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HomeMy WebLinkAbout; Two Retail Structures- Pad 4 and Pad 6; Geotechnical Investigation Report; 2005-04-05I I I I I I I Geotechnical Investigation Report Two Retail Structures - Pad 4 and Pad 6 7190 Avenida Encinas Carlsbad, California Prepared For: Mr. Clint Knox Donahue Schriber Realty Group, Inc. 200 E. Baker Street, Suite 100 Costa Mesa, California 92626 Converse Project No. 05-32123-01 April 5, 2005 I Converse Consultants " '^^j^^r ^v®'' Years of Dedication in Geotechnicai Engineering and Environmental Sciences I I I I I I I I I April 5, 2005 Mr. Clint Knox Donahue Schriber Realty Group, Inc. 200 E. Baker Street, Suite 100 Costa Mesa, Caiifornia 92626 Subject: GEOTECHNICAL INVESTIGATION REPORT Two Retail Structures - Pad 4 and Pad 6 7190 Avenida Encinas Carlsbad, California Con verse Project No: 05-32123-01 Dear Mr. Knox: Presented herein are the results of the geotechnical investigation performed by Converse Consultants (Converse) for the two proposed retail structures at Pad 4 and Pad 6, located at 7190 Avenida Encinas in Cadsbad, Caiifornia. This work was performed in accordance with our proposal dated March 7, 2005, and your authorization dated March 10, 2005. Submittal of this report completes our scope of work for this project. Plan review, representation at meetings, consultation, performance of any further studies required by reviewing agencies, and subsequent earthwork observation and testing services are beyond our current scope of work and would require separate contracts. Thank you for the opportunity of working with you on this project. If there are any questions, please call us at 714-444-9660. We look forward to assisting you during construction. Yours truly, CONVERSE CONSULTANTS William H. Chu, G.E. Sr. Vice President/Principal Engineer KN/klf Dist: Addressee (4) 185 East Paularino Avenue, Suite B, Costa Mesa, California 92626 Telephone: (714) 444-9660 • Facsimile: (714) 444-9640 • e-mail: costamesa@converseconsultants.com Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carlsbad, Caiifomla March 5, 2005 Page ii PROFESSIONAL CERTIFICATION This report has been prepared by the staff of Converse Consultants (Converse) under the professional supervision of the individuals whose seals and signatures appear hereon. The findings, recommendations, specifications or professional opinions contained in this report were prepared in accordance with generally accepted professional engineering and engineering geologic principles and practice in this area of California. There is no warranty, either expressed or implied. Krishnamenon Nadaraja, P.E. Project Engineer ^-i^VroTT'^SK Catm-ene Glick, C^.GytH.G. \ - \ Seriior Geologist/Hyd)^geologi'?t \ ' Converse Consultants K:\PROJECT FILE\05-32 123-01 Two PROPOSED RETAIL STRUCTURE AT CARLSBAD\05-32123-01-GIR.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carlsbad, Califomia March 5, 2005 Page iii TABLE OF CONTENTS 1.0 INTRODUCTION 1 2.0 PROJECT DESCRIPTION 1 3.0 PURPOSE OF STUDY 1 4.0 FIELD EXPLORATION AND LABORATORY TESTING 2 4.1 FIELD EXPLORATION 2 4.2 LABORATORY TESTING 2 5.0 SITE AND SUBSURFACE CONDITIONS 2 5.1 SITE DESCRIPTION 2 5.2 GEOLOGIC SETTING 2 5.2.1 SITE GEOLOGY 3 5.3 SUBSURFACE CONDITIONS 3 5.4 GROUNDWATER 4 6.0 FAULTING AND SEISMICITY 4 FAULTING 4 6.2 SEISMICITY 4 6.3 SEISMIC COEFFICIENTS 4 6.4 GEOLOGIC HAZARDS DUE TO SEISMIC ACTIVITIES 5 7.0 CONCLUSIONS AND RECOMMENDATIONS 6 7.1 GENERAL 6 7.2 DISCUSSION OF FOUNDATION ALTERNATIVES 7 7.3 SITE PREPARATION AND GRADING 8 7.4 TEMPORARY CONSTRUCTION SLOPE AND SHORING 9 7.5 FOUNDATION SUPPORT 10 7.5.1 SHALLOW FOUNDATION 10 7.5.2 DRILLED PILES 11 7.5.3 GEOPIER FOUNDATION 12 7.5.4 MAT FOUNDATION 13 7.5.5 FLOOR SLABS 13 7.5.6 CONCRETE FLATWORK 14 7.6 LATERAL LOADS 14 7.7 SURFACE DRAINAGE 15 7.8 UTILITIES 15 7.9 SOIL CORROSIVITY 15 7.10 PLAN REVIEW, OBSERVATIONS AND TESTING 16 8.0 CLOSURE 16 REFERENCES 17 FIGURE FIGURE NO. 1 - SITE AND BORING LOCATION PLAN FOLLOWS PAGE 1 APPENDICES APPENDIX A - FIELD EXPLORATION A-1 THROUGH A-5 APPENDIX B - LABORATORY TESTING B-1 THROUGH B-8 APPENDIX C - EARTHWORK SPECIFICATIONS C-1 THROUGH C-4 @ Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carlsbad, Califomia March 5, 2005 Page 1 1.0 INTRODUCTION This report presents the results of our geotechnical investigation performed for the two retail structures at Pad 4 and Pad 6, located at 7190 Avenida Encinas in the City of Carlsbad, County of San Diego, California. The location ofthe project is shown on Figure No. 1, Site and Boring Location Plan. 2.0 PROJECT DESCRIPTION Based on the information provided to our office, it is our understanding that the project sites (Pad 4 and Pad 6) are for a commercial/retail center and that two (2 single-story retail structures will be constructed. The proposed structures at building pad 4 and pad 6 will have building footpnnts of approximately 5,800 and 5,000 square feet, respectively. A grading plan was not available at the time of our investigation. The structures will be built essentially on/or near the existing surface. Although it appeared that the sites were previously graded, we were not provided documentation forthe previous development. 3.0 PURPOSE OF STUDY The purpose of this study was to: (1) obtain information on the subsurface conditions within the proposed development area, (2) evaluate the data, and (3) provide conclusions and recommendations for site grading, foundation design, and construction ofthe proposed residential development as influenced bythe subsurface conditions. To accomplish these objectives, we: 1. Collected and reviewed available geologic, boring, earthwork information, and available project data. 2. Prepared a field exploration program. 3. Performed a site reconnaissance and located the borings in the field. 4. Acquired permit from the San Diego County, Department of Environmental Health, Monitoring Well Program. 5. Engaged a drilling contractor to perform test borings, and logged the borings. 6. Backfilled the boreholes with bentonite chips and grout per SAM Manual. 7. Performed laboratory tests to aid in classification of the materials sampled and to obtain data on their engineering properties. 8. Correlated, interpreted, analyzed, and evaluated the data obtained. 9. Prepared this report to present our conclusions and recommendations. Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC Existing Chevron Gas Station LEGEND 8-4 INDICATES NUMBER AND APPROXIMATE LOCATION OF BORING APPROXIMATE SCALE i" = 120' SITE AND BORING LOCATION PLAN TWO RETAIL STRUCTURES Carlsbad, California For: Donahue Schriber Realty Group, Inc. Project No. 05-32123-01 ^7 r^»r.w»ro« r^»r.o..l«o»to Geotechnlcal Engineering Converse Consultants and Applied sciences Figure No. 1 Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carisbad. California March 5, 2005 Page 2 4.0 FIELD EXPLORATION AND LABORATORY TESTING 4.1 Field Exploration A total of four (4) test borings ( BH-1 through BH-4) were drilled on Pad 4 and Pad 6 (two (2) borings per site) on March 25 and March 28, 2005 at the locations shown on Figure No. 1, Site and Boring Location Plan. The borings were drilled with a hollow- stem auger drill rig to depths ranging from 2672 to 5172 feet below the existing grade. Logs of the subsurface conditions, as encountered in the test borings, were recorded at the time of drilling and are presented on the boring logs included in Appendix A, Field Exploration. Relatively undisturbed nng samples and bulk samples of subsurface matenals were obtained at frequent intervals below the ground surface and were taken to the laboratory for classification and testing. In addition. Photo Ionization Detector (PID) tests were performed on the cuttings to detect potential hydrocarbon contamination. All borings were backfilled with bentonite chips and grout at the completion of dniling and the drilled cuttings were drummed per our proposal. A brief descnption of the drilling and sampling operation is included in Appendix A, Field Exploration. 4.2 Laboratory Testing Representative soil samples were tested in the laboratory to obtain engineering properties of the subsurface soils. Laboratory tests included unit weight, moisture content, maximum dry density and optimum moisture content, gradation, percent passing the No. 200 sieve, direct shear, consolidation, expansion index, and corrosivity (sulfate and chloride content, pH and electrical resistivity). Detailed descriptions of the laboratory tests are presented in Appendix B, Laboratory Testing along with the tabulated test results. Soil samples will be discarded 30 days after the date of this report, unless this office receives a specific request to retain the samples for a longer period of time. 5.0 SITE AND SUBSURFACE CONDITIONS 5.1 Site Description The sites will consist of Pad 4 and Pad 6 with a floor area of 5800 square feet and 5000 square feet, respectively. At the time of our field investigation, the pads were vacant. 