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BRES2017-0357 Geotechnical ReportLANUMAK 780 N. 4th Street El Centro, CA 92243 Geo-Engineers and Geologists (760) 370-3000 a MBE Colandmark@landmark-ca.com mps VE D 77-948 Wildcat Drive Palm Desert, CA 92211 March 27, 2018 (760) 360-0665 JUL 0 3 2018 9chandra@landmark-ca.com Mr. Alan McNeil GT7y OF LA QIJTNTFI McNeil Development, Inc. COMMUNM nEVELOPMENTREC@VF P.O. Box 447 Lake Arrowhead, CA 92352 . MAY 18 2018 Subject: Geotechnical Report Update CITY OF LA QUINT/-; APN 766-060-068 - 58-785 Quarry Ranch Road COMMUNITY DEVELOPMENT La Quinta, California LCI Report No.: LPI8059 Reference: Geotechnical Investigation Report for the proposed short Course Development, The Quarry at La Quinta; prepared by Sladden Engineering, dated July 31, 2002. Soil Grading at La Quinta: Dear Mr. McNeil: As requested, LandMark C, ort for th oposed short Course Development, The Quarry r ted December 3, 2002. TY F LA Q INTA BUILDING DIVISION REVIEWED FOR CODE COMPLIANCE a report to the referenced geotechnical investigation report for the proposed single-family residence project, in The Quarry of La Quinta, in the city of La Quinta, California. The initial field investigation was conducted in July 2002, and the rough grading operation was completed in December 2002, and the reports were prepared by Sladden Engineering in 2002. Our site visit on March 21, 2018 found that the site conditions were similar as those encountered after the rough grading operation conducted in December 2002. Based on our present field observations and the clients similar project intentions, it is our opinion that the findings, recommendations and conclusions in the referenced geotechnical investigation and rough grading reports are still applicable, except for the seismic parameters and new building pad preparation. K� r .LA fl 780 N. 4th Street _o-Engineers and El Centro, CA 92243 Geologists (760) 370-3000 a MBE Company landmark@landmark-ca.com 77-948 Wildcat Drive Palm Desert, CA 92211 17601 360-0665 March 29, 2018 gchandra@landmark-ca.com MA �� C� LDA— Lake LA QuINTA ILDING DIVISION EVIEWED FOR Mr. Alan McNeil CODERECEIVED McNeil Development, Inc.COMPLIANCE P.O. Box 447 zd8 BY Arrowhead, CA 923 52iAY 2ll 8 �O - 093 CITY OF LA QUINT11 Subject: APN 766-060-068 COMMUNITY DEVELOPMENT 58-785 Quarry Ranch Road La Quinta, California LCI Report No.: LP18059 References: Grading Plans for the subject project, prepared by JHA Engineering, dated March 13, 2018. Structural Plans for the subject project, prepared by APEC-X, Inc, dated April 10, 2017. Dear Mr. McNeil: In response to your request, LandMark Consultants, Inc. has reviewed from a geotechnical standpoint the grading and foundation plans, for the subject project: • Grading Plan page 1 • Structural Plan pages S-1; S-2 and S-4 The purpose of our review was to evaluate compliance with the intent of the recommendations contained in our geotechnical investigation report for the subject site. The submitted plans are in general accordance with the recommendations presented in our geotechnical report update for the subject entitled APN 766-060-068 prepared by LandMark Consultants, Inc., dated March 27, 2018. S4 APN 766-060-068 General Ground Motion Analysis LCI Re ort Na.: LP 18059 The project site is considered likely to be subjected to moderate to strong ground motion from earthquakes in the region. Ground motions are dependent primarily on the earthquake magnitude and distance to the seismogenic (rupture) zone. Acceleration magnitudes also are dependent upon attenuation by rock and soil deposits, direction of rupture and type of fault; therefore, ground motions may vary considerably in the same general area. CBC General Ground Motion Parameters: The 2016 CBC general ground motion parameters are based on the Risk -Targeted Maximum Considered Earthquake (MCER). The U.S. Geological Survey "U.S. Seismic Design Maps Web Application" (USGS, 2014) was used to obtain the site coefficients and adjusted maximum considered earthquake spectral response acceleration parameters. The site soils have been classified as Site Class D (stiff soil profile). Design spectral response acceleration parameters are defined as the earthquake ground motions that are two-thirds (2/3) of the corresponding MCER ground motions. Design earthquake ground motion parameters are provided in Table 2. A Risk Category II was determined using Table 1604.5 and the Seismic Design Category is D since Si is less than 0.75. The Maximum Considered Earthquake Geometric Mean (MCEG) peak ground acceleration (PGAM) value was determined from the "U.S. Seismic Design Maps Web Application" (USGS, 2013) for liquefaction and seismic settlement analysis in accordance with 2013 CBC Section 1803.5.12 and CGS Note 48 (PGAM = FrGA*PGA). A PGAM value of 0.5g has been determined for the project site. House Pad Preparation Prior to any fill and/or cut operations, the existing surface soil within the proposed house pad