HomeMy WebLinkAboutW.O. 2407-A-SC; Carlsbad Airport Center Lot 1 & 10-Buie Comm.; Carlsbad Airport Center Lot 1 & 10; 1998-03-20PRELIMINARY GEOTECHNICAL EVALUATION
LOTS 1 AND 10, CARLSBAD AIRPORT CENTER
CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA
FOR
BUIE COMMUNITIES
380 STEVENS AVENUE, SUITE 305
SOLANA BEACH, CALIFORNIA 92075
W.0.2407-A-SC MARCH 20,1998
Geotechnical * Geologic • Environmental
5741 Palmer Way • Carlsbad, California 92008 • (760)438-3155 • FAX (760) 931-0915
March 20,1998
W.0.2407-A-SC
Buie Communities, Inc.
380 Stevens Avenue, Suite 305
Solana Beach, California 92075
Attention: Mr. Edwin L Barlow
Subject: Preliminary Geotechnical Evaluation, Lcte 1 and 10. Carlsbad Airport
Center, Carlsbad, San Diego County, California.
Dear Sin
In accordance with your aufihorization arid request, GeoSofls, Inc. (GSI) has performed a
preliminary geotechnicai evaluation of the subject property. The purpose of the study
was to evaluate the onsite soils and geologic conditions and their effects on the proposed
site development from a geotechnicai viewpoint.
EXECUTIVE SUMMARY
Based on our review of the available data (Appendix A), field exploration, laboratory
testing, and geologic and engineering analysis, the proposed development appears to be
feasible from a geotechnicai viewpoint, provided the recommendations presented in the
text of this report are properly incorporated into the design and construction of the project.
The most significant elements of this study are summarized below:
• Existitng fill materials within 1 foot of existing pad grade are generally
weatihered/ercded, are loose/soft, and/or do not meet the current mdustry minimum
standard of 90 percent (or greater) relative compaction. Recommendations for removal
and rBcompaciion are presented herein.
• Fcrmational (bedrock) materials will be encountered during site earthwork. Existing
bedrock materials withan 1 foot of existing pad grade are weathered and generally
Icose/soft and or do net meet the current industry minimum standard of 90 percent (or
greater) relative compaction. Recommendations for removal and recompaction are
presented herein.
The existing fill on Lot 1 is anticipated to vary in thickness from approximately 0 to 24
feet within the proposed "footprint" perimeter of the building. Because of the potential
for differential settlement of tine proposed structure, recommendations for
overexcavation are presented herein to mitigate this condition.
FormationaJ materials occur at existing grade throughout the lot. If a transition cut/fill
condition is created during gracing, recommendations are presented herein for
overexcavation.
Our laboratory test results indicate that soils with a medium expansion potential
underlie the srte. This should be considered during project design. Foundation design
and construction recommendations are provided herein for a medium expansion
potential classification.
Our laboratory test results indicate that the site materials have a high sulfate exposure,
potential for corrosion to concrete, have an acidic pH, and have a severe potential for
corrosion to exposed steel.
Subsurface and surface water are not anticipated to affect site development, provided
that the recommendations contained in this report are incorporated into the final design
and construction and that the prudent surface and subsurface drainage practices are
incorporated into the construction plans. Should perched groundwater conditions
develop, this office could assess the affected area(s) and provide the appropriate
recommendations to mitigate the observed groundwater conditions.
The seismicfty acceleration values provided herein should be considered during the
design of the proposed development.
Buie Communities. Inc. W.O. 2407-A-SC
Lots \ and 10, Carlsoad Airpcn Center March 20,19S8
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The opportunity to be of service is greatly appreciated. If you have any questions
concerning this report or if we may be of further assistance, please do not hesitate to
contact any of the undersigned.
Respectfully submitted,
GeoSoils, Inc.
Sherry L. Eaton
Project Manager
John P. Franklin
Engineering Geologist, C
SLE/JPF/WAC/mo
Distribution: (4) Addressee
Iliam A. Ciridon
otechnical Engineer, GE
Buie Communities, Inc.
Lots 1 and 10, Carlsbad Airport Center
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TABLE OF CONTENTS
SCOPE OF SERVICES 1
SITE DESCRIPTION 1
PROPOSED DEVELOPMENT _ . 3
FIELD STUDIES 3
GEOLOGY AND GEOLOGIC HAZARDS 3
EARTH MATERIALS 3
Artificial Fill - Undocumented (map symbol - Afu) 3
Delmar Formation (map symbol - Td) 4
FAULTING AND REGIONAL SEISMICITY 4
FauGdng 4
Seisrnictty 4
Seismic Shaking Parameters 6
GROUNDWATER 6
LIQUEFACTION 7
LABORATORY TESTING 7
Classification 7
Maximum Density Test 7
Expansion Potential 8
Direct Shear Testing 8
R-Vaiue Testing 8
Soluble Sulfates/'pH Resistivity 9
DISCUSSION AND CONCLUSIONS 9
General 9
Eartfri Materials 10
Existing Fill 10
Bedrock 10
Potential Settlement of Fill 10
Expansion Potential 11
Corrosion Potential 11
Subsurface and Surface Water 11
Regional Seismic Activity 11
GeoSoils, Inc.
EARTHWORK CONSTRUCTION RECOMMENDATIONS 11
General 11
Site Preparation 12
Removals (Unsuitable SurficiaJ Materials) ' 12
Overexcavation 12
Lot 1 12
Lot 10 13
Fill Placement 13
Erosion Control 14
FOUNDATION RECOMMENDATIONS 14
Preliminary Foundation Design 14
Bearing Value 14
Lateral Pressure 15
Construction 15
Medium Expansion Potential (Expansion Index 51 to 90) 15
High Expansion Potential (Expansion Index 91 to 120) 16
CORROSION AND CONCRETE MIX 17
RETAINING WALL RECOMMENDATIONS 18
General 18
Restrained Walls 18
Loading Dock Wall 18
Other Walls 19
Cantilevered Walls 19
Wail Backfill and Drainage 20
Retaining Wall Footing Transitions 20
PRELIMINARY PAVEMENT DESIGN 24
FLATWORK AND ASSOCIATED IMPROVEMENTS 26
Tile Flooring 27
Gutters and Downspouts 27
Exterior Slabs and Walkways 27
ADDITIONAL RECOMMENDATIONS/DEVELOPMENT CRITERIA 28
Additional Site Improvements 28
Erosion and Sedimentation Control 28
Landscape Maintenance and Planting 28
Drainage 29
Footing Trench Excavation 30
Trench Backfill 30
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PLAN REVIEW 30
LIMITATIONS 31
FIGURES:
Figure 1 - Site Location Map 2
Figure 2 - Caifomia Fault Map 5
Figure 3 - Schematic of Site Wall Drain (Option A) 21
Figure 4 - Schematic of Site Wall Drain (Option B) 22
Figure 5 - Schematic of Site Wai! Drain (Option C) 23
ATTACHMENTS:
Appendix A - References Rear of Text
Appendix B - Boring Logs Rear of Text
Appendix C - Laboratory Test Results Rear of Text
Appendix D - Grading Guidelines Rear of Text
Appendix E - Pavement Grading Guidelines Rear of Text
Rate - Geotechrriical Map Rear of Text in Pocket
3uie Communities Table of Contents
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PRELIMINARY GZOTECHNICAL EVALUATION
LOTS 1 AND 10
CARLSBAD AIRPORT CENTER
CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA
SCOPE OF SERVICES
The scope of our services has included the following:
1. Review of available soils and; geologic data for the site area, including aerial
photographs (Appendix A).
2. Subsurface exploration consisting of eight hand-auger borings, for geotechnical
logging and sampling.
3. Pertinent laboratory testing of representative soil samples collected dunmg our
subsurface exploration progrann.
4. General areal seismicity and liquefaction evaluation.
5. Appropriate engineering and geologic anafiysis of data collected and preparation
of this report.
SITE DESCRIPTION
The subject property consists of two previously-graded lots within Unit 1 of the C&rlsbad
Airport Center business park. Lot 1 is bounded cm the north by Owens Avenue,, on the
east by Camino Vida Robfe, on the souflh by Palomar Airport Road, and on the wesfi by Lot
10. Lot 10 is bounded on the north by Lots 2 and 3, on the west by Lot 9, on the south by
Palomar Airport Road, an»d on the east by Lot 1.
The building pads on the Sots are generally flat lying, and vegetation consists of a sparse
to moderate growth of weeds. Cut and fill slopes, up to about 4O feet high, descend at an
inclination of 2:1 (horizontal to vertical) from Lots 1 and 10 to Palomar Airport Road and
Camino Vida Roble. A cut slope, up to about 40 feet high, ascends from Lot 10 to Lots 2
and 3 at an inclination of 2:1 (horizontal to vertical).
The lots are within Phase 1 of the Carlsbad Airport Center, wnich was graded iin 1985
through 1986 under the observation and testing services of Moore & Taber. Our review
of the as graded report (Moore & Tabeir, 1987) indicates thai Lot 1 is underlain by a cut/fill
transition condition, and fills up to about 24 feet thick underlie She easterly portion of Lot
1. Lot 10 is a cut lot, underlain by ^ie Tertiary Delmar Formanon, consisting of sandstones
and shales (Moore & Taber, 1987). Cut slopes, constructed during tract grading, have
been mapped by Moore & Taber (19S7), who has indicated they are grossly stable.
GeoSoils, Inc.
Base Map: Enctnitas Quadrangle, California—San Diego Co., 7.5 Minute Series (Topographic),
1968 (photo, revised 1975), by USGS; San Luis Rey Quadrangle, California—San Diego Co., 7.5
Minute Series (Topographic), 1968 (photo revised 1975), by USGS, 1"=2000'
Base Map: The Thomas Guide, San Diego County Street Guide and Directory, 1998 Edition, by
Thomas Bros. Maps, page 1127, 1"=1/2 mile
R«produc*d with p«nms*ion granted by Thomas Bros. Uaps.Thi* map w copyrtgftted by Tnonua Bros. Maps, it is unlawful
to copy or reproduce «• or any part th*r*of, whathtf forpersonal use or resale, without permission. All rights reserved.
N
W.O.
2407-A-SC
SITE LOCATION MAP
Figure 1
PROPOSED DEVELOPMENT
It is our understanding that the proposed development would consist of finish grading to
create pads for a proposed office building on each lot and associated driveway, parking,
utility, and landscape improvements on each lot. It is also our understanding that the
buildings will be three-story structures, utilizing wood-frame or masonry-block construction
with slab-on-grade floors. Building loads are assumed to be typical for this type of
relatively light construction.
FIELD STUDIES
Field studies conducted during our evaluation of the property for this study consisted of
geologic reconnaissance, geologic mapping, and excavation of eight hand-auger borings
for evaluation of near-surface soil and geologic materials. The borings were logged by a
geologist from our firm, who collected representative samples from the excavations for
appropriate laboratory testing. The logs of the borings are presented in Appendix B, and
the locations of the borings are presented on Plate 1.
ID GEOLOGIC
The subject property has been evaluated previously (Moore & Taber, 1987), and the
previously described geologic and seismic conditions generally have not changed.
Additional comments regarding site seismicity aid secondary hazards are provided herean,
as warranted.
EARTH MATERIALS
Earth materials underlying the site consist of artificial fill and the Delmar Formation. These
earth materials are described, from youngest to oldest:
Artificial Fill - Undocumented (map symbol Aftri
Artificial fill materials placed during tract grading (Moore & Taber, 1987) in the southeastern
corner of Lot 1 were encountered during our field study in boring B-7. These materials
consisted of brownish gray, sandy silts. The materials were weathered/eroded, wet, and
soft in the upper 1 foot, graded to moist and medium stiff at 1 foot in depth, and graded to
stiff at 2 feet in depth. These materials are reported to be up to 24 feet thick on this lot
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Delmar Formation (map symbol -Td)
Sedimentary bedrock deposits of the Deimar Formation were encountered during our field
study at the surface and in our borings B-1, B-2, B-3, B-4, B-5, B-6, and B-8. These
materials generally were olive gray silty sandstones snd sandy siltstones. The materials
were wet and loose/soft in the upper foot and graded to moist and dense/stiff at 1 foot in
depth.
FAULTING AND REGIONAL SEISMICITY
Faulting
Faulting for the site was previously evaluated (Moore & Taber, 1987), and conditions
generally have not changed. However, the relationship of the site location to the major
mapped faults is indicated on the California Fault Map (Rgure 2).
Seism icity
The acceleration-attenuation relations of Joyner and Boore (1982) and Campbell and
Bozorgnia (1994) have been incorporated into EQFAULT (Blake, 1997). For this study,
peak horizontal ground accelerations anticipated at the srte were determined based on the
random mean and mean plus 1 sigma attenuation curves developed by Joyner and Boore
(1982) and Campbell and Bozorgnia (1994). These acceleration-attenuation relations have
been incorporated in EQFAULT, a computer program by TTiomas F. Blake (1997), which
performs deterministic seismic hazard analyses using up to 150 digitized California faults
as earthquake sources. The program estimates the closest distance between eacJi fault
and a user-specified file. If a fault is found to be within a user-selected radius, the program
estimates peak horizontal ground acceleration that may occur at the site from the upper
bound (maximum credible) and "maximum probable' earthquakes on that fault.
