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09-1008 (SFD) Geotechnical InvestigationGEOTECHNICAL INVESTIGATION PROPOSED CUSTOM RESIDENCE LOT 25-A 'I'1-:I.E MADISON CLUB LA QUINTA, CALIFORNIA prepared By- Sladden Engineering 77-725 Enfield Lane, Suite 100 Palm Desert, California 92211 (760) 772-3893 FH� OC�T � 2009 ke . r f. GEOTECHNICAL INVESTIGATION PROPOSED CUSTOM RESIDENCE LOT 25-A 'I'1-:I.E MADISON CLUB LA QUINTA, CALIFORNIA prepared By- Sladden Engineering 77-725 Enfield Lane, Suite 100 Palm Desert, California 92211 (760) 772-3893 FH� OC�T � 2009 ke . r Sladden Engineering 77-725 Enfield Lane, Suite 100, Palm Desert, CA 92211 (760) 772-3893 Fax (760) 772-389,5 6782 Stanton Avc., Suite A. Bucna Park, CA 90621 (714) 523-0952 Fax (714) 523-1369 450 Egan Avenue, Beaumont, CA 92223 (951) 845.7743 Fax (951) 845-8863 June 25, 2008 Cox, Castle, & Nicholson, I:,LP 2049 Century .Park East, 28th Floor Los Angeles, California 90067 Attention: Mr. John Nicholson -Project: Proposed Custom Residence The Madison Club, Lot 25-A La Quinta, California Subject: Geotechnical Investigation Project No. 544-08147 08-06-348 Presented herewith is the report of our Geotechnical Investigation conducted for the construction of the prupused single-family residence to be located on Lot 25-A within The Madison Club developtinent'tn'the City of La Quinta, California. The investigation was performed to provide recommendations for''site preparation and to assist in foundation design for the proposed residential structure and the related site improvements. This report presents the results of our field investigation and laboratory tests along with conclusions and recommendations for foundation design and site preparation. This report completes our original scope of services as outlined within our proposal dated June 10, 2008. We -appreciate the opportunity to provide service to you on this project. 'If you have any questions regarding, this report, please contact the undersigned �1 Respectfully submitted, SLADDEN ENGINEERING Nicholas S. Devlin Engineer SER/nd Copies: 6/Cox, Castle, & Nicholson, LLP Brett L. Anderson Principal Engineer L. No. C 45380 C 45389 ) "S 92010 GEOTECHNICAL INVESTIGATION CUSTOM RESIDENCE LOT 25-A THE MADISON CLUB LA QUINTA, CALIFORNIA June 25, 2008 TABLE OF CONTENTS INTRODUCTION................................................................... SCOPE, OF WORK ........................... PROTECT DESCRIPTION .................... 1 GEOLOGY AND SEISMICII'Y.......................................................................................................... 1 2007 California Building Code (CI3C) Seismic Design Parameters ................ 2 SUBSURFACE, CONDITIONS ................ ... LIQUEFACTION..........................................................................................................................,............ 3 CONCLUSIONS AND RECOMMENDATIONS................................................ 4 Foundation Design........................................................................... ......................... 4 Settlement ........4 ............... 5 Lateral Design ........................... ........... ........... ................... ..: Retaining Walls...................................................................................................... S Expansive Soil............................................................................................. 5 ConcreteSlabs-on-Grade................................................................................. ........................... 6 Soluble Sulfates ..................... 6 Shrinkage and Subsidence.................................................................................................... General Site Grading...................................................................................................................... 6 6 I. Site Clearing...... I ... I.............................................................. 6 2. Preparation of Basement Areas ..................... ..... 3. Preparation of At Grade Building and Foundation Areas ...................... ...................... 7 4'. Placement of Compacted Fill ................................................... . 5. Preparation of Slab and Pavement Areas .............. 7 6. Tests and Inspection............................................................... GENE12A............ 7 L REFFRENCES...................................................................... . .....................:................................ 8 ........................................................................ 9 APPENDIX A - Site Plan and Bore Logs Field Exploration APPENDIX B - Laboratory Tests Laboratory Test Results APPENDIX C - Seismic Hazards Map Seismic Analyses Output Data APPENDIX D - Retaining Wall Seismic Load Analyses June 25, 2008 -1- Project No. 544-08'147 08-06-348 INTRODUCTION This report presents the results of our Geotechnical Investigation performed to provide specific recommendations for site preparation and to assist in the design and construction of the foundations for the proposed residential structure. The project site is located on Lot 25-A within The Madison Club development in the City of La Quinta, Califomia, The preliminary plans indicate that the proposed project will include a single-family residence with a partial basement area along with various associated site improvements. The associated site improvements are expected to include a swimming pool, concrete walkways, patios, driveways, and pool decking, underground utilities, and landscape areas. This report is intended to, supplement the geotechnical reports previously prepared for the Madison Golf Club development. SCOPE OF WORK The purpose of our investigation was to determine certain engineering characteristics of the near surface soil on the site to develop recommendations for foundation design and site preparation. Our investigation included previous report review, field