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HomeMy WebLinkAboutCT 15-06; THE WAVE; PRELIMINARY GEOTECHNICAL EVALUATION; 2015-11-03,C I I I I I I I I I I E [ ' I I I I [ PRELIMINARY GEOTECHNICAL EVALUATION ''THE " STAT A W.O. 6935-A-SC NOVEMBER 3, 2015 • NOV 2 4 2015 CITY Gt= C. .'. 1 _.? .. D PL,." , .) _), /C ·~,;\ ;--• • w I < • • ~ - I I I I I I I I I I I I [ I I I I I I • Geotechnical • Geologic • Coastal • Environmental 26590 Madison Avenue • Murrieta, California 92562 • (951) 677-9651 • FAX (951) 677-9301 • www.geosoilsinc.com November 3, 2015 W.0. 6935-A-SC Mr. Michael Donovan 4629 Cass Street, Suite 255 San Diego, California 92109 Subject: Geotechnical Evaluation, "The Wave," 2646 State Street, Carlsbad, San Diego County, California Dear Mr. Donovan: In accordance with your request and authorization, GeoSoils, Inc. (GSI) is pleased to present the results of our preliminary geotechnical evaluation of the subject site. The primary purpose of our study was to evaluate the onsite geologic and geotechnical conditions as they pertain to the proposed mixed-use development thereon, and to develop recommendations for site earthwork and the design of foundations, walls, and pavements. EXECUTIVE SUMMARY Based upon our field exploration, geologic, and geotechnical engineering analysis, the proposed mixed-use development appears feasible from a geotechnical engineering and geologic viewpoint, provided that the recommendations presented in the text of this report are properly incorporated into the design and construction of the project. The most significant elements of our study are summarized below: • • In general, the site may be characterized as being mantled by a thin veneer of undifferentiated, Quaternary-age colluvium and undocumented fill. These surficial earth units are immediately underlain by Quaternary-age old paralic deposits (formerly termed "terrace deposits") extending to depths on the order of 1 O to 12 feet below the existing grades. Below these depths, Eocene-age sedimentary bedrock, belonging to the Santiago Formation occurs. Due to their relatively low density and lack of uniformity, all surficial deposits of colluvium, undocumented fill, and potentially near surface weathered old paralic deposits, are considered unsuitable for the support of settlement-sensitive improvements (i.e., foundations, concrete slab-on-grade floors, site walls, exterior hardscape, etc.) and/or planned fills in their existing state. Based on the available data, the thickness of these soils across the site is anticipated to be on the order of 2 feet to 4 feet. However, localized thicker sections of unsuitable soils cannot be precluded, and should be anticipated. Conversely, the underlying unweathered old I I I I I I I I I I I [ [ I I I I I I • • • • • paralic deposits {previously referred to as "terrace deposits") and Santiago Formation (at depth) are generally considered suitable for the support of settlement-sensitive improvements and/or engineered fill. It is anticipated that the potentially compressible surficial deposits will generally be removed by default during excavation to design grade for the basement section. Undercutting/over excavation of paralic deposits will be necessary for support of ground floor portions of the structure. Slot cuts should be anticipated in order to complete remedial removals and over excavation adjacent to settlement-sensitive improvements to remain. GSI anticipates that due to the nature of the subsurface earth materials and the location of adjacent developments/improvements, the below grade improvements and grading will likely require either: (a) permanent or temporary shoring, and/or (b) slot cuts to complete the installation and construction. GSI has considered the design alterllt!tives including isolated spread/continuous footings and mat foundations for support of the proposed building upon a recompacted fill subgrade. Seme site soils are expansive and should be considered in foundation design and construction. It should be noted that the 2013 California Building Code ([2013 CBC], California Building Standards Commission [CBSC], 2013) indicates that removals of unsuitable soils be performed across all areas to be graded, under the purview of the grading permit, not just withinthe influence of the proposed building. 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 or offsite. Thus, any settlement-sensitive improvements (walls, curbs, flatwork, etc.), constructed within this zone may require deepened foundations, reinforcement, etc., or will retain some potential for settlement and associated distress. This will also require proper disclosure to any owners and all interested/affected parties should this condition exist at the conclusion of grading. Expansion Index (E.I.), and plasticity index (P .I.) testing performed on representative samples of the onsite soil indicates E.l.s ranging from less than 20 (very low expansive) to 73 (medium expansive), and a Plasticity Index (P.I.) of up to 26. As such, some site soil (primarily the upper portion of old paralic deposits) meet the criteria of detrimentally expansive soils as defined in Section 1803.5.2 of the 2013 CBC. Soil expansivity should be re-evaluated atthe conclusion of grading and provide updated data for final foundation design. Corrosion testing performed on a representative sample of the onsite soils indicates site soils are mildly alkaline with respect to soil acidity/alkalinity; are corrosive to severely corrosive to exposed buried metals wherf~urated; present negligible to moderate sulfate exposure to concrete (per ACI 318-11); and contain concentrations of soluble chlorides below action levels. It should be noted that GSI Mr. Michael Donovan File:e:\wp 12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC Page Two I I I I I I I I I I I D D E m I I I I • • • • • does not consult in the field of corrosion engineering. Thus, the client, project architect, and project structural engineer should agree on the level of corrosion protection required for the project and seek consultation from a qualified corrosion consultant as warranted, especially in light of the site's proximity to the Pacific Ocean, which is a corrosive environment, and the potential fpr water to perch within earth materials with contrasting permeabilities and/or densities. A perched groundwater table was encountered at depths of approximately 12 feet below existing surface grades onsite. Based on a review of ground surface elevations provided on MAA (2015), this equates to an approximate elevation of 27% feet MSL. Groundwater is not anticipated to significantly affect the proposed development. However, the perched groundwater table may present difficulties in the form o1 caving soils, and/or seepage during excavations for shoring, foundations, and underground utilities if completed in proximity of the elevations noted above. The need for dewatering cannot entirely be precluded. Perched water may also occur in the future along zones of contrasting permeabilities and/or density if the site is subjective to rainfall of a significant intensity and duration during and after construction. This potential should be disclosed to all interested/affected parties. Below-grade moisture around the parking garage and/or elevator pit will likely require a permanent sump, should wall backfill accumulate water or surface water enter the garage. Moisture vapor control in the garage slab will reduce transmission of water vapor and the potential for moisture to damage storage, equipment, or vehicles. The currently planned development includes planned excavations up to approximately 12 to 14 feet in close proximity to adjacent property and structures. Where planned excavations do not allow for the temporary slopes, recommended herein, a properly designed shoring system will be necessary. Recommendations for temporary and permanent shoring systems are provided herein. Our evaluation indicates there are no known active faults crossing the site and the natural slope upon which the site is located has very low susceptibility to deep-seated landslides. Owing to the depth to groundwater and the dense nature of the old paralic deposits and underlying Santiago Formation, the potential for the site to be adversely affected by liquefaction/lateral spreading is considered very low. Site soils are considered erosive. Thus, properly designed site drainage is necessary in reducing erosion damage to the planned improvements. The seismic acceleration values and design parameters provided herein should be considered during the design of the proposed development. The adverse effects of seismic shaking on the structure(s) will likely be wall cracks, some foundation/slab distress, and some seismic settlement. However, it is anticipated that the structure will be repairable in the event of the design seismic event. This potential should be disclosed to any owners and all interested/affected parties. Mr. Michael Donovan File:e:\wp12\6900\6942a.g~f GeoSoils, Inc. W.O. 6935-A-SC Page Three ------------------------------------~------------ I I I I I I I I I I I D I I I I I • Additional 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. The opportunity to be of service is sincerely appreciated. If you should have any questions, please do not hesitate to contact our office. GeoSoils, Inc. Robert G. Crisman Engineering Geologist, CEG 1934 RGC/DWS/JPF/jh Distribution: (4) Addressee Mr. Michael Donovan File:e:\wp 12\6900\6935a.gef ~~ Civil Engineer, RCE 47857 GeoSoils, Inc. W.O. 6935-A-SC Page Four I I I I I I I I I I I [ [ I I I I I I TABLE OF CONTENTS SCOPE OF SERVICES ................................................... 1 SITE DESCRIPTION AND PROPOSED DEVELOPMENT ......................... 1 FIELD STUDIES ......................................................... 3 REGIONAL GEOLOGY ................................................... 3 SITE GEOLOGIC UNITS .................................................. 4 Undocumented Fill (Not Mapped) ..................................... 4 Quaternary-age Colluvium (Not Mapped) ............................... 4 Quaternary-age Old Paralic Deposits (Map Symbol -Qop) ................. 4 Tertiary-age Santiago Formation (Map Symbol -Tsa) ..................... 5 Structural Geology ................................................. 5 GROUNDWATER ........................................................ 5 MASS WASTING/LANDSLIDE SUSCEPTIBILITY ............................... 6 FAULTING AND REGIONAL SEISMICITY ..................................... 6 Local and Regional Faults ........................................... 6 Seismicity ........................................................ 7 Deterministic Maximum Credible Site Acceleration .................. 7 Historical Site Acceleration ..................................... 7 Seismic Shaking Parameters ......................................... 8 LIQUEFACTION POTENTIAL .............................................. 9 Liquefaction ...................................................... 9 Seismic Densification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 O Summary ........................................................ 10 Other Geologic/Secondary Seismic Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 SUBSIDENCE ......................................................... 11 SLOPE STABILITY ...................................................... 11 EXCAVATION CHARACTERISTICS ........................................ 11 LABORATORY TESTING ................................................. 11 Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Laboratory Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Expansion Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Atterberg Limits ................................................... 12 Direct Shear Test ................................................. 13 GeoSoils, Inc. I I I I I I I I I I ! c: c: ll I I I I E Consolidation Test ................................................ 13 Saturated Resistivity, pH, and Soluble Sulfates, and Chlorides ............. 13 Corrosion Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS .................... 14 EARTHWORK CONSTRUCTION RECOMMENDATIONS ....................... 17 General ......................................................... 17 Construction Phasing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Preliminary Earthwork Factors (Shrinkage/Bulking) ...................... 17 Demolition/Grubbing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Treatment of Existing Ground/Remedial Grading ........................ 18 Overexcavation ," . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Fill Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Subdrains ....................................................... 20 Temporary Slopes ................................................ 20 Import Fill Materials ............................................... 20 PRELIMINARY RECOMMENDATIONS -FOUNDATIONS ....................... 20 General ......................................................... 20 Expansive Soils ................................................... 21 Preliminary Conventional Foundation Design ........................... 21 PRELIMINARY CONVENTIONAL FOUNDATION CONSTRUCTION RECOMMENDATIONS ............................................................... 24 Preliminary Mat Foundation Recommendations ......................... 25 Mat Foundation Design ............................................ 25 Mat Foundation Vertical Bearing ............................... 26 Mat Foundation Lateral Resistance ................................... 26 Subgrade Modulus and Effective Plasticity ............................. 26 Other Structural Considerations for Mat-Type Foundations ................ 27 Corrosion and Concrete Mix ........................................ 27 SOIL MOISTURE TRANSMISSION CONSIDERATIONS ........................ 27 RETAINING WALL DESIGN PARAMETERS .................................. 29 General ......................................................... 29 Conventional Retaining Walls ....................................... 30 Preliminary Retaining Wall Foundation Design .................... 30 Restrained Walls ............................................ 31 Cantilevered Walls ........................................... 31 Seismic Surcharge ................................................ 32 Retaining Wall Backfill and Drainage .................................. 33 Wall/Retaining Wall Footing Transitions ............................... 37 Mr. Michael Donovan, Inc. File:e:\wp12\6900\6935a.gef GeoSoils, Inc. Table of Contents Page ii ,,__,___,. __ .......... ___________________________________ _ I I I I I I I I I I [ [ [ [ E I I I I SHORING WALLS ...................................................... 37 Shoring of Excavations ............................................. 37 Lateral Earth Pressures for Shoring Design ............................ 38 Shoring Vertical Bearing -Temporary and Permanent Walls ............... 41 Tie-Backs Anchors ................................................ 42 Shoring Construction Recommendations .............................. 42 Alternating Slot Excavations ........................................ 43 Monitoring of Shoring .............................................. 43 Monitoring of Structures Prior to, During, and Post-Shoring Construction and Excavation ........... · ................................ 44 PRELIMINARY PORTLAND CEMENT CONCRETE PAVEMENT (PCCP) DESIGN RECOMMENDATIONS ............................................. 45 PORTLAND CEMENT CONCRETE (PCC) FLATWORK AND OTHER IMPROVEMENTS ............................................................... 46 ONSITE INFILTRATION-RUNOFF RETENTION SYSTEMS ...................... 48 General ......................................................... 48 DEVELOPMENT CRITERIA ............................................... 52 Drainage ........................................................ 52 Erosion Control ................................................... 53 Landscape Maintenance ........................................... 53 Gutters and Downspouts ........................................... 53 Subsurface and Surface Water ...................................... 53 Site Improvements ................................................ 54 Tile Flooring ..................................................... 54 Additional Grading ................................................ 54 Footing Trench Excavation ......................................... 54 Trenching/Temporary Construction Backcuts .......................... 55 Utility Trench Backfill .............................................. 55 SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING ........................................................ 55 OTHER DESIGN PROFESSIONALS/CONSULTANTS .......................... 56 PLAN REVIEW ......................................................... 57 LIMITATIONS .......................................................... 57 Mr. Michael Donovan, Inc. File:e:\wp 12\6900\6935a.gef GeoSoils, Inc. Table of Contents Page iii I I I I I I I I I I I E D D I I I I I FIGURES: Figure 1 -Site Location Map ......................................... 2 Detail 1 -Typical Retaining Wall BackfiH and DrainageOetail .............. 34 Detail 2 -Retaining Wall Backfill and Subdrain Detail Geotextile Drain ....... 35 Detail 3 -Retaining Wall and Subdrain Detail Clean Sand Backfill ........... 36 Figure 2 -Lateral Earth Pressures for Temporary Shoring Systems ......... 39 Figure 3 -Lateral Earth Pressures for Permanent Shoring Systems ......... 40 ATTACHMENTS: Plate 1 -Geotechnical Map ................................. Rear of Text Appendix A-References ................................... Rear of Text Appendix B -Borings Logs ................................. Rear of Text Appendix C -Seismicity Data ................................ Rear of Text Appendix D -Laboratory Data ............................... Rear of Text Appendix E -General Earthwork and Grading Guidelines ......... Rear of Text Mr. Michael Donovan, Inc. File:e:\wp12\6900\6935a.gef GeoSoils, Inc. Table of Contents Page iv I I I I I I I I I I I E D D GEOTECHNICAL EVALUATION FOR THE "WAVE," 2646 STAT~ STREET CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA SCOPE OF SERVICES The scope of our services has included the following: 1. Review of readily available published literature, aerial photographs, and maps of the vicinity (see Appendix A), including proprietary in-house geologic/geotechnical reports for this site. 2. 3. 4. 5. 6. 7. Site reconnaissance mapping and the excavation of three (3) hollow-stem auger borings to evaluate the soil/bedrock profiles, sample representative earth materials, and delineate the horizontal and vertical extent of earth material units (see Appendix B). General geologic/seismic hazards evaluation. Areal seismicity evaluation (see Appendix C). Appropriate laboratory testing of relatively undisturbed and representative bulk soil samples collected during our geologic mapping and subsurface exploration program (see Appendix D). Anafysts of field and laboratory data relative to the proposed development. Appropriate engineering and geologic analyses of data collected, and the preparation of this summary report and accompaniments. SITE DESCRIPTION AND PROPOSED DEVELOPMENT The subject site consists of a rectangular shaped, vacant property located on the northeast side of State Street, midway between the intersections of Beech Avenue and State Street, and Laguna Avenue and State Street, in Carlsbad, San Diego County, California (see Figure 1, Site Location Map). The property is bounded by State Street to the northeast, and existing mobile home park to the northwest, and commercial/residential property to the southwest. Topographically, the site is relatively flat lying, at an approximate elevation of about 39 to 40 feet (MSL), according to a topographical plan prepared by MM Design Group (MM, 2015). Site drainage appears to be directed toward State Street via sheet flow. Vegetation consists of scattered gasses, and a large tree, located at the rear (northeast) end of the site. GeoSoils, Inc. Base Map: TOPO!® ©2003 National Geographic, U.S.G.S. San Luis Rey Quadrangle, California --San Diego Co., 7.5 Minute, dated 1997, current, 1999. Carlsbad Base Map: Google Maps, Copyright 2015 Google, Map Data Copyright 2015 Google w.o. This map is copyrighted by Google 2015. It is unlawful to copy or reproduce all or any part thereof, whether for personal use or resale, without pennission. All rights reserved. 6935-A-SC SITE LOCATION MAP N Figure 1 I I I I I I I I I I I I I I I I I I I Existing improvements consist of a small, single-family residential structure, located within the central portion of the site. A low height masonry wall is located along the northwestern and northeastern property line, with an existing commercial building located within the adjacent property to the southeast, situated along the southeast property line. Based on our review of architectural drawings prepared by MAA Design Group (MAA, 2015), development will consist of site preparation for the construction of a five-level, multi-family residential structure, consisting of one basement level parking area, a street level parking/retail area, with three (3) floors of residential above. Excavation depths for the basement level are anticipated to be on the order of 12 to 14 feet below existing grades. FIELD STUDIES Site-specific field studies were conducted by GSI in late August 2015, and consisted of reconnaissance geologic mapping and advancing three (3) exploratory hollow-stem auger borings with a truck-mounted drill rig, for an evaluation of the site's near-surface soil and geologic conditions. The borings were logged by a representative of this office who collected representative bulk and relatively undisturbed soil samples for appropriate laboratory testing. The logs of the borings are presented in Appendix B. The approximate location of the borings are presented on the Geotechnical Map (see Plate 1), which uses MAA (2015) as a base. REGIONAL GEOLOGY The subject property lies within the coastal plain physiographic region of the Peninsular Ranges Geomorphic Province of southern California. This region consists of dissected, mesa-like terraces that transition inland to rolling hills. The encompassing Peninsular Ranges Geomorphic Province is characterized as elongated mountain ranges and valleys that trend northwesterly (Norris and Webb, 1990). This geomorphic province extends from the base of the east-west aligned Santa Monica -San Gabriel Mountains, and continues south into Baja California. The mountain ranges within this province are underlain by basement rocks consisting of pre-Cretaceous metasedimentary rocks, Jurassic metavolcanic rocks, and Cretaceous plutonic (granitic) rocks. In the Southern California 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 during the Tertiary Period (Eocene-age) into the narrow, steep, coastal plain and continental margin of the basin. 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. Regional geologic mapping by Kennedy and Tan (2005) indicate the site is underlain by Quaternary-age old paralic deposits (formerly termed "terrace deposits"), which is considered bedrock, or Mr. Michael Donovan 2646 State Street, Carlsbad File:e,\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 3 I I I I I I I I I I [ i' I I I I I formational soil, at the site. Older sedimentary rocks belonging to the Eocene-age Santiago Formation underlie the old paralic deposits. SITE GEOLOGIC UNITS The site geologic units observed and/or encountered during our subsurface investigation and site reconnaissance included undifferentiated Quaternary-age colluvium, Quaternary-age old paralic deposits, and the underlying Tertiary Santiago Formation. The onsite earth units are generally described below from the youngest to the oldest. The distribution of these geologic units is shown on Plate 1 . Undocumented Fill (Not Mapped) A local area of undocumented fill was observed in the vicinity of Boring 8-2. This earth material generally consisted of dark brown, silty sand, with concrete/brick debris, typically observed to be slightly moist and loose. The undocumented fill was observed to extend to depths on the order of about 4 feet below the existing grades, with its distribution likely localized in the immediate vicinity of the boring, based on field observations. Undocumented fill is considered potentially compressible in its existing state. Removal and recompaction of these earth materials are recommended for uniform support of settlement-sensitive improvements and planned fills if they are not removed by the planned excavations. Quaternary-age Colluvium (Not Mapped) A thin mantle of undifferentiated Quaternary-age colluvium was encountered atthe surface in two of the three borings. This earth material generally consisted of dark brown to brown, silty sand, typically observed to be dry and loose. The colluvium was observed to extend to depths on the order of 1 % to 2 feet below the existing grades. Colluvium is considered potentially compressible in its existing state. Removal and recompaction of these earth materials are recommended for uniform support of settlement-sensitive improvements and proposed fills, if they are not removed by the planned excavations Quaternary-age Old Paralic Deposits (Map Symbol -Qop) Quaternary-age old paralic deposits were observed underlying the colluvium and undocumented fill onsite, at depths ranging from about 1 % to 4 feet below the existing grade. As observed, old paralic deposits within about 6 feet from existing grades generally consisted of a dark brown, sandy clay, typically observed to be moist to wet, and very stiff. At a depth of about 6 feet, paralic deposits grade to a light olive brown to dark grayish brown, clayey sand, typically observed to be wet, and dense. Underlying the clayey sand layer, at depths on the order of 6% to 7% feet, old paralic deposits become light brown to brown, wet and dense sand, and wet and dense gravelly sand, grading downward into a basal layer of cobbles and gravelly sand along the underlying contact with Eocene-age, Mr.Michael Donovan 2646 State Street, Carlsbad File:e:\wp 12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 4 "" J J J I I I sedimentary bedrock. The basal contact is at a depth of about 1 Oto 12 feet below existing surface grade. Old paralic deposits are considered suitable bearing materials. However, remedial earthwork, in the form of undercutting and recompaction of near surface materials is anticipated, based on the planned construction. Tertiary-age Santiago Formation (Map Symbol -Tsa) As observed in the borings, Eocene-age sedimentary bedrock, belonging to the Santiago Formation, underlies the old paralic deposits at approximate depths of 1 O to 12 feet below the existing grade. The Santiago Formation generally consisted of a light olive brown to brownish gray sandstone, becoming a light olive brown to light olive gray clayey sandstone at a depth of approximately 25 feet below surface grades. The Santiago Formation was typically observed to be wet and dense near the contact with the overlying old paralic deposits, becoming moist with depth. The Santiago Formation is considered suitable for support of settlement-sensitive improvements and/or planned fills in its existing state. Structural Geology Based on our experience in the site vicinity, bedding within Quaternary-age old paralic (terrace) deposits is typically thick, and generally flat lying to gently westerly dipping. The geologic contact between the old paralic deposits and Santiago Formation consists of an ancient wave-cut platform that slightly dips in a westerly direction. Regional geologic mapping by Kennedy and Tan (2005) indicates Santiago Formation bedding is inclined on the order of 10 degrees in a northeasterly direction, in the site vicinity. GROUNDWATER Regional groundwater is expected to generally be coincident with sea level (Mean Lower Low Water [MLLW]) or approximately 48 feet below the lowest site elevation. A perched groundwater table was encountered in Borings B-1 and B-2 along the contact between the younger "old" paralic deposits, and the underlying Santiago Formation, at an approximate depth of 1 Oto 12 feet below existing surface grade, or at an elevation of about 27 to 30 feet MSL. This perched groundwater table will likely be encountered during excavation for the lowermost garage level of the structure, and will need to be considered during construction and may present difficulties during construction in the form of saturated soils and caving/sloughing excavations. As such, a mechanical sump will likely be necessary during construction and incorporated into the design of the structure. Further, the presence of perched water increases the potential for vapor or water transmission through the slab, foundations, and subterranean walls. Footings will need to be placed on firm, unyielding soils with no standing groundwater and therefore, some pumping/dewatering could be necessary. Supplemental evaluations with respect to groundwater levels could be performed during future design phase work. