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Home My WebLink AboutCDP 08-13; Green Dragon Colonial Village; Preliminary Geotechnical Investigation; 2009-06-30PRELIMINARY GEOTECHNICAL INVESTIGATION PROPOSED GREEN DRAGON COLONIAL VILLAGE (FORMERLY HADLEY'S), PASEO DEL NORTE CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA FOR MR. BRUCE R. BARTLETT C/O ESBENSEN ARCHITECTURE 6150 YARROW DRIVE, SUITE H CARLSBAD, CALIFORNIA 92009 W.O. 5892-A-SC JUNE 30,2009 C*. ^ Geotechnical • Geologic • Coastal • Environmental 5741 Palmer Way • Carlsbad. California 92010 • (760)438-3155 • FAX (760) 931-0915 • www.geosoilsinc.com June 30, 2009 «- « « » . W.O. 5892-A-SC Mr. Bruce R. Bartlett c/o Esbensen Architecture 6150 Yarrow Drive, Suite H Carlsbad, California 92009 Attention: Mr. Dennis Moore Subject: Preliminary Geotechnical Investigation, Proposed Green Dragon Colonial Village (Formerly Hadley's). Paseo Del Norte, Carlsbad, San Diego County, California Dear Mr. Bartlett: In accordance with your request, GeoSoils. inc. (GSI) has performed a preliminary geotechnical evaluation of the subject site. The purpose of our investigation was to evaluate the geologic and geotechnical conditions of the site, relative to the proposed additional development, and to present recommendations for grading and foundation design, and construction criteria for the proposed development. EXECUTIVE SUMMARY Based on our review ofthe available data (see Appendix A), field exploration, laboratory testing, and geologic and engineering analysis, development ofthe property'appears to be feasible from a geotechnical viewpoint, provided the recommendations presented in the text ofthis report are properly incorporated into the design and construction ofthe project The most significant elements of this study are summarized below: Based on a review of the site development plan prepared by O'Day Consultants (2008), it is our understanding that the proposed development will consist of the construction of additional office/retail space to the existing structure, and improvement to the existing parking/driveway areas. In general, unsuitable surficial soils (i.e.. removals), consisting of existing fill and weathered formational sediments are on the order of 1 to 3 feet across a majority of the site. However, localized deeper removals cannot be precluded across the site. It should be noted that the California Building Code ([CBCJ, Califomia Building Standards Commission [CBSC], 2007), indicates mitigation be performed across all areas to be graded, not just within the influence of the structures. Relatively deep removals may also necessitate a special zone of consideration on perimeter/confining areas. This zone would be approximately equal to the depth of removals, if removals cannot be performed onsite to adjacent improvements, or offsite to same. Thus, any settlement-sensitive improvements (walls, curbs, flatwork, etc.), constructed within this limited removal zone, or where no removals are performed, may require deepened foundations, reinforcement, etc., or will retain some potential for settlement and associated distress. This will require proper disclosure to any interested/affected parties should this condition exist at the conclusion of grading. Maximum thickness of cuts and fills are anticipated to be on the order of about 5 feet, or less. Graded 2:1 (horizontal:vertical [h:v]) slopes are anticipated to be on the order of 5 feet, or less, in height, and are considered grossly and surficially stable, under normal conditions of care, maintenance, and rainfall. All slopes should be properiy constructed, as discussed in the "Genera! Earthwork, Grading Guidelines, and Preliminary Criteria" section ofthis report (see Appendix E). The expansion potential of tested onsite soils was evaluated to be low expansive, with a plasticity index (P.l.) of 20. As such, on a preliminary basis, site soils are considered to be expansive and should be designed and constructed in accordance with the minimum guidelines presented herein, and as presented in Chapter 18 (Section 1805A.8) ofthe CBC (CBSC, 2007). Thus, Code may require the use of more onerous foundations (i.e.. post-tension, mat, etc.). Final foundation design will be provided at the conclusion of grading the expansion and plasticity indices will need to be further evaluated at the conclusion of grading to confirm this preliminary foundation category. Post-tension slab foundations may also be used for these and all other soil conditions if desired. Alternatively, an imported blend of soil may be used to reduce the effects of expansive soils, and allow the use of a conventional foundation and slab system. Foundation systems should be minimally designed to accommodate a design differential settlement of at least 1 Inch in a 40-foot span, and 1 inch between dissimilarfoundation elements. These parameters are for static and seismic vertical deformation ofthe fill soil, and does not include seasonal fluctuations of expansive soils, which may increase this deformation. Sulfate testing indicates that site soils generally have a negligible exposure to concrete per the 2007 CBC. Corrosion testing (pH, resistivity) indicates that the soils are generally neutral (pH = 7.6), have a below threshold chloride content (70 ppm), and are mildly corrosive to ferrous metals. Alternative methods and additional comments should be obtained by a qualified corrosion engineer. Similar to expansive soils, the effects (i.e., distress) of corrosive soils occur over the lifetime of the project. These conditions should be revisited at the conclusion of grading, and disclosed to any other interested/affected parties. Mr. Bruce R. Bartlett ~~ W.O. 5892-A-SG File:e:\v/p9\5800\5892a.pgl Page Two Regional groundwater (near Mean Sea Level [MSL]) was not observed during the field investigation and is not expected to be a major factor in development of the site (lowest site elevation is on the order of 69 feet MSL). However, due to the nature ofthe site materials, seepage and/or perched groundwater conditions may develop throughout the site along boundaries of contrasting permeabilities (i.e., fill lifts or fill/bedrock contacts), may occur during or after development, and should be anticipated. This is especially true for any proposed fill-over-cut slopes, or shallow fills. This potential should be disclosed to any interested/affected parties. Our evaluation indicates that the site has a very low potential for liquefaction or seismic densification due to the dense nature of planned fill, the underiying sedimentary formation (considered "bedrock"), and the depth to the regional groundwater table. Therefore, no recommendations for mitigation are deemed necessary. Our evaluation indicates there are no known active faults crossing the site. The seismic acceleration values and design parameters provided herein should be considered during the design ofthe proposed development. The adverse effects of seismic shaking on the structure(s) will likely be wall/utility distress, with some foundation/slab distress, as well as associated seismic settlement. Code compliant projects are not intended to be earthquake proof, and may experience distress if subjected to the design earthquake. This potential should be disclosed to any Interested/affected parties. Adverse geologic features that would preclude project feasibility were not encountered, based on the available data. The recommendations presented In this report should be incorporated into the design and construction considerations of the project. Mr. Bruce R. Bartlett VV.O. 5892-A-SC File:e:\wp9VS800\5892a,pgi Page Three G-e&S&ilSf Inc. The opportunity to be of service is greatly appreciated. If you have any questions concerning this report: or if we may be of further assistance, please do not hesitate to contact any of the undersigned. Respectfully submitted, GeoSoils, Inc. Robert eTCrisman Engineering Geologisl RGC/ATG/JPF/jh Distribution: (4) Addressee /Andrew T. Guatelli Geotechical Engineer,' Mr. Bruce R. Bartlett Flle:e:\wp9\5800\5892a,pgi W.O. 5892-A-SC Page Four TABLE OF CONTENTS SCOPE OF SERVICES 1 SITE CONDITIONS/PROPOSED DEVELOPMENT 1 FIELD STUDIES 3 REGIONAL GEOLOGY 3 SITE GEOLOGIC UNITS 3 Artificial Fill (Map Symbol - Af) ............ 4 Quaternary-age Terrace Deposits (Map Symbol - Qt) [ [ [4 GROUNDWATER 4 FAULTING AND REGIONAL SEISMICITY 5 Regional Faults 5 Local Faulting 5 Seismicity 5 Seismic Hazards 7 Liquefaction 7 Other Hazards 7 Seismic Design Parameters 3 LABORATORY TESTING g Classification 9 Expansion Index 9 Atterberg Limits 9 Shear Testing 9 Resistance Value (R-value) 9 Sulfate/Corrosion Testing g PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS 10 PRELIMINARY EARTHWORK RECOMMENDATIONS 12 General Grading 12 Preliminary Earthwork Factors . '' 12 Demolition/Grubbing 13 Treatment of Existing Ground 13 Fill Suitability 14 Fill Placement -14 Transition Areas -14 Graded Slopes -| 5 PRELIMINARY FOUNDATION RECOMMENDATIONS 15 Conventional Foundations - Low Expansive (E.I. 20 to 50) 15 Foundation Design 15 Construction 16 Soil Moisture Considerations 18 WALKWAYS, FLATWORK, AND OTHER IMPROVEMENTS 19 PRELIMINARY PAVEMENT DESIGN 21 WALL DESIGN PARAMETERS CONSIDERING SITE SOILS 22 Conventional Retaining Walls 22 Restrained Walls 22 Cantilevered Walls 22 Retaining Wall Backfill and Drainage 23 Wall/Retaining Wall Footing Transitions 27 UTILITIES 27 DEVELOPMENT CRITERIA 28 Drainage 28 Erosion Control 28 Landscape Maintenance 28 Gutters and Downspouts 29 Subsurface and Surface Water 29 Site Improvements 29 Tile Flooring 30 Additional Grading 30 Footing Trench Excavation 30 Trenching/Temporary Construction Backcuts 30 Utility Trench Backfill 30 SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING 31 OTHER DESIGN PROFESSIONALS/CONSULTANTS 32 PLAN REVIEW 33 LIMITATIONS 33 Mr. Bruce R. Bartlett Table of Contents File:e:\wp9\5800\5892a.pgi Page ii FIGURES: Figure 1 - Site Location Map Figure 2 - California Fault Map f Detail 1 - Typical Retaining Wall Backfill and Drainage Detail24 Detail 2 - Retaining Wall Backfill and Subdrain Detail Geotextile Drain25 Detail 3 - Retaining Wall and Subdrain Detail Clean Sand Backfill 26 ATTACHMENTS: Appendix A - References D„_ r^fT Appendix B - Boring Logs Rea o TS Appendix C - EQFAULT. EQSEARCH, and FRISKSP .. Rea o TeS Appendix D - Laboratory Test Results Rear of Text Appendix E - General Earthwork and Grading Guidelines Rear of Text Plate 1 - Geotechnical Map ' pjgg^ of Text in Folder Mr. Bruce R. Bartlett ~~ ~~ ~~ Frle:e:\wp9\5800\5892a.pgi ' °f Contents Page iii Ce&S&itSf Ine, PREUMINARY GEOTECHNICAL INVESTIGATION PROPOSED GREEN DRAGON COLONIAL VIUAGE (FORMERLY HADLEY'S), PASEO DEL NORTE CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA SCOPE OF SERVICES The scope of our services has included the following: 1. Review of the available geologic literature for the site (Appendix A). 2. Subsurface exploration consisting ofthe excavation of three (3) hand auger borings, for the purpose of evaluating subsurface conditions, geologic structure, and to facilitate soil sampling (Appendix B). 3. Evaluation of regional seismicity (Appendix C). 4. Pertinent laboratory testing of representative soil samples collected during our subsurface exploration program (Appendix D). 5. Engineering and geologic evaluation. 6. Appropriate engineering and geologic analysis of data collected and preparation ofthis report, including earthwork and foundation design/construction. This report does not address existing or potential environmental concerns relative to the subject property. SITE CONDITIONS/PROPOSED DEVELOPMENT The subject site consists of an irregulariy-shaped approximately 3-acre parcel, located west of Paseo Del Norte, East of Interstate 5, and south and north of existing commercial properiy, In the City of Carlsbad, California (Figure 1). Topographically, the site consists of a relatively fiat-lying pad area with a large (25-foot high) graded slope descending from the building area to the Interstate 5. Existing improvements onsite consist of paved (asphalt) parking areas and an existing, single-story commercial building structure (formerly Hadley's Market). Drainage appears to be directed oflfsite to the north and south. Based on our review of the referenced plan, it is our understanding that proposed development consists of an extensive remodel to the existing commercial structure, and a re-deslgned/new parking/driveway area. Plans also indicate that some grading witl be performed as part of the parking area improvement. Cuts and fills on the order of 5 feet, or less are planned. Building loads are assumed to be typical for this type of structure. Base Map: TOPOl® ©2003 National Geographic, U.S.G.S San Luis Rey Quadrangle, California -- San Diego Co., 7.5 Minute, dated 1997, current, 1999. 0 im 2000 3000 4000 ... -. - . _ Base Map: The Thomas Guide, San Diego Co., Street Guide and Directory, 2005 Edition, by Thomas Bros. Maps, page 1126. ALL LOCATIONS ARE APPROXIMATE Reproduced with permission gronted by Thomas Bros. Mops This map is copyrighted by Thomas Bros. Maps. It is unlawful io copy or reproduce all or any part thereof, whether for personal use or resale, withoui permission. All rtghts reserved. GeoSoilsll^c. W.O. 5892-A-SC SITE LOCATION MAP Figure 1 FIELD STUDIES Field studies conducted during our evaluation of the property for this study consisted of geologic reconnaissance mapping, and excavation of three (3) exploratory borings with a truck mounted, hollow stem auger drill rig to evaluate near-surface soii and geologic conditions. The borings were logged by a engineering geologist from our firm who collected representative bulk samples for appropriate laboratory testing. The logs of the borings are presented in Appendix B. The approximate locations of the borings are presented on Plate 1. Plate 1 has been adapted from a site development plan provided by the project civil engineer (O'Day, 2008). REGIONAL GEOLOGY The subject property is located within a prominent natural geomorphic province in southwestern California known as the Peninsular Ranges. It is characterized by steep, elongated mountain ranges and valleys thattrend northwesteriy. The mountain ranges are underlain by basement rocks consisting of pre-Cretaceous metasedimentary rocks, Jurassic metavolcanic rocks, and Cretaceous plutonic rocks of the southern California batholith. In the San Diego County region, deposition occurred during the Cretaceous Period and Cenozoic Era in the continental margin of a forearc basin. Sediments, derived from Cretaceous-age plutonic rocks and Jurassic-age volcanic rocks, were deposited into the narrow, steep, coastal plain and continental margin ofthe basin during the Eocene. These rocks have been uplifted, eroded, and deeply incised. During early Pleistocene time, a broad coastal plain was developed from the deposition of marine terrace deposits. During mid-to late-Pleistocene time, this plain was uplifted, eroded, and incised. Alluvial deposits have since filled the lower valleys, and young marine sediments are currently being deposited/eroded within coastal and beach areas. Based on our field work and review, the site appears to be underlain by Quaternary-age terrace deposits (Eisenberg, 1983; Tan and Kennedy, 1996). SITE GEOLOGIC UNITS The site geologic units encountered during site reconnaissance and subsurface investigation included existing fill, colluvium, and underiying formational sediments (terrace deposits). The earth materials are generally described below from the youngest to the oldest. Mr. Bruce R. Bartlett W.O. b892-A-SC Green Dragon Colonial Village, Carlsbad June 30, 2009 Rle:e:\wp9\5800\5892a.pgi Page 3 Artificial Fiii (Map Symbol - Af) Artificial fill onsite consists of a surficial layer of soil varying from silty sand to sandy clay probably placed during original site development in the 1970's. Where observed these matenals were on the order of 1 to 3 feet thick and are typically dry to wet, loose/soft and porous. These soils are non-uniform and are considered potentially compressible in'their existing state. Thus, they will require removal during excavation within the site if settlement-sensitive structures are proposed within their influence. Quaternarv-aae Terrace Deposits (Map Symbol - Qt) Formational soils, consisting of Quaternary-age terrace deposits underlie the site As encountered, terrace deposits consist of interbedded sand, silty sand and sandy clay These sediments are generally various shades of brown, damp to moist and medium dense to dense/stiff to very stiff. These formational soils are considered suitable for the support of engineered fills and planned improvements. Field mapping from this study indicates that terrace deposits are thickly bedded (massive), to weakly bedded in a generally flat-lying regional trend. GROUNDWATER A perched groundwater table was encountered at a depth of approximately 31 feet (elevation of approximately 43 feet Mean Sea Level [MSL]). Our review indicates that regional groundwater occurs at depths near sea level, approximately 74 feet below the site and IS not anticipated to adversely affect planned site development, provided that the recommendations contained in this report are incorporated into