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07-2801 (SFD) Geotechnical Engineering Report1 1 1 1 1 1 1 1 1 1 KRISTI HANSON ARCHITECTS, INC. 72-185 PAINTERS PATH, SUITE A PALM DESERT, CALIFORNIA 92260 GEOTECHNICAL ENGINEERING REPORT PROPOSED CUSTOM-BUILT HOME 53-840 DEL GATO DRIVE LOT I II AT THE TRADITIONS LA QUINTA, CALIFORNIA October 12, 2007 CITY OF LA QUINTA BUILDING & SAFETY DEPT. APPROVED FOR CONSTRUCT © 2007 Earth Systems Southwest Unauthorized use or copying of this document is strictly prolibited without the express written consent of Earth Systems Southwest. File No.: 11253-01 07-10-733 BY. IA%Earth Systems ' f• �Southwest 79-811B Country Club Drive Bermuda Dunes, CA 92203 (760)345-1588 (800) 924-7015 ' FAX (760) 345-7315 October 12, 2007 File No.: 11253-01 ' 07-10-733 Kristi Hanson Architects, Inc. 72-185 Painters Path, Suite A Palm Desert, California 92260 Attention: Ms. Jennifer Wilhelmson ' Project: Proposed Custom -Built Single -Family Residence 53-840 Del Gato Drive Lot 111 at the Traditions ' La Quinta, California Subject: Geotechnical Engineering Report We take pleasure in presenting this geotechnical engineering report prepared for the proposed custom-built single-family residence to be located at 53-840 Del Gato Drive, Lot 111 within the Traditions in the City of La Quinta, Riverside County, California. This report presents our findings and recommendations for site grading and foundation design, incorporating the information provided to our office. The site is suitable for the proposed ' development, provided the recommendations in this report are followed in design and construction. In general, the upper soils should be compacted to improve bearing capacity and reduce the potential for differential settlement. The site is subject to strong ground motion from t the San Andreas fault. 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. This report completes our scope of services in accordance with our agreement, dated September 10, 2007. Other services that may be required, such as plan review and grading observation, are additional services and will be billed according to our Fee Schedule in effect at the time services ' are provided. Unless requested in writing, the client is responsible' for distributing 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 submitted, EARTH SYSTEMS SOUTHWEST v(� t' Karl A. Harmon CE 67812 SER/kah/sls/aj f Distribution: 6/Kristi Hanson Architects, Inc. 1/RC File 2/131) File Reviewed by, Shelton L. Stringer GE 2266, EG 2417 4pROFFS.0, �k �pN L. ST �s� ? c� co l ,n Exp o. � T ;> c� cF 6-3 0 \y j�Ulc�NNI , P / \FCALIFO��i.� i i TABLE OF CONTENTS ' Page EXECUTIVE SUMMARY........................................................................................... ii ' Section 1 INTRODUCTION..............:.............................................................................1 1.1 Project Description....:........................................................................................1 ' 1.2 1.3 Site Description..................................................................................................1 Purpose and Scope of Work...............................................................................2 Section 2 METHODS OF INVESTIGATION...............................................................3 ' 2.1 Field Exploration...............................................................................................3 5.3 Slope Stability of Graded Slopes.............................:.......................................12 STRUCTURES............................................................................................................12 2.2 Laboratory Testing..........................................................:..................................3 ' Section 3 3.1 DISCUSSION................................................................................................4 ... Soil Conditions . ..4 ti•5.4 ' 3.2 Groundwater......................................................................................................4 ' 3.3 3.4 Geologic Setting.................................................................................................4 Geologic Hazards . ..5 Mitigation of Soil Corrosivity on Concrete.....................................................16 3.4.1 Seismic Hazards.....................................................................................5 3.4.2 Secondary Hazards.................................................................................6 3.4.3 Site Acceleration and Seismic Coefficients...........................................7 ' Section 4 Section 5 CONCLUSIONS..............................................................................................9 RECOMMENDATIONS...............................................................................11 SITE DEVELOPMENT AND GRADING..................................................................11 ' 5.1 Site Development — Grading....................................!.......................................11 5.2 Excavations and Utility Trenches....................................................................12 ' 5.3 Slope Stability of Graded Slopes.............................:.......................................12 STRUCTURES............................................................................................................12 Foundations......................................................................................................12 ti•5.4 ' 5.5 5.6 Slabs-on-Grade................................................................................................14 Retaining Walls................................................................................................15 5.7 Mitigation of Soil Corrosivity on Concrete.....................................................16 ' 5.8 Section 6 Seismic Design Criteria.'" N LIMITATIONS AD ADDITIONAL SERVICES....................................18 6.1 Uniformity of Conditions and Limitations.......................................................18 ' 6.2 Additional Services ......................................... .......... 19 REFERENCES ...........................................................................................................20 ' APPENDIX A Figure 1 — Site Location Map Figure 2 — Boring Location Map Table 1 — Fault Parameters 2007 California Building Code (CBC) & 7-05 Seismic Parameters Terms and Symbols used on Boring Logs Soil Classification System Logs of Borings j ' APPENDIX B Laboratory Test Results ' EARTH SYSTEMS SOUTHWEST 71 11 EXECUTIVE SUMMARY Earth Systems Southwest has prepared this executive summary solely to provide a general ' overview of the report. The report itself should be relied upon for information about the findings, conclusions, recommendations, and other concerns. ' The site is located at 53-840 Del Gato Drive, Lot 111 within the Traditions development in the City of La Quinta, Riverside County, California. The proposed development will consist of a single -story custom-built single-family residence with a below grade garage. We assume that the proposed residence may use a combination of construction types, including steel moment frames, masonry walls, and wood -frame, and will be supported by conventional shallow continuous or pad footings. The proposed project may be constructed as planned, provided that the recommendations in this report are incorporated in the final design and construction. Site development will include ' clearing and grubbing of vegetation, site grading, building pad preparation, underground utility installation, and concrete driveway and sidewalks placement. Remedial site grading is recommended to provide uniform support for the foundations. Laboratory testing of the site soils indicate low levels of sulfate and chloride ion content, therefore normal concrete mixes may be used. However, indications are that the onsite soils ' exhibit low resistivity resulting in a severe corrosion potential for buried unprotected metal pipes. Underground utilities and buried metal pipes will require corrosion protection from the surrounding soil. We consider the most significant geologic hazard to the project to be the potential for