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CT 12-05; LA COSTA RESIDENTIAL; Update and Addendum to Geotechnical Investigation La Costa Town Center Residential Development; 2012-11-16
GEOTECHNICAL UPDATE AND ADDENDUM TO GEOTECHNICAL INVESTIGATION PROPOSED LA COSTA TOWN CENTER RESIDENTIAL DEVELOPMENT, CARLSBAD, CALIFORNIA Prepared for: TAYLOR MORRISON OF CA, LLC 8105 Irvine Center Drive, Suite 1450 Irvine, California 92618 Project No. 042631-001 November 16, 2012 ----Leighton and Associates , Inc . ___ .. A LEI GHTON GRO UP COMPANY c-, f 1 -u s - t 0 z ~ c., w :c 0 z < ...J ti. I Leighton and Associates 1 Inc. A LEIGHTON GROUP COMPANY November 16, 2012 Project No. 042631-001 Taylor Morrison of CA, LLC 8105 Irvine Center Drive, Suite 1450 Irvine, California 92618 Attention: Subject: Ms. April Tornillo Geotechnical Update and Addendum to Geotechnical Investigation Proposed La Costa Town Center Residential Development Carlsbad, California References: Leighton and Associates, Inc. 2012, Geotechnical Investigation, Proposed La Costa Town Center Residential Development, Carlsbad, California, Project No. 042631-001 , dated March 3, 2012 Latitude 33, 2012, Grading Plans. La Costa Town Center, Received October 2012 In accordance with your request and authorization, we have prepared this geotechnical update and addendum letter for the proposed La Costa Town Center, Carlsbad, California. As part of this update and addendum, we attended a project meeting on October 16, 2012, reviewed the above- referenced geotechnical report along with recent project grading plans. As requested by Taylor Morrison, the purpose of our update letter is revise geotechnical recommendations for building pad over-excavation from 4 feet to 3 feet, and to update our geotechnical map and geologic cross-section to new building pad elevations that have recently been raised. Based on our review of the current grading plans for the project prepared by Latitude 33, (Latitude 33, 2012), we understand the proposed development will include construction of thirty-two single- family residential buildings and associated improvements including roadways, building patios, driveways, parking areas, concrete flatwork, underground utilities, landscaping, etc. We also 3934 Murphy Canyon Road, Suite 8205 • San Diego, CA 92123-4425 858.292.8030 Fax 858.292.0771 www.leightongroup.com I 042631-001 understand that the proposed buildings will be two story structures and will likely be constructed with conventional or post-tension foundations. Based on the preliminary development plans, we anticipate the proposed finish grade elevations will be within a 1 to 5 feet of the existing mass- graded pad elevations. In addition, the proposed building pad grades on recent grading plans were raised approximately 1 foot. Addendum Recommendations In general, the geotechnical conditions of the site remain essentially as presented in the referenced geotechnical report, and it is our professional opinion that our previous geotechnical recommendations are still applicable and should be incorporated into the design, grading and construction of the proposed development, including addendum recommendations provided below. Note that we also recommend that the grading, retaining wall, and foundation plans be reviewed by Leighton prior to commencing construction. • Mitigation of CuUFill Transition Conditions and Building Pad Overexcavation In order to reduce the potential for differential settlement in areas of transition or cut-fill building pads and to remove metavolcanic rock in cut areas, we recommend that the entire cut portion of the building pad be overexcavated to a minimum depth of 3 feet below finished grade and replaced with properly compacted fill. This depth may be increased depending on adjacent fill depth as part of the recommended removals of artificial fill beneath the building pads. The overexcavation and recompaction should laterally extend at least 5 feet beyond limits of the building footprint. Based on our review of the updated grading plans, we have provided an approximate location of building pads overexcavations (Plate 1 ). Note that Leighton previously recommended 4 foot pad overexcavations was to mitigate risk of encountering difficult to non-rippable rock, minor grade variations during grading and to facilitate foundation and utility trench excavations. For deep utilities, we recommend the utility adjustments (streets, etc.) be over-excavated a minimum of 1 foot below the deepest utility. The recommendations provided in this update letter and our previous geotechnical report are based on preliminary design information and subsurface conditions provided during previous site As-graded reports. The interpolated subsurface conditions should be checked in the field during grading and/or construction. Construction observation of all onsite excavations and field density testing of all compacted fill should be performed by a representative of this office. -2-l . . r , 042631-001 If you have any questions regarding our update letter, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. William D. Olson, RCE 45283 Associate Engineer Mike D. Jensen, CEG 2457 Project Geologist Attachment: Figures -Geotechnical Map and Geologic Cross-section Appendix A -Geotechnical Report Distribution: (6) Addressee -3- •. ~-/t> '~.-··' . ~~, _ .. v ' , f'"""'--,f . ·.. ·1 ' ~... I [·"~·.· .. _,_./ ~cP . · ... \,,,_>,,,.'. ,/:.'_ ! c,~\"'.· .. ·.·.·.·' ... • '>i.,.~.'' ~ ",' .. -·\ '""( UCJ .··. ·••< ~' ·--·_-.,:--.. /K ", ·.-:: "> :. " :·-.." '\;, <::"-,) ~-;'.;:;.;c,:;·-,~". 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'\. ,F· .. •.,w .. 1 ... •,. ·.' •1 , · 1 , // . ·.·,. · ·· ·.-:,.o . ,.\, · .. \ Yf'-ky,• · \ . \ \ \ I ' . . . >"\.·.· ...•.. \\· .. o;.•••.·.'f,·x·.····•· ...... •<< ... ··\" \,,\. ''.oj~t.i.J\ \\ ... \\\ \\• \\ \ \/'\ / \' ' ..... ' .. <.[)·. ·. ·, ·--'· ·'~.i.--f,,;', '.. .. \ \ ' / -a-,·\· .... ,·. . ._ ''t\.·*'" \ .. , \ / '•• \t};·····\···''··\ ·\ \.f<(:\1.·\. \ \ \S> \' ·., '', . . .... ·· ...... · ·.\· .. -'·' ' -~ \ ... -,r.:_ i) ' \ t:!/ ' ·. . , .. ,._ \ ·. · .. c.\.-\ "" '\j/N. . . ' V o;; ·. ··~:>>.\<·· : .. \· .. :-. ,_:, .. \· __ -_\-~.Y ·-\ , -- A 380 ,,...... f-w w u... ........ z 340 0 i== <t > w ...J w 300 Existing Grade Af Af ············ ··--·· .. --..-----..;..,,----Afo ._,__ _ __ _ -=-----__ , ----·· ~··· ~··· ····---: .. ...... Jsp· Jsp Proposed Grade --Af Af ----- Approximate Limit of Proposed 0verexcavation due to metavolcanic rock Jsp Existing Grade Proposed Grade Jsp Jsp A' T Approximate Limit of Proposed 0verexcavation due to metavolcanic rock 340 300 260---l----...;...----'-------'----------'-----~------------------------'------'-------'----....... ----------'-----'------'-----'-------'------'-------------1--260 0 40 80 SCALE FEET LEGEND ---APPROXIMATE GEOLOGIC CONTACT Af Afo Jsp COMPACTED FILL FROM PREVIOUS GRADING (SCS&T, 2012) PRE-EXISTING FILL SANTIAGO PEAK VOLCANICS (CIRCLED WHERE BURIED) PLATE 2 Leighton CROSS-SECTION A-A" LA COSTA TOWN CENTER CARLSBAD, CALIFORNIA Proj: 042631-001 Eng/Geol: WDO/MOJ Scale: 1 "=40' Date: 11/2012 Drafted By; MAM Chf!,;~e,d By: P;\IJRAi'llNc.\~~1\DC1\0F_2012-11-1411.DWG (11-16-12 2:1B:41lPMJ Pli,ttad by. mmuri,hy GEOTECHNICAL UPDATE INVESTIGATION, PROPOSED LA COSTA TOWN CENTER RESIDENTIAL DEVELOPMENT CARLSBAD, CALIFORNIA Prepared For: TAYLOR MORRISON OF CA, LLC 8105 Irvine Center Drive, Suite 1450 Irvine, California 92618 Project No. 042631 -001 September 27, 2012 ----Leighton and Associates , Inc. ___ .. A LEI GHTON GROUP COMPANY Leighton and Associates, Inc. A LEI GHTON GROUP COMPANY September 27, 2012 Taylor Morrison of CA, LLC 8105 Irvine Center Drive, Suite 1450 Irvine, California 92618 Attention: Subject: Ms. April Tornillo Geotechnical Update Investigation Proposed La Costa Town Center Residential Development Carlsbad, California Project No. 042631-001 In accordance with your request and authorization, we have conducted a review of pertinent documentation (SCS&T, 2012) and have prepared this geotechnical update investigation for a proposed La Costa Town Center residential development to be built north of Rancho Santa Fe Road, south of Old Rancho Santa Fe Road, and west of Paseo Lupino in Carlsbad, California. Based on the results of our review, it is our professional opinion that the site is suitable for the proposed residential development provided that the recommendations presented herein are incorporated into the design, grading, and construction of the site. The accompanying report presents a summary of our investigation and provides preliminary geotechnical conclusions and recommendations relative to the proposed site development. Note that additional site exploration is recommended to further evaluate depth and characteristics of bedrock beneath the site. If you have any questions regarding our report, please do not hesitate to contact this office. We appreciate this opportunity to be of service. Respectfully submitted, Mike D. Jensen, CEG 245 Project Geologist Distribution: (3) Addressee William D. Olson, RCE 45283 Associate Engineer 3934 Murphy Canyon Road. Suite 8205 San Diego, CA 92123-4425 858.292.8030 Fax 858.292.0771 www.leightongroup.com 042631-001 TABLE OF CONTENTS Section 1.0 INTRODUCTION ...................................................................................................... 1 1.1 PURPOSE AND SCOPE .......................................................................................... 1 1.1.1 Scope of Work ............................................................................................... 1 1.2 SITE LOCATION AND DESCRIPTION ........................................................................ 2 1.3 PREVIOUS SITE DEVELOPMENT AND SITE GRADING ................................................ 2 1.4 PROPOSED DEVELOPMENT ................................................................................... 3 1.5 PREVIOUS lABORA TORY T ESTING ......................................................................... 4 2.0 SUMMARY OF GEOTECHNICAL CONDITIONS .................................................... 5 2.1 GEOLOGIC SETTING .................................•........................................................... 5 2.2 SITE-SPECIFIC GEOLOGY ..................................................................................... 5 2.2.1 Artificial Fill -Previously Existing (Afo) .......................................................... 5 2.2.2 Artificial Fill -Documented (Af) ..................................................................... 6 2.2.3 Santiago Peak Volcanics (Jsp) ...................................................................... 6 2.3 GEOLOGIC STRUCTURE ....................................................................................... 6 2.4 SURFACE AND GROUND WATER ........................................................................... 7 2.5 LANDSLIDES ........................................................................................................ 7 2.6 FLOOD HAZARD ................................................................................................... 7 2. 7 ENGINEERING CHARACTERISTICS OF THE ON-SITE SOILS ....................................... 7 2.7.1 Expansion Potential ....................................................................................... 7 2.7.2 Earthwork Shrinkage and Bulking ................................................................. 8 2.7.3 Excavation Characteristics ............................................................................ 8 2.7.4 Oversize Material .......................................................................................... 9 3.0 FAULTING AND SEISMICITY ................................................................................ 10 3.1 FAULTING ......................................................................................................... 10 3.2 SEISMICITY ······································································································· 10 3.2.1 Shallow Ground Rupture ............................................................................. 11 3.2.2 Liquefaction ................................................................................................. 11 3.2.3 Earthquake-Induced Settlement .................................................................. 11 3.2.4 Lateral Spread ............................................................................................. 11 3.2.5 Tsunamis and Seiches ................................................................................ 12 3.2.6 Building Code Seismic Parameters ............................................................. 12 4.0 CONCLUSIONS ..................................................................................................... 13 5.0 RECOMMENDATIONS .......................................................................................... 15 5.1 EARTHWORK ..... ··························· ...... ··········· .................................................... 15 5.1.1 Site Preparation ........................................................................................... 15 5.1.2 Excavations and Oversize Material ............................................................. 15 I I 042631--001 TABLE OF CONTENTS (Continued) Section 5.1 .3 Fill Placement.. ............................................................................................ 16 5.1.4 Cut/Fill Transition Mitigation and Pad Overexcavation ................................ 