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SLADDEN ENGINEERING
Soil Engineers
PLAN CL.Ci<C NUMBER
PcN
Please use this Pim Ch&t !c Nan- heF (PCN) on
cozrespondence vj to 4ens use in plan check
6782 Stanton Ave., Suite E, Buena Park, CA 90621 • (562) 8 -1 �523.G952
39 -725 Garand Ln., Suite G, Pah-n Desert, CA 92211 • (760) 772 -3893
GEOTECHNICAL INVESTIGATION
TENTATIVE TRACT NO. 30125
SEC OF EISENHOWER DRIVE AND AVENUE 50
LA QUINTA, CALIFORNIA
- Prepared By -
Sladden Engineering
39 -725 Garand Lane, Suite G
Palm Desert, California 92211
(760) 772 -3893
_ Sladden Engineering
6782 Stanton Ave., Suite E, Buena Park;-CA 90621 (562) 864 -4121 (714) 523 -0952 Fax(714)523-1369
39 -725 Garand Ln., Suite G, Palm Desert, CA 92211 (760) 772 -3893 Fax(760)772-3895
March 14, 2001
Project No. 544 -1058
01 -03 -106
R. C. Hobbs Company
' 55 -487 Southern Hills
La Quinta, California 92253
' Attention: Mr. Roger Hobbs
Project: Tentative Tract No. 30125
' Eisenhower Drive and Avenue 50
La Quinta, California
' Subject: Geotechnical Investigation
Presented herewith is the report of our Geotechnical Investigation conducted at the site of the proposed
residential development located on the southeast corner of Eisenhower Drive and Avenue 50 along the La
' Quinta Resort Dunes golf course in the City of La Quinta, California. The investigation was performed in
order to provide recommendations for site preparation and to assist in foundation design for the proposed
residential structures and the related site improvements.
' This report presents the results of our field investigation and laboratory testing along with conclusions
and recommendations for foundation design and site preparation. This report completes our original
scope of services as understood.
We appreciate the opportunity to provide service to you on this project. If you have any questions
' regarding this report, please contact the undersigned
Respectfully submitted,
' SLADDEN ENGINEERING
OQ�oFESQ�
' Brett L. Ande on
Principal Engineer
CD No. C 45389
'
SER/pc Exp. 9 -30 -2002
sr CIVIL �P
�rIF F CAof�¢�
' Copies: 6 /R. C. Hobbs Company Y
'
GEOTECHNICAL INVESTIGATION
TENTATIVE TRACT NO. 30125
EISENHOWER DRIVE AND AVENUE 50
'
LA QUINTA, CALIFORNIA
'
March 14, 2001
TABLE OF CONTENTS
'
INTRODUCTION ........................................................................................ ...............................
1
SCOPEOF WORK ...................................................................................... ...............................
1
PROJECTDESCRIPTION ....................................:..................................... ...............................
1
'
SUBSURFACE CONDITIONS ................................................................... ...............................
2
CONCLUSIONS AND RECOMMENDATIONS ....................................... ...............................
2
FoundationDesign ................................................................................. ...............................
3
Settlements ............................................................................................. ...............................
3
'
LateralDesign ........... ..... -.....................................................................................................
4
RetainingWalls ...................................................................................... ...............................
4
'
Expansive Soils ...................................................................................... ...............................
ConcreteSlabs -on- Grade ............................:.......................................... ...............................
4
4
SolubleSulfates ..................................................................................... ...............................
4
'
Tentative Pavement Design ................................................................... ...............................
Shrinkage and Subsidence ..................................................................... ...............................
5
5
GeneralSite Grading .............................................................................. ...............................
5
'
1. Clearing and Grubbing ................................................................ ...............................
2. Preparation of Building and Foundation Areas ..........:................ ...............................
5
5
3. Preparation of Surfaces to Receive Compacted Fill .................... ...............................
6
4. Placement of Compacted Fill ...................................................... ...............................
6
'
5. Preparation of Slab and Paving Areas ......................................... ...............................
6
6. Testing and Inspection ................................................................. ...............................
6
GENERAL.................................................................................................... ...............................
7
APPENDIX A - Site Plan and Boring Logs
'
Field Exploration
APPENDIX B - Laboratory Testing
'
Laboratory Test Results
APPENDIX C - 1997 UBC Seismic Design Criteria
- Slodden Engineering ' . --
March 14, 2001
INTRODUCTION
Project No. 544 -1058
01 -03 -106
This report presents the results of our Geotechnical Investigation performed in order to provide
recommendations for site preparation and the design and construction of the foundations for the proposed
residential structures. The project site is located on the southeast corner of Eisenhower Drive and Avenue
50 along the La Quinta Resort Dunes golf course in the City of La Quinta, California. The preliminary
plans indicate that the proposed project will include 66 single family residences along with various
associated site improvements. The associated site improvements are expected to include paved roadways,
concrete driveways, walkways and patios, swimming pools, landscape areas and various underground
utilities.
SCOPE OF WORK
The purpose of our investigation was to determine certain engineering characteristics of the near surface
soils on the site in order to develop recommendations for foundation design and site preparation. Our
investigation included field exploration, laboratory testing, engineering analysis and the preparation of
this report. Evaluation of environmental issues or hazardous wastes was not within the scope of services
provided. Our investigation was performed in accordance with contemporary geotechnical engineering
principles and practice. We make no other warranty, either express or implied.