moderate 1 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 1s located ' in Seismic Zone 4 of the 2001 California Building Code (CBC). Structures should be designed in accordance with the values and parameters given within the CBC. The seismic design parameters are presented in the following table and within the report. J I EARTH SYSTEMS SOUTHWEST 111 SUMMARY OF RECOMMENDATIONS Design Item Recommended Parameter Reference Section No. Foundations Allowable Bearing Pressure Continuous wall footings Pad (Column) footings 1,500 psf 5.4 2,000 psf Foundation Tye Spread Footing 5.4 Bearing Materials Engineered fill Allowable Passive Pressure 250 psf per foot 5.4 Active Pressure 35 pcf 5.6 At -rest Pressure 55 pcf 5.6 Allowable Coefficient of Friction 0.35 5.4 Soil Expansion Potential Very low (EI<20) 3.1 Geologic and Seismic Hazards Liquefaction Potential Negligible 3.4.2 Significant Fault and Magnitude San Andreas, M7.7 3.4.3; 5.8 Fault Tye A 3.4.3; 5.8 Seismic Zone 4 3.4.3; 5..8 Soil Profile Tye Sc 3.4.3; 5.8 .Near -Source Distance 14.1 km 3.4.3; 5.8 Near Source Factor, Na 1.00 3.4.3; 5.8 Near Source Factor, N,, 1.04 3.4.3; 5.8 Slabs Building Floor Slabs On engineered fill 5.5 Modulus of Subgrade Reaction 200 pci 5.5 Existing Site Conditions Existing Fill Engineered Soil Corrosivity low sulfates low chlorides very severe metal loss resulting from low resistivity 5.7 Groundwater Depth > 100 ft. 3.2 Estimated Fill and Cut (includes over -excavation) < 2 feet — fill 11 feet —cut (garage) 1.1 The recommendations contained within this report are subject to the limitations presented in Section 6 of this report. We recommend that all individuals using this report read the limitations. EARTH SYSTEMS SOUTHWEST October 12, 2007 1 File No.: 11253-01 GEOTECHNICAL ENGINEERING REPORT 07-10-73 3 PROPOSED CUSTOM-BUILT HOME ' 53-840 DEL GATO DRIVE LOT 111 AT THE TRADITIONS LA QUINTA, CALIFORNIA ' Section 1 INTRODUCTION t1.1 Project Description This geotechnical engineering report has been prepared for the proposed custom-built single- family home to be located at 53-840 Del Gato Drive within the Traditions development in the City of La Quinta, Riverside County, California. ' The proposed development will consist of a one-story single-family residence with a below -grade garage. We assume that the proposed residence may use a combination of construction types, including steel moment frames, masonry walls, and wood -frame, and will be supported by ' conventional shallow continuous or pad footings. Site development will include clearing and grubbing of vegetation, site grading, building pad preparation, underground utility installation, and concrete driveway and sidewalks placement. ' Based on existing site topography and ground conditions, site grading is expected to be minimal, except for the excavation for the subterranean garage and pool. ' We used maximum column loads of 30 kips and a maximum wall loading of 1.5 kips per linear foot as a basis for the foundation recommendations. All loading is assumed to be dead plus actual live load. If actual. structural loading exceeds these assumed values, we would need to ' reevaluate the given recommendations. 1.2 Site Description ' The proposed custom home is to be constructed on a vacant lot on the north side of Del Gato Drive, within the Traditions in the City of La Quinta, California. The site location is shown on Figure 1 in Appendix A. The project site consists of an irregular shaped parcel that has been previously mass graded in conjunction with development of the tract. The proposed home site is relatively flat and elevated ' above the roadway and adjacent golf course at an elevation of approximately 140 feet above mean sea level. The site is covered by a maintained grass lawn with temporary underground irrigation system. The site is bounded by Del Gato Drive to the south, existing homes to the east and west, and the golf course to the north. The east and west parcel boundaries are defined by existing masonry ' walls. There may be underground utilities near and within the building area. These utility lines may include, but are not limited to, domestic water, electric, sewer, telephone, cable, and irrigation I lines. ' EARTH SYSTEMS SOUTHWEST October 12, 2007 2 File No.: 11253-01 ' 07-10-733 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. ➢ Shallow subsurface exploration by drilling five exploratory borings to depths ranging ' from 10 to 31.5 feet below existing grade. ➢ Laboratory testing of selected soil samples obtained from the exploratory borings. ➢ A review of selected published technical literature pertaining to the site and previous geotechnical reports prepared by ESSW for similar projects in the vicinity. ➢ An 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. • 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. ' ➢ An 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. The client did not direct ESSW to provide any service to investigate or detect the presence of moisture, mold, or other biological contaminates in or around any structure, or any service that was designed or intended to prevent or lower the risk or the occurrence of the amplification of ' the same. Client acknowledges that mold is ubiquitous to the environment, with mold amplification occurring ,when building materials are impacted by moisture. Client further acknowledges that site conditions are outside of ESSW's control and that mold amplification will ' likely occur or continue to occur in the presence of moisture. As such, ESSW cannot and shall not be held responsible for the occurrence or recurrence of mold amplification. I EARTH SYSTEMS SOUTHWEST October 12, 2007 3 File No.: 11253-01 - 07-10-733 Section 2' ' METHODS OF INVESTIGATION 2.1 Field Exploration Five exploratory borings were drilled to depths ranging from about 10 to 31.5 feet below the existing ground surface to observe the soil profile and to obtain samples for laboratory testing. ' The borings were drilled on September 13, 2007 using 8 -inch outside diameter hollow -stem augers, powered by a Simco 2800 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 exploration. The final logs are included in Appendix A of this report. The stratification lines represent the approximate boundaries between soil types, although the transitions 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 tother standardized methods as referenced below. Our testing program consisted of the following: ➢ In-situ Moisture Content and Unit Dry Weight for the ring samples. ➢ Maximum density tests to evaluate the moisture -density relationship of typical soils ' encountered. ➢ Particle Size Analysis to classify and evaluate soil composition. The gradation ' characteristics of selected samples were made by hydrometer and sieve analysis procedures. ' ➢ Chemical Analyses (Soluble Sulfates and Chlorides, pH, and Electrical Resistivity) to evaluate the potential adverse effects of the soil on concrete and steel. I EARTH SYSTEMS SOUTHWEST October 12, 2007 4 File No.: 11253-01 07-10-733 Section 3 ' DISCUSSION 3.1 Soil Conditions ' The field exploration indicates that site soils consist generally of dense, fine to coarse grained or Sand with Some Silt to Silty Sand (SM and SP -SM in accordance with the Unified Soil Classification System) with some gravels and occasional cobbles. The depth of transition from artificial fill to native soils could not readily be determined in the borings. Three of the borings were terminated at auger refusal depths ranging from about 10 to 26 feet below grade. Auger ' refusal may have been caused by cobbles, boulders, or bedrock. 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 (EI < 20) category in accordance with Table 18A -I -B of the California Building Code. Site soils are generally classified as Type C in accordance with CalOSHA. In and climatic regions, granular soils may have a potential to collapse upon wetting. Collapse (hydroconsolidation) may occur when the soluble cements (carbonates) in the soil matrix ' dissolve, causing the soil to densify from its loose configuration from deposition. The hydroconsolidation potential is commonly mitigated by recompaction of a zone beneath building pads. The site lies within a recognized blow sand hazard area. Fine particulate matter (PMio) can create an air quality hazard if dust is blowing. Watering the surface, planting grass or ' landscaping, or placing hardscape normally mitigates this hazard. 