HomeMy WebLinkAboutCT 05-15; La Costa Oaks Neigh 3.3; Update Geotechnical Report-La Costa Oaks N 3.3 North; 2008-05-07GE
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UPDATE
GEOTECHNICAL REPORT
VILLAGES OF LA COSTA -
THE OAKS NORTH
NEIGHBORHOOD 3.3 NORTH
LOTS 1 THROUGH 18,
LOTS 36 THROUGH 79, AND
LOTS 116 THOROUGH 120
CARLSBAD, CALIFORNIA
PREPARED FOR
SAN DIEGO NORTH COUNTY
NEW HOMES COMMUNITIES
c/o EPPSTEINER & ASSOCIATES
SOLANA BEACH, CALIFORNIA
MAY 7, 2008
PROJECT NO. 06105-52-24
9
J
GEOCON
INCORPORATED
GEOTECHNICAL CONSULTANTS
Project No. 06105-52-24
May 7, 2008
San Diego North County New Homes Communities
c/o Eppsteiner & Associates
201 Lomas Santa Fe, Suite 460
Solana Beach, California 92075
Attention: Mr. Stuart M. Eppsteiner
Subject: VILLAGES OF LA COSTA - THE OAKS NORTH
NEIGHBORHOOD 3.3 NORTH
LOTS 1 THROUGH 18, 36 THROUGH 79, AND 116 THROUGH 120
CARLSBAD, CALIFORNIA
UPDATE GEOTECHNICAL REPORT
Dear Mr. Eppsteiner:
In accordance with your request and our proposal (LG-08130) dated April 23, 2008, we have prepared
this update geotechnical report for the subject project. The accompanying report presents the results of
our study and conclusions and recommendations pertaining to the geotechnical aspects of proposed
development of the site.
The site was graded as part of the Villages of La Costa - Oaks North development. The grading for this
neighborhood was completed in September 2007. Compacted fill and formational materials of Santiago
Peak Volcanics and Escondido Creek Granodiorite underlie the site. Provided the recommendations
contained in this update report are followed, the site is considered suitable for construction and support
of the proposed residential structures.
Should you have questions regarding this report, or if we may be of further service, please contact the
undersigned at your convenience.
GEOCON INCORPORATED
Michael C. Ertwine
Senior Staff Geologist
MCE:AS:SW:dmc
(6/del) Addressee
(e-mail) Colrich
Attention: Mr. Steve Butler
Sadr
CEG 1778
Shawn Weedon
GE2714
6960 Flanders Drive • San Diego, California 92121-2974 • Telephone (858) 558-6900 • Fax (858) 55&6159
TABLE OF CONTENTS
1. PURPOSE AND SCOPE 1
2. SITE AND PROJECT DESCRIPTION 1
3. PREVIOUS SITE DEVELOPMENT 2
4. SOIL AND GEOLOGIC CONDITIONS 2
4.1 Compacted Fill 2
4.2 Santiago Peak Volcanics (Jsp) 3
4.3 Escondido Creek Granodiorite (Ke) 3
5. GROUNDWATER 3
6. GEOLOGIC HAZARDS 3
6.1 Faulting and Seismicity 3
6.2 Liquefaction 4
7. CONCLUSIONS AND RECOMMENDATIONS 5
7.1 General 5
7.2 Finish Grade Soil Conditions 5
7.3 Seismic Design Criteria 6
7.4 Future Grading 7
7.5 Foundation and Concrete Slabs-On-Grade Recommendations 8
7.6 Retaining Walls and Lateral Loads 12
7.7 Slope Maintenance 13
7.8 Site Drainage 14
7.9 Foundation Plan Review 14
LIMITATIONS AND UNIFORMITY OF CONDITIONS
FIGURES
1. Vicinity Map
2. Wall/Column Footing Dimension Detail
3. Typical Retaining Wall Drain Detail
TABLES
I. Summary of As-Graded Building Pad Conditions and Recommended Foundation Categories
II. Summary of Laboratory Expansion Index Test Results
III. Summary of Finish Grade Expansion Index Test Results
IV. Summary of Laboratory Water-Soluble Sulfate Content Test Results
V. Summary of Soil Profile Type
UPDATE GEOTECHNICAL REPORT
1. PURPOSE AND SCOPE
This report presents the results of the update geotechnical study for Lots 1 through 18, 36 through 79
and 116 through 120 located at the Villages of La Costa - The Oaks North, Neighborhood 3.3 - North.
The purpose of this update report is to provide information regarding the geologic conditions
underlying the site and to provide foundation and retaining wall design recommendations.
The scope of the study included a review of the following:
1. Update Geotechnical Investigation, Villages of La Costa-The Oaks, Carlsbad, California,
prepared by Geocon Incorporated, dated August 3, 2001 (Project No. 06105-12-04).
2. Final Report of Testing and Observation Services Performed During Site Grading, Villages of
La Costa - The Oaks North, Neighborhood 3.3 - North, Lots 1 through 18, Lots 36 through 79
and Lots 116 through 120, Carlsbad, California, prepared by Geocon Incorporated, dated
November 14, 2007 (Project No. 06105-52-20).
3. Rough Grading and Erosion Control Plans for La Costa Oaks North Neighborhood 3.3 North
Drawing No. 446-5A, City of Carlsbad approval date July 12, 2007
2. SITE AND PROJECT DESCRIPTION
The subject lots are within the Villages of La Costa - The Oaks North, Neighborhood 3.3 - North
development located within the east central portion of the Oaks- North project, just east of the
intersection of Rancho Santa Fe Road and Avenida Soledad in the City of Carlsbad, California (see
Vicinity Map, Figure 1). Proposed development includes the construction of 67 single-family
residential homes and associated improvements.
Compacted fill is exposed at grade and is underlain by volcanic rock of Santiago Peak Volcanics and
granitic rock of Escondido Creek Granodiorite. A summary of the as-graded pad conditions for each lot
is provided on Table I. In general, the on-site fill materials vary between angular gravels and boulders
produced by on-site blasting of hard rock and silty, fine to coarse sand and sandy clay derived from the
surficial soil and weathered formational materials.