Site acceleration as a percentage of the acceleration of gravity (g) is computed by any of
the 14 user-selected acceleration-attenuation relations tftat are contained in EQFAULT.
Based on the above, peak horizontal ground accelerations from a upper- bound (maximum
credible) event may be on the Ofder of 0.45 g to 0.60 g, and a maximum probable event
may be on the order of 0.30 g to 0.37 g.
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SAN FRANCISCO
SITE LOCATION (-):
Lctitude - 33.1203
L-nc"tude —
Lns" 1 one '0 CAC
W.O. 2407-A-SC Figure 2
GeoSoils, Inc.
Seismic Shakirta Parameters
Based on the site conditions, Chapter 16 of the Unnform Building Code (international
Conference of Building Officials, 1997) and Peterson and others (1996), the following
seismic parameters are provkJed.
Seismic zone (per Figure 16-2*)
Soil Profife Type (per Table 16-J*)
Joyner and Boore Subgrade Type
Seismic Source Type (perTsble 16-U*)
Distance to Seismic Source
Upper Bound Earthquake
4
SE
Class D
B
2 mi. (3 km)
M^&fl
* Figure and table references from Chapter 1 6 of the Uniform Building Code (1 997).
GROUNDWATER
Subsurface water was not encountered wfthin the property during field work performed in
preparation of tihis report. Water wells were not observed onsfte or in the immediate
vicinity of the property during our site reconnaissance. Historic well(s) were not reported
to be located wf&iin the study area (State of California, 1967). Groundwater depths were
also not reported in the area, and groundwater was not encountered during our
geotechnical evaluation of the adjacent Phase 2 of the business park (GSI, 1991). ft is our
understanding that groundwater does exist which tine Canyon de las Encinas canyon
bottom, about 4O feet below site grade.
Subsurface water is not anticipated to adversely affect site development, provided that the
recommendations contained in this report are incorporated into final design and
construction. These observations reflect site conditions at the time of our investigation and
do not preclude future changes "n local groundwater conditions from excessive irrigation,
precipitation, or that were net obvious, at the time of our investigation.
Seeps, springs,, or other indications of a high groundwater level were not noted on the
subject property during the trnie of our field investigation. However, seepage may occur
locally (due to heavy precipitation or irrigation) in areas where fill sosls overlie silty or clayey
soils. Such soils may be encountered in the earth umits that exist onsite.
Buie Communities, Inc.
Lots 1 ar^d 10, Carisbad Airport Cents'
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March 20, 1998
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LIQUEFACTION
SeismicalDy-induced liquefaction is a phenomenon in which cyclic stresses, produced by
earthquake-induced ground motion, create excess pore pressures in soife. The soils may
thereby acquire a high degree of mobility, and lead to lateral movement, sliding, sand
boils, consolidation and settlement of loose sediments, and other damaging deformations.
This phenomenon occurs only below the waterteble; but after liquefaction has developed,
it can propagate upward into overlying, non-saturated soil as excess pore water dissipates.
Typically; liquefaction has a relatively low potential at depths greater than 45 feet and is
virtually unknown beiow a depth of 60 feet.
Liquefaction susceptibility is related to numerous factors and the following conditions
should be present for liquefaction to occur: 1) sediments must be relatively young in age
and not have developed a large amount of cementation: 2) sediments generally consist
of medium to fine gramed relatively cohesionless sands; 3) the sediments must have low
relative densfty; 4) free groundwater must be present in the sediment; and 5) the site must
experience a seismic event of a sufficient duraSon and magnitude, to induce straining of
soil particles.
Inasmuch as three of these five conditions do not have the potential to affect the site and
the entire site is underlain by dense formationaB materials, oiff evaluation indicates that the
potential: for liquefaction and associated adverse effects within the site is very low, even
with afutiure rise in groundwater levels.
LABORATORY TESTING
Laboratory tests were performed on representative samples of representative site earth
materials in order to evaluate their physical characteristics. Test procedures used and
results obtained are presented betow.
Classification
Soils were classified vesuaily in accordance to the Unified Soils Classification System. The
soil classifications are shown on the boring logs, Appendix B.
Maximum Density Test
The laboratory maximum dry densfty and optimum moisture content for the major soil type
was determined according to ASTM test method D-1557. Results otf this testing are
presented in the following table.
Buie Communities, Inc. W.O. 2407-A-SC
Lots 1 anc TO. Carlsbad Airpcrt Center March 20. 1998
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LOCATION
B-3 @ 0-2'
B-5 @ 0-2'
SOIL TYPE
Sandy Silt Brownish Gray
Sandy Silt, Brownish Gray
to Olive Gray
MAXIMUM DENSITY
(pd) *-'
114.0
114.5
- OPTIMUM &il^
MOISTURE CONTENTS^z''-^*&w:--^&%&#
15.0
15.0
Expansion Potential
Expansion index testing was performed on a representative sample of the fill materials in
general accordance with Standard 18-2 of the Uniform Building Code (International
Conference of Building Officials, 1997). Results are presented in the following table.
LOCATION
B-3 @ 0-2-
B-5 @ 0-2"
f SOIL TYPE
Sandy Silt, Brownish Gray
Sandy Silt, Brownish Gray
to Olive Gray
EXPANSION
INDEX
70
59
EXPANSION ?v
POTENTIAL .%!
Medium
Medium
Direct Shear Testing
Shear testing was performed on a remolded sample of site soil in general accordance with
ASTM test method D-3080. The sample was remolded to 90 percent relative compaction
at optimum moisture content. Test results are presented in the following table.
LOCATION
B-3CSO-21
COHESION (psf)
580
^INTERNAL FRICTION
26
R-Value Testing
A representative sample of the subgrade soils was obtained during the current study and
tested to determine its R-va!ue. The materials were thought to be typical and presumed
to be representative of the subgrade soils. Testing was performed in accordance with the
latest revisions to the Department of Transportation, State of California, Material &
Research Test Method No. 301. The test results on representative earth materials indicate
an R-value of 15 and the test data is presented in Appendix C.
Buie Communities, Inc.
Lots 1 and 10. Ca/lsbad Aircort Center
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March 20. 1998
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Soluble Suffates/oH ResistivitY
A typical sample ..of the site materials was analyzed for soluble sulfate content and
corrosion to ferrous metals. The results are as follows:
LOCATION _"
B4 @ 0-2'
SOLUBLE
SULFATES
Ong/kg)
3,224
pH
5.2
, -r
RESISTIVITY rC
SATURATED f-V
(ohms-cm) -^-s-
205
Based upon the soluble sulfate test results (UBC range for severe suffate exposure is 1,500
to 10.OOO ppm solubfe [SO4] in water), the site soils have a high sutfate exposure potential
for corrosion to concrete. In addition, pH and resistivity tests were performed, which
indicate site soils are acidic and have a severe corrosivity potential to ferrous metals.
Severely corrosive soils are considered to be less than 1,000 ohms-can. The laboratory
test results for corrosivity testing are presented in Appendix C.
DISCUSSION AND CONCLUSIONS
General
Based on our field exploration, laboratory testing and gedtechnical engineering analysis,
it is OUJT opinion that the subject lot appears suitable for the proposed commercial
development from a geotechnical engineering and geologic viewpoint, provided that the
recommendations presented in the following sections are incorporated finto the design and
construction phases of site development. The primary geotechnical concerns with respect
to the proposed development on the lot are:
Depth to competent bearing material.
Settlement of fill.
Expansion potentiaJ of site soils.
Corrosion potential of site soils.
Subsurface and perched water.
Regional seismic activity.
The recommendations presented herein consider these as well as other aspects of the site.
The engineering analyses performed concerning site preparation and the
recommendations presented herein have been completed using the irmormation provided
and ob-taired during cur field work, as well as information provided to this office with
regard to grading (Appendix A). In the event that any significant changes are made to
proposed site development, the conclusions and recommendations contained an this
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report shall not be considered valid unless the changes are reviewed and the
recommendations of this report verified or modified in writing by this office. Foundation
design parameters are considered preliminary until the foundation design, layout, and
structural loads are provided to this office for review.
Earth Materials
Existing Fill
Existing fill materials within 11/2 feet of existing pad grade are generally weathered/eroded,
loose/soft, and/or do not meet the current industry minimum standard of 9O percent (or
greater) relative compaction. Based on our visual, tactile, and field density testing, the
relative compaction of existing fill appears to be generally at or above the current industry
minimum standard of 90 percent with fill soils generally moist and dense at depths below
2 feet Previous site work performed during rough grading of the lot (Moore &Taber, 1987)
has indicated that fill onsite was compacted to the minimum industry standards.
Bedrock
Formational materials will be encountered during site earthwork. Existing bedrock
materials within 1 foot of existing pad grade are generally loose/soft and/or do not meet
the current industry minimum standard of 90 percent (or greater) relative compaction.
Below 1 foot, these materials are considered competent for support of settlement-sensitive
structures in their existing state.
Potential Settlement of Fill
Lot 1: The existing fill on Lot 1 is anticipated to vary in thickness from approximately 0 to
24 feet within the proposed "footprint" perimeter of the building. This fill was placed to its
present configuration during mass grading of the Carlsbad Airport Center (Moore & Taber,
1987). Settlement may be considered substantially (on the order of 90 percent) completed
because the fill consists primarily of sand and has reached its maximum height/depth
approximately 12 years ago. However, the silty and clayey fraction of the fill may continue
to settle, due in part, to long-term compression, new building loads and continued
landscape irrigation at the surface. Recommendations for mitigation of this condition are
presented under "Overexcavation" herein.
Lot 10: Formational materials occur at existing grade throughout the lot. If a transition
cut/fill condition is created during grading, recommendations are presented herein for
overexcavation.
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Expansion Potential
Our experience, in the site vicinity and laboratory test results indicate that soils with a
medium expansion potential underlie the site. This should be considered during project
design. Foundation design and construction recommendations are provided herein for
medium expansion potential classifications.
Corrosion Potential
Our laboratory test results indicate that the site materials have a high sulfate exposure for
corrosion to concrete, have an acidic pH, and have a severe potential for corrosion to
exposed steel.
Subsurface and Surface Water
Subsurface and surface water, as discussed previously, are not anticipated to affect site
development, provided that the recommendations contained in this report are incorporated
into final design and construction and that prudent surface and subsurface drainage
practices are incorporated into the construction plans. Perched groundwater conditions
along fill/bedrock contacts and along zones of contrasting permeabilities should not be
precluded from occurring in the future due to site irrigation, poor drainage conditions, or
damaged utilities. Should perched groundwater conditions develop, this office could
assess the affected area(s) and provide the appropriate recommendations to mitigate the
observed groundwater conditions.
The groundwater conditions observed and opinions generated were those at the time of
our investigation. Conditions may change with the introduction of irrigation, rainfall, or
other factors that were not obvious at the time of our investigation.
Regionai Seismic Activity
The seismicity acceleration values provided herein should be considered during the design
of the proposed development.
EARTHWORK CONSTRUCTION RECOMMENDATIONS
General
All grading should conform to the guidelines presented in Appendix Chapter A33 of the
Uniform Building Code (adopted and current edition), the requirements of the City of
Carlsbad, and the Grading Guidelines presented in this report as Appendix D, except
where specifically superseded in the text of this report. Prior to grading GSl's
representative should be present at the preconstruction meeting to provide additional
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grading gufdefhes, if needed, and review the earfriwork schedule. Earthwork beyond She
limits of the surficial, remedial overexcavations or those indicated on the grading pftan
should be reviewed by $ie geologist and/or geotechnical consultant prior to and foflowong
these additSonai removals.
During earthwork construction all site preparation and the general grading procedures of
the contractor shoukJ be observed and the fill selectively tesSed by a representative^ of
GSI. If unusual or unexpected conditions are exposed in the field or if modifications are
proposed to tfie rough grade or precise grading plan, they should be reviewed by tihis
office and fif warranted,, modified and/or additional recommendations wilE be offered. All
applicable requirements of local and national construction and general industry safety
orders, the Occupational Safety and Health Act and the Construction Safety Act should
be met GSI does not consult in the area of safety engineering. Excavations into the
granular material on this site may be unstable.
Site Preparation
Debris, vegetation, and other deleterious material should be removed from tthe
improvements) area prior to the start of construction.
Removals (Unsuitable Surficial Materials)
AH existangfiil materials within the area of the proposed development shouSd be removed.
The lateral extent of these removals should be determined by a 1:1 (horizontal to vertical}
projection outward from the edge of tthe proposed structure afi planned grades at the base
of the removaS zone.
Following tfnese removals, the bottom areas approved to receive fill should first be scarified
in two perpendicular directions and moisture conditioned (at or above the soils optimum
moisture content) to a depth of 12 inches and recompacted to a minimum 90 percent
relative compaction JASTM D-1557). These conditions should be tested by a
representative of our firm.