exploration, Iaboratory tests, literature review, engineering analysis and the preparation of this report. Evaluation of hazardous materials or other, environmental concerns was not within the scope of services provided. Our investigation was performed in accordance with contemporary geotechnical engineering principles and practice. We do not make other warranty, either express or implied. PROJECT DESCRIPTION The project site is located on Lot 25-A within The Madison Club development in the City of La Quinta, California. It is our understanding that the project will consist of a single-family residence along with various associated site improvements. It is our understanding that the proposed residential structure will be of relatively lightweight wood -frame construction and will be supported by conventional shallow spread footings and concrete slabs on grade. The associated improvements will include.a swimming pool, concrete walkways, driveways, pool decking, and patios, landscape areas and various underground utilities. The majority of the subject site is presently vacant and the lot has been previously graded during construction of the surrounding Madison Club residential development and golf course. The ground surface is covered with dry turf. The adjacent lot south of the site is currently vacant. Ross Avenue forms 'the eastern site boundary and a cart path forms the northern site boundary. The property is level throughout and is near the elevation of the adjacent properties and roadways. The existing golf course forms the western site boundary. There are underground utilities along the existing roadways and servicing the adjacent lots. , Based upon our previous experience with lightweight structures, we expect that isolated column loads will be less than 50 kips and wall loading will be less than to 5.0 kips per linear foot. Grading is expected to include minor cuts and fills to match the nearby elevations to accommodate site drainage. This does not include excavation of the partial basement area and removal and recompaction of the bearing soil 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. Sladden Engineering. June 25, 2008 _z - Project No. 544-08147 08-06-348 GEOLOGY AND SEISMICITY The project site is located within the central Coachella Valley that is part of the broader Salton Trough geomorphic province. The Salton Trough is a northwest trending depression that extends from tl lc .Gulf of California to the Banning Pass. Structurally the Salton Trough is dominated by several northwest trending faults, most notable of that is the San Andreas system. A relatively thick sequence of sedimentary rock has been deposited in the Coachella Valley portion of the Salton Trough from Miocene to present times. The sediments are predominately terrestrial in nature with some lacustrian and minor marine deposits. The mountains surrounding the Coachella Valley are composed primarily of Precambrian metamorphic and Mesozoic granitic rock. The Coachella Valley is situated in one of the more seismically active areas of California, The San Andreas Fault zone is considered capable of generating a.maximum credible earthquake of magnitude 8.0 and because of its proximity to the project site it should be considered in design fault for the project. Based on our review of published and unpublished geotechnical maps and literature pertaining to site, the San Andreas (Southern) Fault (approximately 10.0 kilometers or 6.6 miles to the northeast of the site) would probably generate the most severe site ground motions with an anticipated maximum moment magnitude (M.y) of 7.4. In addition to the San Andreas (Southern) Fault, the San Jacinto (Anna) Fault presents a ground rupture hazard and is Ideated approximately 31.6 kilometers or 19.6 miles to the southwest of the site with an anticipated maximum moment magnitude (M.y) of 7.2, The site has been subjected to past ground shaking by faults that traverse through the region. Strong seismic shaking from nearby active faults is expected to produce strong seismic shaking during the design life of the proposed project. A probabilistic approach was employed to the estimate ,the peak ground acceleration (amax) that could be experienced at the site. Based on the USGS Probable..Kazard Curves (USGS, 2008) the site could be subjected to ground accelerations on the order of 0.53 percent gravity (%g). The peak ground acceleration at the site is judged to have a 475 year return period and a 10 percent chance of exceedence in 50 years. 2007 California Building Code (CBC): According to the 2007 CBC every structure, and portion thereof, including non-structural components that are permanently attached to structures and their supports and attachments, shall be designed and constructed to resist the effects of earthquake motions in accordance With ASCE7 (ASCE, 2006), excluding Chapter 14 and Appendix 11A. The seismic design category for a structure may be determined in accordance with Section 1613 of the 2006 IBC or ASCE7. According to the 2006 IBC, Site Class D may be used to estimate design seismic loading for the proposed structure. The period of the structure should be less than Iii second. This assumption should be verified by the project structural engineer. The 2007 CBC Seismic Design Parameters are summarized below. Occupancy Category (Table 1604.5): it Site Class (Table 1613.5.5): D Ss (Figure 1613.5(3)): 1.500g S1 (Figure 7.613.5(4)): 0.6008 Fa (Table 1613.5.3(1)):1.0 Fv (Table 1613.5,3(2)):1.5 Sladden Engineering .)une 25, 2008 -3- Project No. 544-08147 08-06-348 Suis (Equation 16-37 (Fa X Ssl):1.50og Sml. (Equation 16-38 Tv X SID: 0.900g SDs (Equation 16-39 12/3 X Sins)): 1.000g SW (Equation 16-4012/3 X Sm7 }): 0.600g Seismic Design Category based on SDs ('fable 1613.5.6(1)): D Seismic Design Category based on SDI (Table 1613.5.6(2)): D The site is not located in any Earthquake Fault zones as designated by the State but is mapped in the County's Liquefaction and Cround Shaking