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 5 I I I I I I I I I I I I ii ii jl t ·1 i ! '. I 1 ii These observations reflect site conditions at the time of our investigation and do not preclude future changes in local groundwater conditions from excessive irrigation, precipitation, or other conditions that were not obvious at the time of our investigation. Based on the permeability contrasts between any proposed fill and the old paralic deposits, and the Santiago Formation, perched groundwater conditions may develop in the future due to excessive irrigation, poor drainage or damaged utilities, and should be anticipated. Should manifestations of this perched condition (i.e., seepage) develop in the future, this office could assess the conditions and provide mitigative recommendations, as necessary. The potential for perched water to occur after development should be disclosed to all interested/affected parties. MASS WASTING/LANDSLIDE SUSCEPTIBILITY Based on our review of landslide hazard mapping by Tan and Giffen (1995), the subject site is located within r~lative landslide susceptibility Subarea 2. This subarea contains sites that are marginally susceptible to landslides. However, no landslide debris has been mapped within the site (Kennedy and Tan; 2005 and 2007). In addition, GSI did not observe geomorphic expressions indicative of deep-seated landslides during our site reconnaissance and exploration. Further, landslide debris and geologic structures attributed to landsliding were not encountered during our field investigation. The onsite earth materials are considered erosive. Thus, prudent control of surface runoff water is recommended. FAULTING AND REGIONAL SEISMICITY Local and Regional Faults Our review of Kennedy and Tan (2005 and 2007), and Jennings and Bryant (2010) indicates that there are no known faults crossing this site, and the site is not within an Alquist-Priolo Earthquake Fault Zone (Bryant and Hart, 2007). However, the site is situated in a region subject to strong earthquakes occurring along active faults. These faults include, but are not limited to: the San Andreas fault; the San Jacinto fault; the Elsinore fault; the Coronado Bank fault zone; and the Newport-Inglewood -Rose Canyon fault zone (NIRCFZ). The location of these, and other major faults relative to the site, are indicated on the California Fault Map in Appendix C. According to Blake (2000a), the closest known active fault to the site is the offshore segment of the Newport-Inglewood fault, which is located at a distance of approximately 4.8 miles [mi] (7 .8 kilometers [km]) from the approximate centroid of the site. Portions of this fault have demonstrated movement in the Holocene Epoch (i.e., last 11,000 years) and therefore, and portions are located in an Alquist-Priolo Earthquake Fault Zone (Bryant and Hart, 2007). Cao, et al. (2003) indicate that offshore segment of the Newport-Inglewood Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W .0. 6935-A-SC November 3, 2015 Page 6 I I I I I I ,I I I I I I fault is a "B" fault (i.e., the slip rate is less than 5 millimeters per year) and is capable of producing a maximum magnitude (Mw) 7 .1 earthquake. 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 affect on the site, should they experience activity, are listed in Appendix C (modified from Blake, 2000a). Seismicity Deterministic Maximum Credible Site Acceleration The acceleration-attenuation relation of Bozorgnia, Campbell, and Niazi (1999) has been incorporated into EQFAUL T (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) was computed by one user-selected acceleration-attenuation relation that is contained in EQFAULT. Based on the EQFAULT program, a peak horizontal ground acceleration from an upper bound event at these sites may be on the order of 0.61 g. The computer printouts of pertinent portions of the EQFAUL T program are included within Appendix C. Historical Site Acceleration Historical site seismicity was evaluated with the acceleration-attenuation relation of Bozorgnia, Campbell, and Niazi (1999), and the computer program EQSEARCH (Blake, 2000b, updated to January 2015). 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 1800 through January 2015. Based on the selected acceleration-attenuation relationship, a peak horizontal ground acceleration is estimated, which may have effected the sites 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 January 2015 was 0.23 g. Historic earthquake epicenter maps and seismic recurrence curves are also estimated/generated from the historical data. Computer printouts of the EQSEARCH program are presented in Appendix C. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W .0. 6935-A-SC November 3, 2015 Page 7 J I ;3 II I ,., J I . I I I ·--·--······----------------------- Seismic Shaking Parameters Based on the site conditions, the following table summarizes the updated site-specific design criteria obtained from the 2013 CBC (CBSC, 2013), Chapter 16 Structural Design, Section 1613, Earthquake Loads. The computer program "U.S. Seismic Design Maps," provided by the United States Geologic Survey (USGS, 2013) was utilized for design (http://geohazards.usgs.gov/designmaps/us/application.php). The short spectral response utilizes a period of 0.2 seconds. •; . • .. t·;,.I'.f\'\•. ... 2013CBC,S~$M1CfDES1GNP,A~AfAETEf1S• •·•·"•"",. "\':.•fa.\.YL /,, i ..... ···•··. 1.~;·PARAMETEfl .. ?',i;n.> 1 VALU£\· it ioiaCsc·ANl)/Oi/ti~siENC~· Site Class Spectral Response -(0.2 sec), S5 Spectral Response -(1 sec), S1 Site Coefficient, Fa Site Coefficient, F v Maximum Considered Earthquake Spectral Response Acceleration (0.2 sec), SMs Maximum Considered Earthquake Spectral Response Acceleration (1 sec), SM1 5% Damped Design Spectral Response Acceleration (0.2 sec), S05 5% Damped Design Spectral Response Acceleration (1 sec), S01 Seismic Design Category C 1.158 g 0.444 g 1.000 1.356 1.158 g 0.602 g 0.772 g 0.401 g 0.460 g D Section 1613.3.2/ASCE 7-10 (Chapter 20) Figure 1613.3.1 (1) Figure 1613.3.1 (2) Table 1613.3.3(1) Table1613.3.3(2) Section 1613.3.3 (Eqn 16-37) Section 1613.3.3 (Eqn 16-38) Section 1613.3.4 (Eqn 16-39) Section 1613.3.4 (Eqn 16-40) ASCE 7-10 (Eqn 11.8.1) Section 1613.3.5/ASCE 7-10 (Table 11.6-1 or 11.6-2) I ' ·· GENERAL SEISMIC PARAMETERS.· . ··· 1 Distance to Seismic Source (Newport-Inglewood [Offshore]) 4.9 mi (7.9 km)<'l Upper Bound Earthquake (Newport-Inglewood [Offshore]) Mw = 7.1<2l c,, -From Blake (2000a) <2l -Cao, et al. (2003) Conformance to the criteria above for seismic design does not constitute any kind of guarantee or assurance that significant structural damage or ground failure will not occur in the event of a large earthquake. The primary goal of seismic design is to protect life, not Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 8 J J D I I I ;I ij j I jl 11 i ;D I lD I I I 11 to eliminate all damage, since such design may be economically prohibitive. Cumulative effects of seismic events are not addressed in the 2013 CBC (CBSC, 2013) and regular maintenance and repair following locally significant seismic events (i.e., Mw5.5) will likely be necessary. It is important to keep in perspective that in the event of an upper bound or maximum credible earthquake occurring on any of the nearby major faults, strong ground shaking would occur in the subject site's general area. Potential damage to any structure(s) would likely be greatest from the vibrations and impelling force caused by the inertia of a structure's mass than from those induced by the hazards considered above. Following implementation of remedial earthwork and design of foundations described herein, this potential would be no greater than that for other existing structures and improvements in the immediate vicinity that comply with current and adopted building standards. LIQUEFACTION POTENTIAL Liquefaction Liquefaction describes a phenomenon in which cyclic stresses, produced by earthquake-induced ground motion, create excess pore pressures in relatively cohesion less soils. These soils may thereby acquire a high degree of mobility, which can lead to vertical deformation, lateral movement, lurching, sliding, and as a result of seismic loading, volumetric strain and manifestation in surface settlement of loose sediments, sand boils and other damaging lateral deformations. This phenomenon occurs only below the water table, but after liquefaction has developed, it can propagate upward into overlying non-saturated soil as excess pore water dissipates. One of the primary factors controlling the potential for liquefaction is depth to groundwater. Typically, liquefaction has a relatively low potential at depths greater than 50 feet and is unlikely and/or will produce vertical strains well below 1 percent for depths below 60 feet when relative densities are 40 to 60 percent and effective overburden pressures are two or more atmospheres (i.e., 4,232 psf [Seed, 2005]). The condition of liquefaction has two principal effects. One is the consolidation of loose sediments with resultant settlement of the ground surface. The other effect is lateral sliding. Significant permanent lateral movement generally occurs only when there is significant differential loading, such as fill or natural ground slopes within susceptible materials. This condition does not exist at the site. Liquefaction susceptibility is related to numerous factors and the following five conditions should be concurrently present for liquefaction to occur: 1) sediments must be relatively young in age and not have developed a large amount of cementation; 2) sediments must generally consist of medium-to fine-grained, relatively cohesionless sands; 3) the sediments must have low relative density; 4) free groundwater must be present in the Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 9 "'I J J 11 I 11 I• ·.11 ~ ii '· I I D I I I I I sediment; and 5) the site must experience a seismic event of a sufficient duration and magnitude, to induce straining of soil particles. Only about one to perhaps two of these concurrently necessary conditions have the potential to affect the sites in their current state. Therefore, this site is considered at low risk for seismically induced liquefaction. Seismic Densification Seismic densification is a phenomenon that typically occurs in low relative density granular soils (i.e., United States Soil Classification System [USCS] soil types SP, SW, SM, and SC) that are above the groundwater table. These unsaturated granular soils are susceptible if left in the original density (unmitigated), and are generally dry of the optimum moisture content (as defined by the ASTM D 1557). During seismic-induced ground shaking, these natural or artificial soils deform under loading and volumetrically strain, potentially resulting in ground surface settlements. The recommended remedial earthwork, discussed herein, would reduce the potential for seismic densification. However, some densification may occur on the adjoining un-mitigated properties or areas of the subject site where remedial grading is not performed. Some of the dry (i.e., well below optimum moisture content) old paralic deposits, consisting of uses soil types SP or SM, above the perched groundwater table may exhibit low magnitude densification. This may influence improvements located above a 1 :1 (horizontal:vertical [h:v]) projection up from the perimeter of the site or the limits of remedial grading. Special setbacks and/or foundations would be recommended for settlement-sensitive improvements within the influence of densifiable soils. Our evaluation assumes that the current offsite conditions will not be significantly modified by future grading at the time of the design earthquake, which is a reasonably conservative assumption. Summary It is the opinion of GSI that the susceptibility of the developed sites to experience damaging deformations from seismically-induced liquefaction and densification is relatively low owing to the recommended recompaction of low density soils (as discussed herein) and the dense nature of the formational earth units that directly underlie the site to depth. Densification occurring on unmitigated, adjoining properties or portions of the subject site where remedial grading is not performed could potentially affect the proposed improvements located above a 1 : 1 (h :v) projection up from the perimeter of the site or the limits of remedial grading. Special setbacks for perimeter improvements may be necessary to mitigate densification. This would be best evaluated during the grading plan review stage. Other Geologic/Secondary Seismic Hazards The following list includes other geologic/seismic 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: Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 10 • • • • • Dynamic Settlement Surface Fault Rupture Ground Lurching or Shallow Ground Rupture Tsunami Seiche SUBSIDENCE The effects of areal subsidence generally occur at the transition or boundaries between low-lying areas and adjacent hillside terrain, where materials of substantially different engineering properties (i.e., alluvium vs. bedrock) are present, or in areas of overdraft owing to groundwater, oil, or gas withdrawal. It is our understanding that groundwater withdrawal is currently occurring in the site vicinity. However, our review of available in- house documents indicate there have been no documented incidents of subsid~ in the City of Carlsbad. In light of the above and the relatively dense nature of the underlying sedimentary deposits, the potential for this phenomena to affect the site is considered low. SLOPE STABILITY Based on site conditions and planned improvements, significant permanent cut and/or fill slopes are not anticipated. Therefore, no recommendations are deemed necessary. Temporary slopes for construction (i.e., trenching, etc.) are discussed in subsequent sections of our report. EXCAVATION CHARACTERISTICS Based on our experience with similar nearby sites, we anticipate that site soils can be excavated using standard earth-moving equipment with littte tb moderate difficulty. However, localized cemented zones within the old paralic deposits, while not encountered, but known to occur in the area, may require the use of heavy ripping and/or rock breaking equipment (i.e., hoe ram). Excavation within the Santiago Formation, may present moderate difficulty during excavation. Site earth materials are generally anticipated to reduce to particles sizes of 12 inches or less during excavation. LABORATORY TESTING Laboratory tests were performed on relatively undisturbed and representative bulk samples of site earth materials collected during our subsurface exploration in order to evaluate their physical characteristics. Test procedures used and results obtained are presented below. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoUs, Inc. W.O. 6935-A-SC November 3, 2015 Page 11 ''" I I I I Classification Soils were visually classified with respect to the Unified Soil Classification System (U.S.C.S.) in general accordance with ASTM D 2487 and D 2488. The soil classifications of the onsite soils are provided on the Boring Logs in Appendix B. Laboratory Standard The laboratory standard maximum dry density and optimum moisture content was evaluated for a representative sample of near surface soil in general accordance with ASTM D 1557. A maximum dry density of 124.0 pcf, at an optimum moisture content of 12.5 percent, was evaluated for a sample obtained from Boring 8-1, at a depth of about 1 % to 3 feet below grade. Expansion Index Tests were performed on a representative soil sample collected near the currently planned bearing elevation to evaluate expansion potential. Testing and expansion potential classification were performed in general accordance with ASTM D 4829. The results of the expansion index test are provided in the following table: B-1 @1%to3 73 Medium B-2@6% 3 Very Low * 0-20 = verv low, 21-50 = low, 51-90 = medium, 91-130 = hiAh, >130 verv hiAh Atterberg Limits Testing was performed on a representative soil sample, collected near the currently planned bearing elevation (Boring B-1 at approximately 8% feet depth), in order to evaluate the liquid limit, plastic limit, and plasticity index (P.I.) in general accordance with ASTM D 4318. The test results are summarized in the following table and in Appendix D. B-1 @1%-3 Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef 41 15 GeoSoils, Inc. 26 (CL) W.O. 6935-A-SC November 3, 2015 Page 12 , • .1 t :1 t 11 I 1• jl I I I I I :1 I JI Direct Shear Test Shear testing was performed on relatively undisturbed samples of site soil in general accordance with ASTM test method D 3080 in a Direct Shear Machine of the strain control type. The shear test results are presented as follows: ··'·LOcATtq~),~;'1,0/.•~ .. = .. ======== DE~ {f6£1)'(i:,./ .. :COME ,,;:t -~·t-.. ::'t'z-,'%/-Ji,\~< f~fc;i<";: B-1@ 1% -3 239 25 234 25 B-1 @ 10 98 41 22 35 Consolidation Test A consolidation test was performed on a selected undisturbed sample collected from Boring B-2 at a depth of 5 feet below the existing grade. Testing was performed in general accordance with ASTM Test Method D 2435. Test results are presented as in Appendix D. The testing indicates that the sample exhibited approximately 0.4 percent of compression when subjected to loads between150 psf and 1,000 psf, prior to inundation. Following inundation at 1,000 psf, the sample underwent approximately 0.4 percent of hydrocollapse and then exhibited approximately 1 .2 percent compression under increasing loads up to and including 10,000 psf. Saturated Resistivity, pH, and Soluble Sulfates, and Chlorides GSI conducted sampling of onsite earth materials for general soil corrosivity and soluble sulfates, and chlorides testing. The testing included evaluation of soil pH, soluble sulfates, chlorides, and saturated resistivity. Test results are presented in Appendix D and the following table: ~;;,.~J~~;~1ii>~t ·•· ... Aftt)C[)Ef'.TH:~(Ff); B-1 @ 1 %-3 8-2@ 15 Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef 8.10 8.13 ; SATU~AJED;~· ,;t 9ESIST4V1'f'( otim-cmt.·••· 620 1,500 GeoSolls, Inc. .... ~t~i~lt: !, Jt SOLUBLE> > .• suu=ATEs.¥ •• t:cttt:o.a1oes '!' ':']'' •'''mj~I1's<' I;~,,/ . ···•·mJ:; 0.14'10 0.0360 10 15 W.O. 6935-A-SC November 3, 2015 Page 13 I~ '" LI a C I I I I Corrosion Summary The laboratory tests indicate that the tested samples of the onsite soils are moderately alkaline with respect to soil acidity/alkalinity; are corrosive to exposed, buried metals when saturated; present negligible, to moderate sulfate exposure to concrete; and have low chloride content. It should be noted that GSI does not consult in the field of corrosion engineering. Thus, the client, project architect, and project structural engineer should agree on the level of corrosion protection required for the project and seek consultation from a qualified corrosion consultant as warranted, especially in light of the site's proximity to the Pacific Ocean, which is a corrosive environment. It should be noted that sulfate levels indicate a sulfate exposure Class S1, and a moderate corrosion exposure class of C1 (concrete will be exposed to moisture), per Table 4.3.1 of ACI 318-11 (ACI, 2011). PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS Based on our field exploration, laboratory testing, and geotechnical engineering analysis, it is our opinion that the subject site is suitable to receive the proposed development from a geotechnical engineering and geologic viewpoint, provided that the recommendations presented in the following sections are incorporated into the design and construction phases of site development. The primary geotechnical concerns with respect to the proposed development and improvements are: • Earth materials characteristics and depth to competent bearing material below existing grades. • Planned excavations in close proximity to property lines, and adjacent structures. • Perched groundwater and its potential affects during construction and following development. A permanent sump pump may be necessary. • Temporary slope stability. • On-going expansion and corrosion potential of site soils. • Settlement potential. • Erosiveness of site earth materials. • 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 unless the changes are reviewed and the recommendations of this report verified or modified in writing by this office. Foundation design parameters are considered preliminary until the foundation design, layout, and structural loads are provided to this office for review. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 14 di 1. 2. 3. 4. 5. Soil engineering, observation, and testing services should be provided during grading to aid the contractor in removing unsuitable soils and in his effort to compact the fill. Geologic observations should be performed during grading and foundation construction to confirm and/or further evaluate the geologic conditions reported herein. Although unlikely, if adverse geologic structures/conditions are encountered, supplemental recommendations and earthwork may be warranted. Surficial colluvium, undocumented fill, and any weathered old paralic deposits (if present) are considered unsuitable for the support of the planned settlement-sensitive improvements (i.e., foundations, concrete slab-on-grade floors, pavements, hardscape, etc.) or new planned fills (if any). Unsuitable soils within the influence of planned settlement-sensitive improvements and/or planned fill should be removed to expose suitable old paralic deposits and then be reused as properly engineered fill. Based on the available data, suitable dense, unweathered old paralic deposits occur at approximate depths of 2 to 4 feet below the existing grades. Thus, remedial grading excavations should to extend to this depth. Based on our understanding of the currently planned development, unsuitable earth materials should be removed by default during planned excavations for the basement, however, the recommended removals will likely need to be performed for the ground floor portions of the structure, and ancillary improvements. Thus, consideration should be given to remediating the surficial soils prior to plan excavation in areas that will remain at or near existing grade. Expansion index (E.1.) testing, performed on a representative soil sample collected near the planned pad grade elevation, indicates expansion indices ranging from very low (E.I. less than 20), to medium (E.I. evaluated as 73). Thus, detrimentally expansive soils exist onsite. Atterberg Limits testing, performed on a representative soil sample collected near the planned pad grade elevation, indicates plastic soil conditions within the old paralic deposits, as such. It should be recognized that some medium expansive soil (E.I. = 50 to 90) with a plasticity index (P.I.) greater than 15 are present onsite and should be considered in design, per the 2013 CBC. Corrosion testing, performed on representative soil samples collected near the planned pad grade elevation, indicates that the soils are mildly alkaline with respect to soil acidity /alkalinity; are corrosive to severely corrosive to exposed buried metals when saturated; present negligible to moderate sulfate exposure to concrete; and contain low concentrations of soluble chlorides. It should be noted that GSI does not consult in the field of corrosion engineering. Thus, the client, project architect, and project structural engineer should agree on the level of corrosion protection required for the project and seek consultation from a qualified corrosion consultant as warranted, especially in light of the site's proximity to the Pacific Ocean, which is a corrosive environment. Mr.Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 15 • ·-i .J m I l I ' j I I I 6 . 7. 8. A perched groundwater table was encountered along, and near the contact between old paralic deposits and the underlying Santiago Formation, at an approximate depths on the order of respective depths of 12 feet below the existing grades. Based on site surface elevations shown on MAA (2015) the elevation of the perched water table is estimated at approximately 27 to 30 feet MSL. This water table is likely the result of infiltrated, up-gradient runoff and irrigation waters collecting near the geologic contact between the more permeable old paralic deposits and the underlying, less permeable Santiago Formation. This perched groundwater table is not anticipated to significantly constrain the proposed development, provided it is planned for. However, any planned excavation extending near the elevations noted above may encounter caving soils, seepage, and/or saturated soils. The need for some dewatering efforts during construction should be considered while planning. A permanent sump pump may be necessary. The currently planned development includes planned excavations up to approximately 12 to 14 feet, in close proximity to adjacent property and structures. Where planned excavations do not allow for the temporary slopes, recommended herein, a properly designed shoring system will be necessary. Recommendations for temporary and permanent shoring systems are provided herein. Site soils are considered erosive. Surface drainage should be designed to eliminate the potential for concentrated flows. Positive surface drainage away from foundations is recommended. Temporary erosion control measures should be implemented until vegetative covering is well established. The owner will need to maintain proper surface drainage over the life of the project. 9. On a preliminary basis, temporary slopes should be constructed in accordance with CAL-OSHA guidelines for Type "B" soils (i.e., 1 :1 [h:v] slope), provided groundwater and/or running sands is not present. Should such conditions be exposed, temporary slopes should be constructed in accordance with CAL-OSHA guidelines for Type "C" soils (i.e., 1 %:1 [h:v] slope). All temporary slopes should be evaluated by the geotechnical consultant, prior to worker entry. Although not anticipated at this time, exposed conditions may require inclining temporary slopes to flatter gradients. 10. The seismicity-acceleration values provided herein should be considered during the design and construction of the proposed development. 11 . General Earthwork and Grading Guidelines are provided at the end of this report as Appendix E. Specific recommendations are provided below. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935agef CeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 16 :J ' :J lJ I iJ i I ,, I I I "" l JJ I ,, ;1 'O ~ l J I I I EARTHWORK CONSTRUCTION RECOMMENDATIONS General All earthwork should conform to the guidelines presented in Appendix Chapter "J" of the 2013 CBC (CBSC, 2013), the requirements of the City of Carlsbad, and the General Earthwork and Grading Guidelines presented in Appendix E, except where specifically superceded in the text of this report. Prior to earthwork, a GSI representative should be present at the preconstruction meeting to provide additional earthwork guidelines, if needed, and review the earthwork schedule. This office should be notified in advance of any fill placement, supplemental regrading of the site, or backfilling underground utility trenches and retaining walls after rough earthwork has been completed. This includes grading for pavements and hardscape. During 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 Health Act (OSHA), and the Construction Safety Act should be met. It is the onsite general contractor and individual subcontractors responsibility to provide a save working environment for our field staff who are onsite. GSI does not consult in the area of safety engineering. Construction Phasing In order to facilitate adequate construction of the near surface fill cap, it is recommended that overexcavation of the near surface fills and old paralic deposits is completed prior to excavation for the basement level. Preliminary Earthwork Factors (Shrinkage/Bulking) The volume change of excavated materials upon compaction as engineered fill is anticipated to vary with material type and location. The overall earthwork shrinkage and bulking may be approximated by using the following parameters: Quaternary Colluvium/Undocumented Fill . . . . . . . . . . . . . . . . . . 