HomeMy WebLinkAboutAppendix E - Geotechnical Investigation131 Calle Iglesia, Suite 200, San Clemente, CA 92672 (949) 369-6141 www.lgcgeotechnical.com
February 25, 2022 Project No. 21301-01
Mr. Jeremy Krout
EPD Solutions, Inc.
2 Park Plaza Suite 1120
Irvine, CA 92614
Subject: Preliminary Geotechnical Evaluation, Proposed Industrial Development, 14387
Valley Boulevard, Fontana, California
In accordance with your request, LGC Geotechnical, Inc. has performed a geotechnical evaluation for the
proposed industrial development located at 14387 Valley Boulevard in the City of Fontana, California.
This report summarizes the results of our background review, subsurface exploration, and geotechnical
analyses of the data collected, and presents our findings, conclusions, and preliminary
recommendations for the proposed development.
If you should have any questions regarding this report, please do not hesitate to contact our office. We
appreciate this opportunity to be of service.
Respectfully,
LGC Geotechnical, Inc.
Ryan Douglas, PE, GE 3147
Project Engineer
RLD/BPP/amm
Distribution: (1) Addressee (electronic copy)
Project No. 21301‐01 Page i February 25, 2022
TABLE OF CONTENTS
Section Page
1.0 INTRODUCTION .......................................................................................................................... 1
1.1 Purpose and Scope of Services ............................................................................................... 1
1.2 Existing Site Conditions and Proposed Improvements .............................................. 1
1.3 Subsurface Evaluation ............................................................................................................... 2
1.4 Laboratory Testing ..................................................................................................................... 2
2.0 GEOTECHNICAL CONDITIONS ............................................................................................... 5
2.1 Regional Geology .......................................................................................................................... 5
2.2 Site Geology and Generalized Subsurface Conditions ................................................... 5
2.3 Groundwater.................................................................................................................................. 5
2.4 Field Infiltration Testing ........................................................................................................... 6
2.5 Faulting and Seismic Hazards ................................................................................................. 6
2.5.1 Liquefaction and Dynamic Settlement ................................................................ 7
2.5.2 Lateral Spreading ......................................................................................................... 7
2.6 Seismic Design Criteria .............................................................................................................. 8
2.7 Oversized Material ...................................................................................................................... 9
2.8 Expansion Potential .................................................................................................................. 10
3.0 CONCLUSIONS........................................................................................................................... 11
4.0 RECOMMENDATIONS ............................................................................................................. 12
4.1 Site Earthwork ............................................................................................................................ 12
4.1.1 Site Preparation ........................................................................................................... 12
4.1.2 Removal and Recompaction Depths and Limits ............................................. 13
4.1.3 Temporary Excavations ........................................................................................... 14
4.1.4 Subgrade Preparation ............................................................................................... 14
4.1.5 Material for Fill ............................................................................................................. 14
4.1.6 Placement and Compaction of Fills ...................................................................... 15
4.1.7 Trench and Retaining Wall Backfill and Compaction ................................... 16
4.1.8 Shrinkage and Subsidence ...................................................................................... 17
4.2 Preliminary Foundation Recommendations ................................................................... 17
4.2.1 Slab Design and Construction ............................................................................... 17
4.2.2 Foundation Design Parameters ............................................................................ 18
4.2.3 Foundation Construction ........................................................................................ 19
4.2.4 Lateral Load Resistance ........................................................................................... 19
4.3 Lateral Earth Pressures for Retaining Walls ................................................................. 20
4.4 Corrosivity to Concrete and Metal ..................................................................................... 21
4.5 Preliminary Asphalt Concrete Pavement Sections ..................................................... 22
4.6 Preliminary Portland Cement Concrete Pavement Sections .................................... 23
4.7 Nonstructural Concrete Flatwork ...................................................................................... 24
4.8 Subsurface Water Infiltration ............................................................................................... 24
4.9 Control of Surface Water and Drainage Control ............................................................ 26
TABLE OF CONTENTS (Cont’d)
Project No. 21301‐01 Page ii February 25, 2022
4.10 Geotechnical Plan Review ...................................................................................................... 26
4.11 Geotechnical Observation and Testing .............................................................................. 26
5.0 LIMITATIONS ............................................................................................................................ 28
LIST OF TABLES, ILLUSTRATIONS, & APPENDICES
Tables
Table 1 – Summary of Infiltration Testing (Page 6)
Table 2 – Seismic Design Parameters (Page 9)
Table 3 – Estimated Shrinkage (Page 17)
Table 4 – Allowable Soil Bearing Pressures (Page 19)
Table 5 – Lateral Earth Pressures – On-site or Imported Sandy Backfill (Page 20)
Table 6 – Preliminary Asphalt Concrete Pavement Sections (Page 22)
Table 7 – Preliminary PCC Pavement Sections (Page 23)
Table 8 – Geotechnical Factors of Safety for Design Infiltration Rate (Page 25)
Figures
Figure 1 – Site Location Map (Page 5)
Figure 2 – Boring Location Map (Rear of Text)
Figure 3 – Retaining Wall Backfill Detail (Rear of Text)
Appendices
Appendix A – References
Appendix B – Boring & Geotechnical Trench Logs
Appendix C – Laboratory Test Results
Appendix D – Infiltration Results
Appendix E – General Earthwork and Grading Specifications for Rough Grading
Project No. 21301‐01 Page 1 February 25, 2022
1.0 INTRODUCTION
1.1 Purpose and Scope of Services
This report presents the results of our geotechnical evaluation for the proposed industrial
development located at 14387 Valley Boulevard in the City of Fontana, California. (see Site
Location Map, Figure 1). The purpose of our work was to collect subsurface data in order to
prepare a geotechnical report providing preliminary recommendations for design and
construction of the proposed project. Our scope of services included:
Review of pertinent readily available geotechnical information and geologic maps (Appendix A).
Subsurface investigation including excavation, sampling, and logging of 5 small-diameter
hollow stem borings.
Performed 2 infiltration tests within the hollow stem borings.
Laboratory testing of representative samples obtained during our subsurface investigation
(Appendix C).
Geotechnical analysis and evaluation of the data obtained.
Preparation of this report presenting our preliminary findings, conclusions and
recommendations with respect to the proposed site development.