5.2 Geologic Setting The project site lies along the central coastal margin of the Peninsular Ranges Geomorphic Province of California. The Peninsular Ranges province is charactenzed by northwest trending valleys and mountain ranges, which have formed in response to the regional tectonic forces along the boundary between the Pacific and North American tectonic plates. The geologic structure is dominated by northwest trending right-lateral faults, most notable, the San Andreas Fault, San Jacinto Fault, Elsinore Fault and Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carisbad, California March 5, 2005 Page 3 Newport-Inglewood Fault. This Province extends southward from the Transverse Ranges at the north end of the Los Angeles basin to the southern tip of the Baja California peninsula. The coastal margin of the Peninsular Ranges has undergone coastal and marine erosion during the past one million years (Holocene and Pleistocene Epochs). Marine erosion and wave action has cut terraces into the coastal margin. During the final Pleistocene glacial stage (about 14 to 16 thousand years ago), the sea level was lowered about 200-300 feet. This forced streams crossing the terraces to cut deep gullies and canyons into the terrace platforms and readjust to the new base sea levels. The amount of down cutting and width of the channel or valley was dependent on the size of the stream tributary or river. As the continental ice sheets melted and the postglacial sea levels rose, the lower ends of the channels and valleys were flooded by the rising ocean and filled with sediments from stream deposition and shoreline processes. The channels mouths were gradually filled along the coastline with continental alluvial deposits to form the present day estuaries and partially filled channel features. The project site is not located within a currently designated State of California Earthquake Fault-Rupture Hazard Zone. No faults with evidence of surface rupture are known to project through or towards the project site. The site is located along the coastal margin between the active Elsinore Fault and the offshore Newport-Inglewood Fault. 5.2.1 Site Geology The project site is underlain by up to 1,500 feet of Holocene, interbedded marine and non-manne sand and gravel sediments with thin interstitial sandy- to silty clay lenses typical of Point Loma Formation. A thick section of non-marine sedimentary rocks, interbedded cobble, conglomerates and Sandstone lenses ranging in age from Pliocene to Cretaceous, underties the site at depth. The soil borings advanced for this project encountered interbedded sand and clayey sand sequences to the extent drilled (5iy2-feet below ground surface) which are typical ofthe Point Loma Formation sediments previously described. 5.3 Subsurface Conditions In our recent exploration, fill was encountered up to five (5) feet and seven (7) feet in our borings at the site for Pad 6 and Pad 4, respectively. The fill is likely to be associated with the previous grading, however we were not provided the documentation related to the previous development. At this time we will consider this fill as undocumented fill material consisting of sands, clayey and silty sands. The fill materials are underlain by native soils to the maximum explored depth of 5172 feet below existing ground surface. The native soils are composed of mainly sands, silty and clayey sands and clay. The near surface soils have a very low expansion potential and are not sensitive to moisture variation, Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carisbad, California March 5, 2005 Page 4 5.4 Groundwater Groundwater was encountered in all of the borings between 20 and 21 feet below the existing ground surface at the end of drilling. Based on our review of available groundwater data, high groundwater could be within 10 feet of the existing grade. It should be noted that the depths to groundwater could vary depending upon season, precipitation, and possible groundwater pumping activity in the vicinity. 6.0 FAULTING AND SEISMICITY Faulting Based on our review of the available information, there are no known active faults projecting toward or extending across the project site. An active fault is defined as one that has surface displacement within Holocene time (about the last 11,000 years). The site is not situated within a currently designated State of California Earthquake Fault Zone. The nearest known active faults are the Rose Canyon fault located about 5 miles southwest of the site. The Newport Inglewood (offshore) and Coronado Bank faults are located approximately 6.5 miles and 21.5 miles, respectively, northwest ofthe site. 6.2 Seismicity The site for two retail structures is situated in a seismically active region. As is the case for most areas of southern California, ground-shaking resulting from earthquakes associated with both nearby and more distant faults is likely to occur. During the life of the project, seismic activity associated with active faults in the area may generate moderate to strong ground shaking at the site. Earthquake intensities will vary throughout southern California, depending upon the magnitude of the earthquake, the distance from the active fault, and the type of material underiying the site. The site will probably be subjected to at least one moderate to severe earthquake during the next 50 years that will cause strong ground shaking. Based on our evaluation, the site could be subjected to an average peak ground acceleration of approximately 0.35g with a 10 percent probability of exceedance in 50 years, based on attenuation relationships by Campbell & Bozorgnia (1997), Joyner & Boore (1997), and Sadigh et al. (1997). 6.3 Seismic Coefficients Based on the results of our borings and laboratory testing, and in accordance with the 1997 Uniform Building Code (UBC)/2001 California Building Code (CBC), the site should be considered as having a So soil profile. The site is located within Seismic Zone 4 in accordance with the UBC/CBC. The following seismic coefficients are considered appropriate for analysis: Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carisbad, California March 5, 2005 Page 5 Seismic Zone Factor, Z 0.40 Soil Profile Type So Seismic Source Type B Seismic Coefficient, Na 1.0 Seismic Coefficient, Nv 1.2 Seismic Coefficient, Cg 0.44 Na Seismic Coefficient, Cv 0.64 Nv 6.4 Geologic Hazards Due to Seismic Activities Historical evidence and current technology indicate that at least one moderate to severe earthquake will occur during the design life of the site. During a moderate to severe earthquake occurring on the nearby faults, strong ground shaking of the project site will probably occur. In addition to ground shaking, effects of seismic activity on a project site may include surface fault rupture, soil liquefaction, and seismically induced differential settlement of structures, ground lurching, land sliding, lateral spreading, earthquake- induced flooding, seiches, and tsunamis. Results of a site-specific evaluation of each of the above possible secondary effects are explained below: Surface Fault Rupture The project site is not located within a currently designated State of California Earthquake Fault Zone. Based on our review of existing geologic information, no known major surface fault crosses through or extends towards the site. The potential for surface rupture resulting from the movement of a previously unrecognized fault is not known with certainty but is considered low. Liquefaction Potential Soil liquefaction is a phenomenon that occurs when saturated cohesionless soil layers, located within about 50 feet of the ground surface, lose strength during cyclic loading, as caused by earthquakes. During the loss of strength, the soil acquires "mobility" sufficient to permit both horizontal and vertical movements. Soils that are most susceptible to liquefaction are clean, loose, saturated, and uniformly graded, fine- grained sands that lie below the groundwater table within a depth usually considered to be about 50 feet. The factors known to influence liquefaction potential include soil type and depth, grain size, density, groundwater level, degree of saturation, and both the intensity and duration of ground shaking. Based on our recent subsurface exploration, the subsurface soils to a depths of about 5172 feet consist of predominantly dense to very dense sand, clayey and silty sand, and very stiff clay. It is our opinion that the potential for liquefaction of the dense to very dense sandy soils below historical high ground water (within 10 feet) at the site is very low. Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Cartsbad, Caiifornia March 5, 2005 Page 6 Landslides Seismically induced landslides and other slope failures are common occurrences in areas of significant ground slopes during or soon after earthquakes. The site is relatively flat therefore there is no potential for seismically induced landslides affecting the site. Lateral Spreading Seismically induced lateral spreading involves lateral movement of earth materials due to ground shaking. It differs from a slope failure in that ground failure involving a large movement does not occur due to the flatter slope of the initial ground surface. Lateral spreading is characterized by near-vertical cracks with predominantly horizontal movement of the soil mass involved over the liquefied soils. The potential for lateral spreading at the subject site is considered low. Differential Settlement Due to Seismic Shaking The potential of differential settlement due to seismic shaking exists forthe sandy layers that are potentially liquefiable. Based on our review, site soils are not prone to liquefaction thus, liquefaction-induced settlement and with differential seismic settlement is very low. Tsunamis Tsunamis are tidal waves generated in large bodies of water by fault displacement or major ground movement. The site is within a mile from the Pacific Ocean. Based on the site location and elevation there is a low to moderate risk of tsunamis at this site. Seiches Seiches are large waves generated in enclosed bodies of water in response to ground shaking. Based on our review, no significant dams or other enclosed bodies of water are present in the vicinity of the site. It is our opinion that the potential for damage due to seiches is considered low. Earthquake-Induced Flooding Flooding may be caused by failure of dams or other water retaining structures due to earthquake. Based on our review, no significant dams or other enclosed bodies of water are present in the vicinity of the site. The potential for earthquake-induced flooding is considered low. 7.0 CONCLUSIONS AND RECOMMENDATIONS 7.1 General Based on the results of our field and laboratory exploration, in conjunction with engineering analysis and our experience and judgment, it is our professional opinion that the sites for Pad 4 and Pad 6 are suitable for the proposed retail structures from a Converse Consultants M:\JOBFiLE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carisbad, Califomia March 5, 2005 Page 7 geotechnical engineering standpoint provided that the recommendations presented herein are incorporated in the design and construction of the project. The primary geotechnical considerations for foundation design are as follows: Undocumented Fill: Up to a depth of 5 feet and 7 feet of fill encountered in the vicinity of Pad 6 and Pad 4, respectively. No documentation was available at the time of this report to verify that the fill was placed in accordance with engineering standards. Based on dry density tests, and laboratory maximum dry density and optimum moisture content test results, the relative compaction of the fill was found to be about 90 percent or above except for the sample taken at 5 feet at boring BH-4. The non-uniform nature ofthe fill is considered to have the potential to experience detrimental differential settlement. Unless this office verifies the fill uniformity by performing a series of density tests in selected test pits for every 15 feet grid, along with the Cone Penetrometer Testing (CPT), the fill will be considered as undocumented fill and not acceptable for foundation support. This potential future investigation is beyond our scope and current contract and it is not guarantied that fill soils can be acceptable at the end ofthe investigation. The undocumented fill material is not suitable for foundation support without some form of ground improvement. The structures should be supported on either a shallow foundation system founded on improved soils/engineered fill or a deep foundation. 7.2 Discussion of Foundation Alternatives Several alternatives were evaluated for foundation support of the structures. The selected alternatives should be based on effectiveness of the system and economics. The alternatives are presented below: Conventional Footing with Fill Removal and Replacement: To minimize the potential of the structures undergoing adverse settlements due to the non-uniformity of the near surface soils, we recommend that all fill and the upper soils within the footprint of the proposed building be entirely removed and replaced as compacted fill. This compacted fill should extend a minimum of two (2) feet below the bottom of all footings and slabs. The removal and re-compaction should extend at least five (5) feet beyond the limits of the building and appendages. The building may then be supported on conventional shallow spread and continuous footings founded on the compacted fill. The removal and total replacement of the undocumented fill is feasible and typically cost effective when fill thickness limited to be less than 8 feet. Drilled Piles: Drilled piles can be used as an alternate foundation system to support the proposed structure. Drilled piles are typically not considered ideally suitable in areas with Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carisbad, California March 5, 2005 Page 8 groundwater and the potential for caving soils conditions. For drilled piles to be properly installed, the use of bentonite slurry is required to stabilize the hole below the groundwater level. In addition, concrete should be placed by pump with the tremie method. Geopier Foundation System: As an alternative, a Geopier foundation system may be used to improve and reinforce the undocumented fill to support the slabs and footings. Geopier elements are relatively small diameter holes and the high frequency impact energy does not cause resonant action in soils, as does pile driving, since soils have a natural low frequency. A Geopier foundation system is a practical refinement to the traditional over excavation and replacement method by strengthening and selectively removing the subsoils for settlement control and bearing capacity improvements. The Geopier support is constructed by drilling a limited depth shaft, by removing a volume of compressible/loose subsoil materials, then installing a bottom bulb of clean, open- graded stone while vertically prestressing and prestraining the subsoils beneath the bottom bulb. The Geopier shaft is built on top of the bottom bulb, using well-graded highway base course placed in thin lifts (12 inches compacted thickness). Densification of the bottom bulb and the shaft fill is accomplished by using the impact ramming action of a modified hydraulic hammer/tamper. The tamper consists of a special steel alloy shaft and a round beveled tamper head. The beveled tamper head assists in transferring force vertically and laterally during impact densification, resulting in pushing of aggregate against the confined walls of the cavity. In addition to increasing shear resistance at the Geopier element perimeter, the increased horizontal stress in the matrix soil improves the composite material and makes it stiffer. Mat Foundation: As an alternative to the complete removal and replacement, mat foundation in conjunction with limited removal and re-compaction of the undocumented fill may be used to support the structures associated with the expansion. We recommend that the existing fill beneath the mat foundation be removed to a depth of three (3) feet and be re-compacted. In addition, the compacted fill should be underiain by a layer of geosynthetic fabric to provide additional tensile reinforcement. Mat foundation is a more rigid system and is capable of spanning pockets/cavities associated with compression of the underiying undocumented fill or seismically induced settlement. 7.3 Site Preparation and Grading The locations of the proposed structures should be cleared of all surface items, near surface disturbed soil, highly organic topsoil, deleterious materials, vegetation and utilities. For structures to be supported by mat foundation, a minimum removal and re- compaction of four (4) feet below the mat should be provided. The removal and re- compaction should extend at least five (5) feet beyond the limits (or to the extent Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carisbad, California March 5, 2005 Page 9 possible) of the foundation. For concrete flatwork, driveway, parking, and for minor non- load bearing structures, a minimum of 12 inches of removal and re-compaction is recommended. The actual depth of removal and re-compaction should be determined in the field by the geotechnical engineer at the time of construction. Fill for the building pad should not contain rocks or lumps larger than three inches. Additional excavation may be necessary if any disturbed soil or other unsuitable deposits are exposed. We recommend that the exposed surface be scarified to a minimum depth of six (6) inches and be compacted to a minimum density of 90 percent relative compaction as determined by ASTM Designation Dl 557-00. The excavated on-site soils may be reused as compacted fill provided they are free of deleterious substances, and are relatively free of the cobble and boulder size particles discussed above. Any soils imported from off-site sources for use within the structure areas and to five (5) feet beyond the building limits should be non-expansive with an expansion index of less than 20, and be approved by the geotechnical engineer prior to placement. Acceptable fill material should be placed in lifts not exceeding eight (8) inches in thickness when loose and should be properly compacted to at least 90 percent of the maximum dry density as determined by ASTM Test Method Dl 557-00. On-site materials should be compacted with the water content at, or within two (2) percent of the optimum as determined from ASTM Test Method D1557-00. The placement and compaction of all fill should be performed under the observation and testing of Converse Consultant's representative. Shrinkage is the loss of soil volume caused by compaction of the soil to a density greater than before grading. For an earthwork volume estimate, a shrinkage value on the order of 10 to 15 percent may be assumed for the near surface soils. 