areas should be scarified to a depth of 8 inches, uniformly moisture conditioned to at least 2% over optimum moisture content, and re -compacted a minimum of 90% of the maximum density determined in accordance with ASTM D1557 methods. LandMark Consultants, Inc. age 2 APN 766-060-068 I.CI Re vrt No.: LP18U59 We have prepared this letter for your exclusive use in substantial accordance with the generally accepted geotechnical engineering practice as it existed in the site area at the time of our study. No warranty is expressed or implied. It should be noted that the submitted plans were not reviewed for conformance with other clients, governmental or consultant requirements. We appreciate the opportunity to be of service. Should you have any questions, please call our office. amcere Yours, Q�DFESSIp Laird ark Consultants, Inc. �p � CH4 �9{� LU No. C 34432 Crreg IUI. C dra, .E., M.ASCE Principal ginee CIVIL. Landmark Consultants, Inc. APN 766-060-068 LCI Report No.: LP18059 The native granular soil is suitable for use as compacted fill and utility trench backfill. The native soil should be placed in maximum 8 inches lifts (loose), uniformly moisture conditioned to at least 2% of optimum moisture content, and re -compacted to a minimum of 90% of the maximum density determined in accordance with ASTM D1557 methods. Imported fill soil (if needed) should similar to onsite soil or non -expansive, granular soil meeting the USCS classifications of SM, SP-SM, or SW-SM with a maximum rock size of 3 inches. The geotechnical engineer should approve imported fill soil sources before hauling material to the site. Imported granular fill should be placed in lifts no greater than 8 inches in loose thickness, uniformly moisture conditioned to at least 2% over optimum moisture content, and re -compacted to a minimum of 90% of the maximum density determined in accordance with ASTM D1557 methods. We have prepared this letter for your exclusive use in accordance with the generally accepted geotechnical engineering practice as it existed within the site area at the time of our study. No warranty is expressed or implied. It should be noted that the submitted plans were not reviewed for conformance with other clients, governmental or consultant requirements. We appreciate the opportunity to be of service. Should you have any questions, please call our office at (760)360-0665. Sincerely Yours, Greg M. Principal Consultants, Inc. .E., M.ASCE C ell 6 2? m L" No. C 34432 M M, OF CA Attachments: Appendix A: Table 2 Appendix B: Geotechnical Investigation Report for the proposed Short Course Development, The Quarry at La Quinta, LA Quinta, California, prepared by Sladden Engineering., dated July 31, 2002. APN 766-060-068 LCI Project No. LP18059 Table 2 2013 California Building Code (CBC) and ASCE 7-10 Seismic Parameters CBC Reference Soil Site Class: D Table 20.3-1 Latitude: 33.6236 N Longitude:-116.2714 W Risk Category: II Seismic Design Category: D Maximum Considered Earthquake (MCE) Ground Motion Mapped MCER, Short Period Spectral Response SS 1.500 g Figure 1613.3.1(1) Mapped MCER 1 second Spectral Response S, 0.600 g Figure 1613.3.1(2) Short Period (0.2 s) Site Coefficient Fe 1.00 Table 1613.3.3(1) Long Period (1.0 s) Site Coefficient F, 1.50 Table 1613.3.3(2) MCEo Spectral Response Acceleration Parameter (0.2 s) Seas 1.500 g = F. * S, Equation 16-37 MCEo Spectral Response Acceleration Parameter (1.0 s) SM, 0.900 g = F, * St Equation 16-38 Design Earthquake Ground Motion Design Spectral Response Acceleration Parameter (0.2 s) SDs 1.000 g = 2/3*SMs Equation 16-39 Design Spectral Response Acceleration Parameter (1.0 s) SDI 0.600 g = 2/3*SMI Equation 16-40 Ti, 8.00 sec ASCE Figure 22-12 To 0.12 sec =0.2*SDI/SDs Ts 0.60 sec =SDI/SDs Peak Ground Acceleration PGAM 0.50 g ASCE Equation 11.8-1 1llrlri tiiii iii! �i I!! 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[]R^�+7wi�2.40 liiilili!!!!Mi!!ii2.60 -- • • - • . - • Design Response Spectra MCER Response Spectra I GEOTECHNICAL INVESTIGATION PROPOSED SHORT COURSE DEVELOPMENT THE QUARRY AT LA QUINTA LA QUINTA, CALIFORNIA -Prepared By- Sladden Engineering 39-725 Garand Lane, Suite G Palm Desert, California 92211 (760) 772-3893 i I *) Sladden Fng neerin— 6782 Stanton Ave„ Suite E, Buena Park, CA 00621 (562) 864-4121 (714) 52:3-0952 Fax (714) 523-1360 39-725 Garandt.n., Suite G, 1."alm Desert, CA 92211 (76Q) '72-3893 Fax (760) 772.3895 July 31, 2002 Quarry Ranch, LLC I Quarry Lane La Quinta, California 92253 Attention: Mr. John Shaw Project: Proposed Short Course Development The Quarry at La Quinta La Quinta, California Subject: Geotechnical Investigation Project No. 544-2098 02-07-445 Presented herewith is the report of our Geotechnical Investigation conducted at the site of the proposed new short course and surrounding residential lots to be located just south and east of the existing Quarry at La Quinta development in the City of La Quinta, California. The investigation was performed in