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Earth Systems
1FO Southwest 79-811B Country Club Drive
Bermuda Dunes, CA 92201
(760)345-1588
(800)924-7015
FAX (760) 345-7315
April 11, 2001 File No.: 08119-01
' 01-04-716
Mc Dermott Enterprises
' P.O. Box 163
Palm Desert, California
' Attention: Mr. Colin McDermott
Project: Proposed Commercial Development
' La Quinta, California
Subject: GEOTECHNICAL ENGINEERING REPORT
' Dear Mr. McDermott:
' We take pleasure to present this Geotechnical Engineering Report prepared for the proposed
commercial development to be located'on the southeast corner of Washington Street and Avenue
47 in the City of La Quinta, California:
_ . This report presents our findings and recommendations for 'site grading and foundation design,
incorporating the information supplied to our office. The site is suitable for the proposed
devel` mment. The recommendations in this report should be incorpora Hein o eproposed
design and construction. This report should stand as a whole, and no part of the report should be
excerpted or used to the exclusion of any other part.
' This report completes our scope of services in accordance with our-agreement, dated March 5,
2001 and authorized on March 7, 2001 Other services that may be required, such as. plan review
and grading observation, are additional services and will be billed according to the Fee Schedule
' in effect at the time services are provided: Unless requested in writing, the client is responsible
to distribute this report to the appropriate governing agency or other members of the design team.
' We appreciate the opportunity to provide our professional services. Please contact our office if
there are any questions or comments concerning this report or its recommendations.
Respectfully 9o0
tEARTH S WEST
CE 38234 m y-
Craig S. EXP. Z/31/05 m
CE 3823
sT9T CML
' SER/kah/cs of C of
Distribution: 6/1\4cDermott Enterprises
INTA File
2/BD File
TABLE OF CONTENTS '
Page
Section 1 INTRODUCTION.........:.............:..............:.....................................................:.....1
1.1 Project Description.................................................:................................:................1
1.2 Site Description ................ **"**.............. :........................ :.......................................... 1
1.3 Purpose and Scope of Work ....................... :................ ...,.......... :............................2
Section 2
METHODS OF INVESTIGATION..................r...........................:......................3
2:1
Field Exploration........::............::...........:...:..........:..::..................:...........................3
2.2
Laboratory Testing.....:...........................................:.:.:...........::..........................:.....3
Section 3
DISCUSSION ................................................. ...::......::...........................................4
3.1
Soil Conditions ......:...:..:.:.:. ....4
3.2
Groundwater ............................................. ...............................................................
4
3.3
Geologic Setting: ........4
3.4
Geologic Hazards.......::.........::.......:......................................:..................................5
3.4.1 Seismic Hazards.::..............................:........................................................5
3.4.2 Secondary Hazards.:....................:....:.........:.................:...............................6
3.4.3. Site Acceleration and Seismic Coefficients..:.......:..:...................................7
Section 4
CONCLUSIONS `....................
Section 5
RECOMMENDATIONS ....................................... .................. :...........................
10
SITE
DEVELOPMENT AND GRADING..:. ... ...
10
5.1
Site Development —Grading ........ ...::............ :....... .:.....::.:..............................10
5.2
Excavations and Utility Trenches —, ..............11
5.3
Slope Stability of Graded Slopes............::.`....:......:..;.:.....:.:.::...:................:..........11
STRUCTURES..................::...............................:..............................::............................12
5.4
Foundations...............:.:.....:...:..........................:.:..................................................12
.
5.5
Slabs -on -Grade ......................:
5.6
Retaining Walls.........:.....::.......::...:.....:.::...........:..:.:...:..:.......:...............................14
5.7
Mitigation of Soil Corrosivity on Concrete ............ ................:...... .15
....................
5.8
.Seismic Design Criteria.::..................:......:.........:................:..............:.................15
5.9
Pavements ...................................... .........................................................................
16
Section 6
LIMITATIONS AND ADDITIONAL SERVICES..........................................17
6.1
Uniformity of Conditions and Limitations ............................. :...............................
17
6.2
Additional Services'....:.....;.......:
18
REFERENCES................:..........................................:..........................................19
APPENDIX A
Site Location Map
Boring Location Map
Table 1 Fault Parameters
2000 International Building Code (IBC) Seismic Parameters
Logs of Borings
APPENDIX B :
Laboratory Test Results
April 11, 2001 -1 File No.: 08119-01
01-04-716
Section 1
INTRODUCTION
' 1.1 , Project Description
P
' This Geotechnical Engineering Report has been prepared for the proposed commercial
development to be located between Washington Street and Caleo Bay, and south of Avenue 47 in
the City of La Quinta, California.
The proposed new buildings will consist of one and two-story structures. We understand that the
proposed structures will be of wood frame and stucco construction and will be supported by
conventional shallow continuous or pa oo mgs. rte evelopment will include. site grading,
building pad preparation, underground utility installation, street and parking lot construction, and
concrete driveway and sidewalk placement. Based on existing site topography, site grading is
expected to consist of fills not exceeding approximately 5 -feet.
We used maximum column loads of 50 kips and a maximum, wall loading of 2.5 kips per linear
foot as a basis for the foundation recommendations. All loading is assumed to be dead plus
actual live load. The preliminary design loading was assumed based on our understanding of the
construction type and number of supported floors. If actual structural loading exceeds these
assumed values, we would need to reevaluate the given recommendations.
1.2 Site Description
The proposed commercial development is to be constructed on the irregular shaped parcel as
shown on Figures 1 and 2 in Appendix A. The site is currently vacant of structures. Evidence of
past development of the site is apparent. Miscellaneouscons ruc ionensis present throughout
the site. A closed depression (approximately 5 feet in depth) of unknown origin is located near
the southwest corner of the site and is within the footprint of the proposed 4000-ft2 office
building. A buried concrete slab was encountered while drilling in the southeast portion of the
site (see Boring B-1). A review of historic aerial photos shows that past development of the site
was apparently concentrated in the southern portion of the site.
The site is relatively flat with minor surface variations of 1 to 3 feet, except in the area of the
closed depression that was approximately 5 feet in depth. A sparse to moderate growth of weeds
and brush including some trees cover the site. The site. is generally bounded by 47`h Avenue to
the north, to the east by Caleo Bay, to the south by vacant land and to the west by Washington
Street. The elevation of the site is approximately 60 feet above mean sea level.
Underground utilities are believed to exist along the site boundaries and may encroach within the
proposed areas for building and development. Presumably, abandoned on-site underground
utilities associated with past development .are also assumed to exist on the site. These utility
lines may include, but are not limited to, domestic water, telephone, electrical, sewer/septic
(including septic tank, leach lines and/or seepage pit or cesspool) and irrigation lines.
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' April 11, 2001 - 2 - File No.: 08119-01
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a of Work .3 Pur ose and Scope 1 P P
' The purpose for our services was1to 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 5 exploratory borings to depths ranging from
' 29 to 51.5 feet.
➢ Laboratory testing of selected soil samples obtained from the exploratory borings.
➢ Review of.selected published technical literature pertaining to the site.
' ➢ Engineering analysis and evaluation of the acquired data. from the, exploration and testing
programs.
➢ A summary of our findings and recommendations in this written report.
' This report contains the following:
g
➢ 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.
Not Contained In This Report: Although available through Earth Systems Southwest, the current
scope of our services does not include:
➢ A corrosive study to determine cathodic protection of concrete or buried pipes.
' ➢ An environmental assessment.
➢ Investigation for the presence or absence of wetlands, hazardous or toxic materials in the
soil, surface water, groundwater, or air on, below, or adjacent to the subject property.
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' April 11, 2001 -3 - File No.: 08119-01
01-04-716
Section 2
METHODS OF INVESTIGATION
' 2.1 Field Exploration
' Five exploratory borings were drilled to depths ranging from 29 to 51.5 feet below the existing
ground surface to observe the ' soil profile and to obtain samples for laboratory testing. The
borings were drilled on March 8, 2001 using 8 -inch outside diameter hollow -stem augers, and
' powered by a Mobile B61 truck -mounted drilling rig. The boring locations are shown on the
boring location map, Figure 2, in Appendix A. The locations shown are approximate,
established by pacing and sighting from existing topographic features.
