount of differential settlement 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 or further geotechnical studies may be warranted. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 42 GeoSoils, Inc. LIMITATIONS The materials encountered on the project site and used 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. The findings of this study are valid as of the present date. However, changes in the conditions of a property can occur with the passage of time, whether they be due to natural processes or the works of man on this or adjacent properties. In addition, changes in applicable or inappropriate standards may occur, whether they result from legislation or the broadening of knowledge. Accordingly, the findings of this study may be invalidated wholly or partially by changes outside our control. Therefore, this study and the recommendations contained herein are subject to review and should not be relied upon after a period of three years. 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. Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 43 GeoSoils, Inc. 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 Stephen J. Coover Engineering Geologist, CEG 2377 Geotechnical Engineer, GE 2057 TAG/JPF/SJC/sh Enclosures:Appendix A - References Appendix B - Boring Logs by Converse Consultants (2012) Appendix C - General Earthwork, Grading Guidelines, and Preliminary Criteria Distribution:(1) Addressee (PDF via email) (1) MDS Consulting; Attention: Mr. Ed Lenth, P.E. (PDF via email) Woodside 05S, LP W.O. 8577-A-SC Tentative Tract 36483, City of Temecula April 7, 2023 File:e:\wp21\murr\rc8500\8577a.gur Page 44 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 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. _____, 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. _____, 2010, Minimum design loads for buildings and other structures, ASCE Standard ASCE/SEI 7-10. Blake, T.F., 2000, EQFAULT, A computer program for the deterministic prediction of peak horizontal acceleration from digitized California faults; updated to 2021. California Building Standards Commission, 2022, California Building Code, California Code of Regulations, Title 24, Part 2, Volumes 1 and 2, based on the 2021 International Building Code, effective January 1, 2023. California Code of Regulations, 2011, CAL-OSHA State of California Construction and Safety Orders, dated February. California Department of Conservation, California Geological Survey (CGS), 2018a, 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. GeoSoils, Inc. _____, 2018b, Earthquake zones of required investigation, Temecula quadrangle, revised official map; effective January 11. California Department of Water Resources, 2023, Water Data Library, interactive website, (http://wdl.water.ca.gov/waterdatalibrary/). California Office of Statewide Health Planning and Development (OSHPD), 2023, Seismic design maps, https://seismicmaps.org/. Cao, T., Bryant, W.A., Rowshandel, B., Branum, D., and Wills, C.J., 2003, The revised 2002 C a l i f o r n i a p r o b a b i l i s t i c s e i s m i c h a z a r d m a p s , d a t e d J u n e , https://www.conservation.ca.gov/cgs/Documents/PSHA/2002_CA_Hazard_Maps .pdf. Converse Consultants, 2015, Geotechnical investigation report for a single-family