HomeMy WebLinkAboutDune Palms Bridge PFR_5-23-2015
PRELIMINARY FOUNDATION REPORT
For the
Dune Palms Low Water Crossing Replacement at the
Coachella Valley Storm Water Channel, La Quinta, California
City Project No. 2011-05, Federal Project No. BRLKS-5433(014)
Prepared for:
The City of La Quinta
Prepared by:
250 Big Sur Drive, Goleta, CA 93117
Phone: (805) 563-0788
May 18, 2015
Preliminary Foundation Report
Dune Palms Road Low Water Crossing at CVSWC Replacement Project
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Table of Contents
1.0 INTRODUCTION .................................................................................................... 1
1.1 PROJECT LOCATION ............................................................................................... 1
1.2 PROJECT DESCRIPTION .......................................................................................... 1
1.3 SCOPE OF WORK ................................................................................................... 2
2.0 SITE EXPLORATION ............................................................................................ 2
2.2 REVIEW OF EXISTING GEOTECHNICAL INFORMATION ................................................. 3
2.2 FIELD INVESTIGATION ............................................................................................. 3
2.3 LABORATORY TESTING ........................................................................................... 4
3.0 SITE CONDITIONS ................................................................................................ 4
3.1 SITE DESCRIPTION ................................................................................................. 4
3.2 GEOLOGIC SETTING ............................................................................................... 5
3.2.1 Regional Geology .......................................................................................... 5
3.3 SUBSURFACE CONDITIONS ..................................................................................... 5
3.3.1 Groundwater Conditions ................................................................................ 5
3.3.2 Subsurface Soil Conditions ........................................................................... 5
3.3.3 Engineering Properties of Subsurface Soils .................................................. 6
4.0 SEISMIC HAZARD ANALYSIS ............................................................................. 7
4.1 FAULTING AND SEISMICITY ...................................................................................... 7
4.2 FAULT RUPTURE HAZARD ....................................................................................... 8
4.3 DESIGN GROUND MOTION OR ARS CURVE .............................................................. 8
4.4 SECONDARY SEISMIC HAZARDS .............................................................................. 8
4.4.1 Soil Liquefaction Hazards .............................................................................. 8
4.4.2 Additional Secondary Seismic Hazards ......................................................... 8
5.0 ADDITIONAL NATURAL HAZARDS .................................................................... 9
5.1 FLOOD HAZARDS ................................................................................................... 9
5.2 SCOUR HAZARDS ................................................................................................... 9
5.3 CORROSION HAZARDS ........................................................................................... 9
6.0 PRELIMINARY FOUNDATION RECOMMENDATIONS ..................................... 10
6.1 GENERAL ............................................................................................................ 10
6.2 FOUNDATION TYPES............................................................................................. 10
6.3 PRELIMINARY PILE LENGTHS ................................................................................. 11
6.4 LATERALLY LOADED PILE DESIGN ......................................................................... 11
6.5 LATERAL EARTH PRESSURES ................................................................................ 12
6.6 FOUNDATION SETTLEMENT AND LATERAL DEFLECTION ........................................... 12
6.7 DRAINAGE CONSIDERATIONS ................................................................................ 12
7.0 CONSTRUCTION CONSIDERATIONS ............................................................... 13
8.0 LIMITATIONS ...................................................................................................... 14
REFERENCES
APPENDIX A, FIGURES AND PLATES
APPENDIX B, RESULTS OF FIELD EXPLORATION
APPENDIX C, RESULTS OF LABORATORY TESTING
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1.0 INTRODUCTION
The City of La Quinta plans to replace the existing low-water crossing over the Coachella Valley
Storm Water Channel at Dune Palms Road with a bridge, and contracted with Bengal Engineering
(BE) to prepare geotechnical reports for the subject project. BE explored the subsurface soil
conditions at the bridge site to provide geotechnical design and construction recommendations
for the proposed bridge structure and additional improvements. This work was performed for the
City of La Quinta in accordance with the signed Agreement, dated July 2, 2014.
This Preliminary Foundation Report (PFR), prepared as part of our scope of work, presents the
preliminary results of our site exploration and geotechnical analysis, and recommendations for
the design and construction of the proposed improvements.
This report is for use solely by the City of La Quinta, and its’ designated consultants, for the
specific project and the proposed project elements, and the scope of work described herein. Site
exploration findings, analyses performed, and conclusions/recommendations contained in this
report may not be adequate or appropriate for use by others, different project elements, and for
any other projects or purposes.
1.1 Project Location
The project site, as shown on Figure 1 in Appendix A, is located at the intersection of Dune Palms
Road with the Coachella Valley Storm Water Channel (CVSWC) in the City of La Quinta,
California. The existing at-grade low-water crossing is located approximately 1,000 feet north of
the intersection of Dune Palms Road and Highway 111. The approximate coordinates of the site
location, in terms of latitude and longitude, are about 33.710o and -116.277o, respectively.
1.2 Project Description
The project proposes to replace the existing at-grade low-water crossing at Dune Palms Road
with a bridge over the CVSWC in the City of La Quinta, Riverside County. The project will replace
the existing concrete roadway with a 480-foot long and 86-foot wide, four (4)-span bridge. The
new bridge will be a cast-in-place (CIP), pre-stressed concrete box girder-type and will be
supported by large-diameter pile/column extensions at the piers and seat type abutments founded
on smaller diameter piles.
The proposed bridge typical section consists of six-foot sidewalk on either side of the bridge, two
(2) eight-foot outside shoulders also serving as bike/golf cart lanes, a 9’-8” wide raised median,
two (2) eleven-foot travel lanes, and two (2) twelve-foot travel lanes.
The proposed improvements will include a significant vertical grade raise to meet the hydraulic
requirements of the Coachella Valley Water District (CVWD). The roadway at the bridge
approaches will be reconstructed to accommodate the raised profile. In order to match the
roadway section on the south side of the bridge, the project’s construction limits will be extended
to State Route 111. On the north side of the bridge, the project limits will be extended to include
a vacant lot north of the project area. The vacant lot is owned by the City and may be used for
storage and construction staging.
The project will maintain the existing roadway alignment/configuration. A temporary bypass road
will be constructed to allow staged construction of the bridge, and to maintain vehicle and
pedestrian access at all times.
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The Coachella Valley Association of Governments (CVAG) and the communities within the
Coachella Valley are working together on the implementation of a regional Bike/Pedestrian
corridor along Whitewater River and Coachella Valley Storm Water Channel. In accordance to
this plan, the project integrates into the southern slope protection a recreational trail under
crossing. It also includes a connector to the pedestrian and bike facilities along Dune Palms Road.
As a part of the bridge construction, concrete slope protection will be installed along the north
side of the channel. Additionally, minor removal and replacement of slope protection will be
required on the south side of channel west of the proposed bridge and extension of slope
protection approximately 300 feet downstream of the proposed bridge. The slope protection will
be based on revised CVWD standards for scour countermeasures.
1.3 Scope of Work
Bengal Engineering’s scope of work for this PFR included the following:
Site reconnaissance visits, and collection and review of available pertinent regional
and local geologic, seismic and geotechnical information.
Review of available, pertinent geotechnical data for public works or capital
improvement projects in the vicinity of the project site; mostly in the form of foundation
reports (FR) and Logs of Test Borings (LOTB).
Developed a scope of work for field and laboratory investigations; including the type,
locations and depths of exploration, sampling and testing.
Conducted a site-specific field exploration consisting of five (5) hollow-stem borings to
depths ranging from one hundred feet (100’) to one hundred twenty feet (120’) below
grade.
Conducted laboratory testing on the samples of representative site soils to evaluate
their engineering characteristics and design soil parameters.
A site-specific geotechnical seismic hazard evaluation, including a Probabilistic
Seismic Hazard Analysis (PSHA) to provide preliminary seismic design
recommendations for preliminary design of the proposed new structures.
Performed data review, analysis and interpretation to evaluate subsurface conditions,
and to provide preliminary recommendations on the foundation design and the
potential constructability issues or considerations.
Prepared this PFR to document the preliminary results of our geotechnical site
exploration, laboratory testing, data evaluations, and to provide preliminary design and
construction recommendations for the proposed project facilities.
2.0 SITE EXPLORATION
2.1 General
Available geotechnical investigations pertaining to the project site or the general area were
collected and reviewed, and site- and project-specific field exploration and laboratory testing were
performed to investigate the subsurface soil conditions, and to evaluate soil parameters for use
in the analysis and design of the proposed project facilities. Field exploration and laboratory
testing were performed in accordance with the applicable ASTM or the State of California
Standard Test Methods.
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2.2 Review of Existing Geotechnical Information
In preparing this report, we have reviewed the following geotechnical report pertaining to the
recent construction of the Adams Street Bridge, which is located approximately ½ mile upstream
of the existing Dune Palms crossing of the CVSWC.
Earth Mechanics, Inc. (2010), Final Foundation Report, Adams Street Bridge over
Whitewater River, City of La Quinta, California, EMI Project No. 08-167, dated June 2.
2.2 Field Investigation
Bengal’s field exploration, which consisted of five (5) exploratory hollow-stem borings, was
performed between Oct. 13-15, 2014 to investigate the subsurface soil conditions within and
adjacent to the footprint of the proposed bridge. The borings were extended to depths of 101.5’
(Borings B-1 and B-2) to 121.5’ (Borings B-3, B-4, and B-5) below grade, respectively. The
locations of the borings are shown on Figure 2 in Appendix A, and the logs are included in
Appendix B of this report.
Both disturbed and relatively undisturbed representative soil samples were retrieved from the
borings for laboratory testing. Soil samples were collected at 5-foot intervals above the 50-foot
depth and 10-foot intervals from below the 50-foot depth, respectively. Disturbed samples of the
subsurface soils were obtained using the Standard Penetration Tests (SPT) split spoon sampler.
Relatively undisturbed soil samples were collected using the Modified California (MC) Sampler.
The SPT sampler's cutting shoe and the barrel have a nominal inside diameter of 1.375 and 1.50
inches, respectively. The SPT barrel has a nominal outside diameter of 2.0 inches. Blow counts
to drive the samplers were also recorded at 6-inch intervals.
The subsurface soils encountered during drilling were visually classified and logged by a field
geologist. The soil descriptions in these boring logs were modified from the field descriptions,
when necessary, based on laboratory testing. Soil samples tested in the laboratory and the types
of tests performed are indicated on the log of test boring sheets. Blow counts needed to drive the
MC sampler 12 inches and the SPT sampler 18 inches are also presented in the logs.
