HomeMy WebLinkAboutSDP 14-01; Burke Carlsbad Business Center; Site Development Plan (SDP) (3)13^ ) /^y
GEOCON
INCORPORATED
GEOTECHNICAL
ENVIRONMENTAL
MATERIALS
DUE DILIGENCE UPDATE
GEOTECHNICAL REPORT
CARLSBAD RACEWAY
BUSINESS PARK - LOT 17
CARLSBAD, CALIFORNIA
RECEIVED
JAN 0 6 2014
CITY OF CARLSBAD
PLANNING DIVISION
PREPARED FOR
AETHERCOMM, INC.
CARLSBAD, CALIFORNIA
OCTOBER 6, 2010
PROJECT 07349-42-11
GEOCON
INCOHPC HATED
GEOTECHNICAL • ENVIRONMENTAL • MATERIALS
Project No. 07349-42-11
October 6,2010
Aethercoinm, Inc.
3205 Lionshead Avenue
Carlsbad, Califomia 92010
Attention: Mr. Richard Martinez
Subject: CARLSBAD RACEWAY BUSINESS PARK - LOT 17
CARLSBAD, CALIFORNIA
DUE DILIGENCE UPDATE GEOTECHNICAL REPORT
Dear Mr. Martinez:
In accordance with your request, we have prepared this update geotechnical report to provide
recommendations pertinent to development of Lot 17 located within the Carlsbad Raceway Business
Park in Carlsbad, Califomia. Geocon provided testing and observation services during original
grading of the overall Carlsbad Raceway Business Park. Subsequent to the grading Opus West
purchased several lots within the development. It is unknown if additional grading occurred on Lot 17
subsequent to the original grading observed by Geocon Incorporated.
The site is underlain by compacted fill overlying the Santiago Formation. Based on our review of
available grading reports and the results of our recent field investigation and laboratory testing, it is
our opinion the soils underlying Lot 17 are suitable for support of additional fill and/or stmctural
loads and fbture development. The accompanying report describes the existing as-graded soil and
geologic conditions and provides grading recommendations and foundation design criteria for new
development.
Should you have questions regarding this update, or if we may be of further service, please contact
the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Trevor E. Myers
RCE 63773
) Rodney C. Mikesell
GE 2533
Garr^;' W. Can
CEG2201
RCE 56468
lion
TEM:RCM:dmc
(6/del) Addressee
6960 Flanders Df.ve • San Diego, California 921 ? 1-2974 • Telephone 858 558.6900 • Fax 858.558 6159
TABLE OF CONTENTS
1. PURPOSE AND SCOPE 1
2. SITE AND PROJECT DESCRIPTION 1
2.1 Proposed Site Development 2
3. SOIL AND GEOLOGIC CONDITIONS 2
3.1 Compacted Fill (Qcf) 3
3.2 Santiago Formation (Ts) 3
4. GROUNDWATER 3
5. GEOLOGIC HAZARDS 4
5.1 Faulting and Seismicity 4
5.2 Liquefaction 6
5.3 Ground Rupture 6
5.4 Landslides 7
5.5 Seiches and Tsunamis 7
6. CONCLUSIONS AND RECOMMENDATIONS 8
6.1 General 8
6.2 Grading 9
6.3 Seismic Design Criteria 11
6.4 Foundations 11
6.5 Concrete Slabs-on-Grade 12
6.6 Retaining Walls 14
6.7 Lateral Loading 15
6.8 Preliminary Pavement Recommendations 15
6.9 Detention Basin and Bioswale Recommendations 17
6.10 Site Drainage and Moisture Protection 18
6.11 Grading and Foundation Plan Review 18
LIMITATIONS AND UNIFORMITY OF CONDITIONS
MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
Figure 2, Geologic Map
Figure 3, Wall/Colum Footing Dimension Detail
Figure 4, Typical Retaining Wall Drain Detail
APPENDIX A
FIELD INVESTIGATION
Figures A-1 - A-6, Logs of Borings
APPENDIX B
LABORATORY TESTING
Table I, Summary of Laboratory Maximum Dry Density and Optimum Moisture Content Test Results
Table II, Summary of Laboratory Expansion Index Test Results
Table III, Summary of Laboratory pH and Resistivity Test Results
Table IV, Summary of Laboratory Sulfate Content Test Results
Figure B-1, Laboratory Consolidation Curves
APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
DUE DILIGENCE UPDATE GEOTECHNICAL REPORT
1. PURPOSE AND SCOPE
This report presents the results of an update geotechnical study for the proposed development of the
Carlsbad Raceway Business Park, Lot 17 of Tract C. T. 98-10. The site is located on Lionshead
Avenue, between Melrose Drive and Business Park Drive in Carlsbad, Califomia (see Vicinity Map,
Figure 1). The purpose of this due diligence update report is to assess the suitability of existing soils
for support of new improvements and to provide recommendations for continued development of the
lot. Our scope of work consisted of:
Reviewing previously submitted as-graded reports for the site and vicinity.
Drilling 6 exploratory borings at the site to observe and sample the subsurface geologic units.
Laboratory testing of representative soil sample collected during the subsurface investigation.
Providing an updated geologic map of the site.
Providing this report.
The scope of this study included a review of the following:
• Final Report of Testing and Obsermtion Service.^ During Site Grading [for] Carlsbad
Raceway Business Park, Lots I Through 28. Tract CT. 98-10, Carlsbad, California,
prepared by Geocon Incorporated, dated June 5, 2006 (Project No. 07349-42-02).
• Update Geotechnical Report, Opus Pointe at the Raceway, Lots 5 Through 11 (Inclusive) and
Lots 16 Through 25 (Inclusive), CT. 98-10, Carlsbad, California, prepared by Geocon
Incorporated, dated November 10, 2005 (Project No. 07349-42-06).
• Fault Hazard Evaluation, Carlsbad Raceway Business Park, CT. 98-10, Carlsbad,
California, prepared by Geocon Incorporated, dated March 1, 2005 (Project No. 07349-42-
02).
2. SITE AND PROJECT DESCRIPTION
2.1 Previous Site Development
The project site is located on Lionshead Avenue east of Melrose Drive, west of Business Park Drive,
and north of Palomar Airport Road in Carlsbad, Califomia. Lot 17 is part of the overall Carlsbad
Raceway Business Park that was graded as a continuous operation between August 2004 and May
2006. Compaction test results and professional opinions pertaining to the original mass grading are
summarized in Geocon's above-referenced 2006 report. Original grading for Lot 17 resulted in a
sheet-graded lot with fill thickness ranging between 21 to 54 feet.
Project No. 07349-42-11 - 1 - October 6, 2010
During original grading, unsuitable material was removed to expose the underlying Santiago
formation. A canyon subdrain was installed along the axis of the westerly draining canyon. As
indicated by test results and observations, fill soils placed during grading were compacted to at least
90 percent relative compaction at the locations tested.
Several lots, including Lot 17, were sold to Opus West subsequent to mass grading. Geocon
Incorporated prepared an update geotechnical report for Opus West (see referenced 2005 report).
Geocon Incorporated was not retained to provide follow-up geotechnical services for continued
development of the lots. Additional grading, if any, that occurred on Lot 17 was not observed and
tested by Geocon Incorporated. Lot 17 was utilized as a stockpile area for excess spoils during
regrading of the lots purchased by Opus West.
The existing property is covered with dirt and minor amount of weed growth. Recently, the soil
stockpile was exported from the site. A desilting basin is present in the northwest comer of the site.
Utility easements exist along the west and north sides of the site. A building has been constructed on
the adjacent lot to the west (Lot 18). Lot 16 to the east is vacant.
2.1 Proposed Site Development
Site plans were not available for our review at the time this report was prepared. However, we
understand the project may consist of a commercial and/or light industrial stmcture with associated
paved parking lots and drive areas, similar to existing buildings in the area. The stmcture will likely be
one or two story concrete tilt up constmction with roll up metal doors for vehicle access. We expect
minor cuts and fills on the order of 3 feet or less from current sheet grade elevations to constmct a level
building pad.
The locations and descriptions of the site and proposed development are based on our field
observations and our understanding of project development. If project details vary significantly from
those described above, Geocon Incorporated should be contacted to determine the necessity for
review and revision of this report.
3. SOIL AND GEOLOGIC CONDITIONS
In general, the near surface fill soils are composed of silty to clayey fill soils exhibiting a "low" to
"medium" (expansion index less than 90) expansion potential. Additionally, soluble sulfate testing on
near surface soil samples indicates a "severe" condition.
Lot 17 is underlain by compacted fill that could range from approximately 20 feet to 55 feet in depth.
Bedrock underlying Lot 17 is comprised of Eocene-age Santiago Fonnation. Compacted fills are
composed of soil generated from excavations in alluvium (canyon cleanouts), and excavation of
Project No. 07349-42-11 - 2 - October 6, 2010
fonnational soils. The distribution of the geologic units and mapped geologic contacts for the as-
graded conditions are depicted in the referenced as-graded geotechnical report and Figure 2 of this
report. Sheet grade elevations shown on Figure 2 were taken from sheet grade elevations shown on
the original grading plans. We do not know if these elevations match existing sheet grade elevations.
Fill placed and compacted under the observation of Geocon Incorporated and summarized in
Geocon's referenced November 2005 update report and 2006 as-graded report were to the sheet grade
elevations shown on Figure 2. Site elevations higher than those shown on Figure 2 indicate fills
placed after the completion of original grading.
Compacted fill and geologic units encountered in our field investigation are described below.
3.1 Compacted Fill (Qcf)
Compacted fill placed during grading for the Carlsbad Raceway project exists across Lot 17. Grading
for the project was completed in May 2006. Observation and compaction testing services during mass
grading were provided by Geocon Incorporated. Mass grading for the site resulted in fills with a
maximum thickness of approximately 54 feet. The fill consists predominantly of silty and clayey soil.
The fill is considered suitable for support of stmctural improvements.