final design and construction. These obsen/ations reflect site conditions at the time of our Investigation and do not preclude future changes in local groundwater conditions from excessive irrigation precipitation, or that were not obvious, at the time of our investigation Perched groundwater conditions along fill/bedrock contacts, and along zones at contrasting permeabilities (i.e., fill lifts, discontinuities, etc.), may not be precluded ft-om occurring in the future due to site irrigation, poor drainage conditions (onsite or offsite) or damaged utilities, and should be anticipated. Thus, more onerous slab design'for moisture mitigation is warranted. Should perched groundwater conditions develop this office could assess the affected area(s) and provide the appropriate recommendations to mitigate the observed groundwater conditions. This potential should be disclosed to anv interested/affected parties. Mr. Bruce R. Bartlett — WO -^flQP A qr F?" ?58o:s?9fJune 3o1o09 File;e:\wp9\5800\589?a pqi Page 4 ^0SmlSy ine. I I FAULTING AND REGIONAL SEISMICITY Reqionai Faults Our review indicates that there are no known active faults crossing this site within the area proposed for development, and the site is not within an Alquist-Priolo Earthquake Fault Zone (Bryant and Hart, 2007). However, the site is situated in an area of active, as well as potentially active, faulting. These include, but are not limited to: the San Andreas fault; the San Jacinto fault; the Elsinore fault; the Coronado Bank fault zone; and the Newport-lnglewood-Rose Canyon fault zone. The location of these and other major faults relative to the site are indicated on Figure 2 (California Fault Map). The possibility of ground acceleration or shaking at the site may be considered as approximately similar to the southern California region as a whole. Major active fault zones that may have a significant altect on the site should they experience activity are listed in Appendix C (modified from Blake, 2000a). Local Faulting No local faulting was observed to transect the site during the field investigation. Additionally, a review of regional geologic maps (Eisenberg, 1983; Tan and Kennedy, 1996) does not indicate the presence of local faults crossing the site. Seismicity The acceleration-attenuation relations of Bozorgnia, Campbell, and Niazi (1999) and Campbell and Bozorgnia (1994 and1997) have been incorporated into EQFAULT (Blake, 2000a). EQFAULT is a computer program developed by Thomas F. Blake (2000a), which performs deterministic seismic hazard analyses using digitized California faults as earthquake sources. The program estimates the closest distance between each fault and a given site. If a fault is found to be within a user-selected radius, the program estimates peak horizontal ground acceleration that may occur at the site from an upper bound ("maximum credible") earthquake on that fault. Site acceleration (g) is computed by one or more user-selected acceleration-attenuation relations that are contained in EQFAULT. Based on the EQFAULT program, peak horizontal ground accelerations from an upper bound event at the site may be on the order of 0.66g. The computer printouts of pertinent portions ofthe EQFAULT program are included within Appendix C. Historical site seismicity was evaluated with the acceleration-attenuation relations of Campbell and Bozorgnia (1994 and 1997), and the computer program EQSEARCH (Blake, 2000b). This program performs a search of the historical earthquake records for magnitude 5.0 to 9.0 seismic events within a 100-kilometer radius, between the years Mr. Bruce R. Bartlett W.O. 5892-A-SC Green Dragon Colonial Village, Carlsbad June 30, 2009 Fite:e:\v/p9\5800\5892a.pgi Page 5 1100 1000 900 800 -- 700 -- 600 500 -- 400 — 300 200 100 0 -- CALIFORNIA FAULT MAP GREEN DRAGON/BARTLET •100 -400 -300 -200 -100 0 100 200 300 400 500 600 W.O. 5892-A-SC Figure 2 Oe&SoiUf Ine, 1800 through December 2008. Based on the selected acceleration-attenuation relationship, a peak horizontal ground acceleration is estimated, which may have efl^ected the site during the specific event listed. Based on the available data and the attenuation relationship used, the estimated maximum (peak) site acceleration during the period 1800 through December 2008 was 0.32 g. A historic earthquake epicenter map and a seismic recurrence curve are also estimated/generated ft-om the historical data. Computer printouts ofthe EQSEARCH program are presented In Appendix C. A probabilistic seismic hazards analyses was performed using FRISKSP (Blake, 2000c), which models earthquake sources as 3-dimensional planes and evaluates the site specific probabilities of exceedance for given peak acceleration levels or pseudo-relative velocity levels. Based on a review ofthis data, and considering the relative seismic activity ofthe southern California region, a peak horizontal ground acceleration of 0.20 g was calculated. This value was chosen as it corresponds to a 10 percent probability of exceedance in 50 years (or a 475-year return period). Computer printouts of the FRISKSP program are included in Appendix C. Seismic Hazards The following list includes other seismic related hazards that have been considered during our evaluation ofthe site. The hazards listed are considered negligible and/or completely mitigated as a result of site location, soil characteristics, and typical site development procedures: Liquefaction Given the presence of interbedded fine grained soils, the overall density ofthe underlying formational sediments (bedrock), and the depth to regional groundwater (i.e., greaterthan 50 feet), the potential for damaging deformations due to soil liquefaction is considered low. Other Hazards The following list includes other seismic related hazards that have been considered during our evaluation of the site. The hazards listed are considered negligible and/or mitigated as a result of site location, soil characteristics, and typical site development procedures: Dynamic Settlement (Densification) Surface Fault Rupture Ground Lurching or Shallow Ground Rupture Tsunami It is important to keep in perspective that in the event of a "maximum probable" or "upper bound" (maximum credible) earthquake occurring on any of the nearby major faults, strong ground shaking would occur In the subject site's general area. Potential Mr. Bruce R. Bartlett W.O. 5892-A-SC Green Dragon Colonial Village, Carlsbad June 30, 2009 File:e;\wp9\5800\5892a.pgi Page 7 Ge€fBmt§f Ine, damage to any structure(s) would likely be greatest from the vibrations and impelling force caused by the inertia of a structure's mass than from those induced by the hazards considered above. This potential would be no greater than that for other existinq stmctures and improvements in the immediate vicinity. Seismic Design Parameters The table below summarizes the site-specific design criteria per the Califomia Buildinq Code ([CBC], California Building Standards Commission [CBSC] 2007) The computer program Seismic Hazard Curves and Uniform Hazard Response Spectra, provided by the U.S.G.S aided in the evaluation of these parameters. The short spectral response uses a penod of 0.2 seconds. 1 PARAMETER VALUE CBC REFERENCE Site Class D Table 1613.5.2 Spectral Response - (0.2 sec), 1.299g Figure 1613.5(3) Spectral Response - (1 sec), S, 0.491 g Figure 1613.5(4) Site Coefficient, 1.00 Table 1613.5.3(1) Site Coefficient, F^ 1.509 Table 1613.5.3(2) Maximum Considered Earthquake Spectral Response Acceleration (0.2 sec), S^g 1.299g Section 1613.5.3 (Eqn 16-37) Maximum Considered Earthquake Spectral Response Acceleration (1 sec), S^,, 0.740g Section 1613.5.3 (Eqn 16-38) 5% Damped Design Spectral Response Acceleration (0.2 sec), S^g 0.866g Section 1613.5.4 (Eqn 16-39) 5% Damped Design Spectral Response Acceleration (1 sec), S^, 0.494g Section 1613.5.4 (Eqn 16-40) Conformance to the criteria above for seismic design does not constitute any kind of guarantee or assurance that significant sft-uctural damage or ground failure will not occur in the event of a large earthquake. The primary goal of seismic design is to protect life not to eliminate all damage, since such design may be economically prohibitive Cumulative effects of low order or non-design seismic events can increase the level of damage onsite If mitigation and repairs are not made after each significant seismic event Mr. Bruce R, Bartlett Green Dragon Colonial Village, Carlsbad File:e:\wp9\5800\5892a.pgi W.O. 5892-A-SC June 30, 2009 Page 8 G-e&S&Us, Ine, LABORATORY TESTING Classification The soils were classified visually by GSI during our site investigation according to the Unified Soils Classification System, in accordance with ASTM D 2487, D 2488, and by supplemental index testing, as warranted. The soil classifications are shown on the Hand Auger Boring Logs (Appendix B). Expansion Index Expansion Index (E.I.) testing was performed on a representative soil sample, in general accordance with ASTM 4829. The test results are presented below as well as the expansion classification according to CBC (CBSC, 2007). LOCATION B-2 @ 1-2' SOIL TYPE SANDY CLAY, Brown EXPANSION INDEX 41 * Based on the 2001 CBC Classification El = 21-50 is low. Atterberg Limits EXPANSION POTENTIAL Low* Tests were performed on representative soils to evaluate the liquid limit, plastic limit, and plasticity index (P.l.) in general accordance with ASTM D 4318. The test results indicate that the onsite soils are plastic. Test results are presented in Appendix C. Shear Testing Shear testing was performed on a representative, undisturbed sample of site soil in general accordance with ASTM Test Method D-3080 in a direct shear machine ofthe strain control type. The shear test results are presented in Appendix D. Resistance Value (R-value) Resistance value (R-value) testing was performed on a representative sample of site soil (clay) in general accordance with Cal Test 301. An R-value of 66 was evaluated for these soils conditions (see Appendix D). Sulfate/Corrosion Testing GSI conducted sampling of onsite materials for soil corrosivity on the subject project. Laboratory test results were completed by Prime Testing, Inc. (consulting corrosion Mr. Bruce R. Bartlett W.O. 5892-A-SC Green Dragon Colonial Village, Carlsbad June 30, 2009 File:e:\wp9\5800\5892a.pgi Page 9 Ge&SoUs, Ine, engineers). The testing included evaluation of pH, soluble sulfates and saturated resistivity. Sulfate testing indicates that site soils generally have a negligible exposure to concrete per the 2007 CBC (sample = 0.036 percent by weight). Corrosion testing (pH, resistivity) indicates that the soils are generally neuft-al (pH = 7.6), and are corrosive to ferrous metals (saturated resistivity = 590 ohms-cm). Chloride test results indicate that chloride content, as received, was 70 mg/km (milligrams per kilograms [parts per million] of dry soil) Test results are presented in Appendix D. Alternative methods and additional comments should be obtained by a qualified corrosion engineer. Similar to expansive soils, the effects (i.e., distress) of corrosive soils occur over the lifetime ofthe project. This potential should be disclosed to any interested/affected parties. PRELIMINARY CONCLUSIONS AND RECOMMENDATION.q Based on our field exploration, laboratory testing, and our engineering and geologic analyses. It is our opinion that the project site appears suited for the proposed use from a geotechnical viewpoint, provided that the recommendations presented herein are incorporated into the design and construction phases of site development. The primary geotechnical concerns with respect to the proposed development are: Earth materials characteristics and depth to competent bearing material. Differential performance between proposed and existing structures, including settlement, and design life. On-going expansion and corrosion potential of site soils. Subsurface water and potential for perched water to occur during grading and after development. Non-structural zone on unmitigated perimeter conditions (proposed settlement-sensitive improvements may be subject to distress). 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 during our field work. In the event that any significant changes are made to proposed site development the conclusions and recommendations contained in this report shall not be considered valid Mr. Bruce R. Bartlett " WO 5892-A-SC Green Dragon Colonial Village, Carlsbad ju^g gg 2009 File:e:\wp9\5800\5892a.pgi p^^^ d^oSoils, Ine, 1. unless the changes are reviewed and the recommendations of this report evaluated 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. Soil engineering, observation, and testing sen/ices should be provided during grading to aid the contractor in removing unsuitable soils and in this effort to compact the fill. 2. Geologic observations should be performed during grading to further evaluate geologic conditions. Although unlikely, if adverse geologic structures are encountered, supplemental recommendations and earthwork may be warranted. 3. Existing flll, and any weathered formational soil (if present), observed to depths on the order of ±3 feet are considered unsuitable in their current condition for the support of settlement-sensitive structures in their present condition, based on current industry standards. Onsite fill soils may be re-used as compacted fill, provided these materials are removed and recompacted as engineered fill. 4. In general and based upon the available data to date, regional groundwater is not expected to be a significant factor In development of the site. However, due to the nature of the site materials, seepage due primarily to irrigation will likely occur throughout the site (at fill/bedrock contacts or in or within shallow fills) along with seasonal perched water within any drainage areas, during and after development. 5. General Earthwork, Grading Guidelines, and Preliminary Criteria are provided atthe end of this report as Appendix E. Specific recommendations are provided below. 6. Our laboratory test results and experience on nearby sites related to expansion potential indicate that soils generally with a low, to possibly medium expansion potential underlie the site. The foundation recommendations presented herein are considered as minimum from a geotechnical standpoint. Asthe soils are expansive. desian and construction should also be minimally desicned in accordance with Chapter 18 (Section 1805A.8) ofthe CBC (CBSC. 2007). This implies that the Code may require the use of more onerous foundations (i.e., post-tension, mat, etc.). This should be considered during project design, as final foundation design will be provided at the conclusion of grading. Foundation design and construction recommendations are provided herein for these soil conditions. Alternatively, a blend of onsite soils and import may be employed in the development to reduce the code requirements for foundations. 7. The seismic induced acceleration values and code coefficients provided herein should be considered during the design of the proposed development. Some seismic Induced densification of fil! soils should be anticipated and considered during design. Mr. Bruce R, Bartlett W.O. 5892-A-SC Green Dragon Colonial Village, Carlsbad june 30, 2009 File:e:\wp9\5800\5892a.pgi Page 11 &e®S@MSf Ine, PRELIMINARY EARTHWORK RECOMMENDATIONS General Grading All grading should conform to the guidelines presented in the CBC (CBSC 2007) the County, and Appendix E (this report), except where specifically superceded in the text of this report. When code references are not equivalent, the more stringent code should be followed. Dunng earthwork construction, all site preparation and the general grading procedures of the contractor should be observed and the fill selectively tested by a representative(s) of GSI. If unusual or unexpected conditions are exposed in the field they should be reviewed by this office and if warranted, modified and/or additional recommendations will be offered. All applicable requirements of local and national construction and general industry safety orders, the Occupational Safety and Heatth Act, and the Construction Safety Act should be met. GSI does not consuft in the area of safety engineering. The contractor Is responsible for the safety of construction workers onsite. Preliminarv Earthworlc Factors Preliminary earthwork factors (shrinkage and bulking) forthe subject property have been estimated based upon our fleld and laboratory testing, visual site obsen/ations and expenence on surrounding properties, tt is apparent that shrinkage would vary with depth and with areal extent over the site based on previous site use. Variables include vegetation, weed control, discing, and previous fllling or exploring. The removal of existing foundations, utilities, or other buried substructures or improvements will increase the volume of need fill to create the planned grade(s). Therefore, the information presented below represents average shrinkage/bulking values using certain earthwork assumptions as follows: MATERIAL SHRINKAGE/BULKING Existing Fill 3 to 8 percent (shrinkage) Terrace Deposits 0 to 5 percent (shrinkage) An additional shrinkage factor item would include the removal of root systems of individual large plants or trees. These plants and trees vary in size, but when pulled they may generally resutt in a loss of Ye to 1 Vz cubic feet, to locally greater than 1 Vz cubic yards of volume, respectively. This factor needs to be muttiplied by the number of significant plants, trees, or tree roots present to evaluate the net loss. Any roots remaining in the fill will likely require "picking" and will further reduce the available fill volume Subsidence in Mr. Bruce R. Bartlett Green Dragon Colonial Viiiage, Carlsbad File:e:\wp9\5800\5892a.pgi W.O. 5892-A-SC June 30, 2009 Page 12 GeoSoUs^ Ine, the bedrock areas is anticipated to be nil. Further, methods employed by the grading contractor may effect these values, above, by up to about 4 percent. The above facts indicate that earthwork balance for the site would be difficutt to define and flexibility in design is essential to achieve a balanced end product. Demolition/Grubbing 1. Vegetation and any miscellaneous debris should be removed from the areas of proposed grading. 