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HomeMy WebLinkAboutCDP 05-19; TOYOTA CARLSBAD RENOVATION AND ADDITION; GEOTECHNICAL ENGINEERING INVESTIGATION;o o < I I- J. . t / I ) ; Geotechnical Engineering Investigation sedfToyota CarisbadyRenovation and Addition Develoi: w«. - *^*gra^tJ30 Avenida Encinas Carisbad, California I 8400- I-- V- -8600 il - ( E isr G IlSr E E RIN G SQILS 1.^ \ '3! n0 0-' / is / t i id m \. ,60° • C ONS U43AT^T'S 4: Geotechnical Engineering Investigation Proposed Toyota Carlsbad Renovation and Addition Development 6020-6030 Avenida Encinas Carlsbad, California Prepared For: Toyota Carlsbad 6030 Avenida Encinas #220 Carlsbad, California 92008 Attn.: Ms. Judith Jones Project Number 12040-05 April 4, 2005 TABLE OF CONTENTS Section Page 1.0 Project Description 2 2.0 Site Description 2 3.0 Site Exploration 2 4.0 Laboratory Tests 3 4.1 Field Moisture Content 4 4.2 Maximum Density Test 4 4.3 Expansion Index Tests 4 4.4 Corrosion Design Criteria 4 4.5 Direct Shear Tests 4 4.6 Consolidation Tests 4 5.0 Seismicity Evaluation 5 6.0 Liquefaction Evaluation 6 7.0 Conclusions and Recommendations 7 7.1 Site Grading Recommendations 7 7.1.1 Removal and Recompaction Recommendations 8 7.1.2 Fill Blanl<et Recommendations 9 7.2 Shrinkage and Subsidence 9 7.3 Temporary Excavations 10 7.4 Foundation Design 10 7.5 Settlement Analysis 11 7.6 Lateral Resistance 11 7.7 Retaining Wail Design Parameters 11 7.8 Slab Design 12 7.9 Pavement Section Design 13 7.10 Utility Trencii and Excavation Backfili 14 7.11 Corrosion Design Criteria 14 8.0 Closure 15 NorCal Engineermg Soils and Geotechnical Consultants 10641 Humbolt Street Los Alamitos, CA 90720 (562) 799-9469 Fax (562) 799-9459 April 4, 2005 Project Number 12040-05 Toyota Carlsbad 6030 Avenida Encinas #220 Carlsbad, California 92008 Attn.: Ms. Judith Jones RE: Geotechnical Engineering Investigation - Proposed Toyota Carlsbad Renovation and Addition Development - Located at 6020- 6030 Avenida Encinas, in the City of Carlsbad, California Dear Ms. Jones: Pursuant to your request, this firm has performed a Geotechnical Engineering Investigation in accordance with your authorization. The purpose of this investigation is to evaluate the subsurface conditions of the subject site and to provide recommendations for the proposed automobile service development. The scope of work included the following: 1) site reconnaissance; 2) subsurface geotechnical exploration and sampling; 3) laboratory testing; 4) engineering analysis of field and laboratory data; 5) and preparation of a geotechnical engineering report. It is the opinion ofthis firm that the proposed development is feasible from a geotechnical standpoint provided that the recommendations presented in this report are followed in the design and construction ofthe project. April 4, 2005 Project Number 12040-05 Page 2 1.0 Project Description It is proposed to renovate and construct new additions to the rear existing building at the subject property, it is assumed that the proposed grading for the development will include minor cut and fill procedures. Final building plans shall be reviewed by this firm prior to submittal for city approval to determine the need for any additional study and revised recommendations pertinent to the proposed development, if necessary. 2.0 Site Description The subject project is located within the 6000 block and north side of Encinas Drive, southerly of Palomar Airport Road, in the City of Carlsbad. The rectangular-shaped parcel is elongated in an east to west direction with topography of the relatively level property descending gradually from front to rear with a total relief of a few feet. The property currently contains three existing structures, two of which will be converted to a service center and the front building will remain as a paint and body center. The remainder of the site contains asphaltic concrete driveway, grass areas and concrete drainage swales. 3.0 Site Exploration The investigation consisted of the placement of four (4) subsurface exploratory borings by a truckmounted hollowstem auger and hand auger to a depth of 3.5 and 50 feet below current ground elevations. The explorations were visually classified and logged by a field engineer with locations of the subsurface explorations shown on the attached Site Plan. The exploratory excavations revealed the existing earth materials to consist of a disturbed top soil/fill and natural soil. A detailed description of the subsurface conditions are listed on the excavation logs in Appendix A. NorCal Engineering April 4, 2005 Project Number 12040-05 Page 3 Existing Pavement: A pavement section consist of four inches of asphaltic concrete over 12 inches of base over 8 inches of rock was encountered in Boring B-4. Seeping water was found at 8 inches and continued to seep throughout the exploration. Fill: A fill/disturbed