Hazard Zone V. Several significant seismic events have occurred within the Coachella Valley during the past 50 years. The events include Desert Hot Springs - 1948 (6.5 Magnitude), Palm Springs - 1986 (5.9 Magnitude), Desert Hot Springs - 1992 (6.1 Magnitude), Landers -1992 (7.5 Magnitude) and Big Bear - 1992 (6.6 Magnitude). SUBSUI(FACE CONDITIONS The soil underlying the site consists primarily of engineered fill soil overlying native fine-grained silty sand with scattered thin interbedded sandy silt and silty clay layers. The surface soil consists of engineered fills placed during the previous rough grading. Silty sand was the most prominent soil within our exploratory bores but several relatively,thin sandy silt layers were also encountered. The engineered fill and native soil encountered near the existing ground surface appeared dense but some of the underlying native silty sand and sandy silt layers appeared somewhat loose. Relatively undisturbed samples indicated'dry density varying from 92.0 to 1252 pcf.. Sampler penetration resistance (as measured by field blowcounts) indicates dense conditions within the surface fill soil and that density generally increases with depth within the underlying native soil. The site soil was dry on the surface anis moist below a depth of approximately 5 feet and the silty layers were typically moist. Laboratory tests indicated moisture content varying from 0.8 to 16.4 percent. Laboratory tests indicate that the surface soil consists primarily of silty sand. Expansion tests indicate that the surface silty sand is generally non -expansive and is classified as "very low' expansion category soil in accordance with 2007 CBC standards. Croundwater was not encountered within our bores that extended to depths of approximately 51 feet below the existing ground surface. Groundwater should not be a factor in design and construction. LIQUEFACTION Uquefaction occurs with sudden loss of soil strength because of rapid increases in pore pressures within cohesionless soil as a result of repeated cyclic loading during seismic events. Several conditions must be present for liquefaction to occur including, the presence of relatively shallow groundwater_ generally loose soil conditions, the susceptibility of soil to liquefaction based upon grain -size characteristics and the generation of significant and repeated seismically induced ground accelerations. Liquefaction affects primarily loose, uniform grained cohesionless sand with low relative densities. Sladden Engineering June 25, 2008 -4_ Project No. 544-081.47 08-06-348 In the case of this project site, several of the factors required for liquefaction to occur are absent. As previously indicated; groundwater was not encountered within our exploratory bores that extended to a maximum depth of approximately 51 feet below the existing ground surface on the site. Because of the surface -to -groundwater depth, specific liquefaction analyses were not performed. Based upon the surface -to -groundwater depth, the potential for liquefaction and related surficial affects of liquefaction impacting the site are considered negligible. CONCLUSIONS AND RECOMMENDATIONS Based upon our field investigation and laboratory tests, it is our opinion that the proposed single-family residence 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. Because the lot has been previously rough graded, the remedial grading recommended at this time expected to be is limited to the possible subterranean levels as well as the swimming pool/outdoor living area. We recommend that remedial grading within the proposed building areas include overexeavation and reeompaction of the primary bearing soil within the basement areas and the weathered surface soil within the at grade portions of the residence. Specific recommendations for site preparation are presented in the Site Grading section of this report. As previously stated, groundwater was not encountered within our bores and groundwater is in excess of. 50 feet below the existing ground surface in the vicinity of the site. Because of the surface -to - groundwater depth, specific liquefaction analyses were not performed. Based upon the surface -to - groundwater depth, the potential for liquefaction and related surficial affects of liquefaction impacting the site are considered negligible. The site is located in one of the more seismically active areas in California. Design professionals should be aware of the site setting and the potential for earthquake activity during the anticipated life of the structure should be acknowledged. The accelerations that may be experienced on the site (as previously discussed) should be considered in design. The seismic provisions included in the 2007 CBC should be considered the minimum design criteria. Caving did occur within our bores and the potential for caving should be expected within deeper excavations. All excavations should be constructed in accordance with the normal CalOS14A excavation criteria: On the basis of our observations of the materials encountered, we anticipate that the near surface silty sand will be classified by CalOSI-iA as Type C. Soil conditions should be verified in the field by a "Competent person" employed by the Contractor. The near surface soil encountered during our investigation was found to be non -expansive. Laboratory tests indicated an 'Expansion Index of 15 for the surface silty sand that corresponds with the "very low" expansion category in accordance with 2007 CBC standards. Sladden Engineering June 25, 2008 5- Project No. 544-08W 08-06-348 The following recommendations present more detailed design, criteria that have been developed on the basis of our field and laboratory investigation. The recommendations are based upon non -expansive soil criteria. Foundation Design: The results of our investigation indicate that either conventional shallow continuous footings or isolated pad footings that are supported upon properly compacted