HomeMy WebLinkAboutCT 05-10; POINSETTIA PROPERTIES THE TIDES; PRELIMINARY GEOTECHNICAL INVESTIGATION REPORT; 2005-02-25,I
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Lawson & Associates Geotechnical Consulting, Inc.
Preliminary Geotechnical Investigation Report,
Proposed 29-Lot Residential Development,
Southwest Corner of Poinsettia Lane and
Paseo Del Norte, City of Carlsbad,
California
Dated: February 25, 2005
Project No. 041065-02
Prepared For:
COTTAGE DEVELOPMENT COMPANY
209 A venida Del Mar, Suite 204
San Clemente, CA 92672
1319 Calle Avanzado • San Clemente· CA 92673-6351 ·949.369.6141 • Fax: 949.369.6142· www.lgcgeo.com
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Lawson & Associates Geotechnical Consulting, Inc.
February 25, 2005
Mr. David Gutierrez
Cottage Development Company
209 A venida Del Mar, Suite 204
San Clemente, CA 92672
Project No. 041065-02
Subject: Preliminary Geotechnical Investigation Report, Proposed 29·Lot Residential
Development, Southwest Corner of Poinsettia Lane and Paseo Del Norte, City of
Carlsbad, California
In accordance with your request, Lawson & Associates Geotechnical Consulting, Inc. (LGC) has
performed a preliminary geotechnical investigation for the proposed 29-10t residential development
located at the southwest corner of Poinsettia Lane and Paseo Del Norte in the city of Carlsbad,
California. The purpose of our investigation was to evaluate the existing onsite geotechnicru conditions and
review the readily available geotechnical and geologic reports and maps pertinent to the site. This report
presents the results of our subsurface investigation and geotechnical analysis and provides a summary of
our conclusions and preliminary recommendations relative to the proposed development"of the site.
If you should have any questions regarding this report, please do not hesitate to contact our office. We
appreciate this opportunity to be of service.
Sincerely,
LA WSON & ASSOCIATES GEOTECHNICAL CONSULTING, INC.
//~ 8.U--
Kevin B. Colson, CEG 2210
Associate Geologist
!I~/~
Brad Zellmer, GE 2618
Associate Engineer
BTZJKBCIP AS/sec
Distribution: (5) Addressee
1319 Calle Avanzado • San Clemente· CA 92673-6351 ·949.369.6141 • Fax: 949.369.6142 • www.lgcgeo.com
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TA BLE OF CONTENTS
Section Eage
1.0 INTRODUCTION ..................................................................................................................... 1
1.1 Purpose and Scope of Services ...................................................................................... 1
1.2 Project Description and Background ................................... : .......................................... 1
1.3 Subsurface Investigation ................................................................................................ 2
1.4 Laboratory Testing ......................................................................................................... 2
2.0 GEOTECHNICAL CONDITIONS ............................................................................................ 5
2.1 Regional Geology .......................................................................................................... 5
2.2 Site-Specific Geology .................................................................................................... 5
2.2.1 Artificial Fill-Undocumented (Map Symbol-Afu) ....................................... 5
2.2.2 Terrace Deposits (Map Symbol-Qt) ................................................................ 5
2.3 Geologic Structure ......................................................................................................... 6
2.4 Landslides ...................................................................................................................... 6
2.5 Ground Water ................................................................................................................ 6
2.6 Faulting .......................................................................................................................... 6
2.6.1 Lurching and Shallow Ground Rupture ............................................................ 7
2.6.2 Liquefaction and Dynamic Settlement ..................................................... , ....... 7
2.6.3 Tsunamis and Seiches ....................................................................................... 8
2.7 Seismicity ...................................................................................................................... 8
2.8 Slopes ............................................................................................................................ 8
2.9 Rippability ..................................................................................................................... 8
2.10 Oversized Material ........................................................................................................ 9
2.11 Expansive Soil Characteristics ...................................................................................... 9
2.12 Corrosion Potential ....................................................................................................... 9
3.0 CONCLUSIONS ..................................................................................................................... 10
4.0 RECOMMENDATIONS ........................................................................................................ 11
4.1 Site Earthwork ............................................................................................................. 11
4.1.1 Site Preparation ............................................................................................... 11
4.1.2 Removal and Recompaction ............................................................................ 11
4.1.3 Temporary Stability of Removal Excavations .................................................. 12
4.1.4 Fill Placement and Compaction ....................................................................... 12
4.1.5 Placement of Expansive Soils .......................................................................... 12
4.1.6 Fill Settlement ................................................................................................. 13
4.1.7 Shrinkage and Bulking ..................................................................................... 13
4.1.8 Trench Backfill and Compaction ..................................................................... 13
4.2 Slope Stability ............................................................................................................. 13
4.2.1 Cut Slopes .........................................•............................................................. 13
4.2.2 Fill Slopes .............................................. ; .. , .•............................................... ' .... 13
4.3 Seismic Design Criteria .............................................................................................. 14
4.4 Soil Bearing ................................................................................................................ 14
4.5 Provisional Foundation Recommendations ................................................................ 15
4.5.1 Conventional Slab on Ground Foundations .................................................... 15
Project No. 041065-02 Pagei February 25,2005
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TARLE OF CONTENTS (Cont'd)
4.5.2 Post-Tension Foundation Design Parameters ................................................. 15
4.5.3 Foundation Subgrade Preparation and Maintenance ...................................... 16
4.5.4 Vapor Retarded and Sand Below Slabs ......................................... i ................ 16
4.6 Lateral Earth Pressures and Retaining Wall Design Considerations ............................. 18
4.7 Retaining Walls at the Top of Slopes ......................................................................... 20
4.8 Proposed Tiered Retaining Wall System .................................................................... 20
4.9 Preliminary Pavement Sections .................................................................................... 22
4.10 Corrosivity to Concrete and Metal ............................................................................... 22
4.11 Nonstructural Concrete Flatwork ................................................................................ 22
4.12 Control of Surface Water and Drainage Control .......................................................... 23
4.13 Freestanding Walls ...................................................................................................... 24
4.14 Review of Project Plans .............................................................................................. 24
4.15 Construction Observation and Testing ......................................................................... 24
5.0 LIMITATIONS ....................................................................................................................... 25
List of Illustrations. Tables.. and A nnendices • ~z
Figures
Figure 1 -Site Location Map (page 4)
Figure 2 -Geotechnical Map (Rear of Text)
Figure 3 -Retaining Wall Drainage Detail (page 21)
Tables
Table 1 -Preliminary Geotechnical Parameters for Post-Tensioned Foundation Design for Low
Expansion Potential (page 18)
Table 2 -Lateral Earth Pressures (Page 19)
Table 3 -Nonstructural Concrete Flatwork for Low Expansion Potential (page 23)
Appendices
Appendix A -References
Appendix B -Boring Logs
Appendix C -Laboratory Test Results
Appendix D -Seismic Analyses
Appendix E -General Earthwork and Grading Specifications for Rough Grading
Project No. 041065-02 Page ii February 25,2005
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1.1
1.2
1.0 TNTRODUCT10N
Purpose and Scope of Services
This report presents the results of our preliminary geotechnical investigation for the proposed
29-lot residential development located at the southwest corner of Poinsettia Lane and Paseo
Del Norte in the city of Carlsbad, California (see Site Location Map, Figure 1). The purpose of
our investigation was to evaluate the pertinent geotechnical conditions at the site and to provide
design criteria relative to the proposed development of the site. The conceptual plan provided
by Rick Engineering Company (Rick, 2005) has been utilized as a base map for analysis and
presentation of the data obtained in this study (see Figure 2).
Our scope of services included:
• Review of pertinent readily available geotechnical reports and geologic maps
(Appendix A);
• Reconnaissance level geologic mapping of the site;
• Excavation, sampling, and logging of five small-diameter hollow stem auger borings
(LGC-l through LGC-5). The excavations were sampled and logged under the supervision
of an experienced geologist from our firm. The borings were excavated to evaluate the
general characteristics of the subsurface geologic conditions including depth of fill,
estimated depth to ground water (if any), and to obtain representative soil samples. Logs of
the borings are presented in Appendix B and their approximate locations are depicted on
the Geotechnical Map, Figure 2;
• Laboratory testing of representative samples obtained during our subsurface investigation
(Appendix C);
• Preparation of a geotechnical map depicting the interpreted geologic conditions on the site;
• Preparation of a geotechnical cross-section depicting the interpreted geotechnical
conditions below the site;
• Performed slope stability analysis on the prepared cross-section;
• Geotechnical analysis of the data reviewed/obtained;
• Preparation of this report presenting our findings, conclusions and preliminary
recommendations with respect to the proposed site development.
Prqject Description and Background
The site is a rectangular-shaped property, located southwest of the intersection of Poinsettia
Lane and Paseo Del Norte in the city of Carlsbad, California. Grading operations are
anticipated to include site grading for construction of associated streets, underground utilities
and the 29 proposed residential structures. Based on the conceptual development plan,
retaining walls are proposed around the majority of the perimeter of the site, includimrti-etecl::J
retaining walls in the southern portion adjacent to the freeway off-ramp. A grading plan was
not available at the date of this report.
Project No. 041065-02 Pagel February 25,2005
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Topographically, the site consists of two graded pads, which dip gently from the east to the
west. On the north, south, and west sides of the site, approximately 2: 1 (horizontal to
vertical) slopes descend from the site. The site has a total elevation drop of approximately
18-to-20 feet to the west. An approximately 5-to-6-foot high slope separates the eastern and
western pads.
1.3 SuhSll1j'ace Tuyestigatiou
Our subsurface investigation consisted of the excavation of five small-diameter borings,
ranging in depth from approximately 15 to approximately 29 feet below existing ground
surface. During excavation, the borings were sampled and logged from the surface under the
supervision of an experienced geologist from our firm to evaluate the general characteristics of
the onsite soils. The hollow stem borings were geotechnically logged and sampled using
California Ring Samples (Ring) and Standard Penetration Test (SPT) samplers at selected
intervals. The SPT and ring samples were driven using a 140-pound hammer freely falling for
30 inches with a total penetration of 18 inches. The number of blows required to drive the
sampler were recorded at 6-inch intervals for further analysis. In addition, bulk samples of
varying material types were collected from the borings.
Soil descriptions are presented in the boring logs included in Appendix B. The approximate
locations of the borings are shown on our Geotechnical Map, Figure 2. The excavations for this
investigation were backfilled with bentonite chips. Please note that some settlement of the
backfill for the borings may occur over time and they should be topped off if needed.
1.4 Lahorator)! Testing
Representative bulk and driven (relatively undisturbed) samples were retained for laboratory
testing. Laboratory testing included in-situ moisture content and in-situ density, maximum dry
density and optimum moisture content (laboratory compaction), grain size distribution,
consolidation, direct shear, and corrosivity (sulfate, chloride, pH and resistivity).
Dry density values ranged from approximately 110.1 pounds per cubic foot (pet) to 131.5
pcf, with an average of 117.9 pcf. Field moisture contents ranged from approximately 4.0
percent to 9.1 percent, with an average of 6.1 percent. Total (moist) density values ranged
from approximately 116.3 pcf to 138.9 pcf, with an average of 125.1 pcf. The degree of
saturation ranged from approximately 25 percent to 54 percent, with an average of 39
percent.
Two laboratory maximum dry density (compaction) tests were performed from bulk samples
obtained from boring LGC-l and LGC-5.
Two sieve and hydrometer analyses were performed on samples from borings LGC-2 and
LGC-3 (12.5 and 10 feet deep, respectively). Results indicate the samples contain
approximately 23 to 29 percent fines (passing the No. 200 sieve) and are classified as
"coarse-grained" according to the Unified Soils Classification System (USCS).
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Four consolidation tests were performed on samples ranging from approximately 10 to 15 feet
below existing grade. Collapse at water inundation was up to approximately four percent.
A direct shear test was performed from a sample obtained from Boring LGC-2. The peak
shear strength parameters resulted in an approximate friction angle of 30.8 degrees and a
cohesion of 215 pounds per square foot (psf). The ultimate shear strength parameters
(deformation at 1,4 of an inch) resulted in an approximate friction angle of 32.1 degrees and
cohesion of 60 psf.
A discussion of the laboratory tests performed and a summary of the results are presented in
Appendix C. The moisture and density test results are presented on the trench and boring logs
in Appendix B. Results of corrosion suite are reported in Section 2.12.
Project No. 041065-02 Page 3 February 25,2005
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I LGC FIGURE 1
Site Location Map
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2.1
2.2
2.0 GlWTECHNTCA" CONDWONS
Regional Geolag)!
Regionally, the site is located within the coastal sub-province of the Peninsular Ranges
Geomorphic Province, near the western edge of the Southern California batholith. The
topography at the edge of the batholith changes from the rugged landforms developed on the
batholith to the more subdued landforms, which typify the softer sedimentary formations of the
coastal plain. Tertiary and Quaternary rocks are generally comprised of marine and non-marine
sediments consisting of sandstone, mudstones, conglomerates, and occasional volcanic units.