soil classifying as a fine grained, silty SAND was encountered across the site and ranged in depth from 1.5 to 9 feet. These soils were noted to be medium dense and moist to very moist. The deeper fill soils (9 feet) appear to be an isolated area and could be the result of a previous tank backfill. Natural: An undisturbed alluvium soil classifying as a silty sandy CLAY to clayey SAND was encountered beneath the upper surface soils. These native soils were observed to be firm to stiff to dense and moist to very moist. A SANDSTONE bedrock was encountered in Boring B-1 at a depth of 26 feet which was dense to very dense. The overall engineering characteristics of the earth material were relatively uniform with each excavation. No groundwater was encountered to the depth of our exploratory excavations and no caving occurred in the deeper cohesionless soils. 4.0 Laboratorv Tests Relatively undisturbed samples of the subsurface soils were obtained to perform laboratory testing and analysis for direct shear, consolidation tests, and to determine in-place moisture/densities. These relatively undisturbed ring samples were obtained by driving a thin-walled steel sampler lined with one inch long brass rings with an inside diameter of 2.42 inches into the undisturbed soils. Standard penetration tests were obtained by driving a steel sampler lined with six-inch long brass rings with an inside diameter of 1.5 inches into the soils. This standard penetrometer sampler was driven a total of eighteen inches with blow counts tallied every six inches. Blow count data is given on the Boring Logs in Appendix A. NorCal Engineering April 4, 2005 Project Number 12040-05 Page 4 Bulk bag samples were obtained in the upper soils for expansion index tests and maximum density tests. Wall loadings on the order of 4,000 Ibs./lin.ft. and maximum compression loads on the order of 100 kips were utilized for testing and design purposes. All test results are included in Appendix B, unless othenA/ise noted. 4.1 Field moisture content (ASTM:D 2216) and the dry density of the ring samples were determined in the laboratory. This data is listed on the logs of explorations. 4.2 Maximum density tests (ASTM: D-1557-00) were performed on typical samples of the upper soils. Results of these tests are shown on Table I. 4.3 Expansion index tests in accordance with the Uniform Building Code Standard No. 18-2 were performed on remolded samples of the upper soils. Results of these tests are provided on Table II. 4.4 Corrosion tests consisting of sulfate, pH, resistivity and chloride analysis to determine potential corrosive effects of soils on concrete and underground utilities were performed in the laboratory. Test results are provided on Table 111. 4.5 Direct shear tests (ASTM: D-3080) were performed on undisturbed and disturbed samples of the subsurface soils. The test is performed under saturated conditions at loads of 500 Ibs./sq.ft., 1,000 Ibs./sq.ft., and 2,000 Ibs./sq.ft. with results shown on Plate A. 4.6 Consolidation tests (ASTM: D-2435) were performed on undisturbed samples to determine the differential and total settlement which may be anticipated based upon the proposed loads. Water was added to the samples at a surcharge of one KSF and the settlement curves are plotted on Plate B. NorCal Engineering April 4, 2005 Project Number 12040-05 Page 5 5.0 Seismicitv Evaluation The northeast corner of the site is within the Alquist Priolo Special Studies Zone and the potential for damage due to direct fault rupture should be considered. The site is located in an area of high regional seismicity and a maximum credible horizontal ground acceleration of 0.45g may occur from a Magnitude 6.9 earthquake along the Rose Canyon fault zone. Ground shaking originating from earthquakes along other active faults in the region is expected to induce lower horizontal accelerations due to smaller anticipated earthquakes and/or greater distances to other faults. The following earthquake design parameters are based upon the 1997 Uniform Building Code (UBC) for a Seismic Zone 4 with a Z factor of 0.40 and a Soil Profile Type of SD, a stiff soil profile. 