17 5.2 ROCK FILL SPECIFICATIONS ............................................................................... 18 5.3 TEMPORARY EXCAVATIONS ················································································ 18 5.4 SURFACE DRAINAGE AND EROSION ..................................................................... 19 5.5 FOUNDATION AND SLAB CONSIDERATIONS ........................................................... 19 5.5.1 Preliminary Foundation and Slab Design .................................................... 19 5.5.2 Settlement ................................................................................................... 22 5.5.3 Post-Tension Foundation Recommendations .............................................. 22 5.6 RETAINING WALL D ESIGN AND LATERAL EARTH P RESSURE .................................. 24 5.7 PRELIMINARY PAVEMENT D ESIGN ....................................................................... 25 5.8 SLOPE STABILITY ······························································································ 27 5.9 CONCRETE FLATWORK ...................................................................................... 27 5.10 SLOPE MAINTENANCE GUIDELINES ..................................................................... 27 5.11 LANDSCAPING AND POST-CONSTRUCTION ........................................................... 28 5.12 FUTURE INVESTIGATION ..................................................................................... 29 5 .13 CONSTRUCTION OBSERVATION AND TESTING AND PLAN REVIEW ........................... 30 6.0 LIMITATIONS ......................................................................................................... 31 TABLES TABLE 1 -EARTHWORK SHRINKAGE AND BULKING E STIMATES -PAGE 7 TABLE 2-CBC S EISMIC D ESIGN PARAMETERS -PAGE 11 TABLE 3-TEMPORARY EXCAVATION R ECOMMENDATIONS -PAGE 17 TABLE 4 -PRESOAKING R ECOMMENDATIONS BASED ON FINISH G RADE SOIL EXPANSION P OTENTIAL-PAGE 20 TABLE 5-P OST-T ENSIONED FOUNDATION D ESIGN R ECOMMENDATIONS -PAGE 22 TABLE 6 -STATIC EQUIVALENT FLUID W EIGHT (PCF)-PAGE 23 TABLE 7 -PRELIMINARY PAVEMENT S ECTION DESIGNS -PAGE -25 TABLE 8-PRELIMINARY CONCRETE PAVEMENT DESIGN -PAGE -26 F IGURE F IGURE 1 -SITE LOCATION MAP-R EAR OF TEXT ii I ,t "\ •-. ■ TABLE OF CONTENTS {Continued) Plate 1 -Geotechnical Map -In Pocket Plate 2 -Geologic Cross Section -In Pocket APPENDICES APPENDIX A -REFERENCES APPENDIX B -LABORATORY TESTING AND DENSITY TESTING BY OTHERS APPENDIX C -GENERAL EARTHWORK AND GRADING SPECIFICATIONS iii 042631-001 042631-001 1.0 INTRODUCTION 1.1 Purpose and Scope This report presents the results of our geotechnical update investigation for a proposed residential development to be constructed on the existing sheet graded parcel that is north of Rancho Santa Fe Road, south of Old Rancho Santa Fe Road, and west of Paseo Lupino in Carlsbad, California, (see Figure 1 ). Our investigation included a review of a previously Update Geotechnical Investigation and the As-Graded Geotechnical reports (SCS&T, 2012), and preparation of this report. The purpose of our geotechnical update investigation was to evaluate existing geotechnical conditions present at the site and to provide preliminary conclusions and geotechnical recommendations relative to the proposed residential development of the property. 1.1.1 Scope of Work As part of our geotechnical update, we performed the following: • Review of available pertinent, published and unpublished geotechnical literature maps, and aerial photographs (Appendix A). • Review of the available previous geotechnical reports by others and conceptual site development plans (SCS&T, 2012; Latitude 33, 2012). • Field reconnaissance of the existing onsite geotechnical conditions. • Review local and regional seismicity, and provide seismic parameters for the site in accordance with 201 O California Building Code (CBC). • An updated geotechnical map and geologic cross-section. • Preparation of this report presenting our findings, conclusions, and geotechnical recommendations with respect to the proposed design, site grading and general construction considerations. -1- 042631-001 1.2 Site Location and Description The proposed project is located north of Rancho Santa Fe Road, southeast of Old Rancho Santa Fe Road, and west of Paseo Lupino in Carlsbad, California. As background this parcel, was previously mass-graded pad (SCS&T, 2012), and has minor surface improvements consisting of a shallow concrete lined drainage ditches, a desilting basin, and landscaping of perimeter slopes extending down Old Rancho Santa Fe Road, Rancho Santa Fe Road, and along Paseo Lupino. The topography of the area is gently sloping with elevations ranging from approximately 380 feet mean sea level (msl) in the north corner to approximately 380 feet msl in the southeast corner and approximately 367 feet msl in the southwestern corner. Vegetation at the site consists of native grasses and weeds. Descending 2:1 fill slope, a fill over cut slope, a cut a slope all that borders the majority of the site except along a segment along Old Rancho Santa Fe Road in the northeastern section of the site. Latitude: 33.0839 degrees Longitude: -117 .2339 degrees 1.3 Previous Site Development and Site Grading As background, the site was rough graded in 2004 by Erreca's for Lusardi Construction. The grading was observed and tested by Southern California Soil & Testing (SCS&T, 2012). In general, grading consisted of installing keyways at the toe of several fill slopes, creation of cut and fill slopes, installation of a subrain trench backfill. Specifically, the grading consisted of excavating (i.e., cutting) the eastern portion of the site and placement of fill in the western portion of the site. Up to approximately 55 feet of fill was placed in the western portion of the site, while cut excavations extended up to approximately 31 feet below the previous existing grade at the eastern portion of the site. An overexcavation of the previously proposed building pads and parking area cut portion was performed into the underlying metavolcanic and replaced with capping fill material of less than 6 inches in diameter. Previously proposed building pads were overexcavated 2 to 7 feet below ground surface (bgs) and previously proposed parking areas were overexcavated to a minimum of 10 feet bgs and replaced with documented fill. Remedial grading consisted of removal of topsoil, alluvium, and existing fill to depth up to 25 feet below previous existing grades. In the southwest portion of the site, previous existing fills that were associated with -2- • 042631-001 grading and construction of Rancho Santa Fe Road were left-in-place. We have provided a geotechnical map (Plate 1) with approximate remedial grading and overexcavation elevations and limits of fill across the site. Note that blasting of the underlying formational bedrock was required in the eastern portion of the site. The resulting material, containing rock fragments of up to 2 feet in diameter was then m~isture conditioned and placed as fill. Fills placed within the upper 5 feet of previously proposed building pads and the upper 1 0 feet of previously proposed parking areas consisted of select capping material, comprised primarily of silty sand and sandy silt with variable clay and rock fragments generally no larger than 6 inches in diameter. Similar fill materials were used as compacted fill within the outermost 6 feet of fill slopes. This select capping material was derived from on-site non-organic topsoil and alluvial deposits, and some borrowed material from off-site sources. Excavations extending to metavolcanic rock were not scarified due to the nature of the exposed material. Excavated soils, cuts, and imported fill were placed as uniformly compacted fill material. The soils to be placed were moisture conditioned and compacted to a minimum of 90 percent relative compaction. 1.4 Proposed Development Based on our review of the conceptual site development plans (Latitude 33, 2012), we understand the proposed development will include construction of thirty-two single-family residential buildings and associated improvements including roadways, building patios, driveways, parking areas, concrete flatwork, underground utilities, landscaping, etc. We also understand that the proposed buildings will be two story structures and will likely be constructed with conventional or post-tension foundations. Based on the preliminary development plans, we anticipate the proposed finish grade elevations will be within a 1 to 4 feet of the existing mass-graded pad elevations. -3- , ' ■ 042631-001 1.5 Previous Laboratory Testing Laboratory testing was performed during the previous site grading to evaluate maximum density and expansion index characteristics of the subsurface soils. The previous laboratory tests performed by Southern California Soil & Testing (SCS&T, 2012) are presented in Appendix B. -4- • I ■ 042631-001 2.0 SUMMARY OF GEOTECHNICAL CONDITIONS 2.1 Geologic Setting The subject site is located in the coastal section of the Peninsular Range Province, a geomorphic province with a long and active geologic history throughout Southern California. Throughout the last 54 million years, the area known as the "San Diego Embayment" has undergone several episodes of marine inundation and subsequent marine regression, resulting in the deposition of a thick sequence of marine and nonmarine sedimentary rocks on the basement rock of the Southern California batholith. Gradual emergence of the region from the sea occurred in Pleistocene time, and numerous wave-cut platforms, most of which were covered by relatively thin ma rine and nonmarine terrace deposits, formed as the sea receded from the land. Accelerated fluvial erosion during periods of heavy rainfall, coupled with the lowering of the base sea level during Quaternary time, resulted in the rolling hills, mesas, and deeply incised canyons which characterize the landforms we see in the general site area today. 2.2 Site-Specific Geology Based on our review of the previous site geotechnical documents, a site reconnaissance, and review of pertinent geologic literature and maps, the site is generally underlain by documented artificial fill soils and the Jurassic-aged Santiago Peak Volcanics. A brief description of the geologic units at the site are presented below. 2.2.1 Artificial Fill -Previously Existing (Afo) Artificial fill placed during the previous grading operations along Rancho Santa Fe Road. This fill is present below the fill slopes at the western end of the site. As described, this fill generally consists of reddish-brown to brown, medium dense to dense, moist, silty sands with clays, gravel, and cobble. The estimated depth of fill beneath the existing slope faces should be no greater than 1 O feet below the adjacent roadway surface. These artificial fills are expected to be suitable to support the proposed residential development. -5- ■ 042631-001 2.2.2 Artificial Fill -Documented (Af) Artificial fill placed during the previous site mass grading is anticipated to be present throughout the entire site. The documented fill generally consist of reddish-brown to brown, medium dense to dense, moist, silty sands with clays, gravel, and cobble. The estimated depth of fill beneath the existing site grades ranges from approximately 1.5 to 55 feet below the existing surface grades. These artificial fills are expected to be suitable to support the proposed residential development; although minor reconditioning and/or removal of loose desiccated surficial soils may be necessary. We have provided density tests and laboratory testing (SCS&T, 2012) in Appendix B. 2.2.3 Santiago Peak Volcanics (Jsp) Santiago Peak metavolcanic rock outcrops were observed across the eastern portion of the site and underlie the entire site. The rock generally consisted of light gray-olive brown to reddish brown, damp, highly fractured, moderately to highly weathered metavolcanic rock. Where observed, the metavolcanic rock becomes fresh bedrock is anticipated within 2 feet to 1 O feet of the surface. Excavations and cuts (greater than ±2 feet at the east end of the site will likely require very heavy ripping and/or blasting and will likely generate some oversized materials. Fresh rock zones may also be encountered at shallower depths. Additional subsurface exploration is recommended to further evaluate depth bedrock beneath the site. 2.3 Geologic Structure Based on our review of the as-graded geotechnical report, and regional geologic maps, the Jurassic-aged Santiago Peak Volcanics have a regional northwesterly foliation/fracturing trend in the metavolcanic rock bedding and generally flat bedding where present. Jointing was generally oriented parallel to previous existing slopes with steep to moderate dip. -6- • 042631 -001 2.4 Surface and Ground Water No indication of surface water or evidence of surface ponding was encountered during our review. However, surface water may drain as sheet flow in the higher portions of the site during rainy periods and sheet across the lower portions of the site. Ground water was not reported during the original mass grading. Ground water levels are anticipated to be relatively deep; however, perched ground water conditions may develop following site development at contact areas of artificial fill and the underlying bedrock. Ground water is not expected to impact the proposed development. 