Additional fills subsequent to mass grading may have occurred on Lot 17. The lot was used to
stockpile spoils during development of other Lots purchased by Opus West. Geocon Incorporated is
not the engineer of record for lots purchased by Opus West, and was not provided with a geotechnical
report documenting the placement of compacted fills subsequent to original mass grading. However,
based on our recent exploratory borings, the fill on Lot 17 appears to be suitable for support of
continued development of the property.
3.2 Santiago Formation (Ts)
Dense siltstone and claystone interbedded with fine sand ofthe Santiago Formation are present below
the fill soils. Clayey soils generated from this formation generally have a "high" Expansion Index;
however, sandy beds possess a 'Very low" expansion potential. Portions of the Santiago Formation
(deep cut areas) were found to generally possess a severe potential for soluble sulfate exposure.
4. GROUNDWATER
Groundwater was encountered at the bottom of alluvium removals in the westerly drainage where a
subdrain was placed. The existing geologic units are susceptible to seepage if irrigated or subjected to
poor drainage practices, therefore, seepage may appear in areas which previously were dry.
Project No. 07349-42-11 - 3 - October 6, 2010
5. GEOLOGIC HAZARDS
5.1 Faulting and Seismicity
A review of the referenced geologic reports and our knowledge of the general area indicate that the
site is not underlain by an active fault. An active fault is defined by the California Geological Survey
(CGS) as a fault showing evidence for activity within the last 11,000 years. The site is not located
within State of Califomia Earthquake Fault Zone.
A fault was exposed during previous grading on a cut slope descending from Palomar Airport Road
that trended in a northwest-southeast direction toward the project site. Fault trenches were excavated
along the projection of the fault to more accurately delineate the fauh. Faults were also exposed
during grading on the north facing slopes and on Lots 9 and 11 and extended into Lots 16 and 17.
These faults were mapped to trend northerly through the site. Fault traces were located by land survey
methods. The Santiago Formation bedrock between the two faults was fractured, and was removed
and replaced by a stability fill bounding the south margins of Lots 9 and 11.
Older alluvial soils overlying the Santiago Formation were not offset in the fault trenches.
Radiocarbon dating and infonnation obtained from fault trenching (see Geocon March 2005) indicate
the faults are potentially active or older. The California Geologic Survey does not require building
setbacks for potentially active faults. This fault is not considered adverse with respect to proposed site
development.
According to the computer program EZ-FRISK (Version 7.43), 12 known active faults are located
within a search radius of 50 miles from the property. The nearest known active fault is the Rose
Canyon Fault, located approximately 9 miles west of the site and is the dominant source of potential
ground motion. Earthquakes that might occur on the Rose Canyon Fault Zone or other faults within
the southem California and northem Baja Califomia area are potential generators of significant
ground motion at the site. The estimated deterministic maximum earthquake magnitude and peak
ground acceleration for the Rose Canyon Fault are 7.2 and 0.27g, respectively. Table 5.1.1 lists the
estimated maximum earthquake magnitude and peak ground acceleration for the most dominant faults
in relationship to the site location. We calculated peak ground acceleration (PGA) using Boore-
Atkinson (2008) NGA USGS2008, Campbell-Bozorgnia (2008) NGA USGS, and Chiou-Youngs
(2008) NGA acceleration-attenuation relationships.
Project No. 07349-42-11 - 4 - October 6, 2010
TABLE 5.1.1
DETERMINISTIC SPECTRA SITE PARAMETERS
Fault Name
Distance
from Site
(miles)
Maximum
Earthquake
Magnitude
(Mw)
Peak Ground Acceleration
Fault Name
Distance
from Site
(miles)
Maximum
Earthquake
Magnitude
(Mw)
Boore-
Atkinson
2008 (g)
Campbell-
Bozorgnia
2008 (g)
Chiou-
Youngs
2008 (g)
Rose Canyon 9 7.2 0.26 0.22 0.27
Newport-Inglewood (offshore) 1 1 7.1 0.23 0.19 0.22
Elsinore (Julian) 21 7.1 0.17 0.12 0.13
Elsinore (Temecula) 21 7.1 0.15 0.11 0.10
Coronado Bank 24 7.6 0.18 0.12 0.15
Elsinore (Glen-Ivy) 36 6.8 0.10 0.07 0.06
Earthquake Valley 38 6.5 0.08 0.06 0.04
San Joaquin Hills Thrust 41 6.6 0.08 0.07 0.05
Pales Verdes 42 7.3 O.ll 0.07 0.08
San Jacinto (Anza) 44 7.2 0.10 0.07 0.07
San Jacinto (San Jacinto Valley) 46 6.9 0.09 0.06 0.05
We used the computer program EZ-FRISK to perform a probabilistic seismic hazard analysis. The
computer program EZ-FRISK operates under the assumption that the occurrence rate of earthquakes
on each mapped Quaternary fault is proportional to the fault's slip rate. The program accounts for
earthquake magnitude as a function of fault rupture length, and site acceleration estimates are made
using the earthquake magnitude and distance from the site to the rupture zone. The program also
accounts for uncertainty in each of following: (1) earthquake magnitude, (2) mpture length for a
given magnitude, (3) location of the rupmre zone, (4) maximum possible magnitude of a given
earthquake, and (5) acceleration at the site from a given earthquake along each fault. By calculating
the expected accelerations from considered earthquake sources, the program calculates the total
average annual expected number of occurrences of site acceleration greater than a specified value.
We utilized acceleration-attenuation relationships suggested by Boore-Atkinson (2008) NGA USGS,
Campbell-Bozorgnia (2008) NGA USGS, and Chiou-Youngs (2008) in the analysis. Table 5.1.2
presents the site-specific probabilistic seismic hazard parameters including acceleration-attenuation
relationships and the probability of exceedence.
Project No. 07349-42-1 -5-October 6, 2010
TABLE 5.1.2
PROBABILISTIC SEISMIC HAZARD PARAMETERS
Probability of Exceedence
Peak Ground Acceleration
Probability of Exceedence Boore-Atkinson,
2007 (g)
Campbell-Bozorgnia,
2008 (g)
Chiou-Youngs,
2008 (g)
2% in a 50 Year Period 0.55 0.44 0.52
5% in a 50 Year Period 0.44 0.35 0.40
10% in a 50 Year Period 0.35 0.2S
The California Geologic Survey (CGS) has a program that calculates the ground motion for a
10 percent of probability of exceedence in 50 years based on an average of several attenuation
relationships. Table 5.1.3 presents the calculated results from the Probabilistic Seismic Hazards
Mapping Ground Motion Page from the CGS website.
TABLE 5.1.3
PROBABILISTIC SITE PARAMETERS FOR SELECTED FAULTS
CALIFORNIA GEOLOGIC SURVEY
Calculated Acceleration (g)
Firm Rock
Calculated Acceleration (g)
Soft Rock
Calculated Acceleration (g)
Alluvium
0.25 0.27 0.31
While listing peak accelerations is useful for comparison of potential effects of fault activity in a
region, other considerations are important in seismic design, including the frequency and duration of
motion and the soil conditions underlying the site. Seismic design of the stmctures should be
evaluated in accordance with the Califomia Building Code (CBC) guidelines currently adopted by the
City of Carlsbad.
5.2 Liquefaction
Liquefaction typically occurs in cohesionless sands below the water table as a result of rapid pore
water pressure increase from earthquake-generated ground accelerations. The risk liquefaction hazard
occurring within the site soils is considered to be 'Very low" due to the lack of a near surface
permanent groundwater condition and the dense nature of the fonnational and compacted fill soils.
5.3 Ground Rupture
The risk associated with ground rupture hazard is very low due to the absence of active faults at the
subject site.
Project No. 07349-42-11 -6-October6, 2010
5.4 Landslides
No evidence of landslides or slope instability were observed on the Lot during previous grading or
observed during our recent field investigation. It is our opinion that the risk associated with landslide
hazard at the site is low.
5.5 Seiches and Tsunamis
The site is located over 5 miles from the coast at an elevation near 400 feet above mean sea level
(MSL). Wave heights and mn-up elevations from tsunami along the San Diego Coast have
historically fallen within the normal range ofthe tides. The County of San Diego Hazard Mitigation
Plan maps zones of high risk for tsunami mn-up for coastal areas diroughout the county. The site is
not included in the high-risk hazard area. The site is not located near or downstream of any large
body of water. The risk associated with tsunami or seiche hazard is low.
Project No. 07349-42-11 - 7 - October 6, 2010
6. CONCLUSIONS AND RECOMMENDATIONS
6.1 General
6.1.1 No soil or geologic conditions were encountered diat, in our opinion, would preclude the
continued development of the property as presently planned, provided that the
recommendations of this report are followed.
6.1.2 In-place density tests performed during previous mass grading indicate fills were
compacted to at least 90 percent relative compaction at the locations tested. The fills are
stmcmral and considered suitable for support of additional fill and/or stmctural loading.
6.1.3 Based on field and laboratory studies perfonned for this report, the soils at the site appear
to be suitable for support of future development.
6.1.4 The soil encountered in the field investigation has a "medium" expansion potential
(expansion index [El] of 90 or less) as defined by 2007 Califomia Building Code (CBC)
Section 1802.3.2. Table 6.1.1 presents soil classifications based on the expansion index.
The expansion index test results are presented in Appendix B.
TABLE 6.1.1
SOIL CLASSIFICATION BASED ON EXPANSION INDEX
Expansion Index (EI) Soil Classification
0-20 Very Low
21-50 Low
51-90 Medium
91 - 130 High
Greater Than 130 Very High
6.1.5 Water-soluble sulfate testing was conducted on samples of the on-site near surface soils to
check whether the soils contain high enough sulfate concentrations that could damage
normal portland cement concrete. The laboratory test results are summarized in
Appendix A. The test results indicate a "severe" sulfate rating based on Table 19-A-4 of
the California Building Code (CBC). CBC guidelines should be followed in determining
the type of concrete to be used. Table 6.1.2 presents a summary of concrete requirements
set forth by CBC Table 19A-A-4. The presence of water-soluble sulfate is not a visually
discernible characteristic; therefore, other soil samples from die site could yield different
concentrations. Additionally, over time, landscaping activities (i.e., addition of fertilizers
and other soil nutrients) may affect the concentration. Representative samples of the finish
grade soils should be conducted at the completion of fine grading and additional sulfate
Project No. 07349-42-11 October 6, 2010
testing should be perfonned on acmal samples of the materials that will be in contact with
concrete.