' Samples were obtained within the test borings using a Standard Penetration (SPT) sampler
(ASTM D 1586) and a Modified California (MC) ring sampler (ASTM D 3550 with shoe similar
' to ASTM D 1586). The SPT sampler has a 2 -inch outside diameter and a 1.38 -inch inside
diameter. The MC sampler has a 3 -inch outside diameter and a 2.37 -inch inside diameter. The
samples were obtained by driving the sampler with a 140 -pound automatic hammer dropping
' 30 inches in general accordance with ASTM D 1586. Recovered soil samples were sealed in
containers and returned to the laboratory. Bulk samples were also obtained from auger cuttings,
representing a mixture of soils encountered at the depths noted.
' The final logs of the borings represent our interpretation of the contents of the field logs and the
results of laboratory testing performed on the samples obtained during the subsurface
investigation. The final logs are included in Appendix A of this report. The stratification lines
represent the approximate boundaries between soil types although the transitions 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 structures. Test results are
' presented in graphic and tabular form in Appendix B of this report. The tests were conducted in
general accordance with the procedures of the American Society for Testing and Materials
(ASTM) or other standardized methods as referenced below. Our testing program consisted of
the following:
➢ In-situ Moisture Content and Unit Dry Weight for the ring samples (ASTM D 2937).
' ➢ Maximum density tests were performed to evaluate the moisture -density relationship of
typical soils encountered (ASTM D 1557-91).
➢ Particle Size Analysis (ASTM D 422) to classify and evaluate soil composition. The
' gradation characteristics of selected samples were made by hydrometer and sieve analysis
procedures.
Consolidation (Collapse Potential) (ASTM D 2435 and D 5333) to evaluate the
compressibility and hydroconsolidation (collapse) potential of the soil.
Chemical Analyses (Soluble Sulfates & Chlorides, pH, and Electrical Resistivity) to
evaluate the potential adverse effects of the soil on concrete and steel.
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April 11, 2001 - 4 - File No.: 08119-01
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Section 3
DISCUSSION
3.1 Soil Conditions
' The field exploration indicates that site soils consist primarily of medium dense, interbedded
silty Sand, Silt and Sand (Unified Soil Classification Symbols of SM, ML, and SP -SM,
respectively). The boring logs provided in Appendix A include more detailed descriptions of the
' soils encountered. The soils are visually classified to be in the very low expansion category in
accordance with Table 18A -I -B of the Uniform Building Code.
' 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. Consolidation
' tests indicate 2.2 to 3.6% collapse upon inundation and are considered a moderate site risk at
depths of 17.5 feet in Boring 4 and 10 feet in Boring 3, respectively. The hydroconsolidation
potential is commonly mitigated by recompaction of a zone beneath building pads. However,
' due to the depth of the potential hydroconsolidation, removal and recompaction to a depth of 20
feet is ' not economically reasonable. Therefore, alternative foundation recommendations are
offered for your consideration
3.2 Groundwater
' Free groundwater was not encountered in the borings during exploration. The depth to
groundwater in the area is believed to be in excess of 100 feet. Groundwater levels may
fluctuate with .precipitation, irrigation, drainage, regional .pumping from wells, and site grading.
' The absence of groundwater levels detected may not represent an accurate or permanent
condition.
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 from San Gorgonio Pass, approximately 180 miles to the Gulf of California. Much of
' this depression in the area of the Salton. Sea is below sea level.
The Coachella Valley forms the northerly portion of the Salton Trough. The Coachella Valley
contains a thick sequence of sedimentary deposits that are Miocene to recent in age. Mountains
surrounding the Coachella Valley include the Little San Bernardino Mountains on the northeast,
foothills of the San Bernardino Mountains on the northwest, and the San Jacinto and Santa Rosa
Mountains on the southwest. These mountains expose primarily Precambrian metamorphic and
Mesozoic granitic rocks. The San Andreas Fault zone within the Coachella Valley consists of
the Garnet Hill Fault, the Banning Fault, and the Mission Creek Fault that traverse along the
northeast margin of the valley.
Local Geology: The project site lies at an elevation of about 60 -feet above mean sea level in the
lower part of the La Quinta Cove portion of the Coachella Valley. The La Quinta Cove is
situated on an alluvial wedge between two granite mountain spurs of the Santa Rosa Mountains.
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' The waters of ancient Lake Cahuilla once covered thero'ect site. The sediments within the
P J
cove consist of fine to coarse-grained sands with interbedded clays, silts, and gravels of aeolian
' (wind-blown), alluvial (water laid), and lacustrine (lake bed) origin. The site is located near the
boundary between the lacustrine deposits_of ancient Lake Cahuilla, and alluvial deposits from the
Santa Rosa Mountains to the south.
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 groundshaking 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 (CDMG, 1996). 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, 1994). Well -delineated fault lines cross
through this region as shown on California Division of Mines and Geology (CDMG) maps
(Jennings, 1994). 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 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 & 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.
' • Hector Mine Earthquake - On October 16, 1999, a magnitude 7.1MW earthquake occurred on the
Lavic Lake and Bullion Mountain Faults north of 29 Palms. This event while widely felt, no
significant structural damage has been reported in the Coachella Valley.
�_ EARTH SYSTEMS SOUTHWEST
April 11, 2001 - 6 - File No.: 08119-01
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' Seismic Risk: While accurate earthquake predictions are not possible, various agencies have
conducted statistical risk analyses. In 1996, the California Division of Mines and Geology
' (CDMG) and the United States Geological Survey (USGS) completed the latest generation of
probabilistic seismic hazard maps for use in the 1997 UBC. 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 to 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 7.4 for the
Southern Segment of the fault. This segment has the longest elapsed time since rupture than any
' other portion 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 both 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
' deformation, areal subsidence, tsunamis, and seiches. The site is far inland so the hazard from
tsunamis is non-existent. An existing residential development'that includes a man made lake is
located immediately southeast of the 'project site, therefore, hazards from seiches (water
' - sloshing) should be considered a slight site risk.
Soil Liquefaction: Liquefaction is the loss of soil strength from sudden shock (usually
' earthquake shaking), causing the soil to become a fluid mass. In general, for the effects of
liquefaction to be manifested at the surface, groundwater levels must be within 50 feet of the
ground surface and the soils within the saturated zone must also be susceptible to liquefaction.
' The potential for liquefaction to occur at this site is considered negligible because the depth of
groundwater beneath the site exceeds 50 feet.. No free groundwater was encountered in our
exploratory borings. In addition, the project does' not lie within the Riverside County
' liquefaction study zone.
Ground Deformation and Subsidence: Non -tectonic ground deformation consists of cracking of
the ground with little to no displacement. This type of deformation is generally associated with
differential shaking of two or more geologic units with differing engineering characteristics.
Ground deformation may also be caused by liquefaction. As the site is relatively flat with
' consistent geologic material, and has a low potential for liquefaction, the potential for ground
deformation is also considered to be low.
' The potential for seismically induced ground subsidence is considered to be low to moderate at
the site. Dry sands tend to settle and densify when subjected to strong earthquake shaking. e
amount of subsidence is dependent on relative density of the soil, groundshaking (cyclic shear
�- EARTH SYSTEMS SOUTHWEST
April 11, 2001 - 7 - File No.: 08119-01 .
01-04-716
strain), and earthquake duration (number of strain cycles). Uncompacted fill areas may be
susceptible to seismically induced settlement.
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
Site Acceleration: The potential intensity of ground motion may be estimated from 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 also are 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 is an inconsistent scaling factor to compare to the UBC 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. Because of these factors, an effective
peak acceleration (EPA) is used in structural design.
