HomeMy WebLinkAboutSDP 16-15; VICTORY CARLSBAD OAKS LOT 5; GEOTECHNICAL REPORT; 2016-06-24UPDATE
GEOTECHNICAL REPORT
CARLSBAD OAKS
NORTH BUSINESS PARK - LOT 5
CARLSBAD, CALIFORNIA
PREPARED FOR
BADIEE DEVELOPMENT INC.
LA JOLLA, CALIFORNIA
FEB 16 2017
LAND DEVELOPMENT
ENGINEERING
JUNE 24, 2016
PROJECT NO. 06442-42-27
I
[I
GEOCON
INCORPORATED
GEOTECHNICAL a ENVIRONMENTAL a
AX k
I
Project No. 06442-42-27
June 24, 2016
Badiee Development Inc.
P. 0. Box 3111
La Jolla, California 92038
Attention: Mr. John Couvillion
I Subject: UPDATE GEOTECHNICAL REPORT I CARLSBAD OAKS NORTH BUSINESS PARK - LOT 5
CARLSBAD, CALIFORNIA
I Dear Mr. Couvillion:
I In accordance with your request, and our Proposal No. LG-16180, dated May 20, 2016, we have
prepared this update geotechnical report for the continued development of the subject lot. The
accompanying report presents the findings of our study and, our conclusions and recommendations
I pertaining to the geotechnical aspects of project development.
We understand the proposed project includes fine grading the existing sheet-graded pad to support an
office/industrial building along with associated improvements. Based on the results of this study, it is I our opinion that the subject lot can be developed as planned, provided the recommendations of this
report are followed.
I If there are any questions regarding this update report, or if we may be of further service, please
contact the undersigned at your convenience.
I Very truly yours,
GEOCON INCORPORATED
Emilio Alvarado Rodh~h~eC. Mikesell David B. Evan
RCE66915 GEk25'33 CEG 1860
I EA:RCM:DBE:dmc
DAMID
EVAN OR S LU (D N0.2533 No. M915 M CERnF1
-T (P ENGINEE I
i 6960 Flanders Drive 13 Son Diego, California 92121-2974 13 Telephone 858.558.6900 13 Fax 858.558.6159
I
I
I
I
I TABLE OF CONTENTS
I
I. PURPOSE AND SCOPE ................................................................................................................. 1
PREVIOUS SITE DEVELOPMENT..............................................................................................1
SITE AND PROJECT DESCRIPTION ..........................................................................................2
SOIL AND GEOLOGIC CONDITIONS ........................................................................................ 3 ' 4.1 Compacted Fill (Qcf) ............................................................................................................3
4.2 Granitic Rock (Kgr) ..............................................................................................................3
I
RIPPABILITY AND ROCK CONSIDERATIONS........................................................................4
6. GROUNDWATER..........................................................................................................................4
1 7. GEOLOGIC HAZARDS .................................................................................................................5
7.1 Faulting .................................................................................................................................5
7.2 Seismicity-Deterministic Analysis........................................................................................5
I 7.3 Seismicity-Probabilistic Analysis..........................................................................................6
7.4 Landslides..............................................................................................................................6
7.5 Liquefaction ..........................................................................................................................7
I 7.6 Tsunamis and Seiches ...........................................................................................................7
8. CONCLUSIONS AND RECOMMENDATIONS ..........................................................................8
I 8.1
8.2
General ..................................................................................................................................8
Soil Characteristics................................................................................................................9
8.3 Subdrains.............................................................................................................................10
I
8.4
8.5
Grading................................................................................................................................10
Slopes..................................................................................................................................13
8.6 Seismic Design Criteria.......................................................................................................13
I
8.7
8.8
Foundation and Concrete Slab-On-Grade Recommendations ............................................15
Retaining Walls and Lateral Loads Recommendations.......................................................17
8.9 Mechanically Stabilized Earth (MSE) Retaining Walls......................................................19
8.10 Preliminary Pavement Recommendations - Flexible and Rigid.........................................21
8.11 Detention Basin and Bioswales Recommendations............................................................24 I 8.12 Site Drainage and Moisture Protection ...............................................................................25
8.13 Slope Maintenance..............................................................................................................26
8.14 Grading, Foundation, and Retaining Wall Plan Review .....................................................26
LIMITATIONS AND UNIFORMITY OF CONDITIONS
I MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
I
Figure 2, Geologic Map (Map Pocket)
Figure 3, Geologic Cross Sections A-A' and B-B' (Map Pocket)
Figure 4, Wall/Column Footing Dimension Detail
Figure 5, Typical Retaining Wall Drain Detail
I APPENDIX A
FIELD INVESTIGATION
1
Figures A-i - A-6, Logs of Exploratory Trenches
I
H
I
TABLE OF CONTENTS (Concluded)
APPENDIX B
I LABORATORY TESTING (Geocon Incorporated, 2006)
APPENDIX C
City of Carlsbad BMP Design Manual - Categorization of Infiltration Feasibility Condition
I (Form 1-8)
APPENDIX D
RECOMMENDED GRADING SPECIFICATIONS
I
I
I
I
I
I
I
I
I
Li
I
I
I
I
I
I UPDATE GEOTECHNICAL REPORT
I
I. PURPOSE AND SCOPE
This report presents the results of an update geotechnical study for the proposed ultimate
I
development of Lot 5 located in the Carlsbad Oaks North Business Park in Carlsbad, California (see
Vicinity Map, Figure 1). The purpose of this report was to evaluate the soil and geologic conditions
within the site and provide specific geotechnical recommendations pertaining to the development of
1 the property as proposed.
I The scope of our study included a site visit to observe whether the lot is in essentially the same
conditions as it was at the completion of mass grading and, review of the following reports and plan
i
specific to the project:
1. Final Report of Testing and Observation Services During Construction of Site Improvements,
I Carlsbad Oaks North, Business Park, Phase 1, Carlsbad, California, prepared by Geocon
Incorporated, dated May 28, 2008 (Project No. 06442-32-04B).
I
2. Final Report of Testing & Observation Services During Site Grading, Carlsbad Oaks North
Business Park - Phase 1, Lots 1 through 9, Carlsbad, California, prepared by Geocon
Incorporated, dated August 30, 2006 (Project No. 06442-32-04A).
I 3. Update Geotechnical Report, Carlsbad Oaks North Business Park - Lot 5, Carlsbad,
California, prepared by Geocon Incorporated, dated August 24, 2007 (Project No. 06442-
32-16).
1 . Conceptual Site Plan for Carlsbad Oaks Lot 5, Carlsbad, California, prepared by Smith
Consulting Architects, PDF copy, plot date June 3, 2016.
S We performed exploratory trenching on May 31, 2016, in areas where granitic rock was exposed at
grade across the pad. The purpose of the trenching was to obtain further information regarding near
I surface rock rippability. Logs of the exploratory trenches and other details of the field investigation
are presented in Appendix A.
The descriptions of the soil and geologic conditions and proposed development described herein is
I
based on review of the referenced reports and plan, and observations made during mass grading
operations for Lot 5 of the Carlsbad Oaks North Business Park development. Additional references
I
reviewed to prepare this report are provided in the List of References.
2. PREVIOUS SITE DEVELOPMENT
I Mass grading of Lot 5 was performed in conjunction with the compaction testing and observation
services of Geocon Incorporated. Test results, as well as professional opinions pertaining to the
I
Project No. 06442-32-27 - 1 - June 24, 2016
I
I
I grading of Lot 5, are summarized in Reference No. 2 (report dated August 30, 2006). Pertinent
laboratory tests performed on selected soil samples collected during previous grading are presented in
I Appendix B.
3. SITE AND PROJECT DESCRIPTION
I Lot 5 consists of an approximate 4-acre, previously sheet-graded vacant lot. The lot is bounded by
Whiptail Loop West to the west, Faraday Avenue to the south, Caribou Court to the north, and Lot 7
to the east.
I The existing as-graded condition of the property consists of compacted fill and granitic rock exposed at
grade. Ascending and descending 2:1 (horizontal:vertical) cut and fill slopes were constructed along the
perimeter of the lot with a maximum height of approximately 45 feet. The slopes are landscaped with I shrubs and trees with an active irrigation system to water the existing vegetation. Sparse low lying
grass/weeds are spread across the property.
Topographically, the sheet-graded pad portion of the lot slopes from the northeast to the southwest with
I elevations varying from approximately 345 feet above Mean Sea Level (MSL) to approximately
334 feet MSL at the bottom of a temporary detention basin located at the southwest corner of the pad.
Existing improvements within the lot consist of a storm drain system that was constructed as part of the
I temporary detention basin.
I The referenced site plan indicates the property will be developed to support an approximately 53,000
square foot, office/warehouse concrete tilt-up building with infrastructure improvements. The
building will be subdivided into individual units. We anticipate that the structure will be founded on
I conventional continuous, isolated spread foundations or appropriate combinations thereof with slab-
on-grade floors. We understand that the driveway traffic will consist of cars/light trucks, and heavy
I truck traffic. Fine grading is expected to consist of cuts and fills generally less than five feet to
achieve planned grade. Retaining walls with maximum height of approximately six feet are also
planned for the project. Proposed development includes constructing a Low Impact Development
I (LID)!bio-retention basins for storm water treatment.
I The descriptions contained herein are based upon the site reconnaissance and, a review of the
referenced reports and plan. If project details vary significantly from those outlined herein, Geocon
I Incorporated should be notified for review and possible revisions to this report prior to final design
submittal.
I
I
Project No. 06442-32-27 -2- June 24, 2016
I
1 4. SOIL AND GEOLOGIC CONDITIONS
Compacted fill and granitic bedrock are exposed at finish grade. These units are described below and
I their approximate lateral extent is shown on the Geologic Map (Figure 2) and the Geologic Cross
Sections (Figure 3).
4.1 Compacted Fill (Qcf)
' Compacted fill was placed across the lot during previous grading operations. The fill is underlain by
granitic rock and, where located on the sheet-graded portion of the lot, generally consists of a 3-foot-
thick cap of soil containing some 6-inch-minus rock. Fill below the soil cap contains rock fragments
up to 12 inches in size. Rocks larger than 12 inches in length and, generally between 2 to 4 feet in
maximum dimension were placed at least 10 feet below finish sheet grade in fill areas. In some
I instances, larger boulders were individually placed in the deeper fill areas. The outer approximately
15 feet of embankment slopes consist of soil fill with 6-inch-minus rock and occasional 12-inch
material. Although particular attention was given to restricting oversize rock placement as discussed
I herein, it is possible that some oversize material (> 12 inches) may be present in the upper portions of
fill areas. The presence of oversize rock should be considered during fine grading and where below-
grade improvements (i.e., sewer, storm lines) are proposed in areas deeper than five feet below
existing grade.
I Fill materials placed during mass grading operations generally consist of silty sands, and mixtures of
angular gravel and boulders generated from blasting operations in granitic rock. Soils consisting of
I sandy clays were placed in deeper fill areas. Based on information presented in Reference No. 2, the
fill is compacted to at least 90 percent of the laboratory maximum dry density at or slightly above the
I optimum moisture content in accordance with ASTM D 1557. Excluding the upper approximately
one foot, the compacted fill is suitable for support of additional fill and/or structural loading. The
I
upper one foot will require processing as part of further development.
4.2 Granitic Rock (Kgr)
I Cretaceous-age, granitic basement rock of the Southern California Batholith underlies the compacted
fill and is exposed at finish sheet-grade at the north end of the lot and slope areas. Undercutting of
I granitic rock was not performed during mass grading. Based upon our observations during previous
mass grading, and recent exploratory trench excavations, the rock materials are highly weathered in
the upper 3 to 6 feet. Proposed excavations below that depth may encounter fresh, extremely strong
I hard rock that may require blasting to excavate for deeper excavations. The granitic unit exhibits
adequate bearing and slope stability characteristics.
