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HomeMy WebLinkAboutCT 12-07; Valley 17; Soils Report; 2013-10-24ALTA CALIFORNIA GEOTECHNICAL INC. CITY VENTURES 1900 Quail Street Newport Beach, California 92660 FILE COPY 170 North Maple Street, Suite 108 Corona, CA 92880 www.altageotechnical.com October 24, 2013 Project Number 2-0068 Attention: Mr. Andy Gerber Director of Development Subject: PRELIMINARY GEOTECHNICAL INVESTIGATION Tentative Tract CT 12-07, Vajley Street and Oak Avenue City of Carlsbad, California i References: See Appendix A Mr. Andy Gerber: Presented herein Is Alta California Geotechnical, Inc's (Alta) prelimmary geotechnical investigation of Tentative Tract CT 12-07, Ic^cated at Valley Street and Oak Avenue, in the City of Carlsbad, County of San Diego, California, the conclusions and recommendations presented in this report are based on Alta's subsurface ir]vestlgation, the enclosed Tentative Map (Sheet 2 of 3) provided by Huitt-Zollars, laboratory testing and review ofthe referenced reports. Alta's review of the data and site plan indicates that the proposed development is feasible, from a geotechnical standpoint, provided that the recommendations presented in this report are incorporated into the grading and imprcjvement plans, and implemented during site development. Included in this report are: • Discussion of the site geotechnical conditions; • Recommendations for remedial and site grading, including unsuitable soil removals; • Geotechnical recommendations for ^ite construction; • Preliminary foundation design parameters. 00 3 CO DC 5 San Diego Office Phone: 858 674.6636 Corona Office Phone: 951.509.7090 Project No. 2-0068 October 24, 2013 Page 2 Alta California Geotechnical, Inc. appreciates the opportunity to present this proposal. We wil be happy to meet with you regarding the project at your convenience. Should you have any questions, please contact the undersigned at our Corona or San Diego offices. Sincerely, Alta California Geotechnical,rtnc. SCOTT Af^RAY/RGE 28= Reg. Exp.: 12-31-2^^mio^ RegisteredGeoJ " ^ Vice Presidenti Distribution: (1) Addressee SAG/DAM: skt-2-0068, October 24, WID A. MURPHV/q Reg. Exp.: 10-31-15 Certified Engineering President 1813 Geologist lnvestigati(^n Valley and Oak) ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 1.0 INTRODUCTION Page 3 Table of Contents 6 1.1 Purpose 1.2 Scope of Work 1.3 Report Limitations, 6 6 7 2.0 PROJECT DESCRIPTION g 2.1 Site Location and Existing Conditions 8 2.2 Proposed Development 8 3.0 SITE INVESTIGATION j 9 4.0 GEOLOGIC CONDITIONS j 9 4.1 Geologic and Geomorphic Setting 9 4.2 Stratigraphy 9 4.2.1 Topsoil (no map symbol) 10 4.2.2 Old Paralic Deposits (map symbol Qop) 10 4.3 Geologic Structure 10 4.3.1 Tectonic Framework.. 10 4.3.2 Geologic Structure H 4.4 Groundwater H 4.5 Earthquake Hazards 12 4.5.1 Surface Rupture 12 4.5.2 Liquefaction 12 13 13 14 4.5.3 Seiches 4.5.4 Tsunami 4.5.5 Dry Sand Settlement 4.5.6 Seismically Induced Landsliding 14 5.0 ENGINEERING PROPERTIES AND ANALYSIS 14 5.1 Materials Properties 14 5.1.1 Excavation Characteristics 14 5.1.2 Hydro-Consolidation 14 5.1.3 Compressibility | 15 5.1.4 Expansion Potential..] 15 5.1.5 Shear Strength Characteristics 15 5.1.6 Earthwork Adjustments 16 5.1.7 Chemical Analyses 16 5.1.8 Pavement Support Characteristics 16 5.2 Engineering Analysis 17 ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 4 6.0 5.2.1 Bearing Capacity anc| Lateral Earth Pressures 17 CONCLUSIONS AND RECOMMENDATIONS 17 6.1 6.2 6.3 6.1.2 6.1.3 6.1.4 6.1.5 6.1.6 6.1.7 6.1.8 6.1.9 6.1.12 Utility Trenches. 6.1.13 Backcut Stability Slope Stability General Earthwork Recommendations 17 6.1.1 Site Preparation i 18 Unsuitable Soil Remo vals 18 Over-excavation 18 Compaction StandanJs 19 Documentation of Removals 19 Treatment of Removal Bottoms 20 Fill Placement 20 Benching ^ 20 Mixing j 20 6.1.10 Import Soils \ 21 6.1.11 Fill Slope Construction 21 22 23 24 7.0 DESIGN CONSIDERATIONS. Storm Water Infiltration Systems 24 .25 7.1 Structural Design 25 7.1.1 Foundations 25 7.1.2 Post-Tensioned Slabs/Foundation Design Recommendations 26 7.1.3 Conventional Foundation Systems 26 7.2 Moisture Barrier 27 7.3 Seismic Design 28 7.4 Retaining Wall Design 28 7.5 Fence and Garden Walls 30 7.6 Footing Excavations 30 7.7 Exterior Slabs and Walkways 31 7.7.1 Subgrade Compaction 31 7.7.2 Subgrade Moisture 31 7.7.3 Concrete Slab Thickness 31 7.7.4 Concrete Slab Reinforcement 31 7.7.5 Control Joints 32 Concrete Design 32 Corrosion ^ 32 Pavement Design [ 32 Site Drainage 33 Deepened Footings and Setb|acks 34 7.8 7.9 7.10 7.11 7.12 ALTA CALIFORI|IIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Pages 8.0 FUTURE PLAN REVIEWS 35 9.0 CLOSURE 35 9.1 Geotechnical Review 35 9.2 Limitations 3^ APPENDIXA: REFERENCES APPENDIX B: PREVIOUS SUBSURFACE INVESTIGATION APPENDIX C: PREVIOUS LABORATORY TESTING APPENDIX D: EARTHWORK SPECIFICATIONS APPENDIX E: GRADING DETAILS POCKET ENCLOSURE: SHEET 2 OF 3: SO-SCJALE TENTATIVE TRACT MAP NO. 12-07 ALTA CALIFORINIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 6 1.0 INTRODUCTION This report contains Alta California (geotechnical, Inc.'s (Alta's) findings, conclusions, and geotechnical recommendations for the development of Tentative Tract 12-07, located at Valley Street and Oak Avenue, in thu City of Carlsbad, California. 1.1 Purpose The purpose of this report is ^o examine the existing geotechnical conditions and evaluate their impact on the proposed residential development depicted on the enclosed 30-scale Tentative Tract Map (Sheet 2 of 3). This report is intended to be suitable for submittal to g(^verning agencies and for use as a contractor bid document. 1.2 Scope of Work Alta's Scope o/l/l/or/f forthis geotechnical investigation Includes the following: • Reviewing the referenced maps pertinent tothe; Review ofthe May 2012 (2012), which consisted hollow-stem auger bbrlngs existing surface (Apptmd literature, reports, aerial photographs and subject site; subsurface investigation conducted by Alta of excavating, logging, and sampling of three (3) to a maximum depth of 17 feet below the Ix B); • Preliminary non-spec fic preliminary infiltration testing in two (2) hand- auger borings up to a depth of two feet below existing ground surface (Appendix B); • Review of the previous laboratory testing conducted by Alta (2012), on samples obtained during our previous investigation (Appendix C) including the following tests: laboratory maximum dry density and optimum moisture content, moisture/density, expansion index, direct shear, consolidation, grain size analysis, and chemical (corrosion) testing; • Preparation of a geolcigic map; • Discussion of existing isite conditions; ALTA CALiPORrjiA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 7 Seismic hazards evaliliation; Summarize the engineering characteristics ofthe onsite soils and discuss the use of onsite soil^ as a foundation medium; Develop grading reccjmmendations including unsuitable soil removals; Provide preliminary ijearing and friction values; j Preliminary recommendations for concrete slab and foundation design parameters; '. Provide earth pressures for retaining walls; Provide code-consistent seismic coefficients for design; Estimate shrink/swel| parameters; Evaluating engineering geologic and geotechnical engineering data, including laboratory data, to develop preliminary recommendations for site grading, foundat ons, retaining walls and utilities; Preparing this report and accompanying exhibits. 1.3 Report Limitations The conclusions and recomdiendatlons in this report are based on: 1) the data developed during our previous investigation and laboratory testing (Alta 2012); 2) a review ofthe referenced reports, maps and air photos. The materials immediately adjacent to or t^eneath those observed may have different characteristics than those otiserved and no representations are made as to the quality or extent of material not observed. The information contained in this report is intended to be use(|l for development of grading plans and preliminary construction cost estimates. It is Alta's understanding thc|t remediation ofthe soil onsite may be required for environmental concerns (Stalntec, 2012). Environmental assessments are not part ofthe scope ofthis investigation. The recommendations presented herein are concerning the geotechnical properties ofthe onsite soils only. ALTA CALIFOF^NIA GEOTECHNICAL, iNC. Project No. 2-0068 Page 8 October 24, 2013 2.0 PROJEa DESCRIPTION 2.1 Site Location and Existing Conditions The rectangular-shaped site (jonsists of approximately 3.76-acres located at the south corner of the intersection of Valley Street and Oak Avenue, in the City of Carlsbad, County of San DiegQ, California (Figure 1). Topographically, the site is relatively flat and gently slopes to the west. Elevations range from approximately 169 to 154 feet. The site is currently vacant. It is our understanding that the site has historically been used for agricultural purjposes. Native grasses and weeds cover the majority of the site. Some trees are pijesent at the eastern corner of the site, as well as at the southwest corner of the s|te, near the terminus of the existing James Drive. 2.2 Proposed Development The proposed development c|)nsists ofthe extension of James Drive from Valley Street to the south corner of Ijhe site as shown on enclosed Sheet 2 of 3, and the development of seventeen (l{7) lots for single family residences. Infrastructure improvements are proposed, |ncludingthe construction water, sewer and storm drain in proposed James Driv^. Some underground and surface improvements are also proposed for the exisjting Oak Avenue and Valley Street. Lot elevations are proposed from a high of 1^9.0 feet in the northeast portion ofthe site to a low of 159.4 feet on the south edge of the property. Earthwork estimates prepared by the project civil engineer are: 1,878 cubic yards of cut, 10,982 cubic yards of fill and 9,104 cubic y^rds of import. It is Alta's understanding that ^portions of the soil onsite may require remediation i for environmental concerns. The scope ofthe remediation is not known at this time. ALTA CALIFORNIA GEOTECHNICAL, INC. OCEANSIDE SITE LOCATION MAP USGS SAN LUIS REY QUADRANGLE, 2012 SCALE: r = 2000' RGURE 1 A ALTA CALIFORNIA GEOTECHNICAL. INC. 16870 WEST eeRNARDO DRIVE. SUITE 445. SAN DIEOO. CA 92127 y«2^^ \ TElfPHONE: (858) 674-0636 ' nOJRT NIMHR: I-OOn DMEi 10-24-13 Project No. 2-0068 Page 9 October 24, 2013 3.0 SITE INVESTIGATION Alta conducted a subsurface investigation ofthe subject site in May of 2012, consisting ofthe excavation, logging and selective sampling of three (3) hollow-stem auger borings and two (2) hand-auger test pits. TIjie locations ofthe borings are shown on enclosed Sheet 2 of 3, and the logs are presented in Appendix B ofthis report. I Laboratory testing was performed i6 2012 on relatively "undisturbed" ring samples and bulk samples obtained during our fi^ld investigation. A brief description of laboratory test procedures and the test resultsjare presented in Appendix C. 4.0 GEOLOGIC CONDITIONS 4.1 Geologic and Geomorphic Setting Regionally, the site is located in the Peninsular Ranges geomorphic province, which characterizes the southwest portion of southern California. The Peninsular Ranges province is composedj of plutonic and metamorphic rock, lesser amounts of Tertiary volcanic and sedinjentary rock, and Quaternary drainage in-fills and sedimentary veneers. The prjjposed project is located in the Santa Ana sub-block (Jennings, 1985), which is boijnded bythe Elsinore fault zone on the east and by the Newport-Inglewood fault jzone on the west. 4.2 Stratigraphy A digital preparation of geologic mapping by Kennedy and Tan (2005) depicts the project to be underlain by "Old Paralic Deposits". These deposits are described by Kennedy and Tan as middl^ Pleistocene-age, poorly sorted, reddish brown, strandline, beach, estuarine, and colluvial deposits composed of siltstone, sandstone, and conglomeratej. This unit has commonly been called terrace 1 deposit. Alta encountered thi's unit as well as topsoil generated from these deposits. ALTA CALiF0Rf|iiA GEOTECHNICAL, INC. Project No. 2-0068 Page 10 October 24, 2013 The geologic units are brieflyidescribed below. Their distribution is shown on the enclosed Sheet 2 of 3. 4.2.1 Topsoil (no map syn^bol) Assumed to be locally derived from the weathered Old Paralic Deposits and from agricultural processes, a relatively thin layer of topsoil was encountered in the upper 1.5 to 2 feet at the site. The topsoil consists predominantly of light yellow brown to brown fine grained silty sands, I that is slightly moist to moist, and loose. 4.2.2 Old Paralic Deposits '(map symbol Qop) Pleistocene-age depcjsits termed "Old Paralic Deposits" by Kennedy and Tan (2005) underlie t|ie development area. These deposits were observed to consist of light reddish brown to dark reddish brown fine to medium grained silty sandstone, which is slightly moist to moist and dense to clay cemented, with some manganese oxide. The upper one- foot ofthis unit was (j»bserved to be weathered. 