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003610 (SFD) Soil Engineering Report. .... a .. ;. i' WEIR11 EnnineErsAnc. 1731-A WALTER STREET VENTURA, CALIFORNIA 93003 PHONE (805) 642-6727 December. 13, 1984 B -14413-P1 84=12-239 Landmark Land to P. O. Box 1000 La`.Quinta; CA 92253 RE: Proposed. PGA West City of ta. Quintal, Riverside County, _California Presented.here_wtt is our Soil Engineering Report prepared�foc the proposed PGA. West. 'development located near 58-th. Avenue and Madison Street in the City of La Quinta, Riverside County, California.. . This report incorporates the tentative information supplied' our office, and. in accordance with the request, recommendations for generalsite development and foundation design are provided... This report completes our scope .of' services in accordance :with our agreement dated June 27, 1984. Other services which may be required, such as plan review and grading observation are additional services and will be billed according to the Fee Schedule in effect at the -time the services are provided. Please contact the undersigned if there are any questions concerning this report or the recommendations included herein. , Respectfully submitted, BUENA ENGINEERS, INC. Reviewed and approved Richard M. Beard Raymond E. Brannen CE 24552 CE 28966 RMB/REB/is Copies: 6 - Landmark Land 1 - VTA File 2 - PS file BAKERSFIELD t805) 327.5150 VENTURA LANCASTER (805) 642.6727 1 (805) 948.7538 SANTA BARBARA PALM SPRINGS .(805) 966-9912 (714) 328.9131 SAN LUIS QBISPO (805) 544.6187 TABLE OF CONTENTS INTRODUCTION........................................................ 1 SITE SETTING........................................................... 1 FIELD INVESTIGATION...................................................... 2 LABORATORY TESTING .................:........................... 3 SOIL CONDITIONS :...................................... ............. 3 SITE DEVELOPMENT AND GRADING ......................... .:........... 3 Site Grading....4 ........ ........................... 4. Golf Course .. ..:.:.:....... 5 One and -Two -Story. Structures ............... ....... ......:..... •. • • ? Commercial Buildings and Clubhouse .......... . :.. .. ....... 5 ." Resort Hotel . ............. .......................... 6 " Swimming Pools and Spas ...............................................: 6` Miscellaneous Structures ................. .................:......... 7 STRUCTURE DESIGN ......................................................... 7 Foundations ......................................... 7 General Building .................................... ........... ...... 8 Settlement Considerations ............................................. . 8 Frictional and Lateral Coefficients ............................. ...... 8 Slabs -on -Grade ...................................... 9 Slope Stability ............. 9 ........................................ Paving Sections..... ............................... ............. 9 LIMITATIONS AND UNIFORMITY OF CONDITIONS .......................... 9 APPENDIX A Summary of Test Results Table 29-A APPENDIX B Standard Grading Specifications APPENDIX C Site Plan Log of Borings BUENA ENGINEERS, INC. December 13, 1984 -1- INTRODUCTION B -14413-P1 . 84-12-239 This report presents results of a Soil Engineering Study performed for the proposed PGA West development in the City of La Quinta, Riverside County,.California. A. It is our understanding that the .proposed development will. include a variety of structures 'including. single family residences, condominiums, commercial buildings, and a resort ' hotel: Construction types will probably include wood frame and stucco;, concrete tilt -up, masonry, and steel frame buildings: The : exact foundation types or locations of the buildings are not known at this time. B. For single family. residences and condominiums structural considerations for building column loads. of up to 15 kips and a maximum wall loading of 1.5 kips per: lineal foot were used''to as a basis for the recommendations. C. For commercial construction .structural consideration for column loads. of up to 50 kips (dead plus live..load) and a maximum .wall loading, of 3.0 kips per linear foot were used as• a. basis for recommendations. D. For larger structures column loads of up to 150 kips and wall loads of up to 3.0 kips per lineal foot were used as a basis for recommendations. SITE SETTING The site of the proposed development included in this report is bounded by 54th Avenue on the north, Airport Boulevard on the south, Jefferson Street on the west, and Madison Street on the east, in the