HomeMy WebLinkAboutCT 2016-0002; TOWN HOUSE; LIMITED GEOTECHINICAL INVESTIGATION PROPOSED RAILYARD LOFTS RESIDENTIAL DEVELOPMENT; 2013-03-21^ \
EAST COUNTY SOIL CONSULTATION
AND ENGINEERING, INC.
10925 HARTLEY ROAD, SUITE "I"
SANTEE, CALIFORNIA 92071
(619) 258-7901
Fax 258-7902
Mark Benjamin March 21,2013
Archipelago Development Project No 13-1106D5
P 0 Box 7050
Rancho Santa Fe, California 92067
Subject Limited Geotechnical Investigation
Proposed Railyard Lofts Residential Development
2685 State Street
Carlsbad, Cahforma 92008
Dear Mr Benjamm
In accordance with your request, we have performed a limited geotechmcal mvestigation at the
subject site to discuss the geotechmcal aspects of the project and provide recommendations for the
proposed development
Our investigation has found that the proposed building pad is pnmanly underlam by topsoil,
undocumented fill and alluvium to a depth of approximately 20 feet below existing grade These
soils were underlam by dense sandstone of the Santiago Formation to the explored depth of 25 feet
It is our opmion that the development of the proposed residential project is geotechmcally feasible
provided the recommendations herem are implemented m the design and construction
Should you have any questions with regard to the contents of this report, please do not hesitate to
contact our office
Respectfully submitted.
Mamadou Sahou Diallo, P E
RGB 54071, GE 2704
MSD\md
ARCHIPELAGO DEVELOPMENT/ KAILYARD LOFTS PROJECT NO 13-1I06D5
TABLE OF CONTENTS
INTRODUCTION 3
SCOPE OF SERVICES 3
SITE DESCRIPTION AND PROPOSED CONSTRUCTION .. 3
FIELD INVESTIGATION AND LABORATORY TESTING 4
GEOLOGY 4
Geologic Setting 4
Site Stratigraphy 4
SEISMICITY 5
Regional Seisrnicity 5
Seismic Analysis 5
2010 CBC Seismic Design Criteria 6
Geologic Hazard Assessment 6
GEOTECHNICAL EVALUATION 7
Compressible Soils 7
Expansive Soils 7
Groundwatei 7
CONCLUSIONS AND RECOMMENDATIONS 8
GRADING AND EARTHWORK 8
Clearing and Grubbing 8
Structural Improvement of Soils 8
Transitions Between Cut and Fill 9
Method and Cnteria of Compaction 9
Erosion Control 9
Standard Grading Guidelines 9
FOUNDATIONS AND SLABS 10
SETTLEMENT 10
PRESATURATION OF SLAB SUBGRADE 10
TEMPORARY SLOPES 1
TRENCH BACKFILL
DRAINAGE 1
FOUNDATION PLAN REVIEW 1
LIMITATIONS OF INVESTIGATION
ADDITIONAL SERVICES 12
PLATES
Plate 1 - Location of Exploratory Boreholes
Plate 2 - Summary Sheet (Exploration Borehole Logs)
Plate 3 - uses Soil Classification Chart
PAGE L-1, LABORATORY TEST RESULTS 16
REFERENCES 17
ARCHIPELAGO DEVELOPMENT/ RAIL YARD LOFTS PROJECT NO 13-1106D5
INTRODUCTION
This IS to present the findings and conclusions of a limited geotechnical investigation for the
proposed construction of a 3-story, residential building to be located at 2685 State Street, m the
City of Carlsbad, California
The objectives of the investigation were to evaluate the existing soils conditions and provide
recommendations for the proposed development
SCOPE OF SERVICES
The followmg services were provided during this mvestigation
O Site reconnaissance and review of published geologic, seismological and geotechnical reports
and maps pertment to the project area
O Subsurface exploration consistmg of five (5) boieholes within the limits of the proposed area
of development The boreholes were logged by our Staff Geologist
O Collection of representative soil samples at selected depths The obtained samples were sealed
in moisture-resistant containers and tiansported to the laboratory for subsequent analysis
O Laboiatory testing of samples representative of the types of soils encountered dunng the field
investigation
O Geologic and engineenng analysis of the field and laboratory data, which provided the basis
for our conclusions and recommendations
O Production of this report, which summanzes the results of the above analysis and presents our
fmdmgs and recommendations for the proposed development
SITE DESCRIPTION AND PROPOSED CONSTRUCTION
The subject site is a rectangular-shaped, multi-piupose lot located on the west side of State Street,
in the City of Carlsbad, California The vacant property encompasses an area of approximately
6,585 square feet It is presently used as a storage yard The site is relatively level with general
drainage to the west Vegetation consisted of grass Site boundanes include State Street to the
east, an alley to the west and eommercial developments to the lemaining directions