2. Any existing subsurface structures uncovered during the recommended removal should be observed by GSI so that appropriate remedial recommendations can be provided. 3. Cavities or loose soils remaining after demolition and site clearance should be cleaned out and observed by the soil engineer. The cavities should be replaced with fill materiais that have been moisture condrtioned to at least optimum moisture content and compacted to at least 90 percent ofthe laboratory standard. 4. Onsite septic systems (if encountered) should be removed in accordance with San Diego County Department of Environmental Health standards/guidelines. Treatment of Existinq Ground 1. All existing flll, and surficial weathered formational soil (if present) should be removed to suitable bedrock, cleaned of deleterious materials, moisture conditioned, and recompacted if not removed by proposed excavation wrthin areas proposed for settlement-sensitive improvements. Thicknesses of these materials are discussed in eariier sections ofthis report. Variations from these thicknesses should be anticipated. At this time, removal depths across the site, on the order of 1 to 3 feet, should be anticipated; however, locally deeper removals may be necessary. Actual depths of removals will be evaluated in the field during grading by the geotechnical consultant. 2. Subsequent to the above removals, the upper 8 inches of the exposed subsoils/bedrock should be scarified, broughtto atjeast optimum moisture content, and recompacted to a minimum relative compaction of 90 percent ofthe laboratory standard, prior to any fill placement. 3. Existing fill and formational soil may be reused as compacted fill provided that major concentrations of vegetation and miscellaneous debris are removed from the site, prior to or during fill placement. Mr. Bruce R. Bartlett W.O. 5892-A-SC Green Dragon Colonial Village, Carlsbad June 30, 2009 File;e;\wp9\5800\5892a.pgi Page 13 QeoSmlSf Ine, 4. Localized deeper removals may be necessary due to buried drainage channel meanders or dry porous materials, septic systems, etc. The project soils engineer/geologist should observe all removal areas during the grading. Fill Suitability Existing earth materials onsite should generate good quality fill material. Oversize material (i.e., greater than 12 inches in long dimension) is not anticipated. If soil importation is planned, samples ofthe soil import should be evaluated by this ofllce prior to importing in order to assure compatibility wrth the onsite site soils and the recommendations presented in this report. Import soils should be relatively sandy and low expansive (i.e., E.I. <50, and have a PI < 15). Fill Placement 1. Subsequent to ground preparation, fill materials should be brought to at least 1 to 2 percent above optimum moisture content, 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. Fill materials should be cleansed of major vegetation and debris prior to placement. 3. Any import materials should be observed and deemed 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 encountered in this investigation. Transition Areas In order to partially mitigate the potential for perched groundwater, and provide for the uniform support of the proposed settlement-sensitive improvements, a minimum 3-foot thick compacted fill blanket is recommended if the building pad contains earth material transitions (i.e., fill juxtaposed against bedrock), as discussed herein. Any cut portion of a transition lot with planned fills less than 3 feet should also be overexcavated a minimum 3 feet below finish pad grade In order to provide for a minimum 3-foot compacted fill blanket, or 24 inches of compacted fill beneath the planned footings, whichever Is greater. Cut portions should also be overexcavated 3 feet in all areas proposed for settlement-sensitive improvements. The maximum to minimum fill thickness, below settlement-sensitive improvements, should not exceed a ratio of 3:1 (maximum:minimum), and should slope to the street. The overexcavation should be completed per code, or to a minimum of 5 feet outside the building footprint and/or settlement-sensrtive improvements, whichever is more onerous. Slot cuts near existing buildings may be warranted during excavation for proposed additions/buildings. Cut areas will have an increased potential for perched water to occur after development; therefore, the removal bottom should be sloped to drain to a subdrain or other suitable area. Mr. Bruce R. Bartlett W.O. 5892-A SC Green Dragon Colonial Village, Carlsbad june 30 2009 File:e:\v/p9\5800\5892s.pgl Page 14 CeeS&Us, Ine, Graded Slopes Based on our slope stability evaluation and experience on nearby projects, proposed cut slopes constructed utilizing onsite materials, to the heights proposed, should be grossly and surficially stable provided the recommendations contained herein are properly implemented during site development, under normal conditions of care, maintenance, and rainfall. All graded slopes, backcuts, etc., should be mapped by the project engineering geologist during grading to allow amendments to the recommendations should exposed conditions warrant alteration ofthe design or stabilization. The cut portion of any proposed fill-over-cut slopes should be excavated first, in order to evaluate the suitability of tiie proposed cut slope, priorto placing fill on top ofthe cut slope. If stabilization fills are warranted, keyways and subdrains, as indicated in Appendix E, will be recommended, as necessary. PRELIMINARY FOUNDATION RECOMMENDATIONS The foundation design and construction recommendations are based on laboratory testing and engineering evaluations of onsite earth materials by GSI. Proposed new and existing foundations will settle and perform differently. This potential will need to be accounted for in design. Othenwise, a construction joint wil! need to be maintained between new and existing foundations, and the superjacent structures to permrt relative movement between these two elements. The following preliminary foundation construction recommendations are presented as a minimum criteria from a soils engineering viewpoint. The onsite soils expansion potentials are generally in the low (E.I. 21 to 50) range, with a plasticity index of 20. For these expansive soil conditions (E.I. >20 and < 50), and where the P.l. is greater than 15, code-compliant foundations will be needed, designed in accordance with Chapter 18 (Section 1805A.8) of the CBC (CBSC, 2007). Thus, Code may require the use of more onerous foundations (i.e., post-tension, mat, etc.). Final foundation design will be provided at the conclusion of grading. Alternatively, a blend of onsite soils and import may be employed in the development to reduce the code requirements for foundations. Conventional Foundations - Low Expansive (E.I. 20 to 50) The following foundation construction recommendations assume that the soils in the top 7 feet from finish grade will have a low expansion potential. Recommendations by the project's design-structural engineer or architect, which may exceed the soils engineer's recommendations, should take precedence over the following minimum requirements. Foundation Design Conventional spread and continuous footings may be used to support the proposed residential structure, provided they are founded entirely in properiy compacted fill or other competent bearing material. Mr. Bruce R. Bartlett W.O. 5892-A-SC Green Dragon Colonial Viiiage, Carlsbad june 30 2009 File:e:\wp9\5800\5892a.pgi Page 15 Gm&SmlSf Ine, 1. An allowable bearing value of 1,500 pounds per square foot (psf) may be used for design of footings which maintain a minimum widtli of 12 inches (continuous) and 24 inches square (isolated), and a minimum depth of at least 12 inches into the properiy compacted fill or formation (terrace deposits). The bearing value may be increased by one third for seismic or other temporary loads. This value may be increased by 20 percent for each additional 12 inches in depth to a maximum of 2,500 psf. No increase in bearing value for increased footing width is recommended. The bearing value and elevation of the bearing surface should be compatible with the existing foundations. 2. For lateral sliding resistance, a 0.35 coefficient of friction may be utilized for a concrete to soil contact when multiplied by the dead load. 3. Passive e^h pressure may be computed as an equivalent fluid having a density of 250 pounds per cubic foot (pcf) with a maximum earth pressure of 2,500 psf. 4. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. 5. Foundations should be designed to minimally accommodate a differential settlement of 1 inch in a 40-foot span, and 1 inch between dissimilar foundation elements. 6. All footings should maintain a minimum 7-foot horizontal distance between the base of the footing and any adjacent descending slope, and minimally comply with the guidelines presented in the CBC (CBSC, 2007). 7. Site soils are expansive, as such foundations shall also be designed in accordance with Chapter 18 (Section 1805A.8) ofthe CBC (CBSC, 2007). This implies that the Code may require the use of more onerous foundations (i.e., post-tension, mat, etc.). 8. Code-compliant foundations may be conventional-type ifthe grading and blending of low expansive soils onsite produces a fill with an El < 50, and a PI < 15. Construction 1. Continuous perimeter or interior strip footings should be founded at a minimum depth of 12 inches and 18 inches below the lowest adjacent ground surface, for one- and two-story loads, respectively. Interior footings may be founded at a depth of 12 inches below the lowest adjacent ground surface, into either suitable formational soil, or properiy compacted fill. Existing flll is not recommended for the support of any concrete floor slabs-on-grade or settlement-sensrtive improvements. Mr. Bruce R. Bartlett W.O. 5892-A-SC Green Dragon Colonial Village, Carlsbad June 30, 2009 FHe:e;Vwp9\5800\5892a.pgi Page 16 GeoSoits, Ine, Footings for one- and two-story floor loads should have a minimum width of 12 inches and 15 inches, respectively. All footings should have two No. 4 reinforcing bars placed at the top and two No. 4 reinforcing bar placed at the bottom of the footing. Isolated interior or exterior piers and columns should be founded at a minimum depth of 18 inches below the lowest adjacent ground surface (excluding slab underfayment and/or landscape zone [top 6 inches]). Inasmuch as low expansive soils are present witiiin the top 7 feet, these elements should be tied together with a grade beam. 2. A grade beam, reinforced as above and at least 12 inches square, should be provided across large entrances. The base ofthe reinforced grade beam should be at the same elevation as the adjoining footings. 3. Concrete slabs should be underiain with a minimum 4 inches of clean sand. Sand used for slab underiayment should have a minimum sand equivalent (S.E.) of 30. A vapor retarder shall be placed near the vertical midpoint of the sand layer. The slab designer should review the "Soil Moisture Considerations" section for further recommendations with regard to moisture transmission and slab underiayment. 4. Concrete slabs, should be a minimum of 5 inches thick, and minimally reinforced with No. 3 reinforcement bars placed on 18-inch centers, in two horizontally perpendicular directions (i.e., long axis and short axis). All slab reinforcement should be supported to provide proper mid-slab height posrtioning during placement ofthe concrete. "Hooking" of reinforcement is not an acceptable method of positioning. 5. In order to mitigate the potential for water vapor transmission through the slab, and to comply with minimum State requirements (State of California, 2009), the water/cement ratio of the concrete should be 0.5, or less, othenwise associated water vapor and water vapor transmission may increase the potential for distress to moisture-sensitive coverings or improvements. 6. The slab subgrade should be free of loose and uncompacted material prior to placing concrete. 7. Presoaking of slab subgrade(s) is necessary for these expansive soil conditions. The moisture content of the subgrade soils should be equal to or greater than optimum moisture to a depth of 12 inches below the adjacent ground grade in the slab areas, and verified by this office within 72 hours of the vapor retarder placement. 8. As an attemative to an expansive soil-resistant slab, an engineered post-tension foundation system may be used. Recommendations for post-tension slab design may be provided on request. Mr. Bruce R. Bartlett W.O. 5892-A-SC Green Dragon Colonial Village, Carlsbad june 30, 2009 Rle:e:\wp9\5B00V5892a.pgl Page 17 &eoSoilSf Ine, 9. Soils generated from footing excavations to be used onsite should be compacted to a minimum relative compaction 90 percent of the laboratory standard, whether rt is to be placed inside the foundation perimeter or in the yard/right-of-way areas. This material must not alter posrtive drainage patterns that direct drainage away from the structural areas and toward the street. 10. Foundations near the top of slope should be deepened to conform to the latest edrtion of the CBC (CBSC, 2007) and provide a minimum of H/3 (where H is the height of the adjacent slope), and not less than 7 feet horizontal distance from the slope face. Rigid block wall designs located along the top of slope should be reviewed by a geotechnical consultant. Soil Moisture Considerations GSI has evaluated the potential for vapor or water transmission through the slabs, in light of typical residential floor coverings and improvements. Typical slab moisture emission rates range from about 2 to 27 Ibs./1,000 square feet from a typical slab (Kanare, 2005), while most floor covering manufacturers recommend about 3 lbs./24 hours as an upper limit Thus, the client will need to evaluate the following in light of a cost versus benefrt analysis (tenant complaints and repairs/replacement), along with disclosure to owners. Considering the E.I. test results, anticipated typical water vapor transmission rates, and floor coverings and improvements (to be chosen bythe client) that can tolerate those rates wrthout distress, the following altematives are provided: Concrete slabs should be a minimum of 5 inches thick. Concrete slab underlayment should consist of a 10-mil vapor retarder, or equivalent, with all laps sealed per the CBC (CBSC, 2007) and the manufacturer's recommendation. The vapor retarder should comply with the ASTM E1745 - Class A or B criteria, and be instailed in accordance with ACI 302.1 R-04. The 10-to 15-mil vapor retarder (ASTM E 1745 - Class A or B) shall be installed per the recommendations of the manufacturer, including afl penetrations (i.e., pipe, ducting, rebar, etc.). The vapor retarder should be underlain with 2 inches of washed sand, and should be overiain by a 2-inch thick layer of washed sand (SE>30). Concrete should have a maximum water/cement ratio of 0.50. This does not supercede the CBC (CBSC, 2007) for corrosion or other corrosive requirements. Additional concrete mix design recommendations should be provided by the structural consultant and/or waterproofing specialist. Concrete finishing and workablity should be addressed by the structural consultant and a waterproofing specialist. Mr. Bruce R. Bartlett W.O. 5892-A-SC Green Dragon Colonial Village, Carlsbad June 30, 2009 File;e:\wp9\5800\5892a.pgi Page 18 GeoSmls, Ine, Where slab water/cement ratios are as indicated above, and/or admixtures used, the structural consultant should also make changes to the concrete in the grade beams and footings in kind, so that the concrete used in the foundation and slabs are designed and/or treated for more uniform moisture protection. Owner(s) should be specifically advised which areas are suitable for tile flooring, wood flooring, or other types of water/vapor-sensitive flooring and which are not surtable. 