1997 UBC Seismic Desiqn Parameters Distance from Site (Rose Canyon Fault) 6 km Seismic Source Type B Seismic Coefficient = Ca (Table 16-Q) (0.44) Na Seismic Coefficient = Cv (Table 16-R) (0.64) K Near-Source Factor Na (Table 16-S) 1.0 Near-Source Factor N^ (Table 16-T) 1.16 Any building proposed within the Special Studies Zone will require to be assessed by an Engineering Geologist to determine the presence of an active fault and to designate and further define any building setback zone. The building setback zone may not be utilized for structures for human occupancy. NorCal Engineering April 4, 2005 Project Number 12040-05 Page 6 6.0 Liquefaction Evaluation The site is expected to experience ground shaking and earthquake activity that is typical of Southern California area. It is during severe ground shaking that loose, granular soils below the groundwater table can liquefy. A review of the exploratory boring log and the laboratory test results on selected soil samples obtained indicate the following soil classifications, field blowcounts and amounts of fines passing through the No. 200 sieve. Field Blowcount and Gradation Data Blowcounts Relative % Passing Location Classification (blows/ft) Densitv No. 200 Sieve B-1 @5' CL 4 Firm 62 B-1 @ 10' CL 11 Firm 49 B-1 @ 15' CL 12 Firm 53 B-1 @ 20' SM 28 Dense 14 B-1 @ 25' SM 31 Dense 46 B-1 @ 30' SP >50 Very Dense 29 B-1 @ 35' SP >50 Very Dense 21 B-1 @ 40' SM >50 Very Dense 17 B-1 @ 45' SM 11 Very Dense 19 B-1 @ 50' SM 4 Very Dense 20 • No groundwater encountered to a depth of 50 feet. Our analysis indicates the potential for liquefaction at this site is considered to be low, due to the very dense granular soils and bedrock. Seismic-induced settlements would be less than one inch and should occur rather uniformly across the site. Differential settiements from a nearby magnitude 6.9 earthquake would be one-half inch over a 100 feet (horizontal) distance in the building pad area. Thus, the design of the proposed construction in conformance with the latest Building Code provisions for earthquake design is expected to provide mitigation of ground shaking hazards that are typical to Southern California. NorCal Engineering April 4, 2005 Project Number 12040-05 Page 7 7.0 Conclusions and Recommendations Based upon our evaluations, the proposed development is acceptable from a geotechnical engineering standpoint. By following the recommendations and guidelines set forth in our report, the structures will be safe from excessive settlements under the anticipated design loadings and conditions. The proposed development shall meet all requirements of the City Building Ordinance and will not impose any adverse effect on existing adjacent structures. The following recommendations are based upon geotechnical conditions encountered in our field investigation and laboratory data. Therefore, these surface and subsurface conditions could vary across the site. Variations in these conditions may not become evident until the commencement of grading operations and any unusual conditions which may be encountered in the course of the project development may require the need for additional study and revised recommendations. It is recommended that site inspections be performed by a representative of this firm during all grading and construction of the development to verify the findings and recommendations documented in this report. The following sections present a discussion of geotechnical related requirements for specific design recommendations of different aspects of the project. 7.1 Site Gradinq Recommendations Any vegetation shall be removed and hauled from proposed grading areas prior to the start of grading operations. Existing vegetation shall not be mixed or disced into the soils. Any removed soils may be reutilized as compacted fill once any deleterious material or oversized materials (in excess of eight inches) is removed. Grading operations shali be performed in accordance with the attached "Specifications for Placement of Compacted Fill'. NorCal Engineering April 4, 2005 Project Number 12040-05 Page 8 7.1.1 Removal and Recompaction Recommendations All upper fill/disturbed soils (about 1.5 to 9 feet) shall be removed to competent native material, the exposed surface scarified to a depth of six inches, brought to within 2% of optimum moisture content and compacted to a minimum of 90% of the laboratory standard (ASTM: D-1557-00) prior to placement of any additional compacted fill soils, foundations, slabs-on-grade and pavement. Grading shall extend a minimum of five horizontal feet outside the edges of foundations or equidistant to the depth of fill placed, whichever is greater. Aeration of the soils with high moisture contents will be necessary and based upon the water noted on Boring B-4 and the 8 inch rock layer it will probably be necessary to stabilize some ofthe areas prior to the placement of any fill soils. It is possible that isolated areas of undiscovered fill, not described in this report are present on site. If found, these areas should be treated as discussed earlier. A diligent search shall also be conducted during grading operations in an effort to uncover any underground structures, irrigation or utility lines. If encountered, these structures and lines shall be either removed or properly abandoned prior to the proposed construction. Any imported fill material should be preferably soil similar to the upper soils encountered at the subject site. All soils shall be approved by this firm prior to importing at the site and will be subjected to additional laboratory