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0311-229 (BLCK) Revision 1 Geotechnical ReportMR. AND MRS. JAMES BOWEN C/O DAVID OLSON ARCHITECTS 15375 BARRANCA PARKWAY, SUITE F101 IRVINE, CALIFORNIA 92618 CITY .OF LA QUINT BUILDING & SAFETY DEPT. APPROVED FOR CONSTRUCTinm DATE__ BY Ale -6 5e -11 - GEOTECHNICAL ENGINEERING REPORT PROPOSED BOWEN RESIDENCE AND GUEST HOUSE LOT 21, TRACT 27728, BANFIELD DRIVE . THE QUARRY LA QUINTA, CALIFORNIA © 2002 Earth Systems Southwest Unauthorized use or copying of this document is strictly prohibited without the express written consent of Earth Systems Southwest. File No.: 08617-01 02-05-778 1 Earth Systems Southwest IMay 20, 2002 ' Mr. and Mrs. James Bowen c/o David Olson Architects 15375 Barranca Parkway, Suite F101 Irvine, California 92618 ' Attention: Mr. David Olson Subject: Geotechnical Engineering Report ' Project: Proposed Bowen Residence and Guest House Lot 21, Banfield Drive, Tract 27728, The Quarry La Quinta, California 10134 Sixth Street, Unit G Rancho Cucamonga, CA 91730 (909)484-5455 FAX (909) 484-5995 File No.: 08617-01 02-05-778 This Geotechnical Engineering Report is prepared for the proposed Bowen Residence & Guest House to be located on Lot 21 on Banfield Drive of The Quarry, Tract 27728, in the City of La Quinta, California. This report presents our findings and recommendations for site grading and foundation design, incorporating the information supplied to our office. The site is suitable for the proposed development provided the recommendations in this report are followed in design and construction. This report should stand as a whole, and no part of the report should be excerpted or used to the exclusion of any other part. We consider the most significant geologic hazard to the project to be the potential for moderate to severe seismic shaking that is likely to occur during the design life of the proposed structures. The project site is located in the highly seismic Southern California region within the influence of several fault systems that are considered to be active or potentially active. The site is located in Seismic Zone 4 of the 1997 Uniform Building Code (UBC). Structures should be designed in accordance with the values and parameters given within the UBC. 'Near surface soils exhibited a severe to moderate corrosion potential. This report completes our scope of services in accordance with our agreement, dated March 28, 2002. Other services that 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 services are provided. Unless requested in writing, the client is responsible to distribute this report to the appropriate governing agency or other members of the design team. We appreciate the opportunity to provide our professional services. Please contact our office if there are any questions or comments concerning this report or its recommendations. Respectfully su ssi EARTH SY ST %� ` ' i U -L F Craig S. Hi � 38234 E PE03/3 OS rn Z CE 38234 * SER/csh/dac �91�OCM1.`�OP��P Distribution: F chitects, IRC File, 2/BC File � 1 Soil Conditions......................................................................................................4 ' Groundwater.........................................................................................................4 TABLE OF CONTENTS Page Geologic Setting..................:.................................................................................4 ' 3.4 Geologic Hazards..................................................................................................4 ' 1.0 INTRODUCTION 1.1 ........................................................................................................1 Project Description................................................................................................1 4.1 1.2 Site Description.....................................................................................................1 4.2 Geotechnical Constraints and Mitigation...............................................................6 1.3 Purpose and Scope of Work..................................................................................1 5.8 2.0 METHODS OF INVESTIGATION...........................................................................3 2.1 Field Exploration..................................................................................................3 ' 2.2 Laboratory Testing................................................................................................3 3.0 DISCUSSION...............................................................................................................4 ' 3.1 Soil Conditions......................................................................................................4 3.2 Groundwater.........................................................................................................4 3.3 Geologic Setting..................:.................................................................................4 ' 3.4 Geologic Hazards..................................................................................................4 4.0 CONCLUSIONS..........................................................................................................6 ' 4.1 General..................................................................................................................6 Retaining Walls...................................................................................................11 4.2 Geotechnical Constraints and Mitigation...............................................................6 5.0 RECOMMENDATIONS.............................................................................................7 5.1 Site Development - Grading.................................................................................7 5.2 Excavations and Utility Trenches.........................................................................8 5.3 Slope Stability of Graded Slopes..........................................................................8 5.4 Foundations...........................................................................................................8 5.5 Slabs-on-Grade...................................................................................................10 5.6 Retaining Walls...................................................................................................11 5.7 Mitigation of Soil Corrosivity.............................................................................1 l 5.8 Seismic Design Criteria......................................................................................12 6.0 LIMITATIONS AND ADDITIONAL SERVICES................................................13 6.1 Uniformity of Conditions and Limitations.........................................................13 6.2 Additional Services.............................................................................................14 REFERENCES...........................................................................................................15 APPENDIX A Site Location -Map Boring Location Map Table 1 — Fault Parameters Logs of Borings APPENDIX B Laboratory Test Results EARTH SYSTEMS SOUTHWEST i 1 May 20, 2002 - 1 - File No.: 08617-01 ' 02-05-778 1.0 INTRODUCTION ' 1.1 Project Description ' This Geotechnical Engineering Report has been prepared for the proposed residential structure and guesthouse to be located on Lot 21, Banfield Drive of The Quarry, Tract 27728, in the City of La Quinta, California. We understand that the proposed 4,500 square foot residential structure ' will be a wood -frame construction with a tile roof and will be supported by conventional shallow continuous or pad footings. A 1,200 square foot garage and a 600 square foot guesthouse with hardscape walkways and landscaping are also planned. Based on existing site topography, site ' grading is expected to be minimal. We have used maximum column loads of 20 kips and a maximum wall loading of 1.5 kips per ' linear foot as a basis for the foundation recommendations. Loading is assumed to be dead plus actual live load. The preliminary design loading was assumed based on similar type construction, 'if actual structural loading exceeds these assumed values, we would need to reevaluate the given recommendations. 