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Geotechnical • Geologic • Coastal • Environmental
5741 Palmer Way • Carlsbad, California 92010 • (760) 438-3155 • FAX (760) 931-0915
March 6, 2009
Brookfield San Diego Builders, Inc.
12865 Pointe Del Mar, Suite 200
Del Mar, California 92014
Attention: Mr. Adam Pevney
w.o. 5353-B1-SC
Subject: Report of Rough Grading, Planning. Area 22 of Robertson Ranch,
East Village, Carlsbad, San Diego County, California
Dear Mr. Pevney:
This report presents a summary of the geotechnical testing and observation services
provided by GeoSoils, Inc. (GSI) during the rough earthwork construction phase of
development associated with the development of Planning Area 22 (PA-22) of Robertson
Ranch East Vii/age project, in the City of Carlsbad, San Diego County, California.
Earthwork was performed in conjunction with the grading of the larger Robertson Ranch
East Village. Earthwork commenced in June 2007, and was generally completed within
a majority of the site in January 2009, and includes driveway access to Cannon Road, a
office building site, and parking areas. The easternmost portion of the site, including a
planned "RV" storage area and additional parking areas, is presently an area of "planned
future grading," and is not under the purview of this report (N.A.P.).
PURPOSE OF EARTHWORK
The purpose of this phase of grading was to prepare the site for the construction of a three
story office building, driveway access to Cannon Road, parking areas, an "RV" storage
area (not complete), and associated surface and subsurface improvements. Cut-and-fill
grading techniques were utilized to attain the desired graded configurations. Existing
colluvium (topsoil), near surface alluvium, and weathered formational material were
removed to suitable earth material (as defined in the approved report for this portion of the
project tract [GSI, 2007b]), and recompacted as fill. Additional fill soils were imported to
the site to achieve the desired graded configurations. Rough .gradingis generally.
completed throughout a majority of PA-22, including the office building site and the
remaining portions of PA-22 west of the RV storage lot. The RV storage lot area, and
planned parking areas south of the storage lot are presently not graded to design grades,
as indicated on Plate 1 (Geotechnical Map). As such, these areas are not included under
the purview of this report.
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The approximate limits of grading under the purview of this report are shown on the.
Geotechnical Map (Plate 1), which use the 40-scale grading plan for this project, prepared
by O'Day Consultants (O'Day, 2008), as a base.
ENGINEERING GEOLOGY
Subsurface geologic conditions exposed during the process of rough grading Were
observed by a representative of GSI. Prior to grading, earth materials onsite consisted of
surficial deposits of colluvium (topsoil), and alluvium, underla,in by terrace deposits
(considered bedrock), or formational sediments belonging to the Santiago Formation (also
considered bedrock). The subsurface conditions exposed were generally as anticipated
per our approved geotechnical report (GSI, 2007b). Perimeter grading, along the north
side of PA-22, as indicated on Plate 1 , was performed prior to this phase of earthwork with
geotechnical observation and testing services provided by GSI (2006e and 2007a). Most
of the grading of PA-22 was generally completed at the same time as grading of the larger
Robertson Ranch East Village project, north of Cannon Road.
GEOLOGIC STRUCTURE
. As observed onsite, the bedding structure observed within terrace deposits is generally
thickly bedded and sub-horizontal. Bedding structure was not well developed within the
thickly-bedded Santiago Formation, but generally dips on the order of 5 to 10 degrees to
the northwest, based on mapping in the vicinity and a review of GSI (2004 and 200Yb).
GROUNDWATER
Naturally occurring perched groundwater wa~ encountered at depths on the order of
approximately 10 feet below·the pre-construction grades (GSI, 2007b), or approximately
20 feet below the building pad ele,(ation shown on Plate 1. Due to the lack of suitable
free-flowing outlets, and canyon areas to concentrate subsurface watet:, and lack of a
gradient at flow-line elevations, subdrains were not constructed. Regional groundwater
should not significantly affect the performance ofthe fill, provided that prudent surface and
subsurface drainage practices are incorporated into the construction plans.
Perched groundwater conditions may develop in the future due to rainfall, excess irrigation,
owner altered drainage, or damaged utilities, and should be anticipated along cut/fill
contacts or areas within compacted fill with contrasting permeabilities. Should
manifestations of perched conditions (Le., seepage, develop in. the future), this office
should assess the conditions and provide mitigative recommendations, as necessary.
Brookfield San Diego Builders, Inc.
PA-22 Robertson Ranch, East Village
File:e:\wp9\5300\5353b1.ror.pa22
GeoSoils, Ine.
w.o. 5353·B1-SC
March 6, 2009
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EARTHWORK CONSTRUCTION
Earthwork operations have been completed in general accordance with the City grading
ordinance, approved recommendations provided by GSI (see the Appendix), and the
guidelines provided in the field by this office. Observations during grading included
removals, excavation, and fill placement, along with general grading procedures of
compacted fills by the contractor. Table 1 presents a summary of compaction test results.
Rough Grading
Preparation of Existing Ground
1. . Deleterious material, such as concentrated organic matter and miscellaneous
debris, were stripped from the surface and disposed of beyond the limits of grading
. for the subject area, prior to placing any fill.
2. Loose surficial materials (Le., existing topsoils, colluvium, near surface alluvilJm, and
unsuitable formational soils), were removed to expose suitable bearing $oils, as
defined in the approved report for the site.
3. Due to the presence of groundwater, saturated alluvial soils (up to approximately
25 feet thick) were left in place. The distribution of alluvial soils left in place is
shown on Plate 1 .
4.
5.
Site grading resulted in approximately 13 to 14 .feet of compacted fiJI placed
beneath the planned office building site (see Plate 1). As such, cut/fill transitions
were not created in this area.
Subsequent to completing removals, areas to receive compacted fill were scarified,
moisture conditioned, and then compacted to attain a minimum relative compaction
of 90 percent (ASTM D 1557). These areas were then brought to ·grade with fill
compacted to a minimum 90 percent relative compaction, based on field
observations.
6. All processing of original ground in areas to receive fill, shown on Plate 1, was
observed by a representative of GSI. Plate 1 utilizes the 40-scale grading plan
prepared by O'Day (2008), as a base map.
Fill Placement
Fill consisted of onsite and import materials which were placed in th.in lifts, approximately
4 to 8 inches in thickness, brought to at least optimum moisture content, and compacted
to attain a minimum 90 percent relative compaction per ASTM 1557. Approximate as-built
fill depths are shown in on Plate 1, and generally vary on the order of approXimately 10 to
15 feet. Compaction test results for fills are presented in the attached Table 1.
Brookfield San Diego Builders, Inc.
PA-22 Robertson Ranch, East Village
File:e:\wp9\5300\5353b1.ror.pa22
GeoSoils, lne.
W.O. 5353-B1':SC
Marcn 6, 2009
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Fill containing rock fragments up to approximately 24 inches in size, more or less, were
routinely placed at depth, below about 5 feet, per the approved report (GSI, 2007b) , within
the vicinity of the planned office building site. Elsewhere onsite, rocky materials were
placed locally within 5 feet of finish grade, at the direction of the client. Oversize material
was placed in general accordance with recommendations presented in the approved
report (GSI, 2007b) , and placed no closer than approximl:itely 5 feet from finish grade
within the appropriate footprint ofthe proposed building. Nonetheless, shallow excavation
may potentially encounter oversize materials within the foundation and utility trenches, and
this condition should be anticipated. Oversize materials from such excavation will likely
require offsite disposal.
Slopes
Graded Slopes •
Graded slopes constructed uflder the purview of this report are generally on the order of
approximately 10 feet in height, or less, and should typically perform satisfactorily with
respect to gross and surficial stability under normal conditions of care, maintenance, and
rainfall (semi-arid). Fill slopes, constructed under the purview ofthis report, were provided
with a basal bench, or keyway, excavated into suitable earth material, in general
accordance with the approved GSI recommendations (see the Appendix). Cutslopes were
not constructed during this phase of grading, but are planned during future improvement
of the RV storage lot.
Temporary Slopes
Any proposed/future temporary construction slopes may be constructed at a gradjent of
1:1 (horizontal:vertical [h:v]), or flatter, in compacted fill (provided adverse conditions are
not present, as evaluated by GSI prior to workers entering trenches), provided seepage
or groundwater is not present. Shallow utility trenches may be excavated in accordance
with guidelines presented in Title 8 of the California Code of Regulations for Excavation,
Trenches, and Earthwork, with respect to "Type 8" soil (compacted fill), again provided
seepage or groundwater is not present. Construction materials and/or stockpiled soil
should not be stored within 'H' from the top of any temporary slope, where 'H' is the height
of the slope, in feet. Temporary/permanent proVisions should be made to direct any
potential runoff away from the top of temporary slopes.
Natural Slopes
Natural slopes are not present within PA-22.
Subdrainage
Due to the lack of suitable free-flowing outlets, and canyon areas to concentrate
subsurface water, and lack of a gradient at flow-line elevations, subdrains were not
Brookfield San Diego Builders, Inc.
PA-22 Robertson Ranch, East Village
File:e:\wp9\5300\5353b1.ror.pa22
GeoSoils, Ine.
w.o. 5353-B1-SC
March 6: 2009
Page 4
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constructed. Regional groundwater should not significantly affect tne performance of the
fill, provided that prudent surface and subsurface drainage practices are incorporated into
the construction plans.
Field Testing
1. Field density tests were performed using the sand-cone method (ASTM D 1556) and
nuclear (densometer) method (ASTM 0 2922and D 3017). Tests taken for the
Robertson Ranch project were taken in consecutive numerical order. However, only
tests within the subject site, under the purview of this report, are presented in
Table 1 at the end of the text; therefore, test sequencing may be periodically
non-consecutive, but consistent with the testing on the tract as a whole. The
approximate locations of field density tests are shown on the Geotechnical Map
(Plate 1), which utilize the 40-scale grading plans, prepared by O'Day(2008), as a
base map.
