HomeMy WebLinkAboutCDP 03-49; Brown Residence; Brown Residcence Drainage Study; 2004-07-13DRAINAGE STUDY
KECEIVED
JUl 2 0 ^^^^
ENGINEERING
DEPARTWiEN'i
BROWN RESIDENCE
LOT 119, MAP NO. 3312
CARLSBAD, CA
Report Prepared By: KRH Engineering Inc.
4844 Louise Drive
SanDiego, CA92115
Phone: 619-265-9147
Fax: 619-265-9147
DATE: 07/13/04
Overview:
This drainage study is for the grading ofa single family lot located on the east side ofCarlsbad
Boulevard, two lots south of Cerezo Drive. In the City of Carisbad. The property is currently
vacant. The existing topography is flat and sheet grades toward Carlsbad Boulevard at an
approximate slope of 2.5%. The property is bounded by single family residences on the north, east
and south sides. The properties to the east drain onto and across the site.
The proposed development will constmct a single family residence on the property. All drainage
patterns will continue as they did prior to development. All onsite and offsite flows will be
carried by swales around the residence to Carisbad Boulevard.
The west portion ofthe site will be depressed for an entrance to a subterranean garage and storage
space. Since this area cannot gravity drain, a sump pump system will be installed to collect and
discharge the flow to the swale system on the south side of the residence. The system will have
two pumps. Each pump will be capable of pumping the 100 year storm flow to the swale. The
pumps will altemate each time they are used. For safety, both pumps will operate together in the
case that the water level rises above the 100 year level in the vault. The vault will hold just under
470 gallons of water (volume below the inflow pipe). The time to peak for the 100 year storm is
13.13 minutes, and the peak flow is 28.5 GPM for the area contributing to the pump system. Using
the rational hydrograph method, a volume of 374 gallons will be generated during the 100 year
storm.
Suminary:
The development will not cause any diversion of storm flows.
The pump system is conservatively designed to:
1 carry the 100 year storm with 1 pump
2 has two pumps that will alternate in use.
3 both pumps will work together in the case that the 100 year storm flow is exceeded
4 the volume ofthe vault is greater than the 100 year storm volume for the local basin
AREA CALCULATIONS
Calculations are base on the County of San Diego Design and Procedure Manual.
The 100 year P6 = 2.5
Runoff Coefficient (C) = 0.55 (conservative use of soil type "D")
Time of Concentration: per County Urban Areas Overiand Time of Flow Chart
T = (1.8*(l.l-C)*Length^0.5)/(Slope^(l/3))
Intensity: per San Diego County Appendix XI-B
1= 7.44 * P6 * D ^-.645
100 YEAR STORM ANALYSIS
BROWN RESIDENCE
SINGLE FAMILY RESIDENCE.
P-6=2.5
LONGEST PATH IS FROM "FRONT" OF ADJACENT LOT TO THE EAST.
FLOW WILL TRAVEL FROM THE ADJACENT LOT INTO THE SWALE
ON THE BROWN RESIDENCE AND ULTIMATLY TO CARLSBAD BOULEVARD.
TOTAL DRAINAGE BASIN
area 0.353145 Acres
dist 252 Feet
height 4.32 Feet
slope 1.714286 %
c 0.55
time 13.1313 Minutes
intensity 3.533495 In/hr
flow 0.68631 CFS
Local basin contributing to the pump system
area 0.033 Acres
c 0.55
intensity 3.533495 In/hr (same as total basin)
fiow 0.064133 CFS
28.5 GPM
REFERENCE DOCUMENTS
HYDROLOGY MAP
TOTAL AREA=0.35 AC
C=0.55
HIGH PT= 55
LOW PT= 50.68
LENGTH=252'
SL0PE=a1.7l%
Tc=13.1:3 MIN
-100=3.84 IN/HR
Q-10040.'^4 CFS
AREA iCONTRIBUTING TO
SUMP PUMP=0.03 AC
C=0.55
1-100=3.82 IN/HR
0-100=0.06 CFS
=28.5 GPM
<nivA3finoa avasitivo
TABLE 2
RUNOFF COEFFICIENTS (RATIONAL METHOD)
DEVELOPED AREAS (URBAN)
^^"^ Coefficient. C
Soil Type (1)
Residential: Q
Single Family ,55
.Multi-Units ,70
-Mobile Homes .65
Rural (lots greater than 1/2 acre) A5
Commercial (2)
80% Impervious .85
Industrial (2)
90% Impervious .95
NOTES:
(I) Type D soil to be used for all areas.
(2) Where actual conditions deviate significantly from the tabulated
imperviousness values of 80% or 90%, the values given for coefficient C,
may be revised by multiplying 80% or 90% by the ratio of actual
imperviousness to the tabulated imperviousness. However, in no case shall
the final coefficient be less than 0.50. For example: Consider commercial
property on D soil.
Actual imperviousness = 50%
Tabulated imperviousness = 80%
Revised C = |^ x 0.85 = 0.53
82
URBAM 'AREAS OvtRLAND
TIME OF FLOW CURVES
O
I
c
— —'-T—I* ^'?-|'t^
l,t(l.i-C)V^
'Use Formulo For
rtu::" Disionces m Eicess:;;7:":::*."T
:: 7:.;-:*.:;•: :!.T r.u:;i":i
.,. _ — . _ J 1.., r
z
z
Surfoc* Flow Tim* Curvai
£XAKA?LE. t
GlVEM '. L-BAiGTH FLOW « 4c>0 FT.
86
mmmmmii^l9mmmmmmm
ri771"'77riTf/Tf7TTi.7rii i-ii MJH llll.iii.ii.iiimirr:. • . .' i 'i.i.^.i ti iHirr; rlTn i
Equation: 7.44 -.645
Intensity (In./Hr.)
6 Hr, Precipitation
^10 15 20
Minutes
30 40 50 1 2 . 3
Hours
Directions for Application: \
1) From precipitation naps detennine 6 hr. and \
24 hr. amounts for the selected frequency.
These maps are printed in the County Hydrology
Manual (10, 50 and 100 yr. maps included in the
Design and Procedure Manual).
2) Adjust 6 hr. precipitation (if necessary) so
that it is within the range of 45% to 65% of
the 24 hr. precipitation. (Not applicable
to Desert)
3) Plot 5 hr. precipitation on the right side'
of the chart.
4) Drav/ a line through the point parallel to the
plotted lines.
5) This line is the intensity-duration curve for
the location being analyzed.
Application Form:
0) Selected Frequency yr.
1) ^6 = Jn., P24=
2) Adjusted *Pg=
3) t^ = mm.
4)
P24
in.
%*
I =
*Not Applicable to Desert Region
APPENDIX XI
IV-A-14
Revised 1/85
DEPARTMENT OF SANITATION &
FLOOD COrJTROL 100-YEAR B-HOUa PRECIPITATIQ?!
ISOPLUVIALS OF lOO-YEAR 6-HOUR
priECiPiTATion m unus o? AM I::CII
Prepn
U.S. DEPARTMEN
NATIONAL OCEANIC AND ATsJoSPHERlC ADMINISTRATION
SPECIAL STUDIES BRANCH, OFFICE OF II
30' 15' 116'
Revised 1/85 APPENDIX XI-F.