All field investigations were performed in accordance with the applicable current ASTM Standards
(2014).
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2.3 Laboratory Testing
All soil samples collected during the field exploration were tested for in-situ moisture content.
Samples retrieved using the California Modified Sampler were also tested for in-situ soil density.
Several soil samples were selected for additional laboratory testing. The samples and the types
of laboratory tests performed were selected based on the project-specific needs. Our sub-
consultant, Matrix Geotechnical Consulting of Temecula, CA, performed the assigned laboratory
testing. These tests included:
Atterberg limits
Sieve/Gradation analysis
Consolidation
Collapse Potential
R-Value
Direct shear, and
Soil chemistry/corrosion
Laboratory tests were performed in accordance with the applicable American Society of Testing
and Material (ASTM, 2014) and/or State of California Standard Test Methods. Results of the
laboratory testing are included in Appendix C of this report.
3.0 SITE CONDITIONS
3.1 Site Description
The existing Dune Palms Road crossing is a 60-foot wide, two lane facility which is classified as
a “major collector” by Caltrans. The road crosses the CVSWC at a skew of approximately 18
degrees. The top width of the channel is approximately 460 feet. The channel bottom is earthen
and comprised of mostly fine-grained, sandy alluvial material. The south west bank channel side
slopes are currently paved with concrete for about 680 feet upstream. There is no concrete slope
paving on the north banks and southeast bank within the vicinity of Dune Palms Road.
The desert climate of La Quinta and the surrounding areas of the Coachella Valley is
characterized by mild winters and hot, dry summers. The drainage area tributary to the CVSWC
at the proposed Dune Palms Road Bridge is approximately 788 sq. mi. (USACE, 1980). The mean
seasonal precipitation in the area tributary to the Dune Palms Road crossing varies from 44 inches
at San Gorgonio Mountain to about 3 inches at the crossing. Flooding can result from rapid melting
of mountain snowpack, as well as occasional intense thunderstorms. The latter occur most
frequently during the winter months, between November and April, but may also happen as
monsoon storms during the summer and early fall (July through September). Storms are generally
of short duration but may result in several inches of rainfall in localized areas.
Underground utilities, aligned north-south and running parallel to the Dune Palms centerline, are
present in the summer crossing. Overhead power is present along the east side of the alignment.
A 54-inch diameter reclaimed water line, owned by the CVWD, runs parallel to the channel
centerline and is present within the project limits.
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3.2 Geologic Setting
3.2.1 Regional Geology
The Southern California region is located on the boundary of two crustal or tectonic plates: the
Pacific plate and the North American plate. Movement along these two plate boundaries causes
seismic activity such as earthquakes as the Pacific plate slides past the North American plate in
what is termed a right-lateral transform or strike-slip motion. The surface expression of this
tectonic movement is expressed by the northwest-trending system of faults known as the San
Andreas fault system, which runs from north of the San Francisco area to the Bombay Beach
area of the Salton Sea and includes a Coachella Valley segment located northeast of the project
site.
Coachella Valley forms the northerly part of the Salton Trough (at the lowest point of which is the
Salton Sea) which is a structural and topographic depression that is related to complex
interactions within the San Andreas Fault system and is considered the northward extension of
the Gulf of California. Offsets along various detachment faults produced Coachella Valley, which
progressively grew as the detachment faults moved. During this offset, sediments were dumped
from the topographic highs (mountains) to fill the lows (valleys) and developed geologic units in
such areas as the Indio and Mecca hills, which are now exposed.
Erosion of these elevated areas along with deposition from the Gulf of California and Colorado
River have provided as much as 12,000 feet of sediments in the basin. Soils of different ages and
compositions have developed on these sedimentary units, and on the younger alluvial units filling
the valley floor. Coachella Valley is underlain by a thick sequence of sedimentary deposits.
Mountains surrounding the valley include the Little San Bernardino Mountains to the northeast,
the foothills of the San Bernardino Mountains to the northwest, and the San Jacinto and Santa
Rosa Mountains to the southwest.
3.3 Subsurface Conditions
This section presents a preliminary description of the subsurface conditions based on the results
of the site exploration discussed above.
3.3.1 Groundwater Conditions
Groundwater was not encountered in any of the five (5) borings drilled as part of this investigation.
This finding is consistent with those borings drilled in 2010 for the foundation study at the Adams
Street Bridge crossing upstream (Earth Mechanics, 2010) of the subject project site.
3.3.2 Subsurface Soil Conditions
Our description of the soil conditions is based on field exploration and laboratory testing, and
review of available geotechnical information for the project vicinity.
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3.3.2.1 Earth Fill (ef)
Earth fill materials, where encountered (Boring B-5), consisted of light brown, fine-grained silty
sand (SM) which is medium dense, slightly moist, and contained occasional bits of trash.
Additional areas of earth fill are present both within the CVSWC and at or near the proposed
abutments and roadway conforms. These include areas of utility trench backfill, including the
considerable amount of fill placed and compacted atop the existing 54-inch diameter reclaimed
water line found within and parallel to the CVSWC centerline.
3.3.2.2 Alluvium (Qal)
The site is underlain by alluvium consisting of medium dense to dense silty sand (SM), sandy silt
(ML), and, at depth, fine to medium-grained sand with some gravel (SW) along with occasional,
thin layers or lenses of clayey silt (ML) and lean clay (CL).
3.3.3 Engineering Properties of Subsurface Soils
Based on our subsurface exploration, the project site at the locations of the exploratory borings
is underlain by mainly alluvium to the maximum explored depth of about 120 feet below existing
grade. About eight (8) feet of fill soils were encountered at the location of boring B-5.
The alluvium at the site consists of predominantly of spatially varying, interbedded layers of fine
sand (SP/SW) and silty fine sand (SM) with some gravel with little to no clay binder and silt (ML)
with fine sand and/or some clay. Thickness of these soil layers varies significantly, ranging from
as thin as one-foot or less to as thick as 15 to 20 feet or more.
Occasional, interbedded seams or relatively thin layers of lean clay (CL) and silty clay (CL-ML)
were also encountered at the boring locations, primarily at depths greater than 40 to 50 feet below
existing grade. A relatively thick zone (about 15 feet) of lean clay (CL) to silt with clay (ML) was
encountered at a relatively shallow depth of 12 feet below grade at the location of Boring B-4.
The above subsurface conditions are indicative of highly variable (both vertically and laterally)
subsurface soil conditions, likely associated with variable short-term or seasonal and long-term
water flow, sediment characteristics and depositional conditions within and along the channel.
The sand (SP/SW) and silty sand (SM) layers are generally medium dense to very dense with
moisture content and dry densities ranging mostly from about 2.5 to 6.0 percent, and 100 to 115
pcf, respectively. The silt (ML) soils are generally medium dense to dense and, when containing
some clay binders, medium stiff to stiff. The moisture content and the dry density of the silt (ML)
soils generally ranged from about 6.0 percent to about 15 to 20 percent and 100 pcf to 120 pcf,
respectively.
The clay (CL) and silty clay (CL-ML) soils at the site can be characterized as generally medium
stiff at shallow depths to stiff at deeper depths. The moisture content of these soils ranges mainly
from about 25 to 36 percent and dry densities ranges from mainly about 76 to 94 pcf.
Based on Atterberg Limit Tests, the Liquid Limit (LL) of the fine-grained soil samples (ML and CL)
tested ranged from about 27 to 42. The plasticity index of these soils ranged from about non-
plastic to 14.
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The above results indicate that site soils consisting of sand and silt contains little or no clay binders
or cohesion. Furthermore, the sand (SP/SW) and silty sand (SM) soils were relative dry at the
time of the field exploration.
The effective friction angle (’) of the two relatively coarse-grained soil samples subject to direct
shear testing ranged from about 34 to 36 degrees. A silt (SM) sample tested in direct shear
indicated an effective friction angle (’) 29 degrees. The cohesion of these samples ranged from
about 50 to 350 psf.
Based on one consolidation test the coefficient of compression of a clay (CL) sample tested was
measured to be about 0.18, which can be considered as relative high. That is, the fine-grained or
clay (CL) soils at the site are relatively compressible. Based on this result soils at the site are
considered normally consolidated.
One of the soil samples (B-4 @ 20’) was tested for chemical properties relevant to soil corrosion
potential. Based on this test, the sample exhibited the following chemical content properties:
PH = 5.2, and
Minimum Resistivity = 2,560 ohms-cm.
Sulfate = 334 ppm
Chloride = 672 ppm
4.0 SEISMIC HAZARD ANALYSIS
4.1 Faulting and Seismicity
Because much of southern California is located along the boundary between the Pacific and North
American tectonic plates, the region is susceptible to potentially strong seismic activity. Relative
to the North American Plate, the Pacific Plate is moving in a northwesterly direction at an
estimated rate of 50 millimeters per year. The main break, which marks the actual plate boundary,
occurs along the San Andreas Fault zone, which at its closest is approximately 5 miles from the
project site. Approximately 60%-70% of the movement between the Pacific and North American
Plates is accommodated by the San Andreas Fault. The remaining motion is distributed between
the Eastern Mojave Shear Zone and several sub-parallel faults of the San Andreas Fault,
including the San Jacinto, Whittier-Elsinore, Newport-Inglewood, Palos Verdes, and several
offshore faults.
In 2007-2008, a group of scientists referred to as the 2007 Working Group on California
Earthquake Probabilities (WGCEP, 2008) calculated that the southern San Andreas Fault had a
59 percent probability of causing an earthquake of at least magnitude 6.7 in the next 30 years.
That probability increases with each passing year without an earthquake.
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The nearest major seismic source or fault from the site is the San Andreas (Coachella) section of
the San Andreas Fault. It is comprised of a relatively straight, predominantly right-lateral strike
slip fault that extends from Bombay Beach in the Salton Sea northward to the Biskra Palms area
north of Indio, a distance of about 42 miles. The San Andreas (Coachella) section is the only
section of the southern San Andreas that has not produced a major earthquake in historic times
(Sieh and Williams, 1990). Paleoseismic studies indicate that the last surface-rupturing
earthquake on this segment occurred more than 320 years ago, around A.D 1680 (Sieh and
Williams, 1990).
4.2 Fault Rupture Hazard
The project site is not located within any of the State of California (CGS, 2015) designated Alquist-
Priolo Earthquake Fault Rupture (EFZ) zone.
