Mountain View Country Club Villas TR 30357 - Geotechnical Investigation Update*'Sladden Engineering
6782 Stanton Ave., Suite A, Buena Park, CA 90621 (714) 523-0952 Fax (714) 523-1369
397725 Garand Ln., Suite G, Palm Desert, CA 92211 (760) 772-3893 Fax (760) 772-3895
0
March 21„ 2005 Project No. 544-1274
05-03-304
Toll Brothers, Inc.
73-121 Fred Waring Drive, Suite 100
Palm l0esertt California 92260
Project: Proposed Condominium/Villas Project '-
Tract 31349, Lot 185
La Quinta, Califomia
Subject: Foundation Plan Review
Ref: Ccotcchnical Investigation Update prepared by Sladden Engineering dated September 23,
2002, Project No. 544-1,274, Report No. 02709-551.
As requested, we have reviewed the Foundation Plans and Details prepared for the condominium project
by Gouvis Engineering Consulting Group. Based upon our review,.it appears that the recommendations
included within the referenced geotechnical report have been properly incorporated into these plans.
If you have questions regarding this memo, please contact the undersigned.
Respectfully submitted,
SLADDEN ENGINEER G
0
ANOF�
d A Brett L Bre. Anderson n O
- � Exp.9/30/06 rn �^
Principal Engineer �V
. Letter/ c �
p OF CA110
Copies: 1/Toll. Brothers, Inc.
' 2/RNM Design
6
G _ d £ l t 1 mq '°�d/J G ,1 l '1S/1 G L l 500E £G d�W (03M) IM10 Wl'; d N100uflS W08A
Sladden Engineering
6782 Stanton Ave., Suite A, Buena Park, CA 90621 (714) S23-0952 Fax (714) 523-1369
39-725 Garand Ln., Suite G„Palm Desert, CA 92211 (760) 772-3893 Fax (760) 772-3895
October 4, 2002 Project No. 544-1274
02-1'0-614
'Coll Brothers; hle.
74-923 Howley Lane [:ast, Suite 2-220 "
Palm Desert, California 92260
Attention: Mr. Lee Dotson
•Project: Mountain View CountryClub
Jefferson Street
La Quinta, California
Rcf: Geotechnical Engineering Report prepared by Buena Engineers, Me. dated September.6,
1989, Project No. 87-11645-P1, Report No. 89-09=703.
Geotechnical Update prepared by Sladden Engineering dated.October 29, 2001,'Project
No. 544-1274, Report. No. 02-09-551.
Subject: Supplemental Soils Investigation
Presented herewith `is "the*.report of our Supplemental Soils Investigation prepared for the proposed•,
clubhouse and maintenance building. The clubhouse site is to be located within the central portion and
the maintenance. building will be located within .the southeastern portion of the Mountain View Country
Club development in,the City of La Q.uinta, California. This report was prepared in order to provide
specific information regarding the site soils conditions along with recommendations for foundation design
for the Mountain View clubhouse and maintenance building.
This report presents the results of, our supplemental field investigation and laboratory testing along with
conclusions and recomtriendations for foundation design and remedial grading. This report completes our
supplemental 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 or the above referenced reports, please contact the undersigned
Respectfully submitted,
SL,kDDEN ENGINEERING
0FF.Sseit
Brett L. nde s �r "
Principal Engineer z
No. C 45389
S I;R/pc EXP. 93� 0-200
s�qt clvly-
FOF CA1If�Q`
-Copies: 2/Toll Brothers, Inc.
2/Thrcc Architecture.
£ d 98901ZZ089 '0N/D:6 '1S/ lb 6 900Z Z UJ (NOW) 183S34 Wlbd NHOb1S W08J
RE -PORT OF
SUPPLEMENTAL SOILS INVESTIGATION
CLUBHOUSE & MAINTENANCE BUILDING
MOUNTAIN VIEW COUNAY CLUB- ,
LA QUINTA, CALIFORNIA.
October 4, 2002
TABLE 0, F CON71.7ENTS
INTRODUCTION.... ..................................................... ........ .....................
SCOPEOF' WORK .................... ....... ; ............... ........................................
PROJECT DESCRIPTION ........................................ .......... ..................................................
SUBSURFACE CONDITIONS ................................... 1.1.11.11 ....................... ...... ...............
CONCLIJSIONS AND RECOMMENDATIONS ............................. ................................ 2
-Foundation Design ..................... .......................................................................... 3
Settlements ......................... 11 .............
............... ............................................................ 2 .........
LateralDesign .................................... ...... 11.1'..." ................ 1 ............. I ..............................
RetainingWalls ............................ ........... ....... .. ........ 11, ......................... * ........................ 3
Fxp,ansiv'e Soils .............................................. ................. ................................................
GENERAL ..................