Where fills contained a significant amount of rock, precluding testing in accordance
. with ASTM D 1556, D 2922, and D 3017, a "method only" (Nichols, 1976) technique
was employed in conjunction with areas where testing,. using the procedures
described above, could be performed. In these areas, the material was spread out
in lifts on the order of 1 to 2 feet thick, mixed with sandy materials, flooded with
water, and rolled with fully loaded, heavy rock trucks. Rolling was completed until
further movement of the material was not observed. Once an areas was
compacted, test pits were completed to evaluate moisture content and the
presence of void spaces. Where adverse conditions were observed, these areas
were re-excavated and replaced with a suitable soil rock mixture until satisfactory.
2. Field density tests were taken at periodic intervals and random locations to check
the compactive effort provided by the contractoL Rock corrections were applied
during testing of fill with significant rock fragments, as appropriate. Based on the
operations observed, test results presented herein are generally considered
representative of the fills observed under the purview of this report ..
3. Visual classification of the soils in the field, as well as random laboratory testing,
was the basis for determining which maximum dry density value to use for a given
density test.
4. Testing and observations were performed on a full time, and part-time basis, as
solely determined by the client/contractor.
Brookfield San Diego Builders, Inc.
PA-22 Robertson Ranch, East Village
File:e:\wp9\5300\5353b1.ror.pa22
GeoSoils, Ine.
w.o. S3S3~B1-SC
March 6, 2009
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LABORATORY TESTING
Moisture-Density Relations
The laboratory maximum dry density and optimum moisture content for each major soil .
type occurring within PA-22 was determined in general accordance with test method
ASTM 0 1557. Non-consecutive lettering indicated in the following table is a result of soil
types being part of the soil type sequence for the larger Robertson Ranch development.
The following table presents the test results:
B -Dark Brown, Clayey SAND 114.0 13.0
C -Gray Brown, Clayey SAND 120.5 13.0
F-Gray Brown, Gravelly SAND (import) 134.0 8.0
H -Gray Brown, SAND (import) 134.0 9.0
J -Gray~ Clayey SAND 121.0 12.5
DO -Gray Gravelly Sand frock (import) 144.0 8.0
ZZ -Brown Silty SAND (import) 128.5 9.0
BBB -Brown Clayey SAND (import) 118.5 14.0
CCC-Brown 124.0 12.0
Expansion Index
Expansion Index (E.I.) tests were performed for the representative foundation soil types
exposed near finish grade, in general accordance with ASTM 0 482~. Based on our
expansive soil evaluation, the expansion index of site soils varies from approximately 41
to 77, or lowto medium expansive. Medium expansive soil conditions shall be considered
for foundation design. . . .
Atterberg Limits
Laboratory testing was performed to evaluate the Atterberg Limits (liquid limit, plastic limit,
and plasticity index) in general accordance with ASTM 0 4318 for representative soils
exposed near finish grade that exhibited an E.1. greater than 20 or had high fines
(-200 sieve) content. The results of Atterberg Limittesting are as follo'Ns: Liquid Limit = 47,
Plastic Limit = 17, Plasticity Index = 30, and shall be considered in foundation design.
Brookfield San Diego Builders, Inc.
PA-22 Robertson Ranch, East Village
File:e:\wp9\5300\5353b1.ror.pa22
GeoSoils, lne.
W.O. 5353-B1-SC
March 6, 2009
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Corrosion Analysis
Representative samples of the site materials has been analyzed for soluble sulfates; soil
pH, and saturated resistivity by Schiff Associates, Inc. (corrosion consultants). Based upon
the laboratory testing, the majority of site soils are considered to be negligible (sulfate
class SO, American Concrete Institute [ACI] 318-08) with respect to water soluble sulfate
exposure to concrete. This classification is in accordance with Tables 4.2.1 arid 4.3.1 of
ACI 318-08 (California Building Code [CBC], California Building Standards Commission
[CBSC], 2007). Soils are relatively neutral with respect to soil acidity/alkalinity (pH = 7.4
to 7.6 [Romanoff, 1957]), and are very corrosive to exposed ferrous metals in a saturated
state (saturated resistivity <1,000 ohm-cm). The chloride ion content (304 to 339 ppm) in
soil fo~ the site was also noted to be slightly above action levels per Caltrans (1999)
(Le., >300 ppm). It is our understanding that standard concrete cover over reinforcing
steel is usually appropriate for these conditions; however, a: corrosion engineer should be
consulted to provide specific recommendations regarding foundations and buried piping,
etc,
FOUNDATION RECOMMENDATIONS
In the event that information concerning the proposed development plan is not correct, or
any changes in the design, location or loading conditions of the proposed structure are
made, the conclusions and recommendations contained in this report shall not be
considered valid unless the changes are reviewed and conclusions of this report are
modified or approved in writing by this office. The conclusions and recommendations
presented in GSI (2007b) are generally considered valid and applicable unless speCifically
superceded in the text of this ·report. Recommendations for conventional and
post-tensioned foundation systems are provided in the following sections.
RECOMMENDATIONS -CONVENTIONAL FOUNDATIONS
General
The foundation design and construction recommendations are based on laboratory testing
and engineering analysis of onsite earth materials by GSI. The foundation systems may
be used to support the proposed structures, provided they are founded in competent
bearing material (Le., founded entirely in compacted fill or rippable bedrock), with no
exposed transitions. For medium expansive soil conditions (E.1. >21 and < 90), and
where the P.J. is greater than 15, conventional foundations may be used, provided that th.ey
are designed in accordance with Chapter 18 (Section 1805A.8) ofthe CSC (CSSC, 2007).
This implies that the Code may require the use of more onerous foundations
(Le., post-tension, mat, etc.).
Brookfield San Diego Builders, Inc.
PA-22 Robertson Ranch, East Village
File:e:\wp9\5300\5353b~ .ror.pa22
GeoSoils, lne.
W.O. 5353-S1-SC
Marth 6, 2009
Pagel
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RECOMMENDATIONS -FOUNDATIONS
General
In the event that the information concerning the proposed development concept is not
correct or any changes in the design, location, or loading conditions of the proposed
structure(s} are made, the conclusions and recommendations contained in this report are
for the subject site only and shall not be considered valid unless the changes are reviewed
and conclusions of this report are modified or approved in writing by this office.
The information and recommendations presented in this section are considered minimums
and ar~ not meant to supercede design(s} by the project structural engineer or civil
engineer specializing in structural design. Upon request, GSI could provide additional
consultation regarding soil parameters, as related to foundation design. They are
considered preliminary recommendations for proposed construction, in consideration of
our field investigation, laboratory testing, and engineering analysis.
At this time, proposed construction is to consist of a three floor (maximum) office building. '
For this type of commercial building, GSI anticipates average and maximum static column
loads of 50 and 150 kips, respectively. Maximum building perimeter wall loads are
anticipated to be on the order of 2 to 5 kips per lineal foot of wall. The foundation design
and construction recommendations are based on laboratory testing and engineering
analysis of onsite earth materials by GSI. The fmmdation systems may be us~d to support
the proposed structure(s), provided they are founded in competent bearing material
(compacted fill). The proposed foundation systems should be designed and constructed
in accordance with the guidelines contained in the eBse (2007). As indicated previously,
for medium expansive soil conditions, where the P.1. is greater than 15, conventional
foundations may be used, provided that they are designed in accordance With Chapter 18
(Section 1805A.8) of the CBC (CBSC, 2007). This implie$ that the Code may require the
use of more onerous foundations (i.e., post-tension, mat, etc.).
The information and recommendations presented in this section are minimums and not
meantto supercede design(s) by the project structural engineer. Upon request, GSI could
provide additional information/consultation regarding soil parameters, as related to
foundation design.
As-Built Conditions
As-built soil conditions to be considered in foundation design and construction are as
follows:
• Our review, field work, and laboratory testing indicates that onsite soils have a low
to medium expansion potential (expansion index [E.I.] range of 41 to 77), and a
plasticity index (PI) of 30.
Brookfield San Diego Builders, Inc.
PA-22 Robertson Ranch, East Village
File:e:\wp9\5300\5353b1.ror.pa22
GeoSoils, lne.
W.O. 5353-B1-SC
March 6, 2009
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• As-built fill thicknesses range from approximately 13 to 14 feet acr6ss the building
area, and 10 to 15 feet across the site.
Seismic Shaking Parameters
The table below summaries the site-specific design criteria obtained per the 2007 GBC.
We used the computer program Seismic Hazard Curves and Uniform Hq,zard Response
Spectra, provided by the U.S.G.S. The short spectral response uses a period of
0.2 seconds.
Site Class D Table 1613.5.2
Spectral Response -(0.2 sec), Ss 1.15g Figure 1613.5(3)
Spectral Response -(1 sec) S, O.44g Figure 161
Site Coefficient, Fa 1.04 Table 1613.5.3(1)
Site Coefficient, Fv 1.56 Table 1613.5.3(2)
Maximum Considered Earthquake·Spectral 1.20g Section 1613.5.3
Response Acceleration (0.2 sec) SMS (Eqn 16-37)
Maximum Considered Earthquake Spectral 0.68g Section 1613.5.3
Response Acceleration (1 sec), SM' (Eqn 16-38)
5% Damped Design Spectral 0.79g Section 1613.5.4
Response Acceleration (0.2 sec), SDS (Eqn 1
5% Damped Design Spectral 0.46g Section .1613.5.4
n 1
A probabilistic peak horizontal ground acceleration (PHSA) of 0.28 g was evaluatedforthis
site (GSI, 2007b). This value was chosen as it corresponds to a 10 percent probability of
exceedence in 50 years (or a 475-year return period).
Conformance to the criteria above for seismic design does not constitute any kind of
guarantee or assurance that significant structural damage or ground failure will riot occur
in the event of a large earthquake. The primary goal of seismic design is to protect life, not
to eliminate all damage, since such design may be economically prohibitive.
Foundation Design -Spread and Continuous Footings
Based on the anticipated foundation loads and preliminary design information provided
to us, it is our opinion that the proposed structure(s) can favorably be supported on the
compacted fill soils. Building loads may be supported on continuous or isolated. spread
Brookfield San Diego Builders, Inc.
PA-22 Robertson Ranch, East Village
File:e:\wp9\5300\5353b1.ror.pa22
GeoSoils, lne.
w.o. 5353-B1-SC
March 6, 2009
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footings (typically 18 to 30 inches below planned grades, and connect~d together in two
directions) designed in accordance with the following recommendations.