Erosion and regional tectonic uplift created the valleys and ridges of the area.
Site-Specific GeOlagJ
The primary units encountered in our subsurface investigatrQ![j[lc1ude'd-undocum?nteaJ511)
\:0verlying-~uatemaFy~'Ferrace-mqteria~. A brief description of these geologic units is
presented below ~ITom youngest to oldest).
2.2.1 Artificial Fill-undocumented (Map Symbol-Afu,>
Approximately, ~e-lSntir~-site_consists_oLartificiaL:fiILmateriaLplaced_ab011t-20-plus~
Years;.ago..Jri..UIQuLddcumentatLoJi.:..oLc_ompaction-:The11U-nrateda:l-wffs-fo1iiiOTo extend
fap.pLoximateIy 20:feerb-e-rre-ath-:tye existing surface during our investigation. The
undocumented artificial fill was also encountered on the site during an investigation in
1981 by Medall, Aragon, Worswick & Associates, Inc. (Medall, 1981). In general, the
fill materials encountered during our investigation consisted o:Cflrre-to""~1ijTIffi-$iltv
~~ith minor amounts of gravel at depth. The fill was light brown to reddish brown,
generally loose to medium dense and slightly moist.
Based on laboratory consolidation testing of onsite undocumented fill soils, collapse at
water inundation was up to approximately 4 percent. Therefore, e~g unQ6cuUienteW
~~Y7c~nsiae~u~ceptib:le:1CJcull~J2-str1IfiO$nom(rl5.e removeaandrecomp..ac~cb
for future development.
2.2.2 Terrace Deposits (Map Symbol-at)
Quaternary-aged terrace deposits were encountered beneath the artificial fill across the
site. The terrace deposit generally consisted of light brown to red brown, damp to
moist, dense sand and very dense sand. Borings LGC-l, LGC-3 and LGC-4 met
refusal at depths of 27.5, 21.5 and 23 feet below the surface, respectively.
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2.3
2.4
2.5
2.6
Geolagic Structure
Based on our limited subsurface investigation, literature review and our professional experience
on nearby sites, the buried terrace deposits are generally massive to indistinctly bedded. No
faults have been mapped on the site nor were any encountered during our field study.
Landslides
No landslides have been identified on the site.
Ground Water
tG:t:otH1d-water-was-n0t-~nGOunter-€d-dhring our investigation to the total depth investigated, up
to approximatelyt2§)~~r-belOVl""'eg:isting ground surface. In general, ground water is not
expected to be a major problem on the site. If ground water seepage is encountered mitigation
recommendations can be provided to reduce the impact of ground water seepage or saturated
conditions.
Faultjng
California is located on the boundary between the Pacific and North American Lithospheric
Plates. The average motion along this boundary is on the order of 50-rnmIyr in a right-lateral
sense. The majority of the motion is expressed at the surface along the northwest trending San
Andreas Fault Zone with lesser amounts of motion accommodated by subparallel faults located
predominantly west of the San Andreas including the Elsinore, Newport-Inglewood, Rose
Canyon, and Coronado Bank Faults. Within Southern California, a large bend in the San
Andreas Fault north of the San Gabriel Mountains has resulted in a transfer of a portion of the
right-lateral motion between the plates into left-lateral displacement and vertical uplift.
Compression south and west of the bend has resulted in folding, left-lateral, reverse, thrust
faulting, and regional uplift creating the east-west trending Transverse Ranges and several east-
west trending faults. Further south within the Los Angeles Basin, "blind thrust" faults are
believed to have developed below the surface also as a result of this compression, which have
resulted in earthquakes such as the 1994 Northridge event along faults with little to no surface
expression.
Prompted by damaging earthquakes in Northern and Southern California, State legislation and
policies concerning the classification and land-use criteria associated with faults have been
developed. Their purpose was to prevent the construction of urban developments across the
trace of active faults. The result is the Alquist-Priolo Earthquake Fault Zoning Act, which was
most recently revised in 1997 (Hart, 1997). According to the State Geologist, an active fault is
defined as one that has had surface displacement within the Holocene Epoch (roughly the last
11,000 years). A potentially active fault is defined as any fault, which has had surface
displacement during Quaternary time (last 1,600,000 years), but not within the Holocene.
Earthquake Fault Zones have been delineated along the traces of active faults within California.
Project No. 041065-02 Page 6 February 25,2005
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Where developments for human occupation are proposed within these zones, the state requires
detailed fault investigations be performed so that engineering geologists can mitigate the
hazards associated with active faulting by identifying the location of active faults and
allowing for a setback from the zone of previous ground rupture.
The site is located approximately 6.4 kilometers from the Rose Canyon Fault. Portions of the
Rose Canyon Fault have been included in the Alquist-Priolo Earthquake Fault Zone.
However, the possibility of damage due to ground rupture is considered low since active
faults are not known to cross the site.
Secondary effects of seismic shaking resulting from large earthquakes on the major faults in
the Southern California region, which may affect the site include ground lurching and
shallow ground rupture, soil liquefaction, dynamic settlement, seiches and tsunamis. These
secondary effects of seismic shaking are a possibility throughout the Southern California
region and are dependant on the distance between the site and causative fault and the onsite
geology. The major active faults that could produce these secondary effects include the Rose
Canyon, Newport-Inglewood, Coronado Bank, Elsinore-Julian, Elsinore-Temecula, Elsinore-
Glen Ivy and Palos Verdes Faults. A discussion of these secondary effects is provided in the
following sections.
2.6.1 Lurching and Shallow Ground Rupture
Soil lurching refers to the rolling motion on the ground surface by the passage of
seismic surface waves. Effects of this nature are not likely to be significant where the
thickness of soft sediments does not vary appreciably under structures.
Ground rupture due to active faulting is not likely to occur on site due to the absence
of known active fault traces. Minor cracking of near-surface soils due to shaking
from distant seismic events is not considered a significant hazard, although it is a
possibility at any site, and is often associated with ridgelines.
2.6.2 Liquefaction and Dynamic Settlement
Liquefaction and liquefaction-induced dynamic settlement of soils can be caused by
strong vibratory motion due to earthquakes. Liquefaction is typified by a buildup of
pore-water pressure in the affected soil layer to a point where a total loss of shear
strength occurs, causing the soil to behave as a liquid. Liquefaction primarily occurs
in loose, saturated, granular soils while cohesive soils such as silty clays and clays
are generally not considered susceptible to soil liquefaction. The effect of
liquefaction may be manifested at the ground surface by rapid settlement and/or sand
boils.
Due to the relatively dense nature of proposed compacted fill and the underlying
terrace materials (based on blow counts obtained from our iny~s,ti.g~g.!1) and the lack
of shallow ground water, the po:!~!!!mlJoL1Tqti€faeti0h-is-considered-ve:f;I;w.;::::7
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2.6.3 Tsunamis and Seiches
Based on the distance of the site from the sea and other large bodies of water, the
possibility of seiches and/or tsunamis affecting the site is considered to be low.
2.7 Sezsmzclty
The main seismic parameters to be considered when discussing the potential for earthquake-
induced damage on site are the distances to the causative faults, earthquake magnitudes, and
expected ground accelerations. We have performed site-specific analysis based on these
seismic parameters for the site and the onsite geologic conditions. The results of our analysis
are discussed in terms of the ''Design-Basis Earthquake Ground Motion" which is defined as
the ground motion that has a 10 percent chance of being exceeded in 50 years (Uniform
Building Code, u.B.C., 1997, Section 1627).
As discussed above, the site is not located in a seismic hazard zone or within an area covered
by Alquist-Priolo Earthquake Fault Zoning Maps. The nearest active fault to the site is the
Rose Canyon Fault.
From a probabilistic standpoint, the design earthquake (defined as a 10 percent probability of
exceedance in 50 years. 1997 U.B.C.l2001 C.B.C.) is estimated to produce a peak horizontal
ground acceleration (PGA) of0.27g. Refer to Appendix D.
2.8 Slopes
Based on our understanding of the proposed regrading of the site, we anticipate that small
slopes may be required to achieve the design elevations. Onsite graded slopes will be of 2: 1
(horizontal to vertical) inclinations or flatter and will be constructed utilizing fill material
generated from the cut portions of the site (overexcavation). Although specific design
elevations within the site have not been finalized at this time, we do not anticipate the design
fill slopes to exceed 5-to-1O feet in height. In general, we anticipate that the proposed 2: 1
(horizontal to vertical) fill slopes, utilizing fill soils derived from the onsite materials, will be
grossly stable. Recommendations for the construction of design fill slopes are contained in
Section 4.2 of this report.
2.9 Rippabilit;y
Based on the excavation characteristics encountered during our subsurface investigation,
rippability should not be an issue during site regrading and construction. The existing fill
materials on the site are anticipated to be excavatable with conventional heavy-duty
construction equipment.
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2.10 Oversized Material
Based on our site investigation, oversize material (greater than 8-inches in maximum
dimension) is unlikely but may be encountered in limited quantities scattered through the
existing fill material. If encountered, recomrriendations are provided for appropriate handling
of oversized materials in Appendix E.
2.11 Expansiye Soil Characteristics
Expansion index testing from a near-surface soil sample performed as part of this
investigation indicated a "very low" expansion potential (1997 U.B.C.l2001 C.B.C., EI20-
90). While isolated areas of higher expansion may be encountered, mixing with the less
expansive soils, which comprise the majority of the site, may help dilute these materials.
2.12 Corrosion Potential
A corrosion suite (pH, rmrumum resistivity, soluble sulfate, and chloride content) was
performed on a sample obtained from the upper 5 feet of boring LGC-3 to estimate the
corrosion potential of onsite soils. The resistivity tests resulted in a minimum resistivity of
6,140 ohm-centimeters, a pH of 6.1, and chloride content of 53 .parts per million (ppm). The
result of the soluble sulfate content test was less than 0.1 percent (96 ppm), "negligible" per the
1997 U.B.C.l2001 c.B.C. Table 19-A-4. Caltrans defines a corrosive area where any of the
following conditions exist: the soil contains more than 500 ppm of chlorides, more than 2,000
ppm (0.2 percent) of sulfates, or a pH of 5.5 or less.
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3.0 CONCLUS1QNS
Based on the results of our subsurface investigation and our understanding of the proposed
development, it is our opinion that the proposed development is feasible from a geotechnical
standpoint, provided the recommendations contained in the following sections are incorporated during
site grading and construction. A summary of our geotechnical conclusions follows':
• Based on our investigation and review of pertinent geologic maps and reports, the majority of the
site is underlain by undocumented artificial fill materials, which are in-tum underlain by
Quaternary Terrace materials.
• Based on laboratory consolidation testing of onsite undocumented fill soils, collapse at water
inundation was up to approximately 4 percent. Therefore, existing undocumented fill soils are
considered susceptible to collapse and should be removed and recompacted for future
development.
• Active or potentially active faults are not known to exist on the site. The nearest know active fault
to the site is the Rose Canyon Fault located approximately 6.4 km from the site.
• The main seismic hazard that may affect the site is from ground shaking from one of the active
regional faults. The maximum anticipated bedrock acceleration on the site due to a maximum
probable earthquake (10 percent probability of exceedance in 50 years) is estimated to be 0.27g.
• Due to the dense nature of the underlying Quaternary Terrace materials, proposed compacted fill to
design grades, and the lack of a shallow ground-water table, the potential for liquefaction is
considered low.
• Based on limited laboratory test results, the onsite soils are anticipated to have a "very low" to
"low" potential for expansion. However, this should be confirmed at the completion of site
regrading.
• Based on limited laboratory test results, the onsite soils have a negligible potential for soluble
sulfate attack on normal concrete. However, this should be confirmed at the completion of
regrading.
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4.0 RECOMMRNDA VONS
The following recommendations for design and construction of the proposed development should be
considered as a minimum from a geotechnical viewpoint. More restrictive design criteria may be
required by others including the owner, architect, structural engineer, and local governing agencies.
4.1 Site Earthwork
We anticipate that earthwork at the site will consist of rough and precise grading operations
followed by retaining wall construction, utility construction, foundation construction, and
asphalt paving of the streets and drives. We recommend that earthwork onsite be performed in
accordance with the following recommendations, the City of Carlsbad Grading Requirements,
and the General Earthwork and Grading Specifications for Rough Grading included in
Appendix E. In case of conflict, the following recommendations shall supersede all previous
recommendations and those included as part of Appendix E. The following recommendations
should be considered preliminary and may be revised based on the actual as-graded conditions
of the site once grading is completed. If necessary, revisions will be provided in our as-graded
report for the site following the completion of grading.
4.1.1
4.1.2
Site Prenaration ...
Prior to grading, the site should be cleared of surface obstructions and potentially
compressible material, such as vegetation, stockpiled material, undocumented fill and
desiccated terrace materials (see below). Vegetation and debris should be remove,d ~nd
properly disposed of offsite.
Removal aud Recomnactiou ..