As stated above the San Andreas (Coachella) section of the San Andreas Fault is the nearest
seismic source for the project site. Based on the Caltrans Online ARS Tool (Caltrans, 2015) for
seismic hazard analysis (Version 2.3.06) this strike slip fault is located about 8.2 km from the site
and capable of generating a maximum earthquake of moment magnitude, Mmax =7.9.
Based on the information, the project site is not considered susceptible to fault surface rupture
hazard.
4.3 Design Ground Motion or ARS Curve
The project site is located within a seismically active region of Southern California. The general
area has experienced strong earthquakes in the past and is likely to experience more moderate
to strong earthquakes during the design life of the project.
A deterministic, as well as a probabilistic seismic hazard analysis, was performed utilizing the
above referenced Caltrans Online ARS Tool (2015). Based on this analysis, probabilistic seismic
hazard corresponding to 1,000 year return period controls spectral acceleration for structure
periods. The resulting Acceleration Response Spectrum (ARS) for preliminary design is included
as Figure 3 in Appendix A.
4.4 Secondary Seismic Hazards
4.4.1 Soil Liquefaction Hazards
In the absence of groundwater within the maximum explored depth of about 120 feet, the project
site is not considered susceptible to soil liquefaction hazards during seismic shaking.
4.4.2 Additional Secondary Seismic Hazards
In the absence of soil liquefaction, the potential for other secondary seismic hazards, including
slope failure or lateral spreading and ground settlement, are considered low to very low for this
site.
Additional seismic analysis and evaluation will be performed during the preparation of the project
FR to further evaluate potential seismic hazards and, if necessary, to update design
recommendations.
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5.0 ADDITIONAL NATURAL HAZARDS
5.1 Flood Hazards
Bengal Engineering (2015) performed a detailed hydrology and hydraulic study of the existing
and proposed conditions at the project site. CVWD, which is the local agency responsible for the
regional flood control facilities (including the CVSWC), has established that the Standard Project
Flood (SPF), or design flow through the channel, is a discharge of 82,000 ft3/sec. The project will
convey the SPF of 82,000 ft3/sec with the required 1-foot of freeboard.
5.2 Scour Hazards
The potential for significant scour and associated hazards to the proposed structure exists at the
site. Bengal (2015) performed a detailed scour analysis as part of the project hydraulic/hydrology
study for the proposed improved channel and bridge support configurations. Results of this
analysis are summarized in Table 1 below.
As can be seen from the above results, the estimated scour depths vary depending on the
diameter of the bridge pier columns (pile extensions) located within the channel.
According to Caltrans guidelines, the total scour depth should be used for service loads and only
the long-term scour depth should be used for seismic loads. The above Caltrans scour guidelines
were followed for foundation design of the bridge.
The referenced Bengal (2015) hydrology and hydraulic reports suggests that concrete slope
revetments should be constructed under the bridge and at the three remaining corners of the
structure. The revetments are recommended to extend 300-feet beyond the bridge edges. The
toe of the revetments shall be set at elevation 26-feet under the bridge and extend both upstream
and downstream at a 0.2% slope.
5.3 Corrosion Hazards
Based on the results of chemical testing and Caltrans’ Corrosion Guidelines (Caltrans, 2003), site
soils are considered corrosive to structure elements due to a low pH (<5.5) and high chloride
content (>500 ppm). Therefore, appropriate corrosion protection measures should be
incorporated in the design of the structure elements.
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6.0 PRELIMINARY FOUNDATION RECOMMENDATIONS
6.1 General
Based on Caltrans’ current policy, foundations for the subject bridge should be designed in
accordance with the AASHTO Load and Resistance Factor (LRFD) Bridge Design Specifications,
Version 6 (AASHTO, 2012) as modified by the California Amendments (January, 2011).
6.2 Foundation Types
The proposed bridge will be a four (4)-span structure supported by two end supports or abutments
and three (3) intermediate or pier supports between the abutments, as shown in Figure 4 (Draft
General Plan) in Appendix A. The estimated preliminary foundations loads for each of the LRFD
Limit State are summarized Table 2 below.
Based on the foundation loads and site conditions, characterized by relatively low strength and
compressible foundation soils and site scour potential, deep foundations are recommended for
the proposed bridge structure.
Deep foundations may be either driven or drilled shafts. Due to the relatively high foundation loads
and pile-extension type columns, large diameter piles consisting of drilled shafts (i.e. Cast-in-
Drilled-Hole, or CIDH), pipe piles and Cast-in-Steel-Shell (CISS) piles are considered feasible for
the pier supports.
However, due the presence of interbedded layers of loose to medium dense, predominantly
cohesionless soils with some gravel and low moisture contents, the drilled holes required to install
CIDH piles are considered prone to soil caving hazards for this site. In general, the larger the
hole diameter and/or the depth, the higher the soil caving potential. Soil caving can result in
significant shaft construction difficulties and/or anomalies. While some shaft anomaly remediation
methods have been proposed and implemented during construction, it is difficult if not impossible
to completely remediate and/or verify the efficacy of such remediation. Occurrence of anomalies
results in not only construction difficulties and additional foundation cost but also compromised
design shaft capacities. Thus, every effort should be make in selecting the appropriate means
and methods to prevent any anomalies while constructing CIDH piles.
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Full depth temporary steel casing, carefully installed, emptied of soils, cleaned and withdrawn as
the concrete is poured within the casing, can be used to prevent CIDH hole instabilities, including
soil caving, during construction.
Alternatively, as stated above, driven pipe piles or Cast-in-Steel-Shell (CISS) piles may be
considered for this project to avoid the above difficulties. Additional advantages of driven piles
over CIDH piles are: (1) at the abutments such piles can be installed at a batter to provide
improved support to lateral loads, and (2) the total geotechnical nominal resistance in axial
compression of the as-built piles can be verified before field acceptance by means of quick and
cost-effective methods, such as the dynamic formula, wave equation and/or dynamic analysis,
without the need for time consuming and costly pile load tests. This results in a higher confidence
in the axial load carrying capacity of the as-built driven piles when compared to CIDH piles.
Therefore, whenever feasible, especially when the foundation at a support location consists of a
large diameter single pile and hence no foundation redundancy exists, driven piles should be
preferred over drilled shafts.
Based on the above considerations, Caltrans’ Standard Plan Class 200 piles consisting of open-
ended, 16-inch diameter and 1/2”-thick pipe piles (PP) are recommended for the abutments at
this site.
For piers, where demands are significantly higher and pile-extensions will be utilized as columns,
five-foot (5) diameter CISS piles are recommended. As stated above, CIDH piles may be
considered at the piers, provided full-depth temporary steel casings are used to support the holes
during excavation and installation of the reinforcement and concrete.
6.3 Preliminary Pile Lengths
Results of a preliminary analysis for pile geotechnical axial nominal resistance in compression for
both a 5-foot diameter CIDH pile and a 5-foot diameter CISS pile are presented in Figure 5 in
Appendix A. Based on these results, the preliminary estimated lengths of 5-foot diameter CISS
and CIDH piles for the pier supports is about 80 feet and 100 feet, respectively.
Results of a preliminary pile geotechnical axial compression capacity analysis for Class 200 (PP
16” x 1/2”) piles are presented in Figure 6 in Appendix A. Based on these results, to support a
design load of 200 kips per pile the estimated preliminary embedment length of the Class 200
(PP 16” x 1/2”) driven pile is about 52 feet.
6.4 Laterally Loaded Pile Design
The response of the proposed piles, including the required minimum or critical pile length, when
subjected to lateral loads may be evaluated based on a p-y type analysis. Recommend soil
parameters for such analysis using LPILE (Ensoft, Inc.) software are presented in Table 3 below.
Preliminary Foundation Report
Dune Palms Road Low Water Crossing at CVSWC Replacement Project
_______________________________________________________________________________________
______________________________________________________________________
Page -12- May 18, 2015
Table 3 - Idealized Soil Profile and Data for LPILE Analysis of a Single Pile/Shaft
Depth
(ft)
USCS
Soil
Type
Soil Type for
LPILE
Analysis
Effective
Unit
Weight
(pcf)
Cohesion/
Undrained
Shear
Strength
(psf)
Effective
Friction
Angle (º)
Modulus
Factor, k,
(lbs/in^3)
Strain
Factor
(50)
0-12 SM/ML Sand (Reese) 53 0.0 32 30 -
12-27 CL/ML Soft Clay
(Matlock) 33 750 0.0 - 0.01
27-37 SM/ML Sand (Reese) 58 0.0 34 50 -
37-44 SP Sand (Reese) 48 0.0 36 60 -
44-58 ML Sand (Reese) 53 0.0 34 50 -
58-80 SM/SP Sand (Reese) 53 0.0 36 60 -
80-120 SP Sand (Reese) 48 0.0 36 60 -
6.5 Lateral Earth Pressures
The project includes construction of the following earth retaining structures (ERS):
Abutments, and
Wing walls
For preliminary design, the following parameters for the structure backfill soils meeting the
material and compaction requirements specified in the Caltrans 2010 Standard Specification may
be used:
Total Unit Weight = 125 pcf
Effective Cohesion = 0.0 psf
Effective Friction Angle = 30 degrees
6.6 Foundation Settlement and Lateral Deflection
Based on Caltrans’ current foundation design requirements, and as specified in the MTD 3-1
(Caltrans, 2013) and MTD 4-1 (Caltrans, 2014), the permissible maximum support settlement for
the subject bridge under the service limit state load is 1.0 inch. The permissible lateral pile top
deflection under the service load is generally taken as ¼ inch. Detailed analysis for bridge support
settlements and the pile lateral deflections under the service loads will be performed once the
Type Selection is completed and updated foundation layout and loads are available. These results
will be presented in the project FR.
6.7 Drainage Considerations
The design of the abutment walls and the retaining structures should provide for adequate back
drains to prevent built up of excessive hydrostatic pressure in the backfill or retained soils.
Preliminary Foundation Report
Dune Palms Road Low Water Crossing at CVSWC Replacement Project
_______________________________________________________________________________________
______________________________________________________________________
Page -13- May 18, 2015
7.0 CONSTRUCTION CONSIDERATIONS
This section presents a preliminary discussion on the issues or considerations related to the
construction of the proposed facilities at this project site.
All construction activities should be performed in accordance with the applicable current federal
and State OSHA requirements.
It is our understanding that Dune Palms Road will need to be kept open to traffic at all times during
construction by means of a temporary at-grade crossing.