The preliminary site plan prepared by PASCO LARET SUITER and Associates of Solana Beach,
California indicates that the proposed construction will include a 4-umt residential complex It is
our understanding that the structure will be three-story, wood-framed and founded on contmuous
and spread footings with slab-on-grade floors Associated improvements \vill mclude a dnveway,
landscapmg and other appurtenances
ARCHIPELAGO DEVELOPMENT/ KAILYARD LOFTS PROJECT NO I3-I106D5
FIELD INVESTIGATION AND LABORATORY TESTING
From February 26 to March 19, 2013. five (5) boreholes were dulled to a maximum depth of
approximately 25 feet below existing grade with a hand auger and a dnil ng The approximate
locations of the boreholes are shown on the attached Plate No 1, entitled "Location of Exploratory
Boreholes" A contmuous log of the soils encountered was recorded at the time of excavation and
IS shown on Plate No 2 entitled "Summary Sheet" The soils were visually and texturally
classified according to the filed identification procedures set forth on Plate No 3 entitled "USCS
Soil Classification"
Following the field exploration, laboratory testing was performed to evaluate the pertinent
engineenng pioperties of the foundation matenals The laboratory-testing program included
moisture and density, particle size analysis, Atterbeig limits and expansion index tests These tests
were performed in general accordance with ASTM standards and other accepted methods Page L-1
and Plate No 2 provide a summary of the laboratory test results
GEOLOGY
Geologic Setting
The subject site is located withm the southern portion of what is known as the Peninsular Ranges
Geomorphic Province of California The geologic map pertaming to the area (reference No 6)
indicates that the site is underlain by terrace deposits (Qti) However, the following strata were
encountered
Site Stratigraphy
The subsurface descnptions provided are mterpreted from conditions exposed during the field
investigation and/or inferred fix)m the geologic literature Detailed descriptions of the subsurface
matenals encountered dunng the field investigation are presented on the exploration logs provided on
Plate No 2 The followmg paragraphs provide general descnptions of the encountered soil types
Topsoil
Topsoil is the surficial soil matenal that mantles the ground, usually containmg roots and other orgamc
matenals, which supports vegetation Topsoil observed in the boreholes was approximately 6 to 18
mches thick It consisted of dark brown, silty sand that was moist, loose and porous in consistency
with some orgamcs (roots and rootlets)
Undocumented Fill (Ouf)
Undocumented fill soils were encountered m most of the boreholes with a thickness of approximately
1 to 2 feet They generally consisted of reddish brown, silty sand that was moist and medium dense m
consistency In Boreholes 1 and 2, the fill was overlam by a layer of gravel, approximately 6-mch
thick
ARCHIPELAGO DEVELOP'vfENT/ RAILYARD LOFTS PROJECT NO 13-110605
Alluvixim (Qal)
The topsoil and undocumented fill were underlam by alluvium to a depth of approximately 20 feet
The top 4 feet of the alluvium consisted of a layer of sandy clay/ clayey sand that was very moist to
wet and medium stiff m consistency Dense sand was found below the clay layer Groundwater was
encountered at a depth of approximately 9 feet in the sand and some cavmg was observed
Santiago Formation (Tsa)
Bedrock matenals associated with the Santiago Formation were encountered below the alluvium
They generally consisted of light-colored sandstone that was very dense in consistency
SEISMICITY
Regional Seismicitv
Generally, Seismicity within California can be attributed to the regional tectomc movement taking
place along the San Andreas Fault Zone, which includes the San Andreas Fault and most parallel
and subparallel faults within the state The portion of southern California where the subject site is
located is considered seismically active Seismic hazards are attnbuted to groundshakmg from
earthquake events along nearby or more distant Quaternary faults The primary factors m
evaluating the effect an earthquake has on a site are the magnitude of the event, the distance from
the epicenter to the site and the near surface soil profile
Accordmg to the Fault-Rupture Hazard Zones Act of 1994 (revised Alquist-Pnolo Special Studies