testing to assure concurrence with the recommendations stated in this report. Care should be taken to provide or maintain adequate lateral support for all adjacent improvements and structures at all times during the grading operations and construction phase. Adequate drainage away from the structures, pavement and slopes should be provided at all times. NorCal Engineering April 4, 2005 Project Number 12040-05 Page 9 If placement of slabs-on-grade and pavement is not completed immediately upon completion of grading operations, additional testing and grading ofthe areas may be necessary prior to continuation of construction operations. Ukewise, if adverse weather conditions occur which may damage the subgrade soils, additional assessment by the geotechnical engineer as to the suitability of the supporting soils may be needed. 7.1.2 Fill Blani<et Recommendations Due to the potential for differential settiement of foundations placed on compacted fill and the medium dense native materials, it is recommended that all foundations be underlain by a uniform compacted fill blanket at least two feet in thickness. This fill blanket shall extend a minimum of five horizontal feet outside the edges of foundations or equidistant to the depth of fill placed, whichever is greater. 7.2 Shrinl<aqe and Subsidence Results of our in-place density tests reveal that the soil shrinkage will be on the order of 8 to 18% due to excavation and recompaction, based upon the assumption that the fill is compacted to 92% of the maximum dry density per ASTM standards. Subsidence should be 0.2 feet due to earthwork operations. The volume change does not include any allowance for vegetation or organic stripping, removal of subsurface improvements or topographic approximations. Although these values are only approximate, they represent our best estimate of lost yardage, which will likely occur during grading. If more accurate shrinkage and subsidence factors are needed, it is recommended that field testing using the actual equipment and grading techniques should be conducted. NorCal Engineering April 4, 2005 Project Number 12040-05 Page 10 7.3 Temporarv Excavations Temporary unsurcharged excavations in the existing site materials less than 4 feet high may be made at a vertical gradient unless cohesionless soils are encountered. Temporary unsurcharged excavations from 4 to 6 feet high may be trimmed at a 1 to 1 (horizontal to vertical) gradient. In areas where soils with littie or no binder are encountered, where adverse geological conditions are exposed, or where excavations are adjacent to existing structures, shoring, slot- cutting, or flatter excavations may be required. The temporary cut slope gradients given do not preclude local raveling and sloughing. All excavations shall be made in accordance with the requirements of CAL-OSHA and other public agencies having jurisdiction. Care should be taken to provide or maintain adequate lateral support for all adjacent improvements and structures at all times during the grading operations and construction phase. 7.4 Foundation Desiqn All new foundations may be designed utilizing the following an allowable soil bearing capacities for an embedded depth of 24 inches into approved fill materials with the corresponding widths: Allowable Soil Bearing Capacitv (psf) Continuous Isolated Width (ft) Foundation Foundation 1 5 1800 2300 2.0 1850 2350 4 0 2050 2550 6 0 2250 2700 NorCal Engineering April 4, 2005 Project Number 12040-05 Page 11 The bearing value may be increased by 500 psf for each additional foot of depth in excess of the 18-inch minimum depth, up to a maximum of 4,000 psf. A one third increase may be used when considering short term loading and seismic forces. Any foundations located along the property lines or where lateral overexcavation is not possible may utilize a safe bearing capacity of 1,250 psf. A representative of this firm shall inspect all foundation excavations prior to pouring concrete. All foundations shall be reinforced with a minimum of one No. 4 bar, top and boti:om. 7.5 Settiement Analysis Resultant pressure curves for the consolidation tests are shown on Plate B. Computations utilizing these curves and the recommended safe bearing capacities reveal that the foundations will experience settlements on the order of 3/4 inch and differential settiements of less than 1/4 inch. 7.6 Lateral Resistance The following values may be utilized in resisting lateral loads imposed on the structure. Requirements of the Uniform Building Code should be adhered to when the coefficient of friction and passive pressures are combined. Coefficient of Friction - 0.35 Equivalent Passive Fluid Pressure = 200 Ibs./cu.ft. Maximum Passive Pressure = 2,000 Ibs./cu.ft. The passive pressure recommendations are valid only for approved compacted fill soils. 