order to provide recommendations for site preparation and to assist in foundation design for the proposed residential structures. This report presents the results of our field investigation and laboratory testing along with conclusions and recommendations for foundation design and site preparation. This report completes our original scope of services as described in our proposal dated June 14, 2002. We appreciate the opportunity to provide service to you on this project. if you have any questions regarding this report, please contact the undersigned Respectfully submitted, SLADDEN ENGIVI ERING -� �•= r! li •,;err �sr��i Brett L. Ande:rseo�' " f _ i!o a 45335 Principal Engineer` SER/pc Copies: 6/Quarry Ranch, LLC OEOTECHM|CAL|NVES|lGATON PROPOSED SHOKTCOURSEDGVB.0PK4RNT THE QUARRY ATLAQOINT& L/\()UIN7A`CALIFORNIA ,Iu|v J \. 2OO2 TABLE OF CONTENTS INTRODUCTION -~-~~-''''~—'''`r'-.'~`-~~~^^`''~-,�—r~—^~`--~�^'�~--�r-- | SCOPE OFWORK ........ ��,...... .'............. '..... "~..=_^'_~.~._.--'-_-.�',.—_r \ PROJECT DB8CRlPT0ON,,,`....... _.^................ ...'._,_._.°..^....~_..,,_^.~-~-_.--~.~. | SUBSURFACE CONDITIONS ................... .'.............. ..*.�.+......_°._..�°--*'.-,p�~. | CONCLUSIONS AND RECQM&8GNDATk]N8-----.-.......~._..-... 2 FoundationDesign ....................................... ~.~°.~..~.'-........ ..................... .... .~_~~., 3 8r�)en`eo�........---..~��_..°...r^..—~-`_'r.__�._.__'..~—.-~.-.,-, 3 LateralDesign --.....-.~............ .......... ,................ ,,-' ] Retaining Walls .-----..~___..~.^.~-._......... ] BxouuyiveQoi|a�~�.,-�_`�.�~..,.`'..~....... .~.—_=........... 4 Concrete Slabs -on -Grude,.~'...__............. ....... ........ 4 SolubleSulfates ................................ ,.~*............... .................. ....... ................. ._-...- 4 Shrinkage and Subsidence ................... ............ ........ ,~,.^-,^....... 4 General S-ite Grading .----------------.--...-......... ~. 4 \. Clearing and Grubbing ......................... .......................... ..... 4 2. PreparationnfBuilding Areas ........................................... ........~-_.`~_5 3. Preparationof Surfaces tnReceive Compacted FiU_-_-.-._.~...�__-�....... -^ 5 4. Placement ofCompacted Fill .......................................... -............ ...... ..-` 5 5' Preparation of Slab and Pavement Areas ........ ,.~....+',..,~~......... -^,` ......... 5 6. Testing and Inspection ----`-------~j APPBNDCXA- Site Plan and Boring Logs Field Exploration APPENDIX 0- Laboratory Testing Laboratory Test Results APPENDIX C' |997OBCSeismic Desi�nCh�rim July 31, 2002 INTRODUCTION Project No. 544-2098 02-07-445 ' This report presents the results of our Geotechnical Investigation performed in order to provide recommendations for site preparation and to assist in the design and construction of the residential lots surrounding the proposed short course. The site is located just south of and east of the existing Quarry at La Quinta development in the City of La Quinta, California. The associated improvements will include paved roadways, concrete driveways, concrete walkways, various underground utilities, and landscape areas. SCOPE OF WORK The purpose of our investigations was to determine cer ain engineering characteristics of the near surface soils on the site in order to dovelop recomntcoubitions for'foundation design and site preparation. Our investigation included field exploration, laboratory testing, engineering analysis and the preparation of this report. Evaluation of environmental issues or hazardous wastes was not within the scope of services provided. Our investigation was performed in accordance with contemporary geotechnical engineering principles and practice. We make no other warranty, either express or implied. PROJECT DESCRIPTION The project site is located just south and east of the existing Quarry at La Quinta development in the City of La Quinta, California. The preliminary plans indicate that the project will consist of a new par 3 golf course and surrounding residential lots. It is our understanding that the proposed residential buildings will be of relatively lightweight wood -frame construction and will be supported by conventional shallow spread footings and concrete slabs on grade. The associated site improvements will include, concrete walkways and driveways, paved roadways, landscape areas and various underground utilities. The project site is presently vacant and the ground surface is covered with scattered desert brush, short grass, weeds and minor debris. The majority of the project is relatively level throughout with an overall downward slope to the north and east. Two large lots are located on the natural hillside just south of the existing Quarry at La Quinta Golf Course. The adjacent properties to the south, and east are presently occupied by single family residences. Based upon our previous experience with lightweight wood -frame structures, we expect that