1.2 Existing Site Conditions and Proposed Improvements
The approximately 4.7-acre site is bound to the north and by Valley Boulevard, to the east and west
by existing parking lot developments and to the south by an undeveloped parcel of land. The site
consists of an existing trailer and on-grade asphalt parking lot for trucks, buses and cars. Review
of historic aerial photographs suggests the following:
1938 through 1948 Aerial Photos: During this time period, the subject site went from undeveloped
land to having a structure built on the northeast corner of the site.
1948 through 1967 Aerial Photos: The site remained relatively unchanged with minor site
improvements.
1967 through 1985 Aerial Photos: The structure in the north eastern corner of the site was
demolished and the pavement currently covering the site appeared.
1985 through 1994 Aerial Photos: By 1994, the structure currently occupying the northern region
of the site had been constructed. The site has remained relatively unchanged since 1994.
Proposed development will consist of one approximately 91,000 square foot industrial building
and supporting improvements. The proposed industrial building is anticipated to be at-grade
concrete tilt-up structure with estimated maximum column and wall loads of approximately 150
kips and 10 kips per linear foot, respectively. Please note no structural loads or preliminary
grading plans were provided to us at the time of this report.
Project No. 21301‐01 Page 2 February 25, 2022
The recommendations provided herein are based upon the estimated structural loading and
layout information above. We understand that the project plans are currently being developed
at this time; LGC Geotechnical should be provided with updated project plans and any changes
to the assumed structural loads when they become available, in order to either confirm or modify
the recommendations provided herein. Additional field work and/or laboratory testing may be
necessary.
1.3 Subsurface Evaluation
LGC Geotechnical performed a subsurface geotechnical evaluation of the site consisting of the
excavation of five hollow-stem auger borings (two of which were used for infiltration testing).
The 3 hollow-stem borings (HS-1 through HS-3) and 2 hollow-stem borings used for infiltration
testing (I-1 and I-2) were drilled to depths ranging from approximately 20 to 22 feet below
existing grade and 10 to 15 feet below existing grade, respectively. An LGC Geotechnical
representative observed the drilling operations, logged the borings, and collected soil samples for
laboratory testing. The borings were excavated using a truck-mounted drill rig equipped with an
8-inch-diameter hollow-stem auger. Driven soil samples were collected by means of the Standard
Penetration Test (SPT) and Modified California Drive (MCD) sampler generally obtained at 2.5
to 5-foot vertical increments. The MCD is a split-barrel sampler with a tapered cutting tip and
lined with a series of 1-inch-tall brass rings. The SPT sampler and MCD sampler were driven
using a 140-pound automatic hammer falling 30 inches to advance the sampler a total depth of
18 inches. The raw blow counts for each 6-inch increment of penetration were recorded on the
boring logs. Bulk samples were also collected and logged at select depths for laboratory testing. At
the completion of drilling, the borings were backfilled with the native soil cuttings and tamped.
Some settlement of the backfill soils may occur over time.
Infiltration testing was performed within two of the borings (I-1 and I-2) at depths ranging from
approximately 10 to 15 feet below existing grade, per the direction of the civil engineer. An LGC
Geotechnical staff engineer installed standpipes, backfilled the boring annulus with crushed
rock, and pre-soaked the infiltration wells prior to testing. Infiltration testing was performed in
accordance with the County of San Bernardino testing guidelines. The infiltration test wells were
subsequently backfilled with native soils at the completion of testing.
The approximate locations of borings are shown on the Boring Location Map (Figure 2). Boring
logs are presented in Appendix B.
1.4 Laboratory Testing
Laboratory testing was performed on representative soil samples obtained from our subsurface
evaluation. Laboratory testing included in-situ moisture and density tests, fines content, Atterberg
limits, consolidation, expansion index, laboratory compaction, direct shear, and corrosion (sulfate,
chloride content, pH, and minimum resistivity).
The following is a summary of the laboratory test results.
Project No. 21301‐01 Page 3 February 25, 2022
Dry density of the samples collected ranged from approximately 96.3 pounds per cubic foot
(pcf) to 135.0 pcf, with an average of approximately 119 pcf. Field moisture contents ranged
from approximately 2 percent to 27 percent, with an average of 5 percent.
One sample tested for fines content indicated a fines content (passing No. 200 sieve) of
approximately 27 percent. According to the Unified Soils Classification System (USCS), the
tested sample is classified as “coarse-grained” soil.
One Atterberg Limit (liquid limit and plastic limit) test was performed. Results indicated a
Plasticity Index (PI) value of 6.
One consolidation test was performed. The deformation versus vertical stress plot is
provided in Appendix C.
One direct shear test was performed. The plot is provided in Appendix C.
One Expansion Index (EI) tests was performed. Results indicate an EI value of 0,
corresponding to “Very Low” expansion potential.
One laboratory compaction tests of a near surface samples indicated a maximum dry density
of 128.5 pcf with an optimum moisture content of 9.0 percent.
Corrosion testing indicated soluble sulfate contents less than approximately 0.01 percent,
chloride content of 60 parts per million (ppm), pH value of 7.98, and minimum resistivity
value of 11,750 ohm-cm.
A summary of the results is presented in Appendix C. The moisture and dry density test results are
presented on the boring logs in Appendix B.
Site Location
Valley Boulevard Cherry AvenueFIGURE 1
Site Location Map
February 2022 DATE
ENG. / GEOL.
PROJECT NO.
PROJECT NAME
SCALE
RLD
Not to Scale
EPD - Fontana
21301-01
Project No. 21301‐01 Page 5 February 25, 2022
2.0 GEOTECHNICAL CONDITIONS
2.1 Regional Geology
The subject site is generally located within the Peninsular Ranges Geomorphic Province of
California, more specifically within the broad San Bernardino Basin that is bounded on the north
by the San Gabriel Mountains. The site is located on a large alluvial fan deposit generated by the
Lytle Creek watershed that emanates from the San Gabriel Range. Regional topography is
dominated by the presence of the faults that define the mountains and hills of the Southern
California region including the Cucamonga Fault that locally defines the southern boundary of the
San Gabriel Range, and the San Jacinto and San Andreas Faults located to the east of the site.