7.7 Retaininq Wall Desiqn Parameters Active earth pressures against retaining wall will be equal to the pressures developed by the following fluid densities. These values are for granular baclcfill material placed behind the walls at various ground slopes above the walls. NorCal Engineering April 4, 2005 Project Number 12040-05 Page 12 Surface Slope of Retained Materials Equivalent Fluid (Horizontal to Vertical) Densitv (Ib./cu.ft.) Level 30 5 to 1 35 4 to 1 38 3 to 1 40 2 to 1 45 Any applicable short-term construction surcharges and seismic forces should be added to the above lateral pressure values. A backfill zone of non-expansive material shall consist of a wedge beginning a minimum of one horizontal foot from the base ofthe wall extending upward at an inclination no less than 1/4 to 1 (horizontal to vertical). All walls shall be waterproofed as needed and protected from hydrostatic pressure by a reliable permanent subdrain system. 7.8 Slab Desiqn All new concrete slabs-on-grade shall be at least five inches in thickness in office areas and six inches in warehouse, and placed on approved subgrade soils compacted to 95% in the upper one foot. Reinforcement requirements and an increase in thickness of the slabs-on-grade may be necessary based upon proposed loading conditions in the structures. A vapor barrier sandwiched between by a four-inch thick sand layer should be utilized in areas, which would be sensitive to the infiltration of moisture. All concrete slab areas to receive floor coverings should be moisture tested to meet all manufacturer requirements prior to placement. The upper 18 inches shall be saturated to 3% over optimum moisture content to a depth of 18 inches priorto pouring concrete. NorCal Engineering April 4, 2005 Project Number 12040-05 Page 13 7.9 Pavement Section Desiqn The table below provides a preliminary pavement design based upon an estimated R-Value of 25 for the proposed pavement areas. Final pavement design may need to be based on R-Value testing of the subgrade soils near the conclusion of rough grading to assure that these soils are consistent with those assumed in this preliminary design. Tvoe of Traffic Traffic Index Asphaltic Concrete (in) Base Material (in) Parking Stalls 4.0 3.0 4.0 Light Vehicle Circulation Areas 5.0 3.0 6.5 Medium Truck Access Areas (GVW < 42,000 lbs.; 3 axle) 6.0 3.5 9.0 Heavy Truck Access Areas (GVW < 90,000 lbs.; 5 axle) 7.0 4.0 12.0 All concrete slabs to be utilized for pavement shall be a minimum of six inches in thickness and placed on approved subgrade soils. In addition, the above recommendations are based upon estimated traffic loads. Client should submit anticipated traffic loadings, when available, so that pavement sections may be reviewed to determine adequacy to support these loads. Any approved base material shall consist of a Class II aggregate or equivalent and should be compacted to a minimum of 95% relative compaction. All pavement materials shall conform to the requirements set forth by the City of Carlsbad. The base material and asphaltic concrete should be tested prior to delivery to the site and during placement to determine conformance with the project specifications. A pavement engineer shall designate the specific asphalt mix design to meet the required project specifications. NorCal Engineering April 4, 2005 Project Number 12040-05 Page 14 7.10 Utilitv Trench and Excavation Bactcfill Trenches from installation of utility lines and other excavations may be backfilled with on-site soils or approved imported soils compacted to a minimum of 90% relative compaction. All utility lines shall be properly bedded with clean sand having a sand equivalency rating of 30 (SE > 30) or more. This bedding material shall be thoroughly water jeti:ed around the pipe structure prior to placement of compacted backfill soils. 7.11 Corrosion Desiqn Criteria Representative samples of the surficial soils, typical of the subgrade soils expected to be encountered within foundation excavations and underground utilities were tested for corrosion potential. Representative samples of the surilcial soils, typical of the subgrade soils expected to be encountered within foundation excavations and underground utilities were tested for corrosion potential. The minimum resistivity value obtained for the samples tested is representative of an environment that may be severely corrosive to metals. The soil pH value was considered mildly acidic and may not have a significant effect on soil corrosivity. Consideration should be given to corrosion protection systems for buried metal such as protective coatings, wrappings or the use of PVC where permitted by local building codes. According to the latest 'Uniform Building Code (UBC) Table 19A-A-4 - Requirements for Concrete Exposed to Sulfate-Containing Solutions', these contents revealed negligible levels of sulfate exposure. Therefore, a Type II cement