Zones Act), quaternary faults have been classified as •active' faults, which show apparent surface
lupture dunng the last 11,000 years (i e , Holocene time) -Potentially-active" faults are those faults
with evidence of displacing Quaternary sediments between 11,000 to 16,000 years old
Seismic Analysis
Based on our evaluation, the closest known "active" fault is the Rose Canyon Fault located
approximately 7 5 kilometeis (4 7 miles) to the west The Rose Canyon Fault is the design fault of the
project due to the predicted credible fault magnitude and ground acceleration
The Seismicity of the site was evaluated utilizing determimstic methods (Eqseach/ Eqfault ver 3 0,
Blake, 2008) for active Quaternary faults within the regional vicimty The site may be subjected to
a Maximum Probable Earthquake of 6 9 Magnitude along the Rose Canyon fault, with a
corresponding Peak Ground Acceleration of 0 34g The maximum Probable Earthquake is defined
as the maximum earthquake that is considered likely to occur within a 100-year time period
The effective ground acceleration at the site is associated with the part of significant ground
mouon, which contains lepetitive strong-energy shaking, and which may produce structural
deformation As such, the effective or ' free field" ground acceleration is referred to as the
Repeatable High Ground Acceleration (RHGA) It has been determined by Ploessel and Slosson
(1974) that the RHGA is approximately equal to 65 percent of the Peak Ground Acceleration for
ARCHIPELAGO DEVELOPMENT/ RAIL YARD LOFTS PROJECT NO 13-1106D5
earthquakes occurring within 20 miles ot a site
RHGA at the site is 0 22g
201Q CBC Seismic Design Criteria
Based on the above, the calculated Credible
A review of the active fault maps pertaimng to the site mdicates the existence of the Rose Canyon
Fault Zone approximately 7 5 km to the west Ground shaking from this fault or one of the major
active faults m the region is the most likely happenmg to affect the site With respect to this
hazard, the site is comparable to others m the general area The proposed residential structure
should be designed m accordance with seismic design requirements of the 2010 Califonua Building
Code or the Structural Engineers Association of Cahforma usmg the following seismic design
parameters
PARAMETER VALUE 2010 CBC REFERENCE
Site Class D Table 1613 5 2
Mapped Spectral Acceleration For
Short Periods, S,
1 325 Figure 1613 5(3)
Mapped Spectral Acceleration For a
1-Second Period, S|
0 498 Figure 1613 5(4)
Site Coefficient, Fj 1 00 Table 1613 5 3(1)
Site Coefficient, Fy 1 502 Table 1613 5 3(2)
Geologic Hazard Assessment
Ground Rupture
Ground rupture due to active faulting is not considered likely due to the absence of known fault traces
withm the vicimty of the project, however, this possibility cannot be completely ruled out The
unlikely hazard of ground rupture should not preclude consideration of "flexible" design for on-site
ubhty Imes and connections
Liquefaction
Liquefaction involves the substantial loss of shear strength m saturated soils, usually sandy soils with a
loose consistency when subjected to earthquake shaking Based on the consistency of the underlying
alluvium and Santiago Formation, it is our opinion that the potential for hquefaction is low
Landsliding
There is no indication that landslides or unstable slope conditions exist on or adjacent to the project
site. There are no obvious geologic hazards related to landsliding to the proposed development or
adjacent properties
ARCHIPELAGO DEVELOPMENT/ RAILYARD LOFTS PROJECT NO 13-110605
Tsunamis and Seiches
The site is not subject to mundation by tsunamis due to its elevation The site is also not subject to
seiches (waves m confined bodies of water)
GEOTECHNICAL EVALUATION
Based on our mvestigation and evaluation of the collected mformation, we conclude that the proposed
construction is feasible fiom a geotechmcal standpoint provided the recommendations provided herein
will be properly implemented dunng structural development
Tlie major factors affecting the proposed development are the existence of undocumented fill and
highly expansive clayey soils at shallow depths A discussion of constraints and mibgative measures
are as follows
Compressible Soils
Our field observations and testmg indicate low compressibility within the dense alluvium and