The following table provides the probabilistic estimate of the PGA and EPA taken from the
1996 CDMG/USGS seismic hazard maps.
Estimate of PGA and EPA from 1996 CDMG/USGS
Probabilistic Seismic Hazard Maps
Equivalent Return Approximate
Risk I Period (years) PGA (g) EPA (g) 2
10% exceedance in 50 years 1 475 0.50 0.45
Notes:
1. Based on a soft rock site, SBic.and soil amplification factor of 1.0 for Soil Profile Type SD.
2. Spectral acceleration (SA) at period of 0.3 seconds divided by 2.5 for 5% damping, as defined by
the Structural Engineers Association of California (SEAOC, 1996).
1997 UBC Seismic Coefficients: The Uniform Building Code (UBC) seismic design 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 and EPA estimates given above are
provided for information on the seismic risk inherent in the UBC design. The following lists the
seismic and site coefficients given in Chapter 16 of the 1997 Uniform Building Code (UBC).
EARTH SYSTEMS SOUTHWEST
' April 11, 2001 - 8 File No.: 08119-01
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1997 UBC Seismic Coefficients for Chapter 16 Seismic Provisions
Reference
Seismic Zone: 4 Figure 16-2
Seismic Zone Factor, Z.: OA/ Table 16-I
Soil Profile Type: SD Table 16-J
Seismic Source Type: A Table 16-U
Closest Distance to Known Seismic Source: 9:6 km = 6.0 miles / (San Andreas Fault)
Near Source Factor, Na: 1.Or' Table 16-S
Near Source Factor,Nv: 1.2/ Table 16-T
Seismic Coefficient, Ca:0.45 / = 0.44Na Table 16-Q
Seismic Coefficient, Cv: 0.79 .0.64Nv Table 16-R
Seismic Zoning: The Seismic Safety Element of the 1984 Riverside County General Plan
establishes groundshaking hazard zones. The project area is mapped in Ground Shaking
Zone IEB Ground Shaking Zone are based on distance from causative faults and underlying soil
types. The site does not lie ithin the Liquefaction Hazard area established by this Seismic
Safety Element. These group shaking hazard zones ire used in deciding suitability of land use.
2000 IBC Seismic ' Coefficients: For comparative purposes, . the newly released 2000
International Building Code (IBC) seismic and site coefficients are given in Appendix A. As of
the issuance of this report, we' are unaware when governing jurisdictions may adopt or modify
the IBC provisions.
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' April 11, 200.1 - 9 - " File No.: 08119-01
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Section 4
CONCLUSIONS
The followingis a summary of our conclusions and professional opinions based on the_ data
�' P P
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. The
recommendations in this reportshould e incorporateU incorporateinto 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 Toriginating on the local segment of
the San Andreas Fault zone would be the critical seismic event that mayaffect 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 and about 9.6 km from a Type A seismic source as
defined in the Uniform Building Code. A qualified professional should design any
permanent structure constructed on the site. The minimum seismic design should comply
with the latest edition of the Uniform Building Code.
➢ 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 at least within the upper 5
' feet of finish grade. Due to the potential long-term settlement due to deep saturation of
soils susceptible to hydroconsolidation, special considerations should be given to the
foundation slab -on -grade system. Please refer to the "Foundation" section of this report
' for additional discussion and recommendations.
➢ The soils are susceptible to wind and water erosion. Preventative measures to reduce
' seasonal flooding and erosion should be incorporated into site grading plans. Dust
control should also be implemented during construction. .
' ➢ Other geologic hazards including ground rupture, 'liquefaction, seismically induced
flooding, and landslides are considered low or negligible on.this site.
' ➢ The upper soils were found to be relatively loose to medium dense Silty Sand and Silt
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 settlement from
static loading. Soils can be readily cut by normal grading equipment.
EARTH SYSTEMS SOUTHWEST
' April 11, 2001 _10- File No.: 08119-01
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' . ~ 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 bottom of excavations prior'to placing fill. Local variations in soil conditions may warrant
increasing the depth of recompaction and over -excavation.
' Clearing and Grubbing: Prior to site grading, the existing vegetation, trees, large roots,
pavements, foundations, non -engineered fill, construction debris, trash, abandoned underground
utilities, and other deleterious material should be removed from the proposed building, structural,
' and pavement areas. The. surface should be stripped of organic growth and removed from the
construction area.. Areas disturbed during demolition and clearing .should be properly backfilled
and compacted as.described below.
1 Building Pad Preparation: Because of the relatively non-uniform and under -compacted nature of
the majority of the site soils, we recommend recompaction of soils in the building areas. The
existing surface soils within the building pad and foundation areas should be over -excavated to a
minimum of 48 inches below existing grade or a minimum of 36 inches below the footing level
(whichever is lower). The over -excavation should extend for 5 feet beyond the outer edge of
' exterior footings. The bottom of the sub -excavation should be scarified; moisture conditioned,
and recompacted to at least 90 % relative compaction (ASTM D 1557) for an additional depth of
12 inches. Moisture penetration to near optimum moisture should extend at least 24 inches
' below the bottom of the over=excavation and be verified by testing.
Auxiliary Structures SubQrade Preparation: Auxiliary structures such as garden or retaining
walls should have the foundation subgrade prepared similar to the building pad recommendations
given above. The lateral extent of the over -excavation needs only to extend 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 12 inches below finished subgrades. Compaction should be
verified by testing. Areas subjected to traffic loads .should be prepared in accordance with
Section 5.9, "Pavements."
' 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 sho d be
' placed in maximum 8 -inch lifts (loose) and compacted to at least 90% relative co paction
(ASTM D 1557) near its optimum moisture content. Compaction sfiouic'3'Be ven e'°a y testing.
Imported fill soils (if required) should be non -expansive, granular soils meeting the
USCS classifications of SM, SP -SM, or SW -SM with a maximum rock size of 3 inches and
5 to 35% passing the No. 200 sieve. The geotechnical engineer should evaluate the import fill
soils before hauling to the site. However, because of the potential variations within the borrow
source, import soil will not be pre -qualified by ESSW. The imported fill should be placed in lifts
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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 15 to 20 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. i
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 to vertical) should be provided. No
surcharge loads from stockpiled soils or construction materials should be allowed within a
horizontal distance measured from, the top of the excavation slope, equal to the depth of the
excavation.
Utility Trenches: Backfill of utilities within road or public right-of-ways should be placed in
conformance with the requirements of the governing agency (water district, public works
department, etc.) Utility trench backfill within private property should be placed in conformance
with the provisions of this report.. In general, service lines extending inside of property may be
backfilled with native soils compacted to a minimum of 90% relative compaction. Backfill
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 to 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).
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STRUCTURES
' In our professional opinion, the structure foundation can be supported on shallow foundations
bearing on a zone of properly prepared and compacted soils placed as recommended in
Section 5.1. 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 for
' one-story structures and 15 inches below lowest adjacent grade should be maintained for two-
story structures. A representative of ESSW should observe foundation excavations prior to
placement of reinforcing steel or concrete. Loose soil or construction debris should be removed
' from footing excavations prior to 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 desi� ive loads
Allowable increasesoT750 psf per each foot of additional footing width and 250 psf for each
' . additional 0.5 foot of footing depth may be used up to a maximum value of 2500 psf.
➢ Isolated pad foundations, 2 x 2 foot minimum in plan and 18 inches below grade:
' . X000 psf for dead plus design live loads
Allowable increases of 250psf per each foot of additional footing width and 350 psf for each
additional 0.5 foot of footing depth may be used up to a maximum value of 2500 psf.
A one-third (1/3) increase in the bearing pressure may be used when calculating resistance to
wind or seismic loads. The allowable bearing values indicated are based on the anticipated
' . maximum loads stated in Section 1.1 of this report. If the .anticipated loads exceed these values,
the geotechnical engineer must reevaluate the allowable bearing values and the grading
requirements. .
' Minimum reinfo cement for continuous !wall o footings should be two, e renorcn
g =No4 stifig bars
._ � ,
one pjaced he top and one placed near the bottom of the footing. This reinforcing is not
VON
' intended to supersede any structural requirements provided by the structural engineer.