2.5 Landslides No ancient landslides were identified beneath or adjacent to the site. In addition, no evidence of landsliding was documented during mass grading of the site. The potential for significant landslides or large-scale slope instability at the site is considered low. 2.6 Flood Hazard According to a Federal Emergency Management Agency (FEMA) flood insurance rate map (FEMA, 1997); the site is not located within a flood zone. Based on review of dam inundation and topographic maps per SANGIS, the site is not located downstream from dam inundation areas. 2.7 Engineering Characteristics of the On-Site Soils Based on our review of previous site reports laboratory testing of representative on-site soils and our professional experience on near-by sites with similar soils, the engineering characteristics of the on-site soils are discussed below. 2.7.1 Expansion Potential The majority of the onsite soils are expected to have a medium to high expansion potential. The expansion index tests performed after site grading ranged from 54 to 91 (SCS&T, 2012). Previous expansion index testing is provided in Appendix B. Geotechnical observation and/or laboratory testing -7- I 042631-001 upon completion of the anticipated fine grading operations are recommended to determine the actual expansion potential of finish grade soils on the site. 2.7.2 Earthwork Shrinkage and Bulking Based on our professional experience with similar projects in the general vicinity of the site, we have estimated bulking and shrinkage of the on-site soils. The volume change of excavated on-site materials upon recompaction as fill is expected to vary with materials and location. Typically, the surficial soils and bedrock materials vary significantly in natural and compacted density, and therefore, accurate earthwork shrinkage/bulking estimates cannot be determined. However, the following factors (based on professional experience on nearby sites) are provided on Table 1 as guideline estimates. If possible, we suggest an area where site grades can be adjusted (during the later portion of the site grading operations) be provided as a balance area. Table 1 Earthwork Shrinkage and Bulking Estimates Geologic Unit Estimated Shrinkage/Bulking Documented and Existing Fills O to 3 percent shrinkage Metavolcanic Rock (highly weathered) 0 to 1 O percent bulking Metavolcanic Rock (less-weathered) 5 to 15 percent bulking 2. 7 .3 Excavation Characteristics It is anticipated the onsite fill soils can be excavated with conventional heavy-duty construction equipment. However, excavations deeper than 5 feet, especially in the eastern portion of the site, is expected to be marginally to nonippable in some area or will need to be blasted prior to excavation. Note that based on the current grading plans and review of the existing or previously pad overexcavation limits, portions of the site will require additional overexcavation of rock to depths of at least 4 feet below finish grade. Note that the overexcavation will be within metavolcanic rock and -8- • ♦ t'\ • 042631 -001 may require heavy ripping or blasting. The approximate limits of anticipated metavolcanic rock overexcavation is depicted on Geotechnical Map (Plate 1 ). Also note that large rock may be generated during overexcavation and the rock may have to be hauled off site or buried in deep fill areas on the site. Additional subsurface exploration should be performed to further characterize the bedrock. 2. 7.4 Oversize Material Numerous exposures of jointed metavolcanic bedrock occur across the site. On average the jointed rock is anticipated to yield approximately one foot diameter blocks with a potential for larger boulders. Based on our professional experience with projects in similar geologic conditions, it is likely that oversized rock will be generated during grading. Recommendations have been provided for appropriate handling of oversized materials. -9- L.i.:"1 1• 042631-001 3.0 FAUL TING AND SEISMICITY 3.1 Faulting Our discussion of faults on the site is prefaced with a discussion of California legislation and state policies concerning the classification and land-use criteria associated with faults. By definition of the California Mining and Geology Board, an active fault is a fault which has had surface displacement within Holocene· time (about the last 11,000 years). The state geologist has defined a potentially active fault as any fault considered to have been active during Quaternary time (last 1,600,000 years). This definition is used in delineating Earthquake Fault Zones as mandated by the Alquist-Priolo Earthquake Faulting Zones Act of 1972 and as most recently revised in 2007 (Hart and Bryant, 2007). The intent of this act is to assure that unwise urban development and certain habitable structures do not occur across the traces of active faults. Based on our review, the site is not located within any Earthquake Fault Zone (EFZ) as created by the Alquist-Priolo Act. A review of available geologic literature pertaining to the subject site indicates that there are no known active regional faults that transect the subject site. The nearest known active regional fault is the Rose Canyon Fault Zone located approximately 7.1 miles west of the site. 3.2 Seismicity The principal seismic considerations for most structures in southern California are surface rupturing of fault traces and damage caused by strong ground shaking or seismically induced ground settlement. Historically, the San Diego region has been spared major destructive earthquakes. The site is considered to lie within a seismically active region, as can all of Southern California. The effect of seismic shaking may be mitigated by adhering to the California Building Code (see Section 3.2.6 of this report for CBC seismic parameters) or state-of-the-art seismic design parameters of the Structural Engineers Association of California. Secondary effects associated with severe ground shaking following a relatively large earthquake can include shallow ground rupture, soil liquefaction, lateral spreading, earthquake-induced settlement, and tsunamis/seiches. These secondary effects of seismic shaking are discussed in the following sections. ~~ -10-_, l I ' t • ■ 042631-001 3.2.1 Shallow Ground Rupture No active faults are mapped crossing the site. The nearest known active fault is the Rose Canyon 7 .1 miles west of the site. Due to absence of known active faults, cracking due to shaking of a seismic event is not considered a significant hazard, although it is possible at any site. 3.2.2 Liquefaction Liquefaction and dynamic settlement of soils can be caused by strong vibratory motion due to earthquakes. Both research and historical data indicate that loose, saturated, granular soils are susceptible to liquefaction and dynamic settlement. Liquefaction is typified by a total loss of shear strength in the affected soil layer, thereby causing the soil to flow as a liquid. This effect may be manifested by excessive settlements and sand boils at the ground surface. The unsaturated artificial fill and formational materials that underlie the site are not considered liquefiable due to their dense physical characteristics and lack of ground water. 3.2.3 Earthquake-Induced Settlement Granular soils tend to density when subjected to shear strains induced by ground shaking during earthquakes. Simplified methods were proposed by Tokimatsu and Seed (1987) and Ishihara and Yoshimine (1992) involving SPT N-values to estimate earthquake-induced soil settlement. However, since liquefaction at the site is considered low, there is relatively no potential for earthquake-induced settlements. 3.2.4 Lateral Spread Empirical relationships have been derived by Youd and others (Youd, 1993; Bartlett and Youd , 1995; and Youd et. al., 1999) to estimate the magnitude of lateral spread due to liquefaction. These relationships include parameters such as earthquake magnitude, distance of the earthquake from the site, slope height and angle, the thickness of liquefiable soil, and gradation characteristics of the soil. -11 - 042631 -001 Since there is relative no potential for liquefaction at the site, there is no susceptibility to earthquake-induced lateral spread. 3.2.5 Tsunamis and Seiches Based on the distance between the site and large, open bodies of water, barriers between the site and the open ocean, and the elevation of the site with respect to sea level, the possibility of seiches and/or tsunamis is considered to be nil. 3.2.6 Building Code Seismic Parameters The following geotechnical design parameters have been determined in accordance with the 2010 CBC (CBSC, 2010) and the USGS Ground Motion Parameter Calculator (Version 5.10). Table 2 CBC Seismic Design Parameters Description Values CBC Reference Site Class D Table 1613.5.2 Short Period Spectral Acceleration Ss 1.118 Figure 1613.5(3) 1-Second Period Spectral Acceleration S1 0.420 Figure 1613.5(4) Short Period Site Coefficient Fa 1.053 Table 1613.5.3(1) 1-Second Period Site Coefficient Fv 1.58 Table 1613.5.3(2) Adjusted Short Period Spectral SMs 1.177 Equation 16-36 Acceleration Adjusted 1-Second Period Acceleration SM1 0.663 Equation 16-37 Design Short Period Spectral Sos 0.785 Equation 16-38 Response Parameter Design 1-Second Period Spectral So1 0.442 Equation 16-39 Response Parameter -12- I 042631-001 4.0 CONCLUSIONS Based on our review of the previously documented Update Geotechnical Investigation and As-Graded Geotechnical reports (SCS&T, 2012), it is our professional opinion that the proposed development of the site is feasible from a geotechnical standpoint, provided the following conclusions and recommendations are incorporated into the design, grading, and construction of the project. Additional subsurface exploration should be performed to further characterize the bedrock beneath the site. The following is a summary of the geotechnical factors that may affect development of the site. • Based on our reference review, the documented fill and underlying formational material are dense and well compacted, excluding the upper 1 to 2 feet which appears dry and is disturbed and/or weathered. The upper 2 feet of existing fill is considered unsuitable for support of additional fill soils, structural loads or surface improvements in their present condition. Remedial grading measures such as removals, scarification and recompaction will be necessary to mitigate this condition, if not removed by the proposed grading. • Based on the review of the as-graded documents, minimum fill depths across mass- graded pad below the existing ground surface are on the order of approximately 2 feet beneath the proposed building footprints. Because site grades are being lowered a cuUfill transition will be created and additional overexcavation will be required. The pad overexcavations will encounter metavolcanic rock with oversized rock material. • Based on previous laboratory testing, the near surface soils on the site generally possess a medium to high expansion potential. Measures to mitigate expansive/swelling soils will be necessary during design and construction. Additional expansion testing should be performed after pad grading is performed. • Laboratory tests should be conducted to determine the onsite soils' potential for sulfate exposure on concrete once pad grading is performed. • The existing onsite soils appear to be suitable material for use as fill provided they are relatively free of organic material, debris, and rock fragments larger than 8 inches in maximum dimension. Review of the as-graded report indicates that some oversized material was generated during site grading but placed below proposed foundation grades. However, in areas where proposed pad grades are lowered and -13- t - 042631 -001 deep utility excavations are planned, especially outside the previous pad overexcavations (building and parking lot), oversized metavolanic rock should be anticipated. Oversize material if encountered should be placed in nonstructural areas or disposed of offsite. • Ground water or seepage was not encountered during the previous site grading or investigations (SCS&T, 2012); however, perched ground water and seepage may develop during periods of precipitation. • The site is located in an area underlain by the fill and formational material that is known to contain both permeable and impermeable layers which can transmit and perched ground water in unpredictable ways. Therefore, given the site geologic conditions, the use of some LID measures may not be appropriate for this project. -14- L , .. ·! 042631 -001 5.0 RECOMMENDATIONS 5.1 Earthwork We anticipate that earthwork at the site will consist of site preparation, remedial grading and placement of compacted fill. We recommend that earthwork on the site be performed in accordance with the following recommendations and the General Earthwork and Grading Specifications for Rough Grading included in Appendix C. In case of conflict, the following recommendations shall supersede those in Appendix C. 5.1.1 Site Preparation Prior to grading of areas to receive structural fill or engineered structures and improvements. the areas should be cleared of surface vegetation, any existing debris, and removal of potentially compressible material, which includes the existing upper 1 to 2 feet of disturbed/weathered fill. Vegetation and debris should be removed and properly disposed of offsite. Holes resulting from the removal of buried obstructions, which extend below finished site grades, should be replaced with suitable compacted fill material. Areas to receive fill and/or other surface improvements should be scarified to a minimum depth 8 inches, brought to above-optimum moisture condition, and recompacted to at least 90 percent relative compaction (based on American Standard of Testing and Materials [ASTM] Test Method 01557). A Leighton representative should observe conditions exposed in the bottom of the excavation to determine if additional removal is required. 