07120087 - Soils oFFilcE Con
SOIL AND FOUNDATION INVESTIGATION
FOR:
PROPOSED.SINGLE FAMILY RESIDENTIAL RECEIVH
1. 10484 BYRNE AVENUE DEC 1 @1007•
CUPERTINO,CALIFORNIA
SUBMITTAE T ---
#1
• PREPARED FOR:
MR.REZA RAFU
' 1729 MARICH WAY
MOUNTAINNIEW,CA 94040
MIKCWAVTED
DEC 1 { 2007
BY:
ADCO ENGINEERING
99 NORTH FIRST STREET SUITE 203
SAN JOSE,CA 95113
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• 11) C 0 , rill
ENVIRONMENTAL, CIVIL & GEOTECHNICAL CONSULTANT
File No. 07-1370-S1 _
July 6, 2007
Mr. Reza Rafii • '
1729 Marich Way
Mountain View, CA 94040i '
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Subject: Proposed Single FamilY Resident
10484 Byrne Avenue '
Cupertino, CA
SOIL AND FOUNDATIONINVESTIGATION
Gentlemen: '
We are pleased to transmit hereivith the result of our soil and foundation investigation
performed on the Proposed addition located at 10484 Byrne Avenue in Cupertino, California.
Our finding indicate that the subject property is suitable for the proposed residential,
provided the recommendations contained in this report are carefully followed. This report shows
our findings in the substuface inVestigation, laboratory analysis, and our conclusions and
recommendations based on these findings.
If you have any quesiions or require additional information, please feel free to contact our
office at your convenience.
Very truly yours, , . 'Y
ADCO ENGINEERING
JOE B. BIDABADL P.E.' -ri?IS? .
/ aist - N0. 32817
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Exp ":6-1:4
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OF CAO
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99 North First Street • Suite 203 • San Jose, Ca 95113 •TEL: (408)263-2500 • FAX: (408)2£48•888e
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File No. 07-1370-S1
TABLE•OF CONTENTS
Geotechnical Investigation , Page No.
Introduction 2
Location and Description-of the'Site 2
Field Investigation 2
Laboratory Investigation ' . 2
Liquefaction 3
Soil Suitability of Site 3
Recommendations •
Grading Specifications. - 4
Drainage and Erosion . 5
Foundation Design Criteria 5,6
Basement Retaining Wall 6
General Recommendations_ 7
Concrete Slabs-on-grade Construction. 7
General Construction Requirement • 8
Limitation and Uniformity of Conditions . 9
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Appendix"A"
Figure 1 —Location Map, 10
Figure 2—.Site Plan 11
Appendix"B"
Figure 3 —Soil Classification 12
Figure 4—Eiploratory Boring Log . 13
Figure 5-Plasticitylndex Chart- 14 •
Figure 6—Drain System Detail 15 .
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SOIL INVESTIGATION
INTRODUCTION
The purpose of the soil investigation.was to gather sufficient data to provide recommendations
for foundation Engineering.This report presents an explanation of how we conducted that
investigation,the results of the testing program,our conclusions based upon their results,and our
recommendations forearthwork and foundation design to best suit the proposed development to
the existing natural conditions.
LOCATION AND DESCRIPTION•OF THE SITE
The investigatedsite isdocated at 10484:Byrne Avenue in Cupertino,California At the time of
our investigation the ground surface:was Hat in the area of the proposed residential development
and sumunded by the residential area
Field Investigation
After consideration of the nature of the proposed development,review of available data on the
area,and discussion,withthe client,a field investigation was conducted at the project site.It
included a surface site renaissance to detect any unusual surface features,and the drilling of
one exploratory boring on June 27,2007 to determine subsurface soil characteristics.
The approximate boring locations we shown on Appendix A,Figure 1 .The soil encountered
was logged continuously in the field.Relatively undisturbed subsurface samples were obtained
by pushing or hamiterrog a split tube sampler into the natural ground at various depths.The
boring log,Figure 4-.is a graphic representations of the soil profile,showing the depths at which
the sample was obtained.