PROJECT DESCRIPTION
The project site is located on the southeast corner of Eisenhower Drive and Avenue 50 in the City of La
Quinta, California. The preliminary plans indicate that the project will include 66 single family
residences along with various associated site improvements. It is our understanding that the proposed
residential structures will be of relatively lightweight wood -frame construction and will be supported by
conventional shallow spread footings and concrete slabs on grade. The associated site improvements will
include paved roadways, concrete walkways, patios and driveways, swimming pools, landscape areas and
various underground utilities.
The majority of the project site is presently vacant but the ^ sou thwestern portion of the site is presently
being used as an employee parking lot for the nearby La Quinta Resort hotel. The subject site has been
cleared and leveled most likely during the initial development of the adjacent La Quinta Resort Dunes -
golf course. The southern portion of the site has been paved for use as a temporary parking lot for the La
Quinta Resort and Club located to the west across Eisenhower Drive. The twelfth and thirteen holes of
the Dunes course occupy the central and southwestern portions of the site. Three lakes exist along the
golf course and residential lots are proposed along the lakes. The northern channel embankment for the
La Quinta Evacuation Channel forms the south edge of the site. Eisenhower Drive and Avenue 50 are
paved adjacent to the site.
Based upon our previous experience with lightweight wood -frame structures, we expect that isolated
column loads will be less than 30 kips and wall loading will be less than to 3.0 kips per linear foot. A
grading plan prepared by MDS Consulting was utilized for our investigation. Grading is expected to
include relatively minor cuts and fills to match the nearby elevations and to construct slightly elevated
building pads to accommodate site drainage. This does not include removal and recompaction of the
foundation bearing soils within the building areas. If the anticipated foundation loading or site grading
varies substantially from that assumed; the recommendations included in this report should be
reevaluated.
Slodden Engineering
March 14, 2001 -2- Project No. 544 -1058
01 -03 -106
SUBSURFACE CONDITIONS
The near surface soils observed within our borings consist primarily of fine- grained silty sands and sandy
clayey silts. The soils within the upper 2 to 3 feet consisted primarily of sandy clayey silts but fine
grained silty sands were the most prominent soil type observed within our borings. The site soils were
fairly consistent in composition but somewhat inconsistent in stratigraphy within our borings. In general,
the site soils appeared somewhat loose throughout the depth of our borings but laboratory test results and
sampler penetration resistance (as measured by field blowcounts), suggest that the site soils become
somewhat firmer with depth. Relatively undisturbed samples indicated dry density varying from 83 to
107 pcf. The site soils were found to be somewhat dry throughout the upper portion of our borings but
the deeper silt layers were wet. Moisture content varying from 0.5 to 40.9 percent was determined for the
samples obtained.
Laboratory classification testing indicates that the near surface soils consist primarily of a somewhat
inconsistent combination of sandy clayey silts and very silty fine- grained sands. Expansion testing
indicates that the majority of the near surface soils are considered non- expansive and fall within the "very
low" expansion category in accordance with the Uniform Building Code classification system.
Consolidation testing indicates that the near surface sandy silts and silty sands are 'potentially
compressible and may be susceptible to hydroconsolidation and /or compression related settlements.
Groundwater was not encountered within our borings that extended to a maximum depth of
approximately 50 feet below the existing ground surface. Groundwater should not be a factor in
foundation design or construction.
CONCLUSIONS AND RECOMMENDATIONS
Based upon our field and laboratory investigation, it is our opinion that the proposed residential
-development is feasible from a soil mechanic's standpoint provided that the recommendations included in
this report are considered in building foundation design and site preparation. Due to the somewhat loose
and compressible conditions of the near surface soils,- remedial grading. including overexcavation and
recompaction is recommended for the proposed building areas. —We recbmmend that remedial grading
within the proposed building areas include overexcavation and recompaction of the primary foundation
bearing soils. Specific recommendations for site preparation are presented in the Site Grading section of
this report.
Groundwater was not encountered within our borings that extended to a depth of approximately 50 feet
below the existing ground surface. Due to the depth to groundwater, specific liquefaction analyses were
not performed. Based upon the depth to groundwater the potential for liquefaction and the related
surficial affects of liquefaction impacting the site are considered negligible.
The site is located within an active seismic area of Southern California within approximately 11.8
kilometers of the San Andreas Fault system. Strong ground motion resulting from earthquake activity
along the nearby San Andreas or San Jacinto fault systems is likely to impact the site during the
anticipated lifetime of the structure. Structures should be designed by professionals familiar with the
geologic and seismic setting of the site. As a minimum, structure design should conform to Uniform
Building Code (UBC) requirements for Seismic Zone 4. Pertinent seismic design criteria as outlined in
the 1997 UBC, is summarized in Appendix C of this report.
Slcdden Engineering
March 14, 2001 -3- Project No. 544 -1058
01-03-106
Caving did occur to varying degrees within each of our exploratory borings and the surface soils may be
susceptible to caving within deeper excavations. All excavations should be constructed in accordance
with the normal CalOSHA excavation criteria. On the basis of our observations of the materials
encountered, we anticipate that the subsoils will conform to those described by CalOSHA as Type B or C.
Soil conditions should be verified in the field by a "Competent person" employed by the Contractor.
The majority of the surface soils encountered during our investigation were found to be generally non -
expansive. Laboratory testing indicated an Expansion Index of 7 for the near surface sandy silts and 0 for
the silty sands, which correspond with the "very low" expansion category in accordance with UBC
Standard 18 -2. If imported soils are to be used during grading, they should have an Expansion Index of
less than 20.