sandstone of the Santiago Formation, which underlie the site However, loose topsoil and
undocumented fill were encountered to a depth of approximately 3 feet below existmg grades These
soils are compressible Also, the top 4 feet of the alluvium is highly expansive Due to the potential
for soil compression upon loadmg, remedial and select grading of these near surface soils, including
ovei excavation and recompaction will be required
Following implementation of the earthwork recommendations presented herein, the potential for soil
compression resulting from the new development has been estimated to be low The low-settlement
assessment assumes a well-planned and maintained site drainage system Recommendations
regarding mitigation by earthwork construction are presented m the Grading and Earthwork
recommendations section of this report
Expansive Soils
Expansion index tests were performed on select samples of the fill and alluvium (clay part) to
determine volumetnc change characteristics with change m moisture content Expansion indexes
of 4 and 123 were obtained respectively which indicates a low and very high expansion potential
for the subgrade soils
Groundwater
Perched groundwater was encountered at a depth of approximately 9 feet below existmg grade
However, we do not exjject groundwater to affect the proposed construction Recommendations to
prevent or mitigate the effects of poor surface dramage are presented m the Drainage section of this
report
ARCHIPELAGO DEVELOPMENT/ RAILYARD LOFTS PROJECT NO 13-110605
CONCLUSIONS AND RECOMMENDATIONS
The following conclusions and recommendations are based upon the analysis ol the data and
mfoimation obtained fiom our soil mvestigation This includes site reconnaissance, field
investigation, laboratory testmg and our general knowledge of the soils native to the site The site is
suitable for the proposed residential development provided the recommendations set forth are
implemented dunng construction
GRADING AND EARTHWORK
Based upon the proposed construction and the information obtamed dunng the field investigation, we
anticipate that the proposed stiuctuie will be founded on continuous and/ or spread footings, which are
supported by properly compacted fill The following gradmg and earthwork recommendations are
based upon the limited geotechnical investigation performed, and should be venfied dunng
construction by our field representative
Cleanng and Grubbing
All areas to be graded or to receive fill and/or structures should be cleared of vegetation Vegetation
and the debns from the cleanng operation should be properly disposed of off-site The area should be
thoroughly inspected for any possible buned objects, which need to be rerouted or removed pnor to
the inception of, or dunng gradmg All holes, trenches or pockets left by the removal of these objects
should be properly backfilled with compacted fill matenals as recommended in the Method and
Cntena of Compaction secton of this report
Structural Improvement of Soils
Information obtamed fkim our field and laboratory analysis indicates that loose topsoil and
undocumented fill cover the building pad to a depth of approximately 3 feet below existng grade In
addition, a 4-foot layer of highly expansive clay was underlying these soils These surficial soils are
susceptible to settlement upon loading Based upon the sod charactenstics, we recommend the
following.
* All topsoil, undocumented fill and clay layer should be completely removed fixDm areas, which
are planned to receive compacted fills and/or structural improvements The bottom of the
removal area should expose competent matenals as approved by ECSC&E geotechmcal
representative Pnor to the placement of new fill, the bottom of the removal area should be
scanfied a minimum depth of 6 inches, moisture-conditioned withm 2 percent above the
optunum moisture content, and then recompacted to at least 90 percent relative compaction
(ASTM D1557 test method) The anticipated depth of removal is approximately 6 feet
* Soils utilized as fill should be moisture-conditioned and recompacted m conformance with the
followmg Method and Cntena of Compaction section of this report The actual depth and
extent of any overexcavation and recompaction should be evaluated m the field by a
lepresentative of ECSC&E
ARCHIPELAGO DEVELOPMENT/ RAILYARD LOFTS PROJECT NO 13-1106D5