City of La Quinta, Riverside County, California. A. The site is occupied by a house in the northwest section and a barn toward the middle. B. The site is level and most of the area has been disced for weed control, but much vegetation has regrown. The east portion is presently under cultivation. C. .There does not appear to have been any previous grading, but the lake for the development is presently being excavated. D. No utilities were observed with the exception of a well near the barn. BUENAENGINEERS, INC. December 13, 1984 -2 B -14413-P1 84-12-239 FIELD INVESTIGATION Exploratory borings were drilled and trenches excavated for observing the soil. profile and obtaining samples for further analysis. A. Fourteen (14) borings were drilled and fifteen '(15) trenches wereexcavated for soil profiling and, sampling, to a maximum depth of thirty-one (31) feet below the :existing ground surface... The field work was conducted between November . 13 and 20, 1984 using a CME 45-B drilling rig, a Mobile drilling. rig, and a backhoe. _ B. Samples were secured within the test. borings with a two and 'one-half QW .inch diameter ring sampler (ASTM D 3550;. shoe similar to ASTM' 15-1586). The samples were.. obtained by driving the sampler with a 140..pound hammer, . dropping 30 inches, in accordance with ASTM D 1586. C. Moisture and density were measured -at selected intervals in the backhoe pits in accordance with ASTM 2922-78 and ASTM 3017-78 Nuclear Density. Test. Procedure. D. .-Bulk samples of the soil types encountered were gathered from the auger cuttings and from the spoil of the trench excavations for classification purposes. E... The final logs represent our interpretation of the contents of the .field logs, and the results of the laboratory observations and tests of the field samples. The final logs are included in an appendix of this report. The stratification lines represent the approximate boundaries between soil types and the transition may be gradual. LABORATORY TESTING After a visual and tactile classification in the field, samples were returned to the laboratory, classifications were checked, and a testing program was established. A. Samples were reviewed along with field logs to determine which would be further analyzed. Those chosen were considered representative of soils which would be exposed and/or used in grading and those deemed within building influence. B. In-situ moisture content and unit dry weights for the core samples were developed in accordance with ASTM D 2937. BUENA ENGINEERS, INC. December 13, 1984 -3 B -14413-P1 84-12-239 C. The relative strength characteristics of the subsurface soils were determined from the results of. direct shear tests. Specimens were placed in contact with water at least 24 hours before testing, and were then sheared under normal loads ranging from 0.5 to 2.0 KSF. D: Settlement potential. was evaluated from the results of consolidation test performed in accordance with ASTM D 2435. E. Classification tests consisted of Expansion Index (UBC Standard 29-2), Maximum Density -Optimum Moisture (ASTM D 1557), and hydrometer analysis (California Test Method 203): F: Refer .to Appendix A for tabular and graphic representations of the test results. SOIL CONDITIONS As determined by the borings, site soils were found to consist primarily of sands and ..silts. A. The soils, encountered were pr'imar'ily slightly silty sands and slightly sandy silts. These soils were often highly interbedded . B. Expansion tests indicate soils to be in the "very low" expansion category in accordance with UBC'Table 29-C. C. In general soils were loose throughout the depths investigated although firmer soils were encountered in some areas. D. In general soils were compressible and in some cases susceptible to hydroconsolidation. SITE DEVELOPMENT AND GRADING Prior to any earth moving operations, areas to be graded should be cleaned of vegetation and other deleterious materials. Appendix B, "Standard Grading Specifications" contains specific suggestions for removal and disposal of deleterious substances and, as such, forms.'a part* of these Site Development and Grading Recommendations. BUENA ENGINEERS, INC. December 13, 1984 -4- B-14413-P1 84-12-239 Site Grading A.. General - Grading 1. Consolidation tests and in-place densities show a Varying potential for settlement and an adverse effect of adding .moisture. The consolidation rests indicate a susceptibility to water at. the in-situ conditions. Therefore, recompaction of the bearing.soils is recommended. 