3.2 Groundwater ' Free groundwater was not encountered in the borings during exploration. The depth to groundwater in the area is believed to be greater than 100 feet. Groundwater levels may fluctuate ' with precipitation, irrigation, drainage, regional pumping from wells, and site grading. Groundwater should not be a factor in design or construction at this site. ' 3.3 Geologic Setting 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 approximately 180 miles from the San Gorgonio Pass 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 part of the Salton Trough. The Coachella Valley ' contains a thick sequence of Miocene to Holocene sedimentary deposits. 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 I EARTH SYSTEMS SOUTHWEST October 12, 2007 5 File No.: 11253-01 07-10-733 granitic rocks. The San Andreas fault zone within the Coachella Valley consists of the Garnet I' Hill fault, the Banning fault, and the Mission Creek fault that traverse along the northeast margin of the valley. ' Local Geology: The project site is located within the La Quinta cove area in the southeast part of the Coachella Valley on the flanks of the Santa Rosa Mountains. The sediments within the valley consist of fine- to coarse-grained sands with interbedded clays, silts, gravels, and cobbles of alluvial (water -laid) origin. Depths -to granitic bedrock in the vicinity of the site may be relatively shallow. ' 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), slope instability, flooding, ground subsidence, and erosion. A discussion follows on the specific hazards to this site. 3.4.1 Seismic Hazards 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 ground shaking from earthquakes along the San Andreas and San Jacinto faults. The Maximum Magnitude Earthquake (Morax) listed is from published geologic information available for each fault (Cao et al., CGS, 2003). The Mmax corresponds to the maximum earthquake believed to be tectonically possible. Surface Fault Rupture: The project site does not lie within a currently delineated State of California, Alquist-Priolo Earthquake Fault Zone (Hart, 1997). Well -delineated fault lines cross through this region as shown on California Geological Survey (CGS) maps (Jennings, 1994); however, no active faults are mapped in the immediate vicinity of the site. Therefore, active fault rupture is unlikely to occur at the project site. While fault rupture would most likely occur along previously established fault traces, future fault rupture could occur at other locations. Historic Seismicity: Six historic seismic events (5.9 M or greater) have significantly affected the Coachella Valley in the last 100 years. They are as follows: • Desert Hot Springs Earthquake — On December 4,' 1948, a magnitude 6.5 ML (6.OMW) earthquake occurred east of Desert Hot Springs. This event was strongly felt in.the Coachella Valley area. • Palm Springs Earthquake - A magnitude 5.9 ML (6.2MW) earthquake occurred on July 8, 1986 in the Painted Hills, causing,minor surface creep of the Banning segment of the San Andreas fault. This event was strongly felt in the Coachella Valley area and caused structural damage, as well as injuries. • Joshua Tree Earthquake — On April 22, 1992, a magnitude 6.1 ML (6.1MW) earthquake occurred in the mountains 9 miles east of Desert Hot Springs. Structural damage and minor injuries occurred in the Coachella Valley area as a result of this earthquake. EARTH SYSTEMS SOUTHWEST October 12, 2007 6 File No.: 11253-01 ' 07-10-733 • Landers and Big Bear Earthquakes — Early on June 28, 1992, a magnitude 7.5 Ms (7.3MW) earthquake occurred near Landers, the largest seismic event in Southern California for 40 years. Surface rupture occurred just south of the town of Yucca Valley and extended some 43 miles toward Barstow. About three hours later, a magnitude 6.6 Ms (6.4MW) ' earthquake occurred near Big Bear Lake. No significant structural damage from these earthquakes was reported in the Coachella Valley area. • Hector Mine Earthquake — On October 16, 1999, a magnitude 7.1 MW earthquake occurred on ' the Lavic Lake and Bullion Mountain faults north of Twentynine Palms. While this event was widely felt, no significant structural damage has been reported in the Coachella Valley. Seismic Risk: While accurate earthquake predictions are not possible, various agencies have conducted statistical risk analyses. In 2002, the California Geological Survey (CGS) and the United States Geological Survey (USGS) completed the latest generation of probabilistic seismic hazard maps. We have used these maps in our evaluation of the seismic risk at the site. The Working Group of California Earthquake Probabilities (WGCEP, 1995) estimated a 22% ' conditional probability that a magnitude 7 or greater earthquake may occur between 1994 and 2024 along the Coachella segment of the San Andreas fault. ' The primary seismic risk at the site is a potential earthquake along the San Andreas fault. Geologists believe that the San Andreas fault has characteristic earthquakes that result from rupture of each fault segment. The estimated characteristic earthquake is magnitude 7.7 for the Southern Segment of the fault (USGS, 2002). This segment has the longest elapsed time since rupture of any part of the San Andreas fault. The last rupture occurred about 1690 AD, based on dating by the USGS near Indio (WGCEP, 1995). This segment has also ruptured on about 1020, ' 1300, and 1450 AD, with an average recurrence interval of about 220 years. The San Andreas fault may rupture in multiple segments, producing a higher magnitude earthquake. Recent paleoseismic studies suggest that the San Bernardino Mountain Segment to the north and the Coachella Segment may have ruptured together in 1450 and 1690 AD (WGCEP, 1995). 3.4.2 Secondary Hazards 1 Secondary seismic hazards, related to ground shaking include soil liquefaction, ground subsidence, tsunamis, and seiches. The site is far inland, so the hazard from tsunamis is non- existent. At the present time, no water storage reservoirs are located in the immediate vicinity of the site. Therefore, hazards from seiches are considered negligible at this time. 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 100 feet. No free groundwater was encountered in our ' exploratory borings. . Ground Subsidence: The potential for seismically induced ground subsidence is considered to be ' very low at the site. Dry sands tend to settle and densify when subjected to strong earthquake shaking. The amount of subsidence is dependent on relative density of the soil, ground motion, ' EARTH SYSTEMS SOUTHWEST 7� October 12, 2007 7 File No.: 11253-01 07-10-733 and earthquake duration. Uncompacted fill areas may be susceptible to seismically induced settlement. Sloe Instabili : The site is relatively flat. Therefore, potential hazards from slope instability, ' landslides, or debris flows are considered negligible. Flooding: The project site does not lie within a designated FEMA 100 -year flood plain. The ' project site may be in an area where sheet flooding and erosion could occur: If significant changes are proposed for the site, appropriate project design, construction, and maintenance can minimize the site sheet flooding potential. ' 3.4.3 Site Acceleration and Seismic Coefficients ' Site Acceleration: The potential intensity of ground motion may be estimated by the horizontal peak ground acceleration (PGA), measured in "g" forces. Included in Table 1 are deterministic estimates of site acceleration from possible earthquakes at nearby faults. Ground motions are ' dependent primarily on the earthquake magnitude and distance to the seismogenic (rupture) zone. Accelerations are also dependent upon attenuation by rock and soil deposits, direction of rupture, and type of fault. For these reasons, ground motions may vary considerably in the same general area. This variability can be expressed statistically by a standard deviation about a mean relationship. The PGA alone is an inconsistent scaling factor to compare to the CBC Z factor and is generally a poor indicator of potential structural damage during an earthquake. Important factors influencing the structural performance are the duration and frequency of strong ground motion, ' local subsurface conditions, soil -structure interaction, and structural details. The following table provides the probabilistic estimate of the PGA taken from the ' 2002 CGS/USGS seismic hazard maps. Estimate of PGA from 2002 CGS/USGS Probabilistic Seismic Hazard Mans Risk Equivalent Return I Period (years) PGA (g) t 10% exceedance in 50 years 1 475 z 0.47 ' Notes: . I Based on a soft rock site, SBic, and soil amplification factor of 1.0 for Soil Profile Type Sc. 2001 CBC Seismic Coefficients: The California Building Code (CBC) seismic design criteria ' are based on a Design Basis Earthquake (DBE) that has an earthquake ground motion with a 10% probability of occurrence in 50 years. The PGA estimate given above is provided for ' information on the seismic risk inherent in the CBC design. The seismic and site coefficients given in Chapter 16 of the 2001 California Building Code are provided in Section 5.8 of this report and below. 