Grade Beani and Structural Flat Plate Foundation Alternate: An allowable soil bearing pressure
' of 1,500 f may be used in design of an alternate foundation system. A modulus of subgrade
reaction of 200 pci may be used with an expected differential settlement of up to 1 -inch in a
25 -foot span (1/300).
Expected Settlement: Estimated total static settlement, based on footings founded on firm soils
as recommended, should be less than 1 inch. Differential settlement between exterior and
interior bearing members should be less than. 1/2 -inch. These.numbers might increase by a factor
of 2 to account for potential deep-seated hydroconsolidation.
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' April 11, 2001 - 13 - File No.: 08119-01
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' Frictional and Lateral Coefficients: Lateral loads may be resisted by soil friction on the base of
the 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 to 0.23 of dead load forces. A one-third (1/3) increase in the passive pressure may be
used when calculating resistance to wind or seismic loads. Lateral passive resistance is based on
' the assumption that any required backfill adjacent to foundations is properly compacted.
5.5 Slabs -on -Grade
' Subgrade: Concrete slabs -on -grade and flatwork should be supported by compacted soil placed
in accordance with Section 5.1 of this report.
' Vapor Barrier: In areas of moisture sensitive floor coverings, an appropriate vapor barrier
should be installed to reduce moisture transmission from the subgrade soil to the slab. For these
areas an impermeable membrane (10 -mil moisture barrier) should underlie the floor slabs. The
' membrane should be covered with me es o san o e p protect it during construction and to
aide in concrete curing. The la.lightly moistened just prior to placing the concrete.
Low -slump concrete should be used to help reduce the potential for concrete shrinkage. The
' effectiveness of the moisture barrier is dependent upon its quality, method of overlapping, its
protection during construction, and the successful sealing of the barrier around utility lines.
' Slab thickness and reinforcement:. Slab thickness and reinforcement of slab -on -grade are
contingent on the recommendations of the structural engineer or architect and the expansion
index of the supporting soil. Based upon. our findings, a modulus of subgrade reaction of
' - approximately 200 pounds per cubic inch can be used in concrete slab design for the expected
very low expansion subgrade.
' Concrete slabs and flatwork should be a minimum of 4 inches thick. We suggest that the
concrete slabs be reinforced with a minimum of o. 3re ar - nters, both horizontal
directions, placed at slab mid -height to resist swell forces and 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 (1/4 of slab depth) within 8 hours of
' concrete placement. Construction (cold) joints should consist of thickened butt joints with one-
half inch dowels at 18 -inches on center or a thickened keyed joint to resist vertical deflection at
the point. All construction points 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.
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Curing and Quality Control: The contractor should take precautions to reduce the potential of
curling of slabs in this and desert region using proper batching, placement, and curing methods.
Curing is highly effected by temperature, wind, and humidity. Quality control procedures may
be. used including trial batch mix designs, batch plant inspection, and on-site special inspection
and testing. Typically, using 2500 -psi concrete, many of these quality control procedures are not
required.
5.6 Retaining Walls
9
The following table presents lateral earth pressures for use in retaining wall design. The values
are given as equivalent fluid pressures without surcharge loads or hydrostatic pressure.
Lateral -Pressures and Sliding Resistance
Granular Backfill
Passive Pressure
300 pcf -level ground
Active Pressure (cantilever walls)
35 pcf - level ground
Use when wall is permitted to rotate 0.1 % of wall height
At -Rest Pressure (restrained walls)
55 pcf - level ground
Dynamic Lateral Earth Pressure
Acting at mid height of structure,
21H psf
Where H is height of backfill in feet
Base Lateral Sliding Resistance
I `
Dead load x Coefficient of Friction:
0.50
Notes:
1. These values are ultimate values. A factor of safety of 1.5 should be used in stability analysis except
for dynamic earth pressure where a factor of safety of 1.2 is acceptable.
2. Dynamic pressures are based on the Mononobe-Okabe 1929 method, additive to active earth pressure.
Walls retaining less than 6 feet of soil need not consider this increased pressure.
Upward sloping. backfill or surcharge loads
pressures. Should any walls be considered
foundations, our office should be contacted f
loads should be considered if they exist within
projected 45 degrees upward from the base of
should be taken as 35% of the surcharge load
traffic loads should include a uniform surcharge
)m nearby footings 'can create larger lateral
retaining sloped backfill or placed next to
recommended design parameters. Surcharge
zone between the face of the wall and a plane
e wall. The increase in lateral earth pressure
ithin this zone. Retaining walls subjected to
Ad equivalent to at least 2 feet of native soil.
Drainage: A backdrain or an equivalent system lof 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 Itop 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: Compac
horizontal distance equal to one wall height
lightweight compaction equipment. This is
pressures caused by compaction with heav
preparation should be as specified in Section 5.1
EARTH
n on the retained side, of the wall within a
uld be performed by hand -operated or other
tended to reduce potential locked -in lateral
grading equipment. Foundation subgrade
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5.7 Mitigation of Soil Corrosivity on Concrete
Selected chemical analyses for corrosivity were conducted on samples at the project site. The
native soils were found to have moderate to severe sulfate ion concentration (0.10 to 0.20%) and
moderate chloride ion concentration (0.09%). Sulfate ions can attack the cementitious material
in concrete, causing weakening of the cement matrix and eventual deterioration by raveling.
Chloride ions can cause corrosion of reinforcing steel. The Uniform Building Code does not
require any special provisions for concrete for these low concentrations as tested. The Uniform
Building Code requires for severe sulfate conditions that Type V Portland Cement be used with a
maximum water cement ratio of 0.45 using a 4,500 psi concrete mix (UBC Table 19-A-4).
A minimum concrete cover of three (3) inches should be provided around steel reinforcing or
embedded components exposed to native soil or landscape water (to 18 inches above grade).
Additionally, the concrete should be thoroughly vibrated during placement.
-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. A qualified corrosion engineer should be
consulted regarding mitigation of the corrosive effects of site soils on metals.
5.8 Seismic Design Criteria
' This site is subject to strong ground shaking due to potential fault movements along the
San Andreas and San Jacinto Faults. Engineered design and earthquake -resistant construction
increase safety and allow development of seismic areas. The minimum seismic design should
' comply with the latest edition of the Uniform Building Code for Seismic Zone 4 using the
seismic coefficients given in Section 3.4.3.
' The UBC seismic coefficients are based on scientific knowledge, engineering judgment, and
compromise. Factors that play an important role in dynamic structural performance are:
(1) Effective peak acceleration (EPA),
(2) Duration and predominant frequency of strong ground motion,
(3) Period of motion of the structure,
(4) Soil -structure interaction,
(5) Total resistance capacity of the system,
(6) Redundancies,
(7) Inelastic load -deformation behavior, and
(8) Modification of damping and effective period as structures behave inelastically:
Factors 5 to 8 are included in the structural ductility factor (R) that is used in deriving a reduced
value for design base shear. If further information on seismic design is needed, a site-specific
probabilistic seismic analysis should be conducted.
The intent of the UBC lateral force. requirements is to provide a structural design that will resist
collapse to provide reasonable life safety from a major earthquake, but may experience some
structural and nonstructural damage. A fundamental tenet of seismic design is that inelastic
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April 11, 2001 - 16 - File No.: 08119-01
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yielding is allowed to adapt to the seismic demand on the structure. In other words, damage is
allowed. The UBC lateral force requirements should be considered a minimum design. 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 has the responsibility
to interpret and adapt the principles of seismic behavior and design to each structure using
experience and sound judgment. The design engineer should exercise special care so that all
components of the design are all 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 were 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 necessary 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.