The following recommendations present more detailed design criteria, which have been developed on the
basis of our field and laboratory investigation.
Foundation Design: The results of our investigation indicate that either conventional shallow
continuous footings or isolated pad footings, that are supported upon properly compacted soils,
may be expected to provide satisfactory support for the proposed residential structures.
Overexcavation and recompaction should be performed as described in the Site Grading Section
of this report.
Footings should extend at least 12 inches beneath lowest adjacent grade. Isolated square or
rectangular footings at least 2 feet square may be designed using an allowable bearing value of
1800 pounds per square foot. Continuous footings at least 12 inches wide may be designed using
an allowable bearing value of 1500 pounds per square foot. Allowable increases of 200 psf for
each additional 1 foot of width and 250 psf for each additional 6 inches of depth may be utilized
if desired. The maximum allowable bearing pressure should be 2500 psf. The allowable bearing
pressures are for dead and frequently applied live loads and may be increased by 1/3 to resist
wind, seismic or other transient loading.
Care should be taken to see that bearing soils are not.allowed to- become saturated from the
ponding of rainwater or irrigation. Drainage from the building areas should be rapid and
complete.
The recommendations made in the preceding paragraphs are based on the assumption that all
footings will be supported upon properly compacted soil. All grading shall be performed under
the testing and inspection of the Soils Engineer or his representative. Prior to the placement of
concrete, we recommend that the footing excavations be inspected in order to verify that they
extend into compacted soil and are free of loose and disturbed materials.
Settlements: Settlements may result from the anticipated foundation loads. These estimated
ultimate settlements are calculated to be a maximum of 1 inch when using the recommended
bearing values. As a practical matter, differential settlements between footings can be assumed as
one -half of the total settlement.
Slodden Engineering
March 14, 2001 -4- Project No. 544 -1058
01 -03 -106
Lateral Design: Resistance to lateral loads may be provided by a combination of friction acting
at the base of the slabs or foundations and passive earth pressure along the sides of the
foundations. A coefficient of friction of 0.42 between soil and concrete may be used with dead
load forces only. A passive earth pressure of 250 pounds per square foot, per foot of depth, may
be used for the sides of footings, which are poured against properly compacted native soils.
Passive earth pressure should be ignored within the upper 1 foot except where confined (such as
beneath a floor slab). When used in combination, either the passive resistance or the coefficient
of friction should be reduced by one - third.
Retaining Walls: Retaining walls may be required to accomplish the proposed construction.
Cantilever retaining walls may be designed using "active" pressures. Active pressures may be
estimated using an equivalent fluid weight of 35 pcf for native backfill soils with level free -
draining backfill conditions.
For walls that are restrained, "at rest" pressures should be utilized in design. At rest pressures
may be estimated using an equivalent fluid weight of 55 pcf for native backfill soils with level
free - draining backfill conditions.
Expansive Soils: Due to the prominence of non - expansive soils on the site, special expansive
soil design criteria should not be necessary for the design of foundations and concrete slabs -on-
grade. Because the mixing and blending associated with the recommended remedial grading may
change expansion potential, final design criteria should be established by the Structural Engineer
based upon post grading expansion test results.
Concrete Slabs -on- Grade: All surfaces to receive concrete slabs -on -grade should be underlain
by recompacted soils as described in the Site Grading Section of this report. Where slabs are to
receive moisture sensitive floor coverings or where dampness of the floor slab is not desired, we
recommend the use of an appropriate vapor barrier. Vapor barrieis should be protected by sand
in order to reduce the possibility of puncture and to aid in obtaining uniform concrete curing.
Reinforcement of slabs -on -grade in order to resist expansive soil pressures may not be required.
However, reinforcement will have a beneficial effect in containing cracking due to concrete
shrinkage. Temperature and shrinkage related cracking should be anticipated in all concrete
slabs -on- grade. Slab reinforcement and the spacing of control joints should be determined by the
Structural Engineer.
Soluble Sulfates: The soluble sulfate concentrations of the surface soils were determined to be
vary from 115 to 1,999 parts per million (ppm). The test results indicate soluble sulfate content
in excess of the usual allowable limits for the use of Type II cement and the use of Type V
cement or special sulfate resistant concrete mixes may be necessary. Appropriate concrete mix
designs should be established based upon post grading test results.
Slcdden Engineering
March 14, 2001 -5- Project No. 544 -1058
01 -03 -106
Tentative Pavement Design: All paving should be. underlain by .a. minimum compacted fill
thickness of 12 inches (excluding aggregate base). This may be performed as described in the
Site Grading Section of this report. The following preliminary pavement sections are based upon
a design R -Value of 50 and the recornmended pavement design section corresponds with the
typical minimum pavement section as determined by the City of La Quinta.
Onsite Roadways (Traffic Index= 6.0)
Use 3.0 inches of asphalt on 4'.5 inches of Class 2 base material
Aggregate base should conform to the requirements for Class 2 Aggregate base in Section 26 of
CalTrans Standard Specifications, January 1992. Asphaltic concrete should conform to Section
39 of the CalTrans Standard Specifications. The recommended sections should be provided with
a uniformly compacted subgrade and precise control of thickness and elevations during
placement.