7.4 Temporary Construction Slope and Shoring Based on our borings, the over excavation forthe grading operation, in our opinion, may be accomplished with conventional excavation equipment. The excavations are not expected to stand vertically for any extended period of time, and all excavations must be sloped or shored. Where sufficient space is available for a sloped excavation, the excavations in the medium dense sand deposits should be sloped no steeper than 1:1 (horizontal to vertical). The exposed slope faces should be kept moist and not allowed to dry out. The Table No.l, Slope Ratio for Temporary Excavations may be used for temporary open cut trenches or excavations. Temporary cuts encountering soft and wet fine-grained soils; dry cohesionless soils or loose fill may have to be constructed at a flatter gradient than presented below. Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carisbad, California March 5, 2005 Page 10 Table No. 1, Slope Ratios for Temporary Excavations Depth of Cut Recommended Maximum Slope (Horizontal: Vertical)^ 0-3 Vertical 3-5 0.5:1 i 5-7 1:1 7-12 1.5:1 ^Slope ratio assumed to be uniform from top to toe of slope. For steeper temporary construction slopes or deeper excavations, or unsuitable soil encountered during the excavation, shoring should be provided by the contractor, as necessary, to protect the workers in the excavation. Surcharge loads should not be permitted within five feet from the top of the slopes, unless the cut is properiy shored. The contractor should be aware that neither slope height, slope inclination, nor excavation depths should exceed those specified in local, state or federal safety regulations, e.g. OSHA Health and Safety Standards for Excavations, 29 CFR Part 1926, or successor regulations. Such regulations are strictly enforced and, if violated, the owner and/or the contractor could be liable for substantial penalties. Construction of open cuts adjacent to existing structures, including underground pipes, is not recommended within a 1:1 (horizontal: vertical) plane extending beyond and down from the perimeter of the structure. Cuts that are proposed within five (5) feet of light standards, other utilities, underground structures and pavement should be provided with temporary shoring. For excavations extending to a depth more than 20 feet, OSHA requires the side slopes and shoring for such excavations be designed by a professional engineer registered in the State of California. It is important to note that soil and groundwater conditions may vary significantly within the footprint of the expansion. Our preliminary soil classifications are based solely on the materials encountered at the actual boring locations. The contractor should verify that similar conditions exist throughout the proposed area of excavation. If different subsurface conditions are encountered at the time of construction, we recommend that our office be contacted immediately to evaluate the conditions encountered. 7.5 Foundation Support 7.5.1 Shallow Foundation The proposed building may be supported on continuous or isolated spread footings founded on at least two (2) feet of compacted fill. All continuous interior and isolated spread footings should be founded at least 24 inches below the lowest adjacent final grade and should be at least 18 inches wide. Continuous perimeter footings should be Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-G1R.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carisbad, California March 5, 2005 Page 11 at least 18 inches wide and 24 inches below the finished subgrade. Footing design may be based on a maximum allowable net bearing value of 2,000 psf for continuous and isolated spread footings. This value may be increased by 33 percent for transient wind and seismic forces. Based on anticipated loads, total and differential settlement of the structure designed in accordance with the recommendations provided in this report is expected to be within tolerable limits for this type of construction. For example, settlement of a five (5) foot square footing is expected to be within 72 inch, with differential settiement between footings to be within 7 inch. Most of the settlement is expected to occur during construction. 7.5.2 Drilled Piles Drilled pile is another alternative foundation system and the piles deriving their capacities primarily from the native soils about 5 feet below the existing grade. We recommend that the grade beam, footings, and slab be supported on the piles if piling is the selected alternate. The allowable design capacities for recommended minimum pile length of 15 feet for 18-inch and 24-inch diameter piles are 30 kips, and 40 kips respectively. The capacities were computed by using a safety factor of three (3) and two (2) for end bearing and skin friction, respectively. The settlement of a single pile is expected to be about one-fourth (7) inch. The vertical capacities above may be increased by 33 percent to resist transient downward vertical loads, such as wind forces or seismic shaking. Pile uplift design capacities may be taken as 50 percent of the vertical downward pile design values shown. The center-to-center spacing between piles should not be less than three (3) times the pile diameter. Allowable axial loads of pile groups with center-to-center pile spacing of less than three (3) pile diameters should be determined by incorporating an efficiency reduction factor to the allowable axial loads for single piles. To maintain the stability of the borehole for the drilled pile, the use of bentonite slurry is recommended below the groundwater table while advancing the excavation to the final depth. Drilled pile excavations should be filled with concrete on the same day they are drilled. The drilling for piles should not be performed adjacent to recently excavated or recently poured piles until the concrete in the completed piles has been allowed to set for several hours. In addition, the piles should also be poured in a manner that will not result in concrete flowing into adjacent open pile excavations. Piles in groups should be drilled and poured in an alternating sequence to minimize the potential for fresh concrete flowing into adjacent open pile excavations. The placement of reinforcement and concreting operations should conform to ACI and other applicable code requirements. Concrete placement should be continuous from the bottom to the top of the drilled pile. Concrete placement should continue after the Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carisbad, California March 5, 2005 Page 12 borehole is filled until good quality concrete is evident at the top of the shaft. Concrete should be placed through a tremie or pump system and the discharge end of the tremie/orifice should be immersed at least 5 feet in concrete at all times after the start of the concrete flow. In addition, the level of concrete in the tremie should be maintained above the level of slurry in the borehole at all times to prevent slurry intrusion into the shaft concrete. We recommend that the installation of the drilled piles be performed with the obsen/ation of Converse Consultants. 