4.3 Geologic Structure 4.3.1 Tectonic Framework Jennings (1985) defined eight structural provinces within California that I have been classified by predominant regional fault trends and similar fold structure. These provinces are in turn divided into blocks and sub-blocks that are defined by "rViajor Quaternary faults". These blocks and sub- blocks exhibit similar Structural features. Within this framework, the subject site is located within Structural Province I, which is controlled by the dominant northwest trend ofthe San Andreas Fault and is divided into two blocks, the cjoast Range Block and the Peninsular Range Block. I The Peninsular Range[ Block, on which this site is located, is characterized ALTA CALIFORHIA GEOTECHNICAL, INC. Project No. 2-0068 Page 11 October 24, 2013 by a series of parallel, northwest trending faults that exhibit right lateral dip-slip movement. These faults are terminated by the Transverse Range block to the north ar^d extend southward to the Baja Peninsula. These northwest trending faults divide the Peninsular Range block into eight sub-blocks. The site Is located within the Santa Ana sub-block, one ofthe eight sub-blocks, and is bound on the west by the Newport-Inglewood fault zone and on th^ east by the Elsinore fault zone. I 4.3.2 Geologic Structure i Based upon our site investigation and literature research, the onsite Old Paralic Deposits have| not been folded, faulted or fractured. The deposits are typically massive with horizontal contacts and fining upwards sequences. Several large, active fault systems occur in the region surrounding the subject site. These f^ult systems have been studied extensively and in a large part control thej geologic structure of southern California. The closest active fault to the site is the offshore segment ofthe Newport- Inglewood fault, locajed 5.6 miles from the site. The property is not located within an Alquist-Priolo earthquake fault zone. 4.4 Groundwater Groundwater was not encountered during this firm's current subsurface investigation. The depth to groundwater at the intersection of Carlsbad Village Drive and Interstate 5 is reported to be approximately 15 feet below the surface (Gregg Drilling and Testing, 2C|00), for a corresponding elevation of 73 feet above sea level. Considering this data and interpolating to the site Alta estimates the depth to groundwater below ^he subject site is approximately 90 feet below the ground surface. ALTA CALIFORI^IIA GEOTECHNICAL, INC. Project No. 2-0068 Page 12 October 24, 2013 4.5 Earthquake Hazards The subject site is located in southern California, which Is a tectonically active area. The type and magnitucje of seismic hazards affecting a site are dependent on the distance to the causative fault and the intensity and magnitude ofthe seismic event. The seismic hazard may be primary, such as surface rupture and/or ground shaking, or sej:ondary, such as liquefaction and/or ground lurching. 4.5.1 Surface Rupture "Active" faults have rjiot been identified on the subject site, and therefore the probability of prilnary surface rupture or deformation at the site is considered unlikely. Ground shaking haza^-ds caused by earthquakes along active regional faults do exist. The ^010 California Building Code requires use-modified spectral acceleration^ and velocities for most structural designs. Seismic i design parameters u^ing soil profile types identified in the 2010 California Building Code are presented in Section 7.3. 4.5.2 Liquefaction Seismic agitation of relatively loose saturated sands, silty sands, and some silts can result |n a buildup of pore pressure. Ifthe pore pressure exceeds the overburqien stresses, a temporary quick condition known as liquefaction can occu|r. Liquefaction effects can manifest in several ways including: 1) loss of tjearing; 2) lateral spread; 3) dynamic settlement; and 4) flow failure. Lateral spreading has typically been the most damaging mode of failure. ALTA CALIFOI^NIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 13 In general, the more recent that sediment has been deposited, the more likely it will be suscebtible to liquefaction. Other factors that must be considered are: groundwater, confining stresses, relative density, and the Intensity and durlation of seismically-induced ground shaking. The "Old Paralic Deposits" that exist beneath the site, are generally resistant to liquefact|on. Because ofthis, and the relatively deep groundwater depth ^t the site, liquefaction at the site is considered to be unlikely. 4.5.3 Seiches A seiche is a free or s|tanding-wave oscillation on the surface of water in I an enclosed or semi-fenclosed basin. The wave can be initiated by an earthquake and can jary in height from several centimeters to a few meters. The potential for a seiche impacting the property Is considered to be non-existent. 4.5.4 Tsunami A tsunami is a great sea wave produced by a submarine earthquake, eruption. It is characterized by great speed of observable amplitude on the open sea but can attain heights of seve ral tens of feet upon encountering shallow water. Significant damage can occur along coastal areas subjected to such a wave. The site is not within the State of California Tsunami Inundation Zone (USGS, 2009), ajid due to the elevation ofthe site above sea level, the chance for a tsunlami hazard is considered minimal. landslide, or volcanic propagation and low ALTA CALIFORLA GEOTECHNICAL, INC. Project No. 2-0068 Page 14 October 24, 2013 4.5.5 Dry Sand Settlemenj I Dry sand settlement |is the process of non-uniform settlement ofthe i ground surface durinjg a seismic event. Upon completion of site grading as recommended hefein, the potential for this type of settlement will be minimal. 4.5.6 Seismically Induced |.andsliding Due to a lack of natural slopes within or around the property, seismically induced landsliding is not anticipated to pose a danger to the site. 5.0 ENGINEERING PROPERTIES AND ANALYSIS 5.1 IVIateriais Properties | I Presented herein is a general discussion ofthe engineering properties ofthe onsite materials that will be pncountered during construction ofthe proposed I project. Descriptions ofthe ^oil and in-place moisture/density results are presented on the boring logs in Appendix B. 5.1.1 Excavation Characteristics Based on the data pr(j)vided from the subsurface investigation, it is our I opinion that the majcirlty of the on-site materials possess favorable excavation characteristics. It is possible that well-cemented sections of the Old Paralic Depos|its may exist and would require moderately difficult ripping. j 5.1.2 Hydro-Consolidation Hydro-consolidation ijs the effect of introducing water into soil that is prone to collapse. Upjon loading and initial wetting, the soil structure and i apparent strength ar^ altered resulting in almost immediate settlement. That settlement can h|ave adverse impacts on engineered structures, ALTA CALiFORijiiA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 15 particularly in areas jvhere it Is manifested differentially. Differential settlements are typi(|ally associated with differential wetting, irregularities in the subsurface soil conditions, or irregular loading patterns. The underlying Old Paralic Deposits generally have a low potential for hydro-collapse. A sahd lens was encountered in the sample in boring B-3 at 8-feet. Testing on this sample indicated that there may be a potential for hydro-collapse within these isolated sand lenses. However, based on the proposed fill heights and loading, and the recommended removals, the potential for hydi o-collapse to occur at the site will be low and within foundation design to erances upon the completion of recommendations presented herein. Design settlement recommendations are presented in Table 7-1. 5.1.3 Compressibility The topsoil and highly weathered Old Paralic Deposits are considered compressible and unsuitable to support the proposed improvements. Unsuitable soil remoyal recommendations are presented in Section 6.1. 5.1.4 Expansion Potential Expansion index testijig was performed on samples taken during Alta's investigation. Based jjn Alta's results, it is anticipated that the majority of materials onsite will vary in expansion potential from "very low" to "low". 5.1.5 Shear Strength Characteristics Direct shear testing vvjas performed to assist in the development of shear strength characteristi[:s ofthe onsite soils. The values presented in Table ALTA CALIFOR|JIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 16 5-1 are based on Alto's laboratory testing, and our previous experience with similar material?. TABLE 5-1 Shear Strength Characteristics Geologic Unit Cohesion, C (psf) Friction Angle, ^ (degrees) Engineered Arttlflcial Fill 200 30 5.1.6 Earthworlc Adiustme|nts I The values presentecj in Table 5-2 are deemed appropriate for estimating purposes and may b0 used in an effort to balance earthwork quantities. As is the case with e\^ery project, contingencies should be made to adjust i the earthwork balance when grading is in-progress and actual conditions are better defined. TABLE 5-2 Earthwork Adjustment Factors Geologic Unit Adjustment Factor Range Recommended Average Topsoil Shrink 15 to 20% 18% Old Paralic Deposits Shrink 0 to 6% 4% 5.1.7 Chemical Analyses ; Chemical testing was performed on one samples of material underlying the proposed site. Sbluble sulfate test results indicate that the soluble sulfate concentration ACI 318-08. Chloride s ofthe soils tested are classified as negligible per levels of 56 ppm were detected in the onsite soils, which are generally cjonsidered low (CalTrans, 2003). Resistivity testing indicates that the soi|s are mildly corrosive to buried metals (Romanoff, 1989). 5.1.8 Pavement Support c(iaracteristics The onsite soils can b^ expected to provide moderate pavement support characteristics. While R-value testing has not been conducted, it is likely ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 Page 17 October 24, 2013 that R-values of 20 tcj) 30 will be produced by the majority of onsite earth materials. Specific testing should be conducted upon completion of I grading and be used as a basis for design of pavement. 5.2 Engineering Analysis Presented below is a general discussion ofthe engineering analysis methods that were utilized to develop the conclusions and recommendations presented in this report. 5.2.1 Bearing Capacity anc^ Lateral Earth Pressures Ultimate bearing capacity values were obtained using the graphs and formula presented in NAVFAC DM-7.1. Allowable bearing was determined by applying a factor of safety of at least 3 to the ultimate bearing capacity. Static lateral earth pressures were calculated using Rankine methods for active and passive cases. If it is desired to use Coulomb forces, a sejiarate analysis specific to the application can be conducted. 6.0 CONCLUSIONS AND RECOMMEND/^TIONS Based on Alta's findings during our Subsurface investigation, the laboratory test results, our staff's previous experience in th^ area, and a review ofthe referenced reports, it is Alta's opinion that the development! of the site is feasible from a geotechnical perspective. Presented below are recommendations that should be incorporated into site development and construction plans. 6.1 General Earthwork Recommendations All grading shall be accomplished under the observation and testing of the project I geotechnical consultant in accordance with the recommendations contained herein and the requirements 0f the City of Carlsbad. ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 Page 18 October 24, 2013 6.1.1 Site Preparation Vegetation, ajid other deleterious materials, such as crushed asphalt are ur^suitable as structural fill material and should be disposed of o^-site prior to commencing grading/construction. 6.1.2 Unsuitable Soil Removals Presented be(ow are the unsuitable soil removal recommendations forthe onsite geologic units. All removal bottoms should be observed bythe Project Geotechnical Consultant in the field during grading to determine that suitable (non-weather{ed, limited porosity) soils have been exposed. 6.1.2.1 Topso The topsoil onsite is unsuitable to support the proposed fills and/or structures and should be removed and recompacted to project specifications. Removal depths are esUmated to be one (1) to two (2) feet within this unit. 6.1.2.2 Old Paralic Deposits The upper portions ofthe Old Paralic deposits should be procesjsed and recompacted to eliminate the dry weathered portion before placement of additional fill or structures. It is anticipated that the upper two (2) to three (3) feejt ofthis material will require removal and recompaction. 6.1.3 Over-excavatilon Lots should be underlain by a minimum of three (3) feet of compacted fill. Based upon review ofthe enclosed 30-scale ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 Page 19 October 24, 2013 Tentative Trakt Map 12-07, after completion ofthe recommended i remedial graqling described above in Section 6.1.2 ofthis report, minimum fill jthicknesses are anticipated to be three (3) feet or greater beneath the building pads. Final determination of this anticipated condition should be made in the field during grading. Wherever thi^ condition is not met any cut and shallow fill portion building pads should be over-excavated to a depth that is sufficient to provide a minimum of three (3) feet of compacted fill. Over-excavations should be observed and approved by the Project Geotechnical Consultant in the field during grading. 6.1.4 Compaction Standards All fill and processed natural ground shall be compacted to a minimum relative compaction of 90 percent, as determined by ASTM Test Msthod: D-1557. Fill material should be moisture conditioned to optimum moisture or above, and as generally discussed in /Jta's Earthwork Specification Section presented in Appendix D. jcompaction shall be achieved with the use of sheepsfoot rcllers or similar kneading type equipment. Mixing and moisture conditioning will be required in order to achieve the recommended moisture conditions, j 6.1.5 Documentatijon of Removals All removal aijid over-excavation bottoms should be observed and approved by the project Geotechnical Consultant prior to fill I placement. [Removal bottoms and undercuts should be surveyed after approva|l by the geotechnical consultant prior to the ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 20 placement of fill. Staking should be provided in order to verify undercut loc<itlons and depths. 6.1.6 Treatment of Removal Bottoms At the completion of removals and over-excavation, the exposed bottom should be ripped to a minimum depth of eight inches, moisture-conlditioned to above optimum moisture content and compacted in -place to the project standards. 6.1.7 Fill Placement After remova s, scarification, and compaction of in-place materials are completejd, additional fill may be placed. Fill should be placed in eight-inch bulk maximum lifts, moisture conditioned to optimum mo sture content or above, compacted and tested as grading/construction progresses until final grades are attained. 6.1.8 Benching Where the natural and where des compacted fi competent 0 slope is steeper than 5-horizontal to 1-vertical ignated by the project Geotechnical Consultant, I material shall be keyed and benched Into d Paralic Deposits or firm artificial fill. 6.1.9 Mixing Mixing of ma1}erials may be necessary to prevent layering of different soil Hypes and/or different moisture contents. The mixing should be accomplished prior to and as part of compaction of each fill lift. ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 21 6.1.10 Import Soils Based on a review ofthe Tentative Tract Map, import soils will be required to bl-ing the site to the proposed design. Import soils should consist of clean, structural quality, compactable materials similar to thejon-site soils and should be free of trash, debris or other objecti<j)nable materials. The project Geotechnical Consultant should be notified not less than 72 hours In advance of the locations ^f any soils proposed for import. Import sources should be sarjipled, tested, and approved by the project Geotechnical Consultant at the source prior to the importation of the soils to the site. The project Civil Engineer should include I these requirefnents on plans and specifications for the project. 6.1.11 Fill Slope Construction Fill slopes shojuld be overfilled to an extent determined bythe contractor, bdit not less than two (2) feet measured perpendicular to the slope fuce, so that when trimmed back to the compacted core a minimum 90 percent relative compaction is achieved. Compaction cf each fill lift should extend out to the temporary slope face. Buck-rolling during mass filling at intervals not exceeding foL r (4) feet in height is recommended, unless more extensive overfilling Is undertaken. As an alternaltive to overfilling, fill slopes may be built to the finish slope face in Accordance with the following recommendations: 1. Compaction of each fill lift should extend to the face ofthe slopes^ ALTA CALIFOI^NIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 22 Back-rjolling during mass grading should be undertaken at intervals not exceeding four (4) feet In height. Back-rolling at moj-e frequent intervals may be required. Care should be taken to avoid spillage of loose materials down the face of any slopes during grading. Spill fill will require complete removal priorto compaction, shaping, and grid rolling. At conjipletion of mass filling, the slope surface should be watered, shaped, and compacted by track walking with a D-8 biiilldozer, or equivalent, such that compaction to projecjt standards is achieved to the slope face. Proper seedling and planting of the slopes should follow as soon as practical to inhibit erosion and deterioration ofthe slope surfaces. Proper moisture control will enhance the long-term stability of the finish slope surface. I 6.1.12 Utility Trencl^es 6.1.12.1 ixcavatl(|>n Utility tranches should be supported, either by laying back excavations or shoring, in accordance with applicable OSHA standards. In general, existing site soils are classified as Soil Types "B" per OSHA standards. Upon completion ofthe I recommended removals and recompaction, the artificial fill will be classified as Soil Type "B". The Project Geotechnical Consultirg should be consulted if geologic conditions vary from what is presented in this report. 6.1.12.2 Backfill Trench buckfill should be compacted to at least 90 percent of maximunji dry density as determined by ASTM D-1557. ALTA CALIFOF|NIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 23 Onsite soils will not be suitable for use as bedding material but will be suitable for use in backfill provided oversized material^ are removed. No surcharge loads should be j imposed above excavations. This Includes spoil piles, lumber, concrete trucks, or other construction materials and equipment. Drainage above excavations should be directed I away fro|n the banks. Care should be taken to avoid saturation ofthe soils. Compaction should be accomplished by mechanical means. Jetting of native soils will not be acceptat^le. 6.1.13 Backcut Stabilitv Temporary backcuts, if required during unsuitable soil removals, should be made no steeper than 1:1 without review and approval ofthe geotechnical consultant. Flatter backcuts may be necessary where geologjc conditions dictate and where minimum width dimensions are to be maintained. Care should be taken during remedial grading operations in order to minimize ri^ of failure. Should failure occur, complete removal of th^ disturbed material will be required. In consideration ofthe inherent instability created by temporary construction tjackcuts for stabilization fills and removals, it is I imperative thdit grading schedules are coordinated to minimize the unsupported exposure time of these excavations. Once started these excavations and subsequent fill operations should be maintained! to completion without intervening delays imposed by avoidable c|rcumstances. In cases where five-day workweeks ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 Pagg 24 October 24, 2013 comprise a n(|)rmal schedule, grading should be planned to avoid exposing at-g|-ade or near-grade excavations through a non-work weekend. Where improvements may be affected by temporary instability, either on or offsite, further restrictions such as slot cutting, extenjding work days, implementing weekend schedules, i and/or other Requirements considered critical to serving specific circumstance^ may be imposed. 6.2 Slope Stability Fill slope stability can be affected by several factors including geologic structure, strength of materials, height^ inclination, and orientation of design slopes. Fill slopes, when properly constructed with onsite materials, are expected to be grossly stable as designed. Cut slopes, If proposed, shoLjid be observed by the Project Geotechnical Consultant during grading, jf unsuitable soils are exposed, replacement with a stabilization fill may be required. 6.3 Storm Water Infiltration Systems Based on a review ofthe Preliminary SWMP plan (Alta, 2013), the proposed storm water mitigation systejms onsite will consist primarily of flow through planters connected to a stort|n drain system. Based on a review ofthe detail sheets, the flow through plarjiters do not allow infiltration of storm water into the underlying soils, and as spch, should not affect the geotechnical conditions onsite. Utilization of these systems is feasible from a geotechnical perspective, provided the unsuitable soil Recommendations presented iherein are I accomplished for the proposjsd improvements. ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 25 7.0 DESIGN CONSIDERATIONS 7.1 Structural Design It is anticipated that one to tyvo-story, wood-frame and masonry construction with slab on-grade and shallow foundations will be constructed. Upon the i completion of rough grading,^ finish grade samples should be collected and tested in orderto provide specific recommendations as they relate to individual building pads. These test results and |corresponding design recommendations should be presented in a final rough grading report. Final slab and foundation design recommendations should be made based upon specific structure sitings, loading conditions, and as-graded soil conditions. It is anticipated that the majority of onsite soils will possess "very low" to "low" expansion potential when tested in general accordance with ASTM Test Method D: 4829. For budgeting purposes, the following foundation design requirements for a range of potential expar)sion characteristics are presented. 7.1.1 Foundations Foundations may be preliminary designed based on the values presented in Table 7-1 below. I Table 7-1 Foitindation Design Parameters'* Allowable Bearing 2(|)00 lbs/ft' Lateral Bearing 2!pO lbs/ft^ at a depth of 12 inches plus 250 lbs/ft^ for each additional 12 inches of embedment to a maximum of 2000 lb<;/ft^ Sliding Coefficient 0.130 Differential Settlement Dynamic Differential = 1/2 inch in 40 feet Sljatic Differential = 3/4 inch in 40 feet *These values may be increased a^ allowed by Code to resist transient loads such as wind or seismic. Building code and structural design considerations may govern depth and reinforcement requirements and should be evaluated. ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 26 7.1.2 Post-Tensioned Slab^/Foundation Design Recommendations I Post-tensioned slabslfor the project may be preliminarily designed utilizing the parameters presented in Tables 7-1 and 7-2. The parameters 1 presented herein ar^ based on methodology provided In the Design of I Post-Tensioned Slab^-Qn-Ground, Third Edition, by the Post-Tensioning Institute, in accordance with the 2010 CBC. — TABLE 7-2 ~~ POST-TENSION SLAB DESIGN PARAMETERS Category 1 IA Expansion Potential Very Low LOW Minimum Embedment* 12 Inches 12 inches Em (ft) 5.7 Edge Lift Ym (inch) 0.24 0.61 Em (ft) 9.0 9.0 Center Lift Ym (inch) 0.11 0.26 Categories I and IA Sl^b Subgrade Moisture Minirhum 110% of optimum moisture to a depth of 12 inches prior to pouring concrete Embedment* The minimum footing embedments presented herein are based on expansion indexes. The structural engineer should determine minimum embedments based on the number of floors supported by the footings, the structural loading, and the requirements of the latesjt California Building Code. If mat slabs are utilized, alternate embedment depths can be provided. Moisture Barrier A moisture barrier should be provided in accordance with the recommendations presented in Section 7.2 The parameters presented herein are based o/ji procedures presented in the Desian of Post-Tensioned Slabs-On- Ground, Third Edition. No corrections for verticpl barriers at the edge of the slab, or for adjacent vegetation have been assumed. The design parameters are based on a Constant Suction Value of 3.9 pF. 7.1.3 Conventional Foundation Systems Based on the onsite soils conditions and information supplied by the CBC 2010, conventional fjjundation systems may be designed in accordance with Tables 7-1 and 7-3. ALTA CALiFOf^NiA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 27 r i TABLE 7-3 CONVENTIONALIFOUNDATION DESIGN PARAMETERS Expansion Potential Soil Category Design Plasticity Index Minimum Footing Embedment Very Low I 12 inches* Low 10 12 Inches* *The minimum footing embedments presented herein are based on expansion indexes. The structural engineer should determine minimum embedments based on the number of floors supported by the footings, the structural loading, an^ the requirements ofthe latest California Building Code. Minimum Footing Width 12finches-The structural engineer should determine the minimum fo(|)ting width based on loading and the latest California Building Code. Footing Reinforcement Nc|. 4 rebar, one (1) on top, one 1 (1) on bottom No. 4 rebar, one (1) on top, one (1) on bottom Slab Thickness 4 inches (actuai) 4 inches (actual) Slab Reinforcement Nd 3 rebar spaced 18 inches on center, each way No. 3 rebar spaced 18 inches on center, each way Under-Slab Requirement See Section 7.2 See Section 7.2 Slab Subgrade Moisture IMinimum of 110 percent of optimum moisture to a depth (jf 12 inches prior to placing concrete. Minimum of 110 percent of optimum moisture to a depth of 12 inches prior to placing concrete. Footing Embedment Adjacent to Swales and Slopes If Exterior footings adjacent to drainage swales are to exist within I five (5) feet horizontally of the swale, the footing should be ^mbedded sufficiently to assure embedment below the swale bottom is maintained. Footings adjacent to slopes should be erjibedded such that at least five- (5) feet is provided horizontally from edge of the footing to the face of the slope. Garages AgJ-ade beam reinforced continuously with the garage footings shajll be constructed across the garage entrance, tying together the ends ofthe perimeter footings and between individual spread footings. This grade beam should be embedded at the same depth as ^he adjacent perimeter footings. A thickened slab, separated by a c<j)ld joint from the garage beam, should be provided at the garage entrance. Minimum dimensions of the thickened edge shall be six (6) inches deep. Footing depth, width and reiriforcement should be the same as the structure. Slab thickness, reinforcement and under-slab treatment should be the sanlieas the structure. 7.2 Moisture Barrier A moisture and vapor retardijng system should be placed below the slabs-on- grade in portions ofthe structure considered to be moisture sensitive and should ALTA CALIFORRIIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 28 7.3 7.4 be capable of effectively preventing the migration of water and reducing the transmission of water vaporjto acceptable levels. Historically, a 10-mil plastic membrane, such as Visqueen, placed between one to four inches of clean sand, has been used for this purpcjse. The use ofthis system or other systems can be j considered, at the discretion ofthe designer, provided the system reduces the vapor transmission rates to Acceptable levels. Seismic Design The following seismic design parameters are presented to be code compliant to the California Building Code (jzOlO). The site has been identified as "D" site class in accordance with CBC, 201Cj, Table 1613.5.3 (1). Utilizing this information, the computer program USGS Earthquake Ground Motion Parameters Version 5.1.0 and ASCE 7 criterion, the spe^:tral response accelerations are as follows. Table 7-3 1 Seismic Design Parameters Latitude 33.165° N and Longitude -117.335° W Ss (period 0.2 sec) 1.265 SMs (period 0.2 sec) 1.265 SDs (period 0.2 sec) 0.843 Sl (period 1.0 sec) 0.477 SMI (period 1.0 sec) 0.727 SDl (period 1.0 sec) 0.485 These parameters should be i/erified bythe structural engineer. Additional parameters should be detemiined by the structural engineer based on the Occupancy Category ofthe pifoposed structures. Retaining Wall Design Retaining walls should be foiijnded on compacted fill and should be backfilled with select granular soils that allow for drainage behind the wall. Foundations may be designed in accordance with the recommendations presented in Table 7- 1, above. Unrestrained walli, free to rotate at least 0.001 radians, may be ALTA CALIFOI^NIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 29 designed to resist lateral pressures imposed by a fluid with a unit weight I determined in accordance v\jfith the Table 7-4 below. The table also presents design parameters for restrained (at-rest) retaining walls. These parameters may be used to design retaiijiing walls that may be considered as restrained due to the method of constructi({)n or location (corner sections of unrestrained retaining walls). TABLE 7 Equivalent Fluid Pressures for S {0= 32 -4 elect 90% Compacted Fill Backfill Active (psf/ft) At-Rest (psf/ft) Level 38 59 2:1 59 106 Per the requirements of the jCBC, the seismic force acting on the retaining walls with backfill exceeding 6-feejt in height may be resolved utilizing the formula 16H^ lb/lineal ft {H=height of| the wall). This force acts at approximately 0.67H above the base ofthe wall (ijiverted triangle). The seismic value can be converted as required by th^ retaining wall engineer. Retaining walls should be designed in general accordance with Section 1807A.2 ofthe 2010 CBC. > Restrained retaining wal|s should be designed for "at-rest" conditions. > The design loads presented in the above table are to be applied on the retaining wall in a horizohtal fashion and as such friction between wall and retained soils should not be allowed in the retaining wall analyses. > Additional allowances shpuld be made in the retaining wall design to account forthe influence of construction loads, temporary loads, and possible nearby structural footing loads. | > Select backfill should be granular, structural quality backfill with a Sand Equivalent of 20 or better and an ASCE Expansion Index of 20 or less. The backfill must encompass the full active wedge area. The upper one foot of backfill should be comprised of native on-site soils (see Plate A). ALTA CALIFOR|NIA GEOTECHNICAL, INC. RETAINING WALL BACKFII I DETAIL PROVIDE DRAINAGE SWALE *0R AS MODIFIED BY A SPECIFIC REPORT DRAIN UVTERALLY. OR PROVIDE WEEP HOLES AS REQUIRED TO DRAIN o PIPE: 4-INCH PERFORATED PVC, SCHEDULE 40, SDR35 OR APPROVED ALTERNATE MINIMUM 8 PERFORATIONS (1/4-IN. DIA.) PER LINEAL FT. IN BOTTOM HALF OF PIPE ROCK: MINIMUM VOLUME OF 1 CU. FT. OF 3/4-IN. MAX. ROCK PER. LINEAL FOOT OF PIPE, OR APPROVED ALTERNATE FILTER FABRIC: MIRAFI 140 FILTER FABRIC OR APPROVED EQUIVALENT AC^^L)''^\ ALTA CALIFORNIA GEOTECHNICAL, INC . ^ VER. 1/10 PLATEA PATH:\\LS-WTGL96E\shara\Alta Colifornia GBot«chnle(il\DraftIng\6RA0ING DETAILS\PLATE A.dwg Project No. 2-0068 Page 30 October 24, 2013 > The wall design should iiliclude waterproofing (where appropriate) and backdrains or weep holes for relieving possible hydrostatic pressures. The backdrain should be conjiprised of a 4-inch perforated PVC pipe in a 1 ft. by 1 ft., %-inch gravel matrix,|wrapped with a geofabric. The backdrain should be installed with a minimurfi gradient of 2 percent and should be outletted to an appropriate location. Fojr subterranean walls this may include drainage by sump pumps. > No backfill should be placed against concrete until minimum design strengths are achieved in compression tests of cylinders. It should be noted that the bearing values presented in Table 7-1 are based on level conditions at the toe. Modified design parameters can be presented for retaining walls with descendi|ig slope conditions at the toe. Other conditions I should be evaluated on a casfe by case basis. 7.5 Fence and Garden Walls Block walls, if used, should b^ embedded a minimum of 2 feet below the lowest adjacent grade. In the vicinit^ of descending slopes, the foundations should be embedded to provide for a minimum distance of H/6 (where H is the height of the slope) from the face ofthe slope to the outside edge ofthe bottom ofthe footing (to a maximum of 20 feet). Construction joints (not mor^ than 20 feet apart) should be included in the block wall construction. Side yard \|valls should be structurally separated from the rear yard wall. 7.6 Footing Excavations Soils from the footing excavations should not be placed in slab-on-grade areas unless properly compacted ai^d tested. The excavations should be cleaned of all loose/sloughed materials and be neatly trimmed at the time of concrete placement. Footing excavatidns should be observed by the Project Geotechnical ALTA CALIFOI^NIA GEOTECHNICAL, INC. Project No. 2-0068 Page 31 October 24, 2013 I Consultant prior to the placejnent of concrete to determine that the excavations are founded in suitable mate[-ial. j 7.7 Exterior Slabs and Walkwavsj Exterior concrete slabs and v\^alkways should be designed and constructed in I consideration ofthe following recommendations. 7.7.1 Subgrade Compaction The subgrade below pterior concrete slabs should be compacted to a minimum of 90 perc<int relative compaction as determined by ASTM Test Method: D 1557. 7.7.2 Subgrade Moisture The subgrade below poncrete slabs should be moisture conditioned to a minimum of 110 percent of optimum moisture content (low expansion) prior to concrete placement. 7.7.3 Concrete Slab Thickness Concrete flatwork and driveways should be designed utilizing four-inch minimum thickness. 7.7.4 Concrete Slab Reinforcement Utilization of reinforcement for flatwork and driveways is subject to a cost/benefit analysis] Reinforcement will decrease the amount of cracking that may ocj:ur in flatwork, however, planning for occasional repairs may be more cost effective. Utilizing closely spaced control joints maybe more cost-effective than utilizing reinforcement for low to very low expansive soils. Consideration should be given to reinforcing all flatwork with irregular (non-square/rectangular) shapes. ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 32 7.7.5 Control Joints Weakened plane joii^ts should be Installed on walkways at Intervals of approximately eight feet (maximum) or less. Exterior slabs should be designed to withstarjd shrinkage ofthe concrete. 7.8 Concrete Design As stated in Section 5.1.7, negligible concentrations of sulfates were detected in the onsite soils. Therefore, fhe use of sulfate resistant concrete Is not required per ACI 318-08 based on preliminary testing. Post-grading conditions should be evaluated and final recommendations concerning concrete design should be made at that time. 7.9 Corrosion Based on preliminary testing, the onsite soils may be mildly corrosive to buried metal objects (Romanoff, 1989). Consideration should be given to protecting burled metals from corrosioi. Typical measures Include using non-corrosive backfill, protective coatings, wrapping, or a combination of these methods in accordance with the manufacturer's recommendations. A corrosion engineer should be consulted if specific recommendations are required. Post-grading j conditions should be evaluated and final recommendations concerning corrosion should be made at that timej. 7.10 Pavement Design Pavement sections for the pj-oposed streets should be designed based on laboratory testing conducted on samples taken from the soil subgrade. Preliminarily, based on an as|sumed R-Value of 25 and a traffic index of 5.0, the streets may be designed util|zing a pavement section of 3-inches of asphalt over 6.5-inches of aggregate bas^. Alternately, if a temporary partial lift of A.C. is to be utilized and later capped after residential construction, a temporary section ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 33 of 3-inches AC and 6-inches ^B can be considered. This temporary section Is likely to provide improved performance under heavy construction loads and can then be capped with a l-incli layer. These sections should be verified upon the completion of grading, based on R-Value testing. Construction ofthe streets should be accomplished in accordance with the current criteria of the City of Carlsbad and under the observation and testing of the Project Geotechnical Cojisultant. i Prior to the placement of ba^e material, the subgrade should be suitably moisture conditioned, processed and compacted to a minimum 95 percent of the laboratory maximum dejisity (ASTM: D 1557) to at least twelve (12) Inches below subgrade. After subgj-ade compaction, the exposed grade should then be "proof-rolled with heavy ecjuipment to ensure the grade does not "pump" and is verified as non-yielding, /^ggregate base material should be placed on the compacted subgrade and compacted in-place to a minimum 95 percent ofthe laboratory standard obtaine|i per ASTM: D 1557. 7.11 Site Drainage Positive drainage away from the proposed structures should be provided and maintained. Roof, pad and Idt drainage should be collected and directed away from the structures toward Approved disposal areas through drainage terraces, gutters, down drains, and ot ler devices. Design fine grade elevations should be maintained through the life ofthe structure or if design fine grade elevations are altered, adequate area drainp should be installed in orderto provide rapid discharge of water, away from structures. Residents or Homeowner Associations should be made aware that they are responsible for maintenance and cleaning of all drainage terraces, dowji drains, and other devices that have been installed to promote site and structur^ drainage. ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 34 7.12 Deepened Footings and Setbacks It is generally recognized that improvements constructed In proximity to properly constructed slopes can, over a period of time, be affected by natural processes including gravity forces, weathering of surficial soils and long term (secondary) settlement. Mcjst building codes. Including the California Building Code (CBC), require that strijjctures be set back or footings deepened, where subject to the influence of tjiese natural processes. For the subject site, where foundations for residential sjtructures are to exist in proximity to slopes, the footings should be embedded to satisfy the requirements presented in the following figure. H/2 when H < 30 feet, need not exceed 10 feet, but not less tlian 5 feel. H/3 when H >30 feet, need not exceed 40 feet. H/2, need not be more than 15 feet Consideration of these natural processes should be undertaken in the design and construction of other improvements. Homeowners are advised to consult with qualified geotechnical engineers, designers, and contractors in the design and I construction of future improv^ements. Each lot and proposed improvement [ should be evaluated in relatic^n to the specific site conditions. ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 35 8.0 FUTURE PLAN REVIEWS This report represents a geotechr|ical review ofthe Tentative Tract Map. As the I project design progresses, site specific geologic and geotechnical issues should be considered in the design and construction ofthe project. Consequently, future plan reviews may be necessary. Thes^ reviews may include reviews of: > Grading Plans > Environmental Remediationj Plans for Soils > Foundation Plans > Utility Plans These plans should be forwarded ^o the project Geotechnical Consultant for review. 9.0 CLOSURE 9.1 Geotechnical Review For the purposes ofthis report, multiple working hypotheses were established for the project, utilizing the available data and the most probable model Is used for the analysis. Future information collected during the proposed grading operations is intended to evaluate the hypothesis and as such, some ofthe assumptions summarized in t;his report may need to be changed. Some modifications ofthe grading recommendations may become necessary, should the conditions encountered in the field differ from the conditions hypothesized in this report. Plans and sections ofthe evaluate conformance with report. If the project descrlpti herein, Alta must be consu recommendations contained project specifications should be reviewed by Alta, to e Intent ofthe recommendations contained in this ion or final design varies from that described in regarding the applicability of the herein and whether any changes are required. Alta th Ited ALTA CALIFORKIIA GEOTECHNICAL, INC. Project No. 2-0068 pggg gg October 24, 2013 accepts no liability for any use of its recommendations ifthe project description or final design varies and Alta is not consulted regarding the alterations. 9.2 Limitations This report is based on the fallowing: 1) the project as presented on the attached plan; 2) the information obtained from the subsurface investigation at the approximate locations indicated on the plan included herein; 3) laboratory test results; and 4) from the inforhnation presented in the referenced reports. The findings and recommendatiofis are based on the results ofthe subsurface investigation, laboratory testjng, and office analysis combined with an interpolation and extrapolatijan of conditions between and beyond the subsurface excavation locations. However, the materials adjacent to or beneath those observed may have differentjcharacteristics than those observed and no precise representations are made as ^:o the quality or extent of the materials not i observed. The findings are also based on information from previous investigations/geotechnical reports contained in the references. The results reflect an interpretation ofthe direct evidence obtained. Work performed by Alta has been conducted in a manner consistent with the level of care and skill ordinarily exercised by members ofthe geotechnical profession currently practicing in the same locality under similar conditions. No other representation, either expressed or implied, ^nd no warranty or guarantee is included or intended. The recommendations presented in this report are based on the assumption that i an appropriate level of field review will be provided by a geotechnical consultant who is familiar with the desigp and site geologic conditions. That field review shall be sufficient to confirm Ifhat geotechnical and geologic conditions exposed ALTA CALiF0Rf«iiA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page 37 during grading are consistenl: with the geologic representations and corresponding recommendations presented in this report. The conclusions and recommendations included in this report are applicable to the specific design ofthis prdject as discussed in this report. They have no applicability to any other project or to any other location and any and all subsequent users accept any and all liability resulting from any use or reuse ofthe data, opinions, and recommendations without the prior written consent of Alta. Alta has no responsibility for construction means, methods, techniques, sequences, procedures, safety precautions, programs In connection with the construction, acts or omlssiojis ofthe CONTRACTOR or any other person performing any of the construction, or for the failure of any of them to carry out the construction in accordan(|:e with the final design drawings and specifications. ALTA CALIFORNIA GEOTECHNICAL, INC. A|>PENDIXA i REFERENCES ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 Page A-1 October 24, 2013 APPENDIX A Sele<|ted References Alta California Geotechnical, Inc., 2013, Ge[)technical Review of SWMP Plan and Flow through Planters, Proposed Valley and Oak Development, City of Carlsbad, California, dated July 16 2013 (Project Number 2-0068). ; Alta California Geotechnical, Inc., 2012, Preliminary Geotechnical Investigation, Proposed Valley and Oak Development, City of Carlsbadi California, dated May 17, 2012 (Project Number 2- 0068). California Division of Mines and Geology, 2p08, Guidelines for evaluating and mitigating seismic hazards in California: Department of Conservation, Special Publication 117a. i CalTrans, 2003, Corrosion Guidelines, Calif<|rnia Department ofTransportation Division of Engineering Services Materials Engineering and Testing Services Corrosion Technology Branch, Version 1.0, September 2003. Gregg Drilling and Testing, Inc., 2000, Groundwater Depth Table, Southern California, Carlsbad March 8, 2000. I Hart, E. W., 1994, Fault-rupture hazard zon^s in California: California Division of Mines and Geology, special publication 42,1992 revised edition, 34 p. Jennings, C. W., 1994, Fault activity map of California and adjacent areas: California Division of Mines and Geology, California geologic map data series, map no. 6, scale 1:750,000. Jennings, C. W., 1985, An explanatory text to accompany the 1:750,000 scale fault and geologic map of California: California Division ofi Mines and Geology, special publication 42 revised 1985, 24 p. Kennedy, M.P. and Tan, S.S., 2005, Geologij Map ofthe Oceanside 30' x 60' Quadrangle, California: California Geologic Survey, Regional Geologic Map Series, 1:100,000 Scale, Map No. 3 Sheet land 2 of 2. Romanoff, Melvin, 1989, Underground Corrosion, NBS Circular 579, Reprinted by NACE Houston, TX, 1989. Stantec, Phase II Environmental Site Assessment, Vacant Lot, Southwest Corner of Valley Street and Oak Avenue, Carlsbad, California, 92008, March 30, 2012. Stantec, Phase I Environmental Assessment! Vacant Lot Southwest Corner of Valley Street and Oak Avenue, Carlsbad, California, 92008|, January 31, 2012. ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page A-2 , 2009, Tsunami Inundation Map for Emergency San Diego, Oceanside Quadrangle, San Luis Rey State of California, Department of Conservation, Planning, State of California, County of: Quadrangle, dated June 1, 2009. http://www.conservation.ca.gov/cgs/gleologic_hazards/Tsunami/lnundation_Maps/SanDieg o/Pages/SanDlego.aspx. Tan, S.S. and Kennedy, M.P., 1996, Geologic Maps ofthe Northwestern Part of San Diego County, California: California Geologic Survey, Regional Geologic Map Series, Plate 1. Tan, S.S. and Giffen, G.G., 1995, Landslide Hazards in the Northern Part ofthe San Diego Metropolitan area, San Diego County, California: California Division of Mines and Geology Open File-Report 95-04. United States, Dept. of Agriculture, 1953, Black and white, vertical air photos. Photo Nos. AXN- 14M-19, -20 & -21, flown May 2,1953, scale: 1:20,000. Weber, F.H., 1982, Recent Slope Failures, /^nclent Landslides, and Related Geology ofthe North- Central Coastal Area, San Diego County, California: California Division of Mines and Geology Open-File Report 82-12 LA. ALTA CALIFORNIA GEOTECHNICAL, INC. APPENDIX B Previous Sulssurface Investigation ALTA CALiFORijiiA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page B-l APPENDIX B Previous Subsurface Investigation Alta's previous subsurface investigation consisted of excavating, logging, and sampling three (3) hollow-stem auger borings and two hand auger excavations. Details ofthe subsurface investigation are presented in Table B-l. The approximate locations ofthe exploratory excavations are shown on the accompanying site plan (Figure 1). TABLE B-l SUBSURFACE INVESTIGATION DETAILS Equipment Range of Depths Sampling Methods Sample Locations Hollow Stem Auger Borings 13 to 17 feet 1. Bulk 2. Ring Sampler 1. Bulk-Select Depths 2. Ring-Select Depths Hand Auger 1.5 to 2 feet None None ALTA CALIFORNIA GEOTECHNICAL, INC. UNIFIED SOIL CLASSIFICATION SYSTEM Major Divisions grf ltr Coarse Grained Soils More than 50% retained on No. 200 sieve Gravel and Gravelly Soils More than 50% of coarse fraction retained on No. 4 sieve icw Sand and Sandy Soils More than 50% of coarse fraction passes No. 4 sieve GP Description Well-graded eravels or gravel sand mixtures, little or no fines Poorly-graded gravels or gravel sand mixture, little or no nnes Silty gravels, gravel-sand-silt GIVl mixtures GC SW SP SM SC Clayey gravels, gravel-sand-clay mixtures Well-graded sands or gravelly sands, little or no fines Poorly-graded sands or gravelly sands, little or no fines i Silty sands, sand-silt mixtures Clayey sunds, and-clay mixtures Major Divisions grf ltr Fine Grained Soils More than 50% passes No. 200 sieve Silts And Clays LL<50 Silts And Clays LL>50 Highly Organic Soils Inorganic silts and very fine sands, [ynJ rock flour, silty or clayey fine sands ^ or clayey silts with slight plasticity OH Description Inorganic clays of iov to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays Organic silts and organic silt-clays of low plasticity Inorganic silts, micaceous or diatomaceous fine or silty soils, elastic silts Inorganic clays of high plasticity, fat cwys Organic clays of medium to high plasticity Feat and other highly organic soils BOUNDARY CLASSIFICATIONS: Soils possessuig characteristics of two groups are designated by combinations of group symbols. PARTICLE SIZE LIMITS 200 U.S. STANDAKD SERIES SIEVE 40 10 CLEAR SQUARE SIEVE OPENINGS 3/4" 3" 12" Silts and Clays - Sand Gravel Cobbles Boulders Silts and Clays - Fine Medium Coarse Fine Coarse Cobbles Boulders RELATIVE DENSITY CONSISTENCY CLASSIFiCATION HARDNESS Sands and Gravels Blows/Foot (SPT) Very Loose <4 Loose 4-10 Medium Dense 11-30 Dense 31 - 50 Very Dense >50 Sjilts and Clays Criteria Very Soft Thumb penetrates soil >1 in. Soft Thumb penetrates soil 1 in. Firm Thumb penetrates soil 1/4 in. Stiff Readily indented with thumbnail Very Stiff Thumbnail will not indent soil Bedrock Soft Moderately Hard Hard Very Hard LABORATORY TESTS Symbol Test DS Oirect Shear DSR Direct Shear (Remolded) CON Consolidation SA Sieve Analysis MAX Maximum Density RV Resistance (R) Value EI Expansion Index SE Sand Equivalent AL Atterberg Limits CHEM Chemical Analysis HY Hydrometer Analysis SOIL MOISTURE Increasing Visual Moisture CoDtent Dry - Dry to touch Moist - Damp, but no visible free water Wet - Visible free water SIZE PROPORTIONS Trace - < 5 % Few-5 to 10% Some -15 to 25 % KEY TO EXPLORATORY BORING LOGS ALTA CALIFORNIA GEOTUCNNICAL INC. PLATE B PROJECT NO. DATE STARTED DATE FINISHED DRILLER TTPE OF DRILL RIG 2-0068 GEOTECHNICAL BORING LOG SHEET 1 OF 1 5/2/12 5g/12 Pacific DrIIIInu Hollow Stem PROJECTNAME Vallev & Oak GROUND ELEV. igg GW DEPTH (FT) DRIVE WT. 140 Ibs DROP 30 In. BORING DESIG. LOGGED BY NOTE B-1 _EE_ mu. 5- 10- 15- UJ 165- Hi 160 155- OQ 6S 70 36 35 1 oi SM GEOTECHNICAL DESCRIPTION TOPSOIL: SI).TY SAND; strong brown, moist, loose, fin© grained. tii^ o aa OLD PARALIC DEPO.qiy.g fflnpv SILTY SANDSTONE; reddish brown, massive, moist, moderately clay cemented, dense, some manganese oxide. @ 4 ft. dark reddish brown, trace of coarse grained sand. @ 8 ft. dark reddish brown and reddish brown, moist. 6.1 8.7 11.5 @ 16 ft. fine to medium grained. TOTAL DEPTH = 17 FT. NO GROUNDWATER ENCOUNTERED 12.1 SAMPLE TYPES: CD RING (DRIVE) SAMPLE (a SPT (SPLIT SPOON) SAMPLE El BULK SAMPLE S] TUBE SAMPLE ^58 111 118 111 33 58 62 123 92 Ul h-X CO t- UJ O H MAX a, HY. CHEM DSR i GROUNDWATER • SEEPAGE J: JOINTING C: CONTACT B: BEDDING F: FAULT S: SHEAR RS: RUPTURE SURFACE Alta California Geotechnical, Inc. P.N. 2-0068 PL^TE B-1 PROJECT NO. DATE STARTED DATE FINISHED DRILLER TYPE OF DRILL RIG GEOTECHNICAL BORING LOG SHEET 1 OF 1 2-0068 5/2/12 5/2/12 Pacific Drilling Hollow Stem PROJECT N/\I\/IE Vallev & Oak GROUND ELEV. 162 ~ GW DEPTH (IFT) DRIVE WT. i DROP 140 Ibs BORING DESIG. LOGGED BY NOTE B-2 -EE. ?0 In. LUU. 10- 160 155 150' UJ ho. tn 2 m 50 37 35 52 oi SM § 12 ft. CLAYEY SANDSTONE; reddish brown, massive, moist, fine" -\to medium grained, clay cemented, some manganese oxide. /- TOTAL DEPTH = 13 FT. NO GROUNDWATER ENCOUNTERED GEOTECHNICAL DESCRIPTION TOPSOIL: SILTY SAND; strong brown, slightly moist, loose, fine grained. OLD PARALIC DEPOSIT? fQop): SILTY SANn.srnNF; light reddish brown, massive, slightly moist, dense, fine grained, weathered. @ 4 ft. dark reddish brown, clay cemented, some manganese oxide. 1 8 ft. moist. OT _ 2" 4.0 11.0 11.2 9.8 QTUJ Q a z 115 116 118 66 70 65 Ui H X W F UJ o • CON, HY SAMPLE TYPES: El RING (DRIVE) SAMPLE [a SPT (SPLIT SPOON) SAMPLE ca BULK SAMPLE OD TUBE SAMPLE I GROUNDWATER IKK- SEEPAGE J: JOINTING C: CONTACT B: BEDDING F: FAULT S: SHEAR RS: RUPTURE SURFACE Alta California Geotechnical, Inc. P.N. 2-0068 PLATE B-2 PROJECT NO. DATE STARTED DATE FINISHED DRILLER TYPE OF DRILL RIG GEOTECHljJICAL BORING LOG 2-0068 S/2/12 5/2/12 J£3_ Pacific Drilling Hollow Stem PROJECTNAME Valley & Oak GROUND EL5V. GW DEPTH (ff) DRIVE WT. ; 140 Ibs DROP ! 30 in. BORING DESIG. LOGGED BY NOTE SHEET 1 OF 1 B-3 x^ uju. 10 -I UJ 160- 155- UJ -Jill 9=0. 150 55 34 30 56 Ola SM SAMPLE TYPES: IS RING (DRIVE) SAMPLE El SPT (SPLIT SPOON) SAMPLE [B BULK SAMPLE W TUBE SAMPLE GEOTECHNICAL DESCRIPTION TOPSQIL: SILTY SAND; light yellow brown, slightly moist, loose, fine grained. OLD PARALIC DEPOSITS fQopV SII TY SANnSTONF; r»riHi«h brown, massiv^, slightly moist, weathered, dense, fine grained, trace of coarse grained sand, some clay. i @ 4 ft. very deijise, some manganese oxide. @ 8 ft. some g(ay brown fine grained, undulatofy sand deposits within reddish Idrown silty sandstone. ^3? t- I- wz OR ! 12 ft. clay cemented. TOTAL DEPTH = 13 FT. NO GROUNDWATER ENCOUNTERED 10.0 10.4 6.8 6.2 cc UJ Q a 3 I GROUNDWATER EI SEEPAGE! J: JOINTING CJ CONTACT B: BEDDING F:! FAULT S: SHEAR RS: RUPTURE SURFACE 122 110 102 115 75 55 29 37 a: V) Ul K I w o CON, HY Alta California Geotechnical, Inc. P.N. 2-0068 PLATE B-3 PROJECTNO. DATE STARTED DATE FINISHED DRILLER TYPE OF DRILL RIG 2-0068 5/23/12 GEOTECHNICAL BORING LOG Valley & Oak SHEET 1 OF 1 5/23/12 Hand Auoer PROJECT UfiME GROUND ELEV. GW DEPTH (IfT) DRIVE wr. DROP BORING DESIG. LOGGED BY NOTE B-4 _EE_ 2:0. ffi mm SM GEOTECHNICAL DESCRIPTION TOPSOIL SILTY SAND, light brown, dry, loose, fine grained, some clay. SAMPLE TYPES; (B RING (DRIVE) SAMPLE [S SPT (SPLIT SPOON) SAMPLE ca BULK SAMPLE ffl TUBE SAMPLE OLD PARALIC DEPpSff.? (Qop); CLAYEY SANDSTONE, light reddish brown, ^lightly moist, medium dense, fine to medium grained, moderately weathered. "S 2 ft. dense, $lightly weathered, reddish brown. i lOIAL UbPTH"2FT. ^ ' NO GROUNDWATER ENCOUNTERED oo 5" >-z S GROUNDVyATER ^ SEEPAGE! J: JOINTING C:| CONTACT B: BEDDING F:i FAULT S; SHEAR RS: RUPTURE SURFACE z 3 5g Alta California Geotechnical, Inc. P.N. 2-0068 PLATE B-4 PROJECT NO. DATE STARTED DATE FINISHED DRILLER TYPE OF DRILL RIG 2-0068 GEOTECHNICAL BORING LOG SHEET 1 OF 1 5/23/12 5/23/12 Hand Auoer PROJECTNAME Vallev & Oak GROUND ELEV. GW DEPTH (fT) DRIVE WT. DROP i BORING DESIG. LOGGED BY NOTE B-5 UJLL > UJ It 3 m Or; s V) SM GEOTECHNICAL DESCRIPTION TOPSOIL SILTY SAND, light brown, dry. loose, fine grained, some lij^ li i8 OLD PARALIC DEPOSITS (Qop): CLAYEY SANDSTONE, light reddish brown, slightly moist, medium dense, fine to medium grained, clay cemented. 1.5 ft. reddish brown, dense. *IUIALUtPrH»1.5FT. NO GROUNDWATER ENCOUNTERED •~'U) cc LU QQ CC to 5^ SAMPLE TYPES: ca RING (DRIVE) SAMPLE [S SPT (SPLIT SPOON) SAMPLE [11 BULK SAMPLE ffl TUBE SAMPLE Z GROUNDWATER SEEPAGE J: JOINTING C; CONTACT B: BEDDING F: FAULT S: SHEAR RS; RUPTURE SURFACE Alta California Geotechnical, Inc. P.N. 2-0068 PLATE B-5 APPENDIX C Laboratory Testing ALTA CALIFORNIA GEOTECHNICAL, INC. APPENDIX C Previous Laboratory Testing ALTA CALIFORNIA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 Page C-1 Previous LABORATORY TESTING The following laboratory tests were perfornr^ed the applicable latest standards or methods California Department ofTransportation. Classification Soils were classified with respect to the Uni With ASTM D-2487 and D-2488. on representative samples in accordance with rom the ASTM, California Building Code (CBC) and ied Soil Classification System (USCS) in accordance Particle Size Analvsis Modified hydrometer testing was conducted to aid in classification ofthe soils. The results of the particle size analysis are presented in T^ble C. Consolidation Tests Consolidation tests were performed on two (2) relatively "undisturbed" soil samples at their natural moisture content in accordance with procedures outlined in ASTM D-2435. Samples were placed in a consolidometer and loads were applied incrementally in geometric progression. The samples were permitted to consolidate under each load increment until the slope ofthe characteristic linear secondary compression portion ofthe thickness versus log of time plot was apparent. The percent consolidation for each load cycle was recorded as the ratio ofthe amount of vertical compression to the original 1-inch height. The consolidation test results are shown on Plates C-1 and C-2. Direct Shear Tests Direct shear testing was performed on one iample that was remolded to 90% of the maximum density. The maximum dry density and optimum moisture content of a selected representative ALTA CALIFORIIIA GEOTECHNICAL, INC. Project No. 2-0068 Page C-2 October 24, 2013 bulk sample was evaluated in accordance with ASTM D-1557. The results of this test is presented on Plate C-3. Maximum Density/Optimum Moisture The maximum dry density and optimum moisture content of one representative bulk sample was evaluated in accordance with ASTM D-1557. The results are summarized in Table C. Expansion Index Tests One (1) expansion index test was performed to evaluate the expansion potential of typical on- site soils. Testing was carried out in general conformance with ASTM Test Method D-4829. The results are presented in Table C. Chemical Analyses Chemical testing of selected samples was performed by Cal Land Engineering. The results of these tests are included presented on Plate C-4. ALTA CALIFORNIA GEOTECHNICAL, INC. TABLE C SUMMARY OF LABORATORY TEST DATA P.N. 2-0068 BORING I>EPTH (FEET) SOIL DESCRIPTION GROUP SYMBOL MAXIMUM DENsrrv (PCF) OPTIIMUM MOISTURE CONTENT (%) DIRECT SHEAR PLUS NO.4 SBVE (plus 4.76nim) (%) SANO {4.7SRiin-0.07Emm) (%) SILT [O.OTSmm-O.OOemm; (%) CLAY [minus O.OOSmm) {%) EXPANSION INDEX UBC 18-2 CONSOL OTHER TESTS REMARKS B-1 3 SIHy Sandstone (Qop) 134.0 8.0 SEE PLATE C-3 2 60 19 IS 0 Chemlul: Plate C.4 B-2 4 Sllty Sandstone (Qop) 1 5S IS 23 SEE PLATE C-1 B-3 s Sandstone (Qop) 0 83 E 11 SEE PLATE C-2 Alta California Geotechnical, Inc. COMPRESSIVE STRESS IN ISF 0.1 2 3 4 6678911 2 3 4 5 6 7 8 910 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.C 7.0 8.0 X LU X z m CD z < X o h-z LU o ct UJ Q. 4-: 1 ,—:. boring depth (ft.) dry density (pcf) In situ moisl. (%) in sliu satur. (%) 1 -200 4leve (%) group symbol lypical names B-2 4.0 115 110 65 44 Silty Sandstone (Qop) REMARKS: WATER ADDED AT 1.07 TSF CONSOLIDATION CURVE Alta Caiifornia Geotechnicai, Inc. P.N. 2-0068 PLATE C-1 COMPRESSIVE STRESS IN TSF 0.1 3 4 5 6 7 8 9 1 -2.0 -1.0 0.0 f 1.0 o UJ X Z 2.0 LU < 5 3.0 h-z LU O S 4.0 5.0 6.0 7.0 8.0 3 4 5 6 7 8910 — 1- boring depth (ft.) dry density {pcf) In situ moist. {%) In situ satur. (%) -200 sieve (%) group symbol typical names B-3 8.0 102 6.8 29 17 Sandstone (Qop) REMARKS: WATER ADDED AT 1.07 TSF CONSOLIDATION CURVE Alta California Geotechnical, Inc. P.N. 2-0068 PLATE C-2 GEOTEK DIRECT gHgARTEST Project Name,- Alta California Geotechnkal Project Number Soif Description.