The upper approximately 20 feet consists of undocumented artificial fill, which is
considered geotechnically unsuitable for supporting the proposed structures and
improvements. Removals should include excavation of the existing undocumented fill
soils until a suitable bottom into the underlying terrace deposit is achieved. Localized,
deeper removals in the terrace material may be recommended where deemed necessary
by the geotechnical consultant based on observations during grading.
Removal bottoms should be observed and accepted by the geotechnical consultant prior
to fill placement. From a geotechnical perspective, ~ateria:l-that-is-rem0ved-m:aY:De :J
pIacea:as':"fiU-pr,o;v.ldea':lli:e material is relatively free of organic materiaraiidlor
deleterious debris, is moisture-conditioned or dried (as needed) to obtain above-
optimum moisture content, and then recompacted prior to additional fill placement or
construction. Areas tQ receive fill and/or 0!4~r surface improvements should be
scarified, moisture conditioned, and recompa<;:ted to at least 90 percent relative
compaction (based on American Society for Testing and Materials [ASTM] Test
Method D1557).
Project No. 041065-02 Page 11 February 25,2005
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4.1.3
4.1.4
4.1.5
Temporaq Stability of Removal Excavations
Due to the recommended depth of remedial grading, minor temporary slopes will exist
around the perimeter of the site. We do not expect these slopes to be grossly unstable,
however, all excavations should be made in accordance with Cal OSHA requirements.
Temporary excavations greater than 5 feet high should be laid back at an appropriate
inclination.
Settlement of existing ground surfaces can often occur due to deep excavations and cuts
nearby. Such settlement may cause distress or damage to structures and improvements
located in close proximity to the excavation. Where existing structures or
improvements are located within 15 feet of a temporary excavation, appropriate shoring
methods may be necessary in accordance with the applicable OSHA codes and
regulations.
EiZl Placement and Comnaction ..
From a geotechnical perspective, the onsite soils are generally suitable for use as
compacted fill, provided they are screened of organic materials and construction debris.
Areas prepared to receive structural fill and/or other surface improvements should be
scarified, brought to at least optimum-moisture content, and recompacted to at least 90
percent relative compaction (based on ASTM Test Method DI557). The optimum lift.
thickness to produce a uniformly compacted fill will depend on the type and size of
compaction equipment used. In general, granular fill should be placed in uniform lifts
not exceeding 8 inches in compacted thickness. Generally, placement and compaction
of fill should be performed in accordance with local grading ordinances under the
observation and testing of the geotechnical consultant. Oversized material (material
larger than 8 inches in maximum dimension) should be placed in accordance with the
recommendations provided in Appendix E.
From a geotechnical viewpoint, import soils (if necessary) should consist of clean,
granular soils of very low expansion potential (expansion index 20 or less based on
V.B.C. 18-2). Source samples should be provided to the geotechnical consultant for
laboratory testing a minimum of 48 hours (2 full working days) prior to any planned
importation.
Pln.cement of Expansive Soils
If expansive soils are encountered during grading, we recommend they be placed in the
deeper fill areas of the site. Soils having an expansion index of 50 or greater (based on
V.B.c. 18-2) preferably should not be placed within 4 vertical feet of proposed
structures or other improvements. If, however, phl,~~ment of expansive soils near finish
grade is unavoidable, additional recommendations can be provided to mitigate the
potential expansive soil related problems. We recommend representative samples of the
finish grade soils on the site be collected at the completion of grading and laboratory
tested for expansion potential.
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4.2
4.1.6 Fill Settlement
Due to the self-weight consolidation of the fill and underlying soils, some amount of
settlement will occur during the project design life. Based on the results of our site
study and the recommended remedial grading, we estimate the post-construction
settlement of the site due to self-weight of the material will be negligible.
4.1. 7 Shrinkage and Bulking
Allowance in the earthwork volumes budget should be made for an estimated 0 to 10
percent reduction in volume of the recompacted loose and porous undocumented fill
soils. This value was estimated from limited laboratory test data and our experience
on similar projects with similar soil types. It should be stressed that these v;alues are
only estimates and that an aC1JJal shrinkage factor would be extremely difficult to
predetermine. The type of compaction equipment and method of compaction used by
the contractor will also influence the shrinkage of onsite soils.
4.1.8 Trench Baclifill and Compaction
The onsite soils may generally be suitable as trench backfill provided the soils are
screened of organic matter, rocks and other material greater than 6 inches in diameter.
If trenches are shallow or the use of conventional equipment may result in damage to
the utilities, clean sand having a Sand Equivalent (SE) of 30 or greater should be used
to bed and shade the pipes. Sand backfill should be water-densified by jetting and then
tamping to ensure adequate compaction. Otherwise, trench backfill should be
compacted in uniform lifts (generally not exceeding 12 inches in compacted thickness)
by mechanical means to at least 90 percent relative compaction (per ASTM Test
Method D1557). A representative from LGC should observe and test the backfill to
verify compliance with the project specifications
Slape Stahilit)!
4.2.1 Cllt Slopes
No design cut slopes are anticipated at the site.
4.2.2 Fill Slopes
Design fill slopes with a slope ratio of 2: 1 (horizontal to vertical), are anticipated to
be both grossly and surficially stable as designed, as long as they are constructed in
accordance with the Standard Earthwork and Grading Specifications included in
AppendixE.
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4.3
4.4
Seismic Design Criteria
The soil parameters in accordance with the 1997 D.B.c. and the 2001 California Building Code
(Section 1636) are as follows:
Soil Profile Type (Table 16-J) = SD
Seismic Zone (Figure 16-2) = 0.4
Seismic Source Type (Table 16-U) = B
Peak Horizontal Ground Acceleration for Design Base Earthquake: 0.27g (Refer to
Appendix D)
Na = 1.0
Ny = 1.1
Soil Rearing
An allowable soil bearing pressure of 1,500 pounds per square foot (pst) may be used for the
design of footings having a minimum width of 12 inches and minimum embedment of 18
inches below lowest adjacent ground surface. This value may be increased by 300 psf for
each additional foot of embedment of 100 psf for each additional foot of foundation width to
a maximum value of 2,500 psf. These allowable bearing pressures are applicable for level
(ground slope equal to or flatter than 5H: 1 V) conditions only.
In utilizing the above-mentioned allowable bearing capacity, foundation settlement due to
~tructuralloads is anticipated to be less than 1 total inch and less than Yz-inch over a horizontal
span of 30 feet.
Resistance to lateral loads can be provided by friction acting at the base of foundations and
by passive earth pressure. A coefficient of friction of 0.35 may be assumed with dead-load
forces. An ultimate passive lateral earth pressure of 300 psf per foot of depth (pct) to a
maximum of 3,000 psf may be used for the sides of footings poured against properly
compacted fill. This passive pressure is applicable for level (ground slope equal to or flatter
than 5H: 1 V) conditions only.
Bearing values indicated above are for total dead loads and frequently applied live loads. The
above vertical bearing may be increased by one-third for short durations of loading which will
include the effect of wind or seismic forces. The passive pressure may be increased by one-third
due to wind or seismic forces.
. Project No. 041065-02 Page 14 February 25, 2005
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4.5 Provisional Foundation Recommendations
Due to the anticipated very low to low expansion potential of onsite soils, we have provided
foundation design considerations for both conventional and post-tensioned slab systems.
Detailed design recommendations are provided in the following sections.
4.5.1 Conventional Slab-on-Ground Foundations
Conventional footings may be used on lots underlain by less than 30 feet of
compacted fill and an expansion index less than 20 (very low) per D.B.C. test method
18-2. A representative sample of the near-surface soils should be tested for expansion
potential at the end of rough grading to confirm the final recommended foundation
system. Minimum footing depths should be 18 inches for two story buildings. Slab
subgrade should be presoaked to optimum moisture content to a minimum depth of 12
inches. Structural steel reinforcement should be designed by the structural engineer.'
4.5.2 Post-Tensioned Foundation Design Parameters
If near-surface soils have an expansion index greater than 20 or structures are
proposed on more than 30 feet of compacted fill, we recommend a post-tensioned
slab system is applied using the geotechnical parameters provided in Table 1. These
parameters have been determined in general accordance with Chapter 18 of the
California Building Code (CBC, 2001 edition). In utilizing these parameters, the
foundation engineer should design the foundation system in accordance with the
allowable deflection criteria of applicable codes and the requirements of the
structural engineer/architect. Other types of stiff slabs may be used in place of the
CBC post-tensioned slab design provided that, in the opinion of the structural
engineer, the alternative type of slab is at least as stiff and strong a~ that designed by
the CBC method.
The post-tensioned design methodology outlined in CBC Chapter 18 is in part based
on the assumption that soil-moisture changes around and beneath the post-tensioned
slabs are influenced only by climatological conditions. Soil-moisture change below
slabs is the major factor in foundation damage relating to expansive soil. The CBC
design methodology has no consideration for presoaking, homeowner irrigation, or
other non-climate related influences on the moisture content of subgrade soils. In
recognition of these factors, and our previous experience and work on the
geotechnical PTI subcommittee, we have modified the geotechnical parameters
obtained from this methodology to account for man-made conditions, influence of
irrigation, and climate. Our design parameters are based on our experience with
similar residential projects and the anticipated nature of the soil (with respect to
expansion potential). Please note that implem~p.tation of our recommendations will
not eliminate foundation movement (and related distress) should the moisture content
of the subgrade soils fluctuate. It is the intent of these recommendations to help
maintain the integrity of the proposed structures and reduce (not eliminate)
movement, based upon the anticipated site soil conditions.
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4.5.3 Foundation Suhgrade Preparation and Maintenance
4.5.4
Presoaking of the subgrade soils is recommended prior to trenching the foundation.
Presoak recommendations specific to the anticipated site soil conditions are
presented in Table 1. This subgrade moisture condition should be maintained up to
the time of concrete placement. Furthermore, the moisture content of the soil around
the immediate perimeter of the slab should be maintained at near optimum-moisture
content (or slightly above) during construction and up to occupancy of.the homes.
The geotechnical parameters provided in Table 1 assume that if the areas adjacent to
the foundation are planted and irrigated, these areas will be designed with proper
drainage and adequately maintained so that ponding, which causes significant
moisture changes below the foundation, does not occur. Our recommendations do not
account for excessive irrigation andlor incorrect landscape design. Sunken planters
placed adjacent to the foundation, should either be designed with an efficient
drainage system or liners to prevent moisture infiltration below the foundation. Some
lifting of the perimeter foundation beam should be expected even with properly
constructed planters.
In addition to the factors mentioned above, future homeowners should be made
aware of the potential negative influences of trees andlor other large vegetation.
Roots that extend near the vicinity of foundations can cause distress to foundations.
Future homeowners (and the owners landscape architect) should not plant trees/large
shrubs closer to the foundations than a distance equal to half the mature height of the
tree or 20 feet, whichever is more conservative unless specifically provided with root
barriers to prevent root growth below the house foundation.
It is the homeowner's responsibility to perform periodic maintenance during hot and
dry periods to insure that adequate watering has been provided to keep soil from
separating or pulling back from the foundation. Future homeowners should be
informed and educated regarding the importance of maintaining a constant level of
soil-moisture. The owners should be made aware of the potential negative
consequences of both excessive watering, as well as allowing potentially expansive
soils to become too dry. Expansive soils can undergo shrinkage during drying, and
swelling during the rainy winter season, or when irrigation is resumed. This can
result in distress to building structures and hardscape .improvements. The builder
should provide these recommendations to future homeowners.
Val10r Retarder and Sand Below Slabs ..
Interior floor slabs with moisture sensitive floor coverings should be underlain by a
15-mil thick polyolefin (or equivalent) moisture/vapor retarder to help reduce the
upward migration of moisture from the underlying subgrade soils. The
moisture/vapor retarder product used should meet the performance standards of an
ASTM E 1745 Class-A material, and be properly installed in accordance with ACI
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publication 302. It is the responsibility of the contractor to ensure that the
moisture/vapor retarder systems are properly placed in accordance with the project
plans and specifications, and that the moisture/vapor retarder materials are free of
tears and punctures prior to concrete placement. Additional moisture reduction
and/or prevention measures may be needed, depending on the performance
requirements of future interior floor coverings.
Recommendations are traditionally included with geotechnical foundation
recommendations for sand layers placed below slabs and abovelbelow vapor
retarders for the purpose of protecting the retarder and to assist in concrete curing.
Sand layer requirements are the purview of the foundation engineer/structural
engineer, and should be provided in accordance with ACI Publication 302 "Guide for
Concrete Floor and Slab Construction". We have provided recommendations in
Table 1 that we consider to be a minimum from a geotechnical perspective. These
recommendations must be confirmed (and/or altered) by the foundation engineer,
based upon the performance expectations of the foundation. Ultimately, the design of
the moisture retarder system and recommendations for concrete placement and
curing are the purview of the foundation engineer, in consideration of the project
requirements provided by the architect and developer.