The locations and descriptions of the site and proposed improvements are based on a site
reconnaissance, observations during site grading, a review of the referenced reports and grading plans,
and our understanding of project development. If project details vary significantly from those described
herein, Geocon Incorporated should be contacted to review and revise of this report.
Project No. 06105-52-24 - 1 - May 7, 2008
3. PREVIOUS SITE DEVELOPMENT
The subject lots were graded to the current configuration during mass grading operations for the
Villages of La Costa - The Oaks North. Grading was performed in conjunction with the observation
and testing services of Geocon Incorporated. A summary of the observations, compaction test results,
and professional opinions pertaining to the grading operations has been presented in the referenced
final report of testing dated November 14, 2007. The majority of the grading operations consisted of
removal and recompaction of surficial soil, placing compacted fill, and performing cuts within
formational material to the design elevations. Due to the difficult excavation characteristics of the
formational materials, cut lots were undercut approximately three to four feet and replaced with
compacted fill to the design elevations. In addition, where a cut-fill transition existed within a lot, the
lot was undercut approximately three to four feet and replaced with compacted fill. A summary of the
as-graded pad conditions for the lots are presented in Table I.
4. SOIL AND GEOLOGIC CONDITIONS
The site is underlain by compacted fill and geologic formations of the Jurassic-age Santiago Peak
Volcanics and Cretaceous aged Escondido Creek Granodiorite. The predominant materials within three
to four feet of grade consist of silty sand and gravel and possess a "very low" to "low" expansion
potential (Expansion Index of 50 or less). The soil type and geologic units are discussed below.
4.1 Compacted Fill
In general, structural fill placed and compacted at the site consisted of material that can be classified
into three zones:
Zone A Material placed within 3 feet from pad grade, 6 feet from parkway grade, and within
roadways to at least 1 foot below the deepest utility consisted of "soil" fill with an
approximate maximum particle dimension of 6 inches.
Zone B Material placed within 10 feet from pad grade and below Zone A, the outer 6 feet of fill
slopes and 2 feet below Zone A for fills in roadways and parkways, consisted of "soil
rock" fill with a maximum particle dimension of 12 inches.
Zone C Material placed below Zone B consisted of "soil rock" fill with a maximum particle
dimension of 48 inches. Larger rocks with a maximum dimension of approximately 8
feet were buried individually during "rock" fill grading operations.
The maximum fill thickness is approximately 54 feet; however, the maximum thickness of fill within
the building pads is approximately 36 feet. Fill soil was placed in conjunction with the observation and
testing services of Geocon Incorporated which have been summarized in the referenced final report of
grading. The compacted fill is considered suitable to provide support for the proposed development.
Project No. 06105-52-24 - 2 - May 7, 2008
4.2 Santiago Peak Volcanics (Jsp)
>*
The Jurassic-aged Santiago Peak Volcanics comprises a portion of the underlying bedrock. These rocks«•were deposited as an alternating succession of volcanic flows, tuffs, and breccias and typically have an
andesite or dacite composition. Subsequently, this sequence of rocks was folded, faulted, and weakly
-• metamorphosed. As encountered during grading, this unit is highly fractured. Closely spaced parallel
m fractures and joints form "sheeted" zones containing colorful alterations and/or oxidation minerals such
as limonite and hematite. Even though the majority of the Santiago Peak Volcanics appears to be•*•
highly fractured and altered, the "sheeted" zones typically have steeply dipping, clay-filled fractures.
m
** 4.3 Escondido Creek Granodiorite (Ke)
m The Cretaceous-aged Escondido Creek Granodiorite intruded the surrounding Jurassic-aged Santiago
*" Peak Volcanics and comprises a portion of the underlying bedrock. In published literature, this unit is
* described as a "leucogranodiorite" because of the overall light color, but averages of composition are
„ typically granodiorite. During grading operations, the exposed bedrock consisted of light brown to
olive, very siliceous, blocky and very strong granitic rock, with little or no weathering. The granitic
rock is considered suitable for the support of the planned development.
m
* 5. GROUNDWATER
We did not encounter groundwater during grading operations. Groundwater is not expected to
* adversely impact the development of the property. Due to the fractured nature of the formational
— materials, we encountered some areas of seepage. Subdrains were installed during remedial grading. It
m is not uncommon for groundwater or seepage conditions to develop where none previously existed.
Groundwater elevations are dependent on seasonal precipitation, irrigation, and land use, among other
"**
factors, and vary as a result. Proper surface drainage will be important to future performance of the
project.
m
6. GEOLOGIC HAZARDSmi
6.1 Faulting and Seismicity
* We used the computer program EQFAULT (Blake, 1998, update 2004) to approximate the distance of
,„ known faults to the site. Within a search radius of 50 miles from the site, 12 known active faults were
identified. The results of the seismicity analyses indicate that the Rose Canyon Fault is the dominant
source of potential ground motion at the site. Earthquakes on the Rose Canyon Fault having a
maximum magnitude of 7.2 are considered to be representative of the potential for seismic ground
* shaking within the property. The "maximum earthquake" is defined as the maximum earthquake that
«. appears capable of occurring under the presently known tectonic framework (California Geologic
* Survey Notes, Number 43). We calculated the estimated maximum ground acceleration expected at the
Project No. 06105-52-24 - 3 - May 7, 2008
site to be approximately 0.30g, using the Sadigh, et al. (1997), acceleration-attenuation relationship.
The earthquake events and site accelerations for the faults considered most likely to subject the site to
ground shaking are presented on Table 6.1. The seismic risk at the site is not considered significantly
greater than that of the surrounding developments or the Carlsbad area in general.
