0005-132 (CSST) Geotechnical Investigation1
.
R
GEOTECHNICAL INVESTIGATION
'
PROPOSED MINI 'MART AND GAS STATION
6
HIGHWAY I I I AND DUNE PALMS ROAD
'
LA QUINTA, CALIFORNIA
1
'
- Prepared By -
Sladden Engineering
'
39-725 GARAND LN., SUITE G
PALM DESERT, CA 92211
(760) 772-3893
'
Slodden Engineering
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
' February 25, 2000 Project No. 544-0006
00-02-075
1
USA Petroleum Corporation'
30101 Agoura Court, Suite 200
' Agoura Hills, California -
'Attention: Mr. Mark McIlvain
tProject: Proposed Mini Mart and Gas Station
Highway 111 and Dune Palms Road
' La Quinta, California
Subject: Geotechnical Investigation
~' Presented herewith is the report of our Geotechnical Investigation conducted at the site of the proposed
mini mart and gas station facility to be located on the northwest corner of Highway 111 and Dune Palms
Road within the La Quinta Corporate Center commercial development 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 development.
' This report presents the results of our field investigation and laboratory testing along with conclusions
a'nd recommendations for foundation design and site preparation. This report completes our original
scope of services as described in our proposal dated January 12, 2000.
' 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
A `Pl
' Mson ��' �O
Principal Engineer CO No. C 48389 z JAI
Exp. 9-30-2002
FCAI
SER/pc
' Copies: 6/USA Petroleum Corporation
GEOTECHNICAL INVESTIGATION
PROPOSED MINI MART AND GAS STATION
HIGHWAY 111 AND DUNE PALMS ROAD
LA QUINTA, CALIFORNIA
February 25, 2000
TABLE OF CONTENTS
INTRODUCTION.................. :.................................................................................................... 1
SCOPEOF WORK..................................................................................................................... 1
PROJECTDESCRIPTION......................................................................................................... 1
SUBSURFACE CONDITIONS.................................................................................................. 2
CONCLUSIONS AND RECOMMENDATIONS...................................................................... 2
FoundationDesign................................................................................................................ 3
Settlements'............................................................................................................................ 3
LateralDesign....................................................................................................................... 3
RetainingWalls..................................................................................................................... 4
ExpansiveSoils..................................................................................................................... 4
ConcreteSlabs-on-Grade...................................................................................................... 4
SolubleSulfates .................. .......................... ....:.................. ................. ................................ 4
TentativePavement Design.................................................................................................. 4
Shrinkageand Subsidence.................................................................................................... 5
GeneralSite Grading............................................................................................................. 5
1. Clearing and Grubbing............................................................................................... 5
2. Preparation of Building Areas.................................................................................... 5
3. Preparation of Surfaces to Receive Compacted Fill ................................................... 5
4. Placement of Compacted Fill..................................................................................... 5
5. Preparation of Slab and Pavement Areas................................................................... 6
6. Testing and Inspection................................................................................................ 6
GENERAL.................................................................................................................................. 6
APPENDIX A - Site Plan and Boring Logs
Field Exploration
APPENDIX B - Laboratory Testing
Laboratory Test Results
APPENDIX C - 1997 UBC Seismic Design Criteria
Slcdden Engineering
February 25, 2000 -1- Project No. 544-0006
00-02-075
INTRODUCTION
This report presents the results of our Geotechnical Investigation performed in order to provide
recommendations for the design and construction of the foundations for the gas station/mini mart
building, carwash, pump island canopy and related site improvements. The property is located on the
northwest corner of Highway I I 1 and Dune Palms Road in the City of La Quinta, California. The
associated site improvements will include, paved driveways and parking lots, underground utilities, and
landscape areas.
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 materials 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 proposed project is located on the northwest corner of Highway 11 I and Dune Palms Road in the
City of La Quinta, California. The preliminary site plan indicates that the project will include a gas
station/mini mart, a car wash, -a fueling island canopy, and underground fuel storage tanks. It is our
assumption that the proposed mini -mart building will be of relatively lightweight wood -frame or steel -
frame construction. The associated site improvements will include paved driveways and parking areas,
landscape areas and various underground utilities.
