Loading...
HomeMy WebLinkAboutHMP 15-01; MARTIN RESIDENCE; GEOTECHNICAL PLAN REVIEW UPDATE; 2013-11-07NNEERII;J C. I I RECORD COPY 2450 Auto Park Way Escondido, California 92029-1229 Job #13-234-P QryL.... -2,1 -71t1 I Phone (760) 743-1214 Initial ate Fax (760) 739-0343 D November 7, 2013 -- Mr. Neil A. Martin OCT 09 2014 1878 Shadetree Drive LAN San Marcos, California 92078 Ii VLU1VI1NT ENGINEEP,1JG GEOTECHNICAL PLAN REVIEW UPDATE, PROPOSED SINGLE .FAMILY RESIDENTIAL DEVELOPMENT, ADAMS STREET, CARLSBAD (A.P.N. 206-200-03) Pursuant to your request, Vinje & Middleton Engineering, Inc. has completed the attached Geotechnical Plan Review Update report for a proposed single-family residential development at the above-referenced project property. The following report summarizes the results of our review of previous report and pertinent documents, current shallow sampling and testing, and provides update and amended conclusions and recommendations for the proposed development based on the project plans, current codes and engineering standards. From a geotechnical engineering standpoint, it is our opinion that the project site remains suitable for the proposed single family residential development and associated improvements provided the recommendations presented in this report are incorporated into the design and construction of the project. The conclusions and recommendations provided in this study are consistent with the site indicated geotechnical conditions and are intended to aid in preparation of final development plans and allow more accurate estimates of development costs. If you have any questions or need clarification, please do not hesitate to contact this office. Reference to our Job #13-234-P will help to expedite our response to your inquiries. We appreciate this opportunity to be of service to you. I I I VINJE & MIDDLETON ENGINE 4Me o a~t ' 4hi Shan G#2885 I I INC. I I 1 I I I I I 1 1 I -I I I 1 I I I I Geotechnical Plan Review Update Proposed Single-Family Residential Development Adams Street, Carlsbad (A.RN. 206-200-03) November 7, 2013 Prepared For: Mr. Neil A. Martin 1878 Shadetree Drive San Marcos, California 92078 Prepared By: VINJE & MIDDLETON ENGINEERING, INC. 2450 Auto Park Way Escondido, California 92029 Job #13-234-P I GEOTECHNICALPLAN REVIEW UPDATE PROPOSED SINGLE-FAMILY RESIDENTIAL DEVELOPMENT ADAMS STREET, CARLSBAD I (A.P.N. 206-200-03) I. INTRODUCTION Project most current Preliminary Grading Plan for the proposed single-family residential I construction at the above-referenced property, prepared by Sowards & Brown Engineering (dated October 15, 2013), was provided to us for review and comments. A copy of the I Preliminary Grading Plan is reproduced herein and included with this transmittal as a Geotechnical Map, Plate 1. The project property is a vacant lot located on a modest south facing hillside on the north margin of the Agua Hedionda Lagoon, within the limits of City of Carlsbad. Approximate site location is shown on a Vicinity Map included on Plate 1. I The approximate site coordinates are 33.1450°N latitude and -117.3268°W longitude. I Surface and subsurface geotechnical conditions at the project property, and adjacent properties, were previously studied by this office for the purpose of a planned residential development, as proposed at that time. Our findings, conclusions, and recommendations I were presented in the following written technical report: "Preliminary Soil and Geotechnical Investigation Parcels A, B, C APN # 260-200-03, 04, & 05 Adams Street Carlsbad, California" I Job #98-257-P, report dated August 10, 1998. The referenced report was reviewed in connection with this effort and a copy is attached to this transmittal as and an Attachment. The project property is designated as Parcel A in the referenced report. The purpose of this work was to review the project Preliminary Grading Plan to assure its compatibility with the site indicated geotechnical conditions as presented in the referenced report, and to provide update and/or amended recommendations consistent with the current codes and engineering standards. The updated and/or amended recommendations provided in the following sections will supplement or supersede those given in the attached report where specifically applicable. Our effort in connection with the preparation of this update report also included a site visit by our engineering geologist on August 22, 2013 to observe current surface conditions. A shallow test pit was also excavated during our recent site visit for collection of a representative soil sample used to perform additional pertinent laboratory testing. I I [1 \TINJE & MIDDLETON ENGINEERING, INC. 1 2450 Auto Park Way 0 Escondido, California 92029-1229 0 Phone (760) 743-1214 I II' I Geotechnical Plan Review Update, Proposed Single-Family Residential Page 2 Development, Adams Street, Carlsbad (A.P.N. 206-200-03) November 7, 2013 II. SITE DESCRIPTION Based on our recent site visit, the project property remains substantially unchanged from conditions described in the attached report. The project property chief ly consists a modest south facing natural hillside that descends from Adams Street to the Agua Hedionda Lagoon at gradients generally approaching 4:1 maximum. Surface areas are locally mantled by grass and weeds. Site drainagejsi'beetflows over the terrain to the lagoon. Excessive scouring or erosion is not in evidence at the property Ill. PROPOSED DEVELOPMENT The project Preliminary Grading Plan (Plate 1) depicts the construction of a multi-level single-family residential structure in the central portion of the property. Access to the residence will be provided from Adam Street via a S-shaped driveway that descends at gradients approaching 20% maximum to a level motor court and detached garage. Retaining walls and backfills against the garage northern basement type wall approaching 12 feet high are incorporated into the design for achieving the upper driveway profiles and lower motor court/garage pad grades near 51 feet elevation above mean sea level (MSL). The residence will consist of split level construction with a lower basement type floor proposed at near 33 feet and 36 feet elevation (MSL). Vertical cut excavations on the order of 12 and transition retaining wall on the order of 15 feet high are proposed for establishing residence's lower basement grades and upper floor levels at 51 feet elevation (MSL) near the motor court/garage grades. Associated improvements will consist of a swimming pool and spa with surrounding concrete decking along the lower southern margins near 37 feet elevation (MSL), concrete stairs and transition retaining walls. Also included are bio retention basins with gravels and perforated pipes along the eastern and western property margins which will connect to storm drain facilities, underground BMP vaults, and BMP cistern. Exposed graded cut or fill embankments are not planned. All ground transitions will be achieved by retaining and building basement type walls. Project earthwork associated with development of level building surfaces will chiefly consist of cut excavations and wall backfilling operations Actual earthwork quantities are dFrhtlyun known,however, it is anticipated that the project will cfiifl9be a Llanced grading operation. $ I I I VINJE & MIDDLETON ENGINEERING, INC. 1 2450 Auto Park Way ° Escondido, California 92029-1229 Phone (760) 743-1214 I I I 1 Geotechnical Plan Review Update, Proposed Single-Family Residential Page 3 Development, Adams Street, Carlsbad (A.P.N. 206-200-03) November 7, 2013 Foundation plans and details are not yet available. However, the use of masonry block basement type retaining walls at pad and floor level transitions, and wood-frame structure with exterior stucco supported on shallow stiff continuous strip and spread pad concrete footings with lower slab-on-grade floor foundations is anticipated. IV. GEOTECHNICAL CONDITIONS Geotechnical conditions at the project property remain the same as reported in detail in the I referenced report (see Attachment). In general, the property is underlain by Pleistocene age sandstone Terrace Deposits (Qt) atop Eocene age formational sandstone rocks. Site surfaces are mantled by shallow silty to clayey sand topsoil / colluvial deposits. Shallow I fills are also present along the upper north edge of the property associated with Adams Street road embankments. Surface or subsurface water was not observed nor encountered at the project property. W Existing modest sloping hillside terrain at the project property is performing well with no indication of landslides or other forms of slope or geologic instability. Natural Terrace Deposits and formational rock underlying the property are characteristic of local coastal areas, and typically perform well in natural and graded slope conditions. Project Terrace Deposits I formational rocks will provide good support for planned structures and I improvements. More detailed descriptions of site earth materials are presented on the test pits logs included as Plates 2 through 5 in the Attachment. Approximate Test Trench locations are transferred from our previous work and are shown -on the enclosed Plate 1. Logs of the I Test. Trenches are included in the enclosed Attachment (Plates 2 through 5 of the Attachment). A Geologic Cross-Section based on existing site conditions, proposed construction, and indicated subsurface profiles are included as Plate 2. I V. SEISMIC GROUND MOTION VALUES I For design purposes, site-specific seismic ground motion values were determined in accordance with the California Building Code (CBC). The following parameters are consistent with the indicated project seismic environment and our experience with similar earth deposits in the vicinity of the project site, and may be utilized for project design work: TABLE I Site Class ts Si Fa Fv SMs S NJ i SDS SD1 D 1.281 0.483 J 1.0 1.517 1.281 0.732 0.854 J 0.488 According to Chapter 16, Section 1613 of the 2010 California Building Code. VINJE & MJDDLETON ENGINEERING, INC. 1 2450 Auto Park Way' Escondido, California 92029-1229 Phone (760) 743-1214 1 Geotechnical Plan Review Update, Proposed Single-Family Residential Page 4 Development, Adams Street, Carlsbad (AP.N. 206-200-03) November 7, 2013 I Explanation: S5: Mapped MCE, 5% damped, spectral response acceleration parameter at short periods. Si: Mapped MCE, 5% damped, spectral response acceleration parameter at a period of 1-second. Fa Site coefficient for mapped spectral response acceleration at short periods. Fv:. Site coefficient for mapped spectral response acceleration at 1-second period. I . SMS: The MCE, 5% damped, spectral response acceleration at short periods adjusted for site class effects (SMSFaSs). SM1: The MCE, 5% damped, spectral response acceleration at a period of 1-second adjusted for site I class effects (SM1FvS1). Design, 5% damped, spectral response acceleration parameter at short periods (SDs=2 SDS: /3SMs). SDi: Design, 5% damped, spectral response acceleration parameter at a period of 1-second I Site peak ground accelerations (PGA) based on 2 percent probability of exceedance in 50 years defined as Maximum Considered Earthquake (MCE) with a statistical return period of 2,475 years is also evaluated herein in accordance with the requirements of CBC Section 1613 and ASCE Standard 7-05. Based on our analysis, the site PGAMcE was estimated to be 0.54g using the web-based United States Geological Survey (USGS) ground motion calculator. The design PGA determined as two-thirds of the Maximum Considered Earthquake (MCE) was estimated to be 0.36g. VI. ADDITIONAL SAMPLING, LABORATORY TESTING AND TEST RESULTS A shallow test pit was excavated at a selected location as part of this effort to collect a representative sample of onsite near surface soils for subsequent added laboratory testing for a corrosion assessment in the support of this update study. The following added tests were completed on the recently collected sample and will supplement those previously performed and presented in the enclosed Attachment: 1. pH and Resistivity Test: pH and resistivity of representative near surface soils was determined using "Method for Estimating the Service Life of Steel Culverts," in accordance with the California Test Method (CTM) 643. The test result is tabulated in Table 4. TABLE 2 r Sample Location Soil Type J Minimum Resistivity (OHM-CM) pH 1 I -Surface Soil I Red brown silty sand T 1848 6.9 VINJE & MIDDLETON ENGINEERING, INC. 0 2450 Auto Park Way 0 Escondido, California 92029-1229 0 Phone (760) 743-1214 Geotechnical Plan Review Update, Proposed Single-Family Residential Page 5 Development, Adams Street, Carlsbad (A.P.N. 206-200-03) November 7, 2013 2. Sulfate Test: A sulfate test was performed on representative near surface soils in accordance with the California Test Method (CTM) 417. The test result is presented in Table 2. TABLE 2 Sample Location Soil Description Amount of Water Soluble Sulfate In Soil (% by Weight) Surface Soil I Red brown silty sand Less than 0.001 rn 3. Chloride Test: A chloride test was performed on a representative sample of near surface soils in accordance with the California Test Method (CTM) 422. The test result is presented in Table 3. I L Sample Location Soil Description Amount of Water Solub Chloride L In Soil (% by Weight) I Surface Soil I Red brown silty sand I 0.006 VII. SITE CORROSION ASSESSMENT A site is considered to be corrosive to foundation elements, walls and drainage structures if one or more of the following conditions exist: * Sulfate concentration is greater than or equal to 2000 ppm (0.2% by weight). * Chloride concentration is greater than or equal to 500 ppm (0.05 % by weight). * pH is less than 5.5. For structural elements, the minimum resistivity of soil (or water) indicates the relative quantity of soluble salts present in the soil (or water). In general, a minimum resistivity value for soil (or