TABLE 6.1
DETERMINISTIC SITE PARAMETERS FOR SELECTED ACTIVE FAULTS
Fault Name
Rose Canyon
Newport-Inglewood (Offshore)
Elsinore-Julian
Elsinore-Temecula
Coronado Bank
Earthquake Valley
Elsinore-Glen Valley
San Joaquin Hills
Palos Verdes
San Jacinto-Anza
San Jacinto-San Jacinto Valley
San Jacinto-Coyote Mountain
Distance
From Site (miles)
8
13
23
23
23
38
38
43
43
46
48
48
Maximum Magnitude
7.2
7.1
7.1
6.7
7.6
6.5
6.8
6.6
7.3
7.2
6.9
6.6
Maximum Site
Accelerations (g)
0.30
0.21
0.13
0.10
0.17
0.05
0.06
0.05
0.07
0.06
0.05
0.04
In the event of a major earthquake along any of the referenced faults or other faults in the Southern
California region, the site could be subjected to moderate to severe ground shaking. With respect to
seismic shaking, the site is considered comparable to others in the general vicinity. While listing of
peak accelerations is useful for comparison of potential effects of fault activity in the region, other
considerations are important in seismic design including the frequency and duration of motion and the
soil conditions underlying the site. The seismic design of structures should be performed in accordance
with the California Building Code (CBC) currently adopted by the City of Carlsbad.
6.2 Liquefaction
Liquefaction typically occurs when a site is located in a zone with seismic activity, on-site soils are
cohesionless, groundwater is encountered within 50 feet of the surface, and soil relative densities are
less than about 70 percent. If the four previous criteria are met, a seismic event could result in a rapid
pore water pressure increase from the earthquake-generated ground accelerations. Due to the dense
nature of the compacted fill and formational materials and the lack of a permanent groundwater table,
the potential for liquefaction occurring at the site is considered to be very low.
Project No. 06105-52-24 -4-May 7, 2008
7. CONCLUSIONS AND RECOMMENDATIONS
7.1 General
7.1.1 No soil or geologic conditions were encountered during previous geotechnical investigations
or grading operations, which in our opinion would preclude the continued development of
the property as presently planned, provided that the recommendations of this report are
followed.
7.1.2 The site is underlain by compacted fill and formational materials of the Santiago Peak
Volcanics and Escondido Creek Granodiorite. We observed the placement of compacted fill
during mass grading operations and performed in-place density tests to evaluate the dry
density and moisture content of the fill material. In general, the in-place density test results
indicate that the fill soil has a dry density of at least 90 percent of the laboratory maximum
dry density near to slightly above optimum moisture content at the locations tested.
7.1.3 The site is considered suitable for the use of conventional foundations and slab-on-grade
and/or a post-tensioned foundation system. Foundation design recommendations are
included herein.
7.1.4 Excavations within the fill materials should generally be possible with moderate to heavy
effort using conventional heavy-duty equipment. Excavations below the fill and into the
Santiago Peak Volcanic or Escondido Creek Granodiorite may require localized blasting and
may generate oversize rocks.
7.2 Finish Grade Soil Conditions
7.2.1 Observations and laboratory test results obtained during mass grading operations indicate
that the prevailing soil conditions within the upper approximately three to four feet of
finish grade pads have is considered to be "non-expansive" and "expansive" (expansion
index [El] of 20 or less and greater than 20) as defined by 2007 California Building Code
(CBC) Section 1802.3.2. Table 7.2 presents soil classifications based on the expansion index.
The prevailing soil conditions possess a "very low" to "low" expansion potential.
Project No. 06105-52-24 - 5 - May 7, 2008
TABLE 7.2.1
SOIL CLASSIFICATION BASED ON EXPANSION INDEX
Expansion Index (El)
0-20
21-50
51-90
91-130
Greater Than 130
Soil Classification
Very Low
Low
Medium
High
Very High
7.2.2 We performed laboratory tests on samples of the site materials to evaluate the percentage of
water-soluble sulfate content. Results from the laboratory water-soluble sulfate content tests
are presented in Table TV and indicate that the on-site materials at the locations tested
possess "negligible" and "moderate" sulfate exposure to concrete structures as defined by
2007 CBC Section 1904.3 and ACI 318. The presence of water-soluble sulfates is not a
visually discernible characteristic; therefore, other soil samples from the site could yield
different concentrations. Additionally, over time landscaping activities (i.e., addition of
fertilizers and other soil nutrients) may affect the concentration. Table 7.2.2 presents a
summary of concrete requirements set forth by UBC Table 19-A-4.
TABLE 7.2.2
REQUIREMENTS FOR CONCRETE EXPOSED TO SULFATE-CONTAINING SOLUTIONS
Sulfate
Exposure
Negligible
Moderate
Severe
Very Severe
Water-Soluble
Sulfate Percent
by Weight
0.00-0.10
0.10-0.20
0.20-2.00
>2.00
Cement
Type
—
II
V
V
Maximum Water
to Cement Ratio
by Weight
—
0.50
0.45
0.45
Minimum
Compressive
Strength (psi)
—
4000
4500
4500
7.2.3 Geocon Incorporated does not practice in the field of corrosion engineering. Therefore, if
improvements that could be susceptible to corrosion are planned, further evaluation by a
corrosion engineer should be performed.
7.3 Seismic Design Criteria
7.3.1 We used the computer program Seismic Hazard Curves and Uniform Hazard Response
Spectra, provided by the USGS to calculate the seismic design criteria. Table 7.3
summarizes site-specific design criteria obtained from the 2007 CBC, Chapter 16 Structural
Project No. 06105-52-24 -6-May 7, 2008
Design, Section 1613 Earthquake Loads. The short spectral response has a period of 0.2
second.
TABLE 7.3
2007 CBC SEISMIC DESIGN PARAMETERS
Parameter
Site Class
Spectral Response - Class B (short), S$
Spectral Response - Class B (1 sec), Sj
Site Coefficient, Fa
Site Coefficient, Fv
Maximum Considered Earthquake
Spectral Response Acceleration (short), SMS
Maximum Considered Earthquake
Spectral Response Acceleration - (1 sec), SMI
5% Damped Design
Spectral Response Acceleration (short), SDS
5% Damped Design
Spectral Response Acceleration (1 sec), SDI
Value
C
l.OSlg
0.408g
1.000
1.392
l.OSlg
0.567g
0.721g
0.378g
D
l.OSlg
0.408g
1.067
1.592
1.154g
0.649g
0.769g
0.433g
IBC-06 Reference
Table 1613.5.2
Figure 1613.5(3)
Figure 1613.5(4)
Table 1613.5.3(1)
Table 1613.5.3(2)
Section 1613.5.3 (Eqn 16-37)
Section 1613.5.3 (Eqn 16-38)
Section 1613.5.4 (Eqn 16-39)
Section 1613.5.4 (Eqn 16-40)
7.3.2 Based on a review of the as-graded conditions presented in the referenced as-graded report,
the lots are assigned the seismic design parameters as indicated in Table V.