LABORATORY INVESTIGATIONS
Laboratory testing program was performed to determine the physical and Engineering properties
of the soil underlying thesite.Moisture content and dry density tests were performed on the soil
samples in order to de.their consistencies,and the moisture variation throughout the
explored soil profile.A ie-mold direct shear test was run to obtain strengbt parameters for use in
foundation design characteristic;The sample subjected to the direct shear test was allowed access
to water for at least 24 houis.prier to.testin and then sheared in an undrained state at loads of 1 ,
2,3 ,and 4 kips(.5;:9, 1 A'and-1.8.m is tons).Atterberg limits tests were also performed on the
near-surface soil to obtain the expansion potential of the soil.
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LIQUEFACTION
- Liquefaction is satwation of loose sands and silts with less than 15%clay content(cohesionless
material)from a solid state to a semi-liquid state.This occurs under vibratory condition such as
those induced by an earthquake.The soils tendency to compact is accompanied by an increase in
water pressure within the soil,which results in movement of water from the voids.The resulting
upward flow of water will often.turn sand into a liquified condition(loss of density).
We consider the ligoifaetion potential at the site to be low due to a gravelly and dense nature of
the soil.
SOIL SUITABILITYOF SITE
The site covered by this investigation is suitable for the proposed construction on either natural
ground or Engineered filll,provided the recommendations set forth in this report are incorporated
into the design considerations and the project plans and specifications.The design of the
structures and foundations shall meet local building code requirements for seismic effects.
The native soils are suitable as Engineered fill.All organic material including grass or weeds 2 to
4 inches shall be stripped'prior to any,grading operations and transported away from all areas that
are to receive structures or engineered 511.
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- Recommendations
GRADING SPECIFICATIONS:
1. The placement of fill and control of any grading operations at the site shall be done in
accordance widt,the recommendations of this report prepared by ADCO ENGINEERING.
These recommendations set forth the'minimum standards to satisfy all requirements of
this report.
2. All existing surface;and subsurface:structures that will not be incorporated in the final
development shall be removed prior to any grading operations.These objects shall be
accurately loCated on the grading plans(prepared by the project civil Engineer)to assist
the field Engineerin establishing proper control over their removal.This is to include but
not limited tn'atrees',basement;utility lines,underground tanks,and any other
inmrovements:.A representative of ADCO ENGINEERING shall be present during the
demolition operation.
3. The depressions left by the removal of the surface and subsurface structures shall be
cleaned of all debris and backfilled'with clean,native, on-site soil. This backfill shall be
compacted to not less than 90%relative compaction. This operation shall be conducted
under the suPervision of a soil yagineer from ADCO ENGINEERING.
- 4. Following the stripping opeiations,.the theniexposed surface shall be scarified to a depth
of 8-12 inches,moisture conditioned as necessary and compacted to 90%relative •
compaction.'At this point,:the area will be condition to receive compacted structural fill if
necessary to attain desired pad elevation.
5. All structural fill whether imported or native soil shall be placed in uniform horizontal
lifts of not more than 6;to 9 inches in uncompacted thickness and compacted to not less
than 90%relativecompactionusing theASTM D1557-78 procedure.Five feet around the
entire perimeter of the:building pad shall also be compacted to not less than 90%relative
compaction.Before compaction begins;the fill shall be brought to a water content that
will permit proper compaction by_dtber: 1)aerating the material if it is too wet,or 2)
spraying the material.with water if it is too dry.Each lift shall be thoroughly mixed before
compaction to assure a uniform distribution of water content. When fill material includes
rocks, nesting of rooks willnot be permitted, and all voids shall be carefully filled and
properly compacted:No rocks larger than 4 inches in diameter shall be used in the
construction of the-building pad.
6. The soil Engineershall,be,notified at least 24 hours prior to commencement of any
grading operations;so that he may coordinate the work in the field with the contractor. All
imported borrow must be;approved bythe soil Engineer before being brought to the site.