24 2.5 ksf ~.5 ksf
The above values are for dead plus live loads and may be irwreased by one-third for
short-term wind or seismic loads. Where column or wall spacings are less than twice the
width ofthe footing, some reduction in bearing capacity may be necessary to compensate
for the effects of group action. Reinforcement should be designed in accordancewith local
codes and structural considerations. .
The recommended allowable bearing capacity is generally based on maximum total and
differential settlements indicated in this report for building areas. Actual settlement can be
estimated on the basis that settlement is roughly proportional to the net contact bearing
pressure. The majority of the settlement should occur during construction. Since
settlement is a function of footing size and contact bearing pressure, some differential
settlement can be expected between adjacent columns or walls where a large differential
loading condition exists. However, for most cases, static differential settlements are
considered unlikely to those previously indicated. With increased footing depth/width
ratios, differential settlement should be less, provided the minimum fill cap is maintained
beneath all footings. GSI should review foundation plans and evaluate foundation-specific
load patterns. Based upon our review, supplemental recommendations may be necessary.
Other Footing Design Parameters
1. For lateral sliding resistance, a 0.35 coefficient of friction may be utilized for a
concrete to soil contact when multiplied by the dead load.
2. Passive earth pressure may be computed as an equivalent fluid having a density of
250 pet with a maximum earth pressure of 2,500 psf.
3. . When combining passive pressure and frictional resistance, the passive pressure
component should be reduced by one-third.
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4. Soil generated from footing excavations to be used onsite should be moisture
conditioned to at least optimum moisture content and compacted to at least
90 percent minimum relative compaction, whether it is to be ptaced in,side the
foundation perimeter or in landscape/right-of-away areas. This material must not
alter positive drainage patterns that direct drainage away from the structural area
and toward the street.
Settlement
Within the planned building area, and other areas ofthe site 4nderlain with formational soil
at depth (see Plate 1), slabs and foundations should be designed to minimally
accomnlodate an estimated 1 inch of differential settlement (angular distortion of 1/480),
in 40 feet. Within areas ofthe site underlain with alluvial soil left in place, our analysis (GSI,
2007b) indicates a recommended "waiting period" of up to 120 days to allow for the
consolidation, and settlement of the underlying alluvial soils in response to the fill loads
applied. As such, any improvement constructed in areas ofthe site underlain with alluvial
soil, and within 15 feet of the buried alluvium contact (see Plate 1), will be subject to
adverse settlement if these improvements are constructed during the "waiting period."
Settlement monitoring could be performed if desired, in order to evaluate if a shorter wait
period may be applied.
Construction
The following isolated spread and continuous footing foundation construction
recommendations are presented as a minimum criteria from a soils engineering viewpoint.
The onsite soil's expansion potential, evaluated by laboratory testing, is generally in the
low to medium (E.I. 41 to 61) range, with a P.1. of 22. Recommendations by the project's
design-structural engineer or architect, including the design of foundations for expansive
soils, per the CSC (CSSC, 2007), which may exceed the soils engineer's
recommendations, should take precedence over the following minimum requirements.
1 . Conventional continuous footings should be founded at a minimum depth of 18 to
30 inches (depending on the allowable bearing value from the previous section)
below the lowest adjacent ground surface for typical tilt-up loads. Interior footings
may be founded at a minimum depth of 18 to 30 inches below the lowest adjacent'
ground surface.
Footings should have a minimum width of 24 inches. All footings should be
reinforced with a minimum of four NO.5 reinforCing bars, two at the top and two
NO.5 reinforcing bars at the bottom.
2. Isolated exterior pier and column footings may be constructed 24 inches square by
24 inches deep, and tied to the main foundation in at least two directions with a
grade beam. Isolated footing reinforcement should be designed by the project
structural engineer.
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3.
4.
5.
6.
A grade beam, reinforced as above and at least 18 inches deep, should be provided
across garage (if proposed), or any other large entrances. The base of the
reinforced grade beam should be at the same elevation as the adjoining footings.
The slab subgrade moisture content should be at least the soil's optimum moisture
content to a depth of 18 to 30 inches below grade.
Concrete mix design and slab underlayment recommendations are provided in the
"Soil Moisture yoosiqerations" section of this report.
Concrete slab-on-grade construction recommendations are provided in the
following section.
FLOOR SLAB DESIGN RECOMMENDATIONS -ISOLATED SPREAD
AND CONTINUOUS FOOTING FOUNDATION SYSTEMS
General
Concrete slab-on-grade floor construction is anticipated. The following are presented as
minimum design parameters for the slab, but they are in no way intended to supercede
design by the structural engineer. Design parameters do not account for concentrated
loads (e.g., fork lifts, heavy rack loads, other machinery, etc.) and/or the use offreezers or
heating boxes.
These recommendations are meant as minimums. The project architect and/or structured
engineer should review and verify that the minimum recommendations presented herein
are considered adequate with respect to anticipated uses.
Light Load Floor Slabs
The slabs in areas that will receive relatively light live loads (Le., office space, less than
50 pst) should be a minimum of 5 inches thick and be reinforced with No.3 reinforcing bar
on 18-inch centers in two horizontally perpendicular directions. Reinforcing should be
properly supported to ensure placement near the vertical midpoint of the slab. "Hooking"
of the reinforcement is not considered an acceptable method of positioning the steel.
The project structural engineer should consider the use of transverse and longitudinal
control joints to help control slab cracking due to concrete shrinkage or expansion. Two
of the best ways to control this movement are: 1) add a sufficient amount of reinforcing
steel to increase the tensile strength of the slab; and 2} provide an adequate amount of
control and/or expansion joints to accommodate anticipated concrete shrinkage and
expansion. Concrete used in slab construction should have a maximum water/cement
ratio of 0.5. Transverse and longitudinal crack control joints should be spaced no more
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12 feet on center and constructed to a minimum depth of T/4, where liT" equals the slab
thickness in inches.
Heavy Load Floor Slabs
The project structural engineer should design the slabs in areas subject to high loads
(machinery, forklifts, storage racks, etc.). The Modulus of subgrade reaction (ks-value)
may· be used in the design ofthe floor slab supporting heavy truck traffic, fork lifts, machine
foundations, and heavy storage areas. A ks-value of 100 pounds per square inch per inch
(pci) would be prudent to utilize for preliminary slab design. An R-value test and/or plate
load test may be used to verify the ks-value on near-surface fill soils.
Concrete slabs should be at least 6 inches thick and reinforced with NO.4 reinforcing bars
placed 12 inches on center in two horizontally perpendicular directions. Selection of slab
thickness compatibility with anticipated loads should be provided by the structural
engineer.
Transverse and longitudinal crack control joints should be spaced no more than 14 feet
on center and constructed to a minimum depth of T/4. The use of expansion joints in the
slab should be considered. Concrete used in slab construction should have a maximum
water/cement ratio of 0.5. Spacing of expansion or crack control joints should be modified
based on the footprint of the area to be heavily loaded.
Mitigation of Water Vapor Transmission
The following methodologies for vapor transmission mitigation are provided below with
respect to the Robertson Ranch, East Village Project, are also presented in Table A. The
following minimum guidelines have been developed in accordance with the expansive
oharacter of the building pad subgrade within about 7 feet of finish grade.
Medium Expansive Soils
For floor slabs bearing on medium expansive soil subgrades (E.1. between 51 and90), the
slab should be underlain with 2 inches of sand (SE >30), over a 15-mH vapor retarder,
over a minimum 2-inch sand (SE >30) base. The minimum concrete compressive
strength should be at least 2,500 psi. The vapor retarder should comply with tlie
ASTM E 1745 -Class A or 8 criteria, and be installed in accordance with ACI 302.1 R-04
(ASTM 1643). A 2-inch layer of "pea" gravel may be sUbstituted for the sar:1d layer used
beneath the vapor retarder if it is desired to further mitigate water/water vapor transmission.
Concrete used in slab construction should have a maximum water/cement ratio of 0.5
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Other Considerations
Regardless of the soils expansion potential, an additional improvement to moisture
protection would be to extend the vapor retarder/membrane beneath all foundation
elements and grade beams. In addition, because it has been shown that the lateral
migration of water from foundation edges may contribute significantly to excess moisture
transmission, the vapor retarder/membrane could extend slightly above soils grade around
the slab/foundation perimeter and the exposed foundation face could be painted with a
latex sealer prior to color coat. Recognizing that these measures go beyond the current
standard of care, we recommend that the developer evaluate the co.nstruction issues and
costs associated with the additional measures above and determine the feasibility of
implementing them.
While these methods are considered to be overall improvements to the existing
recommendations for this project (GSI, 2004 and 2007b) , they will only minimize the
transmission of water vapor through the slab, and may not completely mitigate it. Floor
slab sealants may also be used for a particular flooring product, if necessary. The use of
concrete additives that reduce the overall permeability (water reducers) of the concrete
may also be considered. Generally, slab moisture emission rates range from about 2 to
27 Ibs/24 hours/1,000 square feet from a typical slab (Kanare, 2005), while typical floor
covering manufacturers recommend about 3 Ibs/24 hours as an upper limit Accordingly,
floor coverings and improvements that can tolerate these anticipated rates should be
considered by the developer/owner.
Subgrade Preparation
Subgrade material should be compacted to a minimum of 90 percent of the maximum
laboratory dry density. Prior to placement of concrete, the subgrade soils should be
presaturated to 18 to 30 inches below grade (depending on the footing depth utilized) to .
at least 1.2 times (120 percent of) the soil's optimum moisture content. This should be
verified by our field representative prior to visqueen placement and prior to and within
72 hours of the concrete pour. Alternative methods, including sealing the subgrade
surface with select sand/base and periodic moisture conditioning, may also be considered,
as long as the minimum recommended soil moisture contents are achieved.
POST-TENSIONED SLAB FOUNDATIONS
The recommendations presented below should be followed in addition to those contained
in the previous sections, as appropriate. The information and recommendations presented
below in this section are not meant to supercede design by a registered structural engineer
or civil engineer familiar with post-tensioned slab design. Post-tensioned slabs should be
designed using sound engineering practice and be in accordance with local and/or
national code requirements.