10% to 15% shrinkage Quaternary Old Paralic Deposits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0% to 5% bulking Santiago Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3% to 8% bulking It should be noted that the above factors are estimates only, based on preliminary data. Colluvium/disturbed natural ground may achieve higher shrinkage if organics or clay content is higher than anticipated. Further, bulking estimates for old paralic deposits may be less than indicated above depending on the degree of weathering. Final earthwork balance factors could vary. In this regard, it is recommended that balance areas be Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 17 ., J il 1 11 l II!! I I ' "' iii - reserved where grades could be adjusted up or down near the completion of grading in order to accommodate any yardage imbalance for the project. If the Client requires additional information regarding embankmentfactors, additional studies could be provided upon request. Demolition/Grubbing 1 . 2. 3. 4. 5. Vegetation and any miscellaneous debris should be removed from the areas of proposed grading. Any existing subsurface structures uncovered during the recommended remedial earthwork should be observed by GSI so that appropriate remedial recommendations can be provided. 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 a 2-to 3-sack sand-cement slurry or fill materials that have been moisture conditioned to at least optimum moisture content and compacted to at least 95 percent of the laboratory standard (ASTM D 1557). Onsite septic systems (if encountered) should be removed in accordance with San Diego County Department of Environmental Health (DEH) standards/guidelines. Existing, abandoned wells should be destroyed in accordance with DEH standards/guidelines. Treatment of Existing Ground/Remedial Grading 1. 2. Remedial grading should consist of all surficial colluvium, undocumented fill, and any weathered old paralic deposits (if present) to encounter the suitable, dense unweathered old paralic deposits, or Santiago Formation. Based on the available subsurface data, the depth of remedial grading excavations are anticipated to be on the order of 2 to 4 feet below the existing grades. Based on our understanding of the currently planned development, the removal of unsuitable soils is anticipated to generally be completed by default during the planned excavations for the basement area. If necessary, these removed soils may be re-used in engineered fills, provided that the soil is cleaned of any deleterious material and moisture conditioned, and compacted to a minimum 95 percent relative compaction (ASTM D 1557). Remedial grading should be completed throughout the entire property. Remedial grading may utilize alternating ("A', "B", and "C") slot excavations adjacent to any settlement sensitive improvements (walls, building, etc.) to remain about the perimeter of the site. A maximum slot cut width of 8 feet may be considered, on a preliminary basis. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 18 ,., J J J I I ,I 1; 3. 4. 5. Subsequent to the above, remedial excavations, should be scarified to a depth of at least 8 inches, brought to at least optimum moisture content, and recompacted to a minimum relative compaction of 95 percent of the laboratory standard (ASTM D 1557), prior to any fill placement. Localized deeper remedial grading excavations may be necessary due to buried drainage channel meanders or dry porous materials, septic systems, etc. The project geotechnical consultant should observe all remedial grading excavations during earthwork construction. If deeper removals are needed, below the designed height of the adjacent shoring, a slot cut approach may be used to reduce the potential for excessive shoring deflection. Soils exposed at the basement floor-level subgrade elevation and the bottom of remedial grading excavations should be evaluated by a GSI representative, prior to any scarification or fill placement. Overexcavation In order to provide for the uniform support of the structure, and reduce the potential for damaging differential settlement, GSI recommends that the ground floor portions of the structure (i.e., the east and west of the garage basement) are undercut to provide at least 2 feet of compacted fill beneath the foundation system above the basement. Based on a 24-to 30-inch deep footing, the depth of undercut should be on the order of 4 to 4% feet below existing grades. Following overexcavation, the exposed subsoils should be scarified at least 12 inches, moisture conditioned to at least optimum moisture content and then be recompacted to at least 95 percent of the laboratory standard (ASTM D 1557). The overexcavation may then be backfilled with the excavated earth materials that have been placed in relatively thin (i.e., approximately 8-to 10-inch thick) lifts, moisture conditioned to at least optimum moisture content, and compacted to at least 95 percent of the laboratory standard (ASTM D 1557) with vibratory compaction equipment. Grade transitions between differing building floor elevations may be accommodated by the construction of 2: 1 (h :v) or flatter slopes. The configuration of the overexcavation should be re-evaluated once grading and foundation plans have been provided for GSI review. Cross sections may be developed at that time to assist the contractor in grading and shoring costs/value engineering. Fill Placement Subsequent to ground preparation, any required fill materials should be brought to at least optimum moisture content, placed in thin 6-to 8-inch lifts, and mechanically compacted to obtain a minimum relative compaction of 95 percent of the laboratory standard (ASTM D 1557). Fill materials should not be greater than 12 inches in any dimension. Underground-utility agencies/companies may have stricter requirements with respect to the particles sizes of backfill placed in utility trenches. Mr.Michael Donovan 2646 State Street, Carlsbad File :e :\wp 12\6900\6935agef GeoSolls, Inc. W.O. 6935-A-SC November 3, 2015 Page 19 J J jl I :1 im ,. ID , .. I ,1 •• J J Subdrains Given the relatively flat lying conditions across the site, a gravity flow system at street level may be provided by finished grading design. In the below grade basement/parking area(s), the wall subdrains will need to have their flow collected, tight-lined, and utilize a sump pump, to direct the water to the street. Walls below grade will need to be "waterproofed." Temporary Slopes Unsupported temporary excavation walls ranging between 4 and 20 feet in gross overall height may be constructed in accordance with CAL-OSHA guidelines for Type "B" soils (i.e., 1 :1 [h:v] slope), provided that groundwater and/or running sands are not exposed. Should such conditions be exposed, temporary slopes should be constructed in accordance with CAL-OSHA guidelines for Type "C" soils (i.e., 1 %:1 [h:v] slope) All temporary slopes should be observed by a licensed engineering geologist and/or geotechnical engineer, prior to worker entry into the excavation. Based on the exposed field conditions, inclining temporary slopes to flatter gradients or the use of shoring may be necessary if adverse conditions are observed. If temporary slopes conflict with property boundaries or other boundary restrictions, shoring or alternating slot excavations may be necessary. The need for shoring or alternating slot excavations could be further evaluated during grading plan review stage. Soil and building materials and heavy construction equipment should not be stockpiled, stored, nor operated within "H" feet from the top of temporary excavations walls where "H" equals the height of the excavation wall. Import Fill Materials All import fill material should be tested by GSI prior to placement within the site. GSI would also request environmental documentation (e.g., Phase I Environmental Site Assessment) pertaining to proposed export site, to evaluate if the proposed import could present an environmental risk to the planned development. At least five (5) business days of lead time will be necessary for the required laboratory testing and document review. PRELIMINARY RECOMMENDATIONS -FOUNDATIONS General Preliminary recommendations for foundation design and construction are provided in the following sections. These preliminary recommendations have been developed from our understanding of the currently planned site development, site observations, subsurface exploration, laboratory testing, and engineering analyses. Foundation design should be re-evaluated at the conclusion of site grading/remedial earthwork for the as-graded soil conditions. Although not anticipated, revisions to these recommendations may be necessary. In the event that the information concerning the proposed development plan Mr. Michael Donovan 2646 State Street, Carlsbad File :e:\wp 12\6900\6935a.gef GeoSolls, Inc. W.O. 6935-A-SC November 3, 2015 Page 20 I - J J I I ii l ·1 D I I I I I I is not correct, or any changes in the design, location or loading conditions of the proposed additions are made, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and conclusions of this report are modified or approved in writing by this office. The information and recommendations presented in this section are not meant to supercede design by the project structural engineer or civil engineer specializing in structural design. Upon request, GSI could provide additional input/consultation regarding soil parameters, as related to foundation design. GSI understands that the project is in its very conceptual stages. Thus, the foundation design recommendations, included herein, are based on anticipated average and maximum static column loads of 100 and 250 kips, respectively. Maximum wall loads are anticipated to be on the order of 5 kips per lineal foot. The basement/garage slabs are anticipated to have typical car and light loads on the order of 50 to 200 psf. It is unknown if equipment and elevator pit areas will be included in the design. GSI does not anticipate high vibratory equipment loads on the basement/garage floor slabs. GSI also does not anticipate highly sensitive electrical equipment mounted on the basement floor slab. The lower basement/parking finish grade is anticipated to be at a elevation of about 25% to 27% feet MSL. Based on the above, we have considered the following design alternatives: • Isolated spread/continuous footings (i.e., conventional). • Mat foundation The foundation design recommendation contained in this report may be modified once actual loading conditions have been provided for GSI review. All foundations should be designed using at a minimum, the parameters and static settlements described herein. All foundations should be evaluated for seismic deformations described herein Expansive Soils Current laboratory testing indicates thatthe onsite soils exhibit expansion index(E.I.) values ranging on the order of less than 20 to 73 (very low to medium), with a plasticity index (P.I.) for medium expansive soils evaluated as 26. As such, some site soil meets the criteria of detrimentally expansive soils as defined in Section 1803.5.2 of the 2013 CBC. Foundation systems constructed within the influence of detrimentally expansive soils (i.e., E.I. > 20 and P .I. > 15) will require specific design to resist expansive soil effects per Sections 1808.6.1 or 1808.6.2 of the 2013 CBC, and should be reviewed by the project structural engineer. Preliminary Conventional Foundation Design The following foundation construction recommendations are presented as a minimum criteria from a soils engineering viewpoint, where the planned improvements are underlain Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 21 ~ J '3 ,I 1. 1• I I 11 I I I I I I I 'I by at least 7 feet of non-detrimentally expansive soils (i.e., E.l.<21 and P.I. <15). Should foundations be underlain by (detrimentally) expansive soils, as is anticipated for the ground floor portions of the structure, they will require specific design to mitigate expansive soil effects as required in Sections 1808.6.1 or 1808.6.2 of the 2013 CBC. 1. 2. Conventional foundation systems should be designed and constructed in accordance with guidelines presented in the 2013 CBC. Based on the anticipated foundation loads and preliminary design information provided us, it is our opinion that the proposed structure could be favorably supported on a minimum 2-foot thick layer of engineered fill, compacted to at least 95 percent of the laboratory standard (ASTM D 1557), overlying dense, unweathered old paralic deposits. Building loads may be supported on continuous or isolated spread footings designed in accordance with the following recommendations. 30 to 36 2.5 ksf 2.5 ksf 48 3.0 ksf 3.0 ksf The above values are for dead plus live loads and may be increased by one-third for short-term wind or seismic loads. Where column or wall spacings are less than twice the width of the footing, some reduction in bearing capacity may be necessary to compensate for the effects of footings with shared bearing soils. GSI should review the foundation plans and overlying building load patterns and evaluate this potential with the structural consultant. Reinforcement should be designed in accordance with local codes and structural considerations. The recommended allowable bearing capacity provided herein is generally based on maximum static total and differential settlements of up to 2 inches and 1 inch, respectively. Differential settlements are over a distance of 50 lateral feet or between heaviest and lightest foundation loads. Actual settlement can be estimated on the basis that settlement is roughly proportional to the net contact bearing pressure on compacted fill, or formation. The majority of the settlement should occur during construction as building loads are applied. Since settlement is a function of footing size and contact bearing pressure, some static differential settlement can be expected between adjacent columns or walls where a large differential loading condition exists. However, for most cases, differential settlements are considered unlikely to exceed 1 V4 inches in 50 feet (angular Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 22 J J ii ! 11 I I ID I j, D rn ~ fi 3 I I I 3. 4. 5. 6. 7. 8. 9. distortion = 1 /480). With increased footing depth/width ratios, differential settlement should be less. The anticipated total vertical deformation (post-earthquake) for the design seismic event may be on the order of ± 1 inch with a potential seismic differential settlement of approximately %-inch to %-inch over 50 feet horizontally (i.e., angular distortion approximately 1 /800) under the basement/garage structure. Other settlement-sensitive improvements (i.e., underground utilities, pavements, flatwork) are susceptible to seismic settlement outside the footprint of the basement/garage structure. These evaluations have assumed a local control of groundwater around the foundation. Foundation embedment depth excludes concrete slabs-on-grade, and/or slab underlayment. Foundations for the ground level structure should bear entirely on a minimum 2-foot thick layer of approved engineered fill overlying unweathered, dense old paralic deposits. Foundations for the basement level should bear entirely on sedimentary bedrock (Santiago Formation). All isolated pad footings should be tied to the perimeter foundation in at least one direction to reduce the potential for lateral drift. For foundations deriving passive resistance from engineered fill, prepared in accordance with the recommendations provided in this report, a pressure of 250 pcf may be used if the footing face is embedded entirely in engineered fill, and the embedment is 24 to 48 inches. For footings embedded entirely into dense, unweathered old paralic deposits or Santiago Formation, a passive resistance value of 300 pcf may be used. The upper 6 inches of passive pressure should be neglected if not confined by slabs or pavement. 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. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. Although not anticipated, given our understanding of the proposed development, all footing setbacks from slopes should comply with Figure 1808.7.1 of the 2013 CBC. GSI recommends a minimum horizontal setback distance of 7 feet as measured from the bottom, outboard edge of the footing to the slope face. Foundations should also extend below a 1 :1 (h:v) projection up from the bottom outside edge of remedial grading excavations. Footings for structures adjacent to retaining/privacy walls should be deepened so as to extend below a 1 :1 projection from the heel of the wall. Alternatively, walls may be designed to accommodate structural loads from buildings or appurtenances as described in the "Retaining Wall" section of this report. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 23 J IJ !I I I D 1 ll 11 t II l ll I I I I I ··-·----··-,,·------------------------- 1 o. Footings constructed below a 1 :1 projection from adjacent property lines should be designed for any applicable surcharge. PRELIMINARY CONVENTIONAL FOUNDATION CONSTRUCTION RECOMMENDATIONS Current laboratory testing indicates that some onsite soils meet the criteria of detrimentally expansive soils as defined in Section 1803.5.2 of the 2013 CBC. The following foundation construction recommendations are presented as a minimum criteria from a soils engineering viewpoint, where the planned improvements are underlain by at least 7 feet, and perhaps more (as determined during grading), of non-detrimentally expansive soils (i.e., E.l.<21 and P.I. <15). Should foundations be underlain by expansive soils, such as is anticipated for the ground floor portions of the structure, they will require specific design to mitigate expansive soil effects as required in Sections 1808.6.1 or 1808.6.2 of the 2013 CBC. 1. 2. 3. 4. Exterior and interior footings should be founded into approved engineered fill overlying dense unweathered old paralic deposits, or Santiago Formation bedrock, as indicated in the previous "Preliminary Foundation Design" section of this report. Reinforcement should be designed in accordance with local codes and structural considerations. All interior and exterior column footings, and perimeter wall footings, should be tied together via grade beams in at least one direction. The grade beam should be at least 24 inches square in cross section, and the base of the reinforced grade beam should be at the same elevation as the adjoining footings. · Reinforcement should be designed in accordance with local codes and structural considerations. A grade beam, reinforced as previously recommended and at least 24 inches square, should be provided across large (garage) entrances. The base of the reinforced grade beam should be at the same elevation as the adjoining footings. Non-vehicular slab-on-grade floors should have a minimum thickness of 5 inches with steel reinforcement consisting of No. 3 reinforcing bars positioned at 18 inches on center in two perpendicular directions (i.e., long axis and short axis). All slab reinforcement should be supported to ensure proper mid-slab height positioning during placement of the concrete. "Hooking" of reinforcement is not an acceptable method of positioning. Slab-on-grade floors intended to receive vehicular traffic should conform to the recommendations contained in the "Preliminary Recommendations for Portland Cement Concrete Pavements" section of this report. The actual thickness and steel reinforcement for concrete slab-on-grade floors should be determined by the project structural engineer, based on the anticipated loading conditions and building use. However, the slab thickness and steel reinforcement recommendations, contained herein, are considered minimum guidelines. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 24 I - ll I I 5. ··-·-~---------------------------- Slab subgrade pre-soaking may be required for the onsite soil conditions, should medium expansive soils be present near finish grade. If this is the case, the subgrade soils should be moisture conditioned to 2 percent over optimum moisture content (or 1.2 x optimum moisture, whichever is greater). This will need to be verified within 2 hours of the placement of underlayment sand and gravel and the vapor retarder. However, for very low to low expansive soils, the developer should consider moisture conditioning slab subgrade materials to at least optimum moisture content to a minimum depth of 12 inches, within 72 hours of the placement of underlayment sand and gravel and the vapor retarder. 6. Soils generated from footing excavations to be used onsite should be compacted to a minimum relative compaction of 95 percent of the laboratory standard (ASTM D 1557), whether the soils are to be placed inside the foundation perimeter or in other areas of the site. This material must not alter positive drainage patterns that direct drainage away from the structural areas and toward the street. 7. Reinforced concrete mix design should conform to recommendations contained in the "Soil Moisture Transmission Considerations" section of this report, and should consider the site's proximity to the Pacific Ocean corrosive environment, and the elevated chloride concentrations found in some of the onsite soils. Preliminary Mat Foundation Recommendations Given the nature of the proposed building (i.e., podium design), estimated column loads, the settlement potential of the underlying soils, and the proximity of a perched groundwater table below planned grades, a mat-type foundation system should be considered in providing foundation support for the proposed building in lieu of interconnected spread footings and grade beams with an overlying slab-on-grade floor. A mat foundation may consist of either reinforced uniform thickness foundation (UTF) slabs with turned down edges or may incorporate interconnected, interior stiffening beams. The latter is commonly referred to as a "waffle slab." The UTF approach is typically preferred by under-slab utility installers in order to reduce penetrations through the interior beams. UTF may be used in the mat design if the structural consultant can demonstrate that the alternative is equivalent to the recommended waffle slab/footings. The structural engineer may supersede the following recommendations based on the planned building loads and use. WAI (Wire Reinforcement Institute, 1996) methodologies for design may be used. Reinforcement bar sizing and spacing for mat slab foundations should be provided by the structural engineer. The parameters herein may require modification to mitigate the effects of the estimated total and differential settlements reported herein. Mat Foundation Design The design of mat foundations should incorporate the vertical modulus of subgrade reaction (l<s). This value is a unit value for a 1-foot square footing and should be reduced Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoUs, Inc. W.O. 6935-A-SC November 3, 2015 Page 25 D D (J ~ m I I I in accordance with the following equation when used with the design of larger foundations. This is assumes that the bearing soils will consist of a minimum 2-foot thick layer of engineered fill, compacted to at least 95 percent of the laboratory standard (ASTM D 1557), overlying dense, non-saturated unweathered old paralic deposits. where: Ks = unit subgrade modulus ~ = reduced subgrade modulus B = minimum or smallest foundation width of the mat (in feet) Mat Foundation Vertical Bearing For a mat foundation bearing uniformly on a minimum 2-foot thick layer of engineered fill, compacted to at least 95 percent of the laboratory standard (ASTM D 1557), overlying dense, non-saturated unweathered old paralic deposits, a maximum allowable vertical net bearing capacity of 2,000 psf is recommended. GSI anticipates that the bearing will very vary from 1,500 to 2,000 psf under higher concentrated loads across the mat. This value may be increased by one-third for short-term loads including wind or seismic and include a factor-of-safety of 3.0 for bearing capacity. The structural mat foundation slab should have a double mat of steel (minimum No. 5 reinforcing bars located at 12 inches on center each way, top and bottom). The thickness of the mat foundation slab should be defined by the structural consultant but not be less than 8 inches thick. Non-UTF mat foundations should incorporate an edge footing that is at least 18 inches wide and minimally extends 30 inches below the lowest adjacent grade into approved engineered fill. UTF mat embedment should be at least 24 inches below the lowest adjacent grade into approved engineered fill. Concrete mix design and slab underlayment recommendations are provided in the "Soil Moisture Transmission Considerations" section of this report. Mats may be designed by ACI 318-11 and/or WRI (1996). The need and arrangement of grade beams will be in accordance with the structural consultant's recommendations;. Mat Foundation Lateral Resistance Please refer to the "Preliminary Conventional Foundation Design" section of this report for recommendations pertaining to passive resistance and the coefficient offriction to be used in mat foundation design. Subgrade Modulus and Effective Plasticity The modulus of subgrade reaction (K5) and effective plasticity index (P .I.) to be used in mat foundation design (ACI 318-11 or WAI [19961) for the very low to medium expansive nature of the onsite soils are presented in the following table. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 26 lJ 1 jl 1• I I 1 • I D I: I 'I I I I I I ¥£RY t..C>VI 'f'9 t..C>W ~Xfl4NS10N; · '' .