water) less than 1000 ohm-cm indicates the presence of high quantities of soluble salts and a higher propensity for corrosion. Appropriate corrosion mitigation measures for corrosive conditions should be selected depending on the service environment, amountof aggressive ion salts (chloride or sulfate), pH levels and the desired service life of the structure. Results of limited laboratory tests performed on selected representatives of site samples indicate that the minimum resistivity is greater than 1000 ohm-cm suggesting presence of low quantities of soluble salts. Test results further indicated that pH levels are greaterthan 5.5, sulfate concentrations are less than 2000 ppm, and chloride concentration levels are less than 500 ppm. Based on the results of the corrosion analyses, the project site is VINJE & MIDDLETON ENGINEERING, INC. 2450 Auto Park Way Escondido, California 92029-I229 Phone (760) 743-1214 Geotechnical Plan Review Update, Proposed Single-Family Residential Page 6 Development, Adams Street, Carlsbad (A.P.N. 206-200-03) November 7, 2013 considered non-corrosive. However, the project site is located within 1000 feet of salt or brackish water (Aqua Hedionda Lagoon). Consequently, corrosion mitigation is appropriate, and should be implemented and incorporated into the design of planned structures and associated improvements as appropriate and necessary. A corrosion engineer may also be consulted in this regard. Based upon the result of the tested soil sample, the amount of water soluble sulfate (SO4) was found to be less than 0.001 percent by weight which is considered negligible according to ACI 318, Table 4.3.1. However, due to the site corrosive potential due to proximity to salt or brackish water (Aqua Hedionda Lagoon), and as a minimum,.Portland cement Type II with minimum 28-day concrete compressive strength (f c) of 4000 psi, maximum water cement ratio of 0.50 and adequate protective steel reinforcement cover (or coated reinforcements) should be considered. The actual cement type, maximum water- cementitious materials ratio and minimum concrete compressive strength (f'c), should be reevaluated and confirmed, or revised as appropriate, by the project corrosion/structural engineer. Table 5 below is appropriate based on the pH-Resistivity test result: TABLE 5 [esignSoiITypc[ Gage 118 116 [i4!i 10( 8f I Red brown silty sand II Years to Perforation of Steel Culverts 19 24 30 41 53 64 VIII. WATER QUALITY TREATMENT CONTROL Project storm water management and water quality treatment control planned at the site consists of a combination of bio-retention basins, underground BMP vaults and BMP cistern as shown on the attached Plate 1. Proposed bio-retention facilities are sited along the eastern and western property margins and generally consist of 18 inches of amended soil atop 18 inches of open graded gravel with a perforated pipe at the bottom all enclosed in perimeter CMU walls which connect to the storm drain system. Details for the underground BMP vault and BMP cistern are not yet provided on the current plans. In general, bio-retention and filtration systems consisting of vegetated buffers or strips and self-contained retention areas with impermeable liners on the sides and bottom, special engineered sand filter media and perforated pipe(s) which discharge into an approved storm water drainage facility is acceptable from a geotechnical view. The water treatment should be captured and properly disposed of with no short and long term impacts on the site new building pads, graded and natural surfaces, embankments, bearing and subgrade soils, fill and hackfills, structures, and nearby improvements. Additional and more specific recommendations should be provided by the project geotechnical consultant at the final plans review phase, as necessary. - VINJE & MIDDLETON ENGINEERING, INC. e 2450 Auto Park Way I Escondido, California 92029-1229 0 Phone (760) 743-1214 I Geotechnical Plan Review Update, Proposed Single-Family Residential Page 7 Development, Adams Street, Carlsbad (A.P.N. 206-200-03) November 7, 2013 I IX. CONCLUSIONS & RECOMMENDATIONS I The project most current development plan, reproduced herein as Plate 1, proposes a feasible construction method considering site indicated geotechnical conditions. Geotechnical conditions reported in the referenced report dated August 10, 1998 I (Attachment) remain unchanged, and all conclusions and recommendations provided therein are valid. Conclusions and recommendations provided in the referenced report should be incorporated into the final designs and implemented during the construction I phase except where specifically superseded or amended below. Landslides, faults or significant shear zones are not present at the project property and are not considered a geotechnical factor in planned site development. The study site is not I located near or within the Aiquist - Priolo earthquake fault zone established by the State of California. Liquefaction, seismically induced settlements and soil collapse, will also not be a factor in the development of the project property provided our earthworks and I foundation recommendations are followed. The following are appropriate: 1. The project redevelopment will consist of the construction of a multi-level residential I development as depicted into the enclosed Plate 1. Modest ground alterations are proposed to establish final pad grades and achieve design elevations. I 2. Construction of large graded cut and fill slopes are not proposed in connection with the planned ground modifications and building pad development. Elevation differences between building surfaces will be achieved by the construction of site I and building basement type retaining walls as shown on the enclosed Plate 1. Project anticipated earthwork operations will chiefly consist of basement type I excavations, remedial grading, and backfillingbehind the transition retaining walls. Actual earthwork quantities('nkw at thEiiThe, however, the project I . development may be expected töl5ãlance. Q'-rnj Removals of all existing vegetation, trees, roots, stumps, underground tanks, pipes, conduits and all other unsuitable materials and deleterious matter from the project"-'"pt, I . development areas should be completed as specified in the referenced report. All I 'k'' trash, debris, organic matter and unsuitable materials generated from site clearing efforts should be properly removed and disposed of from the site. Voids created by I the removals of the abandoned underground pipes, tanks and structures should be properly backfilled with compacted fills in accordance with the requirements of this report. The prepared ground should be inspected and approved by the project geotechnical consultant or his designated field representative prior to grading and earthworks. I, "A161vpE A T)t4-7 I 0 LdL. IP ThE iS VINJE & MIDDLETON ENGINEERING, INC. 2450 Auto Park Way I Escondido, California 92029-1229 1 Phone (760) 743-1214 Geotechnical Plan Review Update, Proposed Single-Family Residential Page 8 Development, Adams Street, Carlsbad (A.P.N. 206-200-03) November 7, 2013 The property is generally mantled by shallow deposits of existing loose surficial soil over dense and competent Terrace Deposits and formational rocks. Regrading of the upper compressiblesoil mantle should be completed in order to. construct safe and stable building and improvement surfaces. All excavations, grading, earthworks, foundation constructions and bearing soil preparations should be completed in accord wtthbapter 18 (Soils and Foundations) and Appendix "J" (Grading) of the 2010 California Building Code (CBC), the Standard Specifications for Public Works Construction, City of Carlsbad Grading Ordinances, and requirements of the referenced report (Attachment) and this update transmittal, wherever appropriate and as applicable., ç$ All site existing surficial soils and upper weathered exposures of the underlying Terrace Deposits and formational rocks in the areas of planned new fills, buildings, improvements, drainage facilities, structures, and improvements plus 10 horizontal feet outside the perimeter, where possible and as directed in the field, should be removed (stripped) to the underlying dense and competent Terrace Deposits/formational rocks, as approved in the field, and recompacted. Actual removal (stripping) depths should be established by the project geotechnical consultant at the time of remedial grading operations based on exposed field conditions. Typical removal depths based on available subsurface exploratory excavations are expected to range to nearly 7 feet below the existing ground surfaces. Locally deeper removals may be necessary as directed in the field and should be anticipated. Bottom of all removals should be additionally prepared and recompacted in-place to a minimum depth of 6 inches as directed in the field. All ground steeper than 5:1 receiving fills or backfihls should also be properly benched and keyed as directed in the field. Exploratory test pits excavated in connection with the original study at the indicated locations (see Plate 1) were backfilled with loose and uncompacted deposits. The loose/uncompacted exploratory trench backfill soils shall also be re- excavated and placed back as properly compacted fills in accordance with the requirements of this report. Daylight filling is proposed against the Adams Street road embankment to achieve final design grades. Forthis purpose, the existing roadway embankment should be properly cleared and grubbed, adequately benched out and new fills/wall backfills tightly keyed into the prepared slope as directed in the field. Wall backcut excavations on the order of 12 feet will be needed for portions of the lower level basement wall type constructions. Added care will be required to avoid any undermining or damages to the adjacent structures and improvements to remain, neighboring properties, public right-of-ways, and nearby street improvements due to site excavations, earthwork grading and construction works. VINJE & MJDDLETON ENGINEERING, INC. 1 2450 Auto Park Way Escondido, California 92029-1229 Phone (760) 743-1214 I Geotechnical Plan Review Update, Proposed Single-Family Residential Page 9 Development, Adams Street, Carlsbad (A.P.N. 206-200-03) November 7, 2013 IAll site excavations, removals and trenching should be performed under observations of the project geotechnical engineer. Top of temporary construction I slopes should be adequately set-back from the adjacent property lines, existing foundations and nearby improvements as directed and approved in the field. I Temporary wall backcut and basement excavations developed into the project dense Terrace Deposits and formational rock units may be constructed at near vertical gradients up to a maximum height of less than 10 feet, unless otherwise I noted ordirected in the field. However, limited alternate vertical cut slot-excavations or shoring suppbrt may also become required based on actual field exposures and condition of existing adjacent structures and improvements to remain, as I determined in the field. For limited alternate vertical cut slot excavations, the entire excavation slope should be first laid back at 1:1 gradients maximum. Subsequently, alternate sections may be cut at vertical gradients. For this purpose, limited initial I sections are cut and construction of transition or building basement type retaining walls is completed. Upon approval of the project engineer, vertical sections are then excavated and wall construction in the remaining alternate areas are followed. I Stockpiling the excavated materials or establishing equipment staging areas near the top of excavations should not be allowed. Face of temporary slopes and backcut excavations should be protected from excessive runoff or rainfall. Continuous shoring support may also be required for local exposures where stability of excavations or its potential impacts on the adjacent foundations, neighboring properties, underground facilities or public right-of-way becomes a concern, as determined in the field. In this case, any effective shoring system suitable to the site subsurface conditions such as drilled reinforced cast-in-place piles with concrete or wood lagging, closely spaced cast-in-place mini-piles, or tie-backs with reinforced shot-crete facing may be considered. Specific shoring designs should be provided by the project geotechnical consultant, if becomes necessary. Surficial soils including existing fills, topsoil, and colluvial deposits exposed within upper portions of larger (greater than 5 feet) temporary slopes or wall backcut excavations should be laid back at 1:1 gradients. Elsewhere, project excavations and trenching developed within the site surficial soils may be constructed at near vertical gradients to a maximum total height of 5 feet, unless otherwise directed in the field. Larger excavations and trenching should be laid back at 1:1 gradients or provided with trench shield orshoring support, unless otherwise directed in the field. The exposed wedge of laid back backcut slopes should be properly benched out and new backfills tightly keyed-in as the fill placement progresses. VINJE & MJDDLETON ENGINEERING, INC. 2450 Auto Park Way 0 Escondido, California 92029-1229 Phone (760) 743-1214 S .Geotechnical Plan Review Update, Proposed Single-Family Residential Page 10 Development, Adams Street, Carlsbad (A.P.N. 206-200-03) November 7, 2013 I Site excavations, temporary slope, trenching and wall backcuts will require continuous geotechnical observation during the constructions. Continuous monitoring will be required for the protection of workmen and nearby foundations, I properties and public improvements in the case of the exposed vertical backcuts and temporary slopes. Potential surficial failures, if any identified, should be removed to reestablish safe conditions and hard hats shall be worn at all time. I Construction slopes exposing potentially adverse bedding or fractured conditions or loose fill deposits will be subject to revised recommendations including more gentle gradients, laid back backcuts, smaller alternate slot-excavations or possible 5 shoring. The project contractor shall also obtain appropriate permits, as needed, and conform to the CAL-OSHA and local governing agencies requirements for trenching/open excavations and safety of the workmen during construction. I Excavation permits shall also be obtained from the adjacent property owner(s) or public agencies, if appropriate and applicable. I 9. Ground transition from excavated cut to compacted fills should not be permitted underneath the proposed buildings, structures, and improvements (including paving, utilities and drainage structures), unless otherwise specifically designed. Site I structural foundations, slabs, and improvements should be supported uniformly on compacted fills or founded entirely on competent cut ground exposing dense I undisturbed Terrace Deposits or formational rocks. Transition pads and bearing/subgrade daylight exposures will require special I earthwork mitigation or design methods. The cut portion of the cut-fill transitions plus 5 feet outside the perimeter, where possible and as directed in the field, should be undercut to a sufficient depth to provide for a minimum of 3 feet of compacted I fill mat below rough finish grades, or at least 12 inches of compacted fill beneath the deepest footing(s), whichever is more. Alternatively, foundations straddling over cut-fill daylight lines may be designed as grade beams with heavier reinforcements. I Specific recommendations should be provided by the project geotechnical consultant at the foundation plan review phase. In the improvement areas, there should be a minimum of 12 inches of compacted fill below rough finish subgrade, I as directed in the field. 