(Morton & Miller, 2003). The current watershed from the San Gabriel Mountains runs several miles
to the northeast of the site at the edge of the Lytle Creek Fan and joins the Santa Ana River Basin
several miles to the south of the site.
2.2 Site Geology and Generalized Subsurface Conditions
Based on review of available geologic maps (Morton & Miller, 2003), the primary geologic unit
underlying the site is mid-Holocene age, Quaternary young alluvial fan deposit. The site is
specifically on the southern edge of the large Lytle Creek alluvial fan deposit. The large, well-
formed fan emanating from the Lytle Creek drainage is largely boulder alluvium in the headward
portion of the fan, grading southward to sand and gravel. As encountered at the subject site, soils
generally consisted of medium dense to very dense sands and silty sands and sands with varying
amounts of gravel to the maximum explored depth of approximately 22 feet below existing grade.
Minor amounts of undocumented artificial fill (undifferentiated on the boring logs) are expected
throughout the site.
It should be noted that borings are only representative of the location and time where/when they
are performed and varying subsurface conditions may exist outside of the performed location. In
addition, subsurface conditions can change over time. The soil descriptions provided above should
not be construed to mean that the subsurface profile is uniform, and that soil is homogeneous
within the project area. For details on the stratigraphy at the exploration locations, refer to
Appendix B.
2.3 Groundwater
Groundwater was not encountered to the maximum explored depth of approximately 22 feet.
Groundwater levels recorded nearby the subject site by the California Department of Water
Resources were measured at depths approximately 300 feet below the ground surface (WDL,
2008).
In general, groundwater levels fluctuate with the seasons and local zones of perched groundwater
may be present within the near-surface deposits due to local seepage or during rainy seasons.
Groundwater conditions below the site may be variable, depending on numerous factors including
seasonal rainfall, local irrigation and groundwater pumping, among others.
Project No. 21301‐01 Page 6 February 25, 2022
2.4 Field Infiltration Testing
Estimation of infiltration rates was performed in general accordance with guidelines set forth by
the County of San Bernardino (2013). In general, a 3-inch diameter perforated PVC pipe was
placed in each borehole to be tested and the annulus was backfilled with gravel, including
placement of about 2 inches of gravel at the bottom of the borehole. The measured infiltration
rates are considered representative of the site soils in the area of the proposed infiltration
system. These measured infiltration rates do not include any factor of safety. Measured
infiltration rates have been normalized to correct the 3-Dimensional flow that occurs within the
field test to 1-Dimensional flow out of the bottom of the boring. The approximate infiltration test
locations are shown on the Boring Location Map (Figure 2) and the infiltration test data is located
in Appendix D and is summarized below in Table 1.
TABLE 1
Summary of Infiltration Testing
Infiltration Test
Location
Infiltration Test
Approx. Depth Below
Existing Grade (ft)
Measured
Infiltration Rate*
(inch/hour)
I-1 10 8.9
I-2 15 7.7
*Normalized to One-Dimensional Flow, does not include any Factor of Safety.
It should be emphasized that infiltration test results are only representative of the location and
depth where they are performed. Varying subsurface conditions may exist outside of the test
locations which could alter the calculated infiltration rates indicated above. Infiltration tests are
performed using relatively clean water free of particulates, silt, etc. Please refer to Section 4.8 for
subsurface water infiltration recommendations.
2.5 Faulting and Seismic Hazards
Prompted by damaging earthquakes in Northern and Southern California, State legislation and
policies concerning the classification and land-use criteria associated with faults have been
developed. The Alquist-Priolo Earthquake Fault Zoning Act was implemented in 1972 to prevent
the construction of urban developments across the trace of active faults. California Geologic Survey
Special Publication 42 was created to provide guidance for following and implementing the law
requirements. Special Publication 42 was most recently revised in 2018 (CGS, 2018). According to
the State Geologist, an “active” fault is defined as one which has had surface displacement within
Holocene time (roughly the last 11,700 years). Regulatory Earthquake Fault Zones have been
delineated to encompass traces of known, Holocene-active faults to address hazards associated
with surface fault rupture within California. Where developments for human occupation are
proposed within these zones, the state requires detailed fault evaluations be performed so that
engineering-geologists can identify the locations of active faults and recommend setbacks from
locations of possible surface fault rupture.
Project No. 21301‐01 Page 7 February 25, 2022
The subject site is not located within a State of California Earthquake Fault Zone (i.e., Alquist-
Priolo Earthquake Fault Act Zone) and no active faults are known to cross the site (CDMG, 2021).
The possibility of damage due to ground rupture is considered low since no active faults are
known to cross the site.
Secondary effects of seismic shaking resulting from large earthquakes on the major faults in the
Southern California region, which may affect the site, include ground lurching, shallow ground
rupture, soil liquefaction and dynamic settlement. These secondary effects of seismic shaking are
a possibility throughout the Southern California region and are dependent on the distance
between the site and causative fault and the onsite geology. Some of the major active nearby
faults that could produce these secondary effects include the San Andreas, San Jacinto, Fontana,
and Cucamonga Faults, among others. A discussion of these secondary effects is provided in the
following sections.
2.5.1 Liquefaction and Dynamic Settlement
Liquefaction is a seismic phenomenon in which loose, saturated, granular soils behave
similarly to a fluid when subject to high-intensity ground shaking. Liquefaction occurs
when three general conditions coexist: 1) shallow groundwater; 2) low density non-
cohesive (granular) soils; and 3) high-intensity ground motion. Studies indicate that
loose, saturated, near-surface, cohesionless soils exhibit the highest liquefaction
potential, while dry, dense, cohesionless soils, and cohesive soils exhibit low to negligible
liquefaction potential. In general, cohesive soils are not considered susceptible to
liquefaction. Effects of liquefaction on level ground include settlement, sand boils, and
bearing capacity failures below structures. Furthermore, dynamic settlement of dry
sands can occur as the sand particles tend to settle and densify as a result of a seismic
event.
The subject site is not located in an area that is susceptible to liquefaction as mapped by
the County of San Bernardino (2007). Based on our field evaluation, site soils are generally
not susceptible to liquefaction due to a lack of groundwater and the dense to very dense
alluvium soils in the upper 50 feet; therefore, liquefaction potential is considered very
low.