The soils derived from excavations within the decomposed granitic rock are expected to consist of
very low to low expansive (Expansion Index [El] < 50), silty, medium- to coarse-grained sands. It
Project No. 06442-32-27 -3- June 24, 2016
I
I
I should be anticipated that excavations within the bedrock may generate boulders and oversize
materials (rocks >12 inches) that will require special handling and placement as recommended
I hereinafter. Oversize rock fragments may also require exportation from the site since the available fill
volume is limited.
1 5. RIPPABILITY AND ROCK CONSIDERATIONS
We performed a subsurface exploration program that consisted of excavating exploratory trenches
I across the sheet-graded pad to evaluate the granitic rock exposed at grade with respect to weathering.
We performed the trenching with a John Deere 410G rubber tire backhoe with a 2-foot-wide bucket.
I We used the information obtained from the field study to base an opinion regarding the rippability
characteristics of the bedrock. Rock rippability is a function of natural weathering processes that can
vary vertically and horizontally over short distances depending on jointing, fracturing, and/or
I mineralogic discontinuities within the bedrock.
I Based on the exploratory trenching performed, it is expected that the proposed excavations into
bedrock will encounter rippable to marginally-rippable granitic rock to at least the depths shown on
the trench logs utilizing conventional heavy duty grading and trenching equipment. The exploratory I trench logs are presented in Appendix A, Figures A-1 through A-6. Excavations that extend greater
than the depths shown on the trench logs may encounter difficult ripping conditions and may require
I rock breaking or blasting techniques. Excavations can also be expected to generate oversized rock
(rocks >12 inches), which will necessitate typical hard rock handling and placement procedures during
grading operations. Proposed cuts in the weathered mantle may also generate oversized fragments.
Earthwork construction should be carefully planned to efficiently utilize available rock placement
I areas, if present. Oversize materials should be placed in accordance with rock placement procedures
presented in Appendix D of this report and governing jurisdictions.
1 6. GROUNDWATER
I Groundwater was not observed during mass grading operations for Lot 4 or during the recent field
study. Groundwater is not anticipated to impact proposed project development, however, perched
water conditions may develop following periods of heavy precipitation or prolonged irrigation. In the I event that surface seeps develop, shallow subdrains may be necessary to collect and convey the
seepage to a suitable outlet facility.
I
I
Project No. 06442-32-27 -4- June 24, 2016
7. GEOLOGIC HAZARDS
7.1 Faulting
Based on field observations made during previous grading operations, review of published geologic
maps, and previous geotechnical reports; the subject lot is not located on any known active,
potentially active, or inactive fault traces as defined by the California Geological Survey (CGS).
7.2 Seismicity-Deterministic Analysis
We used the computer program EZ-FRISK (Version 7.65) to determine the distance of known faults
to the site and to estimate ground accelerations at the site for the maximum anticipated seismic event.
According to the results of the computer program EZ-FRISK (Version 7.65), 10 known active faults
are located within a search radius of 50 miles from the property. We used acceleration attenuation
relationships developed by Boore-Atkinson (2008) NGA U5G52008, Campbell-Bozorgnia (2008)
NGA USGS, and Chiou-Youngs (2008) NGA in our analysis. The nearest known active faults are the
Newport-Inglewood and Rose Canyon Fault Zone, located approximately eight miles west of the lot
and are the dominant sources of potential ground motion. Table 7.2 lists the estimated maximum
earthquake magnitudes and PGA's for the most dominant faults for the site location calculated for
Site Class D as defined by Table 1613.3.2 of the 2013 California Building Code (CBC).
TABLE 7.2
DETERMINISTIC SPECTRA SITE PARAMETERS
Fault Name
Distance
from Site
(miles)
Maximum
Earthquake
Magnitude
(MW)
Peak Ground Acceleration
Boore-
Atkinson
2008 (g)
Campbell-
Bozorgnia
2008 (g)
Chiou-
Youngs
2007 (g)
Newport-Inglewood/Rose Canyon 8 7.5 0.29 0.24 0.32
Rose Canyon 8 6.9 0.24 0.23 0.25
Elsinore 20 7.85 0.21 0.15 0.19
Coronado Bank 24 7.4 0.16 0.11 0.13
Palos Verdes Connected 24 7.7 0.18 0.12 0.16
Earthquake Valley 39 6.8 0.08 0.06 0.05
Palos Verdes 40 7.3 0.10 0.07 0.07
San Joaquin Hills 40 7.1 0.09 0.09 0.08
San Jacinto 45 7.88 0.12 0.08 0.10
Chino 1 50 1 6.8 1 0.06 1 0.05 1 0.04
I
I
I
Project No. 06442-32-27 -5 - June 24, 2016
I
I
I
I
I
F1
I
I
I
I
I
I
I
[1
Li
I
7.3 Seismicity-Probabilistic Analysis
We used the computer program EZ-FRISK (version 7.65) to perform a probablilistic seismic hazard
analysis. EZ-FRISK operates under the assumption that the occurrence rate of earthquakes on each
mapped Quaternary fault is proportional to the fault slip rate. The program accounts for earthquake
magnitude as a function of rupture length. 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) rupture length for a given magnitude,
(3) location of the rupture 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 2008,
Campbell-Bozorgnia (2008) NGA USGS 2008, and Chiou-Youngs (2008) NGA USGS 2008 in the
analysis. Table 7.3 presents the site-specific probabilistic seismic hazard parameters including
acceleration-attenuation relationships and the probability of exceedence for Site Class D.
TABLE 7.3
PROBABILISTIC SEISMIC HAZARD PARAMETERS
Probability of Exceedence
Peak Ground Acceleration
Boore-Atkinson,
2008 (g)
Campbell-Bozorgnia,
2008 (g)
Chiou-Youngs,
2008 (g)
2% in a 50 Year Period 0.47 0.41 0.48
5% in a 50 Year Period 0.35 0.31 0.35
10% in a 50 Year Period 0.27 0.24 0.26
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 frequency and duration of
motion and soil conditions underlying the site. Seismic design of the structures should be evaluated in
accordance with the California Building Code (CBC) or City of Carlsbad guidelines.
7.4 Landslides
No landslides were encountered within the site or mapped within the immediate areas influencing the
project development. The risk associated with landslide hazard is very low.
I
I
I
Project No. 06442-32-27 - 6 - June 24, 2016
Li
I
I
I
I
I
I
U
I
I
I
1
I
I
[1
H
I
1 7.5 Liquefaction
I
I
I
The risk associated with liquefaction and seismically induced settlement hazard at the subject project
is very low due to the existing dense compacted fill and very dense nature of the granitic bedrock,
construction of canyon subdrains, and the lack of a permanent, shallow groundwater table.
7.6 Tsunamis and Seiches
The risk associated with tsunamis and seiches hazard at the project is very low due to the large distance
from the coastline and the absence of an upstream body of water.
I
I
Li
I
I
I
I
I
I
I
I
I
Project No. 06442-32-27 -7- June 24, 2016
I
1 8. CONCLUSIONS AND RECOMMENDATIONS
8.1 General
I 8.1.1 No soil or geologic conditions were encountered during this study that would preclude the
development of the property as presently planned provided the recommendations of this
I report are followed.
I 8.1.2 Lot 5 is comprised of compacted fill and granitic rock. The compacted fill and bedrock are
suitable for support of additional fill or structural loads. In areas where fill is required to
achieve ultimate grade, or proposed excavations into existing fill are less than one foot, the
I upper one foot of compacted fill should be scarified, moisture conditioned, and compacted
prior to placing fill.
8.1.3 Depending on the time of year that fine grading is performed, wet to saturated soil
conditions may be encountered, especially in the temporary detention basin. Wet soils, if I encountered, will need to be dried or mixed with dryer soil to facilitate proper compaction.
1 8.1.4 Planned fine grading will result with a cut to fill transition condition across the footprint of
the proposed building. The cut portion (bedrock) should be undercut and replaced with
I compacted fill to reduce the potential for differential settlement of the structure. The
undercut should be performed in accordance with Section 8.4.9.
I 8.1.5 Future grading and construction of utilities and foundations will likely encounter and
generate some rock fragments greater than six inches. Excavations for improvements in fill
I areas that extend through the 3-foot-thick soil cap or into the granitic rock, such as sewer
lines, may also encounter hard granitic rock and rock fragments greater than 12 inches.
Excavation difficulties should be anticipated.
I 8.1.6 Possible blasting or rock breaking may be required for excavations that extend into fresh or
I less weathered granitic bedrock. Core stones or oversize material may also be generated
that will require special handling and fill placement procedures. The potential for these
conditions should be taken into consideration when determining the type of equipment to I utilize for future excavation operations. Due to the absence of areas of available fill
volume, it is unlikely that the oversize material could be placed as compacted fill during
I the grading operation; hence, the oversize material may need to be exported.
I 8.1.7 It is not uncommon for groundwater or seepage conditions to develop where none
previously existed, particularly after landscape irrigation is initiated or following
precipitation. The occurrence of induced groundwater seepage from landscaping can be
I
I
Project No. 06442-32-27 - 8 - June 24 2016
I
I greatly reduced by implementing and monitoring a landscape program that limits irrigation
to that sufficient to support the vegetative cover without over watering. Shallow subdrains
I may be required in the future if seeps occur after rainy periods or after landscaping is
installed.
8.2 Soil Characteristics
8.2.1 Laboratory testing performed on soil samples collected during the mass grading operations
I indicate that the prevailing soils within approximately three feet of grade have an Expansion
Index (El) less than 20 and are defined as "non-expansive" by 2013 California Building Code
I
I
I
I
I
I
I
8.2.2
I
I
I
H
(CBC) Section 1803.5.3. Pertinent laboratory test results performed during previous mass
grading operations are presented in Appendix B, Table III. Table 8.2.1 presents soil
classifications based on the El per ASTM D 4829. We expect the majority of the on-site soils
possess a very low expansion potential. Geocon Incorporated will perform additional
expansion index testing after completion of fine grading operations to evaluate the expansion
potential of material present within the upper approximately three feet of ultimate design
finish elevation.
TABLE 8.2.1
SOIL CLASSIFICATION BASED ON EXPANSION INDEX
ASTM D 4829
Expansion Index (El) Soil Classification
0-20 Very Low
21-50 Low
51 -90 Medium
91-130 High
Greater Than 130 Very High
Laboratory testing on soil samples collected during mass grading were also tested to
evaluate water-soluble sulfate content. Table IV, Appendix B summarizes the laboratory
test results. Based on the test results, the on-site soils at the locations tested possess a "Not
Applicable" ("SO") sulfate exposure to concrete structures as defined by 2013 CBC
Section 1904 and ACT 318 Sections 4.2 and 4.3. We recommend that guidelines presented
in the CBC and ACT be followed in determining the type of concrete to be used.
Table 8.2.2 presents a summary of concrete requirements set forth by the CBC and ACT.
The presence of water-soluble sulfates is not a visually discernible characteristic; therefore,
other soil samples from the site could yield different concentrations. Additionally, over
time landscaping activities (i.e., addition of fertilizers and other soil nutrients) may affect
the concentration. Based on the discussion above and during fine grading operations,
I
Project No. 06442-32-27 -9- June 24, 2016
additional soil sampling and testing should be performed on fill soils located near finish
pad grade to evaluate water-soluble sulfate content.
TABLE 8.2.2
REQUIREMENTS FOR CONCRETE EXPOSED TO SULFATE-CONTAINING SOLUTIONS
Water-Soluble Maximum Minimum Sulfate Exposure Sulfate Cement Water to Compressive Exposure Class Percent Type Cement Ratio Strength (psi) by Weight by Weight
Negligible SO 0.00-0.10 -- -- 2,500
Moderate Si 0.10-0.20 II 0.50 4,000
Severe S2 0.20-2.00 V 0.45 4,500
Very Severe S3 >2.00 V+Pozzolan
or 0.45 4,500 Slag
8.2.3 Geocon Incorporated does not practice in the field of corrosion engineering. If
improvements that could be susceptible to corrosion are planned, it is recommended that
further evaluation by a corrosion engineer be performed.
8.3 Subdrains
8.3.1 No new subdrains are expected considering the limited fill depth that is planned for fine
grading operations. The existing subdrain should be protected if underground utilities are
planned in that area. Any conflicts with proposed improvements should be brought to the
attention of Geocon for further recommendations.