7.5.3 Geopier Foundation As an alternative to the piling system, the structures associated with the expansion may be supported on shallow footings or mat foundation founded on a Geopier foundation system. Geopier elements should be designed and installed by a licensed Geopier foundation installer. The design of the Geopier system should be reviewed by Converse and installed under our observation. The design should meet the following: • Maximum overall post-improvement settlement = Vz inch • Maximum post-improvement differential settlement = 7 inch per 100 feet • Minimum composite allowable bearing pressure = 3,000 pounds per square foot (Min F.S. = 3.0). • Minimum Geopier diameter = two (2) feet • Minimum Geopier length = 10 ft. • Minimum Geopier element stiffness = 250 pci. • Minimum uplift capacity per geopier = 40 kips For uplift application, the geopier element should be structurally connected to the footing by means of steel rebar. Proof of the effectiveness of the Geopier system is typically provided by a full-scale Geopier Modulus Load Test on site to verify design assumptions and uplift capacity. The test provides a conservative measure of the stiffness of the Geopier element and will help establish installation procedures forthe project. Continuous and isolated spread footings should be founded at least 24 inches below the lowest adjacent final grade and should be at least 24 inches wide. Footing design may be based on a maximum composite allowable net bearing value of 3,000 psf for continuous and isolated spread footings. This value may be increased by 33 percent for transient wind and seismic forces. For mat foundation supported on the geopier element, a maximum composite allowable net bearing value of 2,000 psf can be used. In addition, a modulus of subgrade reaction between 150 to 200 pounds per square inch per inch can be used forthe design ofthe mat. Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carisbad, California March 5, 2005 Page 13 Based on anticipated loads, total and differential settlement ofthe structure designed in accordance with the recommendations provided in this report is expected to be within tolerable limits for this type of construction. Most of the settlement is expected to occur during construction. If a Geopier system is considered, we recommend that the local Geopier installer in southern California be contacted to review and analyze the subsurface data in this report to provide a preliminary design, cost and time estimate. The information forthe installer is as follows: Geopier Foundation Company - West 570 Giotto, Irvine, CA 92614 Tel: 949-387-8863, Fax: 949-387-7772 Attn: Mr. Ken Hoevelkamp We recommend that the Geopier installer's operations be monitored by Converse full- time as a Quality Assurance service to supplement the installer's internal Quality Control (QC) program. The QC program will monitor drill depths, Geopier element lengths, average lift thicknesses, installation, aggregate quality, and densification of lifts. These items will be documented for each Geopier element installed to provide a complete installation report. 7.5.4 Mat Foundation As another alternate to the piling and geopier foundation system, the structures may be supported on a reinforced mat foundation bearing on a layer of compacted fill. The mat may be designed for a net bearing pressure of 1,500 psf for combined dead plus live loads with one-third increase for all loads including wind or seismic. The total static settlements ofthe structural slab underthe anticipated structural loads and the potential settlement due to compression of the underiying undocumented fill settlement is estimated to be about one (1) inchs with differential settlement on the order of about 72- inche. In addition, a modulus of subgrade reaction of between 150 pounds per square inch per inch can be used for the design of the mat. Mat foundation may be supported on at least three (3) feet of properiy compacted fill. We recommend that a layer of geotextile reinforcing fabric such as Mirafi HP570 be placed on the subgrade to provide additional tensile reinforcement against potential compression of the underiying fill prior to replacement of the upper fill. 7.5.5 Floor Slabs If slab is used for the building, we recommend that the slab be supported on at least three (3) feet of properiy compacted fill or the piles or be reinforced with the Geopier element. Slabs supported on piles or the Geopiers element must be adequately reinforced in both directions or sectionalized with structural separations to control cracking. Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carisbad, California March 5, 2005 Page 14 If migration of moisture through the slab is undesirable, we recommend that a moisture barrier such as an 8-mil polyethylene sheet be used under new slabs. The moisture barrier should be covered with two (2) inches of coarse sand to facilitate concrete curing and to protect the polyethylene sheet. Adequate provisions should be made to limit and/or prevent moisture content changes in the subgrade beneath slabs. These include: positive drainage away from building foundations with a minimum gradient of two (2) percent; impervious cut-off barriers along exterior walls adjacent to landscape planters; and properiy sealed joints for interior piping beneath interior and exterior slab areas. The cut-off barrier can consist of "thickened edge" at least 12-inches wide along the perimeter ofthe slabs. 7.5.6 Concrete Flatwork All exterior slabs and concrete flatwork including the sidewalks should be supported directly on at least 12 inches of properiy compacted fill. We recommend that concrete slabs be at least six inches thick and be properiy reinforced in accordance with the structural requirements. 7.6 Lateral Loads Resistance to lateral loads can be assumed to be provided by passive earth pressure and by friction acting on structural components in permanent contact with the subgrade soils, by the pile caps, and by the lateral resistance ofthe piles. Passive earth pressure on the sides of footings, grade beams or pile caps may be assumed equal to that exerted by an equivalent fluid weighing 275 pcf, subject to a maximum pressure of 2,000 psf A coefficient of friction of 0.40 may be assumed with dead load forces of slab-on-grade/mat in permanent contact with subgrade soils. A friction factor of 0.3 is considered appropriate for concrete slabs underiain by a moisture barrier. No friction is allowed for pile supported structural components, or footing supported structural slabs. Lateral Load design criteria for auger pressure grouted pile are presented below: Recommended Pile Design Parameters for Lateral Loads FIXED-HEAD DIMENSION 18-in 24-in Maximum All. Lateral Load Capacity (kips) 21 37 Maximum Negative Moment (kip-ft) 115 250 Maximum Positive Moment (kip-ft) 36 73 Depth to Maximum Negative Moment (ft) 0 0 Depth to Maximum Positive Moment (ft) 10 12 First Point of Zero Lateral Displacement (ft) 16 18 Depths to Zero Moments (ft) 5.5 & 20 7.0 & 25 Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carisbad, Califomia March 5, 2005 Page 15 7.7 Surface Drainage Positive surface drainage should be provided adjacent to the structures to direct surface water away from the foundations and slabs toward suitable discharge facilities. Ponding of surface water should not be allowed adjacent to the structure or on flatwork. Landscaped areas should be designed with a minimum slope of two (2) percent. Desirable slopes in paved areas are at least one (1) percent. 7.8 Utilities The on-site soils are suitable for backfill of utility trenches from one foot above the top of the pipe to the surface, provided the material is free of organic matter and deleterious substances. It is anticipated that the natural soils will provide a firm foundation for site utilities. Any soft and/or unstable material encountered at the pipe invert should be removed and replaced with an adequate bedding material. The on-site soils are not considered suitable for bedding or shading of utilities. Therefore, we recommend that non-expansive granular soils with a Sand Equivalent (SE) greater than 30 as determined by ASTM Test Method D2419-91 be imported for that purpose. Trench backfill soils should be compacted to at least 90 percent of the maximum dry density as determined by ASTM Test Method Dl 557-00. 7.9 Soil Corrosivity Soluble sulfates and soil corrosivity tests were performed by EGL Inc. Test Laboratory, Santa Fe Springs, California on selected samples of soils encountered in the borings. The results are presented in Appendix C and summarized herein. The pH of the soils was 6.8, which is neutral. The soil sulfates content 0.006 percentage by weight, which is negligibly corrosive to concrete. Accordingly, Type I or II Portland cement can be used. The chloride content of the soil samples tested was 105 ppm, and the resistivity (saturated) of the soil tested 2,400 ohm-cm indicate the soils are corrosive to buried ferrous metals in contact with these soils. Therefore, corrosion mitigation measures are considered appropriate which may include the following: • All steel and wire concrete reinforcement should have at least three (3) inches of concrete cover where cast against soil, unformed. • Below-grade ferrous metals should be given a high-quality protective coating, such as 18-mil plastic tape, extruded polyethylene, coal-tar enamel, or Portland cement mortar. • Below-grade metals should be electrically insulated (isolated) from above-grade metals by means of dielectric fittings in ferrous utilities and/or exposed metal structures breaking grade. Converse Consultants M:\JOBFiLE\2005\32\05-123 DONAHUESCHRIBER\05-32123-01-GIR.DOC 1 Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carisbad, California March 5, 2005 Page 16 • If a more specific recommendations are needed a Corrosion Engineer should be contacted. 