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HomeMy WebLinkAboutCT 2016-0002; TOWN HOUSE; LIMITED GEOTECHINICAL INVESTIGATION PROPOSED RAILYARD LOFTS RESIDENTIAL DEVELOPMENT; 2013-03-21^ \ EAST COUNTY SOIL CONSULTATION AND ENGINEERING, INC. 10925 HARTLEY ROAD, SUITE "I" SANTEE, CALIFORNIA 92071 (619) 258-7901 Fax 258-7902 Mark Benjamin March 21,2013 Archipelago Development Project No 13-1106D5 P 0 Box 7050 Rancho Santa Fe, California 92067 Subject Limited Geotechnical Investigation Proposed Railyard Lofts Residential Development 2685 State Street Carlsbad, Cahforma 92008 Dear Mr Benjamm In accordance with your request, we have performed a limited geotechmcal mvestigation at the subject site to discuss the geotechmcal aspects of the project and provide recommendations for the proposed development Our investigation has found that the proposed building pad is pnmanly underlam by topsoil, undocumented fill and alluvium to a depth of approximately 20 feet below existing grade These soils were underlam by dense sandstone of the Santiago Formation to the explored depth of 25 feet It is our opmion that the development of the proposed residential project is geotechmcally feasible provided the recommendations herem are implemented m the design and construction Should you have any questions with regard to the contents of this report, please do not hesitate to contact our office Respectfully submitted. Mamadou Sahou Diallo, P E RGB 54071, GE 2704 MSD\md ARCHIPELAGO DEVELOPMENT/ KAILYARD LOFTS PROJECT NO 13-1I06D5 TABLE OF CONTENTS INTRODUCTION 3 SCOPE OF SERVICES 3 SITE DESCRIPTION AND PROPOSED CONSTRUCTION .. 3 FIELD INVESTIGATION AND LABORATORY TESTING 4 GEOLOGY 4 Geologic Setting 4 Site Stratigraphy 4 SEISMICITY 5 Regional Seisrnicity 5 Seismic Analysis 5 2010 CBC Seismic Design Criteria 6 Geologic Hazard Assessment 6 GEOTECHNICAL EVALUATION 7 Compressible Soils 7 Expansive Soils 7 Groundwatei 7 CONCLUSIONS AND RECOMMENDATIONS 8 GRADING AND EARTHWORK 8 Clearing and Grubbing 8 Structural Improvement of Soils 8 Transitions Between Cut and Fill 9 Method and Cnteria of Compaction 9 Erosion Control 9 Standard Grading Guidelines 9 FOUNDATIONS AND SLABS 10 SETTLEMENT 10 PRESATURATION OF SLAB SUBGRADE 10 TEMPORARY SLOPES 1 TRENCH BACKFILL DRAINAGE 1 FOUNDATION PLAN REVIEW 1 LIMITATIONS OF INVESTIGATION ADDITIONAL SERVICES 12 PLATES Plate 1 - Location of Exploratory Boreholes Plate 2 - Summary Sheet (Exploration Borehole Logs) Plate 3 - uses Soil Classification Chart PAGE L-1, LABORATORY TEST RESULTS 16 REFERENCES 17 ARCHIPELAGO DEVELOPMENT/ RAIL YARD LOFTS PROJECT NO 13-1106D5 INTRODUCTION This IS to present the findings and conclusions of a limited geotechnical investigation for the proposed construction of a 3-story, residential building to be located at 2685 State Street, m the City of Carlsbad, California The objectives of the investigation were to evaluate the existing soils conditions and provide recommendations for the proposed development SCOPE OF SERVICES The followmg services were provided during this mvestigation O Site reconnaissance and review of published geologic, seismological and geotechnical reports and maps pertment to the project area O Subsurface exploration consistmg of five (5) boieholes within the limits of the proposed area of development The boreholes were logged by our Staff Geologist O Collection of representative soil samples at selected depths The obtained samples were sealed in moisture-resistant containers and tiansported to the laboratory for subsequent analysis O Laboiatory testing of samples representative of the types of soils encountered dunng the field investigation O Geologic and engineenng analysis of the field and laboratory data, which provided the basis for our conclusions and recommendations O Production of this report, which summanzes the results of the above analysis and presents our fmdmgs and recommendations for the proposed development SITE DESCRIPTION AND PROPOSED CONSTRUCTION The subject site is a rectangular-shaped, multi-piupose lot located on the west side of State Street, in the City of Carlsbad, California The vacant property encompasses an area of approximately 6,585 square feet It is presently used as a storage yard The site is relatively level with general drainage to the west Vegetation consisted of grass Site boundanes include State Street to the