development, Tentative Tract 36483, northwest of Temecula Parkway and Butterfield Stage Road, City of Temecula, Riverside County, California, P.N. 12-81- 173-02, dated March 27. _____, 2012, Geotechnical investigation report for a commercial and multi-family development, Planning Area 4; approximately 43 acre site, northwest of the intersection at Temecula Parkway & Butterfield Stage Road, City of Temecula, Riverside County, California, P.N. 12-81-173-01, dated August 7. County of Riverside Transportation and Land Management Agency, Building and Safety Department, Planning Department, Transportation Department, 2000, Technical guidelines for review of geotechnical and geologic reports. Google Earth Pro - v7.3.4, 2023, by Google, LLC, https://www.google.com/ earth/download/gep/agree.html, [accessed March 20, 2023]. Kanare, Howard, M., 2005, Concrete Floors and Moisture, Engineering Bulletin 119, Portland Cement Association, pp. 35-42. Kennedy, M.P., 2000, Geologic map of the Pechanga 7.5" quadrangle, San Diego and Riverside Counties, California: a digital database, California Division of Mines and Geology, version 1.0. Michael Baker International, 2022, In the City of Temecula, County of Riverside, State of California, Tentative Tract No. 36483, for residential purposes, 2 sheets, scale 1"=60', J.N. 139600, plotted July 25. State of California, 2023, Civil Code, Sections 895 et seq. Woodside 05S, LP Appendix A File:e:\wp21\murr\rc8500\8577a.gur Page 2 GeoSoils, Inc. U.S. Geological Survey, 2019, USGS tools for site-specific ground motion hazard analysis based on ASCE 7-16, dated November 19. Wire Reinforcement Institute, Inc., 2016, Manual of standard practice, structural welded wire reinforcement, dated December. Woodside 05S, LP Appendix A File:e:\wp21\murr\rc8500\8577a.gur Page 3 GeoSoils, Inc. APPENDIX B BORING LOGS BY CONVERSE CONSULTANTS (2012) 1 A-1 Drawing No.Project No. 12-81-173-01Commercial And Multi-Family Development Planning Area 4; Approximately 43 Acre Site City of Temecula, Riverside County, California For: Cal-Paseo Del Sol, LLCProject ID: 12-81-173-01.GPJ; Template: KEY (LITTLE OR NO FINES) INORGANIC SILTS AND VERY FINE SANDS, ROCK FLOUR, SILTY OR CLAYEY FINE SANDS OR CLAYEY SILTS WITH SLIGHT PLASTICITY Soft Medium Stiff Very StiffVery Soft Hard DRIVE SAMPLE 2.42" I.D. sampler (CMS). DRIVE SAMPLE 5-8< 2 < 3> 80 CH GRAVELS WITH FINES CLEAN SANDS GRAVEL AND GRAVELLY SOILS CLEAN GRAVELS INORGANIC CLAYS OF HIGH PLASTICITY GP CLAYEY SANDS, SAND - CLAY MIXTURES GRAPH LIQUID LIMIT LESS THAN 50 SILTY GRAVELS, GRAVEL - SAND - SILT MIXTURES OH SC SILTS AND CLAYS MORE THAN 50% OF COARSE FRACTION PASSING ON NO. 4 SIEVE MORE THAN 50% OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE SILTY SANDS, SAND - SILT MIXTURES POORLY-GRADED SANDS, GRAVELLY SAND, LITTLE OR NO FINES (LITTLE OR NO FINES) OL WELL-GRADED GRAVELS, GRAVEL - SAND MIXTURES, LITTLE OR NO FINES SANDS WITH FINES CL HIGHLY ORGANIC SOILS PT MORE THAN 50% OF MATERIAL IS SMALLER THAN NO. 200 SIEVE SIZE SM WELL-GRADED SANDS, GRAVELLY SANDS, LITTLE OR NO FINES (APPRECIABLE AMOUNT OF FINES) SP 26-50 SW COARSE GRAINED SOILS POORLY-GRADED GRAVELS, GRAVEL - SAND MIXTURES, LITTLE OR NO FINES CLAYEY GRAVELS, GRAVEL - SAND - CLAY MIXTURES SAMPLE TYPE LETTER INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTS SAND AND SANDY SOILS INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE SAND OR SILTY SOILS SOIL CLASSIFICATION CHART UNIFIED SOIL CLASSIFICATION AND KEY TO BORING LOG SYMBOLS MORE THAN 50% OF COARSE FRACTION RETAINED ON NO. 4 SIEVE Plasticity Grain Size Analysis Passing No. 200 Sieve Sand Equivalent Expansion Index Compaction Curve Hydrometer Disturb CLASSIFICATION pi ma wa se ei max h Dist. Consolidation Collapse Test Resistance (R) Value Chemical Analysis Electrical Resistivity Permeability Soil Cement Pocket Penetrometer Direct Shear Direct Shear (single point) Unconfined Compression Triaxial Compression Vane Shear STRENGTH p ds ds* uc tx vs c col r ca er perm sc (APPRECIABLE AMOUNT OF FINES) GC DESCRIPTIONS BORING LOG SYMBOLS NOTE: DUAL SYMBOLS ARE USED TO INDICATE BORDERLINE SOIL CLASSIFICATIONS LABORATORY TESTING ABBREVIATIONS TEST TYPE (Results shown in Appendix B) ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY FINE GRAINED SOILS SILTS AND CLAYS ML TYPICAL Split barrel sampler in accordance with ASTM D-1586-84 Standard Test Method SPT (N) No recovery BULK SAMPLE GROUNDWATER WHILE DRILLING GROUNDWATER AFTER DRILLING 40 - 60 60 - 80< 20 4 - 11 11 - 30 31 - 50 > 50 < 5 5 - 12 13 - 35 36 - 60 > 60 Relative Density (%) Very Loose Consistency 2-4 9-15 16-30 CA Sampler > 30 > 503-6 7-12 13-25 MH GM GW SYMBOLS PEAT, HUMUS, SWAMP SOILS WITH HIGH ORGANIC CONTENTS LIQUID LIMIT GREATER THAN 50 MAJOR DIVISIONS STANDARD PENETRATION TEST Dense < 4SPT (N) CA Sampler Very DenseLooseMedium 20 - 40 Apparant Density Converse Consultants FILL: SILTY SAND (SM): fine to coarse-grained, brown. - concrete fragments CLAYEY SAND (SC): fine to coarse-grained, yellow-brown. SILTY SAND (SM): fine to coarse-grained, brown. - trace clay 13/9/8 6/9/15 5/6/4 6/10/14 4/7/7 5/14/20 8/11/14 7 15 10 8 14 126 123 111 120 115 ma,max r 12-81-173-01 A-2a Drawing No. De p t h ( f t ) Checked By: Ground Surface Elevation (ft): Gr a p h i c Lo g CG Equipment: Project No. CME 75/ 8" HSA Log of Boring No. BH- 1 Logged by:Dates Drilled: NOT ENCOUNTERED Driving Weight and Drop:140 lbs / 30 in Depth to Water (ft): SUMMARY OF SUBSURFACE CONDITIONS 5/30/2012 This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.De p t h ( f t ) SM SAMPLES Gr a p h i c Lo g BU L K ±1142 SUMMARY OF SUBSURFACE CONDITIONS DR I V E BL O W S MO I S T U R E DR Y U N I T W T . (p c f ) OT H E R 5 10 15 20 25 30 Commercial And Multi-Family Development Planning Area 4; Approximately 43 Acre Site City of Temecula, Riverside County, California For: Cal-Paseo Del Sol, LLC Converse Consultants Project ID: 12-81-173-01.GPJ; Template: LOG End of boring at 51.5 feet. No groundwater encountered. Borehole backfilled loose with soil cuttings on 5/30/12. ALLUVIUM (Qal): SILTY SAND (SM): fine to coarse-grained, brown. 