* An alternative to the overexcavation and recompaction of the building pad is to support the
proposed structure on caissons and grade beams Design parameters may be provided upon
request
Transitions Between Cut and Fill
The proposed structure is anticipated to be founded in properly compacted fill Cut to fill transitions
below the proposed structure should be eliminated during the earthwork construction as required m the
previous secton
Method and Criteria of Compaction
Compacted fills should consist of approved soil material, free of trash debns, roots, vegetation or other
deleteiious materials. Fill soils should be compacted by suitable compaction equipment m umform
loose lifts of 6 to 8 mches Unless otherwise specified, all soils subjected to recompaction should be
moisture-conditioned withm 2 percent over the optimum moisture content and compacted to at least
90 percent relative compaction per ASTM test method D1557
The on-site soils with the exception of the clay layer, after being processed to delete the
aforementioned deletenous materials, may be used for recompaction purposes The clay layer which
is highly expansive should not be used as fill It should be hauled off-site and replaced with granular,
non-expansive soils that should be evaluated and approved by ECSCE pnor to delivery to the site
Erosion Control
Due to the granular characteristics of the on-site soils, areas of recent gradmg or exposed ground may
be subject to erosion Dunng construction, surface water should be controlled via berms, gravel/
sandbags, silt fences, straw wattles, siltation basins, positive surface grades or other method to avoid
damage to the fmish work or adjoming properties All site entrances and exits must have coarse
gravel or steel shaker plates to minimize offsite sediment tracking Best Management Practices
(BMPs) must be used to protect storm drains and minimize pollution The contractor should take
measures to prevent erosion of graded areas until such time as permanent drainage and erosion control
measures have been installed After completion of gradmg, all excavated surfaces should exhibit
positive drainage and eliminate areas where water might pond
Standard Gradmg Guidehnes
Gradmg and earthwork should be conducted in accordance with the standard-of-practice methods for
this local, the guidelmes of the current edition of the Uniform Buildmg Code, and the requirements of
the junsd'ictional agency Where the information provided m the geotechmcal report differs fiem the
Standard Giadmg Gmdelmes, the requirements outlined m the report shall govern
ARCHIPELAGO DEVELOPMENT/ KAILYARD LOFTS PROJECT NO I3-1106D5
FOUNDATIONS AND SLABS
a Continuous and spread footings are suitable for use and should extend to a minimum depth of 24
inches below the lowest adjacent grade for the proposed three-story structure into the properly
compacted fill soils Continuous footings should be at least 18 inches in width and reinforced with
a mmimum of four #4 steel bars, two bars placed near the top of the footmgs and the other two bars
placed near the bottom of the footmgs Isolated or spread footings should have a mmimum width
of 24 inches Their reinforcement should consist of a minimum of #4 bars spaced 12 mches on
center (each way) and placed horizontally near the bottom The rmmmum reinforcement
recommended is based on soil charactenstics and is not mtended to supercede the structural
engmeei requirements
b. Intenor floor slabs should be a minimum 5-inch thick Reinforcement should consist of #3 bars
placed at 16 inches on center each way within the middle third of the slabs by supporting the steel
on chairs or concrete blocks "dobies" The slabs should be underlain by 2 inches of clean sand over
a 10-mil visqueen moisture barrier and a capillary break at least 2 inches thick, consisting of coarse
sand, gravel or crushed rock not exceeding 3/4 inch in size with no more than 5 percent passing the
#200 sieve The effect of concrete shnnkage will result m cracks m virtually all-concrete slabs To
leduce the extent of shnnkage, the concrete should be placed at a maximum of 4-inch slump The
minimum steel recommended is not mtended to prevent shnnkage cracks
c. An allowable soil beanng value of 2,000 pounds per square foot may be used for the design of
continuous and spread footings at least 12 inches wide and founded a mimmum of 12 inches into