OEPARTMENT OF SANITATION S-
FLOOO CONTROL
33'
30'
15'
Prep
U.S. DEPARTMEN
NATIONAL OCEANIC AND AT
SPECIAL STUDIES bKA.NCll, OKFICE OF M
30'
ClPlTATlUn
20-/ISOPLUVIALS OF 100 -YEAR 24-HOUR
PRECIPITATION IM ENTHS OF AN INCH
'l'i' 30' 117° 10' |f;« Iir,"
Revi.sed 1/85 APPENDIX XI-H
EARTHWORK ESTIMATE
BROWN RESIDENCE
CUT
EL
FT
APPROX AREA = 3130 SF
AREA
52.75
52.5
52
51
50
49.5
49.29
49
SF
51
844
1035
2478
1748
575
191
VOL
CF
6.375
223.75
939.5
3322
1056.5
243.915
111.07
5903.11
218.6337
TOTAL VOL (CF)
TOTAL VOL CY
ADDITIONAL CUT VOLUME FOR SLABS
PER SOILS REPORT, SLAB SECTION = 6"
VOLUME = 1565 CF = 58 CY
FILL
EL
FT
50.5
51
52
53
54
54.5
AREA
SF
29
484
290
829
1110
SHRINKAGE
PER SOILS REPOR
VOL
CF
-7.25
-256.5
-387
-559.5
-484.75
-1695
-62.7778
GRADING PLAN FOR
BROWN RESIDENCE
CDP 03-49
DWG NO. 422-5A
Estimate Prepared By:
KRH Engineering, Inc
4844 Louise Drive
San Diego, CA92115
TOTAL VOL (CF)
TOTAL VOL CY
• BUILDING ENVELOPE PLUS 5' AROUND BUILDING
TO BE RECOMPACTED TO A MINIMUM DEPTH OF 3' BELOW GRADE.
BUILDING AREA PLUS 5" AROUND = 4,343 SF
VOLUME AT 3' DEPTH = 13029 CF
ASSUME 20% SHRINKAGE
SHRINKAGE = 2606 CF = 97 CY
d z
o tu
X
o
EARTHWORK ESTIMATE
BROWN RESIDENCE CHI VI:
CUT
EL AREA VOL U
FT SF CF MG
52.75 0 t KI
52.5 51 6.375
52 844 223.75
51 1035 939.5
50 2478 3322
49.5 1748 1056.5
49.29 575 243.915
49 191 111.07
5903.11 TOTAL VOL (CF)
218.6337 TOTAL VOL CY
ADDITION AL CUT VOLUME FOR SLABS
APPROX AREA = 3130 SF
PER SOILS REPORT, SLAB SECTION = 6"
VOLUME = 1565 CF = 58 CY
FILL
EL AREA VOL
FT SF CF
50.5 0
51 29 -7.25
52 484 -256.5
53 290 -387
54 829 -559.5
54.5 1110 -484.75
-1695 TOTAL VOL (CF)
-62.7778 TOTAL VOL CY
SHRINKA GE
PFR .«^nil .q RFPORT BUILDING ENVELOPE PLUS 5' AROUND BUILDING
Tn RF RFCOMPACTED TO A MINIMUM DEPTH OF 3' BELOW GRADE.
BUILDINC 3 AREA PLUS 5' AROUND = 4,343 SF
VOLUME AT 3' DEP TH = 13029 CF
ASSUME 20% SHRINKAGE
SHRINKA .GE = 2606 CF = 97 CY
1 1 1
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DRAINAGE STUDY
BROWN RESIDENCE
LOT 119, MAP NO. 3312
CARLSBAD, CA
Report Prepared By: KRH Engineering Inc.
4844 Louise Drive
San Diego, CA92115
Phone: 619-265-9147
Fax: 619-265-9147
DATE: 07/13/04
COP 02'
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Overview:
This drainage study is for the grading ofa single family lot located on the east side ofCarlsbad
Boulevard, two lots south of Cerezo Drive. In the City of Carisbad. The property is currently
vacant. The existing topography is flat and sheet grades toward Carlsbad Boulevard at an
approximate slope of 2.5%. The property is bounded by single family residences on the north, east
and south sides. The properties to the east drain onto and across the site.
The proposed development will construct a single family residence on the property. All drainage
pattems will continue as they did prior to development. All onsite and offsite flows will be
carried by swales around the residence to Carisbad Boulevard.
The west portion ofthe site will be depressed for an entrance to a subterranean garage and storage
space. Since this area cannot gravity drain, a sump pump system will be installed to collect and
discharge the flow to the swale system on the south side of the residence. The system will have
two pumps. Each pump will be capable of pumping the 100 year storm flow to the swale. The
pumps will altemate each time they are used. For safety, both pumps will operate together in the
case that the water level rises above the 100 year level in the vault. The vault will hold just under
470 gallons of water (volume below the inflow pipe). The time to peak for the 100 year storm is
13.13 minutes, and the peak flow is 28.5 GPM for the area contributing to the pump system. Using
the rational hydrograph method, a volume of 374 gallons will be generated during the 100 year
storm.
Suminary:
The development will not cause any diversion of storm flows.
The pump system is conservatively designed to:
1 carry the 100 year storm with 1 pump
2 has two pumps that will altemate in use.
3 both pumps will work together in the case that the 100 year storm flow is exceeded
4 the volume ofthe vault is greater than the 100 year storm volume for the local basin
AREA CALCULATIONS
Calculations are base on the County of San Diego Design and Procedure Manual.
The 100 year P6 = 2.5
Runoff Coefficient (C) = 0.55 (conservative use of soil type "D")
Time of Concentration: per County Urban Areas Overiand Time of Flow Chart
T = (1.8*(l.l-C)*Length^0.5)/(Slope^(l/3))
Intensity: per San Diego County Appendix XI-B
1= 7 44 * P6 * D ^-.645
100 YEAR STORM ANALYSIS
BROWN RESIDENCE
SINGLE FAMILY RESIDENCE.
P-6=2.5
LONGEST PATH IS FROM "FRONT" OF ADJACENT LOT TO THE EAST.
FLOW WILL TRAVEL FROM THE ADJACENT LOT INTO THE SWALE
ON THE BROWN RESIDENCE AND ULTIMATLY TO CARLSBAD BOULEVARD.
TOTAL DRAINAGE BASIN
area 0.353145 Acres
dist 252 Feet
height 4.32 Feet
slope 1.714286 %
c 0.55
time 13.1313 Minutes
intensity 3.533495 In/hr
flow 0.68631 CFS
Local basin contributing to the pump system
area 0.033 Acres
c 0.55
intensity 3.533495 In/hr (same as total basin)
flow 0.064133 CFS
28.5 GPM
REFERENCE DOCUMENTS
HYDROLOGY MAP
TOTAL AREA=0.35 AC
0=0.55
HIGH PT= 55
LOW PT= 50.68
LENGTH=252'
SL0PE=a1.7l%
Tc=13.113 MIN
1-100=3.84 IN/HR
Q-100=0.7H CFS
AREA CONTRIBUTING TO
SUMP PUMP=0.03 AC
0=0.55
1-100=3.82 IN/HR
0-100=0.06 CFS
=28.5 GPM
ouvAsrinoa avasiuvo
TABLE 2
RUNOFF COEFFICIENTS (RATIONAL METHOD)
DEVELOPED AREAS (URBAN)
^^"^ ^se Coefficient. C
Soil Type (1)
Residential: Q
Single Family ,55
.Multi-Units .70
-Mobile Homes .65
Rural (lots greater than 1/2 acre) A5
Commercial (2)
80% Impervious .85
Industrial (2)
90% Impervious .95
NOTES:
(1) Type D soii to be used for all areas.