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From a soil expansion/shrinkage standpoint, a common contributing factor to distress of
structures using post-tensioned slabs is fluctuation of moisture in soils underlying the
perimeter ofthe slab, compared to the center, causing a "dishing" or "arching" ofthe slabs.
To mitigate this possibility, a combination of soil presaturation and construction of a
perimeter cut-off wall should be employed.
Perimeter cut-off walls should be a minimum of 18 inches deep for medium expansive
soils. The cut-off walls may be integrated into the slab design or independent of the slab
and should be a minimum of 6 inches wide. The concrete slab should be a minimum of
5 inches thick. The actual slab thickness should be determined by the project architect
and or structural engine~red based upon the anticipated loading and use. Post-tension
slab underlayment and concrete mix for post-tension slabs and beams should conform the
recommendations provided in the "Mitigation of Water Vapor Transmission" section ofthis
report. Presaturation is required for medium expansive soils. The moisture content of the
slab subgrade soils should be equal to, or greater than 1.2 times (120 percent of).the soil's
optimum moisture content to a depth of 18 inches below finish grade, and should be
verified no greater than 72 hours prior to the underlayment placement.
Post-Tensioning Institute (PTI) Method
Based on the as-built graded conditions within the subject lots, the following table in
general accordance with the CBC (CBSO, 2007) presents foundation design parameters
for post-tensioned slab foundations relative to a specific range of soil expansion potential.
Settlement criteria is provided in a previous section of this report, and GSI (2007b).
The coefficients are considered minimums and may not be adequate to represent worst
case conditions such as adverse drainage and/or improper landscaping and maintenance.
The parameters evaluated are applicable provided structures have positive drainage that
is maintained away from structures. Therefore, it is important that information regarding .
drainage, site maintenance, settlements, and effects of expansive soBs be passed on to
future owners.
Based on the parameters evaluated, and the CBC (CBSC, 2007) the following design
values are presented. The values may not be appropriate to account for possible
differential settlement of the slab due to other factors. If a stiffer slab is desired, higher
values of ym may be warranted.
em center lift 8.7 feet
em edge lift 4.5 feet
Ym center lift 0.49 inches
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Ym edge lift 1.3 inch
Bearing Value (1) 1,000 pst
Lateral Pressure 250 pst
Subgrade Modulus (k) 85 pci/inch
Minimum Perimeter
I-rnll")<>r1lrn<>nT (2) 24 inches
(1) Internal bearing values within the perimeter of the post-tension slab may
increased to 2,000 psf for a minimum embedment of 12 inches, then by 20
percent for each additional foot of embedment to a maximum of 3,000 pst.
(2) As measured below the lowest adjacent compacted subgrade surface.
Note: The use of open bottomed raised planters adjacent to foundations will '
The bottom of the deepened footing/edge should be designed to resist tension, using
cable or reinforcement per the structural engineer. Other applicable recommendations
presented under conventional foundation and the California Foundation Slab Methoo
should be adhered to during the design and construction phase of the project.
SETBACKS
All settlement-sensitive improvements should maintain a minimum hQrizontal setback of
H/3 (H=slope height) from the base ofthe footing to the descending slope face of no less
than 7 feet, nor need not be greater than 40 feet. This distance is measured from the
improvement or footing face at the bearing elevation. Footings adjacent to, unlined
drainage swales should be deepened to a minimum of 6 inches below the invert of th'e
adjacent unlined swale. Footings for structures adjacent to retaining walls shOUld be
deepened so as to extend berow a 1: 1 projection from the heel of the wall. Alternatively,
WaHs may be designed to accommodate structural loads from buildings or appurtenances,
as described in the "Retaining Wall" section of this report.
SOLUBLE SULFATES/RESISTIVITY
Based on our testing and experience in the vicinity, the majority of site soils are anticipated
to have a negligible sulfate exposure to concrete per Table 4.2.1 and 4.3.1 of ACI318-08,
ahd the 2007 CBC. Site soils are also anticipated to be very corrosive to buded metal.
This level of corrosion was evaluated by saturated resistivity test(s). As such, the amount
,of soil will influence the variation in soil corrosivity to exposed/buried metal improvements.
Consultation with a corrosion engineer is recommended, by the designer, and/or
developer.
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WALL DESIGN PARAMETERS
Conventional Retaining Walls
Retaining walls should be designed in accordance with the CBC (CBSC, 2007). The
design parameters provided below assume that either non-expansive soils (Class 2
permeable filter material or Class 3 aggregate base) or native materials (up to and
including an E.1. of 50) are used to backfill any retaining walls. The type of backfill (Le.,
select or native), should be specified by the wall designer, and clearly shown on the plans.
Building walls, below grade, should be water-proofed. The foundation system for the
proposed retaining walls should be designed in accordance with the recommendations
presented in this and preceding sections of this report regarding conventional foundation
design, as appropriate. The bottom of footings should be embedded a minimum of
18 inches below adjacent grade (excluding landscape lay~r, 6 inches) and should b.e
24 inches in width. There should be no increase 'in bearing for footing width.
Recommendations for specialty walls (Le., crib, earthstone, geogrid, etc.) can be provided
upon request, and would be based on site specific conditions.
Restrained Walls
Any retaining walls that will be restrained prior to placing and compacting backfill material
or that have re-entrant or male corners, should be designed for an at-rest equivalent fluid
pressure (EFP) of 100 pcf (native soil) or 60 pcf (select), plus any applicable surcharge
loading, per Table 1610.1 of the CBC (CBSC, 2007) for USCS soil classification SM-SC.
For areas of male or re-entrant corners, the restrained wall design should extend a
minimum distance of twice the height of the wall (?H) laterally from the corner.
Cantilevered Walls
The recommendations presented below are for cantilevered retaining walls up to 10 feet
high. Design parameters for walls less than 3 feet in height may be superceded by City
and/or County standard design. Active earth pressure may be used for retaining wall
design, provided the top of the wall is not restrained from minor deflections. An equivalent
fluid pressure approach may be used to compute the horizontal pressure against the wall.
Appropriate fluid unit weights are given below for specific slope gradients of the retained
material. These do not include other superimposed loading conditions due to traffic,
structures, seismic events or adverse geologic conditions. When wall configurations are
finalized, the appropriate loading conditions for superimposed loads can be provided upon
request. Traffic load surcharges should be applied within a distance 'H' in feet behind the
wall, where 'H' is the height of the wall. Earthquake loads need only be applied for walls
that are 6 feet or more of retained earth and/or will impede access to, and ,from, the
building, or the project site.
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* Level backfill behind a retaining wall is defined as compacted earth materials, properly drained,
. without a slope for a distance of 2H behind the wall.
** SE >30 and <10 percent passing No. 200 sieve.
*** E.1. <50, SE >20, and PI <15.
Values
Retaining Wall Backfill and Drainage
Positive drainage must be provided behind aU retaining walls in the form of gravel wrapped . .
in geofabric and outlets. A backdrain system is considered necessary fOr" retaining walls
that are 2 feet or greater in height. Sackdrains should consist of a 4-inch diameter
perforated PVC or ASS pipe encased in either Class 2 permeable filter material or 1h-inch
to %-inch gravel wrapped in approved filter fabric (Mirafi 140 or equivalent). For low
expansive backfill, the filter material should extend a minimum of 1 horizontal foot behind
the base of the walls and upward at least 1 foot. For native backfill that has up to medium
expansion potential, continuous Class 2 permeable drain materials, or 1h-inch to %-inch
gravel wrapped in approved filter fabric (Mirafi 140, or equivalent) should be used behind
the wall as backfill within the active zone, defined as the area above a 1:1 projection up
from the base ofthe wall stem. This material should be continuous (Le., full height) behind
the wall. The surface of the backfill should be sealed by pavement or the top 18 inches
compacted to 90 percent relative compaction with native soil. For limited access and
confined areas, (panel) drainage behind the wall may be constructed. Materials with an
E.I. potential of greater than 65 should not be used as backfill for retaining walls,
regardless of the criteria for backfill summarized in the preceding table. Any wall drainage
plan should be reviewed by this office for approval prior to construction. Wall backfill
should be made by relatively light equipment. The contractor should avoid stockpiling
earth or any building material within 2H of newly completed/backfilled walls, where H is the
height of the wall, in feet.
Weeping of the walls in lieu of a backdrain is not recommended for walls greater than
2 feet in height. For walls 2 feet, or less, in height, weepholes should be no greater than
6 feet on center in the bottom coarse of block and above the landscape zone. Outlets
should consist of a 4-inch diameter solid PVC or ASS pipe spaced no greater than
+ 1 00 feet apart, with a minimum of two outlets, one on each end. The use of only weep.
holes in walls higher than 2 feet should not be considered. The surface of the backfill
should be sealed by pavement or the top 18 inches compacted with native soil (E.!. <50).
Proper surface drainage should also be provided. For additional mitigation, consideration
should be given to applying a water-proof membrane to the back of all retaining structures.
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The use of a waterstop should be considered for all concrete and masonry joints. Proper
surface drainage should also be provided in order to reduce the potential for surface water
penetration.
Wall/Retaining Wall Footing Transitions
Site walls are antiCipated to be founded on footings designed in accordance With the
recommendations in this report. Should wall footings transition from cut to fill, the civil
designer may specify either:
a) A minimum of a 2-foot overexcavation and recompaction of cut materials for a
distance of 2H, from the point of transition.
b) Increase ofthe amount of reinforcing steel and wall detailing (Le., expansion joints
or crack control joints) such that a ~ngular distortion of 1/360 for a distance of 2H
on either side ofthe transition may be accommodated. Expansion joints should be
placed no greater than 20 feet on-center, in accordance with the structural
engineer's/wall designer's recommendations, regardless of whether or nottransition
conditions exist. Expansion joints should be sealed with a flexible, non-shrink grout.
.c) Embed the footings entirely into native formational material (Le., deepened
footings).
If transitions from cut to fill transect the wall footing alignment at an angle of less than
45 degrees (plan view), then the designer should follow recommendation "a" (above) and
until such transition is between 45 and 90 degrees to the wall alignment. The presence of
transitions beneath planned improvements with result in an elevated potential for distress
to the particular improvement, . unless the recommendations presented above are
implemented.
TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS
Due to the potential for slope creep (see the "Development Criteria" secti.on for a
discussion) for slopes higher than about 10 feet, some settlement and tilting of the
walls/f~nce with the corresponding distresses, should be expected. To mitigate thetilting
of top of slope walls/fences, we recommend that the walls/fences be constructed on
deepened foundations without any consideration for creep forces, where the expansion
index of the materials comprising the outer 15 feet of the slope is less than 50, or a
combination of grade beam and caisson foundations, for expansion indices greater than
50, comprising the slope, with creep forces taken into account.,. Recommendations for
grade beam and caisson foundations can be provided upon request. Deepened
foundations should minimally provide for a lateral distance of 7 f~et from the outside
bottom edge of the footing to the face of slope and provide enough lateral resistance for
creep forces. Site soils are considered to have an EJ. of greater than !)O.
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DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS
The effects of expansive soils are cumulative, and typically occur over the lifetime of any
improvements. On relatively level areas, when the soils are allowed to dry, the dessication
and swelling process tends to cause heaving and distress to flatwork and other
improvements. The resulting potential for distress to improvements may be reduced, but
not totally eliminated. To reduce the likelihood of distress, the following recommendations
are presented for all exterior flatwork:
1 . The subgrade area for concrete slabs should be compacted to achieve a minimum
90 percent relative compaction. If very low to low expansive soils are present, only
,optimum moisture content, or greater, is required and specific presoaking is not
warranted. For medium, or higher expansive soils, the subgrade should be
presoaked to 2 to 3 percentage points above (or 125 percent of) the soils' optimum
moisture content, to a depth of 12 inches below subgrade elevation. The moisture
content of the subgrade should be evaluated by the geotechnical consultant within
72 hours prior to pouring concrete.
2.
3.
4.
Concrete slabs should be cast over a non-yielding surfac~, consisting of a 4-inch
layer of crushed rock, gravel, or clean sand, that should be compacted and level
prior to pouring concrete. If very low to low expansive soils are present, the. rock
or gravel or sand is not required. The layer or subgrade should be wet-down
completely prior to pouring concrete, to minimize loss of concrete moisture to the
surrounding earth materials. Cut/fill transitions should be mitigated beneath any
settlement sensitive improvement. The adverse effects of transitions may be
mitigated by undercutting the cut portion of the transition at least 2 feet below the
grade, and replacing with compacted fill.
Exterior slabs should be a minimum of 4 inches thick. When driveways are placed
over rock, gravel or clean sand, driveway slabs and approaches should-additionally
have a thickened edge which isolates the bedding material from any adjacent
landscape area, to help impede infiltration of landscape water under the slab.
The use of transverse and longitudinal control joints are recommended to help
control slab cracking due to concrete shrinkage or expansion. IWO ways to
mitigate such cracking are: a) add a sufficient amount of reinforcing steel,
increasing tensile strength of the slab; and, b) provide an adequate amount of
control and/or expansion joints to accommodate anticipated concrete shrinkage
and expansion.
In order to reduce the potential for unsightly cracks, exterior slabs may be
reinforced with NO.3 reinforcing bars, 18 inches on center; each way. The ext~rior
slabs should be scored or saw cut, to a minimum depth of T/4, where "T" is the
thickness ofthe slabs in inches. Saw cuts should be provided often enough so that
no section is greater than 10 feet by 10 feet. For sidewalks or narrow slabs, control
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joints should be provided at intervals of every 6 feet. The slabs should be separated
from the foundations and sidewalks with expansion/shrinkage joint filler material.
5. No traffic should be allowed upon the newly poured concrete slabs until they have
been properly cured to within 75 percent of design strength. Concrete compression
strength should be a minimum of 2,500 psi.
6. Driveways, sidewalks, and patio slabs adjacent to a structure should be separated
from the structure with expansion/shrinkage joint filler material. . In areas directly
adjacent to a continuous source of moisture (Le., irrigation, planters, etc.), all joints
should be additionally sealed with flexible mastic.
. .
7. Planters and walls should not be tied to the structure.
8. Overhang structures should be supported on the slabS, or structurally designed
with continuous footings tied in at least two directions. If very low expansion soils
are present, footings need only be tied in one direction.
9. Any masonry landscape walls that are to be constructed throughout the property
should be grouted and articulated in segments no more than 20 feet long. These
segments should be keyed or doweled together.
10. Utilities should be enclosed within a closed utilidor (vault) or designed with flexible
connections to accommodate differential settlement and expansive soil conditions.
11. Positive site drainage should be maintained at all times. Finish grade on the p~ds
should provide for an adequate fall to the street, per the design. civil engineer. It
should be kept in mind that drainage reversals could occur, including
post-construction settlement, if relatively flat yard drainage gradients are not
periodically maintained by the owner or owners association.
12. Air conditioning (NC) units should be supported by slabs that are incorpor;.:1ted into
the building foundation, or constructed on an isolated rigid slab with flexible
couplings for plumbing and electrical lines. A/e waste water lines should be
drained to' a suitable outlet.
13. Shrinkage cracks could become excessive if proper finishing .and curing practices
are not followed. Finishing and curing practices should be performed per the
Portland Cement Association Guidelines. Mix design should if1corpor~te rate of
curing for climate and time of year, sulfate content of soils, corrosion potential of
soils, and fertilizers used on site. If spray on typical curing is employed, apply as
soon as possible after finishing. Use Hunt's curing compound, or equivalent.
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PRELIMINARY PAVEMENT DE~IGN
Preliminary pavement section design was performed in general accordance with the
California Department of Transportation (Caltrans) Highway Design Manual of Instructions
(2006), traffic index data provided by the project civil engineer, and the minimum sections
per the City. Pavement sections are based on the aforementioned criteria, the City of
Carlsbad (1993) design criteria, and the resistance R-value data estimated for the area.
Parking Lot Stalls 4.5
Traffic Areas 5.0
15
15
3.0
4.0
3.0
4.0
7.0
5.0
9.0
7.0
Final pavement sections shall be based on site specific R-value testing upon completion
of underground improvements. Pavements for trash enclosures should be designed per
the City standard. All pavement construction should be performed in accordance with the
currently approved. and applicable specifications, and the standard of practice. ' Best
management Gonstruction practices should be followed at all times, especially durihg
inclement weather. Due to the relatively low R-value{s) of the soil samples obtained from
finished subgrade, GSI recommends that drainage of the subgrade and provisions for
irrigation and other water should not be allowed to penetrate street subgrades. GSI will
assist the civil designer to reduce this potential.
Slope Deformation
General
I
DEVELOPMENT CRITERIA ,
\ ,
Compacted fill slopes, designed using customary factors of safety for gross or sl;Jrficial
stability, and constructed in general accordance with the design, specifications, should be
expected to undergo some differential vertical heave, or settlement, in combination
with differential lateral movement in the out-of-slope direction, after grading. This
post-construction movement occurs in two forms: slope creep; and, lateral fill extension
(LFE).
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Slope Creep
Slope creep is caused by alternate wetting and drying of the fill soils which results in slow
downslope movement. This type of movement is expected to occur throughout the life of
the slope, and is anticipated to potentially affect improVements or structures (Le.,
separations and/or cracking), placed near the top-of-slope, generally within a horizontal
distance of approximately 15 feet, measured from the outer, deepest (bottom outside)
edge of the improvement, to the face of slope. The actual width of the zone affected is
generally dependant upon: 1) the height ofthe slope; 2) the amount of irrigation/rainfall the
slope receives; and, 3) the type of materials comprising the slope. This movement
generally results in rotation and differential settlement of improvements located within the
creep zone.
Suitable mitigative measures to reduce the potential for distress due to lateral deformation
typically include: setback of improvements from the slope faces (per the 2007 CSC);
positive structural separations (Le., joints) between improvements; and, stiffening c;lhd
deepening of foundations. Per Section 1805.3.1 of the 2007 CSC, 'a horizontal setback
(measured from the slope face to the outside bottom edge of the building footing) of H/3
is provided for structures, where H is the height of the fill slope in feet, and H/3 (to be
minimally 7 feet), need not be greater than 40 feet. Alternatively, in consideration of the
discussion presented above, site conditions and Section 1805.3.1 of the 2007 CSC, H/3
generally need not be greater than 20 feet for the development. As an alternative to a
deepened footing, where the adjacent slope is greater than 45 feet in height and the
building/footing is within 20 feet from the slope face, a differential settlement of 0.5 inch
(additional) may be applied to the design of that portion of the structure(s). Any
settlement-sensitive improvements (Le., walls, spas, flatwork, etc.) should minirnally
consider the above.
Lateral Fill Extension (LFE)
LFE occurs due to deep wetting from irrigation and rainfall on slopes compri$ed of
expansive materials. Sased on the generally very low expansive character of onsite soils,
the potential component of slope deformation due to LFE is considered minor, but may not
be totally precluded. Although some movement should be expected, long-term movement
from this source may be minimized, but not eliminated, by generally placing the fill
throughout the slope region, wet of the fill's optimum moisture content, as was done on
this project. '
Summary
It is generally not practical to attempt to eliminate the effects of either slope creep or LFE.
Suitable mitigative measures to reduce the potential of lateral deformation typically include:
setback of improvements from the slope faces (per the CSC [CSSC, 2007]); positive
structural separations (Le., joints) between improvements; stiffening; and, deepening of
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foundations. All of these measures are recommended for design of structures and
improvements and minimizing the placement of "dry" fills.
Slope Maintenance and Planting
Water has been shown to weaken the inherent strength of all earth materials. Slope
stability is significantly reduced by overly wet conditions. Positive surface drainage, away ,
from slopes, should be maintained and only the amount of irrigation necessary to sustain
plant life should be provided for planted slopes. Over-watering should be avoided as it can
adversely affect site improvements and cause perched, grou'ndwater conditions. Graded
slopes constructed utilizing onsite materials would be erosive. Eroded debris may be
mioimized and surficial slope stability enhanced by establishing and maintaining asuitable
vegetation cover soon after construction. Compaction to the face offill slopes would tend
to minimize short-term erosion until vegetation is established. Plants select~d for
landscaping should be light weight, deep rooted types that require little water and are
capable of surviving the prevailing climate. Jute-type matting, or other fibrous covers, may
aid in allowing the establishment of a sparse plant cover. Utilizing plants other than those
recommended above will increase the potential for perched water, staining, mold" etc. to
develop. A rodent control program to prevent burrowing should be implemented.