10. Soil generated from the site removals, stripping, excavations and over-excavations I are generally considered suitable for reuse as site new fills and backfills. However, excavations of clayey surficial deposits are also expected to generate some expansive soils which should be mixed with an abundance of site sandy soils to I .manufacture a very low expansive mixture or adequately buried in deeper fills 3 feet below rough pad grades (or 12 inches below the deepest footing, whichever is more). Expansive clayey soils are also not suitable for wall and trench backfills and I good sandy granular soil should be used for this purpose. 1 I VINJE & MIDDLETON ENGINEERING, INC. 1 2450 Auto Park Way Escondido, California 92029-1229 ° Phone (760) 743-1214 ' Geotechnical Plan Review Update, Proposed Single-Family Residential Page 11 Development, Adams Street, Carlsbad (A.P.N. 206-200-03) November 7, 2013 I Import soils, if used, should be non-corrosive, very low expansive sandy granular soils (100% passing 1-inch sieve, more than 50% passing #4 sieve and less than 18% passing #200 sieve with expansion index less than 20), inspected, tested as I necessary, and approved by the project geotechnical consultant priorto delivery to the site. Import soils should also meet or exceed the design parameters given in I . the following sections. Fill and backfill materials, processing, placement, compaction procedures and requirements, as well as engineering observations and testing protocol will remain I the same as specified in the referenced report. Uniform bearing and subgrade soil conditions should be constructed at the site by the grading operations. Site fills I should be adequately processed, thoroughly mixed, moisture conditioned to slightly above (2%-3%) the optimum moisture levels as directed in the field, placed in thin (8 inches maximum) uniform horizontal lifts and mechanically compacted with heavy I construction equipments to a minimum 90% of the corresponding laboratory maximum dry density per ASTM D-1557, unless otherwise specified. The upper 12 inches of subgrade soils below the base layer under roadway asphalt paving I surfaces should also be compacted to minimum 95% compaction levels. Shallow stiff stem wall/stepped and spread pad foundations may be considered for I the support of the proposed buildings and structures. Shallow foundations should be uniformly founded on undisturbed competent formational rocks or well compacted fills as approved in the field by the project geotechnical consultant. I Continuous strip concrete foundations should be sized at least 15 inches wide and 18 inches deep. Spread pad footings, if any, should be at least 30 inches square I and 18 inches deep and structurally interconnected with the continuous strip footings with grade beams. Grade beams should be a minimum of 12 inches wide by 18 inches deep. Footing depths are measured from the lowest adjacent ground I ' surface, not including the sand/gravel layer beneath floor slabs. Exterior continuous footings should enclose the entire building perimeter. I Continuous interior and exterior foundations should be reinforced with a minimum of 445 reinforcing bars. Place 2#5 bars 3 inches above the bottom of the footing and 245 bars 3 inches below the top of the footing. Grade beams should also be I reinforced with minimum 244 bars top and bottom. Reinforcement details for spread pad footings should be provided by the project architect/structural engineer. I Foundations can only be constructed on level surfaces and should be stepped in sloping ground conditions (more than 1 unit vertical in 10 units horizontal or 10%), as necessary. Top and bottom of stepped foundations shall be level, Individual I steps in continuous footings shall not exceed 18 inches in height and the slope of a series of such steps shall not exceed I unit vertical to 2 units horizontal (SO%) 1 I VINJE & MIDDLETON ENGINEERING, INC. 2450 Auto Park Way ° Escondido, California 92029-1229 ' Phone (760) 743-1214 I ' Geotechnical Plan Review Update, Proposed Single-Family Residential Page 12 Development, Adams Street, Carlsbad (AP.N. 206-200-03) November 7, 2013 I unless otherwise specified. The steps, and foundation reinforcement requirements shall be designed by the project structural consultant and detailed on the project structural drawings. The local effects due to the discontinuity of the steps shall also I be considered in the design of foundations as appropriate and applicable: Adequate setback or deepened foundations shall be required for all foundations I constructed on or nearthe top of descending slopes to maintain minimum horizontal distances to daylight or adjacent slope face. There should be minimum 7 feet horizontal setback from the bottom outside edge of the footing to daylight for I foundations, and at least 10 feet to daylight for swimming pools and more sensitive structures which cannot tolerate minor movements. All interior slabs should be a minimum of 5 inches in thickness reinforced with #4 - reinforcing bars spaced 18 inches on center each way placed near the slab mid- height. Slabs should be underlain by at least 4 inches of clean sand (SE 30 or I greater) which is provided with a well performing moisture barrier/vapor retardant (minimum 15-mil Stego) placed mid-height in the sand. Alternatively, a 4-inch thick base of compacted 1A-inch clean aggregate provided with the vapor barrier I (minimum 15-mil Stego) in direct contact with (beneath) the concrete may also be considered provided a concrete mix which can address bleeding, shrinkage and I curling are used. Provide re-entrant corner reinforcement for all interior slabs per Plate 8 of the I referenced report. Interior slabs should also be provided with "softcut" contraction/control joints consisting of sawcuts spaced 10 feet on center maximum each way. Cut as soon as the slab will support the weight of the saw, and operate I without disturbing the final finish which is normally within 2 hours after final finish at each control joint location or 150 psi to 800 psi. The softcuts should be a minimum of 1-inch in depth but should not exceed 1¼-inches deep maximum. Anti-ravel skid I Avoid plates should be used and replaced with each blade to avoid spalling and raveling. wheeled equipment across cuts for at least 24 hours. I * Foundation trenches and slab subgrade soils should be inspected and tested for proper moisture and specified compaction levels and approved by the project geotechnical consultant prior to the placement of concrete. I 13. Post construction settlement after completion of grading works as specified herein, is not expected to exceed approximately 1-inch and should occur below the heaviest loaded footing(s). The magnitude of post construction differential I settlements of site fill deposits as expressed in terms of angular distortion is not anticipated to exceed V2-inch between similar elements in a 20-foot span. I I I VINJE & MIDDLETON ENGINEERING, INC. • 2450 Auto Park Way ° Escondido, California 92029-1229 0 Phone (760) 7434214 ' Geotechnical Plan Review Update, Proposed Single-Family Residential Page 13 Development, Adams Street, Carlsbad (A.P.N. 206-200-03) November 7, 2013 I 14. Soil design parameters including bearing andlateral earth pressures, will remain the same as specified in the referenced reports (see Attachment). However, an additional seismic force due to seismic increment of earth pressure may also be I appropriate in the project designs in case of building walls with greater than 6-feet soil differential on each side or retaining walls 12 feet or taller, as determined by the project design consultant. A seismic lateral inverted triangular earth pressure of 21 I pcf(EFP) acting at 0.6H (H is the retained height) above the base of the wall should also be considered, if appropriate and applicable. The seismic lateral earth pressure should be considered in addition to the specified static earth and I surcharge (due to nearby foundations and vehicular traffic loading) pressures. 15. All exterior slabs (walkways, patios, pool decks, etc.) supported on very low I expansive subgrade soils should be a minimum of 4 inches in thickness, reinforced with 6X6-10X10 welded wire mesh carefully placed near the slab mid-height. The subgrade soils should be compacted to minimum 90% compaction levels at the time I of fine grading and before placing the slab reinforcement. Reinforcements lying on subgrade will be ineffective and shortly corrode due to lack I of adequate concrete cover. Reinforcing bars should be correctly placed extending through the construction joints tying the slab panels. In construction practices, where the reinforcements are discontinued or cut at the construction joints, slab 1 panels should be tied together with minimum 18 inches long #3 dowels (dowel baskets) at 18 inches on centers maximum placed mid-height in the slab (9 inches I on either side of the joint). Provide "tool joint" or "softcut" contraction/control joints spaced 10 feet on center ' (not to exceed 12 feet maximum) each way. The larger dimension of any panel shall not exceed 125% of the smaller dimension. Tool or cut as soon as slab will support weight, and can be operated without disturbing the final finish which is I normally within 2 hours after final finish at each control joint location or 150 psi to 800 psi. Tool orsoftcuts should be minimum of I-inch but should not exceed 1¼- inch deep maximum. In case of softcut joints, anti-ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. Avoid wheeled equipments across cuts for at least 24 hours. ' Joints shall intersect free-edges at a 900 angle and shall extend straight for a minimum of 11/2 feet from the edge. The minimum angle between any two intersecting joints shall be 800. Align joints of adjacent panels. Also, align joints in ' attached curbs with joints in slab panels. Provide adequate curing using approved methods (curing compound maximum coverage rate = 200 sq. ft./gal.). I I I VINJE & MIDDLETON ENGINEERING, INC. 2450 Auto Park Way ° Escondido, California 92029-1229 0 Phone (760) 743-1214 I Geotechnical Plan Review Update, Proposed Single-Family Residential Page 14 Development, Adams Street, Carlsbad (AP.N. 206-200-03) November 7, 2013 I All exterior slab designs should be confirmed in the final as-graded compaction report. Subgrade soils should be tested for proper moisture and specified compaction levels and approved by the project geotechnical consultant prior to the I placement of concrete. - Specific pavement designs can best be provided at the completion of rough grading I based on R-value tests of the actual finish subgrade soils; however, the following structural sections may be considered for initial planning phase cost estimating I purposes only (not for construction): * A minimum section of 4 inches asphalt on 6 inches Caltrans Class 2 aggregate base or the minimum structural section required by City of Carlsbad, whichever I is more, may be considered for the on-site asphalt paving surfaces outside the private and public right-of-way. 'The Class 2 aggregate base shall meet or exceed the requirements set forth in the current California Standard I Specification (Caltrans Section 26-1.02). In the areas where the longitudinal grades exceed 10%, 1/2-inch asphalt should be added to the design asphalt thickness for each 2% increase in grade or portions thereof. PCC paving should I be considered for longitudinal grades greater than 15% maximum. Actual design will also depend on the design TI and approval of the City of Carlsbad. 1 * Base materials should be compacted to a minimum 95% of the corresponding maximum dry density (ASTM D-1557). Subgrade soils beneath the asphalt paving surfaces should also be compacted to a minimum 95% of the I corresponding maximum dry density-within the upper 12 inches. Residential PCC driveways and parking supported on very low expansive I (expansion index less than 20) granular subgrade soils should be a minimum 51A inches in thickness, reinforced with #3 reinforcing bars at 18 inches on centers each way placed at mid-height in the slab. Subgrade soils beneath the PCC driveways I and parking should also be compacted to a minimum 90% of the corresponding maximum dry density. 