TABLE 6.1.2
REQUIREMENTS FOR CONCRETE EXPOSED TO SULFATE-CONTAINING
SOLUTIONS (FROM CBC TABLE 19-A-4)
Sulfate
Exposure
Water-Soluble
Sulfate Percent
by Weight
Cement
Type
Maximum Water
to Cement Ratio
by Weight
Minimum
Compressive
Strength (psi)
Negligible 0.00-0.10 ~ — —
Moderate 0.10-0.20 11, IP(MS, IS(MS) 0.50 4.000
Severe 0.20-2.00 V 045 4,500
Very Severe over 2.00 V plus pozzolan 0.45 4,500
6.1.6 Potential-of-hydrogen (pH) and resistivity tests of the near surface soils indicate a pH
varying from 8.1 to 8.2 with resistivity varying from 510 to 560 ohm centimeters. The
laboratory test results are provided in Appendix A. The low resistivity indicates a corrosive
environment that impact buried metal. Geocon Incorporated does not practice in the field of
corrosion engineering. Therefore, if improvements that could be susceptible to corrosion
are planned, it is recommended that a corrosion specialist be consulted to provide site-
specific recommendations.
6.1.7 Additional sampling and testing for expansion index and soluble sulfate content of finish
grade soils at building locations should be performed at the completion of fine grading.
6.1.8 Excavation of fill soils should generally be possible with moderate effort using
conventional, heavy-duty equipment during grading and trenching operations. Excavations
of formational material, if any, will require heavy effort and may generate oversize rock
that could require special handling and disposal.
6.2 Grading
6.2.1 All grading should be performed in accordance with the Recommended Grading
Specifications in Appendix C. Where the recommendations of this section conflict with
those in Appendix C, the recommendations of this section take precedence. All
earthwork should be observed and all fills tested for proper compaction by Geocon
Incorporated.
Project No. 07349-42-11 -9-October 6,2010
6.2.2 Prior to commencing grading, a preconstmction conference should be held at the site with
the owner or developer, grading contractor, civil engineer, and geotechnical engineer in
attendance. Special soil handling and/or the grading plans can be discussed at that time.
6.2.3 Site preparation should begin with the removal of all deleterious material and vegetation.
The depth of removal should be such that material exposed in cut areas or soil to be used as
fill is relatively free of organic matter. Material generated during stripping and/or site
demolition should be exported from the site.
6.2.4 To prepare the lot for support of stmcmral improvements, we recommend the upper 1-foot
of existing soil be removed, moisture conditioned, and recompacted. Prior to placing fill,
the upper 1-foot below the removal should be scarified, moisture conditioned to near
optimum moisture content, and recompacted. Fill soils may then be placed and compacted
to design finish grade elevations. Where cuts in excess of 1 foot are made to achieve pad
grade, in-place density tests should be performed at the cut elevation to check the moisture
content of soils that will be at building pad grade. Additional removal and recompaction
may be required if loose, dry, or otherwise unsuitable soil is encountered at the base of
removals.
6.2.5 In the existing desilting basin, all loose/soft soft soil should be removed to expose
competent compacted fill. We expect removal deptlis on the order of 2 to 3 feet will be
required. The resuhing excavation should be backfilled with compacted fill.
6.2.6 If highly expansive soils are exposed at finish grade, the building pad should be
overexcavated at least 3 feet and replaced with "low" to "medium" expansive soil to
mitigate adverse conditions from expansive soil movement.
6.2.7 Expansive soils should be placed outside of building pads, preferably in landscape areas, to
reduce the potential for distress to buildings and surface improvements.
6.2.8 All fill, including scarified ground surfaces, should be compacted to at least 90 percent of
laboratory maximum dry density in accordance with ASTM Test Procedure D 1557-02, at
or slightly above optimum moismre content. Fill materials with in-place density test results
indicating moisture contents less than optimum will require additional moisture
conditioning before placing additional fill.
6.2.9 Imported soil, if required, should consist of granular material with a "low" expansion
potential and negligible sulfate rating. Once borrow sites have been identified, soil samples
Project No. 07349-42-11 - 10 - October 6, 2010
should be collected and subjected to laboratory testing to verify conformance with the
expansion and soluble sulfate criteria.
6.3 Seismic Design Criteria
6.3.1 We used the computer program Seismic Hazard Curves and Uniform Hazard Response
Spectra, provided by the USGS. Table 6.3 summarizes site-specific design criteria obtained
from the 2007 Califomia Building Code (CBC; Based on the 2006 International Building
Code [IBC]), Chapter 16 Stmctural Design, Section 1613 Earthquake Loads. The short
spectral response uses a period of 0.2 second.
TABLE 6.3
2007 CBC SEISMIC DESIGN PARAMETERS
Parameter Value IBC-06 Reference
Site ( la.ss C Table 1613.5.2
Spectral Response - Class B (short), Ss 1.079g Figure 1613.5(3)
Spectral Response - Class B (1 sec), S] 0.409g Figure 1613.5(4)
Site Coefficient, FA 1.00 Table 1613.5.3(1)
Site Coefficient, Fv 1.591 Table 1613.5.3(2)
Maximum Considered Earthquake
Spectral Response Acceleration (short), SMS 1.153g Section 1613.5.3 (Eqn 16-37)
Maximum Considered Earthquake
Spectral Response Acceleration - (1 sec), SMI 0.65 Ig Section 1613.5.3 (Eqn 16-38)
5% Damped Design
Spectral Response Acceleration (short), SDS 0.769g Section 1613.5.4 (Eqn 16-39)
5% Damped Design
Spectral Response Acceleration (1 sec), Spi 0.434g Section 1613.5.4 (Eqn 16-40)
6.3.2 Conformance to the criteria in Table 6.3 for seismic design does not constitute any kind of
guarantee or assurance that significant stmctural damage or ground failure will not occur if
a large earthquake occurs. The primary goal of seismic design is to protect life, not to avoid
all damage, since such design may be economically prohibitive.
6.4 Foundations
6.4.1 The proposed stmcture can be supported on a shallow foundation system foimded in
compacted fill. Foundations for the stmcmre should consist of continuous strip footings
and/or isolated spread footings. Continuous footings should be at least 12 inches wide and
extend at least 24 inches below lowest adjacent pad grade. Isolated spread footings should
have a tninimum width of 2 feet and should also extend at least 24 inches below lowest
Project No. 07349-42-1 - 11 -October 6, 2010
adjacent pad grade. Concrete reinforcement for continuous footings should consist of at
least four. No. 5 steel bars placed horizontally in the footings, two near the top and two
near die bottom. The project stmcmral engineer should design the concrete reinforcement
for the spread footings. A footing dimension detail is presented in Figure 2.
6.4.2 The minimum reinforcement recommended herein is based on soil characteristics only (Fl
of 90 or less) and is not intended to replace reinforcement required for stmctural
considerations.
6.4.3 The recommended allowable bearing capacity for foundations with minimum dimensions
described herein is 2,000 pounds per square foot (psf)- llie allowable soil bearing pressure
may be increased by an additional 300 psf and 500 psf for each additional foot of
foundation width and depth, respectively, to a maximum allowable bearing capacity of
4,000 psf. The values presented herein are for dead plus live loads and may be increased by
one-third when considering transient loads due to wind or seismic forces.
6.4.4 Settlement due to footing loads conforming to the above recommended allowable soil
bearing pressures are expected to be less than 1-inch total and ^/4-inch differential over a
span of 40 feet.
6.4.5 Footings should not be located within 7 feet of the tops of slopes. Footings that must be
located within this zone should be extended in depth such that the outer bottom edge of the
footing is at least 7 feet horizontally from the face of the finished slope.
6.4.6 No special subgrade presaturation is deemed necessary prior to placement of concTcte.
However, the slab and foundation subgrade should be sprinkled as necessary to maintain a
moist condition as would be expected in any concrete placement.
6.4.7 Foundation excavations should be observed by a representative of Geocon Incorporated
prior to the placement of reinforcing steel and concrete to check that the exposed soil
conditions are consistent with those anticipated and have been extended to appropriate
bearing strata. If unexpected soil conditions are encountered, foundation modifications may
be required.
6.5 Concrete Slabs-on-Grade
6.5.1 Interior concrete slabs-on-grade should be at least 5 inches thick. Point loads or line loads
from forklifts, other equipment or stmctures should be considered during stmctural design
of the slabs-on-grade. Minimum slab reinforcement should consist of No. 3 steel
Project No. 07349-42- II - 12 - October 6, 2010
reinforcing bars placed 18 inches on center in both horizontal directions and positioned
near the slab midpoint.
6.5.2 Concrete slabs on grade should be imderlain by 4 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 retarder placed in the middle of the sand layer. The project architect
should specify the type of vapor retarder used based on the type of floor covering that will be
installed. The vapor retarder design should be consistent with the guidelines presented in
Section 9.3 of the American Concrete Institute's (ACI) Guide for Concrete Slabs that
Receive Moisture-Sensitive Flooring Materials (ACI 302.2R-06).
6.5.3 All exterior concrete flatwork not subject to vehicular traffic should be constmcted in
accordance with the following recommendations. Slab panels in excess of eight feet square
should be reinforced with No. 3 steel bars spaced 24 inches center to center and positioned
near the middle of the slab. All concrete flatwork should be provided with crack control
joints to reduce and/or control shrinkage cracking. The project stmctural engineer should
determine crack control spacing based on the slab thickness and intended usage. Criteria of
the American Concrete Institute (ACI) should be taken into consideration when
establishing crack control spacing. Subgrade soils for exterior slabs not subjected to vehicle
loads should be compacted to at least 90 percent of the maximum dry density at near-
optimum moisture content.