according to latest UBC specifications may be utilized for building foundations at this time. Additional sulfate tests shall be performed at the completion of site grading to assure that these soils are consistent with the recommendations stated in this design. Sulfate test results may be found on the attached Table 111. NorCal Engineering April 4, 2005 Project Number 12040-05 Page 15 8.0 Closure The recommendations and conclusions contained in this report are based upon the soil conditions uncovered in our test excavations. No warranty of the soil condition between our excavations is implied. NorCal Engineering should be notified for possible further recommendations if unexpected to unfavorable conditions are encountered during construction phase. It is the responsibility of the owner to ensure that all information within this report is submitted to the Architect and appropriate Engineers for the project. This firm should have the opportunity to review the final plans to verify that all our recommendations are incorporated. This report and all conclusions are subject to the review of the controlling authorities for the project. A preconstruction conference should be held between the developer, general contractor, grading contractor, city inspector, architect, and soil engineer to clarify any questions relating to the grading operations and subsequent construction. Our representative should be present during the grading operations and construction phase to certify that such recommendations are complied within the field. This geotechnical investigation has been conducted in a manner consistent with the level of care and skill exercised by members of our profession currently practicing under similar conditions in the Southern California area. No other warranty, expressed or implied is made. NorCal Engineering April 4, 2005 Page 16 Project Number 12040-05 We appreciate this opportunity to be of service to you. If you have any further questions, please do not hesitate to contact the undersigned. Respectfully submitted, NORCAL ENGINEERING Keith D. Tucker Project Engineer R.G.E. 841 Troy D. Norrell President NorCal Engineering April 4, 2005 Project Number 12040-05 Page 17 SPECIFICATIONS FOR PLACEIVIENT OF COMPACTED FILL Excavation Any existing low-density soils and/or saturated soils shall be removed to competent natural soil under the inspection of the Soils Engineering Firm. After the exposed surface has been cleansed of debris and/or vegetation, it shall be scarified until it is uniform in consistency, brought to the proper moisture content and compacted to a minimum of 90% relative compaction (in accordance with ASTM: D-1557). In any area where a transition between fill and native soil or between bedrock and soil are encountered or other areas as required in this report, additional excavation beneath foundations and slabs will be necessary in order to provide uniform support and avoid difi'erential settlement of the structure. Verification of elevations during this work and all grading operations will be the responsibility of the owner or his designated representative and not NorCal Engineering. Materia! For Fill The on-site soils or approved import soils may be utilized for the compacted fill provided they are free of any deleterious materials and shall not contain any rocks, brick, asphaltic concrete, concrete or other hard materials greater than eight inches in maximum dimensions. Any import soil must be approved by the Soils Engineering firm a minimum of 24 hours priorto importation of site. Placement of Compacted Fill Soils The approved fill soils shall be placed in layers not excess of six inches in thickness. Each lift shall be uniform in thickness and thoroughly blended. The fill soils shall be brought to within 2% of the optimum moisture content, unless otherwise specified by the Soils Engineering firm. Each lift shall be compacted to a minimum of 90% relative compaction (in accordance with ASTM: D-1557) and approved prior to the placement of the next layer of soil. Compaction tests shall be obtained at the discretion ofthe Soils Engineering firm but to a minimum of one test for every 500 cubic yards placed and/or for every 2 feet of compacted fill placed. The minimum relative compaction shall be obtained in accordance with accepted methods in the construction industry. The final grade of the structural areas shall be in a dense and smooth condition prior to placement of slabs-on-grade or pavement areas. No fill soils shall be placed, spread or compacted during unfavorable weather conditions. When the grading is interrupted by heavy rains, compaction operations shall not be resumed until approved by the Soils Engineering firm. NorCal Engineering April 4, 2005 Project Number 12040-05 Page 18 Grading Observations The controlling governmental agencies should be notified prior to commencement of any