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TABLEl
Preliminary Geotechnical Parameters for Post-Tensioned Foundation Slab Design
Parameter Value
Exoansion Index Low I
Clay_ Mineral Type Montmorillonite. (assumed)
Thornthwaite Moisture Index -20
Depth to Constant Soil Suction (depth to constant 7 feet moisture content over time but within CBC limits)
Constant Soil Suction PF3.6 -Moisture Velocitv 0.7 inches/month
Center Lift
Edge moisture variation distance, em 5.5 feet
Center lift Vm 2.0 inches
Edge Lift
Edge moisture variation distance, em 3.0 feet
Edge lift. Ym 0.75 inches
Modulus of Subgrade Reaction, k (assuming presoaking 200 pci as indicated below)
Perimeter foundation embedment below finish grade (for 18 inches a conventional PT foundation)
Presoak Optimum moisture content to a-
minimum depth of 12 inches
15 mil polyolefin or equivalent
Under slab moisture retarder and sand layers overlain by 1 inch of dr):: sand; Also
2 Refer to Text
1. Assumed for preliminary design purposes. Further evaluation is needed at the completion of
grading.
2. Recommendations for sand below slabs are traditionally included with geotechnical
foundation recommendations, although they are not the purview of the geotechnical consultant.
The sand layer requirements are the purview of the foundation engineer/structural engineer, and
should be provided in accordance with ACI Publication 302 "Guide for Concrete Floor and Slab
Construction" .
4.6 Wteral Earth Pressures and Retaining Wall Design Considerations
Retaining walls should be backfilled with approved materials having a very low expansion
potential (El :::; 20) and a Sand Equivalent (SE) of at least 30. On site materials may be
acceptable for retaining wall backfill provided they meet these criteria. A representative sample
should be collected and submitted to our laboratory for EI and SE testing upon completion of
grading. Specific recommendations for top of slope retaining walls are provided in Section 4.7.
The recommended lateral pressures for approved free-draining sand backfill for level or sloping
backfill are presented in Table 2.
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TABLE 2
lp,teral Barth Pressures/or Approved Sails
Equivalent Fluid Weight (pcf)
Conditions Level Backfill 2:1 Backfill Sloping Upwards
Active 35 50
At-Rest 60 85
Passive 300 (in front of wall) -
Lateral earth pressures are provided as equivalent fluid unit weights, in psf/ft of depth or pcf.
These values do not contain an appreciable factor of safety, so the civil af.ld/or structural
engineer should apply the applicable factors of safety and/or load factors during design. A soil
unit weight of 125 pcf may be assumed for calculating the actual weight of soil over the wall
footing.
Embedded structural walls should be designed for lateral earth pressures exerted on them. The
magnitude of these pressures depends on the amount of deformation that the wall can yield
under load. If the wall can yield enough to mobilize the full shear strength of the soil; it can be
designed for "active" pressure. If the wall cannot yield under the applied load, the shear
strength of the soil cannot be mobilized and the earth pressure will be higher. Such walls should
be designed for "at-rest" conditions. If a structure moves toward the soils, the resulting
resistance developed by the soil is the "passive" resistance. Only that soil which will continue
to remain in place in front of the wall should be considered to provide passive resistance. The
passive earth pressure values assumes sufficient slope setback (see previous section).
For design purposes, the recommended equivalent fluid pressure for each case for walls
founded above the static groundwater and backfilled with imported soils (sand equivalent of 30
or greater) is provided in Table 2. The equivalent fluid pressure values assume free-draining
conditions. The backfill soils should be compacted to at least 90 percent relative compaction
(based on ASTM Test Methods D2922 and D3017). The walls should be constructed and
backfilled as soon as possible after backcut excavation. Prolonged exposure of backcut slopes
may result in some localized slope instability. If conditions other than those assumed above are
anticipated, the equivalent fluid pressure values should be provided on an individual-case basis
by the geotechnical engineer.
Surcharge loading effects from the adjacent structures should be evaluated by the geotechnical
and structural engineers. Retaining wall structures should be provided with appropriate
drainage and appropriately waterproofed. The outlet pipe should be sloped to drain to a suitable
outlet. Typical wall drainagE< g~sign is illustrated on Figure 3. It should be noted that the
recommended subdrain does not provide protection against seepage through the face of the wall
and/or efflorescence. Efflorescence is generally a white crystalline powder (discoloration) that
results when water, which contains soluble salts, migrates over a period of time through the
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face of a retaining wall and evaporates. If such seepage or efflorescence is undesirable,
retaining walls should be waterproofed to reduce this potential.
Excavations should be made in accordance with CAL OSHA, as a general guideline. The
backfill soils should ·be compacted to at least 90 percent relative compaction (based on ASTM
Test Methods D2922 and D3017). The walls should be constructed and backfilled as soon as
possible after backcut excavation. Prolonged exposure of backcut slopes may result in some
localized slope instability. Excavation safety is the sole responsibility of the contractor.
4.7 Retaining Walls at the Top-of-Slopes
Retaining walls located at the top of slopes should be constructed on caissons. The following
geotechnical parameters may be used for the design:
For the sloping condition, an ultimate passive resistance of 150 pcf (ignoring the upper 3
feet) to a maximum 2,250 psf may be used. While ignoring the upper three feet of passive
resistance, the contribution of the weight of this soil may be included in computing the
passive resistance. For isolated pile conditions spaced a minimum of 3 diameters, the passive
pressure may be doubled. For a minimum lO-foot vertical long caisson, an allowable skin
friction and allowable end bearing of 300 Ibs/ft2 and 5,000 Ibs/ft2, respectively may be used.
The upper 3 feet of skin friction should be neglected. The caissons should be designed by the
structural engineer and be a minimum of 12 inches in diameter. The surcharge load from any
proposed structures within a 1: 1 projection of the toe of the proposed retaining walls should
be taken into account in the wall. Lateral earth pressures provided in Section 4.6
4.8 Proposed Tiered Retaining Wall System
Based on the provided conceptual plan, the southern portion of the site will contain tiered
retaining walls with a maximum anticipated height of approximately 6 feet for each wall. The
lower should be designed to accommodate the structural load of the above wall. When the
grading plan is available, slope stability analysis should be performed on the tiered wall system
in order to verify that global static and seismic factors of safety are adequate for the proposed
design.
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EXTENT OF APPROVED BACKFILL MATERIAL, MIN.
HEEL WIDTH OR H/2 WHICH
NATIVE BACKFILL COMPACTED
TO MINIMUM 90% RELATIVE
COMPACTION PER ASTM1557-D
1'MINIMUM
WATER PROOFING PER CIVIL ENGINEER -"""""':..,-.-'+-<'---.,...;:..,....,--=-r-.:;..;.,.'O'-"':'...,....,..~.,:..-:..;,-,--'-;.,....:...,.....:,..,.,,..:....,"'"'"'1~..,,....~
APPROVED ONSITE MATERIAL
(EI < 30) ----~~....,.:.;,.,..,....:.~"i.
BACKCUT PER OSHA ------1
MINIMUM 1 CUBIC FOOT PER LINEAR FOOT
BURRITO TYPE SUB DRAIN, CONSISTING OF
3/4 INCH CRUSHED ROCK WRAPPED IN
MIRAFI 140N OR APPROVED EQUIVALENT
4 INCH DIAMETER, SCHEDULE 40 PERFORATED ____ -\-"""---,~,;....;_~.;;...;_.:..o...,..~
PVC PIPE TO FLOW TO DRAINAGE DEVICE
FOOTINGIWALL DESIGN PER CIVIL ENGINEER -------+-===;~==;:=;:==-=~;a.!..a
Version 1210712001
LGC FIGURE 3
Retaining Wall
Approved Onsite
Material Backfill
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4.9 PrelimjnaQ! Pavement Sections
Based on an assumed R-value of 25, we recommend the following provisional minimum street
sections for Traffic Indices of 4.5, 5, and 6. These recommendations should be confirmed with
R-value testing of representative near-surface soils at the completion of grading and after
underground utilities have been installed and backfilled. Final street sections should be
confirmed by the project civil engineer based upon the design Traffic Index. In addition,
additional sections can be provided based on other traffic indices.
Assumed Traffic Index 4.5 5 6
R -Value Sub!!rade 25 25 25
AC Thickness 4.0 inches 4.0 inches 4.5 inches
Base Thickness 4.0 inches 5.5 inches 7.0 inches
The thicknesses shown for are minimum thicknesses. Increasing the thickness of any or all of
the above layers will reduce the likelihood of the pavement experiencing distress during its
service life. The above recommendations are based on the assumption that proper
maintenance and irrigation of the areas adjacent to the roadway will occur through the design
life of the pavement. Failure to maintain a proper maintenance and/or irrigation program may
jeopardize the integrity of the pavement.
Aggregate base should conform to the requirements of the 2000 edition of the Standard
Specifications for Public Works Construction ("Greenbook"). Aggregate base should be
compacted to a minimum of 95 percent relative compaction over subgrade compacted to a
minimum of 90 percent relative compaction per ASTM-D 1557.
4.10 Couosjvjt)! to Concrete and Metal
Although we are not corrosion engineers (LGC is not a corrosion consultant), several
governing agencies in Southern California require the geotechnical consultant to determine
the corrosion potential of soils to buried concrete and metal facilities. We therefore present
the results of our testing with regard to corrosion for the use of the client and other
consultants as they determine necessary. Recommendations for mitigation should be
obtained from a corrosion engineer.
Based on preliminary testing performed at the site concrete should be minimally designed in
accordance with the negligible category of Table 19-A-4 of 1997 U.B.C.l2001 C.B.C. This
should be verified based on as-graded conditions.
4.11 Nonstrnctnral Concrete Flatwork
Concrete flatwork (such as Wfl~lcways, bicycle trails, ~tc.) has a high potential for cracking
due to changes in soil volume related to soil-moisture fluctuations. To reduce the potential
for excessive cracking and lifting, concrete should be designed in accordance with the
minimum guidelines outlined in Table 3. These guidelines will reduce the potential for
irregular cracking and promote cracking along construction joints, but will not eliminate all
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cracking or lifting. Thickening the concrete and/or adding additional reinforcement will
further reduce cosmetic distress.
TABLE 3
Nonstructural Concrete Flatwork for low EX12ansion Potential v ...
Homeowner City Sidewalk
Sidewalks Private Drives PatioslEntryways Curb and
Gutters
Minimum
Thickness (in.) 4 (nominal) 5 (full) 5 (full) City/Agency
Standard .-
Wet down prior Presoak to 12 Presoak to 12
Presoaking to placing inches inches City/Agency
Standard
No.3 at 24 No.3 at 24 inches
Reinforcement -inches on on centers City/Agency
centers Standard
Thickened Edge
(in.) -8x8 -City/Agency
Standard
Saw cut or deep Saw cut or deep Saw cut or deep
open tool joint open tool joint open tool joint to a
Crack Control to a minimum to a minimum of minimum of 1/3 the City/Agency
Joints of 113 the 113 the concrete concrete thickness Standard
concrete thickness
thickness
10 feet or
Maximum Joint 5 feet quarter cut 6 feet City/Agency
Spacing whichever is Standard
closer
Aggregate Base
Thickness (in.) --2 City/Agency
Standard
To reduce the potential for driveways to separate from the garage slab, the builder may elect
to install dowels to tie these two elements together. Similarly, future homeowners should
consider the use of dowels to connect flatwork to the foundation.
4.12 Control o/Surface Water and Drainage Control
Positive drainage of surface water away from structures is very important. Water should not be
allowed to pond adjacent to buildings or to flow freely down a graded slope. Positive drainage
may be accomplished by providing drainage away from buildings at a gradient of at least 2
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percent for earthen surfaces for a distance of at least 5 feet, and further maintained by a swale
or drainage path at a gradient of at least 1 percent. Where necessary, drainage paths may be
shortened by use of area drains and collector pipes. Eave gutters are recommended and should
reduce water infiltration into the sub grade soils if the downspouts are properly connected to
appropriate outlets.
Planters with open bottoms adjacent to buildings should be avoided. Planters should not be
designed adjacent to buildings unless provisions for drainage, such as catch basins, liners,
and/or area drains, are made. Over watering must be avoided.
4.13 Freestanding WqllS
To reduce the potential for unsightly cracks due to differential settlement or possibly
expansive soils, we recommend the inclusion of construction joints at a maximum spacing of
20 feet on center. The structural engineer, based upon the wall reinforcement, may alter this
spacing. If the soil-moisture content below the wall foundation varies significantly, some
wall movement should be expected; however, this movement is unlikely to cause more than
cosmetic distress. Allowable soil bearing values for wall footing design are provided in
Section 4.5.
4.14 Review ofPraject P1n.ns·
Grading plans Crough and precise), foundation plans, final project drawings should be reviewed
by this office prior to construction to verify that our geotechnical recommendations have been
incorporated.
4.15 Construction Observation and Testing
The recommendations provided in this report are based on limited subsurface observations and
geotechnical analysis. The interpolated subsurface conditions should be checked in the field
during construction by a representative ofLGC.
Construction observation and testing should also be performed by the geotechnical consultant
during future grading, excavations, backfill of utility trenches, preparation of pavement
sub grade and placement of aggregate base, foundation or retaining wall construction or when
any unusual soil conditions are encountered at the site.