PRELIMINARY RECOMMENDED PAVEMENTS SECTIONS
R -Value SubQrade Soils - 50 (assumed)
Design Method — CAT.TRANS 1995
Notes:
1. Asphaltic concrete should be Caltrans, Type B, 1/2 -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 18 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 @ 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
Concrete Base
Cement Base
Index
Pavement Use
Thickness Thickness
Concrete Thickness
(Assumed)
(Inches) (Inches)
(Inches) (Inches)
4.0
Auto Parking Areas
2.5 4.0
4.0 4.0
5.0
Drive Lanes
3.0 4.0
5.0 4.0
Notes:
1. Asphaltic concrete should be Caltrans, Type B, 1/2 -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 18 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 @ 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
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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
conditions of a property can occur with passage of time whether they are from natural processes
or works of man on this or adjoining properties. In addition, changes in applicable standards
' occur whether they result from legislation or broadening of knowledge. Accordingly, findings of
this report may be invalidated wholly or partially by changes outside our control. Therefore, this
report is subject to review and should not be relied upon after a period of one year.
' In the event that any changes in. the nature, design, or location of structures are planned, the
conclusions and recommendations contained in this report shall not be considered valid unless
' - the changes are reviewed and conclusions of this report are modified or verified in writing.
This report is issued with the understanding that the owner, or the owner's representative, has the
' responsibility to bring the information and recommendations contained herein to the attention of
the architect and engineers for the project so that they are -incorporated into the plans and
specifications for the project. The owner, or the owner's representative, also has the
' responsibility to take the necessary steps to see that the general contractor and all subcontractors
follow such recommendations. It is further understood that the owner or the owner's
' representative is responsible for submittal of this report to the appropriate governing agencies.
As the Geotechnical Engineer of Record for this project, Earth Systems Southwest (ESSW) has
striven to provide our services in accordance with generally accepted geotechnical engineering
practices in this locality at this time. No warranty or guarantee is express or implied. This report
was prepared for the exclusive use of the Client and the Client's authorized agents.
' ESSW should be provided the opportunity for a general review of final design and specifications
in order that earthwork and foundation recommendations may be properly interpreted and
implemented in the design and specifications. If ESSW is not accorded the privilege of making
' this. recommended review, we, can assume no responsibility for misinterpretation of our
recommendations.
' Although available through ESSW, .the current scope of our services does not include an
environmental assessment, or investigation for the presence or absence of wetlands, hazardous or
toxic materials in the soil, surface water, groundwater or air on, below, or adjacent to the subject
property.
' - EARTH SYSTEMS SOUTHWEST
' April 11 2001' ' 18 File No.: 08119-01
,
01-04-716
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 monitoringand testing would be additional services provided b our firm. The
g P Y
costs of these services are not included in our present. fee arrangements, but can be obtained from
' our office. The recommended review, tests, and observations include, but are not necessarily
limited to the following:
' • Consultation during the final design stages of the project.-
• Review of the building and grading plans to observe that recommendations of our report
' have been properly implemented into the design.
• Observation and testing during site preparation, grading and placement of engineered fill
' as required by UBC Sections 1701 and 3317 or local grading ordinances.
• Consultation as required during construction.
000
Appendices as cited are attached and complete this report.
EARTH SYSTEMS SOUTHWEST ,�
' April 11, 2001 _19- File No.: 08119-01
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' REFERENCES
' Abrahamson, N., and Shedlock; K., editors, 1997, Ground motion attenuation relationships:
Seismological Research Letters, v. 68, no. 1, January 1997 special issue, 256 p.
' American Concrete Institute (ACI), 1996, ACI Manual of Concrete Practice, Parts 1 through 5.
American Society of Civil Engineers (ASCE), 2000, ASCE Standard 7-98, Minimum Design Loads
' for Buildings and Other Structures.
Blake, B.F., 2000, FRISKSP v. 4.00, A Computer Program for the Probabilistic Estimation of Peak
Acceleration and Uniform Hazard Spectra, Using 3-D Faults as Earthquake Sources, Users
Manual.
Boore, D.M., Joyner, W.B., and Fumal, T.E., 1993, Estimation of Response Spectra and Peak
Accelerations from Western North American Earthquakes: An Interim Report; U.S.
Geological Survey Open -File Report 93-509,15 p.
Boore, D.M.; Joyner, W.B., and Fumal, T.E., 1994; Estimation of Response Spectra and Peak
Acceleration from Western North American Earthquakes: An Interim Report, Part2,
' U.S. Geological Survey Open -File Report 94-127
California Department of Conservation, Division of Mines and Geology (CDMG), 1997, Guidelines
for Evaluating and Mitigating Seismic Hazards in California, Special Publication 117.
California Department of Water Resources, 1964, Coachella Valley Investigation, Bulletin No. 108,
146 pp.
Department of Defense, 1997, Soil Dynamics and Special Design Aspects, MIL-HDBK-1007/3,
superseding NAVFAC DM 7.3.
Department of the Navy; Naval Facilities Engineering. Command (NAVFAC), 1986,
Foundations and Earth Structures, NAVFAC DM 7.02.,
' Envicom Corporation and the Count of Riverside Planning Department, 1
rp y g976, Seismic Safety
and Safety General Plan Elements Technical Report, County of Riverside.
' Ellsworth W.L. 1990 "Earthquake Histo 1769-1989 .in: The San Andreas Fault System,
q History, Y ,
California: U.S. Geological Survey Professional Paper 1515, 283 p.
' Federal Emergency Y(FEMA enc Management A , 1997 NEHRP Recommended Provisions for
g g )
Seismic Regulations for New Buildings and Other Structures, Part 1 — Provisions and Part 2 -
Commentary.
Hart, E.W., 1994, Fault -Rupture Hazard Zones in California: California Division of Mines and
' Geology Special Publication 42, 34 p.
International Conference of Building Officials, 1997, Uniform Building Code, 1997 Edition.
International Conference of Building Officials, 2000, International Building Code, 2000 Edition.
t. EARTH SYSTEMS SOUTHWEST
' April 11, 2001 -20- File No.: 08119-01
01-04-716
Jennings, C.W, 1994, Fault Activity Map of California and Adjacent Areas: California Division of
Mines and Geology, Geological Data Map No. 6, scale 1;750,000.
' Petersen M.D. Bryant, W.A. Cramer C.H. Cao T. Reichle M.S. Frankel A.D. Leinkaem er
J.J., McCrory, P.A., and Schwarz, D.P., 1996, Probabilistic Seismic Hazard Assessment for
' the State of California: California Division of Mines and Geology Open -File Report 96-08.
Prakash, S., 1982, Soil Dynamics, McGraw-Hill Book Company
' Proctor, R. J., 1968, Geology of the Desert Hot Springs - Upper ` Coachella Valley Area,
California Division of Mines and Geology, DMG Special Report 94.
Reichard, E.G. and Mead, J.K., 1991, Evaluation of a Groundwater Flow and Tranps ort Model of
the Upper Coachella Valley, California, U.S.G.S. Open -File Report 91-4142..
' Riverside County Planning Department, 1984, Seismic Safety Element of the Riverside County
General Plan, Amended.
Rogers, T.H. 1966 Geologic Map. of California- Santa Ana Sheet California Division of Mines
g to P ,
and Geology Regional Map Series, scale 1:250,000.
Sieh, K., Stuiver, M., and Brllinger, D., 1989, A More Precise Chronology of Earthquakes
Produced by the San Andreas Fault in Southern Califomia: Journal of Geophysical
' Research, Vol. 94, No. B1, January 10, 1989, pp. 603-623.
Structural Engineers Association of California (SEAOC), 1996, Recommended Lateral Force
Requirements. and Commentary.
Tokimatsu, K, and Seed, H.B., 1987, Evaluation of Settlements in Sands Due To Earthquake
' Shaking, ASCE, Journal of Geotechnical Engineering, Vol. 113, No. 8, August 1987.
Van de Kamp, P.C., 1973, Holocene Continental Sedimentation in the Salton Basin, California: A
' Reconnaissance, Geological Society'of America, Vol. 84, March 1973.
Working Group on California Earthquake Probabilities, 1995, Seismic Hazards in Southern
California: Probable Earthquakes, 1994-2024: Bulletin of the Seismological Society of
America, Vol. 85, No. 2, pp; 379-439.
' Wallace, R. E.,. 1990, The San Andreas Fault System, California: U.S. Geological Survey
Professional Paper 1515, 283 p.