5.1.2 Excavations and Oversize Material Based on the review of previous site reports and our site reconnaissance, it appears that the near surface fill is rippable with heavy-duty construction equipment in good working order (i .e. a single shank D9 Dozer or equivalent). However, moderately difficult ripping to very difficult ripping and localized blasting should be anticipated where Santiago Peak Volcanic Rock is mapped near the surface, in the fill areas between 2 to 5 feet below the ground surface on the central and eastern portions of the site, and where proposed pad grades are lower than existing grade. Deeper excavations into the rock is expected to be marginally rippable to -15- L - 042631-001 unrippable, becoming progressively less fractured with increasing depth. Heavy/very difficult to unrippable and blasting is anticipated for planned excavations below a depth of 2 feet and for localized areas within 10 feet on the ground surface. Note previous cut-graded portions of the site will likely encounter heavy/very difficult to unrippable rock significantly shallower than anticipated. Localized residual boulders of dense rock are also anticipated within otherwise rippable zones. The depth of mass- graded pad overexcavation to metavolcanic rock and at grade metavolcanic rock is displayed on the Geotechnical Map (Plate 1 ). We understand that a portion of the site was overexcavated at the previous proposed building pads and parking lot area, and were generally capped with material not exceeding 6 inches in diameter. Outside the limits of the previously overexcavated parking lot and proposed building pads significant amount of rock including oversize material (i.e. rock typically over 8 inches in maximum dimension) will be generated during the grading of the site. Rocks greater than 8 inches in diameter should not be placed within fill the upper three of fill. Note that the western portion of the site (i.e. outside the limits of the previously proposed pads and parking lot overexcavation) it is unknown if the fills near pad grade was capped with material less 6 inches in diameter. Excavations in western portion of the site should anticipate oversized rock material. All oversized rock that is encountered should be placed as fill in accordance with the recommendations in section 5.2 or hauled off site for disposal. 5.1.3 Fill Placement The onsite soils are generally suitable for reuse as compacted fill, provided they are free of organic materials and debris. Areas to receive structural fill and/or other surface improvements should be scarified to a minimum depth of 8 inches; brought to at least 3 percent above optimum moisture content; and recompacted to at least 90 percent relative compaction (based on ASTM Test Method D1557). The optimum lift thickness to produce a uniformly compacted fill will depend on the type and size of compaction equipment used. In general, fill should be placed in uniform lifts not exceeding 8 inches in thickness. Placement and compaction of fill should be performed in general accordance with the current City of Carlsbad grading ordinances under the observation and testing of the geotechnical -16- [_ I 042631-001 consultant, sound construction practices, and the General Earthwork and Grading Specifications for Rough Grading presented in Appendix C. Proposed fills placed on slopes steeper than 5 to 1 (horizontal to vertical) and repairs of the existing fill slopes should be keyed and benched into dense formational or competent fill soils (see Appendix C for benching details). Fills placed within 5 feet of finish pad grades should consist of granular soils of very low to medium expansion potential and contain no materials over 8 inches in maximum dimension. Oversize material, if encountered, may be incorporated into structural fills if placed in accordance with the recommendation of Appendix C. Import soils, if necessary, should consist of granular soils of very low to low expansion potential (expansion index 50) and contain no materials over 8 inches in maximum dimension. 5.1.4 Cut/Fill Transition Mitigation and Pad Overexcavation In order to reduce the potential for differential· settlement in areas of transition or cut-fill building pads and to remove metavolcanic rock in cut areas, we recommend that the entire cut portion of the building pad be overexcavated to a minimum depth of 4 feet below finished grade and replaced with properly compacted fill. This depth may be increased depending on adjacent fill depth as part of the recommended removals of artificial fill beneath the building pads. The overexcavation and recompaction should laterally extend at least 5 feet beyond limits of the building footprint. Based on our review of the preliminary plans, we provided an approximate location of building pads overexcavations (Plate 1 ). In order to reduce the potential for excessive differential settlement under future building or retaining walls, the transition from cut to fill subgrade should be gradual. We recommend that the maximum differential fill height to not exceed 1 O feet over a horizontal distance of 30 feet. The actual overexcavation limits and depth should be further evaluated prior to the grading operations based on the final design of the project and the actual building location and dimension. Also, additional over-excavation or deeper removals may be recommended during site grading based on the actual field conditions. -17- 042631-001 5.2 Rock Fill Specifications We anticipate that the relatively shallow cuts on the mass graded pad that will generate oversized rock. Fill placement 1 foot below deepest utilities in roadways and within the upper 3 feet of finish grade, fill soils should not contain rock greater than 8 inches in maximum dimension in order to facilitate foundation and utility trench excavation. For fill soils between 3 and 1 0 feet below finish grade, the fill may contain rock up to 12 inches in maximum dimension and should be mixed with sufficient soil to eliminate voids. Below a depth of 1 0 feet and at least 3 feet horizontally from the slope face, rocks up to a maximum dimension of 36 inches may be incorporated into the fill utilizing rock blankets. A typical soil- rock fill detail is included within Appendix C. Rocks up to 5 feet in maximum dimension should be hauled offsite or utilized in nonstructural fill or landscaped area. 5.3 Temporary Excavations Sloped excavations may be utilized when adequate space allows. Based on findings, we provide the following recommendations for sloped excavations in fill soils or competent bedrock materials without seepage conditions. Table 3 Temporary Excavation Recommendations Excavation Maximum Slope Ratio Depth Below Maximum Slope Ratio Adjacent Surface In Fill Soils In Competent Bedrock (feet) Material Oto 5 ¾:1 (H : V) Vertical 5 to 20 1:1 1/2:1 Excavations greater than 20 feet in height will require an alternative sloping plan or shoring plan prepared by a California registered civil engineer. The above values are based on the assumption that no surcharge loading or equipment will be placed within 10 feet of the top of slope. All excavations should comply with OSHA requirements The contractor's "competent person" should review all excavations on a daily basis for signs of instability. -18- '. 042631-001 5.4 Surface Drainage and Erosion Surface drainage should be controlled at all times. Proposed structures should have an appropriate drainage system to collect roof runoff. Positive surface drainage should be provided to direct surface water away from structures toward the street or suitable drainage facilities. Planters should be designed with provisions for drainage to the storm drain. Ponding of water should be avoided adjacent to any structures. Regarding Low Impact Development (LID) measures, we are of the opinion that bioswales, infiltration basins, and other onsite retention and infiltration systems can potentially create adverse perched ground water conditions both on-site and off- site. In particular, this site is underlain by fill or formations that are known to contain both permeable and impermeable layers which can transmit and perch ground water in unpredictable ways. Therefore, given the site geologic conditions and project type, some types of LID measures may not be appropriate for this site and project. We recommend that infiltration systems are lined with a 15 mil HOPE impermeable liner. 5.5 Foundation and Slab Considerations Foundations and slabs should be designed in accordance with structural considerations and the following recommendations. These recommendations assume that the soils encountered within 5 feet of pad grade have a medium to high expansion potential (i.e. an expansion index less than 130) for expansion and a differential fill thickness of less than 15 feet. Additional expansion testing should be performed as part of the fine grading operations. If very high expansive soils are encountered and selective grading cannot be accomplished, additional foundation design may be necessary. 5.5.1 Preliminary Foundation and Slab Design The proposed buildings may be supported by conventional, continuous or isolated spread footings. Footings should extend a minimum of 30 inches beneath the lowest adjacent soil grade. At these depths, footings may be designed for a maximum allowable bearing pressure of 2,500 pounds per square foot (psf) if founded in dense compacted fill soils. The allowable bearing pressures may also be increased by one-third when considering loads of short duration such as wind or seismic forces. The minimum -19- l -I : ' • 042631-001 recommended width of footings is 18 inches for continuous footings and 24 inches for square or round footings. Footings should be designed in accordance with the structural engineer's requirements. We recommend a minimum horizontal setback distance from the face of slopes for all structural footings and settlement-sensitive structures. This distance is measured from the outside edge of the footing, horizontally to the slope face (or to the face of a retaining wall) and should be a minimum of H/2, where H is the slope height (in feet). The setback should not be less than 1 0 feet and need not be greater than 20 feet. Please note that the soils within the structural setback area, other than those addressed within this report, possess poor lateral stability, and improvements (such as retaining walls, sidewalks, fences, pavements, etc.) constructed within this setback area may be subject to lateral movement and/or differential settlement. Slabs on grade should be reinforced with reinforcing bars placed at slab mid-height. Slabs should have crack· joints at spacings designed by the structural engineer. Columns, if any, should be structurally isolated from slabs. Slabs should be a minimum of 5 inches thick and reinforced with No. 4 rebars at 18 inches on center on center (each way). If applicable, slabs should also be designed for the anticipated traffic loading using a modulus of subgrade reaction of 100 pounds per cubic inch. All waterproofing measures should be designed by the project architect. In accordance with the current guidelines of the 2010 CAL Green Code, Section 4.505.2, post-tensioned and conventional slabs should be underlain by a vapor barrier which is in turn underlain by 4 inches of 1/2 inch gravel. The slab subgrade soils should be presoaked prior to the placement of gravel. ACI 302.2R-06 guidance recommends use of a vapor barrier with a perm rating of 0.01 or less where moisture-sensitive floor coverings are provided. The vapor barrier should possess adequate puncture resistance such that these properties are preserved when subjected to construction traffic. Placement of concrete in direct contact with the vapor barrier requires additional design and construction considerations on the part of the structural engineer, architect and contractor. Additional guidance is -20- • 042631-001 provided in ACI Publications 302.1 R-04 Guide for Concrete Floor and Slab Construction and 302.2R-06 Guide for Concrete Slabs that Receive Moisture-Sensitive Floor Materials. Only an experienced concrete contractor familiar with proper construction techniques needed for constructing slabs directly on the vapor retarder/barrier should perform the work. The slab subgrade soils underlying the foundation systems should be presoaked in accordance with the recommendations presented in Table 4 prior to placement of the moisture barrier and slab concrete. The subgrade soil moisture content should be checked by a representative of Leighton prior to slab construction. Presoaking or moisture conditioning may be achieved in a number of ways. But based on our professional experience, we have found that minimizing the moisture loss on pads that has been completed (by periodic wetting to keep the upper portion of the pad from drying out) and/or berming the lot and flooding for a short period of time (days to a few weeks) are some of the more efficient ways to meet the presoaking recommendations. If flooding is performed, a couple of days to let the upper portion of the pad dry out and form a crust so equipment can be utilized should be anticipated. Table 4 Presoaking Recommendations Based on Finish Grade Soil Expansion Potential Expansion Potential Presoaking