1 8.4 Grading
1 8.4.1 All grading should be performed in accordance with the Recommended Grading
Specifications contained in Appendix D. Where the recommendations of Appendix D
I conflict with this section of the report, the recommendations of this section take
precedence.
1 8.4.2 Prior to commencing grading, a preconstruction conference should be held at the site with
the owner or developer, grading contractor, civil engineer, and geotechnical engineer in
I attendance. Special soil handling and the fine grading plan can be discussed at that time.
I 8.4.3 Grading should be performed in conjunction with the observation and compaction testing
services of soil should observed on a Geocon Incorporated. Fill be full-time basis during
placement and, tested to check in-place dry density and moisture content.
I
Project No. 06442-32-27 _10 - June 24, 2016
I
I
I
I
I
I
I
I
1
I
I
8.4.4
Site preparation should begin with the removal of all deleterious material and vegetation in
areas of proposed grading. The depth of removal should be such that soil 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.
8.4.5 Loose or soft accumulated soils in the temporary detention basin will need to be removed
and compacted prior to filling the basin. Abandoned storm drain pipes associated with the
I temporary basin should be removed and the resulting excavation backfilled in accordance
with the recommendations presented herein.
1 8.4.6 Areas to receive fill, and where practical for areas consisting of bedrock, should be
scarified to a depth of at least 12 inches, moisture conditioned as necessary, and compacted
I to at least 90 percent relative compaction prior to placing additional fill. In areas where
proposed cuts into existing fills are less than 12 inches, the resulting finish-grade soils
should be scarified, moisture conditioned as necessary, and compacted to a minimum dry I density of 90 percent of the laboratory maximum dry density. Near-surface soils may need
to be processed to greater depths depending on the amount of drying or wetting that has
I occurred within the soils since the initial sheet grading of the pad. The actual extent of
remedial grading should be determined in the field by the geotechnical engineer or ' engineering geologist. Overly wet surficial soils, if encountered, will need to be removed to
expose existing dense, moist compacted fill or granitic rock. The wet soils will require
I drying and/or mixing with drier soils to facilitate proper compaction.
8.4.7 After site preparation and removal of unsuitable soils as described above is performed, the
I site should then be brought to final subgrade elevations with structural fill compacted in
layers. In general, soils native to the site are suitable for re-use as fill provided vegetation,
debris and other deleterious matter are removed. Layers of fill should be no thicker than
1 will allow for adequate bonding and compaction. Fill, including backfill and scarified
ground surfaces, should be compacted to at least 90 percent of laboratory maximum dry
I density as determined by ASTM D 1557, at or slightly above optimum moisture content.
The project geotechnical engineer may consider fill materials below the recommended
minimum moisture content unacceptable and may require additional moisture conditioning I prior to placing additional fill.
I 8.4.8 Based on existing as-graded condition of the pad portion of the lot and proposed grading
presented on the site plan, fine grading will result in a cut to fill transition condition within
- the building footprint. Consequently, the foundation elements may be bearing on
compacted fill and bedrock resulting in potentially unacceptable differential settlements.
I
Project No. 06442-32-27 -11- June 24, 2016 I
I
To reduce the potential for differential settlement, the cut portion (granitic bedrock) of
cut/fill transition or where bedrock is located within four feet of design pad grade, should
be over-excavated (undercut) a minimum of four feet below finish pad grade or at least
two foot below the lowest foundation element, whichever is deeper, and replaced with
compacted low expansive (Expansion Index [El] <50) soil fill predominately consisting of
6-inch-minus rock. The undercutting will also facilitate excavation of proposed shallow
utilities beneath the building. The undercut should extend at least five feet horizontally
outside the limits of the building footprint area and isolated spread footings located outside
the building limits. Overexcavations should be cut at a positive gradient toward the parking
lot or toward the deepest fill area to provide drainage for moisture migration along the
contact between the bedrock and compacted fill.
1 8.4.9
1
I
I
LI
8.4.10 For exterior utilities (i.e., storm drain, sewer, dry utilities, water) that will be located in
areas of exposed granitic rock at pad grade following planned grading, consideration
should be given to performing exploratory excavations to evaluate the rippability
characteristics of the bedrock. This work should be performed during grading operations.
The need to undercut the underlying granitic rock within the utility corridors should be
determined in the field based on the findings of the exploratory trenching. The undercuts, if
needed, should extend at least one foot below the deepest utility. Undercuts performed
should be replaced with soil fill predominately consisting of 6-inch-minus rock fragments.
8.4.11 For areas to receive fill, rock fragments greater than 6 inches in maximum dimension
should not be placed within four feet of finish grade in the building pad area and three feet
of subgrade in driveways/parking areas. Rock fragments greater than 12 inches in
maximum dimension should not be placed within the upper 10 feet of finish grade.
8.4.12 It is recommended that excavations be observed during grading by a representative of
Geocon Incorporated to check that soil and geologic conditions do not differ significantly
from those anticipated.
8.4.13 It is the responsibility of the contractor to ensure that all excavations and trenches are
properly shored and maintained in accordance with applicable OSHA rules and regulations
in order to maintain safety and maintain the stability of adjacent existing improvements.
8.4.14 Imported soils (if required), should consist of granular very low to low expansive soils
(El < 50). Prior to importing the soil, samples from proposed borrow areas should be
obtained and subjected to laboratory testing to check if the material conforms to the
recommended criteria. The import soil should be free of rock greater than six inches and
construction debris. Laboratory testing typically takes up to four days to complete. The
I
Project No. 06442-32-27 -12- June 24, 2016
I
I
I
I
I
I
[I
I
I
I
I grading contractor needs to coordinate the laboratory testing into the schedule to provide
sufficient time to allow for completion of testing prior to importing materials.
1 8.5 Slopes
I 8.5.1 Slope stability analyses were previously performed on the 2:1 slopes on the property for the
overall Carlsbad Oaks North Business Park development (see the referenced geotechnical
reports). The deep-seated and surficial slope stability analyses where performed using the
I simplified Janbu analysis utilizing average drained direct shear strength parameters based
on laboratory tests performed during our investigation. The results of the analysis indicate
I that cut and fill slopes have a factor-of-safety of at least 1.5 against deep seated and
surficial instability for the project slopes.
8.5.2 No new significant fill slopes are planned during this phase of grading.
I 8.5.3 All slopes should be landscaped with drought-tolerant vegetation having variable root
depths and requiring minimal landscape irrigation. In addition, all slopes should be drained
I and properly maintained to reduce erosion. Slope planting should generally consist of
drought tolerant plants having a variable root depth. Slope watering should be kept to a
minimum to just support the plant growth.
8.6 Seismic Design Criteria
1 8.6.1 We used the computer program US. Seismic Design Maps, provided by the USGS.
Table 8.6.1 summarizes site-specific design criteria obtained from the 2013 California
I Building Code (CBC; Based on the 2012 International Building Code [IBC] and ASCE 7-10),
Chapter 16 Structural Design, Section 1613 Earthquake Loads. The short spectral response
uses a period of 0.2 seconds. The values presented in Table 8.6.1 are for the risk-targeted
I maximum considered earthquake (MCER). Based on soil conditions and planned grading, the
building should be designed using a Site Class D. We evaluated the Site Class based on the
discussion in Section 1613.3.2 of the 2013 CBC and Table 20.3-1 of ASCE 7-10.
I
I
I
d
I
Project No. 06442-32-27 - 13 - June 24, 2016
TABLE 8.6.1
2013 CBC SEISMIC DESIGN PARAMETERS
Parameter Value 2013 CBC Reference
Site Class D Section 1613.3.2
NICER Ground Motion Spectral l.037g Figure 1613.3.1(1) Response Acceleration - Class B (short), Ss
NICER Ground Motion Spectral 0.403g Figure 1613.3.1(2) Response Acceleration — Class B (1 sec), i
Site Coefficient, FA 1.085 Table 1613.3.3(1)
Site Coefficient, Fv 1.597 Table 16 13.3.3(2)
Site Class Modified NICER Spectral 1.125g Section 1613.3.3 (Eqn 16-37) Response Acceleration (short), SMS
Site Class Modified NICER Spectral 0.643g Section 16 13.3.3 (Eqn 16-38) Response Acceleration (1 sec), SM!
5% Damped Design Spectral
Response Acceleration (short), SDS 0.750g Section 1613.3.4 (Eqn 16-39)
5% Damped Design Spectral 0.429g Section 1613.3.4 (Eqn 16-40) Response Acceleration (1 sec), SD!
8.6.2 Table 8.6.2 presents additional seismic design parameters for projects located in Seismic
Design Categories of D through F in accordance with ASCE 7-10 for the mapped
maximum considered geometric mean (MCEG).
TABLE 8.6.2
2013 CBC SITE ACCELERATION PARAMETERS
Parameter Value, Site Class D ASCE 7-10 Reference
Mapped MCEG Peak Ground 0.394g Figure 22-7 Acceleration, PGA
Site Coefficient, FPGA 1.106 Table 11.8-1
Site Class Modified MCEG
Peak Ground Acceleration, PGAM 0.436g Section 11.8.3 (Eqn 11.8-1)
8.6.3 Conformance to the criteria for seismic design does not constitute any guarantee or
assurance that significant structural damage or ground failure will not occur in the event of
a maximum level earthquake. The primary goal of seismic design is to protect life and not
to avoid all damage, since such design may be economically prohibitive.
I
I
Project No. 06442-32-27 - 14 - June 24, 2016
I]
I
1
1
I
I
1 8.7 Foundation and Concrete Slab-On-Grade Recommendations
8.7.1 The project is suitable for the use of continuous strip footings, isolated spread footings, or
I appropriate combinations thereof, provided the preceding grading recommendations are
followed.
8.7.2 The following recommendations are for the planned structure and assume that the grading
will be performed as recommended in this report. Continuous footings should be at least
1 12 inches wide and should extend at least 24 inches below lowest adjacent pad grade and
be founded on properly compacted fill. Isolated spread footings should be at least two feet
I square, extend a minimum of 24 inches below lowest adjacent pad grade, and be founded
on properly compacted fill. A typical footing dimension detail is presented on Figure 4.
1 8.7.3 The use of isolated footings, which are located beyond the perimeter of the building and
support structural elements connected to the building, are not recommended. Where this
I condition cannot be avoided, isolated footings should be connected to the building
foundation system with grade beams.
1 8.7.4 The project structural engineer should design the reinforcement for the footings. For
continuous footings, however, we recommend minimum reinforcement consisting of four
I No. 5 steel reinforcing bars, two placed near the top of the footing and two placed near the
bottom. The project structural engineer should design reinforcement of isolated spread
I footings.
8.7.5 The recommended allowable bearing capacity for foundations designed as recommended
I above is 2,500 pounds per square foot (psf) for foundations in properly compacted fill soil.
This soil bearing pressure may be increased by 300 psf and 500 psf for each additional foot
I of foundation width and depth, respectively, up to a maximum allowable soil bearing of
4,000 psf.
1 8.7.6 The allowable bearing pressures recommended above are for dead plus live loads only and
may be increased by up to one-third when considering transient loads such as those due to
wind or seismic forces.
I 8.7.7 The estimated maximum total and differential settlement for the planned structure due to
foundation loads is 1 inch and 3/4 inch, respectively over a span of 40 feet.
1 8.7.8 Building interior concrete slabs-on-grade should be at least five inches in thickness. Slab
reinforcement should consist of No. 3 steel reinforcing bars spaced 18 inches on center in
I
Project No. 06442-32-27 -15- June 24, 2016
[1
I both directions placed at the middle of the slab. If the slabs will be subjected to heavy
loads, consideration should be given to increasing the slab thickness and reinforcement.
The project structural engineer should design interior concrete slabs-on-grade that will be I subjected to heavy loading (i.e., fork lift, heavy storage areas). Subgrade soils supporting
heavy loaded slabs should be compacted to at least 95 percent relative compaction.