properly compacted fill soils as set forth in the 2010 Califorma Building Code, Table 1806 2 This
value may be increased by 400 psf for each additional foot of depth or width to a maximum value
of 4,000 lb/ft2
d. Lateral resistance to honzontal movement may be provided by the soil passive pressure and the
fnction of concrete to soil An allowable passive pressure of 250 pounds per square foot per foot
of depth may be used A coefficient of fnction of 0 35 is recommended The soils passive pressure
as well as the beanng value may be increased by 1/3 for wind and seismic loadmg
SETTLEMENT
Settlement of compacted fill soils is normal and should be anticipated Because of the minor
thickness of the fill soils anticipated under the proposed footings, total and differential settlements
should be within acceptable limits
PRESATURATION OF SLAB SUBGRADE
Due the granular charactenstics and low expansion potential of the anticipated foundation soils,
presoakmg of subgrade pnor to concrete pour is not required However, subgrade soils m areas
receiving concrete should be watered pnor to concrete placement to mitigate any drymg shrinkage,
which may occur following site grading
10
ARCHIPELAGO DEVELOPMENT/ RAHYARD LOFTS PROJECT NO I3-I106D5
TEMPORARY SLOPES
For the excavation of foundations and utility trenches, and during remedial grading, temporary vertical
cuts to a maximum height of 4 feet may be constructed in fill or natuial soil Any temporary cuts
beyond the above height constramts should be shored or further laid back following a 1 1 (honzontal
to vertical) slope ratio OSHA guidelmes for trench excavation safety should be implemented during
construction
TRENCH BACKFILL
Excavations for utility fines, which extend under structural areas should be properly backfilled and
compacted Utilities should be bedded and backfilled with clean sand or approved granular soil to
a depth of at least one foot over the pipe This backfill should be uniformly watered and
compacted to a firm condition for pipe support The remainder of the backfill should be on-site
soils or non-expansive imported soils, which should be placed in thin lifts, moisture-conditioned
and compacted to at least 90% lelative compaction
DRAINAGE
Adequate measures should be undertaken to properly finish grade the site after the structure and
other improvements are in place, such that the drainage water within the site and adjacent
properties is diiected away from the foundations, footings, floor slabs and the tops of slopes via
ram gutters, downspouts, suiface swales and subsuiface drams towards the natural drainage for this
area A minimum gradient of 1 percent is recommended m hardscape areas For earth areas, a
minimum gradient of 5 percent away from the structure for a distance of at least 5 feet should be
provided Earth swales should have a mmunum gradient of 2 percent Dramage should be directed
to approved drainage facilities Proper surface and subsurface dramage will be required to
minimize the potential of water seekmg the level of the beanng soils under the foundations,
footings and floor slabs, which may otherwise result in undermining and differential settlement of
the structure and other improvements
FOUNDATION PLAN REVIEW
Our firm should review the foundation plans dunng the design phase to assure conformance with the
intent of this report During construction, foundation excavations should be observed by our
representaUve pnor to the placement of forms, reinforcement or concrete for conformance with the
plans and specifications
LIMITATIONS OF INVESTIGATION
Our mvestigation was performed usmg the skill and degree of care ordinarily exercised, under similar
circumstances, by reputable soils engmeers and geologists practicmg m this or similar localities No
other warranty, expressed or iirqilied, is made as to the conclusions and professional advice mcluded m
this report This report is prepared for the sole use of our client and may not be assigned to others
without the written consent of the client and ECSC&E, Inc.
11
ARCHIPELAGO DEVELOPMENT/ RAILYARD LOFTS PROJECT NO I3-II06D5
The samples collected and used for testmg and the observations made, are believed representative of
site conditions; however, soil and geologic conditions can vary sigmficantly between exploration
trenches, boreholes and surface exposures As in most major projects, conditions revealed by