Import soil must have a plasticity index no greater than(12)and an"R"value greater than
(25)-
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DRAINAGE AND EROSION
Proper surface and/or.subsurface drainage system is recommended in the development of a
general drainage plan for:the site,positive surface gradients should be provided to direct surface
water nm off from the house in td suitable discharge facilities.
FOUNDATION DESIGN CRITERIA
1. The proposed'structlme,.arood frame residential development may be supported by either a
perimeter strip and isolated interior spread footings or by friction piers and grade beam type
of foundation.Reoonim ndations for these types of foundation are discussed in the following
Paragraphs- . .
2.
hs-
2. Spread footings may be used where.woilconditions are uniform over the entire building pad.
The footings should be founded a minimum of 22-inches below the lowest adjacent pad
grade.Paint footing Shall be reinforced with a minimum of four#4 rebars,two at the top
and two near the bottom of the footing.
3. The above foundations maybe designed for an allowable bearing pressure of 2,000 ps.f. for
dead plus live loads,and can beincreased ased by.one-third for total loads(short term seismic and
wind)..
4. All foundation trenches should be flooded with 4-inch of water to reduce their swell potential.
• This presoaking should be done at least2 days prior to placement of concrete.
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5.A friction pier type foundation must be embedded minimum of 12 feet below the exterior
grade on flat area The depth and spacing of friction piers will depend upon the structure
loads transmitted to the piers:The allowable friction value for this type of foundation is 500
p.s.£.All perimeter piers'should be reinforced with a minimum of two#4 bars for its full
length with the reinforcem®t of the pier tied to the top reinforcement of the grade beam. -
First three feet of soil may be.ignored for calculation. If drilled caissons are to be ntilizM
they must be Used rat all interior and exterior eolomn. The soil Engineer has to inspect all
the drilled caisson holes prior to concrete pouring.
6.The grade beam shpuld be founded a Minimum depth of 12 inches below adjacent pad grade
and should be reinforced.witht mminiimm of four#4 bars,two near the top and two hear the
bottom.The grade beamsliould'be kept to the minimum width in order to minimize the effect
of uplift pressures created tithe'expansion of the soil beneath the beams.
7. We highly recommendthat a soil-Engineer be present during the drilling of the piers to make
any necessary_field adjustments.
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8. The above bearing values are for dead plus live loads, and may be increased by one-third for
short term seismic and wind loads.
9.The final design of the foundation and reinforcing required shall be determined by the
Engineer responsible for the foundation design.It is suggested that the foundation design be
reviewed by the soil Engineer prior to construction.
10.We do not anticipate•any'appreciable settlements, however slight settlement should be
considered in the design of the foundations and the proposed structures.
Basement Retaining Wall.
1. All facilities that will main a soil mass shall be designed for a lateral earth pressure(active)
equivalent to 50 pounds'emiivalent fluid pressure,plus surcharge loads.If the retaining walls are
restrained from free movement at both ends,they shall be designed for the earth pressure
resulting from 60•pounds equivalent"thud•pressure,to which shall be added surcharge loads.The
retaining wall footing should be sem"at a minimum depth of 24 inches where concrete walls are to
be higher than 5 feet,with a level front ground surface or at a minimum of 20 inches with the
natural ground surface on the front side.
2.In designing for alloaiable resistive lateral earth pressure(passive), 300 pounds equivalent fluid
pressure may be used with',tbe'resuit acting at the third point The top 2 feet of native soil shall be
neglected for the computation of passive resistance.
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3. A coefficient of friction of.35 shall be used for retaining wall design.
4.The above values assume a drained condition,and a moisture content compatible with those
encountered during our investigation.To promote proper drainage,a layer of at least 1 foot of
gravel or drain rock shall be plaSed•between the facility and the retained material. Either weep
holes or perforated pipes(perforations down)shall.be included in the design to conduct excess
water from behind the retaining"structure. Suitable outfall locations for drainage facilities shall be
chosen to minimize inhere erosion. The recommended allowable bearing capacity in native firm
material or fill is 2,000 pert Approximate safety factors against overturning and sliding should be
incorporated into,the dead"calculation.The basement walls shall be properly waterproof to
minimise moisture infiltration through the walls.