soil, may be expected to provide adequate support for the proposed residential structure foundations. Building pad grading should be performed as described in the Site Grading Section of this report to provide for uniform and firm bearing conditions for the structure foundations. Footings should extend at least 12 inches beneath lowest adjacent grade. Isolated square or rectangular footings should be at least two feet square and continuous footings should be at least 12 inches wide. Continuous footings may be designed using an allowable bearing value of 1500 pounds per square foot (psf) and isolated pad footings may be designed using an allowable bearing pressure of 1800 psf. Allowable increases of 300 psf for each additional 1 foot of width and 300 psf for each additional 6 inches of depth may be utilized if desired. The maximum allowable bearing pressure should be 3000 psf. The allowable bearing pressures are applicable to dead and frequently applied live loads. The allowable bearing pressures may be increased by 1/3 to resist wind and seismic loading. Care should be taken to see that bearing or subgrade soil is not allowed to become saturated from the ponding of rainwater or irrigation. Drainage from the building area should be rapid and complete. The recommendations provided in the preceding paragraph are based on the assumption that all footings will be supported upon properly compacted engineered fill soil. All grading should be performed under the tests and inspection of the Soil 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. Settlement: Settlement resulting from the anticipated foundation loads should be.minimal provided that the recommendations included in this report are considered in foundation design and construction. The ultimate settlement is estimated to be approximately 1 inch when using the recommended bearing values. As a practical matter, differential settlement between footings On 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 0.40 between soil and concrete may be used with consideration to dead load forces only. A passive earth pressure of 250 pounds per square foot, per foot of depth, may be used for the sides of footings that are poured against properly compacted native or approved non -expansive import soil. Passive earth pressure should be ignored within the upper I foot except where confined (such as beneath a floor slab). Sladden Engineering June 25, 2008 :6- Project No. 544-083.47 08-06-348 Retaining Walls: Retaining walls may be necessary to accomplish the proposed construction. Lateral pressures for use in retaining wall design can be estimated using an equivalent 'fluid weight of 35 pcf for level free -draining native backfill conditions. For walls that are to be restrained at the top such as the basement walls, the equivalent fluid weight should be increased to 55 pcf for level free -draining native backfill conditions. Backdrains should be provided for the full height of the walls. Seismic Conditions- A "seismic' pressure of 3.2 kips/ft acting at a distance of OAH (H = height of the wall in feet) from the bottom of the wall for drained level native backfill soil may be utilized for the design of earth retaining walls. A detailed summary of our retaining wall loading calculations is in included within Appendix D of this report. ExpansiveSoil: Because of the prominence of "very low" expansion category soil near the surface, the expansion' potential of the foundation bearing soil should not be a'controlling factor in foundation or floor slab design. Expansion potential should be reevaluated subsequent'ty' grading. Concrete Slabs -on -Grade: All surfaces to receive concrete slabs-on=grade should be underlain by a Minimum compacted non -expansive fill thickness of 24 inches, placed as described in- the Site Grading Section of this report. Where slabs arc to receive. moisture sensitive floor coverings or where dampness of the floor, slab is not desired, we recommend the use of an appropriate vapor retarder or an adequate capillary break, Vapor retarders should be protected by sand on top -and bottom -to "reduce the possibility of puncture and to aid in obtaining uniform concrete curing, Reinforcement of slabs -on -grade to ,resist expansive soil pressures should not be necessary. However, reinforcement will have a beneficial effect in containing cracking because of 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 soil have'been determined to be 1,200 ppm that is considered to be potentially corrosive with respect to concrete. The use of Type V cement and specialized sulfate resistant concrete mix designs may be necessary for concrete in contact with the native soil. Sulfate concentrations should be reevaluated after subsequent grading. Shrinkage and Subsidence; Volumetric shrinkage of the material that is excavated and replaced as controlled compacted fill should be anticipated. Because the surface soil consists of compact engineered fill, we expect that shrinkage should be less than 10 percent. Subsidence of the surfaces that are scarified and compacted should be less than 1 tenth 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. The values for shrinkage and subsidence are exclusive of losses that will occur because of the stripping of the organic material from the surface and the removal of unsuitable material. gladden Engineering June 25, 2008 -7_ Project No. 544408147 08-06-3.48 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 tests and are intended to provide a uniform compacted mat of soil beneath the building slabs and foundations. Z. Site Clearing: Proper site clearing will be very important. The existing vegetation abandoned irrigation lines should be removed from the proposed building areas and the resulting excavations should be properly backfilled. Soil that is disturbed during site clearing should be removed and replaced as controlled compacted fill under the direction of the Soil Engineer. 