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 specifled floor coverings indicated by the archrtect. Regardless of the mitigation, some limited moisture/moisture vapor transmission through the slab should be anticipated. Construction crews may require special training for installation of certain product(s), as well as concrete finishing techniques. The use of specialized product(s) should be approved by the slab designer and water-proofing consultant. A technical representative of the flooring contractor should review the slab and moisture retarder plans and provide comment prior to the construction of the foundations or improvements. The vapor retarder contractor should have representatives onsite during the initial installation. WALKWAYS. FLATWORK. AND OTHER IMPROVEMENTS The soil materials on site generally have a low expansion potential. 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 resurting potential for distress to improvements may be reduced, but not totally eliminated. To that end, rt is recommended that the developer should notify any interested/affected parties, ofthis 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 concrete slabs should be compacted to achieve a minimum 90 percent relative compaction, and then be presoaked to at least optimum moisture content, to a depth of 12 inches below subgrade elevation. The moisture content of the subgrade should be proof tested within 72 hours prior to pouring concrete. 2. Concrete slabs should be cast over a non-yielding surface, consisting of a 4-inch layer of crushed rock, gravel, or clean sand, that should be compacted and level prior to pouring concrete, tt low expansive soils are present, the rock or gravel or sand may be deleted. The layer or subgrade should be wet-down completely prior Mr. Bruce R. Bartlett —— W.0.5892-A-SC Green Dragon Colonial Village, Carlsbad June 30, 2009 File.e:\wp9\5800V5892a.pgi Page 19 GmSmls^ Me, to pouring concrete, to minimize loss of concrete moisture to the surrounding earth materiais. 3. Exterior slabs should be a minimum of 4 inches thick. Driveway slabs and approaches should addrtionally have a thickened edge (12 inches) adjacent to all landscape areas, to help impede infiltration of landscape water under the slab. 4. The use of transverse and longrtudinal control joints are recommended to help control slab cracking due to concrete shrinkage or expansion. Two ways to mrtigate such cracking are: a) add a sufficient amount of reinforcing steel, increasing tensile strength of the slab; and, b) provide an adequate amount of control and/or expansion joints to accommodate anticipated concrete shrinkage and expansion. In order to reduce the potential for unsightly cracks, slabs should be reinforced at mid-height with a minimum of No. 3 bars placed at 18 inches on center, in each direction, tt subgrade soils within the top 7 feet from finish grade are very low expansive soils (i.e., E.I. <20 and PI < 15). then 6x6-W1.4xW1.4 welded-wire mesh may be substituted forthe rebar, provided the reinforcement is placed on chairs, at vertical slab mid-height The exterior slabs should be scored or saw cut. to Vz inches deep (T/4. where T is the slab thickness, in inches), often enough so that no section is greater than 10 feet by 10 feet. For sidewalks or narrow slabs, control joints should be provided at intervals of every 6 feet The slabs should be separated from the foundations and sidewalks with expansion joint filler material. 5. No traffic should be allowed upon the newly poured concrete slabs until they have been properly cured to within 75 percent of design strength. Concrete compression strength should be a minimum of 2,500 psi. 6. Driveways, sidewalks, and patio slabs adjacent to the house should be separated from the house with thick expansion joint filler material. In areas directly adjacent to a continuous source of moisture (i.e., irrigation, planters, etc.), all joints should be addrtionally sealed with flexible mastic. 7. Planters and walls should not be tied to the commercial building(s). 8. Overhang structures should be supported on the slabs, or structurally designed with continuous footings tied in at least two directions. If very low expansion soils are present, footings need only be tied in one direction. 9. Any masonry landscape walls that are to be constructed throughout the property should be grouted and articulated in segments no more than 20 feet long. These segments should be keyed or doweled together. Mr. Bruce R. Bartlett W.O. 5892-A-SC Green Dragon Colonial Village, Carisbad june 30, 2009 File:e:\wp9\5800\5892a.pgi Page 20 GeoSotU, Ine, 10. Utilities should be enclosed within a closed utilidor (vault) or designed with flexible connections to accommodate differential settlement and expansive soil condrtions. 11. Positive site drainage should be maintained at all times. Finish grade on the lots should provide a minimum of 1 to 2 percent fall to the street, as indicated herein. It should be kept in mind that drainage reversals could occur, including post-construction settlement, rt relatively flat yard drainage gradients are not periodically maintained by the owner, and/or any interested/affected parties. 12. Shrinkage cracks could become excessive rt proper finishing and curing practices are not followed. Finishing and curing practices should be performed per the Portland Cement Association Guidelines. Mix design should incorporate rate of curing for climate and time of year, sulfate content of soils, corrosion potential of soils, and fertilizers used on srte. PRELIMINARY PAVEMENT DESIGN Based on the resistance value (R-value) evaluated for onsite soils, the following preliminary pavement sections are provided, in accordance wrth the respective value of the traffic index (T.I). The relatively low R-value test results are likely due to the non-plastic sitt content ofthe site soils. This material cannot be allowed to be saturated during placement and should have detailed positive drainage to extend pavement life. PRELIMINARY ASPHALTIC CONCRETE PAVEMENTS (ACP) TRAFFIC AREA TRAFFIC INDEX<^» SUBGRADE R-VALUE A.C. THICKNESS (INCHES) AGGREGATE BASE THICKNESS<^> (INCHES) Parking Areas 4.5 7 3.0 4.0 8.0 5.5 Driveway/ Truck Traffic areas 5.0 7 3.0 4.0 9.5 7.0 The type of street appropriate for the traffic index to be evaluated by the traffic engineer. Denotes Class 2 Aggregate Base ® >78, SE >25), or equivalent at 95 percent relative compaction PRELIMINARY PORTLAND CONCRETE CEMENT PAVEMENTS (PCCP) TRAFFIC AREAS CONCRETE Typl^ PCCP THICKNESS Parking Areas 560-C-3250 5.0 inches Driveway Areas 560-C-3250 6.0 Inches Truck Traffic Areas 560-C-3250 6.5 Inches NOTE: All PCCP is designed as un-reinforced and bearing directly on compacted subgrade. All PCCP should be properly detailed ftointinq, etc.) per the industrv standard. Mr. Bruce R. Bartlett Green Dragon Colonial Village, Carlsbad Fi[e:e:\wp9\5800\5892a.pgl W.O. 5892-A-SC June 30, 2009 Page 21 Ge^Smis, Ime, All subgrade (upper 6 inches) should be compacted to at least 95 percent relative compaction (per ASTM D 1557) prior to base paving. Aggregate base should be compacted to at least 95 percent relative compaction (per ASTM D 1557). All pavement construction should minimally be performed in general accordance with industry standards and properly transitioned. Final pavement design should be based on the actual design traffic Index for a given street area, and R-value testing performed at the conclusion of grading. Pavement design is based on the use of aggregate base conforming to specifications presented in Section 26 ofthe "Caltrans Standard Speciflcations" (Caltrans, 1995). Any existing concrete and asphalt may be used as aggregate road base onsite provided that the materials produced conform to specifications for either "crushed miscellaneous base" or "processed miscellaneous base" per Section 200 of the "Greenbook" Standard Specifications for Public Works Construction" (Public Works Construction, Inc.. 2003). WALL DESIGN PARAMETERS CONSIDERING SITE SOILS Conventional Retaining Walls The design parameters provided below assume that erther very low expansive soils (typically Class 2 permeable filter material or Class 3 aggregate base) or pre-approved and proof-tested native onsite materials are used to backfill any retaining walls. The type of backfill (i.e., select or native), should be specified bythe wall designer, and cleariy shown on the plans. Building walls, below grade, should be water-proofed. The foundation system for the proposed retaining walls should be designed in accordance with the recommendations presented in this and preceding sections ofthis report, as appropriate. Footings should be embedded a minimum of 18 inches below adjacent grade (excluding landscape layer, 6 inches) and should be 24 inches in width. There should be no increase in bearing for footing width. Recommendations for specialty walls (i.e., crib, earthstone, geogrid, etc.) can be provided upon request, and would be based on site specific conditions. 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 65 pcf, plus 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 City Mr. Bruce R. Bartlett W.O. 5892-A-SC Green Dragon Colonial Village, Carlsbad June 30, 2009 File;e:\wp9\5800\5892a.pgi Page 22 GeoSoU§f Ine, and/or County standard design. Active earth pressure may be used for retaining wall design, provided the top of the wall is not restrained fi-om minor deflections. An equivalent fluid pressure approach may be used to compute the horizontal pressure against the wall. Appropriate fluid unrt weights are given below for specific slope gradients ofthe retained material. These do not include otiier superimposed loading condrtions due to traflic, structures, seismic events or adverse geologic condrtions. When wall configurations are finalized, the appropriate loading conditions for superimposed loads can be provided upon request. If walls are supporting foundations or are placed such that they can affect exit or entry ft-om the building(s) or site, and are 6 feet or more in height, they should be designed to include a seismic surcharge of 10H uniform pressure (psf), where "H" is the gross height of the wall, and the resultant is at 0.6H up from the bottom of the footing. SURFACE SLOPE OF RETAINED MATERIAL (HORIZONTALzVERTICAL) EQUIVALENT FLUID WEIGHT P.C.F. (SELECT BACKFILL)** EQUIVALENT FLUID WEIGHT P.C.F. (NATIVE BACKFILL)*** Level* 2 to 1 40 55 50 70 * 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. ** Tested to have SE >i30, PI <15, E.I. <21 and <10% passing No. 200 sieve *** Tested to have E.I. <51. PI <15, E.I. <21 and <15% passing No. 200 sieve Retaining Wall Backfill and Drainage Positive drainage must be provided behind all retaining walls in the form of gravel wrapped in geofabric and outiets. 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 y4-inch to IVa-inch gravel wrapped in approved filter fabric (Mirafi 140 or equivalent). For low expansive backfill, the fitter material should extend a minimum of 1 horizontal foot behind the base of the vvalls and upward at least 1 foot. For native backfill that has an E.I. <50, continuous Class 2 permeable drain materials should be used behind the wall. This material should be continuous (i.e., full height) behind the wall, and rt 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 E.I. potential of greater than 50 or PI > 15 should not be used as backfill for retaining walls. 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). Mr. Bruce R. Bartlett Q 5892-A-SC Green Dragon Colonial Village, Carlsbad jupg 39 2009 File e:\wp9\5800\5892a.pgl Page 23 Ge^SoiUf Ine, (1) Waterproofing membrane CMU or reinf or ced-concrete wall Structural footing or settlement-sensrtive improvement Provide surface drainage via an engineered V-ditch (see civil plans for details) r- Proposed grade \ sloped to drain \ per precise civil \ drawings \ (5) Weep hole ^\-JL7>^ Footing and wall design by others 1:1 (h:v) or flatter backcut to be properly benched (6) Footing (1) Waterproofing membrane. (2) Gravel: Clean, crushed, % to 1)^ inch. (3) Filter fabric: Mirafi MON or approved equivalent (4) Viper- 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 hole: Minimum 2-inch diameter placed 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, use level fill or cut natural earth materials. An additional "heel" drain will likely be required by geotechnical consultant. RETAINING WALL DETAIL - ALTERNATIVE A Detail 1 (1) Waterproofing membrane CMU or reinforced-concrete wall Structural footing or settlement-sensitive improvement Provide surface drainage 2:1 (h:v) slope Footing and wall design by others (5) Weep hole —Proposed grade sloped to drain per precise civil drawings A\<^<<A\>\\\<<V;^ — (8) Native backfill (6) Clean sand backfill -1:1 (h:v) or flatter backcut to be properly benched (3) Filter fabric (2) Gravel (4) Pipe - (7) Footing (1) Waterproofing membrane Liquid boot or approved masticequlvalent. (2) Gravel: Clean, crushed, % to iK; inch. (3) Filter fabric: Mirafi MON or approved equivalent. (4) Pipe: 4-inch-diameter perforated PVC, Scheduie 40, or approved alternative with minimum of 1 percent gradient to proper outlet point (perforations down). (5) Weep hole: Minimum 2-inch diameter placed 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, use 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. RETAINING WALL DETAIL - ALTERNATIVE C Detail 3 Oi^tlets should consist of a 4-mch diameter solid PVC or ABS pipe spaced no greater than ± 100 feet apart, witii a minimum of two outlets, one on each end. The use of weep holes only, m vvalls higher than 2 feet, is not recommended. The surface of the backfill should be sealed by pavement or tiie top 18 inches compacted wrth 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 stmctures 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 civil designer may specify either: a) A minimum of a 2-foot overexcavation and recompaction of cut materials for a distance of 2H, ft-om the point of transition. b) Increase ofthe 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 ofthe transition may be accommodated. Expansion joints should be placed no greater than 20 feet on-center, in accordance wtth the structural engineer's/wall designer's recommendations, regardless of whether or not transition conditions exist Expansion joints should be sealed with a flexible, non-shrink grout c) Embed the footings entirely into native formational material (i e deepened footings). ' If transrtions from cut to fill transect the wall footing alignment at an angle of less than 45 degrees (pian view), then the designer should follow recommendation "a" (above) and until such transttion is between 45 and 90 degrees to the wall alignment. UTILITIES Utilities should be enclosed wrthin a closed utilidor (vault) or designed with flexible connections to accommodate differential settlement and expansive soil conditions Due to the potential for differential settiement, air conditioning (A/C) units rt not placed upon the commercial building roof, should be supported by slabs that are incorporated into the building foundation or constructed on a rigid slab wrth flexible couplings for plumbing and electrical lines. A/C waste waterlines should be drained to a suitable non- Mr. Bruce R. Bartlett " ~ , Green Dragon Colonial Village, Carlsbad , ' ^^^^'^ fS^ File:e:\wp9\.'5800\589?a pqi '^'^"^ ^009 Page 27 Ge@SmiSf Ine, DEVELOPMENT CRITERIA 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 ofslopes. Lot surface drainage should be carefljily taken into consideration during fine grading, landscaping, and building constmction. Therefore, care should betaken that future landscaping or construction activities do not create adverse drainage condrtions. Positive site drainage within lots and common areas should be provided and maintained at all times. Drainage should not flow uncontrolled down any descending slope. Water should be directed away from foundations and not allowed to pond and/or seep into the ground. In general, the area within 5 feet around a structure should slope away fl-om the structure. We recommend that unpaved lawn and landscape areas have a minimum gradient of 1 percent sloping away ft-om structures, and whenever possible, should be above adjacent paved areas. Consideration should be given to avoiding construction of planters adjacent to structures (buildings, pools, spas, etc.). Pad drainage should be directed toward the street or other approved area(s). Although not a geotechnical requirement roof gutters, down spouts, or other appropriate means may be utilized to control roof drainage. Down spouts, or drainage devices should outlet a minimum of 5 feet from structures or into a subsurface drainage system. Areas of seepage may develop due to irrigation or heavy rainfall, and should be anticipated. Minimizing irrigation will lessen this potential. If areas of seepage develop, recommendations for minimizing this effect could be provided upon request. Erosion Control Exposed graded surfaces will be subject to suriicial erosion during and after grading. Onsite earth materials have a moderate to high erosion potential. Consideration should be given to providing hay bales and sitt 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 utilized. An outlet placed in the bottom of the planter, could be installed to direct drainage away from structures or any exterior concrete flatwork. If planters are constructed adjacent to structures, the sides and bottom of the planter should be provided wrth a moisture barrierto 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. Mr. Bruce R. Bartlett W.O. 5892-A-SC Green Dragon Colonial Village, Carlsbad June 30, 2009 File:e:\wp9VS800\5892a.pgi Page 28 GeoS&ilB^ Ine, Owing to ttie relatively low R-value soils contemplated under the pavement areas the U<,P to tTu'^^^f '""^ "^'t^d, and consiSXn shoufd b^^^^ to the use of concrete cut-offs between planters and pavement areas. ^ ?hnMM Kareas should be planted wrth drought resistant vegetation Consideration should be given to ttie type of vegetation chosen and their potential effL upor^TurfS mprovements (,.e some trees will have an effect on co^ root systems). From a geotechnical standpoint leaching is not reS)rnmended^ estabhshmg landscaping. If the surface soils are processed forthe mrposrof addino amendments, they should be recompacted to 90 percent minimum reSe com Gutters and Downspouts 1°"^'^ discussed in the drainage section, the installation of gutters and downspouts should be considered to collect roof water that may othen«.ise infiltrL the soTad^ to the structures, ff utilized, the downspouts should be drained into PVC co"^cto^^^^^^^^^ or other non-erosive devices (e.g., paved swales or ditches; below grade sonSt-K PVC pipes; etc.). that will carry the water away from the stmcture. to arapproS^^ a^T.'