......................... ............................. ........................................ 5
APPENDIX A - Site -Plan and 8oring Logs
Ficld Exploration
APPENDIX B 1997 U13C Seismic Design Critepa
d 9890LZ0.89,'ON/0br: 6 'iS/ t:,6 HE Z 8 3 J (NOW) 183S30 W]Vd N300VIS W689
October 4, 2002
INTRODUCTION
Project No. 544-1274
02-10-614
This report presents the results of our Supplemental Soils Investigation prepared in order to provide
specific recommendations for the design and construction of the maintenance building and clubhouse for
the Mountain View golf club development. The clubhouse site is to be located within the central portion
and the maintenance building will be located within the southeastern portion of the Mountain View
Country Club project site in the City of La Quinta. The supplemental ,investigation was performed to
assess the soils conditions within the clubhouse and maintenance building areas in order to provide
specific recommendations for use in foundation design.
SCOPE OF WORK
The purpose of our supplemental investigation was to, determine certain engineering characteristic%ofthe
near surface soils within the clubhouse and maintenance building areas in order to develop specific
recommendations for foundation design and foundation area preparation. Our investigation included .field
exploration, laboratory testing, engineering analysis and the preparation of this report. The information
provided within this report is intended to supplement the information. and recommendations included
within the previous beotcchnical reports prepared by Sladden Engineering and Rucna'Engineers, Inc.
PROJECT DESCRIPTION
The clubhouse site is located within the central portion of the Mountain View development and the
maintenance building will be located within the southern portion of the site along Avenue 52 in the City
of 1-a Quinta; California. The clubhouse and maintenance building areas have been rough graded
including overexcavation and recompaction of the surface soils.
The clubhouse area rough grading -has been completed. Rough grading included the overexcavation and
recompaction of the native surface soils, the placement of over 10 feet of engineered fill material and the
excavation of the lower/basement level. The rough grinding of the maintenance building area has also
been completed including overexcavation and recompaction of the surface soils.
SUBSURFACE CONDITIONS
Based upon the soils conditions encountered within our'recent exploratory borings and ourobservations
and testing* during rough grading, it is clear that the clubhouse.and maintenance building sites are
underlain primarily by engineered fill material placed during the rough grading of the building sites.
The engineered fill soils and native soils appeared firm throughout the depth of our exploratory borings.
An expansion index of 0 was determined for the near surface soils that correspond with the "very low"
expansion category in accordance with Table I $-l-B of the 1997 Uniform Building'Code (UBC).
CONCLUSIONS AND RECOMMENDATIONS
Based upon our: supplemental field investigation and laboratory testing performed along with our previous
testing and observations during grading; it is our opinion that the ,proposed clubhouse and maintenance
building construction is feasible from a. soil mechanic's standpoint provided that the recommendations .
included in this report and the previous report.~ are considered in foundation design.
.1-1,1.. Jr...........
5 d 9890LLZ089 'ON/W 6 '1S/ lb: 6 900Z, Z EON) 181S30 Wldd N1a4d1S W081
October 4, 20.02 -2- Project No. 544-1274
02-10-614
Based upon the uniform and compact conditions of the 'previously placed engineered fill soils as
confirmed within our exploratory borings, additional remedial grading should not be necessary for the
clubhouse or maintenance, building areas.
Groundwater was not encountered within our borings that extended to a depth of approximately 30 feet
below the existing ground surface. Grondwater is expected to be in excess of 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 ?'?
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,desigied by professionals familiar with the
geologic and seismic setting of the site. As a minimum, structure design'should conform to Uniform
Building Code (iJBQ requirements for Seismic 'Lone 4. Pertinent seismic design criteria as outlined in
the 1997 UK, is summarized in Appendix B of this report_
Caving did occur to varying degrees within each of our exploratory borings and the surface soils maybe
susceptible to caving within deeper. excavations. All excavations should be constructed in accordance
with the normal CaIOSHA excavation criteria. On the basis of our observations of the materials
encountered, we anticipate that the subsoils will conform io those described by CalOSHA as Type'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 non -expansive.
Laboratory testing itid+icated an Expansion Index of 0 for the near surface alluvial sands that corresponds
with the "very low" expansion category in accordance with UBC Table 18-1-B. 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 for use in retaining wall design, that
have been developed on the basic of our supplemental field and laboratory investigation.
Foundation Design!. ' The results of our investigation indicate that conventional shallow
continuous footings that.are supported upon properly compacted soils may be expected to provide
satisfietory support for the proposed retaining walls. Remedial compaction of the foundation -
bearing s<)ils should be performed as necessary based upon field conditions.
Conventional shallow spread footings should be bottomed into properly compacted fill material at
least 1.2 inches below lowest adjacent grade for single story structures and 18 inches below lowest
adjacent grade for two story structures. Continuous footings should be at least 12 inches wide
and isolated paid footings should be at least two feet wide. Continuous footings and isolated pad
footings may be designed using allowable bearing pressures of 1800 psf and 2000' psf,
respectively. increases in allowable bearing pressure ntay be realized with increased footing sire.
Allowable bearing pressure may be increased by 200 psf for each additional I foot of width and
250 psf for each additional I foot of depth. The maximum allowable bearing pressure should be
3000 psf. The recommended allowable bearing pressures may be increased by 1/3 when
considering wind and seismic loading.