(2) Where actual conditions deviate significantly from the tabulated
imperviousness values of 80% or 90%, the values given for coefficient C,
may be revised by multiplying 80% or 90% by the ratio of actual
imperviousness to the tabulated imperviousness. However, in no case shall
the final coefficient be less than 0.50. For example: Consider commercial
property on D soil.
Actual imperviousness = 50%
Tabulated imperviousness = 80%
Revised C = |^ x 0.85 = 0.53
82
URBAM ^ARLAS OvtRLANiD
T\ML OF FLOW CURVES
s
IOO
700
<00
300
-.^V-j^--^.^ r-*— ^
rtl.:-:r~ 0's'o"c«fs i'> £icess:':7:~:*:r."T
- 400
300
200
100
• Use Formulo For Z. 80
70
40
50
40 £
Z
i
30
2C
10
Svrfac* Flow Tim* Cwrv«
£XAK^?LE. t
6>JVEM uE^/^GTH c^F FLOW * 4c>o FT.
86
.Ta.^ - tt-i-j!^ '^^S
' Tl'r 7 pTffTfTTT7.Tr/ i' H I MIM1111.1II. I j. I iitrn rr?!
Equation:
uiu.i Ll in innhni -.645 I •••= 7.44 P^ D' o
I » Intensity (In./Hr.)
Pg = 6 Hr, Precipitation
D = Duration
15 20
Minutes
40 50 1
nn>'';it'f nn
2
Hours
Directions for Application: \
1) From precipitation naps determine 6 hr. and |
24 hr. amounts for the selected frequency.
These maps are printed in the County Hydrology
Manual (10, 50 and 100 yr. maps included in the
Design and Procedure Manual).
2) Adjust 6 hr. precipitation (if necessary) so
that it is within the range of 45% to 65% of
the 24 hr. precipitation. (Not applicable
to Desert)
3) Plot 6 hr. precipitation on the right side^
of the chart.
4) Drav/ a line through the point parallel to the
plotted lines.
5) This line is the intensity-duration curve for
the location being analyzed.
Application Form:
0) Selected Frequency yr.
1) ^6 = Jn., P24=
2) Adjusted *Pg= in.
%*
3)
4)
^c =
I =
min.
In/hr.
*Not Applicable to Desert Region
APPENDIX XI
IV-A-14
Revised 1/85
DEPARTMENT OF SANITATION S
FLOOD co^rrROL lOO-YEAR 6-HOUll PRECIPITATiQJl
ISOPLUVIALS
PfiECiFiTATIOn m
OF 100-YFAR 6-HOUR
em;s G? AH I::CSI
33'
U.S. DEPARTMEN
NATIONAL OCEANIC AND ATuJoSPIlEHIC ADMINISTRATION
SPECIAL STUDIES BRANCH, OFFICE OF II
Revised 1/85 APPENDIX XI-E
DEPARTMENT OF SANITATION S-
FLOOD CONTROL
^5
33"
30'
15'
^5'
U.S. DEPARTMEN
NATIONAL OCtANIC ANO AT\
SPECIAL STUDIES bKANCll, OKKlCli OF 11'
[CIPITATIUM
"20-^ ISOPLUVIALS OF 100 -YEAR 24-HOUR
PRECIPITATIOn IN EMTUS OF AN INCH
30'
'l'i" 30' 11' 117° ''!«' 10' jfj' nr."
Revised 1/85 APPENDIX XI-H
&OAST GEOTECHNIciP
CONSIILTINC F,N(UNEEKS ANU (lEOLOCilSTS
June 3, 2003
Laveme and Elaine Brown ^ nu,y
5411 Los Robles Drive JUL 2 U ^JJ^
Carlsbad, CA 92008 ^^o.Kir,
HNGINEEWNG
DEPARTMENT
Subject: RESPONSE TO CITY OF CARLSBAD PLANNING DEPARTMENT LETTER
Dated May 21, 2002
CDP 02-19-Brown Family Residence
Reference: PRELIMINARY GEOTECHNICAL INVESTIGATION
Proposed Single Family Residence
Lot 119, Map No. 3312
Vacant Lot, Carlsbad Boulevard
APN 210-115-24
Carlsbad, Califomia
Prepared by Coast Geotechnical
Dated April 15, 2002
Dear Mr. and Mrs. Brown:
In reference to the city of Carlsbad subject letter. Item 1, regarding surface drainage
directed along the narrow side yard area, the following conclusions and
recommendations are presented.
y
z
CONCLUSIONS AND RECOMMENDATION.S
1) Infiltration of water adjacent to foundations and retaining walls can potentially
adversely affect conventional footings and create "damp" conditions in \^
mJkai
subterranean structures. The following recommendations are intended to reduce
these concems.
<
779 ACADEMY DRIVE • SOLANA BEACH. CALIFORNIA 92075 "-"i
755-8(i22 • FAX (858) 7.55-9126 f7U fH
Coast Geotechnical June 3, 2003
W.O. P-357032
Page 2
2) The six (6) foot wide northern side yard area will slope to the west at a grade of
about three (3) percent. The upper 12 inches of the subgrade deposits in the side
yard area should be scarified and compacted to a minimum of 95 percent of the
laboratory maximum dry density.
3) A portion of the residence adjacent to the side yard area will be supported on
conventional footings. These footings should be deepened an additional six (6)
inches.
4) Positive drainage should be maintained along the side yard area.
If you have any questions, please do not hesitate to contact us at (858) 755-8622. This
opportunity to be of service is appreciated.
Respectfully submitted,
COAST GEOTECHNICAL
Mark Burwell, C.E.G.
Engineering Geologist
ft)AST GEOTECHNICi^
CONSULTINO ENOINEERS AND OKOLCKHSTS
April 15, 2002
Laveme and Elaine Brown
5411 Los Robles Drive
Carlsbad, CA 92008
-•••AG
RE: PRELIMINARY GEOTECHNICAL INVESTIGATION
Proposed Single Family Residence
Lot 119, Map No. 3312
Vacant Lot, Carlsbad Boulevard
APN 210-115-24
Carlsbad, California
Dear Mr. and Mrs. Brown:
In response to your request and in accordance with our Proposal and Agreement dated
March 14, 2002, we have performed a preliminary geotechnical investigation on the
subject site for the proposed residence. The findings of the investigation, laboratory test
results and recommendations for foundation design and site development are presented
in this report.
From a geologic and soils engineering point of view, it is our opinion that the site is
suitable for the proposed development, provided the recommendations in this report are
implemented during the design and constmction phases.
If you have any questions, please do not hesitate to contact us at (858) 755-8622. This
opportunity to be of service is appreciated.
Respectfully submitted,
COAST GEOTECHNICAL
Mark Burwell, C.E.G. Vithaya Singhanet, P.E.