^r^T^ the recommendations ofthe design civil engineer.Xwn^^^^^^^^ nnSiv T however, from a geotechnical viewpointTovided Thai posrtive drainage ,s incorporated into project design (as discussed preJ^ously) Subsurface and Surfar^P Vtfatgj- Subsurface and surface water are not anticipated to affect site development provided that the recommendations contained in this report are incorporated into final and constmction and that pmdent surface and subsurface drainage pracfcL are ncorpo^^^^^ into the constmction plans. Perched groundwater condrtions i^^ng Sn^of cX^ n^ permeabilities may not be precluded from occurring in the ftjture due to c.^f!firrio.^^^^^^ drainage condrtions. or damaged utilities, and shc^^ldteZlta^^^^^^ groundwater conditions develop, this office could as^ss thraSSfarea(srand?^^^^^^ the appropriate recommendations to mitigate the observergroundw^^^^^^^ Groundwater condrtions may change with the introduction of Irrigation, ^"faTor ler Site lm; If in the future, any addrtional improvements are planned for the site recommendation., conceming the geological or geotechnical aspects of design anTcons^uo^T^^^ improvements could be provided upon reauest Pnnk anHw u cons.™ced wllhcu, plan rLew by GS^"S shc°u,d be"no fin fill placenient, grading of the site, or trench backfilling after rough qradina hi bp^n Mr. Bruce R. Bartlett Green Dragon Colonial Village, Carlsbad Fife:e:\wp9\5800\5892a.pgi OcoSaiis, Ine, W.O. 5892-A-SC June 30, 2009 Page 29 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. Footinq Trench Excavation All footing excavations should be obsen/ed by a representative ofthis firm subsequent to trenching and prior to concrete form and reinforcement placement. The purpose of the observations is to evaluate that the excavations have been made into the recommended bearing material and to the minimum widths and depths recommended for construction, if loose or compressible materials are exposed within the footing excavation, a deeper footing or removal and recompaction ofthe subgrade materials would be recommended at that time. Footing trench spoil and any excess soils generated from utility trench excavations should be compacted to a minimum relative compaction of 90 percent, if not removed from the site. Trenchinq/Temporarv Construction Backcuts Considering the nature ofthe onsite earth materials, rt should be anticipated that caving or sloughing could be a factor in subsurface excavations and trenching. Shoring or excavating the trench walls/backcuts at the angle of repose (typically 25 to 45 degrees [except as specifically superceded wrthin the text ofthis report]), should be anticipated. All excavations should be observed by an engineering geologist or soil engineer from GSI, prior to workers entering the excavation or trench, and minimally conform to CAL-OSHA! state, and local safety codes. Should adverse conditions exist, appropriate recommendations would be offered at that time. Utilitv 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 Mr. Bruce R. Bartlett ~~ " " ' w.0.5892-A-SC Green Dragon Colonial Village, Carlsbad jj^ gg 2009 File.eAwpgvisooxssgaa.pgi Page 30 &€#Soils, Ine, (12-inch to 18-inch) under-slab trenches, sand having a sand equivalent value of 30 or greater may be utilized and jetted or flooded into place. Obsen/ation, probing and testing should be provided to evaluate the desired results. 2. Exterior trenches adjacent to, and within areas extending below alt plane projected from the outside bottom edge ofthe 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 ft-om 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 ofthe structural engineer. SUMMARY OF RECOMMENDATIONS REGARDIMH GEOTECHNICAL OBSERVATION AND TESTING We recommend that observation and/or testing be performed by GSI at each of the following construction stages: During grading/recertification. During excavation, Including building structures and pools/spas. During placement of subdrains, toe drains, or other subdrainage devices prior to placing fill and/or backfill. After excavation of building footings, retaining wall footings, free standing walls footings, and pools/spas, prior to the placement of reinforcing steel or concrete. 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 retarders (i.e., visqueen, etc.). During retaining wall subdrain installation, prior to backfill placement. During placement of backfill for area drain, interior plumbing, utility line trenches and retaining wall backfill. Mr. Bruce R. Bartlett ' W O 5892-A-SC Green Dragon Colonial Viiiage, Carlsbad ',, ,77^^ 7^^^ Fl!e:e.\wp9\5800\5892a.pgi ^"""^ GeoSmls, Ine, During slope construction/repair. When any unusual soil conditions are encountered during any construction operations, subsequent to the issuance of this report. When any improvements, such as flatwork, spas, pools, walls, etc., are constmcted, prior to construction. GSI should review and approve the plans for the proposed improvements, 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 srte work, and/or to comply with code requirements. 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 explicrt 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 or presented previously are not intended to preclude the transmission of water or vapor through the slab or foundation. The structural engineer/foundation and/or slab designer should provide recommendations to not allow water or vapor to enter into the structure so as to cause damage to another building component, or so as to limrt the installation of the type of flooring materials typically used for the particular application. 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 condrtions dictate, rt 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, rt analyses by the structural engineer/designer resutt 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 transmrt their requests to GSI. In order to mitigate potential distress, the foundation and/or improvement's designer should conflrm to GSI and the governing agency, in wrrting, that the proposed foundations and/or improvements can tolerate the amount of differential settlement and/or expansion characteristics and other design criteria specified herein. Mr. Bruce R. Bartlett W.O. 5B92-A-SC Green Dragon Colonial Village, Carlsbad June 30, 2009 File:e:\v/p9\5800\5892a.pgi Page 32 Ge®S®tl§, Ifff£» PLAN REVIEW Any additional project plans (grading, precise grading, foundation, retaining wall landscaping, pool/spa, etc.), should be reviewed by this office priorto constmction so that construction is in accordance with the conclusions and recommendations of this report Based on our review, supplemental recommendations and/or further geotechnical studies may be warranted. LIMITATIONS The materials encountered on the project site and utilized for our analysis are believed representative of the area; however, soil and bedrock materials vary in character between excavations and natural outcrops or condrtions exposed during mass gradinq Site conditions may vary due to seasonal changes or other factors. Inasmuch as our study is based upon our review and engineering analyses and laboratory data, the conclusions and recommendations are professional opinions. These opinions have been denved 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 rt our recommendations have been properly implemented. Use of this report constitutes an agreement and consent bythe user to all the limitations outlined above, notwithstandinq 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 sen/ices or this portion ofthe project. All samples will be disposed of after 30 days unless specifically requested by the client, in writing. ' Mr. Bruce R. Bartlett ' r— Green Dragon Colonial Village, Carlsbad , ' ^^^^-A-SC File:e:\wp9\.'5800V'-,892a pgi "® ^^^^ Page 33 Ge&Soils, Ine, APPENDIX A REFERENCES APPENDIX A REFERENCES American Concrete Institute, 2004, Guide for concrete floor and slab construction: reported by ACI Committee 302; Designation ACI 302.1 R-04, dated March 23. American Society for Testing and Materials, 1998. Standard practice for installation of water vapor retarder used in contact with earth or granular fill under concrete slabs. Designation: E 1643-98 (Reapproved 2005). . 1997, Standard speciflcafion for plastic water vapor retarders used in contact wrth soil or granular fill under concrete slabs. Designation: E 1745-97 (Reapproved 2004). Blake, T.F., 2000a, EQFAULT, A computer program forthe estimation of peak horizontal acceleration from 3-D fault sources; Windows 95/98 version, updated to September, 2004. . 2000b, EQSEARCH, A computer program for the estimation of peak horizontal acceleration fi'om Califomia historical earthquake catalogs; Updated through June 2008, Windows 95/98 version. . 2000c, FRISKSP, A computer program for the probabilistic estimation of peak acceleration and uniform hazard spectra using 3-D faults as earthquake sources; Windows 95/98 version, updated to September, 2004. Bozorgnia, Y., Campbell, K.W., and Niazi, M., 1999, Vertical ground motion: Characteristics, relationship with horizontal component and building-code implications; Proceedings of the SMIP99 seminar on utilization of strong-motion data, Oakland, pp. 23-49, September, 15. Bryant, W.A., and Hart, E.W., 2007, Fautt-rupture hazard zones in California: California Geological Sun/ey, Special Publication 42, Interim Revisions. California Building Standards Commission, 2007, California Building Code. California, State of, 2009, Civil Code, Trtle 7. Division 2, Section 895, et seq. Campbell, K.W. and Bozorgnia, Y., 1997, Attenuation relations for soft rock conditions; jn EQFAULT, A computer program for the estimation of peak horizontal acceleration from 3-D fauft sources; Windows 95/98 version, Blake, 2000a. Eisenberg, L., 1983, Pleistocene marine terrace and eocene geology, Encinitas and Rancho Santa Fe Quadrangles, San Diego County, California, 1" =2200' scale, Plate 3, jn Abbott, P.L. Ed., On the manner of deposition ofthe Eocene strata in Northern San Diego County, dated April 13. 1985. GeoS&USf Ine, GeoSoils, Inc., 2009, Proposal for a Preliminary Geotechnical Investigation, Proposed Green Dragon Colonial Village (Formeriy Hadley's), Paseo Del Norte, City of Carisbad, San Dlego County, California, P.N. 0903-22, dated April 27. Jennings, C.W., 1994, Fautt activity map of Calrtornia and adjacent areas: California Division of Mines and Geology, Map sheet no. 6. scale 1:750.000. Kanare, Howard, 2005, Concrete floors and moisture, Portland Cement Association. Skokie, Illinois. Kennedy, Michael P., and Tan, Saing S., 2005, Geologic map ofthe Oceanside 30' x 60' quadrangle, California, United States Geological Survey. O'Day Consultants, 2008, Site Development Plan, for Green Dragon Colonial Village, 4 Sheets, Job No. 08-1240, dated May. Public Work Construction, Inc., 2003, Greenbook, Standard specrtlcationsfor public works construction. Sadigh, K., Egan, J., and Youngs, R., 1987, Predictive ground motion equations, in Joyner, W.B. and Boore, D.M., 1988, measurement, characterization, and prediction of strong ground motion, jn Von Thun, J.L., ed.. Earthquake engineering and soil dynamics II, recent advances in ground motion evaluation, American Society of Civil Engineers Geotechnical Special Publication No. 20, pp. 43-102. State of California, Department ofTransportation, 1995, Caltrans standard speciflcations. Tan, S.S., and Giffen, D.G., 1995, Landslide hazards in the northern part ofthe San Diego Metropolitan area, San Diego County, California, Landslide hazard identification map no. 35, Plate E, Department of Conservation, Division of Mines and Geology, DMG Open File Report 95-04. Tan, S.S., and Kennedy, Michael P., 1996, Geologic maps ofthe northwestem part of San Diego County, California: California Division of Mines and Geology, Open File Report 96-02. Mr. Bruce R. Bartlett Appendix A File:e:\wp9\5300\5092a.pgi Page 2 ^"^ J ' f =i . ^ J si Jiij- APPENDIX B BORING LOGS UNIFIED SOIL CLASSIFICATION SYSTEM CONSISTENCY OR RELATIVE DENSITY Major Divisions Group Symbols Typical Names CRITERIA o a d o 2: CO c TJ O s s O 'S ID 1 on" i-2 .5 o S o m ^ 2 Z 2 k "B o f T o 10 o ffl ° C S — ^ CD «S St 0) to m n ffl GW Well-graded gravels and gravel- sand mixtures, little or no fines Standard Penetration Test O Q GP Poorly graded gravels and gravel-sand mixtures, little or no fines ? x: CJ ^ QM Silty gravels gravel-sand-silt mixtures GC Clayey gravels, gravel-sand-clay mixtures sw Well-graded sands and gravelly sands, little or no fines Penetration Resistance N (blows/ft) Relative Density 0-4 Very loose 4-10 Loose 10-30 Medium 30-50 Dense > 50 Very dense SP Poorly graded sands and gravelly sands, little or no fines SM Siity sands, sand-silt mixtures Ui l'-se Clayey sands, sand-clay mixtures jn CM o d «> Z 12 M OJ 0) £ « to a >- Co C3 Q. E o u- £ o ML Inorganic silts, very fine sands, rock flour, silty or clayey line sands Standard Penetration Test O J 51 cr 0^ £ —I m CL Inorganic clays of low to medium plasticity, gravelly ciays, sandy clays, silly clays, lean clays OL Organic silts and organic silty clays of low plasticity "is MH Inorganic silts, micaceous or diatomaceous fine sands or silts, elastic silts CH Inorganic clays of high plasticity, fat clays OH Organic clays of medium to high plasticity Penetration Resistance N (blows/ft) Consistency Unconfined Compressive Strength (tons/ff) <2 Very Soft <0.25 2-4 Soft 0.25 - .050 4-8 Medium 0.50-1.00 8-15 Stiff 1.00-2.00 15-30 Very Stiff 2.00 - 4.00 >30 Hard >4.00 Highly Organic Soils PT Peat, mucic, and other highly organic soils 3" 3/4" #4 #10 #40 #200 U.S. Standard Sieve Unifled Soil Classification Cobbles Gravel Sand Silt or Clay Unifled Soil Classification Cobbles coarse flne coarse medium fine Silt or Clay MOISTURE CONDITIONS Dry Absence of moisture: dusty, dry to the touch Slightly Moist Below optimum moisture content for compaction Moist Near optimum moisture content Very Moist Above optimum moisture content Wet Visible free water, below water table MATERIAL QUANTITY trace 0 - 5 % few 5 - 10 % little 10-25% some 25 - 45 % OTHER SYMBOLS C S B Core Sample SPT Sample Bulk Sample Groundwater Qp Pocket Penetrometer BASIC LOG FORMAT: Group name. Group .symbol, (grain size), color, moisture, consistency or relative density. Additional comments: odor, presence of tools, mica, gypsum coarse grained particles, etc. EXAMPLE: Sand (SP), fine to medium grained, brown, moist, loose, trace silt, little fine gravel, few cobbles up to 4° in size, some hair roots and rootlets. File:Mgr: c;\SollClassif.wpd PLATE B-1 GeoSoils, Inc. PROJECT: GREEN DRAGON/BARTLETT 6115 Paseo Del Norte, Carlsbad BORING LOG iv.o. 5892-A-SC BORING Bll SHEETJ}_ OF 2 DATE EXCAVATED 5-13-09 LOGGED BY: RBB SAMPLE METHOD: Moditied Sampler, 140 Ibs @ 30" Drop Approx. Elevation: 74" MSL Standatd Penetration Test Undisturbed, Ring Sample SL Groundwater Description of Material TOPSOIUARTIFICIAL FILL: \ @ 0' SANDY SILT, dark grayish brown, dry, soft; porous. ©1/6" CLAYEY SAND, light brown, dry becoming moist with depth, y loose becoming medium dense with depth. QUATERNARY TERRACE DEPOSITS: @ 2W SANDY CLAY, gray, damp, hard. @ 5' SILTY SAND, light brown to light birownish gray, moist, very dense. @ 10' SILTY SAND, brown, moist, dense to SANDY clj\Y, dark brown, moist, hard. @ 12' SANDY CUVY, brown to dark brown, moist, hard' @ 15' SAND, light brown, damp, medium dense; fine grained, friable. @ 20' SILTY SAND, light reddish yellow, moist, dense. @ 25' SAND, light gray to light reddish yellow, damp, dense; fine grained, friable. 