The URL can be used to link to this page

06-3088 (CSCS) Geotechnical Report10/31/2006 09:50 7603457315 PAGE 02/02 ^k Earth Systems Southwest 79-811B Country Club Drive Bermuda Duncs, CA 92203 (760)345.1988 (800)924.7015. FAX (760) 345-7315 j File No.: 10655-01 Qctober 26, 2006 06-10-813 Stamko Development 2205 North Poinsettia Avenue Manhattan Beach, California 90266 Attention: Ms. Christine Clarke Subject: Plan Review Project: Proposed Commercial Development Southwest Comer of Dune Palms Road and Highway 111 'La Quinta, California References: 1..• Earth Systems Southwest, Geotechnical. Engineering Report, Proposed Commercial Development, Southwest Comer of Dune Palms Road and Highway 111, La Quinta, California, File No.: 10655-01, Document No.: 06- 06-767, dated June 12, 2006. 2. ANF & Associates, Project Structural Plans for Retail Sbop Building — Parcel 1, SWC HWY 111 and Dune Palms Road, La Quints, CA, Sheets ST 1, ST2, S1.0 to S5.0, dated ,August 10, 2006. Dear Ms. Clarke: As -required by Mr. Norman Hon of ,ANF & Associate, we have reviewed the geotechnical engineering report prepared by Earth Systems Southwest in conjunction with the project plans. Based on our review of these documents, it is our opinion that the referenced plans are in substantial compliance with the referenced geotechnical engineering report. We make no representation as to the accuracy of the dimensions, measurements, calculations, or any portion of the design. If you have any questions or require additional information, please contact this office at your convenience. Respectfully submitted, Q�oF�SS/oN EARTH SYSTEMS SOUTIAWEST Reviewed C\ CE 38234 M ` / / J'✓, m EV. 03131/07 Hongbiu0. Huo, Ph.D. Craig S. Hil Project.Engineer CE 38234 `jF Crv1L�Q' OF Letter/hh/csh/ajf Distribution: 2/Stamko Development 1 /RC File 21131) File CITY OF LA QUINTA BUILDING & SAFETY DEPT. 1f I� DATE Z(i O BY_!�p/L OCT-31-2006'TUE 09:45, AM 7603457315 P. 02 Earth Systems Southwest CITY OFIA QUINTA BUILDING & SAFETY DEPT. r. rf DATE'y 7q- "dF IL Consulting Engineers and Geologists c 7� i5 �TPI A 2006 STAMKO DEVELOPMENT 2205 NORTH POINSETTIA AVENUE i MANHATTAN BEACH, CALIFORNIA 90266 GEOTECHNICAL ENGINEERING REPORT PROPOSED COMMERCIAL DEVELOPMENT 1 -SOUTHWEST CORNER OF DUNE.PALMS ROAD AND HIGHWAY I11 LA QUINTA, CALIFORNIA ' June 12, 2006 f x ©2006 Earth Systems Southwest Unauthorized use or copying of this document is strictly prohibited without the express written consent of Earth Systems Southwest. File No.: 10655-01 06-06-767 1 n t 1 t 1 Earth Systems '`/ Southwest 79-811B Country Club Drive Bermuda Dunes, CA 92203 (760)345-1588 (800)924-7015 FAX (760) 345-7315 June 12, 2006 Stamko Development 2205 North Poinsettia Avenue Manhattan Beach, California 90266 Attention: Ms. Christine Clarke Subject: Geotechnical Engineering Report Project: Proposed Commercial Development Southwest Corner of Dune Palms Road and Highway 111 La Quinta, California Dear Ms. Clarke: File No.: 10655-01 06-06-767 We take pleasure in presenting this geotechnical engineering report prepared for the proposed commercial development to be located at the southwest corner of Dune Palms'Road and Highway 111 in the City of La Quinta, Riverside County, California. The property is legally described as Assessor's Parcel Number (APN) 600-020-027. 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 site soils should be compacted to improve bearing capacity and reduce the potential for differential settlement. The site is subject to strong ground motion from 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 May 15, 2006. 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 ;)I� Hongbin Ruo, Ph.D. Project Engineer SER/hh/csh/reh Distribution: 3/Stamko Development 3/Perkanitz & Ruth Attn.: Mr. Jim Thury 2/Stantec I/RC File; 2/131D File Reviewed by, Craig S. Hill CE 38234 4�OFESSIpN9 t_. S; 9, y � No. 266 M M Exp. 6-30-0� `sT �40 �� F OF IEARTH SYSTEMS SOUTHWEST 1 TABLE OF CONTENTS Page 1 EXECUTIVE SUMMARY...........................................................................................ii Section 1 INTRODUCTION...........................................................................................1 1.1 Project Description............................................................................................1 1.2 Site Description................................................................................................. l 1.3 Purpose and Scope of Work..............................................................................2 Section 2 2.1 METHODS OF INVESTIGATION...............................................................3 Field Exploration............................................................................................... 