- ACG 2-0068 Somp/e Source: B-l@3' Date Terted: 5/22/1011 Oa 31.0' 0.20 ksf Final Water Final Dry Tejt No. Load (kiO Content {%) Density (pcf) 1 1.4 13.0 122.1 2 2.8 I2.B 121.6 S.6 110 121.8 Notes) I - The soil specimens sheared were remoldejl samples. The soli was remolded co 90X relative compaction at optimum moisture content 2 - The above reflect residual shear strength saturated conditions. 3 - The tests were run at a shear r^te of 0.02$ In/mln. PLATE C-3 mv-i8-2QlS 13:07 FromJ Totl951.71.01i67 P»«e!3-'3 Cal Land Engineering, Inc. dba Quart^ch Consultants Geotechnical, Environmental, and Civil EnQlneering For; GooTek, Inc. W.O.; 0S37 - CR3 Client: Alta Califomia Gsoteohnlcai Prajeol: 2-0068 PO#2684 Date: May 18.2012 QCI Project No,: 12.167.Q5h Summarized by: ABK CoiTOfilvlty Teat Reauilo ID Deptii (Feat) pH CT-632 (6«) Chloride Cr-422 (ppm) SulfiatB CT^417 (%By Welflht) Reslstivl^ CT-632 (643) (ohmncm) B-1 3.0 7.86 S6 0.0240 3.700 57(5 East Lambert Road. Braa. CBHfernla W821; Tel; 714-871-1060; Fax: 714-671-1000 PLATE C-4 APPENDIX D Earthworfk Spedfications ALTA CALIFORNIA GEOTECHNICAL, INC. ALTA CAUFORNIA GEOTECHNICAL, INC. EARTHWORK SPECIFICATIONS These specifications present tlie generally accepted standards and minimum eartiiwork requirements for the development of the project. These specifications shall be the project guidelines for earthwork except where specij'ically superceded in preliminary geology and soils reports, grading plan review reports or by th^ prevailing grading codes or ordinances of the controlling agency. Pi. GENERAL 1. The Contractor shall be responsible for the satisfactory completion of all earthwork in accordance with the project plans and specifications. 2. The project Geotechnical Engineer and Engineering Geologist, or their representatives, shall provide observation and testing services, and Geotechnical consultation for the duration ofthe project. 3. All clearing, grubbing, stripping and site preparation for the project shall be accomplished bythe Contractjor to the satisfaction ofthe Geotechnical Engineer/Engineering Geologjst. 4. It is the Contractor's responsibility to prepare the ground surface to receive fill to the satisfaction ofthe Geotechnical Engineer and to place, spread, mix, moisture condition, and compact the fill in accordance with the job specifications and as required by the Geotechnical Engineer. The Contractor shall aiso remove all material considered by the Geotechnical Engineer to be unsuitable for use in the construction of engineered fills. 5. The Contractor shall have suitable and sufficient equipment In operation to handle the amount of fill being placed. When necessary, equipment will be shut down temporarily in order to permit the proper preparation of fills. B. PREPARATION OF FiLL AREAS 1. Excessive vegetation and all deleterious material should be disposed of offsite as required bythe Geotechnica) Engineer. Existing fill, soil, alluvium or rock materials determined bythe Geotechnical Engineer as being unsuitable for placement in compacted fills shall be removed and hauled from the site. Where applicable, the Contractor may obtain the ALTA CALIFORNIA GEOTECHNICAL, INC. Earthwork Specifications Page 2 approval of the Soils Englneejr and the controlling authorities for the project to dispose ofthe above describfed materials, or a portion thereof, in designated areas onsite. After removal ofthe deleterious materials have been accomplished, earth materials deemed unsuitablelin their natural, in-place condition, shall be removed as recommended bythe Geotechnical Engineer/Engineering Geologist. 2. Upon achieving a suitable bottom for fill placement, the exposed removal bottom shall be disced or bla[Jed by the Contractor to the satisfaction ofthe Geotechnical Engineer. The prepared ground surfaces shall then be brought to the specified moisture content mixed as required, and compacted and tested as specified. In localities where it is necessary to obtain the approval ofthe controlling agency prior to placing fill, it will be the Contractor's responsibility to contact the proper authorities to visit the site. 3. Any underground structure such as cesspools, cisterns, mining shafts, tunnels, septic tanks, wells, pipelines or other structures nol located prior to grading are to be removed or treated in a manner prescribed by the Geotechnical Engineer and/or the controlling agency for the project. ENGINEERED FILLS 1. Any material imported or exdavated on the property may be utilized as fill, provided the material has been determined to be suitable by the Geotechnical Engineer. Deleterious materials shall be removed from the fill as directed by the Geotechnical Engineer. 2. Rock or rock fragments less than twelve inches in the largest dimension may be utilized in the fill, provided they are not placed in concentrated pockets and the distribution ofthe rocks is approved by the Geotechnical Engineer. 3. Rocks greater than twelve inches in the largest dimension shall be taken offsite, or placed in accordance with the recommendations ofthe Geotechnical Engineer in areas designated as suitable for rock disposal. j 4. All materials to be used as fill, shall be tested in the laboratory by the Geotechnical Engineer. Proposed import materials shall be approved bythe Geotechnical Engineer 48 hours prior to importation. 5. The fill materials shall be placed by the Contractor in lifts, that when compacted, shall not exceed six Inches. Each lift shall be spread evenly and shall be ALTA CALIFORNIA GEOTECHNICAL, INC. Earthwork Specifications Page 3 thoroughly mixed to achieve a near uniform moisture condition and a uniform blend of materials. All compaction shall be achieved at or above the optimum moisture content, as determined by the applicable laboratory standard. The Contractor will be notified ifthe fill materials ai"e too wet or too dry to achieve the required compaction standard. 6. When the moisture content of the fill material is below the limit specified by the Geotechnical Engineer, water shall be added and the materials shall be blended until a uniform moisture content, within specified limits, is achieved. When the moisture content ofthe fill material is above the limits specified bythe Geotechnical Engineer, the fill materials shall be aerated by discing, blading, mixed with dryer fill materials, or other satisfactory methods until the moisture content is within the specified limits. 7. Each fill lift shall be compacted to the minimum project standards, in compliance with the testing methods specified by the controlling governmental agency, and in accordance with recommendations of the Geotechnical Engineer. In the absence of specific recommendations bythe Geotechnical Engineer tothe contrary, the compaction standard shall be the most recent version of ASTI\/1:D 1557. 8. Where a slope receiving fill exceeds a ratio of five-horizontal to one-vertical, the fill shall be keyed and benched through all unsuitable materials into sound bedrock or firm material, in accordance with the recommendations and approval ofthe Geotechnical Engineer. 9. Side hill fills shall have a minimum kev width of 15 feet into bedrock or firm materials, unless otherwise specified in the soil report and approved by the Geotechnical Engineer in the field. 10. Drainage terraces and subdrainage devices shall be constructed in compliance with the ordinances ofthe controlling governmental agency and/or with the recommendations ofthe Geotechnical Engineer and Engineering Geologist. 11. The Contractor shall be required to maintain the specified minimum relative compaction out to the finish slope face of fill slopes, buttresses, and stabilization fills as directed by the Geotechnical Engineer and/or the governing agency for the project. This may be achieved by either overbuilding the slope and cutting ALTA CALIFORNIA GEOTECHNICAL, INC. Earthwork Specifications Page 4 back to the compacted core; by direct compaction ofthe slope face with suitable equipment; or by any other procedure which produces the required result. 12. The fill portion of fill-over-cut slopes shall be properly keyed into rock or firm material; and the fill area shajl be stripped of all soil or unsuitable materials prior to placing fill. The design cut portion ofthe slope should be made flrst and evaluated for suitability by the Engineering Geologist prior to placement of fill in the keyway above the cut slope. 13. Pad areas in cut or natural ground shall be approved by the Geotechnical Engineer. Finished surfaces of these pads may require scarification and recompaction, or over excavation as determined by the Geotechnical Engineer. D. CUT SLOPES 1. The Engineering Geologist shiill observe ali cut slopes and shall be notified by the Contractor when cut slopes are to be started. 2. If, during the course of grading, unforeseen adverse or potentially adverse geologic conditions are encountered, the Engineering Geologist and Soil Engineer shall investigate, analyze and make recommendations to remediate these problems. 3. Non-erodible interceptor swales shall be placed at the top of cut slopes that face the same direction as the sur^erjacent, prevailing drainage. 4. Unless otherwise specified in specific geotechnical reports, no cut slopes shall be excavated higher or steeper than that allowed by the ordinances of controlling governmental agencies. 5. Drainage terraces shall be constructed In compliance with the ordinances ofthe controlling governmental agencies, and/or in accordance with the recommendations ofthe Geotechnical Engineer or Engineering Geologist. E. GRADING CONTROL 1. Fill placement shall be observed and tested by the Geotechnical Engineer and/or his representative during grading. Field density tests shall be m^de bythe Geotechnical Engineer and/or his representative to evaluate the compaction and moisture compliance of each fill lift. Density tests shall be conducted at Intervals not to exceed two feet of fill ALTA CAUFORNIA GEOTECHNICAL, INC. Earthwork Specifications Page 5 height. Where sheepsfoot rollers are used, the fill may be disturbed to a depth of several inches. Density determinations shall be taken in the compacted material below the disturbed surface at a depth determined by the Geotechnical Engineer or his representative. 2. Where tests indicate that the density of any layer of fill, or portion thereof, is below the required relative compaction, or improper moisture content is in evidence, that particular layer or portion thereof shall be reworked until the required density and/or moisture content has been attained. Additional fills shall not be placed over an area until the previous lift of fill has been tested and found to meet the density and moisture requirements for the project and the previous lift is approved by the Geotechnical Engineer. 3. When grading activities are interrupted by heavy rains, fill operations shall not be resumed until field observations and tests bythe Geotechnical Engineer indicate the moisture content and density of the fill are within the specified limits. 4. During construction, the Contractor shall properly grade all surfaces to maintain good drainage and prevent the ponding of water. The Contractor shall take remedial action to control surface water and to prevent erosion of graded areas until such time as a permanent drainage and erosion devices have been installed. 5. Observation and testing by the Geotechnical Engmeer and/or his representative shall be conducted during filling and compacting operations in order that he will be able to state in his opinion that all cut and filled areas are graded in accordance with the approved specifications. 