Unless specified otherwise herein or in the project plans and/or special provisions, all earthwork,
including the site preparation, excavation/cut, backfilling, approach roadway embankment fill
placement, and construction of the abutments, wing walls and foundation/piles, should be
performed in accordance with the current State of California, Department of Transportation,
Standard Specifications (Caltrans, 2010).
All earthwork, foundation installation and retaining wall construction should be performed under
the observation of and quality control or verification testing by a representative from the project
geotechnical firm.
All fills soils at the site should be placed in horizontal layers of uncompacted thickness of six (6)
to eight (8) inches, moisture conditioned within ±2.5 of the optimum water content and compacted
mechanically to at least 90% percent of the maximum dry density determined as per the ASTM
Standard D1557. Roadway subgrade, base and pavement materials should be compacted as
per the above referenced Caltrans’ 2010 standard specifications.
Imported fill soils, if any, should be cohesionless and well-graded in nature with less than 15%
fines content and PI<4. Structural backfill materials should meet the requirements specified in
the above referenced Caltrans’ 2010 Standard Specifications.
Groundwater was not encountered in borings at the time of our site exploration. However, surface
water, as well as perched groundwater and seepage, may be present at the site at any time of
the year. Some perched groundwater and seepage may be encountered in the excavations and/or
holes drilled at the site at any time of the year.
If CIDH piles are used, groundwater seepage and the potential for soil caving or sloughing of
sandy soil and gravel from the side of the holes, if not supported by temporary casing, should be
anticipated. The contractor shall be responsible for maintaining the stability of the hole at all times
during construction and obtaining a clean and firm condition at the bottom of the CIDH pile hole
prior to the placement of reinforcement and/or concrete.
To avoid reduction in the ground stability and shaft nominal resistance, the amount of time the
CIDH drill holes are kept open and/or unfilled with reinforcement and concrete should be
minimized. All open holes should be backfilled as completed shafts during the same work day.
No CIDH hole should be permitted to be left open overnight.
If driven piles are selected, an impact hammer shall be used to install the piles. Hard and/or
difficult driving conditions should be anticipated due to the presence of interbedded soil layers of
varying types/composition, and strength and stiffness, including thick layers of dense to very
dense sands with gravel.
Preliminary Foundation Report
Dune Palms Road Low Water Crossing at CVSWC Replacement Project
_______________________________________________________________________________________
______________________________________________________________________
Page -14- May 18, 2015
It is the contractor’s responsibility for selecting the appropriate driving hammer size and other
appurtenant equipment and driving details necessary to install the piles to the tip elevations
specified, and also to achieve the required total nominal resistance in axial compression,
whichever is deeper. The contractor should be required to evaluate and verify the feasibility of
the installation of the proposed driven piles by the driving equipment selected by performing a
Wave Equation Analysis. Results of this analysis shall be submitted to the owner for review and
concurrence prior to any pile driving at the support locations.
For acceptance, the total geotechnical nominal resistance in axial compression for driven piles
shall be verified as specified in the current Caltrans California Amendments to the LRFD BDS.
8.0 LIMITATIONS
Findings, recommendations and conclusions presented in this report are based on subsurface
exploration at isolated and limited locations. Subsurface conditions at other locations may differ
significantly. Findings and recommendations presented herein are preliminary in nature, subject
to change and should be used only for the Type Selection and/or the preliminary design. Further
review, interpretation and analysis are required to develop the final recommendations to be
presented in the project foundation report (FR), and used in the final analysis and design of the
proposed facilities and in the development of the project plans and specifications for construction.
Data, conclusions and recommendations contained in this report are solely for use by the City of
La Quinta and its’ designated consultants. They are applicable to the proposed project only.
Bengal Engineering, Inc. accepts no liability for use of the content of this report by others and/or
for other projects and purposes.
This preliminary foundation report was prepared in accordance with the generally accepted
geotechnical practices at this time in Southern California. We make no other warranty, either
implied for expressed.
We appreciate this opportunity to be of service to the City of La Quinta. If you have any questions
or we can be of any further assistance at this time, please do not hesitate to contact us.
Very truly yours,
BENGAL ENGINEERING, INC.
Preliminary Foundation Report
Dune Palms Road Low Water Crossing at CVSWC Replacement Project
________________________________________________________________________________________
May 18, 2015
-REFERENCES-
AASHTO (2012), AASHTO LRFD Bridge Design Specifications, 6th Edition, American Association
of State Highway and Transportation Officials, with CA Amendments (2014).
ASTM (2014), Annual Books of ASTM Standards, Vol. 04.08, Soils and Rock, American Society
of Testing and Materials, Philadelphia, Pennsylvania.
Bengal Engineering, Inc. (2015), Hydrology and Hydraulic Study for the Replacement of the Dune
Palms Low-Water Crossing at the Coachella Valley Stormwater Channel, dated January 15.
Caltrans (2015), ARS ONLINE (Version 2.3.06)
Caltrans (2013), Seismic Design Criteria (Version 1.7), California Department of Transportation,
Sacramento, California.
Caltrans (2013), Memo-to-Designers 3-1, Deep Foundations, Sacramento, California.
Caltrans (2014), Memo-to-Designers 4-1, Spread Footings, Sacramento, California.
Caltrans (2010), Standard Specifications, State of California, Department of Transportation.
Caltrans (2003), Corrosion Guidelines, Version 1.0, California Department of Transportation.
California Geological Survey (2012), Geologic Map of Quaternary Surficial Deposits in Southern
California, Palm Springs 30’ x 60’ Quadrangle, CGS Special Report 214, Plate 24, dated
December 2012.
CGS (2014), Alquist-Priolo Earthquake Fault Zones, California Geological Survey, accessed at
http://www.quake.ca.gov/gmaps/WH/regulatorymaps.htm, on October 24, 2014.
City of La Quinta (2013), 2035 La Quinta General Plan, Chapter IV – Environmental Hazards,
adopted February 19, 2013.
Dibblee, T.W., Jr. (2008), Geologic Map of the Palm Desert & Coachella 15 Minute Quadrangles,
Riverside County, California: Dibblee Geology Center Map #DF-373, Scale: 1:62,500.
Earth Consultants International, Inc. (2014), Technical Background Report to the Safety Element
of the General Plan for the City of Coachella, dated September 2014.
Earth Mechanics, Inc. (2010), Final Foundation Report, Adams Street Bridge over Whitewater
River, City of La Quinta, California, EMI Project No. 08-167, dated June 2, 2010.
USACE (1980), Whitewater River Basin Feasibility Report for Flood Control and Allied Purposes,
San Bernardino and Riverside Counties, California, Appendix 1 Hydrology, dated May 1980.
USGS (2014), 2008 Interactive Deaggregation (of Seismic Hazards), accessed at
http://geohazards.usgs.gov/deaggint/2008/ in January, 2015.
2007 Working Group on California Earthquake Probabilities (2008), The Uniform California
Earthquake Rupture Forecast, Version 2 (UCERF 2): USGS Open File Report 2007-1437, CGS
Special Report 203, SCEC Contribution #1138, Version 1.0.
Page 15
Preliminary Foundation Report
Dune Palms Low Water Crossing at CVSWC Replacement Project
May 18, 2015
APPENDIX A
FIGURES AND PLATES
Page 16
Page 17
Page 18
0.000.501.001.502.002.500.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00Spectral Acceleration (g)Period (sec)Figure 3. Recommended Preliminary ARS Curve for the Proposed Dune Palms Road Low Water Crossing BridgeStructure: Dune Palms Road Low Water Crossing Site Coordinates: Latitude = 33.7103o, Longitude = -116.278o(Vs)30= 300 m/secDesign ARS:Probabilistic Ground Motion Controls for All Periods, PGA =0.8g Nearest Major Seismic Source (Fault) = San Andreas (Coachella)Fault Type = SS, Distance Rrup= 8.2 km, Mmax = 7.9Recommended Design ARS (Damping = 5%)
Page 19
0
20
40
60
80
100
120
140
0 1000 2000 3000 4000 5000
5' Dia. CIDH - Required
Length = 100 ft
60" Dia CISS - Required
Length = 80 ft
Total Factored Nominal Resistance in Axial Compression (kips)Pile Length Below Existing Ground Surface (ft)
Figure 5. Preliminary 60"-Diameter CIDH and CISS Pile Lengths for the Proposed Dune Palms
Road Low Water Crossing Bridge Piers
Page 21
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
0.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0
Total Geotechnical Nominal Resistance in Axial Compression (kips)Pile Embedment Depth (ft.)Support Location(s): Abut 1 and Abut 5
Driven Class 200 (PP 16"x 0.5") Piles
Figure 6. Total Geotechnical Nomimal Resistance in Axial Compression vs. Pile Embedment
Depth for the Proposed Dune Palms Road Low Water Crossing Bridge Abutments.