3 2.2 Laboratory Testing.............................................................................................3 Section3 DISCUSSION...................................................................................................4 3.1 Soil Conditions..................................................................................................4 3.2 3.3 Groundwater...................................................................................................... Geologic Setting................................................................................................4 4 3.4 Geologic Hazards...............................................................................................5 ' 3.4.1 Seismic Hazards ii.................................................................................... 3.4.2 Secondary Hazards................................................................................6 5 3.4.3 Site Acceleration and Seismic Coefficients...........................................7 Section4 CONCLUSIONS..............................................................................................9 Section 5 RECOMMENDATIONS..............................................................................10 ' SITE DEVELOPMENT AND GRADING.................................................................10 5.1 Site Development — Grading...........................................................................10 5.2 Excavations and Utility Trenches....................................................................11 I 5.3 Slope Stability of Graded Slopes.....................................................................12 STRUCTURES............................................................................................................12 5.4 Foundations.....................................................................................................12 5.5 5.6 Slabs-on-Grade....................................:.........................................................13 Retaining Walls . .14 5.7 Mitigation of Soil Corrosivity on Concrete.....................................................15 ' 5.8 Seismic Design Criteria...................................................................................15 5.9 Pavements........................................................................................................16 Section 6 6.1 LIMITATIONS AND ADDITIONAL SERVICES Uniformity of Conditions and Limitations......................................................18 ....................................18 6.2 Additional Services......................................................................:...................19 ' REFERENCES..........................................................................................................20 APPENDIX A Figure 1 — Site Location Map Figure 2 — Boring Location Map Table 1 — Fault Parameters Terms and Symbols used on Boring Logs Soil Classification System Logs of Borings APPENDIX B , Laboratory Test Results IEARTH SYSTEMS SOUTHWEST 1 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 the southwest corner of Dune Palms Road and Highway 111 in the City of La Quinta, Riverside County, California. The proposed development will consist of a 23,000 ft2 commercial building and parking lot. We understand that the proposed structure will be single -story wood -frame with stucco exterior, steel moment frames, and steel columns supported by pad and perimeter wall foundations with concrete slabs -on -grade. 1 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, street and parking lot construction, and concrete driveway and sidewalks placement. Based on the non-uniform nature and hydrocollapse potential of the near surface soils, remedial site grading is recommended to provide uniform support for the foundations. Site soils exhibited '-low sulfate and chloride concentrations; however, the site soils tested very severe for resistivity. Therefore, special consideration should be give to protecting buried metal pipes. rWe 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 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. t 1 I I EARTH SYSTEMS SOUTHWEST 1 1 1 .1 II t Ii iii SUMMARY OF RECOMMENDATIONS fiVS fl fizy ?Desigri Item ,� * �i*E; ''tr''i��=i=�}}y,}aCt'�fir$Y'K'� dC y \?.Y-+�-+'h� �Sr'�h �f ,'��_+:i!, �'7�y.�` �`::_Z.�'��.�J ^jr �� st.,Rp ecommended Parameter •{1iih1l�l?��; i/'yaylyy�ppk�,F{�'!t' '�) �'R M, ^�i Yi,fE" '� Yl ;i'�'�)Z^/.-e' n. ".�`.�'�{�k�ny�� 'S`{itr,��{hl'�`4}� f.r rencef ,T.1`;Sect�roY."'' Ree{n;No � #'d�'i•�+,ti-i �`�rcw �S;dj F1+��!}_.�'';?d . 4' 4. -'�{'Fj`1 iq�F��'Y-_-`I•'ly'1� � Ff Foundations Allowable Bearing Pressure Continuous wall footings 1,500 psf 5.4 Pad Column footings 2,000 psf Foundation Type Spread Footing 5.4 Bearing Materials Engineered fill Allowable Passive Pressure 250 pcf 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 `J I Negligible, 3.4.2 Significant Fault and Magnitude San Andreas, M7.7 3.4.3; 5.8 Fault Type A 7 3.4.3; 5.8 Seismic Zone 4 3.4.3; 5.8 Soil Profile Type SD 3.4.3; 5.8 Near -Source Distance 8.7 km 3.4.3; 5.8 Near Source Factor!NA-1 C1.051 3.4.3; 5.8 Near Source Factor; Nva 1.31 1 3.4.3; 5.8 Pavement TI equal to 4.5 (Light Traffic) 3.0" AC / 4.0" AB 5.9 TI equal to 7.0 (Heavy Traffic) 4.0" AC / 8.0" AB 5.9 Slabs Building Floor Slabs On engineered fill 5.5 Modulus of Subgrade Reaction 200 pci 5.5 Existing Site Conditions Existing Fill N/A Soil Corrosivity low sulfates low chlorides very severe resistivity (protect buried metal pipes) 5.7 Groundwater Depth > 50 feet 3.2 Estimated Fill and Cut 2 feet - fill and cut 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. I EARTH SYSTEMS SOUTHWEST June 12, 2006 Section 1 INTRODUCTION I GEOTECHNICAL ENGINEERING REPORT PROPOSED COMMERCIAL DEVELOPMENT SOUTHWEST CORNER OF DUNE PALMS ROAD AND HIGHWAY 111 LA QUINTA, CALIFORNIA 1.1. Project Description File No.: 10655-01 06-06-767 This geotechnical engineering report has been prepared for the proposed commercial development to be located at the southwest corner of Dune Palms Road and Highway 111 in the City of La Quinta, Riverside County, California. The property is legally described as Assessor's Parcel Number (APN) 600-020-027. We understand that the proposed 2 -acre development will consist of a 23,000 -square foot (ft) "L" -shaped commercial building. ! The proposed commercial building will be