2. The existing ground surface. should be initially prepared for grading by removing vegetation, noncomplying_ fill' or other 'incompetent material. No compacted fill .should be placed .unless the underlying soil has been observed by the soil engineer: - 3. Previously removed soils, once cleaned of rocks larger than eight (8) inched in greatest dimension,..and. other deleterious material, may be placed in thin layers and mechanically compacted back to finish grade. . 4:. Fill and backfill should be compactedto the minimums of ninety and ninety-five percent '-of maximum dry density obtainable.by:the ASTM D 1557 test method, modified to three layers as specified below. Specific requirements are included in Appendix B,""Standard Grading. Specifications" and Chapter 70 of the Uniform Building Code. 5: It is anticipated that during grading a loss of approximately two tenths of a foot due to stripping; and a shrinkage factor of fifteen percent (15%) to twenty percent (20%) for the upper five (5) feet of soil may be used for quantity calculations. This is based on compactive effort needed to produce an average degree of compaction of approximately 93 to 94 percent, and may vary depending on contractor methods. Subsidence is extimated at between two-tenths to three -tenths of a foot. 6..-,-, Areas around the -structures should be graded so that drainage is positive and away from the structures. Gutters and down spouts should be used to. convey water out of the foundation area. 7. It is recommended that the soil and foundation engineer be retained to provide soil engineering services during construction of the excavation and foundation phases of the work. This is to observe compliance with the design concepts, specification and recommendations and 'to allow design changes. in the event that subsurface conditions differ from these anticipated prior to start of construction. BUENA ENGINEERS, INC. ...'December 13, 1984 B. D. -5- B-14413-P1 184-12-239 Golf Course 1. In the golf course areas, the areas to receive fill, after being cleared of organics and other foreign materials, should be scarified, moisture .conditioned and the surface compacted, using heavy vibrating equipment, to a* minimum of eighty-five percent (85%) of maximum density. Fill materials should be placed in thin layers, moistened to near optimum and then compacted to a minimum of ninety percent of maximum density. 2... In cut areas the finishedgrade should be scarified moistened to near :optimum and' then compacted, using vibrating equipment, to: at least eighty. -five percent (85%) of maximum density. One. and Two Story. Structures (Wood frame and Stucco) 1. Areas. to receive three feet or more fill should be prepared byover- excavating to a depth. of three feet below original grade. The- exposed surface should be compacted. by means. of heavy vibrating equipment so that .the upper one foot is at least ninety-five percent (95%) of maximum density. Fill material should then be placed in thin layers: at near optimum moisture and' compacted to a minimum of ninety. percent of ' maximum density. 2. Areas that are to receive less than three feet of fill, and areas in. cut, should be undercut to a depth of four feet below finished -grade. The exposed surface should be compacted by means of heavy vibrating equipment so that the upper one foot is at least ninety-five (95%) of maximum density. Fill material should then be placed in thin layers at near optimum moisture. and compacted to a minimum of ninety percent of maximum density. 3. These grading requirements apply to building areas and at least five feet beyond building limits. Commercial Buildings and Clubhouse 1. Soils within the. building area and at least ten feet beyond the . building limits should be removed to a minimum of three feet below present grade or five feet below the bottom of the footings, whichever is lower. BUENA ENGINEERS, INC. December 13, 1984 -6- B -14413-P1 84-12-239 The exposed surface should be compacted by means of heavy vibrating equipment so that the upper one foot is at least ninety-five percent (95%) of maximum density. Fill material may then be placed in thin layers at near optimum moisture and compacted to . a minimum of ninety-five percent (95%) of maximum density.. E. ResortHotel 1. Bearing -soils should be removed: to a depth equal to twice the footing width, for grade beams, continuous, or pad footings. The exposed surface should be compacted to a minimum. of ninety-five percent (95%) of maximum density. Fill may then be: placed in .thin layers at near optimum moisture and` compacted to a minimum of ninety-five percent (95%) of maximum density. 2.