1 EARTH SYSTEMS SOUTHWEST October 12, 2007 8 File No.: 11253-01 1. 07-10-733 2001 CBC Seismic Coefficients for Chapter 16 Seismic Provisions EARTH SYSTEMS SOUTHWEST Reference Seismic Zone: 4 Figure 16-2 Seismic Zone Factor, Z: 0.4 Table 16-I Soil Profile Type: Sc Table 16-J Seismic Source Type: A Table 16-U Distance to Known Seismic Source: 14.1 km = 8.7 miles (San Andreas fault) Near Source Factor, Na: 1.00 Table 16-S Near Source Factor, N,,: 1.04 Table 16-T Seismic Coefficient, Ca: 0.40 = 0.40Na Table 16-Q Seismic Coefficient, C,,: 0.58 = 0.56N,, Table 16-R Seismic Hazard Zones: The site lies in a low liquefaction potential zone designated by the 2003 Riverside County Integrated Project because of deep groundwater (>100 feet), and high susceptibility sediments. This portion of Riverside County has not been mapped by the California Seismic Hazard Mapping Act (Ca. PRC 2690 to 2699). 2007 CBC Seismic Coefficients: The 2007 California Building Code (CBC) seismic and site coefficients are given in Appendix A. The 2007 CBC uses the 2006 IBC as the new model code, which adopts'ASCE 7705 by reference, and becomes effective January 1, 2008. EARTH SYSTEMS SOUTHWEST 71 October 12, 2007 9 File No.: 11253-01 07-10-733 Section 4 ' 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. General: ➢ From a geotechnical perspective, the site is suitable for the proposed development, provided the recommendations in this report are followed in the design and construction ' of this project. 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 and earthquake - resistant construction increase safety and allow development of seismic areas. ' ➢ The project site is in seismic Zone 4, is of soil profile Type So, and is about 14 km from a Type A seismic source as defined in the California Building Code. A qualified ' professional should design any permanent structure constructed on the site. The minimum seismic design should comply with the 2001 edition of the California Building Code. ' ➢ Adherence to the grading and structural recommendations in this report should reduce potential settlement problems from seismic forces, heavy rainfall or irrigation, flooding, and the weight of the intended structures. ' ➢ 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. Site grading should be in strict compliance with the requirements of the South Coast Air Quality Management District (SCAQMD). ' ➢ Other geologic hazards, including fault rupture, liquefaction, seismically induced flooding, and landslides, are considered low or negligible on this site. ' ➢ Artificial fills and native soils beneath the site were found to contain some oversized rocks, apparently consisting of cobbles and small boulders. However, larger boulders may exist. Oversize rocks (6 -inch diameter and greater) are not un -common in the native ' alluvial soils in the project vicinity. Oversize rock may require special handling and/or disposal during grading. ➢ Based on blow count resistance and dry densities, the upper soils were found to generally consist of dense sands and should be suitable in their present condition to support structures, fill, and hardscape. The soils within the building and structural areas will ' require moisture conditioning prior to precise grading. No additional compaction is I EARTH SYSTEMS SOUTHWEST October 12, 2007 10 File No.: 11253-01 07-10-733 anticipated at this time. Footing excavations should be observed and tested by a representative of ESSW prior to placing reinforcing steel or form boards. Soils can be readily cut by normal grading equipment. ➢ Excavation of the subterranean garage in not anticipated to encounter bedrock based on a successful 31.5 feet deep boring in the vicinity of the proposed garage. However, shallower bedrock knobs can not be ruled out due to the anticipated un -even nature of the below -grade bedrock surface in the site vicinity. EARTH SYSTEMS SOUTHWEST October 12, 2007 11 File No.: 11253-01 1 • 07-10-733 Section 5 ' RECOMMENDATIONS SITE DEVELOPMENT AND GRADING 5.1 Site Development — Grading ' A representative of Earth Systems Southwest (ESSW) should observe site clearing, grading, and the bottoms of excavations before placing fill. Local variations in soil conditions may warrant increasing the depth of recompaction and over -excavation. Clearing and Grubbing: At the start of site grading, any existing vegetation and abandoned underground utilities 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. Dust control should also be implemented during construction. Site grading should be in strict compliance with the requirements of the South Coast Air Quality Management District (SCAQMD). t Building Pad Preparation: The footings should be excavated to the designed depth. The resulting building pad subgrade should be moisture conditioned and observed and tested to verify the presence of 90% relative compaction. If soft or loose areas are encountered, supplemental compactive effort will be required to provide at least 2 feet of moisture conditioned and compacted soil beneath the bottoms of the footings. ' Auxiliary Structures Subgrade Preparation: Auxiliary structures such as garden or retaining walls should have the foundation subgrade prepared similar to the building pad recommendations given above. ' 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 1 foot below finished subgrades. Compaction should be verified by testing. ' 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 needed) 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 October 12, 2007 12 File No.: 11253-01 07-10-733 Shrinkage: The upper, previously compacted soils ate anticipated to shrink less than 5 percent. ' This estimate is based on compactive effort to achieve an average relative compaction of about 92% and may vary with contractor methods. Losses from site clearing and removal of existing site improvements may affect earthwork quantity calculations and should be considered. ' Site Drainage: Positive drainage should be maintained away from the structures (5% for 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 ' 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 and equal to the depth of the excavation. ' Utility Trenches: Backfill of utilities within roads 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 ' operations should be observed and tested to monitor compliance with these recommendations. 5.3 Slope Stability of Graded Slopes ' 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 of the expected minimal slope heights (less than 5 feet). ' STRUCTURES In our professional opinion, structure foundations can be supported on shallow foundations bearing on a zone of properly prepared and compacted soils placed as recommended in Section 5.1. The recommendations that follow are based on very low expansion category soils. ' 5.4 Foundations ' 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. ' EARTH SYSTEMS SOUTHWEST October 12, 2007 13 File No.: 11253-01 ' 07-10-733 A minimum footing depth of 12 inches below lowest adjacent grade should be maintained. A ' representative of ESSW should observe foundation excavations before placement of reinforcing steel or concrete. Loose soil or construction debris should be removed from footing excavations before placement of concrete. 