9/14/20 8/11/12 10/15/23 6/9/8 6 9 122 117 12-81-173-01 A-2b Drawing No. De p t h ( f t ) Checked By: Ground Surface Elevation (ft): Gr a p h i c Lo g CG Equipment: Project No. CME 75/ 8" HSA Log of Boring No. BH- 1 Logged by:Dates Drilled: NOT ENCOUNTERED Driving Weight and Drop:140 lbs / 30 in Depth to Water (ft): SUMMARY OF SUBSURFACE CONDITIONS 5/30/2012 This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.De p t h ( f t ) SM SAMPLES Gr a p h i c Lo g BU L K ±1142 SUMMARY OF SUBSURFACE CONDITIONS DR I V E BL O W S MO I S T U R E DR Y U N I T W T . (p c f ) OT H E R 40 45 50 Commercial And Multi-Family Development Planning Area 4; Approximately 43 Acre Site City of Temecula, Riverside County, California For: Cal-Paseo Del Sol, LLC Converse Consultants Project ID: 12-81-173-01.GPJ; Template: LOG End of boring at 16.5 feet. No groundwater encountered. Borehole backfilled loose with soil cuttings on 5/30/12. FILL: SILTY SAND (SM): fine to coarse-grained, yellow-brown. 12/12/16 9/8/9 6/7/9 12/10/13 5 8 11 10 115 115 116 119 12-81-173-01 A-3 Drawing No. De p t h ( f t ) Checked By: Ground Surface Elevation (ft): Gr a p h i c Lo g CG Equipment: Project No. CME 75/ 8" HSA Log of Boring No. BH- 2 Logged by:Dates Drilled: NOT ENCOUNTERED Driving Weight and Drop:140 lbs / 30 in Depth to Water (ft): SUMMARY OF SUBSURFACE CONDITIONS 5/30/2012 This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.De p t h ( f t ) SM SAMPLES Gr a p h i c Lo g BU L K ±1127 SUMMARY OF SUBSURFACE CONDITIONS DR I V E BL O W S MO I S T U R E DR Y U N I T W T . (p c f ) OT H E R 5 10 15 Commercial And Multi-Family Development Planning Area 4; Approximately 43 Acre Site City of Temecula, Riverside County, California For: Cal-Paseo Del Sol, LLC Converse Consultants Project ID: 12-81-173-01.GPJ; Template: LOG End of boring at 16.5 feet. No groundwater encountered. Borehole backfilled loose with soil cuttings on 5/30/12. FILL: SILTY SAND (SM): fine to coarse-grained, asphalt and concrete fragments, brown. -fine to medium-grained - fine to coarse-grained 11/9/7 3/3/6 5/6/7 8/8/14 7 11 13 8 121 114 110 125 ds,col 12-81-173-01 A-4 Drawing No. De p t h ( f t ) Checked By: Ground Surface Elevation (ft): Gr a p h i c Lo g CG Equipment: Project No. CME 75/ 8" HSA Log of Boring No. BH- 3 Logged by:Dates Drilled: NOT ENCOUNTERED Driving Weight and Drop:140 lbs / 30 in Depth to Water (ft): SUMMARY OF SUBSURFACE CONDITIONS 5/30/2012 This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.De p t h ( f t ) SM SAMPLES Gr a p h i c Lo g BU L K ±1129 SUMMARY OF SUBSURFACE CONDITIONS DR I V E BL O W S MO I S T U R E DR Y U N I T W T . (p c f ) OT H E R 5 10 15 Commercial And Multi-Family Development Planning Area 4; Approximately 43 Acre Site City of Temecula, Riverside County, California For: Cal-Paseo Del Sol, LLC Converse Consultants Project ID: 12-81-173-01.GPJ; Template: LOG End of boring at 16.5 feet. No groundwater encountered. Borehole backfilled loose with soil cuttings on 5/30/12. FILL: SILTY SAND (SM): fine to coarse-grained, asphalt and concrete fragments at 2' bgs, brown. SANDY SILT (ML): fine-grained sand, brown. 6/9/26 11/11/15 5/7/7 3/4/7 13 6 14 10 110 114 111 123 ma.ei 12-81-173-01 A-5 Drawing No. De p t h ( f t ) Checked By: Ground Surface Elevation (ft): Gr a p h i c Lo g CG Equipment: Project No. CME 75/ 8" HSA Log of Boring No. BH- 4 Logged by:Dates Drilled: NOT ENCOUNTERED Driving Weight and Drop:140 lbs / 30 in Depth to Water (ft): SUMMARY OF SUBSURFACE CONDITIONS 5/30/2012 This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.De p t h ( f t ) SM SAMPLES Gr a p h i c Lo g BU L K ±1125 SUMMARY OF SUBSURFACE CONDITIONS DR I V E BL O W S MO I S T U R E DR Y U N I T W T . (p c f ) OT H E R 5 10 15 Commercial And Multi-Family Development Planning Area 4; Approximately 43 Acre Site City of Temecula, Riverside County, California For: Cal-Paseo Del Sol, LLC Converse Consultants Project ID: 12-81-173-01.GPJ; Template: LOG End of boring at 16.5 feet. No groundwater encountered. Borehole backfilled loose with soil cuttings on 5/30/12. FILL: SILTY SAND (SM): fine to coarse-grained, yellow-brown. SANDY SILT (ML): fine-grained sand, dark brown. 