~: ' e1 = o~so r · ·· · K =100 Ci/inch, Pl <15 iMEOIUIIIE>tPANS101!1,,,<} ,,; ·· · · 1fa.';... s1-io·:r ;i , · K = 85 ci/inch Pl = 26 Other Structural Considerations for Mat-Type Foundations In order to mitigate the effects from post-development perched water and to impede water vapor transmission, structural mats, shall be in accordance with Table 4.2.1 of the ACI (2011) per the 2013 CBC (CBSC, 2013), for low permeability concrete (i.e., a maximum water-cement ratio of 0.50). Recommendations for slab underlayment and soil moisture transmission considerations are presented in a later section of this report. Nuisance cracking may be lessened by the addition of engineered reinforcing fibers in the concrete and careful control of water/cement ratios. The use of epoxy-coated reinforcing bars should be considered and are dependent on the structural consultant's waterproofing and corrosion specialists' recommendations. Corrosion and Concrete Mix Preliminary testing indicates that some site soils present a moderate sulfate exposure to concrete, per Table 4.2.1 of ACI 318-11 (ACI, 2011) and should be considered in the selection of concrete type for this project. Upon completion of grading, laboratory testing should be performed of site materials for corrosion to concrete and corrosion to steel. Additional comments may be obtained from a qualified corrosion engineer at that time. SOIL MOISTURE TRANSMISSION CONSIDERATIONS GSI has evaluated the potential for vapor or water transmission through the concrete floor slabs, in light of typical floor coverings, improvements, and use. Please note that slab moisture emission rates range from about 2 to 27 lbs/24 hours/1,000 square feet from a typical slab (Kanare, 2005), while floor covering manufacturers generally recommend about 3 lbs/24 hours as an upper limit. The recommendations in this section are not intended to preclude the transmission of water or vapor through the foundation or slabs. Foundation systems and slabs shall not allow water or water vapor to enter into the structure so as to cause damage to another building component or to limit the installation of the type of flooring materials typically used for the particular application (State of California, 2015). These recommendations may be exceeded or supplemented by a water "proofing" specialist, project architect, or structural consultant. Thus, the client will need to evaluate the following in light of a cost vs. benefit analysis (owner expectations and repairs/replacement), along with disclosure to all interested/affected parties. It should also be noted that vapor transmission will occur in new slab-on-grade floors as a result of chemical reactions taking place within the curing concrete. Vapor transmission through concrete floor slabs as a result of concrete curing has the potential to adversely affect sensitive floor coverings depending on the thickness of the concrete floor slab and the Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 27 J 'u ,, 1· :: I 1. lD D ll I I duration of time between the placement of concrete, and the floor covering. It is possible that a slab moisture sealant may be needed prior to the placement of sensitive floor coverings if a thick slab-on-grade floor is used and the time frame between concrete and floor covering placement is relatively short. Considering the E.I. test results presented herein, and known soil conditions in the region, the anticipated typical water vapor transmission rates, floor coverings, and improvements (to be chosen by the Client and/or project architect) that can tolerate vapor transmission rates without significant distress, the following alternatives are provided: • • • • Non-vehicular concrete slab-on-grade floors should be a minimum of 5 inches thick . Concrete slab underlayment should consist of a 15-mil vapor retarder, or equivalent, with all laps sealed per the 2013 CBC and the manufacturer's recommendation. The vapor retarder should comply with the ASTM E 17 45 -Class A criteria, and be installed in accordance with American Concrete Institute (ACI) 302.1 R-04 and ASTM E 1643. An example of a vapor retarder product that complies with ASTM E 17 45 - Class A criteria is Stego Industries, LLC's Stego Wrap. The 15-mil vapor retarder {ASTM E 17 45 -Class A) shall be installed per the recommendations of the manufacturer, including all penetrations (i.e., pipe, ducting, rebar, etc.). Concrete slabs, shall be underlain by 2 inches of clean, washed sand (SE > 30) above a 15-mil vapor retarder (ASTM E-17 45 -Class A, per Engineering Bulletin 119 [Kanare, 2005]) installed per the recommendations of the manufacturer, including all penetrations (i.e., pipe, ducting, rebar, etc.). The manufacturer shall provide instructions for lap sealing, including minimum width of lap, method of sealing, and either supply or specify suitable products for lap sealing (ASTM E 1745), and per code. ACI 302.1 R-04 (2004) states "If a cushion or sand layer is desired between the vapor retarder and the slab, care must be taken to protect the sand layer from taking on additional water from a source such as rain, curing, cutting, or cleaning. Wet cushion or sand layer has been directly linked in the past to significant lengthening of time required for a slab to reach an acceptable level of dryness for floor covering applications." Therefore, additional observation and/or testing will be necessary for the cushion or sand layer for moisture content, and relatively uniform thicknesses, prior to the placement of concrete. • The vapor retarder should be underlain by a capillary break consisting of at least 4 inches of clean crushed gravel with a maximum dimension of % inch (less than 5 percent passing the No. 200 sieve) placed directly on the prepared, moisture conditioned, subgrade. The vapor retarder should be sealed to provide a continuous retarder under the entire slab, as discussed above. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 28 J I: D la I I I IJ lJ [J Il II I I :J 'I 'I :1 .I • Concrete should have a maximum water/cement ratio of 0.50. This does not supercede Table 4.3.1 of Chapter 4 of the ACI (2011) for corrosion or other corrosive requirements. Additional concrete mix design recommendations should be provided by the structural consultant and/or waterproofing specialist. Concrete finishing and workablity should be addressed by the structural consultant and a waterproofing specialist. • Where slab water/cement ratios are as indicated herein, and/or admixtures used, the structural consultant should also make changes to the concrete in the grade beams and footings in kind, so that the concrete used in the foundation and slabs are designed and/or treated for more uniform moisture protection. • The owner(s) should be specifically advised which areas are suitable for tile flooring, vinyl flooring, or other types of water/vapor-sensitive flooring and which are not suitable. In all planned floor areas, flooring shall be installed per the manufactures recommendations. • Equipment in garage or elevator pit areas may require special consideration depending on the sensitivity to soil moisture transmission. • Additional recommendations regarding water or vapor transmission should be provided by the architect/structural engineer/slab or foundation designer and should be consistent with the specified floor coverings indicated by the architect. Regardless of the mitigation, some limited moisture/moisture vapor transmission through the slab should be anticipated. Construction crews may require special training for installation of certain product(s), as well as concrete finishing techniques. The use of specialized product(s) should be approved by the slab designer and water-proofing consultant. A technical representative of the flooring contractor should review the slab and moisture retarder plans and provide comment prior to the construction of the foundations or improvements. The vapor retarder contractor should have representatives onsite during the initial installation. RETAINING WALL DESIGN PARAMETERS General GSI understands that the currently planned development includes below-grade building walls with maximum height that could reach 12 to 14 feet. The following section is for generalized geotechnical retaining wall recommendations on this site for the driveway access and below grade parking and elevator shaft (if applicable) walls. Recommendations for specialty walls, sound walls, or other specific cases, may be provided upon request. GSI anticipates that below grade walls will be either permanent shoring type (previously provided), cast-in-place, or concrete masonry block units (CMU) constructed in front of a slot cut or temporary shoring. All below grade retaining walls Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 29 a J I I I should be water-proofed, and utilize water stops. Waterproofing should also be provided for any site retaining walls in order to reduce the potential for efflorescence staining. Recommendations for waterproofing should be provided by a waterproofing consultant. Conventional Retaining Walls The design parameters provided below assume that either very low expansive soils (typically Class 2 permeable filter material or Class 3 aggregate base) or native onsite materials with an E.1. up to 20 and a P.l. less than 15 are used to backfill any retaining wall. Based on the available data, most of the onsite soils meet this criteria. The type of backfill (i.e., select or native), should be specified by the wall designer, and clearly shown on the plans. Preliminary Retaining Wall Foundation Design Preliminary foundation design for retaining walls should incorporate the following recommendations: Minimum Footing Embedment -Building retaining wall foundations should be embedded at least 30 inches below the lowest adjacent grade and bear on a minimum 2-foot thick layer of approved engineered fill overlying dense, unweathered old paralic deposits. Upon the structu,a:,eonsultant's discretion, foundations for building retaining walls may be incorporated into the mat foundation system recommended herein. Foundations for site retaining walls should be embedded at least 24 inches into approved engineered fill or unweathered old paralic deposits. Minimum Footing Width -24 inches Allowable Bearing Pressure -An allowable bearing pressure of 2,500 psf may be used in the preliminary design of building retaining wall foundations provided that the footing maintains a minimum width of 24 inches and extends at least 24 inches into approved engineered fill overlying dense, unweathered old paralic deposits. An allowable bearing pressure of 3,000 psf may be used in the preliminary design of site retaining wall foundations provided that the footing maintains a minimum width of 24 inches and extends at least 24 inches into dense suitable native soil. These pressures may be increased by one-third for short-term wind and/or seismic loads. Passive Earth Pressure -For a retaining wall foundation extending at least 30 inches into approved engineered fill, a passive earth pressure of 250 pcf with a maximum earth pressure of 2,500 psf may be used in the design. For retaining wall foundations extending at least 30 inches into approved engineered fill or dense suitable native soil, a passive earth pressure of 300 pcf with a maximum earth pressure of 3,000 psf may be used in the design. Mr. M ichaal Donovan 2646 State Street,. Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 30 .... 3 I I II j l~ 1 I I I I I I I :1 I Lateral Sliding Resistance -A 0.35 coefficient of friction may be utilized for a concrete to soil contact when multiplied by the dead load. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. Backfill Soil Density -Soil densities ranging between 105 pcf and 120 pcf may be used in the design of retaining wall foundations. This assumes an average engineered fill compaction of at least 90 to 95 percent of the laboratory standard (ASTM D 1557). Any site retaining wall footings near the perimeter of the site will likely need to be deepened into unweathered old paralic deposits. All footing setbacks from slopes should comply with Figure 1808.7.1 of the 2013 CBC. GSI recommends a minimum horizontal setback distance of 7 feet as measured from the bottom, outboard edge of the footing to the slope face. Foundations should also extend below a 1 :1 (h:v) projection up from the bottom outside edge of remedial grading excavations. Restrained Walls Any retaining walls that will be restrained prior to placing and compacting backfill material or that have re-entrant or male corners, should be designed for an at-rest equivalent fluid pressure (EFP) of 55 pcf and 65 pcf for select and very low expansive native backfill, respectively. The design should include any applicable surcharge loading. For areas of male or re-entrant corners, the restrained wall design should extend a minimum distance of twice the height of the wall (2H) laterally from the corner. Cantilevered Walls The recommendations presented below are for cantilevered retaining walls up to 19 feet high. Design parameters for walls less than 3 feet in height may be superceded by San Diego Regional Standard design. Active earth pressure may be used for retaining wall design, provided the top of the wall is not restrained from minor deflections. An equivalent fluid pressure approach may be used to compute the horizontal pressure against the wall. Appropriate fluid unit weights are given below for specific slope gradients of the retained material. These do not include other superimposed loading conditions due to traffic, structures, seismic events or adverse geologic conditions. When wall configurations are finalized, the appropriate loading conditions for superimposed loads can be provided upon request. For preliminary planning purposes, the structural consultant should incorporate the surcharge of traffic on the back of retaining walls where vehicular traffic will occur within a horizontal distance equal to "H" from the back of any retaining wall (where "H" equals the height of the retaining wall). The traffic surcharge for light passenger cars, light trucks, and vans may be taken as 100 psf/ft in the upper 5 feet of the backfill. For heavy emergency vehicle or multi-axle (HS20) truck traffic, the traffic surcharge should be 300 psf/ft in the upper 5 feet of the backfill. This does not include the surcharge of parked Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 31 ] ,J I '.·. )"· ' ' ,' I vehicles which should be evaluated at a higher surcharge to account for the effects of seismic loading. Footings from offsite improvements located above a 1 :1 (h:v) projection up from the heel of the wall footing should incorporate 0.35 times the bearing pressure of the footing. Stockpiled materials on adjacent properties located above a 1 :1 (h:v) projection up from the heel of the wall footing should be evaluated based on the type of materials and the duration of time the stockpile will be left in-place. Equivalent fluid pressures for the design cantilevered retaining walls are provided in the following table: SlJRfACE'SLGPE(ll:; RETAlfiEtf•~" HORIZONTAL~ ... Leve1<1l 2 to 1 ... EQWVALEN'{ff.OIO'WEIGHt .. ···"iP.C.f~•(SELECTPA~PRC>VED·.· .' . BAOKALL ~ > 38 50 48 65 <1) -Level backfill behind a retaining wall is defined as compacted earth materials, properly drained, without a slope for a distance of 2H behind the wall. <2l -E.I. .:'.£20, P.I. <15, SE .?_30, with <10% passing No. 200 sieve. <3l -E.I. <50 P.1. <15 SE >25 with 15% assin No. 200 sieve. Seismic Surcharge· For engineered retaining walls 6 feet or greater in overall height, retaining walls that are incorporated into a building, and/or retaining walls that may pose ingress or egress constraints to the residential structure, GSI recommends that the walls be evaluated for a seismic surcharge (in general accordance with 2013 CBC requirements). The site walls in this category should maintain an overturning Factor-of-Safety (FOS) of approximately 1.25 when the seismic surcharge (increment), is applied. For restrained walls, the seismic surcharge should be applied as a uniform surcharge load from the bottom of the footing , (excluding shear keys) to the top of the backfill at the heel of the wall footing. This seismic surcharge pressure (seismic increment) may be taken as 17H where "H" for retained walls is the dimension previously noted as the height of the backfill to the bottom of the footing. The resultant force should be applied at a distance 0.6 H up from the bottom of the footing. For the evaluation of the seismic surcharge, the bearing pressure may exceed the static value by one-third, considering the transient nature of this surcharge. For cantilevered walls the pressure should be an inverted triangular distribution using 17H. Please note that the evaluation of the seismic surcharge is for local wall stability only. The 17H is derived from a Mononobe-Okabe solution for both restrained cantilever walls. This accounts for the increased lateral pressure due to shakedown or movement of the sand fill soil in the zone of influence from the wall or roughly a 45° -<l>/2 plane away from the back of the wall. The 17H seismic surcharge is derived from the formula: Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 32 ... ~ J J ~ I '.I 11 I I 11 I D t ; I I I I I Ph=%• <Ii,• Y1H Where: Ph <Ii, Yt H = = = = Seismic increment Probabilistic horizontal site acceleration with a percentage of "g" Total unit weight (115 to 125 pcf for site soils @ 95% relative compaction). Height of the wall from the bottom of the footing or point of pile fixity. Retaining Wall Backfill and Drainage Onsite soil vary from very low to medium expansive. Criteria for backfill quality is presented in the preceding table. Positive drainage must be provided behind all retaining walls in the form of gravel wrapped in geofabric and outlets. A backdrain system is considered necessary for retaining walls that are 2 feet or greater in height. Details 1, 2, and 3, present the backdrainage options discussed below. Backdrains should consist of a 4-inch diameter perforated PVC or ABS pipe encased in either Class 2 permeable filter material or %-inch to 1 %-inch gravel wrapped in approved filter fabric (Mirafi 140 N or equivalent). The backdrain should flow via gravity (minimum 1 percent grade) toward an approved drainage facility. A sump pump will likely be necessary for below grade walls, and it should not saturate surrounding soils. For select backfill, the filter material should extend a minimum of 1 horizontal foot behind the base of the walls and upward at least 1 foot. For native backfill that has up to E.I. = 20, continuous Class 2 permeable drain materials should be used behind the wall. This material should be continuous (i.e., full height) behind the wall, and it should be constructed in accordance with the enclosed Detail 1 (Typical Retaining Wall Backfill and Drainage Detail). For limited access and confined areas, (panel) drainage behind the wall may be constructed in accordance with Detail 2 (Retaining Wall Backfill and Subdrain Detail Geotextile Drain). Materials with an E. I. potential of greater than 20 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). For below-grade building walls, GSI recommends that an impermeable membrane be placed beneath the wall subdrain and extend at least 2 feet above the basement finish-floor elevation on the exterior of the retaining wall and along the wall backcut in order reduce saturation of the bearing soils and migration of infiltrated water beneath the building foundation. Retaining wall backfill should be moisture conditioned to 1 .1 to 1 .2 times the soil's optimum moisture content, placed in relatively thin lifts, and compacted to at least 95 percent of the laboratory standard (ASTM D 155 7). Above grade outlets should consist of a 4-inch diameter solid PVC or ABS pipe spaced no greater than ± 100 feet apart, with a minimum of two outlets, one on each end. The use of weep holes, only, in above grade walls higher than 2 feet, is not recommended. Below grade walls should not utilize weep holes. The surface of the backfill should be sealed by pavement or the top 18 inches compacted with native soil (E.I. ~ 50). Proper surface drainage should also be provided. For additional mitigation, consideration should be given Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 33 "'' J J i~ I I I 11 1 ll I I 1 • 11 ' i I I I I I I (1) Waterproofing membrane-~ Structural footing or settlement-sensitive improvement Provide surface drainage via an engineered V-ditch (see civil plans for details) 2=1 (h:v) slope CMU or reinforced-concrete wall ·. ·:-... : .. \ ...... · . •.• .... . 1-----· ••, > : , ~ $1~•.?:·~vel \". , J <: .·· Proposed grade t - sloped to drain per precise civil drawings (5) Weep hole ~~~~\%~ Footing and wall design by others1.......L:....~ (1) Waterproofing membrane. (2) Gravel= Clean, crushed, % to 1~ inch. (3) Filter fabric: Mirafi 140N or approved equivalent. . . Native backfill 1=1 (h:v) or flatter backcut to be properly benched (6) Footing (4) Pipe: 4-inch-diameter perforated PVC, Schedule 40, or approved alternative with minimum of 1 percent gradient sloped to suitable, approved outlet point (perforations down). (5) Weep 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: H 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 J J ; 'I m n C D u C I I i I I :, 1• (1) Waterproofing membrane (optional)-- CMU or reinforced-concrete wall l 6 inches 1- (5) Weep hole Proposed grade sloped to drain per precise civil drawings //\~\\'§(\~~\'))5\\((\ Footing and wall design by others~- Str.uctwat footing or settlement-sensitive improvement Provide surface drainage via engineered V-ditch (see civil plan details) 2:1 (h:v) slope Native backfill 1:1 (h=v) or flatter backcut to be properly benched ----(6) 1 cubic foot of %-inch crushed rock (7) Footing (1) Waterproofing membrane (optional): Liquid boot or approved mastic equivalent. (2) Drain= Miradrain 6000 or J-drain 200 or equivalent for non-waterproofed walls; Miradrain 6200 or J-drain 200 or equivalent for waterproofed walls (all perforations down). (3) Filter fabric= Mirafi 140N or approved equivalent; place fabric flap behind core. (4) Pipe= 4-inch-diameter perforated PVC, Schedule 40, or approved alternative with minimum of 1 percent gradient to proper outlet point (perforations down). 4 (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) Gravel= Clean, crushed, % to 1-"2 inch. (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. RETAINING WALL DETAIL -ALTERNATIVE B Detail 2 ..... (1) Waterproofing membrane-~ CMUor reinforced-concrete wall ---=t ±12 inches l (5) Weep hole H [Proposed grade sloped to drain per precise civil drawir19~ <~0\\X\\~\~ Footing and wall design by others Structural footing or settlement-sensitive improvement r----Provide surface drainage 2=1 (h=v) slope . . ;'... : ... · .. . · ... ... ·:·: .. : . . ...... ·:· .· ', ,__ ____ ; . :', : : is~ .;, ·~~~I -:, ; ·: i . '. .::~: ~:. --.: .••.. :.:::·:.; )_:~, (3) Filter fabric (2) Gravel (4) Pipe (8) Native backfill (6) Clean sand backfill 1=1 (h=v) or flatter backcut to be properly benched (7) Footing (1) Waterproofing membrane= Liquid boot or approved masticequivalent. (2) Gravel= Clean, crushed, % to 1~ inch. (3) Filter fabric= Mirafi 140N or approved equivalent. (4) Pipe= 4-inch-diameter perforated PVC, Schedule 40, or approved alternative with minimum of 1 percent gradient to proper outlet point (perforations down). (5) Weep hole= 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 tikely be required by geotechnical consultant. (8) Native backfill: If E.1. <21 and S.E. l35 then all sand requirements also may not be required and will be reviewed by the geotechnical consultant. RETAINING WALL DETAIL -ALTERNATIVE C Detail 3 - J I I ii to applying a water-proof membrane to the back of all retaining structures. The use of a waterstop should be considered for all concrete and masonry joints. Wall/Retaining Wall Footing Transitions Site walls are anticipated to be founded on footings designed in accordance with the recommendations in this report. Should wall footings transition from cut to fill, the civil designer may specify either: a) A minimum of a 2-foot overexcavation and recompaction of cut materials for a distance of 2H, from the point of transition. b) Increase of the amount of reinforcing steel and wall detailing (i.e., expansion joints or crack control joints) such that a angular distortion of 1 /360 for a distance of 2H on either side of the transition may be accommodated. Expansion joints should be placed no greater than 20 feet on-center, in accordance with the structural engineer's/wall designer's recommendations, regardless of whether or not transition conditions exist. Expansion joints should be sealed with a flexible, non-shrink grout. c) Embed the footings entirely into native formational material (i.e., deepened footings). If transitions from cut to fill transect the wall footing alignment at an angle of less than 45 degrees (plan view), then the designer should follow recommendation "a" (above) and until such transition is between 45 and 90 degrees to the wall alignment. SHORING WALLS Shoring of Excavations Based on the proximity of adjacent property to the currently planned excavation, shoring walls appear necessary. If allowed, the use of tie-back anchors would assist in reducing the size of soldier piles. Shoring of excavations of this size (i.e., approximate maximum height equivalent to ± 14 feet considering planned excavations to pad grade plus foundation embedment) is typically performed by specialty contractors with knowledge of the City of Carlsbad ordinances, and current building codes, as well as the local area soil conditions. Since the design of retaining systems is sensitive to surcharge pressures behind the excavation, we recommend that this office be consulted if unusual load conditions are uncovered in the placement/installation. To that end, GSI should perform field reviews during shoring construction. This would include geologic logging of selected drilled shafts. Care should be exercised when excavating into the on-site soils since caving or sloughing of the earth materials is possible, especially near the perched groundwater table encountered at approximate depths of 10 to 12 feet (±27 to 30 feet MSL) below the Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.0. 6935-A-SC November 3, 2015 Page 37 - J 1 i existing grades (±39 to 40 feet MSL), during our subsurface investigation. Thus, casing of drilled shafts may be necessary during soldier pile installation. In addition, drilled excavations extending into the Santiago Formation may encounter some difficulty and the localized use of a core barrel cannot be entirely precluded. Observation of soldier pile excavations and special inspections/testing should be performed during shoring construction. Shoring of the excavation is the responsibility of the contractor. Extreme caution should be used to reduce damage to the existing building or any other adjacent property caused by settlement or reduction of lateral support. Accordingly, we recommend a system of surveying and monitoring until the permanent building walls are constructed and backfilled to the design grade in order to evaluate the effects of shoring on existing onsite and offsite improvements. Pre-construction photo-documentation is also advisable. Unless incorporated into the shoring design, construction equipment storage or traffic, and/or stockpiles should not be stored or operated within 'H' feet of the top of any shored excavations (where 'H' equals the height of the retained earth). Temporary/permanent provisions should be made to direct any potential runoff away from the top of shored excavations. All applicable surcharges from vehicular traffic and existing structures within 'H' of a shored excavation should be evaluated. Lateral Earth Pressures for Shoring Design 1. The active pressure to be utilized for shoring design may be computed by the triangular pressure distribution shown in Figure 2 (temporary shoring) or Figure 3 (permanent shoring). This assumes level backfill conditions within 11H" feet of the shoring wall, where "H 11 equals the height of the shoring wall. 2. Passive pressure may be computed as an equivalent fluid having a given density shown in Figure 2 (temporary shoring) or Figure 3 (permanent shoring). 3. the above criteria assumes that hydrostatic pressure is not allowed to build up behind shoring walls. Should seepage be encountered, wall faces should receive blind-side gee-composite drain panels consisting of Mirafi G1 OOW (or approved equivalent) connected to a 4-to 6-inch diameter solid drain pipe at the base of the wall. 4. These recommendations are for excavation walls up to 14 feet high. An empirical equivalent fluid pressure approach may be used to compute the horizontal pressure against the wall. Appropriate fluid unit weights are provided for specific slope gradients of the retained material; these do not include other superimposed loading conditions such as traffic, structures, seismic events, expansive soils or adverse geologic conditions. For relatively stiff permanent shoring walls greater than 6 feet in height, a seismic increment of 17H (uniform pressure [psf/ft]) may be considered for restrained, level backfill conditions. A similar seismic increment may be used in the design for cantilevered shoring walls with level backfill conditions. However, the seismic increment should be applied as an inverted triangular distribution. The Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 38 J I I Cantilever Shorir,g Sy~tem ® Temporary 1:1 (H:V) Slope up to 3 feet . Surcharge Pressure P (psf) t ' Line Load QL(pounds) 3' 19'-0" H (feet)=16 X - 0.1 Y (feet) 0.3 0.5 0.7 X R 35 H (psf) H ~0.4 0.55QL >0.4 ( o.64 aL) x2+ 1 I· 400 D (psf) · I Ti~-Back Shoril}g §ystem 0.2 H (ft.) __L H (feet) 0.35 P (psf) Surcharge Pressure P (psf) Line Load a L (pounds) .. Resistance behind this line Minimum 7' depth for supporting piers H }(feet) NOTES I· 400 D (psf) ©·I ·27 H (psfrl@ 0.35 P (psf) '881· Include groundwater effects below groundwater level. Include water effects below groundwater level. y 0.6H 0.6H 0.56H 0.48H Y (feet) G) ® ® © ® Grouted length greater than 7 feet; field test anchor strength. Neglect passive pressure below base of excavation to a depth of one pier diameter. LATERAL EARTH PRESSURES FOR TEMPORARY SHORING SYSTEMS 1:1 (H:V) Slope, broken slope backfill up to 3 feet high above shoring with a minimum Ka=1.35" W.O. 6935-A-SC Figure 2 · DATE: 11/15 SCALE: None - .., J _ -Surcharge Pressure P (psf) Cantilever Shoring System r i--,..,......