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 foundations, 12 -inch minimum width and 12 inches below grade: ' 1500 psf for dead plus design live loads Allowable increases of 300 psf per each foot of additional footing width and 300 psf for each additional 0.5 foot of footing depth may be used up to a maximum value of 3000 psf. ' ➢ Isolated pad foundations, 2 x 2 foot minimum in plan and 18 inches below grade: 2000 psf for dead plus design live loads ' Allowable increases of 200 psf per each foot of additional footing width and 400 psf for each additional 0.5 foot of footing depth may be used up to a maximum value of 3000 psf. ' A one-third ('/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 (as specified in the California Building Code) should be two No. 4 steel reinforcing bars, one placed near the top and one placed near the bottom of the footing. This reinforcing is not intended to supersede any structural requirements provided by the structural engineer. Expected Settlement: Estimated total static settlement should be less than 1 inch, based on ' footings founded on firm soils as recommended. Differential settlement between exterior and interior bearing members should be less than '/2 inch, expressed in a post -construction angular ' distortion ratio of 1:480 or less. Frictional and Lateral Coefficients: Lateral loads may be resisted by soil friction on the 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 250 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 by one-third. 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 backfill next to foundations is properly compacted. I EARTH SYSTEMS SOUTHWEST 1 October 12, 2007 14 File No.: 11253-01 07-10-733 5.5 Slabs -on -Grade Sub rg ade: Concrete slabs -on -grade and flatwork should be supported by compacted soil placed in accordance with Section 5.1 of this report. ' Vapor Retarder: In areas of moisture sensitive floor coverings, an appropriate vapor retarder should be installed to reduce moisture transmission from the subgrade soil to the slab. For these ' areas, an impermeable membrane (10 -mil thickness) should underlie the floor slabs. The membrane should be covered with 2 inches of sand to help protect it during construction and to aid 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 membrane is dependent upon its quality, the method of overlapping, its protection during construction, and the successful sealing of the membrane around utility lines. ' The following minimum slab recommendations are intended to address geotechnical concerns such as potential variations of the subgrade and are not to be construed as superseding any ' structural design. The design engineer and/or project architect should ensure compliance with SB800 with regards to moisture and moisture vapor. ' Slab Thickness and Reinforcement: Slab thickness and reinforcement of slabs -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 to resist 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. ' 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 ('/4 of slab depth) within 8 hours of concrete placement. Construction (cold) joints should consist of thickened butt joints with '/2 -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. 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 affected by temperature, wind, and humidity. Quality control procedures may be ' EARTH SYSTEMS SOUTHWEST 71 October 12, 2007 15 File No.: 11253-01 07-10-733 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. ' 5.6 Retaining Walls 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 1 Granular Backfill Passive Pressure 375 pcf - level ground Active Pressure (cantilever walls) Use when wall is permitted to rotate 0.1 to 0.2% of wall 35 pcf - level ground height for granular backfill At -Rest Pressure (restrained walls) 55 pcf - level ground Dynamic Lateral Earth Pressure 2 Acting at 0.6H, 20 pcf Where H is height of backfill in feet Base Lateral Sliding Resistance 0.50 Dead load x Coefficient of Friction: 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 MononobaOkabe 1929 method, additive to active earth pressure. Walls retaining less than 6 feet of soil and not supporting inhabitable structures need not consider this increased pressure (reference: CBC Section 1630A. 1. 1.5). 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. Drainage: A backdrain 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. 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. 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. EARTH SYSTEMS SOUTHWEST I� October 12, 2007 16 File No.: 11253-01 07-10-733 5.7 Mitigation of Soil Corrosivity on Concrete Selected chemical analyses for corrosivity were conducted on soil samples from the project site as shown in Appendix B. The native soils were found to have low sulfate and chloride ion ' concentrations. 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 California Building Code does not require any special provisions for ' concrete for these low concentrations as tested. Normal concrete mixes may be used. A minimum concrete cover of three (3) inches should be provided around steel reinforcing or ' embedded components exposed to native soil or landscape water. Additionally, the concrete should be thoroughly vibrated during placement. ' Electrical resistivity testing of the soil suggests that the site soils may present a severe 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. The information provided above should be considered preliminary. These values can potentially ' change based on several factors, such as importing soil from another job site and the quality of construction water used during grading and subsequent landscape irrigation. ' Earth Systems does not practice corrosion engineering. We recommend that a qualified corrosion engineer evaluate the corrosion potential on metal construction materials and concrete at the site to provide mitigation of corrosive effects, if further guidance is desired. ' 5.8 Seismic Design Criteria I EARTH SYSTEMS SOUTHWEST 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 2001 edition of the California Building Code using the seismic coefficients given in the table below. 2001 CBC 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: Sc Seismic Source Type: A Table 16-J Table 16-U Distance to Known Seismic Source: 14.1 km = 8.7 miles (San Andreas fault) Near Source Factor, Na: 1.00 Table 16-S ' Near Source Factor, N,,: 1.04 Table 16-T Seismic Coefficient, Ca: 0.40 = 0.40Na Table 16-Q ' Seismic Coefficient, C,,: 0.58 = 0.56N,, Table 16-R I EARTH SYSTEMS SOUTHWEST October 12, 2007 17 File No.: 11253-01 ' , 07-10-733 The CBC seismic coefficients are based on scientific knowledge, engineering judgment, and compromise. If further information on seismic design is needed, a site-specific probabilistic seismic analysis should be conducted. ' The intent of the CBC 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 CBC lateral force., requirements should be considered a minimum design. The owner and the designer should evaluate the level of risk and performance that is acceptable. Performance based criteria could be set in -the design.. The. design engineer should exercise special care so that all components of the design are fully met with attention to providing a continuous load path. An adequate quality assurance and control program is urged during project ' construction to verify that the design plans and good construction practices are followed. This is especially important for sites lying close to the major seismic sources. Estimated peak (mean plus one standard deviation) horizontal site accelerations based upon a probabilistic analysis (10% probability of occurrence in 50 years) is approximately 0.47 g for a ' stiff soil site. Actual accelerations may be more or less than estimated. Vertical accelerations are typically `/3 to 2/3 of the horizontal accelerations, but can equal or exceed the horizontal accelerations, depending upon the local site effects and amplification. I EARTH SYSTEMS SOUTHWEST October 12, 2007 18 File No.: 11253-01 07-10-733 Section 6 LIMITATIONS AND ADDITIONAL SERVICES 6.1 Uniformity of Conditions and Limitations rOur 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 the 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 verify 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. I EARTH SYSTEMS SOUTHWEST October 12, 2007 19 File No.: 11253-01 07-10-733 Although available through ESSW, the current scope of our services does not include an environmental assessment or an 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. 