Irrigation of natural (ungraded) slope areas is generally not recommended.
Over-steepening, of slopes should be avoided during building construction activities and
landscaping. All landscaping plans should be reviewed by a qualified civil engineer with
respect to site drainage and compatibility with adjoining property uses.
Drainage
Adequate pad surface drainage is a very important factor in reduCing the likelihood of
adverse performance offoundations, hardscape, and slopes. Surface drainage should be
sufficientto prevent ponding of water anywhere on a lot, and especially near structures and
tops of slopes. Pad surface drainage should be carefully taken into consideration during
fine grading, landscaping, and building construction. Therefore, care should be taken that
future landscaping or construction activities do not create adverse drainage conditions. . ,
Positive site drainage within pads and common areas should be provided and maintained
at all times. Drainage should not flow uncontrolled down any descending slope. Water
should be directed away from foundations and not allowed to pond and/or seep into the
ground. In general, the area within 3 feet around a structure should slope away from the
structure. We recommend that unpaved lawn and landscape areas have a minimum
gradient of 1 percent sloping away from structures, and whenever possible, should be
above adjacent paved areas. Consideration should be given to avoiding construction of
raised planters adjacent to structures (buildings, pools, spas, etc.). Pad drainage should
be directed toward the street or other approved area(s). Although not a geotechnica]
requirement, roof gutters, down spouts, or other appropriate means may be utilized to
control roof drainage. Down spouts, or drainage devices, should outlet a minimum of
3 feet from structures or into an alternate, approved area, such ,as a drainage system
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swale. Areas of seepage may develop due to irrigation or heavy rainfall, qnd should be
anticipated. Minimizing irrigation will lessen this potential. If areas of seepage develop,
recommendations for minimizing this effect could be provided upon request. Geotechnical.
recommendations for drainage practices are included herein. The civil consultant and
landscape planner(s) should provide additional recommendations in accorda.nce with local
practices.
Erosion Control
Cut and fill slopes will be subjectto surficial erosion during and after grading. Onsite ,earth
materials have a moderate to high erosion potential. Consideration should be given to
providi.ng hay bales and silt fences for the temporary control of surface water, from a
geotechnical viewpoint.
Landscape Maintenance
Only the amount of irrigation necessary to sustain plant life should be provided.
Over-watering the landscape areas will adversely affect proposed site improvements. We
recommend that any open-bottom, raised box planters adjacent to proposed structures
be restricted for a minimum distance of 10 feet. As an alternative, closed-bottom type
raised planters could be utilized. An outlet placed in the bottom of the planter could be
installed to direct drainage away from structures or any exterior concrete flatwork. If raised
box planters are constructed adjacent to structures, the sides and bottom of the planter
should be provided with a moisture retarder to prevent penetration of irrigation water into
the subgrade. Provisions should be made to drain the excess irrigation water from the
planters without saturating the subgrade below or adjacent to the planters. Graded slope
areas should be planted with drought resistant vegetation. Consideration should be
given to the type of vegetation chosen and their potential effect upon surface
improvements (Le., some trees will have an effect on concrete flatwork with their extensive
root systems). From a geotechnical standpoint, leaching is not recommended for
establishing landscaping. If the surface soils are processed for the purpose of adding
amendments, they should be recompacted to 90 percent minimum relative compaction.
Subsurface and Surface Water
Subsurface and surface water are not anticipated to affect site development, provided the
recommendations contained in this report are incorporated into final design and
construction, and that prudent surface and subsurface drainage practices are incorporated
into the construction plans. Perched groundwater conditions, along zones of contrasting
permeabilities, may not be precluded from occurring in the future due to site irrigation,
poor drainage conditions, or damaged utilities, and should be anticipated. Should
perched groundwater conditions develop, this office could assess the affected area,(s) and
provide the appropriate recommendations to mitigate the observed groundwater
conditions. Groundwater conditions may change with the introduction of irrigation, rainfall,
or other factors.
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Tile Flooring
Tile flooring can crack, reflecting cracks in the concrete slab below the tile, although small
cracks in a conventional slab may not be significant. The tile installer should consider
installation methods that reduce possible cracking of the tile such as slipsheets, a vinyl
crack isolation membrane, or other approved method by the Tile Cour:Jcil of
America/Ceramic Tile Institute.
Site Improvements
If in the future, any additional improvements (e.g., pools, spas, etc.) are planned 'for the
site, recommendations concerning the geological or geotechnical aspects of design and
construction of said improvements could be provided upon request. Pools and/or spas
should not be constructed without specific design and construction recommendations from
GSI, and this construction recommendation should be provided to the owners association
or other interested/affected parties. This office should be notified in advance of any filL
placement, grading of the site, or trench baCkfilling after rough grading has been
completed. This includes any grading, utility trench and retaining wall backfills, flatwork,
etc.
Oversize material placed during mass grading will be encountered during trenching
operations. As such, difficult excavation should be anticipated locally. Trenches exposing
rocky, and/or oversize material will likely be required to be "laid back" at gradients on the
order of 1: 1 (h:v) to improve slope stability. Trench spoils containing oversize material (Le.,
greater than 8 to 12 inches in long dimension) will not be suitable for use as backfill, and
should be removed from the site.
Additional Grading
This office should be notified in advance of any fill placement, supplemental regrading of
the site, or trench backfilling after rough grading has been completed. This includes
completion of grading in the street and parking areas and utility trench and retaining wall
backfills. Rough grading is generally completed in areas shown on Plate 1, excluding the
RV lot and parking areas south of the lot.
Footing Trench Excavation
All footing excavations should be observed by a representative of this firm subsequent to
trenching and prior to concrete form and reinforcement pla~ement. The purpose of the
observations is to verify that the excavations are made into the recommended bearing
material and to the minimum widths and depths recommended for construction. If loose
or compressible materials are exposed within the footing excavation, a deeper footing or
removal and recompaction of the subgrade materials would be recommended at that time.
Footing trench spoil and any excess soils generated from utility trench excavations should
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be compacted to a minimum relative compaction of 90 percent, if not removed from the
site.
Trenching
Considering the nature of the onsite soils, it should be anticipated that caving or slbughing
could be a factor in subsurface excavations and trenching. Shoring or excavating the
trench walls at the angle of repose (typically 25 to 45 degrees) may be necessary and
should be anticipated. All excavations should be observed by one of our repr:~sentatives
and minimally conform to Cal-OSHA and local safety codes.
Utility Trench Backfill
1.
2.
3.
4.
5.
All interior utility trench backfill should be brought to at least 2 percent above
optimum moisture content and then compacted to obtain a minimum relative
compaction of 90 percent of the laboratory standard. As an alternative for shalloW
(12-inch to 18-inch) under-slab trenches, sand having a sand equivalent value' of
30 or greater may be utilized and jetted or flooded into place. Observation, probing
and selective testing should be provided to evaluate the desired results.
Exterior trenches adjacent to, and within areas extending below a 1: 1 plane
projected from the outside bottom edge of the footing, and all trenches beneath
hardscape features and in slopes, should be compacted to at least 90 percent of
the laboratory standard. Sand backfill, unless excavated from the trench, should
not be used in these backfill areas. Selective compactioA testing and observations,
along with probing, should be accomplished to verify the desired results.
All trench excavations should conform to Cal-OSHA and local safety codes.
Utilities crossing grade beams, perimeter beams, or footings should either pass
below the footing or grade beam utilizing a hardened col/ar or foam spacer, or pass
through the footing or grade beam in accordance with the recommendations of the
structural engineer.
Oversize material placed during mass grading will be encountered during trenching
operations. As such, difficult excavation should be anticipatedlocal/y. Trenches
exposing rocky, and/or oversize material will likely be required to be "laid back" at
gradients on the order of 1:1 (h:v) to improve slope stability. Trench spoils
containing oversize material (Le., greater than 8 to 12 inches in long dimension) will
not be suitable for use as backfill, and should be removed from the site.
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SUMMARY OF RECOMMENDATIONS REGARDING
GEOTECHNICAL OBSERVATION AND TESTING
We recommend that observation and/or testing be performed by GSI at each of the
following construction stages:
•. During grading/recertification.
• After excavation of building footings, retaining wall footings, and free standing walls
footings, prior to the placement of reinforcing steel or concrete.
•
•
•
•
•
•
•
•
Prior to pouring any slabs or flatwork, after presoaking/presaturation of building
pads and other flatwork subgrade, before the placement of concrete, reinforcing
steel, capillary break (Le., sand, pea-gravel, etc.), or vapor retarders (Le., visqt.leen,
etc.), as necessary.
During retaining wall subdrain installation, prior to backfill placement.
During placement of backfill for area drain, interior plumbing, utility line' trenches,
and retaining wall backfill, as necessary.
During slope construction/repair.
When any unusual soil conditions are encountered during any construction
operations, subsequent to the issuance of this report.
When any developer or owner improvements, such as flatwork, spas, pools, vyalls,
etC., are constructed.
A report of geotechnical observation and testing and/or field testing reports, should
be provided at the conclusion of each of the above stages as necessary, in order
to provide concise and clear documentation of site work, and/or to comply with
code requirements. .
,
GSI should review project sales documents to owners/owners associations for
geotechnical aspects, including irrigation practices, the conditions outlined above,
etc., prior to any sales. At that stage, GSI will provide owners maintenance
guidelines which should be incorporated into such documents.
Brookfield San Diego Builders, Inc.