2. Preparation of Basement Areas: In order to provide adequate and uniform bearing conditions, we recommend overexcavation and recompaction throughout the basement areas. The basement areas should be overexcavated to a depth of at least 3 feet below the bottom of the footings. The exposed soil should then be scarified to a depth of at least 1 foot, moisture conditioned and recompacted to at least 90 percent relative compaction. The excavated material may then be replaced as engineered fill material as recommended in item 4, below. 3. Preparation of At -Grade Building. and Foundation Areas: The weathered surface soil should be scarified to a depth of at least 1. foot moisture conditioned and recompaeted to at least 90 percent relative compaction. The excavated material may then be replaced as I fill material as recommended below. 4. Placement of Compacted Fill: Within the building pad areas, any new fill material should be spread in thin lifts, at near optimum moisture content and compacted to a minimum of 90 percent relative compaction. Imported fill material shall have an Expansion Index not exceeding 20. The contractor shall notify the Soil Engineer at least 48 hours in advance of importing soil 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 Soil Engineer will be based upon material delivered to the site and not the preliminary evaluation of import sources. Our observations of the'materials encountered during our investigation indicate that compaction within the native soil will be most readily obtained by means of heavy rubber tired equipment and/or sheepsfooi compactors. The moisture content of the near surface soil was somewhat inconsistent within our bores. In general, the sandy soil is dry and well below optimum moisture content but some of the deeper silt layers were wet. It is likely that wet silt/clay layers will be encountered during grading particvlarly'in irrigated areas where deep cuts are planned, A uniform and near optimum moisture content should be maintained during fill placement and compaction. Sladden Engineering June 25, 2008 -8- Project No. 544=08147 08-06-348 5. Preparation of Slab and Paving Areas: All surfaces to receive asphalt concrete paving or exterior concrete slabs -on -grade, should be underlain by a minimum compacted fill thickness of 12 inches. This may be accomplished by a combination of overexcavation, scarification and recompaction of the surface, and replacement of the excavated material as controlled' compacted fill. Compaction of the slab and pavement areas should be to a minimum of 90 percent relative compaction, 6. Tests and Inspection: During grading tests and observations should be performed by the Soil Engineer or his representative to verify that the grading is being performed in accordance with the project specifications. Field density tests _shall be performed in accordance with applicable ASTM test standards. The minimum acceptable degree of compaction shall be 90 percent of the maximum dry density as obtained by the ASTM. D1.557-02 test method. Where tests indicate insufficient density, additional compactive effort shall be applied until. retests indicate satisfactory Compaction. GENERAL Tlu, findings and recommendations presented in this report are based upon an interpolation of the soil conditions between bore locations and extrapolation of the 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 Cox, Castle, & Nicholson, LLP 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 operations by a representative of Sladden Engineering. All reeommendations' arc considered to be tentative pending our review of the grading operations and additional tests, if indicated. if others are employed to perform any soil tests, this office should be notified prior to such tests to coordinate any required site visits by our representative and to assure indemnification of Sladden Engineering. We recommend that 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. Sladden Engineering June 25, 2008 -9- Project No. 544-08147 08-06-348 REFERENCES ASC -8 Journal of Geotechnical Engineering Division, April 1974. Boore, Joyner and Fumal (1994) Estimation of Response Spectra and Peak Accelenitions from North American Earthquakes, U. S. Geological Survey, Open File Reports 94-127 and 93-509. Finn, W. E. Liam, (1996) Evaluation <f Liquefaction Potential for Different Earthquake Magnitudes arid Site Conditions, National Center for Earthquake Engineering Research Committee. Joyner and Boore, (1988) Measurements, Characterization and Prediction of Strong Ground Motion, ASCF. Journal of Geotechnical Engineering, Special Publication No. 20. Led & Aibaisa (1974) `'Earthquake Induced Settlement in Saturated Sands". Seed and Idriss (1982) Ground Motions and Soil Liquefaction During Earthquakes, Earthquake Engineering Research Institute Monograph. Seed, Tokimatsu, Harder and Chung, (1985), Influence of SPT procedures in Soil Liquefaction Resistance Evaluations, ASCE journal of Geotechnical Engineering, Volume 111, No. 12, December. Rogers, Thomas 1-I., Geologic Map of California, Santa Ana Map Sheet. Riverside County, 1984, Seismic Safety Element of the Riverside County General Plait Sladden Engineering APPENDIX A Site Plan Bore Logs APPENDIX A FIELD EXPLORATION For our field investigation, 4 exploratory bores were excavated on June 12, 2008 using a truck mounted hollow stem auger rig (Mobile B-61) in the approximate locations indicated on the site plan included in this' appendix; Continuous logs of- the materials encountered were prepared on the site by a representative of Sladden Engineering. Bore logs are included in this appendix. Representative undisturbed samples were obtained within our bore by driving a thin-walled steel , penetration sampler (California split spoon sampler) or a Standard Penetration Test (SPT) sampler with a 140 pound hfammer dropping approximately 30 inches (ASTM D1586), The number of blows required to drive the samplers 18 inches was recorded (generally in 6 inch increments). BlowcoUnts are indicated on the bore log. The California samplers are 3.0 inches in diameter, carrying brass sample rings having inner diameters of 2.5 inches. The standard penetration samplers arc 2.0 inches in diameter with an inner diameter of 1.5 .inches. Undisturbed samples were removed from the sampler and placed in moisture sealed 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 tests. SITE PLAN WITH APPROXIMATE BORE HOLE LOCATIONS — — r 24A � ' 7I.,/.... — mss- f '� �`•. � PA�IGCG 0 / J -. < - ._ . „-. � !' A 1 G 2r2A. V • i 28A �• f % � ! !