1.2 Site Description ' The proposed residence is to be constructed on a vacant, approximately rectangular shaped lot located on Lot 21 of Tract 27728 within The Quarry in the City of La Quinta, California. The ' site is bordered on the south by an existing residence and on the east by a golf course. The site location is shown on Figure 1 in Appendix A. The subject lot is currently vacant, flat and essentially level. 1.3 Purpose and Scope of Work ' The purpose for our services was to evaluate the site soil conditions and to provide professional opinions and recommendations regarding the proposed development of the site. The scope of work included the following: ➢ A general reconnaissance of the site. ➢ Subsurface exploration by drilling four exploratory borings to depths ranging from 14.5 to 21.5 feet. ' ➢ Laboratory testing of selected soil samples obtained from the exploratory borings. ➢ Review of selected published technical literature pertaining to the site. ➢ Engineering analysis and evaluation of the acquired data from the exploration and testing ' programs. ➢ A summary of our findings and recommendations in this written report. This report contains the following: ➢ Discussions on subsurface soil and groundwater conditions. ➢ Discussions on regional and local geologic conditions. ' ➢ Discussions on geologic and seismic hazards. ➢ Graphic and tabulated results of laboratory tests and field studies. ➢ Recommendations regarding: ' • Site development and grading criteria. • Excavation conditions and buried utility installations. • Structure foundation type and design. ' EARTH SYSTEMS SOUTHWEST May 20, 2002 - 2 - File No.: 08617-01 02-05-778 • Allowable foundation bearing capacity and expected total and differential settlements. • Concrete slabs -on -grade. • Lateral earth pressures and coefficients. • Mitigation of the potential. corrosivity of site soils to concrete and steel reinforcement. • Seismic design parameters. Not Contained In This Report: Although available through Earth Systems Southwest, the current scope of our services does not include: ➢ A corrosive study to determine cathodic protection of concrete or buried pipes. ➢ An environmental assessment. ➢ Investigation for the presence or absence of wetlands, hazardous or toxic materials in the soil, surface water, groundwater, or air on, below, or adjacent to the subject property. EARTH SYSTEMS SOUTHWEST May 20, 2002 - 3 - File No.: 08617-01 i02-05-778 2.0 METHODS OF INVESTIGATION 2.1 Field Exploration Four exploratory borings were drilled to depths ranging from 14.5 to 21.5 feet below the existing ground surface to observe the soil profile and to obtain samples for laboratory testing. The borings were drilled on April 5, 2002, using 8 -inch outside diameter hollow -stem augers, and powered by a CME 45 truck -mounted drilling rig. The boring locations are shown on the boring location map, Figure 2, in Appendix A. The locations shown are approximate, established by pacing and sighting from existing topographic features. Samples were obtained within the test borings using a Standard Penetration (SPT) sampler (ASTM D 1586) and a Modified California (MC) ring sampler (ASTM D 3550 with shoe similar to ASTM D 1586). The SPT sampler has a 2 -inch outside diameter and a 1.38 -inch inside diameter. The MC sampler has a 3 -inch outside diameter and a 2.37 -inch -inside diameter. The samples were obtained by driving the sampler with a 140 -pound automatic hammer dropping 30 inches in general accordance with ASTM D 1586. Recovered soil samples were sealed in containers and returned to the laboratory. Bulk samples were also obtained from auger cuttings, representing a mixture of soils encountered at the depths noted. The final logs of the borings represent our interpretation of the contents of the field logs and the results of laboratory testing performed on the samples obtained during the subsurface investigation. The final logs are included in Appendix A of this report. The stratification lines represent the approximate boundaries between soil types although the transitions, however, may be gradational. 2.2 Laboratory Testing Samples were reviewed along with field logs to select those that would be analyzed further. Those selected for laboratory testing include soils that would be exposed and used during grading, and those deemed to be within the influence of the proposed structure. Test results are presented in graphic and tabular form in Appendix B of this report. The tests were conducted in general accordance with the procedures of the American Society for Testing and Materials (ASTM) or other standardized methods as referenced below. Our testing program consisted of the following: In-situ Moisture Content and Unit Dry Weight for the ring samples (ASTM D 2937). Maximum density tests were performed to evaluate the moisture -density relationship of typical soils encountered (ASTM D 1557-91). Particle Size Analysis (ASTM D 422) to classify and evaluate soil composition. The gradation characteristics of selected samples were made by hydrometer and sieve analysis procedures. Chemical Analyses (Soluble Sulfates & Chlorides, pH, and Electrical Resistivity) to evaluate the potential adverse effects of the soil on concrete and steel. EARTH SYSTEMS SOUTHWEST May 20, 2002 - 4 - File No.: 08617-01 ' 02-05-778 3.0 DISCUSSION ' 3.1 Soil Conditions The field exploration indicates that site soils consist primarily of loose Silty Sands (SM) and Sands (SP -SM) with occasional gravel and cobbles. The soils encountered are generally medium dense to dense and slightly moist to dry. The boring logs provided in Appendix A include more detailed descriptions of the soils encountered. The soils are visually classified to be in the very ' low expansion category in accordance with Table 18A -I -B of the Uniform Building Code. 3.2 Groundwater Groundwater was not encountered in the exploratory borings drilled to a maximum depth of 21.5 feet. Information obtained from the Coachella Valley Water District indicates that the average ' depth to groundwater in a well located approximately 1/2 mile to the east of the site was approximately 165 feet below the ground surface in the year 2001. ' Because groundwater levels may fluctuate with precipitation, irrigation, drainage, regional pumping from wells, and site grading, there is some uncertainty in the accuracy of short-term ' water level measurements. Therefore, the groundwater level described above may not represent an accurate or permanent condition. Nevertheless, based on currently available information, groundwater is not expected to be a factor in design or construction at this site. ' 3.3 Geologic Setting ' 3.3.1 Regional Geology: The site lies within the Coachella Valley, a