Recommendations Very Low Near-optimum moisture content to a minimum depth of6inches Low 120 percent of the optimum moisture content to a minimum depth of 12 inches below slab subgrade Medium 130 percent of the optimum moisture content to a minimum depth of 24 inches below slab subgrade High 130 percent of the optimum moisture content to a minimum depth of 30 inches below slab subgrade -21- 042631-001 5.5.2 Settlement Fill depths between 2 and 55 feet are anticipated beneath the proposed building footings following final grading. Based on this configuration, the maximum total settlement is estimated at approximately 1 inch with differential settlement anticipated to be approximately ¾ to 1 inch over a horizontal distance of 100 feet. 5.5.3 Post-Tension Foundation Recommendations As an alternative to the conventional foundations for the buildings, post- tensioned foundations may be used. We recommend that post-tensioned foundations be designed using the geotechnical parameters presented in table below and criteria of the 201 0 California Building Code and the Third Edition of Post-Tension Institute Manual. A post-tensioned foundation system designed and constructed in accordance with these recommendations is expected to be structurally adequate for the support of the buildings planned at the site provided our recommendations for surface drainage and landscaping are carried out and maintained through the design life of the project. Based on an evaluation of the depths of fill beneath the building pads, the attached Table 5 presents the recommended post-tension foundation category for residential buildings on subject site. -22- ■ 042631-001 Table 5 Post-Tensioned Foundation Design Recommendations Category I Category II Category Ill Very Low to Low Medium Expansion High Expansion Expansion Potential Potential Potential Design Criteria (El Oto 50) (El 51 to 90) (El 91 to 130) Differential Fill Differential Fill Differential Fill Thickness less Thickness between Thickness between than 10 feet 1 0 and 20 feet 20 and 40 feet 9.0 feet 8.3 feet 7.0 feet Edge Moisture Center Lift: Variation, em Edge Lift: 4.8 feet 4.2 feet 3.7 feet 0.75 inches 1.09 inches Differential Swell, Center Lift: 0.46 inches Ym Edge Lift: 0.65 inches 1.09 incfies 1.65 inches Perimeter Footing Depth: 18inches 24inches 30inches Allowable Bearing Capacity 2,000 psf The post-tensioned (PT) foundation and slab should also be designed in accordance with structural considerations. For a ribbed PT foundation, the concrete slabs section should be at least 5 inches thick. Continuous footings (ribs or thickened edges) with a minimum width of 12 inches and a minimum depth of 12 inches below lowest adjacent soil grade may be designed for a maximum allowable bearing pressure of 2,000 pounds per square foot. For a uniform thickness "mat" PT foundation, the perimeter cut off wall should be at least 8 inches below the lowest adjacent grade. However, note that where a foundation footing or perimeter cut off wall is within 3 feet (horizontally) of adjacent drainage swales, the adjacent footing should be embedded a minimum depth of 12 inches below the swale flow line. The allowable bearing capacity may be increased by one-third for short-term loading. The slab subgrade soils should be presoaked in accordance with the recommendation presented in Table 4 above prior to placement of the moisture barrier. -23- 042631-001 The slab should be underlain by a moisture barrier as discussed in Section 5.51 above. Note that moisture barriers can retard, but not eliminate moisture vapor movement from the underlying soils up through the slabs. We recommend that the floor covering installer test the moisture vapor flux rate prior to attempting applications of the flooring. "Breathable" floor coverings should be considered if the vapor flux rates are high. A slip-sheet or equivalent should be utilized above the concrete slab if crack-sensitive floor coverings (such as ceramic tiles, etc.) are to be placed directly on the concrete slab. Additional guidance is provided in ACI Publications 302.1 R-04 Guide for Concrete Floor and Slab Construction and 302.2R-06 Guide for Concrete Slabs that Receive Moisture-Sensitive Floor Materials. Based on an overall geotechnical evaluation of the El values and their locations, we anticipate Post-Tension Foundation Category II and Ill for the site. 5.6 Retaining Wall Design and Lateral Earth Pressure We anticipate that several relatively small retaining walls are proposed at the site. For design purposes, the following lateral earth pressure values for level or sloping backfill are recommended for retaining walls backfilled with onsite soils of medium to high expansion potential (expansion potential greater than 50 per ASTM Test Method 04829). Table 6 Static Equivalent Fluid Weight (pcf) Conditions Level 2:1 Slope - Active 40 65 At-Rest 55 90 300 140 Passive (Maximum of 3 ksf) (Sloping Down) Unrestrained (yielding) cantilever walls up to 15 feet in height should be designed for an active equivalent pressure value provided in table above. For the design of walls restrained from movement at the top (nonyielding) such as basement walls, the at-rest pressures should be used. If conditions other than those covered herein are anticipated, the equ ivalent fluid pressure values should be provided on -24- ". ■ 042631-001 an individual case basis by the geotechnical engineer. A surcharge load for a restrained or unrestrained wall resulting from automobile traffic may be assumed to be equivalent to a uniform horizontal pressure of 75 psf which is in addition to the equivalent fluid pressure given above. For other uniform surcharge loads, a uniform horizontal pressure equal to 0.35q should be applied to the wall (where q is the surcharge pressure in psf). To account for potential redistribution of forces during a seismic event, basement walls, if any, that fall within the requirements of ASCE 7-05 Section 15.6.1 should also be checked considering an additional uniform seismic pressure distribution equal to 1 OH psf, where H equals the overall retained height in feet. The wall pressures assume walls are backfilled with free draining materials and water is not allowed to accumulate behind walls. A typical wall drainage design is provided in Appendix D. Importing or selective grading may be necessary to obtain retaining wall backfill material. Wall backfill should be brought to at least 3 percent above the optimum moisture content and compacted by mechanical methods to at least 90 percent relative compaction (based on ASTM D1557). Wall footings should be designed in accordance with the foundation design recommendations and reinforced in accordance with structural considerations. The bearing pressure for retaining walls should be limited to 2,500 psf for footing founded in compacted fill. Footing embedment depth should be at least 18 inches below the lowest adjacent grade. For all retaining walls, we recommend a minimum horizontal distance from the outside base of the footing to daylight of 10 feet. Lateral soil resistance developed against lateral structural movement can be obtained from the passive pressure value provided above. Further, for sliding resistance, the friction coefficient of 0.33 may be used at the concrete and soil interface. These values may be increased by one-third when considering loads of short duration including wind or seismic loads. The total resistance may be taken as the sum of the frictional and passive resistance provided that the passive portion does not exceed two-thirds of the total resistance. 5.7 Preliminary Pavement Design The appropriate pavement section will depend on the type of subgrade soil, shear strength, traffic load, and planned pavement life. Since an evaluation of the actual subgrade soils cannot be made at this time, we have used an assumed R-value of 15 and Traffic Indices (Tl) of 4.5, 5 and 6 for the parking/auto driveways and truck -25- L ■ 042631-001 driveways, respectively. The range of onsite pavement sections presented on Table 7 is to be used for preliminary planning purposes only. Final pavement designs should be completed after R-value tests have been performed on actual subgrade materials. Table 7 Preliminary Pavement Section Designs Traffic Index Preliminary Pavement Section 4.5 4 inches AC over 5 inches Class 2 Aggregate Base 5 4 inches AC over 6 inches Class 2 Aggregate Base 6 4 inches AC over 12 inches Class 2 Aggregate Base Prior to placing the pavement section, the subgrade soils should have a relative compaction of at least 95 percent to a minimum depth of 12 inches (based on ASTM Test Method D1557). Aggregate Base should be compacted to a minimum of 95 percent relative compaction (based on ASTM Test Method D1557) prior to placement of the AC. All concrete pavement sections, including concrete curbs and gutters, should be underlain by at least 6 inches of aggregate base (AB) compacted to 95 percent relative compaction. The Asphalt Concrete (AC) and Class 2 Aggregate Base shall conform to and be placed in accordance with the latest revision of the California Department of Transportation Standard Specifications (Section 26), the Greenbook specifications, and/or the City of Carlsbad requirements. Asphalt Concrete shall conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. The following table presents recommendations for the concrete pavement sections subject to vehicle loading. Subgrade soils are assumed to have an R-value of least 15 and compacted to at least 95 percent relative compaction. -26- I .·,1 I '-'- • 042631-001 Table 8 Preliminary Concrete Pavement Design Traffic Index Minimum PCC Section (MR = 600 psi min.) 5 6.5 inches PCC 6 7.0 inches PCC 5.8 Slope Stability It is our understanding that the existing slopes up to 35 feet in height will remain. Based on our experience and observation of the performance of similar smaller slopes in the site area, it is our opinion that the existing 2 to 1 (horizontal to vertical) slopes, will be grossly stable. 5.9 Concrete Flatwork Concrete sidewalks and other flatwork (including construction joints) should be designed by the project civil engineer and should have a minimum thickness of 4 inches. For all concrete flatwork, the upper 12 inches of subgrade soils should be moisture conditioned to at least 3 to 6 percent above optimum moisture content depending on the soil type and compacted to at least 90 percent relative compaction based on ASTM Test Method D1557 prior to the concrete placement. For all concrete flatwork driveways and sidewalks, the subgrade soils should be should also be presoaked as discussed in Table 4 above prior to placement of concrete, and should contain reinforcement steel with dowels into existing adjacent concrete to the concrete placement. Moisture testing by Leighton should be performed 24 hours prior to concrete placement. 5.10 Slope Maintenance Guidelines It is the responsibility of the owner or owner's association to maintain the slopes, including adequate planting, proper irrigation and maintenance, and repair of faulty irrigation systems. To reduce the potential for erosion and slumping of graded slopes, all slopes should be planted with ground cover, shrubs, and plants that develop dense, deep root structures and require minimal irrigation. Slope planting should be carried out as soon as practical upon completion of -27- L ■ 042631-001 grading. Surface-water runoff and standing water at the top-of-slopes should be avoided. Oversteepening of slopes should also be avoided during construction activities and landscaping. Maintenance of proper drainage, undertaking of improvements in accordance with sound engineering practices, and proper maintenance of vegetation, including regular slope irrigation, should be performed. Slope irrigation sprinklers should be adjusted to provide maximum uniform coverage with minimal of water usage and overlap. Overwatering and consequent runoff and ground saturation should be avoided. If automatic sprinklers systems are installed, their use must be adjusted to account for rainfall conditions. Trenches excavated on a slope face for any purpose should be properly backfilled and compacted in order to obtain a minimum of 90 percent relative compaction, in accordance with ASTM Test Method D1557. Observation/testing by the geotechnical consultant during trench backfill are recommended. A rodent- control program should be established and maintained. Prior to planting, recently graded slopes should be temporarily protected against erosion resulting from rainfall, by the implementing slope protection measures such as polymer covering, jute mesh, etc. 5.11 Landscaping and Post-Construction Landscaping and post-construction practices carried out by the owner and their representatives exert significant influences on the integrity of structures founded on expansive soils. Improper landscaping and post-construction practices, which are beyond the control of the geotechnical engineer, are frequently the primary cause of distress to these structures. Recommendations for proper landscaping and post-construction practices are provided in the following paragraphs within this section. Adhering to these recommendations will help in minimizing distress due to expansive soils, and in ensuring that such effects are limited to cosmetic damages, without compromising the overall integrity of structures. Initial landscaping should be done on all sides adjacent to the foundation of a structure or associated improvements, and adequate measures should be taken to ensure drainage of water away from the foundation or improvement. If larger, shade providing trees are desired, such trees should be planted away from structures or improvements (at a minimum distance equal to half the mature height -28- • 042631-001 of the tree) in order to prevent penetration of the tree roots beneath the foundation of the structure or improvement. Locating planters adjacent to buildings or structures should be avoided as much as possible. If planters are utilized in these locations, they should be properly designed so as to prevent fluctuations in the moisture content of the subgrade soils .. Planting areas at grade should be provided with appropriate positive drainage. Wherever possible, exposed soil areas should be above paved grades. Planters should not be depressed below adjacent paved grades unless provisions for drainage, such as catch basins and drains, are made. Adequate drainage gradients, devices, and curbing should be provided to prevent runoff from adjacent pavement or walks into planting areas. Watering should be done in a uniform, systematic manner as equally as possible on all sides of the foundation, to keep the soil moist. Irrigation methods should promote uniformity of moisture in planters and beneath adjacent concrete flatwork. Overwatering and underwatering of landscape areas must be avoided. Areas of soil that do not have ground cover may require more moisture, as they are more susceptible to evaporation. Ponding or trapping of water in localized areas adjacent to the foundations can cause differential moisture levels in subsurface soils and, therefore, should not be allowed. Trees located within a distance of 20 feet of foundations would require more water in periods of extreme drought, and in some cases, a root injection system may be required to maintain moisture equilibrium. During extreme hot and dry periods, close observations should be carried out around foundations to ensure that adequate watering is being undertaken to prevent soil from separating or pulling back from the foundation. 