If encountered during excavation of utilities or footings, oversized material's may increase
excavation difficulty. Treatment of unsuitable materials (removal and recompaction) should
be considered.
Over excavation
Lot1
Formatonal materials occur at, or near, existing grade withiin the portions cf the tot. Tc
mitigate for the potential of differential settlement- we recommend that overexcavation be
performed: or cut areas, and nil areas with insufficient underlying fill materials. This
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overexcavation should be performed on building pad areas and areas 10 feet outside
outer-most foundation elements to produce a minimum 5-foot fill blanket
Following the 5-foot overexcavation, the bottoms should be tested by a GSI representative
for a minimum 90 percent compaction and optimum moisture content. If the materials do
not meet the minimum requirements, further removals will be recommended. Subsequent
to all recommended removals, the bottoms areas approved to receive fill should first be
scarified in two perpendicular directions and moisture conditioned (at or above the soils
optimum moisture content) to a depth of 12 inches and compacted to a minimum 90
percent relative compaction.
Lot 10
Formational materials occur at existing grade throughout the lot. If a transition cut/fill
condition is created during grading, overexcavation should be performed on cut areas, and
fill areas with insufficient underlying fill materials. This overexcavation should be performed
on building pad areas and areas 4 feet outside outer-most foundation elements to produce
a minimum 4-foot fill blanket. This assumes a maximum 2-foot footing embedment If
embedments are greater than 2 feet, the overexcavation should be increased to a
minimum of 2 feet beyond the bottom of the footing and 6 feet laterally beyond the width
of the footing.
Following overexcavation, the bottoms areas approved to receive fill should first be
scarified in two perpendicular directions and moisture conditioned (at or above the soils
optimum moisture content) to a depth of 12 inches and compacted to a minimum 90
percent relative compaction.
Fill Placement
Subsequent to ground preparation, onsite soils may be placed in thin (6±inch) lifts,
cleaned of vegetation and debris, brought to a least optimum moisture content, and
compacted to achieve a minimum relative compaction of 90 percent. Oversized cobbles
and boulders (8 to 24 inches), generated as the result of the remedial earthwork should
be placed outside of the limits of the building in landscape areas or a pre-designated
disposal area.
If fill materials are imported to the site, the proposed import fill should be submitted to
GSI, so laboratory testing can be performed to verify that the intended import material is
compatible with onsite material. At least three business days of lead time should be
allowed by builders or contractors for proposed import submittal's. This lead time will allow
for particle size analysis, specific gravity, relative compaction, expansion testing, and
blended import/native characteristics as deemed necessary.
Buie Communities, Inc. W.O. 2407-A-SC
Lots 1 and 10, Carlsbad Airport Canter March 20,1998
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GeoSoils, Inc.
Erosion Control
Onsite soils and bedrock materials have a moderate erosion potential. Use of hay bates,
silt fences, and/or sandbags should be considered, as appropriate during construction.
Temporary grades should be constructed to drain at a minimum of 1 to 2 percent to a
suitable temporary or permanent outlet. Freeze grades should be evaluated by the design
civil engineer to reduce concentrated flows to less than 6 feet per second (Amimotox 1981)
and into lined or landscaped swales. Evaluation of cuts during grading will be necessary
in order to identify any areas of loose or nora-cohesive materials. Should any significant
zones be encountered during earthwork conslnjction, adcStional remedial grading may be
recommended; however, only the remedial raeasures discussed herein are anticipated at
this time.
FOUNDATION RECOMMENDATIONS
The conclusions and recommendations contained in this report are for Lots 1 and to only.
In the event that the information concerning t&ie proposed development plan is not correct
or any changes in the design, location, or loading conditions of the proposed structure are
made, the conclusions and recommendations shall not be considered valid unless the
changes are reviewed and conclusions of tfms report are modified or approved in writing
by this office.
The information and recommendations presented in this section are considered minnmums
and are not meant to supersede design(sf by the project structural engineer or civil
engineer specializing in structural design. Upon request GSI could provide additional
consultation regarding soil parameters, as related to foundation design. They are
considered preliminary recommendations for proposed construction, in consideration of
our field investigation, laboratory testing, arnd engineering analysis.
Preliminary Foundation Design
Our review, field work, and laboratory testing indicates tnat onsite soils have a nuedium
expansion potential; however, our experience indicates that soils within the Delmar
Formation with a high expansion potential may be encountered during grading.
Preliminary recommendations for foundation design and construction for both medium and
high are presented below. Final foundation recommendations should be provided at the
conclusion of grading based on laboratory testing of fill materials exposed at finish; grade.
Bearing Value
1. The foundation systems should be designed and 'Constructed in accordance with
guidelines presented in the latest edition of the Uniform Building Cede (International
Conference of Building Officials, 19S7).
Buie Communities, Inc. W.C. 2«Q7-A-SC
Lots 1 and 10, Carlsbad Airport Center March 20. *998
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GeoSoils, Inc.
2. An allowable bearing value of 1500 pounds per square foot may be used for design
of continuous footings 12 inches wide and 24 inches deep and for design of
isolated pad footings.24 inches square and 24 inches deep founded entirely into
compacted fill pi competent formational material and connected by grade beam or
tie beam in ate least one direction. This value may be increased by 200 pounds
per square foot for each additional 12 inches in depth to a maximum value of 2000
pounds per square foot. The above values may be increased by one-third when
considering short duration seismic or wind loads. No increase, in bearing, for
footing width is recommended.
Lateral Pressure
1. For lateral sliding resistance, a 0.30 coefficient of friction may be utilized for a
concrete to soil contact when multiplied by the dead load.
2. Passive earth pressure may be computed as an equivalent fluid having a density of
250 pounds per cubic foot with a maximum earth pressure of 2000 pounds per
square foot.
3. When combining passive pressure and frictional resistance, the passive pressure
component should be reduced by one-third.
4. All footings should maintain a minimum 7 foot horizontal set back from the base of
the footing to any descending slope. Footings for structures adjacent to retaining
wails should be deepened so as to extend below a 1:1 projection upward from the
bottom inside edge of the wall stem. Alternately, walls may be designed to
accommodate structural loads from buildings or appurtenances as described in
retaining wail section of this report.
Construction
The following foundation construction recommendations are presented as a minimum
criteria from a soils engineering standpoint. The onsite soils expansion potentials are
generally in the medium range (expansion index 51 to 90); however, soils in the high range
(expansion index 91 to 120) may be encountered during grading. Recommendations by
the project's design-structural engineer or architect, which may exceed the soils engineer's
recommendations, should take precedence over the following minimum requirements.
Final foundation design will be provided based on the expansion potential of the near
surface soils encountered during grading.
Medium Expansion Potential (Expansion Index 51 to 90)
1. Exterior and interior footings should be founded at a minimum depth of 18 inches
for two-story loads and 24 inches below the lowest adjacent ground surface for
Buie Communities, Inc. W.O. 2407-A-SC
Lots 1 and 10, Carisbad Airport Center March 20. 1998
File: e:\wp7»24002407a.pgt Page 15
GeoSoils, Inc.
three-story loads. All footings should be reinforced with two No. 4 reinforcing bars,
one placed near the top and one placed near the bottom of the footing. Footing
widths should be as indicated in the Uniform Building Oode (International
Conference of Building Officials, 1994).
2. A grade beam, reinforced as above, and al least 12 inches wide should be provided
across large (e.g. garage) entrances. The base of the grade beam should be at the
same elevation as the bottom of adjoining footings.
3. Concrete slabs, where moisture condensation is undesirable, should be underlain
with a vapor barrier consisting of a minimum of 6 mil polyvinyl chitaride or equivalent
membrane with all laps sealed. This membrane should be covered above and
below with a minimum of 2 inches of sand (total of 4 inches) to aid in uniform curing
of the concrete and to protect the membrane from puncture.
4. Concrete slabs should be a minimum of 4 inches thick, and should be reinforced
with 6 inch by 6 inch, No. 6 by No. 6 (6x6 - W2.9 x W2.9) welded-wire mesh or No.
3 reinforcing bar at 24 inches on center, if welded wire mesh is selected. No. 3
reinforcing bar at 24 inches on center should be doweled between the exterior
footing and 3 feet into the slab. All slab reinforcement should be supported to
ensure placement near the vertical modpoint of the concrete. "Hooking1 the wire
mesh is not considered an acceptable method of positioning tfoe reinforcement.
5. Garages are not anticipated, but if constructed, slabs should be poured separately
from the structural footings and quartered with expansion jofrnrts or saw cuts. A
positive separation from the footings should be maintained wfith expansion joint
material to permit relative movement.
6. Presaturation is recommended for these soil conditions. The moisture content of
the subgrade soils should be equal to or greater than 120 percent of optimum
moisture content to a depth of 18 inches below grade in the stab areas. Prior to
placing visqueen or reinforcement, soil presaturation should be verified by this office
within 72 hours of pouring slabs.
High Expansion Potential (Expansion Index 91 to 120)
1. Exterior and interior footings should be founded at a minimum depth of 24 nnches
for two-story loads and 30 inches below the lowest adjacent ground surface for
three-story leads. All footings should be reinforced with four Ncx 4 reinforcing bars,
two placed near the top and two placed near the bottom of the footing. Footing
widths should be as indicated in the Uniform Building Code (International
Conference of Building Officials, 1994).
Buie Communities, Inc. W.O. 24O7-A-SC
Lets 1 and 10. CarlsbaC Airport Center March 20, 1998
Fie: e: *or2400v.2407a^gt Page 16
GeoSoils, Inc.
2. A grade beam, reinforced as above, and at least 12 inches wide should be provided
across large (e.g. garage) entrances. The base of the grade beam should be at the
same elevation as the bottom of adjoining footings.
3. Concrete slabs, where moisture condensation is undesirable, should be underlain
with a vapor barrier consisting of a minimum of 6 mil potyvinyl chloride or equivalent
membrane with all laps sealed. This membrane should be covered above and
below with a minimum of 2 inches of sand (total of 4 inches) to aid in uniform curing
of the concrete and to protect the membrane from puncture.
4. Concrete slabs should be a minimum of 4 inches thick, and should be reinforced
with 6 inch by 6 inch, No. 6 by No. 6 (6x6 - W2.9 x W2.9) welded-wire mesh or No.
3 reinforcing bar at 18 inches on center. If welded wire mesh is selected, No. 3
reinforcing bar at 18 inches on center should be doweled between the exterior
footing and 3 feet into the slab. All slab reinforcement should be supported to
ensure placement near the vertical midpoint of the concrete. "Hooking" the wire
mesh is not considered an acceptable method of positioning the reinforcement.
5. Garages are not anticipated, but if constructed, slabs should be poured separately
from the structural footings and quartered with expansion joints or saw cuts. A
positive separation from the footings should be maintained with expansion joint
material to permit relative movement.
6. Presaturation is recommended for these soil conditions. The moisture content of
the subgrade soils should be equal to or greater than 120 percent of optimum
moisture content to a depth of 24 inches below grade in the slab areas. Prior to
placing visqueen or reinforcement, soil presaturation should be verified by this office
within 72 hours of pouring slabs.
CORROSION AND CONCRETE MIX
Based on the sutfate levels and corrosion potential for exposed concrete, foundations
should be constructed using Type V concrete; and per the UBC, 4,500 psi concrete is
required. The design criteria presented in Table 19-A2 and 19-A3 of the UBC (1997
edition) should be followed. Upon completion of grading, additional testing of soils
(including import materials) should be considered prior to the construction of utilities and
foundations. Because of the high acidity of the soils and the severe corrosion potential,
further evaluation should be obtained from a qualified corrosion engineer.
Buie Communities, Inc. W.O. 2407-A-SC
Lets 1 and 10, Carlsbad Airport Center March 20, 1998
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GeoSoils, Inc.
RETAINING WALL RECOMMENDATIONS
General
The equivalent fluid pressure parameters provide for either the use of native or low
expansive select granular backfill to be utilized behind the proposed wails. The low
expansive granular backfill, should be provided behind the wall at a 1:1 (h:v) projection
from the heei of the foundation system. Low expansive fill is Class 3 aggregate baserock
or Class 2 permeable rock. Wall backfilling should be performed with relatively.light
equipment within the same 1:1 projection (i.e., hand tampers, walk behind compactors).
Highly expansive soils should not be used to backfill any proposed walls. During
construction, materials should not be stockpiled behind nor in front of walls for a distance
of 2H where H is the height of the wall.
Foundation systems for any proposed retaining walls should be designed in accordance
with the recommendations presented in the Foundation Design section of this report.
Building walls, below grade, should be water-proofed or damp-proofed, depending on the
degree of moisture protection desired. All walls should be property designed in
accordance with the recommendations presented below.
Some movement of the walls constructed should be anticipated as soil strength
parameters are mobilized. This movement could cause some cracking depending upon
the materials used to construct the wall. To reduce the potential for wall cracking, walls
should be internally grouted and reinforced with steel. To mitigate this effect, the use of
vertical crack control joints and expansion joints, spaced at 20 feet or less along the walls
should be employed. Vertical expansion control joints should be infilled with a flexible
grout. Wall footings should be keyed or doweled across vertical expansion joints. Walls
should be internally grouted and reinforced with steel.