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OTHER DESIGN PROFESSIONALS/CONSULTANTS
The design civil engineer, structural engineer, post-tension designer, architect, landscape
architect, wall designer, etc., should review the recommendations provided herein,
incorporate those recommendations into all their respective plans, and by 'explicit
reference, make this report part of their project plans. This report presents minimum
design criteria for the design of slabs, foundations and other elements.possibly applicable
to the project. These criteria should not be considered as SUbstitutes for actual designs
by the structural engineer/designer. The structural engineer/designer should analyze
actual soil-structure interaction and consider, as needed, bearing, expansive soil influence,
and strength, stiffness and deflections in the various slab, foundation, and other elements
in order to develop appropriate, design-specific details. As conditions dictate,it is possible
that other influences will also have to be considered. The structural engineer/designer
should consider all applicable codes and authoritative sources where needed. If analyses
by the structural engineer/designer result in less critical details than are provided herein
as minimums, the minimums presented herein shOUld be adopted. It is considered likely
that some, more restrictive details will be required. Ifthe structura:I engineer/designer has
any questions or requires further assistance, they should not hesitate to call or otherwise
transmittheir requests to GSI. In order to mitigate potential distress, the foundation and/or
improvement's designer should confirm to GSI and the governing agency, in writing, that
the proposed foundations and/or improvements can tolerate the amount of differential
settlement and/or expansion characteristics and design criteria specified herein.
OWNERS/OWNERS ASSOCIATIONS
It is recommended that the developer should notify, and/or make available the fil1dings,
conclusions and recommendations presented in this report to any owners or owners
association, in order to minimize any misunderstandings regarding the design and
performance of earth structures, and the design and performance of existing and/or future
or proposed improvements.
PLAN REVIEW
Any additional project plans generated for this project should be reviewed by this office,
prior to construction, so that construction is in accordance with the conclusions and
recommendations of this report.
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LIMITATIONS
The materials encountered on the project site and utilized for our analysis are believed
representative ofthe area; however, soil and bedrock materials vary in character between
excavations and natural outcrops or conditions exposed during mass grading. Site
conditions may vary due to seasonal changes or other factors.
Inasmuch as our study is based upon our review and engineering analyses and laboratory
data, the conclusions and re~ommendations are professional opinions. These opinions
have been derived in accordance with current standards of practice, and no warranty,
either express or implied, is given. Standards of practice are subject to change with time.
GSI assumes no responsibility or liability for work or testing performed by others, or their
inaction; or work performed when GSI is not requested to be onsite, to evaluate if our
recommendations have been properly implemented. Use of this report constitutes an
agreemeht and consent by the user to aU the limitations outlined above, notwithstanding
any other agreements that may be in place. In addition, this report may be subject to
review by the controlling authorities. Thus, this report brings to completion our scope of
services for this portion ofthe project. All samples will be disposed of after 30 days, unless
specifically requested by the Client, in writing.
Brookfield San Diego Builders, Inc.
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The opportunity to be of service is sincerely appreciated. If you should have any
questions, please do not hesitate to call our office.
Respectfully submitted ------
Engineering G
Reviewed by:
RGC/DWS/JPF/jh
Attachments: Table 1 -Field Density Test Results
Appendix -References
Plate 1 -Geotechnical Map
Distribution: (2) Addressee
(2) O'Day Consultants, attention: Mr. Pat O'Day
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Table 1
FIELD DENSITY TEST RESULTS
699 6/26/07 Lot 3 West PA-22 38.0 14.0
700 6/27/07 Lot 3 West PA-22 38.0 13.2
701 6/27/07 Lot 3 West PA-22 40.0 14.7
702 .6/27/07 Lot 3 West PA-22 42.0 12.8
703 6/27/07 Lot 3 West PA-22 37.0 13.1
713 6/28/07 Lot 3 Central PA-22 40.0 13.9
714 fi/28/07 N Lot 3 Central PA-22 42.0 14.6
715 6/28/07 N Lot 3 Central PA-22 39.0 13.7
716 6/28/07 N Lot 3 Central PA-22 40.0 14.1
717 6/28/07 N Lot 3 Central PA-22 40.0 13.7
726 6/29/07 Lot 3 Central PA-22 40.0 13.0
727 6/29/07 Lot 3 NE PA-22 42.0 12.7
728 6/29/07 Lot 3 NE PA-22 44.0 13.2
729 6/29/07 Lot 3 East PA-22 46.0 12.6
730 6/29/07 Lot 3 Central PA-22 48.0 12.8
738 7/2/07 SLot 3 Central PA-22 44.0 12.7
739 7/2/07 Lot 3 Central PA-22 46.0 13.9
740 7/2/07 E Lot 3 Central PA-22 48.0 13.0
741 7/2/07 Lot 3 Central PA-22 49.0 14.2
752 7/3/07 Lot 3 Central PA-22 42.0 12.5
753 7/3/07 SLot 3 Central PA-22 44.0 12.5
754 7/3/07 Lot 3 SE PA-22 40.0 12.7
1167 10/15/07 Parcel 2 PA-22 40.0 9.3
1168 10/15/07 Parcel 2 PA-22 40.0 8.7
1169 10/15/07 Parcel 2 PA-22 42.0 8.0
1170 10/15/07 Parcel 2 PA-22 42.0 8.4
1171 10/15/07 Parcel 2 PA-22 44.0 8.0
1172 10/15/07 Parcel 2 PA-22 44.0 9.0
1187 10/16/07 Parcel 2 PA-22 45.0 8.5
1188 10/16/07 Parcel 2 PA-22 46.0 9.0
1189 10/16/07 Lot 3 NE PA-22 50.0 8.9
1190 10/16/07 Parcel 2 PA-22 48.0 8.1
1191 10/16/07 Lot 3 NE PA-22 50.0 8.0
1198 10/17/07 Lot 3 NE PA-22 52.0 9.0
1199 10/17/07 Lot 3 NE PA-22 50.0 8.5 .
1200 10/17/07 Lot 3 NE PA-22 52.0 8.2
1201 10/17/07 Lot 3 NE PA-22 53.0 8.9
1202 10/17/07 Lot 3 NE PA-22 52.0 8.2
1203 10/17/07 Lot 3 NE PA-22 52.0 8.7
1207 10/18/07 Lot 3 NE PA-22 52.0 8.5
1208 10/18/07 Parcel 2 PA-22 46.0 9.3
1209 10/18/07 Parcel 2 PA-22 48.0 9.0
1210 10/18/07 N Lot 3 Central PA-22 50.0 8.9
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110,0 . 91.0 NP J
110~3 91 .. 2 NO J
109.5 90.5 SC J
110.2 91.1 NO j
110.4 91.2 NO J
111.1 91.8 NO J
110.2 91 .. 1 SC J
110.4 91.2 No J
110.6 91.4 NO J
111.0' 91:7 NO J
110.3 91.2 .SC J
110.0 90.9 NO J
110.7 91.5 NO J
109:8 90.7 NO J
111,1 91.8 ND J
110.4 91.2 NO J
109.7 '90.7 SC J
1.10.1. 91.0 NO J
110.0 90.~ NO J
10~.7 90.7 NO J
110~8 91.6 NO J
110.0 90 .. 9 NO J
135.0 93.7 NO 00
135.6 94.1 NO 00
136~5 94.7 NO _ DO
136.1 94.5 S~ 00.
136.9 95:0 NO 00
. 135.3 93.9 NO . 00
135.9 94.3 No DO
135.2 93.8 NO 00
135.4 94.0 . ND 00
136.3 94.6 SC DO
136.5 94.7 NO 00
134.8 93.6 NO DO
135,4 94.0 NO 00
135.9 94.3 SC 00
134.9 93.6 ND DO
136.0 94.4 NO 00
135.2 93.!;1 ND DD'
136.4 94.7 NO 00
135.1 93~8 ND DO
135.5 94.0 SC 00
135.6 94.1 . NO. DO
W.O. 5353-B1-SC
March 2009
Page 1
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Table 1
FIELD DENSITY TEST RESULTS
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Brookfield San Diego Builders, Inc.
PA-22 Robertson Ranch, East Village
File: C:\excel\tables\5300\5353b1.ror.pa22
Table 1
FIELD DENSITY TEST RESULTS
GeoSoils,lne.
w.o. 5353-B1-SC
March 2009
P!3.ge3
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Table 1
FIELD DENSITY TEST RESULTS
LEGEND:
I = Repeated Test Number
BT = Bottom Test
ND = Nuclear Densometer
S = Slope Test
SC = Sand Cone
SF = Slope Face Test
Brookfield San Diego Builders, Inc.
PA-22 Robertson Ranch, East Village
File: C:\excel\tables\5300\5353b1.ror.pa22
GeoSoils, Ine.
w.o. 5353-B1-SC
March 2009
Page 4
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APPENDIX
REFERENCES
American Concrete Institute, 2008, Building code requirement for structural concrete
(ACI 318-08) and commentary, an ACI standard reported by ACI Committee 318,
dated January.
__ ,2004, Guide for concrete floor and slab construction: reported by ACI Committee
302; Designation ACI 302.1 R-04, dated March 23.
American Society for Testing and Materials, 1998, Standard practice for installation of
water vapor retarder used in contact with earth or granular fill under concrete slabs,
Designation: E 1643-98 (Reapproved 2005).
__ , 1997, Standard specification for plastic water vapor retarders used in contact with
soil or granular fill under concrete slabs, Designation: E 1745-97 (Reapproved
2004).
California Building Standards Commission, 2007, California building code~
Caltrans, 1999, Interim corrosion guideline for foundation investigations, Corrosion and
Technology Section, Office of Materials and Foundations, dated May.
Carlsbad, City of, 1993, Standards for design and construction of public works
improvements in the City of Carlsbad.
GeoSoils, Inc., 2008, Geotechnical update of seismic design criteria for Robertson Ranch,
East Village, City of Carlsbad, San Diego County, California, W.O. 5353-B-SC, dated
'March 17.
__ , 2007a, Compaction report of geotechnical observation and testing services, 84-ioch
storm drain improvements for Cannon Road, Robertson Ranch East Village,
Carlsbad, San Diego County, California, Carlsbad, San Diego County, California,
W.O. 5355-D-SC, dated August 16.
__ , 2007b, Updated geotechnical evaluation of the Robertson Ranch, East Village
Development, Carlsbad Tract 02-16, Drawing 433-6, Carlsbad, San Diego County,
California, W.O. 5353-A-SC, dated January 15. '
__ , 2006a, Supplemental recommendations regarding pier supported bridge
abutments, Robertson Ranch East Project, City of Carlsbad, San Diego County,
California, W.O. 3098-A2-SC, dated November 30.