- Slab areas should be over -excavated two feet below slab subgrade. The exposed surface should -'be molstened'so that at least optimum moisture is obtained to a depth:. three feet below the exposed surface and then compacted to a minimum of ninety-five percent (95%) of maximum density. Fill may then be placed in. thin layers at or near optimum moisture and compacted to at least ninety five percent (95%) of maximum density. 3. Alternatively, heavier loads. may. be carried on piling. Recommendations regarding piles can be provided as required. F. Swimming -Pools and Spas I., Where swimming pools and spas are bottomed below the depth of compaction it is recommended that the pool and. spa excavation be deepened two additional feet. The exposed surface should be scarified, moisture conditioned and be recompacted. Previously removed soils may then be recompacted up to the bottom of the pool or spa. BUENA ENGINEERS, INC. December 13, 1984 -7- B -14413-P1. 84-12-239 G. Miscellaneous Structures 1. Preparing the areas for miscellaneous structures such as foot bridges, entrance posts, sign foundations etc.,. shall compaction as noted for single story structures except that density of the upper one foot can be limited to a minimum of ninety percent of maximum density. STRUCTURE DESIGN X. Foundations Conventional continuous footings and/or. isolated pad footings may be used for support of structures. 1: All pad and continuous. footings. or load bearing grade, beams should be founded on firm compacted soil as recommended elsewhere in this report. ' 2:. A minimum: footing depth of twelve inches (12") below lowest adjacent finish grade should be maintained for one story structures and eighteen (18) inches below lowest adjacent grade should be maintained for two story structures. 3. Continuous foundations satisfying the above conditions may be designed for the following values assuming a twelve .(12) inch deep one (1) foot wide footing: 1100 psf, for dead plus reasonable live load: 1470 psf when wind and seismic forces are included. 4. Pad foundations satisfying the above conditions may be designed for the following values assuming a three by three.(3 x 3) foot by eighteen (18) inch deep footing: 1500 psf for dead plus reasonable. live load. 2000 psf when wind and seismic forces are included. 5. The above dead plus live load value may be increased by 150 psf for each additional six (6) inches of depth and by 100. psf for each additional foot of width. 6. Allowable bearing values for dead plus live loads may be increased by one- third when wind and se.ismic forces are included. BUENA ENGINEERS, INC. December 13, 1984 C. -8- . B -14413-P1 84-12-239' 7. Table 29-A gives specific minimum requirements .for width, depth and reinforcing. Other requirements may be more stringent and would govern. 8. Lateral loads may be resisted by soil friction on floor slabs and foundations and by passive resistance of the soils acting on foundation stem walls. Lateral capacity is based partially on the assumption that any required backfill adjacent to foundations and grade beams is properly compacted. General .Building 1. Foundation .excavations , should be visually observed by the soil...engirieer during excavation and prior. to placement of reinforcing. steel or concrete. Local variations in conditions may warrant deepening of footings. 2. _ Allowable bearing values are net (weight of. footing and soil surcharge may he neglectedY and .are applicable for dead plus reasonable live loads. Settlement Considerations 1. Expected maxibrium settlement of less .than one (1) inch is anticipated for. foundations and floor slabs designed and placed on recompac ted soil as.. recommended: 2. Differential settlement between adjacent load bearing members is .i anticipated to be less than one-half (!4) inch. 3. The majority. of anticipated settlements should occur during construction with post construction settlement being minimal. D. Frictional and Lateral Coefficients 1.. Resistance to lateral loading may be provided by friction acting on the base of foundations. A coefficient of friction of 0.48 may be applied to dead load forces. 2. Passive resistance acting on the sides of foundation stems (290 pcf, equivalent fluid weight), may be included for resistance to lateral load. 3. A one-third (1/3) increase in the quoted passive value may be used for wind or seismic loads. 