Restrained Walls
Loading Dock Wail
It is recommended that loading dock walls be designed for restrained conditions (indicated
below), where adjacent to the proposed site building. Loading dock walls should be
designed to resist lateral earth pressure and any additional lateral pressures caused by
surcharge loads on the anticipated adjoining slab surface. Approximately up to !4 of
surcharge loads on the truck loading dock slab may be added as a uniform load in the
back of the loading dock wall. However, the structural engineer or civil engineering
specializing in structural design should review and evaluate the type of wall connection(s)
and the condition of the wall (restrained or cantilever).
Buie Communities, Inc. W.O. 2407-A-SC
Lots 1 and 10, Carlsbad Airport Center March 20,1998
File: e:\wp7\2400*2407a.pgt Page 18
GeoSoils, Inc.
Other Walls
Any retaining walls that will be restrained prior to placing and compacting backfill material
or that have re-entrant or male comers, should be designed for an at-rest equivalent fluid
pressures (EFP) of 65 pcf, plus any applicable surcharge loading. This restrained-wall,
earth pressure value is for select backfill material only. For walls that are restrained and
backfilled with native low to medium expansive soils, an EFP of 75 pcf, plus applicable
surcharge loads should be used. For areas of male or re-entrant comers, the restrained
wall design should extend a minimum distance of twice the height of the wall laterally from
the comer.
Building walls below grade or greater than 2 feet in height should be water-proofed or
damp-proofed, depending on the degree of moisture protection desired. The wall should
be drained as indicated in the following section. A seismic increment of 10H (uniform
pressure) should be considered on walls for level backffll, and 20H for sloping backfill of
2:1, where H is defined as the height of retained material behind the wall. For structural
footing loads within the 1:1 zone of influence behind wall backfill, refer to the following
section.
Cantitevered Walls
These recommendations are for cantilevered retaining walls up to 10 feet high. Active
earth pressure may be used for retaining wall design, provided the top of the wall is not
restrained from minor deflections. An empirical equivalent fluid pressure approach may
be used to compute the horizontal pressure against the wail. Appropriate fluid unit weights
are provided for specific slope gradients of the retained material. These do not include
other superimposed loading conditions such as traffic, structures, seismic events,
expansive soils, or adverse geologic conditions.
For cantilever retaining walls greater than 4 feet in height, a seismic increment of 10H
(uniform pressure) for level backfill and 20H for backfill sloped at 2:1 behind the walls
should be considered. For cantilever walls, these seismic loads should be applied at 0.6
H up from the bottom of the wall. If traffic is within a distance H behind any wall or a 1:1
projection from the heel of the wall foundation a pressure of 100 psf per foot in the upper
5 feet should be used. Structural loads from adjacent properties and their influence on site
walls should be reviewed by the structural engineer, if within a 1:1 projection behind any
site wall. However, for preliminary planning purposes, one third of the footing contact
pressure should be added to the wall in pounds per square foot below the bearing
elevation and for a distance of three times the footing width along the wall alignment.
Alternatively, a deepened footing beyond the 1:1 projection {up from the heel) behind the
wall may be utilized.
Buie Communities, Inc. W.O. 2407-A-SC
Lots 1 and 10. Carlsbad Airport Center March 20,1998
He: s:'.wc7\2400\2407a.pst Page 19
GeoSoils, Inc.
SURFACE SLOPE OF
RETAINED MATERIAL
(horizontal to vertical)
Level**
2to1
EQUIVALENT
FLUID WEIGHT
5{PCF) '
33
45
*To be increased by traffic, structural surcharge
and seismic loading as needed.
**Level walls are those where grades behind
the wall are level for a distance of 2H.
Wall Backfill and Drainage
All retaining walls should be provided with an adequate backdrain and outlet system
(a minimum two outlets per wall and no greater than 50 feet apart), to prevent buildup of
hydrostatic pressures and be designed in accordance with minimum standards presented
herein. See site wall drain options (Figure 3, Figure 4, and Figure 5). Drain pipe should
consist of 4-inch-diameter perforated schedule 40 PVC pipe embedded in gravel. Gravel
used in the backdrain systems should be a minimum of 3 cubic feet per lineal foot of 3/a-
to 1-inch clean crushed rock wrapped in filter fabric (Mirafi 140 or equivalent) and 12
inches thick behind the wall. Where the void to be fitted is constrained by lot lines or
property boundaries, the use of panel drains (Mirafi 5000 or equivalent) may be considered
with the approval of the project geotechnical engineer. The surface of the backfill should
be sealed by pavement or the top -18 inches compacted to 90 percent relative compaction
with native soil. Proper surface drainage should also be provided. Weeping of the walls
in lieu of a backdrain is not recommended for walls greater than 2 feet in height. For walls
2 feet or less in height, weepholes should be no greater than 6 feet on center in the bottom
coarse of block and above the landscape zone.
A paved drainage channel (v-ditch or substitute), either concrete or asphaltic concrete,
behind the top of the walls with sloping backfill should be considered to reduce the
potential for surface water penetration. For level backfill, the grade should be sloped such
that drainage is toward a suitable outlet at 1 to 2 percent.
Retaining Wall Footing Transitions
Site walls are anticipated to be founded on footings designed in accordance with the
recommendations in this report. Wall footings may transition from formational bedrock to
gravelly fill to select fill. If this condition is present the civil designer may specify either:
a) If transitions from rock fill to select fill transect the wall footing alignment at an angle
of less than 45 degrees (plan view), then the designer should perform a minimum
2-foot overexcavation for a distance of two times the height of the wall and increase
Buie Communities, Inc.
Lots 1 and 10, Carlsbad Airport Center
File: e:\wpA2400\2407a.pgt
W.O. 2407-A-SC
March 20, 1998
Page 20
GeoSoils, Inc.
r Ccc crcin (c^t off)
Tc" ceicw sail line
Manufactured drcinoce
Geocomposite drain
( Mira drain 5000 or
equivalent )
Site rstcininc well
(structure! assign
by ethers)
Note: Filter fcbric wraps ccmpleteiy
around perforated P'pe
behind core materiel, core
mcteric! wraps benea;."-
bottom or pipe.
4" die. min. perforated
pipe placed with holes
down end sloped ct 1 —2%
to suitable outlet
4" min. crcnulcr materiel —
(class 2 permeable or
3/5—1" clean crushed
rock wrapped in c
filter fabric)
.-cvement seccicn per —;
GSi recommendations !
^^•'?iS/fi&&
'— V/ci: fcoc-nc
(cesicnec by ethers)
SCHEMATIC OF SITE WALL DRAIN
OPTION A Rgure3
HATF 3/98 w.o.2407-A-SC
Geotechnical • Geologic • Environmental
FORM 89/22
12" thick (min.) drain rock
(class 2 permeable) or
other acceptable granular
material. 1/8-1" clean
crushed rock wrapped in
a filter fabric (Mirafi 140
or equivalent)
4" die. min. perforated
pipe placed with holes
down ana sloped at 1—2%
to c suitable outlet
I—Ccp drain (cut off)
L IS" be!ow sail line
Sice retaining well
(structural design
by others)
Pavement section per
C-Si recomendations —
Finished lot surface
IX
4" Min. —
4
it
\
f -
Min. — ^-
. ' «
kh*-i '' L i 'of. i
- ' ' • " ' *-
- * * | 0' " • * 1 .
* »^' . i t
1 a *
-^ — 4"• • » •**• » 1 ••
^•! ' ' °' "° J« * ' • • • "*
l*a * • ' * • '• . 1 o • * ,
Win. ' ' ° '. » i ' a• *i" * *•
i «J . - * Lv . , " / -
-Vc.il fee ting
(designed fcy ethers)
S?:nc.
SCHEMATIC OF SITE WALL DRAIN
OPTION B Figure 4
DAJE 3/98 W.O. NO.2407-A-SC
Geotechnical • Geologic • Environmental
FORM 89/22
If finished surface is within*
S" cf tea of fcacinc wcil
shell be ct 6' Tntervcis clone
the Eencth of fchre wail end
Iccctsc ct the levei of the
bcttcm course cf blccx. Trr,e
drcins shell be 4" in diameter.
:—Cao drcrji'(c'jt cff)
• IS" befc-w soil .'ireT
\r~
iite retcinfng wcil
(structure! assign
by others)
2A" thick (min.) drcin rccx
(cicss 2 permecbiie) cr
ether acceptable crcnulcr
m c terseI, 1 /S— S" dec n
crushed rccx wrapped tr*.
c fHter fcbric (Mircfl 140
cr ecuJvcient)
Wcterprccnuic
1 o
f ' ^ *"• ' -, I a , e ' I
* I r> J'» » ** • '• \.r ' '. • rf .« - ^i "".;..-" i a°.
".«. V- & ^« ^' ' + *
^
i.-
\I | f ^^^ ^ -
^ "\ ^\ ^GeoSoils, Inc
SCHEMATIC OF SITE WALL DRAIN
OPTION C Figure 5
DATE 3/98^W.O.2407-A-SC
Geotechnical • Geologic • Environmental
FORM 89/22
overexcavation until such transition is between 45 and 90 degrees to the wall
alignment.
b) Increase of the amount of reinforcing steel and wall detailing (i.e., expansion joints
or crack control joints) such that an angular distortion of 1/360 for a distance of 2H
(where H=wall height in feet) on either side of the transition may be
accommodated. Expansion joints should be sealed with a flexible, non-shrink
grout.
c) Embed the footings entirely into a homogeneous fill.
PRELIMINARY PAVEMENT DESIGN
A representative sample of the subgrade soils was obtained and tested to determine the
R-value. The material was thought to be typical and presumed to be representative of the
subgrade soils. Testing was performed in accordance with the latest revisions to the
Department of Transportation, State of California, Material & Research Test Method No.
301. For planning purposes, pavement sections consisting of asphaltic concrete over
base and full depth Portland cement concrete pavement (PCCP) are provided. Anticipated
asphaltic concrete (AC) pavement sections are presented as follows.
ASPHALTIC CONCRETE PAVEMENT
TRAFFIC AREA
Parking Stalls
Parking Stalls
Traffic Areas
Traffic Areas
TRAFFIC , ""
INDEX® -x-
(Tl, Assumed)
4.5
5.0
5.5
6.0
SUBGRADE
-•R--VALUE_
15
15
15
15
-T i tA.c7
THICKNESS12'
(Inches)
4.0
4.0
4.0
4.0
CLASS 2 AGGREGATED :
BASE THICKNESS*1* -
(inches)
6.0W
6.0W
8.0
9.5
"'Denotes standard Caltrans Class 2 aggregate base R >_78, SE >_22).
raCtty of Carlsbad minimum AC thickness is 4 inches.
^Tl values have been assumed for planning purposes herein and should be confirmed by the design
team during future plan development
(*While minimum design thickness may be less. GSI does not recommend the use of less than 6 inches of
base rock over project site soil.
Buie Communities, Inc.
Lots 1 and 10, Car;sbad Airport Center
File: e:'.v,D7\.2400\24C7a.pgt GeoSoilSj Inc.
W.O. 2407-A-SC
March 20,1998
Page 24
Portland cement concrete pavement sections are presented as follows:
. ;
TRAFFIC
AREA
Parking
SSalls
Parking
Stalls
Parking
Stalls
Parking
Stalls
Parking
Stalls
Traffic
Atraas
Traffic
Atreas
Traffic
Atreas
Traffic
Areas
Traffic
Aireas
"•-.-="• .,'^^fm- iW^Sffi. CONCRETE
AVERAGE DAILY 111
TRircKTRAfHCfl
{ADTT assumed) /
10
25
100
300
500
10
25 f
100
300
500
SUBGRADE
:,- "R-. A*
VAUJEK
15
15
15
15
15
15
15
15
15
15
PAVERCHr - ilfiJ^
AXLE~
LOAD
CATEGORY
fight
fight
Bght
fight
Sght
medium/heavy
medium/heavy
medium/heavy
median/heavy
medium/hiBavy
P.C.C.m
THICKNESS
C")
65
6i
7.0
7.0
7.0
7J5
75
8.0
8.5
8^
«f^B™ •«!=
CLASS 2W""
AGGREGATE,
BASE s
THICIWESS-±£S^l " \-On)
-
-
-
-
-
4.0
4.0
4.0
4.0
4.0
""'Concrete shal be 560-C-3250 minimum. Assumes the construction of concrete shoulders.
aADTT values have been assumed fcr planning purposes herein and shouid be confirmed by the
design team during future plan development
^For truck lanes and ramps, a 4-iinch minimum Isyer of Class 2 aggregate base may be considered
beneath trie concrete paving. In order to improve performance of concrete pavement in parking
areas, the 4-inch base layer may also be considered in these areas. Transport thickness details will
be needed between traffic areas and oarkina lanes.
Design of truck loading docks should utilize guidelines provided for truck lanes and ramps
vfith special detaining for edges and jointing. Detailing of PCCP should be performed by
the Civil Designer and should include ;cac transfer jcints and crack control joints for truck
traffic areas. If requested, GS1 should review the minimum expansion and crack control
Euie Communities, Inc.