east, an alley to the west and eommercial developments to the lemaining directions The preliminary site plan prepared by PASCO LARET SUITER and Associates of Solana Beach, California indicates that the proposed construction will include a 4-umt residential complex It is our understanding that the structure will be three-story, wood-framed and founded on contmuous and spread footings with slab-on-grade floors Associated improvements \vill mclude a dnveway, landscapmg and other appurtenances ARCHIPELAGO DEVELOPMENT/ KAILYARD LOFTS PROJECT NO I3-I106D5 FIELD INVESTIGATION AND LABORATORY TESTING From February 26 to March 19, 2013. five (5) boreholes were dulled to a maximum depth of approximately 25 feet below existing grade with a hand auger and a dnil ng The approximate locations of the boreholes are shown on the attached Plate No 1, entitled "Location of Exploratory Boreholes" A contmuous log of the soils encountered was recorded at the time of excavation and IS shown on Plate No 2 entitled "Summary Sheet" The soils were visually and texturally classified according to the filed identification procedures set forth on Plate No 3 entitled "USCS Soil Classification" Following the field exploration, laboratory testing was performed to evaluate the pertinent engineenng pioperties of the foundation matenals The laboratory-testing program included moisture and density, particle size analysis, Atterbeig limits and expansion index tests These tests were performed in general accordance with ASTM standards and other accepted methods Page L-1 and Plate No 2 provide a summary of the laboratory test results GEOLOGY Geologic Setting The subject site is located withm the southern portion of what is known as the Peninsular Ranges Geomorphic Province of California The geologic map pertaming to the area (reference No 6) indicates that the site is underlain by terrace deposits (Qti) However, the following strata were encountered Site Stratigraphy The subsurface descnptions provided are mterpreted from conditions exposed during the field investigation and/or inferred fix)m the geologic literature Detailed descriptions of the subsurface matenals encountered dunng the field investigation are presented on the exploration logs provided on Plate No 2 The followmg paragraphs provide general descnptions of the encountered soil types Topsoil Topsoil is the surficial soil matenal that mantles the ground, usually containmg roots and other orgamc matenals, which supports vegetation Topsoil observed in the boreholes was approximately 6 to 18 mches thick It consisted of dark brown, silty sand that was moist, loose and porous in consistency with some orgamcs (roots and rootlets) Undocumented Fill (Ouf) Undocumented fill soils were encountered m most of the boreholes with a thickness of approximately 1 to 2 feet They generally consisted of reddish brown, silty sand that was moist and medium dense m consistency In Boreholes 1 and 2, the fill was overlam by a layer of gravel, approximately 6-mch thick ARCHIPELAGO DEVELOP'vfENT/ RAILYARD LOFTS PROJECT NO 13-110605 Alluvixim (Qal) The topsoil and undocumented fill were underlam by alluvium to a depth of approximately 20 feet The top 4 feet of the alluvium consisted of a layer of sandy clay/ clayey sand that was very moist to wet and medium stiff m consistency Dense sand was found below the clay layer Groundwater was encountered at a depth of approximately 9 feet in the sand and some cavmg was observed Santiago Formation (Tsa) Bedrock matenals associated with the Santiago Formation were encountered below the alluvium They generally consisted of light-colored sandstone that was very dense in consistency SEISMICITY Regional Seismicitv Generally, Seismicity within California can be attributed to the regional tectomc movement taking place along the San Andreas Fault Zone, which includes the San Andreas Fault and most parallel and subparallel faults within the state The portion of southern California where the subject site is located is considered seismically active Seismic hazards are attnbuted to groundshakmg from earthquake events along nearby or more distant Quaternary faults The primary factors m evaluating the effect an earthquake has on a site are the magnitude of the event, the distance from the epicenter to the site and the near surface soil profile Accordmg to the Fault-Rupture Hazard