2.5.2 Lateral Spreading
Lateral spreading is a type of liquefaction induced ground failure associated with the
lateral displacement of surficial blocks of sediment resulting from liquefaction in a
subsurface layer. Once liquefaction transforms the subsurface layer into a fluid mass,
gravity plus the earthquake inertial forces may cause the mass to move downslope
towards a free face (such as a river channel or an embankment). Lateral spreading may
cause large horizontal displacements and such movement typically damages pipelines,
utilities, bridges, and structures.
Due to the depth to groundwater, very low potential for liquefaction and lack of nearby
“free face” conditions, the potential for lateral spreading is considered very low.
Project No. 21301‐01 Page 8 February 25, 2022
2.6 Seismic Design Criteria
The site seismic characteristics were evaluated per the guidelines set forth in Chapter 16, Section
1613 of the 2019 California Building Code (CBC) and applicable portions of ASCE 7-16 which has
been adopted by the CBC. Please note that the following seismic parameters are only
applicable for code‐based acceleration response spectra and are not applicable for where
site‐specific ground motion procedures are required by ASCE 7‐16. Representative site
coordinates of latitude 34.069941 degrees north and longitude -117.491094 degrees west were
utilized in our analyses. The maximum considered earthquake (MCE) spectral response
accelerations (SMS and SM1) and adjusted design spectral response acceleration parameters (SDS
and SD1) for Site Class D are provided in Table 2 on the following page. Since site soils are Site
Class D, additional adjustments are required to code acceleration response spectrums as
outlined below and provided in ASCE 7-16. The structural designer should contact the
geotechnical consultant if structural conditions (e.g., number of stories, seismically isolated
structures, etc.) require site-specific ground motions.
A deaggregation of the PGA based on a 2,475-year average return period (MCE) indicates that an
earthquake magnitude of 6.94 at a distance of approximately 12.07 km from the site would
contribute the most to this ground motion (USGS, 2014).
Section 1803.5.12 of the 2019 CBC (per Section 11.8.3 of ASCE 7) states that the maximum
considered earthquake geometric mean (MCEG) Peak Ground Acceleration (PGA) should be used
for liquefaction potential. The PGAM for the site is equal to 0.832g (SEAOC, 2022).
Project No. 21301‐01 Page 9 February 25, 2022
TABLE 2
Seismic Design Parameters
Selected Parameters from 2019 CBC,
Section 1613 ‐ Earthquake Loads
Seismic
Design
Values
Notes/Exceptions
Distance to applicable faults classifies the site as a
“Near-Fault” site. Section 11.4.1 of ASCE 7
Site Class D* Chapter 20 of ASCE 7
Ss (Risk-Targeted Spectral Acceleration
for Short Periods) 1.777g From SEAOC, 2022
S1 (Risk-Targeted Spectral
Accelerations for 1-Second Periods) 0.663g From SEAOC, 2022
Fa (per Table 1613.2.3(1)) 1.0
For Simplified Design Procedure
of Section 12.14 of ASCE 7, Fa
shall be taken as 1.4 (Section
12.14.8.1)
Fv (per Table 1613.2.3(2)) 1.7
Value is only applicable per
requirements/exceptions per
Section 11.4.8 of ASCE 7
SMS for Site Class D
[Note: SMS = FaSS] 1.777g -
SM1 for Site Class D
[Note: SM1 = FvS1] 1.127g
Value is only applicable per
requirements/exceptions per
Section 11.4.8 of ASCE 7
SDS for Site Class D
[Note: SDS = (2/3)SMS] 1.184g -
SD1 for Site Class D
[Note: SD1 = (2/3)SM1] 0.751g
Value is only applicable per
requirements/exceptions per
Section 11.4.8 of ASCE 7
CRS (Mapped Risk Coefficient at 0.2 sec) 0.935 ASCE 7 Chapter 22
CR1 (Mapped Risk Coefficient at 1 sec) 0.911 ASCE 7 Chapter 22
*Since site soils are Site Class D and S1 is greater than or equal to 0.2, the seismic response
coefficient Cs is determined by Eq. 12.8-2 for values of T ≤ 1.5Ts and taken equal to 1.5 times
the value calculated in accordance with either Eq. 12.8-3 for TL ≥ T > Ts, or Eq. 12.8-4 for T >
TL. Refer to ASCE 7-16.
2.7 Oversized Material
Oversized material (material larger than 8 inches in maximum dimension) may be encountered
during site grading. Recommendations are provided for appropriate handling of oversized
materials in Appendix E. If feasible, crushing oversized materials onsite or exporting oversized
materials may be considered. Incorporating oversized materials into “rock fills” (windrows, rock
blankets or individual rock burial) is likely not feasible due to the limited depth of grading.
Project No. 21301‐01 Page 10 February 25, 2022
Special handling recommendations should be provided on a case-by-case basis, if necessary.
2.8 Expansion Potential
Based on the results of our preliminary laboratory testing, site soils are anticipated to have a
“Very Low” expansion potential. Final expansion potential of site soils should be determined at
the completion of grading. Results of expansion testing at finish grades will be utilized to confirm
final foundation design.
Project No. 21301‐01 Page 11 February 25, 2022
3.0 CONCLUSIONS
Based on the results of our subsurface geotechnical evaluation, it is our opinion that the proposed
improvements are feasible from a geotechnical standpoint, provided that the recommendations contained
in the following sections are incorporated during site grading and development. A summary of our
geotechnical conclusions are as follows:
As encountered at the subject site, soils generally consisted of medium dense to very dense sands and
silty sands with varying amounts of gravel to the maximum explored depth of approximately 22 feet
below existing grade. The near-surface loose and compressible soils are not suitable for the planned
improvements in their present condition (refer to Section 4.1).
From a geotechnical perspective, onsite soils are anticipated to be suitable for use as general
compacted fill, provided they are screened of construction debris and any oversized material (8 inches
in greatest dimension).
Groundwater was not encountered in our field evaluation. Records indicate groundwater levels
recorded in the area are at depths of approximately 300 feet below existing ground surface.
The subject study area is not located within a mapped State of California Earthquake Fault Zone (i.e.,
Alquist-Priolo Earthquake Fault Act Zone), and based upon our review of published geologic mapping,
no known active or potentially active faults are known to exist within or in the immediate vicinity of
the site. Therefore, the potential for ground rupture as a result of faulting is considered very low.