part of the Colorado Desert geomorphic province. A significant feature within the Colorado Desert geomorphic province is the Salton Trough. The Salton Trough is a large northwest -trending structural depression that ' extends from San Gorgonio Pass, approximately 180 miles to the Gulf of California. Much of this depression in the area of the Salton Sea is below sea level. ' The Coachella Valley forms the northerly portion of the Salton Trough. The Coachella Valley contains a thick sequence of sedimentary deposits that are Miocene to recent in age. Mountains surrounding the Coachella Valley include the Little San Bernardino Mountains on the northeast, ' foothills of the San Bernardino Mountains on the northwest, and the San Jacinto and Santa Rosa Mountains on the southwest. These mountains expose primarily Precambrian metamorphic and Mesozoic granitic rocks. The San Andreas Fault zone within the Coachella Valley consists of ' the Garnet Hill Fault, the Banning Fault, and the Mission Creek Fault that traverse along the northeast. margin of the valley. ' 3.3.2 Local Geolo : The project site is located on lacustrine (lake bed) and alluvial (stream deposited) deposits at the base of the Santa Rosa Mountains. ' 3.4 Geologic Hazards Geologic hazards that may affect the region include seismic hazards (ground shaking, surface ' fault rupture, soil liquefaction, and other secondary earthquake -related hazards). ' EARTH SYSTEMS SOUTHWEST May 20, 2002 - 5 - File No.: 08617-01 02-05-778 3.4.1 Seismic Sources: Several active faults or seismic zones lie within 62 miles ' (100 kilometers) of the project site as shown on Table 1 in Appendix A. The primary seismic hazard to the site is strong groundshaking from earthquakes along the San Andreas and San Jacinto Faults. The 1997 Uniform Building Code seismic design parameters are presented in ' Section 5.8 of this report. 3.4.2 Surface Fault Rupture: The project site does not lie within a currently delineated State of ' California, Alquist-Priolo Earthquake Fault Zone (Hart, 1994). Therefore, active fault rupture is believed to be unlikely to occur at the project site based on currently available information. While fault rupture would most likely occur along previously established fault traces, future fault ' rupture could occur at other locations. 3.4.3 Soil Liquefaction: Liquefaction is the loss of soil strength from sudden shock (usually ' earthquake shaking), causing the soil to become a fluid mass. In general, for the effects of liquefaction to be manifested at the surface, groundwater levels must be within 50 feet of the ground surface and the soils within the saturated zone must also be susceptible to liquefaction. ' The potential for liquefaction to occur at this site is considered negligible because the depth of groundwater beneath the site exceeds 50 feet. No free groundwater was encountered in our exploratory borings. In addition, the project does not lie within the Riverside County ' liquefaction study zone. 0 ' EARTH SYSTEMS SOUTHWEST May 20 2002 - 6 - File No.: 08617-01 ' 02-05-778 4.0 CONCLUSIONS ' The following is a summary of our conclusions and professional opinions based on the data obtained from a review of selected technical literature and the site evaluation. 4.1 General ➢ From a geotechnical perspective, the site is suitable for the proposed development ' provided. The recommendations in this report should be incorporated into the design and construction of this project. ' 4.2 Geotechnical Constraints and Mitigation ➢ The primary geologic hazard is severe ground shaking from earthquakes originating on ' nearby faults. A major earthquake above magnitude 7 originating on the local segment of the San Andreas Fault zone would be the critical seismic event that may affect the site within the design life of the proposed development. Engineered design, earthquake - resistant construction, and rock fall protection should increase safety and allow development of seismic areas. ' ➢ The project site is. in seismic Zone 4 and about 15.6 km from a Type A seismic source as defined in the Uniform Building Code. A qualified professional should design any permanent structure constructed on the site. The minimum seismic design should ' comply with the latest edition of the Uniform Building Code. ➢ The soils are susceptible to wind and water erosion. Preventative measures to reduce ' seasonal flooding and erosion should be incorporated into site grading plans. Dust control should also be implemented during construction. ' ➢ Other geologic hazards including ground rupture, liquefaction, seismically induced flooding, and landslides are considered low or negligible on this site. ' ➢ Soils can be readily cut by normal grading equipment. ➢ The native soils exhibited a severe to moderate potential for metal loss from ' electrochemical corrosion processes. 1 I EARTH SYSTEMS SOUTHWEST May 20, 2002 - 7 - File No.: 08617-01 ' 02-05-778 5.0 RECOMMENDATIONS ' 5.1 Site Development - Grading ' A representative of Earth Systems Southwest (ESSW) should observe site clearing, grading, and the bottom of excavations prior to placing fill. Local variations in soil conditions may warrant increasing the depth of recompaction and over -excavation. ' 5.1.1 Clearing and Grubbing: Prior to site grading, existing vegetation and other deleterious material should be removed from the proposed building, structural, and pavement areas. The ' surface should be stripped of organic growth and removed from the construction area. Areas disturbed during clearing should be properly backfilled and compacted as described below. 5.1.2 Building Pad Preparation: Because of the relatively dense nature of the majority of the ' upper soils beneath the recent fill, we recommend thorough moisture conditioning of soils in the building area. Moisture penetration to near optimum moisture should extend at least 36 inches below existing pad grade an be verified by testing. The recent fill. should either be removed or compacted as described below. The upper 2 feet below existing pad grade or 1 foot below bottom of footings, whichever is lower, should be tested afterwards to verify compaction to at least 90% relative compaction. The bottom of the sub -excavation should be scarified; moisture conditioned and recom acted to P ' at least 90 % relative compaction (ASTM D 1557) for an additional depth of 12 inches. The soils in Boring 1 are wet and will need to be dried. 5.1.3 Auxiliary Structures Subgrade Preparation: Auxiliary structures such as garden walls ' should have the foundation subgrade prepared similar to the building pad recommendations given above. The depths and lateral extent of the over -excavation may be limited to 3 feet and 2 ' feet, respectively. 