isolated column loads will be less than 30 kips and wall loading will be less than to 3.0 kips per linear foot. Grading is expected to include cuts and fills to match the nearby elevations and to construct level building pads. This does not include removal and/or recompaction of the primary foundation bearing soils within the building areas. If the anticipated foundation loading or site grading varies substantially from that assumed, the recommendations included in this report should be reevaluated. SUBSURFACE CONDITIONS The site is underlain primarily by fine to coarse grained alluvial sands with scattered gravel and cobbles. The alluvial sands were fairly uniform in composition except for gravel and cobble content. Tile alluvial sands typically contained less than ten percent fines (clay and silt sized particles). In general, the site soils appear somewhat loose near the surface but field blow counts indicate that density generally increases with depth. The site soils were found to be dry throughout the depth of our exploratory borings. July 3 I, 2002 Project No. 544-2098 02-07-445 Laboratory classification testing indicates that the near surface soils consist primarily of fine to coarse grained alluvial sands. Expansion testing indicates that the surface soils are non -expansive and fall within the "very low" expansion category in accordance with the Uniform Building Code classification system. The somewhat loose and dry conditions suggest that the near surface soils may be susceptible to detrimental settlements due to the anticipated foundation loading and the introduction of water. Groundwater was not encountered within our borings but is expected to be in excess of 200 feet below the existing ground surface in the vicinity of the site. Groundwater should not be a factor in foundation design or construction, CONCLUSIONS AND RECOMMENDATIONS Based upon our field and laboratory investigation, it is our opinion that the proposed residential development is feasible from a soil mechanic's standpoint provided that the recommendations included in this report are considered in building foundation design and site preparation. Due to the somewhat loose and potentially compressible condition of some of the near surface soils, remedial grading including watering and recompaction is recommended for the proposed building areas. We recommend that remedial grading within the proposed building areas include extensive site watering and recompaction of the primary foundation bearing soils in order to provide a uniform mat of compacted soils beneath the building foundations. Specific recommendations for site preparation are presented in the Site Grading section of this report. Groundwater was not encountered within our borings and groundwater is expected to be in excess of 200 feet below the existing ground surface in the vicinity of the site. Due to the depth to groundwater, specific liquefaction analyses were not performed. Based upon the depth to groundwater, the potential for liquefaction and the related surficial affects of liquefaction impacting the site are considered negligible. The site is located within an active seismic area of Southern California within approximately 15.0 kilometers of the San Andreas fault. Strong ground motion resulting from earthquake activity along the nearby San Andreas or San Jacinto fault systems is likely to impact the site during the anticipated lifetime of the structures. Structures should be designed by professionals familiar with the geologic and seismic setting of the site. As a minimum, structure design should conform with Uniform Building Code (UBC) requirements for Seismic Zone 4. Pertinent seismic design parameters as included within the 1997 UBC are summarized in Appendix C. Caving did occur within each of our exploratory borings and the surface soils will be susceptible to caving within deeper excavations. All excavations should be constructed in accordance with the normal CalOSHA excavation criteria. On the basis of our observations of the materials encountered, we anticipate that the subsoils will conform to those described by CalOSHA as Type C. Soil conditions should be verified in the field by a "Competent person" employed by the Contractor. The surface soils encountered during our investigation were found to be non -expansive, Laboratory testing indicated an Expansion Index of 0 which corresponds with the "very low" category in accordance with UBC Standard 18-2. If imported soils are to be used during grading, they should have an Expansion Index of less than 20. July 31, 2002 -3- Project No. 544-2048 02-07-445 The following recommendations present more detailed design criteria that have been developed on the basis of our field and laboratory investigation. Foundation Design: The results of our investigation indicate that either conventional shallow continuous footings or isolated pad footings, which are supported upon properly recompacted soils, may be expected to provide