1 In the areas where longitudinal grades exceed 15%, provide minimum 8 inches wide by 8 inches deep pavement anchors dug perpendicularto the pavement longitudinal I profile into the approved subgrade at each 25-feet interval maximum. The pavement anchors should be poured monolithically with the concrete paving surfaces. I Provide "tool joint" or "softcut" contraction/control joints spaced 10 feet on center (not to exceed 15 feet maximum) each way. The larger dimension of any panel I shall not exceed 125% of the smaller dimension. Tool or cut as soon as the slab will support the weight and can be operated without disturbing the final finish which is normally within 2 hours after final finish at each control joint location or 150 psi to I I VINJE & MIDDLETON ENGINEERING, INC. 2450 Auto Park Way Escondido, California 92029-1229 0 Phone (760) 743-1214 Geotechnical Plan Review Update, Proposed Single-Family Residential Page 15 Development, Adams Street, Carlsbad (A.P.N. 206-200-03) November 7, 2013 800 psi. Tool or softcuts should be a minimum of 1-inch in depth but should not exceed 1 74-inches deep maximum. In case of softcut joints, anti-ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. Avoid wheeled equipments across cuts for at least 24 hours. Joints shall intersect free edges at a 90° angle and shall extend straight for a minimum of 11/2 feet from the edge. The minimum angle between any two intersecting joints shall be 800. Align joints of adjacent panels. Also, align joints in attached curbs with joints in slab panels. Provide adequate curing using approved method (curing compound maximum coverage rate = 200 sq. ft./gal.). The pool and spa excavations are expected to chiefly expose dense undisturbed Terrace Deposits with very low expansive potential. Project natural undisturbed Terrace Deposits will adequately support the planned new pool and spa, however, pool/spa designs and construction should be completed based on very low expansive soils (expansion index 20) and lateral earth pressures provided in this report. The pool and spa shells should also be provided with a minimum 15 inches wide by 18 inches deep perimeter grade beam reinforced with minimum 244 bars top and bottom around the top of the concrete shell. Pool/spa shell thickness and reinforcements per structural details. Deepened pool wall foundations shalt be required for the southern outside pool wall(s) planned on the adjacent descending slope to provide a minimum of 10 feet horizontal distance or set back to daylight. Reinforcement for deepened footings should be provided by the project architect/structural engineer. A well-constructed back drainage system should be installed behind all site and building basement type retaining walls at the project site. The wall back drainage system should consist of a minimum 4-inch diameter, Schedule 40 (SDR 35) perforated pipe surrounded witha minimum of 11,4 cubic feet per foot of 1/4-crushed rocks (12 inches wide by 18 inches deep) installed at the depths of the wall foundation level and wrapped in filter fabric (Mirafi 140-N). If Caltrans Class 2 permeable aggregate is used in lieu of the crushed rocks, the filter fabric can be deleted. The wall back drain should be installed at suitable elevations to allow for adequate fall via a non- perforated solid pipe (Schedule 40 or SDR 35) to an approved outlet. Protect pipe outlets where they daylight or graded or natural surfaces. All subdrain pipes and outlet locations should be shown on the final grading or site plan. A typical wall back drain system is depicted on the Plate 9 of the referenced report (see Attachment). Provide appropriate waterproofing where applicable as indicated on the pertinent project construction plans. I VINJE & MIDDLETON ENGINEERING, INC. 0 2450 Auto Park Way 0 Escondido, California 92029-1229 0 Phone (760) 743-1214 Geotechnical Plan Review Update, Proposed Single-Family Residential Page 16 Development, Adams Street, Carlsbad (A.P.N. 206-200-03) November 7, 2013 I 20. Control of site surface drainage and potential for development of post construction subsurface water caused by surface water infiltrations is one of the most significant geotechnical factors with regards to the future performance of the new building site I with lower basement type level and associated improvement and structures. Surface flow, run-off drainage and subsurface water should not impact graded surfaces, saturate site fills, wall backfifls, bearing and subgrade soils, or cause I erosion. Drainage structures and erosion control measurements should be provided at as discussed in the referenced report and shown on the project grading and drainage improvement plans. I . 21. Open or backfilled trenches parallel with a footing shall not be below a projected plane having a downward slope of 1-unit vertical to .2 units horizontal (50%) from a I line 9 inches above the bottom edge of the footing, and not closer than 18 inches from the face of such footing. I 22. Where pipes cross under footings, the footings shall be specially designed. Pipe sleeves shall be provided where pipes cross through footings or footing walls, and sleeve clearances shall provide for possible footing settlement, but not less than 1- I inch all around the pipe. X. GEOTECHNICAL ENGINEER OF RECORD (GER) I Vinje & Middleton Engineering, Inc. is the geotechnical engineer of record (GER) for providing a specific scope of work or professional service under a contractual agreement ' unless it is terminated or canceled by either the client or our firm. In the event a new geotechnical consultant or soils engineering firm is hired to provide added engineering I services, professional consultations, engineering observations and compaction testing, Vinje & Middleton Engineering, Inc. will no longer be the geotechnical engineer of the record. Project transfer should be completed in accordance with the California Geotechnical Engineering Association (CGEA) Recommended Practice for Transfer of I Jobs Between Consultants. The new geotechnical consultant or soils engineering firm should review all previous geotechnical documents, conduct an independent study, and provide appropriate confirmations, revisions or design modifications to his own satisfaction. The new geotechnical consultant or soils engineering firm should also notify in writing Vinje & Middleton Engineering, Inc. and submit proper notification to the City of Carlsbad for the assumption of responsibility in accordance with the applicable codes and standards (1997 UBC Section 3317.8). I I VINJE & MIDDLETON ENGINEERING, INC. 2450 Auto Park Way 0 Escondido, California 92029-1229 Phone (760) 743-1214 I Geotechnical Plan Review Update, Proposed Single-Family Residential Page 17 Development, Adams Street, Carlsbad (A.P.N. 206-200-03) November 7, 2013 I XI. LIMITATIONS The conclusions and recommendations provided herein have been based on all available I data obtained from the review of pertinent geotechnical documents, current site observations, shallow sampling and added laboratory testing, as well as our experience with the soils and bedrock materials located in the general site areas. I Of necessity we must assume a certain degree of continuity between available exploratory excavations and/or natural exposures. It is necessary, therefore, that all observations, I conclusions, and recommendations are verified during the grading operation. In the event discrepancies are noted, we should be contacted immediately so that an inspection can be made and additional recommendations issued if required. The recommendations made I in this report are applicable to the site at the time this report was prepared. It is the responsibility of the owner/developer to ensure that these recommendations are carried out in the field. I It is almost impossible to predict with certainty the future performance of a property. The future behavior of the site is also dependent on numerous unpredictable variables, such as earthquakes, rainfall, and on-site drainage patterns. The firm of VINJE & MIDDLETON ENGINEERING, INC., shall not be held responsible for I changes to the physical conditions of the property such as addition of fill soils, added cut slopes, or changing drainage patterns which occur without our inspection or control. I The property owner(s) should be aware that the development of cracks in all concrete surfaces such as floor, slabs and exterior stucco is associated with normal concrete shrinkage during the curing process. These features depend chiefly upon the condition of I concrete and weather conditions at the time of construction and do not reflect detrimental ground movement. Hairline stucco cracks will often develop at window/door corners, and floor surface cracks up to 1/8-IflCh wide in 20 feet may develop as a result of normal I concrete shrinkage (according to the American Concrete Institute). This report is issued with the understanding that the owner or his representative is I responsible for ensuring that the information and recommendations are provided to the project architect/structural engineer so that they can be incorporated into the plans. Necessary steps shall be taken to ensure that the project general contractor and I subcontractors carry out such recommendations during construction. The project geotechnical engineer should be provided the opportunity for a general review of the projects final design plans and specifications in order to ensure that the recommendations provided in this report are properly interpreted and implemented. The project geotechnical engineer should also be provided the opportunity to field verify the foundations prior to placing concrete. If the project geotechnical engineer is not provided the opportunity of making these reviews, he can assume no responsibility for misinterpretation of his recommendations. VINJE & MIDDLETON ENGINEERING, INC. 2450 Auto Park Way Escondido, California 92029-1229 0 Phone (760) 743-1214 Geotechnical Plan Review Update, Proposed Single-Family Residential Page 18 Development, Adams Street, Carlsbad (A.P.N. 206-200-03) November 7, 2013 I This report should be considered valid for a period of one year and is subject to review by our firm following that time. In case of plan revisions including changes in the final pad size, graded embankments, actual building and improvement locations, lines and grades, I and final elevations, this report should be reviewed and updated by this office for review comments and additional recommendations based on the plan changes, as appropriate. I We appreciate this opportunity to be of service to you. If you have any questions or need clarification, please do not hesitate to contact the undersigned. Reference to our Job #13-234-P will help to expedite our response to your inquiries. I VINJE & MIDDLETON ENGINEERING, INC. I S.MAhdi S. Shariat -2M No GE 31885 [ai "m - Ep.12/31i14 Steven J. Meizer CEG #2362 Distribution: Addressee (5, e-mail) Howard Anderson + Associates Arch No. 2362 CER1iFJE EXIGILW'ING GEOLOGIST EXRth Jaime Bernal (e-mail) I VINJE & MIDDLETON ENGINEERING, INC. 2450 Auto Park Way Escondido, California 92029-1229 0 Phone (760) 743-1214 I REFERENCES - Annual Book of ASTM Standards, Section 4 - Construction, Volume 04.08: Soil and I Rock (I); 0420-05876,2012. - Annual Book of ASTM Standards, Section 4 - Construction, Volume 04.09: Soil and Rock (II); D 5876- Latest, 2012. I - Highway Design Manual, Caltrans. Fifth Edition. - Corrosion Guidelines, Caltrans, Version 1 .0, September 2003. I - California Building Code, Volumes 1 & 2, International Code Council, 2010. - "Green Book" Standard Specifications for Public Works Construction, Public Works Standards, Inc., BNi Building News, 2003 Edition. I - California Department of Conservation, Division of Mines and Geology (California Geological Survey), 1997, Guidelines for Evaluating and Mitigating Seismic Hazards in California, DOG Special Publication 117, 71p. I - California Department of Conservation, Division of Mines and Geology (California Geological Survey), 1986 (revised), Guidelines for Preparing Engineering Geology - Reports: DMG Note 44. - California Department of Conservation, Division of Mines and -Geology (California Geological Survey), 1986 (revised), Guidelines to Geologic and Seismic Reports: DMG Note 42. - EQFAULT, Ver. 3.00, 1997, Deterministic Estimation of Peak Acceleration from I Digitized Faults, Computer Program, T. Blake Computer Services and Software. - EQSEARCH, Ver 3.00, 1997, Estimation of Peak Acceleration from California I Earthquake Catalogs, Computer Program, T. Blake Computer Services and Software. p - Tan S.S. and Kennedy, M.P., 1996, Geologic Maps of the Northwestern Part of San Diego County, California, Plate(s) I and 2, Open File-Report 96-02, California Division of Mines and Geology, 1:24,000. I - 'Proceeding of The NCEER Workshop on Evaluation of Liquefaction Resistance Soils," Edited by T. Leslie Youd and Izzat M. Idriss, Technical Report NCEER-97-0022, Dated December 31, 1997. "Recommended Procedures For Implementation of DMG Special Publication 117 I Guidelines ForAnalyzing and Mitigation Liquefaction in California," Southern California Earthquake Center; USC, March 1999. I I REFERENCES (continued) - "Soil Mechanics," Naval Facilities Engineering Command, DM 7.01. - "Foundations & Earth Structures," Naval Facilities Engineering Command, DM 7.02. - "Introduction to Geotechnical Engineering, Robert D. Holtz, William D. Kovacs. - "Introductory Soil Mechanics and Foundations: Geotechnical Engineering," George F. Sowers, Fourth Edition. "Foundation Analysis and Desigh," Joseph E. Bowels. - Caterpillar Performance Handbook, Edition 29, 1998. - Jennings, C.W., 1994, Fault Activity Map of California and Adjacent Areas, California Division of Mines and Geology, Geologic Data Map Series, No. 6. - Kennedy, M.P., 1977, Recency and Character of Faulting Along the Elsinore Fault Zone in Southern Riverside County, California, Special Report 131, California Division of Mines and Geology, Plate 1 (East/West), 12p. - Kennedy, M.P. and Peterson, G.L., 1975, Geology of the San Diego Metropolitan Area, California: California Division of Mines and Geology Bulletin 200, 56p. - Kennedy, M.P. and Tan, S.S., 1977, Geology of National City, Imperial Beach and Otay Mesa Quadrangles, Southern San Diego Metropolitan Area, California, Map Sheet 24, California Division of Mines and Geology, 1:24,000. - - Kennedy, M.P., Tan, S.S., Chapman, R.H., and Chase, G.W., 1975, Character and Recency of Faulting, San Diego Metropolitan Areas, California: Special Report 123, 33p. - "An Engineering Manual For Slope Stability Studies," J. M. Duncan, A. L. Buchignani and Marius De Wet, Virginia Polytechnic Institute and State University, March 1987. - "Procedure to Evaluate Earthquake-Induced Settlements in Dry Sandy Soils," Daniel Pradel, ASCE Journal of Geotechnical & Geoenviron mental Engineering, Volume 124, #4, 1998. - "Minimum Design Loads For Buildings and Other Structures," ASCE 7-05, American Society of Civil Engineers. I I 1 I II A' Ai / I ii I II II I/i '1I I I i 411 ar -I I C66.60 6552 / IFt ojo IC 67.80 4I / / iL6Z22 CO /1 7 110 TES. I. 77175 is NOT A BOUNDARY SURVEY. BOUNDARY INFORU.4I1CW PER RECORD DA TA. 2 THE PROPERTY BOUNDARY IIIFORMA7IOU SHOW HEREON REFLECTS DIMENSIONS PER ROS 75052 EASEMENT NOTES- AA AN EASEMENT FOR SPOOR PIPELINE AND INCIDENTAL PURPOSES RECORDED MARCH 5, 7906 AS INSIRUMENT Na 47720 OF OFFICIAL RECORDS. AN EASEMENT FOR SEllER PIPELINE AND I1ICIIIENTAL PURPOSES RECORDED DECEMBER 7. 