Project No. 041065-02 Page 24 February 25, 2005
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5.0 LlMlTA TTQNS
Our services were perfonned using the degree of care and skill ordinarily exercised, under similar
circumstances, by reputable engineers and geologists practicing in this or similar localities. No
other warranty, expressed or implied, is made as to the conclusions and professional advice
included in this report. The samples taken and submitted for laboratory testing, the observations
made and the in-situ field testing perfonned are believed representative of the entire project;
however, soil and geologic conditions revealed by excavation may be different than our
preliminary findings. If this occurs, the changed conditions must be evaluated by the project soils
engineer and geologist and design(s) adjusted as required or alternate design(s) recommended.
This report is issued with the understanding that it is the responsibility of the owner, or of
his/her representative, to ensure that the infonnation and recommendations contained herein are
brought to the attention of the designer andlor project engineer and incorporated into the plans,
and the necessary steps are taken to see that the contractor andlor subcontractor properly
implements the recommendations in the field. The contractor andlor subcontractor should notify
the owner if they consider any of the recommendations presented herein to be unsafe.
The findings of this report are valid as of the present date. However, changes in the conditions
of a property can and do occur with the passage of time, whether they be due to natural
processes or the works of man on this or adjacent properties. Therefore, the findings,
conclusions, and recommendations presented in this report can be relied upon only if LGC has
the opportunity to observe the subsurface conditions during grading and construction of the
project, in order to confirm that our preliminary findings are representative for the site.
In addition, changes in applicable or appropriate standards may occur, whether they result from
legislation or the broadening of knowledge. Accordingly, the findings of this report may be
invalidated wholly or partially by changes outside our controL Therefore, this report is subject
to review and modification, and should not be relied upon after a period of 3 years.
Project No. 041065-02 Page 25 February 25, 2005
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Afu
'Qt
-?
LGC-5
~
TD=16'
LEGEND
Artificial Fill -Undocumented
Quaternary Terrace Deposits, Encircled Where
Buried
Approximate Geologic Contact, Querried Where
Uncertain
APPROXIMATE LOCATION OF
GEOTECHNICAL BORING, WITH TOTAL
DEPTH INDICATED
60' 0 60' 120' i ' i i ___ •
GEOTECHNICAL CROSS-SECTION A -A'
h PI • Existing Topograp Y I Proposed Deslgn A'
A \ . / 20 r--.::;:::
~1I0
La V ..... 111t------s ---------..... y 8 90 100 110 12Q 130 140 150 160 ....... 900 10 20 30 ~o .so ~ 70 ~lstance (ft)
Figure 2
Geotechnical Map
Cottage Development
Poinsettia Lane & Paseo Del Norte
Carlsbad, California
./
-:..... :"":.-::M~-,
,.:
.~ ~-~ :.:'" . •• "': ••••••• M :.~ _ _' ___ .'. A r .. . " . • 0 .· .• c;~vc:~ __ --/-;;;»
__ --.--~. ______ . ".~_-D A r iJ nf::; /I .!JQ "U . . '<.\ t '_'_'-'-, ~ (I I rT'l Ti, I 17 ,~--.-----~-~ -
.'':'-<. ,'., ".: .
,'.-"
I·' .J
.,
,f;
;;
I .
, ..... >'
M, :~.-,
, /"': ",'
.'.:~-::...
','-
,i."_
I
I
-------.-. . ~ . o .
""'
~-'?---7.5· RETAHN.G WAll. -.: .:" ..... -"1---'--__ _ 1063 1063 6' SOUND WIJl.(TrP)
__ -7-_._ _ _ _ "" ~ \"~-" ~~N"G WAU(VARES) __ 1
- - --1-- _ --1-____ '! ______ ?.f..RCf..OSI£2.6'_~N!S ~l.. -'1-- -
-._-.:----~..!:::'--. '._-'-."'" -.-~-.. ~. L '" --' -' ... _. _~J_: __ . _. " ..
OtF-Ri,MP .:' ...
, . '" :;:;:. -"='::':
. -.... "--------
PROPERTY OWNER:
Cottage Development Company
209 A venida Del Mar, Suite 204
San Clemente, CA 92672
--:~-.. '; ... --
~
CIVIL ENGINEER:
Rick Engineering Company
5620 Friars Road
San Diego, CA 92110
,
.'
_:: .. < . ~---... ::-:.':'.:--.. -
... -.. '
.. :;_.--.
.. :. ::.: ...
.. -...
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I Appendix A
I References
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APPENDIX A
References
American Concrete Institute, 1985, Manual of Concrete Practice, Parts 1 and 2.
Blake, 1998, UBCSEIS computer program, Version 1.03.
___ , 1999, FRISKSP computer program, Version 4.0.
California Division of Mines and Geology, 1996, "Probabilistic Seismic Hazard Assessment for the
State of California", 69-08, USGS Open Files Report 96-706. DMG Open File Report.
International Conference of Building Officials (lCBO), 1997, Uniform Building Code, Volume ll.
___ ,2001, California Building Code, Volume ll.
Kennedy, M.P., 1975, Geology of the San Diego Metropolitan Area, California, California Division of
Mines and Geology, Bulletin 200, Plate 1B, dated 1975.
Lawson and Associates Geotechnical Consulting, Inc., 2004, Preliminary Results of Geotechnical
Investigation of Proposed 23-Lot Residential Development, Southwest of the Intersection of
Poinsettia Lane and Paseo Del Norte in Carlsbad, California, Project No. 041065-01, Dated
July 26,2004.
R.C. Jewett Company, 1981, Preliminary Soils and Geologic Investigation, Proposed 5.1 Acre Site for
Commercial/ Industrial Development, Carlsbad, California, Project No. SD1992(3), Dated
August 31, 1981.
Rick Engineering Company, 2005, Conceptual Site Plan, February 2005.
Project No. 041065-02 PageA-1 February 25, 2005
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I Appendix B
I Boring Logs
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ISymbol1
SA
H
SHA
-200
AL
MAX
OS
RDS
TRI
EI
P
CN
COL
UC
S
pHR
COR
RV
Key to Laboratory Test Symbols
Laboratory Test I
Sieve Analysis
Hydrometer Analysis
Sieve & Hydrometer Analysis
Percent Passing #200 Sieve
Atterberg Limits
Maximum Density
Undisturbed Direct Shear
Remolded Direct Shear
Triaxial Shear
Expansion Index
Permeability
Consolidation
Collapse
Unconfined Compression
Sulfate Content
pH & Resistivity
Corrosion Suite (pH, Resistivity, Chloride, Sulfate) .
R-Value
I Geotechnical Boring Log LGC-1
I
I
..... ::;:-
I Q) () ..a .3: (5 g 0> E ~ ..a -+-'
-+-' ~ en 0 ::J C ~ E Q)
c g ---1 Z ::J ·w >. I-0 .2 Q) 0 c Q) Cf) -.....
I ~ .c .c 0.. (.) Q) ::J Cf) 0 0 -+-' ..-0.. E :s: en (.) Q) > 0.. Q) co 0 c:-·0 Cf) 0.. Q) ..... co ~ W 0 <D Cf) CO 0 :2 :::)
I 114.5 0 8M @ 0' Silty Sand: reddish-brown, slightly moist to
8-1 moist
1 39 @ 2.5' Silty Sand: dark reddish-brown, slightly MAX
I 50 116.3 4.2 moist; massive
109.5 5 2 16 @ 5' Silty Sand: dark reddish-brown, slightly moist; I 22 massive 25
....... 8HA 3 32 @ 7.5' Silty Sand: dark reddish-brown, slightly moist I ....... 55 131.5 5.6
104.5 10 4 6 @ 10' Silty Sand: dark reddiSh-brown, slightly I 9
11 moist, dense; massive
5 18 @ 12.5' Silty Sand: dark reddish-brown, slightly eN
I 23 121.0 6.1 moist to moist, dense; trace organics 28
99.5 15 6 14 @ 15' Silty Fine Sand: medium to dark brown and
I 18 reddish-brown, slightly moist, dense; scattered
23 mottling, possible shell debris
,-7 14 I 22 116.7 6.1 8M @ 17.5' Silty Medium to Fine Sand: light brown, 40 brown and reddish-brown, slightly moist to moist,
94.5 20 18 dense; mottled
I 8 18
24 @ 20' Silty Medium to Fine SAND: light brown and
light reddish-brown, slightly moist, dense
I 9 @ 22.5' Silty Sand: light brown to light yellowish-
116.0 7.9 brown, slightly moist to moist, very dense
89.5 25 ....... 10 18 @ 25' Silty Sand: light brown to light yellowish I 22
27 brown, slightly moist to moist, to dense
I 11 119.9 6.8 @ 27.5' Silty Sand: reddish-brown to moderate
yellowish-brown, slightly moist to moist, very dense
84.5 30
I = Ring sample LAWSON & ASSOCIATES t8l = SPT sample GEOTECHNICAL CONSUL TING, INC. B-1 = Bulk sample
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--E-
e g 0 15 ..c > .......
Q) c... Q)
ill 0
84.5 30
79.5 35
74.5 40
69.5 45
64.5 50
59.5 55
O> 0 .....J
,2 ..c c... ell "-C)
Geotechnical Boring Log LGC·1
"----Q) U
..0 ..3: E ....... >. :J e -Z :J 'w 0 e Q) 0 Q) 0.. 0 E $: 0 c:-ell
C/) CO 0
• = Ring sample
~ = SPT sample
BULK = Bulk sample
~ 0 ----Q) "-:J ....... en '0
::2:
(5
..0 E >. C/)
C/) 0 C/) :::>
-Total Depth = 28'
-Backfilled with bentonite chips
-No Groundwater Encountered
LAWSON & ASSOCIATES
GEOTECHNICAL CONSULTING, INC.
....... en Q) l-
"f-0
Q) c... ~
I Geotechnical Boring Log LGC-2
I
I
..... .........
I ID 't5
..0 ...e, (5 ......... C> E ~ ..0 ......
iE. ...... >. C/)
0 ::J C :t:: 0 E Q)
-I Z --c g ::J C/) >. I-
0 .9 0 c Q) C/) Q) ..... -
I :g ..c ..c 0.. 0 Q) ::J C/) 0
0 ..... ..... 0.. :s: C/) 0 Q)
> 0.. E Q) co 0 C"-·0 0..
Q) ..... co C/)
iIi 0 CJ C/) co 0 ~ ::::> ~
I 114.0 0 8M
I 1 @ 2.5' Silty Sand: reddish-brown, dry, very
dense
109 5 2 111.0 5.6 @ 5' Silty Sand: reddish-brown, slightly moist, 08 I very dense
· ......
I
· ...... 3 @ 7.5' Silty Sand: reddish-brown, slightly
moist, dense
104 10 4 129.3 5.6 @ 10' Silty Sand: reddish-brown to gray-eN I brown, slightly moist, dense
I 5 @ 12.5' Silty fine Sand: reddish-brown to
8M medium-light brown, slightly moist, dense;
clear transition between red-brown sand and
99 15 6 120.2 4.0
medium-light brown sand
I @ 15' Silty Sand: reddish-brown, slightly moist,
medium dense
I 7 @ 17.5' Silty Sand: reddish-brown to brown,
· ...... slightly moist, dense · ...... · ......
94 20 8 115.8 9.1 @ 20' Silty Sand: reddish-brown to brown, I slightly moist to moist, very dense; gray
mottling
· ...... 9 I ....... @ 22.5' Silty Sand: light to moderate brown,
slightly moist to moist, dense to very dense;
reddish-brown mottling
89 25 I 10 @ 25' Silty Sand: reddish-brown, slightly moist
to moist
I 11 @ 27.5' Silty Sand: reddish-brown, slightly
moist to moist, very dense; gray-brown
mottling
I = Ring sample LAWSON & ASSOCIATES ~ = SPT sample
B-1 = Bulk sample GEOTECHNICAL CONSUL TIN.G, INC.
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I Geotechnical Boring Log LGC·3
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... --DESCRIPTION I "I-a> u ..0 0.. 0 --E ----..0 1i) .t:! 0> ..... >-~ --0 ::J C ..... ~ E a> c ---I Z ::J 'w >-I-0 .t:! ,2 a> 0 c a> CJ) ----() a> ... I ~ ..c ..c 0.. ::J CJ) 0 0 ..... > ...... 0.. E !i: en () a> 0.. e:! C:-'0 0.. a> a> co 0 CJ) ~ ill 0 CD CJ) CO 0 ::2: ::>
I 131.0 0 ....... SM . . . . . . .