Zones Act of 1994 (revised Alquist-Pnolo Special Studies Zones Act), quaternary faults have been classified as •active' faults, which show apparent surface lupture dunng the last 11,000 years (i e , Holocene time) -Potentially-active" faults are those faults with evidence of displacing Quaternary sediments between 11,000 to 16,000 years old Seismic Analysis Based on our evaluation, the closest known "active" fault is the Rose Canyon Fault located approximately 7 5 kilometeis (4 7 miles) to the west The Rose Canyon Fault is the design fault of the project due to the predicted credible fault magnitude and ground acceleration The Seismicity of the site was evaluated utilizing determimstic methods (Eqseach/ Eqfault ver 3 0, Blake, 2008) for active Quaternary faults within the regional vicimty The site may be subjected to a Maximum Probable Earthquake of 6 9 Magnitude along the Rose Canyon fault, with a corresponding Peak Ground Acceleration of 0 34g The maximum Probable Earthquake is defined as the maximum earthquake that is considered likely to occur within a 100-year time period The effective ground acceleration at the site is associated with the part of significant ground mouon, which contains lepetitive strong-energy shaking, and which may produce structural deformation As such, the effective or ' free field" ground acceleration is referred to as the Repeatable High Ground Acceleration (RHGA) It has been determined by Ploessel and Slosson (1974) that the RHGA is approximately equal to 65 percent of the Peak Ground Acceleration for ARCHIPELAGO DEVELOPMENT/ RAIL YARD LOFTS PROJECT NO 13-1106D5 earthquakes occurring within 20 miles ot a site RHGA at the site is 0 22g 201Q CBC Seismic Design Criteria Based on the above, the calculated Credible A review of the active fault maps pertaimng to the site mdicates the existence of the Rose Canyon Fault Zone approximately 7 5 km to the west Ground shaking from this fault or one of the major active faults m the region is the most likely happenmg to affect the site With respect to this hazard, the site is comparable to others m the general area The proposed residential structure should be designed m accordance with seismic design requirements of the 2010 Califonua Building Code or the Structural Engineers Association of Cahforma usmg the following seismic design parameters PARAMETER VALUE 2010 CBC REFERENCE Site Class D Table 1613 5 2 Mapped Spectral Acceleration For Short Periods, S, 1 325 Figure 1613 5(3) Mapped Spectral Acceleration For a 1-Second Period, S| 0 498 Figure 1613 5(4) Site Coefficient, Fj 1 00 Table 1613 5 3(1) Site Coefficient, Fy 1 502 Table 1613 5 3(2) Geologic Hazard Assessment Ground Rupture Ground rupture due to active faulting is not considered likely due to the absence of known fault traces withm the vicimty of the project, however, this possibility cannot be completely ruled out The unlikely hazard of ground rupture should not preclude consideration of "flexible" design for on-site ubhty Imes and connections Liquefaction Liquefaction involves the substantial loss of shear strength m saturated soils, usually sandy soils with a loose consistency when subjected to earthquake shaking Based on the consistency of the underlying alluvium and Santiago Formation, it is our opinion that the potential for hquefaction is low Landsliding There is no indication that landslides or unstable slope conditions exist on or adjacent to the project site. There are no obvious geologic hazards related to landsliding to the proposed development or adjacent properties ARCHIPELAGO DEVELOPMENT/ RAILYARD LOFTS PROJECT NO 13-110605 Tsunamis and Seiches The site is not subject to mundation by tsunamis due to its elevation The site is also not subject to seiches (waves m confined bodies of water) GEOTECHNICAL EVALUATION Based on our mvestigation and evaluation of the collected mformation, we conclude that the proposed construction is feasible fiom a geotechmcal standpoint provided the recommendations provided herein will be properly implemented dunng structural development Tlie major factors affecting the proposed development are the existence of undocumented fill and highly expansive clayey soils at shallow depths A discussion of constraints and mibgative measures are as follows Compressible Soils Our field observations and testmg indicate low compressibility