5.1.4 Subgrade Preparation: In areas to receive fill, pavements, or hardscape, the subgrade ' should be scarified; moisture conditioned, and compacted to at least 90% relative compaction (ASTM D 1557) for a depth of 12 inches below finished subgrades. Compaction should be verified by testing. ' 5.1.5 Engineered Fill Soils: The native soil is suitable for use as engineered fill and utility trench backfill provided it is free of significant organic or deleterious matter. The native soil should be placed in maximum 8 -inch lifts (loose) and compacted to at least 90% relative compaction (ASTM D 1557) near its optimum moisture content. Compaction should be verified by testing. Rocks larger than 6 inches in greatest dimension should be removed from fill or ' backfill material. Imported fill soils if required) should be non -expansive, granular soils meeting the ' USCS classifications of SM, SP -SM, or SW -SM with a maximum rock size of 3 inches and 5 to 35% passing the No. 200 sieve. The geotechnical engineer should evaluate the import fill soils before hauling to the site. However, because of the potential variations within the borrow ' source, import soil will not be prequalified by ESSW. The imported fill should be placed in lifts no greater than 8 inches in loose thickness and compacted to at least 90% relative compaction (ASTM D 1557) near optimum moisture content. ' EARTH SYSTEMS SOUTHWEST May 20, 2002 - 8 - File No.: 08617-01 ' 02-05-778 5.1.6 Shrinkage: The shrinkage factor for earthwork is expected to be less than 10 percent for ' the upper excavated or scarified site soils. This estimate is based on compactive effort to achieve an average relative compaction of about 92% and may vary with contractor methods. Subsidence is estimated to be less than 1 foot. Losses from site clearing and removal of existing site improvements may affect earthwork quantity calculations and should be considered. 5.1.7 Site Drainage: Positive drainage should be maintained away from the structures (5% for 1 5 feet minimum) to prevent ponding and subsequent saturation of the foundation soils. Gutters and downspouts should be considered as a means to convey water away from foundations if adequate drainage is not provided. Drainage should be maintained for paved areas. Water ' should not pond on or near paved areas. 5.2 Excavations and Utility Trenches 5.2.1 General: Excavations should be made in accordance with CalOSHA requirements. Our site exploration and knowledge of the general area indicates there is a potential for caving of site excavations (utilities, footings, etc.). Excavations within sandy soil should be kept moist, but not saturated, to reduce the potential of caving or sloughing. Where excavations over 4 feet deep are planned, lateral bracing or appropriate cut slopes of 1.5:1 (horizontal: vertical) should be ' provided. No surcharge loads from stockpiled soils or construction materials should be allowed within a horizontal distance measured from the top of the excavation slope, equal to the depth of the excavation. 5.2.2 Utility Trenches: Backfill of utilities within road or public right-of-ways should be placed in conformance with the requirements of the governing agency (water district, public works ' department, etc.) Utility trench backfill within private property should be placed in conformance with the provisions of this report. In general, service lines extending inside of property may be backfilled with native soils compacted to a minimum of 90% relative compaction. Backfill Ioperations should be observed and tested to monitor compliance with these recommendations. 5.3 Slope Stability of Graded Slopes We understand that no slopes are anticipated, in case, unprotected, permanent graded slopes should not be steeper than 3:1 (horizontal: vertical) to reduce wind and rain erosion. Protected slopes with ground cover may be as steep as 2:1. However, maintenance with motorized equipment may not be possible at this inclination. Fill slopes should be overfilled and trimmed back to competent material. Slope stability calculations are not presented because no slopes are anticipated. 5.4 Foundations ' 5.4.1 General: In our professional opinion, the structure foundation can be supported on shallow foundations bearing on a zone of properly prepared and compacted soils placed as recommended ' in Section 5.1 of this report. The recommendations that follow are based on verylow expansion category soils. EARTH SYSTEMS SOUTHWEST I. ' May 20 2002 M File No.: 08617-01 02-05-778 5.4.2 Allowable Bearing Pressures: Footing design of widths, depths, and reinforcing are the responsibility of the Structural Engineer, considering the structural loading and the geotechnical parameters given in this report. A minimum footing depth of 12 inches b� w lowest adjacent grade should be maintained. A representative of ESSW should observe foundation excavations prior to placement of reinforcing steel or concrete. Any loose soil or construction debris should be removed from footing excavations prior to placement of concrete. ' 5.4.3 Conventional Spread Foundations: Allowable soil bearing pressures are given below for foundations bearing on recompacted soils as described in Section 5.1. Allowable bearing pressures are net (weight of footing and soil surcharge may be neglected). ' ➢ Continuous wall_fo-undations;=1-2--inch mini mum width and 12 inches below grade: ,2000 psf_for deadaplus design live loads Allowable increases of 150 psf per each foot of additional footing width and 150 psf for each ' additional 0.5 foot of footing depth may be used up to a maximum value',of3000 sp f. ' ➢ Isolated padfoundations,T2x t mum m 2'fooinimplan and�8 inches below grade: 2500_psf for dead_plus esign live loads Allowable increases of 250 psf per each foot of additional footing width and 250 psf-for each additional 0.5 foot of footing depth may be used up to a maximum value of 4000-psf.--/ ' A one-third (1/3) increase in the bearing pressure may be used when calculating resistance to wind or seismic loads. The allowable bearing values indicated are based on the anticipated maximum loads stated in Section 1.1 of this report. If the anticipated loads exceed these values, ' the geotechnical engineer must reevaluate the allowable bearing values and the grading requirements. Minimum reinforcement for continuous wall footings should be two—,No-4 steel reinforcing bars, one placed near the top and o en placed near the bottom inof the footing. This reinforcing is not tended to supersede -any -structural requirements provided by the structural engineer. ' 5.4.4 Expected Settlement: Estimated total static settlement, based on footings founded on firm soils as recommended, should be less than 1 inch.—Differential settlement between exterior and interior bearing members should be lessthan 1/2 -inch. -i ' 5.4.5 Frictional and Lateral Coefficients: Lateral loads may be resisted b soil friction on the Y Y base of foundations and by passive_resistance-of the soils acting on foundation walls. An allowable coefficient of friction �of 0.35 -of dead load may be used. An allowable passive equivalent fluid pressure of 300 pcf may also be used. These values include a factor of safety of 1.5. Passive resistance and frictional resistance may be used in combination if the friction ' coefficient is reduced to 0.23 of dead load forces. A one-third (1/3) increase in the passive pressure may be used when calculating resistance to wind or seismic loads. Lateral passive resistance is based on the assumption that any required backfill adjacent to foundations is properly compacted. EARTH SYSTEMS SOUTHWEST May 20, 2002 _10- File No.: 08617-01 02-05-778 5.5 Slabs -on -Grade 5.5.1 Subgrade: Concrete slabs -on -grade and flatwork should be supported by compacted soil placed in accordance with Section 5.1 of this report. 5.5.2 Vapor Barrier: In areas of moisture sensitive floor coverings, an appropriate vapor barrier should be installed to reduce moisture transmission-fromAlie_subgrade soil to the slab. For these areas an impermeable membrane; k10 -mil moisture-barrier)_should underlie the floor slabs. The membrane should be covered with 2 inches of sand to help protect it during construction and to aide in concrete curing. The sand should be lightly moistened just prior to placing the concrete. Low -slump concrete should be used to help reduce the potential for concrete shrinkage. The effectiveness of the moisture barrier is dependent upon its quality, method of overlapping, its protection during construction, and the successful sealing of the barrier around utility lines. 