10/16/7 10/7/6 7/9/15 8/11/16 6 9 12 12 113 119 120 116 ca,er r 12-81-173-01 A-6 Drawing No. De p t h ( f t ) Checked By: Ground Surface Elevation (ft): Gr a p h i c Lo g CG Equipment: Project No. CME 75/ 8" HSA Log of Boring No. BH- 5 Logged by:Dates Drilled: NOT ENCOUNTERED Driving Weight and Drop:140 lbs / 30 in Depth to Water (ft): SUMMARY OF SUBSURFACE CONDITIONS 5/30/2012 This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.De p t h ( f t ) SM SAMPLES Gr a p h i c Lo g BU L K ±1130 SUMMARY OF SUBSURFACE CONDITIONS DR I V E BL O W S MO I S T U R E DR Y U N I T W T . (p c f ) OT H E R 5 10 15 Commercial And Multi-Family Development Planning Area 4; Approximately 43 Acre Site City of Temecula, Riverside County, California For: Cal-Paseo Del Sol, LLC Converse Consultants Project ID: 12-81-173-01.GPJ; Template: LOG End of boring at 16.5 feet. No groundwater encountered. Borehole backfilled loose with soil cuttings on 5/30/12. FILL: SILTY SAND (SM): fine to coarse-grained, brown. - trace clay, trace gravel up to 1/2" in largest dimension SAND WITH SILT (SP-SM): fine to medium-grained, brown. SILTY SAND (SM): fine to coarse-grained, brown. SANDY SILT (ML): fine to medium-grained sand, organics, black. 9/9/15 9/13/14 5/6/12 6/10/14 6 1 12 19 120 124 114 105 12-81-173-01 A-7 Drawing No. De p t h ( f t ) Checked By: Ground Surface Elevation (ft): Gr a p h i c Lo g CG Equipment: Project No. CME 75/ 8" HSA Log of Boring No. BH- 6 Logged by:Dates Drilled: NOT ENCOUNTERED Driving Weight and Drop:140 lbs / 30 in Depth to Water (ft): SUMMARY OF SUBSURFACE CONDITIONS 5/30/2012 This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.De p t h ( f t ) SM SAMPLES Gr a p h i c Lo g BU L K ±1127 SUMMARY OF SUBSURFACE CONDITIONS DR I V E BL O W S MO I S T U R E DR Y U N I T W T . (p c f ) OT H E R 5 10 15 Commercial And Multi-Family Development Planning Area 4; Approximately 43 Acre Site City of Temecula, Riverside County, California For: Cal-Paseo Del Sol, LLC Converse Consultants Project ID: 12-81-173-01.GPJ; Template: LOG End of boring at 16.5 feet. No groundwater encountered. Borehole backfilled loose with soil cuttings on 5/30/12. FILL: SILTY SAND (SM): fine to medium-grained, dark brown. ALLUVIUM (Qal): SILTY SAND (SM): fine to medium-grained, brown. 9/19/27 9/12/19 10/21/35 15/19/27 9 12 10 12 122 111 122 108 ds 12-81-173-01 A-8 Drawing No. De p t h ( f t ) Checked By: Ground Surface Elevation (ft): Gr a p h i c Lo g CG Equipment: Project No. CME 75/ 8" HSA Log of Boring No. BH- 7 Logged by:Dates Drilled: NOT ENCOUNTERED Driving Weight and Drop:140 lbs / 30 in Depth to Water (ft): SUMMARY OF SUBSURFACE CONDITIONS 5/30/2012 This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.De p t h ( f t ) SM SAMPLES Gr a p h i c Lo g BU L K ±1125 SUMMARY OF SUBSURFACE CONDITIONS DR I V E BL O W S MO I S T U R E