7.10 Plan Review, Observations and Testing As the final project plans and specifications are completed, they should be fon^/arded to Converse for review for conformance with the intent of these recommendations. All excavation and the placement and compaction of backfill should be performed under the observation of and testing by Converse. All structure backfill and excavations should be obsen/ed prior to placing the bedding material to verify that pipe bedding materials and any structures, are founded on satisfactory soils, and that the excavations are free of loose and disturbed materials. 8.0 CLOSURE This report has been prepared for the exclusive use of Donahue Schriber and their, consultants to assist in the design and construction of the proposed retail structures. Any reliance on this report by third parties shall be at third party's sole risk. Our sen/ices have been performed in accordance with applicable state and local ordinances, and generally accepted practices within our profession. Converse is not responsible or liable for any claims or damages associated with interpretation of available information provided by others. Site exploration identifies actual soil conditions only at those points where samples are taken, when they are taken. Data derived through sampling and analytical testing are extrapolated by Converse employees who render an opinion about the overall soil conditions. Actual conditions in areas not sampled may differ. In the event that changes to the property occur, or additional, relevant information about the property is brought to our attention, the recommendations contained in this report may not be valid unless these changes and additional relevant information are reviewed and the recommendations ofthis report are modified or verified in writing. Our findings and recommendations were obtained in accordance with generally accepted professional principles practiced in geotechnical engineering. We make no other warranty, either express or implied. Converse Consultants M:\JoBFiLE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOG Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carisbad, California March 5, 2005 Page 17 REFERENCES BLAKE, T. F., 2000, EQSEARCH, FRISKSP, Version 3.0, computer programs for performing deterministic and historical seismic hazard analysis. CALIFORNIA DIVISION OF MINES AND GEOLOGY (1994), Fault Activity Map of California and Adjacent Areas, DMG Geologic Data Map No. 6. CALIFORNIA BUILDING STANDARDS COMMISSION (2001), California Building Code (CBC). INTERNATIONAL CONFERENCE OF BUILDING OFFICIAL (1997), Uniform Building Code (UBC). NAVFAC (1986), Design Manual 7.02: Foundation and Earth Structures. STANDARD SPECIFICATIONS FOR PUBLIC WORKS CONSTRUCTION (2003), Joint Committee ofthe Southern California Chapter, American Public Works Association and Southern California Districts Associated General Contractors of California. UNITED STATES GEOLOGICAL SURVEY (USGS), 2001; Groundwater Levels for California. Converse Consultants M;\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC A P P E N D I X A APPENDIX A FIELD EXPLORATION Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carisbad, Califomia March 5, 2005 Page A-1 APPENDIXA FIELD EXPLORATION Our field investigation included a site reconnaissance of the property and a subsurface exploration program consisting of drilling test borings. During the site reconnaissance, the surface conditions were noted and the locations of the test borings were determined. The test borings were located by pacing with existing topography and boundary features, and should be considered accurate only to the degree implied by the method used. The test borings were advanced using a truck-mounted rig equipped with eight-inch diameter hollow-stem auger for soil sampling. A total of four (4) borings (BH-1 through BH-4)were drilled on March 25 and 28, 2005 to depths ranging from 2172 and 5172 feet. Two borings were drilled on each pad. Soils encountered in the borings were logged by our field engineer and geologist and classified in the field by visual examination in accordance with the Unified Soil Classification System. The field descriptions have been modified where appropriate to reflect laboratory test results. Relatively undisturbed ring samples and bulk samples of the subsurface soils were obtained at frequent intervals in the borings. The relatively undisturbed samples were obtained using a California Drive Sampler (2.4-inch inside diameter [I.D.], 3.0-inch outside diameter [O.D.]) lined with thin sample rings, and disturbed (bulk) samples were obtained using a split spoon sampler (178-inch I.D. and 2-inch O.D). Both sampler types are indicated in the "drive samples" column of the boring logs as presented in this appendix. Resistance and Standard Penetration Test (SPT) blow counts were obtained with the sampler by dropping a 140-pound automatic hammer through a 30-inch free fall. The sampler was driven 18 inches, and the number of blows were recorded for each six (6) inches of penetration. The blows per foot was recorded on the boring logs represent the accumulated number of blows required for the last 12 inches, or shorter distance as indicated when refusal was encountered. The Standard Penetration tests were performed in accordance with ASTM Standard Dl 586-84 test method. For a key to soil symbols and terminology used in the boring logs, refer to Drawing No. A-1, Unified Soil Classification and Key to Boring Log Symbols. For logs of the borings, see Drawing Nos. A-2 and A-5, Log of Boring. Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUESCHRIBER\05-32123-01-GIR.DOC APPENDIX B SUMMARY OF LABORATORY TEST RESULTS SOIL CLASSIFICATION CHART MAJOR DIVISIONS COARSE GRAINED SOILS MORE THAN 50% 01 ^MTERIAL IS LARGER THAN NO 200 SIEVE SIZE GRAVEL AND GRAVELLY SOILS MORE THAN 50% OF COARSE FRACTION RETAINED ON NO 4 SIEVE SAND AND SANDY SOILS MORE THAN 50% OF COARSE FRACTION PASSING ON NO. 4 SIEVE CLEAN GRAVELS (LITTLE OH NO FINES) l=-r \ o U GRAVELS WITH FINES (APPRECIABLE AMOUNT OF FINES) CLEAN SANDS ILITTLE OB NO FINES) SYMBOLS GRAPH SANDS WITH FINES (APPRECIABLE AMOUNT OF FINES) LETTER GW GP GM TYPICAL DESCRIPTIONS WELL-GRACED GRAVELS, jRAVEL - SANO MIXTURES. LITTLE OR NO FINES ^OOHLY-GRADED GRAVELS, GRAVEL • SAND MIXTURES, LITTLE OH NO FINES GC SW SP SM SC SILTY GRAVELS, GRAVEL - SANO - SILT MIXTURES CLAYEY GRAVELS. GRAVEL - SAND-CUVY MIXTURES WELL-GRADED SANDS. GRAVELLY SANOS, LITTLE OR NO FINES POORLY-GRADED SANOS, GRAVELLY SANO, LITTLE OR NO FINES StLTY SANOS, SANO - SILT MIXTURES CUYEY SANOS, SANO - CLAY MIXTURES ML INORGANIC SILTS AND VERV FINE SANOS, HOCK FLOUR, SILTY OR CLAYEY FINE SANOS OR CLAYEY SILTS WITH gi ir.UT PI tgTiriTv FINE GRAINED SOILS MORE THAN 50% OF MATERIAL IS SMALLER THAN NO. 200 SIEVE SIZE SILTS AND CLAYS LIQUID LIMITLESS THAN 50 CL INORGANIC CLAYS OF LOW/ TO MEDIUM PLASTICITY. GRAVELLY CLAYS. SANOY CLAYS, SILTY CUVYS, LEAN CLllS OL ORGANIC SILTS ANO ORGANIC SILTY CUYS OF LOW PLASTICITY SILTS AND CLAYS LIQUID UMIT GREATER THAN 50 MH INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE SANO OR SILTY SOILS CH INORGANIC CLAYS OF HIGH PLASTICITY OH ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTS HIGHLY ORGANIC SOILS PT PEAT HUMUS, SWAMP SOILS WITH HIGH ORGANIC CONTENTS NOTE: DUAL SYMBOLS ARE USEO TO INDICATE BORDERLINE SOIL CLASSIFICATIONS BORING LOG SYMBOLS • SAMPLE TYPE STANDARO PENETRATION TEST Split barrel sampler in accordance with ASTM 0-1586-84 Standard Test Method DRIVE SAMPLE 2.42" I D. sampler, driven with 140 Ib weight, 30 m. drop DRIVE SAMPLE No recovery BULK SAMPLE GROUNDWATER WHILE DRILLING GROUNDWATER AFTER DRILLING UBORATORY TESTING ABBREVIATIONS TEST TYPE STRENGTH (Results shown in Appendix B) Pocket Penetrometer Direct Shear P ds Direct Shear (singli point) ds- CLASSIFICATION Unconfined Compression Triaxial Compression UC tx Plasticity pi Vane Shear vs Grain Size Analysis ma vs Passing No. 200 Sieve wa Consolidation c Sand Equivalent se Collapse TasI col Expansion Index ei Resistance (R) Value r Compaction Curve max Chemical Anatysis ca Hydrometer h Electrical Resistivity •r UNIFIED SOIL CLASSIFICATION AND KEY TO BORING LOG SYMBOLS Converse Consultants Project Name Two Proposed Retail Structures 7190 Avenida Encinas Carlsbad, CA Project No. 05-32123-01 Drawing No. A-1 Log OT boring NO.BH-T Dates Drilled: 3/25/2005 Logged by: CKL Equipment: 8" HOLLOW STEM AUGER Driving Weight and Drop: 140 lbs/30 in Ground Surface Elevation (ft): 70 Depth to Water (ft): _ 21 feet Checked By: KN 20 - SUMMARY OF SUBSURFACE CONDITIONS