^aotoa� f i iT! i i, II 1 ! I SCALE: As Shown MAP SOURCE: Client LEGEND JOB NAME: Lot 25A Madison Club ® APPROXIMATE BORE HOLE LOCATION JOB NO. 544-08547 NORTH REPORT NO: 08-06-348 Sladden Engineering Proposed Single -Family Residence Lot 25-A Madison Club, La Quinta Date: 6/12/2008 Bore No. 1. Job Number: 544-08147 g CL � al . Description �, -R A Remarks tificial Fill Soil 10-14 Fcct - 9/17/23 Sandy Silt with Silty Sand: Finc Grained ML 11.75 14.3 52.7 Greyish Brown in color 5 7/13/21 Sandy Silt ML 109.7 16.4 61.0 �cyish Brown in color 10 9/1826 Silty Sand: Finc Graincd and Sandy Silt SM 111.3 13.4 46.3 Greyish Bmwn in Olor 15 61776 Silty Sand: Finc Grainud SM 105.0 6.7 23.8 Light Brown in color v� 20 4/7/8 Silty Sand: Fine Grained and Sandy Silt SM 92.0 7.7 '44.1 Grcyish Brown in color 25 _ ' I 5/7/10 Silty Sand; Finc Grained SM 98.1 9.8 24.1 Gr cyit;h BTUwn in color i 30 518/10 Sandy Silt and Silty Sand: Finc Grained M L 104.4 15.1 52.9 Ycllowisb Brown in color 35 8/8/13 Sandy Silt and Silty Sand: Fine Granted ML 101.2 12.0 53.8 Yellowish Brown in color 40 12/19/19 Sand: Fine Grained 'SP 104.6 3.3 6.3 Light Grey in color Note: 11c stratification lines represent the appiroicimatc 45 ' 14/1621 Sand; Finc Grainod SP 108.6 0.8 10.0 boundarics between the soil (Light. Grcy in color) types; the transition may be - gradual. . Depth = 51 Foet 1 jTotal 50 10/17/18 Silty Sand: Fine Grained SM 106.8 2.5 18.3 laroundwatcr not rncountcrcd - . (Light Grey in color) 18odrock not encountered Sladden Enginccring Proposed Single -Family Rcsidence Lot 25-A Madison Club, La uinta Date:. . 6/12/2008 Bore No. 2 Job Number: 54408147 0 A. 'PI U N pa DescritionCA) a G o Remarks 0 Artificial Fill Soil –10 Feet - 14/20/24 Sandy Silt ML -112.6 15.7 61.3 Greyish Brown in oblor S 3 11/14/22 Silty Sand: Fine Grained and Silt SM 110.8 11.7 40.6 reyish Brown in color 10 11/17/22 Silty Sand: Fine Grained and Sandy Silt SM 117.3 10.5 45.3 reyish Brown in color 15 s, 14/21/22 Silty -Sand! Fine Grained SM 108.1 3.7 12.0 reyish Brown in color I � ' 20 y 8/10/15 Silty Sand: Fine Grained SM 102.2 4.0 15.5 Greyish Brown in color _ � h 25 7/10/14, 1 Silt Sand:.Fine Criiincd SM 102.7 11.0 23.6 ish Brown in color. 30 Cal iforitia Split-Apoon Sample otal Dopth —25 poet Bedrock not 6nuountaod Unrecovered Sample Groundwater not encountered Stiindwtl Pmetrntion 'fest Sainplc 35 40 Note: The stratification Linc, foreseatt the dpproxiritatc - boundaries between the soil types; the transition may be grad ual. 45 50 . Sladden Engineering Proposed Single-family Residence _ . .. Lot 25-A Madison Club, La Quinta Date: 6/12/2008. illare No. 3 Job Number: 544-08147 0 �E a I Dtscri tion . en :9 o Remarks, 0 'l . rtificial Fill Soil --6 Feet - 11/17/19 Silty Sand: Fine Grained and Silt SM 116.7 11.5 42.1 Gicyish Brown in color 5 11/13/17 Silty Sand: Fine Grained and Sandy Silt SM 119.0 11.7 43.4 reyish Brown in color 10 13/19/30 Silly SanJ: Finc Gruinod and Silt SM 114.4 10.7 40.3 Grcyish Brown iii color 15 _ y, ' 1 1820/22 Silty Sand: Finc Graincd SM 107.7 2.8 16.6 Light Grey in color 20 7/11112 Sandy Silt ML 97,5 9.6 61.4 YcIlowish Brown in color 25 :: 5/7/12. . Sand: Finc Giainod SP 99.8 3.1 6.0 11YOlowish Biown in cold 30 Califotnia Split -spoon Sample Total Depth =-25 Feet edrmk not encountered - - Unrixovcrcd Sample I Groundwater not encountered - Standard Penetration Tcst Sample 35 40 Note: The stratification lines reprme nt the appioximatc - bciundarics btxwccn the soil types; the transition may be _ gradual 45 , 50 -- 1 Sladdcn Engineering Proposed. Single -Family Residence Cot 25-A Madison Club, La Quinta VAtc:. 6/12/2008 Bore No. 4 Job Number:, 544 -0 g A- .. Ch . U.. Description . r;, Remark. 0 Is Artificial Fill Soil –5 poet - 13/22/23 Silty Sand: Fine Grained SM 111.0 13.8 29.1 Dark Ycllowish Brown , 5 8/14120 Silty Sand: Fine Grained SM 113.5 15.4 31.9 Dark Yellowish Brown 10 1426/30 Sanely Silt ML 125,5 12.3 50:3 Grcyish Brown in color 15 i 14/23/40 Silty Sand: Fine Grained SM 106.5 3.8 19.3 Greyish Brown in color i 20 8/10/14 Silty Sand: Fine Grained SM 95.8 6.6 39,4 Ycllowish Brown in color - I 25 979110 Sill Sand: Fine Gruincd SM 106.1 13.3 33.2 jriqi,h Brown in color 30 California Split -spoon Sample Total Dcpth —25 Feet • Bedrock not encountered • Unrecovered Sanple Groundwater not encountered - Sandi" Pcnet'nAtion 1r4*t Snrriplc 35 40 Note: The stralificaiiim IincZ mprWimt the appruximutc boundaries between the soil types; the transition may be E 45 50 Sladden Engineering I wo SP SM ML CL GM/GC Caldiimia Splil-Spoon Sample I Unnxovcrod Samplc Standard Penctration Test (SPT) Sample Sladden Enginccring u APPENDIX B Laboratory Tests Laboratory Test Results APPENDIX B LABORATORY TESTS Representative bulk and relatively undisturbed soil samples were obtained in the field and returned to our laboratory for additional observations and tests. Laboratory tests were generally performed in two phases. Me first phase consisted of tests to determine the compaction of the existing natural soil and the general engineering classifications of the soil underlying the site. These tests were performed to estimate the engineering characteristics of the soil and to serve as a basis for selecting samples for the second phase of tests. The second phase consisted of soil mechanics tests. These tests include consolidation, shear strength and expansion tests that were performed to provide a means to