a single -story structure. We understand that the proposed structure will be wood -frame with stucco exterior, steel moment frames, and steel ' columns supported by pad and perimeter wall. foundations with concrete slabs -on -grade. Site development will include clearing and grubbing of vegetation, site grading, building pad preparation, underground utility installation, street and parking lot construction, and concrete driveway and sidewalks placement. Based on existing site topography and ground conditions, site grading is assumed to consist of fills of about 2 feet and cuts of about 3 feet. `. We used maximum column loads of 40 kips and a maximum wall loading of 3 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 1.2 Site Description The proposed commercial development is to be constructed on the southwest corner of Dune Palms Road and Highway 111 in the City of La Quinta, Riverside County, California. The site location is shown on Figure I in Appendix A. The project site presently consists of vacant land and is split-level, being about 5 feet higher in elevation in the northern third of the site. The history of past use and development of the property was not investigated as part of our scope of services. No evidence of past development was observed on the site during our reconnaissance. Nonetheless, some previous development of ' the site is possible. Buried remnants, such as old foundations, slabs, or septic systems, may exist on the site. There are underground utilities near and within the building area. These utility lines include, but are not limited to, domestic water, electric, sewer, telephone, cable, and irrigation lines. EARTH SYSTEMS SOUTHWEST June 12, 2006 2 File No.: 10655-01 ' 06-06-767 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: i ➢ A general reconnaissance of the site. 1 ➢ Shallow subsurface exploration by drilling four exploratory borings to depths ranging from 11.5 to 21.5 feet below existing grade. ➢ Laboratory testing of selected soil samples obtained from the exploratory borings. I➢ A review of selected published technical literature pertaining to the site. ➢ 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. 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. EARTH SYSTEMS SOUTHWEST 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. • Preliminary pavement structural sections. e 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. EARTH SYSTEMS SOUTHWEST June 12, 2006 3 File No.: 10655-01 06-06-767 Section 2 METHODS OF INVESTIGATION 2.1 Field Exploration Four exploratory borings were drilled to depths ranging from 11.5 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 May 22 and 23, 2006 using 8 -inch outside diameter hollow -stem augers, powered by a CME 55 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. t2.2 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. ➢ 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. I ➢ 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 June 12, 2006 4 File No.: 10655-01 ' 06-06-767 Section 3 ' DISCUSSION 3.1 Soil Conditions 1 The field exploration indicates that site soils consist generally of silty sand, poorly graded sand with silt, and silt (Unified Soils Classification System symbols SM, SP -SM, and ML). 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. 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 50 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 ' 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. ' Local Geology: The project site is located approximately 60 feet above mean sea level in the central part of the Coachella Valley. The sediments within the valley consist of fine- to ' EARTH SYSTEMS SOUTHWEST June 12, 2006 5 File No.: 10655-01 ' 06-06-767 coarse-grained sands with interbedded clays, silts, gravels, and cobbles of aeolian (wind-blown), lacustrine (lake -bed), and alluvial (water -laid) 'origin. The depth to crystalline basement rock beneath the site is estimated to be in excess of 2000 feet (Envicom, 1976). ' 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 (Mmax) 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 ro'ect site does not lie within a currently P p ,J 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 Palm Springs 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 Palm Springs 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 Palm Springs area as a result of this earthquake. • 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 Palm Springs area. ' EARTH SYSTEMS SOUTHWEST t June 12, 2006 6 File No.: 10655-01 ' 06-06-767 • Hector Mine Earthquake —On October 16, 1999, a magnitude 7.1MW 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 ' 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 site lies within a moderate liquefaction hazard area established by the 2002 Riverside County General Plan, based on historic high groundwater from 50 to 100 feet and very susceptible ' (Holocene) sediments. Quantitative liquefaction analyses are typically not required for general construction where groundwater depth exceeds 50 feet. The potential for liquefaction to occur at this site is negligible because the existing depth of groundwater beneath the site exceeds 50 feet and is not expected to return to levels above 50 feet. Therefore, no special mitigation for soil liquefaction is warranted for this project.. ' Ground Subsidence: The potential for seismically induced ground subsidence is considered to be 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, and earthquake duration. Uncompacted fill areas may be susceptible to