DR Y U N I T W T . (p c f ) OT H E R 5 10 15 Commercial And Multi-Family Development Planning Area 4; Approximately 43 Acre Site City of Temecula, Riverside County, California For: Cal-Paseo Del Sol, LLC Converse Consultants Project ID: 12-81-173-01.GPJ; Template: LOG End of boring at 16.5 feet. No groundwater encountered. Borehole backfilled loose with soil cuttings on 5/30/12. FILL: SILTY SAND (SM): fine to coarse-grained, few silt, brown. CLAYEY SAND (SC): fine-grained, dark brown. ALLUVIUM (Qal): CLAYEY SAND (SC): fine-grained, some organics, dark brown. 15/17/21 5/9/20 6/8/11 9/13/19 5 19 15 18 111 103 102 111 ma,max ei 12-81-173-01 A-9 Drawing No. De p t h ( f t ) Checked By: Ground Surface Elevation (ft): Gr a p h i c Lo g CG Equipment: Project No. CME 75/ 8" HSA Log of Boring No. BH- 8 Logged by:Dates Drilled: NOT ENCOUNTERED Driving Weight and Drop:140 lbs / 30 in Depth to Water (ft): SUMMARY OF SUBSURFACE CONDITIONS 5/30/2012 This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.De p t h ( f t ) SM SAMPLES Gr a p h i c Lo g BU L K ±1124 SUMMARY OF SUBSURFACE CONDITIONS DR I V E BL O W S MO I S T U R E DR Y U N I T W T . (p c f ) OT H E R 5 10 15 Commercial And Multi-Family Development Planning Area 4; Approximately 43 Acre Site City of Temecula, Riverside County, California For: Cal-Paseo Del Sol, LLC Converse Consultants Project ID: 12-81-173-01.GPJ; Template: LOG End of boring at 16.5 feet. No groundwater encountered. Borehole backfilled loose with soil cuttings on 5/30/12. FILL: SILTY SAND (SM): fine to coarse-grained, brown. ALLUVIUM: SANDY SILT (ML): fine-grained sand, dark brown. SAND (SP): fine to coarse-grained, brown. 8/12/35 10/18/20 5/7/19 6/8/6 11 10 22 6 112 116 103 95 ca,er ma,r 12-81-173-01 A-10 Drawing No. De p t h ( f t ) Checked By: Ground Surface Elevation (ft): Gr a p h i c Lo g CG Equipment: Project No. CME 75/ 8" HSA Log of Boring No. BH- 9 Logged by:Dates Drilled: NOT ENCOUNTERED Driving Weight and Drop:140 lbs / 30 in Depth to Water (ft): SUMMARY OF SUBSURFACE CONDITIONS 5/30/2012 This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.De p t h ( f t ) SM SAMPLES Gr a p h i c Lo g BU L K ±1093 SUMMARY OF SUBSURFACE CONDITIONS DR I V E BL O W S MO I S T U R E DR Y U N I T W T . (p c f ) OT H E R 5 10 15 Commercial And Multi-Family Development Planning Area 4; Approximately 43 Acre Site City of Temecula, Riverside County, California For: Cal-Paseo Del Sol, LLC Converse Consultants Project ID: 12-81-173-01.GPJ; Template: LOG End of boring at 16.5 feet. No groundwater encountered. Borehole backfilled loose with soil cuttings on 5/30/12. FILL: SILTY SAND (SM): fine to coarse-grained, brown. SANDY SILT (ML): fine-grained sand, light brown. ALLUVIUM: SILTY SAND (SM): fine to coarse-grained, dark brown. SANDY SILT (ML): fine-grained sand, dark brown. 