5. We recommend a through review.by ADCO ENGINEERING of all design pertaining to
facilities retaining-a•soilmass:
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General Recommendations
In order to relief the hydrostatic pressure and to prevent moisture intrusion through the basement
floor and walls,we recommend the following drainage system to be incorporated into the design
and construction of the subject project
A 4-inch diameter plastic perforated pipe system should be installed(perforation down)around
the perimeter of the basement walls.This drain line should be tied to a 4 or 6 inch diameter solid
drain pipes to cagy excess water to the nearest manhole sump pit.The basement walls shall be
properly waterproof to minimize moisture infiltration through the walls(Figure 6).
For the basement floor,the slab should be underlain by a minimum of 6-inches of clean crushed
rock Then a 4-inch diameter perforated drain pipe system shall be installed around the perimeter
and middle of the slab to carry out excess hydrostatic moisture throughout basement floor.The
pipe should be embedded by additional 6-inches of crushed rock Then the designated area shall
receive 4-inches of class 11 baserock/crushed rock,then place the miradri or equivalent moisture
barrier. If crushed rock is used,it shall be rolled in order to become interlocked and also to
minimize the sharp edges which might damage the moisture barrier material.
The moisture barrier shall be covered by 2-inches of sand prior to placement of reinforcing bars
and forming/pouring of the slab. Special care and attention should be given to protect the
moisture barrier material from being damaged.
All of the perforated drain pipes (perforation down) shall have a minimum of 2% slope toward
the manhole sump pit.
Concrete slabs-on-grade construction
1. A minimum of 6 inches(10 cm.) thick of class II baserock, and 2 inches(5.0 cm.) of sand
should be used between the finished subgrade and concrete slab.
2.Use of a vapor barrier under the concrete slab is optional depending on the nature of the floor
covering to be applied.If a plastic membrane is used,it should be placed between the
baserock and the sandy layer.
3.Prior to placing the vapor membrane or pouring concrete,the slab subgrade should be
moistened with water to reduce the swell potential if deemed necessary by the soil Engineer
at the time of construction.
LIMITATIONS AND UNIFORMITY OF CONDITIONS
1.The recommendations presented herin are based on the soil conditions revealed by our test
borings and evaluated for the proposed construction planned at the present time. If any unusual
soil conditions are encountered during the construction,or if the proposed construction will differ
from that planned at the present;time,ADCO ENGINEERING should be notified for
supplemental recommendations.
2. This report is issuedwith the understanding that it is the responsibility of the owner, or his
representative,to enure that the necessary steps are taken to see that the contractor carries out
the recommendations of this report-in.the'field.
3.The findings of this report are-valid as of the present time. However,the passing of time will
change the conditions of the existing property due to natural processes,works of man,from
legislation or the broadening of knowledge.Therefore,this report is subject to review and should
not be relied upon after a Period of one year.
4. This report was ptepared;upon request for our services,in accordance with currently accepted
standards of professionalsoil engineering practice.No warrenty based on the contents of this
report is intended;and none shall be inferred from the statements or opinions expressed herein.
We did not perform neither a geological nor.environmental study on this property.
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Appendix "A"
Figure 1 Location Map
Figure 2 - Site Plan
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File No. 07-1370-81 F SITE PLAN
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Appendix"B"
, Figure 3 —Soil Classification
Figure 4—.Exploratory Boring Log
. Figure 5—Plasticity Index
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:SOIL CLASSIFICATION
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• MAJOR DIVISIONS:: SYMBOL - : TYPICAL NABS -
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GRAVELS-
._._______.____
RAVSLr 610 Act e.$l atoned 9ts.els or 9tsv.l-sand milord.. little or w tis..
• More than ]/2]/2 of' •1`� lr mon~ �to R onv l-seed m1sns. tato. R r tis.