Shrinkage and Subsidence: Volumetric shrinkage of the material, which is excavated and
replaced as controlled compacted fill should be anticipated. We estimate that this shrinkage
should vary from 20 to 25 percent. Subsidence of the surfaces which are scarified and compacted
should be between 0.2 and 0.3 tenths of a foot. This will vary depending upon the type of
equipment used, the moisture content of the soil at the time of grading and the actual degree of
compaction attained.
These values for shrinkage and subsidence are exclusive of losses, which will occur due to' tile
stripping of the organic material from the site, the removal of deleterious materials and the
removal of debris, trees and other subsurface obstructions.
General Site Grading: All grading should be performed in accordance with the grading
ordinance of the City of La Quinta, California. The following recommendations have been
developed on the basis of our field and laboratory testing:
- 1: Clearing --and Grubbing: Proper clearing of any existing — vegetation, debris,
foundations; -slabs, pavements and underground utilities -will- be-very- important. All
surfaces to receive compacted fill should be cleared of roots, vegetation, debris, and other
unsuitable materials that should be removed from the site. Soils that are disturbed due to
site clearing should be replaced as controlled compacted fill under the direction of the
Soils Engineer.
2. Preparation of Building and Foundation Areas: Building areas should be
overexcavated to a depth of at least 3 feet below existing grade or 3 feet below the
bottom of the footings, whichever is deeper. The exposed surface should be scarified,
moisture conditioned and compacted so that a minimum of 90 percent relative
compaction is attained. Once deleterious materials are removed, the native material may
be placed as controlled compacted fill. Overexcavation should be observed by a
representative of Sladden Engineering and compaction should be verified by testing.
Wet soils removed during excavation along the existing lakes should be dried back to
near optimum moisture content or mixed with dry soils prior to placement as engineered
fill material. The bottom of the excavations should be stable and unyielding prior to fill
placement. In wet areas that are expected along the existing lakes, additional
stabilization efforts may be necessary in isolated areas.
S116dden Engineering
March 14, 2001
-6-
Project No. 544 -1058
01 -03 -106
3: Preparation of Surfaces to Receive Compacted Fill: Other areas to receive compacted
fill should be brought to near optimum moisture content and compacted to a minimum of
90 percent relative compaction.
4. Placement of Compacted Fill: Fill materials consisting of on -site soils or approved
imported granular soils, should be spread in thin lifts, and compacted at near optimum
moisture content to a minimum of 90 percent relative compaction. Imported material
shall have an Expansion Index not exceeding 20. The contractor shall notify the Soils
Engineer at least 48 hours in advance of importing soils in order to provide sufficient
time for the proper evaluation of proposed import materials.
The contractor shall be responsible for delivering material to the site, which comply with
the project specifications. Approval by the Soils Engineer will be based upon material
delivered to the site and not the preliminary evaluation of import sources.
Our observations of the material encountered during our investigation indicate that
compaction will be most readily obtained by means of heavy rubber - wheeled equipment
and /or vibratory compactors.
5. Preparation of Slab and Paving Areas: All surfaces to receive asphalt concrete paving
or concrete slabs -on- grade, should be underlain by a minimum compacted fill thickness
of 12 inches. This may be accomplished by a combination of scarification and
recompaction of the surface soils and placement of the fill material as controlled
compacted fill. Compaction of the slab and pavement areas should be to a minimurn of
90 percent relative compaction.
6. Testing and Inspection: During grading tests and observations should be performed by
the Soils Engineer or his representative in order to verify that the grading is being
performed in accordance with the project specifications. Field density testing shall be
- -- performed in accordance with acceptable ASTM test methods-.-T-he-min imum acceptable
- - - &gree of compaction should be 90 percent of the maximum dry- density as obtained by.
the - ASTM D1557 -91 test method. Where testing indicates insufficient density,
additional- compactive effort shall be applied until retesting indicates satisfactory
compaction.
Siddden Engineering
March 14, 2001 -7- Project No. 544 -1058
01 -03 -106
GENERAL
The findings and recommendations presented in this report are based upon an interpolation of the soil
conditions between the exploratory boring locations and extrapolation of these conditions throughout the
proposed building area. Should conditions encountered during grading appear different than those
indicated in this report, this office should be notified.
This report is considered to be applicable for use by R. C. Hobbs Company for the specific site and
project described herein. The use of this report by other parties or for other projects is not authorized.
The recommendations of this report are contingent upon monitoring of the grading operation by a
representative of Sladden Engineering. All recommendations are considered to be tentative pending our
review of the grading operation and additional testing, if indicated. If others are employed to perform any
soil testing, this office should be notified prior to such testing in order to coordinate any required site
visits by our representative and to assure indemnification of Sladden Engineering.
We recommend that a pre job conference be held on the site prior to the initiation of site grading. The
purpose of this meeting will be to assure a complete understanding of the recommendations presented in
this report as they apply to the actual grading performed.
—Sladden Engineering
v
APPENDIX A
Site Plan
Boring Logs
APPENDIX A
FIELD EXPLORATION
For our field investigation, 8 exploratory borings were excavated on February 26 and March 2, 2001,
using a truck mounted hollow stem auger rig (Mobile B61) in the approximate locations indicated on the
site plan included in this appendix. Continuous logs of the materials encountered were prepared on the
site by a representative of Sladden Engineering. The boring logs are included in this appendix.