7.3.3 Conformance to the criteria for seismic design in Table 7.3 does not constitute any kind of
guarantee or assurance that significant structural damage or ground failure will not occur if a
maximum level earthquake occurs. The primary goal of seismic design is to protect life and
not to avoid damage, since such design may be economically prohibitive.
7.4 Future Grading
7.4.1 Additional grading performed at the site should be accomplished in conjunction with our
observation and compaction testing services. Grading plans for future grading should be
reviewed by Geocon Incorporated prior to finalizing. Trench and wall backfill should be
compacted to a dry density of at least 90 percent of the laboratory maximum dry density near
to slightly above optimum moisture content. This office should be notified at least 48 hours
prior to commencing additional grading or backfill operations.
Project No. 06105-52-24 -7-May 7, 2008
7.5 Foundation and Concrete Slabs-On-Grade Recommendations
7.5.1 The foundation recommendations herein are for proposed one- to two-story residential
structures. The foundation recommendations have been separated into three categories based
on either the maximum and differential fill thickness or Expansion Index. The foundation
category criteria are presented in Table 7.5.1.
TABLE 7.5.1
FOUNDATION CATEGORY CRITERIA
Foundation
Category
I
II
III
Maximum Fill
Thickness, T (feet)
T<20
20<T<50
T>50
Differential Fill
Thickness, D (feet)
~
10<D<20
D>20
Expansion
Index (El)
EI<50
50<EI<90
90<EI<130
7.5.2 Table 7.5.2 presents minimum foundation and interior concrete slab design criteria for
conventional foundation systems.
TABLE 7.5.2
CONVENTIONAL FOUNDATION RECOMMENDATIONS BY CATEGORY
Foundation
Category
I
II
III
Minimum Footing
Embedment
Depth (inches)
12
18
24
Continuous Footing
Reinforcement
Two No. 4 bars
one top and one bottom
Four No. 4 bars
two top and two bottom
Four No. 5 bars
two top and two bottom
Interior Slab
Reinforcement
6x6-10/10 welded wire
mesh at slab mid-point
No. 3 bars at 24 inches
on center, both directions
No. 3 bars at 1 8 inches
on center, both directions
7.5.3 The embedment depths presented in Table 7.5.2 should be measured from the lowest
adjacent pad grade for both interior and exterior footings. The conventional foundations
should have a minimum width of 12 inches and 24 inches for continuous and isolated
footings, respectively. A typical wall/column dimension detail is presented in Figure 2.
7.5.4 The concrete slab-on-grade should be a minimum of 4 inches thick for Foundation
Categories I and II and 5 inches thick for Foundation Category III.
Project No. 06105-52-24 May 7, 2008
7.5.5 Concrete slabs on grade should be underlain by 2 inches of clean sand to reduce the potential
for differential curing, slab curl, and cracking. Slabs that may receive moisture-sensitive floor
coverings or may be used to store moisture-sensitive materials should be underlain by a vapor
inhibitor covered with at least 2 inches of clean sand or crushed rock. The vapor inhibitor
should meet or exceed the requirements of ASTM E 1745-97 (Class A), and exhibit
permeance not greater than 0.012 perm (measured in accordance with ASTM E 96-95. This
vapor inhibitor may be placed directly on finish pad grade. The vapor inhibitor should be
installed in general conformance with ASTM E 1643-98 and the manufacturer's
recommendations. Floor coverings should be installed in accordance with the manufacturer's
recommendations.
7.5.6 As an alternative to the conventional foundation recommendations, consideration should be
given to the use of post-tensioned concrete slab and foundation systems for the support of the
proposed structures. The post-tensioned systems should be designed by a structural engineer
experienced in post-tensioned slab design and design criteria of the Post-Tensioning Institute
(PTI), Third Edition, as required by the 2007 California Building Code (CBC
Section 1805.8). Although this procedure was developed for expansive soil conditions, we
understand it can also be used to reduce the potential for foundation distress due to
differential fill settlement. The post-tensioned design should incorporate the geotechnical
parameters presented on Table 7.5.2 for the particular Foundation Category designated. The
parameters presented in Table 7.5.3 are based on the guidelines presented in the PTI, Third
Edition design manual.
TABLE 7.5.3
POST-TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS
Post-Tensioning Institute (PTI)
Third Edition Design Parameters
Thornthwaite Index
Equilibrium Suction
Edge Lift Moisture Variation Distance, eM (feet)
Edge Lift, yM (inches)
Center Lift Moisture Variation Distance, eM (feet)
Center Lift, yM (inches)
Foundation Category
I
-20
3.9
5.3
0.61
9.0
0.30
II
-20
3.9
5.1
1.10
9.0
0.47
III
-20
3.9
4.9
1.58
9.0
0.66
7.5.7 The foundations for the post-tensioned slabs should be embedded in accordance with the
recommendations of the structural engineer. If a post-tensioned mat foundation system is
planned, the slab should possess a thickened edge with a minimum width of 12 inches and
extend below the clean sand or crushed rock layer.
Project No. 06105-52-24 -9-May 7, 2008
7.5.8 If the structural engineer proposes a post-tensioned foundation design method other than
PTI, Third Edition:
• The deflection criteria presented in Table 7.5.3 are still applicable.
• Interior stiffener beams should be used for Foundation Categories II and III.
• The width of the perimeter foundations should be at least 12 inches.
• The perimeter footing embedment depths should be at least 12 inches, 18 inches and
24 inches for foundation categories I, II, and III, respectively. The embedment
depths should be measured from the lowest adjacent pad grade.