6115 Paseo Oel Norte. Carisbad GeoSoils, lme. Plate B-2 BORING LOG GeoSoils, Inc. PROJECT: GREEN DRAGON/BARTLETT 6115 Paseo Del Norte, Carlsbad W.O. 5892-A-SC BORING B-1 SHEET 2 QF 2 DATEEXCAVATED 5-13-09 LOGGED BY;RBB Sample 31^ 32- 33 34 35 36 37 38-1 39 40 4H 42 43 44 45 46 47 48 49 50 51 52 M 53 64 55 56 57 58 59 72 S3 E U) tn a w 3 SP Q SAMPLE METHOD: Modified Cal Sampler, 140 Ibs @ 30" Drop Standard Penetation Test Undisturbed, Ring Sample Approx. Elevation: 74' MSL 2 Groundwater Description of Material @ 30' SAND, light brown, wet, dense; fine grained, friable, no recovery due to lost sampler. @ 31' Groundwater encountered. \ @ 35' Likely as per 3D'. Total Depth = 35"" ' Groundwater Encountered @ 31' No Caving Encountered Backfilled 5-13-5009 6115 Paseo Del Norte. Carfsbad ©•©©Soils, Plate B-3 GeoSoils, Inc. BORING LOG W.O. 5892-A-SC PROJECT: GREEN DRAGON/BARTLETT 6115 Paseo Del Norte, Carlsbad BORING B-2 SHEET 1 OF 1 DATEEXCAVATED 5-13-09 LOGGED BY: RBB Sample 2 4 5-f 9- 10 11 12- 13 14- 15 16 17 18 19 20 21 22 23- 24- 25 26- 27 28- 29- r 11 25 13/ 50-6" SC/CL 32 41 CO CO o CO 3 CL CL CL 3 Q 109.3 119.5 110.8 15.4 11.4 9.2 6115 Paseo Dei Norte. Carfsbad 79.3 78.4 SAMPLE METHOD: Moditied Cal Sampler, 140 Ibs @ 30" Drop Standard Penetration Test Undisturbed, Ring Sample Approx. Elevation: 74' MSL 2 Groonc/ivafer Description of Material PAVEMENT SECTION: @ C Asphaltic concrete, 2-3 inches thick. ARTIFICIAL FILL - UNDOCUMENTED: @ l/g SANDY CLAY, brown to gray, wet, soft. QUATERNARY TERRACE DEPOSITS: @ 1' SANDY CLAY, brown to gray, wet, stiff. @ 3' SANDY CLAY, brown to gray, damp, very stiff. 49.5 @ 5' CLAYEY SAND/SANDY CLAY, brown to gray, damp, dense/hard. ^^^^ m @ 10' SANDY CLAY, dark brown to brown, wet, very stiff. @ 15' SANDY CLAY, gray to reddish brown, damp, hard. Total Depth = Iff No Groundwater or Caving Encountered Backfilled 5-13-5009 GeoSoils, Inc. Plate B-4 BORING LOG GeoSoils, Imm, PROJECT: GREEN DRAGON/BARTLETT 6115 Paseo Del Norte, Carisbad W.O. 5892-A-SC BORING B-3 SHEET 1 OF 1 DATE EXCAVATED 5-13-09 LOGGED BY: RBB Sample 1 2 3 4 5 6 7 8 9 10 11 12 13 14- 15- 16- 17 18- 19- 20- 21- 22- 23- 24 25- 25 27- 28- 29- 61 CO to o CO 3 SC/CL 56 34 33 SC/CL 46 33 SM SM/CL a 105.2 110.8 86.9 116.0 CL 6.1 12.3 11.3 12.1 SAMPLE METHOD: SAodified Cal Sampler, 140 Ibs @ 30" Drap Standard Penetation Test Undisturbed, Ring Sample Approx. Elevation: 76' MSL S Groundwater Description of Material 28.0 66.2 33.0 PAVEMENT SECTION: @ 0' Asphaltic concrete. 2-3 inches thick. ARTIFICIAL FILL - UNDOCUMENTED: @ 1/6' CLAYEY SAND/SANDY CLAY, light brown to yellowish brown, dry becoming moist with depth, medium dense. QUATERNARY TERRACE DEPOSITS: \ @ 1' SILTY SAND, light brown, damp, dense; slightly plastic. @ 3' SILTY SAND, light brown, damp, medium dense to SANDY CLAY, brown to dark gray, moist, very stiff. @ 5' CLAYEY SAND/SANDY CLAY, light brown to reddish yellow, moist, dense/hard. 75.3 @ 10' SILTY SAND, light brown, damp, dense to SANDY CLAY, brown to dark gray to reddish brown, moist hard. @ 15' SANDY CLAY, gray, moisL very stiff. Total Depth = 16' No Groundwater or Caving Encountered Backfilled 5-13-5009 I ..i 15 Paseo Del NorlB, Carlsbad Plate B-5 APPENDIX C EQFAULT, EQSEARCH, AND FRISKSP * EQFAULT * * * version 3.00 * ******* *4***ft***4.****4* DETERMINISTIC ESTIMATION OF PEAK ACCELERATION FROM DIGITIZED FAULTS JOB NUMBER: 5892-A-SC DATE: 05-14-2009 JOB NAME: GREEN DRAGON/BARTLETT CALCULATION NAME: 5892 FAULT-DATA-FILE NAME: C:\Program Files\EQFAULTl\CGSFLTE.DAT SITE COORDINATES: SITE LATITUDE: 33.1204 SITE LONGITUDE: 117.3198 SEARCH RADIUS: 62.14 mi ATTENUATION RELATION: 11) Bozorgnia Campbell Niazi (1999) Hor.-Pleist. soil-Cor. UNCERTAINTY CM=Median, S=Sigma): s Number of sigmas: 1.0 DISTANCE MEASURE: cdiSt SCOND: 1 Basement Depth: .00 km Campbell SSR: 0 Campbell SHR: 0 COMPUTE PEAK HORIZONTAL ACCELERATION FAULT-DATA FILE USED: C:\Program Files\EQFAULTl\CGSFLTE.DAT MINIMUM DEPTH VALUE (.km): 3.0 Page 1 W.O. 5892-A-SC PLATE C-1 Ge®Seil§, Ime, EQFAULT SUMMARY DETEIWINISTIC SITE PARAMETERS Page 1 ABBREVIATED FAULT NAME ROSE CANYON NEWPORT-INGLEWOOD (Offshore) CORONADO BANK ELSINORE (JULIAN) ELSINORE (TEMECULA) ELSINORE (GLEN IVY) PALOS VERDES SAN JOAQUIN HILLS EARTHQUAKE VALLEY SAN JACINTO-ANZA NEWPORT-INGLEWOOD (L.A.Basin) SAN JACINTO-SAN JACINTO VALLEY CHINO-CENTRAL AVE. (Elsinore) SAN JACINTO-COYOTE CREEK WHITTIER ELSINORE (COYOTE MOUNTAIN) SAN JACINTO-SAN BERNARDINO t*****i t********************** 4.5( 7.0( 20.2( 25.2( 25.2( 36.2( 37.7( 37.9( 43.0( 47.9( 48.5( 48.8( 50.4( 52.4( 54.3( 56.5( 62.1( 7.2) 11.3) 32.5) 40.5) 40.5) 58.2) 60.6) 61.0) 69.2) 77.1) 78.1) 78.5) 81.1) 84.4) 87.4) 90.9) 100.0) ESTIMATED MAX. EARTHQUAKE EVENT MAXIMUM EARTHQUAKE MAG. (Mw) 7.2 7.1 PEAK SITE ACCEL. 6.7 6.6 6.8 6.8 6.7 0.663 0.506 0.284 0.164 0.134 0.092 0.125 0.109 0.063 0.091 0.083 0.072 0.086 0.054 0.060 0.058 0.049 EST. SITE INTENSITY MOD.MERC. -END OF SEARCH- 17 FAULTS FOUND WITHIN THE SPECIFIED SEARCH RADIUS. THE ROSE CANYON FAULT IS CLOSEST TO THE SITE IT IS ABOUT 4.5 MILES (7.2 km) AWAY. LARGEST MAXIMUM-EARTHQUAKE SITE ACCELERATION: 0.6628 g XI X IX VIII VIII VII VII VII VI VII VII VI VII VI VI VI VI Page 2 W.O. 5892-A-SC PLATE C-2 GeoS&Us, Ine, MAXIMUM EARTHQUAKES GREEN DFIAGON/BARTLETT 3 c o *3 CS s_ o o o < .1 .01 .001 1 1 m Bf H i 4 k i •< i • • -1 1 1 • 1 1 1 1 1 S2i M .1 10 Distance (mi) 100 W.O. 5892-A-SC PLATE C-3 GemS®tl$f ime. ***************JtJL.JUJL.JJ.JUJS.J^jLJL * * * EQSEARCH * * * * version 3.00 * * * ***************J^Jt^Jt.J-JLJLJtJl.JL ESTIMATION OF PEAK ACCELERATION FROM CALIFORNIA EARTHQUAKE CATALOGS JOB NUMBER: 5892-A-SC DATE: 05-14-2009 JOB NAME: GREEN DRAGON/BARTLET EARTHQUAKE-CATALOG-FILE NAME: ALLQUAKE.DAT SITE COORDINATES: SITE LATITUDE: 33.1204 SITE LONGITUDE: 117.3198 SEARCH DATES: START DATE: 1800 END DATE: 2008 SEARCH RADIUS: 62.1 mi 100.0 km ^'^nl^r^IiATM^^'-rM^^^A- Bozorgnia Campbell Niazi (1999) Hor.-Pleist. Soil-Cor. UNCERTAINTY (M=MedTan, s=Sigina): s Number of sigmas: 1.0 c™^^ Css=strike-slip, DS=Reverse-slip, BT=Blind-thrust] SCOND: 1 Depth source: A Basement Depth: .00 km Campbell ssR: 0 Campbell SHR- 0 COMPUTE PEAK HORIZONTAL ACCELERATION nr^. u MINIMUM DEPTH VALUE (km): 3.0 Page 1 W.O. 5892-A-SC PLATE C-4 GeoSoils, Ine, EARTHQUAKE SEARCH RESULTS Page 1 FILE LAT. LONG. CODE NORTH WEST DMG 33 .0000 117 .3000 MGI 33 .0000 117 .0000 MGI 32 .8000 117 .1000 DMG 32 .7000 117 .2000 T-A 32 .6700 117 .1700 T-A 32 .6700 117 .1700 T-A 32 .6700 117 .1700 PAS 32 .9710 117 .8700 DMG 33 .2000 116 .7000 DMG 32 .8000 116 .8000 DMG 33 .7000 117 .4000 DMG 33 .7000 117 .4000 DMG 33 .7000 117 .4000 DMG 33 .6990 117 .5110 MGI 33 .2000 116 .6000 DMG 33 .7100 116 .9250 DMG 33 .7500 117 .0000 DMG 33 .7500 117 .0000 DMG 33 .5750 117 .9830 MGI 33 .8000 117 .6000 DMG 33 .8000 117 .0000 DMG 33 6170 117 9670 GSP 33 5290 116 5720 DMG 33 OOOO 116 4330 DMG 33 6170 118 0170 PAS 33 5010 116 5130 GSP 33 5080 116 5140 DMG 33 5000 116 5000 DMG 33 9000 117 2000 DMG 33. 6830 118 0500 DMG 33. 3430 116. 3460 DMG 33. 7000 118. 0670 DMG 33. 7000 118. 0670 DMG 34. OOOO 117. 2500 T-A 32. 2500 117. 5000 MGI 34. OOOO 117. 5000 DMG 33. 7500 118. 0830 DMG 33. 7500 118. 0830 DMG 33. 7500 118. 0830 DMG 1 33. 7500 118. 0830 DMG 1 33. 7500 118. 0830 DMG 1 33. 4000 116. 3000 DATE TIME (UTC) H M sec + + 2130 0.0 730 0.0 0 0 0.0 20 0 0.0 0 0 0.0 0 0 0.0 0 0 0.0 1347 8.2 235 0.0 23 3 0.0 620 0.0 757 0.0 1547 0.0 83455.4 1748 0.0 144152.6 223225.0 2232 0.0 518 4.0 2115 0.0 1225 O.OI 154 7.8 154146.5 1035 8.3 19 150.0 104738.5 075616.6 211 0.0 0 0 0.0 658 3.0 232042.9 51022.0 85457.0 73026.0 20 0 0.0 10 0 0.0 230 0.0 131828.0 323 0.0 2 9 0.0 910 0.0 12 6 0.0 DEPTH (km) QUAKE MAG. SITE ACC. g ISITE I MM I INT, + + IX VI VI VI v V V V V VI V V VI V V IV VI IV V IV VI VI IV IV IV V IV IV V V V IV IV V IV VI IV IV IV IV IV V APPROX. DISTANCE mi [km] 11/22/1800 09/21/1856 05/25/1803 05/27/1862 10/21/1862 12/00/1856 05/24/1865 07/13/1986 01/01/1920 10/23/1894 05/13/1910 04/11/1910 05/15/1910 05/31/1938 10/12/1920 09/23/1963 04/21/1918 06/06/1918 03/11/1933 04/22/1918 12/25/1899 03/11/1933 06/12/2005 06/04/1940 03/14/1933 02/25/1980 10/31/2001 09/30/1916 12/19/1880 03/11/1933 04/28/1969 03/11/1933 03/11/1933 07/23/1923 01/13/1877 12/16/1858 03/11/1933 03/13/1933 03/11/1933 03/11/1933 I 03/11/19331 02/09/18901 0.0 0.0 0.0 0.0 0.0 0.0 0.0 6.0 0.0 0.0 0.0 0.0 0.0 10.0 0.0 16.5 0.0 0.0 0.0 0.0 0.0 0.0 14.0 0.0 0.0 13.6 15.0 0.0 0.0 0.0 20.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 6.50 5.00 5.00 5.90 5.00 5.00 5.00 5.30 5.00 5.70 5.00 5.00 6.00 5.50 5.30 5.00 6.80 00 20 00 40 30 20 5.10 5.10 5.50 5.10 5.00 6.00 5.50 5.80 5.10 5.10 6.25 5.00 7.00 5.10 5.30 5.00 5.00 5.10 6.30 0.318 0.054 0,043 0.063 0.034 0.034 0.034 0.038 0.030 0.044 0.027 0.027 0.049 0.035 0.030 0.023 0.070 0.023 0.024 0.021 0.050 0.046 0.023 0.022 0.021 0.027 0.021 0.020 0.035 0.025 0.029 0.019 0.019 0.037 0.017 0.060 0.018 0.020 0.017 0.017 0.018 0.037 8.4( 20.3( 25.5( 29.8( 32.3( 32.3( 32.3( 33.5( 36.2( 37.4( 40.3( 40.3( 40.3( 41.4( 42.0( 46.6( 47.2( 47.2( 49.5( 49.6( 50.4( 50.7( 51.5( 52.0( 52.8( 53.5( 53.6( 54.1( 54.3( 57.3( 58.3( 58.8( 58.8( 60.9( 61.0( 61.6( 61.8( 61.8( 61.8( 61.8( 61.8( 62.0( 13.5) 32.6) 41.1) 48.0) 52.0) 52.0) 52.0) 53.9) 58.3) 60.1) 64.8) 64.8) 64.8) 66.7) 67.5) 75.0) 76.0) 76.0) 79.6) 79.8) 81.1) 81.5) 82.9) 83.7) 85.0) 86.0) 86.3) 87.0) 87.3) 92.2) 93.8) 94.6) 94.6) 97.9) 98.2) 99.1) 99.5) 99.5) 99.5) 99.5) 99.5) 99.7) "it "iz it'is Page 2 W.O. 5892-A-SC PLATE C-5 Ge&Soits, Ine. -END OF SEARCH- 42 EARTHQUAKES FOUND WITHIN THE SPECIFIED SEARCH AREA. TIME PERIOD OF SEARCH: 1800 TO 2008 LENGTH OF SEARCH TIME: 209 years THE EARTHQUAKE CLOSEST TO THE SITE IS ABOUT 8.4 MILES (13.5 km) AWAY. LARGEST EARTHQUAKE MAGNITUDE FOUND IN THE SEARCH RADIUS: 7.0 LARGEST EARTHQUAKE SITE ACCELERATION FROM THIS SEARCH: 0.318 g *"°a-value-^%'^865^"^^^^^'*^ * RICHTER RECURRENCE RELATION: b-value= 0.357 beta-value= 0.822 TABLE OF MAGNITUDES AND EXCEEDANCES: Earthquake Magni tude Number of Times Exceeded Cumulative No. / Year 4.0 4.5 5.0 5.5 6.0 6.5 7.0 42 42 42 15 9 3 1 0.20192 0.20192 0.20192 0.07212 0.04327 0.01442 0.00481 Page 3 W.O. 5892-A-SC GeoSoils, lite. PLATE C-6 100 EARTHQUAKE RECURRENCE CURVE GREEN DRAGON/BARTLET (0 o CO +.» n > LU X2 E 2 Oi > JCB Ol E E Zl O .001 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 Magnitude (IVI) W.O. 5892-A-SC PLATE C-7 6e#S#lls, Ine, 1100 1000 - 900 800 700 600 -- 500 400 300 200 -- 100 0 — EARTHQUAKE EPICENTER MAP GREEN DRAGON/BARTLET •100 -400 -300 -200 -100 0 100 200 300 400 500 600 W.O. 5892-A-SC PLATE C-8 GeoSoils, Inc. 100 J3 CO J2 O I.. QL U c ta T3 0) 0) U X UJ PROBABILITY OF EXCEEDANCE BOZ. ET AL.(1999)HOR PS COR 2 0.00 0.25 0.50 0.75 1.00 Acceleration (g) 1.25 1.50 W.O. 5892-A-SC PLATE C-9 Ge#Soils, Ine, I Go o Mt .0 tn CO ro I > CO n RETURN PERIOD vs. ACCELERATION BOZ. ETAL(1999)HOR PS COR 2 1000000 S2 o o a. 3 >»-» QC •a m O 100000 10000 1000 100 0.00 0.25 0.50 0.75 1.00 Acceleration (g) 1.25 1.50 60 f 50 UJ 40 Q t: o 30 OT < 20 10 CL GH y y y y y y y y y y y y y y y y y y y y y y y y / y y y y y y • / ML MH CL-^L ML MH 1 \ ML MH 20 40 60 LIQUID LIMIT 80 100 Sample e B-2 Depth/El. 1.0 LL 36 PL 16 PI 20 Fines USCS CLASSIFICATION Clay GeoSoUs, Issc. GeoSoils, Inc. 5741 Palmer Way Cadsbad, CA 92008 Telephone: (760)438-3155 Fax; (760)931-0915 ATTERBERG LIMITS' RESULTS Project GREEN DRAGON/BARTLETT Number: 5892-A-SC Date: June 2009 Plate: D - 1 3,000 2,500 2,000 X H-o 2 Ui a: \-tn < Ui X w 1,500 1,000 500 500 1,000 1.500 2,000 2,500 3,000 NORMAL PRESSURE, psf Sample Depth/El. Range Classification Primary/Residual Sample Type Yd MC% C <!> cn • B-1 20.0 Silty Sand Primary Shear Undisturbed 111.6 6.5 409 29 i • B-1 20.0 Residual Shear Undisturbed 111.6 6.5 422 27 t-Q q < Note; Sample Innundated prior to testing oj o> fXI —•—-— - GeoSoils, Itut. GeoSoils, Inc. 5741 Palmer Way Carisbad, CA 92008 Telephone; (760)438-3155 Fax: (760)931-0915 DIRECT SHEAR TEST Project; GREEN DRAGON/BARTLETT Number 5892-A-SC Date: June 2009 Plate: D TEST SPECIMEN B Compactor air pressure PSI 100 75 50 Water added % 5.9 7.7 9.4 Moisture at compaction % 15.0 17.0 18.9 Height of sample IN 2.43 2.51 2.59 Dry density PCF 114.1 109.4 105.1 R-Value by exudation 11 8 7 R-Value by exudation, corrected 11 8 7 Exudation pressure PSI 725 402 249 Stability thickness FT 1.14 1.18 1.19 Expansion pressure thickness FT 1.47 1.00 0.57 DESIGN CALCULATION DATA Traffic index, assumed 5.0 Gravel equivalent factor, assumed 1.25 Expansion, stability equilibrium 1.17 R-Vaiue by expansion 9 R-Value by exudation 7 R-Value at equilibrium 7 Expansion, Stability Equilibrium 2 00 £•1.50 3 ns >0. o o .1.00 50 0.00 — 7 -• — -• — ... — ... - Al ... - Al ... ... -— - Al ... ... -— —i / —, ..... 7 — —, ..... 7 — —, ..... —, 7 — — 7 — — 7 i — 7 4- -• -- -— - -7 7 7 i 4- -• -- -— - -7 7 7 i -- -— - -7 7 7 7 SAMPLE INFORMATION Sample Location: B-2 @ 0-2 Sample Description: Dark Gray Brown Clay W/ Sand Notes: Test Method: 0) to > fk 80 70 60 50 40 30 20 10 0 0% Retained on 3/4 inch sieve Cal-Trans Test 301 R-Value By Exudation 0 00 0.50 1.00 1.50 2.00 Cover Thickness by Expansion Pressure (ft) 800 700 600 500 400 300 200 Exudation Pressure (psi) 100 GeoSoils, Inc. ~jC-j) 5741 Palmer Way ' Carlsbad, CA 92008 '-7 Telephone: (760) 438-3155 Fax: (760) 931-0915 R - VALUE TEST RESULTS Project; GREEN DRAGON/BARTLETT Number: 5892-A-SC Date: June 2009 Plate: D-3 Prime Testing, Inc. 41895 Elm Sfreet Ste 201 Murrieta, CA 92562 ph (951) 894-2682 • fic (951) 894-2583 Work Order No.: 9E5200 Client: GeoSoils, Inc. (Carlsbad) Project No.: 5298-A-SC Project Name: Green Dragon Report Date: June 3, 2009 Laboratorv Testfs) Results Summarv The subject soil sampie was processed in accordance with California Test Method CTM 643 and tested for pH / Minimum Resistivity (CTM 643), Sulfate Content (CTM 417) and Chloride Content (CTM 422). The test results follow: Sample Identification pH Minimum Resistivity (ohm-cm) Sulfate Content (mg/kg) Sulfate Content (% by wgt) Chloride Content (ppm) B-2 @ 1-3" 7.6 550 360 0.036 70 *ND=No Detection We appreciate the opportunity to serve you. Please do not hesitate to contact us with any questions or clarifications regarding these results or procedures. Ahmet K. Kaya, Laboratory Manager M EMBER W:0. 5892-A-SC www. primetesting. com Form IMo. CP-IR PLATE J^n05/06 APPENDIX E GENERAL EARTHWORK, GRADING GUIDELINES AND PRELIMINARY CRITERIA GENERAL EARTHWORK. GRADING GUIDELINES. AND PRELIMINARY CRITFRIA General These guidelines present general procedures and requirements for earthwork and gradinq 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 wou Id 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 ofthe project plans and specifications and latest adopted code In the case of conflict, the most onerous provisions shall prevail. The project geotechnical engineer and engineenng geologist (geotechnical consultant), and/or their representatives should provide observation and testing services, and geotechnical consultation durinq the duration of the project. EARTHWORK OBSERVATIONS AND TESTING Geotechnical Consultant Priorto the commencement of grading, a qualified geotechnical consultant (soil engineer and engineenng geologist) should be employed for the purpose of observing earthwork procedures and testing the fills for general conformance with the recommendations ofthe 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 rnay be made that the work is being accomplished as specified. It is the responsibilitv of the coritractor 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 bythe geotechnical consiiltant pnor to placing any fill. It is the contractor's responsibility to notify the geotechnical consultant when such areas are ready for observation. Laboratorv and Field Test.s Maximum dry density tests to determine the degree of compaction should be performed in accordance with American Standard Testing Materials test method ASTM designation D-1557. Random or representative field compaction tests should be performed In GeoSoils, Ine, accordance with test methods ASTM designation D-1556, D-2937 or D-2922, and D-3017, at intervals of approximately ±2 feet of flll 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 ofthe 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 ofthe contractorto provide adequate equipment and methods to accomplish the earthwork in strict accordance with applicable grading guidelines, latest adopted codes 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 forthe 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 properiy 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 shouid be approved by the geotechnical consultant. Mr. Bruce R. Bartlett Appendix E File:e:\wp9\5800\5892a.pgi Page 2 Ge&SoUs, ine^ 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, highly fractured, or othenwise 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 properiy 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 ofthe 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. Ifthe scarified zone is greaterthan 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 hanowing, 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 fi-ee 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 ofthe 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 speciflcally recommended othenwise bythe geotechnical consultant, the minimurn width of fill keys should be equal to Vz 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 properiy placed and compacted until design grades (elevations) are attained. Mr. Bruce R. Bartlett ' ~~ ~i .. Appendix E Rle:e:\wp9\5800\5892a.pgl Page 3 GeoSoils, Ine, 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, 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 sen/e as a satisfactory fill material. Fil! 