5.5.3 Slab thickness and reinforcement: Slab thickness and reinforcement of slab -on -grade are contingent on the recommendations of the structural engineer or architect and the expansion index of the supporting soil. Based upon our findings, a modulus of subgrade reaction of approximately 200 pounds per cubic inch can be used in concrete slab design for the expected very low expansion subgrade. Concrete slabs and flatwork should be a minimum of 4 inches thick(actual, not nominal). We suggest that the concrete slabs be reinforced witha minimum of No. 3 rebars aat=1'8=inch centers, both horizontal directions, placed at slab mid -height to resist swell`"`fofces—andr cracking. Concrete floor slabs may either be monolithically placed with the foundations or doweled after footing placement. The thickness and reinforcing given are not intended to supersede any structural requirements provided by the structural engineer. The project architect or geotechnical engineer should continually observe all reinforcing steel in slabs during placement of concrete to check for proper location within the slab. 5.5.4 Control Joints: Control joints should be provided in all concrete slabs -on -grade at a maximum spacing of 36 times the slab thickness (12 feet maximum on -center, each way) as recommended by American Concrete Institute (ACI) guidelines. All joints should form approximately square patterns to reduce the potential for randomly oriented, contraction cracks. Contraction joints in the slabs should be tooled at the time of the pour or saw cut (1/4 of slab depth) within 8 hours of concrete placement. Construction (cold) joints should consist of thickened butt joints with one-half inch dowels at 18 -inches on center or a thickened keyed joint to resist vertical deflection at the joint. All construction joints in exterior flatwork should be sealed to reduce the potential of moisture or foreign material intrusion. These procedures will reduce the potential for randomly oriented cracks, but may not prevent them from occurring. 5.5.5 Curing and Quality Control: The contractor should take precautions to reduce the potential of curling of slabs in this and desert region using proper batching, placement, and curing methods. Curing is highly effected by temperature, wind, and humidity. Quality control procedures may be used including trial batch mix designs, batch plant inspection, and on-site special inspection and testing. Typically, for this type of construction and using 2500 -psi concrete, many of these quality control procedures are not required. EARTH SYSTEMS SOUTHWEST May 20, 2002 - 11 - File No.: 08617-01 02-05-778 5.6 Retaining Walls 5.6.1 Earth Pressures: The following table presents lateral earth pressures for use in retaining wall design. The values are given as equivalent fluid pressures without surcharge loads or hydrostatic pressure. Lateral Pressures and Sliding Resistance Granular Backfill Passive Pressure 300 pcf -level ground Active Pressure (cantilever walls) 35�pcf-`level ground Use when wall is perinitted to rotate 0.1% of wall height At -Rest Pressure (restrained walls) F _-5 5pcf - level:grourid? Dynamic Lateral Earth Pressure Acting at mid height of structure, 25H psf Where H is height of backfill in feet Base Lateral Sliding Resistance Dead load x Coefficient of Friction: 0.50 Notes: 1. These values are ultimate values. A factor of safety of 1.5 should be used in stability analysis except for dynamic earth pressure where a factor of safety of 1.2 is acceptable. ' 2. Dynamic pressures are based on the Mononobe-Okabe 1929 method, additive to active earth pressure. Walls retaining less than 6 feet of soil need not consider this increased pressure. ' Upward sloping backfill or surcharge loads from nearby footings can create larger lateral pressures. Should any walls be considered for retaining sloped backfill or placed next to foundations, our office should be contacted for recommended design parameters. Surcharge ' loads should be considered if they exist within a zone between the face of the wall and a plane projected 45 degrees upward from the base of the wall. The increase in lateral earth pressure ' should be taken as 35% of the surcharge load within this zone. Retaining walls subjected to traffic loads should include a uniform surcharge load equivalent to at least 2 feet of native soil. ' 5.6.2 Drainage: A back drain or an equivalent system of backfill drainage should be incorporated into the retaining wall design. Our firm can provide construction details when the specific application is determined. Backfill immediately behind the retaining structure should be ' a free -draining granular material. In this case the native soils are considered relatively free draining. Waterproofing should be according to the designer's specifications. Water should not be allowed to pond near the top of the wall. To accomplish this, the final backfill grade should ' be such that all water is diverted away from the retaining wall. 5.6.2 Backfill and Subgrade Compaction: Compaction on the retained side of the wall within a ' horizontal distance equal to one wall height should be performed by hand -operated or other lightweight compaction equipment. This is intended to reduce potential locked -in lateral pressures caused by compaction with heavy grading equipment. Foundation subgrade ' preparation should be as specified in Section 5.1 of this report. 5.7 Mitigation of Soil Corrosivity 5.7.1 Chemical Tests: Selected chemical analyses for corrosivity were conducted on a sample of soil from the project site. The native soils were found to have a low sulfate ion (l l ppm) EARTH SYSTEMS SOUTHWEST May 20, 2002 -12- File No.: 08617-01 02-05-778 concentration an'd�_chloride_ion_(8.8_ppm) concentration. Sulfate ions can attack the cementitious material in concrete, causing weakening of the cement matrix and eventual deterioration by raveling. Chloride ions can cause corrosion of reinforcing steel. The Uniform Building Code does not require special provisions for concrete for these concentrations as tested. A minimum concrete cover of three (3) inches should be provided around steel reinforcing or embedded components exposed to native soil or landscape water (to 18 inches above grade). Additionally, the concrete should be thoroughly vibrated during placement. 