6. Upon the completion of grading activities and after the Geotechnical Engineer and Engineering Geologist h^ve finished their observations of the work, final reports shall be submitted. No further excavation or fill placement shall be undertaken without prior notification ofthe Geotechnical Engineer and/or Engineering Geologist. FINISHED SLOPES All finished cut and fill slopes shall be planted and irrigated and/or protected from erosion in accordance with the project specifications, governing agencies, and/or as recommended by a landscape architect. ALTA CALIFORNIA GEOTECHNICAL, INC. APPENDIX E I ! Grading Details ALTA CALiFORtiiiA GEOTECHNICAL, INC. DETAIL FOR FILL SLOPE TOEING OUT ON FLAT ALLUVIATED CANYON PROPOSED FILL SLOPE PRE-EXISTING SURFACE TO BE RESTORED WITH COMPACTED FILL TOE OF SLOPE AS SHOWN ON GRADING PU\N ALLUVIUM TO REMAIN IN PUCE ANTICIPATED ALLUVIAL REMOVAL DEPTH PER GEOTECHNICAL-EMGINEEB- / FORECUT VARIES; FOR DEEP REMOVALS, FORECUT SHOULD BE MADE NO STEEPER THAN 1:1, OR AS REQUIRED FOR SAFETY CONSIDERATIONS ALTA CALIFORNIA GEOTECHNICAL, INC VER. 3/12 APPROVED COMPETENT MATERIAL PROVIDE A 1:1 MIN. PROJECTION FROM TOE OF SLOPE AS SHOWN ON GRADING PU\N TO THE RECOMMENDED REMOVAL BOTTOM. SLOPE HEIGHT, SITE CONDITIONS, AND/OR LOCAL CONDITIONS COULD DICTATE PUTTER PROJECTIONS PLATE G-1 PATHi\\LS-WTGL96E\share\Al-to California Geo-technlcalNDraftingXGRADING DETAILSXG-Ldwg REMOVAL ADJACENT TO EXISTING FILL PROPOSED FINISH GRADE INTERIM GRADE TEMPORARr ENGINEERED FILL ALLUVIUM (TO BE REMOVED AND REPLACED WITH ENGINEERED FILL) ^APPROVED-' COMPETENT MATERIAL ^INITIATE l:l TIE-IN BACKCUT TO INTERCEPT TOE OF INTERIM BACKCUT **AS PART OF TIE-IN FOR ADDITIONAL ENGINEERED FILL ALTA CALIFORNIA GEOTECHNICAL, INC . VER. 3/12 PLATE G-2 PATHi\\LS-VTGL96E\share\Alta Colifornia Geotechnlcal\Draf-ting\GRADING DETAILSNG-S.dwg CANYON SUBDRAIN PRE-EXISTING TOPOGRAPHY APPROVED REMOVAL BOTTOM TYPICAL BENCHING DURING FILL PLACEMENT •Sz'''°/I':f/Sj-i''/li."i' APPROVED COMPETENT MATERIAL SEE DETAIL (PLATE G-4) ALTA CALIFORNIA GEOTECHNICAL, INC VER. 3/12 PLATE G-3 PATH;\\LS-WTGL96E\thar«\Alta California 0•o••chnlea^D^aftlnfl\ORAOING DETAILS\G-3.dwg CANYON SUBDRAIN DETAIL 6" MIN. OVERLAP FILTER FABRIC 6" MIN ROCK PERFORATED PIPE SURROUNDED WITH ROCK AND FILTER FABRIC ROCK; MIN. VOLUME OF 9 CU.FT. PER UNEAR FT. OF 3/4 IN. MAX. ROCK PIPE: 6 IN. ABS OR PVC PIPE WITH A MINIMUM OF 8 PERFORATIONS (1/4-IN. DIA.) PER lllNEAL FT. IN BOTTOM HALF OF PIPE ASTM D2751, SDR 35, OR ASTM D3034 OR ASTM D1527, SCHD. 40 ASTM 01 785, SCHD. 40 FILTER FABRIC: MIRAFI 140 FILTER FABRIC OR APPROVED EQUIVALENT NOTE: FOR CONTINUOUS RUN IN EXCESS OF 500. FT USE 8 IN. DIA. PIPE ALTA CALIFORNIA GEOTECHNICAL, INC . VER. 3/12 PLATE G-4 PATH:\\LS-WTGL96E\shar«\Alta California 0•otechnlca^Draf4lng\GRADIN6 DETAILS\G-4.dwg OVEREXCAVATION CUT LOT EXISTING TOPOGRAPHY OVEREXCAVATE AND REPLACE WITH ENGINEERED FILL APPROVED COMPETENT MATERIAL CUT-FILL LOT (TRANSITION) EXISTING TOPOGRAPHY MIN. OVEREXCAVATE AND RECOMPACT APPROVED COMPETENT MATERIAL UNSUITABLE MATERIAL TO BE REMOVED AND REPLACED WITH ENGINEERED FILL *NOTE ALL BUILDING PADSISHALL BE OVER EXCAVATED TO A MINIMUM OF Yz OF T^E MAXIMUM DEPTH OF FILL BELOW THE BUILDING PAD TO A MAXIMUM OF 17 FEET (SEE PLATE G-16) ^ ALTA CALIFORNIA GEOTECHNICAL, INC VER. 3/12 PLATE G-5 PATHA\l-S-VTGL96E\shor«\Al-la Colifornia G«o-t«chnlcol\Drof-ting\GRADING LETAILS\G-5.dwg SIDE HILL SLOPE FILL DETAIL (NATURAL SLOPES 5:1 OR STEEPER) EXISTING TOPOGRAPHY PROPOSED GRADE COMPACTED FILL MAINTAIN MIN. 15' HORIZ. WIDTH FROM FACE OF SLOPE TO BENCH/BACKCUT TOE OF SLOPE ON PROVIDE A l:l MINIMUM GRADING PLAN PROJECTION FROM DESIGN TOE OF SLOPE TO TOE OF KEY NATURAL SLOPE TO BE RESTORED WITH COMPACTED FILL FORECUT VARIES 2' MIN. INTO APPROVED COMPETENT MATERIAL WIDTH VARIES NOTES MIN. KEY DIMENSION 15'X2'X3' ALTA CALIFORNIA GEOTECHNICAL, INC VER. 3/12 1. WHERE NATURAL SLOPE GRADIENT IS 5:1 OR LESS, SEE PLATE 6-1. WHERE THE NATURAL SLOPE APPROACHES OR EXCEEDS THE DESIGN SLOPE RATIO, SPECIAL RECOMMENDATIONS WILL BE PROVIDED BY THE GEOTECHNICAL ENGINEER. 2. THE NEED FOR AND PLACEMENT OF DRAINS WILL BE DETERMINED BY THE GEOTECHNICAL ENGINEER OR GEOLOGIST BASED UPON EXPOSED FIELD CONDITIONS. PLATE G-6 PATH<N\LS-WTGL96E\share\At-l;o Californio Geoteciinical\Draftlng\GRADING DETAILS\G-6.clwg FiLL OVER CUT SLOPE DETAIL PROPOSED GRADE EXISTING TOPOGRAPHY *DESIGN CUT SLOPE APPROVED COMPETENT MATERIAL MiN. KEY 15'X2'X3' DIMENSION NEED AND LOCATION OF HEEL DRAIN TO BE DETERMINED BASED UPON FIELD CONDITIONS, SEE DETAIL PU\TE G-8 *THE CUT PORTION OF THE SLOPE SHOULD BE EXCAVATED AND EVALUATED BY THE ENGINEERING GEOLOGIST/GEOTECHNICAL ENGINEER PRIOR TO CONSTRUCTING THE FILL SLOPE ^Ly^\ ALTA CALIFORNIA GEOTECHNICAL, INC VER. 3/12 PLATE G-7 PATHi\\LS-VTGL96E\shore\Al-to Californio Geo^hnlcolXDroftlngXGRADING IIETAILS\G-7.clwg STABILIZATION/BUTTRESS FILL BACKDRAIN NOTE: 1 ASTM D2751, SDR 35, OR ASTM D3034 OR ASTM D1527, SCHD. 40 ASTM D1785, SCHD. 40 SOLID PIPE OUTLETS TO BE PROVIDED EVERY 100 FT. AND JOINED TO PERFORATED BACKDRAIN PIPE WITH "L" OR 'T"s. MIN. 2% GRADIENT. 3. GRAVEL TRENCH TO BE FILLED WITH 3/4 IN. M.AXIMUM ROCK 4. THE NECESSITY FOR UPPER TIER BACKDRAINS SHALL BE DETERMINED IN THE FIELD BYTHE GEOTECHNICAL ENGINEER OR GEOLOGIST. UPPER TIER OUTLETS SHOULD DRAIN INTO PAVED TERRACE DRAINS. ALTERNATIVE NO. 1 FILTER FABRIC MiN. 6" OVERLAP ALTERNATIVE NO. 2 TYPICAL 2 FT. X 2 FT. 3/4 IN. MAX. ROCK FILLED TRENCH WITH 4 IN. DIA. ABS OR PVC PIPE OR APPROVED SUBSTITUTE. PROVIDE MINIMUM 8 PERFORATIONS (1/4-IN. DIA.) PER LINEAL FOOT IN BOTTOM HALF OF PIPE. PIPE IS TO EXTEND FULL LENGTH OF BUTTRESS OR STABILIZATION FILL WITH A MINIMUM GRADIENT OF 2% TO OUTLET PIPES. 15' MIN. FINISHED GRADE 2' MIN. KEY DEPTH-15' MIN. KEY WIDTH OVEREXCAVATION - AS REQUIERD BY GEOTECHNICAL ENGINEER OR GEOLOGIST (3' MIN) BACKCUT BENCHED AT CONTACT \ 4" NON- PERFORATED PIPE TO BE PLACED AT LOTS LINES OR AS DESIGNATED BY THE GEOTECHNICAL ENGINEER OR GEOLOGIST 3' MIN. KEY DEPTH ALTA CALIFORNIA GEOTECHNICAL, INC VER. 3/12 PLATE G-8 PATHi\\l-S-WTGL96E\sliare\Alto Colifornio GeotechnlcolVDroftlng\GRADING BETAILSNG-S.dwg STABILIZATION FILL (UPSLOPE ALLUVIATED AREA) PROVIDE BERM, PAVED SWALE, AND/OR STORM DRAIN PER CIVIL ENGINEER CONSTRUCT STABILIZATION FILL (MINIMUM KEY 15'x2'x3') EXISTING TOPOGRAPHY APPROVED COMPETENT MATERIAL UPPER DRAIN AT ALLUVIUM/BEDROCK CONTACT. PROVIDE OUTLETS BASED UPON RECOMMENDATIONS OF GEOTECHNICAL ENGINEER OR GEOLOGIST BACK DRAIN PER DETAIL G-8 ALTA CALIFORNIA GEOTECHNICAL, INC VER. 3/12 PLATE G-9 PATH:\\LS-WrGL96e\shara\Aita California G«ot«chnleol\Drafflng\GRADING DETAILS\G-9.dwg SELECTIVE GRADING DETAIL FOR STABILIZATION FILL UNSTABLE MATERIAL EXPOSED IN PORTION OF CUT SLOPE EXISTING TOPOGRAPHY PROPOSED GRADE THE NEED FOR AND DEPTH OF OVEREXCAVATION TO BE DETERMINED BY THE GEOTECHNICAL -€NGtNEER/SEOLOGIST APPROVED COMPETENT MATERIAL IF RECOMMENDED BY THE GEOTECHNICAL ENGINEER/GEOLOGIST THE REMAINING CUT PORTION OF THE SLOPE MAY REQUIRE ' REMOVAL AND REPLACEMENT WITH A KEYWAY (V\^ ) AND COMPACTED FILL (SEE PLATE G-8) NOTES: 1. BACKDRAINS ARE NOT REQUIRED UNLESS SPECIFIED. 2. "W" SHALL BE EQUIPMENT WIDTH (15') FOR SLOPE HEIGHT LESS THAN 25 FEET. FOR SLOPES GREATER THAN 25 FEET, "W" SHALL BE DETERMINED BY THE PROJECT GEOTECHNICAL ENGINEER/GEOLOGIST. AT NO TIME SHALL "W" BE LESS THAN H/2. ALTA CALIFORNIA GEOTECHNICAL, INC . VER. 3/12 PLATE G-10 PATHi\\US-WTGL96E\share\Al-ta Californio GeotechnicolNDroftingNGRADING DETAILS\G-10.clwg SKIN FILL SLOPE OVER NATURAL GROUND EXISTING TOPOGRAPHY PROPOSED GRADE 15' MIN. 4' MIN. BENCH HEIGHT 15' MIN. TO BE MAINTAINED FROM SLOPE FACE TO BACKCUT MiN. KEY DIMENSIONS 15'X2'X3' NEED AND LOCATION OF HEEL DRAINS TO BE DETERMINED BASED UPON FIELD CONDITIONS IF REQUIRED, SEE DETAIL PLATE G-8 ALTA CALIFORNIA GEOTECHNICAL, INC. VER. 3/12 PLATE G-11 PATHi\\l-S-WTGL96E\sliore\Al-to Californio Geoteclinlcal\Brafting\GRADING DETAILS\G-ll.dwg DETAIL FOR MAXIMUM PARTICLE DIMENSION PROPOSED GR^E ZONES >10FT FILL SLOPE SURFACE ZONE DEPTH PARTICLE MAX. DIMENSION PLACEMENT METHOD 1 0-3 ft. ^1.0 ft. STANDARD OR CONVENTIONAL COMPACTION METHODS (SEE EARTHWORK SPECIFICATIONS) 2 3-7 ft. ^2.0 ft. ROCK BLANKETS (SEE PLATE G-13) 3 >10ft. <8.0 ft. ROCK BLANKETS (PLATE G-13) ROCK WINDROW (PLATE G-14) INDIVIDUAL ROCK BURIED (PLATE G-15) 4 15 HORIZONTAL FEET FROM FILL SLOPE FACE ^1.0 ft. STANDARD OR CONVENTIONAL COMPACTION METHODS (SEE EARTHWORK SPECIFICATIONS) ALTA CALiFORNiA GEOTECHNICAL, INC . VER. 3/12 PLATE G-12 PATHi\\LS-WTGL96ESshare\Alto Colifornio Geo-technlcal\Drafting\GRADING DETAILSSG-ia.dwg ROCK BLANKET DETAILS LOOSE PILE 1 I LOOSE, DUMPED ROCK, GRAVEL AND EiAND MIXTURE REMOVE FRAGMENTS LARGER THAT 2 FEET FOF| ISOLATED BURIAL (PUTE G-15) OR WINDROW (PLATE G-10) COMPACT PILE 1 SPREAD LOOSE PILE FORWARD WITH HEAVY TRACKED DOZER (D-8 OR LARGER). HEAVILY WATER, TRACK, AND APPLY ADDITIONAL SAND AND GRAVEL AS NECESSARY TO FILL VOIDS AND CREATE A DENSE MATRIX OF ROCK, COBBLES, GRAVEL AND SAND (2 FOOT MAXIMUM THICKNESS) APPROVED BOTTOM, OR TOP OF PREVIOUSLY APPROVED BLANKET FILL LOOSE PILE 2 DUMP SUCCESSIVE PILES OF LOOSE ROCK, GRAVEL ANO SAND MIXTURE ON FORWARD EDGE OF PREVIOUSLY COMPACTED UFT WITH TRUCKS AND/OR SCRAPERS, USE PREVIOUS LIFT TO ACCESS AND FURTHER COMPACT PILE 1 APPROVED BOTTOM, OR TOP OF PREVIOUSLY APPROVED BLANKET FILL LOOSE PILE 3 DUMP SUCCESSIVE PILES OF LOOSE ROCK, GRAVEL AND SAND MIXTURE ON FORWARD EDGE OF PREVIOUSLY COMPACTED LIFT WITH TRUCKS AND/OR SCRAPERS. USE PREVIOUS LIFT TO ACCESS AND FURTHER COMPACT EXISTING BLANKET. COMPACTED PILES 1 AND 2 APPROVED BOTTOM, OR TOP OF PREVIOUSLY APPROVED BLANKET FILL OBSERVATION TESflNG OBSERVE EQUIPMENT. SCRAPERS AND TRUCKS SHOULD EXCAVATE TEST/OBSERVATION PITS TO CONFIRM E>jlSTENCE VOIDS, AND FORMING A DENSE, COMPACTED FILL MATRIX RECORD LIMITS AND ELEVATION OF BLANKET, ALL F OBSERVATION OF THE GEOTECHNICAL ENGINEER. S CONFIRMATION OF SUITABIUTY OF FILL AND RELEASE ACCORDANCE WITH PLATE G-12. AND APPROVAL PROCEDURES BE FULLY SUPPORTED ON BLANKET WITHOUT SIGNIFICANT YIELDING. OF MIXTURE OF VARIOUS PARTICLE SIZES, WITHOUT SIGNIFICANT TEST BY ASTM D1556, D2922 AND/OR D3017 WHEN APPROPRIATE. LL AND COMPACTION OPERATIONS TO BE CONDUCTED UNDER THE JBSEQUENT LIFTS TO BE APPLIED ONLY AFTER OBSERVATION AND BY THE GEOTECHNICAL ENGINEER. BLANKETS TO BE CONSTRUCTED IN ALTA CALIFORNIA GEOTECHNICAL, INC VER. 3/12 PLATE G-13 PATH:\\LS-WTGL9eE\thor«\Alfa Callfomlo Oeot•chnl«o^D^lf»Ing\GRADING OETAiLS\G-l3-dwo PROPOSED ROCK WINDROW DETAIL GRADE PROPOSED SLOPE SURFACE <Z> h O WINDROW 4'_l (TYPICAL) NOTE: OVERSIZED MATERIAL SHOULD BE REMOVED FROM THE 15' CLEAR ZONES WITH SPECIAL EQUIPMENT, SUCH AS A ROCK RAKE, PRIOR TO PLACING THE NEXT FIU_ LIFT. VARIANCES TO THE ABOVE ROCK HOLD DOWN MAY BE GRANTED SUBJECT TO APPROVAL BY THE OWNER, GEOTECHNICAL ENGINEER, AND GOVERNING AGENCY TYPICAL WINDROW DETAIL (END VIEW) HORIZONTALLY PLACED COMPACTED FILL GRANULAR SOIL FLOODED TO FILL VOIDS NOTE: COMPACTED FILL SHALL BE BROUGHT UP TO A HIGHER ELEVATION ALONG EACH WINDROW SO GRANULAR SOIL CAN BE FLOODED IN A "TRENCH CONDITION". PROFILE VIEW ALTA CALIFORNIA GEOTECHNICAL, INC VER. 3/12 PLATE G-14 PATHi\\LS-WTGL96E\share\Al-to California Geo-technlcal\DraftlnQ\GRADING DETAILS\G-14.dwg ISOLATED ROCK BURIAL DETAILS bXISTING COMPACTED FILL EXCAVATE HOLE INTO EXISTING FILL PHISM, PLACE BOULDER (< 8 leel in maximum dimension) INTO EXISTING COMPACTED FILL. SURROUND V\/iTH SAND, GRAVEL, COBBLES AND WATER HEAVILY. TRACK WITH DB OR LARGER EQUIPMENT UNTIL RESULTING FILL FULLY SUPPORTS EQUIPMENT. OBSERVE AND/OR TEST IN ACCORDANCE Wl II I ASTM Dl 55B. D29?2 OR D3017 ROCKS LARGER THAN 8 FEET SHALL BE FURTHER REI^UCED IN SIZE BY SECONDARY BREAKING EXISTING COMPACTED FILL ALTA CALIFORNIA GEOTECHNICAL, INC VER. 3/12 PLATE G-15 PATH:\\LS-WTGL96E\shar«\Aita California G«et«chnieal\DrafHng\QRADiNG DETAILS\G-15,dwg RELATIVE COMPACTION VS. DEPTH CANYON WALL LAY BACK DIFFERENTIAL FILL OVEREXCAVATION DETAILS EXISTING TOPOGRAPHY PROPOSED GRADE ALTA CALIFORNIA GEOTECHNICAL, INC VER. 3/12 .APPROVED COMPETENT MATERIAL 1. ALL FILL PLACED BELOW 50 FEET OF FINISHED GRADE SHALL BE COMPACTED TO A MINIMUM OF 93% RELATIVE COMPACTION. 2. CANYON WALLS WITHIN 50 FEET OF FINISHED GRADE SHALL BE LAID BACK TO A SLOPE RATIO OF 2:1 OR FLATTER. 3. ALL BUILDING PADS SHALL BE OVER EXCAVATED TO A MINIMUM OF 1/3 OF THE MAXIMUM DEPTH OF FILL BELOW THE BUILDING PAD TO A MAXIMUM OF 17 FEET. 4. IF THE 2:1 LAY BACK OF THE CANYON WALL IS IMPRACTICAL, THEN AS AN ALTERNATIVE THE INCREASED COMPACTION STANDARDS IN NOTE 1 SHOULD BE EXTENDED UP TO H/3 AND THE LAY BACK WILL NOT BE REQUIRED. _ PLATE G-16 PATHi\\LS-WTCL96E\sharc\Al-tQ Colifornio Geotechnlcal\Drafting\GRADING DETAILS\G-16.dwg SETTLEMENT PLATE DETAIL 2'X2' X 1/4" STEEL PLATE STANDARD 3/4" PIPE NIPPLE, WELDED TOP AND UNDERSIDE OF PLATE. 3/4" DIA. X 5' LONG GALVANIZED PIPE, STANDARD PIPE THREADS TOP AND BOTTOM. EXTENSIONS THREADED BOTH ENDS AND ADDED IN 5' INCREMENTS. 3" DIA. SCHEDULE 40 PVC, ADD IN 5' INCREMENTS, GLUE JOINTS. CAP AND COVER PER PLATE G-12A \ FINAL GRAlbE / 2.5' f — 5' 5' 1/ 5' 5' 5' 1/ •'^^^l.-'ci'i'.S^'Ti-A 1 MAINTAIN 5' HORIZONTAL CLEARANCE FOR HEAVY EQUIPMENT. HAND COMPACT IN 2' VERTICAL INCREMENTS OR ALTERNATIVE SUITABLE TO AND ACCEPTED BY THE GEOTECHNICAL ENGINEER. HAND COMPACT INITIAL 5' (VERTICAL) WITHIN 10' HORIZONTAL PLACE AND HAND COMPACT INITIAL 2' OF FILL PRIOR TO ESTABLISHING INITIAL READING ^ REMOVAL BOTTOM PROVIDE 1-INCH OF SAND/GRAVEL BEDDING MINIMUM NOTES: 1) LOCATIONS OF SETTLEMENT PLATES SHALL BE CLEARLY MARKED AND READILY VISIBLE (RED FLAGGED) TO EQUIPMENT OPERATORS. 2) 3) CONTRACTOR SHALL MAINTAIN 10' HORIZONTAL CLEARANCE FOR HEAVY EQUIPMENT WITHIN 5' (VERTICAL) OF PLATE BASE. FILL WITHIN CLEARANCE AREA SHALL BE HAND COMPACTED TO PROJECT SPECIFICATIONS OR COMPACTED BY ALTERNATIVE APPROVED BY THE QEOTECHNICAL ENGINEER. AFTER 5' (VERTICAL) OF FILL IS IN EQUIPMENT CLEARANCE. FILL IN APPROVED ALTERNATIVE) IN VERTICA PLACE, CONTRACTOR SHALL MAINTAIN 5' HORIZONTAL CLEARANCE AREA SHALL BE HAND COMPACTED (OR L INCREMENTS NOT TO EXCEED 2 FEET. 4) IN THE EVENT OF DAMAGE TO SETTLEMENT PLATE OR EXTENSION RESULTING FROM EQUIPMENT OPERATING WITHIN PRESCRIBED CLEARANCE AREA, CONTRACTOR SHALL IMMEDIATELY NOTIFY GEOTECHNICAL. ENGINEER AND SHALL BE RESPONSIBLE FOR RESTORING THE SETTLEMENT PLATE AND EXTENSION RODS TO WORKING ORDER. ALTA CALIFORNIA GEOTECHNICAL, INC . i VER. 3/12 1 PLATE G-1 7 PATHiV^^LS-WTGLSeENshoreVAlto California Geo-technlcal\Dr<jiftlng\GRADING DETAILS\G-17,dwg SURFACE SETTLEMENT MONUMENT DETAIL FINISH SURFACE CONCRETE OR PLASTIC SPRINKLER VAULT PVC CAP I i II i l|- 3'8" LONG #8 RFBAR OH 3/4" GALVANIZED PIPE 4" SCH. 40 PVC PIPE V. -6' -2' CONCRETE OR SLURRY 3 FLEI MIN. APPROX. 