Representative undisturbed samples were obtained within our borings by driving a thin - walled steel
penetration sampler (California split spoon sampler) or a Standard Penetration Test (SPT) sampler with a
140 pound hammer dropping approximately 30 inches (ASTM D1586). The number of blows required to
drive the samplers 18 inches was recorded in 6 inch increments and blowcounts are indicated on the
boring logs.
The California samplers are 3.0 inches in diameter, carrying brass sample rings having inner diameters of
2.5 inches. The standard penetration samplers are 2.0 inches in diameter with an inner diameter of 1.5
inches. Undisturbed samples were removed from the sampler and placed in moisture sealed containers in
order to preserve the natural soil moisture content. Bulk samples were obtained from the excavation
spoils and samples were then transported to our laboratory for further observations and testing.
Y Slodden Engineering
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Boring Location Map
Proposed Residential.Development'
Tentative Tract 30125
Avenue 50 & Eisenhower'Drive
La Quinta, California
Sladden Engineering:_: °;.
DATE: 3 -19 -01 JOB NO.: 544` - 10.58-
MILES i AVENUE
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48th AVENUE
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54th AVENUE
Tentative Tract 30125
Eisenhower Drive &Avenue 50 / La Quinta, California
Date: 2 -26 -01 BorinLr
No. l Job No.: 544 -1058
o
�
DESCRIPTION
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REMARKS
A �
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U al
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Silty Sand: Brown,
SM
_
_
very silty, fine grained
_
5
5/5/10
Silty Sand: Brown,
SM
103
5.8
___
-
fine grained
io
4/5/7
99
3.1
---
15
7/7/10
Silty Sand: Brown,
SM
91
5.3
___
very silty, fine grained
20
5/5/5
91
5.3
79
25
7/7/10
Silty Clay: Brown
CL
97
18.3
- --
4/4/5
- --
40.9
- --
35
4/417
- --
31.6
40
5/5/5
- --
40.0
45
5/5/8
Sandy Silt: Brown,
ML'
___
10.5
___
-
very sandy
50
5/5/5
Silty Clay: Brown
CL
- --
28.2
-
Total Depth = 51.5'
'
-Recovered Sample
No Bedrock -
Note: The stratification lines
No Groundwater
55
If Standard Penetration
represent the approximate
boundaries between.the soil types;
-
-. -
Sample
the transitions may be gradual.
Tentative Tract 30125
Eisenhower Drive & Avenue 50 / La Quinta, California
Date: 3 -2 -01
Boring
No. 2 Job No.: 544 -1058
o
DESCRIPTION
q
0 0
REMARKS
A
ri
U M
M
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°
Silty Sand: Brown,
SM
_
very silty, fine grained
5
5/5/8
Sand: Grey brown,
SP /SM
95
2.0
- --
-
slightly silty, fine grained
10
4/5/7
Sandy Silt: Brown,
ML
83
2.0
- --
very sandy
15
8/10/15
Silty Clay: Brown
CL
90
22.7
- --
Total Depth = 16.5'
_
- Recovered Sample
No Bedrock
20
®Standard Penetration
No Groundwater
Sample
25
35
40
45
50
Note: The stratification lines
55
represent the approximate '
boundaries between the soil types;.
the transitions may be gradual.
Tentative Tract 30125
Eisenhower Drive &Avenue 50 / La Quinta, California
Date: 3 -2 -01
BorinLr
No. 4 Job No.: 544 -1058
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DESCRIPTION
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REMARKS
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_
Sandy Silt: Brown,
ML
_
very sandy
5
7/8/10
Clayey Silt: Brown,
ML
- --
6.0
- --
-
slightly sandy
10
5/5/7
Silty Sand: Brown,
SM
92
1.5
89
-
fine grained
15
_
5/5/5
Clayey Silt: Brown, sandy
ML
95
4.1
- --
20
Silty Sand: Brown,
SM
_
6/7/7
very silty, fine rained
94
3.5 '
82
_
Total Depth = 21.5'
-
-Recovered Sample
No Bedrock
®Disturbed Sample
No Groundwater
25
35
40
45
50
_
Note: The stratification lines
56
represent the approximate
boundaries between the soil types;
the transitions may be gradual.
Tentative Tract 30125
Eisenhower Drive & Avenue 50 / La Quinta, California
Date: 3 -2 -01
Borin
No. 5 Job No.: 544 -1058
�
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DESCRIPTION
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REMARKS
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Sandy Silt: Brown,
ML
very sandy
5
4/4/6
"
"
91
4.5
- --
10
5/8/8
Silty Sand: Brown,
SM
101
2.0
- --
fine grained
15
NM5/7/8
Silty Clay: Brown,
CL
96
19.1
-__
slightly sandy
20
Silty Sand: Brown,
SM
4/6/8
very silty, fine rained
93
6.0
Total Depth = 21.5'
- Recovered Sample
No Bedrock
"
No Groundwater
25
30
- --
-
- - -
35
40
45
A
50
_
Note: The stratification lines
55
represent the approximate
boundaries between the soil types;
-
the transitions may be gradual.
Tentative Tract 30125
Eisenhower Drive & Avenue 50 / La Quinta, California
Date: 3 -2 -01
Borine
No. 6 Job No.: 544 -1058
a�
> °
o
m
DESCRIPTION
q
REMARKS
4a `~
o�
A
�!