2007 AS I/I57SIJMENT Mo. 07-767779 Of LES7CIAL RECORDS PROPOSES 5 FOOT (OREIVCABLE OFFER OF DEDICATION TO INC CITY OF CARLSBAD. MEAl! HIGH ODE LINE (ELY VA 7101! 2.071 UNIT ON 700' FEET FROM MEAN ICON ODE LINE OVERFLOW RISER CIIU WALL VICINITY MAP GEOTECHNICAL LEGEND 900 Test Trench (7/1/1998) I Geologic Cross-Section af Road Fill Qt Terrace Deposit TS Formational Rock TALL 70' OF Al/GilDED SC/I IS' OF 00TWL CC/OilEr TO STORM ERAFI OMB?: CAROLINE & NEIL MARlIN 7078 SHAOEIREE DRIVE SAN MARCOS CA 92018 SITE ADDRESS: ADAMS SIREET CARLSBAD, CA 92008 A.S9Y'6 PAPB.. Ak: 200200-DJ LEG4L CESOWTOV, THE I4ESTERLT 75 FEET Of DIE EASTERLY 225 FEET OF LOT DIN BLOCK 'O OF BELLA VISTA, IN THE CITY OF CARLSBAD, COUNTY OF SAN DIEGO, STAlE OR CAUFORIAIA. ACCORDING TO MAP THEREON Na 2752 FILED MARCH 1, 7929 IN THE OFFICE OF THE COUNTY RECORDER OF SAt! 0/EGO COUNTY, ETA/SOLED CROSS ON HEADWALL 0 CORNER OF INTERSECTION OF PARK DRIVE AND HILLSIDE DRIVE IN THE CITY ON CARLSBAD. ELEV. 78.572' OAIIJM: USC 9 G.S. E4R1M4tJR( clffi.NTITES: WT: GY FLL CY E2PQT/ CY r PLATE I. V&M JOB #13-234--P j ,'IN 101 1.7-0,76 ID/101A GOON PRELIMINARY GRADING PLAN C ADAM .c c'TRFFT SCAflS'.' 1•' = on, ci API): 20200-04 - BIOREIVIII0.7 BA / rOILONALNIlOIl BASIN 5.7 rW 65.0 I / FG 5Z29 451- 4ZO2 ND3UI 75,ii J3 m"4 45 wY2 J tTj2,2 /Ty- ---- IE 46.3 Qt OUND pl__54 Z 101V ll/ M TOR COURT ' r ii floo 4 [UPP P OPOSED I' (t ~'A T-3 / 6' I RS!DENGE LIMIT'S CF ROOF L ° 1 278 BLOCJ '2)' T— WA LIMITS OF UFER LIMITS OF IFFER OEC4E / . / I/f , / PAD 36.3 II f Qt T-2 - / I 1 Qt 65. -=•==-=-=__ '°. - •• Ts ' / 4 ALLWOET36.52 I I - P cis - 936.7 i 5ORES BASIN 11/1,11P 2152 LEDEPe STANOATE7AIOTES STIIBi2 PROPERTY BOUNDARY - - - - EYJSITND CURIO/JR —Il5 PROPOSED CONTOUR EXISITNE ELEVAITCI! 0 7755 PROPOSED LIE VA TIDY ABOVE ERASE ELEVATiON BUILDING FOOTPRINT BASEMENT FOOTPRINT EXISTING RETAINING WALL PROPOSED RETAINING WALL 'ao LI/illS OF AC 1, DAYLIGHT LANE SHIRE 7071771/N BASIN DIREC 77011 OF FLOW - PVC 51CR/A DRAIli PIPE CHANNEL 0018! (BY NOS) 17' 014 DRAIN IIILET (BY H052 = o= = I?' SO SPAIN INLET (BY HOS) CLEANS/IT (BY HITS') WALL/FOUIIOA 71011 SIJ800AIN (Br OTHERS) - - - - - - - - - - - - - - - - - - cJOLOWC C©=ICTWN PROPOSED PROPOSED 60--, GARAGE PROPOSED DWELLING WALL BAC~KIDRAI PROPOSED WALL BACKDRAIN POOL 30 - - - TRACi D1PO1[T (tJ - 20 -F----------- FORTA WNAL ROCA () -- - 110 -- I SCALE: I" = 20' ( PLATE 2 t V&M JOB #13-234--P TcLNTPPR TNTI — Job #98257P 2450 Auto Park Way I Escondido, California 92029-1229 Phone (760) 743-1214 August 10, 1998 Fax (760) 739-0343 I Mr. Gene Huber I The Prudential California Realty 523 Encinitas Boulevard, Suite 100 Encinitas, California 92024 1 Preliminary Soil and Geotechnical Investigation, Parcels A, B, C, I APN #260-20-03. 04 and 05, Adams Street, Carlsbad. California Pursuant to your request, Vinje & Middleton Engineering, Inc. has completed the attached I investigation of soils and geotechnical conditions at the subject site. The following report summarizes the findings of our subsurface investigation, including I field and laboratory test results, analyses and conclusions, and provides recommendations for the site development as understood. From a geotechnical engineering standpoint, it I is our opinion that the site is suitable for the proposed' development provided the recommendations presented in this report are incorporated into the design and construction of the project. I The conclusions and recommendations provided in this study are consistent with the site geotechnical conditions and are intended to aid in preparation of final plans and allow I more accurate estimates of development costs. Thank you for choosing Vinje & Middleton Engineering, Inc. If you have any questions I concerning this report, please do not hesitate to call us. Reference to our Job # 98-257-P will help to expedite our response to your inquiries. We appreciate this opportunity to be of service to you. 1 VINJE & MIDDLETON ENGINEERING, INC. ____ GE #863 P.! I RMV/jt I I Preliminary Soil and Geotechnical Investigation Parcels A, B, C APN #260-20-03, 04 and 05. Adams Street Carlsbad, California August 10, 1998 Prepared For: Mr. Gene Huber The Prudential California Realty 523 Encinitas Boulevard, Suite 100 Encinitas, California 92024 TABLE OF CONTENTS PAGE NO. I I INTRODUCTION ..................................................i If. SITE DESCRIPTION ...............................................I III PROPOSED DEVELOPMENT ........................................I IV. SITE INVESTIGATION .............................................2 V. FINDINGS .......................................................2 Earth Materials ................................................2 Groundwater ..................................................2 Faults/Seismicity ..............................................3 Geologic Structure/Slope Stability ................................4 Geologic Hazards ..............................................5 Laboratory Testing/Results ......................................5 VI. CONCLUSIONS ...................................................7 VII. RECOMMENDATIONS .............................................8 Grading and Earthworks ........................................8 Foundations and Slab-On-Grade Floors ..........................11 Exterior Concrete SlabslFlatworks ...............................12 Soil Design Parameters .........................................13 Asphalt Pavement Design ......................................14 General Recommendations .....................................15 VIII. LIMITATIONS ...................................................17 TABLES FaultZone ..........................................................i SoilType ...........................................................2 Maximum Dry Density and Optimum Moisture Content .....................3 Moisture-Density Tests (Undisturbed Chunk Samples) .....................4 Direct Shear Test ......................................................5 Expansion Index Test .................................................6 Removals and Over-Excavations .......................................7 PLATES Geotechnical Map .. .. . ........... ........................ ............ I Test Trench Logs . .. ...............,. ...............................2-5 Fault-Epicenter Map . . . . . .. ......... .., . . . ............. ...... 6 Geologic Cross-Section .......................,. .. . . .... .... 7 Isolation Joints and Re-Entrant Corner Reinforcement . . .... ... . 8 Retaining Wall Drain Detail .. . ........... . .. . 9 Preliminary Soil and Geotechnical Investigation Parcels A, B, C . APN #260-20'03, 04 and 05 Adams Street, Escondido, California INTRODUCTION The property investigated in this work is divided into three similar parcels. Parcel "N'- 4475 Adams Street, Parcel "B"- 4485 Adams Street, and Parcel "C"- 4495 Adams Street. They are contiguous hillside lots on the south side of Adams Street and adjacent to the Aqua Hedionda Lagoon in the City of Carlsbad. Consequently, the property location is I shown on the Geotechnical Map, Plate 1. I We understand the three parcels are planned for individual residential development and that Parcel B, will be developed first. Cut/fill grading is proposed to create level building surfaces for the residence and associated structures. Consequently, the purpose of this I study was to determine the general, site geologic and soil conditions and their influence on planned improvements. I . Test Trenches were excavated, and soil sampling and testing were performed in connection with this investigation, which resulted in the development recommendations provided herein. SITE DESCRIPTION The subject parcels are rectangular shaped and encompass hillside terrain characterized by gentle slopes that descend southward to the shoreline of the Aqua Hedionda Lagoon. The property is in a natural condition overall and is mantled with wild grasses, weeds and scattered bush. Fill deposits located along the upper reaches of the properties are likely derived from the grading activities for the construction of Adams Street, and are shown on Plate 1. Site drainage sheet flows southward over project terrain with minor scouring in evidence. Groundwater was not encountered in project test excavations. III; PROPOSED DEVELOPMENT The three parcels studied 'during this investigation are planned for individual residential development. Parcel B is planned to be developed first and Parcels A and C at a later date. We understand that cut-fill grading is planned to create level building surfaces for the residence and associated structures on Parcel B. Retaining walls will be utilized along the upper (north) margin. However, details of the proposed grading and foundation configuration are unknown. VINJE & MIDDLETON ENGINEERING. INC. 0 2450 Auto Park Way 0 Escondido, California 92029-1229 0 Phone (760) 743-1214 I PRELIMINARY SOIL AND GEOTECHNICAL INVESTIGATION PAGE 2 PARCELS A,B,C, ADAMS STREET, CARLSBAD AUGUST 10, 1998 Detailed building plans were also not available for review at this time. SITE INVESTIGATION The geotechnical conditions at the project lots were determined from geologic mapping of I available surface exposures and the excavation of 8 test trenches dug with a tractor- mounted backhoe. The trenches were logged by our project geologist who also retained ' representative soil/rock samples for laboratory testing. Test results are presented in a following section. The test trench locations are shown on Plate I and the logs of the trenches are attached to this report as Plates 2-5. FINDINGS Study properties are chiefly natural hillside terrain underlain by sandstone bedrock units that are mantled by younger surface soils. A. Earth Materials The project site is underlain by tertiary to quaternary aged marine sedimentary sandstone deposits.. The older tertiary aged formational bedrock unit which is exposed in the lower reaches of the site is an off-white colored, fine to coarse grained, cemented, massive sandstone. Overlying this formational bedrock unit is the younger, quaternary aged terrace deposit that is tan to light brown colored, fine to medium grained sandstone. Loose sand deposits also occur within the upper terrace deposit, as exposed in test trench 1-7 (see plate 5). Colluvial and topsoil materials mantle the terrace deposit and consist of brown colored, silty sands to sandy clays that are in a loose to stiff condition. Fill soils comprised of brown colored, silty sands, are found along Adams Street and are in a dry and loose condition. Details of the earth materials at the project are given on the enclosed Plates2-9. Laboratory tests are summarized in a following section. B. Groundwater Groundwater was not encountered in our test trench excavations to the depths explored. However, like all hillside properties, the proper control of surface and near surface drainage is a critical element in the continued stability of the property. I VINJE & MIDDLETON ENGINEERING. INC. 2450 Auto Park Way ° Escondido, California 92029-1229 Phone (760) 743-1214 PRELIMINARY SOIL AND GEOTECHNICAL INVESTIGATION PAGE 3 PARCELS A,B,C, ADAMS STREET, CARLSBAD AUGUST 10, 198 C. Faults/Seismicity Faults or significant shear zones are not indicated on or near proximity to the project site. As with most areas of California, the San Diego region lies within a seismically active zone; however, coastal areas of the county are characterized by low levels of seismic activity relative to inland areas to the east. During a 40-year period (1934-1974), 37 earthquakes were recorded in San Diego coastal areas by the California Institute of Technology. None of the recorded events exceeded a Richter magnitude of 3.7, nor did any of the earthquakes generate more than modest ground shaking or significant damages. Most of the recorded events occurred along various offshore faults which characteristically generate modest earthquakes. Historically, the most significant earthquake events which affect local areas originate along well known, distant fault zones to the east and the Coronado Bank