9 d 9890ZZZ089 '.0N/W'6 U/Zt:6 90OZ L 9100W) 1d1S1a WlVd N1aab1S W0a1
October 4, 2002 73- Project No. 544-1274
02-10-614-
The recommendations made in the preceding paragraph 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 one 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 0.43 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 that are poured against properly compacted native soils.
Passive earth pressure should be ignored within the upper I foot- When used in combination,
either the passive resistance or the coefficient offriction should be reduced by one-third.
Retaining Walls: The proposed reinforced masonry retaining walls may be designed using
"active" pressures. Active pressures may be estimated using an equivalent fluid weight of 35 pef
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.
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 Toll Brothers, Inc. 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 repoil 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.
Z d 9890LLZ089 '0N/D:6 '1S/Zb:6 900Z Z 933 (NOW) '1a3S30 Wldd N30ad1S WO83
APPENDIX A
FIELD EXPLORATION
For our supplemental field investigation 4 .exploratory Borings were excavated on September 20, 2002,
using a Mobile B61 drilling rig and hollow -stem augers. The exploratory borings were excavated in the
approximate locations indicated on the site plan included in this appendix. Continuous logs of the soil
observed within Our- exploratory borings were :prepared on' the site by a representative of Sladden
Engineering. Boring lobs an: included in, this iappcndix.
Representative undisturbed samples were obtained within our borings 'by driving athin-walled steel
penetration. sampler (California split spoon sampler) or a Standard Penetration Test (SPT) sampler with. a
140 pound hammer dropping approximately 30 inches (A,STM D1.586). The number of blows required to
drive the sampler; 18 inelicS W61S rcCC�rdt;d ill 6-inch inurcrricnls and bluwwunts 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
. inclies. Undisturbed samples were rtmovtd from the sampler and �placcd 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.
6 d 98.90LZ'089 'ON/P: 6 -1VO: 6 500Z- Z 231 (NOW). 18]S3a Wldd N340d1S W083
AW S-2002 10:42m From-TNREE ARCNITECTURE TS
ri M
. ` L
J\ �
+Zi1S510il0
imp
T-3T6 P.009/006 F-602
a
• 4•
Ol d 9890ZZZ089 '0N/P:6 1S/£b:6 900Z Z 011(NOW) 1a3S30 WIN NHGV]S WO8J
5--
Mountain View Country Club
Maintenance Facility and Spa / La Quinta, Califordiia
Date; 9.20-02
Boring No. 1 - Maintenaee Facility Area Job No.; 544-1274
A v�'
U W Descri lion U) 5 -�Z Rctnarks
0
Artificial Fill
-
Silty Sand: TA Gray, Dry
SM
5
10/18/34
Silty Sand: Lt Gnry, Mont
SM
104
6
10
; «
e':ekix
14/30/29
Slightly Silty Sand: I..t Gray, Damp
SP
100
5.
`
15
M
16/34/42
Slightly Silty Sand: Lt Gray Dry
SP
109
3
>NEE`
hX.
Native Surly
20 11/14/21 F Sandy Silt: Gry Brn, W6t ML 91 16
25 9/10/1.1 Silt: Gry Brn, Wet INC 85 • 35.
Recovered Sample Total Depth = 26.5'
- I No ):Bedrock
30 Unrceovcred RWY11)I& o'GroUn(lwater
SUuidard Penetration Samplc
_ t
35
40
45
Nutc; 'I lie stratification line; represent the approximat.c _
lxxundaries between the soil (. ics, tlic transition may bC
50 gradual,
Z l d 989OZZZ089 'ON/D : 6 '1S/bb: 6 900Z Z 833 (NOW)
183S34 W1dd N300V1S W08J
Mountain View Country Club
Maintenince Facility And Spa / La Quints, California
Date: 9-20402
Boring No. 2 - Club House & Spa Area
Job No.: 544-1274
t-
0
u°
Description
v,
o
Remarks ..
- 0
rtificiai Fill
.
Silty Staid: Gray Ban, Damp
SM
,
5
15/27/40
Silty Sand: Gray -lam, Moisl
SM
109
11
10
14/23/17
Silty Sand: Gray,tirn, Damp
SM
107
7
15
29/30/50
Silty Sand: Gray 13m, Moist'
SM
107
10
20
�V tk
r�s
]9134/4O
Slighlty Silty Sand: (fray, Dianli -
SP
..109
7
•
fltlVL' Soils25
23/45/30
Sandy Silt: Cry
Brn, Damp
5
R
£ l d 9890tLZ089 'ON/D:6 '1SM : 6 500Z L I8h. (NOW) IM30 Wldd N300d1S W083
Mountain View'Country Club •
Maintenance Facility and Spa / La Quinta, California
Dote: 9-20-02 Boring No. 3 Job No.: 544-1274
�„•
Description
�
�+
Remarks
0
ificail Pill
-
Silty Sand: Gray l3rn, Damp
SM
w
,
5
15/23/29
Silly Sand: Gray tim, Damp
SM
l 10
7
t t
10
11/20/44
Silty Sand: Cray Hrn, Wet
SM
116
16
l5
20/29/47
Silty Stutd: Cray Rrn, Moist
SM
109
10
,stive Soils
20
] S/19/2fi
Slightly silty Sand: (ity Brn, Dump
9P,
103
6
soa
t
y
25
9/20/2l1
Silty F Simd: City Rrn, Damp
SM
93
6'
-
RccovLred Sample
Touil Depth = 26.5'
o Bedrock
30
'co
LJnreeovcrcd Sample
o Groundwater -
Standard Penetration Saillple
�
35
�r
40
,
45
-
Note: The stratification lines represent the approxunate
boundaries between the soil .types; the transition may be
50
gradual.