U
Pal
U)
,�
o U
0
_
Silty Sand: Brown,
SM
very silty, fine grained
5
7/8/8
96
2.0
- --
3/3/5
��
- -
.5
- --
15
4/5/5
Silty Sand: Brown,
SM
- --
2.0
- --
"
fine grained
20
5/5/8
Sil ty Clay: Brown
CL
9.3
Total Depth = 21.5'
- Recovered Sample
No Bedrock
-
No Groundwater
mStandard Penetration
-
Sample
30
-
— - --
-
- - --
--
35
40
45
50
.
Note: The stratification lines
55
represent the approximate
boundaries between the soil types;
the transitions may be gradual.
Tentative Tract 30125
Eisenhower Drive & Avenue 50 / La Quinta, California
Date: 3 -2 -01
BorinLY
No. 7 Job No.: 544 -1058
o
DESCRIPTION
��
REMARKS
�w
0
0
o
A
rn
U
W
0
CO
Q
q15
o
U
0
Silty Sand: Brown,
SM
_
very silty, fine grained
5
7/15/20
Silty Sand: Brown,
SM
99
0.5
- --
fine grained
10
5/10/10
Clayey Silt: Brown, sandy
ML
93
6.0
- --
15
8/10/13
Silty Sand: Brown,
SM
_ --
3.0
- --
-
fine grained
Total Depth = 16.5'
- Recovered Sample
No Bedrock
20
No Groundwater
Standard Penetration
Sample
25
30
-
- - -- - -
- -
35
40
45
50
Note: The stratification lines
55
represent the approximate
boundaries between the soil types;
the transitions may be gradual.
. Tentative Tract 30125
Eisenhower Drive & Avenue 50 / La Quinta, California
Date: 3 -2 -01
BorinLy
No. 8 Job No.: 544 -1058
o
w
0
DESCRIPTION
A
0
o
a
REMARKS
a
.
a
A
r%
U Pal
t°
U
� a
0
_
Silty Sand: Brown,
SM
very silty, fine grained
5
5/5/10
Sandy Silt: Brown,
ML
96
2.0
___
Interbedded slightly silty
_
very sandy
sand layer 4" thick
10
5/5/7
Clayey Silt: Brown,
ML
97
8.7
- --
Interbedded fine grained
-
slightly sandy
sand layer 3" thick
15
3/3/4
Silty Sand: Brown,
SM
-_-
5.3
- --
-
fine grained
20
3/4/5
Clayey Silt: Brown, sandy
ML
---
21.2
- --
Total Depth = 21.5'
- Recovered Sample
No Bedrock
No Groundwater
25
JU Standard Penetration
-
Sample
30
- - -
- -- -- -
- --
-- -
35
40
-
1
45
50
-
Note: The stratification lines
55
represent the approximate
boundaries between the soil types;
- -
the transitions may be gradual. .
APPENDIX B
LABORATORY TESTING
Representative bulk and relatively undisturbed soil samples were obtained in the field and returned to our
laboratory for additional observations and testing. Laboratory testing was generally performed in two
phases. The first phase consisted of testing in order to determine the compaction of the existing natural
soil and the general engineering classifications of the soils underlying the site. This testing was
performed in order to estimate the engineering characteristics of the soil and to serve as a basis for
selecting samples for the second phase of testing. The second phase consisted of soil mechanics testing.
This testing including consolidation, shear strength and expansion testing was performed in order to
provide a means of developing specific design recommendations based on the mechanical properties of
the soil.
CLASSIFICATION AND COMPACTION TESTING
Unit Weight and Moisture Content Determinations: Each undisturbed sample was weighed and
measured in order to determine its unit weight. A small portion of each sample was then subjected to
testing in order to determine its moisture content. This was used in order to determine the dry density of
the soil in its natural condition. The results of this testing are shown on the Boring Logs.
Maximum Density - Optimum Moisture Determinations: Representative soil types were selected for
maximum density determinations. This testing was performed in accordance with the ASTM Standard
D1557 -91, Test Method A. The results of this testing are presented graphically in this appendix. The
maximum densities are compared to the field densities of the soil in order to determine the existing
relative compaction to the soil. This is shown on the Boring Logs, and is useful in estimating the strength
and compressibility of the soil:.
Classification Testing: Soil samples were selected for classification testing. This testing consists of
mechanical grain size analyses and Atterberg Limits determinations. These provide information for
.developing classifications for the soil in accordance with the Unified Classification System. This
classification system categorizes the soil into groups having similar engineering characteristics. The
results of this testing are -very useful in detecting variations in the soils and-in selecting samples for
further testing. - - -
SOIL MECHANIC'S TESTING
Direct Shear Testing: Two bulk samples were selected for Direct Shear Testing. This testing measures
the shear strength of the soil under various normal pressures and is used in developing parameters for
foundation design and lateral design. Testing was performed using recompacted test specimens, which
were saturated prior to testing. Testing was performed using a strain controlled test apparatus with
normal pressures ranging from 800 to 2300 pounds per square foot.
Expansion Testing: Two bulk samples were selected for Expansion testing. Expansion testing was
performed in accordance with the UBC Standard 18 -2. This testing consists of remolding 4 -inch diameter
by 1 -inch thick test specimens to a moisture content and dry density corresponding to approximately 50
percent saturation. The samples are subjected to a surcharge of 144 pounds per square foot and allowed
to reach equilibrium. At that point the specimens are inundated with distilled water. The linear
expansion is then measured until complete.