8.7.9 A vapor retarder should underlie slabs that may receive moisture-sensitive floor coverings
I or may be used to store moisture-sensitive materials. The vapor retarder design should be
consistent with the guidelines presented in the American Concrete Institute's (ACT) Guide
for Concrete Slabs that Receive Moisture-Sensitive Flooring Materials (ACT 302.2R-06). I In addition, the membrane should be installed in a manner that prevents puncture in
accordance with manufacturer's recommendations and ASTM requirements. The project
I architect or developer should specify the type of vapor retarder used based on the type of
floor covering that will be installed and if the structure will possess a humidity controlled
environment.
I
8.7.10 The project foundation engineer, architect, and/or developer should determine the thickness
I of bedding sand below the slab. Typically, 3 to 4 inches of sand bedding is used in the San
Diego County area. Geocon should be contacted to provide recommendations if the
bedding sand is thicker than 6 inches.
8.7.11 Exterior slabs not subject to vehicle loads should be at least 4 inches thick and reinforced
I with 6x6-W2.9/W2.9 (6x6-6/6) welded wire mesh or No. 3 reinforcing bars spaced at
24 inches on center in both directions to reduce the potential for cracking. The mesh should
I be placed in the middle of the slab. Proper mesh positioning is critical to future
performance of the slabs. The contractor should take extra measures to provide proper
mesh placement. Prior to construction of slabs, the subgrade should be moisture
I conditioned to at least optimum moisture content and compacted to a dry density of at least
90 percent of the laboratory maximum dry density in accordance with ASTM 1557.
8.7.12 To control the location and spread of concrete shrinkage and/or expansion cracks, it is
- recommended that crack-control joints be included in the design of concrete slabs. Crack-
control joint spacing should not exceed, in feet, twice the recommended slab thickness in
inches (e.g., 10 feet by 10 feet for a 5-inch-thick slab). Crack-control joints should be
I created while the concrete is still fresh using a grooving tool or shortly thereafter using saw
cuts. The structural engineer should take criteria of the American Concrete Institute into
consideration when establishing crack-control spacing patterns.
I
Project No. 06442-32-27 -16- June 24, 2016
I
I
1 8.7.13 The above foundation and slab-on-grade dimensions and minimum reinforcement
recommendations are based upon soil conditions only, and are not intended to be used in
I
lieu of those required for structural purposes. The project structural engineer should design
actual concrete reinforcement.
1 8.7.14 No special subgrade presaturation is deemed necessary prior to placement of concrete.
However, the slab and foundation subgrade should be moisture conditioned as necessary to
maintain a moist condition as would be expected in any concrete placement.
8.7.15 The recommendations of this report are intended to reduce the potential for cracking of
I slabs due to expansive soil (if present), differential settlement of existing soil or soil with
varying thicknesses. However, even with the incorporation of the recommendations
I presented herein, foundations, stucco walls, and slabs-on-grade placed on such conditions
may still exhibit some cracking due to soil movement and/or shrinkage. The occurrence of
I concrete shrinkage cracks is independent of the supporting soil characteristics. Their
occurrence may be reduced and/or controlled by limiting the slump of the concrete, proper
concrete placement and curing, and by the placement of crack control joints at periodic
I intervals, in particular, where re-entrant slab corners occur.
' 8.7.16 A representative of Geocon Incorporated should observe the foundation excavations prior
to the placement of reinforcing steel or concrete to check that the exposed soil conditions
are consistent with those anticipated. If unanticipated soil conditions are encountered,
I foundation modifications may be required.
I 8.7.17 Geocon Incorporated should be consulted to provide additional design parameters as
required by the structural engineer.
1 8.8 Retaining Walls and Lateral Loads Recommendations
I 8.8.1 Retaining walls not restrained at the top and having a level backfill surface should be
designed for an active soil pressure equivalent to the pressure exerted by a fluid with a
density of 35 pounds per cubic foot (pcf). Where the backfill will be inclined at 2:1
I (horizontal:vertical), an active soil pressure of 50 pcf is recommended. These soil pressures
assume that the backfill materials within an area bounded by the wall and a 1:1 plane
extending upward from the base of the wall possess an Expansion Index 50. Geocon
I Incorporated should be consulted for additional recommendations if backfill materials have
an El >50.
I
I
Project No. 06442-32-27 -17- June 24, 2016
I
8.8.2 Where walls are restrained from movement at the top, an additional uniform pressure of
8H psf (where H equals the height of the retaining wall portion of the wall in feet) should
be added to the active soil pressure where the wall possesses a height of 8 feet or less and
12H where the wall is greater than 8 feet. For retaining walls subject to vehicular loads
within a horizontal distance equal to two-thirds the wall height, a surcharge equivalent to
two feet of fill soil should be added (total unit weight of soil should be taken as 130 pcf).
8.8.3 Soil contemplated for use as retaining wall backfill, including import materials, should be
identified in the field prior to backfill. At that time Geocon Incorporated should obtain
samples for laboratory testing to evaluate its suitability. Modified lateral earth pressures
may be necessary if the backfill soil does not meet the required expansion index or shear
strength. City or regional standard wall designs, if used, are based on a specific active
lateral earth pressure and/or soil friction angle. In this regard, on-site soil to be used as
backfill may or may not meet the values for standard wall designs. Geocon Incorporated
should be consulted to assess the suitability of the on-site soil for use as wall backfill if
standard wall designs will be used.
8.8.4 Unrestrained walls will move laterally when backfilled and loading is applied. The amount
of lateral deflection is dependent on the wall height, the type of soil used for backfill, and
loads acting on the wall. The wall designer should provide appropriate lateral deflection
quantities for planned retaining walls structures, if applicable. These lateral values should
be considered when planning types of improvements above retaining wall structures.
8.8.5 Retaining walls should be provided with a drainage system adequate to prevent the buildup
of hydrostatic forces and should be waterproofed as required by the project architect. The
use of drainage openings through the base of the wall (weep holes) is not recommended
where the seepage could be a nuisance or otherwise adversely affect the property adjacent
to the base of the wall. The above recommendations assume a properly compacted granular
(El <50) free-draining backfill material with no hydrostatic forces or imposed surcharge
load. A typical retaining wall drainage detail is presented on Figure 5. If conditions
different than those described are expected, or if specific drainage details are desired,
Geocon Incorporated should be contacted for additional recommendations.
8.8.6 In general, wall foundations having a minimum depth and width of one foot may be
designed for an allowable soil bearing pressure of 2,500 psf, provided the soil within three
feet below the base of the wall has an Expansion Index < 90. The recommended allowable
soil bearing pressure may be increased by 300 psf and 500 psf for each additional foot of
foundation width and depth, respectively, up to a maximum allowable soil bearing pressure
of 4,000 psf.
I
Project No. 06442-32-27 - 18 - June 24, 2016
1
I
I
I
I
'I
I
I
I
i
I
I
I
I
I
I
1 8.8.7 The proximity of the foundation to the top of a slope steeper than 3:1 could impact the
allowable soil bearing pressure. Therefore, Geocon Incorporated should be consulted where
I such a condition is anticipated. As a minimum, wall footings should be deepened such that
-
the bottom outside edge of the footing is at least seven feet from the face of slope when
I
located adjacent and/or at the top of descending slopes.
8.8.8 The structural engineer should determine the seismic design category for the project in
I accordance with Section 1613 of the CBC. If the project possesses a seismic design
category of D, E, or F, retaining walls that support more than 6 feet of backfill should be
designed with seismic lateral pressure in accordance with Section 18.3.5.12 of the 2013
I CBC. 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
I base of the wall and zero at the top of the wall. A seismic load of 21 H should be used for
design. We used the peak ground acceleration adjusted for Site Class effects, PGAM,
of 0.434g calculated from ASCE 7-10 Section 11.8.3 and applied a pseudo-static I coefficient of 0.33.
I 8.8.9 For resistance to lateral loads, a passive earth pressure equivalent to a fluid density of
300 pcf is recommended for footings or shear keys poured neat against properly compacted
granular fill soils or undisturbed formation materials. The passive pressure assumes a
horizontal surface extending away from the base of the wall at least five feet or three times
the surface generating the passive pressure, whichever is greater. The upper 12 inches of
I material not protected by floor slabs or pavement should not be included in the design for
lateral resistance. Where walls are planned adjacent to and/or on descending slopes, a
passive pressure of 150 pcf should be used in design.
8.8.10 An ultimate friction coefficient of 0.40 may be used for resistance to sliding between soil
I and concrete. This friction coefficient may be combined with the passive earth pressure
when determining resistance to lateral loads.
8.8.11 The recommendations presented above are generally applicable to the design of rigid
concrete or masonry retaining walls having a maximum height of 12 feet. In the event that
I walls higher than 12 feet are planned, Geocon Incorporated should be consulted for
additional recommendations.
- 8.9 Mechanically Stabilized Earth (MSE) Retaining Walls
1 8.9.1 We are providing geotechnical parameters for mechanically stabilized earth (MSE)
reinforced retaining walls that are being considered for the project. Geogrid retaining walls
I
Project No. 06442-32-27 _19- June 24, 206
I
are alternative walls that consist of modular block facing units with geogrid reinforced
earth behind the block. The geogrid attaches to the block units and is typically placed at
specified vertical intervals and embedment lengths. Spacing and lengths are based on the
wall height and type of soil used for backfill.
8.9.2 For design of MSE retaining walls, we recommend an active soil pressure equivalent to the
pressure exerted by a fluid density of 35 pound per cubic foot (pcf) for level backfill.
Where the backfill will be inclined at 2:1 (horizontal:vertical), an active soil pressure of
50 pcf is recommended. Expansive soil should not be used as backfill material behind
retaining walls. Soil placed for retaining wall backfill should have an Expansion Index < 50
and should meet the geotechnical parameters listed in Table 8.9.
TABLE 8.9
GEOTECHNICAL PARAMETERS FOR GEOSYNTHETIC REINFORCED WALLS
Parameter Reinforced Zone Retained Zone Foundation Zone
Angle of Internal Friction 30 degrees 30 degrees 30 degrees
Cohesion 0 psf 0 psf 0 psf
Wet Unit Weight 130 pcf 130 pcf 130 pcf
Notes:
Reinforced Zone is the area where geotextile reinforcing grid is placed.
Retained Zone is the area behind the reinforced zone and within a 1:1 plane extending up and out
from the bottom of the reinforced zone to a horizontal distance equal to the height of the retaining
wall.
Foundation Zone is the area below the reinforced zone and within a 1:1 plane extending down and
out from the bottom of the wall block.
8.9.3 Based on previous laboratory testing, the on-site soils should meet the soil properties listed
in Table 8.9 and soil properties specified by the wall engineer. Laboratory testing should be
performed on samples of the proposed soils to check if the shear strength of the soil meets
the design values and additional soil specifications required by the wall engineer. Results,
if they vary significantly from those in Table 8.9, should be provided to the wall designer
for his review and determination if modifications to the design are warranted. The designer
should re-evaluate stability of the walls based on the shear strength test results.
8.9.4 An allowable soil bearing pressure of 2,500 pounds per square foot (psf) can be used for
foundation design and calculations for wall bearing. This bearing pressure assumes a
minimum foundation width and depth of 12 inches. The allowable soil bearing pressure
may be increased by 300 psf and 500 psf for each additional foot of foundation width and
depth, respectively, up to a maximum allowable soil-bearing pressure of 4,000 psf. The
Project No. 06442-32-27 -20 - June 24, 2016
I
Li
I
I
I
I
I
I
'I
I
I
I
I
I
I
I
I
I foundation bearing zone of the wall can be considered across the reinforced zone of the
wall.
8.9.5 The bearing pressure may be increased by one-third for transient loads due to wind or
seismic forces.
I 8.9.6 Walls that are built on sloping ground surfaces should be at least seven feet horizontally
I from the slope face to the wall. This may require deepening the foundation embedment to
achieve the seven foot distance.
1 8.9.7 Soil placed within the reinforced zone of the wall should be compacted to at least 90
percent of the laboratory maximum dry density at or slightly above optimum moisture
I content. This is applicable to the entire embedment width of the geogrid reinforcement.