Engineering Geologist Geotechnical Engineer
^79 ACADEMY DRIVI-: • S(.)iANA BEACH. CALIFORNIA 9207
(858) 755-8(22 • I-AX (858) 755-912(i
PRELIMINARY GEOTECHNICAL INVESTIGATION
Proposed Single Family Residence
Lot 119, Map No. 3312
Vacant Lot, Carlsbad Boulevard
APN 210-115-24
Carlsbad, Califomia
Prepared For:
Laverne and Elaine Brown
5411 Los Robles Drive
Carlsbad, CA 92008
April 15, 2002
* W.O. P-357032
Prepared By:
COAST GEOTECHNICAL
779 Academy Drive
Solana Beach, Califomia 92075
TABLE OF CONTENTS
VICINITY MAP
INTRODUCTION 5
SITE CONDITIONS 5
PROPOSED ADDITION 5
SITE INVESTIGATION 6
LABORATORY TESTING 6
GEOLOGIC CONDITIONS 7
CONCLUSIONS 10
RECOMMENDATIONS 11
A. BUILDING PAD-REMOVALS/RECOMPACTION 11
B. TEMPORARY SLOPES/EXCAVATION CHARACTERISTICS 12
C. FOUNDATIONS 12
D. SLABS ON GRADE (INTERIOR AND EXTERIOR) 13
E. RETAINING WALLS 14
F. SETTLEMENT CHARACTERISTICS 14
G. SEISMIC CONSIDERATIONS 14
H. SEISMIC DESIGN PARAMETERS 15
I. UTILITY TRENCH 15
J. DRAINAGE 16
K. GEOTECHNICAL OBSERVATIONS 16
L. PLAN REVIEW 17
LIMITATIONS 17
REFERENCES 19
APPENDICES
APPENDIX A LABORATORY TEST RESULTS
EXPLORATORY BORING LOGS
GRADING PLAN
APPENDIX B REGIONAL FAULT MAP
SEISMIC DESIGN PARAMETERS
DESIGN RESPONSE SPECTRUM
APPENDIX C GRADING GUIDELINES
CTopyrisht ® 2000 [DeLorme. XopoTools AdvAnced Print Kit XE. Scal«: 1 : 7,200 Zoom Level: 14-7 Datum: WGS84
Coast Geotechnical April 15, 2002
W.O. P-357032
Page 5
INTRODUCTION
This report presents the results of our geotechnical investigation on the subject property.
The purpose of this study is to evaluate the nature and characteristics of the earth
materials underlying the property, the engineering properties ofthe surficial deposits and
their influence on the proposed residence.
SITE CONDITIONS
The subject property is located just south of Cerezo Drive, along the east side ofCarlsbad
Boulevard, in the city of Carlsbad. The site includes a vacant rectangular lot that slopes
very gently to the west. Relief on the site is approximately 3.0 vertical feet. The property
is bounded along the north, south and east by developed residential lots.
Vegetation includes a sparse to moderate growth of ice plant, shmbs and cactus.
Drainage is by sheet flow to the west.
PROPOSED ADDITION
Preliminary grading and building plans for development of the site were prepared by
Grabhorn Engineering and DZN Partners Architecture, respectively. The project includes
constmction of a new two story residence over a proposed basement. Grading will
include excavation up to 4.0 vertical feet for the basement.
Coast Geotechnical April 15, 2002
W.O. P-357032
Page 7
percentage of the dry unit weight. Both are shown on the enclosed Laboratory Tests
Results and Exploratory Logs.
Maximum Dry Densitv and Optimum Moisture Content
The maximum dry density and optimum moisture content were determined for selected
samples of earth materials taken from the site. The laboratory standard tests were in
accordance with ASTM D-1557-91. The results of the tests are presented in the
Laboratory Test Results.
GEOLOGIC CONDITIONS
The subject property is located in the Coastal Plains Physiographic Province of San Diego.
The property is underlain at relatively shallow depths by Pleistocene terrace deposits.
The terrace deposits are underlain at depth by Eocene-age sedimentary rocks which have
commonly been designated as the Santiago Formation on published geologic maps. The
terrace deposits are covered by thin residual soil deposits. A brief description of the
earth materials encountered on the site follows.
Artificial Fill
No evidence of significant fill deposits were encountered in the exploratory borings. A
small mound, approximately 2.0 feet high, of stockpiled sandy deposits with concrete
fragments and roots was observed in the northeastem portion of the site.
Coast Geotechnical April 15, 2002
W.O. P-357032
Page 8
Residual Soil
Site exploration suggests the underlying terrace deposits are blanketed by approximately
3.0 to 6.0 inches of brown silty sand. The soil is generally dry and loose, as encountered
in the exploratory borings. The contact with the underlying terrace deposits is
gradational and may vary across the site.
Terrace Deposits
Underlying the surficial materials, poorly consolidated Pleistocene terrace deposits are
present. The sediments are composed of tan to reddish brown fine and medium-grained
sand. The terrace deposits are dry to an approximate depth of 12 feet where a slight
increase in moisture was observed. Regionally, the Pleistocene sands are considered flat-
lying and are underlain at depth by Eocene-age sedimentary rock units.
Expansive Soil
Based on our experience in the area and previous laboratory testing of selected samples,
the residual soil and Pleistocene sands reflect an expansion potential in the low range.
Ground Water
No evidence of perched or high ground water tables were encountered to the depth
explored. However, it should be noted that seepage problems can develop after
completion of constmction. These seepage problems most often result from drainage
Coast Geotechnical April 15, 2002
W.O. P-357032
Page 9
alterations, landscaping and over-irrigation. In the event that seepage or saturated
ground does occur, it has been our experience that they are most effectively handled on
an individual basis.
Tectonic Setting
The site is located within the seismically active southern California region which is
generally characterized by northwest trending Quatemary-age fault zones. Several of
these fault zones and fault segments are classified as active by the California Division of
Mines and Geology (Alquist-Priolo Earthquake Fault Zoning Act).
Based on a review of published geologic maps, no known faults transverse the site. The
nearest active fault is the offshore Rose Canyon Fault Zone located approximately 3.9
miles west ofthe site. It should be noted that the Rose Canyon Fault is not a continuous,
well-defined feature but rather a zone of right stepping en echelon faults. The complex
series of faults has been referred to as the Offshore Zone of Deformation (Woodward-
Clyde, 1979) and is not fully understood. Several studies suggest that the Newport-
Inglewood and the Rose Canyon faults are a continuous zone of en echelon faults
(Treiman, 1984). Further studies along the complex offshore zone of faulting may
indicate a potentially greater seismic risk than current data suggests. Other faults which
could affect the site include the Coronado Bank, Elsinore, San Jacinto and San Andreas
Faults. The proximity of major faults to the site and site parameters are shown on the
enclosed Seismic Design Parameters.
Coast Geotechnical April 15, 2002
W.O. P-357032
Page 10
Liquefaction Potential
Liquefaction is a process by which a sand mass loses its shearing strength completely and
flows. The temporary transformation of the material into a fluid mass is often associated
with ground motion resulting from an earthquake.
Owing to the moderately dense nature of the Pleistocene terrace deposits and the
anticipated depth to ground water, the potential for seismically induced liquefaction and
soil instability is considered low.
CONCLUSIONS
1) The subject property is located approximately 300 lateral feet east of the coastal
bluffs and is relatively free of potential geologic hazards such as landsliding,
Uquefaction, high ground water conditions and seismically induced subsidence.
2) The existing soil and dry terrace deposits are not suitable for the support of
proposed footings and concrete flatwork in their present condition. These
surficial deposits should be removed in the upper 3 0 feet and replaced as
properly compacted fill deposits in areas which will support footings and concrete
flatwork outside the proposed basement walls.
3) It is anticipated that the basement excavation will expose terrace deposits.
Coast Geotechnical April 15, 2002
W.O. P-357032
Page 11
However, if dry and loose materials are encountered in the area of the proposed
basement slab they should be compacted. All retaining waU footings should be
founded the design depth into competent terrace deposits.