7.5.9 Our experience indicates post-tensioned slabs are susceptible to excessive edge lift,
regardless of the underlying soil conditions. Placing reinforcing steel at the bottom of the
perimeter footings and the interior stiffener beams may mitigate this potential. Current PTI
design procedures primarily address the potential center lift of slabs but, because of the
placement of the reinforcing tendons in the top of the slab, the resulting eccentricity after
tensioning reduces the ability of the system to mitigate edge lift. The structural engineer
should design the foundation system to reduce the potential of edge lift occurring for the
proposed structures.
7.5.10 During the construction of the post-tension foundation system, the concrete should be placed
monolithically. Under no circumstances should cold joints form between the footings/grade
beams and the slab during the construction of the post-tension foundation system.
7.5.11 Category I, II, or III foundations may be designed for an allowable soil bearing pressure of
2,000 pounds per square foot (psf) (dead plus live load). This bearing pressure may be
increased by one-third for transient loads due to wind or seismic forces. The estimated
maximum total and differential settlement for the planned structures due to foundation loads
is 1 inch and '/4 inch, respectively.
7.5.12 Isolated footings, if present, should have the minimum embedment depth and width
recommended for conventional foundations for a particular foundation category. The use of
isolated footings, which are located beyond the perimeter of the building and support
structural elements connected to the building, are not recommended for Category III. Where
this condition cannot be avoided, the isolated footings should be connected to the building
foundation system with grade beams.
7.5.13 For Foundation Category III, consideration should be given to using interior stiffening beams
and connecting isolated footings and/or increasing the slab thickness. In addition,
consideration should be given to connecting patio slabs, which exceed 5 feet in width, to the
building foundation to reduce the potential for future separation to occur.
Project No. 06105-52-24 -10- May 7, 2008
7.5.14 Special subgrade presaturation is not deemed necessary prior to placing concrete; however,
the exposed foundation and slab subgrade soil should be moisture conditioned, as necessary,
to maintain a moist condition as would be expected in any such concrete placement.
7.5.15 Where buildings or other improvements are planned near the top of a slope steeper than 3:1
(horizontahvertical), special foundations and/or design considerations are recommended due
to the tendency for lateral soil movement to occur.
• For fill slopes less than 20 feet high or cut slopes regardless of height, building
footings should be deepened such that the bottom outside edge of the footing is at
least 7 feet horizontally from the face of the slope.
• When located next to a descending 3:1 (horizontal:vertical) fill slope or steeper, the
foundations should be extended to a depth where the minimum horizontal distance is
equal to H/3 (where H equals the vertical distance from the top of the fill slope to the
base of the fill soil) with a minimum of 7 feet but need not exceed 40 feet. The
horizontal distance is measured from the outer, deepest edge of the footing to the
face of the slope. An acceptable alternative to deepening the footings would be the
use of a post-tensioned slab and foundation system or increased footing and slab
reinforcement. Specific design parameters or recommendations for either of these
alternatives can be provided once the building location and fill slope geometry have
been determined.
• If swimming pools are planned, Geocon Incorporated should be contacted for a
review of specific site conditions.
• Swimming pools located within 7 feet of the top of cut or fill slopes are not
recommended. Where such a condition cannot be avoided, the portion of the
swimming pool wall within 7 feet of the slope face be designed assuming that the
adjacent soil provides no lateral support. This recommendation applies to fill slopes up
to 30 feet in height, and cut slopes regardless of height. For swimming pools located
near the top of fill slopes greater than 30 feet in height, additional recommendations
may be required and Geocon Incorporated should be contacted for a review of specific
site conditions.
• Although other improvements, which are relatively rigid or brittle, such as concrete
flatwork or masonry walls, may experience some distress if located near the top of a
slope, it is generally not economical to mitigate this potential. It may be possible,
however, to incorporate design measures which would permit some lateral soil
movement without causing extensive distress. Geocon Incorporated should be
consulted for specific recommendations.
7.5.16 The recommendations of this report are intended to reduce the potential for cracking of slabs
due to expansive soil (if present), differential settlement of existing soil or soil with varying
thicknesses. However, even with the incorporation of the recommendations presented herein,
foundations, stucco walls, and slabs-on-grade placed on such conditions may still exhibit
some cracking due to soil movement and/or shrinkage. The occurrence of concrete shrinkage
Project No. 06105-52-24 - 11 - May 7, 2008
cracks is independent of the supporting soil characteristics. Their occurrence may be reduced
and/or controlled by limiting the slump of the concrete, proper concrete placement and
curing, and by the placement of crack control joints at periodic intervals, in particular, where
re-entrant slab comers occur.
7.5.17 Geocon Incorporated should be consulted to provide additional design parameters as
required by the structural engineer.
7.6 Retaining Walls and Lateral Loads
7.6.1 Retaining walls not restrained at the top and having a level backfill surface should be
designed for an active soil pressure equivalent to the pressure exerted by a fluid density
of 35 pounds per cubic foot (pcf). Where the backfill will be inclined at no steeper than 2:1
(horizontal:vertical), an active soil pressure of 50 pcf is recommended. These soil pressures
assume that the backfill materials within an area bounded by the wall and a 1:1 plane
extending upward from the base of the wall possess an expansion index of 50 or less. For
those lots with finish-grade soils having an expansion index greater than 50 and/or where
backfill materials do not conform to the criteria herein, Geocon Incorporated should be
consulted for additional recommendations.
7.6.2 Unrestrained walls are those that are allowed to rotate more than 0.001H (where H equals the
height of the retaining portion of the wall) at the top of the wall. Where walls are restrained
from movement at the top, an additional uniform pressure of 7H psf should be added to the
active soil pressure. For retaining walls subject to vehicular loads within a horizontal
distance equal to two-thirds the wall height, a surcharge equivalent to 2 feet of fill soil
should be added.
7.6.3 Retaining walls should be provided with a drainage system adequate to prevent the buildup
of hydrostatic forces and waterproofed as required by the project architect. The use of
drainage openings through the base of the wall (weep holes) is not recommended where the
seepage could be a nuisance or otherwise adversely affect the property adjacent to the base
of the wall. The above recommendations assume a properly compacted free-draining backfill
material (El of 50 or less) with no hydrostatic forces or imposed surcharge load. Figure 3
presents a typical retaining wall drainage detail. If conditions different than those described
are expected, or if specific drainage details are desired, Geocon Incorporated should be
contacted for additional recommendations.