b f d 9890LZZ08.9 'ON/0 6 1S/9b 6 900'Z 1. 831 (NOW)
AIM W N .N'IOXIS W08J
' Mountain View Country Club '
Z Maintenance Facility and Spa / La Quints, California
Date: 9-20-02
Boring No. 4 - Basement Area Job No.: 544-1.274
Dcscri tion
0
'"
o
Remarks
0,
Artificial Fill
Silly Land: Gray Tint, Damp
tiM
5
1.2/19/22
Silty Swid: Gray BnI, Damp
SM
108
6
-Native
Soils
10
12/22/26
Silty Sand. Gray Brn, Damp
5M
97
6
15
11/15/20
Silty F Sfmd; Lt Rm, Dry
SM
99
1
-
Recovered Sample
Total Depth = 16.5'
-
I . i
No Btdrock-
20
Unrccovered Sample
No Grouttdwnter
-
Standard Penetration Stlinple
30
35`
,
r
40
,
45
Note: The stratification lines represent the approxilttnte
-
boundaries between the soil types; the transition miry tv
50
6rndual.-
5l d 9890LLZ089'�N/Ob:6 1S/5b 6 500Z t 83J(NOW) 183S30 Wldd N30Ob1S W08J
October 4, 2002 -7- 'Project No. 544-1274
- 02-10-614
A
` y 1997 1JNIIWAWV><'"91H WNC 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 be relevant to construction of the proposcd0'residential structures are
summarized below., ;
Ground shaking is expected to.he the primary hazard'most, likely to affect the site, based upon prokimity
to significant faults -capable of generating large earthquakes. Major fault zones considered to be''most-
likely to create strong''gtound shaking at,the site are listed below.
r
' f Approximate Destance Fault Type
Fault Zone
From Site
,
1997 UBC '
SawAndreas
9.2 kin
A
San Jacinto .�.,
34.1 km
A
r '
Based on our field observations and understanding of local geologic conditions, the .soil profile type
judged applicable to this site is So, 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. '
Near-SoYrCc
Ncar-Source .
Seismic
Seismic
Seismic
Acceleration
'Velocity
Coefficient
Coefficient
Sourcc
Factof; N.
Factor' N.
CA
C,
San •Andreas
l .0'
1.25 _
0.44,N,
0.64 N,,,
San'Jacinto,
1.0
1.0
0.44•NA
0.64 N
Sudden Engineering
6782 Stanton Ave., Suite A, Buena Park, CA 90621 (714) 523-0952 Fax (714) 523-1369
39-725 Garand Ln., Suite G, Palm Desert, CA 92211 (760) 772-3893 Fax (760) 772-3895
ISEP
MOMSTMI.
September 21, 2004 2 9 2004 Project No. 544-1274
41-09-670
Toll Brothers, Inc.
73-121 Fred Waring Drive, Suite 100
Palm Desert, Ca 92260
Attention: Mr. Lee Dotson
Project: Mountainview Country Cl
Condominiums — Lot 185
La Quinta, California
Subj ect: Geotechnical Update
BY: --------------------
CITY OF LA UIo A
BUILDING & sAFETY
DAT�10BY
Reference: Geotechnical Engineering Report prepared by Buena Engineers, Inc. dated September 6,
1989, Job No. B7-1645-P1, Report No. 89-09-703'.
As requested, we have reviewed the referenced Geotechnical Engineering Report as it relates to the
design and construction of the proposed condominium complex. In addition, we have.visited the project
site to observe the present conditions. The condominium complex will be constructed on Lot 185 along
Via Tesoro within the central portion of the Mountain View Country Club Development in the City of La
Quinta, California.
The referenced Geotechnical Engineering Report includes recommendations for remedial site grading
and the design and construction of the proposed residential structure foundations. Based upon our review
of the referenced report and our recent site observations, it is our opinion that the recommendations
included in the referenced Geotechnical Engineering Report remain applicable.
The structural values included in the referenced report should be applicable for use in the design of the
proposed residential structure foundations. Conventional shallow spread footings should be at least 12
inches deep and bottomed into firm compacted soils. Continuous footings at least 1 foot wide and
isolated pad footings at least 2 feet square may be designed using allowable bearing pressures of 1200
and 1400 pounds per square foot (psf), respectively. Allowable increases of 200, psf for each additional 1
foot of width and 300 psf for each additional 6 inches of embedment depth may be utilized. The
maximum allowable bearing pressure should be 2000 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.