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. • A 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 CBC Sections 1701 and 3317 or local grading ordinances. • Consultation as needed during construction. ' -000- ' Appendices as cited are attached and complete this report. F, I EARTH SYSTEMS SOUTHWEST October 12, 2007 20 File No.: 11253-01 t07-10-733 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), 2004, ACI Manual of Concrete Practice, Parts 1 through 5. American Society of Civil Engineers (ASCE), 2006, Minimum Design Loads for Buildings and Other Structures, ASCE 7-05. ' California Department of Water Resources, 1964, Coachella Valley Investigation, Bulletin No. 108, 146 pp. �. California Geologic Survey (CGS), 1997, Guidelines for Evaluating and Mitigating Seismic Hazards in California, Special Publication 117. ' Cao, T, Bryant, W.A., Rowhandel, B., Branum. D., and Wills, C., 2003, The Revised 2002 California Probabilistic Seismic Hazard Maps, California Geologic Survey (CGS), June 2003. Frankel, A.D., et al., 2002, Documentation for the 2002 Update of the National Seismic Hazard Maps, USGS Open -File Report 02-420. Hart, E.W., 1997, Fault -Rupture Hazard Zones in California: California Division of Mines and ' Geology Special Publication 42. International Code Council (ICC), 2002, California Building Code, 2001 Edition. ' International Code Council (ICC), 2007, California Building Code, 2007 Edition. Jennings, CW, 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. Riverside County Planning Department, 2002, Geotechnical Element of the Riverside County General Plan — Hearing Draft. Rogers, T.H., 1966, Geologic Map of California - Santa Ana Sheet, California Division of Mines and Geology Regional Map Series, scale 1:250,000. 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. Wallace, R. E., 1990, The San Andreas Fault System, California: U.S. Geological Survey ' Professional Paper 1515, 283 p. 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 EARTH SYSTEMS SOUTHWEST APPENDIX A Figure 1 — Site Location Map ' Figure 2 — Boring Location Map Table 1 — Fault Parameters 2007 California Building Code (CBC) & 7-05 Seismic Parameters Terms and Symbols used on Boring Logs Soil Classification System Logs of Borings L� 11 I] EARTH SYSTEMS SOUTHWEST All f f R APPENDIX A Figure 1 — Site Location Map ' Figure 2 — Boring Location Map Table 1 — Fault Parameters 2007 California Building Code (CBC) & 7-05 Seismic Parameters Terms and Symbols used on Boring Logs Soil Classification System Logs of Borings L� 11 I] EARTH SYSTEMS SOUTHWEST I n a e•7 7 116'18'45"W 116°18'0"W 116°17'15"W 116°16'30"W 004000 505000 5bb000 5b7000 jL1 . J- . - � • I- • — l ' s . P. e Y h ; •. �' �� • li Q F.: IT. f I . '4 ,�,• �1 r A ?fig\, tl' ° well ALI .nI.i 1 y;3. LS Qu mta...:... TV I••' I\ t V � ^,\l SST (,� ��;',�\�'-1�•r.\� Jj� t � �� - ---_ c==_ccs ' • � , ��,: + ii�\((TT%Cf, `I� +• ' /i `� , q',`1r�� ( l ' { �li .I - - - � -, • !• '� •� lf• ! � \� � \�`.?,�• +8A 'rJj.Z �r/•ii \J� •� 111 i� • I Q• •_ --� (� \�� :\ �.� . t�`��)1�(\- I (� vim:,=-�'�ji �i/% i ',i i. � , ' �•' � t31'Gato=Drive"� ��, �lri� 'r �i{f '' � �� ^ if I !J1 R tl.�i�. .t, •I. / •I• I� -� — ,. ..� �'r.�.1'�� J 7(! it �bjr lam} i � 1 dr�:t...,i W,, 1.2 1• I • S� I• ,/ � (1t1,�� i V 1��1i ��'1 �� F _ll i�� 1�` `,fE�o� e===_=__=_-__= I t S ,,1 • e I .i '_,� ';. �� :f it '3 i ��'• ' � ms=s ---- _= I ��• "f�- -. �� 'i � -L.._ or �' �'7{� lam-' � �II; •�'�� ett<d=-- I f ,�,�� .fir. -, �� • � ,j+~•- �. .� ,l� rJ ?'•' ( ,''i ,G�- I �•. a '•. �� \� 111 i � % ��{ • ! � � \\•. � t i, I.n �Z M p 0 564000 565000 566000 567000 116°18'45"W 11018'0"W 116017'15"W 116°16 30"W 0 500 1,000 2,000 3,000 4,000 5,000 Feet N Figure 1 LEGEND Site Location 53-840 Del Gato Drive QSite Boundary Lot 111 at Traditions, Della Penta Residence La Quinta, Riverside County, California Earth Systems Southwest Reference: www.terraserver-usa.com 10/12/07 File No.: 11253-01 5 1]6o]8'2"W 564800 564850 564900 564950 E 564800 564850 564900 564950 116'18'2"W 0 20 40 80 120 160 200 "Ibmw Feet LEGEND Iti Figure 2 Boring Location Map Approximate Boring Location 53-840 Del Gato Drive Lot 111 at Traditions, Della Penta Residence I Site Boundary La Quinta, Riverside County, California IL ...... Aft, Earth Systems Southwest Reference: www.globexplorer.com 144-0` 1 10/12/07 1 File No.: 11253-01 1 r 11 t G' 11 53-840 Del Gato Drive, La Quinta, CA 11253-01 Table 1 Fault Parameters & Deterministic F,stimates of Mean Peak Ground Acceleration (PGA) Fault Name or . Seismic Zone Distance from Site (mi) (km) Fault Type Maximum Magnitude Mmax (Mw) Avg Slip Rate (mm/yr) Avg Return Period (yrs) Fault - Length (km) Mean Site PCA (g) Reference Notes: 1 (2) (3) (4) 2 2 (2) (5 San Andreas - Southern 8.7 14.0 SS A 7.7 24 220 199 0.31 San Andreas - Banning Branch 9.3 15.0 SS A 7.2 10 220 98 0.26 San Andreas - Mission Crk. Branch 9.3 15.0 SS A 7.2 25 220 95 0.26 San Jacinto (Hot Spgs - Buck Ridge) 13.7 22.1 SS C 6.5 2 354 70 0.13 Blue Cut 17.5 28.2 SS C 6.8 1 760 30 0.13 San Jacinto-Anza 18.0 29.0 SS A 7.2 12 250 91 0.15 San Jacinto -Coyote Creek 18.6 29.9 SS B 6.8 4 175 41 0.12 Burnt Mtn. 20.3 32.7 SS B 6.5 0.6 5000 21 0.09 Eureka Peak 21.5 34.5 SS B 6.4 0.6 5000 19 0.08 Morongo 31.0 49.8 SS C 6.5 0.6 1170 23 0.06 San Jacinto - Borrego 32.2 51.8 SS B 6.6 4 175 29 0.06 Pinto Mountain 32.7 52.6 SS B 7.2 2.5 499 74 0.09 Emerson So. - Copper Mtn. 35.1 56.5 SS B 7.0 0.6 5000 54 0.07 Landers 35.5 57.1 SS B 7.3 0.6 5000 83 0.09 San Jacinto -San Jacinto Valley 35.9 57.8 SS B 6.9 12 83 43 0.07 Earthquake Valley 36.7 59.0 SS B 6.5 2 351 20 0.05 Pisgah -Bullion Mtn. -Mesquite Lk 37.2 59.8 SS B 7.3 0.6 5000 89 0.08 Brawley Seismic Zone 40.4 64.9 SS B 6.4 25 24 42 0.04 Elsinore -Julian 40.8 65.7 SS A 7.1 5 340 76 0.07 North Frontal Fault Zone (East) 41.2 66.3 RV B 6.7 0.5 1727 27 0.07 Elsinore -Temecula 45.4 73.1 SS B 6.8 5 240 43 0.05 Johnson Valley (Northern) 46.3 74.5 SS B 6.7 0.6 5000 35 0.05 Elsinore -Coyote Mountain 48.0 77.2 SS B 6.8 4 625 39 0.05 Elmore Ranch 48.2 77.6 SS B 6.6 1 225 29 0.04 Calico - Hidalgo 48.4 77.9 SS B 7.3 0.6 5000 95 0.06 Superstition Mtn. -(San Jacinto) 50.8 81.8 SS B 6.6 5 500 24 0.04 North Frontal Fault Zone (West) 51.6 83.1 RV B 7.2 1 1314 50 0.07 Lenwood-Lockhart-Old Woman Sprgs 51.7 83.2 SS B 7.5 0.6 5000 145 0.07 Superstition Mills (San Jacinto) 51.9 83.5 SS B 6.6 4 250 23 0.04 Helendale - S. Lockhardt 59.0 95.0 SS B 7.3 0.6 5000 97 0.05 San Jacinto -San Bernardino 59.2 95.2 SS B 6.7 12 100 36 0.04 Elsinore -Glen Ivy 60.2 97.0 SS B 6.8 5 340 36 0.04 Notes: 1. Jennings (1994) and California Geologic Survey (CGS) (2003) 2. CGS (2003), SS = Strike -Slip, RV = Reverse, DS = Dip Slip (normal), BT = Blind Thrust 3. 2001 CBC, where Type A faults: Mmax > 7 & slip rate >5 mm/yr & Type C faults: Mmax <6.5 & slip rate < 2 mm/yr 4. CGS (2003) 5. 