Consolidation Testing: Six relatively undisturbed samples were selected for consolidation testing. For
this testing one -inch thick test specimens are subjected to vertical loads varying from 575 psf to 11520 psf
applied progressively. The consolidation at each load increment was recorded prior to placement of each
subsequent load. The specimens were saturated at the 575 psf or 720 psf load increment.
Slodden Engineering
Job No.: 544 -1058
100 ' I I I
9 10 11 12 13 14
Moisture Content ( %)
a
METHOD OF COMPACTION
ASTM D- 1557 -91, METHOD A OR C
BORING MAXIMUM UNIT WEIGHT OPTIMUM MOISTURE CONTENT
2 @0 -5' 103 11.4
MAXIMUM DENSITY - OPTIMUM MOISTURE CURVE
I
116
115
¢ 114
C
d
A
113
A
112
111 4-
10
11 12 13
Moisture Content ( %)
METHOD OF COMPACTION
ASTM D- 1557 -91, METHOD A OR C
BORING MAXIMUM UNIT WEIGHT
3 @1 -5' 115
Job No.: 544 -1058
14 15
OPTIMUM MOISTURE CONTENT
12.4
MAXIMUM DENSITY - OPTIMUM MOISTURE CURVE
U-- -
DIRECT SHEAR TEST
1.8
1.6
1.4
1.2
1.0
.8
.6
I �
,
.4
.2
00
.2
.4 .6
.8 1.0 1.2
1.4 1.6 1.8
0 = 30°
c 150 psf
where 0 =
Shear Angle
c =
Cohesion
Boring 2 @0 -5'
Proposed Residential Development
Tentative Tract 30125
Avenue 50 & Eisenhower Drive
La Quinta, California
Sladden Engineering
DATE: 3 -18 -01 JOB NO.: 544 -1058
I �
,
1.8
1.6
1.4
1.2
1.0
.8
.6
.4
.2
1
1
DIRECT SHEAR TEST
.2 .4 .6 .8 1.0 1.2 1.4 1.6 1.8
0 =28°
c = 200 psf
where 0 =Shear Angle
c = Cohesion
Boring 3 @ 1 - 5'
Proposed Residential Development
Tentative Tract 30125
Avenue 50 & Eisenhower Drive
La Quinta, California
Sladden Engineering
DATE: 3 -18 -01 JOB NO.: 544 -1058
I
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1
.2 .4 .6 .8 1.0 1.2 1.4 1.6 1.8
0 =28°
c = 200 psf
where 0 =Shear Angle
c = Cohesion
Boring 3 @ 1 - 5'
Proposed Residential Development
Tentative Tract 30125
Avenue 50 & Eisenhower Drive
La Quinta, California
Sladden Engineering
DATE: 3 -18 -01 JOB NO.: 544 -1058
Pressure in KIPS per Square Foot
0.000
0.720 2.880
5.760
z
z
0.0
ffec�c@iul
IT-Ti
z )EMer Z4=
L
.01
z Z-
.02
577
Rebound
.03
z
Cd
.04
+
z
a.
.05—�
.06
0
.0
z z z
z
7 z
z
z z
+
z
o
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CD
0
7-
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.08
z z
z
z
7:
z
..09
z
Z
0.1
Z z
z
7 z!=
z z
.12
z z
t
Z
.13
rive & Avenue 50 La Quinta
Eisenhower Eis hower Drive
Consolidation Diagram
1 @ 5'
EDate:3/18/01
10
SLADDEN ENGINEERING
lJob No.: 544-1058
`
Pressure in KIPS per Square Foot
0.000
0.720
2.880
5.760
E Eisenhower Drive & Avenue 50 La Quinta
isenhower Dr,
Consolidation Diagram
B 13
EDate:3/18/01
SLADDEN ENGINEERING
11 /01 -1058
0.=
I Job No.: 544 =j
Pressure in KIPS per Square Foot
0.000
.575 2.300
4.600
0.0
Z
Effec--t=5f:Addi-7p—g
F
-W-a-t e f:
Z
.01
.02
Z Z
z
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z ==�z
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.08
z
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z z
z
0.1
z
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z z
z
.12
z
Z
.13
Z I
Eisenhower Drive & Avenue 50 La Quinta
E' senhower Dr
Consolidation Diagram
Boring 3 @ 10'
EDate:3/18/01
I
SLADDEN ENGINEERING
1"05
rJob No.: 54J48
t /I /Oj -1058
Pressure in KIPS per Square Foot
0.000
.575 2.300
4.600
0.0
=F-- z
I [Z
Z:
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z z
z
er-
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z
z
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.02
z
-Z -Z
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z =�Rebotffi-d
'z
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c
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+
z
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:7 x
z
z 7:
z
z
0
0
.07
0
Z.