Page 22
Preliminary Foundation Report
Dune Palms Low Water Crossing at CVSWC Replacement Project
May 18, 2015
APPENDIX B
RESULTS OF FIELD EXPLORATION
Page 23
Preliminary Foundation Report
Dune Palms Low Water Crossing at CVSWC Replacement Project
May 18, 2015
LOGS OF TEST BORINGS
Page 24
4-7-8
(15)
10-17-17
(34)
4-5-6
(11)
11-21-30
(51)
3-5-7
(12)
9-17-25
(42)
6-12-14
(26)
8-13-20
(33)
5-15-14
(29)
10-24-20
(44)
4-6-7
(13)
SPT
1
MC
2
SPT
3
MC
4
SPT
5
MC
6
SPT
7
MC
8
SPT
9
MC
10
SPT
11
Alluvium (Qal)
Fine-grained Silty Sand (SM) - light brown, medium dense,
slightly moist
same as above (SM)
Silt (ML) - olive brown, medium stiff, moist
Fine-grained Sand with Silt (SP/SM) - light brown, dense,
slightly moist
Sandy Silt (ML) - light olive brown, medium stiff, slightly
moist to moist
Fine-grained Silty Sand (SM) - light bronw, medium dense,
moist
same as above (SM)
Silt (ML) with laminated Clayey Silt (ML) in sampler tip -
brown to olive brown, medium stiff, moist
Fine-grained Silty Sand (SM), Sandy Silt (ML) and Silt (ML) -
light brown to brown, dense/stiff, moist, 4"-6" thick beds
Laminated Clayey Silt (ML) to Silty Clay (CL) - olive brown to
brown, stiff, moist
same as above, (ML) and (ML/CL), medium stiff, moist
3
2
7
7
17
10
2
8
27
13
13
118
132
129
105
120
104
29
40
NP
27
CONS
NP
13
NOTES Calibrated Auto Hammer and Drill Rod Used, 79.1% Energy Transfer
GROUND ELEVATION 44.3 ft NGVD 88
LOGGED BY E. Pongracz
DRILLING METHOD HSA - Track Rig CME 75
DRILLING CONTRACTOR 2R Drilling GROUND WATER LEVELS:
CHECKED BY
DATE STARTED 10/13/14 COMPLETED 10/13/14
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
HOLE SIZE 8" inches
(Continued Next Page)GRAPHICLOGBLOWCOUNTS(N VALUE)SAMPLE TYPENUMBERDEPTH(ft)0
10
20
30
40
50
60ELEV(ft)40
30
20
10
0
-10
MATERIAL DESCRIPTION
UNDRAINED SHRSTRENGTH (tsf)MOISTURECONTENT (%)DRY UNIT WT.(pcf)LIQUIDLIMITPLASTICLIMITATTERBERG
LIMITS
FINES CONTENT(%)OTHER TESTSPLASTICITYINDEXPAGE 1 OF 2
BORING NUMBER B-1
CLIENT City of La Quinta
PROJECT NUMBER
PROJECT NAME Dune Palms Road Low Water Crossing
PROJECT LOCATION Dune Palms Rd over CV Channel
BENGAL GEOTECH BH V5 - BENGAL MOD GINT STD US LAB 2-10-10.GDT - 5/21/15 23:07 - C:\PROGRAM FILES (X86)\GINT\PROJECTS\DUNE PALMS.GPJBengal Engineering
250 Big Sur Drive
Goleta CA 93117
Telephone: (805) 685-6511
Page 25
9-9-15
(24)
13-17-22
(39)
19-40-
50/5"
14-18-22
(40)
16-30-22
(52)
MC
12
SPT
13
MC
14
SPT
15
SPT
16
Clayey Silt (ML) - brown to olive brown, medium stiff, moist,
in sharp contact with Sand (SP) - light brown, dense, slightly
moist
Fine-to medium-grained Sand (SP), fine-grained Sand (SP)
and medium- to coarse-grained Sand with Gravel (SW) -
tan, dense, slightly moist, 3"-4" layers
Silt with some Clay (ML) and fine-grained Silty Sand (SM) -
olive brown to light brown, very stiff/dense, moist
Fine- to coarse-grained Sand (SW) with some Gravel - light
tan, very dense, slightly moist
Fine-grained Sand (SP) with tracel Silt and scattered
pebbles - light brown, very dense, slightly moist
Groundwater not encountered. Boring backfilled with native
materials.
Bottom of borehole at 101.5 feet.
29
3
8
1
3
94
116
111 CONSGRAPHICLOGBLOWCOUNTS(N VALUE)SAMPLE TYPENUMBERDEPTH(ft)60
70
80
90
100ELEV(ft)-20
-30
-40
-50
MATERIAL DESCRIPTION
UNDRAINED SHRSTRENGTH (tsf)MOISTURECONTENT (%)DRY UNIT WT.(pcf)LIQUIDLIMITPLASTICLIMITATTERBERG
LIMITS
FINES CONTENT(%)OTHER TESTSPLASTICITYINDEXPAGE 2 OF 2
BORING NUMBER B-1
CLIENT City of La Quinta
PROJECT NUMBER
PROJECT NAME Dune Palms Road Low Water Crossing
PROJECT LOCATION Dune Palms Rd over CV Channel
BENGAL GEOTECH BH V5 - BENGAL MOD GINT STD US LAB 2-10-10.GDT - 5/21/15 23:07 - C:\PROGRAM FILES (X86)\GINT\PROJECTS\DUNE PALMS.GPJBengal Engineering
250 Big Sur Drive
Goleta CA 93117
Telephone: (805) 685-6511
Page 26
6-7-7
(14)
9-17-24
(41)
6-9-11
(20)
6-11-15
(26)
3-5-6
(11)
12-17-23
(40)
5-7-9
(16)
13-18-32
(50)
5-8-11
(19)
8-14-17
(31)
AU
1
SPT
2
MC
3
SPT
4
MC
5
SPT
6
MC
7
SPT
8
MC
9
SPT
10
MC
11
Alluvium (Qal)
Fine- to medium-grained Sand with some Silt (SP-SM) - light
brown, slightly dense, dry, with laminated Silt (ML) in
sampler tip - light gray, medium stiff
Fine- to medium-grained Sand (SP) with some Silt - light
brown, medium dense, dry to slightly moist
Very fine-grained Sand with some Silt (SM) - light brown,
medium dense, slightly moist, contains 1.5" thick Sandy Silt
(ML) bed
Laminated Silt (ML) and fine-grained Silty Sand (SM) - olive
brown to brown, medium stiff/medium dense, moist, 4"-6"
thick beds
Clayey Silt (ML) - olive brown, slightly stiff, moist, occasional
orange mottling
Fine-grained Sand (SP) - light brown, medium dense, moist
Fine-grained Silty Sand (SM) and Sandy Silt (ML) - light
olive brown, medium dense/ medium stiff, moist
Fine- to medium-grained Sand (SP) with olive brown Clayey
Silt (ML) rip-up clasts - light gray, very dense, moist
Fine-grained Sand with some Silt (SP/SM) - light brown,
medium dense, moist with Silt (ML) in sampler tip
Laminated Clayey Silt (ML) to Silt with some Clay (ML) -
olive brown to brown to olive, stiff, very moist
1
1
2
23
19
4
10
12
4
32
114
76
100
106
91
R-Value
DS
NOTES Calibrated Auto Hammer and Drill Rod Used, 79.1% Energy Transfer
GROUND ELEVATION 44 ft NGVD 88
LOGGED BY E. Pongracz
DRILLING METHOD HSA - Track Rig CME 75
DRILLING CONTRACTOR 2R Drilling GROUND WATER LEVELS:
CHECKED BY
DATE STARTED 10/13/14 COMPLETED 10/13/14
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
HOLE SIZE 8" inches
(Continued Next Page)GRAPHICLOGBLOWCOUNTS(N VALUE)SAMPLE TYPENUMBERDEPTH(ft)0
10
20
30
40
50
60ELEV(ft)40
30
20
10
0
-10
MATERIAL DESCRIPTION
UNDRAINED SHRSTRENGTH (tsf)MOISTURECONTENT (%)DRY UNIT WT.(pcf)LIQUIDLIMITPLASTICLIMITATTERBERG
LIMITS
FINES CONTENT(%)OTHER TESTSPLASTICITYINDEXPAGE 1 OF 2
BORING NUMBER B-2
CLIENT City of La Quinta
PROJECT NUMBER
PROJECT NAME Dune Palms Road Low Water Crossing
PROJECT LOCATION Dune Palms Rd over CV Channel
BENGAL GEOTECH BH V5 - BENGAL MOD GINT STD US LAB 2-10-10.GDT - 5/21/15 23:07 - C:\PROGRAM FILES (X86)\GINT\PROJECTS\DUNE PALMS.GPJBengal Engineering
250 Big Sur Drive
Goleta CA 93117
Telephone: (805) 685-6511
Page 27
6-6-14
(20)
20-23-21
(44)
15-15-10
(25)
7-10-11
(21)
15-21-40
(61)
SPT
12
SPT
13
SPT
14
SPT
15
SPT
16
Fine-grained Sand (SP) with some Silt w/ 3" thick olive
brown, mottled Clayey Silt (ML) lens - medium dense, moist
to very moist
Gravelly Sand (SW) grading to fine- to medium-grained
Sand (SP/SW) - light gray, dense, moist
Fine-grained Silty Sand (SM) with 5" thick lens of Clayey Silt
(ML) - light brown to olive brown, medium dense/stiff, moist
Fine- to medium-grained Sand (SW) - light gray to light
brown, grading to medium- to coarse-grained Gravelly Sand
(SW) - dense, slightly moist to moist
Fine- to medium-grained Sand (SW) - light brown, very
dense, slightly moist
Groundwater not encountered. Boring backfilled with native
materials.
Bottom of borehole at 101.5 feet.