5.7.2 Electrical Resistivity Tests: Electrical resistivity testing (1525 ohm -cm) of the soil suggests that the site soils may present a severe to moderate potential for metal loss from electrochemical corrosion processes. Corrosion protection of steel can be achieved by using epoxy corrosion inhibitors, asphalt coatings, cathodic protection, or encapsulating with densely consolidated concrete. A qualified corrosion engineer should be consulted regarding mitigation of the corrosive effects of site soils on metals. Earth Systems does not practice corrosion engineering and we recommend that a qualified corrosion engineer be consulted regarding mitigation of the corrosive effects of site soils on metals. The chemical test results are included in Appendix B. 5.8 Seismic Design Criteria ' This site is subject to strong ground shaking due to potential fault movements along the San Andreas and San Jacinto Faults. Engineered design and earthquake -resistant construction increase safety and allow development of seismic areas. The minimum seismic design should ' comply with the latest edition of the Uniform Building Code for Seismic Zone 4 using the seismic coefficients given in the table below. ' 1997 UBC Seismic Coefficients for Chapter 16 Seismic Provisions Reference ' Seismic Zone: 4 Figure 16-2 Seismic Zone Factor, Z: 0.4 Table 16-I Soil Profile Type: SD Table 16-J Seismic Source Type: r-:�A`� Table 16-U ' Closest Distance to Known Seismic Source: 15 -:6 -km = 7.6 miles (San Andreas Fault) Near Source Factor, Na: 1.00 Table 16-S Near Source Factor, Nv: 1700 Table 16-T ' Seismic Coefficient, Ca: 0.44 = 0.44Na Table 16-Q Seismic Coefficient, Cv: 0.64 = 0.64Nv Table 16-R ' The intent of the UBC lateral force requirements is to provide a structural design that will resist collapse to provide reasonable life safety from a major earthquake, but may experience some ' structural and nonstructural damage. A fundamental tenet of seismic design is that inelastic yielding is allowed to adapt to the seismic demand on the structure. In other words, damage is allowed. The UBC lateral force requirements should be considered a minimum design. 1 ' EARTH SYSTEMS SOUTHWEST May 20, 2002 - 13 - File No.: 08617-01 02-05-778 6.0 LIMITATIONS AND ADDITIONAL SERVICES 6.1 Uniformity of Conditions and Limitations ' Our findings and recommendations in this report are based on selected points of field exploration, laboratory testing, and our understanding of the proposed project. Furthermore, our findings and recommendations are based on the assumption that soil conditions do not vary ' significantly from those found at specific exploratory locations. Variations in soil or groundwater conditions could exist between and beyond the exploration points. The nature and extent of these variations may not become evident until construction. Variations in soil or ' groundwater may require additional studies, consultation, and possible revisions to our recommendations. ' Findings of this report are valid as of the issued date of the report. However, changes in conditions of a property can occur with passage of time whether they are from natural processes or works of man on this or adjoining properties. In addition, changes in applicable 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 be relied upon after a period of one year. ' In the event that any changes in the nature, design, or location of structures 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 are modified or verified in writing. This report is issued with the understanding that the owner, or the owner's representative, has the ' responsibility to bring the information and recommendations contained herein to the attention of the architect and engineers for the project so that they are incorporated into the plans and specifications for the project. The owner, or the owner's representative, also has the ' responsibility to take the necessary steps to see that the general contractor and all subcontractors follow such recommendations. It is further understood that the owner or the owner's representative is responsible for submittal of this report to the appropriate governing agencies. ' As the Geotechnical Engineer of Record for this project, Earth Systems Southwest (ESSW) has striven to provide our services in accordance with generally accepted geotechnical engineering ' practices in this locality at this time. No warranty or guarantee is express or implied. This report was prepared for the exclusive use of the Client and the Client's authorized agents. ' ESSW should be provided the opportunity for a general review of final design and specifications in order that earthwork and foundation recommendations may be properly interpreted and implemented in the design and specifications. If ESSW is not accorded the privilege of making ' this recommended review, we can assume no responsibility for misinterpretation of our recommendations. Although available through ESSW, the current scope of our services does not include an environmental assessment, or investigation for the presence or absence of wetlands, hazardous or toxic materials in the soil, surface water, groundwater or air on, below, or adjacent to the subject ' property. ' EARTH SYSTEMS SOUTHWEST 'May 20, 2002 -14- File No.: 08617-01 02-05-778 6.2 Additional Services This report is based on the assumption that an adequate program of client consultation, construction monitoring, and testing will be performed during the final design and construction phases to check compliance with these recommendations. Maintaining ESSW as the geotechnical consultant from beginning to end of the project will provide continuity of services. The geotechnical engineering firm providing tests and observations shall assume the responsibility of Geotechnical Engineer of Record. Construction monitoring and testing would be additional services provided by our firm. The costs of these services are not included in our present fee arrangements, but can be obtained from our office. The recommended review, tests, and observations include, but are not necessarily limited to the following: • Consultation during the final design stages of the project. • Review of the building and grading plans to observe that recommendations of our report have been properly implemented into the design. • Observation and testing during site preparation, grading and placement of engineered fill as required by UBC Sections 1701 and 3317 or local grading ordinances. • Consultation as required during construction. Appendices as cited are attached and complete this report. EARTH SYSTEMS SOUTHWEST May 20 2002 -15 - File No.: 08617-01 02-05-778 REFERENCES Abrahamson, N., and Shedlock, K., editors, 1997, Ground motion attenuation relationships: Seismological Research Letters, v. 68, no. 1, January 1997 special issue, 256 p. ' American Concrete Institute (ACI), 1996, ACI Manual of Concrete Practice, Parts 1 through 5. American Society of Civil Engineers (ASCE), 2000, ASCE Standard 7-98, Minimum Design Loads for Buildings and Other Structures. Blake, B.F., 2000, FRISKSP v. 4.00, A Computer Program for the Probabilistic Estimation of Peak ' Acceleration and Uniform Hazard Spectra Using 3-D Faults as Earthquake Sources, Users Manual. ' Boore, D.M., Joyner, W.B., and Fumal, T.E., 1993, Estimation of Response Spectra and Peak Accelerations from Western North American Earthquakes: An Interim Report; U.S. Geological Survey Open -File Report 93-509,15 p. ' Boore, D.M., Joyner, W.B., and Fumal, T.E., 1994, Estimation of Response Spectra and Peak Acceleration from Western North American Earthquakes: An Interim Report, Part 2, ' U.S. Geological Survey Open -File Report 94-127. California Department of Conservation, Division of Mines and Geology (CDMG), 1997, Guidelines ' for Evaluating and Mitigating Seismic Hazards in California, Special Publication 117. California Department of Water Resources, 1964, Coachella Valley Investigation, Bulletin No. 108, 146 pp. Department of Defense, 1997, Soil Dynamics and Special Design Aspects, MIL-HDBK-1007/3, ' superseding NAVFAC DM 7.3. Department of the Navy, Naval Facilities Engineering Command (NAVFAC), 1986, Foundations ' and Earth Structures, NAVFAC DM 7.02. Envicom Corporation and the County of Riverside Planning Department, 1976, Seismic Safety and ' Safety General Plan Elements Technical Report, County of Riverside. Ellsworth, W.L., 