RECOMMENDATIONS
Building Pad-Removals/Recompaction
In foundation and slab areas outside the proposed basement walls, the existing soil and
weathered terrace deposits should be removed to a minimum depth of 3.0 feet below the
existing grade or 18 inches below the base of proposed footings, whichever is greater,
and replaced as properly compacted flfl. Removals should include the entire building
pad extending a minimum of 5.0 feet beyond the building footprint, where appUcable.
Most of the existing earth deposits are generally suitable for reuse, provided they are
cleared of afl vegetation, debris and thoroughly mixed. Prior to placement of fifl, the base
of the removal should be observed by a representative of this firm. Additional
overexcavation and recommendations may be necessary at that time. The exposed
bottom should be scarified to a minimum depth of 6.0 inches, moistened as required and
compacted to a minimum of 90 percent of the laboratory maximum dry density. Fill
should be placed in 6.0 to 8.0 inch Ufts, moistened to approximately 1.0 - 2.0 percent
above optimum moisture content and compacted to a minimum of 90 percent of the
laboratory maximum dry density. Soil and weathered terrace deposits in areas of
proposed concrete flatwork and driveways should be removed and replaced as properly
Coast Geotechnical April 15, 2002
W.O. P-357032
Page 13
For design purposes, an allowable bearing value of 1500 pounds per square foot may be
used for foundations at the recommended footing depths. The bearing value may be
increased to 2000 pounds per square foot for subterranean retaining wall footings.
The bearing value indicated above is for the total dead and frequently applied live loads.
This value may be increased by 33 percent for short durations of loading, including the
effects of wind and seismic forces.
Resistance to lateral load may be provided by friction acting at the base of foundations
and by passive earth pressure. A coefficient of friction of 0.35 may be used with dead-
load forces. A passive earth pressure of 250 pounds per square foot, per foot of depth
of fifl penetrated to a maximum of 1500 pounds per square foot may be used.
Slabs on Grade (Interior and Exterior)
Slabs on grade should be a minimum of 4.0 inches thick and reinforced in both
directions with No. 3 bars placed 18 inches on center in both directions. The slab should
be underlain by a minimum 2.0-inch sand blanket. Where moisture sensitive floors are
used, a minimum 6.0-mil Visqueen or equivalent moisture barrier should be placed over
the sand blanket and covered by an additional two inches of sand. Utility trenches
underlying the slab may be backfilled with on-site materials, compacted to a minimum
of 90 percent of the laboratory maximum dry density. Slabs including exterior concrete
flatwork should be reinforced as indicated above and provided with saw cuts/expansion
Coast Geotechnical April 15, 2002
W.O. P-357032
Page 14
joints, as recommended by the project stmctural engineer. All slabs should be cast over
dense compacted subgrades.
Retaining Walls
Cantilever walls (yielding) retaining nonexpansive granular soils may be designed for an
active-equivalent fluid pressure of 35 pounds per cubic foot. Restrained walls
(nonyielding) should be designed for an "at-rest" equivalent fluid pressure of 58 pounds
per cubic foot. Wall footings should be designed in accordance with the foundation
design recommendations. All retaining walls should be provided with an adequate
backdrainage system (Miradrain 6000 or equivalent is suggested). The soil parameters
assume a level granular backfill compacted to a minimum of 90 percent of the laboratory
maximum dry density.
Settlement Characteristics
Estimated total and differential settlement is expected to be on the order of 3/4 inch and
1/2 inch, respectively. It should also be noted that long term secondary settlement due
to irrigation and loads imposed by stmctures is anticipated to be 1/4 inch.
Seismic Considerations
Although the Ukelihood of ground mpture on the site is remote, the property wiU be
exposed to moderate to high levels of ground motion resulting from the release of energy
Coast Geotechnical April 15, 2002
W.O. P-357032
Page 15
should an earthquake occur along the numerous known and unknown faults in the
region.
The Rose Canyon Fault Zone is the nearest known active fault and is considered the
design earthquake for the site. A maximum probable event along the offshore segment
of the Rose Canyon Fault is expected to produce a peak bedrock horizontal acceleration
of 0.39g and a repeatable ground acceleration of 0.25g.
Seismic Design Parameters (1997 Uniform Building Code)
Soil Profile Type - S^
Seismic Zone - 4
Seismic Source - Type B
Near Source Factor (NJ - 1.1
Near source Acceleration Factor (NJ - 1.0
Seismic Coefficients
C, = 0.40
C, = 0.64
Design Response Spectmm
T, = 0.643
T„ = 0.129
Utilitv Trench
We recommend that all utilities be bedded in clean sand to at least one foot above the
top of the conduit. The bedding should be flooded in place to fill aU the voids around
the conduit. Imported or on-site granular material compacted to at least 90 percent
relative compaction may be utilized for backfill above the bedding.
Coast Geotechnical April 15, 2002
W.O. P-357032
Page 17
Plan Review
A copy of the final plans should be submitted to this office for review prior to the
initiation of constmction. Additional recommendations may be necessary at that time.
LIMITATIONS
This report is presented with the provision that it is the responsibiUty of the owner or the
owner's representative to bring the information and recommendations given herein to
the attention of the project's architects and/or engineers so that they may be incorporated
into plans.
If conditions encountered during constmction appear to differ from those described in
this report, our office should be notified so that we may consider whether modifications
are needed. No responsibility for constmction compliance with design concepts,
specifications or recommendations given in this report is assumed unless on-site review
is performed during the course of constmction.
The subsurface conditions, excavation characteristics and geologic stmcture described
herein are based on individual exploratory excavations made on the subject property.
The subsurface conditions, excavation characteristics and geologic stmcture discussed
should in no way be constmed to reflect any variations which may occur among the
exploratory excavations.
Coast Geotechnical April 15, 2002
W.O. P-357032
Page 18
Please note that fluctuations in the level of ground water may occur due to variations in
rainfall, temperature and other factors not evident at the time measurements were made
and reported herein. Coast Geotechnical assumes no responsibility for variations which
may occur across the site.
The conclusions and recommendations of this report apply as of the current date. In
time, however, changes can occur on a property whether caused by acts of man or nature
on this or adjoining properties. Additionally, changes in professional standards may be
brought about by legislation or the expansion of knowledge. Consequently, the
conclusions and recommendations of this report may be rendered wholly or partially
invalid by events beyond our control. This report is therefore subject to review and
should not be reUed upon after the passage of two years.
The professional judgments presented herein are founded partly on our assessment of
the technical data gathered, partly on our understanding of the proposed constmction
and partly on our general experience in the geotechnical field. However, in no respect
do we guarantee the outcome of the project.
Coast Geotechnical April 15, 2002
W.O. P-357032
Page 19
REFERENCES
1. Hays, Walter W., 1980, Procedures for Estimating Earthquake Ground Motions,
Geological Survey Professional Paper 1114, 77 pages.
2. Petersen, Mark D. and others (DMG), Frankel, Arthur D. and others (USGS), 1996,
Probabilistic Seismic Hazard Assessment for the State of Califomia,
CaUfomia Division of Mines and Geology OFR 96-08, United States
Geological Survey OFR 96-706.
3. Seed, H.B., and Idriss, I.M., 1970, A SimpUfied Procedure for Evaluating Soil
Liquefaction Potential: Earthquake Engineering Research Center.