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.
These elastic settlements are expected to occur during construction.
September'21, 2004 -2- Project No. 544-1274
04-09-670
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
0.49 between soil and concrete may be used for dead load forces only. A passive earth pressure of 300
pounds per square foot,.per foot of depth, may be used along the sides of footings, that are placed against
properly compacted soils. Passive earth pressure should be ignored within the upper 1 foot except where
confined (such as beneath a floor slab).
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. Walls should be provided with adequate drainage.
It is our opinion that the remedial grading initially performed including overexcavation and recompaction
of the bearing soils within the proposed building areas remains applicable. Because the pads have been
rough graded, the remedial grading necessary at this time should be minimal
The building pad areas should be cleared of any surface vegetation and root systems prior to grading.
The exposed surface should be scarified, moisture conditioned and compacted to a minimum of 90
percent relative compaction. Fill material may then be placed in thin lifts at near optimum moisture
content and compacted to at least 90 percent relative compaction. Compaction should be verified by
testing.
It should be noted that the site is located within a seismically active area of Southern California and it is
likely that the proposed structures will experience strong ground shaking as a result of an earthquake
event along one of the faults in the region during the expected life of the development. As a minimum,
structures should be designed based upon Seismic Zone 4 design criteria included in the Uniform
Building Code (UBC). The potential for liquefaction or other geologic/seismic hazards occurring at the
site is considered to be negligible.
We appreciate the opportunity to provide service to you on this project, if you have any questions
regarding this letter or the referenced report please contact the undersigned.
Respectfully submitted,
SLADDEN ENGINEE
Brett L. Anderso`i 4tszs
Principal Engineer (((i
O- 9j3pmb) *
Letter/lh
Copies: 2/Toll BrsT P
4/MDS Consulting
Sladden Engineering
s
September 21, 2004 -3- Project No. 544-1274
04-09-670
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 in Chapter 16. Concepts contained in the
updated code that will likely be relevant to construction of the proposed structures are summarized
below.
E
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
9.0 km
A
San Jacinto
33 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.
Near -Source '
Near -Source
Seismic .
Seismic
Seismic
Acceleration
Velocity
Coefficient
Coefficient
Source
Factor, N,,
Factor, N,,
Ca
C,,
San Andreas
1.05
1.3
0.44 Na
0.64 N,,
San Jacinto
1.0
1.0
1 0.44 N,,
0.64 N„
Sladden Engineering
Staddeh Engineerin
J
6782 Stanton Ave., Suite A, Buena Park, CA 90621 (714) 523-0952 Fax (714) 523-1369
39-725 Garand Ln., Suite G, Palm Desert, CA 92211 (760) 772-3893 Fax (760) 772-3895
October 4, 2002 Project No. 544-1274
02-10-614
Toll Brothers, Inc.
74-923 Hovley Lane East, Suite 2-220
Palm Desert, California 92260
Attention: Mr. Lee Dotson
Project: Mountain View Country Club
Jefferson Street
La Quinta, California
Ref: Geotechnical Engineering Report prepared by Buena Engineers, Inc. dated September 6,
1989, Project No. 137-11645-P 1, Report No. 89-09-703.
Geotechnical Update prepared by Sladden Engineering dated October 29, 2001, Project
No. 544-1274, Report No. 02-09-551.
Subject: Supplemental Soils Investigation
Presented herewith is the report of our Supplemental Soils Investigation prepared for the proposed
clubhouse and maintenance building. The clubhouse site is to be located within the central portion and
the maintenance building will be located within the southeastern portion of the Mountain View Country
Club development in the City of La Quinta, California. This report was prepared in order to provide
specific information regarding the site soils conditions along with recommendations for foundation design
for the Mountain View clubhouse'and maintenance building.
This report presents the results of our supplemental field investigation and laboratory testing along with
conclusions and recommendations for foundation design and remedial grading. This report completes our
supplemental 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 or the above referenced reports, please contact the undersigned
Respectfully submitted,
SLADDEN ENGINEERING
BretqLnie so
Principal Engineer
SER/pc
Copies
2/Toll Brothers, Inc.
2/Three Architecture
REPORT OF
SUPPLEMENTAL SOILS INVESTIGATION
CLUBHOUSE & MAINTENANCE BUILDING
MOUNTAIN VIEW COUNTRY CLUB
LA QUINTA, CALIFORNIA
October 4, 2002
TABLE OF CONTENTS
INTRODUCTION....................................................................................................................... 1
SCOPEOF WORK..................................................................................................................... 1
PROJECTDESCRIPTION......................................................................................................... 1
SUBSURFACE CONDITIONS..........................................................:....................................... 1
CONCLUSIONS AND RECOMMENDATIONS..............:....................................................... 2
FoundationDesign................................................................................................................ 3
Settlements............................................................................................................................ 3
LateralDesign....................................................................................................................... 3
RetainingWalls..................................................................................................................... 3
ExpansiveSoils.......................................:.............................................................................. 3
GENERAL......................................................... ..... 5
APPENDIX A - Site Plan and Boring Logs
Field Exploration
APPENDIX B 1997 UBC Seismic Design Criteria
October 4, 2002 -1- Project No. 544-1274
02-10-614
INTRODUCTION
This report presents the results of our Supplemental Soils Investigation prepared in order to provide
specific recommendations for the design and construction of the maintenance building and clubhouse for
the Mountain View golf club development. The clubhouse site is to be located within the central portion
and the maintenance building will be located within the southeastern portion of the Mountain View
Country Club project site in the City of La Quinta. The supplemental investigation was performed to
assess the soils conditions within the clubhouse and maintenance building areas in order to provide
specific recommendations for use in foundation design.