12
16
14
2
3
106GRAPHICLOGBLOWCOUNTS(N VALUE)SAMPLE TYPENUMBERDEPTH(ft)60
70
80
90
100ELEV(ft)-20
-30
-40
-50
MATERIAL DESCRIPTION
UNDRAINED SHRSTRENGTH (tsf)MOISTURECONTENT (%)DRY UNIT WT.(pcf)LIQUIDLIMITPLASTICLIMITATTERBERG
LIMITS
FINES CONTENT(%)OTHER TESTSPLASTICITYINDEXPAGE 2 OF 2
BORING NUMBER B-2
CLIENT City of La Quinta
PROJECT NUMBER
PROJECT NAME Dune Palms Road Low Water Crossing
PROJECT LOCATION Dune Palms Rd over CV Channel
BENGAL GEOTECH BH V5 - BENGAL MOD GINT STD US LAB 2-10-10.GDT - 5/21/15 23:07 - C:\PROGRAM FILES (X86)\GINT\PROJECTS\DUNE PALMS.GPJBengal Engineering
250 Big Sur Drive
Goleta CA 93117
Telephone: (805) 685-6511
Page 28
4-5-5
(10)
5-7-9
(16)
4-6-11
(17)
3-5-7
(12)
11-11-14
(25)
5-10-10
(20)
9-14-18
(32)
6-11-11
(22)
6-12-16
(28)
5-8-10
(18)
10-20-36
(56)
MC
1
SPT
2
MC
3
SPT
4
MC
5
SPT
6
MC
7
SPT
8
MC
9
SPT
10
MC
11
Alluvium (Qal)
Fine-grained Sand with some Silt (SP/SM) - light brown to
tan, slightly dense, slightly moist
same as above (SP/SM) - very thinly bedded
Interbedded fine-grained Sand (SP) and Silt (ML) - light
brown to brown, medium dense/medium stiff, slightly moist
to moist
Fine-grained Sand with Silt (SP/SM) with 5" thick Sandy Silt
(ML) bed - tan to light brown, slightly dense / medium stiff,
slightly moist to moist, laminated sands
Fine-grained Sand with Silt (SP) and fine-grained Silty Sand
(SM) - light brown, medium dense, moist
Fine-grained Sand with some Silt (SP) - tan, medium dense,
slightly moist, fainly laminated
Fine-grained Sand (SP) - tan, medium dense, moist
Fine- to medium-grained Sand (SP) with some Silt - light
brown, medium dense, moist, occasional rust orange
oxidation mottling
Silty Sand (SM) and Clayey fine-grained Sand (SC) - light
brown to olive brown, medium dense/medium stiff, moist
Fine- to medium-grained Sand (SW) with widely scattered
small gravel - light tan, medium dense, moist
Silt with Clay (ML) - olive brown, stiff, moist, mottled; grading
to Sandy Silt (ML) - light brown
5
1
12
6
7
2
4
3
6
5
30
110
97
106
101
104
93
SV
SV
NOTES Calibrated Auto Hammer and Drill Rod Used, 79.1% Energy Transfer
GROUND ELEVATION 53.1 ft NGVD 88
LOGGED BY E. Pongracz
DRILLING METHOD HSA - Track Rig CME 75
DRILLING CONTRACTOR 2R Drilling GROUND WATER LEVELS:
CHECKED BY
DATE STARTED 10/14/14 COMPLETED 10/14/14
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
HOLE SIZE 8" inches
(Continued Next Page)GRAPHICLOGBLOWCOUNTS(N VALUE)SAMPLE TYPENUMBERDEPTH(ft)0
10
20
30
40
50
60
70ELEV(ft)50
40
30
20
10
0
-10
MATERIAL DESCRIPTION
UNDRAINED SHRSTRENGTH (tsf)MOISTURECONTENT (%)DRY UNIT WT.(pcf)LIQUIDLIMITPLASTICLIMITATTERBERG
LIMITS
FINES CONTENT(%)OTHER TESTSPLASTICITYINDEXPAGE 1 OF 2
BORING NUMBER B-3
CLIENT City of La Quinta
PROJECT NUMBER
PROJECT NAME Dune Palms Road Low Water Crossing
PROJECT LOCATION Dune Palms Rd over CV Channel
BENGAL GEOTECH BH V5 - BENGAL MOD GINT STD US LAB 2-10-10.GDT - 5/21/15 23:07 - C:\PROGRAM FILES (X86)\GINT\PROJECTS\DUNE PALMS.GPJBengal Engineering
250 Big Sur Drive
Goleta CA 93117
Telephone: (805) 685-6511
Page 29
12-13-21
(34)
13-19-22
(41)
8-13-16
(29)
6-9-8
(17)
16-24-28
(52)
16-18-22
(40)
SPT
12
SPT
13
SPT
14
SPT
15
SPT
16
SPT
17
Fine- to medium-grained Sand (SP) with widely scatt., small
gravel - light brown to tan, dense, slightly moist
Medium- to fine-grained Sand (SP) - light gray, dense,
moist; 2" thick Silt (ML) in sampler tip
Interbedded Silt with some Clay (ML), Sandy Silt (ML),
Clayey, fine-grained Sand (SC) and fine- to medium-grained
Sand (SP) - olive brown to brown to light gray, medium
stiff/medium dense, moist
Clayey Silt (ML) to fine-grained Sand with Silt (SM) - olive
brown to light brown, medium stiff, moist
Fine-to medium-grained Sand with widely scattered gravel
(SW) - light brown, dense to very dense, slighly moist
same as above (SP/SW) with beds of Gravelly Sand (SW) -
dense, slightly moist to moist
Groundwater not encountered. Boring backfilled with native
materials.
Bottom of borehole at 121.5 feet.
3
4
15
25
3
3GRAPHICLOGBLOWCOUNTS(N VALUE)SAMPLE TYPENUMBERDEPTH(ft)70
80
90
100
110
120ELEV(ft)-20
-30
-40
-50
-60
MATERIAL DESCRIPTION
UNDRAINED SHRSTRENGTH (tsf)MOISTURECONTENT (%)DRY UNIT WT.(pcf)LIQUIDLIMITPLASTICLIMITATTERBERG
LIMITS
FINES CONTENT(%)OTHER TESTSPLASTICITYINDEXPAGE 2 OF 2
BORING NUMBER B-3
CLIENT City of La Quinta
PROJECT NUMBER
PROJECT NAME Dune Palms Road Low Water Crossing
PROJECT LOCATION Dune Palms Rd over CV Channel
BENGAL GEOTECH BH V5 - BENGAL MOD GINT STD US LAB 2-10-10.GDT - 5/21/15 23:07 - C:\PROGRAM FILES (X86)\GINT\PROJECTS\DUNE PALMS.GPJBengal Engineering
250 Big Sur Drive
Goleta CA 93117
Telephone: (805) 685-6511
Page 30
3-2-3
(5)
3-2-3
(5)
3-4-4
(8)
4-6-10
(16)
17-30-36
(66)
9-9-11
(20)
10-13-15
(28)
6-12-16
(28)
SPT
1
MC
2
SPT
3
MC
4
SPT
5
MC
6
SPT
7
MC
8
SPT
9
MC
10
SPT
11
Alluvium (Qal)
Sandy Silt (ML), Silt w/ Clay (ML) and fine-grained Sand with
Silt (SP/SM) - dark brown to light brown, slightly
dense/slightly stiff, moist, mottled with occasional rootlet
Fine-grained Sandy Silt and Silty Sand (ML/SM) - light olive
brown, medium stiff, moist
Silt with some Clay (ML) with 3" thick Silty Clay (CL) seam -
olive to olive brown, slighty stiff, very moist to wet
Silt with some Clay (ML) in sharp contact with fine-grained
Silt with some Sand (ML) - light brown to olive brown, slightly
stiff, very moist
Laminated Clayey Silt (ML) with 3" Silty Clay (CL) seam -
olive brown to brown, medium stiff, very moist
Fine-grained Silty Sand / Sandy Silt (SM/ML) - light olive
brown, medium dense / medium stiff, moist; in sharp contact
with olive brown Silt with Clay (ML)
Fine-grained Sandy Silt (ML/SM) in sharp contact with
fine-grained Sand with Silt (SP) - brown to light brown,
medium stiff, moist
Fine-grained Sand (SP) - light brown, dense, slightly moist
Sandy Silt (ML) in sharp contact with Clayey Silt (ML) - light
brown to brown and olive, medium stiff, slightly moist to
moist
Laminated Clayey Silt (ML) - olive brown, medium stiff, very
moist to wet
Fine-grained Silty Sand (SM) - light brown, medium dense,
moist; with 4" thick brown Silt bed or lens
30
3
37
28
36
10
22
5
34
18
112
92
35
42
23
28
SV
SV,
CHEM
SV,
HYD
SV
12
14
NOTES Calibrated Auto Hammer and Drill Rod Used, 79.1% Energy Transfer
GROUND ELEVATION 43.9 ft NGVD 88
LOGGED BY E. Pongracz
DRILLING METHOD HSA - Track Rig CME 75
DRILLING CONTRACTOR 2R Drilling GROUND WATER LEVELS:
CHECKED BY
DATE STARTED 10/14/14 COMPLETED 10/14/14
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
HOLE SIZE 8" inches
(Continued Next Page)GRAPHICLOGBLOWCOUNTS(N VALUE)SAMPLE TYPENUMBERDEPTH(ft)0
10
20
30
40
50
60
70ELEV(ft)40
30
20
10
0
-10
-20
MATERIAL DESCRIPTION
UNDRAINED SHRSTRENGTH (tsf)MOISTURECONTENT (%)DRY UNIT WT.(pcf)LIQUIDLIMITPLASTICLIMITATTERBERG
LIMITS
FINES CONTENT(%)OTHER TESTSPLASTICITYINDEXPAGE 1 OF 2
BORING NUMBER B-4
CLIENT City of La Quinta
PROJECT NUMBER
PROJECT NAME Dune Palms Road Low Water Crossing
PROJECT LOCATION Dune Palms Rd over CV Channel
BENGAL GEOTECH BH V5 - BENGAL MOD GINT STD US LAB 2-10-10.GDT - 5/21/15 23:08 - C:\PROGRAM FILES (X86)\GINT\PROJECTS\DUNE PALMS.GPJBengal Engineering
250 Big Sur Drive
Goleta CA 93117
Telephone: (805) 685-6511
Page 31
15-30-40
(70)
9-7-7
(14)
13-11-34
(45)
16-22-19
(41)
9-22-18
(40)
7-18-30
(48)
MC
12
SPT
13
MC
14
SPT
15
SPT
16
SPT
17
Fine- to coarse-grained Sand with scattered gravel (SW) -
light gray, very dense, slightly moist
Mottled Clayey Silt (ML) - olive brown, medium stiff, moist
Interbedded fine-grained Sand (SP), Silt with some Clay
(ML), and medium- to coarse-grained Sand with Gravel
(SW), medium stiff/medium dense, moist
Fine- to medium-grained Sand (SP/SW) with scattered
Gravel - tan, very dense, slightly moist
same as above (SP) - dense, moist
Silty Sand (SM) gradiing into 12" thick Sandy Silt (ML) in
sharp contact with fine-to medium-grained Sand (SW) with
scattered Gravel - orange brown to olive brown to light gray,
medium stiff to dense, moist
Groundwater not encountered. Boring backfilled with native
materials.
Bottom of borehole at 121.5 feet.