within the dense alluvium and sandstone of the Santiago Formation, which underlie the site However, loose topsoil and undocumented fill were encountered to a depth of approximately 3 feet below existmg grades These soils are compressible Also, the top 4 feet of the alluvium is highly expansive Due to the potential for soil compression upon loadmg, remedial and select grading of these near surface soils, including ovei excavation and recompaction will be required Following implementation of the earthwork recommendations presented herein, the potential for soil compression resulting from the new development has been estimated to be low The low-settlement assessment assumes a well-planned and maintained site drainage system Recommendations regarding mitigation by earthwork construction are presented m the Grading and Earthwork recommendations section of this report Expansive Soils Expansion index tests were performed on select samples of the fill and alluvium (clay part) to determine volumetnc change characteristics with change m moisture content Expansion indexes of 4 and 123 were obtained respectively which indicates a low and very high expansion potential for the subgrade soils Groundwater Perched groundwater was encountered at a depth of approximately 9 feet below existmg grade However, we do not exjject groundwater to affect the proposed construction Recommendations to prevent or mitigate the effects of poor surface dramage are presented m the Drainage section of this report ARCHIPELAGO DEVELOPMENT/ RAILYARD LOFTS PROJECT NO 13-110605 CONCLUSIONS AND RECOMMENDATIONS The following conclusions and recommendations are based upon the analysis ol the data and mfoimation obtained fiom our soil mvestigation This includes site reconnaissance, field investigation, laboratory testmg and our general knowledge of the soils native to the site The site is suitable for the proposed residential development provided the recommendations set forth are implemented dunng construction GRADING AND EARTHWORK Based upon the proposed construction and the information obtamed dunng the field investigation, we anticipate that the proposed stiuctuie will be founded on continuous and/ or spread footings, which are supported by properly compacted fill The following gradmg and earthwork recommendations are based upon the limited geotechnical investigation performed, and should be venfied dunng construction by our field representative Cleanng and Grubbing All areas to be graded or to receive fill and/or structures should be cleared of vegetation Vegetation and the debns from the cleanng operation should be properly disposed of off-site The area should be thoroughly inspected for any possible buned objects, which need to be rerouted or removed pnor to the inception of, or dunng gradmg All holes, trenches or pockets left by the removal of these objects should be properly backfilled with compacted fill matenals as recommended in the Method and Cntena of Compaction secton of this report Structural Improvement of Soils Information obtamed fkim our field and laboratory analysis indicates that loose topsoil and undocumented fill cover the building pad to a depth of approximately 3 feet below existng grade In addition, a 4-foot layer of highly expansive clay was underlying these soils These surficial soils are susceptible to settlement upon loading Based upon the sod charactenstics, we recommend the following. * All topsoil, undocumented fill and clay layer should be completely removed fixDm areas, which are planned to receive compacted fills and/or structural improvements The bottom of the removal area should expose competent matenals as approved by ECSC&E geotechmcal representative Pnor to the placement of new fill, the bottom of the removal area should be scanfied a minimum depth of 6 inches, moisture-conditioned withm 2 percent above the optunum moisture content, and then recompacted to at least 90 percent relative compaction (ASTM D1557 test method) The anticipated depth of removal is approximately 6 feet * Soils utilized as fill should be moisture-conditioned and recompacted m conformance with the followmg Method and Cntena of Compaction section of this report The actual depth and extent of any overexcavation and recompaction should be evaluated m the field by a lepresentative of ECSC&E ARCHIPELAGO DEVELOPMENT/ RAILYARD LOFTS PROJECT