\---i---Line Load OL (pounds) ·xH \ ' H (feet) Y (feet) X R X 0.1 0.3 0.5 0.7 45 H (psf) I· 300 D (psf) · I H 0.35 P (psf) i0.4 0.55 OL )0.4 (0.64 OQ x2+ 1 } Tie-Back Shoring System _ -Surcharge Pressure P (psf) t \ ---Line Load O L (pounds) H (feet) --Minimum 7' depth f~ supporting H i-----,--,----i--..,,,...-.~--.-ipl® 0.35 P (psf) 300 D (psf) @) 35 H (psf) NOTES © Include groundwater effects below groundwater level «&SI· y 0.6H 0.6H 0.56H 0.48H Y (feet) ® Include water effects below groundwater level ® © Grouted length greater than 7 feet; field test anchor strength. LATERAL EARTH PFESSURES Fal PBIWBIT K1ll1 SYS1EM8 Figure 3 Neglect passive pressure below base of excavation to a depth of 1--------------------1 one pier diameter. W.Q 6935-A-SC DA1& 11/15 a:::AlB None ... ' • I 'I J 5. 6. seismic load should be applied at 0.6H up from the point of fixity to the height of retained earth materials. This complies with a 0.460g Peak Horizontal Ground Acceleration (PGAM). The resulting wall design should be safe from seismic-induced overturning with a minimum factor-of-safety (F .O.S.) of 1.25. Traffic surcharges for permanent shoring walls should be minimally applied as 100 psf per lineal foot for light vehicular traffic and 300 psf for heavy emergency equipment (HS20) vehicular traffic in the upper 5 feet of the permanent shoring wall(s) if traffic is within 'H' of the back of the wall. It is not recommended to allow sloping surcharge (other than level backfill) within H behind the shored walls from either stockpiled soils or temporary/permanent graded slopes. Steeper slope gradients (more than level) will increase the EFP for shoring design significantly and more importantly, the cost of the shoring system. Surcharge loads from adajcent structures, notably the perimeter wall and offsite traffic pavement on the north side ofteh site, and the existing building on the suoth side of the site should be included in shoring design. The shoring system should be designed such that the maximum lateral deformation at the top of the soldier pile does not exceed 1 inch. The maximum lateral deformation for the drilled pile concrete shafts at the lowest grade level should not exceed % inch. Owing to the anticipated large height of portions of the shoring wall, a braced or tie- back shoring system may be necessary. Tie-back supports may not be feasible without permission from adjacent property owners. The feasibility of using tie-back supports should be based on a precise survey of all existing and planned improvements within the backfill by the project civil consultant and inquiries from with adjacent property owners. A rakered/braced shoring system appears more feasible. For temporary supports, a maximum allowable bearing of 3,000 psf may be used for a raker footing that is 12 inches wide by 30 inches deep into unweathered old paralic deposits. The design of the raker footing may incorporate a passive pressure of 300 pcf. The raker footing bearing value may be increased by 20 percent for each additional foot of depth to a maximum of 4,000 psf. The coefficient of friction between concrete and soils should be 0.35 when combined with the dead load forces. Shoring Vertical Bearing -Temporary and Permanent Walls GSI has assumed that shoring walls will consist of a reinforced cast-in-drilled-hole (CIDH) piles with minimum diameters ranging between 24 to 48 inches that are embedded "H" feet into unweathered old paralic deposits, or Santiago Formation where "H" equals the height of the shoring structure. Vertical bearing of the shoring H-piles encased in concrete will be gained by friction within the formation (i.e., unweathered old paralic deposits and Santiago Formation) and end bearing of the pile. Minor down-drag due to settlement will not impose a significant load to the pile-supported temporary or permanent shoring, as this settlement is anticipated to be less than 1 inch. Vertical pile support for the portion of the piles (H-piles) embedded in the formation will be gained by adhesion of the bedrock to the Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 41 - I ii 11 ·I I I I I I iD j, 'I I I ii ii I I pile surface, as well as end-bearing on the piles. If the bottoms of the drilled shafts are relatively clean of loose soil prior to the placement of steel and concrete into the shaft excavation, the designer may utilize a 4,000 psf bearing on the end surface of the pile hole in formation. If the hole is left in a loose condition or the temporary shoring design does not need end bearing for vertical support, this end bearing should be neglected in the design. Another component of the vertical bearing of the drilled pile support for the temporary shoring will come from the adhesion of the formation against the concrete. This will provide up to 300 psf of adhesion for a formational materials consisting of silty to clayey sands. This should be applied over the surface area of the pile embedded into the formation, excluding the end or return wall. Due to the primarily lateral loads on the pile, this will likely provide sufficient support from a vertical load standpoint, which should be confirmed by the shoring designer. When considering nearby improvements located above a 1 :1 (h:v) projection up from the toe of the shored excavation, GSI recommends that a Boussinesq approach be considered in the shoring design. This approach may model the loads for an estimated vertical load of a footing or traffic loads, and may be used as a line load on the back of the shoring. A seismic increase of the footing by one-third of the estimated bearing load should be considered. Tie-Backs Anchors If permitted, tie-back anchors would serve to reduce pile loads for the shoring wall. GSI has estimated that 24-and 48-inch diameter CIDH piles for a free-head lateral capacity. If a grade beam is used and confined by slabs, this may be considered a fixed-head condition. Once actual pile loads are provided, these evaluations should be reconsidered. The lateral pile deflection under static soil and structural loads should be limited to 1-inch, or less. , When considering the height of the permanent shoring condition and our evaluation using (Anderson, et al., 1994), we estimate that settlement behind the shoring wall may be on the order of 1 to 2 inches without tie-backs. If this magnitude of settlement is unacceptable or would cause damage to existing improvements/property in the retained zone, tie-backs may be incorporated into the shoring wall (if permitted). Properly designed tie-backs would likely reduce the deflection of the soldier piles to % inch or less. If permitted, this office could provide design recommendations for tie-back anchors used in conjunction with shoring walls. Shoring Construction Recommendations 1. The excavations for the installation of the soldier piles should be observed and documented by the project geotechnical engineer to further evaluate the geologic conditions within the influence of the shoring wall and-to ensure the soldier pile construction conforms to the requirements of the shoring plan 2. Drilled excavations for soldier piles should be straight and plumb. If boulders, cobbles, or concretions are encountered during drilling, the contractor should periodically recheck the drilled shaft for plumbness. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a,gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 42 I I 3. 4. Casing should be provided in drilled shafts if excessive perched water and/or caving conditions be encountered during drilling operations. The bottom of the casing should be at least 4 feet below the top of the concrete as the concrete is poured and the casing is withdrawn. Dewatering may be required for concrete placement if significant seepage or groundwater is encountered during construction. This should be considered during project planning. The exact tip elevation of the soldier piles should be clearly indicated on the shoring plans. 5. Proper spacing (minimum of 3 inches) between steel reinforcement and the side walls, and bottoms of the drilled shafts should be provided. 6. Concrete used in the shoring construction should be tested by a qualified materials testing consultant for strength and mix design. 7. Excavation for lagging should not commence until the soldier pile concrete reaches its 28-day compressive strength. 8. A complete and accurate record of all soldier pile locations, depths, concrete, strengths, quantity of concrete per pile should be maintained by the special inspector and geotechnical consultant. The shoring design engineer should be notified of any unusual conditions encountered during installation. Alternating Slot Excavations Upon approval of the shoring designer, alternating ("A', "B", and "C") slot excavations may be conducted adjacent to the shoring wall to perform remedial earthwork without increasing the shoring height. Additional information regarding this alternative can be provided upon request. Monitoring of Shoring 1 . The shoring designer or his designee should make periodic inspections of the job site for the purpose of observing the installation of the shoring system and monitoring of survey. 2. Monitoring points should be established at the top of selected soldier piles and at intermediate intervals as considered appropriate by the Geotechnical Engineer. 3. Control points should be established outside the area of influence of the shoring system to ensure the accuracy of the monitoring readings. 4. Initial monitoring and photo-documentation should be performed prior to any excavation. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 43 J J i] jl 11 I~ ,~ IJ I -! J J ] 5. 6. 7. 8. Once the excavation has commenced, periodic readings should be taken weekly until the permanent retaining wall is constructed and backfilled to the design grade. If the performance of the shoring system is within established guidelines, the shoring engineer may permit the periodic readings to be bi-weekly. Permission to conduct bi-weekly readings should be provided by the shoring design engineer in writing, and be distributed to the Geotechnical Engineer-of-Record, Structural Engineer-of-Record, Civil Engineer-of-Record, and shoring contractor. Once initiated, bi-weekly readings should continue until the permanent retaining wall is backfilled to the design grade. Thereafter, readings can be made monthly. Additional readings should be taken when requested by the special inspector, Shoring Design, Engineer, Structural Engineer-of-Record, Geotechnical Engineer-of-Record, or the Building Official. Monitoring reading should be submitted to the Shoring Design Engineer, Engineer in Responsible Charge, and the Building Official within three business days after they are conducted. Monitoring readings should be accurate to within 0.01 feet. Results are to be submitted in tabular form showing at least the initial date of monitoring and reading, current monitoring date and reading and difference between the two readings. If the total cumulative horizontal or vertical movement (from start of shoring construction) of the existing building reaches %-inch or soldier piles reaches 1 inch, all excavation activities should be suspended until the Geotechnical Engineer and Shoring Design Engineer determine the cause of movement and provide corrective measures, as necessary. Excavation should not re-commence until written permission is provided by the Geotechnical Engineer and Shoring Design Engineer. If the total cumulative horizontal or vertical movement (from start of shoring construction) of any nearby existing improvement reaches %-inch or soldier piles reaches 1 inch, all excavation activities should be suspended until the Geotechnical Engineer and Shoring Design Engineer determine the cause of movement. Supplemental shoring should be devised to eliminate further movement. Supplemental shoring design will require review and approval by the Building Official. Excavation should not re-commence until written permission is provided by the Building Official. Monitoring of Structures Prior to, During, and Post-Shoring Construction and Excavation 1. The contractor should complete a written and photographic log of existing buildings or other structures located within 100 feet or three times the depth of shoring (whichever is greater) prior to shoring construction. A licensed surveyor should document all existing substantial cracks (i.e., greater than 1/a-inch horizontal or vertical separation) in adjacent buildings and structures. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp 12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 44 J l J I jl . 1, 1. I I I 2. 3. 4. 5. 6. 7. 8. The contractor should document the existing condition of wall cracks in existing buildings adjacent to the shoring wall prior to the start of shoring construction. The contractor should monitor existing building walls and improvements for movement or cracking that may result from the adjacent shoring. If excessive movement or visible cracking occurs, the shoring contractor should stop work and shore/reinforce the excavation, and contact the Shoring Design Engineer and the Building Official. Monitoring of existing buildings or adjacent structures should be made at reasonable intervals and no more than a monthly basis as required by the registered design professional, subject to approval by the Building Official. Monitoring should be performed by a licensed surveyor. Consideration should be given to adding digital video records of the onsite and adjacent site conditions prior to construction. Prior to commencing shoring construction, a pre-construction meeting should take place between the contractor, Shoring Design Engineer, Surveyor, Geotechnical Engineer, and the Building Official to identify monitoring locations on existing buildings and adjacent improvements. If in the opinion of the Building Official or Shoring Design Engineer, monitoring data indicate excessive movement or other distress, all excavation should cease until the Geotechnical Engineer and Shoring Design Engineer investigates the situation and makes recommendations for remedial actions or continuation. All readings and measurements should be submitted to the Building Official and Shoring Design Engineer. PRELIMINARY PORTLAND.CEMENT CONCRETE PAVEMENT (PCCP) DESIGN RECOMMENDATIONS The preliminary design for parking garage ingress/egress lane and parking garage drive lane, and parking stall PCCP was evaluated using the pavement software PCAPAV. Our evaluation considered a modulus of subgrade reaction (Ks) equivalent to 100 pounds per cubic inch (pci), a modulus of rupture (MR) of 520 pounds per square inch (psi), the absence of concrete shoulders and dowels for the parking garage ingress/egress lanes, and the inclusion of concrete shoulders and dowels for the parking garage drive lanes, and parking stalls. A load safety factor of 1.2 was applied to the parking garage ingress/egress lanes and a load safety factor of 1 .1 was applied to the parking garage drive lanes and parking stalls. An average daily truck traffic (ADTT) value of 5 was also considered in our evaluation. GSI does not practice in the field of traffic engineering. Thus, the actual ADTT should be provided by a licensed traffic engineer or licensed civil engineer specializing in Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 45 , .... •• """' 111111 •• J I I I traffic engineering. PCCP was evaluated for a 20-year design life. Based on our analysis, the PCCP sections are provided in the following table: Parking Garage Stalls 560-C-3250 6.5 inches Parking Garage Drive Lanes 560-C-3250 7inches 560-C-3250 Sinches NOTE: All PCCP is designed as un-reinforced and bearing directly on subgrade compacted to at least 90 percent of the laboratory standard (ASTM D 1557). However, a 4-inch thick leveling course of compacted aggregate base, or crushed rock may be considered to improve performance. All PCCP should be properly detailed Oointing, etc.) per the industry standard. Pavements should be additionally reinforced with #4 reinforcing bars, placed 12 inches on center, each way, for improved performance. Trash truck loading pads shall be 8 inches per the City standard reinforced accordingly. Concrete cut-off walls or thickened PCCP edges should be considered where PCCP is adjacent to landscaping. The cut-off wall of thickened edge should be at least 6 inches wide and extend at least 12 inches below the PCCP subgrade. No traffic should be allowed upon the newly poured concrete slabs until they have been properly cured to within 75 ercent of desi n stren th. Concrete compression stren th should be a minimum of 3,250 psi Repair or replacement of any existing asphaltic concrete pavements within State Street should be performed in accordance with City of Carlsbad standards. PORTLAND CEMENT CONCRETE (PCC) FLATWORKAND OTHER IMPROVEMENTS The soil materials on site may be expansive. The effects of expansive soils are cumulative, and typically occur over the lifetime of any improvements. On relatively level areas, when the soils are allowed to dry, the dessication and swelling process tends to cause heaving and distress to flatwork and other improvements. The resulting potential for distress to improvements may be reduced, but not totally eliminated. To that end, it is important that the developer be aware of this long-term potential for distress. To reduce the likelihood of distress, the following recommendations are presented for all exterior flatwork: 1. The subgrade area for non-vehicular concrete slabs should be moisture conditioned to at least optimum moisture content and then compacted to achieve a minimum 90 percent of the laboratory standard (ASTM D 1557). Although not anticipated, if expansive soils (E.I. > 20) are present, the subgrade should be moisture conditioned to at least 2 to 3 percentage points above optimum moisture content and then be compacted to achieve a minimum 90 percent of the laboratory standard (ASTM D 1557). Concrete should be placed within 72 hours of subgrade preparation provided there is written approval of the subgrade by the geotechnical consultant. Mr.M~haelDonovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 46 uiill 2. 3. 4. 5. 6. 7. 8. 9. Concrete slabs should be cast over a non-yielding surface, consisting of a 4-inch layer of crushed rock, gravel, or clean sand, that should be compacted and level prior to pouring concrete. If very low expansive soils are present, the rock or gravel or sand may be deleted. The layer or subgrade should be wet-down completely prior to pouring concrete, to minimize loss of concrete moisture to the surrounding earth materials. Exterior slabs should be a minimum of 4 inches thick. Driveway approach slabs should be deigned and constructed in accordance with City of Carlsbad standards. The use of transverse and longitudinal control joints are recommended to help control slab cracking due to concrete shrinkage or expansion. Two ways to mitigate such cracking are: a) add a sufficient amount of reinforcing steel, increasing tensile strength of the slab; and, b) provide an adequate amount of control and/or expansion joints to accommodate anticipated concrete shrinkage and expansion. In order to reduce the potential for unsightly cracks, slabs should be reinforced at mid-height with a minimum of No. 3 bars placed at 18 inches on center, in each direction. If subgrade soils within the top 7 feet from finish grade are very low expansive soils (i.e., E.I. ~20), then 6x6-W1 .4xW1 .4 welded-wire mesh may be substituted for the rebar, provided the reinforcement is placed on chairs, at slab mid-height. The exterior slabs should be scored or saw cut, % to 3/a inches deep, often enough so that no section is greater than 10 feet by 10 feet. For sidewalks or narrow slabs, control joints should be provided at intervals of every 6 feet. The slabs should be separated from the foundations and sidewalks with expansion joint filler material. Concrete compression strength for non-vehicular slabs, outside the building footprint, may be a minimum of 2,500 psi. Driveways, sidewalks, and patio slabs adjacent to the building should be separated from the building with thick expansion joint filler material. In areas directly adjacent to a continuous source of moisture (i.e., irrigation, planters, etc.), all joints should be additionally sealed with flexible mastic. Planters and walls should not be structurally tied to the building. 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. 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. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 47 :] J J ii I I 'i m ~. ' lffll!!t ,,,., i 11,111 11ilM I I I 1 O. Utilities should be enclosed within a closed utilidor (vault) or designed with flexible connections to accommodate differential settlement or expansive soil conditions. 11. Positive site drainage should be maintained at all times. Finish grade on the lot should provide a minimum of 1 to 2 percent fall to the street, as indicated herein. It should be kept in mind that drainage reversals could occur, including post-construction settlement, if relatively flat yard drainage gradients are not periodically maintained by the owner or owner's association. Surface drainage in excess of 2 percent in untreated fill soils is not recommended due to the low plasticity and increased erosion potential. 12. Air conditioning (A/C) units should be supported by slabs that are incorporated into the building foundation or constructed on a rigid slab with flexible couplings for plumbing and electrical lines. NC waste water lines should be drained to a suitable non-erosive outlet. 13. Shrinkage cracks could become excessive if proper finishing and curing practices are not followed. Finishing and curing practices should be performed per the Portland Cement Association Guidelines. Mix design should incorporate rate of curing for climate and time of year, sulfate content of soils, corrosion potential of soils, and fertilizers used on site. ONSITE INFILTRATION-RUNOFF RETENTION SYSTEMS General If onsite i'nfiltration-runoff retention systems (OIRRS), including vegetated swales, are planned for Best Management Practices (BMP's) or Low Impact Development (LID) principles for the project, some guidelines should/must be followed in the planning, design, and construction of such systems. Such facilities, if improperly designed or implemented without consideration of the geotechnical aspects of site conditions,. can contribute to flooding, saturation of bearing materials beneath site improvements, slope instability, and possible concentration and contribution of pollutants into the groundwater or storm drain and/or utility trench systems. A key factor in these systems is the infiltration rate (often referred to as the percolation rate) which can be ascribed to, or determined for, the earth materials within which these systems are installed. Additionally, the infiltration rate of the designed system (which may include gravel, sand, mulch/topsoil, or other amendments, etc.) will need to be considered. The project infiltration testing is very site specific, any changes to the location of the proposed OIRRS and/or estimated size of the OIRRS, may require additional infiltration testing. GSI anticipates that relatively impermeable earth materials and non-detrimentally expansive fill soils will be exposed at the conclusion of grading. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 48 ... , Some of the methods which are utilized for onsite infiltration include percolation basins, dry wells, bio-swale/bio-retention, permeable pavers/pavement, infiltration trenches, filter boxes and subsurface infiltration galleries/chambers. Some of these systems are constructed using native and import soils, perforated piping, and filter fabrics while others employ structural components such as stormwater infiltration chambers and filters/separators. Every site will have characteristics which should lend themselves to one or more of these methods; but, not every site is suitable for OIRRS. In practice, OIRRS are usually initially designed by the project design civil engineer. Selection of methods should include (but should not be limited to) review by licensed professionals including the geotechnical engineer, hydrogeologist, engineering geologist, project civil engineer, landscape architect, environmental professional, and industrial hygienist. Applicable governing agency requirements should be reviewed and included in design considerations. The following geotechnical guidelines should be considered when designing onsite infiltration-runoff retention systems: • Based on our review of the soil survey maps and information provided by the United States Department of Agriculture (http://websoilsurvey.sc.egov.usda.gov/ App/WebSoilSurvey.aspx), the onsite soils sonsist of the Marina loamy course sand, 2 to 9 percent slopes. The United States Department of Agriculture (USDA) indicates that the capacity of the most limiting layer to transmit water (Ksat) for this mapped soil unit is moderately high to high (0.57 to 1 .98 inches per hour [in/hr]) The USDA also indicates that the Hydrologic Soil Group (HSG) designation for this mapped soils unit in HSG "B" which are relatively amenable to infiltration. However, based on our experience with sites underlain by similar earth materials, GSI estimates that the onsite soils are more consistent with HSG "D" soils which have very slow infiltration rates when thoroughly wet. Infiltration in HSG "D" soils may be infeasible, and perched groundwater may be as shallow as 10 feet below existing grade. • • • Based on the existing soil conditions, GSI strongly recommends that if any required storm water treatment BMP is provided, it utilize impermeable liners, and subdrains along the bottom of below grade building walls/foundations to direct subsurface water to a suitable outlet/sump pump. It is not good engineering practice to allow water to saturate soils, especially near slopes or improvements; however, the controlling agency/authority is now requiring this for OIRRS purposes on many projects. If infntration is planned, infiltration system design should be based on actual infiltration testing results/data, preferably utilizing double-ring infiltrometer testing (ASTM D 3385) to determine the infiltration rate of the earth materials being contemplated for infiltration. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 49 I ''II! .J J l :J :1 J ;1 • • • • • • • • • Wherever possible, infiltration systems should not be installed within ±50 feet of the tops of slopes steeper than 15 percent or within H/3 from the tops of slopes (where H equals the height of slope). Wherever possible, infiltrations systems should not be placed within a distance of H/2 from the toes of slopes (where H equals the height of slope). Impermeable liners and subdrains should be used along the bottom of bioretention swales/basins located within the influence of slopes. Impermeable liners and subdrains should be used along the bottom of bioretention swales/basins located within the influence of slopes. Impermeable liners used in conjunction with bioretention basins should consist of a 30-mil polyvinyl chloride (PVC) membrane that is covered by a minimum of 12 inches of clean soil, free from rocks and debris, with a maximum 4:1 (h:v) slope inclination (where inundated), or flatter, and meets the following minimum specifications: Specific Gravity (ASTM D792): 1.2 (g/cc, min.); Tensile (ASTM D882): 73 (lb/in-width, min); Elongation at Break (ASTM D882): 380 (%, min); Modulus (ASTM D882): 32 (lb/in-width, min.); and Tear Strength (ASTM D1004): 8 (lb/in, min); Seam Shear Strength (ASTM D882) 58.4 (lb/in, min); Seam Peel Strength (ASTM D882) 15 (lb/in, min). Subdrains used in bioretention basins should consist of at least 4-inch diameter Schedule 40 or SDR 35 drain pipe with perforations oriented down. The drain pipe should be sleeved with a filter sock. The landscape architect should be notified of the location of the proposed OIRRS . If landscaping is proposed within the OIRRS, consideration should be given to the type of vegetation chosen and their potential effect upon subsurface improvements (i.e., some trees/shrubs will have an effect on subsurface improvements with their extensive root systems). Over-watering landscape areas above, or adjacent to, the proposed OIRRS could adversely affect performance of the system. Areas adjacent to, or within, the OIRRS that are subject to inundation should be properly protected against scouring, undermining, and erosion, in accordance with the recommendations of the design engineer. Seismic shaking may result in the formation of a seiche which could potential overtop the banks of an OIRRS and result in down-gradient flooding and scour. If subsurface infiltration galleries/chambers are proposed, the appropriate size, depth interval, and ultimate placement of the detention/infiltration system should be evaluated by the design engineer, and be of sufficient width/depth to achieve optimum performance, based on the infiltration rates provided. In addition, proper Mr.M~haelDonovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 50 Jll/1 •• J ,l I J I I I I I I I ll II Ii I I I I I • • • • • • • • • debris filter systems will need to be utilized for the infiltration galleries/chambers. Debris filter systems will need to be self cleaning and periodically and regularly maintained on a regular basis. Provisions for the regular and periodic maintenance of any debris filter system is recommended and this condition should be disclosed to all interested/affected parties. Infiltrations systems should not be installed within ±8 feet of building foundations utility trenches, and walls, or a 1 :1 (h:v) slope (down and away) from the bottom elements of these improvements. Alternatively, deepened foundations and/or pile/pier supported improvements may be used. Infiltrations systems should not be installed adjacent to pavement and/or hardscape improvements. Alternatively, deepened/thickened edges and curbs and/or impermeable liners may be utilized in areas adjoining the OIRRS. As with any OIRRS, localized ponding and groundwater seepage should be anticipated. The potential for seepage and/or perched groundwater to occur after site development should be disclosed to all interested/affected parties. Installation of infiltrations systems should avoid expansive soils (E.I. ~51) or soils with a relatively high plasticity index (P.I. > 20). Infiltration systems should not be installed where the vertical separation of the groundwater level is less than ± 1 O feet from the base of the system. Where permeable pavements are planned as part of the system, the site Traffic Index (T.I.) should be less than 25,000 Average Daily Traffic (ADT), as recommended in Allen, et al. (2011). Infiltration systems should be designed using a suitable factor of safety (FOS) to account for uncertainties in the known infiltration rates (as generally required by the controlling authorities), and reduction in performance over time. As with any OIRRS, proper care will need to be provided. Best management practices should be followed at all times, especially during inclement weather. Provisions for the management of any siltation, debris within the OIRRS, and/or overgrown vegetation (including root systems) should be considered. An appropriate inspection schedule will need to adopted and provided to all interested/affected parties. Any designed system will require regular and periodic maintenance, which may include rehabilitation and/or complete replacement of the filter media (e.g., sand, gravel, filter fabrics, topsoils, mulch, etc.) or other components utilized in construction, so that the design life exceeds 15 years. Due to the potential for piping and adverse seepage conditions, a burrowing rodent control program should also be implemented onsite. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 51 ''" I I • • • • • All or portions of these systems may be considered attractive nuisances. Thus, consideration of the effects of, or potential for, vandalism should be addressed. Newly established vegetation/landscaping (including phreatophytes) may have root systems that will influence the performance of the OIRRS or nearby LID systems. The potential for surface flooding, in the case of system blockage, should be evaluated by the design engineer. Any proposed utility backfill materials (i.e., inlet/outlet piping and/or other subsurface utilities) located within or near the proposed area of the OIRRS may become saturated. This is due to the potential for piping, water migration, and/or seepage along the utility trench line backfill. If utility trenches cross and/or are proposed near the OIRRS, cut-off walls or other water barriers will need to be installed to mitigate the potential for piping and excess water entering the utility backfill materials. Planned or existing utilities may also be subject to piping of fines into open-graded gravel backfill layers unless separated from overlying or adjoining OIRRS by geotextiles and/or slurry backfill. The use of OIRRS above existing utilities that might degrade/corrode with the introduction of water/seepage should be avoided. • A vector control program may be necessary as stagnant water contained in OIRRS may attract mammals, birds, and insects that carry pathogens. DEVELOPMENT CRITERIA Drainage Adequate 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 mitigate ponding of water anywhere on the property, and especially near structures and tops of slopes. Surface drainage should be carefully taken into consideration during fine grading, landscaping, and building construction. Therefore, care should be taken that future landscaping or construction activities do not create adverse drainage conditions. Positive site drainage within the property 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 tops of slopes, and not allowed to pond and/or seep into the ground. In general, site drainage should conform to Section 1804.3 of the 2013 CBC. Consideration should be given to avoiding construction of planters adjacent to structures. Site 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. Mr. Michael DQnovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W .0. 6935-A-SC November 3, 2015 Page 52 I I Minimizing irrigation will lessen this potential. If areas of seepage develop, recommendations for minimizing this effect could be provided upon request. Erosion Control Onsite earth materials have a moderate to high erosion potential due to their low plasticity and granular nature. Consideration should be given to providing hay bales, straw waddles, and silt fences for the temporary control of surface water, from a geotechnical viewpoint. Landscape Maintenance Only the amount of irrigation necessary to sustain plant life should be provided. Over-watering the landscape areas will adversely affect proposed site improvements. We would recommend that any proposed open-bottom planters adjacent to proposed structures be eliminated for a minimum distance of 10 feet. As an alternative, closed-bottom type planters could be utilized. An outlet placed in the bottom of the planter, could be installed to direct drainage away from structures or any exterior concrete flatwork. If planters are constructed adjacent to structures, the sides and bottom of the planter should be provided with a moisture barrier to prevent penetration of irrigation water into the subgrade. Provisions should be made to drain the excess irrigation water from the planters without saturating the subgrade below or adjacent to the planters. Graded slope areas should be planted with drought resistant vegetation. Consideration should be given to the type of vegetation chosen and their potential effect upon surface improvements (i.e., some trees will have an effect on concrete flatwork with their extensive root systems). From a geotechnical standpotnt leaching is not recommended for establishing landscaping. If the surface soils are processed for the purpose of adding amendments, they should be recompacted to 90 percent minimum relative compaction. Gutters and Downspouts As previously discussed in the drainage section, the installation of gutters and downspouts should be considered to collect roof water that may otherwise infiltrate the soils adjacent to the structures. If utilized, the downspouts should be drained into PVC collector pipes or other non-erosive devices (e.g., paved swales or ditches; below grade, solid tight-lined PVC pipes; etc.), that will carry the water away from the building, to an appropriate outlet, in accordance with the recommendations of the design civil engineer. Downspouts and gutters are not a requirement; however, from a geotechnical viewpoint, provided that positive drainage is incorporated into project design (as discussed previously). Subsurface and Surface Water Subsurface and surface water are not anticipated to affect site development, provided that the recommendations contained in this report are incorporated into final design and construction and that prudent surface and subsurface drainage practices are incorporated into the construction plans. Perched groundwater conditions along zones of contrasting permeabilities may not be precluded from occurring in the future due to site irrigation, poor Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 53 ., I drainage conditions, or damaged utilities, and should be anticipated. Should perched groundwater conditions develop, this office could assess the affected area(s) and provide the appropriate recommendations to mitigate the observed groundwater conditions. Groundwater conditions may change with the introduction of irrigation, rainfall, or other factors. Site Improvements If in the future, any additional improvements (e.g., pools, spas, etc.) are planned for the site, recommendations concerning the geological or geotechnical aspects of design and construction of said improvements could be provided upon request. Pools and/or spas should not be constructed without specific design and construction recommendations from GSI, and this construction recommendation should be provided to all interested/affected parties. This office should be notified in advance of any fill placement, grading of the site, or trench backfilling after rough grading has been completed. This includes any grading, utility trench and retaining wall backfills, flatwork, etc. Tile Flooring Tile flooring can crack, reflecting cracks in the concrete slab below the tile, although small cracks in a conventional slab may not be significant. Therefore, the designer should consider additional steel reinforcement for concrete slabs-on-grade where tile will be placed. The tile installer should consider installation methods that reduce possible cracking of the tile such as slipsheets. Slipsheets or a vinyl crack isolation membrane (approved by the Tile Council of America/Ceramic Tile Institute) are recommended between tile and concrete slabs on grade. Additional Grading This office should be notified in advance of any fill placement, supplemental regrading of the site, or trench backfilling after rough grading has been completed. This includes completion of grading in the street, driveway approaches, driveways, parking areas, and utility trench and retaining wall backfills. Footing Trench Excavation All footing excavations should be observed by a representative of this firm subsequent to trenching and prior to concrete form and reinforcement placement. The purpose of the observations is to evaluate that the excavations have been made into the recommended bearing material and to the minimum widths and depths recommended for construction. If loose or compressible materials are exposed within the footing excavation, a deeper footing or removal and recompaction of the subgrade materials would be recommended at that time. Footing trench spoil and any excess soils generated from utility trench excavations should be compacted to a minimum relative compaction of 90 percent, if not removed from the site. Mr.Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 54 4111 Trenching/Temporary Construction Backcuts Considering the nature of the onsite earth materials, it should be anticipated that caving or sloughing could be a factor in subsurface excavations and trenching. Shoring or excavating the trench walls/backcuts at the angle of repose (typically 25 to 45 degrees [except as specifically superceded within the text of this report]), should be anticipated. Recommendations for temporary slope construction are provided in a previous section of this report. All excavations should be observed by an engineering geologist or soil engineer from GSI, prior to workers entering the excavation or trench, and minimally conform to CAL-OSHA, state, and local safety codes. Should adverse conditions exist, appropriate recommendations would be offered at that time. The above recommendations should be provided to any contractors and/or subcontractors, or interested/affected parties, etc., that may perform such work. Utility Trench Backfill 1. All underground 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 (ASTM D 1557). As an alternative for shallow (12-inch to 18-inch) under-slab trenches, sand having a sand equivalent value of 30 or greater may be utilized and jetted or flooded into place, provided this method is acceptable to the controlling agency. Observation, probing and testing should be provided to evaluate the desired results. 2. Exterior trenches adjacent to, and within areas extending below a 1 :1 plane projected from the outside bottom edge of the footing, and all trenches beneath hardscape features and in slopes, should be compacted to at least 90 percent of the laboratory standard. Sand backfill, unless excavated from the trench, should not be used in these backfill areas. Compaction testing and observations, along with probing, should be accomplished to evaluate the desired results. 3. All trench excavations should conform to CAL-OSHA, state, and local safety codes. 4. Utilities crossing grade beams, perimeter beams, or footings should either pass below the footing or grade beam utilizing a hardened collar or foam spacer, or pass through the footing or grade beam in accordance with the recommendations of the structural engineer. SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING We recommend that observation and/or testing be performed by GSI at each of the following construction stages: • During grading/recertification. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 55 u I J J ~ :l • • • • • • • • • • During shoring installation and excavation . During placement of subdrains 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, pavement, 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, underground utility line trenches, and retaining wall backfill. During slope construction/repair . When any unusual soil conditions are encountered during any construction operations, subsequent to the issuance of this report. When any owner improvements, such as flatwork, spas, pools, walls, etc., are constructed, prior to construction. A report of geotechnical observation and testing should be provided at the conclusion of each of the above stages, in order to provide concise and clear documentation of site work, and/or to comply with code requirements. OTHER DESIGN PROFESSIONALS/CONSULTANTS The design civil engineer, structural engineer, post-tension designer, architect, landscape architect, wall designer, etc., should review the recommendations provided herein, incorporate those recommendations into all their respective plans, and by explicit reference, make this report part of their project plans. This report presents minimum design criteria for the design of slabs, foundations and other elements possibly applicable to the project. These criteria should not be considered as substitutes for actual designs by the structural engineer/designer. Please note that the recommendations contained herein are not intended to preclude the transmission of water or vapor through the slab or foundation. The structural engineer/foundation and/or slab designer should provide recommendations to not allow water or vapor to enter into the structure so as to cause damage to another building component, or so as to limit the installation of the type of flooring materials typically used for the particular application. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 56 - J J jl ' II f !I I I I I J The structural engineer/designer should analyze actual soil-structure interaction and consider, as needed, bearing, expansive soil influence, and strength, stiffness and deflections in the various slab, foundation, and other elements in order to develop appropriate, design-specific details. As conditions dictate, it is possible that other influences will also have to be considered. The structural engineer/designer should consider all applicable codes and authoritative sources where needed. If analyses by the structural engineer/designer result in less critical details than are provided herein as minimums, the minimums presented herein should be adopted. It is considered likely that some, more restrictive details will be required. If the structural engineer/designer has any questions or requires further assistance, they should not hesitate to call or otherwise transmit their requests to GSI. In order to mitigate potential distress, the foundation and/or improvement's designer should confirm to GSI and the governing agency, in writing, that the proposed foundations and/or improvements can tolerate the amount of differential settlement and/or expansion characteristics and other design criteria specified herein. PLAN REVIEW· Final project plans (grading, precise grading, foundation, retaining wall, landscaping, etc.), should be reviewed by this office prior to construction, so that construction is in accordance with the conclusions and recommendations of this report. Based on our review, supplemental recommendations and/or further geotechnical studies may be warranted. LIMITATIONS The materials encountered on the project site and utilized for our analysis are believed representative of the area; however, soil and bedrock materials vary in character between excavations and natural outcrops or conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors. Inasmuch as our study is based upon our review and engineering analyses and laboratory data, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty, either express or implied, is given. Standards of practice are subject to change with time. GSI assumes no responsibility or liability for work or testing performed by others, or their inaction; or work performed when GSI is not requested to be onsite, to evaluate if our recommendations have been properly implemented. Use of this report constitutes an agreement and consent by the user to all the limitations outlined above, notwithstanding any other agreements that may be in place. In addition, this report may be subject to review by the controlling authorities. Thus, this report brings to completion our scope of services for this portion of the project. All samples will be disposed of after 30 days, unless specifically requested by the client, in writing. Mr. Michael Donovan 2646 State Street, Carlsbad File:e:\wp12\6900\6935a.gef GeoSoils, Inc. W.O. 6935-A-SC November 3, 2015 Page 57 - ·------------·-----.. ---·-----------------~ 1-w w ex: l-oo l/J' I . I • I . I . I I "· I .. I, .. I llJ I so· 1---+-w"'-""-""""-• .. .. I • .. I I .. .. I I .. " I I GS/ LEGEND CARLSBAD CT- SHEET 2 OF 4 SHEETS I,~~ / ~ .,....-! ~ a • 'l:; / ~ ,;,; z d!! ~ ALL LOCATIONS ARE APPROXIMATE This document or efile is not a part of the Construction Documents and should not be relied upon as being an accurate depiction of design. Qop -QUATERNARY OLD PARALIC DEPOS/TSlAN '891· Tsa B-3 s TD=31 ~· TERTIARY SANTIAGO FORMATION, CIRC ---GEOTECHNICAL MAP Plate 1 W.O. 6935-A-SC DATE: 11/15 SCALE: 1" = 20' • .. J APPENDIX A REFERENCES ,1111 .... ... ''" GeoSoUs, Inc. 'II •• .... J J I J la ii ,. IC C ""'" ... ... APPENDIX A REFERENCES American Concrete Institute (ACI) Committee 318, 2011, Building code requirements for structural concrete (ACI 318-11) and commentary, dated August. ACI Committee 302, 2004, Guide for concrete floor and slab construction, ACI 302.1 R-04, dated June. Allen, V., Connerton, A., and Carlson, C., 2011, Introduction to Infiltration Best Management Practices (BMP), Contech Construction Products, Inc., Professional Development Series, dated December. American Society for Testing and Materials (ASTM), 2003, Standard test method for infiltration rate of soils in field using double-ring infiltrometer, Designation D 3385-03, dated August. __ , 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 specification for plastic water vapor retarders used in contact with soil or granular fill under concrete slabs, Designation: E 17 45-97 (Reapproved 2004). California Building Standards Commission, 2013, California Building Code, California Code of Regulations, Title 24, Part 2, Volume 2 of 2, Based on the 2012 International Building Code, 2013 California Historical Building Code, Title 24, Part 8; 2013 California Existing Building Code, Title 24, Part 10. Anderson, T.C., Reifurt, J.E., Reitz, P. and Licari, T., (1994), Temporary shoring support systems in an urban environment, American Society of Civil Engineers (ASCE) Annual Convention and Exposition, October 9 through 13. Blake, Thomas F., 2000a, EQFAULT, A computer program for the estimation of peak horizontal acceleration from 3-D fault sources; Windows 95/98 version. __ , 2000b, EQSEARCH, A computer program for the estimation of peak horizontal acceleration from California historical earthquake catalogs; Updated to July 2013, Windows 95/98 version. Bozorgnia, Y., Campbell K.W., and Niazi, M., 1999, Vertical ground motion: Characteristics, relationship with horizontal component, and building-code implications; Proceedings of the SMIP99 seminar on utilization of strong-motion data, September 15, Oakland, pp. 23-49. GeoSoils, Inc. "" J ~ . J ~ I,, ... Bryant, W.A., and Hart, E.W., 2007, Fault-rupture hazard zones in California, Alquist-Priolo earthquake fault zoning act with index to earthquake fault zones maps; California Geological Survey, Special Publication 42, interim revision. California Building Standards Commission, 2013, California Building Code, California Code of Regulations, Title 24, Part 2, Volume 2 of 2, Based on the 2012 International Building Code, 2013 California Historical Building Code, Title 24, Part 8; 2013 California Existing Building Code, Title 24, Part 10. California Department of Conservation, California Geological Survey (CGS), 2008, Guidelines for evaluating and mitigating seismic hazards in California: California Geological Survey Special Publication 117 A (revised 2008), 102 p. California Department of Water Resources, 1993, Division of Safety of Dams, Guidelines for the design and construction of small embankments dams, reprinted January. California Emergency Management Agency, California Geological Survey, and University of Southern California, 2009, Tsunami inundation map for emergency planning, San Luis Rey, 7.5-minute topographic quadrangle, San Diego County, California, · 1 :24,000-scale, dated June 1. California Stormwater Quality Association (CASQA), 2003, Stormwater best management practice handbook, new development and redevelopment, dated January. Cao, T., Bryant, W.A., Rowshandel, 8., Branum, D., and Wills, C.J., 2003, The revised 2002 California probabilistic seismic hazard maps, dated June, http://www.conservation.ca.gov/cgs/rghm/psha/fault_parameters/pdf/Documents /2002_CA_Hazard_Maps.pdf ' Coduto, D.P., 1999, Geotechnical engineering: principles and practices. County of San Diego, Department of Planning and Land Use, 2007, Low impact development (LID) handbook, stormwater management strategies, dated December 31. Hydrologic Solutions, StormChamber™ installation brochure, pgs. 1 through 8, undated. Jennings, C.W., and Bryant, W.A., 2010, Fault activity map of California, scale 1 :750,000, California Geological Survey, Geologic Data Map No. 6. Kanare, H.M., 2005, Concrete floors and moisture, Engineering Bulletin 119, Portland Cement Association. Karnak Planning & Design, 2015, First floor & basement plan, sheet AS-1-0, 20-scale, printed in July . Mr. Michael Donovan File:wp12\6900\6935a.gef GeoSoils, Inc. Appendix A Page 2 • ... '"'II ,., .J Kennedy, M.P., and Tan, SS., 2007, Geologic map of the Oceanside 301 by 601 quadrangle, California, regional geologic map series, scale 1: 100,000, California Geologic Survey Map No. 2. __ , 2005, Geologic map of the Oceanside 30' by 60' quadrangle, California, regional map series, scale 1: 100,000, California Geologic Survey and United States Geological Survey, www.conservation.ca.gov/cgs/rghm/rgm/ preliminary _geologic _maps.html MAA Design Group, 2015, Architectural drawings for: 2646 State Street, File No. 10-111, dated March 2. NorCal Engineering, 2002, Updated geotechnical investigation, proposed "Village By The Sea" residential development located at 2700 Carlsbad Boulevam in the City of Carlsbad, California, Project No.: 8710-00, dated April 8. __ , 2000, Preliminary geotechnical investigation, proposed residential development located at 2700 Carlsbad Boulevard in the City of Carlsbad, California, Project No.: 8710-00, dated August 14. Norris, R.M. and Webb, R.W., 1990, Geology of California, second edition, John Wiley & Sons, Inc. Romanoff, M., 1957, Underground corrosion, originally issued April 1. Seed, 2005, Evaluation and mitigation of soil liquefaction hazard "evaluation of field data and procedures for evaluating the risk of triggering (or inception) of liquefaction," in Geotechnical earthquake engineering; short coufse, San Diego, California, April 8-9. Sowers and Sowers, 1979, Unified soil classification system (After U. S: Waterways Experiment Station and ASTM 02487-667) in Introductory Soil Mechanics, New York . State of California, 2015, Civil Code, Sections 895 et seq. State of California Department of Transportation, Division of Engineering Services, Materials Engineering, and Testing Services, Corrosion Technology Branch, 2003, Corrosion Guidelines, Version 1.0, dated September. Tan, S.S. and Giffen, D.G., 1995, Landslide hazards in the northern part of the San Diego metropolitan area, San Diego County, California, DMG open file report 95-04, landslide hazard identification map no. 35, relative landslide susceptibility and landslide distribution map, plate 35A, 1 :24,000 scale. Mr. Michael Donovan File:wp12\6900\6935a.gef GeoSoils, Inc. Appendix A Page 3 '"'' I: j• ,, ... Tan, S.S.and Kennedy, M.P., 1996, Geologic maps of the northwestern part of San Diego County, California, DMG Open-File Report 96-02. United States Geological Survey, 2014, U.S. Seismic design maps, earthquake hazards program, http://geohazards.usgs.gov/designmaps/us/application.php. Version 3.1.0, dated July. __ , 1997, San Luis Rey quadrangle, San Diego County, California, 7.5 minute series, 1 :24,000 scale. Weber, H.F., 1982, Geologic map of north-central coastal area of San Diego County, California, showing recent slope failures and pre-development landslides: California Department of Conservation, Division of Mines and Geology, OFR 82-12 LA. Mr. Michael Donovan File:wp12\6900\6935a.gef GeoSoils, Inc. Appendix A Page 4 J 1,• ! . ,... I ~ J J ;J APPENDIX B BORING LOGS GeoSoils, Inc. "'' , Ii.ti C ,,,.. .... '111111 J .. .. UNIFIED SOIL CLASSIFICATl<iN SYSTEM CONSISTENCY OR RELATIVE DENSITY Major Divisions Group Symbols Typical Names CRITERIA GW Well-graded gravels and gravel- sand mixtures, little or no fines Standard Penetration Test Q) C: !!1. 5) co Q) 0 C: ·0 ~~ Poorly graded gravels and Penetration g? t) ... Q) .Q st (!) GP gravel-sand mixtures, little or no Resistance N Relative Q) U>'-tici ·;;; a50asz fines (blows/ft) Density >E~ 0 ~l5$5 0 C\I (!)~ ... "O Silty gravels gravel-sand-silt 0-4 Very loose U) • o as ai -a; .c GM ::0 0 0 c: mixtures oz I() 0 "iii {a .t: en c: Loose "O 0 2! c5 3:: 4-10 ~ "O GC Clayey gravels, gravel-sand-clay "i~ -~ mixtures 10-30 Medium C? i 5l ... Well-graded sands and gravelly 30-50 Dense ca~ SW sands, little or no fines 00 0 Q) C: U) t) I() C: 5) as "O Very dense Q) C: > 50 C ~ ,g ·;;; -as as UC!) Poorly graded sands and ,5 u,lt'l~st SP !!! "C C: .:: 0 gravelly sands, little or no fines 0 ~ ~ Q) z ::!!: cn-f?u, SM Silty sands, sand-silt mixtures a> as ai ... 0 U) .g :5 8l 0 0 U) E :g_ C ·-C: Clayey sands, sand-clay ~ ~ u::: SC mixtures Inorganic silts, very fine sands, Standard Penetration Test ML rock flour, silty or clayey fine sands U) Q) ~ :!: 81 Unconfined > 0~.9! Inorganic clays of low to Penetration Compressive Q) ·;;; -g ~ 0 CL medium plasticity, gravelly clays, Resistance N Strength 0 as 5-* sandy clays, silty clays, lean 0 (blows/ft) Consistency (tons/ff) !!1. C\I !::i~ clays ~~ Cl) "O U) Organic silts and organic silty <2 Very Soft <0.25 Q) Q) OL clays of low plasticity C: U) ·e gi 2-4 Soft 0.25-.050 (!) a. Inorganic silts, micaceous or ' Q) Q) ... 