4. Tan, S.S., and Giffen, D.G., 1995, LandsUde Hazards in the Northern Part of the
San Diego Metropolitan Area, San Diego County, Plate 35A, Open-File
Report 95-04, Map Scale 1:24,000.
5. Treiman, J.A., 1984, The Rose Canyon Fault Zone, A Review and Analysis,
CaUfomia Division of Mines and Geology.
MAPS/AERIAL PHOTOGRAPHS
1. Aerial Photograph, 1982, Foto-Map D-8, Scale 1"=2000'.
2. California Division of Mines and Geology, 1994, Fault Activity Map of Califomia,
Scale 1"=750,000'.
3. Geologic Map of the Oceanside, San Luis Rey and San Marcos 7.5' Quadrangles,
1996, DMG Open File Report 96-02.
4. Grabhorn Engineering, 2002, Concept Grading Plan, Brown Residence, Scale
1"=8'.
5. U.S.G.S., 7.5 Minute Quadrangle Topographic Map, Digitized, Scale Variable.
APPENDIX A
LABORATORY TEST RESULTS
TABLE I
Maximum Dry Density and Optimum Moisture Content
(Laboratory Standard ASTM D-1557-91)
Sample Max. Dry Optimum
Location Density Moisture Content
(pcf)
B-1 @ 1. 0' -3.0• 128.6 10.1
TABLE II
Field Dry Density and Moisture Content
Sample Field Dry Field Mois
Location Density Content
(pcf) %
B-1 @ 1.0' 109 .1 3 .6
B-1 @ 2.0' 96.4 3 .3
B-1 @ 3.5' 94 .1 4.1
B-1 @ 8.0' 105.4 4 .4
B-1 @ 11.0' 112 .2 6 . 6
B-1 @ 15.0' Sample Disturbed 7.1
B-2 @ 2.5' 96 .1 3 .4 B-2 @ 3.5' 104 . 8 3 . 5
B-2 @ 7.0' 107 .1 3.2
B-2 @ 9.0' Sample Disturbed 4 . 5
B-3 @ 2.0' 94 .1 3.4
B-3 @ 5.0' Sample Disturbed 4.6
B-3 (37.0' Sample Disturbed 4.5
P-357032
LOG OF EXPLORATORY BOANG NO. 1
DRILL RIG: PORTABLE BUCKET AUGER
BORING DIAMETER: 3.5"
SURFACE ELEV.: 51.5'
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109.1
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PROJECT NO. P-357032
DATE DRILLED: 03-29-02
LOGGED BY: MB
GEOLOGIC DESCRIPTION
SOIL (Qs): Bm.silty and fine-grained sand, dry, loose
TERRACE DEPOSITS (Qt): Tan to Reddish bm., fine and med.-grained
sand, dry, dense
From 12', increase in moisture
End of Boring @ 16.5'
COAST GEOTECHNICAL
LOG OF EX«LORATORY BO ANG NO. 2
DRILL RIG: PORTABLE BUCKET AUGER
BORING DIAMETER: 3.5"
SURFACE ELEV.: 52'
H
S
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96.1
104.8
107.1
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SHEET 1 OF 1
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PROJECT NO. P-357032
DATE DRILLED: 03-29-02
LOGGED BY: MB
SM
SM
GEOLOGIC DESCRIPTION
SOIL (Qs): Bm.silty and fine-grained sand, dry, loose
TERRACE DEPOSITS (Qt): Tan to Reddish bm., fine and med.-grained
sand, dry, dense
EndofBoring@9.5'
COAST GEOTECHNICAL
LOG OF EXfcORATORY BOANG NO. 3
DRILL RIG: PORTABLE BUCKET AUGER
BORING DIAMETER: 3.5"
SURFACE ELEV.: 52.5'
V '
00
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Pi Q
Pi w
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52.50
0.00 :l«l«i
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PROJECT NO. P-357032
DATE DRILLED: 03-29-02
LOGGED BY: MB
GEOLOGIC DESCRIPTION
94.1 3.4
4.6
4.5
I
— 1.00
50.50
T3 (U
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2.00
49.50
3.00
48.50
4.00
47.50
5.00
46.50
— 6.00
45.50
7.00
44.50
8.00
— 43.50
SHEET 1 OF 1 "9W
nivjwiRiw r.v»W0M
SOIL (Qs): Bm.silty and fme-grained sand, dry, loose
TERRACE DEPOSITS (Qt): Tan to Reddish bm., fine and med.-grained
sand, dry, dense
EndofBoring(@9'
COAST GEOTECHNICAL
Ed
P o ca o < ea
tn
Ct < u
[51.07] 00 -f/- PER DWG NO 3J1--7
[50.58] .S4-f69-t-/- PER DWG NO 331-7
PORTION OF GRADING PLAN
LEGEND
BORING LOCATION (approx.) 1.
COAST GEOTECHNICAL
P-357032 GRAPHIC SCALE
APPENDIX B
CALIFORNIA FAULT MAP
BROWN
1100
1000
-100
900 --
800 --
700 --
600 --
500
400 --
300 --
200 --
100 --
-400 -300 -200 -100 100 200 300 400 500 600
***********************
* *
* UBCSEIS *
* *
* Version 1.03 *
* *
***********************
COMPUTATION OF 1997
UNIFORM BUILDING CODE
SEISMIC DESIGN PARAMETERS
JOB NUMBER: P-357032
JOB NAME: BROWN
FAULT-DATA-FILE NAME: CDMGUBCR.DAT
DATE: 04-12-2002
SITE COORDINATES:
SITE LATITUDE: 33.1284
SITE LONGITUDE: 117.3323
UBC SEISMIC ZONE: 0.4
UBC SOIL PROFILE TYPE: SC
NEAREST TYPE A FAULT:
NAME: ELSINORE-JULIAN
DISTANCE: 40.6 km
NEAREST TYPE B FAULT:
NAME: ROSE CANYON
DISTANCE: 6.3 km
NEAREST TYPE C FAULT:
NAME:
DISTANCE: 99999.0 km
SELECTED UBC SEISMIC COEFFICIENTS;
Na: 1.0
Nv: 1.1
Ca: 0.40
Cv: 0.64
Ts: 0.643
To: 0.129
SUMMARY OF FAULT PARAMETERS
Page
-
APPROX. SOURCE MAX. SLIP FAUL
ABBREVIATED DISTANCE TYPE MAG. RATE TYP