NO 13-1106D5 * An alternative to the overexcavation and recompaction of the building pad is to support the proposed structure on caissons and grade beams Design parameters may be provided upon request Transitions Between Cut and Fill The proposed structure is anticipated to be founded in properly compacted fill Cut to fill transitions below the proposed structure should be eliminated during the earthwork construction as required m the previous secton Method and Criteria of Compaction Compacted fills should consist of approved soil material, free of trash debns, roots, vegetation or other deleteiious materials. Fill soils should be compacted by suitable compaction equipment m umform loose lifts of 6 to 8 mches Unless otherwise specified, all soils subjected to recompaction should be moisture-conditioned withm 2 percent over the optimum moisture content and compacted to at least 90 percent relative compaction per ASTM test method D1557 The on-site soils with the exception of the clay layer, after being processed to delete the aforementioned deletenous materials, may be used for recompaction purposes The clay layer which is highly expansive should not be used as fill It should be hauled off-site and replaced with granular, non-expansive soils that should be evaluated and approved by ECSCE pnor to delivery to the site Erosion Control Due to the granular characteristics of the on-site soils, areas of recent gradmg or exposed ground may be subject to erosion Dunng construction, surface water should be controlled via berms, gravel/ sandbags, silt fences, straw wattles, siltation basins, positive surface grades or other method to avoid damage to the fmish work or adjoming properties All site entrances and exits must have coarse gravel or steel shaker plates to minimize offsite sediment tracking Best Management Practices (BMPs) must be used to protect storm drains and minimize pollution The contractor should take measures to prevent erosion of graded areas until such time as permanent drainage and erosion control measures have been installed After completion of gradmg, all excavated surfaces should exhibit positive drainage and eliminate areas where water might pond Standard Gradmg Guidehnes Gradmg and earthwork should be conducted in accordance with the standard-of-practice methods for this local, the guidelmes of the current edition of the Uniform Buildmg Code, and the requirements of the junsd'ictional agency Where the information provided m the geotechmcal report differs fiem the Standard Giadmg Gmdelmes, the requirements outlined m the report shall govern ARCHIPELAGO DEVELOPMENT/ KAILYARD LOFTS PROJECT NO I3-1106D5 FOUNDATIONS AND SLABS a Continuous and spread footings are suitable for use and should extend to a minimum depth of 24 inches below the lowest adjacent grade for the proposed three-story structure into the properly compacted fill soils Continuous footings should be at least 18 inches in width and reinforced with a mmimum of four #4 steel bars, two bars placed near the top of the footmgs and the other two bars placed near the bottom of the footmgs Isolated or spread footings should have a mmimum width of 24 inches Their reinforcement should consist of a minimum of #4 bars spaced 12 mches on center (each way) and placed horizontally near the bottom The rmmmum reinforcement recommended is based on soil charactenstics and is not mtended to supercede the structural engmeei requirements b. Intenor floor slabs should be a minimum 5-inch thick Reinforcement should consist of #3 bars placed at 16 inches on center each way within the middle third of the slabs by supporting the steel on chairs or concrete blocks "dobies" The slabs should be underlain by 2 inches of clean sand over a 10-mil visqueen moisture barrier and a capillary break at least 2 inches thick, consisting of coarse sand, gravel or crushed rock not exceeding 3/4 inch in size with no more than 5 percent passing the #200 sieve The effect of concrete shnnkage will result m cracks m virtually all-concrete slabs To leduce the extent of shnnkage, the concrete should be placed at a maximum of 4-inch slump The minimum steel recommended is not mtended to prevent shnnkage cracks c. An allowable soil beanng value of 2,000 pounds per square foot may be used for the design of continuous and spread footings at least 12 inches wide and founded a