Typically, wall designers specify no heavy compaction equipment within three feet of the
I
face of the wall to reduce the potential for wall deformation during construction. However,
smaller equipment (e.g., walk-behind, self-driven compactors or hand whackers) can be
used to compact the materials without causing deformation of the wall. If the designer
I specifies no compaction effort for this zone, then the uncompacted soil does not meet the
minimum shear strength (angle of internal friction) presented in Table 8.9 and this portion
I
of geogrid should not be relied upon for reinforcement, and overall embedment lengths will
have to be increased to account for the difference.
1 8.9.8 The wall should be provided with a drainage system sufficient enough to prevent excessive
seepage through the wall and water at the base of the wall to prevent hydrostatic pressures
I behind the wall.
8.9.9 Geosynthetic reinforcement must elongate to develop full tensile resistance. This I elongation generally results in movement at the top of the wall. The amount of movement
is dependent upon the height of the wall (e.g., higher walls rotate more) and the type of
I geogrid reinforcing used. In addition, over time geogrid has been known to exhibit creep
(sometimes as much as 5 percent) and can undergo additional movement. Given this
condition, structures and pavement placed within the reinforced and retained zones of the I wall might undergo movement.
1 8.10 Preliminary Pavement Recommendations - Flexible and Rigid
8.10.1 The following preliminary pavement design sections are based on our experience with soil
I conditions within the surrounding area and previous laboratory resistance value (R-Value)
testing performed throughout the Carlsbad Oaks North Business Park development. The
I
Project No. 06442-32-27 -21 - June 24, 2016
I
I
I civil engineer should provide traffic indices (TI) for use in final pavement design. The
preliminary sections presented herein are for budgetary estimating purposes only and are
I not for construction. An R-Value of 35 has been assumed. The final pavement sections will
be provided after the grading operations are completed, subgrade soils are exposed,
laboratory R-Value testing is performed on the subgrade soils and traffic indices are
I provided for our use.
8.10.2 The preliminary pavement section recommendations are for areas that will be used as
passenger vehicle parking and, car/light truck and heavy truck driveways. We evaluated the
flexible pavement sections in accordance with State of California, Department of
Transportation (Caltrans) Highway Design Manual (Topic 633). Rigid pavement sections
consisting of Portland cement concrete (PCC) are based on methods suggested by the
American Concrete Institute Guide for Design and Construction of Concrete Parking Lots
(ACI 330R-08). The structural sections presented herein are in accordance with City of
Carlsbad minimum requirements for private commercial/industrial developments. Table 8.10
summarizes preliminary pavement sections.
TABLE 8.10
PRELIMINARY PAVEMENT DESIGN SECTIONS
Estimated Asphalt Class 2
Aggregate Base PCC
Location Traffic Concrete beneath Asphalt Section
Index [TI]* (inches)** (inches) (inches)Concrete
Automobile Parking 4.5 4.0 4.0 5.0
Automobile! 5.5 4.0 4.0 6.0 Light truck Driveways
Heavy /Trash Truck 6.5 4.0 7.0 7.0
Driveways/Fire Lane
Heavy Truck Loading Apron N/A N/A N/A 7.0
Trash enclosure apron N/A N/A N/A 7•5**
*Civil engineer should provide TI for final pavement design.
**city of Carlsbad minimums for Private Commercial/Industrial developments.
11
I
I
I
I
Project No. 06442-32-27 -22 - June 24, 2016
I
I
Li
I
I
I
I
Lfl
I
I
I
1 8.10.3 We used the following parameters in design of the PCC pavement:
I Modulus of subgrade reaction, k = 200 pci*
Modulus of rupture for concrete, MR = 500 psi'
Traffic Category = A, B, and C
Average daily truck traffic, ADTT = 10 (Cat A) and 25 (Cat B), 700 (Cat C)
I Reinforcing: No. 3 bars placed 24 inches O.C. each way and placed at center of slab.
*pci = pounds per cubic inch.
= pounds per square inch.
I
8.10.4 Asphalt concrete should conform to Section 203-6 of the Standard Specifications for
I Public Works Construction (Greenbook). Class 2 aggregate base should conform to
Section 26-1.02B of Caltrans with a 3%-inch maximum size aggregate.
1 8.10.5 Prior to placing base material and PCC pavement, subgrade soils should be scarified,
moisture conditioned and compacted to a dry density of at least 95 percent of the laboratory
I maximum dry density near or slightly above optimum moisture content in accordance with
ASTM D 1557. The depth of compaction should be at least 12 inches. Base material should
I
be compacted to a dry density of at least 95 percent of the laboratory maximum dry density
near or slightly above optimum moisture content. Asphalt concrete should be compacted to
I
at least 95 percent of the laboratory Hveem density in accordance with ASTM D 2726.
8.10.6 Loading aprons such as trash bin enclosures and heavy truck areas should utilize Portland
I cement concrete as presented in Table 8.10 above. The concrete loading area should extend
out such that both the front and rear wheels of the truck will be located on reinforced
I
concrete pavement when loading and unloading.
8.10.7 The following recommendations are being provided for PCC pavement areas.
A thickened edge or integral curb should be constructed on the outside of concrete
(PCC) slabs subjected to wheel loads. The thickened edge should be 1.2 times the
I slab thickness or a minimum thickness of 2 inches, whichever results in a thicker
edge, at the slab edge and taper back to the recommended slab thickness 3 feet
behind the face of the slab (e.g., a 7-inch-thick slab would have a 9-inch-thick
I edge).
To control the location and spread of concrete shrinkage cracks, crack-control
I joints (weakened plane joints) should be included in the design of the concrete
pavement slab. Crack-control joints should not exceed 30 times the slab thickness
with a maximum spacing of 15 feet (e.g., a 7-inch-thick slab would have a 15-foot
I
Project No. 06442-32-27 -23 - June 24, 2016
I
I
I spacing pattern) and should be sealed with an appropriate sealant to prevent the
migration of water through the control joint to the subgrade materials. The depth of
I
the crack-control joints should be determined by the referenced ACT report.
Construction joints should be provided at the interface between areas of concrete
placed at different times during construction. Doweling is recommended between
I the joints in pavements subjected to heavy truck traffic. Dowels should meet the
recommendations in the referenced ACI guide and should be provided by the
project structural engineer.
8.10.8 The performance of pavement is highly dependent on providing positive surface drainage
I
away from the edge of the pavement. Ponding of water on or adjacent to the pavement will
likely result in pavement distress and subgrade failure. Drainage from landscaped areas
should be directed to controlled drainage structures. Landscape areas adjacent to the edge
I of asphalt pavements are not recommended due to the potential for surface or irrigation
water to infiltrate the underlying permeable aggregate base and cause distress. Where such
I
a condition cannot be avoided, consideration should be given to incorporating measures
that will significantly reduce the potential for subsurface water migration into the aggregate
base. If planter islands are planned, the perimeter curb should extend at least six inches
I below the level of the base materials.
I 8.11 Detention Basin and Bioswales Recommendations
8.11.1 The site is currently underlain by compacted fill or dense granitic bedrock. Planned grading
I will result with additional dense compacted fill and bedrock at grade. As previously
discussed, the compacted fill consists of silty sands, and mixtures of angular gravel and
boulders generated from blasting operations in granitic rock. Soils consisting of sandy
I clays were placed in deeper fill areas. Infiltrating into compacted fill generally results in
settlement and distress to improvements placed over the compacted fill; as well slope
instability. It is our opinion the compacted fill is unsuitable for infiltration of storm water
runoff due to the potential for adverse settlement and slope instability. The granitic bedrock
is also sufficiently dense that infiltration water would be expected to perch on granitic rock.
8.11.2 Any detention basins, bioswales and bio-remediation areas should be designed by the
I 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
I
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
concrete cut-off wall should extend at least 6-inches beyond the perimeter of the gravel-
packed subdrain system.
I
Project No. 06442-32-27 -24 - June 24, 2016
I
I
I 8.11.3 Distress may be caused to planned improvements and properties located hydrologically
downgradient or adjacent to infiltration devices. The distress depends on the amount of
I water to be detained, its residence time, soil permeability, 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
I and slabs, or other impacts as a result of water infiltration. Due to site soil and geologic
conditions, permanent bioswales and bio-remediation areas should be lined with an
I impermeable liner to prevent water infiltration in to the underlying compacted fill.
Temporary detention basins in areas where improvements have not been constructed do not
need to be lined.
I 8.11.4 Appendix C presents the form titled Categorization of Infiltration Feasibility Condition
I (Form 1-8) from the City of Carlsbad BMP Design Manual (February 16, 2016). Criteria 4
and 8 are not related to geotechnical engineering aspects and will need to be addressed by
the civil or groundwater engineer.
8.11.5 The landscape architect should be consulted to provide the appropriate plant
I recommendations. If drought resistant plants are not used, irrigation may be required.
I 8.12 Site Drainage and Moisture Protection
8.12.1 Adequate site drainage is critical to reduce the potential for differential soil movement,
I erosion and subsurface seepage. Under no circumstances should water be allowed to pond
adjacent to footings. The site should be graded and maintained such that surface drainage is
directed away from structures in accordance with 2013 CBC 1804.3 or other applicable
I 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 carry runoff away from the proposed structure.
8.12.2 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
I should provide detailed specifications on the plans for all waterproofing and drainage.
I 8.12.3 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.
I
I
Project No. 06442-32-27 -25 - June 24, 2016
I
I
I 8.13 Slope Maintenance
8.13.1 Slopes that are steeper than 3:1 (horizontal: vertical) may, under conditions that are both
I difficult to prevent and predict, be susceptible to near-surface (surficial) slope instability.
The instability is typically limited to the outer 3 feet of a portion of the slope and usually
I does not directly impact the improvements on the pad areas above or below the slope. The
occurrence of surficial instability is more prevalent on fill slopes and is generally preceded
by a period of heavy rainfall, excessive irrigation, or the migration of subsurface seepage.
I The disturbance and/or loosening of the surficial soils, as might result from root growth,
soil expansion, or excavation for irrigation lines and slope planting, may also be a
I significant contributing factor to surficial instability. It is therefore recommended that, to
the maximum extent practical: (a) disturbed/loosened surficial soils be either removed or
properly recompacted, (b) irrigation systems be periodically inspected and maintained to
I eliminate leaks and excessive irrigation, and (c) surface drains on and adjacent to slopes be
periodically maintained to preclude ponding or erosion. Although the incorporation of the
I above recommendations should reduce the potential for surficial slope instability, it will
not eliminate the possibility and, therefore, it may be necessary to rebuild or repair a
I
portion of the project's slopes in the future.
8.14 Grading, Foundation, and Retaining Wall Plan Review
I 8.14.1 The geotechnical engineer and engineering geologist should review the grading, foundation
and retaining wall plans prior to final City submittal to check their compliance with the
I recommendations of this report and to determine the need for additional comments,
recommendations and/or analysis.
I
I
I
I
I
I
I
Project No. 06442-32-27 - 26 - June 24, 2016
I
LIMITATIONS AND UNIFORMITY OF CONDITIONS
The firm that performed the geotechnical investigation for the project should be retained to
provide testing and observation services during construction to provide continuity of
geotechnical interpretation and to check that the recommendations presented for geotechnical
aspects of site development are incorporated during site grading, construction of
improvements, and excavation of foundations. If another geotechnical firm is selected to
perform the testing and observation services during construction operations, that firm should
prepare a letter indicating their intent to assume the responsibilities of project geotechnical
engineer of record. A copy of the letter should be provided to the regulatory agency for their
records. In addition, that firm should provide revised recommendations concerning the
geotechnical aspects of the proposed development, or a written acknowledgement of their
concurrence with the recommendations presented in our report. They should also perform
additional analyses deemed necessary to assume the role of Geotechnical Engineer of Record.
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 construction,
or if the proposed construction will differ from that anticipated herein, Geocon Incorporated
should be notified so that supplemental recommendations can be given. The evaluation or
identification of the potential presence of hazardous or corrosive materials was not part of the
scope of services provided by Geocon Incorporated.