FAULT NAME (km) (A,B,C) (Mw) (mm/yr)
1(SS,DS,BT)
======= ________
SAN GABRIEL 159.0 B 7.0 1.00 SS
IMPERIAL 165.9 A 7.0 20.00 ss
PISGAH-BULLION MTN.-MESQUITE LK 166.5 B 7.1 0.60 SS
CALICO - HIDALGO 169.2 1 B 7.1 0. 60 ss
SANTA SUSANA 171.5 1 B 6.6 5.00 DS
HOLSER 180.4 1 B 6.5 0.40 DS
SIMI-SANTA ROSA 187.9 1 B 6.7 1.00 DS
OAK RIDGE (Onshore) 188.7 1 B 6.9 4.00 DS
SAN CAYETANO 197.2 1 B 6.8 6.00 DS
GRAVEL HILLS - HARPER LAKE 197.7 1 B 6.9 0.60 SS
BLACKWATER 212.8 1 B 6.9 0.60 t SS
VENTURA - PITAS POINT 216.1 1 B 6.8 1.00 DS
SANTA YNEZ (East) 216.9 1 B 7.0 2.00 SS
SANTA CRUZ ISLAND 224.7 1 B 6.8 1.00 DS
M.RIDGE-ARROYO PARIDA-SANTA ANA 226.7 1 B 6.7 0.40 1 DS
RED MOUNTAIN 230.1 1 B 6.8 2.00 1 DS
GARLOCK (West) 233.4 1 A 7.1 6.00 SS
PLEITO THRUST 238.6 1 B 6.8 2.00 DS
BIG PINE 244.4 1 B 6.7 0.80 1 SS
GARLOCK (East) 248.3 1 A 7.3 7.00 1 SS
WHITE WOLF 259.3 1 B 7.2 1 2.00 1 DS
SANTA ROSA ISLAND 259.6 1 B 1 6.9 1 1.00 1 DS
SANTA YNEZ (West) 262.0 1 B 1 6.9 2.00 1 SS
So. SIERRA NEVADA 272.7 1 B 1 7.1 1 0.10 1 DS
LITTLE LAKE 277.5 1 B 1 6.7 i 0.70 1 SS
OWL LAKE 278.8 1 B 1 6.5 1 2.00 1 SS
PANAMINT VALLEY | 279.0 1 B 1 7.2 1 2.50 1 SS
TANK CANYON j 279.6 1 B 1 6.5 1 1.00 1 DS
DEATH VALLEY (South) | 288.2 1 B 1 6.9 1 4. 00 1 SS
LOS ALAMOS-W. BASELINE | 304.2 1 B 1 6.8 1 0.70 1 DS
LIONS HEAD I 321.7 1 B 1 6.6 1 0.02 1 DS
DEATH VALLEY (Graben) | 329.1 1 B 1 6.9 1 4.00 1 DS
SAN LUIS RANGE (S. Margin) | 331.4 1 B 1 7.0 1 0.20 1 DS
SAN JUAN 1 332.1 1 B 1 7.0 1 1.00 1 SS
CASMALIA (Orcutt Frontal Fault) | 339.8 1 B 1 6.5 1 0.25 1 DS
OWENS VALLEY | 345.9 1 B 1 7.6 1 1.50 1 SS
LOS OSOS 1 361.5 1 B 1 6.8 1 0.50 1 DS
HOSGRI 1 367.5 1 B 1 7.3 1 2.50 1 SS
HUNTER MTN. - SALINE VALLEY | 372.5 1 B 1 7.0 1 2.50 1 SS
INDEPENDENCE | 381.7 1 B 1 6.9 1 0.20 1 DS
DEATH VALLEY (Northern) j 382.4 1 A 1 7.2 1 5.00 1 SS
RINCONADA j 382.4 1 B 1 7.3 1 1.00 1 SS
BIRCH CREEK | 438.0 1 B 1 6.5 1 0.70 1 DS
SAN ANDREAS (Creeping) | 438.7 1 B 1 5.0 1 34.00 1 SS
WHITE MOUNTAINS I 442.6 1 B 1 7.1 1 1.00 1 SS
DEEP SPRINGS I 461.1 1 B 1 6.6 1 0.80 1 DS
SUMMARY OF FAULT PARAMETERS
Page
1 APPROX. SOURCE MAX. SLIP 1 FAULT
ABBREVIATED 1 DISTANCE TYPE MAG. RATE 1 TYPE
FAULT NAME 1 (km) (A,B,C) (Mw) (mm/yr)
1(SS,DS,BT)
DEATH VALLEY (N. of Cucamongo) 1 466.4 A 7 .0 5.00 1 SS
ROUND VALLEY (E. of S.N.Mtns.) 1 473.0 B 6 .8 1.00 1 DS
FISH SLOUGH 1 480.9 B 6 . 6 0.20 1 DS
HILTON CREEK 1 499.1 B 6 .7 2.50 1 DS
ORTIGALITA 1 523.1 B 6 .9 1.00 1 SS
HARTLEY SPRINGS 1 523.3 1 B 6 .6 0.50 1 DS
CALAVERAS (So.of Calaveras Res) 1 528.6 B 6 .2 15.00 1 SS
MONTEREY BAY - TULARCITOS 1 531.3 1 B 7 1 0.50 1 DS
PALO COLORADO - SUR 1 532.2 1 B 7 0 3.00 1 SS
QUIEN SABE 1 541.9 1 B 6 5 1.00 1 SS
MONO LAKE 1 559.3 1 B 6 6 2.50 1 DS
ZAYANTE-VERGELES 1 560.4 1 B 6 8 0.10 1 SS
SAN ANDREAS (1906) 1 565.6 1 A 7 9 24.00 1 SS
SARGENT 1 565.7 1 B 6 8 3.00 1 SS
ROBINSON CREEK 1 590.6 1 B 6 5 0.50 1 DS
SAN GREGORIO 1 606.6 1 A 7 3 5.00 1 SS
GREENVILLE 1 615.5 1 B 6 9 2.00 1 SS
MONTE VISTA - SHANNON 1 615.8 1 B 6 5 0.40 1 DS
HAYWARD (SE Extension) 1 615.9 1 B 6 5 3.00 1 SS
ANTELOPE VALLEY 1 630.9 1 B 6 7 0.80 1 DS
HAYWARD (Total Length) 1 635.6 1 A 7 1 1 9.00 1 SS
CALAVERAS (No.of Calaveras Res) 1 635.6 1 B 1 6 8 1 6.00 1 SS
GENOA 1 656.2 1 B 1 6 9 1.00 1 DS
CONCORD - GREEN VALLEY 1 683.4 1 B 1 6 9 6.00 1 SS
RODGERS CREEK 1 722.2 1 A 1 7 0 1 9.00 1 SS
WEST NAPA 1 723.1 1 B 1 6 5 1 1.00 1 SS
POINT REYES 1 741.0 1 B 1 6 8 1 0.30 1 DS
HUNTING CREEK - BERRYESSA 1 745.5 1 B 1 6 9 1 6.00 1 SS
MAACAMA (South) 1 784.9 1 B 1 6 9 1 9.00 1 SS
COLLAYOMI 1 801.8 1 B 1 6 5 1 0.60 1 SS
BARTLETT SPRINGS 1 805.3 1 A 1 7 1 1 6.00 1 ss
MAACAMA (Central) 1 826.5 1 A 1 7 1 1 9.00 1 ss
MAACAMA (North) 1 886.1 1 A 1 7. 1 1 9.00 1 ss ROUND VALLEY (N. S.F.Bay) 1 892.3 1 B 1 6. 8 1 6.00 1 ss
BATTLE CREEK 1 915.9 1 B 1 6. 5 i 0.50 1 DS
LAKE MOUNTAIN 1 950.7 1 B 1 6. 7 1 6.00 1 ss
GARBERVILLE-BRICELAND 1 967.8 1 B 1 6. 9 1 9.00 1 ss
MENDOCINO FAULT ZONE 1 1024.1 1 A 1 7. 4 1 35.00 1 DS
LITTLE SALMON (Onshore) 1 1030.8 1 A 1 7. 0 1 5.00 1 DS
MAD RIVER 1 1033.6 1 B 1 7. 1 1 0.70 1 DS
CASCADIA SUBDUCTION ZONE 1 1037.7 1 A 1 8. 3 1 35.00 1 DS
McKINLEYVILLE 1 1044.0 1 B 1 7. 0 1 0.60 1 DS
TRINIDAD 1 1045.5 1 B 1 7. 3 1 2.50 1 DS
FICKLE HILL 1 1046.0 1 B 1 6. 9 1 0.60 1 DS
TABLE BLUFF 1 1051.3 1 B 1 7. 0 1 0.60 1 DS
LITTLE SALMON (Offshore) 1 1064.7 1 B 1 7. 1 1 1.00 1 DS
3
c o
o o
<
05
o
0
Q.