mimmum of 12 inches into properly compacted fill soils as set forth in the 2010 Califorma Building Code, Table 1806 2 This value may be increased by 400 psf for each additional foot of depth or width to a maximum value of 4,000 lb/ft2 d. Lateral resistance to honzontal movement may be provided by the soil passive pressure and the fnction of concrete to soil An allowable passive pressure of 250 pounds per square foot per foot of depth may be used A coefficient of fnction of 0 35 is recommended The soils passive pressure as well as the beanng value may be increased by 1/3 for wind and seismic loadmg SETTLEMENT Settlement of compacted fill soils is normal and should be anticipated Because of the minor thickness of the fill soils anticipated under the proposed footings, total and differential settlements should be within acceptable limits PRESATURATION OF SLAB SUBGRADE Due the granular charactenstics and low expansion potential of the anticipated foundation soils, presoakmg of subgrade pnor to concrete pour is not required However, subgrade soils m areas receiving concrete should be watered pnor to concrete placement to mitigate any drymg shrinkage, which may occur following site grading 10 ARCHIPELAGO DEVELOPMENT/ RAHYARD LOFTS PROJECT NO I3-I106D5 TEMPORARY SLOPES For the excavation of foundations and utility trenches, and during remedial grading, temporary vertical cuts to a maximum height of 4 feet may be constructed in fill or natuial soil Any temporary cuts beyond the above height constramts should be shored or further laid back following a 1 1 (honzontal to vertical) slope ratio OSHA guidelmes for trench excavation safety should be implemented during construction TRENCH BACKFILL Excavations for utility fines, which extend under structural areas should be properly backfilled and compacted Utilities should be bedded and backfilled with clean sand or approved granular soil to a depth of at least one foot over the pipe This backfill should be uniformly watered and compacted to a firm condition for pipe support The remainder of the backfill should be on-site soils or non-expansive imported soils, which should be placed in thin lifts, moisture-conditioned and compacted to at least 90% lelative compaction DRAINAGE Adequate measures should be undertaken to properly finish grade the site after the structure and other improvements are in place, such that the drainage water within the site and adjacent properties is diiected away from the foundations, footings, floor slabs and the tops of slopes via ram gutters, downspouts, suiface swales and subsuiface drams towards the natural drainage for this area A minimum gradient of 1 percent is recommended m hardscape areas For earth areas, a minimum gradient of 5 percent away from the structure for a distance of at least 5 feet should be provided Earth swales should have a mmunum gradient of 2 percent Dramage should be directed to approved drainage facilities Proper surface and subsurface dramage will be required to minimize the potential of water seekmg the level of the beanng soils under the foundations, footings and floor slabs, which may otherwise result in undermining and differential settlement of the structure and other improvements FOUNDATION PLAN REVIEW Our firm should review the foundation plans dunng the design phase to assure conformance with the intent of this report During construction, foundation excavations should be observed by our representaUve pnor to the placement of forms, reinforcement or concrete for conformance with the plans and specifications LIMITATIONS OF INVESTIGATION Our mvestigation was performed usmg the skill and degree of care ordinarily exercised, under similar circumstances, by reputable soils engmeers and geologists practicmg m this or similar localities No other warranty, expressed or iirqilied, is made as to the conclusions and professional advice mcluded m this report This report is prepared for the sole use of our client and may not be assigned to others without the written consent of the client and ECSC&E, Inc. 11 ARCHIPELAGO DEVELOPMENT/ RAILYARD LOFTS PROJECT NO I3-II06D5 The samples collected and used for testmg and the observations made, are believed representative of site conditions; however, soil and geologic conditions can vary sigmficantly between exploration trenches, boreholes and surface exposures As in most major