6.5.4 Where exterior flatworic abuts the stmcmre at entrance or exit areas, the exterior slab
should be dowelled into the foundation stemwall. This recommendation is intended to
reduce the potential for differential elevations that could resuh from differential settlement
or minor heave of the flatwoilc. Consideration should also be given to doweling sidewalks
to curbs to reduce potential off-set as a result of heave or settlement. The project stmctural
engineer should provide dowelling details.
6.5.5 The above slab-on-grade dimensions and minimum reinforcement recommendations are
based upon soil conditions only and are not intended to be used in lieu of those required for
stmctural purposes.
6.5.6 The recommendations of this report are intended to reduce the potential for cracking of
slabs due to differential settlement of fills of varying thickness and expansive soils.
However, even widi the incorporation of the recommendations presented herein,
foundations, stucco walls, and slabs-on-grade placed on such soil conditions may exhibit
some cracking due to soil movement and/or shrinkage. The occurrence of concrete
Project No. 07349-42-11 - 13 - October 6, 2010
shrinkage cracks is independent of the supporting soil characteristics. Their occurrence
may be reduced and/or controlled by: (1) limiting the slump ofthe concrete, (2) proper
concrete placement and curing, and (3) by the placement of crack-control joints at periodic
intervals, particularly where re-entrant slab corners occur.
6.5.7 Geocon Incorporated should be consulted to provide additional design parameters as
required by the strucmral engineer.
6.6 Retaining Walls
6.6.1 Retaining walls that are allowed to rotate more than 0.001 H (where H equals the height of
the retaining portion of the wall) at the top of the wall, 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 2:1
(horizontakvertical), an active soil pressure of 50 pcf is recommoided. Soil with an
expansion index (EI) of greater than 50 should not be used as backfill material behind
retaining walls.
6.6.2 Where walls are resfrained 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.
6.6.3 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 recommendations herein assume a properly
compacted granular (EI of 50 or less) free-draining backfill material 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.
6.6.4 The stmctural engineer should detennine die seismic design category for the project and if
retaining walls need to incorporate seismic lateral loads. A seismic load of 18H should be
used for design. The seismic load is dependent on the retained height where H is the height
of the wall, in feet, and the calculated loads result in pounds per square foot (psf) exerted at
the top of the wall and zero at the base of the wall. We used a peak site acceleration of
0.3Ig calculated using SDS/2.5 USGS and applying a pseudo-static coefficient of 0.5.
Project No. 07349-42-11 - 14 - October 6, 2010
6.6.5 In general, shallow conventional wall footings founded in properly compacted fill or
fonnational materials and having a minimum depth and width of one foot may be designed
for an allowable soil bearing pressure of 2,000 psf, provided the soil within 5 feet below
the base of the wall has been properly compacted during remedial grading and possess 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 consuUed where such a condition is anticipated.
6.7 Lateral Loading
6.7.1 To resist lateral loads, a passive pressure exerted by an equivalent fluid density of
300 pounds per cubic foot (pcf) should be used for the design of footings or shear keys.
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 in areas not protected by floor slabs or pavement should not be included
in design for passive resistance.
6.7.2 If friction is to be used to resist lateral loads, an allowable coefficient of friction between
soil and concrete of 0.4 should be used for design.
6.8 Preliminary Pavement Recommendations
6.8.1 The following recommendations are provided for preliminary design purposes. Final
pavement section design will depend upon soil conditions exposed at subgrade elevation
and results of Resistance Value (R-Value) tests perfonned on samples of actual subgrade
soils. The preliminary pavement section recommendations are based on an R-value of 12
(average value obtained from 13 subgrade soil samples collected in Lionshead Drive, Eagle
Drive, and Melrose Drive). Asphalt concrete sections are based on the City of Carlsbad
Structural Sections of Streets and Alley, Supplemental Standard GS-17 and the Caltrans
Highway Design Manual. We calculated the rigid pavement section in general
confonnance with the procedure recommended by the American Concrete Institute report
ACI 330R-08 Guide for Design and Construction of Concrete Parking Lots.
Project No. 07349-42-11 - 15 - October 6, 2010
TABLE 6.8
PRELIMINARY PAVEMENT DESIGN SECTIONS
Location
Assumed
Traffic
Index (TI)
Asphah Concrete Portland Cement Concrete
Location
Assumed
Traffic
Index (TI)
Asphalt
Concrete
(inches)
Class 2
Base
(inches)
Concrete
(inches)
Class 2
Base
(inches)
Automobile Parking 4.5 4 4 5 0
Automobile Driveways 5 4 6.5 5.5 4
Heavy Truck Area 6 4 12.5 6
6.8.2 Samples of pavement subgrade should be collected prior to placement of base and asphalt
for laboratory testing to aid in evaluation of the preliminary flexible pavement sections.
Additional pavement recommendations may be forthcoming depending upon laboratory
tests of the exposed subgrade.
6.8.3 Asphalt concrete should conform to Section 203-6 of the Standard Specifications for
Public Works Construction (Green Book). Class 2 aggregate base materials should conform
to Section 26-1.02A ofthe Standard Specifications ofthe State of Califomia, Department
of Transportation (Caltrans).
6.8.4 Prior to placing base material, the upper 12 inches of subgrade should be scarified,
moisture conditioned and compacted to a minimum of 95 percent of the maximum dry
density as determined by ASTM D 1557-02. The base material should be compacted to at
least 95 percent relative compaction. Asphalt concrete should be compacted to a minimum
of 95 percent of the laboratory Hveem density.
6.8.5 The performance of pavements is highly dependent upon providing positive surface
drainage away from the edge of pavements. Ponding of water on or adjacent to pavements
will likely result in samration of the subgrade materials and subsequent pavement distress.
If planter islands are planned, the perimeter curb should extend at least 6 inches below the
bottom of the Class 2 aggregate base.
6.8.6 Loading aprons such as trash bin enclosures and loading docks should utilize portland
cement concrete as recommended above for tmck traffic areas. The pavement should be at
least 6 inches thick and reinforced widi No. 3 steel reinforcing bars spaced 18 inches on
center in both directions placed at the slab midpoint. The concrete should extend out from
the loading dock or trash bin such that botii the front and rear wheels of the truck will be
located on reinforced concrete pavement when loading.
Project No. 07349-42-11 - 16-October 6, 2010
6.8.7 The following recommendations are being provided for portland cement concrete pavement
areas. The project stmctural engineer should provide reinforcement for the concrete slabs.
• The Portland cement concrete pavement sections in Table 6.8 are based on a
minimum concrete flexural strength (modulus of mpture, MR) of 500 pounds per
square inch (psi) (compressive strength of 3,200 psi), a modulus of subgrade
reaction, k, of 100 pounds per cubic inch (pci), fraffic category "A" for
automobiles and traffic category "B" for heavy tmck traffic assuming an average
daily tmck traffic of 25 or less. Geocon Incorporated should be contacted for
possible revisions to the pavement design sections if these design parameters are
not conect.
• A thickened edge or integral curb should be constructed on the outside of concrete
slabs subjected to wheel loads. The thickened edge should be 1.2 times the slab
thickness at the slab edge and taper to the recommended slab thickness 3 feet
behind the face of the slab (e.g., an 8-inch-thick slab would have a 9.6-inch-thick
edge).
• To control the location and spread of concrete shrinkage cracks, it is recommended
that crack control joints be included in the design of the concrete pavement slab.
Crack control joint spacing should not exceed, in feet, twice the recommended slab
thickness in inches (e.g., 16 by 16 feet for an 8-inch-thick slab). The crack-control
joints should be created while the concrete is still fresh using a grooving tool, or
shortly thereafter using saw cuts. The joint should extend into the slab a minimum
of one-fourth of the slab thickness.
• Construction joints should be provided at the interface between areas of concrete
placed at different times during constmction. Doweling is recommended between
the joints to transfer anticipated tmck traffic loading. Dowels should be located at
the midpoint ofthe slab and be spaced at 12 inches on center. As an alternative to
doweling, a keyway may be used to transfer wheel loads. The keyway should have
a width of 0.2 times the slab thickness and a depth equal to 0.1 times the slab
thickness (e.g., for a 7-inch-thick slab, the keyway would have a width of
approximately 1.4 inches and a depth of 0.7 inches). The project stmctural
engineer should provide alternative recommendations for load transfer.
• Consideration should be given to the use of a crack-control joint and expansion
joint filler or sealer to aid in preventing migration of water into subgrade and base
materials. Appropriate fillers or sealers are discussed in section 7.3 of the
referenced ACI guide.
6.9 Detention Basin and Bioswale Recommendations
6.9.1 Any detention basins, bioswales and bio-remediation areas should be designed by the
project civil engineer and reviewed by Geocon Incorporated. Typically, bioswales consist
of a surface layer of vegetation underlain by clean sand. A subdrain should be provided
beneath the sand layer. Prior to discharging into the storm drain pipe, a seepage cutoff wall
should be constructed at the interface between the subdrain and storm drain pipe. The
Project No. 07349-42-11 - 17 - October 6, 2010
concrete cut-off wall should extend at least 6-inches beyond the perimeter of the gravel-
packed subdrain system.
6.9.2 Distress may be caused to plaimed improvements and properties located hydrologically
downstream or adjacent to these devices. The distress depends on the amoimt of water to be
detained, its residence time, soil penneability, and other factors. We have not performed a
hydrogeology study at the site. Downstream and adjacent properties may be subjected to
seeps, springs, slope instability, raised groundwater, movement of foundations and slabs, or
other impacts as a result of water infilfration. Due to site soil and geologic conditions,
bioswales and bio-remediation areas should be lined with an impenneable barrier, such as a
thick visqueen, to prevent water infiltration in to the underlying compacted fill.
6.9.3 The landscape architect should be consulted to provide the appropriate plant
recommendations. If drought resistant plants are not used, irrigation may be required.
6.10 Site Drainage and Moisture Protection
6.10.1 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 stmcmres in accordance with 2007 CBC 1803.3 or other applicable
standards. In 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 cany mnoff away from the proposed stmcture.