@ 0' Silty Sand: reddish-brown, dry to slightly
moist
I 8-1 COR
I 126 5 1 33 113.3 4.9 @ 5' : Silty Sand: reddish-brown, moist, very 50/4" dense
I
I 121 10 2 17 @ 10' : Silty Sand: reddish-brown, slightly SHA 22
24 moist, dense to very dense
I
I 116 15 3 32 120.7 6.0 @ 15' : Silty Sand: reddish-brown and yellow, CN 50/5" slightly moist, to very dense · ...... · ...... · ...... · ...... I @ 20' : Silty Sand reddish-brown and black,
111 20 moist, very dense
I 4 26 SM 36
5 42
I @ 21.5' Silty Sand and Gravel: light brown
and red, slightly moist, dense; fragments of
well-rounded gravel in sampler; practical
106 25 refusal
I Notes:
-Total Depth = 21' 10" (Refusal)
I -Backfilled with bentonite chips
-No Groundwater Encountered
101 30
I • = Ring sample LAWSON & ASSOCIATES ~ = SPT sample
B-1 = Bulk sample GEOTECHNICAL CONSUL TING, INC.
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I Geotechnical Boring Log LGC·4
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I
..... ...-
I -Q) 0 .Q 0-(5 ...-E --...-.Q ...... EE.. 0) ...... £ :;:,g en 0 ::::I C e..-E Q) c ...-....J Z ::::I en >-I-...... 0 c Q) (/) 0 ::t:-o Q) 0 Q) ..... '0 I ~ :.c ::::I (/) ..c 0-0 ...... > ...... 0-E ~ en 0 Q) 0-ro ~ '0 0-Q) Q) ..... ro 0 (/) ~ w 0 <.9 (/) co 0 2 ~
I 131.0 0 8M
@ 0' Silty Sand: reddish-brown, dry to slightly
moist, loose
I
I 126 5 1 8 @ 5' Silty Sand: reddish-brown, slightly moist, 9
8 medium dense
I
I 121 10 2 7 110.8 5.3 @ 10' Silty Sand: brown to reddish-brown, eN 17
30 slightly moist, medium dense; visqueen found
in sampler
I
I 116 15 3 19 @ 15' Silty Sand: brown to reddish-brown, 22
27 slightly moist to moist, dense
I
111 20 Quaternarll Terrace deeosits {Qt}
I 4 50/6" 113.4 7.1 8M @ 20' Silty Sand: dark brown, black and red,
slightly moist, very dense
@ 23' Silty Sand with Gravel: light reddish-
I 35/3" brown to white, slightly moist, very dense;
refusal
I 106 25 Notes:
-Total Depth = 23' 3" (Auger Refusal)
-Backfilled with bentonite chips
I -No Groundwater Encountered
30
I = Ring sample LAWSON & ASSOCIATES ~ = SPT sample
B-1 = Bulk sample GEOTECHNICAL CONSULTING INC.
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I Geotechnical Boring Log LGC·5
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I '-ei=' Q) C,.) ..c ..3: a g 0> E ;g ..c ..... ..... ~ en a :::s c: ~ E Q) c: g ....J Z :::s ·00 >-I-a .g Q) a c: Q) en -'-I 1B .c .c 0. () Q) :::s en a ..... c.. E $: Cl 1i5 () Q) > c.. ct:l c-·0 c.. Q) Q) '-ct:l a en ~ ill Cl (!) en CCl Cl ::a: ::J
I 120.5 0 8M
@ 0' Silty Sand: reddish brown to yellow, dry to
I 8-1 slightly moist, loose to dense
I 116 5 1 9 @ 5' Silty Sand: reddish-brown, slightly MAX 15
22 moist,dense EI
I
111 10 Quaternar~ Terrace del20sits {Qt}
I 2 15 110.1 5.6 8M @ 10' Silty Sand: reddish-brown, slightly moist, 23
24 dense; red and orange mottling
I
I 106 15 3 @ 15' Silty Sand: reddish-brown to light brown
and white, slightly moist, very dense
I Notes:
-Total Depth = 16'
101 20 -Backfilled with bentonite chips
I -No Groundwater Encountered
I
I 95.5 25
I
I = Ring sample LAWSON & ASSOCIATES I8J = SPT sample
B-1 = Bulk sample GEOTECHNICAL CONSULTING INC.
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I Appendix C
I Laboratory Test Results
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APPEND/XC
T.aharata-q Testing Procedures and Test Results
The laboratory testing program was directed towards providing quantitative data relating to the relevant
engineering properties of the soils. Samples considered representative of site conditions were tested in
general accordance with American Society for Testing and Materials (ASTM) procedure and/or
California Test Methods (CTM), where applicable. The following summary is a brief outline of the test
type and a table summarizing the test results.
Moisture and Density Determination Tests: Moisture content (ASTM D2216) and dry density
determinations (ASTM D2937) were performed on relatively undisturbed samples obtained from the
test borings and/or trenches. The results of these tests are presented in the boring logs.
Expansion Index: The expansion potential of selected samples were evaluated by the Expansion Index
Test, D.B.C. Standard No. 18-2 and/or ASTM D4829. The results area as follows:
Sample Expansion Expansion
Location Index Potential*
II-I @ I-3ft 0 VeryLow
* Per Table 18-1-B of 1997 D.B.C.l2001 C.B.C.
Grain Size Distribution: Representative samples were dried, weighed, and soaked in water until
individual soil particles were separated (per ASTM D421) and then washed on a No. 200 sieve. The
portion retained on the No. 200 sieve was dried and then sieved on a U.S. Standard brass sieve set in
accordance with ASTM D422 (CTM 202). A hydrometer analysis was done to determine the
distribution of soil particles passing the No. 200 sieve on selected samples. Plots are provided in this
Appendix.
Maximum Density Tests: The maximum dry density and optimum moisture content of typical materials
were determined in accordance with ASTM D1557. The results of these tests are presented in the table
below:
Sample Sample Maximum Dry Optimum Moisture
Location Description Density (pcf) Content (%)
LGC-I Red-Brown Silty Sand 132.0 9.5
LGC-5 Red Slightly Clayey Silty Sand 133.0 8.0
Consolidation: Consolidation tests were performed on selected, relatively undisturbed ring samples
(Modified ASTM Test Method D2435). Samples (2.42 inches in diameter and 1 inch in height) were
placed in a consolidometer and increasing loads were applied. The samples were allowed to consolidate
under "double drainage" and total deformation for each loading step was recorded. The percent
consolidation for each load step was recorded as the ratio of the amount of vertical compression to the
original sample height. The consolidation pressure curves are presented in this Appendix.
Project No. 041065-02 Page C-1 February 25, 2005
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Direct Shear: Direct shear tests were performed on selected remolded and/or undisturbed samples,
which were soaked for a minimum of 24 hours under a surcharge equal to the applied normal force
during testing. The samples were tested under various normal loads, a motor-driven, strain-controlled,
direct-shear testing apparatus. The test plot is provided in this Appendix.
Soluble Sulfates: The soluble sulfate contents of selected samples were determined by standard
geochemical methods (CTM 417). The soluble sulfate content is used to determine the appropriate
cement type and maximum water-cement ratios. The test results are presented in the table below:
Sample Location Sulfate Content (% )* Sulfate Exposure**
LGC-3 @ 2-5 feet 0.01 Negligible
*Expressed as the percentage of water-soluble sulfate (S04) in soil, percentage by weight.
** Based on the 1997 edition of the Uniform Building Code (U.B.C.)/2001 C.B.C.,.Table No. 19-A-4
Minimum Resistiyjty and pH Tests: Minimum resistivity and pH tests were performed in general
accordance with CTM 643 and standard geochemical methods. The electrical resistivity of a soil is a
measure of its resistance to the flow of electrical current. As a results of soil's resistivity decreases
corrosivity increases. The results are presented in the table below:
Sample Location pH Minimum Resistivity (ohms-em)
LGC-3 @ 2-5 feet 6.1 6,140
Chloride Content: Chloride content was tested in accordance with Caltrans Test Method (CTM) 422.
The results are presented below:
Sample Location Chloride Content, ppm
LGC-3 @ 2-5 feet 53
Project No. 041065-02 Page C-2 February 25,2005
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Location
Molding
Sample No. Depth (ft) Moisture
Content (%)
1 1-3 9.0
I 1997 U.B.C. /2001 C.B.C. Table 18-I-B
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EXPANSION INDEX
(ASTM D 4829)
Initial Dry
Density (pef)
113.3
Final Expansion Moisture Index Content (%)
12.6 0
Project Number:
Date:
Expansion
Classification 1
Very Low
041065-02
Feb-05
Paseo Del Norte I Carlsbad
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100
90
80
-70 .c C) 'Q)
3: 60
>-III
~ 50 (1) c u: -40 c
(1)
() ~ (1) a. 30
20
10
0
100
GRAVEL SAND
Boring
No.:
LGC-2
-
10
Sample Depth
No.: (ft.)
3 12.5
"'
\
\
o l!)
*
\
~~
\
o o
*
1\-
"
0.1
Particle Size (mm)
Soil Gravel
Type (%)
SM 0
Sample Description: Silty Sand
PARTICLE SIZE ANALYSIS
(ASTM D 422)
...,~
FINES (SILT AND CLAY)
~'-.... -...
~I'--~~
0.01
Sand Fines
(%) (%)
77 23
Project Number:
Date:
0.001
041065-01
Jul-04
Paseo Del Norte I Carlsbad
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100
90
80
-70 .c
C)
'iii 3: 60
>-III
"-50 Q) c
i.i: -40 c Q)
(,) "-Q)
C. 30
20
10
0
GRAVEL SAND
~
Co ..... .....
100
Boring
No.:
LG,C-3
~ Co ?i ...... C')
10
Sample Depth
No.: (ft.)
3 10
co .....
"'
\
1\
o LO
'*I:
\
~\
\
1\
o o .....
"
0.1
Particle Size (mm)
Soil Gravel
Type (%)
SM 0
Sample Description: Silty Sand
PARTICLE SIZE ANALYSIS
(ASTM D 422)
o o C\J
'*I:
FINES (SILT AND CLAY)
~~. ...... ~ ~~ ~
~
0.01
Sand Fines
(%) (%)
71 29
Project Number:
Date:
-+
0.001
041065-01
Jul-04
Paseo Del Norte I Carlsbad
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-eft. -c 0 += CIS E ... 0 -CI)
C
-1.0 -l---_+-_+----jl--Hr-+-H-l----+--t-r--t-H-!-t+--J
1.0
2.0
3.0
4.0
___ Inundated
-9-Field Moisture
5.0-l---~-_+-~~~_H~--_4-_4-+-+-~~++----~-~~~-~T+_r1
7.0-l-----+---+-+-4-+-~~-----4_--4_~-~r+4_rr---r_--r__r_+_r~Hr!
8.0L-___ ~ __ ~ __ J_-L~LJ~L_ ____ -L __ ~~L_L_~_L~ _____ L_ __ ~_L~_L~~
0.1
Boring No.: Sample No.:
LGC-1 5
Vertical Stress (ksf) 10
Initial Final
Depth (tt) Moisture Moisture Dry Density
(pef) Content ('Yo) Content ('Yo)
12.5 121.0 6.1 14.0
100
LGC ONE-DIMENSIONAL CONSOLIDATION
Project Number: 041065-01
Date: Jul-04
Paseo Del Norte I Carlsbad
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-2.0
0.0
2.0
-~ 0 -c 0 :a 4.0
E ... 0 'm c
6.0
B.O
10.0
0.1
____ Inundated
-e-Field Moisture
~ i'---~ ~ "'~ "-~
"-" '\ " 1\\
10 100
Vertical Stress (ksf)
Dry Density Initial Final
Boring No.: Sample No.: Depth (tt) Moisture Moisture (pef) Content (%) Content (%)
LGC-2 6 10 120.2 4.0 17.8
Project Number: 041065-01
ONE-DIMENSIONAL CONSOLIDATION Date: Jul-04
Paseo Del Norte I Carlsbad
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-2.0
0.0
2.0
-#. -c 0 ~ 4.0
E ... 0 -Q)
C
6.0
8.0
10.0
0.1
-'-Inundated
-e-Field Moisture
e-----E ~ -.. ~~
~ ......... ~ ......... ........