5.12 Future Investigation The findings of this report indicate that the proposed grading is geotechnically feasible. Prior to construction, additional geotechnical investigation will be required to further evaluate metavolcanic rock and fill areas to provide additional subsurface information regarding oversized rock and excavation characteristics of metavolcanic rock. In addition, laboratory testing to assess soil corrosivity will need to be performed during a future site investigation. This information may then be utilized to provide additional construction level recommendations. -29- 042631-001 5.13 Construction Observation and Testing and Plan Review The geotechnical consultant should perform construction observation and testing during the fine, and post grading operations, future excavations and foundation or retaining wall construction at the site. Additionally, footing excavations should be observed and moisture determination tests of the slab subgrade soils should be performed by the geotechnical consultant prior to the pouring of concrete. Foundation ·design plans should also be reviewed by the geotechnical consultant prior to excavations. -30- • 042631-001 6.0 LIMITATIONS The conclusions and recommendations presented in this report are based in part upon data that were obtained from a limited number of observations, site visits, excavations, samples, and tests. Such information is by necessity incomplete. The nature of many sites is such that differing geotechnical or geological conditions can occur within small distances and under varying climatic conditions. Changes in subsurface conditions can and do occur over time: Therefore, the findings, conclusions, and recommendations presented in this report can be relied upon only if Leighton has the opportunity to observe the subsurface conditions during grading and construction of the project, in order to confirm that our preliminary findings are representative for the site. -31 - '' . FIGURES 0 2,000 4 000 Fee, Project: 042631-001 Eng/Geol: Scale: 1 • = 2.000 · Date: September, 201 Base Map ESRI Resov,ce Cenlet 2010 Themahc: Info Letghton Author Leighton Geomahcs 1mmurphy) SITE LOCATION MAP La Costa Town Center Carlsbad, California PLATE LEGEND -W:i A A' ~-----~ ! 368 I Af Afo Jsp APPROXIMATE LIMITS OF KEYWAY APPROXIMATE LOCATION OF RECOMMENDED BUILDING PAD OVEREXCAVATION DUE TO TRANSITION CONDITIONS AND METAVOLCANIC ROCK GEOLOGIC CROSS-SECTION APPROXIMATE GEOLOGIC CONTACT APPROXIMATE REMOVAL BOTTOM ELEVATION COMPACTED FILL (SCS&T, 2012) FROM PREVIOUS GRADING PRE -EXISTING FILL SANTIAGO PEAK VOLCANICS (CIRCLED WHERE BURIED) LIMIT OF PREVIOUS BUILDING PAD OVEREXCAVATION (SCS&T, 2012) AND PARKING LOT I ./ I , --=- ! / .... l j f, , , .... ...., ,-' , , \-j ,AJ\) • ; F. v._Y -------~------~ --------- f"'-J ;-:._L} , . ...,h !i I, )> (/) -0 :r: Leighton , '! . ! .:J " f I f ,, /' \ \, ___ _ '-I I \ . \ \ __ r, CONC , , ).{-l , , ' . ' ., {'"'(\ ' . ; ~,l ( Proj: 042631-001 Scale: 1 "=40' Dmftec! By: MMI Checked ~ I 1'r I 0 40 80 SCALE FEET Eng/Geol: WDO/MDJ Date: 09/2012 A 380 ........ I-w w L,_ ....... z 340 0 i== <( > w ....I w 300 Existing Grade -----Af -/ -- Afo -:- -----------------........._ -----------------~ Jsp --..-. __ Proposed Grade · Af -----_:.----Af Approximate Limit of Proposed Overexcavation due to metavolcanic rock Existing Grade Proposed Grade Af -------------------:....--- Jsp Jsp Jsp A' T Approximate Limit of Proposed Overexcavation due to metavolcanic rock 380 340 300 260__JL,._ ______________________________ ......;. ________ ......;. ____ _.;... ____ ;._ ________ .;.._ ___ --'-_____________ -'-----------------------------'-260 0 40 80 SCALE FEET --------------------------- LEGEND -APPROXIMATE GEOLOGIC CONTACT Af Afo Jsp COMPACTED FILL FROM PREVIOUS GRADING (SCS&T, 2012) PRE-EXISTING FILL SANTIAGO PEAK VOLCANICS (CIRCLED WHERE BURIED) -------------------------------- PLATE 2 Le1ghton CROSS-SECTION A-A" LA COSTA TOWN CENTER CARLSBAD, CALIFORNIA Proj: 042631-001 Eng/Geol: WDO/MDJ Scale: 1 "=40' Date: 09/2012 Cl rafted By: W'iM Checked By: P;\DRAFTING\O<l:.e31\001\0F_2012..(JS-CN'LATES1&2.DWG (OSJ...2<!-12 10;2S;55AMJ P'Cllted by; mmu<pl\y ------------------------------------------------ APPENDIX A REFERENCES Blake, 2000, EQFAUL T, Version 3.0. APPENDIX A REFERENCES 042631-001 Bryant, W.A., and Hart E.W., 2007, Special Publication 4~, Fault Rupture Hazard Zones in California, Alquist-Priolo Earthquake Fault Zoning Act with Index to Earthquake Fault Zone Maps, Interim Revision 2007. California Building Standards Commission (CBSC), 2010, California Building Code (CBC). Hart and Bryant, E.W., 2007, Fault-Rupture Hazard Zones in California, Alquist-Priolo Earthquake Fault Zoning with Index to Special Study Zones Maps: Department of Conservation, Division of Mines and Geology, Special Publication 42. Jennings, C.W., 1994, Fault Activity Map of California and Adjacent Areas; California Division of Mines and Geology, Geologic Data Map 6, Scale 1 :750,000. Kennedy, M.P., 1977, Geology of San Diego Metropolitan Area, California: California Division of Mines and Geology, Bulletin 200. Latitude 33 Planning and Engineering, 201 2, Preliminary Site Grading Plan, La Costa Town Center, Carlsbad, California, received September 2012. Lindvall, S.C., and Rockwell, T.K., 1995, Holocene Activity of the Rose Canyon Fault Zone in San Diego, California: Journal of Geophysical Research, V. 100, No. B12, p. 24, 124-24, 132. Southern California Soil & Testing, Inc., 2012, Update Geotechnical Investigation, La Costa Town Square, North Residential Development, Carlsbad California, dated January 3, 2012 Treiman, J.A., 1984, The Rose Canyon Fault Zone: A Review and Analysis, California Division of Mines and Geology, Funded by Federal Management Agency Cooperative Agreement EMF-83-K-0148. A-1 042631-001 APPENDIX A (Continued) ---, 1993, The Rose Canyon Fault Zone, Southern California: California Division of Mines and Geology, Open-File Report 93-2, 45p. A-2 APPENDIX B LABORATORY TESTING AND FIELD DENSITY TESTS BY OTHERS 042631-001 APPENDIX B Laboratory Testing Procedures and Test Results Moisture and Density Determination Tests: Moisture content and dry density determinations were performed on relatively undisturbed samples obtained from the test borings. The results of these tests are presented in the boring logs. When=~ applicable, only moisture content was determined from "undisturbed" or disturbed samples. 8-1 JOB NAME: La Costa Town Center JOB NUMBER: 0411014-4 IN-PLACE· DENSITY .TESTS'. TEST ELEVATION MOISTURE ORY DENSITY SOIL REL.COMP. NO. DATE LOCATION (feet,MSL) (percent)· (p.c.f.) TYPE (percent) GRADING 1 1116/04 See Plan 310.0 11.9 125.6 1C 95.9 2 1/16/04 See Plan 3120 10.7 130.2 1F 95.5 3 1/16/04 See Plan 314 0 122 127.4 10 96.1 4 1/16/04 See Plan 316 0 9.8 124.9 1F' 91 .6 5 1/16/04 See Plan 318 0 11. 7 128.4 1E 95.6 6 1/16/04 See Plan 320.0 11.3 130.0 2'/: · 93.5 7 1/16/04 See Plan 322.0 11.1 129.2 2E 94.2 8 1/19/04 See Plan 3240 13.2 128.8 2E 93.9 9 1/1 9/04 See Plan 3260 11 .8 126.7 2F 91.1 10 1/19/04 See Plan 328.0 12.7 127.2 2F 91.4 11 1/19/04 See Plan 330.0 14.1 125.8 1E 93.7 12 1/19/04 See Plan 332.0 14.6 130 6 1F 95.7 13 1/19/04 See Plan 334.0 14.0 131.4 2F 94.5 14 1/19/04 See Plan 336.0 13.8 127.7 2C 95.3 15 1/19/04 See Plan 338.0 15.1 128.3 2E 93.5 16 1/20/04 See Plan 340 .0 10.7 126.8 1E 94.4 17 1/20/04 See Plan 340.0 11.4 130.4 1F 95.6 18 1/20/04 See Plan 3420 11.7 125.9 10 94.9 19 1/20/04 See Plan 342.0 10.9 128.6 1F 94.3 20 1/28/04 See Plan 3580 9.7 123.1 2A 94.0 21 1/28/04 See Plan 361.0 10.4 125.2 28 94.5 22 1/28.'04 See Plan 3690 11.5 124.3 2B 93.8 23 1/29/04 See Plan 344.0 10.7 126.9 1E 945 24 1/29/04 See Plan 344.0 11.4 128.4 lF 94 1 25 1/29/04 See Plan 346.0 9.2 130 2 1F 95 5 26 1/29/04 See Plan 3460 87 125.6 1D 94.7 27 1/29/04 See Plan 348.0 11 .6 127.7 1E 95.1 28 1/29/04 See Plan 348 0 12 8 127.4 1E 94 9 29 1/29/04 See Plan 350.0 15 2 125.2 10 94 4 30 1129/04 See Plan 350.0 11 .1 130.0 1F 95.3 31 1/29/04 See Plan 352.0 10.6 126.8 1E 94.4 32 1/30/04 See Plan 352.0 9.7 125.4 1E 93.4 33 1/30/04 See Plan 354 .0 8.4 130.6 1F 95 7 34 1130104 See Plan 354.0 10.8 129.9 1F 95.2 35 1/30/04 See Plan 3560 11.2 127.4 1F 93.4 36 1130/04 See Plan 3560 10.4 126 6 1F 92.8 37 1/30/04 See Plan 358 0 96 131.2 1F 96.2 38 1/30104 See Plan 358 0 10.1 126.3 1F 92 6 39 215104 See Plan 351 0 10. 7 129 6 1F 95.0 40 215/04 See Plan 3530 11.5 130 1 1F 95 4 41 215/04 See Plan 3560 9.4 125.9 1D 94 9 42 2/5/04 See Plan 360.0 9.7 126.7 1E 94 3 43 2/5/04 See Plan 360.0 10.1 125.4 1E 93.4 44 2/5/04 See Plan 362.0 8.7 128.2 1F 94.0 45 215/04 See Plan 362.0 9 4 127 3 1F 93 3 46 2/12/04 See Flan 364 0 18.9 100.7 .., I 97.0 47 Z/121:14 See Flan 3640 22 1 100 4 7 96 7 48 Zi12/84 See Plan 3660 20 4 100.2 7 965 49 2,12/04 See Plan 3660 19 8 100.9 7 97 2 PLATE NO 3 JOB NAME: La Costa Town Center JOB NUMBER: 0411014-4 IN-PLACE DENSITY TESTS 'I TEST ELEVATION MOISTURE DRY DENSITY SOIL REL.COMP. NO. DATE LOCATION !feet,MSL) !eercent) !e,c.t.) TYPE !eercent) 50 2/13/04 See Plan 364.0 10.6 126.7 1E 94.3 51 2/13/04 See Plan 364.0 11 .1 130.2 1F 95.5 52 2/13/04 See Plan 366.0 9.6 128.4 1E 95.6 53 2/13/04 See Plan 366.0 9.2 131 2 1F 96.2 54 2/17/04 See Plan 368.0 17 9 109 4 3 _908 55 2/17/04 See Plan 370.0 18.1 110.1 3 91 .4 56 2/17/04 See Plan 372.0 16.9 109.2 3 90.6 57 2/17/04 See Plan 374.0 20.4 106.9 4 90.6 58 2/1 7/04 See Plan 376.0 19.7 107 3 4 90.9 59 2125/04 See Plan 378.0 15.9 107.9 4 91.4 60 2/25/04 See Plan 3780 16.8 106.8 4 90.5 61 2/25/04 See Plan 380.0 14.6 107.8 4 91 .4 62 2/25/04 See Plan 3800 13.8 109.1 4 92.5 63 2/25/04 See Plan 372 0 18.4 89.7 7 864 64 2/25/04 See Plan 371 0 19 6 94.8 7 91 .3 65 2125/04 RETEST OF 63 372 0 16.9 93.9 7 90.5 66 2/25/04 See Plan 371 0 19.2 95.2 7 91.7 67 2125/04 See Plan 374 0 18 7 99.6 7 960 68 2125/04 See Plan 368 0 16.8 108.2 4 91 7 69 2/25/04 See Plan 371 0 14.4 109.8 4 93.1 70 3/1/04 See Plan 374 0 18.9 97.7 7 94.1 71 3/1/04 See Plan 374.0 19.4 101.1 7 97.4 72 3/1/04 See Plan 373 0 20.1 95.8 7 92 3 73 3/1/04 See Plan 376 0 17.8 97 9 7 94 3 74 3/1/04 See Plan 378 0 16.9 92.1 7 88.7 75 3/1/04 RETEST OF 74 378.0 '9.4 94.6 7 91.1 75 311/04 See Plan 374 0 14.6 992 5 88.6 77 3/1/04 See Plan 374.0 15.9 104.6 5 93 4 78 3/1/04 RETEST OF 76 374 0 17 7 102.9 5 91.9 79 3/1/04 See Plan 3765 14.8 101 .6 5 90.7 BJ 3/1/04 See Plan 3760 16.7 100.9 5 90.1 81 3/2104 See Plan 378.5 17.4 101.5 5 90.6 82 3/2/04 See Plan 380 0 17.9 100.7 7 970 83 3/2/04 See Plan 376 0 20.6 102.4 5 91.4 84 3/2/04 See Plan 375.0 16.8 101.1 5 90.3 85 3/2/04 See Plan 378 0 19 4 99 4 5 88.8 86 3/2/04 RETEST OF 85 3780 18.5 100.9 5 90 1 87 312104 See Plan 377.0 20.2 101 .6 5 90 7 88 3/2/04 See Plan 380 0 15.9 102 7 5 91 7 89 3/3/04 See Plan 380 0 19.6 103.6 5 925 90 3/3/04 See Plan 379.0 18.8 101 9 5 91.0 91 313104 See ?Ian 379 0 20 4 102 7 s 91.7 92 3/3/04 See Plan 381.0 21.1 100.9 5 90 1 93 3/3/04 See Plan 381 0 16 9 104.2 5 93.0 94 3/3/04 See Plan 382.0 18 4 100 8 5 90 0 95 3/8/04 See Plan 372 0 18.6 102 9 5 91 9 96 3/12104 See Plan 3700 161 102.0 5 91 1 97 3/ l 2/04 See Plan 372 0 15 9 10 1.6 5 90 7 98 3/1 2/04 See Plan 374.0 17 2 104 7 5 93 5 99 3:· 2/04 See Plan 382 C FG 15 6 103 1 5 92 1 1,J(I 3;· 2104 See Pl,rn 381 C r :::; 14 7 102 0 5 91 1 PLATE NO 4 JOB NAME: La Costa Town Center JOB NUMBER: 0411014-4 . IN-PLACE DENSITY TESTS I TEST ELEVATION MOISTURE DRY DENSITY SOIL REL.COMP. NO. DATE LOCATION !feet,Msq !eercent} (e.c.q TYPE !eercent! 