1990, "Earthquake History, 1769-1989" in: The San Andreas Fault System, ' California: U.S. Geological Survey Professional Paper 1515, 283 p. Federal Emergency Management Agency (FEMA), 1997, NEHRP Recommended Provisions for Seismic Regulations for New Buildings and Other Structures, Part 1 — Provisions and Part 2 - Commentary. I Hart, E.W., 1994, Fault -Rupture Hazard Zones in California: California Division of Mines and Geology Special Publication 42, 34 p. International Conference of Building Officials, 1997, Uniform Building Code, 1997 Edition. International Conference of Building Officials, 2000, International Building Code, 2000 Edition. ' EARTH SYSTEMS SOUTHWEST May 20, 2002 -16- File No.: 08617-01 02-05-778 Jennings, C.W, 1994, Fault Activity Map of California and Adjacent Areas: California Division of Mines and Geology, Geological Data Map No. 6, scale 1:750,000. Petersen, M.D., Bryant, W.A., Cramer, C.H., Cao, T., Reichle, M.S., Frankel, A.D., Leinkaemper, J.J., McCrory, P.A., and Schwarz, D.P., 1996, Probabilistic Seismic Hazard Assessment for the State of California: California Division of Mines and Geology Open -File Report 96-08. Prakash, S., 1982, Soil Dynamics, McGraw-Hill Book Company Proctor, R. J., 1968, Geology of the Desert Hot Springs - Upper Coachella Valley Area, California Division of Mines and Geology, DMG Special Report 94. Reichard, E.G. and Mead, J.K., 1991, Evaluation of a Groundwater Flow and Transport Model of the Upper Coachella Valley, California, U.S.G.S. Open -File Report 91-4142. Riverside County Planning Department, 1984, Seismic Safety Element of the Riverside County General Plan, Amended. Rogers, T.H., 1966, Geologic Map of California - Santa Ana Sheet, California Division of Mines and Geology Regional Map Series, scale 1:250,000. Sieh, K., Stuiver, M., and Brillinger, D., 1989, A More Precise Chronology of Earthquakes Produced by the San Andreas Fault in Southern California: Journal of Geophysical Research, Vol. 94, No. Bl, January 10, 1989, pp. 603-623. Structural Engineers Association of California (SEAOC), 1996, Recommended Lateral Force Requirements and Commentary. Tokimatsu, K, and Seed, H.B., 1987, Evaluation of Settlements in Sands Due To Earthquake Shaking, ASCE, Journal of Geotechnical Engineering, Vol. 113, No. 8, August 1987. Van de Kamp, P.C., 1973, Holocene Continental Sedimentation in the Salton Basin, California: A Reconnaissance, Geological Society of America, Vol. 84, March 1973. Working Group on California Earthquake Probabilities, 1995, Seismic Hazards in Southern ' California: Probable Earthquakes, 1994-2024: Bulletin of the Seismological Society of America, Vol. 85, No. 2, pp. 379-439. I Wallace, R. E., 1990, The San Andreas Fault System, California: U.S. Geological Survey Professional Paper 1515, 283 p. 1 EARTH SYSTEMS SOUTHWEST APPENDIX A Site Location Map Boring Location Map Table 1 — Fault Parameters Logs of Borings EARTH SYSTEMS SOUTHWEST �/• ��/ � �� `��� I ��1 /• ��,l��i��\,c'�"`lig_" _ p ii ,II _------- •� .:, .•o -12 E AV N E 5 ni Lap W �; x � z R p, 1 n ,.,� ` is l:, _•_5..'e: �F_r.-_— ........... AVENUE s n .".' 11 58 00 g ` 2 avec - 28 n Pit f7. Lake'Cahuil :ti't SIT �__ i e J fes.' ` , •.i _ "til.! : ��— 4a.:,,�».u..>,;•�� u ice: - 'i- _i; _ r r' ( � � , fir- ' �'�• '�,� c�l,t COunt'Y. Par .:n " iF;' , >� 1 ---,,i •`—^\y1 �'�� \ ��� _�f\ it ''f: !� `� � �^'\`,�\ t—_OU 7 I,--..,: Y.9,z,•e=�• 20 IK- _ Y { � � = - i, .. � Jr ..: t { �\ �:'/- _\_ \ i:;,-// •.\ �\- O i J�.�;s ;" .,J/� 0 1 ti r. +/ . � � "; �' f.IF \:,% • J \'-...� "1i `r:•:.-t.`:t :.1r•-- _ \"' ,i ��--r--Jrri �'�I ..:'1 �- /(':" `�; ii � ({i(•_.7�1f�:�; \, �!_ __ ---: _____ _="'�1>_, '". —_.> \. :' %91 I, �/1/,•. -\ l ,:, `i i:' �Y�� _ t:1: C<:., .1 isx.n• nba xny � � t �:r .. ice. '?::' J %--,�_.. ii C'�{;` >+•_ %; �.� �_\400 \ ! •\ `i!ily'-. ... o� ' <:r.,`-''�=azs'W;v- .\r•': .j''r .� i�_� �.. i'' '�' v 7,. �_ a:>e.. o (/ _s'i"�\�` :q ��= :` \�� !_i �•?p i`.. 1,•\ �`�.;. "t rji ;'r -:•` �r�� • \-.�, \, .� ._, \`,i�•ii.\ \�\ •� ` l !' �'•;Y..:r 71/5;, yi ___ \',� l i N ?'`U:\, Jji`•V�� , \ ',,` r:-� j�� • . �\ ' \ ' . `1 , 1 , ' "'''i �::---- U��j,l \.`:`y :� \'�.i ` >'�F,\ ���^j: T, C.• �; I/ .%� \lt \ .�t - ... (''} �),-i ,•mac r i " ��. _i _ .'!^f' •'�.,'t '�) r- � i i.. is \ �-Y J t': 'c -- .�:. � . 5 � :t• �;t —. �, ... C ' i ..: e-_: ' :::..:..:.............11 `• •`' . �` Vit._; .•'� >�`_— 1 ,�' > , �:_%_— <� C.�F '`'' i ;-• -_� � _cam'' -%i' `!`'' ���=i'=:�-f j r �^�j / t :� ,�� t �- \\ 33 Figure 1 - Site Location Base Map: USGS 7-1/2' Bowen Residence Quadrangle Maps Lot 21, Tract 27728, Banfield Drive Scale: 1" - 2,000' Project No.: 08617-01 N Earth Systems I 0 2,000 4,000 1r Southwest A V, LEGEND Approximate Boring Location N (Not to Scale) Figure 2 - Boring Locations Bowen Residence Lot 21, Tract 27728, Banfield Drive Project No.: 08617-01 QMOR Earth Systems Southwest I , Bowen Residence Table 1 Fault Parameters & & Deterministic Frtimates of Mean Peak Grnond Accelerntinn (PGAI 08617-01 Fault Name or Seismic Zone Distance from Site (mi) (km) Fault Type UBC Maximum Magnitude Mmax (Mw) Avg Slip Rate (-m/yr) Avg Return Period (yrs) Fault Length (km) Date of Last Rupture (year) Largest Historic Event >5.5M (year) Mean Site PGA, g (g) Reference Notes: (1) (2) (3) (4) 2 (2) (2 (5) (6 San Andreas - Southern (C V +S B M) 9.7 15.6 SS A 7.4 24 220 203 c. 1690 0.31 San Andreas - Mission Crk. Branch 11.3 18.2 SS A 7.1 25 220 95 6.5 1948 0.24 San Andreas - Banning Branch 11.3 18.2 SS A 7.1. 10 220 98 6.2 1986 0.24 San Jacinto (Hot Spgs - Buck Ridge) 12.5 20.2 SS C 6.5 2 354 70 6.3 1937 0.15 San Jacinto-Anza 16.5 26.6 SS A 7.2 12 250 91 5.5 1928 0.18 San Jacinto -Coyote Creek 17.6 28.3 SS B 6.8 4 175 41 1968 6.5 1968 0.13 Blue Cut 19.8 31.8 SS C 6.8 1 760 30 -- O.12 Burnt Mtn. 22.9 36.8 SS B 6.4 0.6 5000 20 1992 6.1 1992 0.08 Eureka Peak 23.9 38.5 SS B 6.4 0.6 5000 19 1992 6.1 1992 0.08 San Jacinto - Borrego 29.7 47.8 SS B 6.6 4 175 29 6.5 1942 0.07 Morongo 33.6 54.0 SS C 6.5 0.6 1170 23 5.5 1947 0.06 Earthquake Valley 35.1 56.4 SS B 6.5 2 351 20 0.05 Pinto Mountain 35.3 56.7 SS B 7.0 2.5 499 73 0.07 Emerson So. - Copper Mtn. 37.3 60.0 SS B 6.9 0.6 5000 54 0.07 San Jacinto -San Jacinto Valley 37.4 60.1 SS B 6.9 12 83 43 6.8 1918 0.07 Landers 38.0 61.2 SS B 7.3 0.6 5000 83 1992 7.3 1992 0.08 Brawley Seismic Zone 38.2 61.5 SS B 6.4 25 24 42 5.9 1981 0.05 Pisgah -Bullion Mtn. -Mesquite Lk 38.9 62.5 SS B 7.1 0.6 5000 88 1999 7.1 1999 0.07 Elsinore -Julian 39.6 63.7 SS A 7.1 5 340 76 0.07 North Frontal Fault Zone (East) 43.9 70.6 DS B 6.7 0.5 1727 27 0.06 Elsinore -Temecula 45.4 73.1 SS B 6.8 5 240 43 0.05 Elsinore -Coyote Mountain 45.7 73.6 SS B 6.8 4 625 39 0.05 Elmore Ranch 45.8 73.8 SS B 6.6 1 225 29 1987 5.9 1987 0.04 Superstition Mtn. (San Jacinto) 48.2 77.6 SS B 6.6 5 500 24 c. 1440 0.04 Johnson Valley (Northern) 48.8 78.6 SS B 6.7 0.6 5000 36 1992 7.3 1992 0.04 Superstition Hills (San Jacinto) 49.3 79.4 SS B 6.6 4 250 23 1987 6.5 1987 0.04 Calico - Hidalgo 50.7 81.6 SS B 7.1 0.6 5000 95 0.05 Lenwood-Lockhart-Old Woman Sprgs 54.3 87.4 SS B 7.3 0.6 5000 145 0.06 North Frontal Fault Zone (West) 55.5 89.3 DS B 7.0 1 1314 50 0.05 San Jacinto -San Bernardino 61.2 98.4 SS B 6.7 12 100 36 6.7 1899 0.03 Elsinore -Glen Ivy 61.3 98.7 SS B 6.8 5 340 36 6.0 1910 0.04 Helendale - S. Lockhardt 61.6 99.1 SS B 7.1 0.6 5000 97 0.04 Weinert (Superstition Hills) 61.7 99.2 SS C 6.6 4 250 22 1987 6.5 1987 0.03 Notes: 1. Jennings (1994) and CDMG (1996) 2. CDMG & USGS (1996), SS = Strike -Slip, DS = Dip Slip 3. ICBO (1997), where Type A faults: Mmax > 7 and slip rate >5 mm/yr &Type C faults: Mmax <6.5 and slip rate < 2 mm/yr 4. CDMG (1996) based on Wells & Coppersmith (1994), Mw =moment magnitude 5. Modified from Ellsworth Catalog (1990) in USGS Professional Paper 1515 6. The estimates of the mean Site PGA are based on the following attenuation relationships: Average of. (1) 1997 Boore, Joyner & Fumal; (2) 1997 Sadigh et al; (3) 1997 Campbell (mean plus sigma values are about 1.6 times higher) Based on Site Coordinates: 33.624 N Latitude, 116.282 W Longtude and Site Soil Type D EARTH SYSTEMS SOUTHWEST ' Earth Systems Southwest 79-81 IB Country Club Drive, Bermuda Dunes, CA 92201 Phone 760 345-1588 Fax 760 345-7315 Boring No: B-1 Drilling Date: April 5, 2002 Project ame: Bowen Residence, The Quarry, La Quinta, CA Drilling Method: 8" HSA File Number: 08617-01 Drill Type: CME 45 w/rope and cathead Boring Location: See Figure 2 Logged By: Karl Harmon v Sample Type Penetration a 3.'