5
34
14
3
3
10
105
109
SVGRAPHICLOGBLOWCOUNTS(N VALUE)SAMPLE TYPENUMBERDEPTH(ft)70
80
90
100
110
120ELEV(ft)-30
-40
-50
-60
-70
MATERIAL DESCRIPTION
UNDRAINED SHRSTRENGTH (tsf)MOISTURECONTENT (%)DRY UNIT WT.(pcf)LIQUIDLIMITPLASTICLIMITATTERBERG
LIMITS
FINES CONTENT(%)OTHER TESTSPLASTICITYINDEXPAGE 2 OF 2
BORING NUMBER B-4
CLIENT City of La Quinta
PROJECT NUMBER
PROJECT NAME Dune Palms Road Low Water Crossing
PROJECT LOCATION Dune Palms Rd over CV Channel
BENGAL GEOTECH BH V5 - BENGAL MOD GINT STD US LAB 2-10-10.GDT - 5/21/15 23:08 - C:\PROGRAM FILES (X86)\GINT\PROJECTS\DUNE PALMS.GPJBengal Engineering
250 Big Sur Drive
Goleta CA 93117
Telephone: (805) 685-6511
Page 32
7-14-14
(28)
8-12-16
(28)
3-4-6
(10)
6-10-12
(22)
6-10-12
(22)
8-10-12
(22)
6-11-15
(26)
10-23-26
(49)
7-10-13
(23)
10-12-24
(36)
5-5-8
(13)
SPT
1
MC
2
SPT
3
MC
4
SPT
5
MC
6
SPT
7
MC
8
SPT
9
MC
10
SPT
11
Earth Fill (ef)
Fine-grained Silty Sand (SM/ML) - light brown, dense,
slightly moist, occasional bit of trash, poor recovery
Alluvium (Qal)
Fine-grained Sandy Silt (ML) and laminated Silt (ML) - light
brown to brown, medium stiff, slightly moist
Fine-grained Sand (SP) with some Silt - light brown to tan,
slightly dense, slightly moist
Fine-grained Sand (SP) in sharp contact with Silt (ML) with
some fine Sand - tan to olive/olive brown, medium
dense/medium stiff, slightly moist to moist
Fine-grained Sand (SP) with some Silt - tan, medium dense,
slightly moist
Fine- to medium-grained Sand (SP) - tan, medium dense,
slightly moist
same as above (SP)
Laminated Silt (ML) in sharp contact with fine-grained Sand
with little Silt (SP) - brown to olive brown to light tan, medium
stiff/medium dense, moist
Very fine-grained Silty Sand (SP/ML) grading to Sandy Silt
(ML) - light brown to brown, medium dense/medium stiff,
moist
Bedded Silt (ML) grading to Silty with some Clay (ML) and
very fine-grained Silty Sand (SM/ML) - light tan to
brown/olive brown, medium stiff/medium dense, slightly
moist to moist
Silt with some Clay (ML) - olive brown, medium stiff, moist,
mottled
4
15
8
8
2
2
2
6
6
18
29
102
109
116
105
94
27 NP
DS
DS
NP
NOTES Calibrated Auto Hammer and Drill Rod Used, 79.1% Energy Transfer
GROUND ELEVATION 46.3 ft NGVD 88
LOGGED BY E. Pongracz
DRILLING METHOD HSA - Track Rig CME 75
DRILLING CONTRACTOR 2R Drilling GROUND WATER LEVELS:
CHECKED BY
DATE STARTED 10/15/14 COMPLETED 10/15/14
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
HOLE SIZE 8" inches
(Continued Next Page)GRAPHICLOGBLOWCOUNTS(N VALUE)SAMPLE TYPENUMBERDEPTH(ft)0
10
20
30
40
50
60
70ELEV(ft)40
30
20
10
0
-10
-20
MATERIAL DESCRIPTION
UNDRAINED SHRSTRENGTH (tsf)MOISTURECONTENT (%)DRY UNIT WT.(pcf)LIQUIDLIMITPLASTICLIMITATTERBERG
LIMITS
FINES CONTENT(%)OTHER TESTSPLASTICITYINDEXPAGE 1 OF 2
BORING NUMBER B-5
CLIENT City of La Quinta
PROJECT NUMBER
PROJECT NAME Dune Palms Road Low Water Crossing
PROJECT LOCATION Dune Palms Rd over CV Channel
BENGAL GEOTECH BH V5 - BENGAL MOD GINT STD US LAB 2-10-10.GDT - 5/21/15 23:08 - C:\PROGRAM FILES (X86)\GINT\PROJECTS\DUNE PALMS.GPJBengal Engineering
250 Big Sur Drive
Goleta CA 93117
Telephone: (805) 685-6511
Page 33
18-42-
50/5"
18-22-28
(50)
24-22-29
(51)
10-16-18
(34)
10-16-18
(34)
15-29-35
(64)
MC
12
SPT
13
SPT
14
SPT
15
SPT
16
SPT
17
Fine- to medium-grained Sand (SP) - light tan to light gray,
very dense, slightly moist
Fine- to coarse-grained Sand (SW) with scattered small
Gravel - light tan, very dense, slightly moist
same as above (SW) and Sand with Gravel (SW) - light tan,
very dense, slightly moist
Fine-grained Sand (SP) - tan, dense, slightly moist
Medium- to fine-grained Sand (SP) with interbeds of coarser
Sand with Gravel (SW/GW) - light tan, very dense, slightly
moist
Medium- to coarse-grained Sand (SW) with scatterred, small
Gravel - light tan, very dense, slightly moist
Groundwater not encountered. Boring backfilled with native
materials.
Bottom of borehole at 121.5 feet.
5
34
29
5
6
7
111 DSGRAPHICLOGBLOWCOUNTS(N VALUE)SAMPLE TYPENUMBERDEPTH(ft)70
80
90
100
110
120ELEV(ft)-30
-40
-50
-60
-70
MATERIAL DESCRIPTION
UNDRAINED SHRSTRENGTH (tsf)MOISTURECONTENT (%)DRY UNIT WT.(pcf)LIQUIDLIMITPLASTICLIMITATTERBERG
LIMITS
FINES CONTENT(%)OTHER TESTSPLASTICITYINDEXPAGE 2 OF 2
BORING NUMBER B-5
CLIENT City of La Quinta
PROJECT NUMBER
PROJECT NAME Dune Palms Road Low Water Crossing
PROJECT LOCATION Dune Palms Rd over CV Channel
BENGAL GEOTECH BH V5 - BENGAL MOD GINT STD US LAB 2-10-10.GDT - 5/21/15 23:08 - C:\PROGRAM FILES (X86)\GINT\PROJECTS\DUNE PALMS.GPJBengal Engineering
250 Big Sur Drive
Goleta CA 93117
Telephone: (805) 685-6511
Page 34
Preliminary Foundation Report
Dune Palms Low Water Crossing at CVSWC Replacement Project
May 18, 2015
APPENDIX C
RESULTS OF LABORATORY TESTING
Page 35
MOISTURE & DENSITY M1468-001
(ASTM D1587, D2216, D2937, D3550)DUNE PALMS
Sample No.
Boring /
Trench No.Depth Gs
Degree of
Saturation
R-1 B-1 5 2.70 20.9
R-2 B-1 10 2.70 22.0
S-3 B-1 15 2.70 -
R-4 B-1 20 2.70 57.3
S-5 B-1 25A 2.70 -
S-6 B-1 25B 2.70 -
R-7 B-1 30 2.70 43.9
S-8 B-1 35 2.70 -
R-9 B-1 40 2.70 50.4
S-10 B-1 45 2.70 -
R-11 B-1 50 2.70 54.9
S-12 B-1 55 2.70 -
R-13 B-1 60 2.70 98.1
R-14 B-1 70 2.70 16.0
R-15 B-1 80 2.70 43.9
S-16 B-1 90 2.70 -
S-17 B-1 100 2.70 -
S-1 B-2 5 2.70 -
R-2 B-2 10 2.70 6.4
S-3 B-2 15 2.70 -
R-4 B-2 20 2.70 50.0
S-5 B-2 25 2.70 -
R-6 B-2 30 2.70 16.1
S-7 B-2 35 2.70 -
R-8 B-2 40 2.70 54.0
S-9 B-2 45 2.70 -
R-10 B-2 50 2.70 100*
S-11 B-2 60 2.70 -
R-12 B-2 70 2.70 75.3
S-13 B-2 80 2.70 -
S-14 B-2 90 2.70 -
S-15 B-2 100 2.70 -
R-1 B-3 5 2.70 23.5
S-2 B-3 10 2.70 -
R-3 B-3 15 2.70 43.1
S-4 B-3 20 2.70 -
R-5 B-3 25 2.70 33.0
S-6 B-3 30 2.70 -
R-7 B-3 35 2.70 17.2
S-8 B-3 40 2.70 -
R-9 B-3 45 2.70 26.8
S-10 B-3 50 2.70 -
R-11 B-3 60 2.70 97.8
S-12 B-3 70 2.70 -
S-13 B-3 80 2.70 -
S-14 B-3 90 2.70 -
S-15 B-3 100 2.70 -
S-16 B-3 110 2.70 -
S-17 B-3 120 2.70 -
S-1 B-4 5 2.70 -
Visual Classification
0 3.4
2.4
7.5
27.4
12.6
Water
Content
(%)
16.8
14.4
9.9
6.5
2.2
1.4
2.5
0.8
1.1
13.1
29.1
2.7
8.4
10.1
11.8
3.8
31.7
1.8
22.6
18.5
4.1
2.9
4.6
1.1
11.7
11.9
16.3
13.5
1.5
5.0
29.7
5.6
7.2
2.3
4.3
3.2
2.8
29.8
6.5
2.8
4.3
15.1
25.4
3.3
6.1
Wet Density
(pcf)
-
-
129.2
-
120.3
-
Dry Density
(pcf)
121.5 117.5
135.3 132.4
-
115.0 104.6
--
-
137.4 129.0
--
-
120.8 93.6
119.3 116.2
120.2
--
117.1 104.0
-
115.7 114.5
--
110.9
--
--
104.3 100.2
--
93.0 75.9
--
119.6 90.8
--
118.5 106.0
--
--
--
123.7 106.3
--
108.6 97.2
--
115.3 110.2
--
105.1 100.8
--
113.5 105.8
--
120.0 92.5
--
110.5 104.2
--
--
--
--
--
--
--
Page 36
MOISTURE & DENSITY M1468-001
(ASTM D1587, D2216, D2937, D3550)DUNE PALMS
Sample No.