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, (4) 1997 Abrahamson & Silva (mean plus sigma values are about 1.5 to 1.6 times higher) Based on Site Coordinates: 33.658 N Latitude, 116.300 W Longtude and Site Soil Type C EARTH SYSTEMS SOUTHWEST 53-840 Del Gato Drive, La Quinta, CA 11253-01 2007 California Building Code (CBC) & ASCE 7-05 Seismic Parameters CBC Reference ASCE 7-05 Reference Seismic Category: D Table 1616.3(1) Table 11.6-1 Site Class: C Table 1615.1.1 Table 20.3-1 Latitude: Sa (g) 33.658 N 0.05 Longitude: 0.10 -116.300 W 1.00 Maximum Considered Earthquake (MCE) Ground Motion Short Period Spectral Response Ss 1.50 g Figure1615(3) 1 second Spectral Response St 0.60 g Figure1615(4) Site Coefficient Fa 1.00 0.47 Table 1615.1.2(1) Site Coefficient FV 1.30 1.40 Table 1615.1.2(2) 1.50 SMs 1.50 g = Fa*Ss 0.31 SM, 0.78 g = Fv*S, Design Earthquake Ground Motion 0.25 Short Period Spectral Reponse SDs 1.00 g = 2/3 * SMs 1 second Spectral Response SDI 0.52 g = 2/3*SM, To 0.10 sec = 0.2*SDI/SDs Ts 0.52 sec = SDI/SDS 2007 CBC (ASCE 7-05) Equivalent Static Response Spectrum 1.2 1.0 rn CU 0.8 0 CU w a) 0.6 U Q CU ` 0.4 U N CL U) 0.0 0.0 0.5 1.0 1.5 2.0 Period (sec) EARTH SYSTEMS SOUTHWEST Figure 22-3 Figure 22.4 Table 11.4-1 Table 11-4.2 Period T (sec) Sa (g) 0.00 0.40 0.05 0.69 0.10 1.00 0.20 1.00 0.30 1.00 0.52 1.00 0.60 0.87 0.70 0.74 0.80 0.65 0.90 0.58 1.00 0.52 1.10 0.47 1.20 0.43 1.30 0.40 1.40 0.37 1.50 0.35 1.60 0.33 1.70 0.31 1.80 0.29 1.90 0.27 2.10 0.25 r r_ s 1 1 11 s DESCRIPTIVE SOIL CLASSIFICATION Soil classification is based on ASTM Designations D 2487 and D 2488 (Unified Soil Classification System). Information on each boring log is a compilation of subsurface conditions obtained from the field as well as from laboratory testing of selected samples. The indicated boundaries between strata on the boring logs are approximate only and may be transitional. SOIL GRAIN SIZE U.S. STANDARD SIEVE 17" 3" 4!d" d 1n An 9nn BOULDERS COBBLES GRAVEL I SAND SILT CLAY COARSE I FINE I COARSE I MEDIUMI FINE 305 76.2 19.1 4.76 2.00 0.42 0.074 SOIL GRAIN SIZE IN MILLIMETERS 0.002 RELATIVE DENSITY OF GRANULAR SOILS (GRAVELS, SANDS, AND NON -PLASTIC SILTS) Very Loose *N=0-4 RD=0-30 - Easily push a 1/2 -inch reinforcing rod by hand Loose N=5-10 RD=30-50 Push a 1/2 -inch reinforcing rod by hand Medium Dense N=11-30 RD=50-70 Easily drive a 1/2 -inch reinforcing rod with hammer Dense N=31-50 RD=70-90 Drive a 1/2 -inch reinforcing rod .1 foot with difficulty by a hammer Very Dense N>50 RD=90-100 Drive a 1/2 -inch reinforcing rod a few inches with hammer *N=Blows per foot in the Standard Penetration Test at 60% theoretical energy. For the 3 -inch diameter Modified California sampler, 140 -pound weight, multiply the blow count by 0.63 (about 2/3) to estimate N. If automatic hammer is used, multiply a factor of 1.3 to 1.5 to estimate N. RD=Relative Density (%). C=Undrained shear strength (cohesion). MOISTURE DENSITY Moisture Condition: An observational term; dry, damp, moist, wet, saturated. Moisture Content: The weight of water in a sample divided by the weight of dry soil in the soil sample CONSISTENCY OF COHESIVE SOILS (CLAY OR CLAYEY SOILS) Very Soft *N=0-1 *C=0-250 psf Squeezes between fingers Soft N=2-4 C=250-500 psf Easily molded by finger pressure Medium Stiff N=5-8 C=500-1000 psf Molded by strong finger pressure Stiff N=9-15 C=1000-2000 psf Dented by strong finger pressure Very Stiff N=16-30 C=2000-4000 psf Dented slightly by finger pressure Hard N>30 C>4000 Dented slightly by a pencil point or thumbnail MOISTURE DENSITY Moisture Condition: An observational term; dry, damp, moist, wet, saturated. Moisture Content: The weight of water in a sample divided by the weight of dry soil in the soil sample expressed as a percentage. Dry Density: The pounds of dry Soil in a cubic foot. MOISTURE CONDITION RELATIVE PROPORTIONS Dry .....................Absence of moisture, dusty, dry to the touch Trace ............. minor amount (<5%) Damp................Slight indication of moisture with/some ...... significant amount Moist.................Color change with short period of air exposure (granular soil) modifier/and... sufficient amount to Below optimum moisture content (cohesive soil) influence material behavior Wet....................High degree of saturation by visual and touch (granular soil) (Typically >30%) Above optimum moisture content (cohesive soil) Saturated .......... Free surface water LOG KEY SYMBOLS PLASTICITY ' Bulk, Bag or Grab Sample DESCRIPTION FIELD TEST Nonplastic A 1/8 in. (3 -mm) thread cannot be rolled at any moisture content. Standard Penetration Split Spoon Sampler Low The thread can barely be rolled. (2" outside diameter) Medium The thread is easy to roll and not much time is required to reach the plastic limit. ' Modified California Sampler (3" outside diameter) High The thread can be rerolled several times after reaching the plastic limit. No Recovery GROUNDWATER LEVEL V Water Level (measured or after drilling) Terms and Symbols used on Boring Log Water Level (during drilling) 1 ILI I. 1 ll 1 u ' GRAPHIC LETTERSYMBOL MAJOR DIVISIONS SYMBOL TYPICAL DESCRIPTIONS Well -graded gravels, gravel -sand CLEAN GW mixtures, little or no fines GRAVELS :: r: r: r:?: '•. < 5% FINES AND ?r• r7• rr• rr• rr• ■ ' GP Poorly -graded gravels, gravel -sand GRAVELLY• �r• :r.•rr•. • ■ • ■ • • ■ mixtures. Little or no fines SOILS r�rrrrrr GM Silty gravels, gravel -sand -silt COARSE More than 50% of GRAVELS GRAINED SOILS coarse fraction WITH FINES > 12% FINES retained on No. 4 GC Clayey gravels, gravel -sand -clay sieve mixtures SW Well -graded sands, gravelly sands, SAND AND CLEAN SAND little or no fines SANDY SOILS (Little or no fines) <5% SP Poorly -graded sands, gravelly More than 50% ofsands, little or no fines material is larger than No. 200 sieve size SAND WITH FINES "' .•:.•:.•:;•:.•:: ' ' ` ' ;: ;: .:.`' "• SM Silty sands, sand -silt mixtures More than 50% of (appreciable -------- coarse fraction amount of fines) passing No. 4 sieve 7 12% SC Clayey sands, sand -clay mixtures Inorganic silts and very fine sands, Im 1111111 ML rock flour, silty low clayey fine sands or clayey silts with slight plasticity LIQUID LIMIT Inorganic clays of low to medium FINE-GRAINED LESS THAN 50 CL plasticity, gravelly clays, sandy SOILS clays, silty clays, lean clays OL Organic silts and organic silty clays of low plasticity SILTS AND CLAYS Inorganic silty, micaceous, or MH diatomaceous fine sand or silty soils 50% or more of material is smaller LIQUID LIMIT CH Inorganic clays of high plasticity, than No. 200 GREATER fat clays sieve size THAN 50 Organic clays of medium to high �. ............. plasticity, organic silts Peat, humus, swamp soils with HIGHLY ORGANIC SOILS y PT high organic contents VARIOUS SOILS AND MAN MADE MATERIALS Fill Materials MAN MADE MATERIALS Asphalt and concrete Soil Classification System Earth Systems '� Southwest ' Earth Systems 1� SouthwestPhone iB Country Club Drive, Bermuda Dunes, CA 92203 Phone (760) 345-1588, Fax (760) 345-7315 t if 1 , d - I t 1 BorinNo' B-1 Drilling Date: September 13, 2007 Project ame: 53-840 Del Gato Drive, La Quinta, CA Drilling Method: 8" Hollow Stem Auger File Number: 11253-01 Drill Type: Simco 2800 w/Auto Hammer Boring Location: See Figure 2 Logged By: Dirk Wiggins Sample Type Penetration °' ° Description of Units Page 1 of 1 aResistance o U C q o _o Y Note: The stratification lines shown represent the ca y A T q it,� o approximate boundary between soil and/or rock types Graphic Trend C) m � 0 (Blows/6") rn q U and the transition may be gradational. Blow Count Dry Density SM SILTY SAND: moderate yellowish brown to dark yellowish brown, medium dense to dense, damp, ' -,12,21 119 3 fine to coarse grained, coarse gravels and cobbles at 3 feet 8,15,16 5 6,10,20 10 few fine gravels 12 13 17 15 6,6,7 medium dense, cobbles @ 15'-16' 20 13,14,12 dark brown, rock fragments, dense 25 6,5,5 medium dense 30 5,5,7 Total Depth 31.5 feet No Groundwater Encountered 35 AA 4 Earth Systems Southwest 79-81113 Country Club Drive, Bermuda Dunes, CA 92203 -5 -10 - 15 - 20 - 25 - 30 - 35 -40 rnone tiov) w�-i Baa, rax tiov) w:) -i.31 i Drilling Date: September 13, 2007 Drilling Method: 8" Hollow Stem Auger Drill Type: Simco 2800 w/Auto Hammer Logged By: Dirk Wiggins Description of Units Page 1 of t Note: The stratification lines shown represent the approximate boundary between soil and/or rock types Graphic Trend and the transition may be gradational. Blow Count Dry Densitv ' 4,5,5 12,24,28 5,11,18 Boring No: B-2 125 124 4 8 ProjectName: 53-840 Del Gato Drive, La Quinta, CA File Number: 11253-01 SP -SM SAND WITH SILT: pale to moderate yellowish Boring Location: See Figure 2 Sample brown, dense to medium dense, damp, fine to coarse o Type Penetration o V) r - a U Resistance E � A (Blows/6") V) A" U S,I0,11 -5 -10 - 15 - 20 - 25 - 30 - 35 -40 rnone tiov) w�-i Baa, rax tiov) w:) -i.31 i Drilling Date: September 13, 2007 Drilling Method: 8" Hollow Stem Auger Drill Type: Simco 2800 w/Auto Hammer Logged By: Dirk