SCOPE. OF WORK
The purpose of our supplemental investigation was to determine certain engineering characteristics of the
near surface soils within the clubhouse and maintenance building areas in order to develop specific
recommendations for foundation design and foundation area preparation. Our investigation included field
exploration, laboratory testing, engineering analysis and the preparation of this report. The information
provided within this report is intended to supplement the information and recommendations included
within the previous geotechnical reports prepared by Sladden Engineering and Buena Engineers, Inc.
PROJECT DESCRIPTION
The clubhouse site is located within -the central portion of the Mountain View development and the
maintenance building will be located within the southern portion of the site along Avenue 52 in the City
of La Quinta, California. The clubhouse and maintenance building areas have been rough graded
including overexcavation and recompaction of the surface soils.
The clubhouse area rough grading has been completed. Rough grading included the overexcavation and
recompaction of the native surface soils, the placement of over 10 feet of engineered fill material and the
excavation of the lower/basement level. The rough grading of the maintenance building area has also
been completed including overexcavation and recompaction of the surface soils.
SUBSURFACE CONDITIONS
Based upon the soils conditions encountered within our recent exploratory borings and our observations
and testing during rough grading, it is clear that the clubhouse and maintenance building sites are
underlain primarily by engineered fill material placed during the rough grading of the building sites.
The engineered fill soils and native soils appeared firm throughout the depth of our exploratory borings.
An expansion index of 0 was determined for the near surface soils that correspond with the "very low"
expansion category in accordance with Table •18-1-B of the 1997 Uniform Building Code (UBC).
CONCLUSIONS AND RECOMMENDATIONS
Based upon our supplemental field investigation and laboratory testing performed along with our previous
testing and observations during grading, it is our opinion that the proposed clubhouse and maintenance
building construction is feasible from a soil mechanic's standpoint provided that the recommendations
included in this report and the previous reports are considered in foundation design.
Sladden Eitr-ineerin.-
October 4, 2002 -2- Project No. 544-1274
02-10-614
Based upon the uniform and compact conditions of the previously placed engineered fill soils as
confirmed within our exploratory borings, additional remedial grading should not be necessary for the
clubhouse or maintenance building areas.
Groundwater was not encountered within our borings that extended to a depth of approximately 30 feet
below the existing ground surface. Groundwater is expected to be in excess of 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 ??
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 B of this report.
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 CaIOSHA 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 majority of the surface soils encountered during our investigation were found to be non -expansive.
Laboratory testing indicated an Expansion Index of 0 for the near surface alluvial sands that corresponds
with the "very low" expansion category in accordance with UBC Table 18-1-B. 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 for use in retaining wall design, that
have been developed on the basis of our supplemental field and laboratory investigation.
Foundation Design: The results of our investigation indicate that conventional shallow
continuous footings that are supported upon properly compacted soils may be expected to provide
satisfactory support for the proposed retaining walls. Remedial compaction of the foundation
bearing soils should be performed as necessary based upon field conditions.
Conventional shallow spread footings should be bottomed into properly compacted fill material at
least 12 inches below lowest adjacent grade for single story structures and 18 inches below lowest
adjacent grade for two story structures. Continuous footings should be at least 12 inches wide
and isolated pad footings should be least two feet wide. Continuous footings and isolated pad
footings may be designed using allowable bearing pressures of 1800 psf and 2000 psf,
respectively. Increases in allowable bearing pressure may be realized with increased footing size.
Allowable bearing pressure may be increased by 200 psf for each additional I foot of width and
250 psf for each additional 1 foot of depth. The maximum allowable bearing pressure should be
3000 psf. The recommended allowable bearing pressures may be increased by 1/3 when
considering wind and seismic loading.
Sl"dth n Fnninvvrino
October 4, 2002
-3- Project No. 544-1274
02-10-614
The recommendations made in the preceding paragraph 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 one 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 0.43 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 that are poured against properly compacted native soils.
Passive earth pressure should be ignored within the upper 1 foot. When used in combination,
either the passive resistance or the coefficient of friction should be reduced by one-third.
Retaining Walls: The proposed reinforced masonry 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.
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 Toll. Brothers, Inc. 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.