Fault to the-west. Based upon available seismic data, compiled from California Earthquake Catalogs, the most significant historical event in the area of the study site occurred in 1800 at an estimated distance of 14 miles from the project area. This event, which is thought to have occurred along an off-shore fault, reached an estimated magnitude of 6.5 with estimated bedrock acceleration values of 0.20g at the project site. The following list represents the most significant faults which commonly impact the region. Estimated ground acceleration data compiled from Digitized California Faults (Computer Program EQ Fault Ver. 2:01) typically associated with the fault is also tabulated. TABLE I MAXIMUM• • PROBABLE. PAUL T ZONE DISTANCE FROM SITE ACCELERATION (R;H.). Elsinore Fault j 27 miles 0.068g San Jacinto Fault 50 miles 0.034g Coronado Bank Fault 18 miles 0.0819 The location of significant faults and earthquake events relative to the study site are depicted on a Fault - Epicenter Map attached to this report as Plate 6. More recently, the number of seismic events which affect the region appears to have heightened somewhat. Nearly 40 earthquakes of magnitude 3.5 or higher VINTE & MIDDLETON ENGINEERING, INC. 2450 Auto Park Way * Escondido, California 92029-1229 Phone (760) 743-1214 I I I I I I I I I PRELIMINARY SOIL AND GEOTECHNICAL INVESTIGATION PAGE 4 PARCELS A,B,C, ADAMS STREET, CARLSBAD AUGUST 10, 1998 have been recorded in coastal regions between January 1984 and August 1986. Most of the earthquakes are thought to have been generated along offshore I faults. For the most part, the recorded events remain moderate shocks which typically resulted in low levels of ground shaking to local areas. A notable exception to this pattern was recorded on July, 13, 1986. An earthquake of I magnitude 5.3 shook County coastal areas with moderate to locally heavy ground shaking resulting in $700,000 in damages, one death, and injuries to 30 people. The quake occurred along an offshore fault located nearly 30 miles southwest of I Oceanside. I A series of notable events shook County areas with a (maximum) magnitude 7.4 shock in the early morning of June 28, 1992. These quakes originated along related segments of the San Andreas Fault approximately 90 miles to the north. I Locally high levels of ground shaking over an extended period of time resulted; however, significant damages to local structures were not reported. The increase in earthquake frequency in the region remains a subject of speculation among l geologists; however, based upon empirical information and the recorded seismic history of county areas, the 1986 and 1992 events are thought to represent the highest levels of ground shaking which can be expected at the study site as a I result of seismic activity. In recent years, the Rose Canyon Fault has received added attention from I geologists. The fault is a significant structural feature in metropolitan San Diego which includes a series of parallel breaks trending southward from La Jolla Cove through San Diego Bay toward the Mexican border. Recent trenching along the I fault in Rose Canyon indicated that at that location the fault was last active 6,000 to 9,000 years ago. Thus, the fault is classified as "active" by the State of California which defines faults that evidence displacement in the previous 11,000 1 years. as active. I .More active faults (listed on the preceding page) are considered most likely to impact the region during the lifetime of the project. The faults are periodically active and capable of generating moderate to locally high levels of ground I .shaking site. Ground separation as a result of seismic activity is not expected at the property. I D. Geologic Structure/Slope Stability Large-scale landslide terrain are known to impact hillside terrain in the vicinity of I the project site. The slides are related to weak earth materials or unsupported geologic structure in an inclined condition. I I VINJE & MIDDLETON ENGINEERING, INC. o 2450 Auto Park Way Escondido, California 92029-1229 0 Phone (760) 743-1214 PRELIMINARY SOIL AND GEOTECHNICAL INVESTIGATION PAGE 5 PARCELS A,B,C, ADAMS STREET, CARLSBAD AUGUST 10, 1998 At the project site, test trench exposures indicate general flat-lying conditions within underlying earth deposits. The indicated relationship of site materials is depicted on aGeologic Cross-Section enclosed with this report as Plate 7. Landslides or other forms of existing slope instability are not indicated within project terrain. However, loose terrace deposit sands are indicated at the site (see Test Trench T-7) which may create temporary slope stability problems during site development. Geologic Hazards I Geologic hazards are not presently indicated at the project site. Project terrain does not indicate gross geologic instability. The most significant geologic hazards at the property will be those associated with ground shaking in the event of a major seismic occurrence. Liquefaction or related ground rupture failures are not anticipated. Laboratory Testing/Results I Earth deposits encountered in our test borings were closely examined and sampled for laboratory testing to determine their ability to support the planned structures and improvements. Based upon out test data and field exposures, site I soils have been grouped into the following soil types: TABLE 2 I : Desriptin: : I grey-brown sandy clay (coil uvium/topsoil) I Soiljy: 2 brown fine sand (terrace deposit) 3 off-white silty sand (sandstone formational rock) 4 light brown to tan medium to coarse clean sand (Terrace deposit) The following tests were conducted in support of this investigation: I. Maximum Dry Density and Optimum Moisture Content: The maximum dry density and optimum moisture content of Soil Types I and 2 were determined in accordance with ASTM D-1 557-91. The results are presented in Table 3. VINJE & MIDDLETON ENGINEERING, INC. 0 2450 Auto Park Way ° Escondido California 92029-1229 Phone (760) 743-1214 I I I I I I I I PRELIMINARY SOIL AND GEOTECHNICAL INVESTIGATION PAGE 6 PARCELS AB,C, ADAMS STREET, CARLSBAD AUGUST 10, 1998 TABLE 3 C Soil Miñiu14ry Op4ñim Moisjre Gcnteit 1-1 @ 3' 1 122.9 12.4 T-2@5' 2 127.1 10.3 I 2. Moisture-Density Tests (Undisturbed Chunk Samples): In-place dry density and moisture contents of representative soil deposits beneath the site were determined from relatively undisturbed chunk samples using the I water displacement method. Results are presented in Table 4 and tabulated on the attached Test Boring Logs. TABLE 4 S.imple. Location Soil :Type NO gt rloi.,ture Cont w'uJ - Field Dry Density '(Yd-pcf) Max Dr Dens (ni-pcf) Ratio Of In-Place Dry Densit-j To Max Dr Dnity .(.YdL ni 1001 T-1 @3' I 1 I - 12.2 I - 122.9 sampledisturbed 1-1 ©_7' 2 3.7 - 127.1 sampledisturbed T-2 c 5' 2 8.1 111.3 127.1 87.6 T-3@7' 3 9.4 125.1 - - 1-4 @_3' 3 7.9 129.7 - - T-5)7' 2 87 IlOR 1771 870 *Designated as relative compaction for structural fills. Required relative compaction for structural fill is 90% or greater. 3. DirectShearTest: Two direct shear tests were performed on representative samples of Soil Type 1 and 2. The prepared specimens were soaked overnight, loaded with normal loads of 1, 2, and 4 kips per square foot respectively, and sheared to failure in an undrained condition. The test results are presented in Table 5. TABLE 5 • • • Wir. Añqle f • Apparent Swpl Soil Sample Dens illy int. Fri.. cohesion Location Type ea 1-1c3 1 remolded 123.4 27 807 T-2@5' 2 remolded 125.7 34 232 VINJE & MIDDLETON ENGINEERING, INC. ° 2450 Auto Park Way Escondido, California 92029-1229 Phone (760) 743-1214 PRELIMINARY SOIL AND GEOTECHNICAL INVESTIGATION PAGE 7 PARCELS A,B,C, ADAMS STREET, CARLSBAD AUGUST 10, 1998 4. Expansion Index Test: Two expansion index tests were performed on representative samples of Soil Type I and 2 in accordance with the Uniform Building Code Standard 18-2. The test results are presented in Table 6. TABLE 6 Sample Soil Rmolded o Saturatiin S turated Expansion All Epauston Loia&ion.. Type . (i). - . (.) .. . .. .:.Jñdex tEl) . Potii.tiài* T-1 @ 3' 1 11.8 50.6 23.4 51 medium T-2 @ 5' 2 8.6 50.7 21.8 0 very low (co) = moisture content in percent VI. CONCLUSIONS Based upon the foregoing site investigation, development of Parcels A, B, and C, at the study site is feasible from a geotechnical viewpoint. Existing slope conditions are stable and earth materials at the project site are predominantly non-expansive sandy deposits which will work well in compacted fills. Unusual excavation difficulty is not.expected. The following geotechnical conditions are unique to the site and are expected to impact project development: * The study presented in this report only investigated general site feasibility for the proposed development. Site specific reports will be required, particularly for Parcels A and C when grading scheme for project sites are known. * For the most part, temporary construction slopes at the project site are expected to expose competent earth materials which can be graded at 1:1 gradients. A known exception to this will occur in the upper reaches of Parcel C where loose, unstable sands will emerge. Recommendations for temporary cut slopes in loose terrace deposit sands at the project site are presented in a following section. * Retaining walls are planned at the site to generate yard and building areas for each parcel. Adequate back-drainage for the walls is a critical element in this proper performance. Added care should be taken to suitably waterproof and drain project retaining walls. Surface areas of the site should be prepared for building by conventional removal and recompaction of existing upper loose and unsuitable soils, as recommended below. VINJE & MIDDLETON ENGINEERING, INC. 2450 Auto Park Way ° Escondido, California 92029-1229 Phone (760) 743-1214 I PRELIMINARY SOIL AND GEOTECHNICAL INVESTIGATION PAGE 8 PARCELS A,B,C, ADAMS STREET, CARLSBAD AUGUST 10, 1998 * Groundwater conditions were not encountered during our investigation and are not expected to be a problem in development of the site as planned. - * Potentially expansive clayey soils were indicated at the site and are expected to be in minor quantities (upper colluvium/topsoils). Attempts should be made to bury expansive soils in deeper fills below the upper three from the rough finish grade using the select grading techniques. I * Maximum post construction settlement is not expected to exceed approximately 1-inch, and should occur below the heaviest loaded footings provided our I recommendations for remedial grading and site development are followed. The magnitude of post construction differential settlements (as expressed in terms of angular distortion) is not anticipated to exceed 1%-inch between similar elements, I in a 30-foot span. * Liquefaction and seismically induced settlements and will not impact the proposed I .development and structures provided our recommendations for remedial grading and site development are followed. I * Soil collapse will not be a factor in development of the study site provided our recommendations for site development are followed. I VII. RECOMMENDATIONS The following recommendations are consistent with the project geotechnical conditions. I Recommendations given below should be incorporated in to final plans and implemented during the construction phase. I A. Grading and Earthworks I Conventional grading techniques may be used in order to achieve final design grades and improve soil conditions beneath the structures and improvements. All grading and earthworks should be completed in accordance with Appendix I Chapter 33 of the Uniform Building Code, City of Carlsbad grading ordinances and the requirements of the following section wherever applicable. I l. Clearing and Grubbing: Surface vegetation and other deleterious materials should be removed from areas to receive fills, structures and improvements. Removals should he inspected and approved by the project I geotechnical engineer or his designated field representative prior to grading. n VINTE & MIDDLETON ENGINEERING, INC. 2450 Auto Park Way I Escondido, California 92029-1229 0 Phone (760) 743-1214 I PRELIMINARY SOIL AND GEOTECHNICAL INVESTIGATION PAGE 9 PARCELS A5B,C, ADAMS STREET, CARLSBAD AUGUST 10, 1998 2. Removals and Over-Excavation: The most effective soil improvement method to mitigate loose upper soils will utilize removal and recompaction using conventional grading techniques. Site upper soils should be removed to underlying bedrock as approved by the project soils engineer and placed back as properly compacted fill. Approximate removal depths in the vicinity of individual exploratory excavation sites are shown on Table 7. Locally deeper removals may be necessary based on the actual field exposures and should be anticipated. TABLE 7 Trench Total Trench . al -.. Estiniated Depth Estimated RemovMIN Location Depth tci Water..ft) Depth ft) Comments T-1 8' I We • 6W I T-2 9' We T-3 7' We 5W T-4 4' We 1' depth of undercut may govern T-5 8' We 4' T-6 7' We 2' depth of undercut may govern T-7 10' We 9' local caving from 2' T-8 1L__ 9' I We 2' r I depth of undercut may govern Notes: All depths are measured from the existing ground levels. Actual depths may vary at the time of construction based on seasonal conditions and actual subsurface exposures. Bottom of all over-excavations should be ripped and recompacted in-place as directed in the field. Firm native ground is defined as natural deposits with greater than 90% compaction levels. n/e: not encountered. Tensar Bx-1100 may be required to stabilize bottom of over-excavations prior to fill placement as determined in the field. Select Grading: Minor to modest amounts of expansive soils are present at the site. Attempts should be made to bury the potentially expansive soils in deeper fills and placing non-expansive sandy soils available from the excavation of on-site sandstone/terrace deposits within the upper three of the pad grade using select grading techniques. There should be a minimum of 1-foot of non-expansive compacted soils below the deepest footing. Temporary Construction Slopes: Loose unstable sands were encountered in the upper reaches of Parcel C which will create excavation VINJE & MIDDLETON ENGINEERING, Ii.ic. 2450 Auto Park Way o Escondido, California 92029-1229 Phone (760) 743-1214 I I I I PRELIMINARY SOIL AND GEOTECHNICAL INVESTIGATION PAGE 10 PARCELS A,B,C, ADAMS STREET, CARLSBAD AUGUST 10, 1998 difficulties during removal and construction operations. Grading scheme and project architectural plans were not available to us at the time of preparation of this report. Mitigation will depend on design grades/architect plan and may include temporary shoring, soil treatment using grading options and in- situ soil improvement techniques. Appropriate recommendations should be given by the project soil engineer at the time of grading and foundation plan review when details of construction are known. Elsewhere temporary construction slopes required during removal operations should not exceed 1:1 gradients maximum. Minor sloughing the temporary slopes may occur and should be anticipated. S. Fill Materials/Compaction: Removed soils are suitable for reuse as compacted site fill. Fill soils should be moisture conditioned to near optimum levels and mechanically compacted in thin, horizontal lifts to at least 90% of the corresponding laboratory maximum density value per ASTM D-1557-91 unless otherwise specified. 