7/7/10 5/10/12 11/10/11 5/4/9 26 11 6 21 98 113 113 98 col ds 12-81-173-01 A-11 Drawing No. De p t h ( f t ) Checked By: Ground Surface Elevation (ft): Gr a p h i c Lo g CG Equipment: Project No. CME 75/ 8" HSA Log of Boring No. BH-10 Logged by:Dates Drilled: NOT ENCOUNTERED Driving Weight and Drop:140 lbs / 30 in Depth to Water (ft): SUMMARY OF SUBSURFACE CONDITIONS 5/30/2012 This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.De p t h ( f t ) SM SAMPLES Gr a p h i c Lo g BU L K ±1096 SUMMARY OF SUBSURFACE CONDITIONS DR I V E BL O W S MO I S T U R E DR Y U N I T W T . (p c f ) OT H E R 5 10 15 Commercial And Multi-Family Development Planning Area 4; Approximately 43 Acre Site City of Temecula, Riverside County, California For: Cal-Paseo Del Sol, LLC Converse Consultants Project ID: 12-81-173-01.GPJ; Template: LOG FILL: SILTY SAND (SM): fine to coarse-grained, light brown. ALLUVIUM: SILTY SAND (SM): fine to coarse-grained, light brown. SANDY SILT (ML): fine-grained sand, organics, dark brown. SILTY SAND (SM): fine to coarse-grained, brown. SANDY CLAY (CL): fine-grained sand, dark brown. SILTY SAND (SM): fine to coarse-grained, dark brown. 10/14/19 10/12/17 12/17/11 4/6/13 4/8/9 5/6/9 4/8/12 6 8 3 24 22 121 118 102 83 100 ma,max wa wa 12-81-173-01 A-12a Drawing No. De p t h ( f t ) Checked By: Ground Surface Elevation (ft): Gr a p h i c Lo g CG Equipment: Project No. CME 75/ 8" HSA Log of Boring No. BH-11 Logged by:Dates Drilled: 39.5 Driving Weight and Drop:140 lbs / 30 in Depth to Water (ft): SUMMARY OF SUBSURFACE CONDITIONS 5/30/2012 This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.De p t h ( f t ) SM SAMPLES Gr a p h i c Lo g BU L K ±1098 SUMMARY OF SUBSURFACE CONDITIONS DR I V E BL O W S MO I S T U R E DR Y U N I T W T . (p c f ) OT H E R 5 10 15 20 25 30 Commercial And Multi-Family Development Planning Area 4; Approximately 43 Acre Site City of Temecula, Riverside County, California For: Cal-Paseo Del Sol, LLC Converse Consultants Project ID: 12-81-173-01.GPJ; Template: LOG End of boring at 51.5 feet. Groundwater encountered at approximately 39.5 feet. Borehole backfilled loose with soil cuttings on 5/30/12. SILTY SAND (SM): fine to coarse-grained, some clay, dark brown. CLAYEY SAND (SC): fine to coarse-grained, brown. 3/9/31 22/32/35 13/15/26 20/30/36 18 22 114 106 12-81-173-01 A-12b Drawing No. De p t h ( f t ) Checked By: Ground Surface Elevation (ft): Gr a p h i c Lo g CG Equipment: Project No. CME 75/ 8" HSA Log of Boring No. BH-11 Logged by:Dates Drilled: 39.5 Driving Weight and Drop:140 lbs / 30 in Depth to Water (ft): SUMMARY OF SUBSURFACE CONDITIONS 5/30/2012 This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.De p t h ( f t ) SM SAMPLES Gr a p h i c Lo g BU L K ±1098 SUMMARY OF SUBSURFACE CONDITIONS DR I V E BL O W S MO I S T U R E DR Y U N I T W T . (p c f ) OT H E R 40 45 50 Commercial And Multi-Family Development Planning Area 4; Approximately 43 Acre Site City of Temecula, Riverside County, California For: Cal-Paseo Del Sol, LLC Converse Consultants Project ID: 12-81-173-01.GPJ; Template: LOG End of boring at 16.5 feet. No groundwater encountered. Borehole backfilled loose with soil cuttings on 5/30/12. FILL: SILTY SAND (SM): fine to coarse-grained, brown. ALLUVIUM: SANDY SILT (ML): fine to medium-grained sand, dark brown. SAND (SP): fine to coarse-grained, gray. 7/12/17 6/10/15 8/11/11 5/8/9 13 17 3 3 112 114 105 104 12-81-173-01 A-13 Drawing No. De p t h ( f t ) Checked By: Ground Surface Elevation (ft): Gr a p h i c Lo g CG Equipment: Project No. CME 75/ 8" HSA Log of Boring No. BH-12 Logged by:Dates Drilled: NOT ENCOUNTERED Driving Weight and Drop:140 lbs / 30 in Depth to Water (ft): SUMMARY OF SUBSURFACE CONDITIONS 5/30/2012 