Lrts " ana 10, Csrisbad Airport Center
Fie; e:-\wp72400\2^07a.ngl
W.O. 2407-A-SC
March 20, 1998
Page 25
GeoSoils, Inc.
joint spacings. Trash enclosures areas should be designed per the minimum standards
of the City of Carlsbad. GSI does not recommend the use of an average daily truck traffic
(ADTT) value of less than 25 for any pavement section, unless the ADTT significantly less
than 25 is certified by a civil engineer specializing in traffic engineering.
The recommended pavement sections provided above are meant as minimums. If thinner
or highly variable pavement sections are constructed, increased maintenance and repair
could be expected. If the average daily traffic (ADT) or ADTT increases beyond that
intended, as reflected by the traffic index used for design, increased maintenance and
repair could be required for the pavement section.
Pavement grading recommendations are presented in Appendix E. Subgrade preparation
and aggregate base preparation should be performed in accordance with those
recommendations, and the minimum subgrade (upper 12 inches) and Class 2 aggregate
base compaction should be 95 percent of the maximum dry density (ASTM D-1557). If
adverse conditions (i.e., saturated ground, etc.) are encountered during preparation of
subgrade, special construction methods may need to be employed.
FLATWORK AND ASSOCIATED IMPROVEMENTS
1. Planters and walls should not be tied to building(s).
- 2. Driveways, sidewalks, and patios adjacent to the building(s) should be separated
from the building(s) with thick expansion joint filler material. In addition, all
sidewalks and driveways should be quartered and poured with expansion joints no
farther apart than 8 feet for 4-inch slabs or 10 feet for 5-inch slabs, respectively. To
improve the performance of the driveway and/or sidewalks constructed on the
expansive soils, consideration should be given to pre-saturation of the soils prior to
placement of driveways and sidewalks to 130 percent of optimum moisture.
Consideration should additionally be given for the areas of the driveways and
sidewalks adjacent to planters, lawns, and other landscape areas to have thickened
edges, such that the edge is 4 to 6 inches thick and at least 6 inches below the
adjacent landscaping zone (section).
3. Overhang structures should be structurally designed with continuous footings or
grade beams tied in at least two directions. Footings that support overhang
structures should be embedded a minimum of 24 inches from the lowest adjacent
finished subgrade.
4. Any masonry landscape walls that are to be constructed throughout the property
should be fully grouted and articulated in segments no more than 20 feet long.
Buie Communities, Inc. W.O. 2407-A-SC
Lots 1 anc 10. Carlsbad Airport Center March 20,1998
File: e:\wp72iOO'-2407a.pgt Page 26
GeoSoils, Inc.
5. Utilities should be enclosed within a closed vault or designed with flexible
connections to accommodate differential settlement and expansive soil conditions.
6. Finish grade (Precise Grade Plan) on the lot should provide a minimum of 1 to 2
percent faJI to the street. It should be kept in mind that drainage reversals could
occur if relatively flat yard drainage gradients are not maintained due to landscaping
work, modifications to fiatwork, or post-sale homeowner modifications.
Tile Flooring
Tile flooring can crack, reflecting cracks in the concrete slab below the tile. Therefore, the
designer should consider additional steel reinforcement of concrete slabs on-grade where
tile will be placed. The tile installer should consider installation methods that reduce
possible cracking of the tile such as slipsheets. Slipsheets or a vinyl crack isolation
membrane (approved by the Tile Council of America/Ceramic Tile Institute) is
recommended between tile and concrete slabs on grade.
Gutters and Downspouts
Consideration should be given to the installation of gutters and downspouts to collect roof
water that may otherwise infiltrate the soils adjacent to the structures. The downspouts
should be drained away from the foundation and collected in drainage swales or other
approved non-erosive drainage systems designed by a registered civil engineer
(specializing in drainage) to convey water away from the foundation. Gutters and
downspouts are not a geotechnical requirement, however, provided positive drainage is
maintained in accordance with the recommendations of the design civil engineer.
Exterior Slabs and Walkways
Exterior concrete slabs-on-grade (walkways, patios, etc.) should be constructed with a
minimum 4-inch thick slab, and reinforced with steel rebar or welded mesh. The
reinforcement should consist of No. 3 rebar placed at 12 inches on center in two
horizontally perpendicular directions (long axis and short axis), or 6x6-W2.9xW2.9 welded-
wire mesh. It is important for the performance of the slab that the reinforcing be located
near mid-slab thickness using chairs, supports, etc. Hooking is not an acceptable method
of reinforcement placement, and is not recommended.
Distortions on the exterior slab-on-grade due to expansive soils and proximity to slopes
may warrant additional mitigation. This may include crack control joints (4 to 6 feet
spacing in horizontally perpendicular directions (long axis and short axis)), and expansion
control joints at intervals 10 feet or less. Other considerations for mitigation may include
the use of thickened edges (see above) for slabs at the top of slopes, fiber mesh mixed
into the concrete, or pre-saturation of subgrade soils to 130 percent of optimum moisture
content, to a depth of 18 inches.
Buie Communities, Inc. W.O. 2407-A-SC
Lots 1 and 10, Carlsbad Airport Center March 20, 1998
F.e: e:'.wp7i2400\2i07a..pgt Page 27
GeoSoils, Inc.
Due to expansive soils, air conditioning (A/C) units should be supported by slabs that are
incorporated into the building foundation (PT slab) or constructed on a rigid slab with
flexible couplings for plumbing and electrical lines. A/C waste water lines should be
drained to a suitable outlet (see previous section).
Shrinkage cracks in concrete could become excessive if proper finishing and curing
practices are not followed. Finishing and curing practices should be performed per the
Portland Cement Association Guidelines. Mix design should incorporate rate of curing for
climate and time of year, sulfate content of soils, corrosion potential of soils, and fertilizers
used on site.
ADDITIONAL RECOMMENDA-nONS/DEVELOPMEfrfT CRFTERIA
Additional Site Improvements
If in the future, any additional improvements are planned for the site, recommendations
concerning the geological or geotechnical aspects of design and construction of said
improvements could be provided upon request this includes but not limited to appurtenant
structures.
This office should be notified in advance of any additional fill placement, regrading of the
site, or trench backfilling after rough grading has been completed. This includes any
grading, utility trench, and retaining wall backfills.
Erosion and Sedimentation Control
The objective of the National Pollutant Discharge Bimination System (NPDES)
requirements are to reduce (or eliminate) discharge of non-storrnwater runoff from
construction sites. One of the best management practices (BMP's) to mitigate significant
erosion from sites in the grading phase of construction is implementation of structural
containment devices, including but not limited to sandbags, retention basins, hay bales,
etc. BMP's should be developed prior to the start of mass grading. As described in the
General Permit, a Storm Water Pollution Prevention Plan (SWPPP) specific to the subject
development is required, and should include an erosion control plan presenting best
management practices (BMP's) for runoff control. The erosion control plan should be
exhibited on the grading plans. The SWPPP should be maintained until a post-
construction management plan is in effect These services would be provided by GSI
upon request.
Landscape Maintenance and Planting
Water has been shown to weaken the inherent strength of soil, and slope stability is
significantly reduced by overly wet conditions. Positive surface drainage away from graded
Buie Communities, Inc. W.O. 2407-A-SC
Lots 1 and 10. Carlsbad Airpcrt Center March 20,1S98
File: e:l,>«>72400l2407a.psi Page 28
GeoSollSj Inc.
slopes should be maintained and only the amount of irrigation necessary to sustain plant
life should be provided for planted slopes. Over-watering should be avoided. Onsite soil
materials should be maintained in a solid to semisolid state.
Brushed native and graded slopes (constructed within and utilizing onsite materials) would
be potentially erosive. Eroded debris may be minimized and surficiaJ slope stability
enhanced by establishing and maintaining a suitable vegetation cover soon after
construction. Plants selected for landscaping should be light weight, deep rooted types
that require little water and are capable of surviving the prevailing climate. Planting of Jarge
trees with potential for extensive root development should not be placed closer than 10
feet from the perimeter of the foundation or the anticipated height of the mature tree,
whichever is greater. It order to minimize erosion on the slope face, an erosion control
fabric (i.e. jute matting) should be considered.
From a geotechnicaJ standpoint, leaching is not recommended for establishing
landscaping. If the surface soils area processed for the purpose of adding amendments
they should be recompacted to 90 percent minimum relative compaction. Moisture
sensors, embedded into fill slopes, should be considered to reduce the potential of
overwatering from automatic landscape watering systems. The use of certain fertilizers
may affect the corrosion characteristics of soil. Review of the type and amount
(pounds per acre) of the fertilizers by a corrosion specialist should be considered.
Recommendations for exterior concrete fiatwork design and construction can be provided
upon request. If in the future, any additional improvements are planned for the site,
recommendations concerning the geological or geotechnical aspects of design and
construction of said improvements could be provided upon request. This office should be
notified in advance of any additional fill placement, regrading of the site, or trench
backfilling after rough grading has been completed. This includes any grading, utility
trench, and retaining wall backfills.
Drainage
Positive site drainage should be maintained at all times. Drainage should not flow
uncontrolled down any descending slope. Water should be directed away from
foundations and not allowed to pond and/or seep into the ground. Pad drainage should
be directed toward the street or other approved area. Landscaping should be graded to
drain into the street, or other approved area. All surface water should be appropriately
directed to areas designed for site drainage.
Roof gutters and down spouts are recommended to control roof drainage. Down spouts
should outlet a minimum of 5 feet from proposed structures or tightlined into a subsurface
drainage system. We recommend that any proposed open bottom planters adjacent to
proposed structures be eliminated for a minimum distance of 10 feet. As an alternative,
closed bottom type planters could be utilized. An outlet placed in the bottom of the
Buie Communities, Inc. W.O. 2407-A-SC
Lots 1 and 10, Carlsbad Airport Center March 20, 1998
File: e:\wp7'24OO\2407a.pgt Page 29
GeoSoils, Inc.
planter, could be installed to direct drainage away from structures or any exterior concrete
flatwork. Drainage behind top of walls should be accomplished along the length of the wall
with a paved channel drainage V-ditch or substitute.
Footing Trench Excavation
All footing trench excavations should be observed and approved by a representative of this
office prior to placing reinforcement. Footing trench spoil and any excess soils generated
from utility trench excavations should be compacted to a minimum relative compaction of
90 percent, if not removed from the site.
Trench Backfill
All excavations should be observed by one of our representatives and conform to OSHA
and local safety codes. Exterior trenches should not be excavated below a 1:1 projection
from the bottom of any adjacent foundation system. If excavated, these trenches may
undermine support for the foundation system potentially creating adverse conditions.
1. All utility trench backfill in slopes, structural areas and beneath hardscape features
should be brought to near optimum moisture content and then compacted to obtain
a minimum relative compaction of 90 percent of the laboratory standard.
Observations, probing and, if deemed necessary, testing should be performed by
a representative of this office to verify compactive efforts of the contractor.
2. Soils generated from utility trench excavations should be compacted to a minimum
of 90 percent (ASTM D-1557) if not removed from the site.
3. Jetting of backfill is not recommended.
4. The use of pipe jacking to place utilities is not recommended on this site due to the
presence of gravels and cobbles.
5. Bottoms of utility trenches should be sloped away from structures.
PLAN REVIEW
Final site development and foundation plans should be submitted to this office for review
and comment, as the plans become available, for the purpose of minimizing any
misunderstandings between the plans and recommendations presented herein. In
addition, foundation excavations and any additional earthwork construction performed on
the site should be observed and tested by this office. If conditions are found to differ
substantially from those stated, appropriate recommendations would be offered at that
time.
Buie Communities, Inc. W.O. 2407-A-SC
Lots 1 and 10, Carlsbad Airport Center March 20,1998
File: e:-,wp7\2400\2407a.pgt Page 30
GeoSoils, Inc.
APPENDIX A
REFERENCES
Appendix A
REFERENCES
Amimoto, Perry Y.( 1981, Erosion and sediment control handbook: Division of Mines and
geology, Department of Conservation, May.
Blake, Thomas F., 1997, EQFAULT computer program and users manual for the
deterministic prediction of horizontal accelerations from digitized California faults.
California, State of, 1967, Groundwater occurrence and quality: San Diego region,
Department of Water Resources, Bulletin 106-2, vol. II plates, dated June.
Eisenberg, LI., 1985, Depositional processes in the landward part of an Eocene tidal
lagoon, northern San Diego County in On the Manner of Deposition Of Eocene
Strata in Northern San Diego County, Abbott, P.L ed.: San Diego Association of
Geologists Guidebook, 98 pp.
Frankel, Arthur D., Perkins, David M., and Mueller, Charles s., 1996, Preliminary and
working versions of draft 1997 seismic shaking maps for the United States showing
peak ground acceleration (PGA) and spectral acceleration response at 0.3 and 1.0-
second site periods for the Design Basis Earthquake (10 percent chance of
exceedance in 50 years) for the National Earthquake Hazards Reduction Program
(NEHRP): U.S. Geological Survey, Denver, Colorado.