grading operations. This firm recommends that the grading operations be conducted under the observation of a Soils Engineering firm as deemed necessary. A 24 hour notice must be provided to this firm prior to the time of our initial inspection. Observation shall include the clearing and grubbing operations to assure that all unsuitable materials have been properly removed; approve the exposed subgrade in areas to receive fill and in areas where excavation has resulted in the desired finished grade and designate areas of overexcavation; and perform field compaction tests to determine relative compaction achieved during fill placement. In addition, all foundation excavations shall be observed by the Soils Engineering firm to confirm that appropriate bearing materials are present at the design grades and recommend any modifications to construct footings. NorCal Engineering INTERSTATE 15 AVENIDA ENCIN^_ T'=100' NorCal Engineering SOILS AND GEOTECHNICAL CONSULTANTS LOCATION OF FIELD EXPLORATIONS TOYOTA CAFILSBAD LOCATION OF FIELD EXPLORATIONS PROJECT 12040-05 I DATE APRIL 2005 LOCATION OF FIELD EXPLORATIONS April 4, 2005 Project Number 12040-05 Page 19 List of Appendices (in order of appearance) Appendix A - Loq of Excavations • Log of Borings B-1 to B-4 • Appendix B - Laboratorv Tests • Table I - Maximum Dry Density • Table II - Expansion • Table III - Corrosion • Plate A - Direct Shear • Plate B - Consolidation NorCal Engineering April 4, 2005 Project Number 12040-05 Page 20 Appendix A NorCal Engineering MAJOR DIVISION GRAPHIC .tSYMRni LETTER .<?YMRni TYPICAL DESCRIPTIONS COARSE GRAINED SOILS MORE THAN 50% OF MATERIAL 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 OR NO FINES) GW WELL-GRADED GRAVELS, GRAVEL. SAND MIXTURES, LITTLE OR NO FINES I "^Bv^ GP POORLY-GRADED GRAVELS, GRAVEL-SAND MIXTURES, LITTLE OR NO FINES GRAVELS WITH FINES (APPRECIABLE AMOUNT OF FINEST GM SILTY GRAVELS, GRAVEL-SAND- SILT MIXTURES GC CLAYEY GRAVELS, GRAVEL-SAND- CLAY MIXTURES CLEAN SAND (LITTLE OR NO FINES) SW WELL-GRADED SANDS, GRAVELLY SANDS, LITTLE OR NO FINES SP POORLY-GRADED SANDS, GRAVEL- LY SANDS, LITTLE OR NO FINES SANDS WITH FINE (APPRECIABLE AMOUNT OF FINES) SM SILTY SANDS, SAND-SILT MIXTURES SC CLAYEY SANDS, SAND-CLAY MIXTURES FINE GRAINED SOILS MORE THAN 50% OF MATERIAL IS SMALLER THAN NO. 200 SIEVE SIZE ML INORGANIC SILTS AND VERY FINE SANDS, ROCK FLOUR, SILTY OR CLAYEY FINE SANDS OR CLAYEY SILTS WITH SLIGHT PLASTICITY SILTS AND CLAYS LIQUID LIMIT I F.C;R THAN F.n 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 AND CLAYS LIQUID LIMIT GREATER THAN 50 MH INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE SAND OR SILTY SOILS CH INORGANIC CLAYS OF HIGH PLASTICITY. FAT CLAYS 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 USED TO INDICATE BORDERLINE SOIL CLASSIFICATIONS UNIFIED SOIL CLASSIFICATION SYSTEIVI NorCal Engineering KEY: m c [J Indicates 2.5-inch Inside Diameter. Ring Sample. Indicates 2-inch OD Split Spoon Sample (SPT). Indicates Shelby Tube Sample. Indicates No Recovery. Indicates SPT with 140# Hammer 30 in. Drop. Indicates Bulk Sample. Indicates Small Bag Sample. Indicates Non-Standard Indicates Core Run. COMPONENT PROPORTIONS COMPONENT DEFINITIONS COMPONENT SIZE RANGE Boulders Cobbles Gravel Coarse gravel Fine gravel Sand Coarse sand Medium sand Fine sand Silt and Clay Larger than 12 in 3 in to 12 in 3 in to No 4 (4.5mm ) 3 in to 3/4 in 3/4 in to No 4 (4.5mm ) No. 4 ( 4.5mm ) to No. 200 ( 0.074mm ) No. 4 ( 4.5 mm ) to No. 10 ( 2.0 mm ) No. 10 ( 2.0 mm ) to No. 40 ( 0.42 mm ) No. 40 ( 0.42 mm ) to No. 200 ( 0.074 mm ) Smaller than No. 200 ( 0.074 mm ) DESCRIPTIVE TERMS RANGE OF PROPORTION Trace 1 - 5% Few 5 -10% Little 10-20% Some 20 - 35% And 35 - 50% MOISTURE CONTENT DRY Absence of moisture; dusty, DRY dry to the touch. DAMP Some perceptible DAMP moisiure; below optimum MOIST No visible water; near optimum MOIST moisture content WET Visible free water, usually WET soil is below water table. RELATIVE DENSITY OR CONSISTENCY VERSUS SPT N -VALUE COHESIONLESS SOILS COHESIVE SOILS Density N (blows/ft) Consistency N (blows/ft) Approximate Undrained Shear Strength (psf) Very Loose Loose Medium Dense Dense Very Dense Oto 4 4 to 10 10 to 30 30 to 50 over 50 Very Soft Soft Medium Stiff Stiff Very Stiff Hard Oto 2 2 to 4 4 to 8 8 to 15 15 to 30 over 30 <250 250 - 500 500 - 1000 1000 - 2000 2000 - 4000 >4000 NorCal Engineering Project Toyota Carlsbad/Carlsbad Dateof Drilling: 3/19/05 Groundwater Depth: 26" Drilling IVIethod: Hollowstem Auger 1 Hammer Weight: 140 Ibs. Drop:30" Log of Boring B-1 Samples" Depth (feet) Geotechnical Description Surface Elevation Not Measured Lith-ology 1 = m 8 1? S Laboratoty 10 15 20 -25 -30 -35 FILL SOILS Sandy CLAY Grey to brown, firm, very moist 1/2/2 23.7 21.4 NATURAL SOILS Silty sandy CLAY Grey-brown, firm, very moist Change to brown @ 14' Silty fine to