4-8 Medium 0.50-1.00 if ~ U) s MH diatomaceous fine sands or silts, l5 ~~ LO elastic silts c3 ~ i 8-15 Stiff 1.00-2.00 '#-Inorganic clays of high plasticity, 0 -g~ :5 CH I() as ::, ... fat clays 15-30 Very Stiff 2.00-4.00 ~g! --Q) Cl) ... >30 Hard >4.00 Cl Organic clays of medium to high OH plasticity Highly Organic Soils PT Peat, mucic, and other highly organic soils 3" 3/4" #4 #10 #40 #200 U.S. Standard Sieve Unified Soil Gravel Sand Silt or Clay Classification Cobbles I I I coarse fine coarse medium fine MOISTURE CONDITIONS MATERIAL QUANTITY OTHER SYMBOLS Dry Absence of moisture: dusty, dry to the touch trace 0-5% C Core Sample Slightly Moist Below optimum moisture content for compaction few 5-10% s SPTSample Moist Near optimum moisture content little 10-25 % B Bulk Sample Very Moist Above optimum moisture content some 25-45% -Groundwater -Wet Visible free water; below water table Qp Pocket Penetrometer BASIC LOG FORMAT: Group name, Group symbol, (grain size), color, moisture, consistency or relative density. Addition~ments: odor, presence of roots, mica, gypsum, coarse grained particles, etc. EXAMPLE: Sand (SP), fine to medium grained, brown, moist, loose, trace silt, little fine gravel, few cobbles up to 4' in size, some hair roots and rootlets . File:Mgr: c;\SoilClassif.wpd PLATE B-1 I 3 ,:J I GeoSoils, Inc. PROJECT: DONOVAN 2646 State Street, Carlsbad Sample ti' :s .9: "C ~ ~ Q) E ~ !E. € ii >, 2 Cl) ~ I!! .t: .!/l iii Cl) ::, ~ a .,. "C ~ (.) ~ ·o Q) :i C: Cl) 0 [D ::, ai ::, 0 :l: ,,. .. ;• CL 30 106.6 18.0 5-~ 63 117.9 14.6 6 SC 7- 8-GW 9- 10 ~ 61 SP 108.3 17.6 11- 12~" 13- 14- 15-~ 50-5" 120.4 9.0 16 17- 18- 19- 20-~ 50-4" 123.3 8.3 21- 22- 23- 24- 25 SC 26- 27- 28- 29- 30-rnQ1 -.n..A1L• 31-™ 32- 33- 34- 2646 State Street, Carlsbad BORING LOG w.o. 6935-A-SC BORING B-1 SHEET_1_ OF_1_ DATE EXCAVATED 8-28-15 SAMPLE METHOD: Hollow Stem Auger Approx. Elevation: 39' MSL m Standard Penetration Test l ¥ Groundwater C: ~ Undisturbed, Ring Sample f\i Seepage 0 e ~ Description of Material cn· v" COLLUVIUM: \ ® O' SIL TY SAND. dark brown (10 YR) drv loose· few roots. r 86.2 OLD PARALIC DEPOSITS: @ 1%' SANDY CLAY, brown (10 YR), wet, stiff; porous. @ 5' SANDY CLAY, olive brown (2.5 Y), wet, very stiff. 96.1 ~ @6' CLAYEY SAND, dark grayish brown (2.5 Y), wet, dense. K) 'v @ 7% GRAVELLY SAND with CLAY, brown (10 YR), moist, o[J i)o I dense. .,() 88.4 SANTIAGO FORMATION: @ 1 O' SANDSTONE, brownish gray (2.5 Y), wet, dense; fine to medium grained. @ 12' Water seepage into hole (no volume). 64.2 @ 15' SANDSTONE, light gray (2.5 Y), moist, dense; fine to medium grained. 64.2 @ 20' SANDSTONE, light gray (2.5 Y), moist, dense; fine to medium grained. ~ @ 25' CLAYEY SANDSTONE, light olive brown (2.5 Y), moist to ~ wet, dense. ~ ~ @ 30' CLAYEY SANDSTONE, light olive brown (2.5 Y), wet, dense. r Total Depth = 30%' Groundwater Encountered @ 12' No Caving Encountered Backfilled 8-28-2015 GeoSoils, Inc. PLATE B-2 [ .,,.. ... "'"" ... '"' m l GeoSoils, lac. PROJECT: DONOVAN 2646 State Street, Carlsbad Sample 'o 0 .e, "'O ..c ~ ~ -.8 E ~ !E. .., >, 5 u. en "" I!! .s::. ~ us en C: :::, C. ... ~ u ::, 1ii "'O (I) '5 C: en ~ ·o Cl Ill ::, Ill ::, Cl :E SM 1- 2- 3-~ 43 4 CL 5-~ 28 110.0 13.7 6 ~(' 7-~ 39 SP 109.3 12.9 8- 9 GP 10- 11- 12 I~ ~ 67 SP 111.6 16.9 13- 14- 15-I 72 16- 17- 18- 19- 20- 21- 22- 23- 24- 25 ~ 50-6" SC 121.1 12.4 26- 27- 28- 29- 30-ffl 71 31- 32- 33- 34- 2646 State Street, Carlsbad BORING LOG w.o. 6935-A-SC BORING B-2 SHEET_1_ OF_1_ DATE EXCAVATED 8-28-15 SAMPLE METHOD: Hollow Stem Auger Approx. Elevation: 39' MSL m Standard Penetration Test -~ 'Sl Groundwater a, C: ~ Undisturbed, Ring Sample f\! Seepage 0 e i Description of Material en '---"' UNDOCUMENTED FILL: -./"' @ O' SIL TY SAND, dark brown (10 YR}, slightly moist, loose; ~ ..r concrete, brick debris . -./' v-: ·....r-· @ 3' No recovery, concrete debris. -./' ~ OLD PARALIC DEPOSITS: 72.1 @4' SANDY CLAY, dark brown (10 YR}, moist, very stiff. ;// I @ 5' SANDY CLAY, dark brown (10 YR), moist, very stiff; some fr 66.3 11 caliche. \ @ 6' CLAYEY SAND. liaht olive brown (2.5 Y). moist dense. I @ 6%' SAND, light brown (2.5 Y), wet, dense. @ 8' Becomes verv dark aravish brown (10 YR)· fine arained. -• • @ 9' COBBLES/GRAVELS and SAND, brown (10 YR), moist, • • • dense . • • • • @ 11' Becomes wet. • • 92.7 SANTIAGO FORMATION: @ 12' SANDSTONE, light olive brown (2.5 Y), saturated, dense; . groundwater seepage into boring. @ 13' Becomes light gray (2.5 Y), wet, dense. @ 15' SANDSTONE, light gray (2.5 Y}, wet, dense; medium grained . @ 20' As per 15'. 89.9 ~ @ 25' CLAYEY SANDSTONE, light olive gray (2.5 Y), moist, dense. ~ ~ @ 30' As per 25'. ~ Total Depth = 31 W Groundwater Encountered@ 12' No Caving Encountered Backfilled 8-28-2015 GeoSoils, lac. PLATE B-3 BORING LOG GeoSoils, lac. w.o. 6935-A-SC PROJECT: DONOVAN BORING B-3 SHEET_1_ OF_1_ 2646 State Street, Carlsbad DATE EXCAVATED 8-28-15 Sample SAMPLE METHOD: Hollow Stem Auger Approx. Elevation: 39' MSL 't3' m Standard Penetration Test 0 .e, l 2 Groundwater -0 .c ~ ~ Q) E 0 ~ ? -e >, -C: Undisturbed, Ring Sample f\4 Seepage ii Cl) ~ I!! 0 .a :Q % iii Cl) :::, e! .!!! :::> ~ ~ -0 ] u ~ .a Q) :i C: Cl) (II Description of Material 0 aJ :::> aJ :::> 0 ::if; Cl) SM ""' COLLUVIUM: 1-er .J"' @ O' SIL TY SAND, brown (10 YR}, dry, loose . 2 -/' CL OLD PARALIC DEPOSITS: 3-@2' SANDY CLAY, brown (10 YR}, moist to wet, stiff; porous. 4-@4' SANDY CLAY, dark brown (10 YR), moist, very stiff. 5 @4%' SANDY CLAY, olive brown (2.5 YR), moist to wet, very r 6-stiff. 7-Total Depth= 5' No Groundwater/Caving Encountered 8-Backfilled 8-28-2015 9-,.. .. I 10- •• 11- 12-,,,.. 13- 14- 15-.... 16- •• 17- 18-.... 19-•• 20- 21- 22- 23- 24- 25- 26- 27- 28- 29- 30- 31- 32- 33- 34- 2646 State Street, Carlsbad GeoSoils, lac. PLATE B-4 .... , rm •• APPENDIXC SEISMICITY DATA GeoSolls, Inc. ... ., J J I I I I I TEST.OUT *********************** * * * E Q F A U L T * * * * * version 3.00 * * *********************** DETERMINISTIC ESTIMATION OF PEAK ACCELERATION FROM DIGITIZED FAULTS JOB NUMBER: 6935 JOB NAME: Donovan CALCULATION NAME: Test Run Analysis FAULT-DATA-FILE NAME: C:\EQ\EQFAULT\CGSFLTE.DAT SITE COORDINATES: SITE LATITUDE: 33.1634 SITE LONGITUDE: 117.3514 SEARCH RADIUS: 62 .4 mi DATE: 11-03-2015 ATTENUATION RELATION: 12) Bozorgnia Campbell Niazi (1999) Hor.-soft Rock-cor. UNCERTAINTY (M=Median, S=Sigma): S Number of Sigmas: 1.0 DISTANCE MEASURE: cdist SCOND: 1 Basement Depth: .01 km Campbell SSR: 1 Campbell SHR: 0 COMPUTE PE~K HORIZONTAL ACCELERATION FAULT-DATA FILE USED: C:\EQ\EQFAULT\CGSFLTE.DAT MINIMUM DEPTH VALUE (km): 3.0 Page 1 W.O. 6935-A-SC PLATE C-1 ... .... •• .... J l l .! J·· / . I Page 1 TEST.OUT EQFAULT SUMMARY DETERMINISTIC SITE PARAMETERS I !ESTIMATED MAX. EARTHQUAKE EVENT I APPROXIMATE 1------------------------------ABBREVIATED I DISTANCE I MAXIMUM PEAK !EST. SITE FAULT NAME I mi (km) !EARTHQUAKE SITE !INTENSITY I I MAG.(Mw) ACCEL. g IMOD.MERC. ================================l==============I========== ==========!========= NEWPORT-INGLEWOOD (Offshore) I 4.9( 7.9)1 7.1 0.610 I X ROSE CANYON I 5.3( 8.6)1 7.2 0.605 I x CORONADO BANK I 20.9( 33.7)1 7.6 0.271 I IX ELSINORE (TEMECULA) 24.2( 39.0)1 6.8 0.137 I VIII ELSINORE (JULIAN) . 24.6( 39.6)1 7.1 0.165 I VIII ELSINORE (GLEN IVY) 33.2( 53.4) 6.8 0.099 I VII SAN JOAQUIN HILLS 34.5( 55.6) 6.6 0.118 I VII PALOS VERDES 35.0( 56.4) 7.3 0.132 VIII EARTHQUAKE VALLEY 44.6( 71.8) 6.5 0.059 VI NEWPORT-INGLEWOOD CL.A.Basin) 45.2( 72.7) 7.1 0.088 VII SAN JACINTO-ANZA 46.7( 75.2) 7.2 0.092 VII CHINO-CENTRAL AVE. (Elsinore) 47.0( 75.7) 6.7 0.091 VII SAN JACINTO-SAN JACINTO VALLEY 47.2( 75.9) 6.9 0.074 VII WHITTIER 50.9( 81.9) 6.8 0.063 VI SAN JACINTO-COYOTE CREEK 52.9( 85.1) 6.6 0.053 VI ELSINORE (COYOTE MOUNTAIN) 58.8( 94.7) 6.8 0.054 VI SAN JACINTO-SAN BERNARDINO 59.4( 95.6) 6.7 0.050 VI PUENTE HILLS BLIND THRUST 60.7( 97.7) 7.1 0.092 VII ******************************************************************************* -END OF SEARCH-18 FAULTS FOUND WITHIN THE SPECIFIED SEARCH RADIUS. THE NEWPORT-INGLEWOOD (Offshore) FAULT IS CLOSEST TO THE SITE . IT IS ABOUT 4.9 MILES (7.9 km) AWAY . LARGEST MAXIMUM-EARTHQUAKE SITE ACCELERATION: 0.6096 g Page 2 W.O. 6935-A-SC PLATE C-2 """ . I I I I I I CALIFORNIA FAULT MAP Donovan 1000 900 800 700 600 500 400 300 200 100 0 -100+-'-'-._._-+-'-........... _,__ ................... ~~ ........ ..._ .......... ~~ ......... _._ ........................... __ ._._ ......... __._._._.___.. .......... ~ -400 -300 -200 -100 0 100 200 300 400 500 600 W.O. 6935-A-SC PLATE C-3 •• C: 0 ·-15 ~ Q) -Q) (.) (.) <( MAXIMUM EARTHQUAKES Donovan 1 .1 .01 .001 .1 1 10 Distance (mi) X W.O. 6935-A-SC PLATE C-4 J . ., I .J '~ ;J '.I 1• ,~ I ; ' I.. '""~ .. "'" .. .. : .. J J l I~ I• EARTHQUAKE MAGNITUDES & DISTANCES Donovan 7.6 7.5 7.4 7.3 -7.2 ~ .._ 7.1 Q) "C :::J 7.0 +-' ·-C 0) ro 6.9 ~ 6.8 6.7 6.6 6.5 .1 • • 1 10 Distance (mi) • • • ••• • .... •• • • • W.O. 6935-A-SC PLATEC-5 J I , I . I ·--·····--· ···-··•······----------------------- JOB NUMBER: 6935 TEST.OUT ************************* * * * * * * E Q S E A R C H version 3.00 * * * * ************************* ESTIMATION OF PEAK ACCELERATION FROM CALIFORNIA EARTHQUAKE CATALOGS DATE: 11-03-2015 JOB NAME: Donovan EARTHQUAKE-CATALOG-FILE NAME: ALLQUAKE.DAT MAGNITUDE RANGE: MINIMUM MAGNITUDE: 5.00 MAXIMUM MAGNITUDE: 9.00 SITE COORDINATES: SITE LATITUDE: 33.1634 SITE LONGITUDE: 117.3515 SEARCH DATES: START DATE: 1800 END DATE: 2015 SEARCH RADIUS: 62.4 mi 100.4 km ATTENUATION RELATION: 12) Bozorgnia Campbell Niazi (1999) Hor.-soft Rock-Cor. UNCERTAINTY (M=Median, S=Sigma): s Number of Sigmas: 1.0 ASSUMED SOURCE TYPE: 55 [SS=Strike-slip, DS=Reverse-slip, BT=Blind-thrust] SCOND: 0 Depth Source: A Basement Depth: .01 km Campbell SSR: 1 Campbell SHR: 0 COMPUTE PEAK HORIZONTAL ACCELERATION MINIMUM DEPTH VALUE (km): 3.0 Page 1 W.O. 6935-A-SC PLATE C-6 .. ..•. .... ~ J , ii .. ! '"1111 i 1illl I TEST.OUT EARTHQUAKE SEARCH RESULTS Page 1 I I I TIME I I I SITE ISITEI APPROX. FILEI LAT. I LONG. I DATE I (UTC) IDEPTHIQUAKEI ACC. I MM I DISTANCE CODEI NORTH I WEST I I HM Seel (km)I MAG.I g !INT.I mi [km] ----+-------+--------+----------+--------+-----+-----+-------+----+------------DMG 33.0000 117.3000111/22/1800 2130 0.0 0.01 6.501 0.233 I IX MGI 33.0000 117.0000109/21/1856 730 0.0 0.0 5.001 0.046 I VI MGI 32.8000 117.1000105/25/1803 0 0 o.o 0.0 5.001 0.037 I v PAS 32.9710 117.8700 07/13/1986 1347 8.2 6.0 5.301 0.039 I v DMG 32.7000 117.2000 05/27/1862 20 0 0.0 0.0 5.901 0.055 VI T-A 32.6700 117.1700 12/00/1856 0 0 0.0 0.0 5.001 0.030 V T-A 32.6700 117.1700 10/21/1862 0 0 0.0 0.0 5.001 0.030 V T-A 32.6700 117.1700 05/24/1865 0 0 0.0 0.0 5.001 0.030 V DMG 33.7000 117.4000 05/15/1910 1547 0.0 0.0 6.001 0.052 VI DMG 33.7000 117.4000 04/11/1910 757 0.0 0.0 5.001 0.029 V DMG 33.7000 117.4000 05/13/1910 620 0.0 0.0 5.001 0.029 V DMG 33.2000 116.7000 01/01/1920 235 0.0 0.0 5.00 0.028 V DMG 33.6990 117.5110 05/31/19381 83455.4 10.0 5.50 0.037 V DMG 32.8000 116.8000 10/23/1894 23 3 0.0 0.0 5.70 0.039 V MGI 33.2000 116.6000 10/12/1920 1748 0.0 0.0 5.30 0.029 V DMG 33.7100 116.9250 09/23/1963 144152.6 16.5 5.00 0.023 IV DMG 33.7500 117.0000 04/21/1918 223225.0 0.0 6.80 0.072 VI DMG 33.7500 117.0000 06/06/1918 2232 0.0 0.0 5.00 0.023 IV DMG 33.5750 117.9830 03/11/1933 518 4.0 0.0 5.20 0.026 V MGI 33.8000 117.6000 04/22/1918 2115 0.0 0.0 5.00 0.023 IV DMG 33.6170 117.9670 03/11/1933 154 7.8 0.0 6.30 0.049 VI DMG 33.8000 117.0000 12/25/1899 1225 0.0 0.0 6.40 0.051 VI DMG 33.6170 118.0170 03/14/1933 19 150.0 0.0 5.10 0.022 IV GSP 33.5290 116.5720 06/12/2005 154146.5 14.0 5.20 0.023 IV DMG 33.9000 117.2000 12/19/1880 0 0 0.0 0.0 6.00 0.037 V GSG 33.4200 116.4890 07/07/2010 235333.5 14.0 5.50 0.026 V PAS 33.5010 116.5130 02/25/19801104738.5 13.6 5.50 0.026 V GSP 33.5080 116.5140 10/31/2001 075616.6 15.0 5.10 0.021 IV DMG 33.6830 118.0500 03/11/1933 658 3.0 0.0 5.50 0.026 V DMG 33.0000 116.4330 06/04/1940 1035 8.3 0.0 5.10 0.020 IV DMG 33.5000 116.5000 09/30/1916 211 0.0 0.0 5.00 0.019 IV DMG 33.7000 118.0670 03/11/1933 85457.0 0.0 5.10 0.020 IV DMG 133.7000 118.0670103/11/1933 51022.0 0.0 5.10 0.020 IV DMG 134.0000 117.2500107/23/1923 73026.0 0.0 6.25 0.038 V MGI 134.0000 117.5000112/16/1858 10 0 0.0 0.0 7.00 0.063 VI DMG 133.7500 118.0830103/11/1933 910 0.0 0.0 5.10 0.019 IV DMG 133.7500 118.0830103/11/1933 323 0.0 0.0 5.00 0.018 IV DMG 133.7500 118.0830103/11/1933 230 0.0 0.0 5.10 0.019 IV DMG 133.7500 118.0830103/11/1933 2 9 0.0 0.0 5.00 0.018 IV DMG 133.7500 118.0830103/13/1933 131828.0 0.0 5.30 0.021 IV DMG 133.3430 116.3460104/28/1969 232042.9 20.0 5.80 0.028 V GSG 133.9530 117.7610107/29/2008 184215.7 14.0 5.30 0.021 IV DMG 133.9500 116.8500109/28/1946 719 9.0 0.0 5.00 0.017 IV Page 2 11. 7( 18.8) 23.3( 37.4) 29.0( 46.7) 32.8( 52.8) 33.2( 53.4) 35.6( 57.4). 35.6( 57.4) 35.6( 57.4) 37.2( 59.8) 37.2( 59.8) 37.2( 59.8) 37. 7( 60. 7) 38.1( 61.3) 40.6( 65.4) 43.5( 70.0) 45.0( 72.5) 45.3( 72.9) 45.3( 72.9) 46.2( 74.3) 46.2( 74.4) 47.3( 76.2) 48.4( 77.9) 49. 5( 79. 7) 51.6( 83.0) 51.6( 83.0) 52.8( 85.0) 53.7( 86.4) 53.8( 86.7) 53.9( 86.8) 54.3( 87.4) 54.3( 87.4) 55.4( 89.2) 55.4( 89.2) 58.1( 93.4) 58.4( 94.0) 58.4( 94.0) 58.4( 94.0) 58.4( 94.0) 58.4( 94.0) 58.4( 94.0) 59.4( 95.5) 59.4( 95.6) 61. 5( 99.0) W.O. 6935-A-SC PLATE C-7 '"' TEST.OUT DMG l33.7830l118.1330ll0/02/1933I 91017.61 0.01 5.401 0.021 I IV I 62.1( 99.9) GSG 133.93251117.9172103/29/20141040942.31 4.81 5.101 0.018 I IV I 62.3(100.2) ~ ******************************************************************************* , J ..... IH J J -END OF SEARCH-45 EARTHQUAKES FOUND WITHIN THE SPECIFIED SEARCH AREA. TIME PERIOD OF SEARCH: 1800 TO 2015 LENGTH OF SEARCH TIME: 216 years THE EARTHQUAKE CLOSEST TO THE SITE IS ABOUT 11.7 MILES (18.8 km) AWAY. LARGEST EARTHQUAKE MAGNITUDE FOUND IN THE SEARCH RADIUS: 7.0 LARGEST EARTHQUAKE SITE ACCELERATION FROM THIS SEARCH: 0.233 g COEFFICIENTS FOR GUTENBERG & RICHTER RECURRENCE RELATION: a-value= 1.051 b-value= 0.395 beta-value= 0.911 TABLE OF MAGNITUDES AND EXCEEDANCES: Earthquake I Number of Times I Cumulative Magnitude I Exceeded I No. I Year ----------'+-----------------+------------4.0 I 45 I 0.20833 4.5 I 45 I 0.20833 5.0 I 45 I 0.20833 5 . 5 I 15 I o. 06944 6.0 I 8 I 0.03704 6. 5 I 3 I 0.01389 7.0 I 1 I 0.00463 Page 3 W.O. 6935-A-SC PLATE C-8 i • ; I J l I EARTHQUAKE EPICENTER MAP Donovan 1000 900 800 700 600 500 400 300 200 LEGEND M=4 M=5 100 M =6 M=7 • 0 M=8 -100~~-'-,e-'--~"""-t-~~---~~r-~-r~~--~~---~----~~....._~----i -400 -300 -200 -100 0 100 200 300 400 500 600 W.O. 6935-A-SC PLATE C-9 .. ,~ .... ;oil , ... ... 1'1111 11111! ~ .. "' ill I,.. m I Q) 1 >-" -• -z -(/) C -C Q) > w -,. 0 l I,.. Ill Q) .0 "'9! E :::J 1111 z Q) > ""'' ~ .. , :::J E 'fUII E :::J WI () ~,, ... .. "" .. .. ) .. ''"I ~ .., J .... d "-----------------------------,c EARTHQUAKE RECURRENCE CURVE 100 10 1 .1 .01 .001 Donovan ""'" ......... ~~ .. •• ' "- -.... .. ........... .............. 0 ' I t I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 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 (M) W.O. 6935-A-SC PLATE C-10 _., ,,., coll '"'II .. ""' • "" .. f [ 2 C - i C l ,., } I ... 1 l i '"" i i I _, J l "" / ' ill } i D I ~ I D J J J -z -en -C Q) > w -0 I-Q) .0 E ::l z Q) > ~ ::l E ::l () Number of Earthquakes (N) Above Magnitude (M) 40 20 10 8 6 4 2 Donovan 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 (M) W.O. 6935-A-SC PLATE C-11 ... , ' .. I I 11111 i ill Ir 1ii1 t ,: ""·· • ; "'" ., i lilt I j ""' 1 i t iu l .... 1 • - ' I :J I ·'11 J:: ,, A .. ~-· -·-·-·----------------.... APPENDIX D LABORATORY DATA GeoSoils, Inc. ... , J I g I I I ' 1 I J' I :• I 60 CL 50 ~ 40 Cl ~ / >-/ / I-/ B 30 / en / ~ / • a. / / / 20 / / / V / / / / / / / 10 V / / CL-...,L / ML I 0 I 0 20 40 Sample Depth/El. LL PL Pl Fines e B-1 1.5 41 15 26 GeoSoils, Inc. 57 41 Palmer Way f-Carlsbad, CA 92008 Telephone: (760) 438-3155 Fax: (760) 931-0915 / V / ,V / CH / / / / 1,/ V / / / / / / / V / v· MH 60 80 100 LIQUID LIMIT uses CLASSIFICATION A ITERBERG LIMITS' RESULTS Project: DONOVAN Number: 6935-A-SC Date: November 2015 Plate: D-1 , J ""' ..... •• ..... •• ,,.. J J l J 0.0 0.2 0.4 .___ ~ ~ 0.6 0.8 1.0 ~ 0 1.2 z ~ I-1.4 Cl) 1.6 1.8 2.0 2.2 a 2.4 2.6 100 Sample Depth/El. e B-2 5.0 Clayey Sand Stress at which water was added: 1000 psf Strain Difference: 0.41% ---- GeoSoils, Inc. t 57 41 Palmer Way Carlsbad, CA 92008 Telephone: (760) 438-3155 Fax: (760) 931-0915 "" I"'-"' "' I"'. t 4~ ~ \ ~ \. \ \ -i----\ r----r---..._ ~. \ ~ \ -------r----_ ~----------- 1,000 10,000 STRESS, psf Visual Classification yd MC MC H20 Initial Initial Final 0.1 14.6 17.1 1000 CONSOLIDATION TEST Project: DONOVAN Number: 6935-A-SC Date: November 2015 Plate: D -2 J J , .. •• ·11• .. l l • 1· jJ • D 4,000 3,000 'lii C. :I: I-C) /• z w 0:: ti; / 0:: 2,000 <( / w J: Cl) y ~ 1,000 V V • 0 0 1,000 2,000 3,000 4,000 NORMAL PRESSURE, psf Sample Depth/El. Range Classification Primary/Residual Sample Type yd MC% C + B-1 1.5 Primary Shear Remolded 113.2 12.5 239 25 B-1 1.5 Residual Shear Remolded 113.2 12.5 234 25 Reshear Shear Remolded Reshear Shear Remolded Note: Sample lnnundated Prior To Test GeoSoils, Inc. DIRECT SHEAR TEST • 57 41 Palmer Way Project: DONOVAN Carlsbad, CA 92008 Telephone: (760) 438-3155 Number: 6935-A-SC Fax: (760) 931-0915 Date: November 2015 Plate: D-3 ""' .... J • "' ~ D b C) ai :5 Cl) :::> ii C) .,; "' a, ID Cl) Sample Depth/El. Range Classification B-1 10.0 Clayey Sand B-1 10.0 Note: Sample lnnundated Prior To Test GeoSoils, Inc. 57 41 Palmer Way Carlsbad, CA 92008 Telephone: (760) 438-3155 Fax: (760) 931-0915 NORMAL PRESSURE, psf Primary/Residual Sample Type yd MC% C Primary Shear Undisturbed 108.7 17.6 98 Residual Shear Undisturbed 108.7 17.6 22 Reshear Shear Undisturbed Reshear Shear Undisturbed DIRECT SHEAR TEST Project: DONOVAN Number: 6935-A-SC Date: November 2015 Plate: D-4 cl> 41 35 :::>._ __________________________________________________________________________________ .. . ., ,.... •• J J J J J Cal Land Engineering, Inc . dba Quartech Consultant Geotechnical, Environmental, and Civil Engineering SUMMARY OF LABORATORY TEST DATA GeoSoils, Inc. 5741 Palmer Way, Suite D Carlsbad, CA 92010 W.O. 6935-A-SC Project Name: 2646 State Street, Carlsbad, CA Client: Donovan B-1 1.5'-3' B-2 15' QCI Project No.: 15-029-009c Date: September 17, 2015 Summarized by: KA 10 15 0.1410 0.0360 W.O. 6935-A-SC PLATE D-5 576 East Lambert Road, Brea, California 92821; Tel: 714-671-1050; Fax: 714-671-1090 ... I I D I I I ii !1 APPENDIX E GENERAL EARTHWORK AND GRADING GUIDELINES GeoSoils, Inc. '"" ,illlll •• """' . , ... - D 3 J l GENERAL EARTHWORK AND GRADING GUIDELINES General These guidelines present general procedures and requirements for earthwork and grading as shown on the approved grading plans, including preparation of areas to be filled, placement of fill, installation of subdratns, excavations, and appurtenant structures or flatwork. The recommendations contained in the geotechnical report are part of these earthwork and grading guidelines and would supercedethe provisions contained hereafter in the case of conflict. Evaluations performed by the consultant during the course of grading may result in new or revised recommendations which could supercede these guidelines or the recommendations contained in the geotechnical report. Generalized details follow this text. The contractor is responsible for the satisfactory completion of all earthwork in accordance with provisions of the project plans and specifications and latest adopted code. In the case of conflict, the most onerous provisions shall prevail. The project geotechnical engineer and engineering geologist (geotechnical consultant), and/or their representatives, should . provide observation and testing services, and geotechnical consultation during the duration of the project. EARTHWORK OBSERVATIONS AND TESTING Geotechnical Consultant Prior to the commencement of grading, a qualified geotechnical consultant (soil engineer and engineering geologist) should be employed for the purpose of ·observing earthwork procedures and testing the fills for general conformance with the recommendations of the geotechnical report(s), the approved grading plans, and applicable grading codes and ordinances . The geotechnical consultant should provide testing and observation so that an evaluation may be made that the work is being accomplished as specified. It is the responsibility of the contractor to assist the consultants and keep them apprised of anticipated work schedules and changes, so that they may schedule their personnel accordingly. All remedial removals, clean-outs, prepared ground to receive fill, key excavations, and subdrain installation should be observed and documented by the geotechnical consultant prior to placing any fill. It is the contractor's responsibility to notify the geotechnical consultant when such areas are ready for observation. Laboratory and Field Tests Maximum dry density tests to determine the degree of compaction should be performed in accordance with American Standard Testing Materials test method ASTM designation 0-1557. Random or representative field compaction tests should be performed in GeoSoils, Inc. 111 : J I ;~ , .. ~ c. I ..... .... 1111 ] . I accordance with test methods ASTM designation D-1556, D-2937 or D-2922, and D-3017, at intervals of approximately ±2 feet of fill height or approximately every .t.OOO cubic yards placed. These criteria would vary depending on the soil conditions and the size of the project. The location and frequency of testing would be at the discretion of the geotechnical consultant. Contractor•s Responsibility All clearing, site preparation, and earthwork performed on the project should be conducted by the contractor, with observation by a geotechnical consultant, and staged approval by the governing agencies, as applicable. It is the contractor's responsibility to prepare the ground surface to receive the fill, to the satisfaction of the geotechnical consultant, and to place, spread, moisture condition, mix, and compact the fill in accordance with the recommendations of the geotechnical consultant. The contractor should also remove all non-earth material considered unsatisfactory by the geotechnical consultant. Notwithstanding the services provided by the geotechnical consultant, it is the sole responsibility of the contractor to provide adequate equipment and methods to accomplish the earthwork in strict accordance with applicable grading guidelines, latest adopted 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 for the fill material, rate of placement, and climatic conditions. If, in the opinion of the geotechnical consultant, unsatisfactory conditions such as questionable weather, excessive oversized rock or deleterious material, insufficient support equipment, etc., are resulting in a quality of work that is not acceptable, the consultant will inform the contractor, and the contractor is expected to rectify the conditions, and if necessary, stop work until conditions are satisfactory. During construction, the contractor shall properly grade all surfaces to maintain good drainage and prevent ponding of water. The contractor shall take remedial measures to control surface water and to prevent erosion of graded areas until such time as permanent drainage and erosion control measures have been installed . SITE PREPARATION All major vegetation, including brush, trees, thick grasses, organic debris, and other deleterious material, should be removed and disposed of off-site. These removals must be concluded prior to placing fill. In-place existing fill, soil, alluvium, colluvium, or rock materials, as evaluated by the geotechnical consultant as being unsuitable, should be removed prior to any fill placement. Depending upon the soil conditions, these materials may be reused as compacted fills. Any materials incorporated as part of the compacted fills should be approved by the geotechnical consultant. Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septic tanks, wells, pipelines, or other structures not located prior to grading, are to be removed Mr. Michael Donovan File:e:\wp12\6900\6935a.gef GeoSoils, Inc. Appendix E Page 2 J J or treated in a manner recommended by the geotechnical consultant. Soft, dry, spongy, highly fractured, or otherwise unsuitable ground, extending to such a depth that surface processing cannot adequately improve the condition, should be overexcavated down to firm ground and approved by the geotechnical consultant before compaction and filling operations continue. Overexcavated and processed soils, which have been properly mixed and moisture conditioned, should be re-compacted to the minimum relative compaction as specified in these guidelines. Existing ground, which is determined to be satisfactory for support of the fills, should be scarified (ripped) to a minimum depth of 6 to 8 inches, or as directed by the geotechnical consultant. After the scarified ground is brought to optimum moisture content, or greater and mixed, the materials should be compacted as specified herein. If the scarified zone is greater than 6 to 8 inches in depth, it may be necessary to remove the excess and place the material in lifts restricted to about 6 to 8 inches in compacted thickness. Existing ground which is not satisfactory to support compacted fill should be overexcavated as required in the geotechnical report, or by the on-site geotechnical consultant. Scarification, disc harrowing, or other acceptable forms of mixing should continue until the soils are broken down and free of large lumps or clods, until the working surface is reasonably uniform and free from ruts, hollows, hummocks, mounds, or other uneven features, which would inhibit compaction as described previously. Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical [h:v]), the ground should be stepped or benched. The lowest bench, which will act as a key, should be a minimum of 15 feet wide and should be at least 2 feet deep into firm material, and approved by the geotechnical consultant. In fill-over-cut slope conditions, the recommended minimum width of the lowest bench or key is also 15 feet, with the key founded on firm material, as designated by the geotechnical consultant. As a general rule, unless specifically recommended otherwise by the geotechnical consultant, the minimum width of fill keys should be equal to % the height of the slope. Standard benching is generally 4 feet (minimumr ¥ertically, exposing firm, acceptable material. Benching may be used to remove unsuitable materials, although it is understood that the vertical height of the bench may exceed 4 feet. Pre-stripping may be considered for unsuitable materials in excess of 4 feet in thickness. All areas to receive fill, including processed areas, removal areas, and the toes of fill benches, should be observed and approved by the geotechnical consultant prior to placement of fill. Fills may then be properly placed and compacted until design grades (elevations) are attained. COMPACTED FILLS Any earth materials imported or excavated on the property may be utilized in the fill provided that each material has been evaluated to be suitable by the geotechnical Mr.Michael Donovan File:e:\wp12\6900\6935a.gef GeoSoils, Inc. Appendix E Page 3 ... .... ... .... ,,,,,. J .... j • consultant. These materials should be free of roots, tree branches, other organic matter, or other deleterious materials. All unsuitable materials should be removed from the fill as directed by the geotechnical consultant. Soils of poor gradation, undesirable expansion potential, or substandard strength characteristics may be designated by the consultant as unsuitable and may require blending with other soils to serve as a satisfactory fill material. Fitt materials derived from benching operations should be dispersed throughout the fill area and blended with other approved material. Benching operations should not result in the benched material being placed only within a single equipment width away from the fill/bedrock contact. Oversized materials defined as rock, or other irreducible materials, with a maximum dimension greater than 12 inches, should not be buried or placed in fills unless the location of materials and disposal methods are specifically approved by the geotechnical consultant. Oversized material should be taken offsite, or placed in accordance with recommendations of the geotechnical consultant in areas designated as suitable for rock disposal. GSI anticipates that soils to be utilized as fill material for the subject project may contain some rock. Appropriately, the need for rock disposal may be necessary during grading operations on the site. From a geotechnical standpoint, the depth of any rocks, rock fills, or rock blankets, should be a sufficient distance from finish grade. This depth is generally the same as any overexcavation due to cut-fill transitions in hard rock areas, and generally facilitates the excavation of structural footings and substructures. Should deeper excavations be proposed (i.e., deepened footings, utility trenching, swimming pools, spas, etc.), the developer may consider increasing the hold-down depth of any rocky fills to be placed, as appropriate. In addition, some agencies/jurisdictions mandate a specific hold-down depth for oversize materials placed in fills. The hold-down depth, and potential to encounter oversize rock, both within fills, and occurring in cut or natural areas, would need to be disclosed to all interested/affected parties. Once approved by the governing agency, the hold-down depth for oversized rock (i.e., greater than 12 inches) in fills on this project is provided as 1 O feet, unless specified differently in the text of this report. The governing agency may require that these materials need to be deeper, crushed, or reduced to less than 12 inches in maximum dimension, at their discretion. To facilitate future trenching, rock (or oversized material), should not be placed within the hold-down depth feetfrom finish grade, the rang~otfflt.Jndation excavations, future utilities, or underground construction unless specifically approved by the governing agency, the geotechnical consultant, and/or the developer's representative. If import material is required for grading, representative samples of the materials to be utilized as compacted fill should be analyzed in the laboratory by the geotechnical consultant to evaluate it's physical properties and suitability for use onsite. Such testing should be performed three (3) days prior to importation. If any material other than that previously tested is encountered during grading, an appropriate analysis of this material should be conducted by the geotechnical consultant as soon as possible. Mr. Michael Donovan File:e:\wp12\6900\6935a.gef GeoSoils, Inc. Appendix E Page 4 "'' al ""' .... , .... .... ·~• ... .... J l ,] I, i Iii Approved fill material should be placed in areas prepared to receive fill in near horizontal layers, that when compacted, should not exceed about 6 to 8 inches in thickness. The geotechnical consultant may approve thick lifts if testing indicates the grading procedures are such that adequate compaction is being achieved with lifts of greater thickness. Each layer should be spread evenly and blended to attain uniformity of material and moisture suitable for compaction. Fill layers at a moisture content less than optimum should be watered and mixed, and wet fill layers should be aerated by scarification, or should be blended with drier material. Moisture conditioning, blending, and mixing of the fill layer should continue until the fill materials have a uniform moisture content at, or above, optimum moisture. After each layer has been evenly spread, moisture conditioned, and mixed, it should be uniformly compacted to a minimum of 90 percent of the maximum density as evaluated by ASTM test designation D-1557, or as otherwise recommended by the geotechnical consultant. Compaction equipment should be adequately sized and should be specifically designed for soil compaction, or of proven reliability to efficiently achieve the specified degree of compaction. Where tests indicate that the density of any layer of fill, or portion thereof, is below the required relative compaction, or improper moisture is in evidence, the particular layer or portion shall be re-worked until the required density and/or moisture content has been attained. No additional fill shall be placed in an area until the last placed lift of fill has been tested and found to meet the density and moisture requirements, and is approved by the geotechnical consultant. In general, per the latest adopted version of the 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 subsequently trimming back to the design slope configuration. Testing shall be performed as the fill is elevated to evaluate compaction as the fill core is being developed. Special efforts may be necessary to attain the specified compaction in the fill slope zone. Final slope shaping should be performed by trimming and removing loose materials with appropriate equipment. A final evaluation of fill slope compaction should be based on observation and/or testing of the finished slope face. Where compacted fill slopes are designed steeper than 2:1 (h:v), prior approval from the governing agency, specific material types, a higher minimum relative compaction, special reinforcement, and special grading procedures will be recommended . If an alternative to over-building and cutting back the compacted fill slopes is selected, then special effort should be made to achieve the required compaction in the outer 1 O feet of each lift of fill by undertaking the following: 1. An extra piece of equipment consisting of a heavy, short-shanked sheepsfoot should be used to roll (horizontal) parallel to the slopes continuously as fill is placed. The sheepsfoot roller should also be used to roll perpendicular to the Mr. Michael Donovan File:e:\wp12\6900\6935a.gef GeoSoils, Inc. Appendix E Page 5 ,,,. . , .. . ,... .... <IH lllll '""' 2. 3 . 4. 5. slopes, and extend out over the slope to provide adequate compaction to the face of the slope. 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. 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. 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. Where testing indicates less than adequate compaction, the contractor will be responsible to rip, water, mix, and recompact the slope material as necessary to achieve compaction. Additional testing should be performed to evaluate compaction. SUBDRAIN INSTALLATION Subdrains should be installed in approved ground in accordance with the approximate alignment and details indicated by the geotechnical consultant. Subdrain locations or materials should not be changed or modified without approval of the geotechnical consultant. The geotechnical consultant may recommend and direct changes in subdrain line, grade, and drain material in the field, pending exposed conditions. The location of constructedsubdrains, especially the outlets, should be recorded/surveyed by the project civil engineer. Drainage at the subdrain outlets should be provided by the project civil engineer. EXCAVATIONS Excavations· and cut slopes should be examined during grading by the geotechnical consultant. If directed by the geotechnical consultant, further excavations or overexcavation and refilling of cut areas should be performed, and/or remedial grading of cut slopes should be performed. When fill-over-cut slopes are to be graded, unless otherwise approved, the cut portion of the slope should be observed by the geotechnical consultant prior to placement of materials for construction of the fill portion of the slope. The geotechnical consultant should observe all cut slopes, and should be notified by the contractor when excavation of cut slopes commence. Mr. Michael Donovan File:e:\wp12\6900\6935a.gef GeoSoils, Inc. Appendix E Page 6 ..... l ii., ,,.. ..... J l J 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 otherwise specified in geotechnical and geological report(s), no cut slopes should be excavated higher or steeper than that allowed by the ordinances of controlling governmental agencies. Additionally, short-term stability of temporary cut slopes is the contractor's responsibility. Erosion control and drainage devices should be designed by the project civil engineer and should be constructed in compliance with the ordinances of the controlling governmental agencies, and/or in accordance with the recommendations of the geotechnical consultant. COMPLETION Observation, testing, and consultation by the geotechnical consultant should be conducted during the grading operations in order to state an opinion that all cut and fill areas are graded in accordance with the approved project specifications. After completion of grading, and after the geotechnical consultant has finished observations of the work, final reports should be submitted, and may be subject to review by the controlling governmental agencies. No further excavation or filling should be undertaken without prior notification of the geotechnical consultant or approved plans. All finished cut and fill slopes should be protected from erosion and/or be planted in accordance with the project specifications and/or as recommended by a landscape architect. Such protection and/or planning should be undertaken as soon as practical after completion of grading . 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. Mr. Michael Donovan File:e:\wp12\6900\6935a.gef GeoSoils, Inc. Appendix E Page 7 ""' f .... •• . "" In an effort to minimize risks associated with geotechnical testing and observation, the following precautions are to be implemented for the safety of field personnel on grading and construction projects: Safety Meetings: GSI field personnel are directed to attend contractor's regularly scheduled and documented safety meetings. Safety Vests: Safety vests are provided for, and are to be worn by GSI personnel, at all times, when they are working in the field. Safety Flags: Two safety flags are provided to GSI field technicians; one is to be affixed to the vehicle when on site, the other is to be placed atop the spoil pile on all test pits. Flashing Lights: All vehicles stationary in the grading area shall use rotating or flashing amber beacons, or strobe lights, on the vehicle during all field testing. While operating a vehicle in the grading area, the emergency flasher on the vehicle shall be activated. In the event that the contractor's representative observes any of our personnel not following the above, we request that it be brought to the attention of our office. Test Pits Location, Orientation, and Clearance The technician is responsible for selecting test pit locations. A primary concern should be the technician's safety. Efforts will be made to coordinate locations with the grading contractor's authorized representative, and to select locations following or behind the established traffic pattern, preferably outside of current traffic. The contractor's authorized representative (supervisor, grade checker, dump man, operator, etc.) should direct excavation of the pit and safety during the test period. Of paramount concern should be the soil technician's safety, and obtaining enough tests to represent the fill. Test pits should be excavated so that the spoil pile is placed away from oncoming traffic, whenever possible. The technician's vehicle is to be placed next to the test pit, opposite the spoil pile. This necessitates the fill be maintained in a driveable condition . Alternatively, the contractor may wish to park a piece of equipment in front of the test holes, particularly in small fill areas or those with limited access. A zone of non-encroachment should be established for all test pits. No grading equipment should enter this zone during the testing procedure. The zone should extend approximately 50 feet outward from the center of the test pit. This zone is established for safety and to avoid excessive ground vibration, which typically decreases test results. 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. Mr. Michael Donovan File:e:\wp12\6900\6935a.gef GeoSoils, Inc. Appendix E Page 8 ,.. Ill, ,, ... " I I J I I J I l1 The technician is directed to withdraw from the active portion of the fill as soon as possible following testing. The technician's vehicle should be parked at the perimeter of the fill in a highly visible location, well away from the equipment traffic pattern. The contractor should inform our personnel of all changes to haul roads, cut and fill areas or other factors that may affect site access and site safety. In the event that the technician's safety is jeopardized or compromised as a result of the contractor's failure to comply with any of the above, the technician is required, by company policy, to immediately withdraw and notify his/her supervisor. The grading contractor's representative will be contacted in an effort to affect a solution. However, in the interim, no further testing will be performed until the situation is rectified. Any fill placed can be considered unacceptable and subject to reprocessing, recompaction, or removal. In the event that the soil technician does not comply with the above or other established safety guidelines, we request that the contractor bring this to the technician's attention and notify this office. Effective communication and coordination between the contractor's representative and the soil technician is strongly encouraged in order to implement the above safety plan. Trench and Vertical Excavation It is the contractor's responsibility to provide safe access into trenches where compaction testing is needed. Our personnel are directed not to enter any excavation or vertical cut which: 1) is 5 feet or deeper unless shored or laid back; 2) displays any evidence of instability, has any loose rock or other debris which could fall into the trench; or 3}displays any other evidence of any unsafe conditions regardless of depth. All trench excavations or vertical cuts in excess of 5 feet deep, which any person enters, should be shored or laid back. Trench access should be provided in accordance with Cal/OSHA and/or state and local standards. Our personnel are directed not to enter any trench by being lowered or "riding down" on the equipment. If the contractor fails to provide safe access to trenches for compaction testing, our company policy requires that the soil technician withdraw and notify his/her supervisor. The contractor's representative will be contacted in an effort to affect a solution. All backfill not tested due to safety concerns or other reasons could be subject to reprocessing and/or removal. If GSI personnel become aware of anyone working beneath an unsafe trench wall or vertical excavation, we have a legal obligation to put the contractor and owner/developer on notice to immediately correct the situation. If corrective steps are not taken, GSI then has an obligation to notify Cal/OSHA and/or the proper controlling authorities. Mr. Michael Donovan File:e:\wp12\6900\6935a.gef GeoSoils, Inc. Appendix E Page 9 ""' ,.. i .. ! f •• "'"' "" illfl TYPE A TYPE B Selection of alternate subdrain details, location, and extent of subdrains should be evaluated by the geotechnical consultant during grading. CANYON SUBDRAIN DETAIL Plate E-1 • .... '""' mt• .... "'" Iii. ..... .... ... 6-inch minimum A-1 Filter material: Minimum volume of 9 cubic feet per lineal foot of pipe. AL TEA MATERIAL Perforated pipe: 6-inch-diameter ABS or PVC pipe or approved substitute with minimum 8 perforations °'4-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 a-inch-diameter pipe (ASTM D-3034, SDR-35, or ASTM D-1785, Schd. 40). Sieve Size 1 inch %inch % inch No.4 No.a No.30 No.SO No.200 Percent Passing 100 90-100 40-100 25-40 18-33 5-15 0-7 0-3 AL TEANATE 1: PERFORATED PIPE AND RL TEA MATERIAL \ .... ----6-inch minimum _) \ "'I I I \ I !'-~-~nch --: ~6-nch nmun f mlllmum --- Filter fabric A-2 Gravel Material: 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. I I ALTERNATE 2: PERFORATED PIPE, GRAVEL, AND ALTER FABRIC CANYON SUBDRAIN ALTERNATE DETAILS Plate E-2 &.a -..,. ... L.I R:.·. ,II ...... L..I & ,J I J I. J Original ground surface to be restored with compacted fill I 1- Back-cut varies. For deep removals, backcut should be made no steeper than 1=1 (H:V), or flatter as necessary for safety considerations. 2D a:"'"I I I .. 1 / ,---, l"-''1 &I L,;J ll j -· ... ~--Toe of slope as shown on grading plan l j /.<?..': .: ::::. ·····,-. c ·. ·· ... = ··: ·· · . .-: -Compact~d. Fill· = ·, · · ~.· .. :·:·· .. ·."' ·,·· .,. '·.::---: : ........ , .. _::: ...... : .. ·.· .. . .. ··. ! ~~ / I \__Original ground surface . .;'. ~ / D • Anticipated removal of l.llSUitable material . $/ / {depth per geotechnical engMer) ~ / 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. a419Jae. FILL SLOPE TOEING OUT ON FLAT ALLUVIATED CANYON DETAIL Plate E-3 ~ ..... &.J&_.llill .. ii a I Iii i . ... II I • • ! 1 Y'l ' 1 I. J &; 4 lie i --.... i j ! Proposed grade~ ---- r----Previously placed, temporary compacted fill for drainage only ------ Proposed additional compacted fill Existing com . +{!@-±'DZPW0~<~ pacted iii 9<,__ s.;-· · · · . · · 7 ·• · Unsuil' bf' · • · · · · · " · · -~ i ( > : < • a _e ~ieri~I (t!> be rem · ·•· • .-. • ... ·. · :7-"\\:'.<Y,\ · · · .. oved) 0.\0"~\\~~)\Y(\0»?'~\);'.\\\<('~)"0-<:\ ;<::0fa~ y\\'(,,< To be remo Bedrock or a add~lonal cied before placing native materiaFoved mpacted fill c418Jae. REMOVAL ADJACENT TO EXISTING F'ILL ADJOINING CANYON F'ILL DETAIL Plate E-4 ~ .. J L..,j L,J LA L._J L.~_A I. J l i I J I ! I 1 F 1 f 1 I" I k J l j t :. Drainage per design civil engineer oaa •.. Blanket fill (if recommended by the geotechnical consultant) Design finish slope -~ / / l_151oot I I minmum -I -i--------~-I 10-1oot minimum / l:: 7:: :0::: :7:: Y::-:'.: 25-foot maximum/ ., , ' '>' ' ,; . · . . · . . ---,<&--;: I Buttress or stabilization fill ~--4-inch-diameter non-perforated 2-Percent Gradent Typical benching (4-foot 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 minimum) Bedrock or approved native material Subdrain as recommended by geotechnical consultant 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. TYPICAL STABILIZATION / BUTTRESS FILL DETAIL Plate E-5 ; ... I . ""' J .. l ,,... •• ·1111111 •• ... ... ... :-: .. ; I I 2-toot I ...... I mnmum I 2-toot ---_c rnnnum _ l ·. t pipe nrinum Filter 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-Oiameter Pipe: ABS-ASTM 0-2751, SOR 35; or ASTM 0-1527 Schedule 40, PVC-ASTM 0-3034, SOR 35; or ASTM 0-1785 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. Additional 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.a 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 1Yi inch No.4 No.200 Percent Passing 100 50 8 TYPICAL BUTTRESS SUBDRAIN DETAIL Plate E-6 Li.I .._. ._.. La LA I.. J '° J l J f I I i I ! I 1 I 1 I I .---1 ~ l l l ~ Toe of slope as shown on grading plan Natural slope to be restored with compacted fill Backcut varies NOTES: .,,.,---Proposed grade \ / / / / / / -----r Subdrain as recommended by geotechnical consultant / Compacted fill 1. Where the natural slope approaches or exceeds the design slope ratio, special 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. .. a4111Jae. FILL OVER NATURAL {SIDEHILL FILL) DETAIL Plate E-7 L~ LJ L..i H • height of slope 1..J L.J L_J i, • • • Cut/fill contact as shown on grading plan Cut/fill contact as shown on as-built plan ----. Original (existing) grade • i .. . : i • i1 i . . I" 1 rwl r 1 I J • • l j i ' Proposed grade ~ ./ Compacted fill Subdrain as recommended by geotechnical consultant NOTE= The cut portion of the slope should be excavated and evaluated by the geotechnical consultant prior to construction of the fill portion. f. aA!ftJ.e. FILL OVER CUT DETAIL Plate E-8 Li liiW"i ... ~ L.I ~ J I i l I If t .. " Proposed finish grade .,_______,_ ------------ I I . . ! J Natural slope r 1 r 1 I J ( l l J t ' ~ :·.·=·· ····· , .. :··.<· ·:··:·. ·_.::.-._::,-. ' ' •:?<}::,:.:;:,~ \ .. . Typical benching (4-foot minimum) . . . : : . :· ...... : . ·.. . . .. ... . . ; . ,/"' \ \ , 1 1-foot mtnmurn tilt back . · .. , ..... ··~ / </ ,,\ :,..;'\' ·. . . . . ·:.. ,,,C--.=---=-- - - -~<-- - - - / \\/-~-----,/ ~ y\\\;((0, f Compacted stablization fill ~-Bedrock or other approved native material /" ~\\ / 'f;} If recommended by the geotechnical ~ ;;--consultant, the remaining cut portion of -'"r 2 Percent Gradient ---iY the slope may require removal and ~0v/\\ <\'\(<~ ~\, ,r replacement with compacted fill. j' \ '\ /,, /,-\ \ ,-\ \ ,:,,<\~\y\ I.... w ... I 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. a4IIIJ,e. j STABLIZATION FILL FOR UNSTABLE MATERIAL EXPOSED IN CUT SLOPE DETAIL I Plate E-9 ,,,_,~,.,,,,P l;l:'>-~'S''•.s,a--·---~--~~"'.e" "~ ... J ..._. ..i _. &;;.a L.I a. ~ I. ... I I i I J f 1 f 1 I I i 1 l ] i Proposed finish grade -~ Natural grade ------------------------.,,,,,,,.. 3 H • height of slope b~\\Y(\' >;; \ /,Y ,,-\ \ ' .. ·: :. ·:· : .. ; :_/ ........ v-:---'"~\ ·.·C . : ".' . '·' ... ·,. ·, ..... ,· ..• , .-.. ·• ~ {'<<\~\ Typical benching (4-foot minimum) .sk\?;<]~0.-w ._,,..__ 0&~J ~I~~\~ \\~::,,,: --~ 2-footminlmum , /\Y\\\\\\'.((0~~ \ \ key depth , ... 15-foot minimum key ~>-::.-\ v\ '{ ,, \ or H/2 if H>30 feet • I Subdrain as recommended by geotechnical consultant NOTES= 1. 15-foot minimum to be maintained· from proposed finish slope face to back cut. 3-foot tnlninlm 2. The need and disposition of drains will be evaluated by the geotechnical consultant based on field conditions. 3. Pad overexcavation and recompaction should be performed if evaluated to be necessary by the geotechnical consultant. a4IIIJ.e. SKIN FILL OF NATURAL GROUND DETAIL Plate E-10 a .. 1 _,.::.,,,..,............__~ --~-...... ~ .. ~~--·· -••• -L...i ~ &. ;J i ; I I • i & I Reconstruct compacted fill slope at 2:1 or flatter (may increase or decrease pad area) Overexcavate and recompact replacement fill Back-cut varies Avoid and/ or clean up spillage of materials on the natural slope If i • • I I .. . I 1 F" 1 1'···1 I 1 Natural grade Subdrain as recommended by geotechnical consultant ~ l l. 1 !. 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. c:418J.c. DAYLIGHT CUT LOT DETAIL Plate E-11 Natural grade Proposed pad grade . . . :. . ··: . . . : ·_. ... · .. · ... -·~.·:.:::z::!i-i1·,.;;.·· .. ,:~ - --- -- -- __ J_ ~V---Y>\ ~\Y~\~~~y\\\<('(.,..:;.;Y/\ /\\\«'~)/,,,\\;(\~\'/.,)/~\ {(0.0\y\\\; '/ 3-to 7-foot ~ ~ overexcavate and recompact ~\...,,../'....,,.~~\ Bedrock or per text or report .--\ \ ::..<, approved native material Typical beAChing CUT LOT OR MATERIAL-TYPE TRANSmON Typical benching (4-foot minimum) Natural grade . ····:. ... : . . . . ·:··+·:·-~~~---·_ .. ,: - - -j_ Bedrock or approved native material • Deeper overexcavation may be recommended by the geotechnical consultant in steep cut-fill transition areas, such that the underlying topography is no steeper than 3:1 (H:V) CUT-FILL LOT (DAYLIGHT TRANSmON) G..... TRANSITION LOT DETAILS Plate E-12 - .,. .J ~ • 1111111 • 11111! ~ ;1 Iii ij ""' ! i I ... ·~ 111111 D g I VIEW NORMAL TO SLOPE FACE Proposed finish grade ~ (E)~ ~ 1:--~ ' (E) Hold-down depth /' ,..cco c[J c[J // ~, = ~= /' c:co c[J t c:co c[J (\ I W I ~ ~ cD-15-foot-cco _ c[J cco CCC) -=1 (B) c[J d9> CCO(F) ~0s~\~~~%~~~~~0~>%< 'y-Bedrock or approved minimum native material VIEW PARALLEL TO SLOPE FACE j_ __ ~ (E) Hold-clown depth NOTES: (D) ~ Bedrock or approved native material 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 feet. 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 as 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 DIAGRAMMATIC ONLY AND MAY BE SUPERSEDED BY REPORT RECOMMENDATIONS OR CODE ROCK SHOULD NOT TOUCH AND VOIDS SHOULD BE COMPLETELY FILLED OVERSIZE ROCK DISPOSAL DETAIL Plate E-13 !~ .! •• ' t ! HIIIII I 11111 J J- J l 1 ' 11111 I .J ROCK DISPOSAL PITS Fill lifts compacted oyvr rock after embedment r------- 1 ..... Granular material L _ _ _ Large Rock I I I I Compacted Fill I ------1 ~ Size of excavation to : be commensurate I with rock size I ROCK DISPOSAL LA YEAS Granular soil to fill voids, densified by flooding .-__ -{ ~mpacte~fi~ _ .. Layer one rock~ ~ J(__Jt'.2£y t L_ Proposed finish grade· ,~~~ ~~ ·· -:-Had-down;;---~ " ~LE ALQOO-LA~;--t- oversize layer "(·---- _t Compacted fill 3-foot " minimum lFill Slope l -aear zone TOP VIEW Layer one rock high • Hold-down depth or below lowest utility as specified in text of report, subject to governing agency approval. •• Clear zone for utility trenches, foll'ldations, and swimming 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 ALLED IN ROCK DISPOSAL DETAIL Plate E-14 • ~' • C C f!! I I iC 'c ~. ; ' ·' ' 11 ':'" i 1. i·.t. C·· 'l .1 ' . ""' "'"' 11111 Existing grade 5-f cot-high impact/debris wall METHOD 1 1 Pad grade -_L __ --- Existing grade 5-foot-high impact/ debris wall METHOD2 Existing grade 5-foot-wide catchment area ( s-foot-high METHOD 3 impact/debris wall ~~-_ ~ Pad gra~ <\ /;' \\, \,, ,,-\/, /, Existing grade ~\: 2:1 (h:v) slope cence -\\1~ \ 2=1 (h:v) slope METHOD 4 0--\ \.--_r-Pad grade ·\\\ '-_[_ - - ~ ,; NOTTO SCALE DEBRIS DEVICE CONTROL METHODS DETAIL Plate E-15 ,.,., r"'' l I 11ii, -•• Rock-filled gabion basket Existing grade ~..... A .J>-.,.. i"' 1\. ,\ g ,, ./\ -r;;;cr;;;c ..... T>;(J.lJ.l µ.. J-"'4. '"' P.<! )"'< ~ Filter fabric ~ Drain rock Compacted fill Proposed grade 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 ..,., "'"' 1111 11111 1111111 MAP VIEW NOTTO SCALE Concrete cut-off wall SEE~~S~~~~~~~~~~ Bl Gravity-flow, nonperforated subdrain I=-== pipe (transverse) Toe of slope 4 2-inch-thick sand layer Pool 4-inch perforated subdrain pipe (longitudinal) Coping A' 4-inch perforated subdrain pipe (transverse) Pool Direction of drainage B' CROSS SECTION VIEW Coping NOTTO SCALE SEE NOTES Pool encapsulated in 5-foot thickness of sand --~ 6-inch-thick gravel layer 4-inch perforated subdrain pipe B r H NOTES: Gravity-flow nonperforated subdrain pipe Coping B' 2-inch-thick sand layer Vapor retarder Perforated subdrain pipe 1. 6-inch-thick, clean gravel(% to '!)a 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 2. Pools on fills thicker than 20 feet should be constructed on deep foundations; otherwise, distress (tilting, cracking, etc.) should be expected. 3. Design does not apply to infinity-edge pools/spas. TYPICAL POOL/SPA DETAIL Plate E-17 I I I I Ir [ [ [ C ---------------------------------------- -t- NOTES: 2-foot x 2-foot x '4-inch steel plate Standard %-inch pipe nipple welded to top of plate ---1--%-inch x 5-foot galvanized pipe, standard pipe threads top and bottom; extensions threaded on both ends and added in 5-foot increments 3-inch schedule 40 PVC pipe sleeve, add in 5-foot increments with glue joints Proposed finish grade bedding of compacted sand 1. Locations of settlement plates should be clearly marked and readily visible (red flagged) to equipment operators. 2. Contractor should maintain clearance of a 5-foot radius of plate base and withiin 5 feet (vertical) for heavy equipment. Fill within clearance area should be hand compacted to project specifications or compacted by alternative approved method by the geotechnical consultant (in writing, prior to construction). 3. After 5 feet (vertical) of fill is in place, contractor should maintain a 5-foot radius equipment clearance from riser. 4. Place and mechanically hand compact initial 2 feet of fill prior to establishing the initial reading. 5. In the event of damage to the settlement plate or extension resulting from equipment operating within the specified clearance area, contractor should immediately notify the geotechnical consultant and should be responsible for restoring the settlement plates to working order. 6. An alternate design and method of installation may be provided at the discretion of the geotechnical consultant. SETTLEMENT PLATE AND RISER DETAIL Plate E-18 "----"-""'--~'"" "'""~"'i·,,, ""'"~"' ~.,,.~,~'~"" -•" '"--.,..,_,,, ·•~ ·· ., ~~.,.;:,.,.:,,:et,!:io!i!!e'/!' .. ,,-. . .,.~----~~,,,, _____ ...... IC'I E31 C',I F""I F"'l I'", r"1 r+~, r-, r. P''"'.I ~ ~ F4 -•• • I I 1 I I Finish grade \ ~ < -%-inch-diameter X 6-inch-long ~ -LI <1 carriage bolt or equivalent <1 - <1 LI LI <1 6-inch diameter X 3 to 6 feet LI 3~-inch-long hole '-L'.I <1 LI <I <1 "~ L'.I" " ~ LI LI<] Concrete backfill • j ---- Q ..... TYPICAL SURFACE SETTLEMENT MONUMENT Plate E-19 D C C C C C C C C I t I I C I I I I I SIDE VIEW Test pit TOP VIEW Flag Flag Spoil pile Test pit Light Vehicle -----50feet----------50feet----- -------------100fee,r------------- TEST PIT SAFETY DIAGRAM Plate E-20