projects, conditions revealed by construction excavations may vary with prelimmary findmgs If this occurs, the changed conditions must be evaluated by a representative of ECSC&E and designs adjusted as required or alternate designs recommended This report is issued with the understandmg that it is the responsibility of the owner, or of his representative to ensure that the information and recommendations contained herem are brought to the attention of the project architect and engineer Appropnate recommendations should be incorporated into the structural plans The necessary steps should be taken to see that the contractor and subcontractors carry out such recommendations m the field The findmgs of this report are vahd as of this present date However, changes m the conditions of a property can occur with the passage of tune, whether they are due to natural processes or the works of man on this or adjacent properties In addition, changes in applicable or appropnate standards may occur from legislation or the broadenmg of knowledge Accordmgly, the findings of this report may be invalidated wholly or partially by changes outside of our control Therefore, this report is subject to review and should be updated after a penod of two years ADDITIONAL SERVICES The review of plans and specifications, field observations and testmg under our direction are integral parts of the recommendations made m this report If East County Soil Consultation and Engmeermg, Inc IS not retamed for these services, the client agrees to assume our responsibility for any potential claims that may anse durmg construction Observation and testmg are additional services, which are provided by our fum, and should be budgeted -withm the cost of development Plates No 1 through 3, Page L-1 and References are parts of this report 12 J V, v •^s*- sf--' 1 I Jr -T .. >_ ft "1 <9^-/ 1 tUJ'Z H <v K V ? \ EAST COUNTY SOIL CONSULTATION & ENGINEERING, INC 10925 HARTLEY RD SUITE I SANTEE, CA 92071 (619) 238 7901 fax (619) 258-7902 4^1:^9^ ^£4^ ^4:, ^e>£7<=f V A^. r-^rv/? AW'/V-^frr Afc . ' ARCHIPELAGO DEVELOP MEHT/KAILYARD LOFTS PROJECT NO I3-II06D5 DEPTH Surface 0 5' 1 5' 2 5 4 0' 5 5' 6 0' 100' PLATE NO. 2 SUMMARY SHEET BOREHOLE NO. 1 SOIL DESCRIPTION GRAVEL UNDOCUMENTED FH^L reddish brown, dry to moist, medium dense, silty sand ti rt n B »i ALLUVIUM (Qal) gray, moist to wet, medium stiff sandy clay n M i» II t» gray brown, moist, medium dense, clayey sand light gray, moist, dense sand with silt bottom of borehole, caving @ 8 5', giound water @9 0' borehole backfilled 2/26/13 BOREHOLE NO. 2 Y 1 11 1 101 4 M 64 24 5 DEPTH SOIL DESCRIPTION Surface GRAVEL 0 5'UNDOCUMENTED FILL gray brown, moist, loose, silty sand 1 0'reddish brown, dry to moist, medium dense, silty sand 2 0'TOPSOIL dark brown, moist, loose, porous, silty sand 25 alluvium (Qal) gray, moist to wet, medium stiff sandy clay 6 0'light gray, moist, dense sand with silt 8 0'bottom of borehole, no caving, no groundwatei borehole backfilled 3/12/13 Y M Y = DR\ DENSITY IN PCF M = MOISTURE CONTENT IN % 13 A RCHIPELAGO DEVELOPMENT/ RAIL YARD LOFTS PROJECT NO 13-1106D5 PLATE NO. 2 (Continued) SUMMARY SHEET BOREHOLE NO. 3 DEPTH SOIL DESCRIPTION Surface TOPSOIL dark brown, moist, loose, porous, silty sand 1 0' UNDOCUMENTED FELL reddish brown, dry to moist, medium dense, siity sand 2 0- alluvium (Qal) g,ray, moist to wet, medium stiff sandy clay 6 0' light gray, moist, dense sand with silt 7 0 bottom of borehole, no caving, no groundwater borehole backfilled 3/12/13 BOREHOLE NO. 4 DEPTH SOIL DESCRIPTION Surface TOPSOIL dark brown, moist, loose, porous, silty sand 2 5' ALLUVIUM (Qal) gray, moist to wet, medium stiff sandy clay 6 0' light gray, moist, dense sand with silt 10 0' bottom of borehole, caving @ 8 5', groundwater @9 0' borehole backfilled 3/12/13 M Y M Y = DR\ DENSITY IN PCF M = MOISTURE CONTENT IN % 14 DEPTH Surface 0 5' 1 5' 2 0' 3 0' 6 0" 7 0' 10 0' 15 0' 20 0' 21 0' 24 0' 25 0 ARCHIPELAGO DEVELOPMENT/ KAILYARD LOFTS PROJECT NO I3-1I06D5 PLATE NO. 2 (Continued) SUMMARY SHEET BOREHOLE NO. 5 SOIL DESCRIPTION TOPSOU. dark brown, moist, loose, silty sand UNDOCUMENTED FELL reddish brown dry to moist, medium dense, silty sand II It n »» " " ALLUVIUM gray moist to wet soft to medium stiff sandy clay 11 IT II n tt rt light gray, moist to wet medium dense to dense sand with silt SANTIAGO