The main seismic hazard that may affect the site is ground shaking from one of the active regional
faults. The subject site will likely experience strong seismic ground shaking during its design life.
Site soils are generally not susceptible to liquefaction due to a lack of groundwater and dense to very
dense alluvial soils.
Based on the results of preliminary laboratory testing, site soils are anticipated to have “Very Low”
expansion potential. Final design expansion potential must be determined at the completion of
grading.
Oversized material (material larger than 8 inches in maximum dimension) may be encountered
during site grading. Recommendations are provided for appropriate handling of oversized materials
in Appendix E.
Excavations into the existing site soils should be feasible with heavy construction equipment in good
working order. We anticipate that the sandy and silty earth materials generated from the excavations
will be generally suitable for re-use as compacted fill, provided they are relatively free of rocks larger
than 8 inches in dimension, construction debris, and significant organic material.
On-site soils will most likely be suitable for backfill of site retaining walls. Soils that will be used for
retaining wall backfill should be tested and approved by the geotechnical consultant prior to the
backfill of site walls.
Field testing resulted in measured infiltration rates ranging from 7.7 to 8.9 inches per hour. The
measured infiltration rates do not include a factor of safety. Discussion regarding infiltration is
provided in Section 4.8.
Project No. 21301‐01 Page 12 February 25, 2022
4.0 RECOMMENDATIONS
The following recommendations are to be considered preliminary and should be confirmed upon
completion of grading and earthwork operations. In addition, they should be considered minimal from
a geotechnical viewpoint, as there may be more restrictive requirements from the architect, structural
engineer, building codes, governing agencies, or the owner.
It should be noted that the following geotechnical recommendations are intended to provide sufficient
information to develop the site in general accordance with the 2019 CBC requirements. With regard to
the possible occurrence of potentially catastrophic geotechnical hazards such as fault rupture,
earthquake-induced landslides, liquefaction, etc. the following geotechnical recommendations should
provide adequate protection for the proposed development to the extent required to reduce seismic risk
to an “acceptable level.” The “acceptable level” of risk is defined by the California Code of Regulations as
“that level that provides reasonable protection of the public safety, though it does not necessarily ensure
continued structural integrity and functionality of the project” [Section 3721(a)]. Therefore, repair and
remedial work of the proposed improvement may be required after a significant seismic event. With
regards to the potential for less significant geologic hazards to the proposed development, the
recommendations contained herein are intended as a reasonable protection against the potential
damaging effects of geotechnical phenomena such as expansive soils, fill settlement, groundwater
seepage, etc. It should be understood, however, that our recommendations are intended to maintain the
structural integrity of the proposed development and structures given the site geotechnical conditions
but cannot preclude the potential for some cosmetic distress or nuisance issues to develop as a result of
the site geotechnical conditions.
The geotechnical recommendations contained herein must be confirmed to be suitable or modified
based on the actual as-graded conditions.
4.1 Site Earthwork
We anticipate that earthwork at the site will consist of required earthwork removals, precise
grading and construction of the proposed new improvements, including the industrial structures,
subsurface utilities, and vehicular pavement areas.
We recommend that earthwork onsite be performed in accordance with the following
recommendations, future grading plan review report(s), the 2019 CBC/City of Fontana
requirements, and the General Earthwork and Grading Specifications for Rough Grading included
in Appendix E. In case of conflict, the following recommendations shall supersede those included
in Appendix E. The following recommendations may be revised within future grading plan review
reports or based on the actual conditions encountered during site grading.
4.1.1 Site Preparation
Prior to grading, areas to be developed should undergo the stripping and clearing of
vegetation, high organic content soil removal/export and clearing of surface obstructions,
Project No. 21301‐01 Page 13 February 25, 2022
subsurface obstructions, pavements, foundation and slab elements from the site.
Vegetation and debris should be removed and properly disposed of offsite. Holes resulting
from removals of buried obstructions, which extend below proposed remedial and/or
finish grades, should be replaced with suitable compacted fill material.
If cesspools or septic systems are encountered, they should be removed in their entirety.
The resulting excavation should be backfilled with properly compacted fill soils. As an
alternative, cesspools can be backfilled with lean sand-cement slurry. Any encountered
wells should be properly abandoned in accordance with regulatory requirements.
4.1.2 Removal and Recompaction Depths and Limits
In order to provide a relatively uniform bearing condition for the planned improvements,
we recommend the site soils be temporarily removed and recompacted according to the
criteria outlined below. Updated recommendations may be required based on additional
field work, changes to building layouts and actual structural loads.
Buildings: Soils shall be temporarily removed and recompacted to a minimum depth of 5
feet below existing grade or 2 feet below the bottom of foundations, whichever is deeper.
Additionally, existing undocumented fill and unsuitable topsoil encountered within the
building footprints should be removed to suitable native materials and recompacted for
use as compacted fill. Where space is available, the envelope for removal and
recompaction should extend laterally a minimum distance equal to the depth of removal
and recompaction below finish grade or 5 feet beyond the edges of the proposed building
improvements, whichever is larger.
Minor Site Structures: For minor site structures such as free-standing walls, retaining walls,
etc., removal and recompaction should extend at least 3 feet below existing grade or 2 feet
below the base of foundations, whichever is deeper. Where space is available, the envelope
for removal and recompaction should extend laterally a minimum distance of 3 feet beyond
the edges of the proposed minor site structure improvements.
Pavement and Hardscape: Within pavement and hardscape areas, removal and
recompaction should extend to a depth of at least 2 feet below the existing grade or 1 foot
below finished subgrade (i.e., below planned aggregate base/asphalt concrete), whichever
is deeper. In general, the envelope for removal and recompaction should extend laterally a
minimum distance of 2 feet beyond the edges of the proposed pavement and hardscape
improvements.
Local conditions may be encountered during excavation that could require additional over-
excavation beyond the above-noted minimum in order to obtain an acceptable subgrade.
The actual depths and lateral extents of grading will be determined by the geotechnical
consultant, based on subsurface conditions encountered during grading. Removal areas
and areas to be over-excavated should be accurately staked in the field by the Project
Surveyor.