construction excavations may vary with prelimmary findmgs If this occurs, the changed conditions
must be evaluated by a representative of ECSC&E and designs adjusted as required or alternate
designs recommended
This report is issued with the understandmg that it is the responsibility of the owner, or of his
representative to ensure that the information and recommendations contained herem are brought to the
attention of the project architect and engineer Appropnate recommendations should be incorporated
into the structural plans The necessary steps should be taken to see that the contractor and
subcontractors carry out such recommendations m the field
The findmgs of this report are vahd as of this present date However, changes m the conditions of a
property can occur with the passage of tune, whether they are due to natural processes or the works of
man on this or adjacent properties In addition, changes in applicable or appropnate standards may
occur from legislation or the broadenmg of knowledge Accordmgly, the findings of this report may
be invalidated wholly or partially by changes outside of our control Therefore, this report is subject to
review and should be updated after a penod of two years
ADDITIONAL SERVICES
The review of plans and specifications, field observations and testmg under our direction are integral
parts of the recommendations made m this report If East County Soil Consultation and Engmeermg,
Inc IS not retamed for these services, the client agrees to assume our responsibility for any potential
claims that may anse durmg construction Observation and testmg are additional services, which are
provided by our fum, and should be budgeted -withm the cost of development
Plates No 1 through 3, Page L-1 and References are parts of this report
12
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EAST COUNTY SOIL CONSULTATION
& ENGINEERING, INC
10925 HARTLEY RD SUITE I SANTEE, CA 92071
(619) 238 7901 fax (619) 258-7902
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ARCHIPELAGO DEVELOP MEHT/KAILYARD LOFTS PROJECT NO I3-II06D5
DEPTH
Surface
0 5'
1 5'
2 5
4 0'
5 5'
6 0'
100'
PLATE NO. 2
SUMMARY SHEET
BOREHOLE NO. 1
SOIL DESCRIPTION
GRAVEL
UNDOCUMENTED FH^L
reddish brown, dry to moist, medium dense, silty sand
ti rt n B »i
ALLUVIUM (Qal)
gray, moist to wet, medium stiff sandy clay
n M i» II t»
gray brown, moist, medium dense, clayey sand
light gray, moist, dense sand with silt
bottom of borehole, caving @ 8 5', giound water @9 0'
borehole backfilled 2/26/13
BOREHOLE NO. 2
Y
1 11 1
101 4
M
64
24 5
DEPTH SOIL DESCRIPTION
Surface GRAVEL
0 5'UNDOCUMENTED FILL
gray brown, moist, loose, silty sand
1 0'reddish brown, dry to moist, medium dense, silty sand
2 0'TOPSOIL
dark brown, moist, loose, porous, silty sand
25 alluvium (Qal)
gray, moist to wet, medium stiff sandy clay
6 0'light gray, moist, dense sand with silt
8 0'bottom of borehole, no caving, no groundwatei
borehole backfilled 3/12/13
Y M
Y = DR\ DENSITY IN PCF M = MOISTURE CONTENT IN %
13
A RCHIPELAGO DEVELOPMENT/ RAIL YARD LOFTS PROJECT NO 13-1106D5
PLATE NO. 2 (Continued)
SUMMARY SHEET
BOREHOLE NO. 3
DEPTH SOIL DESCRIPTION
Surface TOPSOIL
dark brown, moist, loose, porous, silty sand
1 0' UNDOCUMENTED FELL
reddish brown, dry to moist, medium dense, siity sand
2 0- alluvium (Qal)
g,ray, moist to wet, medium stiff sandy clay
6 0' light gray, moist, dense sand with silt
7 0 bottom of borehole, no caving, no groundwater
borehole backfilled 3/12/13
BOREHOLE NO. 4
DEPTH SOIL DESCRIPTION
Surface TOPSOIL
dark brown, moist, loose, porous, silty sand
2 5' ALLUVIUM (Qal)
gray, moist to wet, medium stiff sandy clay
6 0' light gray, moist, dense sand with silt
10 0' bottom of borehole, caving @ 8 5', groundwater @9 0'
borehole backfilled 3/12/13
M
Y M
Y = DR\ DENSITY IN PCF M = MOISTURE CONTENT IN %
14
DEPTH
Surface
0 5'
1 5'
2 0'
3 0'
6 0"
7 0'
10 0'
15 0'
20 0'
21 0'
24 0'
25 0
ARCHIPELAGO DEVELOPMENT/ KAILYARD LOFTS PROJECT NO I3-1I06D5
PLATE NO. 2 (Continued)
SUMMARY SHEET
BOREHOLE NO. 5
SOIL DESCRIPTION
TOPSOU.
dark brown, moist, loose, silty sand
UNDOCUMENTED FELL
reddish brown dry to moist, medium dense,
silty sand
II It n »» " "
ALLUVIUM
gray moist to wet soft to medium stiff sandy clay
11 IT II n tt rt
light gray, moist to wet medium dense
to dense sand with silt
SANTIAGO FORMATION (Tsa)
light colored, moist, dense, sandstone