10 Vertical Stress (ksf)
Boring No.: Sample No.: Depth (tt)
LGC-3 3 15
Dry Density
(pef)
120.7
ONE-DIMENSIONAL CONSOLIDATION
Initial Final
Moisture Moisture
Content (%) Content (%)
6.0 13.8
Project Number:
Date:
065-01
1-04
Paseo Del Norte I Carlsbad
100
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-(f!. -c 0 :;:: ca E ... 0 -CI)
C
0.0
2.0
4.0
6.0
B.O
10.0
12.0
0.1
II ~ 0 ..... -'-Inundated
""-I'\1t -a-Field Moisture
\
'\
\
\
\
\ .... \
~ 4,
Vertical Stress (ksf) 10
Dry Density
Boring No.: Sample No.: Depth (ft) (pet)
LGC-4 5 10 110.8
ONE-DIMENSIONAL CONSOLIDATION
Initial Final
Moisture Moisture
Content (%) Content (%)
5.3 12.3
Project Number:
Date:
041065-01
Jul-04
Paseo Del Norte I Carlsbad
100
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3.0
~Peak o Deformation at 1/4" I
I Friction Angle = 30.ao Friction Angle = 32.10 J
Cohesion (psf) = 215 Cohesion (pst) = 60
2.0
--~ -I/)
I/)
G) 10.. -en
10.. cu G) ..c: en
1.0 ./
~'
~ ~
;:? V
0.0
0.0
Boring No.:
LGC-2
LGC
1.0 2.0
Normal Stress (ksf)
Shear Rate Dry Density Initial Final
Sample No.: Depth (tt) Sample Type Moisture Moisture (inch/min)
2 5 Driven 0.05
Sample Description: Reddish Brown Sand
DIRECT, SHEAR PLOT
(pct) Content (%) Content (%)
111.0 5.6 15.3
Project Number: 041065-01
Date: Ju/-04
Paseo Del Norte I Carlsbad
3.0
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SOIL RESISTIVITY TEST
DOT CA TEST 532 I 643
Project Name: Paseo Del Norte ~~~~~~-----------------Tested By : V]
Data Input By: LF
Date: 07/21/04
Date: 07/23/04 Project No. : 041065-01
Boring No.: =-LG=--C=---=-3 __ _ Depth (ft.) : ..;....:N!..-'-/A-'--__ _
Sample No. : 8-1 -----------
Soil Identification: SM -----------
Water Adjusted
Specimen Added (ml) Moisture
No. Content (Wa) (MC)
1 100 13.45
2 200 21.55
3 300 29.65
4
5
Min. Resistivity I Moisture Content
(ohm-cm) I (%)
DOT CA Test 532 / 643
Resistance Soil
Reading Resistivity
(ohm) (ohm-cm)
980 6611
910 6139
970 6544
Sulfate Content
(ppm)
DOT CA Test 417 Part II
Moisture Content (%) (MCi) 5.34
Wet Wt. of Soil + Cont. (g) 213.78
Dry Wt. of Soil + Cont. (gl 205.91
wt. of Container (gl 58.62
Container No.
Initial Soil Wt. (g) (Wt) 1300.00
Box Constant p.746
MC =(((1 + Mci/l00)x(Wa/Wt+ 1))-1)xl00
Chloride Content
(ppm)
DOT CA Test 422
Soil pH
pH I Temp. C°C)
DOT CA Test 532 / 643
'.~';:-:3:::!=::=C:=:~:'-~::-:':= -; 7,-;:-~7:'-:-;:-.'";-~~~·~:-=.l =:;:=:;~3~'~~'--::''''-'1:?-::';;rC:;--:IJ ,;,,·~wL!'~p::'f2r;..::2.."5~-r'iF1i~~lfj;mt1.I'.dlJiPE;'~';~i';p:, ic~f. 'fh ~;Vti';'·''::'!.s'I~l'i.li:~1M7ta~.;.[t~
6140 I 21.5 I 96 I 53 I 6.10 I 21.0
6700
6600
-E <r 6500
E .J:: o -~ 6400
> :p
.!Q
U)
Q) 0::: 6300
'0 en
6200 -
6100
10.0
I I U
\1
\
\
1
I 1\
\
\
1 -1\
I I I I
1 1
1
15.0
1
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--/
L
/
/
/
\ -\
\
\
I L
1\ .I
\
/
'\ /
'\. /
l"-. /
"-~ ./ -
20.0 25.0 30.0
Moisture Content (%)
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I AppendixD
I Seismic Analyses
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APPENDIXD
SEISIMIC ANALYSIS
A probabilistic seismic analysis utilizing the computer program FRISKSP (Blake, 2000) was performed to
evaluate the anticipated ground motion at the subject site. The results of the analysis are discussed in terms
of the 'Design Basis Earthquake' ground motion or PGADBE, which is defined as the estimated peak ground
acceleration that has a 10 percent probability of exceedance over a 50 year span. Based on the results of the
analysis, the estimated PGADBE at the subject site is approximately 0.27 g.
Site coordinates of latitude 33.1031 degrees north and longitude 117.3088 degrees west, which are
representative of the of the site, were utilized for the following FRISKSP analysis.
Attenuation PGADBE PGAUBE
Boore et al. (1997) NEHRP D O.31g 0.40g
Bozorgnia, Campbell & Niazi (1999) PS O.29g 0.41g
Campbell & Bozorgnia (1997 rev.) AL O.23g 0.33g
Sadigh et al. (1997) Deep Soil O.2Sg 0.33g
AVERAGE O.27g 0.37g
Notes:
• The 10% probability of exceedance during a 50-year exposure period (475-year return) corresponds to
the UBC/CBC Design Basis Earthquake peak ground acceleration (PGADBE).
• The 10% probability of exceedance during a 100-year exposure period (949-year return) corresponds to
the UBC/CBC Upper Bound Earthquake peak ground acceleration (PGAUBE).
, !
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..-..
~
'-'"
~
:t::! -.-..0 co
..0
0 L-a..
Q) u c: co
"0
Q)
Q) u >< LU
PROBABILITY OF EXCEEDANCE
BOORE ET AL(1997) NEHRP D (250)1
100
90
80
70
60
50
40
30
20
10
0
~
~
§\
l-
I-
l-
I-
----
I-l-
I-
I-
----
-
l-
I--
--
l-
I-
I-
I-
,
\\
4\\
\ \
\
I • I 25 yrs
I • I
75 yrs
\
~
~ ~ =, , , , , , T .L I 11
I .. I
50 yrs
I • I
100 yrs
1 1 I 1 1 I 1 I ,
0.00 0.25 0.50 0.75 1.00 1.25 1.50 , ..
Acceleration (Q)
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..-.
?fl.
'-"
~ .f-I .--.-..c co ..c
0 S-o..
(J)
(.)
c co
"'C
(J)
(J)
(.) x LU
PROBABILITY OF EXCEEDANCE
BOZ. ET AL.(1999)HORPS UNe 1
100 c-
90
80
r-r-
70 r-
---
60 -
l-
I-
I-
50 ,..-
--
l-
40 I-
l-I-
"-
30 ,.-
---
20 -
I-
l-
i-
10 i-
--
0 '=,
~
~V
\ ,
1
\ ~
\~
l\
........
, , ,
\
I • I 25 yrs
I • I 75 yrs
~
~ ~
, , I --I .L I
I
I .A I
50 yrs
I T I
100 vrs
I 1 I 1 1 III I
0.00 0.25 0.50 0.75 1.00 1.25 1.50
Acceleration (Q)
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.-..
?fl.
"-"
~ ......., .--.-..c co ..c
0 ~ c..
Q)
0 c co
"C
Q)
Q)
0 x UJ
PROBABILITY OF EXCEEDANCE
CAMP. & BOZ. (1997 Rev.) AL 1
100 ..
:-,...
90
80
70 ---
60 f-
f-
I-'--
50 -
--
f-
40 I-
'----
30 -
I-
I-
l-
20 i-
---
10 -
I-
f-
0 ~I
~
\\
\\\
\~ ~
\~
" I I I
I • I
25 yrs
I • I
75 yrs
~
~
I
I ..L 1 I 1 I
I .. I
. 50 yrs
I ~ I
100 Irs . ~
I 1 I 1 1 I 1 I I
0.00 0.25 0.50 0.75 1.00 1.25 1.50
Acceleration (Q)
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..-..
?f2.
'-""
~ ~ -.-.0 co
.0
0 L-a..
(J)
t) c co -c
(J)
(J)
t)
>< UJ
PROBABILITY OF EXCEEDANCE
SADIGH ET AL. (1997) DEEP SOIL 1
100 .....
90
80
70
~
~ \\'
l-
I-
I--
60 l-
I-
l-
I-
50 l-
I--
40
30
20
10
I--\ I--
l-
I--
• \1 '----
-\~~ --I--
I--\~ '--,......
-
-"--
0 ~I I I I
I • I
25 yrs
I • I 75 yrs
~
~~ I 1 1 I 11
I ... I
50 yrs
I T I
100 yrs
I 1 I 1 1 III I
0.00 0.25 0.50 0.75 1.00 1.25 1.50 . , ~ -
Acceleration (Q)
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AppendixE
General Earthwork & Grading Specification for Rough Grading
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1.0
LA WSON & ASSOCIATES GEOTECHNICAL CONSULTING, INC.
General Earthwork and Grading Specifications fi'ar Rough Grading
General
1.1
1.2
h.J.tJm1.: These General Earthwork and Grading Specifications are for the grading and
earthwork shown on the approved grading planes) and/or indicated in the geotechnical
report(s). These Specifications are a part of the recommendations contained in the
geotechnical report(s). In case of conflict, the specific recommendations in the
geotechnical report shall supersede these more general Specifications. Observations of
the earthwork by the project Geotechnical Consultant during the course of grading may
result in new or revised recommendations that could supersede these specifications or
the recommendations in the geotechnical report(s).
The Geotechnical Consultant oJ Record: Prior to commencement of work, the owner
shall employ a qualified Geotechnical Consultant of Record (Geotechnical Consultant).
The Geotechnical Consultant shall be responsible for reviewing the approved
geotechnical report(s) and accepting the adequacy of the preliminary geotechnical
findings, conclusions, and recommendations prior to the commencement of the grading.
Prior to commencement of grading, the Geotechnical Consultant shall review the "work'
plan" prepared by the Earthwork Contractor (Contractor) and schedule sufficient
personnel to perform the appropriate level of observation, mapping, and compaction
testing.
During the grading and earthwork operations, the Geotechnical Consultant shall
observe, map, and document the subsurface exposures to verify the geotechnical design
assumptions. If the observed conditions are found to be significantly different than the
interpreted assumptions during the design phase, the Geotechnical Consultant shall
inform the owner, recommend appropriate changes in design to accommodate the
observed conditions, and notify the review agency where required.
The Geotechnical Consultant shall observe the moisture-conditioning and processing of
the subgrade and fill materials and perform relative compaction testing of fill to
confirm that the attained level of compaction is being accomplished as specified. The
Geotechnical Consultant shall provide the test results to the owner and the Contractor
on a routine and frequent basis.
1.3 The Earthwork Contractor: The Earthwork Contractor (Contractor) shall be qualified,
experienced, and knowledgeable in earthwork logistics, preparation and processing of
ground to receive fill, moisture-conditioning and processing of fill, and compacting fill.
The Contractor shall r~view and accept the pl~n~, geotechnical report(s), and these
Specifications prior to commencement of grading. The Contractor shall be solely
responsible for performing the grading in accordance with the project plans and
Lawson & Associates Geotechnical Consulting, Inc.
General Earthwork and Grading Specifications
Pagelof6
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2.0
specifications. The Contractor shall prepare and submit to the owner and the
Geotechnical Consultant a work plan that indicates the sequence of earthwork grading,
the number of "equipment" of work and the estimated quantities of daily earthwork
contemplated for the site prior to commencement of grading. The Contractor shall
inform the owner and the Geotechnical Consultant of changes in work schedules and
updates to the work plan at least 24 hours in advance of such changes so that
appropriate personnel will be available for observation and testing.. The Contractor
shall not assume that the Geotechnical Consultant is aware of all grading operations.
The Contractor shall have the sole responsibility to provide adequate equipment and
methods to accomplish the earthwork in accordance with the applicable grading codes
and agency ordinances, these Specifications, and the recommendations in the approved
geotechnical report(s) and grading planes). If, in the opinion of the Geotechnical
Consultant, unsatisfactory conditions, such as unsuitable soil, improper moisture
condition, inadequate compaction, insufficient buttress key size, adverse weather, etc.,
are resulting in a quality of work less than required in these specifications, the
Geotechnical Consultant shall reject the work and may recommend to the owner that
construction be stopped until the conditions are rectified. It is the contractor's sole
responsibility to provide proper fill compaction.
Preparation afA reas to he FiIled
2.1 Clearing and Grubbing: Vegetation, such as brush, grass, roots, and other deleterious
material shall be sufficiently removed and properly disposed of in a method acceptable
to the owner, governing agencies, and the Geotechnical Consultant.
The Geotechnical Consultant shall evaluate the extent of these removals depending on
specific site conditions. Earth fill material shall not contain more than 1 percent of
organic materials (by volume). No fill lift shall contain more than 10 percent of organic
matter. Nesting of the organic materials shall not be allowed. '
If potentially hazardous materials are encountered, the Contractor shall stop work in the
affected area, and a hazardous material specialist shall be informed immediately for
proper evaluation and handling of these materials prior to continuing to work in that
area.
As presently defined by the State of California, most refined petroleum products
(gasoline, diesel fuel, motor oil, grease, coolant, etc.) have chemical constituents that
are considered to be hazardous waste. As such, the indiscriminate dumping or spillage
of these fluids onto the ground may constitute a misdemeanor, punishable by fines
and/or imprisonment, and shall not be allowed. The contractor is responsible for all
hazardous waste relating to his work. The Geotechnical Consultant does not have
expertise in this area. If ha~ardous waste is a COnCyffi, then the Client should acquire the
services of a qualified environmental assessor.
Lawson & Associates Geotechnical Consulting, Inc.
General Earthwork and Grading Specifications
Page 2 of6
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3.0
2.2 Processing: Existing ground that has been declared satisfactory for support of fill by
the Geotechnical Consultant shall be scarified to a minimum depth of 6 inches.