This report is issued with the understanding that it is the responsibility of the owner, or of his
representative, to ensure that the information and recommendations contained herein are
brought to the attention of the architect and engineer for the project and incorporated into the
plans, and that the necessary steps are taken to see that the contractor and subcontractors
carry out such recommendations in the field.
The findings of this report are valid as of the present date. However, changes in the
conditions of a property can occur with the passage of time, whether they are due to natural
processes or the works of man on this or adjacent properties. In addition, changes in
applicable or appropriate standards may occur, whether they result from legislation or the
broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly
or partially by changes outside our control. Therefore, this report is subject to review and
should not be relied upon after a period of three years.
I
I
Project No. 06442-32-27 June 24, 2016
[I]
I
I
I
I
I
I
I
I
I
I
I
F1
I
I
I
I
r4 ) ____
e
k.E4 ,
' 1
*
—pill
,
41 -fr
THE GEOGRAPH CAL INFORMATION MADE AVAILABLE FOR DISPLAY WAS PROVIDED BY GOGGLE EARTH,
SUBJECT TO AL CENSING AGREEMENT. THE INFORMATION IS FOR ILLUSTRATIVE PURPOSES ONLY; IT IS
NOT INTENDED FOR CLIENTS 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
VICINITY MAP
I
GEOCON
INCORPORATED 1
GEOTECHNICAL. ENVIRONMENTAL. MATERIALS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
RM I AML DSK/GTYPD
CARLSBAD OAKS NORTH
BUSINESS PARK - LOT 5
CARLSBAD, CALIFORNIA
DATE 06-24- 2016 PROJECT NO. 06442-42-27 FIG. 1
P10110106/2712016 9 26AM r By ALVIN LADRILLOND I Rye Locetioe Y /PROJECTS/06442-42-27 /01 51DV1A1LS2644242.27 V, 9yp d.y
r
- - - - - - - - - - - - - - - - - - -
- - - - - - - - - - - - - - - - - - -
KIF
Kg,:
IiL
GEOLOGIC CROSS-SECTION A-A
B B - - - - - - -V Gl.
lhi
I1
GEOLOGIC CROSS-SECTION B-B
Kgr
I
I
I
CONCRETE SLAB
4 0
x - PAD GRADE
SAND AND VAPOR / \ RETARDERIN-' .
ACCORDANCE WITH AC!
. I—Q.
LL 440
L FOOTING'
WIDTH
I
I
I
I
I
I
I
I *SEE REPORT FOR FOUNDATION WIDTH AND DEPTH RECOMMENDATION NO SCALE
I I WALL / COLUMN FOOTING DIMENSION DETAIL I
I
I
GEOCON '5
INCORPORATED
GEOTECHNICAL. ENVIRONMENTAL. MATERIALS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121- 2974
PHONE 858 558-6900 - FAX 858 558-6159
RM I AML DSKIGTYPD
CARLSBAD OAKS NORTH
BUSINESS PARK — LOT 5
CARLSBAD, CALIFORNIA
I DATE 06 -24-2016 I PROJECT NO. 06442 -42-27 I FIG. 4 I
I PIotted06/27/2016 936AM I ByALVlN LADRILLONO I File Location Y:\PROJECTS\06442-42-27 (Lot 5)\DETAILSlWaIb-Column Footing Dimension Detail (COLFOOT2(dwg
I
1
I
I
I
I
I
I
1
I
I
I
I
I
I
1
I
I
I
I
I
I
I
CONCRETE
PROPOSED BROWDITCH
RETAINING WALL
PROPERLY
'N
GROUND SURFACE
BACKFILL -.._.TEMPORARY BACKCUT WATER PROOFING
PER PER OSHA ARCHITECT
2/3 H j -.... MIRAFI 140N FILTER FABRIC
- (OR EQUIVALENT)
-. OPEN GRADED
- - - V MAX. AGGREGATE
GROUND SURFACE
______________ ,I i
1 FOOTING N. 4" DIA. PERFORATED SCHEDULE
I 40 PVC PIPE EXTENDED TO I APPROVED OUTLET
12"
NOTE:
DRAIN SHOULD BE UNIFORMLY SLOPED TO GRAVITY OUTLET
OR TO A SUMP WHERE WATER CAN BE REMOVED BY PUMPING NO SCALE
I TYPICAL RETAINING WALL DRAIN DETAIL I
GEOCON
INCORPORATED 1'
GEOTECHNICAL. ENVIRONMENTAL MATERIALS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121- 2974
PHONE 858 558-6900 - FAX 858 558-6159
RM I AML DSK/GTYPD
Plotted:06I2712016 934AM I ByALVIN LADRILLONO I File LocolionY\PROJECTS\06442.42.27 (Lot 5I0ETAlLSlTyp1coI Retaining Well Drainage Detail (RWDD7A).dwg
CONCRETE
BROWDITCH
RETAINING
WALL
213 H
GROUND SURFACE
WATER PROOFING
- PER ARCHITECT
DRAINAGE PANEL
(MIRADRAIN 6000
OR EQUIVALENT)
12"H
3/4" CRUSHED ROCK
(1 CU.FTIFT.)
FILTER FABRIC
ENVELOPE
MIRAFI 140N OR
JN-
EQUIVALENT
4" DIA. SCHEDULE 40
PERFORATED PVC PIPE
OR TOTAL DRAIN
EXTENDED TO
APPROVED OUTLET
CONCRETE
BROWDITCH
RETAINING -
WALL
213 H
GROUND SURFACE
WATER PROOFING
PER ARCHITECT
DRAINAGE PANEL
(MIRADRAIN 6000
OR EQUIVALENT)
- 4" DIA. SCHEDULE 40
PERFORATED PVC PIPE
OR TOTAL DRAIN
EXTENDED TO
APPROVED OUTLET
PROPOSED
FOOTING
PROPOSED
CARLSBAD OAKS NORTH
BUSINESS PARK - LOT 5
CARLSBAD, CALIFORNIA
DATE 06 - 24 -2016 1 PROJECT NO. 06442 -42 -27 1 FIG. 5
I
I
I
APPENDIX
I
Li
I
I
I
LI
I
I
I
I
I
I
I
I
I
I
I
APPENDIX A
I FIELD INVESTIGATION
I We performed the exploratory trenching on May 31, 2016, which consisted of excavating six backhoe
trenches at the approximate locations shown on Figure 2. The trenches were excavated using a John
I Deere 410G rubber-tire backhoe with a 2-foot-wide bucket to depths ranging from three to nine feet
below existing grade. The trenches were backfihled using on-site soils and the top of trenches were
wheel-rolled for compaction.
Soil encountered in the trenches was visually examined, classified and logged in general conformance
I with ASTM Practice for Description and Identification of Soils (Visual-Manual Procedure D 2488)
and, the granitic rock was classified in general conformance with Caltrans Soil and Rock Logging,
I Classification and Presentation Manual (2010). Logs of the exploratory trenches are presented on
Figures A-I through A-6, in this appendix. The logs depict the various soil types and granitic rock
encountered, and indicate the depths of each trench excavation.
I
I
I
I
I
I
I
I
I
Project No. 06442-32-27 June 24, 2016
I
PROJECT NO. 06442-42-27
TRENCH TI
DEPTH SOIL . L .
SAMPLEIN 0 r) CLASS 99 W
FEET NO. ELEV. (MSL.)346 DATE COMPLETED 05-31-2016 0
EQUIPMENT JD 410G BACKHOE WI 24" BUCKET BY: J. PAGNILLO
MATERIAL DESCRIPTION 0
COMPACTED FILL (Qct)
Medium dense, moist, reddish brown, Silty, fine to coarse SAND with some
::::.. :
clay
-
+ + GRANITIC ROCK (Kgr)
+ Highly weathered, reddish brown, weak GRANITIC ROCK; excavates as silty
+ + fine to coarse sand with rock fragments up to 8 inches
+
++
+ -
++
+
++
- ++ -Becomes moderately weathered and moderately weak -
6
PRACTICAL REFUSAL AT 6 FEET
Groundwater not encountered
Figure A-I, 0644242-27.GPJ
Log of Trench T I, Page 1 of I
SAMPLE SYMBOLS ... SAMPLING UNSUCCESSFUL 11 ... STANDARD PENETRATION TEST U ... DRIVE SAMPLE (UNDISTURBED)
...
DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE ... 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 CONDITIONS AT OTHER LOCATIONS AND TIMES.
I GE000N
I
I
I
I
I
I
I
I
I
I
I
LI
Li
I
PROJECT NO. 0644242-27
TRENCH T2
DEPTH SOIL ~89 2o HL Z
..
CO. z LL
IN
FEET
SAMPLE
NO. CLASS ELEV. (MSL.)345 DATE COMPLETED 0531.2016 w
0 III
z 0 (USCS) U) 9 )- .._ 20
EQUIPMENT JD 410G BACKHOE W/ 24" BUCKET BY: J. PAGNILLO C)
MATERIAL DESCRIPTION 0 -- + + GRANITIC ROCK (Kgr)
+ Highly weathered, yellowish brown, weak GRANITIC ROCK; excavates as
+ + silty, fine to coarse sand with rock fragments up to 8 inches
+
++
+
++
+
++
+ i— 2 - + + -Becomes moderately weathered +
++
+
++
-
++
+
++
+
++ -Difficult digging +
++
+
++
++
+
++
+
6- PRACTICAL REFUSAL AT 6 FEET
Groundwater not encountered
Figure A-2, 06442-42-27.GPJ
Log of Trench T 2, Page 1 of I
SAMPLE SYMBOLS LII ... SAMPLING UNSUCCESSFUL II ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
12 DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE ... 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 CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
I
F
I
I
I
I
I
I
I
I
I
1
Li
I
[1
PROJECT NO. 06442-42-27
TRENCH T3
DEPTH
SAMPLE SOIL
IN
FEET NO. z ELEV. (MSL.)344 DATE COMPLETED 05-31-2016
o EQUIPMENT JD 410G BACKHOE W/ 24" BUCKET BY: J. PAGNILLO
MATERIAL DESCRIPTION
- 0
- ++ - GRANITIC ROCK (Kgr)
+ Moderately weathered, light yellowish brown, moderately strong GRANITIC
+ + ROCK; excavates as silty, fine to coarse sand with rock fragments up to 10
+ inches ++
+
++
+
++
+ -2- ++
+
++
+ -Difficult digging, trench widened
++
+
++
+
++
+
-4- ++
+
++
+
++
+
++
+
++
+
6- PRACTICAL REFUSAL AT 6 FEET
Groundwater not encountered
Figure A-3, 06442-42-27.GPJ
Log of Trench T 3, Page 1 of I
SAMPLE SYMBOLS LII ... SAMPLING UNSUCCESSFUL II ... STANDARD PENETRATION TEST U ... DRIVE SAMPLE (UNDISTURBED)
12 DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE ... 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 CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
I
I
I
1
1
I
I
LI
I
I
I
I
I
I
I
PROJECT NO. 06442-42-27
IX TRENCH
DEPTH SOIL I- zLI Qoi- l)-
IN SAMPLE CLASS _______ H
ZLL
W 0 LU
FEET NO. ELEV. (MSL.)343 DATE COMPLETED 05-31-2016 _____ '-S2LU
0
U5 B uj
>-.... 20 Of CD EQUIPMENT JD 410G BACKHOE WI 24" BUCKET BY: J. PAGNILLO
MATERIAL DESCRIPTION
+ + GRANITIC ROCK (Kgr)
+ Highly weathered, yellowish brown, moderately weak GRANITIC ROCK;
+ + excavates as silty, fine to coarse sand with rock fragments up to 10 inches
+
++
+
++
+
++
+
- 2 + + -Difficult digging - +
++
+
++
REFUSAL AT 3 FEET
Groundwater not encountered
Figure A-4, 06442-42-27.GPJ
Log of Trench T 4, Page 1 of I
SAMPLE SYMBOLS I E ... SAMPLING UNSUCCESSFUL II ... STANDARD PENETRATION TEST U ... DRIVE SAMPLE (UNDISTURBED) I
12 DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE ... WATER TABLE OR SEEPAGE I I 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 CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
I
I
I
I
I
I
I
I
I
I
II
I
I
I
Figure A-5,
Log of Trench T 5, Page 1 of I
06442-42-27.GPJ
I
GEOCON
PROJECT NO. 06442-42-27
I
I
I
1
I
I
I
I
I
I
Ii
I
I
I
TRENCH T5
DEPTH
SAMPLE SOIL I-ZLL << 5
l) ZL L IN
NO. CLASS ELEV. (MSL.)342' DATE COMPLETED 05-31-2016 a— 1— w0 O LLI
FEET
0 Ik_(USCS) u B >- . z
20
EQUIPMENT JD 410G BACKHOE W/ 24" BUCKET BY: J. PAGNILLO W 0 0
MATERIAL DESCRIPTION
+ + GRANITIC ROCK (Kgr)
+ Moderately weathered, yellowish brown, moderately weak GRANITIC
+ + ROCK excavates as silty, fine to coarse sand with rock fragments up to 8 + inches ++
+
++
+
++
2
- + + -Difficult digging; trench widened
+
++
+
++
+
++
+
++
+
. - 4 ____ REFUSAL AT 4 FEET
Groundwater not encountered
SAMPLE SYMBOLS
... SAMPLING UNSUCCESSFUL ... STANDARD PENETRATION TEST U ... DRIVE SAMPLE (UNDISTURBED)
DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE ... 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 CONDITIONS AT OTHER LOCATIONS AND TIMES.