seismically induced settlement. EARTH SYSTEMS SOUTHWEST June 12, 2006 7 File No.: 10655-01 ' 06-06-767 Slope Instability: 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 iv 1 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 Praha hilictir'Reicmie Na7.ard Manc Risk Equivalent Return Period (years) PGA (g)' 10% exceedance in 50 years 475 0.56 ' Notes: 1. Based on a soft rock site, SB/C, and soil amplification factor of 1.0 for Soil Profile Type Sp. ' 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. IEARTH SYSTEMS SOUTHWEST June 12, 2006, 8 File No.: 10655-01 06-06-767 2001 CBC Seismic Coefficients for Chapter 16 Seismic Provisions x 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: A Table 16-U Closest Distance to Known Seismic Source: 8.7 km = 5.4 miles (San Andreas fault) Near Source Factor, Na: 1.05 Table 16-5 Near Source Factor, Nv: 1.31 Table 16-T Seismic Coefficient, Ca: 0.46 = 0.44Na Table 16-Q Seismic Coefficient, Cv: 0.84 = 0.64Nv Table 16-R Seismic Hazard Zones: The site lies within a moderate liquefaction hazard area established by the 2002 Riverside County General Plan, based on historic high groundwater form 50 to 100 feet and very susceptible (Holocene) sediments. Quantitative liquefaction analyses are typically not required for general construction where groundwater depth exceeds 50 feet. The potential for liquefaction to occur at this site is negligible because the existing depth of groundwater beneath the site exceeds 50 feet and is not expected to return to levels above 50 feet. C. EARTH SYSTEMS SOUTHWEST June 12, 2006 9 File No.: 10655-01 ' 06-06-767 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 Mitieation: ■ ➢ 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 Andreag 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 Sp, and is about 8.7 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. ➢ Ground subsidence from seismic events or hydroconsolidation is a potential hazard in the Coachella Valley area. 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 measuresto 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. ➢ The upper soils were found to be relatively loose to medium dense and are unsuitable in ' their present condition to support structures, fill, and hardscape. The soils within the building and structural areas will require moisture conditioning, over -excavation, and ' recompaction to improve bearing capacity and reduce the potential for differential settlement from static loading. Soils can be readily cut by normal grading equipment. I EARTH SYSTEMS SOUTHWEST June 12, 2006 10 File No.: 10655-01 1 06-06-767 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, existing vegetation, trees, large roots, pavements, foundations, non -engineered fill, construction debris, trash, 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. Siteadin should be in strict tn' g compliance "with the requirements of the South Coast Air Quality Management District ' (SCAQMD). Building Pad Preparation: Because of the split level and proposed grading, soils within the ' building pad and foundation areas should -be over -excavated as follows. ➢ Fill Areas ' The areas to receive structural fill should be initially prepared by removing organic growth from the pad surface and other existing improvements. These areas should then be moisture ' conditioned by the use of sprinklers or rain birds to a depth of 4 to 5 feet below existing grade. The surface should be thoroughly rolled with loaded scrapers to achieve at least 90% of maximum dry density in the upper 3 feet of original grade. The depth of moisture ' penetration and compactive effort should be verified by testing. If moisture penetration and compaction cannot be obtained, over -excavation and compaction will be required. ➢ Cut Areas Areas of cut should be thoroughly watered after the proposed cuts are made to obtain the ' optimum moisture content to a depth of 4 to 5 feet below finish grade. The resulting finish grade surface should be rolled with loaded scrapers to achieve at least 90% of maximum dry density in the upper 4 feet of finish grade. If the minimum recommended density cannot be ' obtained from the surface, over -excavation and recompaction will be required. It is also possible that in areas' of deeper cuts, adequate compaction exists and only pre -moisture ' conditioning is necessary. This should be determined in the field at the time of grading. The depth of moisture penetration and compactive effort should be verified by testing. ' Auxiliary Structures Subgrade Preparation: Auxiliary structures such as garden or retaining walls should have the foundation subgrade prepared similar to the building pad recommendations EARTH SYSTEMS SOUTHWEST 1 1 1 n June 12, 2006 11 File No.: 10655-01 06-06-767 given above. The lateral extent of the over -excavation needs to extend only 2 feet beyond the face of the footing. 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. Shrinkage: The shrinkage factor for earthwork is expected to range from 20 to 30 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 range from 0.1 to 0.2 feet. 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: conformance with Backfill of utilities within roads or public right-of-ways should be placed in the requirements of the governing agency (water district, public works EARTH SYSTEMS SOUTHWEST June 12, 2006 12 File No.: 10655-01 ' 06-06-767 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, pefmanent 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. 