7.6.4 In general, wall foundations founded in properly compacted fill or formational materials
should possess a minimum depth and width of one foot and may be designed for an
allowable soil bearing pressure of 2,000 psf, provided the soil within 3 feet below the base of
Project No. 06105-52-24 - 12- May 7, 2008
the wall has an expansion index of 90 or less. The proximity of the foundation to the top of a
slope steeper than 3:1 could impact the allowable soil bearing pressure. Therefore, Geocon
Incorporated should be consulted where such a condition is expected.
7.6.5 For resistance to lateral loads, an allowable passive earth pressure equivalent to a fluid
density of 300 pcf is recommended for footings or shear keys poured neat against properly
compacted fill soil. The allowable passive pressure assumes a horizontal surface extending at
least 5 feet or three times the surface generating the passive pressure, whichever is greater.
The upper 12 inches of material not protected by floor slabs or pavement should not be
included in the design for lateral resistance. A friction coefficient of 0.35 may be used for
resistance to sliding between soil and concrete. This friction coefficient may be combined
with the allowable passive earth pressure when determining resistance to lateral loads.
7.6.6 The structural engineer should determine the seismic design category for the project. If the
project possesses a seismic design category of D, E, or F, the proposed retaining walls
should be designed with seismic lateral pressure. The seismic load exerted on the wall should
be a triangular distribution with a pressure of 22H (where H is the height of the wall, in feet,
resulting in pounds per square foot [psfj) exerted at the top of the wall and zero at the base of
the wall.
7.6.7 Although this seismic loading on the wall was evaluated for an active pressure case and the
walls will be in an at-rest condition, some researchers have reported that this analysis
produces reasonable design earth pressures. Because seismic loads will be analyzed using
lower factors of safety than static earth pressures, we expect the design can be controlled by
static loads.
7.7 Slope Maintenance
7.7.1 Slopes that are steeper than 3:1 (horizontal:vertical) may, under conditions which are both
difficult to prevent and predict, be susceptible to near surface (surficial) slope instability. The
instability is typically limited to the outer three feet of a portion of the slope and usually does
not directly impact the improvements on the pad areas above or below the slope. The
occurrence of surficial instability is more prevalent on fill slopes and is generally preceded
by a period of heavy rainfall, excessive irrigation, or the migration of subsurface seepage.
The disturbance and/or loosening of the surficial soils, as might result from root growth, soil
expansion, or excavation for irrigation lines and slope planting, may also be a significant
contributing factor to surficial instability. It is, therefore, recommended that, to the
maximum extent practical: (a) disturbed/loosened surficial soils be either removed or
properly recompacted, (b) irrigation systems be periodically inspected and maintained to
eliminate leaks and excessive irrigation, and (c) surface drains on and adjacent to slopes be
Project No. 06105-52-24 - 13- May 7, 2008
periodically maintained to preclude ponding or erosion. It should be noted that although the
incorporation of the above recommendations should reduce the potential for surficial slope
instability, it will not eliminate the possibility, and, therefore, it may be necessary to rebuild
or repair a portion of the project's slopes in the future.
7.8 Site Drainage
7.8.1 Adequate site drainage is critical to reduce the potential for differential soil movement,
erosion and subsurface seepage. Under no circumstances should water be allowed to pond
adjacent to footings. The site should be graded and maintained such that surface drainage is
directed away from structures in accordance with 2007 CBC 1803.3 or other applicable
standards, hi addition, surface drainage should be directed away from the top of slopes into
swales or other controlled drainage devices. Roof and pavement drainage should be directed
into conduits that carry runoff away from the proposed structure.
7.8.2 Underground utilities should be leak free. Utility and irrigation lines should be checked
periodically for leaks for early detection of water infiltration and detected leaks should be
repaired promptly. Detrimental soil movement could occur if water is allowed to infiltrate
the soil for a prolonged period of time.
7.8.3 Landscaping planters adjacent to paved areas are not recommended due to the potential for
surface or irrigation water to infiltrate the pavement's subgrade and base course. We
recommend that drains to collect excess irrigation water and transmit it to drainage
structures, or impervious above-grade planter boxes be used. In addition, where landscaping
is planned adjacent to the pavement, we recommended construction of a cutoff wall along
the edge of the pavement that extends at least 6 inches below the bottom of the base material.
7.8.4 If detention basins, bioswales, retention basins, or water infiltration devices are being
considered, Geocon Incorporated should be retained to provide recommendations pertaining
to the geotechnical aspects of possible impacts and design. Distress may be caused to
planned improvements and properties located hydrologically downstream. The distress
depends on the amount of water to be detained, its residence time, soil permeability, and
other factors. We have not performed a hydrogeology study at the site. Downstream
properties may be subjected to seeps, springs, slope instability, raised groundwater,
movement of foundations and slabs, or other impacts as a result of water infiltration.
7.9 Foundation Plan Review
7.9.1 Geocon Incorporated should review the foundation plans for the project prior to final design
submittal to determine whether additional analysis and/or recommendations are required.
Project No. 06105-52-24 - 14 - May 7, 2008
LIMITATIONS AND UNIFORMITY OF CONDITIONS
1. Recommendations of this report pertain only to the site investigated and are based upon the
assumption that the soil conditions do not deviate from those disclosed in the investigation. If
any variations or undesirable conditions are encountered during construction, or if the
proposed construction will differ from that anticipated herein, Geocon Incorporated should be
notified so that supplemental recommendations can be given. The evaluation or identification
of the potential presence of hazardous or corrosive materials was not part of the scope of
services provided by Geocon Incorporated.
2. This report is issued with the understanding that it is the responsibility of the owner, or of his
representative, to ensure that the information and recommendations contained herein are
brought to the attention of the architect and engineer for the project and incorporated into the
plans, and the necessary steps are taken to see that the contractor and subcontractors carry out
such recommendations in the field.
3. The findings of this report are valid as of the present date. However, changes in the conditions
of a property can occur with the passage of time, whether they are due to natural processes or
the works of man on this or adjacent properties. 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 should not be relied
upon after a period of three years.