6.10.2 In the case of basement walls or building walls retaining landscaping areas, a water-
proofing system should be used on the wall and joints, and a Miradrain drainage panel (or
similar) should be placed over the waterproofing. The project architect or civil engineer
should provide detailed specifications on the plans for all waterproofing and drainage.
6.10.3 Underground utilities should be leak free. Utility and irrigation lines should be checked
periodically for leaks, and detected leaks should be repaired promptly. Detrimental soil
movement could occur if water is allowed to infiltrate the soil for prolonged periods of
time.
6.11 Grading and Foundation Plan Review
6.11.1 Geocon Incorporated should review the grading plans and foundation plans for die project
prior to final design submittal to evaluate whether additional analyses and/or
recommendations are required.
Project No. 07349-42-11 - 18 - October 6, 2010
LIMrrATIONS AND UNIFORMITY OF CONDITIONS
1. The 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 constmction,
or if die proposed constmction will differ from that anticipated herein, Geocon Incorporated
should be notified so that supplemental recommendations can be given. The evaluation or
identification ofthe potential presence of hazardous or conosive 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 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 that 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 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 perfonned the geotechnical investigation for the project should be retained to
provide testing and observation services during constmction to provide continuity of
geotechnical interpretation and to check that the recommendations presented for geotechnical
aspects of site development are incorporated during site grading, constmction of
improvements, and excavation of foundations. If another geotechnical firm is selected to
perform the testing and observation services during constmction operations, that firm should
prepare a letter indicating their intent to assume the responsibilities of project geotechnical
engineer of record. A copy ofthe letter should be provided to the regulatory agency for their
records. In addition, that firm should provide revised recommendations conceming the
geotechnical aspects of the proposed development, or a written acknowledgement of their
concunence 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. 07349-42-11 October 6, 2010
THE GEOGRAPHICAL INFORMATION MADE AVAILABLE FOR DISPLAY WAS PROVIDED BY GOOGLE EARTH.
SUBJECT TO A LICENSING AGREEMENT. THE INFORMATION IS FOR ILLUSTRATIVE PURPOSES ONLY; IT IS
NOT INTENDED FOR CLIENT'S USE OR RELIANCE AND SHALL NOT BE REPRODUCED BY CLIENT. CLIENT
SHALL INDEMNIFY, DEFEND AND HOLD HARMLESS GEOCON FROM ANY LIABILITY INCURRED AS A RESULT
OF SUCH USE OR RELIANCE BY CLIENT.
NO SCALE
GEOCON
INCORPORATED
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
TR/AML DSK/GTYPD
VICINITY MAP
CARLSBAD RACEWAY - LOT 17
CARLSBAD, CALIFORNIA
DATE 10-06-2010 PROJECT NO. 07349 - 42 - 11 FIG. 1
Vicintfy Map
CARLSBAD RACEWAY - LOT 17
CARLSBAD, CALIFORNIA
SCALE: r = 60-
GEOCON LEGEND
..COMPACTED FILL
^ * TSd SANTIAGO FORMATK3N (Dolled Where Suited)
• APPROX. LOCATION OF EXPLORATORY BORING
APPROX LOCATION OF FAULT
APPROX. LOCATION OF SUBORAM
.A. APPROX. ELEVATION OF SUBDRAIN
I
, BE] APPROX. ELEVATION AT BOTTOM OF NATIVE
SOIL REMOVAL
GEOCON
INCOIlPOnATED
GfOTEQINCAl CONSUITANTS 6960 FLAM3WS DSIVt - SAN tXGO, C»UfOSMA 92131 - 2974 PHOrC 858 Si»-tiVO0 - FAX US iiH)\59
PROJECT NO. 07349 • 42 - 11
SITE PLAN DATE 10-06-2010
CONCRETE Sl-AB
SAND
MOISTURE INHIBITOR
(WHERE REQUIRED)
..v-fV .... ...-^ ..
''<'K.^33^'
FOOTING*
WIDTH
PAD GRADE
il K Q. O O D
-I V
CONCRETE SLAB
SAND
MOISTURE INHIBITOR
(WHERE REQUIRED)
...X.. ..V.
1)1
: .V- ..v:..-- ......^.
" - • : - v. P .•.4v; VI' J.' . . . V.^. •i' , ^ .... •»•. •
FOOTING WIDTH-
....SEE REPORT FOR FOUNDATION WITDH AND DEPTH RECOMMENDATION NO SCALE
WALL / COLUMN FOOTING DIMENSION DETAIL
GEOCON ^
INCORPORATED ^^V^
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
CARLSBAD RACEWAY - LOT 17
CARLSBAD, CALIFORNIA
AS/AML j DSK/GTYPD DATE 10-06-2010 PROJECT NO. 07349-42- 11 | FIG. 3
COLFOOI2DWG
GROUND SURFACE
CONCRETE
BROWDITCH
PROPOSED
RETAINING WALL
TEMPORARY BACKCUT
PER OSHA
GROUND SURFACE
MIRAFI 140N FILTER FABRIC
(OR EQUIVALENT)
OPEN GRADED
r MAX. AGGREGATE
4- DIA. PERFORATED SCHEDULE
40 PVC PIPE EXTENDED TO
APPROVED OUTLET
GROUND SURFACE
CONCRETE
BROWDITCH
WATER PROOFING
PER ARCHITECT
DRAINAGE PANEL (MIF?ADRAIN 6000
OR EQUIVALENT)
3/4" CRUSHED ROCK
(1 CU.FT./FT.)
FILTER FABRIC ENVELOPE
MIRAFI HON OR EQUIVALENT
4- DIA. SCHEDULE 40 PERFORATED
PVC PIPE OR APPROVED TOTAL DRAIN
EXTENDED TO APPROVED OUTLET
FOOTING
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
GEOTECHNICAL CONSULTANTS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
TR/RA DSK/GTYPD
CARLSBAD RACEWAY - LOT 17
CARLSBAD, CALIFORNIA
DATE 10-06-2010 I PROJECT NO, 07349 - 42 - 11 I FIG. 4
APPENDIX
APPENDIX A
FIELD INVESTIGATION
The field investigation was perfonned on September 15, 2010, and consisted of drilling six small-
diameter borings at the approximate locations shown on Figure 2. The borings were drilled to a
maximum depth of 19.5 feet below existing grade using a CME-55 truck-mounted drill rig equipped
with 8-inch-diameter hollow-stem augers. Relatively undisturbed samples were obtained with the
drill rig by driving a 3-inch O. D., split-Uibe sampler 12 inches into the undismrbed soil mass with
blows from a 140-pound hammer falling 30 inches. The split-tube sampler was equipped with 1-inch-
high by 2/4-inch-diameter brass sampler rings to facilitate sample removal and testing.
The soil conditions encountered in the borings were visually examined, classified and logged in
general confonnance with the American Society for Testing and Materials (ASTNf) Practice for
Description and Identification of Soils (Visual-Manual Procedure D2488). The logs of the
exploratory borings are presented on Figures A-1 through A-6. The logs depict the various soil types
encountered and indicate the depths at which samples were obtained.
Project No. 07349-42-11 October 6. 2010
PROJECT NO. 07349-42-11
DEPTH
IN
FEET
SAMPLE
NO.
SOIL
CLASS
(USCS)
BORING B 1
ELEV. (MSL.) DATE COMPLETED 09-15-2010
EQUIPMENT CME55 BY: T. MYERS
2oi-b z y-
LI. I— > I- CO >
>-
CO ^
z u-
°^
Q
UJ £\
o z 5 O O
- 0
- 2
MATERIAL DESCRIPTION
Bl-I
- Bl-2
- 4 -
- 6 -
- 8
- 10
- 12 -
- 14
- 16
- 18 -
Bl-3
Bl-4
Bl-5
Bl-6
Bl-7
ML
CL
sc
(1.
ML
COMPACTED FILL
Stiff, damp, light brown. Clayey SILT with fine sand and gravel
-Very stiff, moist, orangish brown and gray. Clayey SILT with some fme sand
and gravel
-Very stiff, moist, yellowish brown to white. Clayey SILT with fine sand and
gravel
- 39
11
116.9
120.2
Very stiff, moist, mottled dark brown, gray, Sandy CLAY with siU
_2a
Medium dense, moist, mottled, yellowish brown, white and orange. Clayey,
fine SAND
Stiff, moist, mottled, orange brown, olive brown, gray, Silty CLAY with some
fine to medium sand
1(1
-Very stiff, moist, mottled dark brown, orange and gray, Silty CLAY with
some fme to medium sand
Very stiff, moist, mottled orange brown, brown, white. Clayey SILT with
some fme to medium sand 78/5'
13.1
12.9
BORING TERMINATED AT 19.9 FEET
No groundwater encountered
Figure A-1, 07349-42-11.GPJ
Log of Boring B 1, Page 1 of 1
D - SAMPLING UNSUCCESSFUL I] ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
SAMPLE SYMBOLS
I] ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED)
^ ... DISTURBED OR BAG SAMPLE B ...CHUNK SAMPLE 5 ... WATER TABLE OR SEEPAGE
NOTE THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED,
rr IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDDTONS AT OTHER LCXATIONS AND TIMES.
GEOCON
PROJECT NO. 07349-42-11
DEPTH
IN
FEET
SAMPLE
NO.