FORMATION (Tsa) light colored, moist, dense, sandstone bottom of boiehole, groundwater @9 0' borehole backfilled with bentonite shavings 3/19/13 SPT 18 37 45 78 37 61 98 7 98 3 123 6 M 25 0 24 4 15 1 SPT = STANDARD PENETRATION TEST IN BLOWS/ FT Y = DRY DENSITY IN PCF M ~ MOISTURE CONTENT IN % 15 MAJOR DIVISIONS SYMBOL DESCRIPTION COARSE GRAINED SOILS (MORE THAN Vi OF SOIL > NO 200 SIEVE SIZE) GRAVELS (MORE THAN 'A OF COARSE FRACTION >N0 4 SIEVE SIZE) GW WELL GRADED GRAVELS OR GRAVEL- SAND MIXTURES, LITTLE OR NO FINES GP POORLY GRADED GRAVELS OR GRAVEL-SAND MIXTURES, UTTLE OR NO FINES GM SILTY GRAVELS, GRAVEL-SAND-SILT MDCTURES GC CLAYEY GRAVELS, GRAVEL-SAND-CLAY MIXTURES SANDS (MORE THAN 'A OF COARSE FRACTION < NO 4 SIEVE SIZE) SW WELL GRADED SANDS OR GRAVELLY SANDS, LITTLE OR NO FINES SP POORLY GRADED SANDS OR GRAVELLY SANDS, LITTLE OR NO FINES SM SILTY SANDS, SILT-SAND MDCTURES sc CLAYEY SANDS, SAND-CLAY MIXTURES FINE GRAINED SOILS (MORE THAN 'A OF SOIL < NO 200 SIEVE SIZE) SILTS & CLAYS UQUID LIMIT <50 ML INORGANIC SILTS AND VERY FINE SANDS. ROCK FLOUR, SE-TY OR CLAYEY FINE SANDS OR CLAYEY SILTS WITH SLIGHT PLASTICITY CL INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS OL ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY SILTS & CLAYS UQUID UMIT >50 MH INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE SANDY OR SILTY SOILS, ELASTIC SILTS CH INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS OH ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTY CLAYS ORGANIC SILTS fflGHLY ORGANIC SOILS Pt PEAT AND OTHER HIGHLY ORGANIC SOILS CLASSIFICATION CHART (UNIFIED SOIL CLASSIFICATION SYSTEM) CLASsmc^noN RANGE OF GRAIN SIZES U S STANDARD GRAIN SIZE IN SIEVE SIZE NULLIMETERS BOLLDERS Above 12 Inches Above 305 COBBLES 12 Inches To 3 Inches 30J To 76 2 GRAVEL 3 Inches to No 4 76 2to4 76 Coarac 3 Inches to Vi Inch 76 2 to 19 1 Fme V4 Inch to No 4 19 I to 4 76 SAND No 4 to No 200 4 76 to 0 074 Coarse No 4 to No 10 4 76 to 2 00 Medium No 10 to No 40 2 00 to 0 420 Fme No 40 to No 200 0 420 to 0 074 SILT AND CLAY Below No 200 Below 0 074 t rf li / [»>«*«• »f * • •• mtm WU.-U1 f -arj LIQUID LIHIT (U.) GRAIN SIZE CHART PLASTICITY CHART EAST COUNTY SOIL CONSULTATION AND ENGINEERING, INC 10925 HARTLEY ROAD, SUITE "I" SANTEE, CALIFORNU 92071 U.S.C.S. SOIL CLASSIFICATION RaI,//ARD lofts project PROJECT NO. L3-1106D5 PLATE NO. 3 liARCrt Jl ^013 ARCHIPELAGO DEVELOPMENT/ KAILYARD LOFTS PROJECT NO I3-II06D5 PAGE L-1 LABORATORY TEST RESULTS EXPANSION INDEX TEST (ASTM D4829) INITIAL MOISTURE CONTENTI%') SATURATED MOISTURE CONTENTr%) INITIAL DRY DENSITY (PCF) 11 1 142 23 3 29 3 106 7 96 8 EXPANSION INDEX 33 151 LOCATION BH-1 @2 0' BH-1 @ 11 0' PARTICLE SIZE ANALYSIS (ASTM D422) US Standard Sieve Size Percent Passing BH-1 @ 1 5' Fill Percent Passing BH-1 @3 0' Alluvium Percent Passmg BH-1 @5 5' Alluvium Percent Passmg BH-l @8 0' Alluvium Percent Passmg BH-5 @ 24 0' Santiago Form 2" 1" 1/2" 3/8" #4 m #16 #30 #50 #100 #200 100 99 98 92 63 37 27 100 94 82 69 63 100 99 94 70 40 32 100 99 97 86 38 11 6 100 97 82 59 35 24 19 uses SM CL SC SP-SM SM 16 ARCHIPELAGO DEVELOPMENT/ KAILYARD LOFTS PROJECT NO I3-II06D5 REFERENCES 1 "2010 California Building Code, California Code of Regulations, Title 24, Part 2, Volume 2 of 2", Published by International Code Council 2 "Eqfault/ Eqsearch, Version 3 0", by Blake, T F , 2000, Updated 2008 3 "Geotechnical and Foundation Engineering Design and Construction", by Robert W Day, 1999 4 "1997 Uniform Building Code, Volume 2, Structural Engineering Design Provisions", Published by International Conference of Building Officials 5 "Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada to be used with the 1997 Uniform Building Code", Published by International Conference of Building Officials ' 6 "Geologic Maps of the Northwestern Part of San Diego County, California", Department of Conservation, Division of Mines and Geology, by Siang S Tan and Michael P Kennedy, 1996 7 "Bearing Capacity of Soils, Technical Engineenng and Design Guides as Adapted from the US Army Corps of Engineers, No 7", Published by ASCE Press, 1994 8 "Foundations and Earth Structures, Design Manual 7 2", by Department of Navy Naval Facilities Engineenng Command, May 1982, Revalidated by Change I September 1986 9 "Ground Motions and Soil Liquefaction during Earthquakes", by H B Seed and I M Idriss, 1982 17