GeoSoils, Inc., 1996, Preliminary geotechnical evaluation, Lot 20, Carlsbad Oaks, Carlsbad
Tract 74-21, Carlsbad, California, W.0.1950-SC, January 8.
Greensfelder, R. W., 1974, Maximum credible rock acceleration from earthquakes in
California: California Division of Mines and Geology, Map Sheet 23.
Hart, E.W., 1994, Fault-rupture hazard zones in California: California Department of
Conservation, Division of Mines and Geology, Special Publication 42.
Housner, G. W., 1970, Strong ground motion in earthquake engineering, Robert Wiegel,
ed., Prentice-Hall.
International Conference of Building Officials, 1997, Uniform building code: Whittier,
California, vol. 1, 2, and 3.
Jennings, C.W., 1994, Fault activity map of California and adjacent areas: California
Division of Mines and Geology, Map Sheet No. 6, scale 1:750,000.
Kennedy. Michael P., and Peterson, Gary L, 1975, Geology of the San Diego metropolitan
area, California: California Division of Mines and Geology, Bulletin 200.
GeoSoils, Inc.
Krinitzsky, Ellis L, Gould, J.P., and Edinger, P.M., 1993, Fundamentals of earthquake
resistant construction: John H. Wiley & Sons, Inc., 299 p.
Moore & Taber, 1987, Report of geotechnical services, Carlsbad Tract No. 81 -46, Airport
Business Center, Unit No. 1, City of Carlsbad, California," Job No. 285-256,
February 25,1987, by Moore & Taber.
Naval Facilities Engineering Command, 1986a, Soil mechanics design manual 7.01,
Change 1: U.S. Navy, September.
, 1986b, Foundations and earth structures, design manual 7.02, Change 1: U.S.
Navy, September.
Petersen, Mark D., Bryant, WA, and Cramer, C.H., 1996, Interim table of fault parameters
used by the California Division of Mines and Geology to compile the probabilistic
seismic hazard maps of California.
Portland Cement Association (PCA), 1990, Thickness design of highway and street
pavements, computer program version 2.10.
Sadigh, K., Egan, J., and Youngs, R., 1987, Predictive ground motion equations reported
in Joyner, W.B., and Boore, D.M., 1988, "Measurement, characterization, and
prediction of strong ground motion", in Earthquake Engineering and Soil Dynamics
II, Recent Advances in Ground Motion Evaluation, Von Thun, J.L, ed.: American
Society of Civil Engineers Geotechnical Special Publication No. 20, pp. 43-102.
Sowers and Sowers, 1979, Unified soil classification system (After U. S. Waterways
Experiment Station and ASTM 02487-667) in Introductory Soil Mechanics, New
York.
United States Geological Survey, 1968, Encinitasy quadrangle, California-San Diego Co.,
7.5 minute series (topographic), photo revised 1975,1"=2000'.
, 1968, San Luis Rey quadrangle, California-San Diego Co., 7.5 minute series
(topographic), photo revised 1975,1"=2000'.
Buie Communities, Inc. Appendix A
File: e:\wpA Page 2
GeoSoils, Inc.
APPENDIX B
BORING LOGS
BORING LOG
GeoSoils, Inc.
WO/FCr-BUIE COMMUNITIES
Lots 1&10 CAC
Dapth Cft.)-
5-
-
-
10-
15-
"
Sample
*3m
s •*•I -01 \
• V'| •
-JH 3DL PC 3\ -34-iJ a
j]
! :i-
1 i !20-: :usesSumbo 1SM-
ML
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+- 11 •
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0 ;: C
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i
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3
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i
•
W-O. 2407-A-SC
^
BORING B-1 SHEET 1 OF 1
DATE EXCAVATED 2-27-98
SAMPLE METHOD: Hand Auger
^1
^
1 Standard Penetration Test
, ^ W&rer Seepage into note
\ Undisturbed, Ping Sampled
Description of Material
^
DELMAR FORMATION
@0', SILTY SANDSTONE, olive gray, wet, loose; very fine to
fine.
\@1'» grades to moist, dense. f
Total Depth = 2'
No ground water encountered
Backfilled 2-27-98
25-
Lois 1110 CAC GeoSoils, Inc.PLAJE_
BORING LOG
GeoSoils, Inc.
PROJECT.-BWE COMMUNITIES
Lots 1&1OCAC
-Depth (4-
6-
-
10-
~
"
15-
-
20-
Sample i
3
ID Undle-turbvd|
4- i
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V/.O. 24O7-A-SC
BORING B-2 SHEET 1 OF 1
DATE EXCAYATSD 2-27-98
^ ', SAMPLE METHOD: Hand Auger
! s :£
o
j Standard Penetration Test
>
+• '• rr--, ^ Water Seepage into hole? i yM Undisturbed, Ring Sample
3 •
•i- ' ' "~~ ~• Description of Material
:..-*• •
\
i
j
j
i
t
DELMAR FORMATION
@ 0', SILTY SANDSTONE TO SANDY SILTSTONE, olive
gray, wet, loose/soft; very fine to fine.
V@ 1 ', grades to moist, dense/stiff. f
Total Depth = 2'
No ground water encountered
Backfilled 2-27-98
-
25-
Lois 1&10 CAC GeoSoils, Inc.PLATE
BORING LOG
GeoSoils, Inc.
W.O. 24O7-A-SC
/WOL/ECTrBUIE COMMUNITIES BORING B-3 SW££7 1 Of 1
Lots 1 &1 0 CAC
DATE EXCA VA TED 2-27-98
SamDfo !
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SAMPLE METHOD: Hand Auger
S^l Stamford Penetration Test
—.j.
mi.
P— - % Wafer Seepage into hole
Y7/A UncBsturted, Ring Sample
3••*-
00 Description of Material
I
I
'
i
DELMAR FORMATION
@ 0', SANDY SILTSTONE, brownish gray, wet, soft to
medium stiff.
\@ 1 ". grades to stiff. [
Total! Depth = 2'
No groundwater encountered
Backfilled 2-27-98
-
2 =
Lats l&'O CAC GeoSoils, Inc.PLA TE B-3
GeoSoils, Inc.
PROJECT:BU\E COMMUNITIES
Lots1&10CAC
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5-
10-
15-
20-
25-
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W. O. 2407-A-SC
BORING B-4 SHEET 1 OF 1
DA TE EXCA VA TED 2-27-98
SAMPLE METHOD: Hand Auger
S&
^_
Standard Penetration Test
^
Undisturbed, Ring Sample
Description of Material
-x^
DELMAR FORMATION
@ 0', SILTY SANDSTONE, olive gray, wet, loose; very fine to
fine.
\@ 1', grades to moist, dense. f
Total Depth = 2'
No groundwater encountered
Backfilled 2-27-98
LO,SI&IOCAC GeoSoils, Inc. pLATE B.4
GeoSoils, Inc.
PROJECT: BUIE COMMUNITIES
Lotsl&IOCAC
Dnpth Cft.)i i i5-
10-
15-
20-
-
Sample
it
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1
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BORING LOG
W.OL 2407-A-SC
flOfl//VG B-5 SWEET 1 Of 1
£MTF EXCA VA TED 2-27-98
SAMPLE METHOD: Hand Auger
1
I^L
Standard Penetration Test
3
; Undisturbed, Ring Sample
Description of Material
ARTIFICIAL niL
@ O', SANDY SILT, brownish gray to olive gray mottied, wet,
loose.
@ 1 ', grades to moist, medium stiff.
@ 2', grades to stiff.
Total Depth = 4'
No groundwater encountered
Backfilled 2-27-98
25-
CAC GeoSoils, Inc.PLATE B-5
BORING LOG
GeoSoils, Inc.
PROJECT: BUIE COMMUNITIES
Lotsl&TCDCAC
w.o.24O7-A-SC
BORING B-6
DATE EXCAVATED 2-27-98
.c•t-o.•a
Sample
*r
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I T3i• 01- Jli
TJ LiC 3 OE:
SAMPLE METHOD: Hand Auger
Standard Penetration Test
Undisturbed, Kng Sample
f\-. Water Seepage into hate
Description of Material
1
25-
DELMAR FORMATION
@ 0', SILTY SANDSTONE, olive gray, wet, loose; very fine to
fine.
\@ V, grades to moist, dense. f
Total Depth = 2'
No ground water encountered
Backfilled 2-27-98
Lots Ti&IOCAC GeoSoils, Inc.PLA TE
GeoSoils, Inc.
fflfO/£C7;8UIE COMMUNITIES
Lots 1&10CAC
4-
1-
£4-
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-
5-
10-
15-
20-
25-
Sample
to Undis-tupbedBlous/ft.usesSumbo i3
4-
L
D stupe (X)o Saturation (JOBORING LOG
W.O. 2407- A-SC
BORING B-7 SHEET 1 OF 1
DA TE EXCA VA TED 2-27-98
SAMPLE METHOD: Hand Auger
I
m
Standard Penetration Test
J
., ^ Water Seepage into hole\ Undisturbed, Ring Sample
Description of Material
:£:DELMAR FORMATION
@ 0', SILTY SANDSTONE, olive gray, wet, loose; fine to
medium.
\@ V, grades to moist, dense. f
Total Depth = 2'
No groundwater encountered
Backfilled 2-27-98
Lotsi&iocAc GeoSoils, Inc. B7
BORING LOG
GeoSoils, Inc.
PROJ€CT:B(JIB COMMUNfTIES
Lots1&10CAC
«»-
+•O.
a
Sample
s
-
5-
10-
;
15-
20-Und!.-turbndBlous/f t ,usesSumbo ISM
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or:Saturation (X)W.O. 2407-A-SC
BORING ' B-8 SHEET 1 OF 1
DATE EXCA VA TED 2-27-98
SAMPLE METHOD: Hand Auger
Ij S&ndard Penetration Test
t
^ Water See&age into hole
1 Undisturbed, Ring Sample
Description of Material
DELMAR FORMATION
@ 0', SILTY SANDSTONE, olive gray, wet, loose; fine to
medium.
\@ 1 ', grades to moist, dense. f~
Total Depth = 2'
No groundwater encountered
BackfiBed 2-27-98
25-
Lc:s 1&10CAC GeoSoils, Inc.PLATE B-8
APPENDIX C
LABORATORY TEST RESULTS
•
1
Res
No.
1
2
3
100
80
SOc
-^a>
20
0
8C
slstarsee R-
Coapact,
Pressure
psi
150
3OO
3OO
R-YALUE TEST REPORT
-
j
™
-
-
-
•
-
*"
Tilt
• :
\ :.
:^s^
•
j
"^
^
tin i • » il 1 1 i t li 1 1 1 1 1 ti tl tml
^
:
:
;
I
•
I
;
i
r^^*^
1 T 1 1 1 t 1 1 R 1 1 1 1 t
•^
1 Mil
">*«^
1 ttllll M '1 1 J !
X) 700 600 5OO 40O 3OO 200
Exudation Pressure - psi
-Value and Expansion pressure - Cal Test 3O1
Density
pcf
101.3
106.2
130.9
ExpansionMoist.PressureXpsi
21.8 1.27
15. B 0.30
10. S 1.39
TEST RESULTS
Horizontal
Press, psi
@ 16O pst
140
118
BO
Height
in.
2.49
2.83
2.71
Exud,
Pressure
psi
169
292
595
100
R !
R ?value-Value _Cnrr-
7 7
13 15
31 35
MATERIAL OESCRIPTIQH
R-Value e 30O psi exudation pressure = 15
Prefect No.: 2818O^.6O
Project! GEO SOILS CARLSBAD
Location: B-* e 0-2FT
WO* 2-JO7
Date: 3— OS-1998
R-VALUE TEST REPORT
GEorawocAL c EKYOTDM^HTAL ENBI*EEH3. INC.
•
:
LISHTT YELLOWIS BROWN
CLAYEY SILTY SANO
1
Tested by: D. FOSTER
Cnecfced Dy: C. STORTE
R-taar-ks: '
Fig. ND.
Plate C-1
M. J. Schiff & Associates, Inc.
Consulting Corrosion Engineers ~ Since 1959 1291 N. Indian Hill Boulevard
Claremont, CA 91711-3897
Phone 909.626.0967
Table 1 - Laboratory Tests on Sofl Samples
Lot 1&10
Tour 32407-A-SC, MJS&A #98091
3-Feb-98
Sample ID B-4
Soil Type -
Resistivity
as-received
saturated
pH
Electrical
Conductivity
Chemical Analyses
Cations
calcium
Units
ohmt-cm
ohm-cm
inScm
Ca-
magnesium Mg"
Xa
clay
250
205
52
2.42
1,130
389
1,182
ND
ND
2377
3.224
na
na
ru
na
Electrical conductivity in milliiiernens cm and chemical analysis were made on a 1:5 soil-to-waier extract,
mg kg = milligrams per ScSognm fpars per miilioo) of dr>' soil.