satisfactory support for the proposed residential structures. Recompaction should be performed as described in the Site Grading Section of this report. Footings should extend at least 12 inches beneath lowest adjacent grade. Isolated square or rectangular footings at least 2 feet square may be designed using an allowable bearing pressure of 1800 pounds per square foot. Continuous footings at least 12 inches wide may be designed using an allowable bearing pressure of 1500 pounds per square foot. Allowable increases of 200 psf for each additional 1 foot of width and 250 psf for each additional 6 inches of depth may be utilized if desired. The maximum allowable bearing pressure should be 2500 psf. The allowable bearing pressures are for dead and frequently applied live loads and may be increased by 1/3 to resist wind, seismic or other transient loading. Care should be taken_ to see that bearing soils are not allowed to become saturated from the ponding of rainwater or excessive irrigation. Drainage from the building areas should be rapid and complete. The recommendations made in the preceding paragraphs are based on the assumption that all footings will be supported upon properly compacted soil. All grading shall be performed under the testing and inspection of the Soils Engineer or his representative. Prior to the placement of concrete, we recommend that the footing excavations be inspected in order to verify that they extend into compacted soil and are free of loose and -disturbed materials. Settlements: Settlements may result from the anticipated foundation loads. These estimated ultimate settlements are calculated to be a maximum of i inch when using the recommended bearing values. As a practical'matter, differential settlements between footings can be assumed as one-half of the total settlement. Lateral Design: Resistance to lateral loads can be provided by a combination of friction acting at the base of the slabs or foundations and passive earth pressure along the sides of the foundations. A coefficient of friction of 0.45 between soil and concrete may be used with dead load forces only. A passive earth pressure of 275 pounds per square foot, per foot of depth, may be used for the sides of footings which are poured against properly compacted native soils. Passive earth pressure should be ignored within the upper I foot except where confined (such as beneath a floor slab). When used in combination, either the passive resistance or the coefficient of friction should be reduced by one-third. Retaining Walls: Retaining walls may be required to accomplish the proposed construction. Cantilever retaining walls may be designed using "active" pressures. Active pressures may be estimated using an equivalent fluid weight of 35 pcf for native backfill soils with level free - draining backfill conditions. July 31, 2002 1 Project No, 544-2098 02-07-445 ( For walls that are restrained, "at rest" pressures should be utilized in design. At rest pressures 1 may be estimated using an equivalent fluid weight of 55 pcf for native backfill soils with level free -draining backfill conditions. Expansive Soils: Due to the prominence of lion -expansive soils on the site, special expansive soil design criteria should not be necessary for the design of foundations and concrete slabs -on - grade. Final foundation and slab design criteria should be established by the Structural Engineer, Concrete Slabs -on -Grade: All surfaces to receive concrete slabs -on -grade should be underlain by recompacted soils as described in the Site Grading Section of this report. Where slabs are to receive moisture sensitive floor coverings or where dampness of the floor slab is not desired, we recommend the use of an appropriate vapor barrier. Vapor barriers should be protected by sand in order to reduce the possibility of puncture and to aid in obtaining uniform concrete curing. Reinforcement of slabs -on -grade in order to resist expansive soil pressures may not be required however, reinforcement will have a beneficial effect in containing cracking due to concrete shrinkage. Temperature and shrinkage related cracking should be anticipated in all concrete slabs -on -grade. Slab reinforcement and the spacing of control joints should be determined by the Structural Engineer. Soluble Sulfates: The soluble sulfate concentrations of the surface soils were determined to be 29 parts per million (ppm). This is within the usual allowable limits for the use of Type II cement and the use of Type V cement or special sulfate resistant concrete mixes should not be necessary. Shrinkage and Subsidence: Volumetric shrinkage of the material that is excavated and replaced as controlled compacted fill should be anticipated. We estimate that this shrinkage could vary from 10 to 15 percent. Subsidence of the surfaces that are scarified and compacted should be between 0.1 and 0.2 tenths of a foot. This will vary depending upon the type of equipment used, the moisture