4. When passive resistance of soils against grade beams and the frictional resistance between the floor. slabs and the supporting soils are combined, the friction factor should be reduced to 0.32 of dead load forces. BUENA"ENGINEERS, INC. December 13, 1984 -9- B -14413-P1 8.4-12-239 5. For retaining walls backfilled with compacted native soil, a pressure of an equivalent fluid weighing 35 pcf may be used for well. drained, level backfill conditions, plus the effect of any surcharge loads. . E. Slabs -on -Grade . L. Concrete slabs -on -grade should be supported by firm compacted soil placed in accordance with applicable'sections of this .report. 2. Slabs on grade should. be reinforcedwith 6X6 No.10/No.10 welded wire fabric. 3. It is recommended that. perimeter. slabs (sidewalks, patios, etc.) be designed relatively independent of footing stems (free.floating) so settlement and/or expansion should not cause cracking.: 4: Slabs should be underlaid with' an appropriate. vapor barrier in areas where floor wetness would be' undesirable. The membrane .should be covered with two inches. of sand' 'to protect .it .during construction. The sand should be lightly. moistened just prior to placing the concrete. F. Slope Stability 1. Fill slopes may be constructed to the following maximum heights for the stated slope angle.. These angles were developed using Singh's charts as presented in the November 1970, Journal of the Soil Mechanics and Foundations Division of the ASCE: Slope Angle Maximum Height 1-1/2:1 5' 1-3/4:1 2:1 13' Slope heights are primarily limited by the lack of cohesion in the soil. Because of the lack of :cohesion slopes will be highly erodible and will require periodic maintenance or protective ground covers. G. Paving Sections The following paving sections are based on the approximate average "R" value (R=55) measured on samples of subgrade soils sampled along 58th Avenue and BUENA ENGINEERS, INC. -10- B -14413-P1 84-12-239 Madison Street. Final paving sections should be based on "R" values measured on actual subgrade soils sampled at the end of rough grading and actual paving' section may be less or more than those listed below.. Arterial Streets TI = 7' IIRII 55 inches AC on 5 inches Class II Base or.2.inches AC on 7 inches Class 11 Base Collector Streets . - TI=6 ..R,.=55 Use 3 inches AC on 314 inches Class 11 Base or 2 inches AC on 514 inches Class II Base Residential Streets. TI = 5 IIRII 55 Use 2inches AC on 314 inches Class II Base Drives subjected to light truck traffic (trash trucks, delivery trucks) TI = 5 IIRII = 55 Use 2.inches AC on 314 inches Class II Base Parking Areas TI . 4 "R" = 55 Use 2 inches AC on 2 inches Class Il Base or 3 inches AC on native. -11 B -14413-P1 84-12-239 LIMITATIONS AND UNIFORMITY OF CONDITIONS The analysis and recommendations submitted in this report are based in part upon the data obtained from the fourteen (14) borings drilled and fifteen (15) trenches excavated on this site and on experience and .judgement. The nature and extent of variations between the borings may not become evident until construction. If variations then appear evident, it will be necessaryto reevaluate the recommendations of this. report. Findings of this report are valid as of this date; however, changes in conditions 'of 'a property, can occur with. passage of time whether.they be due to natural processes or. works of man on this or adjacent properties In addition, changes in applicable or appropriate' standards. occur whether they result. from legislation - or broadening ` of knowledge. Accordingly, findings of..this report may be. invalidated wholly or partially . by changes outside our control. Therefore, this report is subject to review and should not a relied upon after a period of one year.- .In ear: In the event that any changes in the nature, desigri or location of the development .or buildings are planned, the conclusions. and recommendations contained in this report shall not be considered valid unless the changes are reviewed and conclusions of this report modified or verified in writing. This report is issued with the understanding that it is the responsibility of the owner, or of his representative to insure that the information and recommendations contained herein are called to the attention of the architect and engineers for 'the project and incorporated into the plan and that the necessary steps are taken to see that the contractor and subcontractors carry out such recommendations in the field. The soil engineer has prepared this report for the exclusive. use of the client and authorized agents. This report has been prepared in accordance with generally accepted soil and foundation engineering practices. No other warranties either expressed or implied are made as to the professional advice provided under the teams of this agreement, and included in the report. BUENA ENGINEERS, INC.