SOIL
CLASS
(USCS)
BORING B 2
ELEV. (MSL.) DATE COMPLETED 09-15-2010
EQUIPMENT CME55 BY: T. MYERS
2oi-
t: 2 y;
I- CO >
CO ^
z u-
u
cc
Q
o z 2 o o
MATERIAL DESCRIPTION
- 0
- 2
- 6 -
- 10 -
- 12 -
- 14
- 16 -
- M
B2-1
B2-2
B2-3
B2-4
B2-5
B2-6
B2-7
ML-CL
SM
ML
SM
Sf
CL
SM"
CL
sc"
COMPACTED FILL
Medium stiff damp, yellowish brown to dark brown. Sandy SILT and Silty
CLAY
_ 44
Medium dense, moist, orange brown, fine to medium Silly SAND
-Dense, moist, yellow brown and orange brown, fme to coarse Silty SAND
with gravel
Very stiff, moist, orange brown, Sandy SILT with some clay
-Very stiff moist, yellow brown and gray. Clayey SILT with some fme to
medium sand
_ 42
Medium dense, moist, yellowish brown, orange brown and gray. SiUy, fine to
medium SAND
38
Medium dense, moist, orange brown. Clayey SAND
Stiff moist, gray, Silty CLAY
Medium dense, moist, orange brown and gray, Silty, fine to medium SAND 3.^
Stiff, moist, dark brown to dark gray, Silty CLAY
Medium dense, moist, orange brown, Clayey, fine to medium SAND
BORING TERMINATED AT 19.9 FEET
No groundwater encountered
114.0
116.4
16.3
15.3
Figure A-2,
Log of Boring B 2, Page 1 of 1
07349-42-11.GPJ
^ „ D - SAMPLING UNSUCCESSFUL
SAMPLE SYMBOLS
^ ... DISTURBED OR BAG SAMPLE
B ... STANDARD PENETRATION TEST
S ... CHUNK SAMPLE
1 ... DRIVE SAMPLE (UNDISTURBED)
J ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONOmONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED.
mS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. 07349-42-11
DEPTH
IN
FEET
SAMPLE
NO.
SOIL
CLASS
(USCS)
BORING B 3
ELEV. (MSL.) DATE COMPLETED 09-15-2010
EQUIPMENT CME55 BY: T. MYERS
b: z y-
I- CO > i^JoO
;UJ:
CO '~. Z U-
> cc n
Q-
- 0
MATERIAL DESCRIPTION
B3-1
- 2 -
- B3-2
- 4 -
- 6
- 10 -
12 -
- 14
- 16 -
- 18 -
B3-3
B3-4
B3-5
B3-6
B3-7
CL
SM
ML
SM
CL
ML
COMPACTED FILL
Stiff damp to slightly moist. Silty CLAY
Medium dense, moist, mottled orange brown and white, Silty, fme to medium
SAND; rock in shoe
-Medium dense, moist, orange brown, Silty, fine SAND
Stiff, moist, olive brown, Clayey SILT
Medium dense, moist, orange brown and yellow brown, Silty. fine SAND
- 54
43
32
Very stiff, moist, gray, Silty CLAY with some fine to coarse sand
37
Very stiff, moist, olive brown and gray. Clayey SILT with some sand
114.8
108.1
16.5
19.5
BORING TERMINATED AT 19.9 FEET
No groundwater encountered
Figure A-3,
Log of Boring B 3, Page 1 of 1
07349-42-11.GPJ
D ••• SAMPLING UNSUCCESSFUL
SAMPLE SYMBOLS
^ ... DISTURBED OR BAG SAMPLE
H ... STANDARD PENETRATION TEST
B ... CHUNK SAMPLE
1 ... DRIVE SAMPLE (UNDISTURBED)
I ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED,
rr IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDmONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. 07349-42-11
DEPTH
IN
FEET
SAMPLE
NO.
SOIL
CLASS
(USCS)
BORING B 4
ELEV. (MSL.) DATE COMPLETED 09-15-2010
EQUIPMENT CME55 BY: T. MYERS
H CO >
LU UJ CO
CL tr
CO -T Z LJ-
01 Q
UJ
O Z 5 O O
MATERIAL DESCRIPTION
- 0
- 2 -
- 4
- 6 -
- 10 -
12
- 14 -
- 16 -
- 18 -
B4-1
B4-2
B4-3
B4-4
B4-5
CL
SM
7 ,
//I
B4-6
B4-7
CL
ivir
CL-ML
ML
COMPACTED FILL
Stiff, damp to slightly moist, olive brown, Silty CLAY
Medium dense, moist, yellow brown and gray brown, Silty, fine to coarse
SAND with gravel; sample disturbed
-Medium dense, moist, mottled orange brown, gray, white, Silty, fine lo
medium SAND with some clay
-78/1 r
14
_22
111.5
113.0
Stiff, moist, dark olive brown, fine to coarse Sandy CLAY
Stifi". moist, mottled gray, orange brciwn, white, Sandy SILT with little clay
,5:
Very stiff, moist, dark brown, Silty CLAY and orange brown. Clayey SILT
2')
Stiff, slightly moist, mottled yellow brown, orange brown, gray and white,
fine Sandy SILT
-Stiff, moist, mottled yellow brown, orange brown, white. Clayey SILT VI
17.4
17.8
BORING TERMINATED AT 19.9 FEET
No groundwater encountered
Figure A-4,
Log of Boring B 4, Page 1 of 1
07349-42-11.GPJ
0 •• SAMPLING UNSUCCESSFUL
SAMPLE SYMBOLS
^ ... DISTURBED OR BAG SAMPLE
H ... STANDARD PENETRATION TEST
B ... CHUNK SAMPLE
1 .. DRIVE SAMPLE (UNDISTURBED)
^ ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED,
IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONOmONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. 07349-42-11
DEPTH
IN
FEET
SAMPLE
NO.
SOIL
CLASS
(USCS)
BORING B 5
ELEV. (MSL.) DATE COMPLETED 09-15-2010
EQUIPMENT CME55 BY: T. MYERS
b 2 LL
I- CO >
CO T Z li-
cc
Q
O Z
5 O
o
MATERIAL DESCRIPTION
B5-1
- B5-2
ML
•
- 4 -
- 6 -
- 10 -
B5-3
B5-4
B5-5
CL
( 1.-.\1L
ML
SM
ML
rOMP.\CTED FILL
Stiff, damp to slightly moist. Clayey SILT with some sand
Hard, moist, orange brown and gray, Silty CLAY with some fine to coarse
sand _ 48 123.1
Stiff, moist, olive brown to dark brown, Silty CLAY and Clayey SILT with
some sand
30
-41
114.1
Very stiff, moist, greenish brown and orange brown. Clayey SILT; sample
disOirbed duejopvcpipe_ _ j
Dense, moist, yellow brown, Silty, fine to coarse SAND
Very stiff, moist, mottled gray, olive brown, orange brown. Clayey SILT with
some sand /
BORING TERMINATED AT 11 FEET
No groundwater encountered
34
12.4
17.3
Figure A-5,
Log of Boring B 5, Page 1 of 1
07349-42-11.GPJ
D •• SAMPLING UNSUCCESSFUL
SAMPLE SYMBOLS
S • DISTURBED OR BAG SAMPLE
|] ... STANDARD PENETRATION TEST
B ...CHUNK SAMPLE
1 ... DRIVE SAMPLE (UNDISTURBED)
I ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED,
rr IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONOmONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. 07349-42-11
DEPTH
IN
FEET
SAMPLE
NO.
SOIL
CLASS
(USCS)
BORING B 6
ELEV. (MSL.) DATE COMPLETED 09-15-2010
EQUIPMENT CME55 BY: T. MYERS
2 oi-
I- CO >
^cog
CO ^ Z LL u
CL Q
UJ ^\
o z 2 O o
MATERIAL DESCRIPTION
- 0 B6-1
- 2 -
- B6-2
- 4 -
- 6 -
ML-CL COMPACTED FILL
Stiff damp to slightly moist, dark yellowish brown. Clayey SILT and Silty
CLAY
-42, LLL5 1Z9- -
SM
- 10 -
B6-3
B6-4
B6-5
ML
Dense, moist, yellowish brown, orange brown, Silty, fine to medium SAND
with little gravel
-Medium dense, moist, orange brown. Silty, fine to medium SAND
Stiff, moist, orange brown and gray, Sandy SILT
-Stiff, moist, olive brown, Sandy SILT
32 15.8 15.9
- 34
BORING TERMINATED AT 11 FEET
No groundwater encountered
Figure A-6,
Log of Boring B 6, Page 1 of 1
07349-42-11.GPJ
D ..• SAMPLING UNSUCCESSFUL
SAMPLE SYMBOLS
^ ... DISTURBED OR BAG SAMPLE
B ... STANDARD PENETRATION TEST
B ... CHUNK SAMPLE
1 ... DRIVE SAMPLE (UNDISTURBED)
% ... WATER TABLE OR SEEPAGE
NOTE THE LOG OF SUBSURFACE CONDmONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LCDCATION AND AT THE DATE INDICATED,
rr IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDmONS AT OTHER LCXATIONS AND TIMES.
GEOCON
APPENDIX <
APPENDIX B
LABORATORY TESTING
Laboratory tests were performed in accordance with generally accepted test methods of the American
Society for Testing and Materials (ASTM) or other suggested procedures. Selected soil samples were
tested for their in-place dry density and moisture content, maximum dry density and optimum moisture
content, expansion potential, pH, resistivity, soluble sulfate content, and consolidation characteristics. The
results of our laboratory tests are presented on Tables B-I througli B-IV and Figure B-1.
TABLE B-1
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND
OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM D 1557
Sample No. Description Maximum
Dry Density (pcf)
Optimum
Moisture Content
(% dry wt.)
B2-1 Olive Brown, fine Sandy CLAY 123.3 11.3
B3-1 Yellowi-sh-brown, fine to medium Sandy CLAY 125.1 11.0
TABLE B-il
SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS
ASTM D 4829
Sample No.
Moisture Content Dry Density
(pcO
Expansion
Index Classification Sample No.