0)
DESIGN RESPONSE SPECTRUM
Seismic Zone: 0.4 Soil Profile: SC
2.5
2.0
1.5
1.0
0.5
0.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Period Seconds
3.5 4.0 4.5 5.0
GRADING GUIDELINES
GracJIng shoulcJ be performed to at least the minimum requirements of the governing
agencies, Chapter 33 of the Uniform Building Code, the geotechnical report and the
guidelines presented below. All of the guidelines may not apply to a specific site and
additional recommendations may be necessary during the grading phase.
Site Clearing
Trees, dense vegetation, and other deleterious materials should be removed from the
site. Non-organic debris or concrete may be placed in deeper fill areas under direction
of the Soils engineer.
Subdrainage
1. During grading, the Geologist and Soils Engineer should evaluate the necessity
of placing additional drains (see Plate A).
2. All subdrainage systems should be observed by the Geologist and Soils Engineer
during construction and prior to covering with compacted fill.
3. Consideration should be given to having subdrains located by the project
surveyors. Outlets should be located and protected.
Treatment of Existing Ground
1. All heavy vegetation, rubbish and other deleterious materials should be disposed
of off site.
2. All surficial deposits including alluvium and colluvium should be removed unless
otherwise indicated in the text of this report. Groundwater existing in the alluvial
areas may make excavation difficult. Deeper removals than indicated in the text
of the report may be necessary due to saturation during winter months.
3. Subsequent to removals, the natural ground should be processed to a depth of
six inches, moistened to near optimum moisture conditions and compacted to fill
standards.
Fill Placement
1. Most site soil and bedrock may be reused for compacted fill; however, some
special processing or handling may be required (see report). Highly organic or
contaminated soil should not be used for compacted fill.
(1)
2. Material used in the compacting process should be evenly spread, moisture
conditioned, processed, and compacted in thin lifts not to exceed six inches in
thickness to obtain a uniformly dense layer. The fill should be placed and
compacted on a horizontal plane, unless otherwise found acceptable by the Soils
Engineer.
3. If the moisture content or relative density varies from that acceptable to the Soils
engineer, the Contractor should rework the fill until it is in accordance with the
following:
a) Moisture content of the fill should be at or above optimum moisture.
Moisture should be evenly distributed without wet and dry pockets. Pre-
watering of cut or removal areas should be considered in addition to
watering during fill placement, particularly in clay or dry surficial soils.
b) Each six inch layer should be compacted to at least 90 percent of the
maximum density in compliance with the testing method specified by the
controlling governmental agency. In this case, the testing method is ASTM
Test Designation D-1557-91.
4. Side-hill fills should have a minimum equipment-width key at their toe excavated
through all surficial soil and into competent material (see report) and tilted back
into the hill (Plate A). As the fill is elevated, it should be benched through surficial
deposits and into competent bedrock or other material deemed suitable by the
Soils Engineer.
5. Rock fragments less than six inches in diameter may be utilized in the fill,
provided:
a) They are not placed in concentrated pockets;
b) There is a sufficient percentage of fine-grained material to surround the
rocks;
c) The distribution of the rocks is supervised by the Soils Engineer.
6. Rocks greater than six inches in diameter should be taken off site, or placed in
accordance with the recommendations of the Soils Engineer in areas designated
as suitable for rock disposal.
7. In clay soil large chunks or blocks are common; if in excess of six (6) inches
minimum dimension then they are considered as oversized. Sheepsfoot
compactors or other suitable methods should be used to break the up blocks.
(2)
8. The Contractor should be required to obtain a minimum relative compaction of 90
percent out to the finished slope face of fill slopes. This may be achieved by
either overbuilding the slope and cutting back to the compacted core, or by direct
compaction of the slope face with suitable equipment.
If fill slopes are built "at grade" using direct compaction methods then the slope
construction should be performed so that a constant gradient is maintained
throughout construction. Soil should not be "spilled" over the slope face nor
should slopes be "pushed out" to obtain grades. Compaction equipment should
compact each lift along the immediate top of slope. Slopes should be back
rolled approximately every 4 feet vertically as the slope is built. Density tests
should be taken periodically during grading on the flat surface of the fill three to
five feet horizontally from the face of the slope.
In addition, if a method other than over building and cutting back to the
compacted core is to be employed, slope compaction testing during construction
should include testing the outer six inches to three feet in the slope face to
determine if the required compaction is being achieved. Finish grade testing of
the slope should be performed after construction is complete. Each day the
Contractor should receive a copy ofthe Soils Engineer's "Daily Field Engineering
Report" which would indicate the results of field density tests that day.
9. Fill over cut slopes should be constructed in the following manner:
a) All surficial soils and weathered rock materials should be removed at the
cut-fill interface.
b) A key at least 1 equipment width wide (see report) and tipped at least 1
foot into slope should be excavated into competent materials and observed
by the Soils Engineer or his representative.
c) The cut portion of the slope should be constructed prior to fill placement
to evaluate if stabilization is necessary, the contractor should be
responsible for any additional earthwork created by placing fill priorto cut
excavation.
10. Transition lots (cut and fill) and lots above stabilization fills should be capped with
a four foot thick compacted fill blanket (or as indicated in the report).
11. Cut pads should be observed by the Geologist to evaluate the need for
overexcavation and replacement with fill. This may be necessary to reduce water
infiltration into highly fractured bedrock or other permeable zones,and/or due to
differing expansive potential of materials beneath a structure. The overexcavation
should be at least three feet. Deeper overexcavation may be recommended in
some cases.
(3)
12. Exploratory backhoe or dozer trenches still remaining after site removal should be
excavated and filled with compacted fill if they can be located.
Grading Observation and Testing
1. Obsen/ation of the fill placement should be provided by the Soils Engineer during
the progress of grading.
2. In general, density tests would be made at intervals not exceeding two feet of fill
height or every 1,000 cubic yards of fill placed. This criteria will vary depending
on soil conditions and the size of the fill. In any event, an adequate number of
field density tests should be made to evaluate if the required compaction and
moisture content is generally being obtained.
3. Density tests may be made on the surface material to receive fill, as required by
the Soils Engineer.
4. Cleanouts, processed ground to receive fill, key excavations,subdrains and rock
disposal should be observed by the Soils Engineer prior to placing any fill. It will
be the Contractor's responsibility to notify the Soils Engineer when such areas are
ready for observation.
5. A Geologist should observe subdrain construction.
6. A Geologist should observe benching prior to and during placement of fill.
Utilitv Trench Backfill
Utility trench backfill should be placed to the following standards:
1. Ninety percent of the laboratory standard if native material is used as backfill.
2. As an alternative, clean sand may be utilized and flooded into place. No specific
relative compaction would be required; however, observation, probing, and if
deemed necessary, testing may be required.
3. Exterior trenches, paralleling a footing and extending below a 1:1 plane projected
from the outside bottom edge of the footing, should be compacted to 90 percent
of the laboratory standard. Sand backfill, unless it is similar to the inplace fill,
should not be allowed in these trench backfill areas.
Density testing along with probing should be accomplished to verify the desired
results.
(4)