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 materia! 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 ofthe geotechnical consultant in areas designated as suitable for rock disposal. GSI anticipates that soils to be utilized as flll material forthe 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 fi-om 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 wrthin fills, and occurring in cut or natural areas, would need to be disclosed to all interested/afl^ected 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 differentiy 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 Mr. Bruce R. Bartlett — Appendix E File:e:\wp9\5800\5892a.pgi Page 4 GemSmls, Ine^ should be performed three (3) days prior to importation. If any material other than that previously tested is encountered during grading, an appropriate analysis ofthis 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 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 ofthe maximum density as evaluated by ASTM test designation D-1557, or as othenwise recommended by the geotechnical consultant Compaction equipment should be adequately sized and should be specifically designed for soil compaction, or of proven reliability to efficientiy 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, perthe 1997 UBC and/or latest adopted version ofthe California Building Code (CBC), 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 subsequentiy trimming back to the design slope configuration. Testing shall be performed as the flll is elevated to evaluate compaction as the flll core is being developed. Special efforts may be necessary to attain the specifled 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 obsen/ation and/or testing ofthe 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. Mr. Bruce R. Bartlett Appendix E Rle:e:\wp9\5800\5892a.pgi Page 5 GeoSoils, Ine, If an alternative to over-building and cutting back the compacted flll slopes is selected, then special effort should be made to achieve the required compaction in the outer 10 feet of each lift of flll 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. 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 fleld, pending exposed conditions. The location of constructed subdrains, especially the outiets, should be recorded/surveyed bythe 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 Mr. Bruce R. Bartlett Appendix E File:e:\wp9\5800\5892a.pgi Page 6 GemSoits, Ine^ cut slopes should be perfomned. When flll-over-cut slopes are to be graded unless othenwise approved, the cut portion ofthe slope should be observed bythe geotechnical consultant prior to placement of materials for constmction ofthe flll portion ofthe slope. The geotechnical consultant should observe all cut slopes, and should be notified bythe contractor wheh 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. Unless othenwise 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 bythe project civil engineer and should be constructed in compliance with the ordinances ofthe controlling governmental agencies, and/or in accordance with the recommendations ofthe 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 speciflcations. After completion of grading, and after the geotechnical consultant has finished obsen/ations of the work, flnal reports should be submitted, and may be subject to review by the controlling governmental agencies. No further excavation orfilling should be undertaken without prior notification of the geotechnical consultant or approved plans. All flnished cut and fill slopes should be protected fi-om 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 POOUSPA 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 ofthe proposed pool/spa to any slopes with regard to slope creep and lateral fill extension, as well as slope setbacks per code, and geometry ofthe proposed Mr. Bruce R. Bartlett — Appendix E Filc;e.\wpg\5800\5892a.pgi Page 7 Ge€»Soils, Ine, improvements. Recommendations for pools/spas and/or deck flatwork underiain by expansive soils, or for areas with differential settlement greater than y4-inch over 40 feet horizontaiiy, 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 deflned 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 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 (pet) 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 Section 1806.5 of the 1997 UBC. Minimally, the bottoms of the pools/spas, should maintain a distance H/3, where H is the height ofthe slope (in feet), from the slope face. This distance should not be less than 7 feet, nor need not be greater than 40 feet. Mr. Bruce R. Bartlett Appendix E File;e.Awp9\5800\5892a.pg| Page 8 BsmSoitSf Ime. 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 fiil, 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. 8. Ifthe 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 properiy sealed to prevent water ft-om leaking into the adjacent soils materials, and be fitted with slip or expendible 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 underiayment 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 Mr. Bruce R. Bartlett . :jr-p , Appendix E Frle:e:\wp9\5800\5892a.pgi Page 9 GeoSoils, Ine, 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 tiie concrete and minimize the development of unsightly shrinkage cracks. 15. In order to reduce unsightiy 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 ofthe 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 of4,000 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. AH excavations should be observed by a representative ofthe 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 ofthe pool/spa builder. Mr. Bruce R. Bartlett Appendix E File:e:\wp9\5800\5892a.pgi Page 10 GsoSoils, Ineo 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 sitijations which must be avoided to enhance long term performance ofthe pool/spa and associated improvements, and reduce the likelihood of distress. 20. Regardless ofthe 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 tiie pool/spa builder. 21. For pools/spas built within (all or part) of the 1997 Uniform Building Code (UBC) setback and/or geotechnical setback, as indicated in the site geotechnical documents, special foundations are recommended to mitigate the affects of creep, lateral fill extension, expansive soils and settlement on the proposed pool/spa! Most municipalities or County reviewers do not consider these effects in pool/spa plan approvals. As such, where pools/spas are proposed on 20 feet or more of fill, medium or highly expansive soils, or rock fill with limited "cap soils" and built within 1997 UBC 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 underthis 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 ofthe 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, local code, and the 1997 UBC. 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." Mr. Bruce R. Bartlett Appendix E File:e;\wp9\5B00\5892a.pgi Page 11 GeoSoils, Ine, 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 tightiines, 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 ftjrther 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, priorto the placement ofany 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 priorto 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 ofthe 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 tift toward the slope, and may not be esthetically pleasing. The same is true with decking, flatwork and other improvements in this zone. Mr. Bruce R. Bartlett Appendix E Flle:e:\wp9\5800\5892a.pgi Page 12 GeoSmls, Ime^ 30. Failure to adhere to the above recommendations will significantiy 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 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 obsen/ation, 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 regulariy 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 aflixed 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 fleld 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 obsen/es any of our personnel not following the above, we request that it be brought to the attention of our office. Mr. Bruce R. Bartlett Appendix E Rle;e:\wp9\5800\5892a.pgf Page 13 GeoSoils, Ine, 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 traflic. The contractor's authorized representative (supen/isor, 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 shouid 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 ofthe test pit. This zone is established for safety and to avoid excessive ground vibration, which typically decreases test results. When taking slope tests, the technician should park the vehicle directly above or below the test location. If this is not possible, a prominent flag should be placed at the top of the slope. The contractor's representative should effectively keep all equipment at a safe operational distance (e.g., 50 feet) away from the slope during this testing. The technician is directed to withdraw from the active portion of the fill as soon as possible following testing. The technician's vehicle should be parked at the perimeter ofthe fill in a highly visible location, well away fi^om 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 ofthe 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. Mr. Bruce R. Bartlett Appendix E Flle;e:\wp9\5800\5892a.pgl Page 14 GeoSoils, Ine, Trench and Vertical Excavation It is the contractor's responsibilityto provide safe access into fi-enches 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 witfi 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 tiie contractor fails to provide safe access to trenches for compaction testing, our company policy requires that the soil technician withdraw and notify his/her supen/isor. 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 obiigation to notify Cal/OSHA and/or the proper controlling authorities.' Mr. Bruce R. Bartlett ~~ Appendix E nie:e;\wp9\5800\5892a.pgi p^g^ .j^ GeoSoils, Ine, TYPE A Natural grade W7-:- Bedrock or / approved native material Colluvium and alluvium (remove' m^^^yS^ ^— Typical benching See Alternate Details TYPE B Bedrock or approved native material Typical benching See Alternate Details Selection of alternate subdrain details, location, and extent of subdrains should be evaluated by the geotechnical consultant during grading. 7i3''iST""^ CANYON SUBDRAIN DETAIL Plate E-1 6-Inch minimunn 6-inch minirnum 6-Hndi miTHmum A-1 Rlter material: Minimum volume of 9 cubic feet per frieal foot of pipe. Perforated pipe: 6-inch-diameter ABS or PVC pipe or approved substitute with minimum 8 perforations Oi-inch diameter) per lineal foot in bottom half of pipe (ASTM D-2751, SDR-35, or ASTM D-1527, Schd. 40). For continuous run in excess of 500 feet, use 8-inch-diameter pipe (ASTM D-3034, SDR-35, or ASTM D-1785, Schd. 40). -«—6-inch nwwnum FILTER MATERIAL Sieve Size 1 inch % inch % inch No.4 No. 8 No. 30 No. 50 No. 200 Percent Passing 100 90-100 40-100 25-40 18-33 5-15 0-7 0-3 ALTERNATE 1= PERFORATED RPE AND RLTER MATERIAL Fater fabric 6-inch mNmum A-2 6-inch minimum 6-Inch minrnum - Rlter fabric 6-ir)ch minimum B-2 Gravel Materiat 9 cubic feet per lineal foot Perforated Pipe: See Alternate 1 Gravel: Clean %-inch rock or approved substitute. Filter Fabric: Mirafi 140 or approved substitute. ALTERNATE 2= PERFORATED PIPE, GRAVEL, AND FILTER FABRIC CANYON SUBDRAIN ALTERNATE DETAILS Plate E-2 Original ground surface to be restored with compacted Toe of slope as shown on grading plan Compacted. Rll -Original ground surface D = Anticipated removal of unsuitable material (depth per geotechnical engineer) Back-cut varies. For deep removals, backcut should be made no steeper than Id (H^V), or flatter as necessary for safety considerations. Provide a 1=1 (H^V) minimum projection from toe of slope as shown on grading plan to the recommended removal depth. Slope height, site conditions, and/or local conditions could dictate flatter projections. FILL SLOPE TOEING OUT ON FLAT ALLUVIATED CANYON DETAIL Plate E-3 Proposed grade Previously placed, temporary compacted fill for drainage only JL Proposed additional compacted fill Existing compacted UnsuitajDle rn«,terl.al. (to. b^- removed) Bedrock or approved native material To be removed before placing additional compacted fill REMOVAL ADJACENT TO EXISTING FILL ADJOINING CANYON FILL DETAIL Plate E-4 Blanket fll! (If recommended by the geotechnical consultant) Design finish slope Typical benching Typical benching (4-foot minimum) Bedrock or approved native material Subdrain as recommended by geotechnical consultant 4-inch-diameter non-perforated outlet pipe and backdrain (see detail Plate E-6). Outlets to be spaced at 100-foot maximum intervals and shall extend 2 feet beyond the face of slope at time of rough grading completion. At the completion of rough grading, the design civil engineer should provide recommendations to convey any outlet's discharge to a suitable conveyance, utilizing a non-erosive device. G 1# TYPICAL STABIUZATION / BUTTRESS FILL DETAIL Plate E-5 ^ 2-foot ^ mWmum 3 foot mMmum 1 J 4-inch rvmun pipe 2-inch minhium 2-foot minimum Rlter Material: Minimum of 5 cubic feet per lineal foot of pipe or 4 cubic feet per lineal feet of pipe when placed in square cut trench. Alternative in Lieu of Filter Material: Gravel may be encased in approved filter fabric. Filter fabric shall be Mirafi 140 or equivalent. Filter fabric shall be lapped a minimum of 12 inches in all joints. Minimum 4-lnch-Diameter Pipe: ABS-ASTM D-2751, SDR 35; or ASTM D-1527 Schedule 40, PVC-ASTM D-3034, SDR 35; or ASTM D-1785 Schedule 40 with a crushing strength of 1,000 pounds minimum, and a minimum of 8 uniformly-spaced perforations per foot of pipe. Must be installed with perforations down at bottom of pipe. Provide cap at upstream end of pipe. Slope at 2 percent to outlet pipe. Outlet pipe to be connected to subdrain pipe with tee or elbow. Notes: 1. Trench for outlet pipes to be backfilled and compacted with onsite soil. 2. Backdrains and lateral drains shall be located at elevation of every bench drain. First drain located at elevation just above lower lot grade. Addiflonal drains may be required at the discretion of the geotechnical consultant Filter Material shall be of the following specification or an approved equivalent. Sieve Size 1 inch % inch % inch No. 4 No. 8 No. 30 No. 50 No. 200 Percent Passing 100 90-100 40-100 25-40 18-33 5-15 0-7 0-3 Gravel shall be of the following specification or an approved equivalent. Sieve Size 1)^2 inch No. 4 No. 200 Percent Passing 100 50 8 TYPICAL BUHRESS SUBDRAIN DETAIL Plate E-6 Toe of slope as shown on grading plan Natural slope to be restored with compacted fll Proposed grade 2-foot minimum ^In bedrock or i approved I earth material "i Backcut varies Subdrain as recommended by geotechnical consultant NOTES: 1. Where the natural slope approaches or exceeds the design slope ratio, speciai recommendations would be provided by the geotechnical consultant. 2. The need for and disposition of drains should be evaluated by the geotechnical consultant, based upon exposed conditions. FILL OVER NATURAL (SIDEHILL FILL) DETAIL Plate E-7 Typical benching (4-foot minimum) Compacted stablization fill Bedrock or other approved native material It recommended by the geotechnical consultant, the remaining cut portion of the slope may require removal and replacement with compacted fill. Subdrain as recommended by geotechnical consultant NOTES; 1. Subdrains may be required as specified by the geotechnical consultant, 2 W shall be equipment width (15 feet) for slope heights less than 25 feet. For slopes greater than 25 feet, W shall be evaluated by the geotechnical consultant. At no time, shall W be less than H/2, where H is the height of the slope. STABLIZATION FILL FOR UNSTABLE MATERIAL EXPOSED IN CUT SLOPE DETAIL Plate E-9 Proposed finish grade Natural grade Bedrock or approved native material Typical benching (4-foot minimum) 2-foot minimum key depth J 15-toot minimum key width -^^ or H/2 if H>30 feet Subdrain as recommended by geotechnical consultant NOTES: 1, 15-foot minimum to be maintained from proposed finish slope face to backcut. 2. The need and disposition of drains will be evaluated by the geotechnical consultant based on fieid conditions. 3. Pad overexcavation and recompaction should be performed if evaluated to be necessary by the geotechnical consultant. SKIN FILL OF NATURAL GROUND DETAIL Plate E-10 Reconstruct compacted fill slope at 2=1 or flatter (may Increase or decrease pad area) Overexcavate and recompact replacement fill Back-cut varies Natural grade Proposed finish grade Avoid and/or clean up I spillage of materials on the natural slope Bedrock or approved native material Typical benching (4-foot minimum) Subdrain as recommended by geotechnical consultant NOTES: 1. Subdrain and key width requirements will be evaluated based on exposed subsurface conditions and thickness of overburden. 