.CI�I//�/ors Fnrrinnnrin�■
APPENDIX A
Site Plan
Boring Logs
APPENDIX A
FIELD EXPLORATION
For our supplemental field investigation 4 exploratory borings were excavated on September 20, 2002,
using a Mobile B61 drilling rig and hollow -stem augers. The exploratory borings were excavated in the
approximate locations indicated on the site plan included in this appendix. Continuous logs of the soils
observed within our exploratory borings were prepared 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 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.,
:mil,.1;
m
4ug715-2002 10:52am From -THREE ARCHITECTURE TS +2145590090. T-3T8 P.006/006 F-802
I'
1
i
I
�- lip a°o
----
� I
Mountain View Count Club
. Country
Maintenance Facility and; Spa / La Q.uinta, California
Date: 9-20-02
Boring No. 1 -'Maintenace'Facilit Area Job No.: 544-1274
o
o
o
o
r
3
•�
Y
•o
a:
A
ci
U
cq
Description
�
o
Remarks
0
:.
ificial Fill
-
•.`•=.
Silty Sand: Lt Gray, Dry
SM
5
10/18/34
Silty Sand: Lt Gray, Moist
SM
I04
6
10
14/30/28
Slightly Silty Sand: Lt Gray, Damp
SP
100
5
15
16/34/42
Slightly Silty Sand: Lt Gray, Dry
SP
109
3
-
ative Soils
20
11/14/21
F Sandy Silt: Gry Bm, Wet
ML
91
16
25
9/10/13
Silt: Gry Brn, Wet
ML
85
35
-
Recovered Sample
Total Depth = 26.5'
-
I
No Bedrock
30
Unrecovered Sample
No Groundwater
-
Standard Penetration Sample
35
40
,
45
-
Note: The stratification lines represent the approximate
-
boundaries between the soil types; the transition may be
50
gradual.
Mounudn"Wow CountrT Club
Maintenance Facility- -�a, California ,Apq.,$.p.a / L4 Quin
Date: 9-20-02 Boring No. 2 - Club House & SI)a Area Job No.: 544-1274
°'
U—
o
Description
�
0
C/)
3
N
U
c�
0
Silty Sand: Gray Bm, Damp
SM
5
15/27/40
Silty Sand: Gray Bm, Moist
SM
109
11
10
14/23/37
Silty Sand: Gray Bm, Damp
SM
107
7
15
29/30/50
Silty Sand: Gray Brn. Moist
SM
107
10
1
Note:,rhe stratification line,; represent the approximate
- bOLIndaries between the soil types: the transition inay be
.50 gradWil.
Fill
ive Solis
al Depth = 26.5'
Bedrock
Groundwater
Mountain View Country Club
Maintenance Facility and Spa / La.Quinta, California
Date-. 9-20-02
Boring No. 3 Job No.: 544-1274
,
o
a_
-
3
o
U
o
o
o
A
vs.
U
pq
Description-
ry)
�D
o
Remarks
0
ificail Fill
Silty Sand: Gray Brn, Damp
SM
5
`:
15/23/29
Silty Sand: Gray Brn, Damp
SM
110
7
10
11/20/44
Silty Sand: Gray Brn, Wet
SM
116
16
15
<•:`:;
20/29/47
Silty Sand: Gray Brn, Moist
SM
109
10 -
-
ative Soils
20
XX
15/19/26
Slightly Silty Sand: Gry Bm, Damp
SP
103
6
25
9/20/20
Silty F Sand: Gry Brn, Damp
SM
93
6
-
Recovered Sample
Total Depth = 26.5'
-
I
o Bedrock
30
Unrecoveied
No Groundwater
-
Standard Penetration Sample
35
40
45
Note: The stratification lines represent the approximate
-
boundaries between the soil types, the transition may be
50
gradual
ghrlde n Fnvineexiiw
Mountain View Country:Club
Maintenance Facility and :Spa / La Quinta, California
Date: 9-20-02
-Boring No. 4 - Base'ment"Area Job No.: 54.4-1274
4.
n
a
�c
+�
U
a
q
ri
-
U
-
Description
U)
a
o
Remarks
0
':
ificial Fill
-
Silty Sand: Gray Brn, Damp
SM
5
<<>
12/19/22
Silty Sand: Gray Bm, Damp
SM
108
6
-_
ative Soils
10
112/22/26
Silty Sand: Gray Brn, Damp
SM
97
6
15
11/15/20
Silty F Sand: Lt Brn, Dry
SM
89
l
-
Recovered Sample
Total Depth = 16.5'
-
I
o Bedrock
20
Unrecoveied Sample
No Groundwater
-
Standard Penetration Sample
25
30
35
40
,
45
A
Note: The stratification lines represent the approximate
-
boundaries between the soil types; the transition may be
50
gradMil.
Sladden Eneincerine
APPENDIX B
1997 UBC Seismic Design Criteria
October 4, 2002
-7- Project No. 544-1274
02-10-614
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 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.
Fault Zone
Approximate Distance
From Site
Fault Type
1997 UBC
San Andreas
9.2 km
A
San Jacinto
34.1 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.