' . EARTH SYSTEMS SOUTHWEST
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. � � .3 j+♦' «sw; S
ik
�.1;- ,.#fi �. S." .. dTJ `e14p ,' 'o-� �s.� �.. � 1 �;
•iii',,.
Kr '.'1N r� r,s '�11� ` „°m�..
Y.
�.f�Y- x� �"'" eyt��'c �..•.f ;•4
"1'
a
4f. d��(�♦ + . . `
r y
�'S � /`a,+. y'�� il{ {a � '+ .+ni'
i.
� � !'TifyJl •)'
1. .ptt �°n "S` B P i Jd °i4 •M' -T
ti's
♦ °.
s
�',+e:•'
kya
Of
`-
sm
', � • � � 7 '��,
vD. ' °�
'2x1 i i `+ ...♦� x y3 !_ k
t r. .
�
`. N •r f
�' � ^�'et�' �. P
9' to < YiY�b#, (�� -
x Y
V .�.5
v �PcBr
�4
-
,V, (• rtrFX i
�`
d+� '.' p� :itlT
IwQ. .1."
lQi k!L. <
J "ai+!�k�t'✓ f, �i'J —
Y ({ilSGS
Figure 1--Site.Vicinity
Caleo Bay :Commercial° Development
Project No.: 08119-01
a
Earth Systems
Southwest,
ICaleo Bay Commericial
Table 1
Fault Parameters &
08119-01
San Andreas - Banning Branch
do Ueterminimic Estimates of mean reaK t�roun4 Acceleration (rUA
9.8
SS
A
7.1
Maximum
Avg
Avg
Date of
Largest
Mean
Fault Name or
Distance Fault
Magnitude
Slip
Return
Fault Last
Historic
Site
Seismic Zone
from Site Type
Mmax
Rate
Period
Length Rupture
Event
PGA
9.6
(mi) (km) UBC
(Mw)
(mm/yr)
(yrs)
(km) (year)
>5.5M (year)
(g)
Reference Notes: (1)
(21. (3)
(4)
(2)
(2)
(2)
(5)
(6)
San Andreas - Banning Branch
6.1
9.8
SS
A
7.1
10
220
98
6.2
1986
0.37
San Andreas - Southern (C V +S B M)
6
9.6
SS
A
7.4
24
220
203
c. 1690
0.41
San Andreas - Coachella Valley
6
9.6
SS
A
7.1
25
220
95,
c. 1690
0.37
San Andreas - Mission Crk. Branch
6
9.7
SS
A •
7.1
25
220
95
6.5
1948
0.37
Blue Cut
14
23
SS
C
6.8
1
760
30
--
0.16
San Jacinto (Hot Spgs - Buck Ridge)
17
27
SS
C
6.5
2
354
70
6.3
1937
0.12
Burnt Mountain
17
28
SS
B
6.4
0.6
5000
20
1992
7.3
1992
0.11
Eureka Peak
18
29
SS
B
6.4
0.6
5000
19
1992
6.1
1992
0.10
San Andreas - San Bernardino Mtn.
18
29
SS
A
7.3
24
433
107
1812
7.0
1812
0.17
San Jacinto -Anza
21
34
SS
A
7.2
12
250
90
1918
6.8
1918
0.14
San Jacinto - Coyote Creek
21
34
SS
B
6.8
4
175
40
1968
6.5
1968
0.11
Morongo
28
46
SS
C
6.5
0.6
1170
23
5.5
1947
0.07
Pinto Mountain
30
48
SS
B
7.0
2.5
500
73
0.09
Emerson So. - Copper Mtn.
32
51
SS
B
6.9
0.6
5000
54
--
0.08
Landers
32
52
SS
B
7.3
0.6
5000
83
1992
7.3
1992
0.10
Pisgah -Bullion Mtn. -Mesquite Lk
34
55
SS
B
7.0
0.6
5000
88
1999
7.1
1999
0.08
San Jacinto - Borrego Mountain
35
57
SS
B
6.6
4
175
29
6.5
1942
0.06
San Jacinto -San Jacinto Valley
36
58
SS
B
6.9
12
83
42
6.8
1899
0.07
Earthquake Valley
40
64
SS
B
6.5
2
351
20
0.05
Brawley Seismic Zone
42
67
SS
B
6.4
25
24
42
5.9
1981
0.04
Johnson Valley (Northern)
43
69
SS
B
6.7
0.6
5000
36
--
0.05
North Frontal Fault Zone (East)
44
70
DS
B
6.7
0.5
1730
27
0.06
Elsinore - Julian
44
71
SS
A
7.1
5
340
75
0.06
Calico -Hidalgo
45
72
SS •
B
7.1
0.6
5000
95
0.06
Elsinore - Temecula
47
76
SS
B
6.8
5
240
42
0.05
Lenwood-Lockhart-Old Woman Spgs
49
78
SS
B
7.3
0.6
5000
149
0.06
Elmore Ranch
50
81
SS
B
6.6
1
225
29
1987
5.9
1987
0.04
Elsinore -Coyote Mountain
51
83
SS
B
6.8
4
625
38
0.04
San Jacinto - Superstition Mountain
54
86
SS
B
6.6
5
500
23
c. 1440
--
0.04
San Jacinto - Superstition Hills
55
88
SS
B
6.6
4
250
22
1987
6.5
1987
0.04
North Frontal Fault Zone (West)
56
90
DS
B
7.0
1
1310
50
0.05
Helendale - S. Lockhardt
56
91
SS
B
7.1
0.6
5000
97
0.05
San Jacinto -San Bernardino
58
94
SS
B
6.7
12
100
35
6.0
1923
0.04
Notes:
'1. Jennings (1994) and CDMG (1996)
2. CDMG & USGS (1996), SS = Strike -Slip, DS = Dip Slip
3. ICBO (1997), where Type A faults: Mmax > 7 and slip rate >5 mm/yr &Type C faults: Mmax <6.5 and slip rate < 2 mm/yr
'4. CDMG (1996) based on Wells & Coppersmith (1994), Mw = moment magnitude
5. Modified from Ellsworth Catalog (1990) in USGS Professional Paper 1515
6. The estimates of the mean Site PGA are based on the following attenuation relationships:
Average of: (1) 1997 Boore, Joyner & Fumal; (2) 1997 Sadigh et al; (3) 1997 Campbell
' (mean plus sigma values are about 1.6 times higher)
Based on Site Coordinates: 33.707 N Latitude, 116.293 W Longtude and Site Soil Type D
EARTH SYSTEMS SOUTHWEST
Caleo Bay Commericial
0.65
0.12
08119-01
0.20
1.00
0.30
1.00
0.60
1.00
Table 2
0.86
2000 International Building Code (IBC) Seismic Parameters
Seismic Category
0.90
D
Table 1613.3(1)
Site Class
1.10
D
Table 1615:1.1
Latitude:
1.30
33.707 N
1.40
Longitude:
1.50
-116.293 W
1.60
Maximum Considered Earthquake (MCE)
Ground Motion
Short Period Spectral Reponse
Ss
1.50 g
Figure1615(3)
1 second Spectral Response
SI
0.60 g
Figurel615(4).