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 belowg rade: 1,500 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: 2,000 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. I EARTH SYSTEMS SOUTHWEST June 12, 2006 13 File No.: 10655-01 ' 1 06-06-767 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 '/z 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 ('/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. ' 5.5 Slabs -on -Grade Sub 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 Thick ess and -Reinforcement._ ',Slab thickness and reinforcement of slabs -on -grade- are ' contingent;_on-the_recommendations_ofthe -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 ccan be used iri -concrete slab design for -the expected ' very low 'expansion subgrade-.--- Concrete ubgrade:---Concrete slabs and flatwork should -be -a-minimum, of.4 inches -thick -(actual; not nominal)—We--1 t su_ggest`that� the concrete slabs -be -reinforced -at slab—mid=height-to resist -cracking Concrete floor-' slabs -may , either- -be monolithically placed.- with the-foundations�or`doweled after -footing_ _ ' EARTH SYSTEMS SOUTHWEST 1 1 June 12, 2006 14 File No.: 10655-01 06-06-767 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 (1/4 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 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 cRetaining 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. JLateral Pressures and Sliding Resistance' - Granular Backfill ,,Passive Pressure a 375 pcf - level ground Active Pressure (cantilever walls)35 pcf -level ground ✓ Use when wall is permitted to rotate 0.1% of wall height !At -Rest Pressure._ restrained walls 55pcf - level ground (Dynamic Lateral Earth Pressure 2 Acting at 0.6H, where H is height of backfill in feet 50 pcf Bas_e,Lateral Sliding Resistance - D d 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 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 ' EARTH SYSTEMS SOUTHWEST 1 June 12, 2006 15 File No.: 10655-01 06-06-767 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. 5.7 Mitigation of Soil Corrosivity on Concrete ' Selected chemical analyses for corrosivehwere conducted on soil samples from the project site as shown in Appendix B. The native soils were found to have a low sulfate ion concentration t(100 ppm) and a low chloride ion concentration (409 ppm). 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 very 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 ' 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 I EARTH SYSTEMS SOUTHWEST June 12, 2006 16 File No.: 10655-01 ' 06-06-767 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. ' 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. ' 5.9 Pavements Since no traffic loading was provided by the design engineer or owner, we have assumed traffic ' loading for comparative evaluation. The design engineer or owner should decide the appropriate traffic conditions for the pavements. Maintenance of proper drainage is advised to prolong the service life of the pavements. Water should not pond on or near paved areas. The following ' table provides our preliminary recommendations for pavement sections. Final pavement sections recommendations should be based on design traffic indices and R -value tests conducted during grading after actual subgrade soils are exposed. I EARTH SYSTEMS SOUTHWEST 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: Sp Table 16-J ' Seismic Source Type: A Table 16-U Closest Distance to Known Seismic Source: 8.7 km = 5.4 miles (San Andreas fault) Near Source Factor, Na: 1.05 Table 16-5 ' Near Source Factor, Nv: 1.31 Table 16-T Seismic Coefficient, Ca: 0.46 = 0.44Na Table 16-Q ' Seismic Coefficient, Cv: 0.84 = 0.64Nv Table 16-R 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. ' 5.9 Pavements Since no traffic loading was provided by the design engineer or owner, we have assumed traffic ' loading for comparative evaluation. The design engineer or owner should decide the appropriate traffic conditions for the pavements. Maintenance of proper drainage is advised to prolong the service life of the pavements. Water should not pond on or near paved areas. The following ' table provides our preliminary recommendations for pavement sections. Final pavement sections recommendations should be based on design traffic indices and R -value tests conducted during grading after actual subgrade soils are exposed. I EARTH SYSTEMS SOUTHWEST June 12, 2006 17 File No.: 10655-01 ' 06-06-767 PRELIMINARY RECOMMENDED PAVEMENTS SECTIONS R -Value Subgrade Soils — 50 (assumed) Design Method — CALTRANS 1995 ' Notes: 1. Asphaltic concrete should be Caltrans, Type B, 'h -in. or 3/4 -in. maximum -medium grading and compacted to a minimum of 95% of the 75 -blow Marshall density (ASTM D 1559) or equivalent. 2. Aggregate base should be Caltrans Class 2 (3/4 in. maximum) and compacted to a minimum of 95% of ASTM D1557 maximum dry density near its optimum moisture. 3. All pavements should be placed on 12 inches of moisture -conditioned subgrade, compacted to a minimum of 90% ' of ASTM D 1557 maximum dry density near its optimum moisture. 4. Portland cement concrete should have a minimum of 3250 psi compressive strength at 28 days. 5. Equivalent Standard Specifications for Public Works Construction (Greenbook) may be used instead of Caltrans specifications for asphaltic concrete and aggregate base. ' EARTH SYSTEMS SOUTHWEST Flexible Pavements Rigid Pavements Asphaltic Aggregate Portland Aggregate Traffic Pavement Use Concrete Base Cement Base Index Thickness Thickness Concrete Thickness (Assumed) (Inches) I (Inches) I (Inches) (Inches) 4.5 Auto Parking Areas 3.0 4.0 4.0 4.0 7.0 Heavy Traffic 4.0 8.0 5.0 4.0 ' Notes: 1. Asphaltic concrete should be Caltrans, Type B, 'h -in. or 3/4 -in. maximum -medium grading and compacted to a minimum of 95% of the 75 -blow Marshall density (ASTM D 1559) or equivalent. 