6. Graded Slopes: Graded cut and fill slopes at the project site should be programmed for 2:1 gradients maximum. Cut and fill slopes constructed at 2:1 gradients will be grossly stable with respect to deep seated and surficial failures for the maximum anticipated design heights. Grade fill slopes should be compacted to minimum 90% out to the slope face. Overbuilding and culling back to the compacted core or backrolling at minimum 4 feet vertical increments and "track-walking" the slope face is recommended. Graded cut slopes exposing loose sandy and erodible deposits should be reconstructed as a stabilization fill slopes. For this purpose an equipment wide keyway should be established at the toe of the slope. The keyway should be at least 2 feet deep below rough pad grade and heeled back a minimum of 2% into the natural hillside. Actual keyway dimensions should be determined in the field based upon actual exposures. Additional recommendations should be given at the time of grading plan review when the project grading scheme is known. Reconstructed slope should maintain finish gradients no steeper than 2:1 (horizontal to vertical) and compacted to minimum 90% out to the slope face. VJNJE & MIDDLETON ENGINEERING, INC. 2450 Auto Park Way o Escondido, California 92029-1229 0 Phone (760) 743-1214 I Al I I I PRELIMINARY SOIL AND GEOTECHNICAL INVESTIGATION PAGE 11 I ci PARCELS A,B,C, ADAMS STREET, CARLSBAD AUGUST 10, 1998 ca kb 4, inspections: Site grading operations should be tested and inspected by the project geotechnical engineer or his designated field representative on a continuous basis. Particular attention should be given to over-excavations and removals, and fill compaction. Geotechnical engineering observations and testing should be presented in a formal as-graded compaction report at the completion of rough grading. Surface Drainage/Erosion Control: A critical element to the continued stability of the graded building pads and slopes is adequate surface drainage system, and protection of the slope face. This can most effectively be achieved by appropriate vegetation cover and the installation of the. following systems: Drainage swales should be provided at the top and toe of the slopes per ( project civil engineer design. * Building pad and slope: surface run-off should be collected and directed to a selected location in a controlled manner. * The finish slope should be planted soon after completion of grading. Unprotected slope faces will be subject to severe erosion and should not be 53 allowed. Over watering of the slope faces should also not be allowed. Only the amount of water to sustain vegetation life should be provided. ~cL s B. 'Foundations and Slab-On-Grade Floors ku The following recommendations are consistent with very low expansive foundation. bearing soils (El(21) anticipated at the study site. Final foundation and slab design will depend on expansion characteristics of finish grade soils and differential fill thickness. All foundations and slab recommendations should be confirmed and/or revised as necessary in the site final as-graded compaction report. Revised recommendations may be necessary and should be anticipated. I 1. The proposed building may be supported on stiff shallow foundations. The shallow foundations should be founded on certified bearing soils. Acceptable foundations should include a system of concrete spread pad and strip footings and slab-on-grade floors. 2. Continuous strip foundations should be sized at least 12 inches wide by 12 I inches deep for single-story structures and 15 inches wide by 18 inches deep for two-story structures. Spread pad footings should be at least 24 I I VINJE & MJDDLETON ENGINEERING, INC. 0 2450 Auto Park Way Escondido, California 92029-1229 6 Phone (760) 743-1214 -I -) I PRELIMINARY SOIL AND GEOTECHNICAL INVESTIGATION PAGE 12 PARCELS A,B,C, ADAMS STREET, CARLSBAD AUGUST 10, 1998 inches square and 12 inches deep. All depths are measured from the lowest finish rough grades not including the recommended sand underlay beneath I the slabs. Exterior continuous strip footings should enclose the entire building perimeter. 3. Continuous strip foundations should be reinforced with a minimum of 444 reinforcing bars. Place 244 bars 3 inches above the bottom of the footing I and 244 bars 3 inches below the top of the footing. Reinforcement for the spread pad footings should be designed by the project structural engineer. 1 4. All interior slabs should be a minimum of 4 inches in thickness and reinforced with #3 bars spaced 18 inches on center each way placed mid- height in the slab. Slabs should be underlain with 4 inches of clean sand (SE 30 or greater). Place a six-mil plastic moisture barrier mid-height in the I clean sand. Subgrade soils should be tested for proper moisture and specified compaction levels and approved by the project geotechnical consultant I within 72 hours prior to the placement of concrete. Provide contraction joints consisting of sawcuts spaced 10 feet on center I each way within 24 hours of concrete pour for all interior slabs. The sawcuts should be a minimum of -3/4-inch in depth but should not exceed 11/2-inches I in depth or the reinforcing may be damaged. Provide re-entrant corner reinforcement for all interior slabs. Re-entrant corners will depend on slab geometry and/or interior column locations. The enclosed Plate 8 may be used as a general guideline. C. Exterior Concrete Slabs/Flat works 1. All exterior slabs (walkways, and patios) should be a minimum of 4 inches P in thickness reinforced with 6x6/10x10 welded wire mesh placed at mid- height of the slab. I 2. PCC driveways and parking should be a minimum of 5 inches in thickness and reinforced with #3 reinforcing bars spaced 18 inches on center each way, placed at mid-height of the slab. Subgrade soils beneath the PCC I driveways and parking should be compacted to a minimum of 95% of the corresponding maximum dry density within the upper 6 inches. In the case I VINJE & MIDDLETON ENGrNEERING, INC. 0 2450 Auto Park Way I Escondido, California 92029-1229 Phone (760) 743-1214 PRELIMINARY-SOIL AND GEOTECHNICAL INVESTIGATION PAGE 13 PARCELS A,B,C, ADAMS STREET, CARLSBAD AUGUST 10, 1998 of potentially expansive soils (El)20), provide a minimum of 6 inches of 95% compacted Caltrans Class II base under PCC driveways and parking. Provide weakened joints consisting of sawcuts spaced 10 feet on center (not to exceed. 12 feet maximum) each way within 24 hours of concrete pour. The sawcuts should be a minimum depth of 3/4-inch but should not exceed I 1/ inches deep. All exterior slab designs should be confirmed in the final as-graded compaction report. Sub and base grade soils should be tested for proper moisture and specified compaction levels and approved by the project geotechnical consultant within 72 hours prior to the placement of concrete. D. Soil Design Parameters The following soil design parameters are based on the tested representative samples of on-site earth deposits. All parameters should be re-evaluated when the characteristics of the final as-graded soils have, been specifically determined. Revised recommendations may be necessary and should be anticipated. I 1 . Design wet density of soil = 125.7 pcf. Design angle of internal friction of soil = 34 degrees. Design active soil pressure for retaining structures = 36 pcf (EFP), level backfill, cantilever, unrestrained walls. Design active soil pressure for retaining structures= 54 pcf (EFP), 2:1 backfill surface, cantilever, unrestrained walls. Design at-rest soil pressure for retaining structures = 55 pcf (EFP), non-yielding, restrained walls. Design passive soil pressure for retaining structures = 444 pcf (EFP), level surface at the toe. Design coefficient of friction for concrete on soils = 0.40. Allowable foundation pressure for certified compacted on-site soil= 1900 psf. Allowable lateral bearing pressure (all structures except retaining walls) for certified on-site soils = 150 psf/ft. I I I I Notes: * Because large movements must take place before maximum passive resistance can be developed, a minimum safety factor of two should be considered for VINJE & MIDDLETON ENGINEERING, INC. 0 2450 Auto Park Way 0 Escondido, California 92029-1229 1 Phone (760) 743-1214 I PRELIMINARY SOIL AND GEOTECKNICAL INVESTIGATION PAGE 14 PARCELS A,B,C, ADAMS STREET, CARLSBAD AUGUST 10, 19:8 I •. sliding stability where structures and improvements are planned near or on top of retaining walls. * When combining pressure and frictional resistance, the passive component should be reduced by one-third. * The allowable foundation pressure provided herein was determined for footings having a minimum width of 12 inches and a minimum depth of 12 inches. This value may be increased per Uniform Building Code for additional depths or widths and depths as permitted, (Table 18-I-A, Footnote 2). I . * The allowable foundation pressures provided herein applies to dead plus Jive loads and may be increased by one-third for wind and seismic loading. * The lateral bearing earth pressures may be increased by the amount of the designated value for each additional foot of depth to a maximum of 1,500 pounds per square foot. - * Any additional surcharge loads due to adjacent buildings and structures should I be considered by the project structural engineer. E. Asphalt Pavement Design Specific pavement designs can best be provided at the completion of rough grading based on R-Value tests of the actual imported finish subgrade soils; however, the following, structural sections may be considered for cost estimating purposes only (not for construction). I.. 1. A minimum section of 3 inches asphalt on 6 inches of Caltrans Class II base may be anticipated. Base materials should be compacted to a minimum of 95% I . of the maximum dry density. 2. Subgrade soils beneath the asphalt roadway, parking and driveways should be compacted to a minimum of 95% of the corresponding maximum dry density I within the upper 1-foot. Sub and base grade soils should be tested for proper moisture and minimum 95% compaction levels and approved by the project geotechnical consultant within 72 hours prior to the placement of the base or I asphalt layers. I I I VINJE & MIDDLETON ENGINEERING, INc. 2450 Auto Park Way ° Escondido, California 92029-1229 1 Phone (760) 743-1214 PRELIMINARY SOIL AND GEOTECHNICAL INVESTIGATION PAGE 1 PARCELS A,B,C, ADAMS STREET, CARLSBAD AUGUST 10, 1998 F. General Recommendations The minimum foundation design and steel reinforcement provided herein is based On soil characteristics only and is not intended to be in lieu of reinforcement necessary for structural considerations. All recommendations should be evaluated and confirmed by the project architect/structural engineer. Footings located on or adjacent to the top of slopes should be extended to a sufficient depth to provide a minimum horizontal distance of 7 feet or one-third of the slope height, whichever is greater (need not exceed 40 feet maximum) between the bottom edge of the footing and face of slope. This requirements applies to all improvements and structures including fences, posts, pools, spas, etc. Concrete and AC improvements should be provided with a thicken edge to satisfy this requirement. Expansive clayey soils should not be used for backfilling of any retaining structure. All retaining walls should be provided with a 1:1 wedge of granular, compacted backfill measured from the base of the wall footing to the finished surface. Retaining walls should be provided with a back drainage in general accordance with the attached Plate 9. All underground utility trenches should be compacted to a minimum of 90% of the maximum dry density of the soil unless otherwise specified by the respective agencies. Care should be taken not to crush the utilities or pipes during the compaction of the soil. Non-expansive, granular backfill soils should be used. Site drainage over the finished pad surface should flow away from structures onto the street in a positive manner. Care should be taken during the construction, improvement, and fine grading phases not to disrupt the designed drainage patterns. Rooflines of the buildings should be provided with roof gutters. Roof water should be collected and directed away from the building and structures to a suitable location. Considerations should be given by the project architect to adequately