Wiggins Description of Units Page 1 of t Note: The stratification lines shown represent the approximate boundary between soil and/or rock types Graphic Trend and the transition may be gradational. Blow Count Dry Densitv ' 4,5,5 12,24,28 5,11,18 SM 125 124 4 8 SILTY SAND: pale to dark yellowish brown, dense to medium dense, damp, fine to coarse grained, few to trace fine gravels SP -SM SAND WITH SILT: pale to moderate yellowish brown, dense to medium dense, damp, fine to coarse 13,19,25 grained, trace gravels 10,12,13 S,I0,11 9,6,7 medium dense, cobbly REFUSAL: cobbles and boulders at 26.5 feet Total Depth 26.5 feet No Groundwater Encountered Earth Systems Southwest 79-81 IB Country Club Drive, Bermuda Dunes, CA 92203 -5 -10 - 15 - 20 - 25 - 30 - 35 -40 rnone tiou) sv-uaa, rax tiou) Drilling Date: September 13, 2007 Drilling Method: 8" Hollow Stem Auger Drill Type: Simco 2800 w/Auto Hammer Logged By: Dirk Wiggins Description of Units Page 1 of I Note: The stratification lines shown represent the approximate boundary between soil and/or rock types Graphic Trend and the transition may be gradational. Blow Count Dry Density Boring B-3 �No: Project Name: 53-840 Del Gato Drive, La Quinta, CA File Number: 11253-01 Boring Location: See Figure 2 Sample dense to very dense, damp, fine to coarse grained, o v Type Penetration o �� B nResistance � Ca Q. _o q N 0 (Blows/6") 5 q Q� j -5 -10 - 15 - 20 - 25 - 30 - 35 -40 rnone tiou) sv-uaa, rax tiou) Drilling Date: September 13, 2007 Drilling Method: 8" Hollow Stem Auger Drill Type: Simco 2800 w/Auto Hammer Logged By: Dirk Wiggins Description of Units Page 1 of I Note: The stratification lines shown represent the approximate boundary between soil and/or rock types Graphic Trend and the transition may be gradational. Blow Count Dry Density SM SILTY SAND: dark yellowish brown, medium dense to very dense, damp, fine to coarse grained, 5,6,6 some fine gravels 8,14,20 T. 125 5 11,14,26 123 6 moderate yellowish brown to white, very dense 12,24,36 4,3,4 medium dense Total Depth 16.5 feet No Groundwater Encountered Earth Systems Southwest 79-81113 Country Club Drive, 13emwda Dunes, CA 92203 -5 -10 - 15 - 20 - 25 - 30 - 35 -40 rnone tiou) ja>i365, rax tiou).s43-isu Drilling Date: September 13, 2007 Drilling Method: 8" Hollow Stem Auger Drill Type: Simco 2800 w/Auto Hammer Logged By: Dirk Wiggins Description of Units JPage I of I Note: The stratification lines shown represent the approximate boundary between soil and/or rock types Graphic Trend and the transition may be gradational. Blow Count Dry Density ® 5,6,10 12,20,13 15,20,26 BorinNo: B-4 SILTY SAND: pale to moderate yellowish brown, medium dense to very dense, damp, fine to coarse grained, cobbles near surface, some fine gravels dense moderate brown, very dense Project ame: 53-840 Del Gato Drive, La Quinta CA File Number: 11253-01 REFUSAL: cobbles and boulders at 10 feet Boring Location: See Figure 2 . Sample Total Depth 10 feet 0 v . Type Penetration No Groundwater Encountered aResistance p E (n Ca n, C) 0 (Blows/6") � A. c �v w' -5 -10 - 15 - 20 - 25 - 30 - 35 -40 rnone tiou) ja>i365, rax tiou).s43-isu Drilling Date: September 13, 2007 Drilling Method: 8" Hollow Stem Auger Drill Type: Simco 2800 w/Auto Hammer Logged By: Dirk Wiggins Description of Units JPage I of I Note: The stratification lines shown represent the approximate boundary between soil and/or rock types Graphic Trend and the transition may be gradational. Blow Count Dry Density ® 5,6,10 12,20,13 15,20,26 SM SILTY SAND: pale to moderate yellowish brown, medium dense to very dense, damp, fine to coarse grained, cobbles near surface, some fine gravels dense moderate brown, very dense REFUSAL: cobbles and boulders at 10 feet Total Depth 10 feet No Groundwater Encountered 1 1 iJ I'll t L� 11, Earth Systems v Southwest 79-811 B Country Club Drive, Bennuda Dunes, CA 92203 Phone (750) 345-1588, Fax (760) 345-7315 Boring NO' B-5 Drilling Date: September 13, 2007 Project ame: 53-840 Del Gato Drive, La Quinta, CA Drilling Method: 8" Hollow Stem Auger File Number: 11253-01 Drill Type: .Simco 2800 w/Auto Hammer Boring Location: See Figure 2 Logged By: Dirk Wiggins Sample Type Penetration ° ' Description of Units IPage 1 of 1 a c9 Resistance o U c q •= SNote: The stratification lines shown represent the Y q T q ° c approximate boundary between soil and/or rock types Graphic Trend q (Blows/6") q U and the transition may be gradational. Blow Count Dry Density SM SILTY SAND: moderate yellowish brown, medium dense to very dense, dry to damp, fine to coarse grained, trace fine gravels 8,28,31 127 5 5 13,24,48 126 5 very dense cobbles below 8 feet 0 dark yellowish brown 15,19,22 dense REFUSAL: cobbles and boulders at 10 feet 15 Total Depth 13 feet No Groundwater Encountered 20 25 30 35 At) t 1 t r 11 t f] I APPENDIX B Laboratory Test Results EARTH SYSTEMS SOUTHWEST File No.: 11253-01 October 12, 2007 Lab No.: 07-0596 UNIT DENSITIES AND MOISTURE CONTENT ASTM D2937 & D2216 Job Name: 53-840 Del Gato, La Quinta B1 1 Unit Moisture USCS Sample Depth Dry Content Group Location (feet) Density (pcf) N Symbol B1 1 119 3 SM B2 3 125 4 SM B2 5 124 8 SM B3 3 125 5 SM B3 5 123 6 SM B5 2.5 127 5 SM B5 5 126 5 SM EARTH SYSTEMS SOUTHWEST File No.: 11253-01 Job Name: 53-840 Del Gato, La Quinta Lab Number: 07-0596 October 12, 2007 AMOUNT PASSING NO. 200 SIEVE ASTM D 1 140 B2 5 16 SM B2 10 10 SP -SM EARTH SYSTEMS SOUTHWEST Fines USCS Sample Depth Content Group Location (feet) N Symbol B2 5 16 SM B2 10 10 SP -SM EARTH SYSTEMS SOUTHWEST File No.: 11253-01 October 12, 2007 Lab No.: 07-0596 PARTICLE SIZE ANALYSIS ASTM D-422 Job Name: 53-840 Del Gato, La Quinta Sample ID: B1 @ 1-4 feet Description: Brown Silty Fine to Coarse Sand w/Gravel (SM) Sieve Percent Size Passing 1-1/2" 100 1" 100 3/4" 98 1/2" 94 3/8" 91 #4 83 #8 71 #16 64 % Gravel: 17 #30 52 % Sand: 67 #50 38 % Silt: 11 #100 25 % Clay (3 micron): 5 #200 16 (Clay content by short hydrometer method) 100 ,-- — -- 90 -- 80 70 °❑° 60 ° 50 c U a 40 30 20 10 0 100 10 1 0.1 0.01 0.001 Particle Size ( mm) EARTH SYSTEMS SOUTHWEST File No.: -11253-01 October 12, 2007 Lab No.: 07-0596 PARTICLE SIZE ANALYSIS ASTM D-422 Job Name: 53-840 Del Gato, La Quinta Sample ID: B3 @ 1-4 feet Description: Brown Silty Fine to Coarse Sand w/Gravel (SM) Particle Size ( mm) EARTH SYSTEMS SOUTHWEST Sieve Percent Size Passing 1-1/2" 100 l" 97 3/4" 95 1/2" 92 3/8"- 89 #4 80 #8 66 #16 59 % Gravel: 20 #30 48 % Sand: 66 #50 34 % Silt: 10 #100 22 % Clay (3 micron): 4 #200 14 (Clay content by short hydrometer method) 100 90 80 70 a 60 i� a' S0 C ti a 40 30 --- 20 10 0 100 10 1 0.1 0.01 0.001 Particle Size ( mm) EARTH SYSTEMS SOUTHWEST File No,.: 11253-01 October 12, 2007 Lab No.: 07-0596 MAXIMUM DENSITY / OPTIMUM MOISTURE ASTM D 1557-91 (Modified) Job Name: 53-840 Del Gato, La Quinta Procedure Used: B Sample ID: 1 Preparation Method: Moist Location: BI @ 1-4 feet Rammer Type: Mechanical Description: Brown Silty Fine to Coarse Sand Lab Numbe 07-0596 w/Gravel (SM) Sieve Size % Retained Maximum Density: 132 pcf 3/4" 8.6 Optimum Moisture: 8.5% 3/8" 18.8 #4 26.2 140 135 130 125 110 105 100 0 5 10 15 20 25 30 35 Moisture Content, percent EARTH SYSTEMS SOUTHWEST File No.: 11253-01 Corrosivity Chemical Agent October 12, 2007 Lab No.: 07-0596 Soluble 0 -1000 mg/Kg (ppm) [ 0-.1%] Low SOIL CHEMICAL ANALYSES 1000 - 2000 mg/Kg (ppm) [0.1-0.2%] Moderate 2000 - 20,000 mg/Kg (ppm) [0.2-2.0%] Severe Job Name: 53-840 Del Gato, La Quinta Very Severe Job No.: 11253-01 Very Severe Sample 1D: BI B3 2000-10,000 ohm -cm Sample Depth, feet: 1-4 1-4 DF RL Sulfate, mg/Kg (ppm): N.D. 17 l 0.50 Chloride, mg/Kg (ppm):' 108 91 1 0.20 pH, (pH Units): 7.70 7.40 1 0.41 Resistivity, (ohm -cm): 1,370 1,700 N/A NIA Conductivity, (µmhos -cm): 1 2.00 Note: Tests performed by Subcontract Laboratory: Surabian AG Laboratory DF: Dilution Factor 105 Tesori Drive RL: Reporting Limit Palm Desert, California 92211 Tel: (760) 200-4498 General Guidelines for Soil Corrosivity Chemical Agent Amount in Soil Degree of Corrosivity Soluble 0 -1000 mg/Kg (ppm) [ 0-.1%] Low Sulfates 1000 - 2000 mg/Kg (ppm) [0.1-0.2%] Moderate 2000 - 20,000 mg/Kg (ppm) [0.2-2.0%] Severe > 20,000 mg/Kg (ppm) [>2.0%] 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