This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered. FILL: CLAYEY SAND (SC): fine- to medium-grained, brown. NATIVE: CLAYEY SAND(SC): fine- to medium-grained, light gray. - gray brown CLAY (CL): light gray. SILTY SAND (SM): fine-grained, gray. fine- to medium-grained End of boring at 26.5 feet. Groundwater encountered at 21 feet at the time of drilling. Boring backfilled with bentonite chips and grout. Project Name Converse Consultants ^rgrATirES'^"'^*""' Carlsbad, CA SAMPLES o o CO 85 68 65 48 50-6" 50-6" (50-6"; UJ cr: I- O as 15 14 16 18 15 Project No, 05-32123-01 10 124 111 117 115 111 108 Q CL Drawing No. A-2 Log of Boring No.BH-2 Dates Drilled: 3/25/2005 Logged by: CKL Checked By: Equipment: 8''HOLLOW STEM AUGER Driving Weight and Drop: 140 lbs/ 30 in Ground Surface Elevation (ft): 70 Depth to Water (ft): 20 feet KN SUMMARY OF SUBSURFACE CONDITIONS This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered. - 25 - 30 4 FILL: SILTY SAND (SM): fine- to medium-grained, trace clay, gray brown. NATIVE: SILTY SAND (SM): fine- to medium-grained, gray, - trace clay CLAYEY SAND(SC): fine- to medium-grained, gray brown. CLAY (CL): light gray. - trace fine- grained sand CLAYEY SAND (SC): fine-grained, light gray. • fine- to medium-grained Project Name Converse Consultants ^rgrArirES^*"*^'"^ Project No. 05-32123-01 Drawing No. A-3a Carlsbad, CA Log of Boring No.BH-2 Dates Drilled: 3/25/2005 Logged by: CKL Equipment: 8" HOLLOW STEM AUGER Driving Weight and Drop: 140 lbs / 30 in Ground Surface Elevation (ft): 70 Depth to Water (ft): 20.feet Checked By: KN Q. (U Q Q. SUMMARY OF SUBSURFACE CONDITIONS This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered. SAMPLES UJ > a: D Q CQ o o u. O _j CO UJ H-W O H Z D ><:x as a CL - 40 45 - 50 CLAYEY SAND (SC): fine-grained, light gray. fine- to medium-grained fine- grained - fine- to coarse-grained End of boring at 51.5 feet. Groundwater encountered at 20 feet at the time of drilling. Boring backfilled with bentonite chips and grout. (50-6") 50-6" (50-6") 50-6" 15 16 107 89 Converse Consultants Project Name Two Proposed Retail Structures 7190 Avenida Encinas Carlsbad, CA Project No. 05-32123-01 Drawing No. A-3b Log of Boring No.BH-3 Dates Drilled: 3/28/2005 Equipment: 8" HOLLOW STEM AUGER Ground Surface Elevation (ft): 70 Logged by: CKL Driving Weight and Drop: 140 lbs/30 in Depth to Water (ft):_ _ 21 feet Checked By: KN Q. 0) Q r 5 - 15 10 - 20 25 - 30 SUMMARY OF SUBSURFACE CONDITIONS This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location ofthe boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered. FILL : SAND (SP): fine-grained, reddish brown. NATIVE: CLAYEY SAND (SC): fine- to medium-grained, yellowish brown. medium- to coarse-grained fine- to medium-grained, orange brown SILTY SAND (SM): fine-grained, tan gray. - yellowish brown Converse Consultants JraoSra^ESL''"^*"" Project Name Two Proposed 7190 Avenida Carlsbad, CA SAMPLES; O O LL cn O _i ca ! UJ IT I- O 45 60 85-11" 50-6" (45) 50-6" (50-5") 50-5" 2 >-<^^ Q S 11 14 15 15 19 Project No. 05-32123-01 10 118 111 108 108 105 105 114 106 9 a Drawing No. A-4a Dates Drilled: 3/28/2005 Equipment: 8" HOLLOW STEM AUGER Ground Surface Elevation (ft): 70 Log of Boring No.BH-3 Logged by: CKL Driving Weight and Drop: 140 lbs/30 in Depth to Water (ft): 21 feet Checked By: KN Q. 01 a y a 03 O) (33 SUMMARY OF SUBSURFACE CONDITIONS This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered. - 40 - 45 - 50 SILTY SAND (SM): fine-grained, yellowish brown. tan gray SAMPLES! 1-i O I o 1 u. CO OQ SAND (SP): fine-grained, tan gray. End of boring at 51.5 feet. Groundwater encountered at 21 feet at the time of drilling. Boring backfilled with bentonite chips and grout. Converse Consultants (50-6") LU 01 D H CD 2 aS 50-6" (50-6") 50-3" 9 Q. Project Name Two Proposed Retail Structures 7190 Avenida Encinas Carlsbad, CA Project No, 05-32123-01 Drawing No. A-4b Dates Drilled: 3/25/2005 Equipment: 8" HOLLOW STEM AUGER Ground Surface Elevation (ft): 70 Log of Boring No.BH-4 Logged by: CKL Driving Weight and Drop: 140 lbs/30 in Depth to Water (ft): 21feet Checked By: KN Q. 0) Q o x: Q. ra cn 63 SUMMARY OF SUBSURFACE CONDITIONS This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the bohng and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered. SAMPLES o o u. cn CQ LU H cn O aS 9 CL - 10 15 20 25 30 FILL: SAND (SP): fine- to medium-grained, orange brown. NATIVE: SAND (SP): fine- to medium-grained, tan brown. orange brown jr - medium- to coarse-grained CLAYEY SAND (SC): fine- to medium-grained, brown. fine- grained 70 83 35 40 (55) 80 (50-6") 50-6" 14 111 104 96 100 101 Project Name Converse Consultants JraoATira^ESas'^^'^'"^^ Project No. 05-32123-01 Drawing No. A-5a Carlsbad, CA Dates Drilled: 3/25/2005 Equipment: 8" HOLLOW STEM AUGER Ground Surface Elevation (ft): 70 L-uy Ul Duniiy MO.Dn-<t Logged by: CKL Driving Weight and Drop: 140 lbs/ 30 in Depth to Water (ft): 21 feet Checked By: KN x: a. (S3 a SUMMARY OF SUBSURFACE CONDITIONS This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling Subsurface conditions may differ at other locations and may chanqe at this location with the passage of time. The data presented is a simplification of actual conditions encountered. y x: a ro o) 5.3 CLAYEY SAND(SC): fine- to medium-grained, brown. End of boring at 36.5 feet. Groundwater encountered at 20 feet at the time of drilling. Boring backfilled with bentonite chips and grout. Converse Consultants Project Name Two Proposed Retail Structures 7190 Avenida Encinas Carlsbad, CA Project No. 05-32123-01 Drawing No. A-5b A P P E N D I X B Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carlsbad, Califomia March 5, 2005 Page B-1 APPENDIX B SUMMARY OF LABORATORY TEST RESULTS Tests were conducted in our laboratory on representative soil samples for the purpose of classification and evaluation of their relevant physical characteristics and engineering properties. The amount and selection of tests were based on the geotechnical requirements of the project. Test results are presented herein and on the boring logs (see Appendix A, Field Exploration). The following is a summary of the various laboratory tests conducted forthis project. Moisture Content and Dry Density Results of moisture content and dry density tests, performed on relatively undisturbed ring samples were used to aid in the classification of the soils and to provide quantitative measure of the in-situ dry density. Data obtained from this test provides qualitative information on strength and compressibility characteristics of site soils. For test results, see the boring logs (Appendix A, Field Exploration). Sieve Analysis To aid in classification of the soils, mechanical grain-size analysis were performed on two (2) representative samples. Testing was performed in accordance with the ASTM Standard D422 method. For test results, see Drawing No. B-1, Grain Size Distribution Results. Amounts of Material in Soils Finer Than the No. 200 Sieve Five (5) selected samples were tested in accordance with the ASTM Standard D1140- 92 test method to determine the amount of material finer than U.S. Standard Sieve No. 200. This information is summarized below: Table No. B-1, Percent Finer than #200 Sieve Results Boring No. Depth (ft) Soil Classification Percent Finer Than No. 200 Sieve {%) *BH-1 7.5 CLAYEY SAND (SC) 29 BH-1 15 SILTY SAND (SM) 24 BH-2 20 CLAYEY SAND (SC) 15 BH-2 35 CLAYEY SAND (SC) 22 BH-3 20 CLAYEY SAND (SC) 28 BH-4 5 SAND (SP) 5 *BH-4 25 CLAYEY SAND (SC) 19 Converse Consultants M:\JOBFiLE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carlsbad, California March 5, 2005 Page B-2 Expansion Index Test One (1) representative bulk sample was tested to evaluate the expansion potential of material encountered at the site. The test was conducted in accordance with UBC/CBC Standard. For test results, see Table No. B-2 below: Table No. S-2, Summary of Expansion Index Test Results Boring No. Depth (feet) Soil Description Expansion Index Expansion Potential BH-1 0-5 CLAYEY SAND (SC) 7 Very Low Direct Shear Tests Three (3) direct shear tests were performed on undisturbed samples and remolded sample to 90 percent relative compaction, at soaked moisture conditions. Each sample, contained in three brass sampler rings, was placed, one at a time, directly into the test apparatus and subjected to a range of normal loads appropriate for the anticipated conditions. The sample was then sheared at a constant strain rate of 0.01 inch/minute. Shear deformation was recorded until a maximum of about 0.25-inch shear displacement was achieved. Peak strength was selected from the shear-stress deformation data and plotted to determine the shear strength parameters. For test data, including sample density and moisture content, see Drawing No. B-3 through B-5, Direct Shear Test Results and Table No. B-3 below: Table No. B-3, Summary of Direct Shear Test Results Boring No. Depth (feet) Soli Classificatton Peak