--, 2006b, Memorandum: update of the geotechnical report with respect to site
grading and the current grading plan, Robertson Ranch East, City of Carlsbad,
W.O. 3098-A2-SC, dated November 15.
GeoSoils,lne.
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__ , 2006c, Memorandum: discussion of earthwork recommendations in the vicinity
of a planned 84-inch storm drain, Cannon Road, Stations 127+20 to 1:36.+32,
Improvements for Robertson Ranch East, City of Carlsbad, California,
W.O. 3098-A2-SC, dated July 28.
__ , 2006d, Supplementto the update geotechnical evaluation regarding the distribution
of wick drains, Robertson Ranch East, Carlsbad, San Diego County, California,
w.O. 3098-A-SC, dated June.
__ " 2006e, Report of rough grading, Calavera Hills II, College Boulevard and Cannon
Road Thoroughfare, District No.4 (B&TD), Carlsbad Tract 00-02, Drawing 390-9A,
-Carlsbad, San Diego County, California, W.O. 3459-B2-SC, dated January 27.
__ ,2004, Updated geotechnical evaluation ofthe Robertson Ranch property, Carlsbad,
San Diego County, California, W.O. 3098-A2-SC, dated September 2.0.
--, 2002, Geotechnical evaluation of the Robertson Ranch property, City of Carlsbad,
San Diego County, California, W.O. 3098-A1-SC, dated January 29.
--, 2001 a, Preliminary findings of the geotechnical evaluation, Robertson Ranch
Property, City of Carlsbad, California, W.O. 3098-A-SC, dated July 31.
,2001 b, Preliminary geotechnical evaluation, Calavera Hills II, College Boulevard and
Cannon Road Thoroughfare, District No.4 (B&TD), City of Carlsbad, California,
W.O. 2863-A-SC, dated January 24.
Kanare, Howard, 2005, Concrete floors and moisture, Portland Cement Association,
Skokie, Illinois.
Nichols, Herbert L, Jr., 1976, Moving the Earth, The Workbook of Excavatjon, 3rd Edition,
McGraw-Hili Publishing Company.
O'Day Consultants, 2008, Grading plans for Robertson Ranch PA 22, Sheet 5, 40 scale,
job No. 01-1014, dated March.
Project Design Consultants, 2007, Alluvial shots to date, 5/09/2007, Robertson Ranch, Job
No. 3481.
Romanoff, M., 1957, Underground corrosion, National Bureau of Standards Circula,r 579,
Published by National Association of Corrosion Engineers, Houston, Texas,
reprinted 1989.
State of California, Department of Transportation, 2006, Highway design manual of
instructions, sixth edition; September printing.
Brookfield San Diego Builders, Inc.
File:e:\wp9\5300\5353b1.ror.pa22
GeoSoils, Ine.
Appehdix
Page 2
' ..... ~>
" ~.I./
W.O. 5353-E1-SC
TO: Brookfield San Diego Builders, Inc.
Attention: Mr. Adam Pevney, Mr. Greg McDonnell
FROM: Robert G. Crisman, CEG 1934, Andrew T. Guatelli, GE 2320
SUBJECT: Temporary Pavement Recommendations (f!re ProtectiQO,), Planning
Area 22 of Robertson Ranch ,East Village, City of Carlsbad, San Diego
County, California
Reference: "Report of Rough Grading, Planning Area 22 of Robertson Ranch,
East Village, Carlsbad, San Diego CountY, California," W.O. 5353-E1-SC,
dated March 6, 2009, by GeoSoils, Inc.'
In accordance with your request, GSI has reviewed the referenced report and site con<;litions with
respect to the construction of a temporary, all weather access road for fire service vehicles
(75,000 pounds total weight) during site construction. Based on our review and analysiS, the
following recommendations are provided.
Pavement Section
Based on our analysis, the following pavement options are provided:
1. Provide a minimum{g1n:ct!~s::qf compacted ~Itlc concret~3Dver prepared SUbgrade.r~~:;::---:'; '0
A thickened, turned down edge, with a minimum embedment of at least 4 inches (6 inches .
from top of pavement) should be provided along the edge of pavement to provide lateral
support.
2. Alternatively, provide a minimum 5 inches of compacted aggregate base over prepared
subgrade. An edge treatment is recommended to provide lateral support forthe pavement.
This edging may consist of either a: concrete "mOW" strip, or pressure.treated wood,
embedded at least 2 inches below the bottom of the base layer.
3. The edge treatments indicated in the alternatives indicated in 1 and 2 above may be
eliminated if sacrificial shoulders, with a minimum width of at least 3 feet, are provided.
.t--
"
5. -
,. 6.
"
7.
'j
DRAINAGE
, A. Concrete swales between parking lot aisles are dis90uraged~ Tipped sectionS
with concrete curb and gutters are, preferred. '
, B: Hydrology and hydraulic 'design shall be in accordance with Public Drainage
Standards. Pipe sizing, material specifications and pre-fabricated stn.ictures Shall
be designed by a Registered Civil Engineer and ,are subject to approvai' of the
City Engineer.
C. Concentrated site drainage may not surface flow across sidewalks onto public' ~r ,1
private streets. L~lj
D. 'Special design shall be required for all parking, lots Which, by design, may retain [ ';
storl}l waters to reduce down stream flooding. ' ---: i
E. Public storm drains may be included within the "general utility and access
easement" if specificaily approved by the City Engineer.
F. ,'Maximum fall across parking areas'shall be five percent (5%).
STRUCTURAL SECTION
A., Private streets shall be constructed with the same structural sections as public
streets. -
B. Parking lots and driveways shall be designed -based upon a traffic index of 4.5
and the "R" value of the soil(s) at the project site as determined by a Registered
Soils Engineer. Minimum section shall be 4"asphalt concrete. Modifications of
this Standard may be made if approved by ~he City Engineer.
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C~ 1--;
, ~-
-C. ' ' Oi:u.ck .. tQlJies~:'flJrQ.!JQJigai,kihgJQtS or aisles with an ADT gre~ter than 500 sbaICbe_] -,
C"d.e..Sjgnerl':'witb:..a fraffiOTrldeMT-g. All routes leading to trash enclosures shall '
be designed for h~avy loading, minimum 4" A.C: over 6" approved aggregate
base. The level loading area in front of trash enclosures'shall be concrete with a-
[
minimum thickness of 7-112 inches in conformance with GS-16. '
DEFINITIONS
, -
A. Driveway: Includes those portions of public and private property used to provide'
access from public right-of-way to private property and the areas on public and
private property used to queue or stack arriving and departing vehicles'-
Driveways' are the points of interface between the public/private cir.culation
systems. '
B. ," Traveled Way: Includes all public streets and all private streets or drives serving
more than 50 units or an average daily trip load of 500 or,more.
Page 6 of7
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PER MAP 15608
CT. 02-16
NOTPI
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£l£CTRONIC DATA FIlES ARE FOR REFERENCE
ONLY AND ARENDT TO BE USB) FOR
HORIZONTAL OR ~/mCA1 SUR~ CONTROL
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LEGEND
Artificial fill. placed under the purview of this
report
Artfficial fill -older. placed under the purview of
081 (2006e)
Quaternary alluvial deposns. circled where
buried
Quaternary terrace deposits. circled where
buried
Tertiary Santiago Formation, circled where
buried
Approximate location of remedial removal
bottom (leet MSL)
ApprOximate location of field density test
•.• -' ' ..... ·.Geologic Contact. dotted where buried. . .. ' .. ,. ...
N.A.P. Not A Part
. 0' 80' -----40'
SCAI.£: ," = 40'
------------ - -,~~~~;2);:i3~~:..:-
x47.J
DON RODOLFO DRIVE x 47.8
DESIGNED BY: K H
DRAWN BY: . c,[,
PROJECT MG/I.' G.O.
ENGINEER OF WORK:
GEORGE O'DAY
DATE: MARCH 2!!!!8
seAl E· AS SIfO\\H
JOB NO •• 00-100+
DATE:
ReE: 32014
"AS BUILT",
RCE. __ _
REVIEWED BY:
INSPECTOR
. DATE
DATE
.---
BENCHMARK:
alu liON: STANDARD M-10 STR£ETCEN7ERl.IN£
HElL MONUMENT
UlCA1IIIN: . CEN1ERJ.JN£ OF B.. CAIIINO R£AJ.
AT ENCIN££R'S STA TlON 454+92
PER R.S 1800-1
AEOORO FROM: CouNTY BENCH /£VEJ.S (NO. COIJNTY VERT.
CONTROl. DATA) .
EI.1VA1IDN: 88.479 DA TUM:· Us.c. til 6:s. NGVD 1929
_____ x 4.9.5
-----
HORIZONTAL CONTROL· w
..
. '
ALL LOCATIONS ARE APPROXIMATE
This document orefile is not a part of the Construction
Documents and should not be relied uponss being an .
accurate depiction of design.
RIVERSIDE CO ..
ORANGE CO.
SAN DIEGO CO.
ji AS-GRADED
GEOTECHNICAL MAP
PA22 1 of 1
5353-B-SC DATE 03/09 SCALE 1'=40' ..
~---+---1------------+-r-r---;t-4ISH5EET. '/ CITY OF CARLSBAD I SIiSEl.IS I
ENGINEERING· DEPARTMENT
GRAOING PLANS FOR:.
ROBERTSON RANCH PA 22 .
c.u.P. 07-04
~--I---I---------------'-+-"--t--t--ll---j I APPRO\IED: DAVID A HAUSER . . ~--I-----I----------------+--t--t---:l---j DEPUtY Ci1YENCHER PE 3308UXP. 8blJ/OS ~TE I
=-k==--I-LJ:L--------~----I"""DA_rlINiliArtliAiirtiNiiiiiL1 D BY: I--£!~~~f-!:!:::_:::=::::_I OIKD BY:
OTHER APPROVAL ClTYAPPROVAL RVWD BY: REVISION DESCRIPTION I . PRO.ECT NO. II DRA'MNG. NO.1 . C.UP. 07-04 .. .