$ g mum ttaction ! - GM : C • ally 9mo.ls. grist-sandatata{eo
no. 4 slave side) .
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- GC rotE Claret gravels. 9tsvel-aand-elar abonroe
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wSANDS SB C.: Bell 9sadod eaadm a 9ts.sllr e4uds. llttis Moo Urea
° ® - SP +�•.• Poorly waled moods or - —
C •ti.. 0ta..ur Bands. little R no lien.
. mama
.a coarsetraetloa < SM t Silty sande
• sead�llt alytptss
... no. 4 sieve else)
o X •
o - sc. >R mayor Duda. sand-clay wan.
-ti
o - .HL I sdopahta slits aid o.q tics condi. tank Klee, all
1 ` SILTS & CLAYS lien a al.yer • t. else ellehc waaaiela a or el.y.:
51 n
CL isssatals diets k las a teams W..tla14. aravally cloys.
e LL < 50 :! sandy wys. silty flays, loan clay.
Mj y OL �1�)II) Otaanto anti and sant silty clays or I,. ow Plast.tity
`Sqjo
1
O N 9 eji iasrtaalc silts. Macaws or dlataast.ose tins sandy or silty
` SILTS i CLAYS seals.. elastic silts
~i. aossanssmainal
LL D.- 50 CH J' lsesyanio clay. R high pleaq
tscl , tat cloys
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OM !r... orsanls slays madam m4dlse Kies Plasctsi
• ,i ter- o79wlc patotr• organic slat tiny.
HIGHLY ORGANIC SOIL . Pt �` Peet tad other hlcslr ataanlc molls .
CLASSIFICATION CHART
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(Unified Soil Classification System)
CLASSIFI- OP GRAIN SIZES
CATION U.S. Standard Grain Sise 5, 11111111i 1111111111.
Siwe else in Millinotore ..MIl. ,
BOULDERS above • W
12 above 205 n {�
COBBLES 12•' to 2• 305 to 76.2 a 3 W ii.a mi
ti z ■�■ ��
GRAVELS 7° to No. 4 :76.2 to 4.76
. � ,
Coarse 2° to 2/{• 76.2 to 19.1 hg
Fine 2/40 to 3No./4 4 19.1 to 4.76
a ' iii Ian
SAND ■M OL .
Coarse . °wO. 0 ti••l os w..wlo00 o 4.76 to 0.074 0 10 20 30 40 50 60 70 80 90 1
4.76 to 3.00 •
Medium w. is to 00. 40 - 3.00 to 0.430 Li0OID LAY
Fine °o. 40 LO as. 100 0.410 tO 0.074
SILT i CLAY Helve Bo. 200 Below 0.074
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PLASTICITY CHART
FIg• 3 GRAIN SIZE CHART N1COBngr.
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Hole No.
Logged BY J.B. ' Exploratory Boring Log B-1
d Direct m
ae ••-• ,Eos Shear E Job No. 07-1370—S1
Test
4U 7C 3 '- a O
rn �
to om. 2.� "' b o a C
0o cm � � ai rn E a
a m _4 o a o m° DESCRIPTION
• Brown silty clay with some gravel)
moist, stiff
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115 15 32 1.221 1-1 5 •
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116 16 41 1-2 10
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15
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Boring terminated 0 15'
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20 •
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25
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Remarks:
Figure 4 — Logs of 'Test .Borings !J E
ADCO NGR.
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Ruin Mn n7 117n Cl
• PLASTICITY CHART
60
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0 20
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10
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0 10 20 30 40 50 . 60 70 80 90 100
Liquid Limit
PLASTICITY DATA
Plasti- Unified
Y Hole
Depth Liquid city Soil Clem-
Symbol No. Ft. Limit % Index % sificatioa
Symbol*
0 0-1 38 18 CI
* Soil type classification based on British suggested revisions to Unified
Soils Classification System
morn 5 _ 01 ..ai.ar.. 1..J.... - .