Strength Parameters Boring No. Depth (feet) Soli Classificatton Friction Angle (degrees) Cotiesion (psf) BH-r 0-5 CLAYEY SAND (SC) 30 200 BH-3* 0-5 SAND (SP) 32 0 BH-4 * n 1-1 t 4. _ 7.5 SAND (SP) 36 0 Consolidation Test Data obtained from this test, performed on two (2) relatively undisturbed soil samples, were used to evaluate the settlement characteristics of the on-site soils under load! Preparation for this test involved trimming the sample, placing it in a one-inch-high brass ring, and loading it into the test apparatus, which contained porous stones to Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carlsbad, Califomia March 5, 2005 Page B-3 accommodate drainage during testing. The sample was tested at field moisture and submerged conditions. Normal axial loads were applied to one end ofthe sample through the porous stones, and the resulting deflections were recorded at various times. The load was increased after the sample reached a reasonable state of equilibrium. Normal loads were applied at a constant load-increment ratio, successive loads being generally twice the preceding load. For test results, including sample density and moisture content, see Drawing No. B-6 and B-7, and Consolidation Test Results. Soil Corrosivity One (1) representative soil sample was tested to determine minimum electrical resistivity, pH, and chemical content, including soluble sulfate and chloride concentrations. The purpose of these tests is to determine the corrosion potential of site soils when placed in contact with common construction materials. These tests were performed by EGL Inc. Test Laboratory, Santa Fe Springs, California. For test results, see below. Table No. B-4, Soil Corrosivity Test Resu ts Boring Nc/Depth pH Chloride (ppm) Sulfate (% by weight) Min. Resistivity (as-received) (ohm-cm) BH-4 / 0 - 5' 6.81 105 0.006 2,400 Sample Storage Soil samples presently stored in our laboratory will be discarded 30 days after the date of this report, unless this office receives a specific request and a fee to retain the samples for a longer period. Converse Consultants M:\JOBFILE\2005\32\05-123 DONAHUE SCHRIBER\05-321 23-01-GIR.DOC U.S. SIEVE OPENING IN INCHES u,s, SIEVE NUMBERS HYDROMETER 6 \ 3 ^15 ' 3/4 ^^^3/8 ^ A ^ 8^° 14^^ 20 ^° 40 ^0 60 140 2°° 1 0,1 GRAIN SIZE IN MILLIMETERS COBBLES GRAVEL SAND 0.01 0.001 SILT OR CLAY Boring No. Depth (ft) Description LL PL PI Cc Cu • BH-1 7.5 CLAYEY SAND (SC) CD BH-4 25 CLAYEY SAND (SC) Boring No. Depth (ft) D100 D60 D30 DIO %Gravel %Sand %Si t 1 °A )Clav • BH-1 7.5 4.76 0.236 0.081 0.0 71.0 29.0 IZl BH-4 25 4.76 0.269 0.134 0.0 81.0 19.0 GRAIN SIZE DISTRIBUTION RESULTS Converse Consultants Project Name Two Proposed Retail Structures 7190 Avenida Encinas Carlsbad, CA Project No. 05-32123-01 Drawing No. B-1 >- OT Z LU Q >- o 135 130 ^ 125 120 115 110 105 100 95 90 ) \\\/ Uuivub Ul 100% Sail for Specific Gravity E .2.65 alien qual to: Vv WATER CONTENT, % SYMBOL SAMPLE NO, DEPTH (ft) DESCRIPTION ASTM TEST METHOD OPTIMUM WATER, % MAXIMUM DRY DENSITY, pcf • BH-3 0-5 SAND (SP) D1557 Method A 12 124 Zl BH-1 0-5 CLAYEY SAND (SC) D1557 Method A 8 133 - MOISTURE-DENSITY RELATIONSHIP RESULTS ® Project Name Proiect No ^ li. . Two Proposed Retail structures riujcuiiNu. Converse Consultants 7190 Avenida Encinas 05-32123-01 Carlsbad, CA Drawing No. B-2 4,000 3,500 3,000 i 2,500 X I-o z UJ OT a: < ill X OT 2,000 1,500 1,000 500 1,000 2,000 NORMAL PRESSURE, psf 3,000 4,000 SAMPLE NO. BH-1 DEPTH (ft) 0-S DESCRIPTION CLAYEY SAND (SC) COHESION (psf) 200 FRICTION ANGLE (degrees): 30 MOISTURE CONTENT (%) : 14 DRY DENSITY (pcf) 120 NOTE: SAMPLES REMOLDED TO 90% RELATIVE COMPACTION DIRECT SHEAR TEST RESULTS Converse Consultants Project Name Two Proposed Retail Structures 7190 Avenida Encinas Carlsbad, CA Project No. 05-32123-01 Drawing No. B-3 4,000 3,500 3,000 i 2,500 x" o z LU a. Ul a. < UJ x w 2,000 1,500 1,000 1,000 2,000 NORMAL PRESSURE, psf 3,000 4,000 SAMPLE NO. BH-3 DEPTH (ft) 0-5 DESCRIPTION SAND (SP) COHESION (psf) 300 FRICTION ANGLE (degrees): 28 MOISTURE CONTENT (%) : 10 DRY DENSITY (pcf) 112 NOTE: SAMPLES REMOLDED TO 90% RELATIVE COMPACTION DIRECT SHEAR TEST RESULTS Converse Consultants Project Name Two Proposed Retail Structures 7190 Avenida Encinas Carlsbad, CA Project No. Drawing No. 05-32123-01 B-4 4,000 3,500 3,000 I 2,500 o z Ul ^ 2,000 X OT 1,500 1,000 500 1,000 2,000 NORMAL PRESSURE, psf 3,000 4,000 SAMPLE NO. BH-4 DEPTH (ft) 7.5 DESCRIPTION SAND (SP) COHESION (psf) 0 FRICTION ANGLE (degrees): 36 MOISTURE CONTENT (%) : 5 DRY DENSITY (pcf) 96 NOTE: PEAK STRENGTH DIRECT SHEAR TEST RESULTS Converse Consultants Project Name Two Proposed Retail Structures 7190 Avenida Encinas Carlsbad, CA Project No. 05-32123-01 Drawing No. B-5 I I I I I I I I i I I : I 1 z h- OT STRESS, ksf SAMPLE NO. BH-1 DEPTH (ft) 5 DESCRIPTION : CLAYEY SAND (SC) SPECIFIC GRAVITY : 2.65 MOISTURE CONTENT (%) DRY DENSITY (pcf) PERCENT SATURATION VOID RATIO INITIAL 15 FINAL 17 111 115 82 100 0.467 0.416 NOTE: SOLID CIRCLE INDICATES READING AFTER ADDITION OF WATER. CONSOLIDATION TEST RESULTS 1^ Project Name Converse Consultants ?r9°oSS:'En:SL'*"'^^ Carlsbad, CA Project No. 05-32123-01 Drawing No. B-6 I X OT STRESS, ksf 100 SAMPLE NO. BH-3 DEPTH (ft) 7.5 DESCRIPTION : CLAYEY SAND (SC) SPECIFIC GRAVITY : 2.65 MOISTURE CONTENT(%) DRY DENSITY (pcf) PERCENT SATURATION VOID RATIO INITIAL 9 108 45 0.510 FINAL 16 112 90 0.456 NOTE: SOLID CIRCLE INDICATES READING AFTER ADDITION OF WATER. , CONSOLIDATION TEST RESULTS Wi 1^ Project Name Converse Consultants J^rA^rEnS'''"'"™' Carlsbad, CA Project No. Drawing No. 05-32123-01 B-7 I A P P E N 0 / f f I X C APPENDIX C EARTHWORK SPECIFICATIONS ^''tC/F/CAT/o/vs 3bor o, ^^^^'^ 5, 2005 Page C-1 ExcavaKoos Preparation of p • The design aoH ^-'^^^^^^d in tH- s^bsurfa ° ^^'^^ C°nsu/tanf. ^^^°^'^ed. o.3.„,„3 ^-___^-tface an. 2. 3. 3. -t.t\-*ns to ,e "^FS ' subor.=H« • ^^"erneath o/, ^®f^oved anw feet hpw„ ^ S'x re) /of® a" area<. f structure s/ahcf '^^o^Pacted . •-•~wnsu«a„,s — I 1 'I I 'I I 2. an°ctXt^ -ay , '"'^'^ ^.e ap^ ^'f-"? 5. 4,, "'Pac(eca;°®P/aced„„ '^'"'""al of ,H ^"'^'^ e, -S-^eee:::;---^^^^^^^ ^'^«-te,n,., l^X^^' ^^"'^ - appro,,, , ^sec^ 3^'^^/ eng/^^ on~site earth ^eefeT^^^^a/ /'"""'^et' W ^"=«''aoeoos /„ """"'"a/ ptv° ^'rZ^:^^^^^^^^^^ to ,0 "^^""^"^^o • more 'abot^f «''a« fta.„ , ' "^"^"t of „ '•--::^;r^~^^ -ent . Cf. 3. Geotechnical Investigation Report Two Retail Stores - Pad 4 and Pad 6 7190 Avenida Encinas Carlsbad, California March 5, 2005 Page C-4 shall be moisture conditioned to within two (2) percent, and clayey soils to at least two (2) percent above, optimum moisture content. 5. Fill exceeding five (5) feet in height shall not be placed on native slopes that are steeper than 5 to 1 (horizontal to vertical). Where native slopes are steeper than 5 to 1, and the height of the fill is greater than five (5) feet, the fill shall be benched Into competent materials. The height and width of the benches shall be at least two (2) feet. 6. Representative samples of materials being used as compacted fill will be analyzed in the laboratory by the geotechnical engineer to obtain information on their physical properties. Maximum laboratory density of each soil type used in the compacted fill will be determined by the ASTM D1557-00 compaction method. 7. Fill materials shall not be placed, spread or compacted during unfavorable weather conditions. When site grading is interrupted by heavy rain, filling operations shall not resume until the geotechnical engineer approves the moisture and density conditions ofthe previously placed fill. 8. It shall be the grading contractor's obligation to take all measures deemed necessary during grading to provide erosion control devices In order to protect slope areas and adjacent properties from storm damage and flood hazard originating on this project. It shall be the contractor's responsibility to maintain slopes in their as-graded form until all slopes are in satisfactory compliance with job specifications, all berms have been properly constructed, and all associated drainage devices meet the requirements ofthe civil engineer. Cf .8 Observation and Testing 1. During the progress of grading, the geotechnical engineer will provide observation ofthe fill placement operations. 2. Field density tests will be made during grading to provide an opinion on the degree of compaction being obtained by the contractor. Where compaction less than specified herein is indicated, additional compactive effort with adjustment of the moisture content shall be made as necessary until the required degree of compaction is obtained. 3. A sufficient number of field density tests will be performed to provide an opinion to the degree of compaction achieved. In general, density tests will be performed on each one-foot lift of fill, but not less than one for each 500 cubic yards of fill placed. Converse Consultants M:\JOBFiLE\2005\32\05-123 DONAHUE SCHRIBER\05-32123-01-GIR.DOC