Near -Source
Near -Source
Seismic
Seismic
Seismic
Acceleration
Velocity
Coefficient
Coefficient
Source
Factor, Na
Factor, N,
Ca
C„
San Andreas
1.0
1.25
0.44 N,,
0.64 Nv
San Jacinto
1.0
1.0
0.44 Na
0.64 N,.
Sladden 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
October 29, 2001
Toll Brothers, Inc.
74-923 Hovley Lane East, Suite-2-220
Palm Desert, California 92260
Attention: Mr. Gary Lemon
Project No. 544-1274
01-10-538
Project: Mountainview Country Club
Jefferson Street
La Quinta, California
Subject: Geotechnical Update
Reference: Geotechnical Engineering Report prepared by Buena Engineers, Inc: dated September 6,
•1989, Job No. B7-1645-P 1, Report No. 89-09-703.
As requested, we have reviewed the referenced Geotechnical Engineering Report as it relates to the
design and construction of the proposed residential development. In addition, we have visited the.project
site to observe the present conditions. The project site is located on the east side of Jefferson Street
between Avenue 50 and Avenue 52 in the City of La Quinta, California.
The referenced Geotechnical Engineering Report includes recommendations for remedial site grading
and the design and construction of the proposed residential structure foundations. Based upon our review
of the referenced report and our recent site observations, it is our opinion that the recommendations
included in the referenced Geotechnical Engineering Report remain applicable.
The structural values included in the referenced report should be applicable for use in the design of the
proposed residential structure foundations. Conventional shallow spread footings should be at least 12
inches deep and bottomed into firm compacted soils. Continuous footings at least- 1 foot wide and
isolated pad footings at least 2 feet square may be designed using allowable bearing pressures of 1200
and 1400 pounds per square foot (psf), respectively. Allowable increases of 200 psf for each additional I
foot of width and 300 psf for each additional 6 inches of embedment depth may be utilized. The `
maximum allowable bearing pressure should be 2000 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.
Settlements may result from the anticipated foundation loads. These estimated ultimate settlements are
calculated to be a maximum of I 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.
These elastic settlements are expected to occur during construction.
October 29, 2001 -2- Project No. 544-1274
01-10-538
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
0.49 between soil and concrete may be used for. dead load forces only. A passive earth pressure of 300
Pounds per square foot, per foot of depth, may be used along the sides of footings, that are placed against
properly compacted soils. Passive earth pressure should be ignored within the upper I foot except where
confined (such as beneath a floor slab).
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. Walls should be provided with adequate drainage.
It is our opinion that the remedial grading in the original Geotechnical Engineering Report remain valid.
In general, the remedial grading should include overexcavation and recompaction of the bearing soils
within the proposed building areas.
The building pad areas should be cleared of any surface vegetation and root systems prior to grading.
Building areas should be overexcavated to a depth of at least 3 feet below existing grade or 3 feet below
pad grade, whichever is deeper. The exposed surface should be scarified, moisture conditioned and
compacted to a minimum of 90 percent relative compaction. Fill material may then be placed in thin lifts
at near optimum moisture content and compacted to at least 90 percent relative compaction.
Overexcavation should be confirmed by a representative of Sladden Engineering and compaction should
be verified by testing.
Based upon our recent experience on several nearby projects, it appears that the estimated shrinkage
indicated in the referenced report may be somewhat low. A shrinkage loss of 20 to 25 percent appears
more appropriate. Including clearing losses and subsidence, total losses on the order of 30 to 35 percent
should be expected.
It should be noted that the site is located within a seismically active area of Southern California and it is
likely that the proposed structures will experience strong ground shaking as a result of an earthquake
event along one of the faults in the region during the expected life of the development. As a minimum,
structures should be designed based upon Seismic Zone 4 design criteria included in the Uniform
Building Code (UBC). The potential for liquefaction or other geologic/seismic hazards occurring at the
site is considered to be negligible.
We appreciate the opportunity to provide service to you on this project, if you have any questions
regarding this letter or the referenced report please contact the undersigned.
Respectfully submitted,
SLADDEN ENGINEERING
c
Brett L. Anderson I� Yi
Principal Engineer '
Letter/pc
idU. �• ' �.��ji
i vr_
a-` 0-2f
�'''=ti �• fit,/..
Copies: 2/Toll Brothers, Inc.
4/MDS Consulting
October29, 2001 -3- Project No, 544-1274
01-10-538
1.997 UNIFORM BUILDING CODE INFORMATION
The International Conference of Building Officials 1997 Uniform Building Code contains substantial
revisions and additions to the earthquake engineering section in Chapter 16. 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.
1
Fault Zone
Approximate Distance
From Site
Fault Type
1997 UBC
San Andreas
9.0 km
A
San Jacinto
33 km
A
Based on our field observations and understanding of local geologic conditions, the soil profile type
judged applicable to this site is SD, 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.
Near -Source
Near -Source
Seismic
Seismic
Seismic
Acceleration
Velocity
Coefficient
Coefficient
Source
Factor, Na
Factor, N,,
Ca
Cv
San Andreas
1.05
1.3
0.44 Na
0'.64 N,,
San Jacinto
1.0
1.0
0.44 Na
0.64 N„
Qlnili/in• /%nnini•nrir+n