The project site is presently vacant and the ground surface is presently clear as a result of recent grading.
During our field investigation the site topography was dominated by a large sand dune that provided
surface relief of over 10 feet. However, the site has subsequently been graded including substantial cuts
that resulted in the creation of a fairly level site. Highway 1 I 1 and Dune Palms Road are paved and there
are existing underground utilities along the streets.
Based upon our previous experience with similar lightweight commercial structures, we expect that
isolated column loads will be less than 30 kips and wall loading will be less than 3.0 kips per linear foot.
Future grading is expected to include minor cuts and fills to construct a level building pad and 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.
SUBSURFACE CONDITIONS
The site is underlain primarily by fine-grained windblown sands. In general, the site soils appeared
somewhat loose throughout the depth of our borings but sampler penetration resistance (as measured by
blowcounts) indicates that the site soils are generally firmer with depth. Windblown sands were
prominent near the surface within each of our borings as a result of a loose sand dune that occupied the
site. Silty sands with some scattered thin silt layers were encountered below a depth of 15 feet within two
of our borings: .
Slodden Engineering
1
i
11
February 25, 2000 -2- Project No. 544-0006
00-02-075
The site soils were found to be generally dry throughout the depth of our borings. Moisture contents
varying from 0.5 to 6.4 percent were determined for the samples obtained within our borings.
Laboratory classification testing indicates that the near surface soils consist primarily of fine grained
windblown sands. Expansion testing indicates that the surface soils are non -expansive and fall within the
"very low" expansion category in accordance with the Uniform Building Code classification system. The
generally loose and dry conditions suggest that native soils underlying the site may be susceptible to
potentially damaging settlements due to hydroconsolidation and compression.
Groundwater was not encountered in our borings and groundwater is expected to be in excess of 80 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 commercial
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 generally loose
condition of the near surface native soils, remedial grading including overexcavation and recompaction is
recommended for the proposed building areas. We recommend that remedial grading within the proposed
building areas include overexcavation and recompaction of the 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 and groundwater -is expected to -be in excess of 100
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 8:5
kilom`eter's of the San -Andreas fauli' 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 structures. 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.
Caving did occur within each of our exploratory borings and the surface soils will 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 C. Soil conditions
should be verified in the field by a "Competent person" employed by the Contractor.
The --surfacersofls- encountered -during .our:investigation-were found wbe_nod-expansive.) Laboratory
testing indicated an Expansion Index of 0, -,which corresponds with the "very low" 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.
Slodden Engineering
February 25, 2000 -3- Project No. 544-0006
00-02-075
The following recommendations present more detailed design criteria, that have been developed on the
basis of our field and laboratory investigation.
Foundation Design: The results of our investigation indicate that either conventional -shallow 7
continuous -footings -or._isolated pad footings; that are supported upon properly compacted soils,
may be expected to provide satisfactory support for the proposed structures. 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 forsingle story,
structures. Isolated square-or_rectangular footings at least 2 -feet square may be designed using an
allowable bearing -value. d 2000 ounds-per. square foot. ,Continuous footings at.least 12.inches
wide -maybe_ designed_ sing an -allowable bearing -value of "180 pounds per square foot.
Allowable increases ofsf for each additional 1 -foot Df width and 200 psf for each additional
-inche of depth may be utilized for larger footings. The maximum allowable bearing pressure
should be 3060 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.
Because of the hydroconsolidation potential'of the soils underlying the site, 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 engineered fill soils. 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.
Lateral Design: Resistance to lateral loads can 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 0.45 between soil and concrete may be used with dead
load forces only. A passive earth pressure of 275 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.
Slodden Engineering
February 25, 2000 4- Project No. 544-0006
00-02-075
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. Final design criteria should be established by the Structural Engineer.
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 -barriers should be protected by at least
two-inches�of_sand! in: order -to -reduce the possibility of damage 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
approximately 555:parts:per_million (ppm) Soluble sulfate concentration will likely change as a
result of the recommended site grading. Soluble sulfate content should be determined after
grading and appropriate concrete mix designs should be selected in accordance with UBC Table
19-A-3.