2. Aggregate base should be Caltrans Class 2 (3/4 in. maximum) and compacted to a minimum of 95% of ASTM D1557 maximum dry density near its optimum moisture. 3. All pavements should be placed on 12 inches of moisture -conditioned subgrade, compacted to a minimum of 90% ' of ASTM D 1557 maximum dry density near its optimum moisture. 4. Portland cement concrete should have a minimum of 3250 psi compressive strength at 28 days. 5. Equivalent Standard Specifications for Public Works Construction (Greenbook) may be used instead of Caltrans specifications for asphaltic concrete and aggregate base. ' EARTH SYSTEMS SOUTHWEST 1 June 12, 2006 18 File No.: 10655-01 06-06-767 Section 6 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 P g 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. LAS_ W� uld`bCprovided the`opportunity four a.general.review.of.final.design and specifications ' i'n oorder`that-earthworkand_foundation_recommendations-may be'properly interpreted 'and implemented=in the rid specifications. 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 an investigation for the presence or absence of wetlands, hazardous ' EARTH SYSTEMS SOUTHWEST June 12, 2006 19 File No.: 10655-01 ' 06-06-767 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. T-he=geotechnical.--engineering j rmrm providing, tests - and observdtio s shall_ _ assumethe ' responsibility of GeotechnicaLEngineer-of_Recoid. 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 -14 our office. The recommended review, tests, and observations include, but are not necessarily limited to, the following: • tConsultation during the final, design -stages of the project. ' A,,r-eview of the building and gradiiig'plans to observe that recommendations _of our repoft7 have been properly -implemented into the design. • Observation and testing-durin site preparation, grading, and placement of engineered neered fll �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. 1 11 EARTH SYSTEMS SOUTHWEST June 12, 2006 20 File No.: 10655-01 06-06-767 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. I American Society of Civil Engineers (ASCE), 2003, Minimum Design Loads for Buildings and Other Structures, ASCE 7-02 ' California Department of Water Resources, 1964, Coachella Valley Investigation, Bulletin No. 108, 146 pp. I 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. ' Envicom Corporation and the County of Riverside Planning Department, 1976, Seismic Safety and Safety General Plan Elements Technical Report, County of Riverside. 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. I 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. 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, 2002, Geotechnical Element of the Riverside County General Plan — Hearing Draft. ' EARTH SYSTEMS SOUTHWEST June 12, 2006 21 File No.: 10655-01 06-06-767 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. EARTH SYSTEMS SOUTHWEST r EARTH SYSTEMS SOUTHWEST t O 'Figure APPENDIX A 1 — Site Location Map p Figure 2 — Boring Location Map ' Table 1 — Fault Parameters Terms and Symbols used on Boring Logs Soil Classification System Logs of Borings • � j r EARTH SYSTEMS SOUTHWEST t O 116°18'0"W. 0 565000 0 Z� N M 1 r - r•., M 0 M 0 0 0 M M Z 0 M 2 or C C 'a C, C ll6°17'15"W 566000 116016'30"W 116°15'45"W 567000 568000 569000 565000 566000 567000 568000 569000 116°18'0"W 116°17'15"W 116016'30"W 116°15'45"W 0 500 1,000 2,000 3,000 4,000 5,000 Feet N Figure 1 Site Location Map LEGEND SWC Dune Palms Road & Highway 11-1 La Quinta, Riverside County, California Site Boundary` Earth Systems 00*1— Southwest 06/12/06 1 File No.: 10655=01 n 7 v M M t� AVENUE i We 1i — + + �, i -+ _f , u"u Il . a der i AyFrvz,F Well a i 1i• jj I Point 1I } s� 6 Happy fi.i 1, y4r 4� a y� y Bit '-L) } a' AVENUE __ ...i s - P R t 6 1 �j.�`a'f K61 72 ••!d 1. TIP b!'K SITE ' a11W F'ark , -.. rR4ef ytar'p ., ••g N 565000 566000 567000 568000 569000 116°18'0"W 116°17'15"W 116016'30"W 116°15'45"W 0 500 1,000 2,000 3,000 4,000 5,000 Feet N Figure 1 Site Location Map LEGEND SWC Dune Palms Road & Highway 11-1 La Quinta, Riverside County, California Site Boundary` Earth Systems 00*1— Southwest 06/12/06 1 File No.: 10655=01 n 7 v M M t� AVENUE i We 1i — + + �, i -+ , i AyFrvz,F `. wel9 a 1i• jj 565000 566000 567000 568000 569000 116°18'0"W 116°17'15"W 116016'30"W 116°15'45"W 0 500 1,000 2,000 3,000 4,000 5,000 Feet N Figure 1 Site Location Map LEGEND SWC Dune Palms Road & Highway 11-1 La Quinta, Riverside County, California Site Boundary` Earth Systems 00*1— Southwest 06/12/06 1 File No.: 10655=01 n 7 v M M 7 116°x6'4 2" G6 F;S ir.'