� Description of Units Pagel of] o Resistance _ °' q a o Note: The stratification lines shown represent the p Y o E q o approximate boundary between soil and/or rock types Graphic Trend q a o i (Blows/6") rn q U and the transition may be gradational. Blow Count Dry Density oa rn SP -SM SAND AND SILTY SAND: olive -gray, medium ' dense to dense, dry, fine to coarse, some gravel and cobbles 6/13/15 112 2 5 7/11/13 117 2 ] 0 7/9/9 olive, medium dense, damp, fine to medium grained, trace of gravel 15 9/12/12 medium dense, damp 20 6/9/12 Boring completed at 21.5 feet Backfilled with cuttings 25 No groundwater encountered 30 �c ' Earth Systems Southwest 79-81113 Country Club Drive, Bermuda Dunes, CA 92201 Phone 760 345-1588 Fax 760 345-7315 Boring No: B-2 Drilling Date: April 5, 2002 Project Name: Bowen Residence, The Quarry, La Quinta, CA Drilling Method: 8" HSA File Number: 08617-01 Drill Type: CME 45 w/rope and cathead Boring Location: See Figure 2 Logged By: Karl Harmon Sample T e Type Penetration °' " Description of Units Page 1 of 1 _ s ResistanceCIOq a •.2 ami Note: The stratification lines shown represent the Q Y [] (Blows/6" ) T rnQ v c j approximate boundary between soil and/or rock types Graphic Trend o t and the transition may be gradational. Blow Count Dry Density SP -SM SAND AND SILTY SAND: olive -gray, medium dense, damp, fine to coarse grained, some sand and gravel 13/20/21 122 2 5 7/10/13 116 2 olive, medium dense, damp 10 7/10/8 medium dense, damp 15 SM SILTY SAND: olive, medium dense, dry to damp, fine to coarse grained, some sand and silty sand 10/12/13 Boring completed at 18.5 feet 20 Backfilled with cuttings No groundwater encountered 25 30 z� ' Earth Systems Southwest 79-811B Country Club Drive, Bermuda Dunes, CA 92201 Phone (760) 345-1588, Fax (760) 345-7315 Boring No: B-3 Drilling Date: April 5, 2002 ProjectName: Bowen Residence, The Quarry, La Quinta, CA Drilling Method: 8" HSA File Number: 08617-01 Drill Type: CME 45 w/rope and cathead Boring Location: See Figure 2 Logged By: Karl Harmon Sample Type Penetration Description of Units Page 1 of 1 r;; w tj Resistance o E n U q •= aCi Note: The stratification lines shown represent the o q o approximate boundary between soil and/or rock types Graphic Trend q m 0 ($lows/6") to q U and the transition may be gradational. Blow Count Dry Density SP -SM SAND AND SILTY SAND: olive -gray, medium dense, damp, fine. to coarse grained, some sand and silty sand, trace of gravel 5 9/18/18 115 2 SM SILTY SAND: olive -gray, medium, dense, dry to damp, fine to coarse grained, trace of gravel, some 10 sand and silty sand 18/31/21 125 1 SP -SM SAND -AND SILTY SAND: olive, medium dense, damp, fine to coarse grained, some gravel, some 15 7/10/9 sand Boring completed at 16.5 feet Backfilled with cuttings No groundwater encountered 20 25 30 �c . 0 Earth Systems Southwest 79-81113 Country Club Drive, Bermuda Dunes, CA 92201 Phone (760) 345-1588• Fax (760) 345-7315 Boring No: B-4 Drilling Date: April 5, 2002 ProjectName: Bowen Residence, The Quarry, La Quinta, CA Drilling Method: 8" HSA File Number: 08617-01 Drill Type: CME 45 w/rope and cathead Boring Location: See Figure 2 Logged By: Karl Harmon Sample Te Type Penetration "� Description of Units Page 1 of 1 s Resistance U Cn q •= Note: The stratification lines shown represent the QT a o approximate boundary between soil and/or rock types Graphic Trend q (Blows/6") N q U and the transition may be gradational. Blow Count Dry Density SP -Slut SAND AND SILTY SAND: olive -gray, dense, dry to damp, fine to coarse grained, some sand and silty sand, some gravel 11/17/25 96 2 5 olive -gray, medium dense to dense, damp, some gravel 19/21/23 121 2 10 olive -gray, medium dense, damp, fine to coarse grained, 8/$/$ some sand, trace of gravel 15 Boring completed at 14.5 feet Backfilled with cuttings No groundwater encountered 20 25 30 zc APPENDIX B Laboratory Test Results EARTH SYSTEMS SOUTHWEST File No.: 08617-01 May 20, 2002 UNIT DENSITIES AND MOISTURE CONTENT ASTM D2937 & D2216 Job Name: Bowen Residence, The Quarry Sample Location Depth (feet) Unit Dry Density (pcf) Moisture Content (%) USCS Group Symbol BI 5 117 2 SP -SM BI 3 112 2 SP -SM BI 5 117 2 SP -SM B2 2 122 2 SP -SM B2 7 116 2 SP -SM B3 5 115 2 SP -SM B3 10 125 1 SM B4 3 96 2 SP -SM B4 8 121 2 SP -SM r EARTH SYSTEMS SOUTHWEST File No.: 08617-01 May 20, 2002 PARTICLE SIZE ANALYSIS ASTM D-422 Job Name: Bowen Residence, The Quarry Sample ID: B1 @ 0-2' Feet Description: Sand: F to C w/ Gravel (SP -SM) Sieve Percent Size Passing 1-1/2" 100 1" 100 3/4" 98 1/2" 98 3/8" 96 #4 91 #8 82 #16 61 #30 41 #50 25 #100 15 #200 10 % Gravel: 9 % Sand: 81 % Silt: 6 % Clay (3 micron): 4 (Clay content by short hydrometer method) WHO, 11 III 11 1 iu EARTH SYSTEMS SOUTHWEST 1, y File No.: 08617-01 May 20, 2002 ' PARTICLE SIZE ANALYSIS ASTM D-422 ' Job Name: Bowen Residence, The Quarry Sample ID: B3 @ 5' Feet Description: Sand: F to C w/ Gravel (SP -SM) 1 Sieve Percent iSize Passing 1-1/2" 100 1" 100 3/4" 100 ' 1/2" 100 3/8" 98 #4 94 ' #8 83 #16 67 % Gravel: 6 #30 43 % Sand: 86 t#50 22 % Silt: 5 #100 12 % Clay (3 micron): 3 ' #200 8 (Clay content by short hydrometer method) 100 - ' 90 80 ' 70 60 y y' 50 c d t u a 40 30 ' 20 10 I 0 100 10 1 0.1 0.01 0.001 ' Particle Size ( mm) I! 1 i ' EARTH SYSTEMS SOUTHWEST File No.: 08617-01 May 20, 2002 MAXIMUM DENSITY / OPTIMUM MOISTURE ASTM D 1557-91 (Modified) Job Name: Bowen Residence, The Quarry Procedure Used: A Sample ID: B 1 @ 0-2' Feet Preparation Method: Moist Location: Native Rammer Type: Mechanical Description: Gray Brown: Sand, F to C w/ Gravel (SP -SM) Sieve Size % Retained Maximum Density: 126.5 pcf 3/4" 0.0 Optimum Moisture: 9.5% 3/8" 1.9 #4 8.9 140 135 130 110 105 100 0 5 10 15 20 25 Moisture Content, percent EARTH SYSTEMS SOUTHWEST File No.: 08617-01 SOIL CHEMICAL ANALYSES Job Name: Bowen Residence, The Quarry Job No.: 08617-01 Sample ID: B-1 Sample Depth, feet: 0-2' pH: 8.2 Resistivity (ohm -cm): 1,525 Chloride (Cl), ppm: 88 Sulfate (SO4), ppm: 11 Note: Tests performed by Subcontract Laboratory: Soil & Plant Laboratory and Consultants, Inc. 79-607 Country Club Drive. Bermuda Dunes, CA 92201 Tel: (760) 772-7995 General Guidelines for Soil Corrosivitv May 20, 2002 Chemical Agent Amount in Soil Degree of Corrosivity Soluble 0 -1000 ppm Low Sulfates 1000 - 2000 ppm Moderate 2000 - 5000 ppm Severe > 5000 ppm Very Severe Resistivity 1-1000 ohm -cm Very Severe 1000-2000 ohm -cm Severe 2000-10,000 ohm -cm Moderate 10,000+ ohm -cm Low EARTH SYSTEMS SOUTHWEST