6" EMBEDMENT INTO COMPACTED FILL ALTA CALIFORNIA GEOTECHNICAL, INC VER. 3/12 PLATE G-18 PATHi\M-S-WTGL96E\share\Alto California GeoteclinlcolVDroftlngNGRADING DETAILS\G-18.dwg R/w VARIES LOT LENGTH (VARIES) PAD ELEVATION AS SHOWN ON PLAN .VARIABLE UNDERCUT SLOPE & DEPTH DEPENDING ON UTILITY DEPTH TYPICAL STREET, PARKWAY AND PAD UNDERCUT 1.0' MIN BELOW 'LOWEST UTILITY NO SCALE ALTA CALiFORNiA GEOTECHNICAL, INC VER. 3/13 PLATE G-19 PATHi \\LS-WTGL96E\sliore\Al-ta California GeotechnlcalXDraftIngXGRADING DETAILS\G-19.dwg ALTA CALIFORNIA GEOTECHNICAL INC. 16870 West Bernardo Drive Suite 445 San Diego, CA 92127 www.altageotechnical.com CITY VENTURES 1900 Quail Street Newport Beach, California 92660 March 12, 2014 Project Number 2-0068 Attention: Mr. Andy Gerber, Director of Development Subject: GEOTECHNICAL UPDATE LETTER Review of Proposed Precise Grading and Improvement Plans, Valley 17 Project, Tentative Tract CT 12-07, located at Valley Street and Oak Avenue City of Carlsbad, California References: Attached Mr. Andy Gerber: Presented herein is Alta California Geotechnical, Inc.'s (Alta's) geotechnical update letter for the Valley 17 project. Tentative Tract Ct 12-07, located at Valley Street and Oak Avenue in the City of Carlsbad, California. This update represents Alta's review ofthe referenced proposed Precise Grading and improvement Plans. Additionally, this update represents Alta's response to the City of Carlsbad Land Development Engineering first plan check comments dated De- cember 13, 2013. A copy of those comments is attached herein. Alta has reviewed the referenced, proposed Precise Grading Plans (Huitt-Zollars, 2014a) and referenced, proposed Improvement Plans (Huitt-Zollars, 2014) with respect to the geotechnical recommendations presented in the referenced geotechnical report (Alta, 2013). In conclusion, the Precise Grading Plan and Improvement Plans are found to be in general conformance with the geotechnical recommendations for the Valley 17, Tentative Tract CT 12-07 project. The geotechnical recommendations presented in Alta, 2013 remain applicable to the current de- sign. Riverside Office Phone: 951.509.7090 San Diego Office Phone: 858.674,6636 Project Number 2-0068 March 12, 2014 Page 2 Earthwork estimates prepared bythe civil engineer (Huitt-Zollars, 2014a) are: 148 cubic yards of cut, 14,312 cubic yards of fill and 14,164 cubic yards of import. Alta has transfer the existing geotechnical information onto the proposed Precise Grading Plans (Sheets 4 through 9 of 9) and they are attached herein. The opportunity to be of service is greatly appreciated. If you have any questions or should you require any additional information, please contact the undersigned at (619) 920-2694. Al- ta appreciates the opportunity to provide geotechnical consulting services for your project. Sincerely, Alta California Geotechnical, Inc. SCOTT A. GRAY/RGE 2857 Reg. Exp.: 12-31-14 Registered Geotechnical Engineer Vice President DA^A. MURPHYA Reg. Exp.: 10-30-15 Certified Engineering Geologist President Distribution: Addressee Huitt-Zollars; Attn: Peter Bernard Attachnfients: Carlsbad review comnnents SAG/DAM: dam-2-0058, March 11, 2014 (Geotechnicai Update, Valley 17, Valley & Oak, Carlsbad) ALTA CALIFORNIA GEOTECHNICAL, INC. Project Number 2-0068 Page 3 March 12, 2014 References Alta California Geotechnical, Inc., 2013, Preliminary Geotechnical Investigation, Tentative Tract CT 12-07, Valley Street and Oak Avenue, City of Carlsbad dated October 24, 2013 (Project Number 2-0068). Huitt-Zollars, 2014, Improvement Plans for Valley 17, Sheets 1 through 8 of 8, City of Carlsbad, California, Project No. CT 12-07, dated March 11, 2014. Huitt-Zollars, 2014a, Precise Grading Plans for Valley 17, Sheets 1 through 9 of 9, City of Carls- bad, California, Project No. CT 12-07, dated March 10, 2014. ALTA CAUFORNIA GEOTECHNICAL, INC. ALTA CALIFORNIA GEOTECHNICAL INC. CITY VENTURES 1900 Quail Street Newport Beach, California 92660 170 North IWaple Sfreet, Suite 108 Corona, CA 92880 www.altageoteehnical.com October 24, 2013 Project Number 2-0068 Attention: Mr. Andy Gerber Director of Development Subject: PREUMINARY GEOTECHNldf^L INVESTIGATION Tentative Tract CT 12-07, Va City of Carlsbad, California References; See Appendix A ley Street and Oak AvenuJ^^^^^^^^ NOV 27 2013 LANU ucVELOPMENT ENGINEERING Mr. Andy Gerber: Presented herein Is Alta California Geotechjilcal, Inc.'s (Alta) preliminary geotechnical investigation of Tentative Tract CT 12-07, located at Valley Street and Oak Avenue, in the City of Carlsbad, County of San Diego, California. The conclusions and recommendations presented In this report are based on Alta's subsurface Ir vestigatlon, the enclosed Tentative Map (Sheet 2 of 3) provided by Huitt-Zollars, laboratory testing and review/ ofthe referenced reports. Alta's review ofthe data and site plan indicates that the proposed development is feasible, from a geotechnical standpoint, provided that the recommendations presented in this report are incorporated Into tjie grading and Imprcjvement plans, and implemented during site development. Included In this report are: ^IIZir^aA .^M UA)^^!^ \e.irs^ f . . t~. -1 w ...... • Recommendations for remedial and • Geotechnical recommendations for ;;ite construction; • Discussion ofthe site geotechnical conditions; J " , -c, in, site grading, Including unsuitable soil removals; n?..^!.^ V- cjv^ft^-^ iVJ>^i 3 1 Preliminary foundation design para4eters. San Dlego Office Phone: 858 674.6636 Corona Office Phone: 951.509.7090 Project No. 2-0068 Pagg g October 24, 2013 2.0 PROJEa DESCRIPTION 2.1 Site Location and Existing Conditions The rectangular-shaped site cjonsists of approximately 3.76-acres located at the south corner of the intersect! an of Valley Street and Oak Avenue, in the City of Carisbad, County of San Dlegcji, California (Figure 1). Topographically, the site is relatively flat and gently slopes to the west. Elevations range from approximately 169 to 154 feet, The site is currently vacant, lj Is our understanding that the site has historically been used for agricultural puifposes, Native grasses and weeds cover the majority of the site, Some trees are ptjesent at the eastern corner of the site, as well as at the southwest corner ofthe sjte, near the terminus ofthe existing James Drive. 2.2 Proposed Development The proposed development cjmsists ofthe extension of James Drive from Valley Street to the south corner ofthe site as shown on enclosed Sheet 2 of 3, and the development of seventeen (17) lots for single family residences. Infrastructure improvements are proposed, jnciuding the construction water, sewer and storm drain in proposed James Drlv4. Some underground and surface improvements are also proposed for the exisjting Oak Avenue and Valley Street. Lot elevations are proposed from a high of 1^9.0 feet in the northeast portion ofthe site to a low of 159.4 feet on the soutii edge ofthe property. Earthwork estimates prepared by the project civil ejigineer are{ 1,878 cubic yards of cut, 10,982 cubic /fardsof fill and 9,104 cubic yajrds of import. , , f It is Alta s understanding that 'portions of the soil onsite may require remediation ,J/, for environmental concerns. The scope of the remediation is not known at this v-i,, ^ ALTA CAUFORhliA GEOTECHNICAL, INC. Project No. 2-0068 October 24, 2013 8.0 FUTURE PLAN REVIEWS This report represents a geotechnical review ofthe Tentative Tract IVIap. As the i -~ ' ' project design progresses, site specific geologic and geotechnical issues shouid be considered in the design and construction ofthe project. Consequently, future plan reviews may be necessary, These reviews may include reviews of: > Grading Plans > Environmental Remediationj Plans for Soils > Foundation Plans > Utility Plans These plans should be forwarded ^o the project Geotechnical Consultant for review. 9.0 CLOSURE 9.1 Geotechnical Revievtf Forthe purposes ofthis report, multiple working hypotheses were established for the project, utilizing the availiable data and the most probable model is used for the analysis, Future Information collected during the proposed grading operations is intended to evaluate the hypothesis and as such, some ofthe assumptions summarized in this report may need to be changed. Some modifications ofthe grading lecommendations may become necessary, should the conditions encountered in the field differ from the conditions hypothesized In this report. Plans and sections ofthe proj]ect specifications should be reviewed by Alta, to evaluate conformance with tijie intent ofthe recommendations contained in this i report. If the project descriptjion or final design varies from that described In herein, Alta must be consuitejd regarding the applicability ofthe recommendations contained |ierein and whether any changes are required. Aita I ALTA CALIFORRIIA GEOTECHNICAL, INC. TENTATIVE TRACT MAP NO. CT 12-07/ SDP12-07 VALLEY STREET AND OAK AVENUE CARLSBAD. CALIFORNIA ALTA CALIFORNIA GEOTECHNICAL INC. 170 North IMaple Street, Suite 108 Corona, CA 92880 www.aitageotechnicai.com CITY VENTURES 1900 Quail Street Newport Beach, California 92660 July 22, 2014 Project Number 2-0068 Attention: Mr. Andy Gerber, Director of Development Subject: UPDATED PRECISE GRADING AND IMPROVEMENT PLAN REVIEW Valley 17 Project, Project Number CT 12-07 Located at Valley Street and Oak Avenue Cityof Carlsbad, California References: Appendix Mr. Gerber: Presented herein is Alta California Geotechnical, Inc.'s (Alta's) updated precise grading and improvement plan review for the Valley 17 project, Project Number CT 12-07, located at Valley Street and Oak Avenue In the City of Carlsbad, California. This updated letter is based on our review of the most recent precise grading and improvement plans for the project and the recommendations presented in our geotechnical investigation report (Alta, 2013a). Alta has reviewed the referenced Precise Grading Plans (Huitt-Zollars, 2014a) and referenced Improvement Plans (Huitt-Zollars, 2014) with respect to the geotechnical recommendations presented in the referenced geotechnical report (Alta, 2013). The Precise Grading Plans and Improvement Plans were found to be in general conformance with the geotechnical recommendations for the project. San Diego Office Phone; 858.674.6636 Corona Office Phone: 951.509.7090 Project Number 2-0068 July 22, 2014 Page 2 The opportunity to be of service is greatly appreciated. If you have any questions or should you require any additional information, please contact the undersigned at (858) 674-6636. Alta appreciates the opportunity to provide geotechnical consulting services for your project. Sincerely, Alta California Geotechnical, Inc. Registered Geotechnical Engineer Vice President Distribution: (3) Addressee SAG; dam-2-0068, July 22,2014 (Updated Grading Plan Review, Valley St. & 0al< Ave.) ALTA CALIFORNIA GEOTECHNiCAL, INC. Project Number 2-0068 Page 3 July 22, 2014 APPENDIX References Alta California Geotechnical, Inc., 2013a, Preliminary Geotechnical Investigation, Tentative Tract CT 12-07, Valley Street and Oak Avenue, City of Carlsbad dated October 24, 2013 (Project Number 2-0068). Alta California Geotechnical, Inc., 2013b, Foundation Plan Review, Tentative Tract CT 12-07, Valley Street and Oak Avenue, City of Carlsbad dated December 2, 2013 (Project Number 2-0068). Alta California Geotechnical, Inc., 2014, Geotechnical Update Letter, Review of Proposed Pre- cise Grading and Improvement Plans, Valley 17 Project, Tentative Tract CT 12-07, Valley Street and Oak Avenue, City ofCarlsbad, dated March 12, 2014 (Project Number 2-0068). Huitt-Zollars, 2014, Improvement Plans for Valley 17, Sheets 1 through 8 of 8, City of Carlsbad, California, Project No. CT 12-07, dated March 11, 2014. Huitt-Zollars, 2014a, Precise Grading Plans for Valley 17, Sheets 1 through 13, City of Carlsbad, California, Project No. CT 12-07, dated July 18, 2014. ALTA CALIFORNIA GEOTECHNICAL, INC. ^ISLM 2.21 gfS" ' I.OI • •'i f H -4-•# p| ^ 16167 TW ICJ 1614 r «isr LEGEND Qop OLD PARALIC DEPOSIT B-1 O LOCATION OF HOLLOW STEM BORING B-4# LOCATION OF HAND-AUGER BORING ANTICIPATED DEPTH OF REMOVAL (FEET) / SCALE: 1"=10' SEE SHEET 6 ALTA CALIFORNIA GEOTECHNiCAL, INC . 16870 WEST BERNARDO DRIVE. SUITE 445, SAN DIEGO, CA 92127 TELEPHONE: (858) 674-6636 PROJECT NUMBER: 2-0068 DATE: 3-t2-U Vim qniunr sian nsuac KSCSffnOR vouju nquntxs (cr) vouna PBoviDiu icr) AMU UayuBD m BIT 1 BIT B EUT C ASEA aURETENIKM 4 210 sto 157 »7.50 l5e.7S 155.75 250 sr 208 2W Its 159.4 )5a«s 157.85 250 SF 202 210 155 l«2.8 1(2.15 ISI. 15 250 sr PREPARED BY: HUm-ZDUARS HuiU-ZollarB, Irw. Thousand Oaks 90 E. Thoutand Oak« Boulevard Suite 201 Thousand Oaks, California 91360 PhOKB (BOS) 416-1602 Fax (BOS) 418-1619 PETER M- BERNARD. P.E. ENGINEER OF WORK REVISION DESCRIPTION OTHER APPROVAL CITV APPROVAL SHEET 4 REVIEWED BY: CITY OF CARLSBAD ENGINEERING DEPARTMENT SHEETS 9 PRECISE GRADING PLANS FOR: VALLEY 17 PRECISE GRADING SDP 12-07 GLEN K, VAN PESKI ENGINEERING MANAGER PE t1204 EXPIRES 3/31/15 DATE Dim BY: _ CHKD BY: . RVWD BY: PROJECT NO CT 12-07 ORAWNG NO. 480-4A nim Quiunr man nsnat raum nqtniD (») TOLDHI PKOVIDD m KK TvtnSii (ar) BIT B BUT C IKEl SKKTTENTXM 1 202 210 >M I5&J6 155.61 154.61 250 SF aOKTCNTION 2 207 210 154 158109 155. J4 f54.J4 250 sr BOROENTXIN J 208 210 185 >5S.4 155.85 154.65 250 SF 1 UTB qVlUTY BUW DBaHM DBSCBIPIION Touna BSWUBBD (cr) mLDHB psonun) (cr) m TnawR (ar) HI? 1 BUT B BUT C iBU BKlRnmHON 7 207 210 160 167.50 188.55 185.55 250 SF BKKmimN 8 202 210 155 184.8 184.05 16j:05 250 SF aoRnomoN a 208 210 166 1827 181.95 160.95 250 SF l\G4S0-4A-5n9et4 d;,g. Lz:0'^:: Sheets. isurni I57J0 ff (1818) SEE SHEET 5 —i SEE PROJECT GEOTECH REPORT AND STRUCTURAL PUNS FOR SLAB THICKNESS AND UNDERLAYMENT UID qtumr BION uanar DDcnraoN TDUDIB EmaiBD (») Tounn noma (W) RU nBdnmn (ar) EUTA BUT B BUT C iBU BIOKTtNTION 10 202 210 155 181.00 18025 15^25 250 SF BtOKmVON 11 209 210 174 159.40 158.65 15785 250 SF SKMCTENDON 12 209 210 155 157.75 157.00 156.00 250 SF SEE SHEET 6 l\ 16117 Itl.ltfL 163.I11C > i6i(ia /! IIK6.7J IS l\ ^ "1 r J L J t66J FS KSr s i IK . I\ /I 1! i\ 1 16106M^ IM.761E iiuen. -Sg —!— „ 1- im \ w IKBTTC KSJTFl 1(M4.S3 anrr (-IB' !S!!!E " 167J5H: TBTJQSC o re PL ii PREPARED BY: Hurrr-zuABS Huitt-Zollars, Inc. Thotuand Oaks 90 E. Thousand Oaks Boulevard Suite 201 Thousand Oaks, California 91360 Phone {B05) 416-1802 Fax IB05) 416-1619 SHEET 8 CITY OF CARLSBAD ENGINEERING DEPARTMENT SHEETS 9 SHEET 8 CITY OF CARLSBAD ENGINEERING DEPARTMENT SHEETS 9 SHEET 8 CITY OF CARLSBAD ENGINEERING DEPARTMENT SHEETS 9 PRECISE GRADING PLANS FOR: VALLEY 17 PRECISE GRADING SDP 12-07 PRECISE GRADING PLANS FOR: VALLEY 17 PRECISE GRADING SDP 12-07 PRECISE GRADING PLANS FOR: VALLEY 17 PRECISE GRADING SDP 12-07 PRECISE GRADING PLANS FOR: VALLEY 17 PRECISE GRADING SDP 12-07 PRECISE GRADING PLANS FOR: VALLEY 17 PRECISE GRADING SDP 12-07 APPROVED: GLEN K VAN PESKI APPROVED: GLEN K VAN PESKI ENGINEERING MANAGER PE 41204 EXPIRES 3/31/15 DATE A DVIN BY CHKD Bl RVMD B PROJECT NO. CT 12-07 DRAWING NO. 480-4A DATE INITIAL REVISION DESCRIPTION DATE INITIAL DATE INITIAL DVIN BY CHKD Bl RVMD B PROJECT NO. CT 12-07 DRAWING NO. 480-4A ENQNEER QF WORK REVISION DESCRIPTION OTHER APPROVAL OTY APPROVAL DVIN BY CHKD Bl RVMD B f: PROJECT NO. CT 12-07 DRAWING NO. 480-4A -GP'ij'NG G-4aQ-4--5h = = l4 j..g.