. C6OE) 567000 .: 566900 11(','6'42"W 0 40 80 11 6C 240 320 40C =Few LEGEND N Figure 2 Boring Location Map Boring Location SWC Dune Palms Road & Highway 111 Site Flan La Quinta, Riverside County, California p■.m..me � Earth Systems Site Boundary Southwest 06/12x06 I File No.: 10655-01 t 1 1 1 1 Southwest Corner of Dune Palms Road and Highway 111 10655-01 Table 1 Fault Parameters & Deterministic Estimates of Mean Peak C:rnnnrl Acceleration (PGAI 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 PGA (g) Reference Notes: 1 2 3 4 2 2 2 5 San Andreas - Southern 5.4 8.7 SS A 7.7 24 220 199 0.45 San Andreas - Banning Branch 5.7 9.2 SS A 7.2 10 220 98 0.37 San Andreas - Mission Crk. Branch 5.7 9.2 SS A 7.2 25 220 95 0.37 Blue Cut 14.1 22.6 SS C 6.8 1 760 30 0.17 San Jacinto (Hot Spgs - Buck Ridge) 17.2 27.7 SS C 6.5 2 354 70 0.12 Burnt Mtn. 17.4 28.1 SS B 6.5 0.6 5000 21 0.12 Eureka Peak 18.3 29.5 SS B 6.4 0.6 5000 19 0.11 San Jacinto-Anza 21.5 34.7 SS A 7.2 12 250 91 0.14 San Jacinto -Coyote Creek 21.9 35.2 SS B 6.8 4 175 41 0.11 Morongo 28.8 46.4 SS C 6.5 0.6 1170 23 0.07 Pinto Mountain 30.3 48.8 SS B 7.2 2.5 499 74 0.11 Emerson So. - Copper Mtn. 31.6 50.9 SS B 7.0 0.6 5000 54 0.09 Landers 32.5 52.3 SS B 7.3 0.6 5000 83 0.10 Pisgah -Bullion Mtn. -Mesquite Lk 33.6 54.1 SS B 7.3 0.6 5000 89 0.10 San Jacinto - Borrego 35.3 56.8 SS B 6.6 4 175 29 0.06 San Jacinto -San Jacinto Valley 36.8 59.2 SS B 6.9 12 83 43 0.07 North Frontal Fault Zone (East) 38.7 62.3 RV B 6.7 0.5 1727 27 0.08 Earthquake Valley 40.2 64.7 SS B 6.5 2 351 20 0.05 Brawley Seismic Zone 41.2 66.3 SS B 6.4 25 24 42 0.05 Johnson Valley (Northern) 43.3 69.7 SS B 6.7 0.6 5000 35 0.06 Elsinore -Julian. 44.3 71.3 SS A 7.1 5 340 76 0.07 Calico - Hidalgo 45.0 72.4 SS B 7.3 0.6 5000 95 0.08 Elsinore -Temecula ^` 48.0 77.3 SS B 6.8 5 240 43 0.05 Lenwood-Lockhart-Old Woman Sprgs 49.1 79.1 SS B 7.5 0.6 5000 145 0.08 Elmore Ranch 49.3 79.4 SS B 6.6 1 225 29 0.05 North Frontal Fault Zone (West) 49.8 80.2 RV B 7.2 1 1314 50 0.08 Elsinore -Coyote Mountain 51.4 82.7 SS B 6.8 4 625 39 0.05 Superstition Mtn. (San Jacinto) 53.4 85.9 SS B 6.6 5 500 24 0.04 Superstition Hills (San Jacinto) 54.2 87.2 SS B 6.6 4 250 23 0.04 Helendale - S. Lockhardt 57.0 91.8 SS B 7.3 0.6 5000 97 0.06 San Jacinto -San Bernardino 59.0 95.0 SS B 6.7 12 100 36 0.04 Elsinore -Glen Ivy 61.6 99.2 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: 33.706 N Latitude, 116.278 W Longtude and Site Soil Type D EARTH SYSTEMS SOUTHWEST 11 1 fl 11 11 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 12" 3" 3/4" 4 10 40 200 GRAVEL I SAND BOULDERS COBBLES COARSE I FINE COARSE MEDIUM FINE SILT CLAY 3Ub 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). 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 Water Level (measured or after drilling) Terms and Symbols used on Boring Log Water Level (during drilling) 2 � MAJOR DIVISIONS CLEAN GRAPHIC LETTERSYMBOL SYMBOL GW TYPICAL DESCRIPTIONS Well -graded gravels, gravel -sand mixtures, little or no fines ' GRAVELS < 5% FINES GRAVEL AND GRAVELLY SOILS ,•�• .�•�•�•�•�•� �i ra ri ri !i ri ra ri•, �.•r..r,.r,.�•.r•.r,.r•. + ......•..•..•.+•.+•. ir• r• r• r• r• r• r• r• ■ •■ •• + •+ •■ ■ r� r� �. �. •r: �� r..' GP Poorly -graded gravels, gravel -sand mixtures. Little or no fines ' ' COARSE More than 50% of GRAVELS WITH FINES coarse fraction GRAINED SOILS retained on No. 4 > 12% FINES sieve ; :;;:� ; GM GC Silty gravels, gravel -sand -silt mixtures Clayey gravels, gravel -sand -clay mixtures ' SAND AND CLEAN SAND SANDY SOILS (Little or no fines) < 5% More than 50% of material is laroer SW Well -graded sands, gravelly sands, little or no fines :: °T°' ° :::i>::::•::•:;•::: . ' '` ` - ...� ... •::::: ; SP Poorly -graded sands, gravelly sands little or no fines SM Silty sands, sand -silt mixtures ' than No. 200 sieve sizeSAND WITH FINE 'passing More than 50% of (appreciable coarse fraction amount of fines) No. 4 sieve >12% SC Clayey sands, sand -clay mixtures ML Inorganic silts and very fine sands, rock flour, silty low clayey fine sands ... or clayey silts with slight plasticity ' LIQUID LIMIT FINE-GRAINED LESS THAN 50 SOILS - - - - - - - --------- - ----- - CL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays SILTS AND "F Ii r i 11 -! ! �� r,,, i r i i ' ! ! ' ' ! ' ! OL Organic silts and organic silty clays of low plasticity Y P Y CLAYS Inorganic silty, micaceous, or MH diatomaceous fine sand or silty soils 50% or more of ' material is smaller LIQUID LIMIT than No. 200 GREATER sieve size THAN 50 CH Inorganic clays of high plasticity, fat clays ' HIGHLY ORGANIC SOILS VARIOUS SOILS AND MAN MADE MATERIALS ............. r rnr r�'y yy� yyy ry y y yyy OH PT Organic clays of medium to high plasticity, organic silts Peat, humus, swamp soils with high organic contents Fill Materials ' MAN MADE MATERIALS Asphalt and concrete ' Soil Classification System Earth Systems -- Southwest ' 0Earth -Systems Southwest 79-811 B Country Club Drive, Bermuda Dunes, CA 92203 Phone (760)345-1588•Fax (760)345-7315 1 1 1 1 1 1 1 1 1 1' 1 1 1 1 1 1 1 1 BorinNO: B-1 I Drilling Date: May 22, 2006 Project ame: SWC Dune Palms Road & Highway 111, La Quinta, CA Drilling Method: 8" Hollow Stem Auger File Number: 10655-01 Drill Type: Williams CME 55 w/Auto Hammer Boring Location: See Figure -2 Logged By: Jason Stormo w Sample Type Penetration _ o Description of Units Page 1 of 1 w.i au w Resistance O E Cn U �-• A a i .