Boring /
Trench No.Depth Gs
Degree of
Saturation
S-2 B-4 10 2.70 -
S-3 B-4 15 2.70 -
S-4 B-4 20 2.70 -
S-5 B-4 25 2.70 -
S-6 B-4 30 2.70 -
S-7 B-4 35 2.70 -
R-8A B-4 40 2.70 26.3
R-8B B-4 40 2.70 22.2
R-9 B-4 50 2.70 100*
S-10 B-4 60 2.70 -
R-11 B-4 70 2.70 23.6
S-12 B-4 80 2.70 -
R-13 B-4 90 2.70 72.2
S-14 B-4 100 2.70 -
S-15 B-4 110 2.70 -
S-16 B-4 120 2.70 -
S-1 B-5 5 2.70 -
R-2 B-5 10 2.70 64.3
S-3 B-5 15 2.70 -
R-4 B-5 20 2.70 38.6
S-5 B-5 25 2.70 -
R-6 B-5 30 2.70 12.3
S-7 B-5 35 2.70 -
R-8 B-5 40 2.70 26.1
S-9 B-5 45 2.70 -
R-10 B-5 50 2.70 61.1
S-11 B-5 60 2.70 -
R-12 B-5 70 2.70 28.0
S-13 B-5 80 2.70 -
S-14 B-5 90 2.70 -
S-15 B-5 100 2.70 -
S-16 B-5 110 2.70 -
S-17 B-5 120 2.70 -
x x x x x
x x x x x
x x x x x
x x x x x
x x x x x
x x x x x
x x x x x
x x x x x
x x x x x
x x x x x
x x x x x
x x x x x
x x x x x
x x x x x
x x x x x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
Visual Classification
Water
Content
(%)
3.2
36.7
28.4
36.2
10.1
22.4
4.9
34.1
14.4
3.1
3.0
4.9
33.7
17.8
5.3
7.8
1.8
2.0
2.2
10.4
4.2
15.5
8.0
5.3
34.1
28.6
4.6
5.9
6.1
18.1
29.1
x
x
x
x
6.1
7.3
x
x
x
x
x
x
x
x
x
x
x
--
Wet Density
(pcf)
Dry Density
(pcf)
--
--
117.4 111.8
123.2 92.1
--
--
110.8 105.6
--
--
--
110.4 104.8
--
--
125.2 109.4
118.0 102.2
--
--
--
118.7 116.3
--
117.4 108.9
--
110.5 93.6
--
111.0 104.8
--
--
--
117.4 111.5
--
x x
x x
--
--
x x
x x
x x
x x
x x
x x
x x
x x
x x
x x
x x
x x
x x
Page 37
Table C‐1: Summary of Atterberg Limit Tests
Sample Id. Soil Description Liquid Limit (LL)
(%)
Plastic Limit PL)
(%)
Plasticity Index
(PI)
B‐1/15’ Silt (ML) 29 Non‐plastic (NP) NP
B‐1/55’ Silt (ML) 40 27 13
B‐4/15’ Lean Clay (CL) 35 23 13
B‐4/50’ Silt (ML) 42 28 14
B‐5/60’ Silt (ML) 27 NP NP
Page 38
COARSE FINE COARSE MEDIUM FINE
Sample Depth
Classification
Project Description
GRAIN SIZE DISTRIBUTION
PLATE
B-4,S1
3" 1-1/2 1 3/4 1/2 3/8 4 8 10 16 20 30 40 50 60 100 200
GRAVEL SAND SILT OR CLAY
Dune Palms Road Low Water Crossing
Project No.
ML-SM
Description
Silt and Sity SAND10-11.5'B-4, Ring
0
10
20
30
40
50
60
70
80
90
100
0.001 0.010 0.100 1.000 10.000 100.000 PERCENT FINER BY WEIGHT GRAIN SIZE IN MILLIMETERS
U.S. STANDARD SIEVE SIZE
COARSE FINE COARSE MEDIUM FINE
Sample Depth
Classification
Project Description
GRAIN SIZE DISTRIBUTION
PLATE
B-4,S2
Project No.
ML
Description
Silt with Some Clay20-21.5'B-4, Ring
3" 1-1/2 1 3/4 1/2 3/8 4 8 10 16 20 30 40 50 60 100 200
GRAVEL SAND SILT OR CLAY
Dune Palms Road Low Water Crossing
0
10
20
30
40
50
60
70
80
90
100
0.001 0.010 0.100 1.000 10.000 100.000 PERCENT FINER BY WEIGHT GRAIN SIZE IN MILLIMETERS
U.S. STANDARD SIEVE SIZE
COARSE FINE COARSE MEDIUM FINE
Sample Depth
Classification
Project Description
GRAIN SIZE DISTRIBUTION
PLATE
B-4,S3
Project No.
ML-SM
Description
Silty Sand to Sandy Silt30-31.5'B-4, Ring
3" 1-1/2 1 3/4 1/2 3/8 4 8 10 16 20 30 40 50 60 100 200
GRAVEL SAND SILT OR CLAY
Dune Palms Road Low Water Crossing
0
10
20
30
40
50
60
70
80
90
100
0.001 0.010 0.100 1.000 10.000 100.000 PERCENT FINER BY WEIGHT GRAIN SIZE IN MILLIMETERS
U.S. STANDARD SIEVE SIZE
COARSE FINE COARSE MEDIUM FINE
Sample Depth
Classification
Project Description
GRAIN SIZE DISTRIBUTION
PLATE
B-3, S4
Project No.
ML-SM
Description
Silty Sand to Sandy Silt50B-3
3" 1-1/2 1 3/4 1/2 3/8 4 8 10 16 20 30 40 50 60 100 200
GRAVEL SAND SILT OR CLAY
Dune Palms Road Low Water Crossing
0
10
20
30
40
50
60
70
80
90
100
0.001 0.010 0.100 1.000 10.000 100.000 PERCENT FINER BY WEIGHT GRAIN SIZE IN MILLIMETERS
U.S. STANDARD SIEVE SIZE
COARSE FINE COARSE MEDIUM FINE
Sample Depth
Classification
Project Description
GRAIN SIZE DISTRIBUTION
PLATE
B-3, S4
3" 1-1/2 1 3/4 1/2 3/8 4 8 10 16 20 30 40 50 60 100 200
GRAVEL SAND SILT OR CLAY
Dune Palms Road Low Water Crossing
Project No.
ML-SM
Description
Silty Sand to Sandy Silt110B-4
0
10
20
30
40
50
60
70
80
90
100
0.001 0.010 0.100 1.000 10.000 100.000 PERCENT FINER BY WEIGHT GRAIN SIZE IN MILLIMETERS
U.S. STANDARD SIEVE SIZE
COARSE FINE COARSE MEDIUM FINE
Sample Depth
Classification
Project Description
GRAIN SIZE DISTRIBUTION
PLATE
B-3, S6
3" 1-1/2 1 3/4 1/2 3/8 4 8 10 16 20 30 40 50 60 100 200
GRAVEL SAND SILT OR CLAY
Dune Palms Road Low Water Crossing
Project No.
ML-SM
Description
Silty Sand to Sandy Silt20B-3
0
10
20
30
40
50
60
70
80
90
100
0.001 0.010 0.100 1.000 10.000 100.000 PERCENT FINER BY WEIGHT GRAIN SIZE IN MILLIMETERS
U.S. STANDARD SIEVE SIZE
COARSEFINECOARSEMEDIUM FINESILTCLAYSample NumberDepth (ft):Soil Type:Project Name:Project Number:Dune Palms Road Low Water CrossingCity of La QuintaParticle Size Distribution ReportML-CLGRAVELSANDFINESBoring/TP Number:B-4SPT25-26.50 20 40 60 80 100 0.001 0.010 0.100 1.000 10.000 100.000 Finer by Weight (%) Particle Size (mm) 3" 3/4" #4 #40 #200 #10
INTERNAL COHESION
FRICTION INTERCEPT
SAMPLE DESCRIPTION ANGLE(DEG.)(PSF)
B5@10 Brown Clayey Sand
Shear Strength at 36 54
0.2 inches of Deformation
SOUTHERN CALIFORNIA
SOIL & TESTING, INC.By:Date:3/26/2015
Job Number:
TBC
1412059
Matrix Geotechnical
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0Shear Stress (ksf)Confining Pressure (ksf)
Direct Shear Test Results
Shear Strength at 0.2 inches of
Deformation
Page 46
SOUTHERN CALIFORNIA
SOIL & TESTING, INC.By:Date:1/7/2015
Job Number:1412059
Shear Strength at 0.2 inches of Deformation 29 245
SAMPLE ID SAMPLE DESCRIPTION NOTES
B5@40 Brown F/M Silty Sand
TBC
INTERNAL
FRICTION ANGLE
(DEG.)
COHESION
INTERCEPT
(PSF)
Matrix Geotechnical
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0Shear Stress (ksf)Confining Pressure (ksf)
Direct Shear Test Results
Shear Strength at 0.2 inches
of Deformation
Page 47
INTERNAL COHESION
FRICTION INTERCEPT
SAMPLE DESCRIPTION ANGLE(DEG.)(PSF)
B5@70 Gray F-M Sand
Shear Strength at 34 348
0.2 inches of Deformation
SOUTHERN CALIFORNIA
SOIL & TESTING, INC.By:Date:12/30/2014
Job Number:
TBC
1412059
Matrix Geotechnical
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0Shear Stress (ksf)Confining Pressure (ksf)
Direct Shear Test Results
Shear Strength at 0.2 inches
of Deformation
Page 48
Page 1 of 1
Before After Liquid Limits:0 Test Date:
10.10 0.00 Plastic Limits:0
Dry Density (pcf):82.60 0.00 Plasticity Index (%):0
Saturation (%):34.00 0.00
Void Ratio:0.0000 0.0000 Specific Gravity:2.650 Assumed
Sample Description:Tan Silt
Project Number:Depth:Remarks:
Sample Number:B1@50 Boring Number:
Project:Matrix Geotechnical
Client:
Location:
Consolidation Test
Test Results
Moisture (%):
0.00
2.00
4.00
6.00
8.00
10.00
12.00
0.010 0.100 1.000 10.000 100.000Strain (%)Pressure (ksf)
Dune Palms Bridge
Bengal Engineering
La Quinta, California
50 feet
B-1
Page 49
Page 1 of 1
Before After Liquid Limits:0 Test Date:
23.70 Plastic Limits:0
Dry Density (pcf):101.80 Plasticity Index (%):0
Saturation (%):25.70
Void Ratio:Specific Gravity:2.650 Assumed
Sample Description:
Project Number:Depth:Remarks:
Sample Number:B1@80 Boring Number:
Project:Matrix Geotechnical
Client:
Location:
Consolidation Test
Test Results
Moisture (%):
0.00
1.00
2.00
3.00
4.00
0.010 0.100 1.000 10.000 100.000Strain (%)Pressure (ksf)
Dune Palms Bridge
Bengal Engineering
La Quinta, California
80 feet
B-1
Page 50
Table C‐2: Summary of R‐value Test
Sample Id. Soil Description R‐value
B‐2/0‐5’ Bulk Silty Sand (SM) 28
Table C‐3: Summary of Chemical Tests
Sample Id. Soil
Description pH
Minimum
Resistivity
(Ohm‐cm)
Chloride
Content (ppm)
Sulfate
Content (ppm)
B‐4/20’ Bulk Silt (ML) 5.2 2,560 672 337
Page 51