Before Test (%) After Test (%)
Dry Density
(pcO
Expansion
Index Classification
B2-1 10.1 23.5 105.7 66 Medium
B3-1 10.5 21.0 107.7 50 Low
B4-1 11.7 23.4 105.5 60 Medium
TABLE B-lll
SUMMARY OF LABORATORY pH AND RESISTIVITY TEST RESULTS
CALIFORNIA TEST NO. 643
Sample No. pH Minimum Resistivity
(ohm-centimeters)
B3-1 8.1 560
B5-1 8.2 510
Project No. 07349-42-11 - B-1 -October 6, 2010
TABLE B-IV
SUMMARY OF LABORATORY SULFATE CONTENT RESULTS
CALIFORNIA TEST NO. 417
Sample No. Sulfate (% S04) Sulfate Exposure
B2-1 0.526 Severe
B-1 0.442 Severe
B4-1 0.683 Severe
Project No. 07349-42-11 - B-2-October6, 2010
PROJECT NO. 07349-42-11
SAMPLE NO. 81-2
UJ
U
a-
0 .1 1 10
APPLIED PRESSURE (ksf)
Initial Dry Density (pcf) 116.9
Initial Water Content (%) 13.1
no
Initial Saturation (%) 83.2
Sample Saturated at (ksf) .5
CONSOUDATION CURVE
CARLSBAD RACEWAY-LOT 17
CARLSBAD, CAUFORNIA
07349-42-11.GPJ Figure B-1
GEOCON
APPENDIX
APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
PREPARED FOR
CARLSBAD RACEWAY
BUSINESS PARK - LOT 17
CARLSBAD, CALIFORNIA
PROJECT 07349-42-11
RECOMMENDED GRADING SPECIFICATIONS
1. GENERAL
1.1 These Recommended Grading Specifications shall be used in conjunction with the
Geotechnical Report for the project prepared by Geocon Incorporated. The
recommendations contained in the text of the Geotechnical Report are a part of the
earthwork and grading specifications and shall supersede the provisions contained
hereinafter in the case of conflict.
1.2 Prior to the commencement of grading, a geotechnical consultant (Consultant) shall be
employed for the purpose of observing earthwork procedures and testing the fills for
substantial confonnance with the recommendations of the Geotechnical Report and these
specifications. The Consultant should provide adequate testing and observation services so
that they may assess whether, in their opinion, the work was performed in substantial
conformance with these specifications. It shall be the responsibility of the Contractor to
assist the Consultant and keep thein apprised of work schedules and changes so that
personnel may be scheduled accordingly.
1.3 It shall be the sole responsibility of the Contractor to provide adequate equipment and
methods to accomplish the work m accordance with applicable grading codes or agency
ordinances, these specifications and the approved grading plans. If, in the opinion of the
Consultant, unsatisfactory conditions such as questionable soil materials, poor moismre
condition, inadequate compaction, adverse weather, result in a quality of work not in
conformance with these specifications, the Consultant will be empowered to reject the
woric and recommend to the Owner that grading be stopped until the unacceptable
conditions are corrected.
2. DEFINmONS
2.1 Owner shall refer to the owner of the property or the entity on whose behalf the grading
work is being perfonned and who has contracted with the Contractor to have grading
performed.
2.2 Contractor shall refer to the Contractor perfonning the site grading work.
2.3 Civil Engineer or Engineer of Work shall refer to the Califomia licensed Civil Engineer
or consulting firm responsible for preparation of the grading plans, surveying and verifying
as-graded topography.
GI rev. 04/2009
2.4 Consultant shall refer to the soil engineering and engineering geology consulting firm
retained to provide geotechnical services for the project.
2.5 Soil Engineer shall refer to a California licensed Civil Engineer retained by the Owner,
who is experienced in the practice of geotechnical engineering. The Soil Engineer shall be
responsible for having qualified representatives on-site to observe and test the Contractor's
work for confonnance with these specifications.
2.6 Engineering Geologist shall refer to a California licensed Engineering Geologist retained
by the Owner to provide geologic observations and recommendations during the site
grading.
2.7 Geotechnical Report shall refer to a soil report (including all addenda) which may include
a geologic reconnaissance or geologic investigation that was prepared specifically for the
development of the project for which these Recommended Grading Specifications are
intended to apply.
3. MATERIALS
3.1 Materials for compacted fill shall consist of any soil excavated from the cut areas or
imported to the site that, in the opinion of the Consultant, is suitable for use in construction
of fills. In general, fill materials can be classified as soil fills, soil-rock fills or rock fills, as
defined below.
3.1.1 Soil fills are defined as fills containing no rocks or hard lumps greater than 12
inches in maximum dimension and containing at least 40 percent by weight of
material smaller than VA inch in size.
3.1.2 Soil-rock fills are defined as fills containing no rocks or hard lumps larger than 4
feet in maximum dimension and containing a sufficient matrix of soil fill to allow
for proper compaction of soil fill around the rock fragments or hard lumps as
specified in Paragraph 6.2. Oversize rock is defined as material greater than 12
inches.
3.1.3 Rock fills are defined as fills containing no rocks or hard lumps larger dian 3 feet
in maximum dimension and containing little or no fines. Fines are defined as
material smaller than VA inch in maximum dimension. The quantity of fines shall be
less than approximately 20 percent of the rock fill quantity.
GI rev. 04/2009
3.2 Material of a perishable, spongy, or otherwise unsuitable nature as determined by the
Consultant shall not be used in fills.
3.3 Materials used for fill, either imported or on-site, shall not contain hazardous materials as
defmed by the Califomia Code of Regulations, Title 22, Division 4, Chapter 30, Articles 9
and 10; 40CFR; and any other applicable local, state or federal laws. The Consultant shall
not be responsible for the identification or analysis of the potential presence of hazardous
materials. However, if observations, odors or soil discoloration cause Consultant to suspect
the presence of hazardous materials, the Consultant may request from the Owner the
termination of grading operations within the affected area. Prior to resuming grading
operations, the Owner shall provide a written report to the Consultant indicating that the
suspected materials are not hazardous as defined by applicable laws and regulations.
3.4 The outer 15 feet of soil-rock fill slopes, measured horizontally, should be composed of
properly compacted soil fill materials approved by the Consultant. Rock fill may extend to
the slope face, provided that the slope is not steeper than 2:1 (horizontahvertical) and a soil
layer no thicker than 12 inches is track-walked onto the face for landscaping purposes. This
procedure may be utilized provided it is acceptable to the governing agency, Owner and
Consultant.
3.5 Samples of soil materials to be used for fill should be tested in the laboratory by the
Consultant to determine the maximum density, optimum moisture content, and, where
appropriate, shear strength, expansion, and gradation characteristics ofthe soil.
3.6 During grading, soil or groundwater conditions other than those identified in the
Geotechnical Report may be encountered by the Contractor. The Consultant shall be
notified immediately to evaluate the significance of the unanticipated condition
4. CLEARING AND PREPARING AREAS TO BE FILLED
4.1 Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of
complete removal above the ground surface of trees, stumps, bmsh, vegetation, man-made
stmctures, and similar debris. Grubbing shall consist of removal of smmps, roots, buried
logs and other unsuitable material and shall be perfonned in areas to be graded. Roots and
other projections exceeding 1 Vi inches in diameter shall be removed to a depth of 3 feet
below the surface of the ground. Bonow areas shall be gmbbed to the extent necessary to
provide suitable fill materials.
GI rev. 04/2009
4.2 Any asphalt pavement material removed during clearing operations should be properly
disposed at an approved off-site facility. Concrete fragments that are free of reinforcing
steel may be placed in fills, provided they are placed in accordance with Section 6.2 or 6.3
of this document.
4.3 After clearing and grubbing of organic matter and other unsuitable material, loose or
porous soils shall be removed to the depth recoinmended in the Geotechnical Report. The
depth of removal and compaction should be observed and approved by a representative of
the Consultant. The exposed surface shall then be plowed or scarified to a minimum depth
of 6 inches and until the surface is free from uneven features that would tend to prevent
uniform compaction by the equipment to be used.
4.4 Where the slope ratio of the original ground is steeper than 5:1 (horizontal:vertical), or
where recommended by the Consultant, the original ground should be benched in
accordance with the following illustration.
TYPICAL BENCHING DETAIL
Finish Grade Original Ground
Remove All
Unsuitable Material
As Recommended By
Consultant Slope To Be Such That
Sloughing Or Sliding
Does Not Occur
Finish Slope Surface
See Note 2 _
No Scale
DETAIL NOTES: (1) Key width "B" should be a minimum of 10 feet, or sufficiently wide to permit
complete coverage with the compaction equipment used. The base of the key should
be graded horizontal, or inclined slightly into the natural slope.
(2) The outside of the key should be below the topsoil or unsuitable surficial material
and at least 2 feet into dense formational material. Where hard rock is exposed in the
bottom of the key, the depth and configuration of the key may be modified as
approved by the Consultant.
GI rev. 04/2009
4.5 After areas to receive fill have been cleared and scarified, the surface should be moisture
conditioned to achieve the proper moisture content, and compacted as recommended in
Section 6 of these specifications.
5. COMPACTION EQUIPMENT
5.1 Compaction of soil or soil-rock fill shall be accomplished by sheepsfoot or segmented-steel
wheeled rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of
acceptable compaction equipment. Equipment shall be of such a design that it will be
capable of compacting the soil or soil-rock fill to the specified relative compaction at the
specified moisture content.
5.2 Compaction of rock fills shall be performed in accordance with Section 6.3.
6. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL
6.1 Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Contractor in accordance with
the following recommendations:
6.1.1 Soil fill shall be placed by the Contractor in layers that, when compacted, should
generally not exceed 8 inches. Each layer shall be spread evenly and shall be
thoroughly mixed during spreading to obtain uniformity of material and moisture
in each layer. The entire fill shall be constmcted as a unit in nearly level lifts. Rock
materials greater than 12 inches in maximum dimension shall be placed in
accordance with Section 6.2 or 6.3 of these specifications.
6.1.2 In general, the soil fill shall be compacted at a moisture content at or above the
optimum moisture content as determined by ASTM D 1557-02.
6.1.3 When the moisture content of soil fill is below that specified by the Consultant,
water shall be added by the Contractor until the moisture content is in the range
specified.
6.1.4 When the moisture content of the soil fill is above the range specified by the
Consultant or too wet to achieve proper compaction, the soil fill shall be aerated by
the Contractor by blading/mixing, or other satisfactory methods until the moisture
content is within the range specified.
GI rev. 04/2009
6.1.5 After each layer has been placed, mixed, and spread evenly, it shall be thoroughly
compacted by the Contractor to a relative compaction of at least 90 percent.