+ .o Note: The stratification lines shown represent the A Y p 75 (Blows/6") v��, A A " c j approximate boundary between soil and/or rock types Graphic Trend M N � and the transition may be gradational. Blow Count Dry Density SM SILTY SAND: light yellow brown, dry, fine to T. medium grained 5 SILTY SAND: No Recovery 1 st attempt; redril led 4,6,7 SM 95 I within 8 feet; 2nd attempt medium dense, dry, fine grained 10 SP -SM SAND WITH SILT: light yellow brown with gold 6,11,13 103 1 fleck, medium dense, dry, very fine grained 15 SM/ML SILTY SAND TO SANDY SILT: light yellow 3,7,10 89 4 brown, medium dense, dry, very fine grained Total Depth 16.5 feet 20 No Groundwater Encountered 25 30 35 r an 1-0 Earth Systems , 1 Southwest 79-811 B Country Club Drive, Bermuda Dunes, CA 92203 Phnne(76011d5-15RR FAY(76m11di-7115 I 1 1 1 1 1 1 1 BorIn B-2 Drilling Date: May 22, 2006 Project ame: SWC Dune Palms Road & Highway 111; La Quinta, CA Drilling Method: 8" Hollow Stem Auger File Number: 10655-01 Drill Type: Williams CME 55 w/Auto Hammer Boring Location: See Figure 2 Logged By: Jason Stormo v Sample Type w Penetration o C �' Description of Units Page 1 of 1 n Resistance E �� q •o Note: The stratification lines shown represent the q y p (Blows/6") rn q o approximate boundary between soil and/or rock types Graphic Trend q V and the transition may be gradational. Blow Count Dry Density SM SILTY SAND: light yellow brown, medium dense, dry, fine to medium grained 6,12,13 108 1 5 2 6 8 94 1 SP -SM SAND WITH SILT/SILTY SAND: light yellow brown with gold fleck, medium dense, dry, very fine 10 grained 6,9,14 94 1 ML SANDY SILT/SILT WITH SAND: light yellow brown, medium dense, dry, very fine grained 15 5,9,14 90 3 20 Total Depth 19 feet No Groundwater Encountered 25 30 35 nn 0' Earth Systems Southwest 79-8118 Country Club Drive, Bermuda Dunes, CA 92203 Phone (760) 345-1588. Fax (760) 345-7315 1 1 fl 1 BorinNo: B-3 Drilling Date: May 23, 2006 Projec&ame: SWC Dune Palms Road & Highway 11 I, La Quinta, CA Drilling Method: 8" Hollow Stem Auger File Number: 10655-01 Drill Type: Williams CME 55 w/Auto Hammer Boring Location: See Figure 2 Logged By: Jason Stormo v Sample Type w Penetration _ 1 Description of Units Page 1 of I n Resistance °Note: E A Q o 2 The stratification lines shown represent the p o 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 SP -SM SAND WITH SILT/SILTY SAND: light yellow brown, dense, dry, fine grained 5 7,14,21 106 1 10 SM SILTY SAND: light yellow brown, medium dense, 4 7 11 97 6 dry, fine grained 15 3,7,11 98 1 20 5,11,16 94 1 Total Depth 21.5 feet 25 No Groundwater Encountered 30 35 AA Earth Systems 1� southwest 79-811B Country Club Drive, Bermuda Dunes, CA 92203 rnone tiou) .sv3-i Baa, rax (iou) sv>-is u Boring No: B4 Drilling Date: May 23, 2006 Project Name: SWC Dune Palms Road & Highway 111, La Quinta, CA Drilling Method: 8" Hollow Stem Auger File Number: 10655-01 Drill Type: Williams CME 55 w/Auto Hammer Boring Location: See Figure 2' Logged By: Jason Stormo v Sample Type Penetration _ 41 °:' Description of Units Page 1 of I a w Resistance U °' q a .o V Note: The stratification lines shown re resent the P p0 (Blows/6") Q C approximate boundary between soil and/or rock types Graphic Trend SM 99 1 �l SILTY SAND: light yellow brown, medium dense, t j and the transition may be gradational. Blow Count Dry Density ,,r -5 - 10 --15 20 25 30 35 40 ML SILT: light yellow brown, firm, dry, fine grained 4,10,18 91 5 I 3,5,9 SM 99 1 �l SILTY SAND: light yellow brown, medium dense, dry, fine grained Total Depth 11.5 feet No Groundwater Encountered a APPENDIX B Laboratory Test Results 1 ' 1 - -EARTH SYSTEMS SOUTHWEST File No.: 10655-01 June 12, 2006 ' Lab No.: 06-0291 UNIT DENSITIES AND MOISTURE CONTENT ASTM D2937 & D2216 ' Job Name: SWC Dune Palms &Hwy 111, LQ, CA t { r 1 . 1 1' Unit Moisture USCS Sample Depth Dry Content Group Location (feet) Density (pcf) (%) Symbol BI 5 95 1 SM BI 10 103 1 SP -SM B1 15 89 4 SM/ML B2 2.5 108 1 SM B2 7.5 94 1 SP -SM B2 12.5 94 1 ML B2 17.5 90 3 ML B3 5 106 1 SP -SM B3 10 97 6 SM B3 15 98 1 SM B3 20 94 1 SM B4 5 91 5 ML B4 10 99 1 SM EARTH SYSTEMS SOUTHWEST File No.: 10655-01 June 12, 2006 Job Name: SWC Dune Palms & Hwy 111, LQ, CA Lab Number: 06-0291 AMOUNT PASSING NO. 200 SIEVE ASTM D 1140 131 10 13 Fines USCS Sample Depth Content Group Location (feet) N Symbol 131 10 13 SP -SM B2 12.5 70 ML* B3 5 11 SP -SM B4 5 90 ML * Silt lenses in sample r EARTH SYSTEMS SOUTHWEST File No.: 10655-01 June 12, 2006 Lab No.: 06-0291 . PARTICLE SIZE ANALYSIS ASTM D-422 Job Name: SWC Dune Palms & Hwy 111, LQ, CA Sample ID: B1 @ 1-4 Feet, Description: Brown Silty Fine Sand (SM) Sieve Percent Size Passing 1-1/2" 100 1" 100 3/4" 100 1/2" 100 3/8" 100 #4 100 #8 100 #16 100 % Gravel: 0 #30 99 % Sand: 68 #50 95 % Silt: 27 #100 65 % Clay (3 micron): 5 #200 32 (Clay content by short hydrometer method) 100 j 90 80 ` 70- 1- I I { I I 60 c 50 i 1-�- ---- - --- - - -I-- -- -- —I --I L 30 - — — - 20 10 0 ! I I 100 .10 l 0.1 0.01 0.001 Particle Size ( mm) EARTH SYSTEMS SOUTHWEST File No.: 10655-01 June 12, 2006 Lab No.: 06-0291 MAXIMUM DENSITY / OPTIMUM MOISTURE ASTM D 1557-91 (Modified) Job Name: SWC Dune Palms & Hwy 111, LQ CA Procedure Used: A Sample ID: 1 Preparation Method: Moist Location: B1 @ 1-4 Feet Rammer Type: Mechanical Description: Brown Silty Fine Sand (SM) Lab Numbe: 06-0291 Sieve Size %Retained Maximum Density: 110.5 pcf 3/411 0.0 Optimum Moisture: 14.5% 3/8" 0.0 #4 0.0 140 135 130 125 110 105 100. 0 5 10f 15 20 25 Moisture Content, percent EARTH SYSTEMS SOUTHWEST 30 35 LN 0i=1 0 Eli ----- Zero Air Voids Lines sg =2.65, 2,70 2 75 C1 0 no "EN11011014 MM No IN 0 M "I INN Elm MEN ME IN NMI INN 0 MEN 'L\i0,1011 M No MENNEN- Mri.rar., MMM`MM E ME No qLN"'%j=P.1 Elm= ml 0 NNI I 5 10f 15 20 25 Moisture Content, percent EARTH SYSTEMS SOUTHWEST 30 35 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 M File No.: 10655-01 June 12, 2006 Lab No.: 06-0291 Amount in Soil SOIL CHEMICAL ANALYSES Soluble 0 -1000 mg/Kg (ppm) [ 0-.1%] Low Job Name: SWC Dune Palms & Hwy 111, LQ, CA 1000--2000 mg/Kg (ppm) [0.1-0.2%] Job No.: 10655-01 Sample ID: B1 Severe Sample Depth, feet: 1-4' DF RL Sulfate, mg/Kg (ppm): 100 1 0.50 Chloride, mg/Kg (ppm): 409 1 0.20 pH, (pH Units): 7.85 1 0.41 Resistivity, (ohm -cm): 650 N/A N/A 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 m (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