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. R -Value testing performed on similar soils encountered on an
adjacent lot resulted in an R -Value of 62. On this basis, a pavement section of 3.0 inches of
asphalt on 4.0 inches of base material should be applicable for the design of the majority of the
onsite pavement. The appropriate pavement sections for off site improvements will be dependent
upon traffic indices determined by the City of La Quinta, California.
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.
Pavement and slab designs are tentative and should be confirmed at the completion of site
grading when the subgrade soils are in-place. This will include sampling and testing of the actual
subgrade soils and an analysis based upon the specific traffic information
Slodden Engineering
February 25, 2000 -5- Project No. 544-0006
00-02-075
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
could vary from 15 to 20 percent. Subsidence of the surfaces which are scarified and compacted
should be between 0.1 and 0.2 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 the
stripping of the organic material from the site, the removal of deleterious materials and the
removal of debris, 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 and debris will
be very important. All surfaces to receive compacted fill should be cleared of roots,
vegetation, debris, and other unsuitable materials which should be removed from the site.
Soils that are disturbed due to the removal of the surface vegetation, previous
improvements or artificial fill material should be replaced as controlled compacted fill
under the direction of the Soils Engineer.
2. Preparation of Building Areas: Within the building areas, removal and
recompaction of the primary foundation bearing soils is recommended. As a minimum,
removals within the building areas should extend to a depth of at least 2 feet below
existing grade or 2 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% relative compaction is attained. Once deleterious materials are
removed, the. native soils and artificial fill materials may be placed as controlled
compacted fill. Overexcavation should be observed by a representative of Sladden
Engineering and compaction should be verified by testing. Overexcavation should
extend at least 5 feet laterally beyond the footings.
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% 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% 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 evaluation of proposed import materials.
February 25, 2000 -6- Project No. 544-0006
00-02-075
The contractor shall be responsible for delivering material to the site, which complies
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. At the time of our investigation, the subsoils were found to
be quite dry. A more uniform moisture content should be attained during recompaction
and fill placement.
5. Preparation of Slab and Pavement Areas: All surfaces to receive asphalt concrete
pavement 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 minimum 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. The minimum acceptable
degree 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.
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 USA Petroleum Corporation and its consultants 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
operations by a representative of Sladden Engineering. All recommendations are considered to be
tentative pending our review of the grading operations 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.
Our investigation was conducted prior to the completion of plans for the project. 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
■
APPENDIX A
Site Plan
Borings Logs
1�-
Slodden Engineering
i
i
APPENDIX A
Site Plan
Borings Logs
1�-
Slodden Engineering
1
1
1
1
1
1
1
1
1
1
1
1
APPENDIX A
FIELD EXPLORATION
For our field investigation, 3 exploratory borings were excavated on January 26, 2000, using a truck
mounted hollow stem auger rig (Mobile B53) in the approximate locations indicated on the site plan
included in this appendix. Continuous logs of the materials encountered were made on the site by a
representative of Sladden Engineering. 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 (generally in 6 inch increments) 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. Samples
were then transported to our laboratory for further observations and testing.
Slcdden Engineering
i
I .
I 1
, 1 \
\-
1 �
I R W
1 ,
a
' 22 �, v
1
� 1
I
I1
••�._.`___�_�_ ___ OU_NE _PALMS -ROAD _
4
2 Approximate Boring Locations
I�Iz
N.T.S.
NORTH
` Proposed Mini Mart & Gas Station
Highway 111 and Dune Palms Road / La Quinta, California
Date: 1-26-00 Boring No. 1 Job No.: 544-0006
I
�
�
o44
�
'
^
DESCRIPTION
>i
Q
o
N y
0 a
REMARKS
5
A:
>_1O
U1
U
GU
p
U)
is V
�D
F
4
O
o U
o
Sand: Grey brown,
SP
fine grained
5
5/6/7
I 0.5
10
5/8/8
---
1.5
15
5/6/10
"
"
I ---
2.6
---
20
4/6/10
"
---
5.3
---
Scattered silt layers up to 1" thick
25
-
6/6/10
( "
I
I
I
2.6
I Abundant interbedded silt layers
Silty Sand: Light brown,
SM
30i
fine grained
5/6/15
1.5
_
IU Standard Penetration
I
Total Depth = 31.5'
I I No Bedrock
35
Sample
i I
I No Groundwater
40
45
50
-
_
•
I �
Note: The stratification lines
55
I
represent the approximate
boundaries between the soil types;
I
I
the transitions may be gradual.