damp proofing/water proofing the basement walls/foundations and provide the planter areas adjacent to the foundations with an impermeable liner and a subdrainage system. Finish surfaces for all improvements and hard scape including placement of asphalt and concrete, should be completed within 72 hours after the approval of base/subgrade by the project soils engineer. Additional inspection, testing and certification of the base/subgrade receiving finish surfaces will be necessary in the event the specified time period is not met. \/INJE & MIDDLETON ENGINEERING, INC. 2450 Auto Park Way 0 Escondido, California 92029-1229 Phone (760) 743-1214 I PRELIMINARY SOIL AND GEOTECHNICAL INVESTIGATION PAGE 15 I PARCELS A,B,C, ADAMS STREET, CARLSBAD AUGUST 10, 1998 I 7. Final grading and foundation plans should reflect preliminary recommendations given in this report and should be reviewed by this office prior to grading. More ' specific recommendations should be provided when final drawings are available. I 8. All foundation trenches should be inspected to assure adequate footing embedment and confirm competent bearing soils. Foundation and slab reinforcements should also be inspected and approved by the project I geotechnical consultant. The amount of shrinkage and related cracks that occurs in the concrete slab-on- grades, flatworks and driveways depends on many factors, the most important of which is the amount of water in a concrete mix. The purpose of the slab reinforcement is to keep normal concrete shrinkage cracks closed tightly. The amount of concrete shrinkage can be minimized by reducing the amount of water in the mix. To keep shrinkage to a minimum, the following should be considered: * Use the stiffest mix that can be handled and consolidated satisfactorily. * Use the largest maximum size of aggregate that is practical, (for example, concrete made with three-eights inch maximum size aggregate usually requires about 40 lbs more (nearly 5 gal.) water per cubic yard than concrete with one inch aggregate). * Cure the concrete as long as practical. The amount of slab reinforcement provided for conventional slab-on-grade construction considers that good quality concrete materials, proportioning, craftsmanship, and control tests where appropriate and applicable are provided. A preconstruction meeting between representatives of this office and the property owner or planner, as well as the grading contractor/builder, is recommended in order to discuss grading/construction details associated with site development. VINJE & MIDDLETON ENGINEERING, INC. 0 2450 Auto Park Way Escondido, California 920294229 0 Phone (760) 743-1214 PRELIMINARY SOIL AND GEOTECHNICAL INVESTIGATION PAGE 17 PARCELS A,B,C, ADAMS STREET, CARLSBAD AUGUST 10, 1998 VIII. LIMITATIONS The conclusions and recommendations provided herein have been based on available data obtained from pertinent reports and plans, subsurface exploratory excavations as well as our experience with the soils and formational materials located in the general area. The materials encountered on the project site and utilized in our laboratory testing are believed representative of the total area; however, earth materials may vary in characteristics between excavations. Of necessity we must assume a certain degree of continuity between exploratory excavations and/or natural exposures. It is necessary, therefore, that all observations, conclusions, and recommendations be verified during the grading operation. In the event discrepancies are noted, we should be contacted immediately so that an inspection can be made and additional recommendations issued if required. The recommendations made in this report are applicable to the site at the time this report was prepared. It is the responsibility of the owner/developer to insure that these recommendations are carried out in the field. It is almost impossible to predict with certainty the future performance of a property. The future behavior of the site is also dependent on numerous unpredictable variables, such as earthquakes, rainfall, and on-site drainage patterns. R The firm of VINJE & MIDDLETON ENGINEERING, INC. shall not be held responsible for changes to the physical conditions of the property such as addition of fill soils, added cut slopes, or changing drainage patterns which occur without our inspection or control. The property owner(s) should be aware that the development of cracks in all concrete I surfaces such as floor slabs and exterior stucco are associated with normal concrete shrinkage during the curing process. These features depend chiefly upon the condition of concrete and weather conditions at the time of construction and do not reflect I detrimental ground movement. Hairline stucco cracks will often develop at window/door corners, and floor surface cracks up to 1/s-inch wide in 20 feet may develop as a result of I normal concrete shrinkage (according to the American Concrete Institute). This report should be considered valid for a period of one year and is subject to review by our firm following that time. If significant modifications are made to your tentative I development plan, especially with respect to the height and location of cut and fill slopes, this report must be presented to us for review and possible revision. H I -- VTNJE & MIDDLETON ENGINEERING, INC. 0 2450 Auto Park Way 0 Escondido, California 92029-1229 0 Phone (760) 743-1214 GE #863 I I I I I I I I I I I I I I I I PRELIMINARY SOIL AND GEOTECHNIGAL INVESTIGATION PAGE 18 PARCELS A,B,C, ADAMS STREET, CARLSBAD AUGUST 10, 1998 Vinje & Middleton Engineering, Inc. warrants that this report has been prepared within the limits prescribed by our client with the usual thoroughness and competence of the engineering profession. No other warranty or representation, either expressed or implied, is included or intended. We appreciate this opportunity to be of service to you. VINJE & MIDDLETON ENGINEERJ/IG, INC. Dennis Middleton CEG #980 'çED GoN (' CEG980 z\ * I CERTIFIED 'A \ ENGINEERING / Mehdi ShariE RCE #46174 Distribution: Addressee 5 RMV/DM/MS/jt sms\wpd0cs'.98-257-p.pgi Al ks, No. 46174 .1 EXR 12-31.98J (10 OFES Cr_ SIOA7 LU r E. 12•31O1 LP 1 VINIE & MIDDLETON ENGINEERING INC. 0 2450 Auto Park Way 0 Escondido, California 92029-1229 Phone (760) 743-1214 • • • / I / 1 • .••• L • / I • I•-• - - \ • wT_ \ • , P • I .1 / 1/ \ \ \ \,\3 \ CD \\• art \\\ \ \ \ \ P I R • • •• • "Mr IMIt xw3 'j II 1/I • •: • *1 •\ \\• •• :/i II ./ // " •Il LLJ 110 LO V6. I T LLJ go ~A ••••. • • G EOTEC H NI CAL MAP Locotion of test trench • Scale: 1" 30' Adams Street,, Parcels af ROAD FILL DEPOSIT < N] Carlsbad Calif. Qt TERRACE DEPOSIT PLATE I Ts FORMATIOAL ROCK Date: 7-1-98 Logged by: DM DEPTH SAMPLE 7 MOISTURE DRY DENSITY RELATIVE COMPACTION DESCRIPTION (¼) (pcf) (¼) -0- Silty sand. Brown. Dry, loose - - B COLLUVIUM: - - Sandy clay. Mottled grey-brown. White carbonate spots in upper - 5 - 3'. Slightly moist, hard. ST-1 From 4, grades more sandy 12 2 3-7 - - TERRACE DEPOSIT: - 10 - Sandstone pale brown color. Fine grained, massive. Moderately - - well cemented to friable. Gradational contact. ST-2 - - End Trench at 8'. -15- Date: 7-1-98 Logged by: DM DEPTH SAMPLE 7 ' MOISTURE DRY DENSITY RELATIVE COMPACTION (ft) (%) (pcf) (¼) DESCRIPTION - 0 - TOPSOIL: - - Silty fine sand grading to sandy clay. Brown. Loose to stiff. ST-1 8 - 5 - U W TERRACE DEPOSIT: - - Sandstone. Tan to light brown. Fine to medium grained. 07. 1' - - Moderately well to weakly cemented. ST-2 At 4', attitude on 1" thick grey siltstone bed: No/I 5W. -10- - - From 6'- 8', sand is coarse grained, loose. End Trench at 9'. - - VINJE & MIDDLETON ENGINEERING, INC TESTTREN1H LOGS 2450 Vineyard Avenue, Suite 102 Escondido, California 92029i229 ADAMS STREET, CARLSBAD PROJECT NO. 98-257-P PLATE 2 Office 760-743-1214 Fax 760739-0343 Y Sand Cone Test M Bulk Sample U Chunk Sample 0 Driven Rings Date: 7-1-98 Logged by: D DRY RELATIVE SAMPLE I MOISTURE DENSITY COMPACTION (ft (%) (pcf) (%) DESCRIPTION - 0- TOPSOIL: - - Silty sand grading to sandy clay. Brown. Dry to moist, loose to - - hard. White carbonate stringers. - - TERRACE DEPOSIT: - 5 - Sandstone. Brown. Fine to medium grained. White carbonate spots. Massive. Weakly cemented. ST-2 - FORMATIONAL ROCK: - - Sandstone. Off-white color. Fine to coarse grained. Massive. -10 - Weakly cemented (erodable). ST-3 End Trench at 7'. - - -15- Date: 7-1-98 Logged by: DM T A DRY RELATIVE DEPTH SAMPLE '•' MOISTURE DENSITY COMPACTION (ft) (%) (pcf) (%) DESCRIPTION - 0 - FORMATIONAL ROCK: - - Sandstone. Off-white color. Fine to coarse grained. Horizontally - - stratified along discontinuous pebble beds. Moderately well - - cemented to friable. ST-3 7, - 5 - End Trench at 4'. -10- wL -15- VINJE & MIDDLETON ENGINEERING, INC TEST TRENCH LOGS 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 ADAMS STREET, CARLSBAD PROJECT NO. 98-257-P PLATE 3 Office 760-743-1214 Fax 760-739-0343 V Sand Cone Test IM Bulk Sample U Chunk Sample 0 Driven Rings I I I I Date: 7-1-98 Logged by: DM 04 DEPTH SAMPLE T-5 ' MOISTURE DRY DENSITY RELATIVE COMPACTION DESCRIPTION (%) (pcf) (%) -0-. - - Silty sand. Brown. Dry, loose. - - COLLUVIUM: Sandy clay. Mottled brown. White carbonate spots 2'- 3. Moist, - 5 - hard. ST-1 TERRACE DEPOSIT: - Sa ~a'ssive. dstone. Pale brown color. Mottled. Fine to medium grained. 2. 1, o - - Cemented friable. ST-2 -10- - - End Trench at 8'. -15- Date: 7-1-98 Logged by: DM DEPTH (It) SAMPLE -r I MOISTURE (%) DRY DENSITY (pcI) RELATIVE COMPACTION 1%) DESCRIPTION - 0 - TOPSOIL/FILL: Silty fine sand. Brown. Dry, loose. - - TERRACE DEPOSIT: - 5 - Sandstone. Pale brown color. Fine grained. Cemented friable. - - Locally coarse grained. ST-2 From 6', color grades to grey-brown. Mottled. Well cemented. - - - - ST-2 -10- - - End Trench at 7'. -15- VINJE & MDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 Office 760743-1214 Fax 7607390343 V Sand Cone Test 11 Bulk Samte ADAMS STREET, CARLSBAD PROJECT NO, 98257-P PLATE 4 0 Chunk Sample 0 Driven RinQs Date: 7-1-98 Logged by: DM DRY RELATIVE DEPTH SAMPLE MOISTURE DENSITY COMPACTION (%) (pd) (%) DESCRIPTION - 0- : TERRACE DEPOSIT: - - - Sand. Light brown to tan color. Medium to coarse grained. - 5 - Clean. Moist, loose. Local caving from 2'. Horizontally stratified - - along coarse sand seams. ST-4 -10 - End Trench at 10'. -15- Date: 7-1-98 Logged by: DM DEPTH (ft) SAMPLE - -o MOISTURE (%) RELATIVE DRY DENSITY (pcf) COMPACTION (%) DESCRIPTION - 0 - - - - - -5- TERRACE DEPOSIT: Sandstone. Brown color. Fine to medium grained. Massive. Cemented friable. ST-2 'I FORMATIONAL ROCK: Sandstone. Off-white color. Medium grained. Cemented friable. Upper contact gradational. ST-3 -10 - - - End Trench at 9'. VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 Office 760-743-1214 Fax 760-73-0343 TESTTRE1CHLOS ADAMS ASTREET,AD PROJECT NO. 98-257-P PLATE 5 V Sand Cone Test 13 Bulk Sample L1 Chunk Sample 0 Driven Rings I rS... I "? I I a0 SonOiego Io I 30 20 10 0 30 MILES - FAULT - EPICENTER MAP I SAN DIEGO COUNTY REGION INDICATED EARTHQUAKE EVENTS THROUGH 75 YEAR PERIOD (1900-1974) Map data is compiled from various sources including California Division of Mines and Geology, California Institude of. Technology and the National Oceanic and Atmospheric Administration. Map is reproduced from California Division of Mines and Geology, I "Earthquake Epicenter Map of California; Map Sheet 39." I Earthquake Magnitude ............... 0 ............5.0T05.9 ED ............6.0 TO 6.9 PROJECT: 98-257-P 70 TO 7.9 Adorns St. Carlsbad Fault. PLATE NO. 6 Wo 40 20 0 I 20 0 GEOLOGIC CRGLS =SEC1/ON PLATE 7 ScoIe: 1'3O' IULP I IUN JUIN I b AND t-PN I <AN I UU(NLK INIUI(LtMbN I Typical - no scale (a) (b) ISOLATION JOINTS 101 CONTRACTION JOINTS (c) RE-ENTRANT C( RE IFO RCEMEN NO. 4 BARS PL BELOW TOP OF ENTRANT NER CRACK NOTES: Isolation joints around the columns should be either circular as shown in (a) or diamond shaped as shown in (b). If no isolation joints are used around columns, or if the corners of the isolation joints do not meet the contraction joints, radial cracking as shown in (c)may occur (reference Ad). In order to control cracking at the re-entrant corners (±2700 corners), provide reinforcement as shown in (c). Re-entrant corner reinforcement shown herein is provided as a general guideline only and is subject to verification and changes by the project architect and/or structural engineer based upon slab geometry, location, and other engineering and construction factors. VNJE & MDDLETON ENGI NEERING, INC. PLATE 8 RETAINING WALL DRAIN DETAIL Typical no scale Waterproofing Perforated drain pipe drainage : '•'./' Granular, non-expansive ' Cifill. Compacted. , / __ Filter Material. Crushed rock (wrapped in filter fabric) or Class 2 Permeable Material / (see specifications below) - /Av/-- I" Competent, approved soils or bedrock CONSTRUCTION SPECIFICATIONS: - Provide granular, non-expansive backfill soil in 1:1 gradient wedge behind wall. Compact backfill to minimum 90% of laboratory standard. Provide back drainage for wall to prevent build-up of hydrostatic pressures. Use drainage openings along base of wall or back drain system as outlined below. Backdrain should consist of 4" diameter PVC pipe (Schedule 40 or equivalent) with perforations down. Drain to suitable outlet at minimum 1%. Provide 3,4" - 11/2fl crushed gravel filter wrapped in filter fabric (Mirafi 140N or equivalent). Delete filter fabric wrap if Caftrans Class 2 permeable material is used. Compact Class 2 material to minimum 90% of laboratory standard. Seal back of wall with waterproofing in accordance with architect's specifications. Provide positive drainage to disallow ponding of water above wall. Lined drainage ditch to minimum 2% flow away from wall is recommended. * Use 11/2 cubic foot per foot with granular backfill soil and 4 cubic foot per foot if expansive backfill soil is used. VINJE & MIDDLETON ENGINEERING, INC. PLATE# 9