medium grained SAND Brown, dense, moist Increase in moisture content with depth Gravel and rock @ 25' SANDSTONE with SILTSTONE lenses Light brown, very dense, damp Extremely dense @ 34' 2/5/6 16.9 3/6/6 18.9 6/14/14 10.9 7/15/16 12.9 31/50-3" 13.0 NorCal Engineering Project No. 12040-05 Project Toyota Carlsbad/Carlsbad Date of Drilling: 3/19/05 Groundwater Depth: 26' Drilling Method: Hollowstem Auger Hammer Weight: 140 Ibs. Drop: 30" Samoles Laboratorv Log of Boring B-1 Depth (feet) 35 Geotectinical Description Surface Elevation Not Measured Lith-ology u Q. 1 = m 8 Q •40 •45 •50 •55 •60 -65 •70 SANDSTONE Bedrock Light brown, entremely dense, damp Boring completed at depth of 50' 66-6" 11.6 :J0/>60-3 11.4 63-6" 12.7 74-6" 12.2 NorCal Engineering Project No. 12040-05 Project Toyota Carlsbad/Carlsbad Date of Drilling: 3/19/05 Groundwater Depth: None Encountered Drilling Method: Hand Auger Hammer Weight: Drop: Log of Boring B-2 Samples Laboratory Depth (feet) Geotechnical Description Surface Elevation Lith-ology 0) a l/l CQ 5? 3_ S o in -10 15 20 •25 -30 -35 FILL SOILS Clayey SAND with minor debris Brown, medium dense, very moist NATURAL SOiLS Clayey SAND Brown, dense, moist to slightly high moisture content .^Increase in density with depth Slightly silty fine to medium grained SAND . Brown, dense, moist Silty sandy CLAY \Brown, stiff to very stiff, moist to slightly high moisture content Boring completed at depth of 8' 0 0 16.1 15.9 15.3 25.0 112.8 112.4 110.1 NorCal Engineering Project No. 12040-05 Project Toyota Carlsbad/Carlsbad Date of Drilling: 3/19/05 Groundwater Depth: None Encountered Drilling Method: Hand Auger Hammer Weight: Drop: Log of Boring B-3 Depth (feet) Geotechnical Description 0 Surface Elevation Lith-ology Samples o a. 1 = O 3 ffl Laboratory Q gs in -10 - 15 -20 25 30 35 FILL SOILS Clayey SAND to slightly silty fine to medium grained SAND \ Medium dense, very moist to moist at one foot NATURAL SOILS Clayey SAND \Brown, dense, moist Boring completed at depth of 3.5' due to very dense soils 16.7 114.2 NorCal Engineering Project No. 12040-05 Project Toyota Carlsbad/Carlsbad Date of Drilling: 3/19/05 Groundwater Depth: None Encountered Drilling Method: Hand Auger i Hammer Weight: Drop: i Samoles Laboratorv Log of Boring B-4 Depth (feet) Geotechnical Description Surface Elevation Lith-ology ° 3 O 3.-. (Oo^ S_ tjo'C D gs Q in 10 -15 -20 25 30 -35 4" Asphaltic Concrete/Base Dense, very moist Seeping water @ 8" Rock layer @ 16" NATURAL SOILS Silty sandy CLAY Brown, stiff, moist to slightly high in moisture content Grey-brown @ 9' Slightly silty fine to medium grained SAND Brown, dense, damp Boring completed at depth of 20' 20.1 21.6 104.6 105.2 9/15 23.7 103.5 14/15 4.9 109.7 NorCal Engineering Project No. 12040-05 April 4, 2005 Project Number 12040-05 Page 21 Appendix B NorCal Engineering April 4, 2005 Page 22 Project Number 12040-05 TABLE I MAXIMUM DENSITY TESTS (ASTM: D-1557-00) Optimum Maximum Dry Sample Classification Moisture Densitv (Ibs./cu.ft.) B1 @ 0-4' clayey SAND 13.0 121.0 B1 (g8' slightly siity SAND 10.5 123.5 B4 @ 3-6' silty sandy CLAY 14.0 115.0 Sample 81 @ 0-4' Bl @ 8' B4 @ 3-6' TABLE II EXPANSION INDEX TESTS (U.B.C. STD. 18-2) Classification clayey SAND slightly silty SAND silty sandy CLAY Expansion Index 29 01 63 Sample pH Composite 0-3' 6.3 TABLE III CORROSION TESTS Electrical Resistivitv (ohm-cm) 650 Sulfate (%) Chloride (ppm) 0.032 375 ND denotes not detected % by weight ppm - mg/kg NorCal Engineering 2500 2000 00 o. 00 00 ee 00 1500- ae 2 = 1000 500 rT-" ^ 500 1000 1500 ZOOO NORMAL STRESS (PSF) 2500 3000 (R) SYMBOL BORING NUHBER DEPTH (FEET) (DEGREES) C (PSF) DRY DENSITY (PCF) MOISTURE CONTENT (X) X 1 3.0 29 200 112.8 15.9 O 2 3.5 23 375 104.6 15.3 A 4 3-6 27 400 105.9 14.1 • NOTE: TESTS PERFORMED ON SATURATED SAMPLES UNLESS SHOWN BELOW. (FM) FIELD MOISTURE TESTS PERFORMED ON UNDISTURBED SAMPLES UNLESS SHOWN BELOW. (R) SAMPLES REMOLDED AT 90% OF MAXIMUM DRY DENSITY NorCal Engmeering SOILS AND GEOTECHNICAL CONSULTANTS DIRECT SHEAR TEST RESULTS Plate A DIRECT SHEAR TEST RESULTS Plate A PROJECT 12040-05 DATE DIRECT SHEAR TEST RESULTS Plate A llll n \— NOTE: HATER ADDED AT NORMAL PRESSURE AT 1.0 KSF 00 4 00 UJ ce a. z: <3 (_> 0 -PO-\ 10 0.1 0.5 1.0 5 NORMAL PRESSURE (KSF) 10 20 40 SYMBOL BORING NUMBER DEPTH (FEET) DRY DENSITY (PCF) MOISTURE CONTENT {%) LIQUID LIMIT («) PLASTICITY INDEX X 2 5 112.4 15.3 O 2 8 110.1 20.0 A 4 10 103.5 23.7 • 4 15 109.7 4.9 C(»1PRESSI0N REBOUND (FM) FIELD MOISTURE - NO WATER ADDED (R) SAMPLE REMOLDED AT 90X OF MAXIHUM DRY DENSITY NorCal Engineering SOILS AND GEOTECHNICAL CONSULTANTS PROJECT 12040-05 I DATE CONSOLIDATION TEST RESULTS Plate B Excavation Embankment Export EARTHWORK CALCULATIONS AVENIDA ENCINAS ROAD WIDENING CUP 05-09/CDP 05-19/SDP 91-12A PUBLIC IMPROVEMENTS - DWG 441-6 W.O. 591-0804-605 DATE 07-28-06 750 CY 20 CY 730 CY Page 1 of 1