Redox = oxidarioc-rethictfon potential in millivolts
ND = not detectec
na = not
sodium
Anions
carbonate mglg
bicarbonate HCOj" mg.kg
chloride
sulfate
Other Tests
sulfide
Redox
ammonium
nitrate
cr
S0t^
S:"
NH,1"
NO,1'
•MH^BIB^n
matg
mzig
quaj
inv
mg. Vg
agjg
2* 1 of 1
Plate C-2
APPENDIX D
GRADING GUIDELINES
GENERAL EARTHWORK AND GRADING GUIDELINES
General
These guidelines present general procedures and requirements for earthwork and grading
as shown on the approved grading plans, including preparation of areas to filled,
placement of fill, installation of subdrains and excavations. The recommendations
contained in the geotechnical report are part of the earthwork and grading guidelines and
would supersede the provisions contained hereafter in the case of conflict. Evaluations
performed by the consultant during the course of grading may result in new
recommendations which could supersede these guidelines or the recommendations
contained in the geotechnicai report
The contractor is responsible for the satisfactory completion of all earthwork in accordance
with provisions of the project plans and specifications. The project soil engineer and
engineering geologist (geotechnical consultant) or their representatives should provide
observation and testing services, and geotechnical consultation during the duration of the
project.
EARTHWORK OBSERVATIONS AND TESTING
Geotechnical Consultant
Prior to the commencement of grading, a qualified geotechnical consultant (soil engineer
and engineering geologist) should be employed for the purpose of observing earthwork
procedures and testing the fills for conformance with the recommendations of the
geotechnical report, the approved grading plans, and applicable grading codes and
ordinances.
The geotechnical consultant should provide testing and observation so that determination
may be made that the work is being accomplished as specified. It is the responsibility of
the contractor to assist the consultants and keep them apprised of anticipated work
schedules and changes, so that they may schedule their personnel accordingly.
All clean-outs, prepared ground to receive fill, key excavations, and subdrains should be
observed and documented by the project engineering geologist and/or soil engineer prior
to placing and fill. It is the contractors's responsibility to notify the engineering geologist
and soil engineer when such areas are ready for observation.
Laboratory and Field Tests
Maximum dry density tests to determine the degree of compaction should be performed
in accordance with American Standard Testing Materials test method ASTM designation
D-l 557-78. Random field compaction tests should be performed in accordance with test
method ASTM designation D-1556-82, D-2937 or D-2922 and D-3017, at intervals of
approximately 2 feet of fill height or every 100 cubic yards of fill placed. These criteria
GeoSoils, Inc.
would vary depending on the soil conditions and the size of the project. The location and
frequency of testing would be at the discretion of the geotechnical consultant.
Contractor's Responsibility
All clearing, site preparation, and earthwork performed on the project should be conducted
by the contractor, with observation by geotechnical consultants and staged approval by
the governing agencies, as applicable. It is the contractor's responsibility to prepare the
ground surface to receive the fill, to the satisfaction of the soil engineer, and to place,
spread, moisture condition, mix and compact the fill in accordance with the
recommendations of the soil engineer. The contractor should also remove all major non-
earth material considered unsatisfactory by the soil engineer.
It is the sole responsibility of the contractor to provide adequate equipment and methods
to accomplish the earthwork in accordance with applicable grading guidelines, codes or
agency ordinances, and approved grading plans. Sufficient watering apparatus and
compaction equipment should be provided by the contractor with due consideration for
the fill material, rate of placement, and climatic conditions. If, in the opinion of the
geotechnical consultant, unsatisfactory conditions such as questionable weather,
excessive oversized rock, or deleterious material, insufficient support equipment, etc., are
resulting in a quality of work that is not acceptable, the consultant will inform the
contractor, and the contractor is expected to rectify the conditions, and if necessary, stop
work until conditions are satisfactory.
During construction, the contractor shall properly grade all surfaces to maintain good
drainage and prevent ponding of water. The contractor shall take remedial measures to
control surface water and to prevent erosion of graded areas until such time as permanent
drainage and erosion control measures have been installed.
SITE PREPARATION
All major vegetation, including brush, trees, thick grasses, organic debris, and other
deleterious material should be removed and disposed of off-site. These removals must be
concluded prior to placing fill. Existing fill, soil, alluvium, colluvium, or rock materials
determined by the soil engineer or engineering geologist as being unsuitable in-place
should be removed prior to fill placement Depending upon the soil conditions, these
materials may be reused as compacted fills. Any materials incorporated as part of the
compacted fills should be approved by the soil engineer.
Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septic
tanks, wells, pipelines, or other structures not located prior to grading are to be removed
or treated in a manner recommended by the soil engineer. Soft, dry, spongy, highly
fractured, or otherwise unsuitable ground extending to such a depth that surface
processing cannot adequately improve the condition should be over-excavated down to
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GeoSoils, Inc.
firm ground and approved by the soil engineer before compaction and filling operations
continue. Overexcavated ano! processed soils which have been properly mixed and
moisture conditioned should be re-compacted to the minimum relative compaction as
specified in these guidelines.
Existing ground which is determined to be satisfactory for support of the fills should be
scarified to a rrinimum depth of 6 inches or as directed by the soil engineer. After the
scarified ground is brought to optimum moisture consent or greater and mixed, the
materials should be compacted as specified herein. If tthe scarified zone is grater that 6
inches in depth, it may be necessary to rerraove the excess and place the material in lifts
restricted to about 6 inches in compacted tfiickness.
Existing ground wiiich is not satisfactory lo support compacted fill should be over-
excavated as required in the geotechnical report or by tine on-site soils engineer and/or
engineering geologist. Scarification, disc harrowing, or other acceptable form of mixing
should continue until the soils are broken down and free of large lumps or clods, until the
working surface is reasonably uniform and free from ruts, hollow, hummocks, or other
uneven features which would inhibit compaction as described previously.
Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical),
the ground should be stepped or benchedL The lowesit bench, which will act as a key,
should be a minimum of 15 feet wide and shiould be at least 2 feet deep into firm material,
and approved by tine soil engfineer and/or engineering geologist. In fill over col slope
conditions, the recommended minimum width of the lowest bench or key is also 15 feet
with the key founded on firm material, as designated by tine Geotechnical Consultent As
a general rule, urrftess specifically recomnmended otheirwise by the Soil Engineer, the
minimum width of fill keys shoufld be approseimately equal to 1/2 the height of the slope.
Standard benching is generally 4 feet (minimum) vertically, exposing firm, acceptable
material. Benching may be used to remove unsuitable materials, although it is understood
that the vertical height of the bench may exceed 4 feet Pre-stripping may be considered
for unsuitable materials in excess of 4 feet iin thickness.
All areas to receive fill, including processed areas, removal areas, and the toe of fill
benches should be observed and approved by the soil engineer and/or engiineering
geologist prior to pftacement of fill. Fills maylhen be properly placed and compacted until
design grades (elevations) are attained.
COMPACTED FILLS
Any earth materials imported or excavated en the property may be utilized in the fill
prcviced that each materiaJ has been determined to be suitable by the scil engineer.
These materials should be free of roots, tree branches, other organic matter or other
deleterious materials. All unsuitable materials should be removed from the fill as directed
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GeoSoils, Inc.
by the soil engineer. Soils of poor gradation, undesirable expansion potential, or
substandard strength characteristics may be designated by the consultant as unsuitable
and may require blending with other soils to serve as a satisfactory fill material.
Fill materials derived from benching operations should be dispersed throughout the fill
area and blended with other bedrock derived material. Benching operations should not
result in the benched material being placed only within a single equipment width away
from the fill/bedrock contact.
Oversized materials defined as rock or other irreducible materials with a maximum
dimension greater than 12 inches should not be buried or placed in fills unless the location
of materials and disposal methods are specifically approved by the soil engineer.
Oversized material should be taken off-site or placed in accordance with recommendations
of the soil engineer in areas designated as suitable for rock disposal. Oversized material
should not be placed within 10 feet vertically of finish grade (elevation) or within 20 feet
horizontally of slope faces.
To facilitate future trenching, rock should not be placed within the range of foundation
excavations, future utilities, or underground construction unless specifically approved by
the soil engineer and/or the developers representative.
If import material is required for grading, representative samples of the materials to be
utilized as compacted fill should be analyzed in the laboratory by the soil engineer to
determine its physical properties. If any material other than that previously tested is
encountered during grading, an appropriate analysis of this material should be conducted
by the soil engineer as soon as possible.
Approved fill material should be placed in areas prepared to receive fill in near horizontal
layers that when compacted should not exceed 6 inches in thickness. The soil engineer
may approve thick lifts if testing indicates the grading procedures are such that adequate
compaction is being achieved with lifts of greater thickness. Each layer should be spread
evenly and blended to attain uniformity of material and moisture suitable for compaction.
Fill layers at a moisture content less than optimum should be watered and mixed, and wet
fill layers should be aerated by scarification or should be blended with drier material.
Moisture condition, blending, and mixing of the fill layer should continue until the fill
materials have a uniform moisture content at or above optimum moisture.
After each layer has been evenly spread, moisture conditioned and mixed, it should be
uniformly compacted to a minimum of 90 percent of maximum density as determined by
ASTM test designation, D-1557-78, or as otherwise recommended by the soil engineer.
Compaction equipment should be adequately sized and should be specifically designed
for soil compaction or of proven reliability to efficiently achieve the specified degree of
compaction.
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Where tests indicate that the density of any layer of fill, or portion thereof, is below the
required relative compaction, or improper moisture is in evidence, the particular layer or
portion shall be re-worked until the required density and/or moisture content has been
attained. No additional fill shall be placed in an area until the last placed lift of fill has been
tested and found to meet the density and moisture requirements, and is approved by the
soil engineer.
Compaction of slopes should be accomplished by over-building a minimum of 3 feet
horizontally, and subsequently trimming back to the design slope configuration. Testing
shall be performed as the fill is elevated to evaluate compaction as the fill core is being
developed. Special efforts may be necessary to attain the specified compaction in the fill
slope zone. Final slope shaping should be performed by trimming and removing loose
materials with appropriate equipment A final determination of fill slope compaction should
be based on observation and/or testing of the finished slope face. Where compacted fill
slopes are designed steeper than 2:1 (horizontal to vertical), specific material types, a
higher minimum relative compaction, and special grading procedures, may be
recommended.
If an alternative to over-building and cutting back the compacted fill slopes is selected,
then special effort should be made to achieve the required compaction in the outer 10 feet
of each lift of fill by undertaking the following:
1. An extra piece of equipment consisting of a heavy short shanked sneepsfoot should
be used to roll (horizontal) parallel to the slopes continuously as fill is placed. The
sheepsfoot roller should also be used to roll perpendicular to the slopes, and
extend out over the slope to provide adequate compaction to the face of the slope.
2. Loose fill should not be spilled out over the face of the slope as each lift is
compacted. Any loose fill spilled over a previously completed slope face should be
trimmed off or be subject to re-rolling.
3. Field compaction tests will be made in the outer (horizontal) 2 to 8 feet of the stope
at appropriate vertical intervals, subsequent to compaction operations.
4. After completion of the slope, the slope face should be shaped with a small tractor
and then re-rolled with a sheepsfoot to achieve compaction to near the slope face.
Subsequent to testing to verify compaction, the slopes should be grid-roiled to
achieve compaction to the slope face. Final testing should be used to confirm
compaction after grid rolling.
5. Where testing indicates less than adequate compaction, the contractor will be
responsible to rip, water, mix and re-compact the slope material' as necessary to
achieve compaction. Additional testing should be performed to verify compaction.
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6. Erosion control and drainage devices should be designed by the project civil
engineer in compliance with ordinances of the controlling governmental agencies,
and/or in accordance with the recommendation of the soil engineer or engineering
geologist.
SUBDRAIN INSTALLATION
Subdrains should be installed in approved ground in accordance with the approximate
alignment and details indicated by the geotechnical consultant. Subdrain locations or
materials should not be changed or modified without approval of the geotechnical
consultant. The soil engineer and/or engineering geologist may recommend and direct
changes in subdrain line, grade and drain material in the field, pending exposed
conditions. The location of constructed subdrains should be recorded by the project civil
engineer.
EXCAVATIONS
Excavations and cut slopes should be examined during grading by the engineering
geologist. If directed by the engineering geologist, further excavations or overexcavation
and re-filling of cut areas should be performed and/or remedial grading of cut slopes
should be performed. When fill over cut slopes are to be graded, unless otherwise
approved, the cut portion of the slope should be observed by the engineering geologist
prior to'placement of materials for construction of the fill portion of the slope.
The engineering geologist should observe all cut slopes and should be notified by the
contractor when cut slopes are started.
If, during the course of grading, unforeseen adverse or potential adverse geologic
conditions are encountered, the engineering geologist and soil engineer should
investigate, evaluate and make recommendations to treat these problems. The need for
cut slope buttressing or stabilizing should be based on in-grading evaluation by the
engineering geologist, whether anticipated or not.
Unless otherwise specified in soil and geological reports, no cut slopes should be
excavated higher or steeper than that allowed by the ordinances of controlling
governmental agencies. Additionally, short-term stability of temporary cut slopes is the
contractors responsibility.