4. The firm that performed the geotechnical investigation for the project should be retained to
provide testing and observation services during construction to provide continuity of
geotechnical interpretation and to check that the recommendations presented for geotechnical
aspects of site development are incorporated during site grading, construction of
improvements, and excavation of foundations. If another geotechnical firm is selected to
perform the testing and observation services during construction operations, that firm should
prepare a letter indicating their intent to assume the responsibilities of project geotechnical
engineer of record. A copy of the letter should be provided to the regulatory agency for their
records. In addition, that firm should provide revised recommendations concerning the
geotechnical aspects of the proposed development, or a written acknowledgement of their
concurrence with the recommendations presented in our report. They should also perform
additional analyses deemed necessary to assume the role of Geotechnical Engineer of Record.
Project No. 06105-52-24 May 7, 2008
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SUBJECT TO A LICENSING AGREEMENT. THE INFORMATION IS FOR ILLUSTRATIVE PURPOSES ONLY; IT I:Mf-iT iMTCkincn er\o c-i ICMT-C i ice no ppi IAMHC AMrt CMAI i wnT BC opDDnni men RV m IPKJT rl IPMT
GEOCON ^
INCORPORATED ^^
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974.
PHONE 858 558-6900 - FAX 858 558-6159
ME/AML I 1 DSK/GTYPD
VICINITY MAP
VILLAGES OF LA COSTA - THE OAKS NORTH
NEIGHBORHOOD 3.3 NORTH
CARLSBAD, CALIFORNIA
DATE 05-07- 2008 1 PROJECT NO. 06105 - 52 - 24 I FIG. 1
WALL FOOTING
CONCRETE SLAB
^
SAND
*'
VISQUEEN
B UJ
Q
FOOTING*
WIDTH
PAD GRADE
1- Q.
COLUMN FOOTING
CONCRETE SLAB
SAND
VISQUEEN
O-
* .« 1
FOOTING WIDTH*
NO SCALE
*....SEE REPORT FOR FOUNDATION WITDH AND DEPTH RECOMMENDATION
WALL / COLUMN FOOTING DIMENSION DETAIL
GEOCON
INCORPORATED
GEOTEOHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
VILLAGES OF LA COSTA - THE OAKS NORTH
NEIGHBORHOOD 3.3 NORTH
CARLSBAD, CALIFORNIA
FK/AML DSK/EOOOO DATE 05-07-2008 PROJECT NO. 06105-52-24 FIG. 2
- Er
- I
GROUND SURFACE
PROPOSED
RETAINING WALL
TEMPORARY BACKCUT
PER OSHA
GROUND SURFACE -
MIRAFI140N FILTER FABRIC
{OR EQUIVALENT)
OPEN GRADED
3/4" MAX. AGGREGATE
1"
\! 4" DIA. PERFORATED SCHEDULE
- 40 PVC PIPE EXTENDED TO
APPROVED OUTLET
2/3 H
PROPOSED
GRADE"
WATER PROOFING
"PER ARCHITECT
DRAINAGE PANEL (MIRADRAIN 6000
' OR EQUIVALENT)
3/4" CRUSHED ROCK
(1 CU.FT./FT.)
FILTER FABRIC ENVELOPE
MIRAFI 140N OR EQUIVALENT
4" D1A. SCHEDULE 40 PERFORATED
PVC PIPE OR TOTAL DRAIN EXTENDED
TO APPROVED OUTLET
NOTE:
DRAIN SHOULD BE UNIFORMLY SLOPED TO GRAVITY OUTLET
OR TO A SUMP WHERE WATER CAN BE REMOVED BY PUMPING
TYPICAL RETAINING WALL DRAIN DETAIL
GEOCON (&)
INCORPORATED XSir
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 85S 558-6900 - FAX 858 558-6159
ME /AMI 1 1 DSK/GTYPD
VILLAGES OF LA COSTA - THE OAKS NORTH
NEIGHBORHOOD 3.3 NORTH
CARLSBAD, CALIFORNIA
DATE 05 - 07 - 2008 J PROJECT NO. 61 05 - 52 - 24 | FIG. 3
TABLE I
SUMMARY OF AS-GRADED BUILDING PAD CONDITIONS
AND RECOMMENDED FOUNDATION CATEGORIES FOR
VILLAGES OF LA COSTA - THE OAKS NORTH, NEIGHBORHOOD 3.3 - NORTH
LOTS 1 THROUGH 18, LOTS 36 THROUGH 79 AND LOTS 116 THROUGH 120
Lot No.
1
2
3
4
5
6
1
8
9
10
11
12
13
14
15
16
17
18
36
37
38
39
40
41
42
43
44
45
46
47
48
49
Pad Condition
Fill
Undercut due to cut-fill transition
Undercut due to cut-fill transition
Undercut due to cut-fill transition
Fill
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Approximate
Maximum
Depth of Fill
(feet)
12
16
15
14
20
4
4
5
5
5
4
4
5
5
4
4
4
4
4
4
4
5
4
4
4
4
4
4
4
6
6
5
Approximate
Maximum
Depth of Fill
Differential
(feet)
5
10
12
10
13
1
1
1
1
1
1
1
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
3
3
2
Expansion
Index
0
0
0
0
0
20
20
20
20
20
5
5
5
5
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
3
3
3
Recommended
Foundation
Category
I
II
II
II
II
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
Project No. 06105-52-24 May 7, 2008
TABLE I (Continued)
SUMMARY OF AS-GRADED BUILDING PAD CONDITIONS
AND RECOMMENDED FOUNDATION CATEGORIES FOR
VILLAGES OF LA COSTA - THE OAKS NORTH, NEIGHBORHOOD 3.3 - NORTH
LOTS 1 THROUGH 18, LOTS 36 THROUGH 79 AND LOTS 116 THROUGH 120
Lot No.