develop specific design recommendations based on the mechanical properties of the soil. CLASSIFICATION AND COMPACTION TESTS Unit Weight and Moisture Content Determinations: Each undisturbed sample was weighed and measured to determine its unit weight. A small portion of each sample was then subjected to tests to determine its moisture content. This was used to determine the dry density of the soil in its natural condition. The results of this test are shown on the Bore logs. Maximum Density -Optimum Moisture Determinations: Representative soil types were selected for maximum density determinations. This test was performed in accordance with the ASTM Standard D1557-91, Test Method A. The results of this test are presented graphically in this appendix. The maximum densities are compared to the field densities of the soil to determine the existing relative compaction to the soil. This is shown on the Sore Logs, and is useful in estimating'thc strength and compressibility of the soil. Cla-ssification Tests': Soil samples were selected for classification tests: 'The'se'tests consist of"mechinical 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 catcgor9zes the soil' into groups having similar engineering characteristics: The results of this test are very usehil for'detecting variations in the soil and for selecting samples for further tests.` SOIL MECHANIC'S TESTS Direct Shear Tests: One bulk sample was setected for Direct Shear testing. This test measures the shear strength of the soil under various normal pressures and .is used in developing parameters for foundation design and lateral design. Tests were performed using recompacted specimens that were saturated prior to tests. Tests were performed using a strain controlled apparatus with normal pressures ranging from 800 to 2300 pounds per square foot. Expansion 'tests: One bulk sample was select.ed for Expansion testing. Expansion tests were performed in accordance with the UBC Standard 18-2. This test consists of remolding 4 -inch diameter by 1 -inch thick 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. Consolidation Tests: Two relatively undisturbed samples were selected for consolidation testing. For this testi; one - inch thick test specimens are subjected to vertical loads varying from 575 psf to 11520 psi applied progress ively..The consolidation at each load increment was recorded prior to placement of each subsequent load. The specimens were saturated at the 575 psf or 720 psf load increment. Sladden Engineering 450 Egan Avenue, Beaumont CA 92223 (951) 845-7743 Fax (951) 845-8863 Maximum Density/Optimum Moisture ASTM D698/D1557 Project Number: 522-08147 June 24, 2008 Project Name: Lot 25A - Madison Club Lab TD Number: LN6-08282 ASTM D-1557 A Sample Location: BH -1 Bulk 1@ 0-5' Rammer Type: Machine Description: Gray Brown Sandy Silt Maximum Density: 116.5 pef Optimum Moisture: 13.5% Sieve Site % Retained 3" ] /4 3/8" #4 14,5 140 135 130 115 Fmm� LEM �===11 i Sg =2.65, 2-701-7 -75% 1 ME 1 ILE u R' mm =W" qh, MEN US a. 5 10 15 20 25 Moisture Content,,% Buena Park - Palm Desert - Hemet r 9 j Sladden Engineering 450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 Gradation ASTM C117 & C136 Project Number: 522-08147 June 24.2008 Project Name: Lot 25A - Madison Club Lab 1D Number: LN6-0'8282 Sample ID: BH -1 Bulk 1@ 0-5' Sieve Sieve Percent Size, in Size, mm Passing 2" 50.8 100.0 1 1./2" 38.1 100.0 1 " 25.4 100.0 3/4" 19.1 100.0 1/2" 12.7 1.00.0 3/8" -,9.53 100.0 #4 4.75 100.0 #8 2.36 100.0 til6 1.18 99.8 #30 0.60 99.4 j #50 0.30 96.4 #100 0.15 82.6 #200 0.075 59.5 uucua 1 aan - i a1i11 11"G3G11 - r1G11101 Sladden Engineering - f 450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 Gradation ASTM CI 17 & C136 Project Number: 522=08147 June 24, 2008 Project Name: Lot 25A - Madison Club Lab ID Number: LN6-08282 Sample 1D: 13H-2 #3 2 10' l Sieve Sieve Percent Size, in Size, mm Passing 1 " 25.4 100.0 3/4" 19,1 100.0 1/2" 12:7 100.0 3/8" 9.53 100.0 #4 4.75 100.0 #8 2.36 100.0 #16 1.18 99.8 #30 0.60 99.6 #50 0.30 97.2 #100 0.15 76.3 #200 0.074 45.3 100 JVI, J 70 en 60 — El HIM 50 40. I I G.. �1 -I i.. �... __..�._... .. . .. ........ �.. j \' 30 I 20 10 -- _._- 'i ' i 100.000 10.000 1.000 0.100 0.010 0.001 Sieve Siz-'Mm Buena Park • Palm Desert • Hemet Sladden Engineering 450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 Gradation ASTM 0117 & C136 Project Number: 522-08147 June 24, 2008 Project Name: Lot 25A - Madison Club Lab ID Number: LN6=08282 Sample ID: BH -3 #4 @ 15' Sieve Sieve Percent Sizc,.in Size, mrn Passing 1" 25.4 100.0 3/4" 19.1 100.0 1/2" 12.7 100.0 3/8" 9.53 100.0 #4 4.75 100.0 #8 2.36 100.0 #16 1.18 99.8 #30 0.60 99.5 450 0.30 91.1 #100 0.15 59.5 9200 0.074 16.6 Buena Park • Palm Desert - Hemet Sladden Engineering 450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax(951)845-8863 Gradation ASTM CI 17 &C136 Project Number 522-08147 Project Ndme:' Lot 25A - Madison Club Lab ID Number: LN6-08282 Sample ID: BH -4 #5 @ 20' Sieve Sieve Percent Size, in Size, mm Passing ill 25.4 100.0 3/4" _ 19.1 100.0 1/2, 12.7 100.0 3/8" 9.53 100.0 #4 4.75 100.0 #8 2:36 100.0 #16 1.18 100.0 #30 0.60 99.8 #50 0.30 98.5 #100 0.15 88.6 #200 0.074 39.4 June 24, 2008 100.000 10.000 1.000 0.100 0.010 0.001 Sieve Size, mm Buena Park - Palm Desert - Hemet r r Sladden Engineering 450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax(951)845-8863 Expansion Index ASTM D 4829(UBC 29-2 Job Number: 522-08147 Job Name: Lot 25A - Madison Club Lab TD Number: LN6=08282 Sample; ID: BH -1 Bulk 1 r@ 0-5' Soil Description: Gtay Brown Sandy Silt Wt of. Soil + Ring: 564.3 Wei ht of Rin : 188.8 Wt of Wet.Soil: 375.5 Percent Moisture; 12.0% Wet Density, c.f- 113.8 Dry Denstiy, pef:. 