content of the soil at the time of grading and the actual degree of compaction attained. These values for shrinkage and subsidence are exclusive of losses that will occur due to the stripping of the organic material from the site, the removal of oversized materials. General Site Grading: All grading should be performed in accordance with the grading ordinance of the City of La Quinta, California. The following recommendations have been developed on the basis of our field and laboratory testing: 1. Clearing and Grubbing: Proper clearing of any existing vegetation, associated root systems, and debris will be very important. All surfaces to receive compacted fill should be cleared of roots, vegetation, debris, and other unsuitable materials that should be removed from the site. Soils that are disturbed due to the removal of the surface vegetation and debris should be replaced as controlled compacted fill under the direction of the Soils Engineer. July 3 I, 2002 -5- Project No. 544-2098 02-07-445 2. Preparation of Building Area: In order to provide fine and uniform bearing conditions, we recommend watering and recompaction throughout the building and foundation areas. Tile building areas should be watered so that near optimum moisture content is attained to a depth of at least 3 feet below existing grade or 4 feet below pad grade, whichever is deeper. The exposed surface should then be compacted with heavy equipment so that a minimum of 90 percent relative compaction is attained to a depth of at least 2 feet below existing grade or 3 feet below pad grade, whichever is deeper. Fill material may then be placed as recommended in Item 4 below. Overexcavation and recompaction of the surface soils is recommended for transition lots including the 2 lots located within the natural hillside south of the existing Quarry at La Quinta development. 3. Preparation of Surfaces to Receive Compacted Fill: Other areas to receive compacted fill should be brought to near optimum moisture content and compacted to a minimum of 90 percent relative compaction. 4. Placement of Compacted Fill: Fill materials consisting of on -site soils or approved imported granular soils, should be spread in thin lifts, and compacted at near optimum moisture content to a minimum of 90 percent relative compaction. Imported material shall have an Expansion Index not exceeding 20. The contractor shall notify the Soils Engineer at least 48 hours in advance of importing soils in order to provide sufficient time for the evaluation of proposed import materials. The contractor shall be responsible for delivering material to the site that complies with the project specifications. Approval by the Soils Engineer will be based upon material delivered to the site and not the preliminary evaluation of import sources. Our observations of the material encountered during our investigation indicate that compaction will be most readily obtained by means of heavy rubber -wheeled equipment and/or vibratory compactors. At the time of our investigation, the subsoils were found to be very dry. A more uniform and near optimum moisture content should be maintained during recompaction and fill placement. 5. Preparation of Slab and Paving Areas: All surfaces to receive asphalt concrete paving or concrete slabs -on -grade, should be underlain by a minimum compacted fill thickness of 12 inches. This may be accomplished by a combination of scarification and recornpactio❑ of the surface soils and placement of the fill material as controlled compacted fill. Compaction of the slab and pavement areas should be to a minimum of 90 percent relative compaction. 6. Testing and Inspection: During grading tests and observations should be performed by the Soils Engineer or his representative in order to verify that the grading is being performed in accordance with the project specifications. Field density testing shall be performed in accordance with acceptable ASTM test methods. The minimum acceptable degree of compaction should be 90 percent of the maximum dry density as obtained by the ASTM 131557-91 test method. Where testing indicates insufficient density, additional compactive effort shall be applied until retesting indicates satisfactory compaction. July 31, 2002 GENERAL Project No. 544-2098 02-07-44ti The findings and recommendations presented in this report are based upon an interpolation of the soil conditions between the exploratory boring locations and extrapolation of these conditions throughout the proposed building area. Should conditions encountered during grading appear different than those indicated in this report, this office should be notified. This report is considered to be applicable for use by Quarry Ranch, LLC for the specific site and project described herein. The use of this report by other parties or for other projects is not authorized. The recommendations of this report are contingent upon monitoring of the grading operation by a representative of Sladden