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
116
117
Pad Condition
Undercut due to cut-fill transition
Undercut due to cut-fill transition
Undercut due to hard rock
Undercut due to cut-fill transition
Undercut due to cut-fill transition
Undercut due to cut-fill transition
Undercut due to cut-fill transition
Undercut due to hard rock
Undercut due to hard rock
Undercut due to cut/fill transition
Undercut due to cut/fill transition
Fill
Fill
Fill
Undercut due to cut-fill transition
Undercut due to cut-fill transition
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Undercut due to hard rock
Fill
Fill
Undercut due to cut-fill transition
Undercut due to cut-fill transition
Undercut due to hard rock
Fill
Fill
Fill
Fill
Undercut due to cut-fill transition
Undercut due to cut-fill transition
Approximate
Maximum
Depth of Fill
(feet)
16
6
4
7
17
15
11
5
5
6
15
31
33
21
20
6
5
4
5
5
4
14
17
14
10
4
6
15
18
20
22
30
Approximate
Maximum
Depth of Fill
Differential
(feet)
13
2
1
4
14
11
7
1
1
2
11
20
17
6
16
3
1
1
2
2
1
10
9
10
7
1
3
8
7
10
18
25
Expansion
Index
36
36
0
0
36
0
0
0
0
1
1
1
1
1
38
38
0
0
0
0
0
0
0
0
0
3
3
3
0
0
1
1
Recommended
Foundation
Category
II
I
I
I
II
II
I
I
I
I
II
III
II
II
II
I
I
I
I
I
I
II
I
II
I
I
I
I
I
II
II
III
Project No. 06105-52-24 May 7, 2008
TABLE I (Continued)
SUMMARY OF AS-GRADED BUILDING PAD CONDITIONS
AND RECOMMENDED FOUNDATION CATEGORIES FOR
VILLAGES OF LA COSTA - THE OAKS NORTH, NEIGHBORHOOD 3.3 - NORTH
LOTS 1 THROUGH 18, LOTS 36 THROUGH 79 AND LOTS 116 THROUGH 120
Lot No.
118
119
120
Pad Condition
Undercut due to cut-fill transition
Undercut due to cut-fill transition
Undercut due to cut-fill transition
Approximate
Maximum
Depth of Fill
(feet)
29
36
25
Approximate
Maximum
Depth of Fill
Differential
(feet)
26
33
22
Expansion
Index
1
1
1
Recommended
Foundation
Category
III
III
III
TABLE II
SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS
ASTM D 4829-03
Sample
No.
EI-BB
EI-BD
EI-BE
EI-BF
EI-BG
EI-BH
EI-BI
EI-BJ
EI-BK
EI-BM
EI-BS
EI-BT
EI-BU
EI-BV
EI-BW
EI-BX
EI-CA
EI-CB
EI-CC
Moisture Content (%)
Before Test
8.1
10.8
9.6
9.5
8.1
8.1
8.4
10.4
8.7
7.7
7.7
8.8
8.3
7.6
7.6
7.8
8.5
7.4
7.4
After Test
13.1
19.7
17.0
18.5
13.9
13.7
12.8
18.1
13.3
13.7
12.6
14.7
13.2
12.5
13.4
13.4
13.9
13.7
13.6
Dry Density
(pcf)
118.0
108.6
112.7
110.0
118.3
118.0
117.6
109.5
117.5
118.7
118.5
117.2
117.9
119.0
118.6
118.3
117.8
118.5
118.5
Expansion
Index
0
20
3
36
0
0
1
38
0
0
1
3
0
0
0
0
5
1
1
UBC
Classification
Very Low
Very Low
Very Low
Low
Very Low
Very Low
Very Low
Low
Very Low
Very Low
Very Low
Very Low
Very Low
Very Low
Very Low
Very Low
Very Low
Very Low
Very Low
Project No. 06105-52-24 May 7, 2008
TABLE III
SUMMARY OF FINISH-GRADE EXPANSION INDEX TEST RESULTS
VILLAGES OF LA COSTA -THE OAKS NORTH, NEIGHBORHOOD 3.3 NORTH
LOTS 1 THROUGH 18, LOTS 36 THROUGH 79 AND LOTS 116 THROUGH 120
Lot No.
1 through 5
6 through 10
11 through 14
15 through 18
36 and 37
38 through 40
41 through 43
44 through 46
47 through 49
50 and 51
52 and 53
54
55 through 58
59 through 63
64 through 65
66 through 70
71 through 74
75 through 77
78 and 79
116 through 120
Sample at Finish Grade
EI-BB
EI-BD
EI-CA
EI-CB
EI-BS
EI-BV
EI-BW
EI-BX
EI-BE
EI-BF
EI-BG
EI-BF
EI-BH
EI-BI
EI-BJ
EI-BK
EI-BU
EI-BT
EI-BM
EI-CC
Expansion Index
0
20
5
1
1
0
0
0
3
36
0
36
0
1
38
0
0
3
0
1
UBC Classification
Very Low
Very Low
Very Low
Very Low
Very Low
Very Low
Very Low
Very Low
Very Low
Low
Very Low
Low
Very Low
Very Low
Low
Very Low
Very Low
Very Low
Very Low
Very Low
TABLE IV
SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE CONTENT TEST RESULTS
CALIFORNIA TEST NO. 417
Sample No.
EI-BB
EI-BD
EI-BE
EI-BF
EI-BG
EI-BH
EI-BI
Water-Soluble Sulfate (%)
0.007
0.031
0.036
0.090
0.011
0.008
0.014
Sulfate Exposure
Negligible
Negligible
Negligible
Negligible
Negligible
Negligible
Negligible
Project No. 06105-52-24 May 7, 2008
TABLE IV (Continued)
SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE CONTENT TEST RESULTS
CALIFORNIA TEST NO. 417
Sample No.
EI-BJ
EI-BK
EI-BT
EI-BV
EI-BX
EI-CA
EI-CB
EI-CC
Water-Soluble Sulfate (%)
0.101
0.009
0.011
0.013
0.007
0.038
0.034
0.012
Sulfate Exposure
Moderate
Negligible
Negligible
Negligible
Negligible
Negligible
Negligible
Negligible
TABLE V
SUMMARY OF SOIL PROFILE TYPE
Lot Nos.
1 through 4
5
6 through 1 8
36 through 60
61 through 64
65 through 78
79
116 through 120
2007 CBC Classification
C
D
C
C
D
C
D
D
Project No. 06105-52-24 May 7, 2008