101 3/12/04 See Plan 381.0 FG 13.9 102.6 5 91.6 102 3115/04 See Plan 372.0 16.1 101.0 5 90.2 103 3/15/04 See Plan 363.0 14.9 108.1 4 91.6 104 3/15/04 See Plan 368.0 13.7 106.7 4 90.4 105 3/15/04 See Plan 354.0 16.1 106.9 4 90.6 106 3/15/04 See Plan 369.0 15.6 101 .B 5 90.9 107 3/15/04 See Plan 355.0 13.8 101.3 5 90.4 108 3/15/04 See Plan 371 0 17.2 107.3 4 90.9 109 3/15/04 See Plan 348.0 15.1 106.5 4 90.3 110 3/15/04 See Plan 365.0 19.6 108.3 4 91 .8 111 3/15/04 See Plan 372.0 13.1 103.6 5 92.5 112 3/15/04 See Plan 363.0 12.9 102.1 5 91 .2 113 3/15/04 See Plan 373.0 15.2 100.9 5 90.1 114 3/15/04 See Plan 356.0 16.7 101 .3 5 90.4 115 3/17/04 See Plan 380 0 FG 10.7 102.9 5 91.9 116 3/17/04 See Plan 380.0 FG 11.9 101.6 5 90.7 117 3/17/04 See Plan 380.0 FG 14.1 104.2 5 93.0 118 3/17/04 See Plan 380.0 FG 12.7 100.9 5 90.1 119 3/17/04 See Plan 379.0 FG 12.6 101.4 5 90.5 120 3/17/04 See Plan 378.0 FG 13.1 102.9 5 91 9 121 3/17/04 See Plan 378.0 FG 11.7 103.7 5 92.6 122 3/18/04 See Plan 379 0 FG 12.7 101.4 5 90.5 123 3/18/04 See Plan 379.0 FG 11 .1 102.7 5 91 7 124 3/18/04 See Plan 377.0 FG 10.9 103.2 5 92.1 125 3/18/04 See Plan 377.0 FG 13.7 101.5 5 90.6 126 3/18/04 See Plan 377.0 FG 9.9 101.7 5 90.8 127 3/29/04 See Plan 381.0 FG 12.7 104.1 5 92.9 128 3/29/04 See Plan 383.0 FG 10.8 102.7 5 91 .7 129 3/29/04 See Plan 383.0 FG 98 101 9 5 91 .0 130 3/29/04 See Plan 376.0 FG 13.1 103.9 5 92.8 131 3/29/04 See Plan 368.0 FG 12.7 101.6 5 90.7 132 3/29/04 See Plan 374.0 FG 11.4 100.9 5 90 1 133 3/29/04 See Plan 374.0 FG 12.1 106 1 5 94.7 FG = Finish Grade STORM DRAIN S01 1/26/04 Storm Drain "A" 332 0 10. 7 126.7 10 95 6 SD2 1/26/04 Storm Dram "A" 3360 11.3 124.9 1D 94 2 S03 1/26/04 Storm Drain "A"' 339.0 9.8 125.4 1E 93 4 SD4 2/2/04 Storm Dram '"A' 349 0 9.6 128 7 1F 94 4 sos 2/2/04 Storm Drain "A" 352 0 87 130.1 1F 95 4 S06 2r2.104 Storm Drain .. A" 355 0 9.9 126.4 1E 94.1 SD7 212/04 Storm Drain "A" 358 0 10 4 128.8 1F 94.4 SD8 2/9/04 Storm Drain ··A" 329.5 9.7 127.5 1F 93.5 SD9 219104 Storm Drain 'A" 332 0 10.4 130.8 lF 95.9 SCIO 219104 Storm Drain 'A'' 335.0 8.8 125 .1 l F 92 4 SC 11 2!25104 Storm Drain "C" 315.5 15 2 102 1 5 91 2 SDl2 2/25104 Storm Drain "C" 317.5 14.3 104 8 5 93 6 SD13 2/25/04 Storm Drain "C · 319 5 14 1 103 4 5 92 3 SD14 2/25104 Storm Drain "C' 321 5 13 6 103 8 5 92 7 PLATE NO 5 JOB NAME: La Costa Town Center JOB NUMBER: 0411014-4 IN-PLACE DENSITY TESTS I TEST ELEVATION MOISTURE DRY DENSITY SOIL REL.COMP. NO. DATE LOCATION !feet,MSq !Eercent! {E.c.q TYPE !eercent) S015 2/25/04 Storm Drain "C" 323.5 15 2 102.9 5 91.9 SDi6 3112/04 Storm Drain '"B" 296.0 12.7 108.4 4 91 .9 $0'7 3112/04 Storm Drain '"B" 298.0 9.4 106.7 4 90.4 so·a 3112/04 Storm Drain "B" 300.0 10.6 110.3 4 93.5 SDt<l 3/12/04 Storm Drain "B" 302 0 11.9 107.9 4 91 .4 S020 3/181C4 Storm Drain "B" 301 0 13.1 109.0 4 92.4 S021 3/181C4 Storm Drain "B" 303.0 11.0 108.4 4 91 .9 S022 3/19/04 Abandoned Storm Drain 380.0 8.0 121 .7 2 94.0 S023 3/19104 Abandoned Storm Drain 377.0 7.9 122.4 2 945 MAXIMUM DENSITY ANO OPTIMUM MOISTURE SUMMARY {ASTM 01557! Soil Maximum Optimum ~ Soil Description Oensitj'., pcf Moisture,% 1 Reddish Brown Silty Sand 126.2 8.9 1A Reddish Brown Silty Sand with 5% Rock 127.7 8.5 18 Reddish Brown Silty Sand with 10% Rock 129.3 8.1 1C Reddish Brown Silty Sand with 15% Rock 131.0 7.8 ~ 1D Reddish Brown Silty Sand with 20% Rock 132.6 7.4 1E Reddish Brown Silty Sand with 25% Rock 134.3 7.0 ff Reddish Brown Silty Sand with 30% Rock 136.4 6.6 ") ,_ Brown Silty Sand with rock 129.5 8.1 2A Brown Silty Sand with rock w ith 5% Rock 131.0 7.8 2B Brown Silty Sand with rock with 10% Rock 132.5 7.4 2C Bcown Silty Sand with rock with 15% Rock 134.0 7.1 20 Brown Silty Sand with rock with 20% Rock 135.6 6.7 2E Brown Silty Sand with rock with 25% Rock 137.2 64 2F Brown Silty Sand with rock with 30% Rock 139.1 6 .0 3 Light Brown Silty Sand 120.5 7.3 i;. 4 Light Tan to VVhite Silty Sand 118.0 12.0 5 Tan to Brown Silty Sand/Sandy Silt with Clay 112.0 11.0 6 Brown Silty Sand with Clay 121.8 9.5 7 Tan Clayey to Sandy Silt 103.8 19 0 EXPANSION SAMPLE EXPANSION EXPANSION TEST SAMPLE LOCATION INDEX POTENTIAL E: 1 South Bu1!d1ng 91 high E2 East Building 54 medium E3 South Building 84 medium E4 East Building 63 medium ?LATE NO 6 CD Floor Slab ® Filter Fabric between rock and sorl 0) Backcut Typical Retaining Wall Subdrain Detail Not to Scale -----_,.._ ------ Compacted · Fill 12·· min. Mrradrain 6000 or equivalent. 213 wall height © Waterproof back ol wall following architect's specifications ® 4• minimum perforated pipe, SDR35 or equivalent. holes down, 1 % fall lo outlet. t op of pipe below top of slab. encased in 3;4• c rush ed rock. Provide 3 cubic feet per lin e ar fool crushed rock min,murn. Crushed rock to be surrounded by filter fabric (Mirati 140N or equivalent). with s· minimum overlap. Provide solid outlet pipe at suit able location. LA COST A TOWN CENTER SC sTT SOUTHERN CALIFORNIA SOIL & TESTING, INC. BY: MF DATE· 04-20·04 JOB NUMBER. 0411014·4 PLATE NO. 7 APPENDIX C GENERAL EARTHWORK AND GRADING SPECIFICATIONS LEIGHTON AND ASSOCIATES, INC. General Earthwork and Grading Specifications 1.0 General 1.1 Intent 1.2 These General Earthwork and Grading Specifications are for the grading and earthwork shown on the approved grading plan(s) and/or indicated in the geotechnical report(s). These Specifications are a part of the recommendations contained in the geotechnical report(s). In case of conflict, the specific recommendations in the geotechnical report shall supersede these more general Specifications. Observations of the earthwork by the project Geotechnical Consultant during the course of grading may result in new or revised recommendations that could supersede these specifications or the recommendations in the geotechnical report(s). The Geotechnical Consultant of Record Prior to commencement of work, the owner shall employ the Geotechnical Consultant of Record (Geotechnical Consultant). The Geotechnical Consultants shall be responsible for reviewing the approved geotechnical report(s) and accepting the adequacy of the preliminary geotechnical findings, conclusions, and recommendations prior to the commencement of the grading. Prior to commencement of grading, the Geotechnical Consultant shall review the "work plan" prepared by the Earthwork Contractor (Contractor) and schedule sufficient personnel to perform the appropriate level of observation, mapping, and compaction testing. During the grading and earthwork operations, the Geotechnical Consultant shall observe, map, and document the subsurface exposures to verify the geotechnical design assumptions. If the observed conditions are found to be significantly djfferent than the interpreted assumptions during the design phase, the Geotechnical Consultant shall inform the owner, recommend appropriate changes in design to accommodate the observed conditions, and notify the review agency where required. Subsurface areas to be ·geotechnically observed, mapped, elevations recorded, and/or tested include natural ground after it has been cleared for receiving fill but before fill is placed, bottoms of all "remedial removal" areas, all key bottoms, and benches made on sloping ground to receive fill. The Geotechnical Consultant shall observe the moisture-conditioning and processing of the subgrade and fi ll materials and perform relative compaction testing of fill to determine the attained level of compaction. The Geotechnical Consultant shall provide the test results to the owner and the Contractor on a routine and frequent basis. -1- LEIGHTON AND ASSOCIATES, INC. General Earthwork and Grading Specifications 20 1.3 The Earthwork Contractor The Earthwork Contractor (Contractor) shall be qualified, experienced, and knowledgeable in earthwork logistics, preparation and processing of ground to receive fill, moisture-conditioning and processing of fill, and compacting fill. The Contractor shall review and accept the plans, geotecbnical report(s), and these Specifications prior to commencement of grading. The Contractor shall be solely responsible for performing the grading in accordance with the plans and specifications. The Contractor shall prepare and submit to the owner and the Geotechnical Consultant a work plan that indicates the sequence of earthwork grading, the number of "spreads" of work and the estimated quantities of daily earthwork contemplated for the site prior to commencemeot of grading. The Contractor shall inform the owner and the Geotechnical Consultant of changes in work schedules and updates to the work plan at least 24 hours in advance of such changes so that appropriate observations and tests can be planned and accomplished. The Contractor shall not assume that the Geotechnical Consultant is aware of all grading operations. The Contractor shall have the sole responsibility to provide adequate equipment and methods to accomplish the earthwork in accordance with the applicable grading codes and agency ordinances, these Specifications, and the recommendations in the approved geotechnical report(s) and grading plan(s). If, in the opinion of the Geotechnical Consultant, unsatisfactory conditions, such as unsuitable soil, improper moisture condition, inadequate compaction, insufficient buttress key size, adverse weather, etc., are resulting in a quality of work less than required in these specifications, the Geotechnical Consultant shall reject the work and may recommend to the owner that construction be stopped until the conditions are rectified. Preparation of Areas to be Filled 2.1 Clearing and Grubbing Vegetation, such as brush, grass, roots, and other deleterious material shall be sufficiently removed and properly disposed of in a method acceptable lo the owner, governing agencies, and the Geotechnical Consullant. The Geotechnical Consultant shall evaluate the extent of these removals depending on specific site conditions. Earth fill material shall not contain more than I percent of organic materials (by volume). No fill lift sha ll contain more than 5 percent of organic mailer. Nesting of the organic materials shall not be allowed. -2- LEIGHTON AND ASSOCIATES, INC. General Earthwork and Grading Specifications If potentially hazardous materials are encountered, the Contractor shall stop work in the affected area, and a hazardous material specialist shall be informed immediately for proper evaluation and handling of these materials prior to continuing to work in that area. As presently defined by the State of California, most refined petroleum products (gasoline, diesel fuel, motor oil, grease, coolant, etc.) have chemical constituents that are considered to be hazardous waste. As such, the indiscriminate dumping or spillage of these fluids onto the ground may constitute a misdemeanor, punishable by fines and/or imprisonment, and shall not be allowed. 2.2 Processing Existing ground that bas been declared satisfactory for support of fill by the Geotechnical Consultant shall be scarified to a minimum depth of 6 inches. Existing ground that is not satisfactory shall be overexcavated as specified in the following section. Scarification shall continue until soils are broken down and free of large clay lumps or clods and the working surface is reasonably uniform, flat, and free of uneven features that would inhibit uniform compaction. 2.3 Overexcavation 2.4 2.5 In addition to removals and overexcavations recommended in the approved geotechnical report(s) and the grading plan, soft, loose, dry, saturated, spongy, organic-rich, highly fractured or otherwise unsuitable ground shall be overexcavated to competent ground as evaluated by the Geotecbnical Consultant during grading. Benching Where fills are to be placed on ground with slopes steeper than 5: I (horizontal to vertical units), the ground shall be stepped or benched. Please see the Standard Details for a graphic illustration. The lowest bench or key shall be a minimum of 15 feet wide and at least 2 feet deep, into competent material as evaluated by the Geotechnical Consultant. Other benches shall be excavated a minimum height of 4 feet into competent material or as otherwise recommended by the Geotechnical Consultant. Fill placed on ground sloping flatter than 5: I shall also be benched or otherwise overexcavated to provide a flat subgrade for the fill. Evaluation/ Acceptance of Fil I Areas All areas to receive fill, including removal and processed areas, key bottoms, and benches, shall be observed, mapped, elevations recorded, and/or tested prior to being accepted by the Geotechnical Consultant as suitable to receive fill. The Contractor shall obtain a written acceptance from the Geotechnical Consultant -3- LEIGHTON AND ASSOCIATES, INC. General Earthwork and Grading Specifications prior to fill placement. A licensed surveyor shall provide the survey control for determining elevations of processed areas, keys, and benches. 