Project No. 21301‐01 Page 14 February 25, 2022
4.1.3 Temporary Excavations
Temporary excavations should be performed in accordance with project plans,
specifications, and applicable Occupational Safety and Health Administration (OSHA)
requirements. Excavations should be laid back or shored in accordance with OSHA
requirements before personnel or equipment are allowed to enter. Based on our field
investigation, the majority of site soils are anticipated to be OSHA Type “C” soils (refer to
the attached boring logs). Sandy soils are present and should be considered susceptible to
caving. Soil conditions should be regularly evaluated during construction to verify
conditions are as anticipated. The contractor shall be responsible for providing the
“competent person” required by OSHA standards to evaluate soil conditions. Close
coordination with the geotechnical consultant should be maintained to facilitate
construction while providing safe excavations. Excavation safety is the sole responsibility
of the contractor.
Vehicular traffic, stockpiles, and equipment storage should be set back from the perimeter
of excavations a minimum distance equivalent to a 1:1 projection from the bottom of the
excavation or 5 feet, whichever is greater. Once an excavation has been initiated, it should
be backfilled as soon as practical. Prolonged exposure of temporary excavations may
result in some localized instability. Excavations should be planned so that they are not
initiated without sufficient time to shore/fill them prior to weekends, holidays, or
forecasted rain.
It should be noted that any excavation that extends below a 1:1 (horizontal to vertical)
projection of an existing foundation will remove existing support of the structure
foundation. If requested, temporary shoring parameters can be provided.
4.1.4 Subgrade Preparation
In general, areas to receive compacted fill should be scarified to a minimum depth of 6
inches, brought to a near-optimum moisture condition (generally within optimum and 2
percent above optimum moisture content), and re-compacted per project requirements.
Removal bottoms and areas to receive fill should be observed and accepted by the
geotechnical consultant prior to subsequent fill placement.
4.1.5 Material for Fill
From a geotechnical perspective, the onsite soils are generally considered suitable for use
as general compacted fill, provided they are screened of organic materials, construction
debris and any oversized material (8 inches in greatest dimension).
From a geotechnical viewpoint, import soils for general fill (i.e., non-retaining wall backfill)
should consist of clean, granular soils of Very Low expansion potential (expansion index of
20 or less based on ASTM D4829). Import for retaining wall backfill should meet the
criteria outlined in the paragraph below. Source samples should be provided to the
Project No. 21301‐01 Page 15 February 25, 2022
geotechnical consultant for laboratory testing a minimum of three working days prior to
any planned importation.
Retaining wall backfill should consist of sandy soils with a maximum of 35 percent fines
(passing the No. 200 sieve) per American Society for Testing and Materials (ASTM) Test
Method D1140 (or ASTM D6913/D422) and a Very Low expansion potential (EI of 20 or
less per ASTM D4829). Soils should also be screened of organic materials, construction
debris, and any material greater than 3 inches in maximum dimension. Most of the on-site
soils should be suitable for retaining wall backfill due to their low fines content (i.e., silt and
clay content) and very low expansion potential; therefore, select grading and stockpiling of
select sandy materials should be anticipated by the contractor. Samples of retaining wall
backfill should be sampled prior to construction to confirm the findings of the investigation.
Aggregate base (crushed aggregate base or crushed miscellaneous base) should conform
to the requirements of Section 200-2 of the Standard Specifications for Public Works
Construction (“Greenbook”) for untreated base materials (except processed miscellaneous
base), the City of Fontana or Caltrans Class 2 aggregate base.
The placement of demolition materials in compacted fill is acceptable from a geotechnical
viewpoint provided the demolition material is broken up into pieces not larger than
typically used for aggregate base (approximately 2 to 4 inches in maximum dimension) and
well blended into fill soils with essentially no resulting voids. Demolition material placed
in fills must be free of construction debris (wood, organics, etc.) and reinforcing steel. If
asphalt concrete fragments will be incorporated into the demolition materials, approval
from an environmental viewpoint may be required and is not the purview of the
geotechnical consultant. From our previous experience, we recommend that asphalt
concrete fragments be limited to fill areas within planned street areas (i.e., not within
building pad areas).
4.1.6 Placement and Compaction of Fills
Material to be placed as fill should be brought to near optimum moisture content (generally
within optimum and 2 percent above optimum moisture content) and recompacted to at
least 90 percent relative compaction (per ASTM D1557). Moisture conditioning of site soils
will be required in order to achieve adequate compaction. Drying and/or mixing the very
moist soils may be required prior to reusing the materials in compacted fills. Generally,
soils are present that will require additional moisture in order to achieve the required
compaction.
The optimum lift thickness to produce a uniformly compacted fill will depend on the type
and size of compaction equipment used. In general, fill should be placed in uniform lifts not
exceeding 8 inches in compacted thickness. Each lift should be thoroughly compacted and
accepted prior to subsequent lifts. Generally, placement and compaction of fill should be
performed in accordance with local grading ordinances and with observation and testing
by LGC Geotechnical. Oversized material as previously defined should be removed from
site fills, if encountered.
Project No. 21301‐01 Page 16 February 25, 2022
During backfill of excavations, the fill should be properly benched into firm and competent
soils of temporary backcut slopes as it is placed in lifts.
Aggregate base material should be compacted to a minimum of 95 percent relative
compaction at or slightly above optimum moisture content per ASTM D1557. Subgrade
below aggregate base should be compacted to a minimum of 90 percent relative
compaction, or in accordance with the City of Fontana requirements, per ASTM D1557 at
near-optimum moisture content (generally within optimum and 2 percent above optimum
moisture content), unless otherwise noted in the pavement recommendations section (see
Sections 4.5 and 4.6).
If gap-graded ¾-inch rock is used for backfill (around storm drain storage chambers,
retaining wall backfill, etc.) it will require compaction. Rock shall be placed in thin lifts
(typically not exceeding 6 inches) and mechanically compacted with observation by
geotechnical consultant. Backfill rock shall meet the requirements of ASTM D2321. Gap-
graded rock is required to be wrapped in filter fabric (Mirafi 140N or approved alternative)
to prevent the migration of fines into the rock backfill.