This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered.De p t h ( f t ) SM SAMPLES Gr a p h i c Lo g BU L K ±1094 SUMMARY OF SUBSURFACE CONDITIONS DR I V E BL O W S MO I S T U R E DR Y U N I T W T . (p c f ) OT H E R 5 10 15 Commercial And Multi-Family Development Planning Area 4; Approximately 43 Acre Site City of Temecula, Riverside County, California For: Cal-Paseo Del Sol, LLC Converse Consultants Project ID: 12-81-173-01.GPJ; Template: LOG GeoSoils, Inc. APPENDIX C 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 accordance with test methods ASTM designation D-1556, D-2937 or D-2922, and D-3017, GeoSoils, Inc. 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, alluvium, 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 or treated in a manner recommended by the geotechnical consultant. Soft, dry, spongy, Woodside 05S, LP Appendix C File:e:\wp21\murr\rc8500\8577a.gur Page 2 GeoSoils, Inc. 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 consultant. These materials should be free of roots, tree branches, other organic matter, Woodside 05S, LP Appendix C File:e:\wp21\murr\rc8500\8577a.gur Page 3 GeoSoils, Inc. 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. 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 Woodside 05S, LP Appendix C File:e:\wp21\murr\rc8500\8577a.gur Page 4 GeoSoils, Inc. 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 slopes, and extend out over the slope to provide adequate compaction to the face of the slope. Woodside 05S, LP Appendix C File:e:\wp21\murr\rc8500\8577a.gur Page 5 GeoSoils, Inc. 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 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. Woodside 05S, LP Appendix C File:e:\wp21\murr\rc8500\8577a.gur Page 6 GeoSoils, Inc. 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 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 Woodside 05S, LP Appendix C File:e:\wp21\murr\rc8500\8577a.gur Page 7 GeoSoils, Inc. 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 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. Woodside 05S, LP Appendix C File:e:\wp21\murr\rc8500\8577a.gur Page 8 GeoSoils, Inc. 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. 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. Woodside 05S, LP Appendix C File:e:\wp21\murr\rc8500\8577a.gur Page 9 GeoSoils, Inc. 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. 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 Woodside 05S, LP Appendix C File:e:\wp21\murr\rc8500\8577a.gur Page 10 GeoSoils, Inc. 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. 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, Woodside 05S, LP Appendix C File:e:\wp21\murr\rc8500\8577a.gur Page 11 GeoSoils, Inc. 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. 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 Woodside 05S, LP Appendix C File:e:\wp21\murr\rc8500\8577a.gur Page 12 GeoSoils, Inc. 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 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. Woodside 05S, LP Appendix C File:e:\wp21\murr\rc8500\8577a.gur Page 13 GeoSoils, Inc. 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. 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. Woodside 05S, LP Appendix C File:e:\wp21\murr\rc8500\8577a.gur Page 14