bottom of boiehole, groundwater @9 0'
borehole backfilled with bentonite shavings 3/19/13
SPT
18
37
45
78
37
61
98 7
98 3
123 6
M
25 0
24 4
15 1
SPT = STANDARD PENETRATION TEST IN BLOWS/ FT
Y = DRY DENSITY IN PCF M ~ MOISTURE CONTENT IN %
15
MAJOR DIVISIONS SYMBOL DESCRIPTION
COARSE
GRAINED SOILS
(MORE THAN Vi OF SOIL
> NO 200 SIEVE SIZE)
GRAVELS
(MORE THAN 'A
OF COARSE
FRACTION
>N0 4 SIEVE
SIZE)
GW WELL GRADED GRAVELS OR GRAVEL- SAND
MIXTURES, LITTLE OR NO FINES
GP POORLY GRADED GRAVELS OR GRAVEL-SAND
MIXTURES, UTTLE OR NO FINES
GM SILTY GRAVELS, GRAVEL-SAND-SILT MDCTURES
GC CLAYEY GRAVELS, GRAVEL-SAND-CLAY MIXTURES
SANDS
(MORE THAN 'A
OF COARSE
FRACTION
< NO 4 SIEVE
SIZE)
SW WELL GRADED SANDS OR GRAVELLY SANDS,
LITTLE OR NO FINES
SP POORLY GRADED SANDS OR GRAVELLY SANDS,
LITTLE OR NO FINES
SM SILTY SANDS, SILT-SAND MDCTURES
sc CLAYEY SANDS, SAND-CLAY MIXTURES
FINE GRAINED
SOILS
(MORE THAN 'A OF SOIL
< NO 200 SIEVE SIZE)
SILTS &
CLAYS
UQUID LIMIT
<50
ML INORGANIC SILTS AND VERY FINE SANDS. ROCK
FLOUR, SE-TY OR CLAYEY FINE SANDS OR CLAYEY
SILTS WITH SLIGHT PLASTICITY
CL INORGANIC CLAYS OF LOW TO MEDIUM
PLASTICITY, GRAVELLY CLAYS, SANDY CLAYS,
SILTY CLAYS, LEAN CLAYS
OL ORGANIC SILTS AND ORGANIC SILTY CLAYS OF
LOW PLASTICITY
SILTS &
CLAYS
UQUID UMIT
>50
MH INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS
FINE SANDY OR SILTY SOILS, ELASTIC SILTS
CH INORGANIC CLAYS OF HIGH PLASTICITY, FAT
CLAYS
OH ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY,
ORGANIC SILTY CLAYS ORGANIC SILTS
fflGHLY ORGANIC SOILS Pt PEAT AND OTHER HIGHLY ORGANIC SOILS
CLASSIFICATION CHART (UNIFIED SOIL CLASSIFICATION SYSTEM)
CLASsmc^noN RANGE OF GRAIN SIZES
U S STANDARD GRAIN SIZE IN
SIEVE SIZE NULLIMETERS
BOLLDERS Above 12 Inches Above 305
COBBLES 12 Inches To 3 Inches 30J To 76 2
GRAVEL 3 Inches to No 4 76 2to4 76
Coarac 3 Inches to Vi Inch 76 2 to 19 1
Fme V4 Inch to No 4 19 I to 4 76
SAND No 4 to No 200 4 76 to 0 074
Coarse No 4 to No 10 4 76 to 2 00
Medium No 10 to No 40 2 00 to 0 420
Fme No 40 to No 200 0 420 to 0 074
SILT AND CLAY Below No 200 Below 0 074
t rf li /
[»>«*«• »f * • ••
mtm WU.-U1
f -arj
LIQUID LIHIT (U.)
GRAIN SIZE CHART PLASTICITY CHART
EAST COUNTY SOIL CONSULTATION
AND ENGINEERING, INC
10925 HARTLEY ROAD, SUITE "I"
SANTEE, CALIFORNU 92071
U.S.C.S. SOIL CLASSIFICATION
RaI,//ARD lofts project
PROJECT NO. L3-1106D5
PLATE NO. 3
liARCrt Jl ^013
ARCHIPELAGO DEVELOPMENT/ KAILYARD LOFTS PROJECT NO I3-II06D5
PAGE L-1
LABORATORY TEST RESULTS
EXPANSION INDEX TEST (ASTM D4829)
INITIAL
MOISTURE
CONTENTI%')
SATURATED
MOISTURE
CONTENTr%)
INITIAL DRY
DENSITY
(PCF)
11 1
142
23 3
29 3
106 7
96 8
EXPANSION
INDEX
33
151
LOCATION
BH-1 @2 0'
BH-1 @ 11 0'
PARTICLE SIZE ANALYSIS (ASTM D422)
US
Standard
Sieve Size
Percent Passing
BH-1 @ 1 5'
Fill
Percent Passing
BH-1 @3 0'
Alluvium
Percent Passmg
BH-1 @5 5'
Alluvium
Percent Passmg
BH-l @8 0'
Alluvium
Percent Passmg
BH-5 @ 24 0'
Santiago Form
2"
1"
1/2"
3/8"
#4
m
#16
#30
#50
#100
#200
100
99
98
92
63
37
27
100
94
82
69
63
100
99
94
70
40
32
100
99
97
86
38
11
6
100
97
82
59
35
24
19
uses SM CL SC SP-SM SM
16
ARCHIPELAGO DEVELOPMENT/ KAILYARD LOFTS PROJECT NO I3-II06D5
REFERENCES
1 "2010 California Building Code, California Code of Regulations, Title 24, Part 2, Volume 2 of 2",
Published by International Code Council
2 "Eqfault/ Eqsearch, Version 3 0", by Blake, T F , 2000, Updated 2008
3 "Geotechnical and Foundation Engineering Design and Construction", by Robert W Day, 1999
4 "1997 Uniform Building Code, Volume 2, Structural Engineering Design Provisions", Published by
International Conference of Building Officials
5 "Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada to
be used with the 1997 Uniform Building Code", Published by International Conference of Building
Officials '
6 "Geologic Maps of the Northwestern Part of San Diego County, California", Department of
Conservation, Division of Mines and Geology, by Siang S Tan and Michael P Kennedy, 1996
7 "Bearing Capacity of Soils, Technical Engineenng and Design Guides as Adapted from the US
Army Corps of Engineers, No 7", Published by ASCE Press, 1994
8 "Foundations and Earth Structures, Design Manual 7 2", by Department of Navy Naval Facilities
Engineenng Command, May 1982, Revalidated by Change I September 1986
9 "Ground Motions and Soil Liquefaction during Earthquakes", by H B Seed and I M Idriss, 1982
17