L
Proposed Mini Mart & Gas Station
Highway 111 and Dune Palms Road / La Quinta, California
Date: 1-26-00 Boring
No. 2 Job No.: 544-0006
o
I
a�
>
.
o
I
DESCRIPTION
q I
REMARKS
a
a�3
2
E-
_�
(�
U]
U
_o
U
U
°S
_
and: Grey brown,
SP
fine grained
5
-
-
6/6/1 2
---
1.0
---
10
-
4/8/8
..
1.5
---
155/7/10
I
'
I 2.0
i -
20
-
Silty Sand: Light brown,
SM
4/7/10
fine grained
6.4
Thin interbedded silt layers
_
T Standard Penetration
Total Depth = 21.5'
I No Bedrock
Sample
No Groundwater
25
i
I
30
35
40
45
_
I
50
_
Note: The stratification lines
55
represent the approximate
boundaries between the soil types;
I
I
the transitions may be gradual.
Proposed Mini Mart & Gas Station
Highway 111 and Dune Palms Road / La Quinta, California
Date: 1-26-00 Boring
No. 3 Job No.: 544-0006
I
o
"DESCRIPTION
q
REMARKS
a�
3
F
o
a
r1
U I
Pel
ri1
�D —9
o
�U
o
Sand: Grey brown,
SP
-
fine grained
4/8/8
I�
I
!
--- I
1.0 I
---
106/7/9
-
'
I
2.6
---
15
-
8/8/10
I
2.6
_
T Standard Penetration
Total Depth = 16.5'
No Bedrock
Sample
No Groundwater
20
25
30
_
35
!
I
�"
i
40
45
50
Note: The stratification lines
55
i represent the approximate
I
I
i
I he transitions may be gradual. .
■
i
■
1
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 conso.lidation, 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: These 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.
Slcdden Engineering
IRi
A
w 109
A
108
8.5 9 9.5 10
Moisture Content (%)
METHOD OF COMPACTION
ASTM D-1557-91, METHOD A OR C
BORING MAXIMUM UNIT WEIGHT
1@0-5' 111
Job No.: 544-0006
10.5 11
OPTIMUM MOISTURE CONTENT
9.5
MAXIMUM DENSITY -OPTIMUM MOISTURE CURVE
1 � Y
1.0
.8
.6
.4
.2
z 0
DIRECT SHEAR TEST
0 .2 .4 .6 .8 1.0 1.2 1.4 1.6 1.8
0 = 32°
c = 50psf
where 0 = Shear Angle
c = Cohesion
�
i
r
000.<l
,
0 .2 .4 .6 .8 1.0 1.2 1.4 1.6 1.8
0 = 32°
c = 50psf
where 0 = Shear Angle
c = Cohesion
APPENDIX C
1997 UBC Seismic Design Criteria
Slodden Engineering
February 25, 2000 Project No. 544-0006
00-02-075
1997 UNIFORM BUILDING CODE SEISMIC DESIGN INFORMATION
The International Conference .of Building Officials 1997 Uniform Building Code contains
substantial revisions and additions to the earthquake engineering section in Chapter 16. New
concepts contained in the updated code that will likely be relevant to construction of the proposed
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.
Fault Zone
Approximate Distance
From Site
Fault Type
1997 UBC
San Andreas
8.5 km
A
San Jacinto
32 km
A
Based on our field observations and understanding of local geologic conditions, the soil profile
type judged applicable to this site is Sp, 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.
Slodden Engineering
Near -Source
Near -Source
Seismic
Seismic
Seismic
Acceleration
Velocity
Coefficient
Coefficient
Source
Factor, Na
Factor, Nv
Ca
Cv
San Andreas
1.1
1.3
0.44 Na
0.64 N„
San Jacinto
1.0
1.0
0.44 Na
0.64 N„
Slodden Engineering