2. Pad overexcavation and recompaction should be performed if evaluated necessary by the geotechnical consultant. DAYLIGHT CUT LOT DETAIL Plate E-11 Natural grade Proposed pad grade Subgrade at 2 percent gradient, drarimg toward street Typical benching Bedrock or approved native material 3- lo 7-foot minhuan* overexcavate and recompact per text of report CUT LOT OR MATERIAL-TYPE TRANSITION Proposed pad grade Natural grade i Subgrade at 2 percent gracOenl, draining toward street V 3- to 7-foot minimum* —' Typical benching material (4-foot minimum) Bedrock or approved native overexcavate and recompact per text of report * Deeper overexcavation may be recommended by the geotechnical consultant in steep cut-fiB transition areas, such that the underlying topography is no steeper than 3:1 (H:V) CUT-FILL LOT (DAYLIGHT TRANSITION) TRANSITION LOT DETAILS Plate E-12 VIEW NORMAL TO SLOPE FACE Proposed finish grade (E)- ^ (E) Hold-down depth ' J5--foc^ ' (SCO <300 (A) -15-foot- mriknum mmvnum (D) ooo(F) ^^^^^^^^^^^^^^^^^^^^ 5-fnr,t I \ /~ Bedrock or approved 5-foot minimum approved native material VIEW PARALLEL TO SLOPE FACE Proposed finish grade (C) 5-foot- minimum Bedrock or approved native material NOTES: A. One equipment width or a minimum of 15 feet between rows (or windrows). B. Height and width may vary depending on rock size and type of equipment. Length of windrow shall be no greater than 100 feei C. If approved by the geotechnical consultant, windrows may be placed direclty on competent material or bedrock, provided adequate space is available for compaction. D. Orientation of windrows may vary but should be as recommended by the geotechnical engineer and/or engineering geologist. Staggering of windrows Is not necessary unless recommended. E. Clear area for utility trenches, foundations, and swimming pools; Hold-down depth aa specified in text of report, subject to governing agency approval. F. All fill over and around rock windrow shall be compacted to at least 90 percent relative compaction or as recommended. G. After fill between windrows is placed and compacted, with the lift of fill covering windrow, windrow should be proof rolled with a D-9 dozer or equivalent. VIEWS ARE DIAGRAMKMTIC ONLY AND MAY BE SUPERSEDED BY REPORT RECOMMENDA"nONS OR CODE ROCK SHOULD NOT TOUCH AND VOIDS SHOULD BE COMPLETELY FILLED OVERSIZE ROCK DISPOSAL DETAIL Plate E-13 ROCK DISPOSAL PITS Fill lifts compacted over rock after embedment I I / I Compacted Fill Granular material 1 I Size of excavation to I be commensurate | with rock size | ROCK DISPOSAL LAYERS Granular soil to fill voids, densified by flooding ^ Compacted fill Layer one rock high Proposed finish grade PROHLE ALONG LAYER * Hold-down depth •* Clear zone TOP VIEW Layer one rock high * Hold-dovKn depth or below towest utility as specified in text of report, subject to governhg agency approval. Clear zone for utility trenches, foundations, and sw'imming pools, as specified in text of report. VIEWS ARE DIAGRAMMATIC ONLY AND MAY BE SUPERSEDED BY REPORT RECOMMENDATIONS OR CODE ROCK SHOULD NOT TOUCH AND VOIDS SHOULD BE COMPLETELY FILLED IN ROCK DISPOSAL DETAIL Plate E-14 5-foot-high impact/debris wall METHOD 1 Pad grade Existing grade ^^^^ 5-foot-high impact/debris wall METHOD 2 Pad grade Existing grade 5-foot-wide catchment area 5-foot-high mpact/debris wall METHOD 3 Pad grade Existing grade Fence 2:1 (h:v) slope METHOD 4 Pad grade NOT TO SCALE DEBRIS DEVICE CONTROL METHODS DETAIL Plate E-15 Rock-filled gabion basket 5-foot mWmum or as recorwnended by geotectmical consultant Proposed grade Filter fabric Drain rock Compacted fill Gabion impact or diversion wall should be constructed at the base of the ascending slope subject to rock fall. Walls need to be constructed with high segments that sustain impact and mitigate potential for overtopping, and low segment that provides channelization of sediments and debris to desired depositional area for subsequent clean-out. Additional subdrain may be recommended by geotechnical consultant. From GSA. 1987 ROCK FALL MITIGATION DETAIL Plate E-16 MAP VIEW NOT TO SCALE SEE NOTES B Top of slope Concrete cut-off wall 4-inch perforated subdrain pipe (transverse) B' Gravity-flow, nonperforated subdrain pipe (transverse) Toe of slope < 4-inch perforated subdrain pipe (longitudinal) Direction of drahage CROSS SECTION VIEW NOT TO SCALE SEE NOTES 2-inch-lhick sand layer Gravity-flow norperforated—^Concrete subdrain pipe cut-off wall- 2-inch-thick sand layer Vapor retarder Perforated subdrari pipe NOTES: 1. 3. 6-inch-thick, clean gravd (% to tJ^ inch) sub-base encapsulated in Mirafi 140N or equivalent, underlain by a 15-mil vapor retarder, with 4-inch-diameter perforated pipe longitudinal connected to 4-inch-diameter perforated pipe transverse. Connect transverse pipe to 4-inch-diameter nonperforated pipe at low point and outlet or to sump pump area. Pools on fills thicker than 20 feet shouid be constructed on deep foundations; otherwise, distress (tilting, cracking, etc.) should be expected. Design does not appiy to infinity-edge pools/spas. TYPICAL POOL/SPA DETAIL Plate E-17 Finish grade %-inch-diameter X 6-inch-long carriage bolt or equivalent 6-Inch diameter X Sj^-inch-long hole Concrete backflll Gi6% TYPICAL SURFACE SETTLEMENT MONUMENT Plate E-19 Geotechnical • Geologic • Coastal • Environmental 5741 Palmer Way • Carlsbad, California 92010 • (760)438-3155 • FAX (760) 931-0915 October 23, 2009 W.O. 5892-A-SC Mr. Bruce R. Bartlett c/o Esbensen Architecture 6150 Yarrow Drive, Suite H Garlsbad, California 92009 Attention: Mr. Dennis Moore Subject: Geotechnical Plan Review, Green Dragon Tavern and Museum, 6115 Paseo Del Norte, City of Carisbad, San Diego County, California Dear Mr. Bartlett: In accordance with a request from Esbensen Architecture, and in response to plan check comments from the Esgil Corporation ([Esgil], 2009 [see the Appendix]), GeoSoils, Inc. (GSI) has performed a review of our geotechnical report (GSI, 2009), the foundation plans and details prepared by Esbensen & Associates ([E&A], 2009), and the grading and improvement plans prepared by O'Day Consultants ([ODC], 2009a, 2009b) for the purpose of evaluating if the plans are in general conformance with the intent of the geotechnical report (GSI, 2009). GSI's scope of services included a review ofthe referenced reports and plans, analysis of data, and preparation of this summary letter. The conclusions and recommendation presented in GSI (2009) are considered valid and applicable with respect to the subject site, and should be properly incorporated into the design and construction phases of site development, unless specifically superceded in the text of this review document. PLAN REVIEW Grading Plans Based on our review, our recommendations (GSI, 2009) generally appear to have been properly incorporated into the plans (O'Day, 2009a). As such, the plans generally appear suitable from a geotechnical standpoint, with the following comments, and/or additional recommendations. For Clarity, Engineer's Note No. 6, shown on Sheet 1 of O'Day (2009a) should include the work order and date ofthe geotechnical report as follows: "as described in the retaining wall section of the soils report by GeoSoils," (add) work order 5892 A-SC, dated June 30, 2009. Section C-C, D-D, E-E, and F-F, shown on Sheet 2 of O'Day (2009a) should also indicate that the "gravel" shall be encapsulated in a filter fabric (mirafi 140 N, or equivalent). The gradational requirements for the gravel should also be indicated. "Engineered Soil," indicated on Sections C-C, D-D, E-E, and F-F of O'Day (2009a) should consist of a relatively permeable, granular soil with a minimum sand equivalent (SE) of 25 and be compacted to a minimum relative compaction of 90 percent per ASTM D-1557. As onsite soils contain variable amounts of clay, a select import, or stockpiling of available, select onsite soil (if any) should be anticipated. The gravel underdrain systems (see Sections C-C, D-D, E-E, and F-F on Sheet 2 of O'Day [2009a]) should remain above a 1:1 projection down and away from any adjacent, settlement sensitive improvement. Alternatively, the affected improvement may be deepened to at least 6 inches below the gravel layer, or to the top of formational soil, whichever is deeper. "Enhanced pavements" shown on Sheets 1 and 3 of O'Day (2009a) were indicated on these plans as being a part of the landscape plans for the project. At this time, the landscape plans were not available for review by this office. A geotechnical review of the "enhanced pavement" sections should be performed prior to construction, and preferably in the planning stage. Grading Note #36, shown on Sheet 2 may be completed as follows: "The Soils Report Titied" Preliminary Geotechnical Investigation, Proposed Green Dragon Colonial Village (Formerly Hadley's), Paseo Del Norte, Carlsbad, San Diego County, California "Prepared By" GeoSoils, Inc. Work Order No. 5892-A-SC. "Dated" June 30, 2009 The "Note:" indicated with respect to preliminary pavement sections, shown on Sheet 4 of O'Day (2009a) should be revised to indicate that actual pavement thickness to be determined by R-vaiue tests performed upon the completion of grading. Bus pads and trash enclosures should be designed and constructed per the minimum City Standards. Mr. Bruce Bartlett W.O. 5892-A-SC 6115 Paseo Del Norte, Garlsbad October 23, 2009 File:e:\wp9\5800\5892a.gpr Page 2 GeoSmls, Ine, GSI has assumed that trench re-surfacing during the improvement of Paseo Del Norte will be perfonned per City Standards, and pavement section minimally matched in kind. Therefore, no further pavement design/laboratory testing is deemed necessary, based on this condition. Improvement Plans Based on our review, our recommendations (GSI, 2009) generally appear to have been properiy incorporated into the plans (O'Day, 2009b). Again, the plans generally appear suitable from a geotechnical standpoint, with the following comments, and/or additional recommendations. Water note #7, shown on Sheet 1 of O'Day (2009b) discusses "soil tests" as they relate to soil corrosion potential. Testing to evaluate the corrosion potential of site soils has been performed, and is presented in GSI (2009). Additional testing of site soil may be performed if requested. GSI assumes that cathodic protection of utilities as indicated on the plans, is a requirement ofthe City, and was thus not discussed in our geotechnical report. Foundation Plans and Details Based on our review, the plans reviewed (E&A, 2009) generally appear suitable from a geotechnical standpoint, with the following comments, and/or additional recommendations. Per Plan Check Comment #23 (structural), seismic design data to be provided on the plans is included in GSI (2009). In order to reduce any misunderstanding between the plans and the content of the geotechnical report, our report (GSI, 2009) should be referenced on the plans (E&A, 2009). Foundation Note 7 indicates a minimum slab thickness of 4 inches. This should be revised to a minimum of 5 inches per GSI (2009). Foundation Note 7 should also include a reference to GSI (2009). The current edition of the California Building Code (California Building Standards Commission, 2007) should be cited on the plans. The "existing" footing depths indicated, and/or implied on the plans (see Sheet S7, Detail 51,52, and Sheet S8, Detail 67) were not provided by GSI. The plans should cite the applicable reference regarding existing footing depths/widths. If existing footing depths are generally unknown at this time, all depths indicated for new Mr. Bruce Bartlett W.O. 5892-A-SG 6115 Paseo Del Norte, Garlsbad October 23, 2009 Rle-.e:\wp9\5800\5892a.gpr Page 3 GeoSoils, Ine, foundations on the plans are considered minimums and may need to be deepened, based on the conditions exposed during construction. The slab designer should review the "Soil Moisture Considerations" section in GSI (2009) for further criteria with regard to moisture transmission and slab underiayment. If moisture sensitive areas within the structure are planned, a retrofit ofthe existing slab may be considered. This may include removal and replacement of slabs, and/or slab surface treatments, as necessary, if a lower level of moisture vapor transmission is desired. The foundation depths shown on the plans are considered as minimums only. New footings to be located in areas where remedial grading is not performed (i.e., existing building interior, etc.) will likely need to be deepened to encounter suitable bearing soil, based on the soil conditions exposed within the foundation excavation. Underpinning may be performed on the existing foundation where new structural loads are significantly higher than for existing, and the bearing capacity would be exceeded. Underpinning should be reviewed when column loads are provided. The underpinning should be perfonned in sections (perthe designer) such thatthe un-supported condition of the existing footing may be tolerated by the existing foundation system, without distress. The methods used or planned should be provided by the designer. SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING We recommend that observation and/or testing be performed by GSI at each of the following construction stages: • During grading/recertification. During significant excavation (i.e., higher than 4 feet). During placement of subdrains, toe drains, or other subdrainage devices, prior to placing fill and/or backfill. After excavation of building footings, retaining wall footings, and free standing walls footings, prior to the placement of reinforcing steel or concrete. 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 retarders (i.e., visqueen, etc.). Mr. Bruce Bartlett W.O. 5892-A-SC 6115 Paseo Del Norte, Garlsbad October 23, 2009 File;e:\wp9\5800\5892a.gpr ^ m "v w Paae 4 Ge&S&tts, Ine, ^ During retaining wall subdrain installation, priorto backfill placement During placement of backfill for area drain, interior plumbing, utility line trenches and retaining wall backfill. During slope construction/repair. When any unusual soil conditions are encountered during any construction operations, subsequent to the issuance ofthis report. When any improvements, such as flatwork, spas, pools, walls, etc., are constructed. A report of geotechnical obsen/ation and testing should be provided at the conclusion of each of the above stages, in order to provide concise and clear documentation of site work, and/or to comply with code requirements. OTHER DESIGN PROFESSIONALS/CONSULTANTS The design civil engineer, structural engineer, 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. 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. Ifthe structural engineer/designer has any questions or requires further assistance, they should not hesitate to call or othenwise transmit their requests to GSI. ADDITIONAL PLAN REVIEW Any additional revisions to the plans reviewed herein, or any new plans, should be reviewed by this office prior to construction, so that construction is in accordance with the conclusions and recommendations of this report. Based on our review, supplemental recommendations and/or further geotechnical studies may be warranted. Mr. Bruce Bartlett ~ " W.O. 5892-A-SG 6115 Paseo Del Norte, Carlsbad October 23 2009 File:e:\wp9\5800\5892a.gpr m it Panp S LIMITATIONS The materials encountered on the project site and utilized for our analysis are believed representative ofthe area; however, soil and bedrock materials vary in character between excavations and natural outcrops or conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors. Inasmuch as our study is based upon our review and engineering analyses and laboratory data, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty is express or implied. 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 sen/ices for this portion of the projecL The opportunity to be of sen/ice is greatly appreciated. If you have any questions concerning this report, or if we may be of further assistance, please do not hesitate to contact any of the undersigned. Respectfully submitte GeoSoils, Inc. Robert G. Crisman Engineering Geologi RGC/ATG/JPF/jh /Andrew T Guatelli Geotechnical Engineer, Attachment: Appendix - References Distribution: (4) Addressee Mr. Bruce Bartlett 6115 Paseo Del Norte, Carlsbad Fl)e.e:\wp9\5800\5892a.gpr GeoSoils, Ine, W.O. 5892-A-SG October 23, 2009 Page 6 APPENDIX REFERENCES California Building Standards Commission, 2007, California building code. Esbensen & Associates, 2009. Foundation plan and details for: Green Dragon tavem and museum, colonial village, 6115 Paseo Del Norte, Carlsbad, Ca 92011 1/8 inch scale, Sheets S2, S5, S6, S7, and S8, CUP 08-08, CDP 08-13, no job No dated September 11. ^ -. Esgil Corporation, 2009, Plan Check Comments for: Proposed Green Dragon Colonial Village (Formerly Hadley's), Paseo Del Norte, Carisbad, San Diego County California, City of Carisbad Plan Check 091499, dated September 28. GeoSoils, Inc., 2009, Preliminary geotechnical investigation, proposed Green Dragon Colonial Village (formeriy Hadley's), Paseo Del Norte, Carlsbad, San Diego Countv California, W.O. 5892-A-SC, dated June 30. ^ y O'Day Consultants, 2009, Grading plans for: Green Dragon Colonial Village 20 scale Sheets 1 through 4, Job No. 081240, print dated September 10. , 2009b, Improvement plans for: Green Dragon Colonial Village, 20 scale Sheets 1 through 5, Job No. 081240, print dated September 10. GeoSoils, Ine,