101.6 Saturation: 49.2 EXDansion Rook # Z Date/Time 6/20/2008 2:45 PM Initial Reading 0.0000 Final'Reading 0.0151 Expansion Index 15 (Final - Initial) x 1060 Corrected Expansion Index 15 Buena Park • :Palm Desert • Hemet June 24, 2008 I Direct Shear ASTM D 3080-90 (modified for unconsolidated, undrained conditions) Job Nuanber 522-08147 June 24, 2008 Job Name Lot 25A - Madison Club Initial Dry Density: 104.8 pcf Lab TD No. LN6-08282 Initial Mosture Content: 13.7 % Sample 1D 1W.1 Bulk 1 c@ 0-5' Peak Friction Angle (0): 32° Classification Gray. Brown Sandy Silt Cohesion (c): 180 psf Sample Type Remolded @ 90% of Maximum Density Test Results 1 2 3 4 Average Moisture Content, % 22.4 22.4 22.4. 22.4 22.4 Saturation, % _ 99.7 99.7 99.7 99.7 9.9.7 Norhial_Stress, psf 701 1,401 2,803 - . . 5,605 Peak Stress, psf 592 1,097 1,886 3,662 ti • Peak Stress .Linear (Peak Stress) 6000- 5500 _ ........ .._.—_ 5000--- 4500 000 -4500 -.._ —... -- ----- - 4000 3500 - 3000 2500 — rn 2000 _ ........ - 1500 __...--......_........ ...... - — 1000-- 500 000 50('1 _- 0 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000 5,500 6,000 Normal Stress, psf - Direct Shear Sladden Fnj ineering Revised 12)03/62 Sledden Engineering 450 Egan Avenue; Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 One Dimensional Consolidation ASTM D2435 & D5333 Job Number. 522-08147 June 24, 2008 Job Name: Lot 25A - Madison Club Lab ID Nurirnber: L146=08282 initial Dry Density, pcf. 105.5 Sample ID: BH -1.#2 @ 5' Initial Moisture, %: 16.4 Soil Description: Gray Brown Sandy Silt w/Clay Seams Initial Void Ratio: 0.581 Specific Gravity: 2.67 - Hydrocollapse: 0.1% @ 0.702 ksf % Change In Height vs Normal Presssure Diagram =0 Before Saturation —O— A$cr Saturation $- Rebound --F hydro Consolidation i=- 0.1 1.0 10.0 100.0 Normal Load (ksf Buena Park • Palm Desert • Hemet Sladden Engineering. 450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 One Dimensional Consolidation ASTM D2435 & 05333 . Job Number: 522-08147. June 24, 2008 Job Name: Lot 25A - Madison Club Lab ID Number: LN6-08282 Initial Dry Density, pef: 108.1 Sample ID: BH4 #2 @ 5' Initial Moisture, %: 15.4 Soil Description: Gray Brown Silty Sand w/Clay Seams Initial Void Ratio. 0.542 - S ecityc GCavi 2 67 p ty. Change In Aelght vs Normal Presssure Diagram —O -Before Saturation is After Saturation --8— Rcbound -a= Hydro. Consolidation 0.1 1.0 10.0 100.0 Normal Load (ksl) - Buena Park - Palm Desert 9 Hemet E . , CR Sladden Engineering 6782 Stanton Ave., Suite A, Buena Park, CA 90621 (714) 523-0952 Fax (714) 523-1369 77-725 Enfield Lane Suite 100, Palm Oeisert, CA 92211 (760) 772-3893 Fax (760) 772-3895 450 Egan Avenue, Beaumont, CA 92223 (951) 845-7743 Fax (951) 845-8863 bate: June 25, 2008 Account No.: 544-08147 Customer: Cox, Castle & Nicholson; LLP Location: Lot.25 Madison Club, L.Q Analytical Report Corrosion Series pH Soluble Sulfates Soluble Chloride Min. Resistivity per CA 643 per CA 417 per CA 422 per CA 643 ppm ppm ohm=crh Lot 25A 8.9 1,200 210 750 BH@0=5' ` 1 C Rpt 544-08147 062308 APPENDIX C Seismic'Hazards Map Seismic Analyses Output Data C'' A T TFCIT?ATF A 1P A T rr it k f AD 1100 1000 ' 9'00 800 700 600-- 560 400 300 L 20'0 100 ~�� ITE i 4 r• -100 . -400 -300 -200 -100 0 100 200 300 400 500 600 (fu % ConterMinous 48 States 2006 International Building Code Latitude = 33.6629 - LongitUde = -116.247455 Spectral Response Accelerations Ss and Si Ss and S1 = Mapped Spectral Acceleration Values Site Class B - Fa = 1.0 ,Fv =1.0 Data are based on a 0.01 deg grid spacing Period Sa 0.2 1.500 (Ss, Site Class B) 1.0 0.600 (S1, Site Class B) Conterminous 48 States 2006 International Building Code Latitude = 33.6629 Longitude = -116.247455 Spectral Response Accelerations SMs and SM1 SM.= FaSs and SM1 = FvS1 Site Class D - Fa = 1.0 ,Fv = 1.5 Period Sa Y (sec) (g) 0.2 1.500 (SM. Site Class D) 1.0 0.900 (SMI, Site Class D) Conterminous 48 States 2006 International Building Code Latitude = 33.6629 Longitude = -116.247455 SDs = 2/3 x SM and SDI =.713 x SM1 Site Class D - Fa = 1.0 ,Fv =1.5 Period Sa (sec) (g) 0:2 1.000 (SDs, Site Class D) .1 .0 0.600 (SD1, Site Class D) fo n io Conterminous 48 States 2002 Data Hazard Curve for PGS Latitude = 33.6629 Longitude = -116.247455 . Data are based on a 0.05 deg grid spacing Frequency of Exceedance values less than 1`E-4 should be used with Caution. Ground Motion Frequency of Exceedance (9) (Per year) 0.005 8.2792E-01 0.007 7.4366E-01 0.010 6.391 E-01 0.014 5.2044E-01 0.019 3.96616-01 0.027 2.8129E-01 6.038 1.8569E-01 0.053 1.1382E-01 0.074 6.6302E-02 "0.103 -3,7869E-02 0.145 2.1325E-02, 0.203 1.2434E-02 0.284 7.4508E-03 0.397 4.1678E-03 0.556 1.84866-03 0.778 5.7873E-04 1.090 1.1773E-04 1.520 1.3437E-05 2.130 5.3054E-07 Ground Motion Freq. of Exceed. Return Pd. P.E. Exp.,Time (9} (per year) (years) % (years) 0.5268 2.1053E-03 475.0 10.00 50.0 APPENDIX D Retaining Wall Seismic Load Analyses a] ._DYNAMIC LATERAL FORCE - Vertical Wall with Level Backfill ((i-0 and 0--0) PAE = (1/2)yHzKA + (3/8)yH2Kh** PA E Given: (3. Slope of Backfill H Height of Wall in Feet a Angle of Wall Friction y Unit Weight of Soil 8 Slope of Retaining Wall Kv Vertical Component of Site Acceleration O Friction Angle of Soil Kh Horizontal Component of Site Acceleration Angle of Resultant Seismic Acceleration Where: Conclusions: The lateral force PAE is assumed to act 0.6H on the wall. References: *Bowles, Joseph E., Foundation Analysis and Design, (1.9.96), Fifth Edition, Table 11-6, page 619 "Foundations and Earth Structures Design Manual 7.2, (1971), Department of th'e Navy, Naval Facilities Engineering Command, 200 Stovall Street, Alexandria Virginia 22332 Project No. 544=0$147 Sladden Enginccring Report No. 0&06-348 b* 0 .. _ _ �, H Y Kv h A ... AE . . 0.0 10, 0 ' , „ 32.. 0:32810 116 0 0.34 0.285. 3133 0.00 0 ... 0 0.559 Conclusions: The lateral force PAE is assumed to act 0.6H on the wall. References: *Bowles, Joseph E., Foundation Analysis and Design, (1.9.96), Fifth Edition, Table 11-6, page 619 "Foundations and Earth Structures Design Manual 7.2, (1971), Department of th'e Navy, Naval Facilities Engineering Command, 200 Stovall Street, Alexandria Virginia 22332 Project No. 544=0$147 Sladden Enginccring Report No. 0&06-348