Site Coefficient
- Fa
1.00
Table 1615.1.2(1)
Site Coefficient
FV
1.50
Table 1615.1.2(2)
SMs
1.50 g
= Fa*Ss - -
SMI
0.90 g
= Fv*Sl
Design Earthquake Ground Motion
Short Period Spectral Reponse
SDS
1.00 g
= 2/3*SMs
1 second Spectral Response
SDI
0.60 g
= 2/3*SMl
To
0.12 sec
= 0.2*SDI/SDs
Ts
0".60 sec
= SDS/SDs
Period Sa
2000 IBC -Equivalent Elastic
Static Response Spectrum
T (sec) (g
0.00 0.40
1.2
1.0
rn
m
U)
0.8
0
CO -
(D
a� 0.6
U
U
Q
0.4
m
Q
Z,
0.0 L
0.0
0.5 1.0 1.5
Period (sec),
EARTH SYSTEMS SOUTHWEST
2.0
0.05
0.65
0.12
1.00
0.20
1.00
0.30
1.00
0.60
1.00
0.70
0.86
0.80
0.75
0.90
0.67
1.00
0.60
1.10
0.55
1.20 -
0.50
1.30
0.46
1.40
0.43
1.50
0.40
1.60
0.38
1.70
0.35
1.80
0.33
1.90
0.32
2.00
0.30
2.20
0.27
Earth Systems
` l Southwest 79-811 B Country Club Drive, Bermuda Dunes, CA 92201
ni,,..,anFmzec_icsv r:exn�mzec_-rzic
Boring No.:B - I
Drilling Date: March 8, 2001
Project Name: Caleo Bay Commercial Development
Drilling Method: 8" Hollow Stem Auger
File Number: 08119-01
'
Drill Type: .Mobile B-61 w/ Autohammer
Boring Location: See Figure 2
Logged By: Karl A. Harmon
vSample
Type
Penetration
Description of Units [Pagel of 1
ML
Resistance
-0
Q
=
Note: The stratification lines shown represent the
p
o
7,11,18
85
° c
approximate boundary between soil and/or rock types Graphic Trend
q
7; a
(Blows/6")
�-
q
V
and the transition may be gradational. Blow Count Dry Density
0
5
10
15
20
25
30
35
40
45
50
55
SM
SILTY SAND: Light olive, loose; damp, fine
'
grained, concrete slab encountered at -4 inches
ML
SILT: Light olive, medium dense, damp
7,11,18
85
7
7, t 0, l t
SM
SILTY SAND: Light olive, medium dense, dry to
damp, fine grained, some SP -SM
7, 9, 15
93 '
2'
damp, fine to very fine grained, lenses of silt and sandy silt
6, 11, 12
medium dense to dense, lenses of SP -SM
6 9, 16
86
2
12 13
SP -SM
SAND: Light olive; dense, dry to damp, fine to
medium grained, some silty sand
TOTAL DEPTH: 30.0 feet
No Groundwater or Bedrock Encountered
a
Earth Systems
1� Southwest 79-81111 Country Club Drive, Bermuda Dunes, CA 92201
Phn !76011di_1SRR FAX!76011d5_711S
Boring No.:B - 2
Drilling Date: March 8, 2001
Project Name:
Caleo Bay Commercial Development
SP-Srvt
Drilling Method: 8" Hollow Stem Auger
File Number:
08119-01
Drill Type: Mobile B-61 w/ Autohammer
Boring Location: See Figure 2
Logged By: Karl A. Harmon
Sample
Y
Page 1 I
J
Type
Penetration
l
L\
of
Description of Units 0
v
s
Resistance
u
q
B y
•= q
Note: The stratification lines shown represent the
c
o
4, 5, 7
c
approximate boundary between soil and/or rock types Graphic Trend
C)
ISa
n
(Blows/6")
V)
Q
0
and the transition may be gradational. Blow Count Density
�y ty
-0
SP-Srvt
SAND: Light olive, medium dense, damp, fine
grained
4, 8, 10
100
l
4, 5, 7
ML
SANDY SILT: Light olive, medium dense, dry to
damp, some silty sand,
- 10
sM
SILTY SAND: Light olive -gray, medium dense, dry
3, 5, 9
77
1
to damp, fine to very fine grained, some SP -SM .
- 15
5, 7, 7
lenses of silt
- 20
5, 10, 12
- 25
3, 5, 7
- 30
TOTAL DEPTH: 29.O feet
n
No Groundwater or Bedrock Encountered
- 35
- 40
- 45
- 50
- 55
Earth Systems
Southwest 79-811B Country Club Drive, Bermuda Dunes, CA 92201
" Phnnr /7601 id5_1SRR FAX !7601 'id5_7Z 15
Boring No.:B - 3
Drilling Date: March 8, 2001
Project Name: Caleo Bay Commercial Development
Drilling Method: 8" Hollow Stem Auger .
File Number: 08119-01
SM
SILTY SAND: Light olive, loose to medium dense,
Drill Type: Mobile B-61 w/ Autohammer
Boring Location- See Figure 2
Logged By: Karl A. Harmon
v
Sample
Type
Penetration
i
�.�
Description of Units [Page 1 of 1
7; 9, 11
3_*Resistance
'D
U
p
-. W"
Note: The stratification lines shown represent the
a
o
Z
c
approximate boundary between soil and/or rock types Graphic Trend
q
nF
m rn • �
(Blows/6")
rn
p
� j
and the transition may be gradational. Blow Count Density
Dr
-0
-5'
nut
- 15
- 20
- 25
- 30
- 35
-40
- 45
- 50
- 55
1
ML
SILT: Light olive, loose, damp
SM
SILTY SAND: Light olive, loose to medium dense,
dry to damp, fine grained, interbedded layers of
7; 9, 11
sandy silt
ML
SILT: Light olive, medium dense, damp to moist,
lenses of silty clay.
3, 7, 10
79
12
SM
SILTY SAND: Olive, medium dense, damp, fine
grained, interbedded lenses and layers of silt
5, 7, 8
ML _
SANDY SILT: Light olive, medium dense, damp,
some silty sand
4, 7, 12
80
7
SP -SM
SAND: Light olive -gray, medium dense, dry to
damp, fine grained, some SP -SM
4 7 10
t
R
sm.
SILTY SAND: Olive, medium dense, damp, fine to
very fine grained; some SP -SM
6, 11, 17
damp to moist
ML
SILT: Light olive, medium dense, damp, some very
4,10,20-
fine sand
SM'
SILTY SAND: Light olive -brown, medium dense,
damp, fine to very fine grained, some sandy silt
6, 7, 12
SP -Slut
SAND: Light olive -brown, dense, damp, fine
grained
8,18,30
TOTAL DEPTH: 51.5 feet
No Groundwater or Bedrock Encountered
' Earth Systems
~� Southwest 79-811B Country Club Drive, Bermuda Dunes, CA 92201
Phn (7AA1 1Ai_1 SRR FAX IUAN id S_711 G
Boring No.•B - 4
Drilling Date: March 8, 2001
Project Name: Caleo Bay Commercial Development
Drilling Method: 8" Hollow Stem Auger
File Number: 08119-01
Drill Type: Mobile B-61 w/ Autchammer
Boring Location: See Figure 2
Logged By: Karl A. Harmon
dry to damp, fine .to very fine grained, lenses of silt
Sample
Type
Penetration
Y
7
Pae 1 of ]
Description of Units g
t;
r
a
Resistance
U p
c
= c°,
Note: The stratification lines shown represent the
n
v
approximate boundary between soil and/or rock types Graphic Trend
p
N 0
(Blows/6")
rn
q
� j
and the transition may be gradational. _ Blow Count Dry Density
79
3
interbedded with sandy silt and silty sand
-0
-5
- 10
- 15
- 20
- 25
- 30
- 35
-40
- 45
- 50
- 55
SM
SILTY SAND: Light -olive-brown, medium dense,
dry to damp, fine .to very fine grained, lenses of silt
4, 4, 5
ML
SILT: Light olive, medium dense, damp,
8, 11, 12
79
3
interbedded with sandy silt and silty sand
5; 7, 8
SM
SILTY SAND: Light olive, medium dense, dry to
damp, fine to very fine grained
3, 8, 13
ML
79
5
BANDY SILT: Olive, medium dense, damp, some
clayey silt lenses, some silty sand
ML
SILT: Olive, medium dense, damp to moist, trace
7, 9, 12
very fine sand
6, 8, 12
108
2
interbedded lenses of sandy silt and silty sand
SM
SILTY SAND: Light olive -brown, medium dense,
damp, fine tovery fine grained
4,6 '
,6, 9
TOTAL DEPTH: 34.0 feet
No Groundwater or Bedrock Encountered
3
Earth Systems
d' Southwest 79-811B Country Club Drive, Bermuda Dunes, CA 92201
• Uh- 11 AIIAcAdds 17Avnam•iA<7i�<
Boring No.:B - 5
Drilling Date: March 8, 2001
Project Name: Caleo Bay Commercial Development
Drilling Method: 8" Hollow Stem Auger
File Number: 08119-01
Drill Type: Mobile B-61 w/ Autohammer
Boring Location: See Figure 2
Logged By: Karl A. Hannon
t
Sample
Type
Penetration
__
�.