I
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 CONDITIONS AT OTHER LOCATIONS AND TIMES.
SAMPLING UNSUCCESSFUL 11 ... STANDARD PENETRATION TEST U ... DRIVE SAMPLE (UNDISTURBED) SAMPLE SYMBOLS
19 DISTURBED OR BAG SAMPLE ... CHUNK SAMPLE ... WATER TABLE OR SEEPAGE
PROJECT NO. 06442-42-27
TRENCH 6
DEPTH SOIL
IN SAMPLE
NO. 0 CLASS ELEV. (MSL.)342 DATE COMPLETED 05-31-2016 I- FEET
0 (USCS) W (I) iia. >- 0 z
IX EQUIPMENT JD 410G BACKHOE WI 24" BUCKET BY: J. PAGNILLO
MATERIAL DESCRIPTION
0
COMPACTED FILL (Qct)
Medium dense, moist, reddish brown to yellowish brown, Silty, fine to coarse
SAND with trace clay
2
.4.
:.j.:.1:.
6
8
TRENCH TERMINATED AT 9 FEET
Groundwater not encountered
Figure A-6, 06442-42-27.GPJ
Log of Trench T 6, Page 1 of I
I
I
I
I
I
I
I
I
I
I
I
I
LI
I
GE000N
I
I
I
I
I
1
I
APPENDIX
I
I
L
U
I
I
I
r]
I
F-
L
I
I
I
I
I
I
I
I
I
I
I
I
I
I
1
I
I
I
I
I
I
APPENDIX B
LABORATORY TESTING
PERFORMED BY GEOCON INCORPORATED (2006)
FOR
CARLSBAD OAKS NORTH BUSINESS PARK - LOT 5
CARLSBAD, CALIFORNIA
PROJECT NO. 06442-32-27
1
I
I
I
I
I
I
I
I
1
I
I
I
I
I
I
I
I
I
TABLE I
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND
OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM D 1557
Proctor Maximum Optimum
Curve No. Source and Description Dry Density Moisture Content
(pci) (%)
I Dark brown, Silty, fine SAND 129.2 8.5
2 Olive brown, Silty, fine to coarse SAND, 130.1 8.6 with trace gravel
3 Very dark brown, Clayey, fine to medium 128.0 8.9 SAND, with trace gravel
4 Very dark brown, Clayey, fine to medium 123.9 12.0 SAND, with trace gravel
20 Very dark reddish brown, Silty, fine to 133.1 7.6
________
medium SAND
TABLE II
SUMMARY OF LABORATORY DIRECT SHEAR TEST RESULTS
ASSHTO T236
Sample
No.*
Dry Density
(pci)
Moisture Content
(%)
Unit Cohesion
(psi)
Angle of Shear
Resistance (degrees)
20 120.9 6.6 380 39
*Samples were remolded to approximately 90 percent of maximum dry density at near optimum moisture
content.
TABLE III
SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS
ASTM D 4829
Sample No. (Lot No.)
Moisture Content (°") Dry Density
(pci)
Expansion
Index Before Test After Test
El-5 (Lot 5) 8.9 14.8 113.2 0
El-6 (Lot 5) 8.8 14.7 113.2 0
El-7 (Lot 5) 8.8 14.1 113.2 0
Project No. 06442-32-27 MOM June 24, 2016
I
TABLE IV
I SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE TEST RESULTS
CALIFORNIA TEST NO. 417
Sample No. (Lot No.) Water-Soluble Sulfate (%) Sulfate Exposure (Severity)
El-5 (Lot 5) 0.012 Not Applicable
El-6 (Lot 5) 0.017 Not Applicable
El-7 (Lot 5) 0.047 Not Applicable
Li
I
I
I
H
J
I
I
I
I
I
I
I
I
Project No. 06442-32-27 - B-2 - June 24, 2016
1
I
I
I
I
L
I
I
I
I
I
APPENDIX
I
I
I
I
I
I
I
I
I
I
I
Ll
I
ii
I
I
I
I
APPENDIX C
I CITY OF CARLSBAD BMP DESIGN MANUAL -
I CATEGORIZATION OF INFILTRATION FEASIBILITY CONDITION
(FORM 1-8)
I FOR
CARLSBAD OAKS NORTH BUSINESS PARK - LOT 5 I CARLSBAD, CALIFORNIA
I PROJECT NO. 06442-32-27
I
I
I
I
I
I
I
Appendix I: Forms and Checklists
Psrt 1- Full:inflkationFeas1blliyScreeningCtiteda
Would infiltration of the fultdeaIgnvolume be feasible from a physicalperspectie without any, undesirable
consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
Is the estimated reliable infiltration rate below proposed
facility locations greater than 0.5 inches per hour? The response
I to this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.2 and Appendix
D.
Provide basis:
See page 3, Sections 4.0 and page 24. 8.11 of the project update geotechnical report, the site is currently and will
e underlain by dense compacted fill and granitic rock at grade after completion of grading. The compacted fill
onsists of silty sands, and mixtures of angular gravel and boulders with sandy clays placed in deeper fill areas. It
s our opinion the compacted fill is unsuitable for infiltration of storm water runoff due to the potential for adverse
ettlement and slope instability. The granitic bedrock is also sufficiently dense that infiltration water would be
xpected to perch on granitic rock.
Can infiltration greater than 0.5 inches per hour be allowed
without increasing risk of geotechnical hazards (slope stability,
2 groundwater mounding, utilities, or other factors) that cannot
be mitigated to an acceptable level? The response to this
Screening Question shall be based on a comprehensive evaluation of
the factors presented in Appendix C.2.
Provide basis:
As discussed above, the site is currently and will be underlain by dense compacted fill and granitic rock at grade
after completion of grading. It is our opinion the compacted fill is unsuitable for infiltration of storm water runoff
due to the potential for adverse settlement and slope instability. The granitic bedrock is also sufficiently dense that
infiltration water would be expected to perch on granitic rock.
I
I
I
I
I
I
I
11
I
I
I
I
I
~1
I
Li
I
1-3 February 2016
I
1
I
I
1
I
I
I
I
I
I
I
1
I
I
I
I
I
I
I
Appendix I: Forms and Checklists
Criteria SnreeningQuestiou Yes No
Can infiltration greater than 0.5 inches per hour be allowed
without increasing risk of groundwater contamination (shallow
water table, storm water pollutants or other factors) that cannot
be mitigated to an acceptable level? The response to this
Screening Question shall be based on a comprehensive evaluation of
the factors presented in Appendix C.3.
Provide basis:
Can infiltration greater than 0.5 inches per hour be allowed
without causing potential water balance issues such as change
of seasonality of ephemeral streams or increased discharge of
contaminated groundwater to surface waters? The response to
this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.3.
Provide basis:
If all answers to rows I - 4 are "Yes" a full infiltration design is potentially feasible.
Part I The feasibility screening category is Full Infiltration
Result If any answer from row 1-4 is "No", infiltration may be possible to some extent but NO
would not generally be feasible or desirable to achieve a "full infiltration" design.
Proceed to Part 2
*To be completed using gathered site information and best professional judgment considering the definition of MEP in
the MS4 Permit. Additional testing and/or studies may be required by the City to substantiate findings.
1-4 February 2016
Appendix I: Forms and Checklists
1art2 —PjiflaUnflltrtion vs. No rnfijUauoneasibiiity Sc niqgCricn
Would mifitration of water in any appreciable amount be physically feasible without any negative
consequences that cannot be Ecasonably mitigated?
Criteria Screening Question. Yes No
Do soil and geologic conditions allow for infiltration in any
5 appreciable rate or volume? The response to this Screening
Question shall be based on a comprehensive evaluation of the
factors presented in Appendix C.2 and Appendix D.
Provide basis:
As discussed in Part 1, the Site is currently and will be underlain by dense compacted fill and granitic rock at
grade after completion of grading. It is our opinion the compacted fill is unsuitable for infiltration of storm water
runoff due to the potential for adverse settlement and slope instability. The granitic bedrock is also sufficiently
dense that infiltration water would be expected to perch on granitic rock.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
Can Infiltration in any appreciable quantity be allowed
without increasing risk of geotechnical hazards (slope
6 stability, groundwater mounding, utilities, or other factors) VO
that cannot be mitigated to an acceptable level? The response
to this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.2.
Provide basis:
See response to criteria 5.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
1-5 February 2016
I
Fj
I
d
I
I
I
I
I
I
I
Lj
I
I
I
I
I
Appendix I: Forms and Checklists
Ctitefia Screening Question Yes No
Can Infiltration in any appreciable quantity be allowed
without posing significant risk for groundwater related
concerns (shallow water table, storm water pollutants or other
factors)? The response to this Screening Question shall be based
on a comprehensive evaluation of the factors presented in
Appendix C.3.
Provide basis:
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
Can infiltration be allowed without violating downstream
8 water rights? The response to this Screening Question shall be
based on a comprehensive evaluation of the factors presented in
Appendix C.3.
Provide basis:
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
If all answers from row 5-8 are yes then partial infiltration design is potentially feasible.
Part 2 The feasibility screening category is Partial Infiltration. NO
Result* i i If any answer from row 5-8 s no, then infiltration of any volume s considered to be Infiltration
infeasible within the drainage area. The feasibility screening category is No Infiltration.
*To be completed using gathered site information and best professional judgment considering the definition of IlEP in
the MS4 Permit, Additional testing and/or studies may be required by the City to substantiate findings.
1-6 February 2016
I
I
I
I
Lii
I
LI
I
I
I
[1
1
I
I
I
I
Li
I
I
I
I
I
I
I
I
I
I
APPENDIX
1
I
I
I
El
I i
I
I
[1
I
I
1
Fi
I APPENDIX D
RECOMMENDED GRADING SPECIFICATIONS
FOR
I CARLSBAD OAKS NORTH BUSINESS PARK - LOT 5
CARLSBAD, CALIFORNIA
PROJECT NO. 06442-32-27
I
I
Li
I
I
I
1
I
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. 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 conformance 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 them 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 in 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 moisture
condition, inadequate compaction, and/or adverse weather result in a quality of work not in
conformance with these specifications, the Consultant will be empowered to reject the
work and recommend to the Owner that grading be stopped until the unacceptable
conditions are corrected.
2. DEFINITIONS
2.1 Owner shall refer to the owner of the property or the entity on whose behalf the grading
work is being performed and who has contracted with the Contractor to have grading
performed.
2.2 Contractor shall refer to the Contractor performing the site grading work.
2.3 Civil Engineer or Engineer of Work shall refer to the California licensed Civil Engineer
or consulting firm responsible for preparation of the grading plans, surveying and verifying
as-graded topography.