:1
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z
z
z
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.08
z z
Z 7
z z
.09
z
z
0.1
==4z z
z�
z
74=
z z z z
z
7 1 -
7w
.12
z 7 Z
Z:
Z: z
.13
7:
z
z
z z
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Eisenhower Drive & Avenue 50 La Quinta
E s hower Dn
Consolidation Diagram
Boring 3 @ 15'
EDate:3/18101
SLADDEN ENGINEERING
11 101 I Job No.: 544 -1058
0.0
.01
0.000
z
z 7z
z
Pressure in KIPS per Square Foot
.575 2.300
E ffia5f Add ng z
z =lWa t er
- \S
4.600
z
Z
Z
.02
:m
7.
z
.03
z
z
.04
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z
z
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.05
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L
.06
41
z q= Z
o
.07
z z
-- - — - ----------- - -
z I
z
.08
-Z
z
..09
0.1
z
.12
z
z =--EEr Z:
z
.13
7- z
z
7
Z
7 7
7 7
Eisenhower Drive & Avenue 50 La Quinta
Ei s hower Dr
Consolidation Diagram
Boring 7 @ 10'
EDate:3/18/011
SLADDEN ENGINEERING
I
Job No.: 544 -1058
0.0
.0,
.02
0.000
z
z Z
- - -
- - - - -- --------------
77=
Pressure in KIPS per Square Foot
.575 2.300
z —
7-
- - - - - - -
:E z
z
X Z:�
z
Effdd�— Ad 9-
4.600
z z
Z
7
7
.03
R-el�otihd=�
.04
z
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— - — - — - — -
z
i
9
.06
z z
co
o
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U)
0
.08
z- — -
— - —
-
z
z z
z
.09
0.1
z
--L: z
z
Z:
.12
I
Z
z:
.13
— - — - — - — -
c z z
E Eisenhower Drive & Avenue 50 La Quinta
i senhower Dr
Consolidation Diagram
Boring 8 @ 5'
EDate:3/18/01rJob
L
S SLADDEN ENGINEERING
t . -1058
. 11 /03 No.: 544
I I
Project No.: 544 -1058 R A IN'
S I Z E, M M
ACCUMULATION CURVE
F I N E COARSE DATE :
CLAY . }. SILT S AND--�—SANDVI GRAVEL
I US STANDARD SIEVES -
ON Y n V N V 7
Rnrincr t rnl S� 0 0 0 0 0 0
0, IC
Z 9
I e
V) 7
Q
a a
W 3
2
W I
a
PARTICLE SIZE, MM
l
CLAY-- = -- SILT E I N E COARSE
SAND --�-- SAND- -- GRAVEL
US STANDARD S.I E V ES --•
N iV Q e V �j Z Z2
Q
Boring 10' v 0 0 0 p. u ry
g Z z z 7 7 7 7-
Q$
O CS 0 0
PARTICLE 517-E, MM
Slodden Engineering
Project No.: 544 -1058 GRAIN S I 'Z E, M M
ACCUMULATION CURVE
F I NE COARSE D.�TE
—CLAY SILT SAND
_ • SAND S— IEGRAVEL-
US VES-
STANDARD
N$ n 0 0 z
Rnrma ?nn N
0 0 0 0 0 n 0 6 - z?
0 IC
Z G
� a
7
Q
a a
Z
W 3
w 2
W I
E
PARTICLE SIZE, MM
• MIN W,/ lslimiSmo11mimill
mllmm:,FA iniimlmmmiimlm.ol
MEN
• EmsI��I����I����I�I��
• ���1� ■ �INS lislimimmo1 =lMlIll
• IOS�11�11�1���1
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• • • • • • • • • • • • • • •
PARTICLE SIZE, MM
Slodden Engineering
�• E
Ell o
on
ME
PARTICLE SIZE, MM
Slodden Engineering
ANAHEIM TEST LABORATORY
3008 S. ORANGE AVENUE
SANTA ANA. CALIFORNIA 92707
PHONE (714) 549 -7267
TO SLADDFN ENGINE.ERTNG:
6782 STANTON-AVE. SUITE R
BUFNA PARK; CA. 9.0621
ATTN: BRETT ANDERSON
PROJECT: # 544 -1058
F.TSENNOWER A AVE. 50.
ANALYTICAL REPORT
SOLUBLE SULFATES
per CA_ 417,
N1
r3ULK
-H -2
- @"
0 -5'
115
ppm
M2
HULK
11 -3
@
1 -5'
1,999
ppm
DATE: 3/13/01
DO. No VERBAL
tShipoet No.
Lab No B 8010 1- 2
Soecilicclion.
Malei-ol.. SOIL
CTFULI' SUS TIED
rl �i
p.2
APPENDIX C
1997 UBC Seismic Design Criteria
Stcdden Engineering
1997 UNIFORM BUILDING CODE INFORMATION
The International Conference of Building Officials 1997 Uniform Building Code contains substantial
revisions and additions to the earthquake engineering section summarized in Chapter 16. Concepts
contained in the 1997 code that will likely be relevant to construction of the proposed residential
structures are summarized below.
Ground shaking is expected to be the primary hazard most likely to affect the site, based upon proximity
to significant faults capable of generating large earthquakes. Major fault zones considered to be most
likely to create strong ground shaking at the site are listed below.
Based on our field observations and understanding of local geologic conditions, the soil profile type
judged applicable to this site is S ►�, generally described as stiff or dense soil. The site is located within
UBC Seismic Zone 4. The following table presents additional coefficients and factors relevant to seismic
mitigation for new construction upon adoption of the 1997 code.
r
Slcdden Engineering
Fault Zone
Approximate Distance
From Site
Fault Type
1997 UBC
San Andreas
12 km
A
I
San Jacinto
30 km
A
Near - Source
Near - Source
Seismic
Seismic
Seismic
Acceleration
•Velocity
.Coefficient
Coefficient
Source
Factor, Na
Factor, N,.
Ca
C„
San Andreas
1.0
1.15
0.44 Na
0.64 N„
San Jacinto
1.0
1.0
0.44 N�
0.64 N,,