4.1.7 Trench and Retaining Wall Backfill and Compaction
If trenches are shallow or the use of conventional equipment may result in damage to the
utilities, sand having a sand equivalent (SE) of 30 or greater (per Caltrans Test Method
[CTM] 217) may be used to bed and shade the pipes within the pipe zone. Sand backfill
within the pipe bedding zone may be densified by jetting or flooding and then tamped to
ensure adequate compaction. The onsite soils may generally be considered suitable as
trench backfill (zone defined as 12 inches above the pipe to subgrade), provided the soils
are screened of rocks, construction debris, other material greater than 3 inches in diameter
and significant organic matter. Trench backfill should be compacted in uniform lifts (as
outlined above in Section “Material for Fill”) by mechanical means to at least 90 percent
relative compaction (per ASTM D1557). If gap-graded rock is used for trench backfill, refer
to above Section 4.1.6.
Retaining wall backfill should consist of sandy soils as outlined in preceding Section 4.1.5.
The limits of select sandy backfill should extend at minimum ½ the height of the retaining
wall or the width of the heel (if applicable), whichever is greater, refer to Figure 3 (rear of
text). Retaining wall backfill soils should be compacted in relatively uniform thin lifts to at
least 90 percent relative compaction (per ASTM D1557). Jetting or flooding of retaining
wall backfill materials should not be permitted.
In backfill areas where mechanical compaction of soil backfill is impractical due to space
constraints, typically sand-cement slurry may be substituted for compacted backfill. The
slurry should contain about one sack of cement per cubic yard. When set, such a mix
typically has the consistency of compacted soil. Sand cement slurry placed near the surface
within landscape areas should be evaluated for potential impacts on planned
improvements.
A representative from LGC Geotechnical should observe, probe, and test the backfill to
verify compliance with the project recommendations.
Project No. 21301‐01 Page 17 February 25, 2022
4.1.8 Shrinkage and Subsidence
Volumetric changes in earth quantities will occur when excavated onsite earth materials
are replaced as properly compacted fill. The following is an estimate of shrinkage factors
for the various soil types found onsite. These estimates are based on in-place densities of
the various materials and on the estimated average degree of relative compaction that will
be achieved during grading.
TABLE 3
Estimated Shrinkage
Soil Type Allowance Estimated Range
Artificial Fill & Alluvium Shrinkage 0% to 10 %
Subsidence due to earthwork equipment is expected to be on the order of 0.1 feet. It should
be stressed that these values are only estimates and that actual shrinkage factors are
extremely difficult to predict. These values are estimates only and exclude losses due to
removal of vegetation or debris. The effective change in volume of onsite soils will depend
primarily on the type of compaction equipment, method of compaction used onsite by the
contractor, and accuracy of the topographic survey. The above shrinkage estimates are
intended as an aid for others in determining preliminary earthwork quantities. However,
these estimates should be used with some caution since they are not absolute values.
4.2 Preliminary Foundation Recommendations
The proposed structures may be supported on spread or continuous footings and conventional
slabs, provided earthwork is performed in accordance with the recommendations presented in
this report. Since the site soils are anticipated to be “Very Low” expansion potential (EI of 20 or
less per ASTM D4829), special design considerations from a geotechnical perspective are not
anticipated, however, this must be verified based on as-graded conditions. Footings should be
supported on properly compacted fill. Please note that the following foundation recommendations
are preliminary and must be confirmed by LGC Geotechnical at the completion of grading.
Preliminary foundation recommendations are provided in the following sections. The foundation
design must be performed by the structural engineer based on the following geotechnical
parameters and minimum values provided.
4.2.1 Slab Design and Construction
From a geotechnical perspective, minimum slab thicknesses of 6 inches and 4 inches are
recommended for new slabs in the warehouse areas and office areas, respectively. Slabs
are to be supported on compacted fill soils properly prepared in accordance with the
recommendations provided in this report. Actual slab reinforcement and thickness
Project No. 21301‐01 Page 18 February 25, 2022
should be determined by the structural engineer based on the imposed loading.
Additional slab-on-grade recommendations can be provided for alternative building
types upon request.
The foundation designer may use a modulus of vertical subgrade reaction (k) of 200
pounds per cubic inch (pounds per square inch per inch of deflection). This value is for a
1-foot by 1-foot square loaded area and should be adjusted by the structural designer for
the area of the proposed footing using the following formula:
k = 200 x [(B+1)/2B]2
k = modulus of vertical subgrade reaction, pounds per cubic inch (pci)
B = foundation width (feet)
It is recommended that subgrade soils below slabs be moisture conditioned in order to
maintain the recommended moisture content up to the time of concrete placement. The
recommended moisture content of the slab subgrade soils should be between optimum
moisture content and approximately 2 percent above optimum moisture content to a
minimum depth of 12 inches. The moisture content of the slab subgrade should be
verified by the geotechnical consultant within 1 to 2 days prior to concrete placement. In
addition, this moisture content should be maintained around the immediate perimeter of
the slab during construction and up to occupancy of the building structures.
The following recommendations are for informational purposes only, as they are
unrelated to the geotechnical performance of the foundation. The following
recommendations may be superseded by the foundation engineer and/or owner. Some
post-construction moisture migration should be expected below the foundation. In
general, interior floor slabs with moisture sensitive floor coverings should be underlain
by a minimum 10 mil thick polyolefin material vapor retarder, which has a water vapor
transmission rate (permeance) of less than 0.03 perms. The need for sand and/or the
sand thickness (above and/or below the vapor retarder) should be specified by the
structural engineer, architect or concrete contactor. The selection and thickness of sand
is not a geotechnical engineering issue and is therefore outside our purview.
4.2.2 Foundation Design Parameters
For the proposed industrial structure, minimum continuous wall and column footing
widths are to be 12 inches and 24 inches, respectively, minimum foundation embedment
is to extend a minimum of 18 inches below the adjacent exterior grade, and interior column
footings should be embedded a minimum of 12 inches beneath the adjacent subgrade. The
following allowable bearing pressures for both continuous and column spread footings
presented in Table 4 on the following page are recommended for corresponding footing
widths and embedments.
Project No. 21301‐01 Page 19 February 25, 2022
TABLE 4
Allowable Soil Bearing Pressures
Allowable Static
Bearing Pressure
(psf)
Minimum Footing
Width
(feet)
Minimum Footing
Embedment*
(feet)
3,000 3 2
2,500 2 1.5
2,000 1 1
* Refers to minimum depth measured below lowest adjacent grade.