7 v
[Pagel of 1
Description Of Units
Q-
Resistance
6.5 ft.
U
Cn
)
q
=
e
Note: The stratification lines shown represent the
p
o
- �
�,�
approximate boundary between soil and/or rock types Graphic Trend
q
w
o vz
(Blows/6")
v)
q
t j
and the transition may be gradational. Blow Count D Density
Dry
0
5
} 10
15
20
25
30
35
40
45
50
55
SM
SILTY SAND: Gray, medium dense to dense, dry,
fine grained, lenses of SP -SM, clayey silt layer @
6.5 ft.
8, 15, 15
100
3
Iv1L
SILT: Olive -brown, medium dense, damp to moist,
interbedded sandy and clayey
4, 7, 9
SM
SILTY SAND: Olive -brown, medium dense, damp,
fine to very fine grained, some sandy silt
.
4, 6, 10
87
2
4'6'9
SP -SM
SAND: dense, dry to damp, sample lost
5, 12,20
ML
SILT: Light olive, dense, damp, some very fine sand
10, 12, 14
6, 18,26
87
3
Light olive -gray, interbedded sandy and silty, some silty
sand
ML
Y
SANDY SILT: Light olive -gray, dense, damp, some
very fine silty sand
6, 12, 12
,
TOTAL DEPTH: 40.0 feet
No Groundwater or Bedrock Encountered
1 APPENDIX B
Laboratory Test Results
File No.: 08119-01 April 11, 2001
UNIT. DENSITIES AND MOISTURE CONTENT ASTM D2937 & D2216
' Job Name: Caleo Bay Commercial Development, La Quinta
BI
5
Unit
Moisture
USCS
Sample
Depth
Dry ;
Content
Group
Location
(feet)
Density (pcf)
(%)
Symbol
BI
5
85.
7'
ML
'
B1
15;.
93 ;
2
SM
B1
25
86
2
SM
' B2 .
2.5
100
1
SP -SM
M
B2
'12.5
77
1
SM
' B3
10
79
12
ML
B3
20'
80
7
ML
B3
30
91
3
SM
' B3
40
85
6
ML
B3
50
104_
1
SP -SM
' B4
7.5
79
3
ML
B4
17.5
79
5
ML
' B4
27.5
108
: ' 2
ML
B5
5
100
3
SM
B5.
15
'. -,87
:' 2
SM
B5
35
87
3 .
ML
. -
'EARTH SYSTEMS SOUTHWEST
File No.: 08119-01
April 11, 2001
PARTICLE SIZE ANALYSIS
ASTM D-422
Job Name: -Caleo Bay Commercial Development, La Quinta
Sample ID: B1 @ 1-4' Feet
Description: Silty Sand: fine grained with trace gravel (SM)
Sieve Percent
Size Passing
1-1/2" 100
1 " 100
3/4" 100
1/2" 100",-
3/8' 99
#4 99.
#8 98
#16 98
% Gravel:
1
#30 97
% Sand:
74
#50 91
% Silt:
19
#100 43
% Clay (3 micron):
6
#200: 25
(Clay content by short hydrometer
method)
100
90
80
70
= 60
50
c
d
U
a 40
30
20
10
0
100
0.001
File No.: 08119-01
April 11, 2001
' PARTICLE SIZE ANALYSIS
ASTM D-422
Job Name:
Caleo Bay Commercial Development, La Quinta
Sample ID:
133 @ 5' Feet
'
Description:
Silty Sand: fine grained (SM)
Sieve Size Passing
By Hydrometer
Method:
'
%o
3" 100
Particle Size % Passing
2" 100
53 Micron
30
1-1/2" 100
22 Micron
9
'
1" 100
13 Micron
7
3/4" 100
7 Micron
5
1/2" 100
5 Micron
4-
'
3/8" 100
3.4 Micron
4
#4 100
2.7 Micron
4
'
#8 100
1.4 Micron
2
#16 -10.0
#30 100
% Gravel:
0
'
#50 -99
% Sand:
61
#100 84
% Silt:
35
1
#200 39
% Clay (3 micron):
f
4
' 100
90 -
80
' 70
60
'
on
2 50
a
o
40 -
30
' 20
' ]0
0
100
10 1
0.1
0.01 0.001
'
Particle Size (mm)
EARTH SYSTEMS SOUTHWEST
File No.: 08119-01 April 11, 2001
CONSOLIDATION TEST ASTM D 2435 & D 5333
Caleo Bray Commercial Development, La Quinta Initial Dry Density: 71.0 pcf
133 @ 10' Feet Initial Moisture, %: 12.2%
Silt (ML) Specific Gravity (assumed): 2.67•
Ring Sample Initial Void Ratio: 1.347
Hydrocollapse:- 3,6% @2.0 ksf
% Change in Height vs Normal Presssure Diagram
--8 Before Saturation Hydrocollapse
® After Saturation — W Rebound
2
I
0
-2
mon -3.
x
-4
c�
-5
L
U
-6
a�
V
L -7
V
-8
-9
-10
-11
-12
File No.: 08119-01 April 11, 2001
CONSOLIDATION TEST ASTM D 2435 & D 5333
Caleo Bay Commercial Development, La Quinta- Initial Dry Density: 79.0 pcf
B4 @ 17.5' Feet Initial Moisture, %: 5.1 %
Sandy Silt (ML) Specific Gravity (assumed): 2.67
Ring Sample Initial Void Ratio: 1.111
Hydrocollapse: 2.2% @ 2.0 ksf
ti
% Change in Height vs Normal Presssure Diagram
Before Saturation ®Hydrocollapse
® After Saturation SIE 'Rebound
2
I
0
-1
-2
mon =3
x
-4
c 5
c�
s.
U
-6
u
L
d -7
a
-8
-9
-10
-11
-12 A
0.1 1.0
Vertical Effective Stress, ksf
EARTH SYSTEMS SOUTHWEST
File No.: 08119-01 April 11, 2001
MAXIMUM DENSITY / OPTIMUM MOISTURE ASTM D 1557-91 (Modified)
Job Name: Caleo Bay Commercial Development, La Quinta Procedure Used: A
Sample ID: B1 @ 1-4' Feet Preparation Method: Moist
Location: Native Rammer Type: Mechanical
Description: Brown; Silty Sand: fine grained with trace gravel (SM)
Sieve Size % Retained
Maximum Density: 111 pcf 3/4" 0.0
Optimum Moisture: 11% 3/8 0.0
#4 0.3
140
135
130
125
110
105
I of
W
5 10 15 20 25
Moisture Content, percent
EARTH SYSTEMS SOUTHWEST
File No.: 08119-01 April 11, 2001.
SOIL CHEMICAL ANALYSES
Job Name: Caleo. Bay Commercial Development, La Quinta
Job N6.': 08119-01
Sample ID: -13-1`1 B-2
Sample Depth, feet 1-4 '1-4
pH: 7.6
Resistivity (ohm -cm): 128 175
Chloride (Cl), ppm: 930 X910
Sulfate (SO4), ppm' 1,013 1,988 ,
Note: Tests performed by Subcontract Laboratory:
Soil & Plant Laboratory and Consultants, Inc.
79-607 Country Club Drive.
Bermuda Dunes, CA 92201 Tel` (760).172-799.5"'
General Guidelines for Soil Corrosivity
Chemical Agent
Amount in Soil,
Degree of Corrosivity
Soluble
Q A 000 ppm
Low
Sulfates
1000 - 2000 ppm
Moderate
2000 - 5000 ppm
Severe
> 5000 ppm
Very Severe
Resistivity
1=1000 ohm -cm
Very Severe
1000-2000 ohm -cm
Severe
2000-10;000 ohm -cm
Moderate
10,000+ ohm -cm I
Low