Engineering. All recommendations are considered to be tentative pending our review of the grading operation and additional testing, if indicated. If others are employed to perform any soil testing, this office should be notified prior to such testing in order to coordinate any required site visits by our representative and to assure indemnification of Sladden Engineering. Our investigation was conducted prior to the completion of plans for the project. We recommend thaf a pre job conference be held on the site prior to the initiation of site grading. The purpose of this meeting will be to assure a complete understanding of the recommendations presented in this report as they apply to the actual grading performed. APPEADIX A Site Phil Bc)rin� Lo,,s Sladden Enrineerin;; APPENDIX A FIELD EXPLORATION For our field investigation, 7 exploratory borings were excavated on June 26, 2002, using a truck mounted Mobile B53 drilling rig and hollow -stem augers. The approximate exploratory boring locations are indicated on the site plan included in this appendix. Boring logs are included in this appendix. Representative undisturbed samples were obtained within our borings by driving a thin -walled steel penetration sampler (California split spoon sampler) or a Standard Penetration Test (SPT) sampler with a 140 pound hammer dropping approximately 30 inches (ASTM D 1586), The number of blows required to drive the samplers 18 inches was recorded in 6-inch increments and blowcounts are indicated on the boring logs. The Caliromia samplers are 3.0 inches in diameter, carrying brass sample rings having inner diameters of 2.5 inches. The standard penetration s smpl4rs are 2.0 inclres in diameter wdit all: ini&r diameter of 1.5 inelms, Undisturbed samples were reilLOVctl Cxtnn the sampler and placed in moisture settled containers in order to preserve the natural soil moisture content. Bulk samples were obtained from the excavation spoils and samples were then transported to our laboratory for further observations and testing. Ok 2 4-6 A 4, 7 North -`' Approximate Boring Locations Boring Location Map Proposed Short Course The Quarry at La Quinta La OUinta, Catifornia Sladden Engineering Proiect Number: 544-2098 :1 Date: 7 - -29-02 Proposed Short Course _ Th_e Quarryat La G uinta / La Quinta, California Date: 6-26-02 Boring (1. 2 LY y o DESCRIPTION A REMARKS a ti O _� - Sand: Brown, SP Fine to coarse grained 5 14/14/18 to 11/17/22 Sand: Brown, SP fine to coarse grained with gravel is 7/17/17 Sand: Brown, fine to coarse SP grained, trace gravel Sand: Brown, slightly silty, ;SP/S 20 37/27/34 fine to coarse grained - 7 - - Recovered Sample ® Unrecovered Sample 25 30 35 40 I45 1 50 1 55 99 I 0.4 t 105 1 0.8 i •-- 104 t 1.0 1 --- 106 1.5 •- 11-N—oGroundwater otal Depth = 21.5' o Bedrock Note: The stratification lines represent the approximate boundaries between the soil types, - the transicions may be gradual. Proposed Short Course The Tarr at La uinta / La uinta California Ii'a e: 6 2fi [l'? Nn.3' Joh No.: F44-2? - .� 5 o -C� o u) DESCRIPTION ; Q W Cd REMARKS �, t~ 1 o 0 a yi~ A co o U PQ c0 o , Sand: Brown, fine to coarse SP grained, trace gravel 8/10/12 0.5 { 10 10/11/12 Sand; Brown, SP 0.7 fine to coarse grained with gravel 15 Sand: Brown, fine to coarse SP 10/20/21 grained, trace gravel 0.9 m Standard Penetration Total Depth = 16.5' Sample No Bedrock �o No Groundwater 25 � I { 30 I 35 1 40 1 - 45 5o 55 Note: The stratification lines represent the approximate boundaries between the soil types; the fronsitions may be gradual, The y o = DES o � � �Ar) U W o Sand: Brc slightly si Fine to co - trace grav 12/16/19 { to 17/20/23 Sand; Bra slightly si fine tom with grav( 20/24)26 W Stand SamE 20 25 30 J5 40 45 50 Proposed Short Course The % u��t.r,y at La Quinta / La ft�inta California ).ate: 6 '7G•D'� _ Horin i No. 6 J01) Na.: 544 41 - a) v o DESCRIPTION A " rn o V GG — 0 _ Sand: Brown, fine to coarse grained with gravel 11/14/16 r-�- 10 - 15/19/22 Sand: Brown, slightly silty, fine to coarse grained 15 .21/23/25 Standard Penetration I •1Sample 20 1 25 30 35 I . 40 45 50 o Q CO ca REMARKS 'o SP 11 11 ... 1 0.3 1 --. 1 0.9 1 0.7 ... Total Depth = 16,5' No Bedrock No Groundwater ri5 Note: The stratifteation lines represent the approximate boundaries betsyeen the soil types; the triicisitions imy be gradual. Proposed Short Course _ Th_e uarry at La �tinta / L_a QL;inta California Date: 6-26• (3`� _ ai C DESCRIPTION Q REMARKS a E-o o - S and: Brown, fine to coarse SP grained, trace gravel a if3�ll.t Y a 0.5 10 91I4l16 ... 