2.4 Consultant shall refer to the soil engineering and engineering geology consulting firm
retained to provide geotechnical services for the project.
GI rev. 07/2015
I
I
[1
I
I
I
Li
1
I
I
I
I
I
i
I
I
El
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 conformance 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 3/4 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 than 3 feet
in maximum dimension and containing little or no fines. Fines are defined as
material smaller than 1/4 inch in maximum dimension. The quantity of fines shall be
less than approximately 20 percent of the rock fill quantity.
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
defined by the California Code of Regulations, Title 22, Division 4, Chapter 30, Articles 9
GI rev. 07/2015
I
I
I
I
I
[]
LI
I
I
I
I
I
I
I
LI
F1
I
I
[TI
and 10; 40CFR; and any other applicable local, state or federal laws. The Consultant shall I 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
I 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
I suspected materials are not hazardous as defined by applicable laws and regulations.
I 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 (horizontal: vertical) and a soil I 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
I Consultant.
I
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
I
appropriate, shear strength, expansion, and gradation characteristics of the 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.
1 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
I complete removal above the ground surface of trees, stumps, brush, vegetation, man-made
structures, and similar debris. Grubbing shall consist of removal of stumps, roots, buried
I logs and other unsuitable material and shall be performed in areas to be graded. Roots and
other projections exceeding 11/2 inches in diameter shall be removed to a depth of 3 feet
below the surface of the ground. Borrow areas shall be grubbed to the extent necessary to
I provide suitable fill materials.
1 4.2 Asphalt pavement material removed during clearing operations should be properly
disposed at an approved off-site facility or in an acceptable area of the project evaluated by
I
Geocon and the property owner. 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.
Li
1
GI rev. 07/2015
I
I
- 4.3 After clearing and grubbing of organic matter and other unsuitable material, loose or
I porous soils shall be removed to the depth recommended in the Geotechnical Report. The
depth of removal and compaction should be observed and approved by a representative of
I 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
,I
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
I where recommended by the Consultant, the original ground should be benched in
accordance with the following illustration.
I TYPICAL BENCHING DETAIL
Finish Grade Original Ground
I Finish Slope Surface
I Remove All
Unsuitable Material
I
As Recommended By
Consultant Slope To Be Such That
Sloughing Or Sliding
Does Not Occur Varies
I See Note 1 - See Note 2
I No Scale
I
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.
LI
1 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.
11
GI rev. 07/2015
I
i
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 constructed 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.
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 bladinglmixing, or other satisfactory methods until the moisture
content is within the range specified.
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
determined in accordance with ASTM D 1557. 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.
GI rev. 07/2015
I
I
1
I
I
I
I
I
I
I
I
I
I
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 soil 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 dozer
or similar equipment, such that a dozer track covers all slope surfaces at least
twice.
6.2 Soil-rock fill, 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.
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, the 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.
GI rev. 07/2015
U
I
U
Li
I
I
I
I
I
I
i
I
I
I
I
I
I
1
I
Li
6.2.5 Windrows should generally be parallel to each other and may be placed either
I 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
I 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
I
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:
I
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
I . pressure buildup does not develop. The subdrains shall be permanently connected
to controlled drainage facilities to control post-construction infiltration of water.
1 6.3.2 Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock
trucks traversing previously placed lifts and dumping at the edge of the currently
I 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 trucks traversing in front of the current rock lift face and spraying
I water continuously during rock placement. Compaction equipment with
compactive energy comparable to or greater than that of a 20-ton steel vibratory
I roller or other compaction equipment providing suitable energy to achieve the
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
I 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.
1 6.3.3 Plate bearing tests, in accordance with ASTM D 1196, may be performed in both
the compacted soil fill and in the rock fill to aid in determining the required
I minimum number of passes of the compaction equipment. If performed, a
minimum of three plate bearing tests should be performed in the properly
I compacted soil fill (minimum relative compaction of 90 percent). Plate bearing
tests shall then be performed on areas of rock fill having two passes, four passes
and six passes of the compaction equipment, respectively. The number of passes
I required for the rock fill shall be determined by comparing the results of the plate
bearing tests for the soil fill and the rock fill and by evaluating the deflection
I
GI rev. 07/2015
I
variation with number of passes. The required number of passes of the compaction
equipment will be performed as necessary until the plate bearing deflections are
equal to or less than that determined for the properly compacted soil fill. In no case
will the required number of passes be less than two.
I
1
I
I
I
1
I
I
7.1
1
I
I
I
I
I
I
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 determined 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 soil
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 determined 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.
7. SUBDRAINS
The geologic units on the site may have permeability characteristics and/or fracture
systems that could be susceptible under certain conditions to seepage. The use of canyon
subdrains may be necessary to mitigate the potential for adverse impacts associated with
seepage conditions. Canyon subdrains with lengths in excess of 500 feet or extensions of
existing offsite subdrains should use 8-inch-diameter pipes. Canyon subdrains less than 500
feet in length should use 6-inch-diameter pipes.
GI rev. 07/2015
I
I
I
I
I
I
I
I
V
I
I
I
I
I
I
I
I
I
I
I
I
TYPICAL CANYON DRAIN DETAIL
-'N
- .--.-ALLUMM _.:T
COURAN
BEOCK
WMDEIALMOK - -
Mm
c*aa Qay. BL aY
ia
NOtE$-.
AMtDU18O V
*xcss oi P APtpLENG114oF LONOEEL
IAN ImFiO N CRAPWTh SHOMkTHAN SM RIM
NOSCALJE
7.2 Slope drains within stability fill keyways should use 4-inch-diameter (or lager) pipes.
GI rev. 07/205
I
I
U
I
I
I
I
TYPICAL STABILITY FILL DETAIL
I
P1P F RT1ALUA1¼WJNOA M*IMM9
I a
M tAMTEA Tb dMMAN64,b& NAY awL
I EUVALET AD&1 CA AT t tci IM 'iJ urLrT
I N9MJ
7.3 The actual subdrain locations will be evaluated in the field during the remedial grading
operations. Additional drains may be necessary depending on the conditions observed and
I the requirements of the local regulatory agencies. Appropriate subdrain outlets should be
evaluated prior to finalizing 40-scale grading plans.
7.4 Rock fill or soil-rock fill areas may require subdrains along their down-slope perimeters to
I'
mitigate the potential for buildup of water from construction or landscape irrigation. The
subdrains should be at least 6-inch-diameter pipes encapsulated in gravel and filter fabric.
Rock fill drains should be constructed using the same requirements as canyon subdrains.
I
I
GI rev. 07/2015
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
7.5 Prior to outletting, the final 20-foot segment of a subdrain that will not be extended during
future development should consist of non-perforated drainpipe. At the non-perforated/
perforated interface, a seepage cutoff wall should be constructed on the downslope side of
the pipe.
TYPICAL CUT OFF WALL DETAIL
FRONT VIEW
SIDE ;Vl:EW
7.6 Subdrains that discharge into a natural drainage course or open space area should be
provided with a permanent headwall structure.
GI rev. 07/2015
qrwrl
TYPICAL HEADWALL DETAIL
FONT VIEW
'00 OCALE
SE
OR W0CQNTRMMM3WVMECPAR4kGE
7.7 The final grading plans should show the location of the proposed subdrains. After
completion of remedial excavations and subdrain installation, the project civil engineer
should survey the drain locations and prepare an "as-built" map showing the drain
locations. The final outlet and connection locations should be determined during grading
operations. Subdrains that will be extended on adjacent projects after grading can be placed
on formational material and a vertical riser should be placed at the end of the subdrain. The
grading contractor should consider videoing the subdrains shortly after burial to check
proper installation and functionality. The contractor is responsible for the performance of
the drains.
GI rev. 07/2015
I
8. OBSERVATION AND TESTING
1 8.1 The Consultant shall be the Owner's representative to observe and perform tests during
clearing, grubbing, filling, and compaction operations. In general, no more than 2 feet in
I vertical elevation of soil 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
I should be performed for every 2,000 cubic yards of soil or soil-rock fill placed and
compacted.
1 8.2 The Consultant should perform a sufficient distribution of field density tests of the
compacted soil or soil-rock fill to provide a basis for expressing an opinion whether the fill
I material is compacted as specified. Density tests shall be performed in the compacted
materials below any disturbed surface. When these tests indicate that the density of any
I 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.
1 8.3 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
I 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
I 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.
8.4 A settlement monitoring program designed by the Consultant may be conducted in areas of
I rock fill placement. The specific design of the monitoring program shall be as
recommended in the Conclusions and Recommendations section of the project
1 Geotechnical Report or in the final report of testing and observation services performed
during grading.
1 8.5 We should observe the placement of subdrains, to check that the drainage devices have
I
been placed and constructed in substantial conformance with project specifications.
8.6 Testing procedures shall conform to the following Standards as appropriate:
8.6.1 Soil and Soil-Rock Fills:
1 8.6.1.1 Field Density Test, ASTM D 1556, Density of Soil In-Place By the
Sand-Cone Method.
I
GI rev. 07/2015
I
8.6.1.2 Field Density Test, Nuclear Method, ASTM D 6938, Density of Soil and
Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth).
8.6.1.3 Laboratory Compaction Test, ASTM D 1557, Moisture-Density
Relations of Soils and Soil-Aggregate Mixtures Using 10-Pound
Hammer and 18-Inch Drop.
8.6.1.4. Expansion Index Test, ASTM D 4829, Expansion Index Test.
9. PROTECTION OF WORK
9.1 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 structures.
9.2 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.
10. CERTIFICATIONS AND FINAL REPORTS
10.1 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 obstructions.
10.2 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 California licensed Civil Engineer experienced in
geotechnical engineering and by a California Certified Engineering Geologist, indicating
that the geotechnical aspects of the grading were performed in substantial conformance
with the Specifications or approved changes to the Specifications.
I
I
I
I
I
I
I
I
I
I
ri
I
I
I
I
I
I
I
GI rev. 07/2015
I
L
LIST OF REFERENCES
I
1. Boore, D. M., and G. M Atkinson (2006), Boore-Atkinson NGA Ground Motion Relations for
I the Geometric Mean Horizontal Component of Peak and Spectral Ground Motion
Parameters, Report Number PEER 2007/0 1, May 2007.
I 2. Brain S. J. Chiou, and Robert R. Youngs, A NGA Model for the Average Horizontal
Component of Peak Ground Motion and Response Spectra, preprint for article to be
published in NGA Special Edition for Earthquake Spectra, Spring 2008.
I 3. California Geological Survey, Seismic Shaking Hazards in California, Based on the
USGS/CGS Probabilistic Seismic Hazards Assessment (PSHA) Model, 2002 (revised April
2003). 10% probability of being exceeded in 50 years.
I
Campbell, K. W., Y. Bozorgnia, NGA Ground Motion Model for the Geometric Mean
I Horizontal Component of PGA, PGV, PGD and 5% Damped Linear Elastic Response
Spectra for Periods. Ranging from 0.01 to 10 s, Preprint of version submitted for publication
in the NGA Special Volume of Earthquake Spectra, Volume 24, Issue 1, pages 139-171,
I February 2008.
Fault Activity Map of California and Adjacent Areas, California Division of Mines and
I Geology, compiled by C. W. Jennings, 1994.
Kennedy, M. P., and S. S. Tan, Geologic Map of the Oceanside 30 'x60' Quadrangle,
I
California, USGS Regional Map Series Map No. 2, Scale 1:100,000, 2007.
Wesnousky, S. G., Earthquakes, Quaternary Faults, and Seismic Hazard in California,
I
Journal of Geophysical Research, Vol. 91, No. B12, 1986, pp. 12, 587, 631.
Risk Engineering, EZ-FRISK (version 7.65), 2011.
I 9. Unpublished reports and maps on file with Geocon Incorporated.
10. USGS computer program, Seismic Hazard Curves and Uniform Hazard Response Spectra
(version 5.1.0), February 10, 2011.
I
I
I
I
I
Project No. 06442-32-27 June 24, 2016
1