3.0 Fill Material 4.0 3.1 3.2 3.3 General Material to be used as fill shall be essentially free of organic matter and other deleterious substances evaluated and accepted by the Geotechnical Consultant prior to placement. Soils of poor quality, such as those with unacceptable gradation, high expansion potential, or low strength shall be placed in areas acceptable to the Geolechnical Consultant or mixed with other soils to achieve satisfactory fill material. Oversize Oversize material defined as rock, or other irreducible material with a maximum dimension greater than 8 inches, shall not be buried or placed in fill unless location, materials, and placement methods are specifically accepted by the Geolechnical Consultant. Placement operations shall be such that nesting of oversized material does not occur and such that oversize material is completely surrounded by compacted or densified fill. Oversize material shall not be placed within IO vertical feet of finish grade or within 2 feet of future utilities or underground construction. Import If importing of fi ll material is required for grading, proposed import material shall meet the requirements of Section 3. I. The potential import source shall be given to the Geotechnical Consultant at least 48 hours (2 working days) before importing begins so that its suitability can be determined and appropriate tests performed. Fill Placement and Compaction 4.1 Fill Layers Approved fill material shall be placed in areas prepared to receive fill (per Section 3.0) in near-horizontal layers not exceeding 8 inches in loose thickness. The Geotechnical Consultant may accept thicker layers if testing indicates the grading procedures can adequately compact the thicker layers. Each layer shall be spread evenly and mixed thoroughly to attain relative unifonnity of material and moisture throughout. -4- LEIGHTON AND ASSOCIATES, INC. General Earthwork and Grading Specifications 4.2 Fill Moisture Conditioning Fill soils shall be watered, dried back, blended, and/or mixed, as necessary to attain a relatively uniform moisture content at or slightly over optimum. Maximum density and optimum soil moisture content tests shall be performed in accordance with the American Society of Testing and Materials (ASTM Test Method D 1557). 4.3 Compaction of Fill After each layer has been moisture-conditioned, mixed, and evenly spread, it shall be uniformly compacted to not less than 90 percent of maximum dry density (ASTM Test Method D 1557). Compaction equipment shall be adequately sized and be either specifically designed for soil compaction or of proven reliability to efficiently achieve the specified level of compaction with uniformity. 4.4 Compaction of Fill Slopes In addition to normal compaction procedures specified above, compaction of slopes shall be accomplished by backrolling of slopes with sheepsfoot rollers at increments of 3 to 4 feet in fill elevation, or by other methods producing satisfactory results acceptable to the Geotechnical Consultant. Upon completion of grading, relative compaction of the fill, out to the slope face, shall be at least 90 percent of maximum density per ASTM Test Method D1557. 4.5 Compaction Testing 4.6 Field-tests for moisture content and relative compaction of the fill soils shall be performed by the Geotechnical Consultant. Location and frequency of tests shall be at the Consultant's discretion based on field conditions encountered. Compaction test locations will not necessarily be selected on a random basis. Test locations shall be selected to verify adequacy of compaction levels in areas that are judged to be prone to inadequate compaction (such as close to slope faces and at the fill/bedrock benches). Frequency of Compaction Testing Tests shall be taken at intervals not exceeding 2 feet in vertical rise and/or 1,000 cubic yards of compacted fill soils embankment. In addition, as a guideline, at least one test shall be taken on slope faces for each 5,000 square feet of s lope face and/or each 10 feet of vertical height of slope. The Contractor shall assure that fill construction is such that the testing schedule can be accomplished by the Geotechnical Consultant. The Contractor shall stop or slow down the earthwork construction if these minimum standards are not met. -5- LEIGHTON AND ASSOCIATES, INC. General Earthwork and Grading Specifications 5.0 4.7 Compaction Test Locations The Geotechnical Consultant shall document the approximate elevation and horizontal coordinates of each test location. The Contractor shall coordinate with the project surveyor to assure that sufficient grade stakes are established so that the Geotechnical Consultant can determine the test locations with sufficient accuracy. At a minimum, two grade stakes within a horizontal distance of 100 feet and vertically less than 5 feet apart from potential test locations shall be provided. Subdrain Installation Subdrain systems shall be installed in accordance with the approved geotechnical report(s), the grading plan, and the Standard Details. The Geotechnical Consultant may recommend additional subdrains and/or changes in subdrain extent, location, grade, or material depending on conditions encountered during grading. All subdrains shall be surveyed by a land surveyor/civil engineer for line and grade after installation and prior to burial. Sufficient time should be allowed by the Contractor for these surveys. 6.0 Excavation Excavations, as well as over-excavation for remedial purposes, shall be evaluated by the Geotechnical Consultant during grading. Remedial removal depths shown on geotechnical plans are estimates only. The actual extent of removal shall be determined by the Geotechnical Consultant based on the field evaluation of exposed conditions during grading. Where fill-over-cut slopes are to be graded, the cut portion of the slope shall be made, evaluated, and accepted by the Geotechnical Consultant prior to placement of materials for constrnction of the fi ll portion of the slope, unless otherwise recommended by the Geotechnical Con~tltanl. 7.0 Trench Backfills 7.1 Safety The Contractor shall follow all OSHA and Cal/OSHA requirements for safety of trench excavations. · -6- LEIGHTON AND ASSOCIATES, INC. General Earthwork and Grading Specifications 7.2 Bedding and Backfill 7.3 All bedding and backfill of utility trenches shall be performed in accordance with the applicable provisions of Standard Specifications of Public Works Construction. Bedding material shall have a Sand Equivalent greater than 30 (SE>30). The bedding shall be placed to 1 foot over the top of the conduit and densified. Backfill shall be placed and densified to a minimum of 90 percent of relative compaction from I foot above the top of the conduit to the surface. The Geotechnical Consultant shall test the trench backfill for relative compaction. At least one test should be made for every 300 feet of trench and 2 feet of fill. Lift Thickness Lift thickness of trench backfill shall not exceed those allowed in the Standard Specifications of Public Works Construction unless the Contractor can demonstrate to the Geotechnical Consultant that the fill lift can be compacted to the minimum relative compaction by his alternative equipment and method. 7.4 Observation and Testing The densification of the bedding around the conduits shall be observed by the Geotechnical Consultant. -7- ALL SLOPE PROJECTED PLANE 1: 1 (HORIZONTAL: VERTICAL) MAXIMUM FROM TOE OF SLOPE TO APPROVED GROUND EXISTING GROUND SURFACE ALL -OVER-CUT SLOPE ----:;..;:::t::::::=::===:==:O::::::::::i _., ,,....---. ! 1 s FEET MIN. I _., _.,/2 LOWEST -2 FEET BENCH (KEY) REMOVE UNSUITABLE MATERIAL -~., "\ ~~~-KEY ~TH CUT FACE SHALL BE CONSTRUCTED PRIOR TO , ,,.. FILL PLACEMENT TO ALLOW VIEWING / / OF GEOLOGIC CONDITIONS , / CUT-OVER-FLL SLOPE PROJECTED PLANE 1 TO 1 MAXIMUM FROM TOE OF SLOPE TO APPROVED GROUND OVERBUILD AND•---'"" TRIM BACK DESIGN SLOPE---..= KEYING AND BENCHING / / REMOVE UNSUITABLE MATERIAL UT FACE SHALL BE CONSTRUCTED PRIOR TO FILL PLACEMENT BENCHING SHALL BE DONE WHEN SLOPE'S ANGLE IS EQUAL TO OR GREATER THAN 5: 1. MINIMUM BENCH HEIGHT SHALL BE 4 FEET AND MINIMUM FILL WIDTH SHALL BE 9 FEET. GENERAL EARTHWORK AND GRADING SPECIFICATIONS STANDARD DETAIL A FINISH GRADE -------------------------~---------------------.. .. OVERSIZE WINDROW • OVERSIZE ROCK IS LARGER THAN 8 INCHES IN LARGEST DIMENSION. • EXCAVATE A TRENCH IN THE COMPACTED FILL DEEP ENOUGH TO BURY ALL THE ROCK. • BACKFILL WITH GRANULAR SOIL JETTED OR FLOODED IN PLACE TO FILL ALL THE VOIDS. • 00 NOT BURY ROCK WITHIN 10 FEET OF FINISH GRADE. • WINDROW OF BURIED ROCK SHALL BE PARALLEL TO THE FINISHED SLOPE. GRANULAR MATERIAL TO BE OENSIFIEO IN PLACE BY FLOODING OR JETTING. DETAIL --------JETTED OR FLOODED ----- GRANULAR MA T[RIAL TYPICAL PROFILE ALONG WINDROW OVERSIZE ROCK DISPOSAL GENERAL EARTHWORK AND GRADING SPECIFICATIONS STANDARD DETAIL B BENCHING SUBDRAIN DETAIL -....... -.. SUBDRAIN TRENCH SEE DETAIL BELOW FILTER f" ABRIC REMOVE UNSUITABLE MATERIAL (MIRAFI 140N OR APPROVED EQUIVALENT)• COLLECTOR PIPE SHALL BE MINIMUM 6" DIAMETER SCHEDULE 40 PVC PERFORATED PIPE SEE STANDARD DETAIL D FOR PIPE SPECIFICATIONS DESIGN FINISH GRADE ... : :·:·:::::=:=:=:=:=:=:=: 10' MIN. FILTER FABRIC . ·=:=:I~t1@~ittif tf !# ~t[f :.~ k~~l~L~~~) OR APPROVED :=:::::=:::::::::-···, .. '•. • : • · . ' : • • · . --CALTRANS CLASS 2 PERMEABLE ••••.••••••••••· • • • .• '• '·. ; _-:· . • . •. •. : • •• OR #2 ROCK (9rrJ/FT} WRAPPED I • • • • • IN FILTER FABRIC I-20' MIN. ~• MIN. i----PERFORA TED NONPERFORA TED 6. 0 MIN 6" 0 MIN. PIPE DETAIL OF CANYON SUBDRAIN OUTLET CANYON SUBDRAINS GENERAL EARTHWORK AND GRADING SPECIFICATIONS STANDARD DETAIL C OUTLET PIPES 4" 0 NONPERFORATED PIPE, 100' MAX. 0 .C. HORIZONTALLY, JO' MAX O.C. VERTICALLY 1 2" MIN. OVERLAP FROM THE TOP HOG RING TIED EVERY 6 FEET CAL TRANS CLASS II PERMEABLE OR #2 ROCK (J FrJ/FT) WRAPPED IN FILTER FABRIC PROVIDE POSITIVE SEAL AT THE JOINT 15' MIN. TRENCH LOWEST SUBDRAIN SHOULD BE SITUATED AS LOW AS POSSIBLE TO ALLOW SUITABLE OUTLET T-CONNECTION FOR COLLECTOR PIPE TO OUTLET PIPE FILTER FABRIC ENVELOP( (MIR AFI 140 OR APPROVED EQUIVALENT) SUBDRAIN TRENCH DETAIL SUBORAIN INSTALLATION -subdroin Collector pipe sholl be installed with perforation down or. unless o therwise designated by the geotechnicol consultant Outlet pipes sholl be non-perloroted pipe. The subdroin pipe sholl hove ot leost 8 perforations uniformly spoced per foot Perforation shell be 1/4" to 1/2" if drill holes ore used All subdroin p ipes sholl hove o grodienl of ot leost 2% towards the outlet. SUBORAIN PIPE -Subdro,n pipe shall be ASHA D2751, SOR 23 5 or ASHA 01527, Schedule 40, or ASHA 03034. SOR 23.5. Schedule 40 Folyvinyt Chloride Plastic {PVC) pipe. All outlet pipe sholl be pieced ,n o trench no wider thon twice the subdroin pipe. BUTTRESS OR REPLACEMENT FILL SUBDRAINS GENERAL EARTHWORK AND GRADING SPECIFI CATIONS STANDARD DETAIL D CUT-FILL TRANSITION LOT OVEREXCAVA TION REMOVE UNSUITABLE ::;ROUND \_,_ -- - TRANSITION LOT FILLS ----- OV[R[XCAVATE ANO RECOMPACl -- GENERAL EARTHWORK AND GRADING SPECIFICATIONS STANDARD DETAIL E ---- 5' MIN RETAINING WALL WALL WATERPROOFING ~ PER ARCHITECT'S SPECIFICATIONS FINISH GRADE ·---------------------------------·-·=:=:=:::::::::~:~:~:?~~~:~??:1:~:~tt??tt! SOIL BACKFILL, COMPACTED TO 90 PERCENT RELATIVE COMPACTION BASED ON ASTM 01557 __________ ------------------------·------:-:•:-:-.--·=-=-~--t/~)///;~ ~r=-~-~~}tt=·=-~-- = = = = = =: = = = = = = ::::::::::~ r= -=---·.·--.-_::::- 1 I-::::jl--·-·-·.--·.-.-.-.-. I' J~~~~-p ·, t{tf FILTER FABRIC ENVELOPE • o . .·.-.·-·.-· (MIRAFI 140N OR APPROVED I° 0 o O • 0 1 \~/· EQUIVALENT) .. • • 0 0 :=:=:=:=: 10 r :IN .• 1 y-v◄-TO 1-1Ir CLEAN GRAVEL l•o : Si tt....--◄• (MIN.) DIAMETER PERFORATED ~ o 1-:y--PVC PIPE (SCHEDULE 40 OR I • o0 • :::::=::: EQUIVALENT) WITH PERFORATIONS 0 -:-:-:-:-ORIENTED DOWN AS DEPICTED I I:=:=:=:=: MINIMUM 1 PERCENT GRADIENT ::::::::: TO SUIT ABLE OUTLET l!:L=--===· 3~-:-~:·:c:.•=·--3· MIN. WALL FOOTING -- il!El11111.--:;im, COMPETENT BEDROCK OR MATERIAL AS EVALUATED BY THE GEOTECHNICAL CONSUL TANT NOTE: UPON REVIEW BY THE GEOTECHNICAL CONSUL TANT. COMPOSITE DRAINAGE PRODUCTS SUCH AS MIRADRAIN OR J-DRAIN MAY BE USED AS AN ALTERNATIVE TO GRAVEL OR CLASS 2 PERMEABLE MATERIAL. INSTALLATION SHOULD BE PERFORMED IN ACCORDANCE WITH MANUFACTURER'S SPECIFICATIONS RETAINING WALL DRAINAGE GENERAL EARTHWORK AND GRADING SPECIFICATIONS STANDARD DETAIL F FILTER FABRIC ACTIVE ZONE ---~,l.::::::::::::: ,,---,,--- !-it[ REINFORCED RETAINED / ,._ _ __,f :~~-"{_i ZONE ZONE / ----•~~---------------I ---~.,(-::_-::::_-:::: ,,,,,' ----------r'-----f.}i~)(;;,,.,. • .,c / ••.:· .. :::._ --------------~ ..... ,....,-!-,...,..,.,.,....,~t.:•~::{ t§j ~ GRAVEL_-::--:---c~~...::.~:..e...tJ \ DRAINAGE FILL ----WALL SUBDRAIN MIN 6" BELOW WALL REAR SUBDRAIN: BACKDRAIN TO 70%OF WALL HEIGHT MIN 12" BEHIND UNITS 4" (MIN) DIAMETER PERFORATED PVC PIPE I FOUNDATION SOILS! (SCHEDULE 40 OR EQUIVALENT) WITH PERFORATIONS DOWN. SURROUNDED BY NOTES: 1) MATERIAL GRADATION AND PLASTICITY REINFORCED ZONE· SIEVE SIZE 1 INCH NO.4 NO. 40 NO. 200 %PASSING 100 20-100 ~o 0-35 FOR WALL HEIGHT < 10 FEET. PLASTICITY INDEX < 20 FOR WALL HEIGHT 10 TO 20 FEET. PLASTICITY INDEX< 10 FOR TIERED WALLS. USE COMBINED WALL HEIGHTS 1 CU. FT/FT OF 3/4" GRAVEL WRAPPED IN FILTER FABRIC (MIRAFI 140N OR EQUIVALENT) OUTLET SUBDRAINS EVERY 1Cl0 FEET. OR CLOSER. BY TIGHTLINE TO SUITABLE PROTECTED OUTLET GRAVEi DRAINAGE EILL· SIEVE SIZE 1 INCH 3/4 INCH NO.4 NO.40 NO. 200 %PASSING 100 75-100 0-00 0-50 0-5 WALL DESIGNER TO REQUEST SITE-SPECIFIC CRITERIA FOR WALL HEIGHT> 20 FEET 2) CONTRACTOR TO USE SOILS WITHIN THE RETAINED ANO REINFORCED ZONES THAT MEET THE STRENGTH REQUIREMENTS OF WALL DESIGN 3) GEOGRID REINFORCEMENT TO BE DESIGNED BY WALL DESIGNER CONSIDERING INTERNAL. EXTERNAL. ANO COMPOUND STABILITY. 3) GEOGRID TO BE PRETENSIONED DURING INSTALLATION. 4) IMPROVEMENTS WITHIN THE ACTIVE ZONE ARE SUSCEPTIBLE TO POST-CONSTRUCTION SETTLEMENT ANGLE Cl 45+¢/2. WHERE ¢> IS THE FRICTION ANGLE OF THE MATERIAL IN THE RETAINED ZONE. 5) BACKDRAIN SHOULD CONSIST OF J-DRAIN 302 (OR EQUIVALENT) OR 6-INCH THICK DRAINAGE FILL WRAPPED IN FILTER FABRIC. PERCENT COVERAGE OF BACKDRAIN TO BE PER GEOTECHNICAL REVIEW. SEGMENTAL RETAINING WALLS GENERAL EARTHWORK AND GRADING SPECIFICATIONS STANDARD DETAIL G