0.7 15 Sand: Brown, fine to coarse SP 31/1.8122 grained, trace ravei 0.9 [Standard Penetration Total Depth = M5' sample 1 No Bedrock 20 No Groundwater i 25 j 30 35 40 45 I 50 I Note: The stratification lines 1 55 represent the approximate bOUlldarles hetwt*n the soil types; the truusitions may he gradual. APPENDIX S Laboratory Testing Laboratory Test Results APPENDIX B LABORATORY TESTING Representative bulk and relatively undisturbed soil samples were obtained in the field and returned to our laboratory for additional observations and testing. laboratory testing was generally performed in two phases. The first phase consisted of testing in order to determine the compaction of the existing natural soil and the general engineering classifications of the soils underlying tile site. This testing was performed in order to estimate the engineering characteristics of the soil and to serve as a basis for selecting samples for the second phase of testing. The second phase consisted of soil mechanics testing. This testing including consolidation, shear strength and expansion testing was performed in order to provide a means of developing specific design recommendations based on the mechanical properties of the soil. CLASSIFICATION AND COMPACTION TESTING Unit Weight and Moisture Content Determinations: Each undisturbed sample was weighed and measured in order to determine its unit weight. A small portion of each sample was then subjected to testing in order to determine its moisture content. This was used in order to determine the dry density of the soil in its natural condition. The results of this testing are shown on the Boring Logs. Maximum Density -Optimum Moisture Determinations: Representative soil types were selected for maximum density determinations. This testing was performed in accordance with the ASTM Standard D1557-91, Test Method A. The results of this testing are presented graphically in this appendix, The maximum densities are compared to the field densities of the soil in order to determine the existing relative compaction to the soil. This is shown on the Boring Logs, and is useful in estimating the strength and compressibility of the soil. Classification Testing: Soil samples were selected for classification testing. This testing consists of mechanical grain size analyses and Atterberg Limits determinations. These provide information for developing classifications for the soil in accordance with the Unified Classification System. This classification system categorizes the soil into groups having similar engineering characteristics. The results of this testing are very useful in detecting variations in the soils and in selecting samples for further testing. SOIL MECHANIC'S TESTING Direct Shear Testing: One bulk sample was selected For Direct Shear Testing. This testing measures the shear strength of the soil under various normal pressures and is used in developing parameters for foundation design and lateral design. Testing was performed using recompacted test specimens, which were saturated prior to testing. Testing was performed using a strain controlled test apparatus with normal pressures ranging from 800 to 2300 pounds per square foot. Expansion Testing: One bulk sample was selected for Expansion testing. Expansion testing was performed in accordance with the UBC Standard 18-2. This testing consists of remolding 4-inch diameter by 1-inch thick test specimens to a moisture content and dry density corresponding to approximately 50 percent saturation. The samples are subjected to a surcharge of 144 pounds per square foot and allowed to reach equilibrium. At that point the specimens are inundated with distilled water. The linear expansion is then measured until complete. 124 123 ' 122 � Lz1 A 120 8.5 9 Job No.: 544-2098 i 9.5 10 10.5 11 11.5 12 Moisture Content (%) K-ET ig OF COMPACT Obi ASTM D-1557-91, METHOD A OR C RQ-RING M XIMUM V IT _ iy�F_Qi-IT I@0-5' 123 nplllmlim 1N[�Ml Cal . '1' {'N' 10.3 MAXIMUM DENSITY -OPTIMUM MOISTURE CURVE I A A .2 I July 31, 2002 -12- Project No. 544-2093 02-07-445 1997 UNIFORM BUILDING CODE SEISMIC DESIGN INFORMATION The International Conference of Building Officials 1997 Uniform Building Code contains substantial revisions and additions to the earthquake engineering section in Chapter 16. Concepts contained in the code that will be relevant to construction of the proposed structures are summarized below. Ground shaking is expected to be the primary hazard most likely to affect the site, based upon proximity to significant faults capable of generating large earthquakes. Major fault zones considered to be most likely to create strong ground shaking at the site are listed below, Approximate Distance Fault Type I _ Fault Zone From Site_ (1997 UBQ San Andreas T__ _ 15 km _�_ A _ San Jacinto 27.5 km i A I Based on our field observations and understanding of local geologic conditions, the soil profile type I judged applicable to this site is SD, generally described as stiff or dense soil. The site is located within UBC Seismic Zone 4. The following table presents additional coefficients and factors relevant to seismic mitigation for new construction upon adoption of the 1997 code. Near -Source Near -Source ISeismic Seismic 1 Seismic Acceleration Velocity Coefficient Coefficient Source Factor, N, Factor, N C, I C San Andreas 1 1.0 1 1.0 1 0.44Na I 0.64N San Jacinto I l.01 1.0 1 0.44N, _I 0.64N,.