Relative compaction is defined as the ratio (expressed in percent) of the in-place
dry density of the compacted fill to the maximum laboratory dry density as
detemiined in accordance with ASTM D 1557-02. Compaction shall be continuous
over the entire area, and compaction equipment shall make sufficient passes so that
the specified minimum relative compaction has been achieved throughout the
entire fill.
6.1.6 Where practical, soils having an Expansion Index greater than 50 should be placed
at least 3 feet below finish pad grade and should be compacted at a moisture
content generally 2 to 4 percent greater than the optimum moisture content for the
material.
6.1.7 Properly compacted .90// fill shall extend to the design surface of fill slopes. To
achieve proper compaction, it is recommended that fill slopes be over-built by at
least 3 feet and then cut to the design grade. This procedure is considered
preferable to track-walking of slopes, as described in the following paragraph.
6.1.8 As an alternative to over-building of slopes, slope faces may be back-rolled with a
heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height
intervals. Upon completion, slopes should then be track-walked with a D-8 dozxjr
or similar equipment, such that a dozer track covers all slope surfaces at least
twice.
6.2 Soil-rock fiW, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance
with the following recommendations:
6.2.1 Rocks larger than 12 inches but less than 4 feet in maximum dimension may be
incorporated into the compacted soil fill, but shall be limited to the area measured
15 feet minimum horizontally from the slope face and 5 feet below finish grade or
3 feet below the deepest utility, whichever is deeper.
6.2.2 Rocks or rock fragments up to 4 feet in maximum dimension may either be
individually placed or placed in windrows. Under certain conditions, rocks or rock
fragments up to 10 feet in maximum dimension may be placed using similar
methods. The acceptability of placing rock materials greater than 4 feet in
maximum dimension shall be evaluated during grading as specific cases arise and
shall be approved by the Consultant prior to placement.
Gl rev. 04/2009
6.2.3 For individual placement, sufficient space shall be provided between rocks to allow
for passage of compaction equipment.
6.2.4 For windrow placement, die rocks should be placed in trenches excavated in
properly compacted soil fill. Trenches should be approximately 5 feet wide and
4 feet deep in maximum dimension. The voids around and beneath rocks should be
filled with approved granular soil having a Sand Equivalent of 30 or greater and
should be compacted by flooding. Windrows may also be placed utilizing an
"open-face" method in lieu of the trench procedure, however, this method should
first be approved by the Consultant.
6.2.5 Windrows should generally be parallel to each other and may be placed either
parallel to or perpendicular to the face of the slope depending on the site geometry.
The minimum horizontal spacing for windrows shall be 12 feet center-to-center
with a 5-foot stagger or offset from lower courses to next overlying course. The
minimum vertical spacing between windrow courses shall be 2 feet from the top of
a lower windrow to the bottom of the next higher windrow.
6.2.6 Rock placement, fill placement and flooding of approved granular soil in the
windrows should be continuously observed by the Consultant.
6.3 Rock fills, as defined in Section 3.1.3, shall be placed by the Contractor in accordance with
the following recommendations:
6.3.1 The base of the rock fill shall be placed on a sloping surface (minimum slope of 2
percent). The surface shall slope toward suitable subdrainage outlet facilities. The
rock fills shall be provided with subdrains during construction so that a hydrostatic
pressure buildup does not develop. The subdrains shall be permanently connected
to controlled drainage facilities to control post-constmction infiltration of water.
6.3.2 Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock
tmcks traversing previously placed lifts and dumping at the edge of the currently
placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the
rock. The rock fill shall be watered heavily during placement. Watering shall
consist of water tmcks traversing in front of the cunent rock lift face and spraying
water continuously during rock placement. Compaction equipment with
compactive energy comparable to or greater than that of a 20-ton steel vibratory
roller or other compaction equipment providing suitable energy to achieve the
GI rev. 04/2009
required compaction or deflection as recommended in Paragraph 6.3.3 shall be
utilized. The number of passes to be made should be determined as described in
Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional
rock fill lifts will be permitted over the soil fill.
6.3.3 Plate bearing tests, in accordance with ASTM D 1196-93, may be performed in
both the compacted .TO/7 fill and in the rock fill to aid in detennining the required
minimum number of passes of the compaction equipment. If performed, a
minimum of three plate bearing tests should be perfonned in die properly
compacted soil fill (minimum relative compaction of 90 percent). Plate bearing
tests shall then be perfonned on areas of rock fill having two passes, four passes
and six passes of the compaction equipment, respectively. The number of passes
required for the rock fill shall be determined by comparing the results of the plate
bearing tests for the soU fill and the rock fill and by evaluating the deflection
variation with number of passes. The required number of passes of the compaction
equipment will be perfonned as necessary until the plate bearing deflections are
equal to or less than that determined for the properly compacted .TO/7 fill. In no case
will the required number of passes be less than two.
6.3.4 A representative of the Consultant should be present during rock fill operations to
observe that the minimum number of "passes" have been obtained, that water is
being properly applied and that specified procedures are being followed. The actual
number of plate bearing tests will be detennined by the Consultant during grading.
6.3.5 Test pits shall be excavated by the Contractor so that the Consultant can state that,
in their opinion, sufficient water is present and that voids between large rocks are
properly filled with smaller rock material. In-place density testing will not be
required in the rock fills.
6.3.6 To reduce the potential for "piping" of fines into the rock fill from overlying sod
fill material, a 2-foot layer of graded filter material shall be placed above the
uppermost lift of rock fill. The need to place graded filter material below the rock
should be determined by the Consultant prior to commencing grading. The
gradation of the graded filter material will be detennined at the time the rock fill is
being excavated. Materials typical of the rock fill should be submitted to the
Consultant in a timely manner, to allow design of the graded filter prior to the
commencement of rock fill placement.
6.3.7 Rock fill placement should be continuously observed during placement by the
Consultant.
GI rev. 04/2009
7. OBSERVATION AND TESTING
7.1 The Consultant shall be the Owner's representative to observe and perforin tests during
clearing, gmbbing, filling, and compaction operations. In general, no more than 2 feet in
vertical elevation of sod or soil-rock fill should be placed without at least one field density
test being performed within that interval. In addition, a minimum of one field density test
should be performed for every 2,000 cubic yards of soil or soil-rock fill placed and
compacted.
7.2 The Consultant should perfonn a sufficient distribution of field density tests of the
compacted sod or soil-rock fill to provide a basis for expressing an opinion whether the fill
material is compacted as specified. Density tests shall be perfonned in the compacted
materials below any disturbed surface. When these tests indicate that the density of any
layer of fill or portion thereof is below that specified, the particular layer or areas
represented by the test shall be reworked until the specified density has been achieved.
7.3 During placement of rock fill, the Consultant should observe that the minimum number of
passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant
should request the excavation of observation pits and may perform plate bearing tests on
the placed rock fills. The observation pits will be excavated to provide a basis for
expressing an opinion as to whether the rock fill is properly seated and sufficient moisture
has been applied to the material. When observations indicate that a layer of rock fill or any
portion thereof is below that specified, the affected layer or area shall be reworked until the
rock fill has been adequately seated and sufficient moisture applied.
7.4 A settlement monitoring program designed by the Consultant may be conducted in areas of
rock fill placement. The specific design of the monitoring program shall be as
recommended in the Conclusions and Recommendations section of the project
Geotechnical Report or in the final report of testing and observation services perfonned
during grading.
7.5 The Consultant should observe the placement of subdrains, to verify that the drainage
devices have been placed and constmcted in substantial conformance with project
specifications.
7.6 Testing procedures shall con fomi to the following Standards as appropriate:
GI rev. 04/2009
7.6.1 Soil and Soil-Rock Fills:
7.6.1.1 Field Density Test, ASTM D 1556-02, Density of Soil In-Place By the
Sand-Cone Method.
7.6.1.2 Field Density Test, Nuclear Method, ASTM D 6938-08A, Density of Sod
and Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth).
7.6.1.3 Laboratory Compaction Test, ASTM D 1557-02, Moisture-Density
Relations of Sods and Soil-Aggregate Mixtures Using 10-Pound
Hammer and 18-Inch Drop.
7.6.1.4. Expansion Index Test, ASTM D 4829-03, Expansion Index Test.
7.6.2 Rock Fills
7.6.2.1 Field Plate Bearing Test, ASTM D 1 196-93 (Reapproved 1997)
Standard Method for Nonreparative Static Plate Load Tests of Soils and
Flexible Pavement Components, For Use in Evaluation and Design of
Airport and Highway Pavements.
8. PROTECTION OF WORK
During construction, the Contractor shall properly grade all excavated surfaces to provide
positive drainage and prevent ponding of water. Drainage of surface water shall be
controlled to avoid damage to adjoining properties or to finished work on the site. The
Contractor shall take remedial measures to prevent erosion of freshly graded areas until
such time as permanent drainage and erosion control features have been installed. Areas
subjected to erosion or sedimentation shall be properly prepared in accordance with the
Specifications prior to placing additional fill or stmctures.
After completion of grading as observed and tested by the Consultant, no further
excavation or filling shall be conducted except in conjunction with the services of the
Consultant.
GI rev. 04/2009
9. CERTIFICATIONS AND FINAL REPORTS
9.1 Upon completion of the work. Contractor shall furnish Owner a certification by the Civil
Engineer stating that the lots and/or building pads are graded to within 0.1 foot vertically of
elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot
horizontally of the positions shown on the grading plans. After installation of a section of
subdrain, the project Civil Engineer should survey its location and prepare an as-built plan
of the subdrain location. The project Civil Engineer should verify the proper outlet for the
subdrains and the Contractor should ensure that the drain system is free of obstmctions.
9.2 The Owner is responsible for furnishing a final as-graded soil and geologic report
satisfactory to the appropriate governing or accepting agencies. The as-graded report
should be prepared and signed by a Cahfomia licensed Civil Engineer experienced in
geotechnical engineering and by a Califomia Certified Engineering Geologist, indicating
that the geotechnical aspects of the grading were performed in substantial confonnance
with the Specifications or approved changes to the Specifications.
GI rev. 04/2009