Erosion control and drainage devices should be designed by the project civil engineer and
should be constructed in compliance with the ordinances of the controlling governmental
agencies, and/or in accordance with the recommendations of the soil engineer or
engineering geologist.
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COMPLETION
Observation, testing and consultation by the geotechnical consultant should be conducted
during the grading operations in order to state an opinion that all cut and filled areas are
graded in accordance with the approved project specifications.
After completion of grading and after the soil engineer and engineering geologist have
finished their observations of the work, final reports should be submitted subject to review
by the controlling governmental agencies. No further excavation or filling should be
undertaken without prior notification of the soil engineer and/or engineering geologist.
Ai! finished cut and fill slopes should be protected from erosion and/or be planted in
accordance with the project specifications and/or as recommended by a landscape
architect. Such protection and/or planning should be undertaken as soon as practical after
completion of grading.
JOB SAFETY
General
At GeoSoils, Inc. (GSI) getting the job done safely is of primary concern. The following is
the company's safety considerations for use by all employees on mufti-employer
construction sites. On ground personnel are at highest risk of injury and possible fatality
on grading and construction projects. GSI recognizes that construction activities will vary
on each site and that site safety is the prime responsibility of the contractor; however,
everyone must be safety conscious and responsible at all times. To achieve our goal of
avoiding accidents, cooperation between the client, the contractor and GSI personnel must
be maintained.
In an effort to minimize risks associated with geotechnical testing and observation, the
following precautions are to be implemented for the safety of field personnel on grading
and construction projects:
Safety Meetings: GSI field personnel are directed to attend contractors regularly
scheduled and documented safety meetings.
Safety Vests: Safety vests are provided for and are to be worn by GS! personnel at
all times when they are working in the field.
Safety Flags: Two safety flags are provided to GSI field technicians; one is to be
affixed to the vehicle when on site, the other is to be placed atop the
spoil pile on all test pits.
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GeoSoils, Inc.
Flashing Lights: All vehicles stationary in the grading area shall use rotating or flashing
amber beacon, or strobe lights, on the vehicle during all field testing.
While operating a vehicle in the grading area, the emergency flasher
on the vehicle shall be activated.
In the event that the contractor's representative observes any of our personnel not
following the above, we request that it be brought to the attention of our office.
Test Pits Location. Orientation and Clearance
The technician is responsible for selecting test pit locations. A primary concern should be
the technicians's safety. Efforts will be made to coordinate locations with the grading
contractors authorized representative, and to select locations following or behind the
established traffic pattern, preferably outside of current traffic. The contractors authorized
representative (dump man, operator, supervisor, grade checker, etc.) should direct
excavation of the pit and safety during the test period. Of paramount concern should be
the soil technicians safety and obtaining enough tests to represent the fill.
Test pits should be excavated so that the spoil pile is placed away form oncoming traffic,
whenever possible. The technician's vehicle is to be placed next to the test pit, opposite
the spoil pile. This necessitates the fill be maintained in a driveable condition.
Alternatively, the contractor may wish to park a piece of equipment in front of the test
holes, particulariy in small fill areas or those with limited access.
A zone of non-encroachment should be established for all test pits. No grading equipment
should enter this zone during the testing procedure. The zone should extend
approximately 50 feet outward from the center of the test pit. This zone is established for
safety and to avoid excessive ground vibration which typically decreased test results.
When taking slope tests the technician should park the vehicle directly above or below the
test location. If this is not possible, a prominent flag should be placed at the top of the
slope. The contractor's representative should effectively keep all equipment at a safe
operation distance (e.g. 50 feet) away from the slope during this testing.
The technician is directed to withdraw from the active portion of the fill as soon as possible
following testing. The technician's vehicle should be parked at the perimeter of the fill in
a highly visible location, well away from the equipment traffic pattern.
The contractor should inform our personneJ of all changes to haul reads, cut and fill areas
or other factors that may affect site access and site safety.
in the event that the technicians safety is jeopardized or compromised as a result of the
contractors failure to comply with any of the above, the technician is required, by company
policy, to immediateiy withdraw and notify his/her supervisor. The grading contractors
representative wili eventually be contacted in an effort to effect a solution. However, in the
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interim, no further testing will be performed until the situation is rectified. Any fill place can
be considered unacceptable and subject to reprocessing, recompaction or removal.
In the event that the soil technician does not comply with the above or other established
safely guidelines, we request that the contractor brings this to his/her attention and notify
this office. Effective communication and coordination between the contractors
representative and the soils technician is strongly encouraged in order to implement the
above safety plan.
Trench and Vertical Excavation
It is the contractor's responsibility to provide safe access into trenches where compaction
testing is needed.
Our personnel are directed not to enter any excavation or vertical cut which 1) is 5 feet or
deeper unless shored or laid back, 2) displays any evidence of instability, has any loose
rock or other debris which could fall into the trench, or 3) displays any other evidence of
any unsafe conditions regardless of depth.
All trench excavations or vertical cuts in excess of 5 feet deep, which any person enters,
should be shored or laid back.
Trench access should be provided in accordance with CAL-OSHA and/or state and local
standards. Our personnel are directed not to enter any trench by being lowered or "riding
down" on the equipment.
If the contractor fails to provide safe access to trenches for compaction testing, our
company policy requires that the soil technician withdraw and notify his/her supervisor.
The contractors representative will eventually be contacted in an effort to effect a solution.
All backfill not tested due to safety concerns or other reasons could be subject to
reprocessing and/or removal.
If GSI personnel become aware of anyone working beneath an unsafe trench wall or
vertical excavation, we have a legal obligation to put the contractor and owner/developer
on notice to immediately correct the situation. If corrective steps are not taken, GSI then
has an obligation to notify CAL-OSHA and/or the proper authorities.
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FILL OVER NATURAL DETAIL
SIDEHILL FILL
PROPOSED GRADE
TOE OF SLOPE AS SHOWN ON GRADING PLAN
PROVIDE A 1:1 MINIMUM PROJECTION FROM
DESIGN TOE OF SLOPE TO TOE OF KEY
AS SHOWN ON AS BUILT
FFl
mo
I
CD
COMPACTED FILL
MAINTAIN MINIMUM 15* WIDTH
SLOPE TO BENCH/BACKCUT
NATURAL SLOPE TO
BE RESTORED WITH
COMPACTED FILL
DACKCUT VARIES
'MINIMUM
15'MINIMUM KEY WIDT
2'X 31 MINIMUM KEY DEPTH
2'M)NIMUM IN BEDROCK OR
APPROVED MATERIAL.
WIDTH MAY VARY• • - » ^ « ••( -
""Jr. MINIMUM
NOTE; 1. WHERE THE NATURAL SLOPE APPROACHES OR EXCEEDS THE
DESIGN SLOPE RATKX SPECIAL RECOMMENDATIONS WOULD BE
PROVIDED BY THE SOILS ENGINEER.
2. THE NEED FOR AND DISPOSITION OF DRAINS WOULD BE DETERMINED
BY THE SOILS ENGINEER BASED UPON EXPOSED CONDITIONS.
FILL OVER CUT DETAIL
CUT/FILL CONTACT.
1. AS SHOWN ON GRADING PLAN
2. AS SHOWN ON AS BUILT
MAINTAIN MINIMUM 15'FILL SECTION FROM
BACKCUT TO FACE OF FINISH SLOPE
PROPOSED GRADE
ORIGINAL TOPOGRAPHY
CK OR APPROVED MATERIAL
ILOWEST BENCH WIDTH
15'MINIMUM OR H/2
BENCH WIDTH MAY VARY
"D
m
mo
NOTE: THE CUT PORTION OF THE SLOPE SHOULD BE EXCAVATED AND
EVALUATED BY THE SOILS ENGINEER AND/OR ENGINEERING
GEOLOGIST PRIOR TO CONSTRUCTING THE FILL PORTION.
SKIN FILL OF NATURAL GROUND
ORIGINAL SLOPE
'ROPOSED FINISH GRADE
m
mo
15* MINIMUM TO BE MAINTAINED FROM
PROPOSED FINISH SLOPE FACE TO BACKCUT
PROPOSED FINISH SLOPE BEDROCK OR APPROVED MATERIAL
NIMUM KEY WIDTH
MINIMUM KEY DEPTH
NOTE: 1. THE NEED AND DISPOSITION OF DRAINS WILL BE DETERMINED! BY THE SOILS ENGINEER AND/OR
ENGINEERING GEOLOGIST BASED ON FIELD CONDITIONS.
2. PAD OVEREXCAVATION AND RECOMPACTION SHOULD BE PERFORMED IF DETERMINED TO BE
NECESSARY BY THE SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST.
DAYLIGHT CUT LOT DETAIL
RECONSTRUCT COMPACTED FILL SLOPE AT 2:1 OR FLATTER
(MAY INCREASE OR DECREASE PAD AREA).
OVEREXCAVATE AND RECOMPACT
REPLACEMENT FILL
NATURAL GRADE
PROPOSED FINISH GRADE
AVOID AND/OR CLEAN UP SPILLAGE OF 3* MINIMUM BLANKET FILL
MATERIALS ON THE NATURAL SLOPE
/^.
TYPICAL BENCHING
MINIMUM
DEPTH
W5' BEDROCK OR APPROVED MATERIAL
TJ
Hm
mo
NOTE: 1. SUBDRAIN AND KEY WIDTH REQUIREMENTS WILL BE DETERMINED BASED ON EXPOSED SUBSURFACE
CONDITIONS AND THICKNESS OF OVERBURDEN.
2. PAD OVER EXCAVATION AND RECOMPACTION SHOULD BE PERFORMED IF DETERMINED NECESSARY BY
THE SOILS ENGINEER AND/OR THE ENGINEERING GEOLOGIST.
O
TRANSITION LOT DETAIL
CUT LOT (MATERIAL TYPE TRANSITION)
NATURAL GRADE
OVEREXCAVATE AND RECOMPACT
\\\^A\W\\\# 3'MINIMUM*
^ UNWEATHERED BEDROCK OR APPROVED MATERIAL
TYPICAL BENCHING
CUT-FILL LOT (DAYLIGHT TRANSITION)
NATURAL GRADE <<^
OVEREXCAVATE
AND RECOMPACT
r MINIMUM*
UNWEATHESED BEDROCK OR APPROVED MATERIAL
TYPICAL BENCHING
NOTE' «OE ==E.R OVEREXCAVATION MAY BE RECOMMENDED BY THE SOILS ENGINEER
AND/OR ENGINEERING GEOLOGIST IN STE=? CUT-FiLL TRANS.T.CN AREAS.
PLATE EG-11
TEST PIT SAFETY DIAGRAM
SIDE VIEW
| NOT TO SCALE J
APPROXIMATE C2TTEK
OF TE37PIT
FUkG
NOT TO SCALE J
PLATE EG—16
APPENDIX E
PAVEMENT GRADING GUIDELINES
APPENDIX E
Pavement Grading Recommendations
General
All section changes should be properly transitioned. If adverse conditions are encountered
during the preparation of subgrade materiaJs, special construction methods may need to
be employed.
Suborade
Within street and parking areas, ail surficiai deposits of loose soil material should be
removed and recompacted as recommended. After the loose soils are removed, the
bottom is to be scarified to a depth of 6 inches, moisture conditioned as necessary and
compacted to 95 percent of maximum laboratory density, as determined by ASTM test
designation D-1557.
Deleterious material, excessively wet or dry pockets, concentrated zones of oversized rock
fragments, and any other unsuitable materials encountered during grading should be
removed.
The compacted fill material should then be brought to the elevation of the proposed
subgrade for the pavement. The subgrade should be proof-rolled in order to ensure a
uniformly firm and unyielding surface.
All grading and fill placement should be observed by the project soil engineer and/or his
representative.
Base/Subbase
Compaction tests are required for the recommended base/subbase section. Minimum
relative compaction required will be 95 percent of the maximum laboratory density as
determined by ASTM Test Designation D-1557. Base/subbase aggregate should be in
accordance to the "Standard Specifications for Public Works Construction" (green book)
current edition.
Paving
Prime coat may be omitted if all of the following conditions are met:
1. The asphart pavement layer is placed within two weeks of completion of base and/or
subbase course.
2. Traffic is not routed over completed base before paving.
GeoSoils, Inc.
3. Construction is completed during the dry season of May through October.
4. The base is free of dirt and debris.
If construction is performed during the wet season of November through April, prime coat
may be omitted if no rain occurs between completion of base course and paving and the
time between completion of base and paving is reduced to three days, provided the base
is free of dirt and debris. Where prime coat has been omitted and rain occurs, traffic is
routed over base course, or paving is delayed, measures shall be taken to restore base
course, subbase course, and subgrade to conditions that will meet specifications as
directed by the soil engineer.
Drainage
Positive drainage should be provided for all surface water to drain towards the area swale,
curb and gutter, or to an approved drainage channel. Positive site drainage should be
maintained at ail times. Water should not be allowed to pond or seep into the ground. If
planters or landscaping are adjacent to paved areas, measures should be taken to
minimize the potential for water to enter the pavement section.
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