Existing ground that is not satisfactory shall be overexcavated as specified in the
following section. Scarification shall continue until soils are broken down and free of
oversize material and the working surface is reasonably uniform, flat, and free of
uneven features that would inhibit uniform compaction.
2.3 Overexcavatian: In addition to removals and overexcavations recommended in the
approved geotechnical report(s) and the grading plan, soft, loose, dry, saturated,
spongy, organic-rich, highly fractured or otherwise unsuitable ground shall be
overexcavated to competent ground as evaluated by the Geotechnical Consultant during
grading.
2.4 Benching: Where fills are to be placed on ground with slopes steeper than 5:1
(horizontal to vertical units), the ground shall be stepped or benched. Please see the
Standard Details for a graphic illustration. The lowest bench or key shall be a
minimum of 15 feet wide and at least 2 feet deep, into competent material as evaluated
by the Geotechnical Consultant. Other benches shall be excavated a minimum height
of 4 feet into competent material or as otherwise recommended by the Geotechnical
Consultant. Fill placed on ground sloping flatter than 5:1 shall also be benched or
otherwise overexcavated to provide a flat sub grade for the fill.
2.5 Evaluatian/Acceptance of Fill Areas: All areas.to receive-fill, including removal and.
processed areas, key bottoms, and benches, shall be observed, mapped, elevations
recorded, and/or tested prior to being accepted by the Geotechnical Consultant as
suitable to receive fill. The Contractor shall obtain a written acceptance from the
Geotechnical Consultant prior to fill placement. A licensed surveyor shall provide the
survey control for determining elevations of processed areas, keys, and benches.
Fill MaterinJ
3.1 General: Material to be used as fill shall be essentially free of organic matter and other
deleterious substances evaluated and accepted by the Geotechnical Consultant prior to
placement. Soils of poor quality, such as those with unacceptable gradation, high
expansion potential, or low strength shall be placed in areas acceptable to the
Geotechnical Consultant or mixed with other soils to achieve satisfactory fill material.
3.2 Oversize: Oversize material defined as rock, or other irreducible material with a
maximum dimension greater than 8 inches, shall not be buried or placed in fill unless
location, materials, and placement methods are specifically accepted by the
Geotechnical Consultant (see Oversize Rock Disposal Figure). Placement operations
shall be such that nesting of oversized material does not occur and such that oversize
material is completely ~un:ounded by compacted or densified fill.
Lawson & Associates Geotechnical Consulting, Inc.
General Earthwork and Grading Specifications
Page 3 0/6
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4.0
3.3 Impart: If importing of fill material is required for grading, proposed import material
shall meet the requirements of Section 3.1. The potential import source shall be given
to the Geotechnical Consultant at least 48 hours (2 working days) before importing
begins so that its suitability can be determined and appropriate tests performed.
Fill Placement and Compaction
4.1 FillW;yers: Approved fill material shall be placed in areas prepared to receive fill (per
Section 3.0) in near-horizontal layers not exceeding 8 inches in loose thickness. The
Geotechnical Consultant may accept thicker layers if testing indicates the grading
procedures can adequately compact the thicker layers. Each layer shall be spread
evenly and mixed thoroughly to attain relative uniformity of material and moisture
throughout.
4.2 Fill MQisture Conditioning· Fill soils shall be watered, dried back, blended, and/or
mixed, as necessary to attain a relatively uniform moisture content at or slightly over
optimum. Maximum density and optimum soil moisture content tests shall be
performed in accordance with the American Society of Testing and Materials (ASTM
Test Method DI557).
4.3 CQm .... naction at Fill: After each layer has been moisture-conditioned, mixed, and
evenly spread, it shall be uniformly compacted to not less than 90 percent of maximum
dry density (ASTM Test Method DI557). Compaction equipment shall be adequately
sized and be either specifically designed for soil compaction or of proven reliability to
efficiently achieve the specified level of compaction with uniformity.
4.4 Compaction of Fill Slopes: In addition to normal compaction procedures specified
above, compaction of slopes shall be accomplished by backrolling of slopes with
sheepsfoot rollers at increments of 3 to 4 feet in fill elevation, or by other methods
producing satisfactory results acceptable to the Geotechnical Consultant. Upon
completion of grading, relative compaction of the fill, out to the slope face, shall be at
least 90 percent of maximum density per ASTM Test Method D 1557.
4.5 Compaction Testing: Field tests for moisture content and relative compaction of the
fill soils shall be performed by the Geotechnical Consultant. Location and frequency of
tests shall be at the Consultant's discretion based on field conditions encountered.
Compaction test locations will not necessarily be selected on a random basis. Test
locations shall be selected to verify adequacy of compaction levels in areas that are
judged to be prone to inadequate compaction (such as close to slope faces and at the
fill/bedrock benches).
A representative of the Geotechnical Consultant should be onsite continuously to
observe rock fill placeWffnt. Evaluation of rock fills should be based on observation of
the placement operations, nuclear gauge testing in areas of sufficient fines, and
observation of frequent test pits.
Lawson & Associates Geotechnical Consulting, Inc.
General Earthwork and Grading Specifications
Page4of6
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5.0
6.0
7.0
4.6
4.7
Frequency of Compaction Testing: Tests shall be taken at intervals not exceeding
2 feet in vertical rise and/or 1,000 cubic yards of compacted fill soils embankment. In
addition, as a guideline, at least one test shall be taken on slope faces for each
5,000 square feet of slope face and/or each 10 feet of vertical height of slope. The
Contractor shall assure that fill construction is such that the testing schedule can be
accomplished by the Geotechnical Consultant. The Contractor shall stop or slow down
the earthwork construction if these minimum standards are not met.
Cawnaction Test Locations: The Geotechnical Consultant shall document the J..
approximate elevation and horizontal coordinates of each test location. The Contractor
shall coordinate with the project surveyor to assure that sufficient grade stakes are
established so that the Geotechnical Consultant can determine the test locations with
sufficient accuracy. At a minimum, two grade stakes within a horizontal distance of
100 feet and vertically less than 5 feet apart from potential test locations shall be
provided.
Suhdrain [n,gallation
Subdrain systems shall be installed in accordance with the approved geotechnical report(s), the
grading plan, and the Standard Details. The Geotechnical Consultant may recommend
additional subdrains and/or changes in sub drain extent, location, grade, or material depending
on conditions encountered during grading. All subdrains shall b~ surveyed by a land
surveyor/civil engineer for line and grade after installation and prior to burial. Sufficient time
should be allowed by the Contractor for these surveys.
Excavation
Excavations, as well as over-excavation for remedial purposes, shall be evaluated by the
Geotechnical Consultant during grading. Remedial removal depths shown on geotechnical
plans are estimates only. The actual extent of removal shall be determined by the Geotechnical
Consultant based on the field evaluation of exposed conditions during grading. Where
fill-over-cut slopes are to be graded, the cut portion of the slope shall be made, evaluated, and
accepted by the Geotechnical Consultant prior to placement of materials for construction of the
fill portion of the slope, unless otherwise recommended by the Geotechnical Consultant.
Trench Backfills
7.1 The Contractor shall follow all OHSA and CallOSHA requirements for safety of trench
excavations.
Lawson & Associates Geotechnical Consulting, Inc.
General Earthwork and Grading Specifications
PageS 0/6
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7.2
7.3
7.4
7.5
All bedding and backfill of utility trenches shall be done in accordance with the
applicable provisions of Standard Specifications of Public Works Construction.
Bedding material shall have a Sand Equivalent greater than 30 (SE>30). The bedding
shall be placed to I foot over the top of the conduit and densified by jetting. Backfill
shall be placed and densified to a minimum of 90 percent of maximum from 1 foot
above the top of the conduit to the surface.
The jetting of the bedding around the conduits shall be observed by the Geotechnical
Consultant.
The Geotechnical Consultant shall test the trench backfill for relative compaction. At
least one test should be made for every 300 feet of trench and 2 feet of fill.
Lift thickness of trench backfill shall not exceed those allowed in the Standard
Specifications of Public Works Construction unless the Contractor can demonstrate to
the Geotechnical Consultant that the fill lift can be compacted to the minimum relative
compaction by his alternative equipment and method.
Lawson & Associates Geotechnical Consulting, Inc.
General Earthwork and Grading Specifications
Page 6 0/6
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Cut Lot
(Exposing Unsuitable Soils at Design Grade)
Remove Unsuitable
1:1 Projection To
Competent Material
Material
1:1 Projection To Competent Material
Competent Material Overexcavate and Recompact
Note 1: Removal Bottom Should be Graded Note 2: Where Design Cut Lots are
With Minimum 2 % Fa" Towards Street or Excavated Entirely Into Competent
Other Suitable Area (as Determined by Material, Overexcavation May Still be
Soils Engineer) to Avoid Ponding Below Required for Hard-Rock Conditions or for
Building Materials With Variable Expansion
Characteristics.
Cut/Fill Transition Lot
----
-,t
5 Min. ~
---1:1 Projection To
Competent Material -----:;itfl~~~;~,~i~$%~;~~~~:,m~~~~;jj~~Ji*l~::~:~iWJ}~;i~il;fi;L, l::::~)::';" 5Jn.
,:'., ..... ~.:.'.: .. '.: :' .::.:.1..,;" .. 'u«-o~ '.,:' ... '.: .,' ,.' ': ~.;.,,·1~::-·: Overexcavate ~1~~it~~t~~~~:::.ri~~:;?;~;":' i:' ~~ro~ ~il~~;~~::r~~:~lR(:,:pact
*Deeper if Specified by
Soils Engineer
LGC CUT AND TRANSITION
LOT OVEREXCA V ATION
DETAIL . ,
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Fill Slope
1:1 Projection To
Competent Material
Fill-Over-Cut Slope
Cut-Over-Fill Slope
LGC
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15' Min. Key Width * Construct Cut Slope First
''''''+--Compacted Fill
Competent Material
Note: Natural Slopes Steeper Than 5:1 (H:V)
Must Be Benched.
KEYING AND BENCHING
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Deeper in Areas of
Swimming Pools, Etc.
Slope Face
Windrow Parallel to Slope Face
Jetted or Flooded Approved
Granular Material
Excavated Trench
or Dozer V-cut
Note: Oversize Rock is Larger
than 8" in Maximum Dimension. Section A-A I
OVERSIZE ROCK
DISPOSAL DETAIL
Compacted
Fill
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1-.
Proposed Grade
\
\
5' Typical Compacted Fill
if Recommended by Soils Engineer
(30' Max.)
Competent Material
2:1 (H:V) Back Cut or as
Designed by Soils Engineer
'"
4' Typical
Key Dimensions Per Soils Engineer \ Greater of 2% Slope
~r l' Tilt Back
~---'"
Perf. PVC Pipe \
Perforations Down -----------... \
12" Min. Overlap,
Secured Everty 6 Feet ----'-1--/
Sched. 40 Solid PVC Outlet Pipe, (Backfilled ---1--0""-
and Compacted With Native Materials) \.1 ---~[P.
Outlets to be Placed Every 100' (Max.) O.C.
5 Ft.JFt. 3/4" -1 1/2" Open Graded Rock ----~----./
Geofabric (Mirafi 140N ---------"------or Approved Equivalent)
LGC TYPICAL BUTTRESS
DETAIL
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I-15' Min.-l
\
\
\
5' Typical Compacted Fill
if Recommended by Soils Engineer
(30' Max.)
Competent Material
"" 2:1 (H:V) Back Cut or as
"" Designed by Soils Engineer
""
Key Dimensions Per Soils
Engineer (Typically H/2 or 15' Min) '-----'\l-Greater of 2% Slope
\ or 1 foot Tilt Bac ----""
Perf. PVC Pipe \
Perforations Down ---------......
\
12" Min. Overlap,
Secured Every 6 Feet ---I--/-../
Sched. 40 Solid PVC Outlet Pipe, (Backfilled
and Compacted With Native Materials) ---I--~_--fft:rJ ~~~~~
Outlets to be Placed Every 100' (Max.) O.C.
!fFt./Ft. 3/4" -11/2" Open Graded Rock ---:..-----"
Geofabric (Mirafi 140N ---------......... ----or Approved Equivalent)
LGC TYPICAL STABILIZATION
FILL DETAIL
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Natural Ground
Proposed Grade ~
Notes:
1) Continuous Runs in Excess of 500'
Shall Use 8" Diameter Pipe.
2) Final 20' of Pipe at Outlet Shall be
Solid and Backfilled with Fine-grained
Material.
12" Min. Overlap, _'\~--1
Secured Every 6 Feet '\
6" Collector Pipe
(Sched. 40, Perf. PVC)
3/4" - 1
Remove Unsuitable
Materials
Geofabric (Mirafi 140N
or Approved Equivalent)
Proposed Outlet Detail
Proposed Grade
LGC
11/26/02
May be Deeper Dependent
upon Site Conditions
6" Perforated PVC Schedule 40
Geofabric (Mirafi 140N
or Approved Equivalent)
CANYON SUB DRAINS