These allowable bearing values indicated above (exclusive of the weight of the footings)
are for total dead loads and frequently applied live loads and may be increased by ⅓ for
short duration loading (i.e., wind or seismic loads). The allowable bearing pressures are
applicable for level (ground slope equal to or flatter than 5H:1V) conditions only.
In utilizing the above-mentioned allowable bearing capacity and provided our earthwork
recommendations are implemented, foundation settlement due to structural loads is
anticipated to be on the order of 1-inch or less. Differential static settlement may be taken
as half of the static settlement (i.e., ½-inch over a horizontal span of 40 feet).
4.2.3 Foundation Construction
The foundation is to be excavated into competent compacted artificial fill placed during
grading operations. It is recommended that the foundation subgrade soils be evaluated
by the geotechnical engineer prior to steel and/or concrete placement.
The geotechnical parameters provided herein assume that if the areas adjacent to the
foundations are planted and irrigated, these areas will be designed with proper drainage
and adequately maintained so that ponding, which causes significant moisture changes
below the foundation, does not occur. Our recommendations do not account for excessive
irrigation and/or incorrect landscape design. Plants should only be provided with
sufficient irrigation for life and not overwatered to saturate subgrade soils. Sunken
planters placed adjacent to the foundation should either be designed with an efficient
drainage system or liners to prevent moisture infiltration below the foundation.
4.2.4 Lateral Load Resistance
Resistance to lateral loads can be provided by friction acting at the base of foundations and
by passive earth pressure. For concrete/soil frictional resistance, an allowable coefficient
of friction of 0.35 may be assumed with dead-load forces. An allowable passive lateral earth
pressure of 250 psf per foot of depth (or pcf) to a maximum of 2,500 psf may be used for
the sides of footings poured against properly compacted fill. Allowable passive pressure
Project No. 21301‐01 Page 20 February 25, 2022
may be increased to 340 pcf (maximum of 3,400 psf) for short duration seismic loading.
This passive pressure is applicable for level (ground slope equal to or flatter than 5H:1V)
conditions. Frictional resistance and passive pressure may be used in combination without
reduction. We recommend that the upper foot of passive resistance be neglected if finished
grade will not be covered with concrete or asphalt. The provided allowable passive
pressures are based on a factor of safety of 1.5 and 1.1 for static and seismic loading
conditions, respectively.
4.3 Lateral Earth Pressures for Retaining Walls
The following preliminary lateral earth pressures may be used for site retaining walls. Lateral
earth pressures are provided as equivalent fluid unit weights, in pound per square foot (psf) per
foot of depth or pcf. These values do not contain an appreciable factor of safety, so the retaining
wall designer should apply the applicable factors of safety and/or load factors during design. A soil
unit weight of 120 pcf may be assumed for calculating the actual weight of soil over the wall
footing.
The following lateral earth pressures are presented on Table 5 for approved select granular soils
with a maximum of 35 percent fines (passing the No. 200 sieve per ASTM D-421/422) and Very
Low expansion potential (EI of 20 or less per ASTM D4829). Retaining wall backfill should also be
limited to fill material not exceeding 3 inches in greatest dimension. The wall designer should
clearly indicate on the retaining wall plans the required sandy soil backfill criteria. Most of the on-
site soils should be suitable for retaining wall backfill due to their low fines content (i.e., silt and
clay content) and very low expansion potential; therefore, select grading and stockpiling of select
sandy materials should be anticipated by the contractor.
TABLE 5
Lateral Earth Pressures – On‐site Approved Sandy Backfill
Conditions
Equivalent Fluid Unit Weight
(pcf)
Equivalent Fluid Unit Weight
(pcf)
Level Backfill 2:1 Sloped Backfill
Approved Sandy Soils Approved Sandy Soils
Active 35 55
At-Rest 55 70
If the wall can yield enough to mobilize the full shear strength of the soil, it can be designed for
“active” pressure. If the wall cannot yield under the applied load, the earth pressure will be
higher. The equivalent fluid pressure values assume free-draining conditions. Retaining wall
structures should be provided with appropriate drainage and appropriately waterproofed (Refer
to Figure 3). Please note that waterproofing and outlet systems are not the purview of the
geotechnical consultant. If conditions other than those assumed above are anticipated, the
Project No. 21301‐01 Page 21 February 25, 2022
equivalent fluid pressure values should be provided on an individual-case basis by the geotechnical
consultant.
Surcharge loading effects from any adjacent structures should be evaluated by the retaining wall
designer. In general, structural loads within a 1:1 (horizontal to vertical) upward projection from
the bottom of the proposed retaining wall footing will surcharge the proposed retaining structure.
In addition to the recommended earth pressure, retaining walls adjacent to streets should be
designed to resist vehicular traffic if applicable. Uniform surcharges may be estimated using the
applicable coefficient of lateral earth pressure using a rectangular distribution. A factor of 0.35 and
0.5 may be used for the active and at-rest conditions, respectively. The vertical traffic surcharge
may be determined by the structural designer. The retaining wall designer should contact the
geotechnical engineer for any required geotechnical input in estimating any applicable surcharge
loads.
If required, the retaining wall designer may use a seismic lateral earth pressure increment of 5 pcf
for level backfill conditions. This increment should be applied in addition to the provided static
lateral earth pressure using a “normal” triangular distribution with the resultant acting at H/3 in
relation to the base of the retaining structure (where H is the retained height). For the restrained,
at-rest condition, the seismic increment may be added to the applicable active lateral earth
pressure (in lieu of the at-rest lateral earth pressure) when analyzing short duration seismic
loading. Per Section 1803.5.12 of the 2019 CBC, the seismic lateral earth pressure is applicable to
structures assigned to Seismic Design Category D through F for retaining wall structures
supporting more than 6 feet of backfill height. This seismic lateral earth pressure is estimated using
the procedure outlined by the Structural Engineers Association of California (Lew, et al, 2010).
Soil bearing and lateral resistance (friction coefficient and passive resistance) are provided in
Section 4.2. Earthwork considerations (temporary backcuts, backfill, compaction, etc.) for
retaining walls are provided in Section 4.1 (Site Earthwork) and the subsequent earthwork related
sub-sections.
4.4 Corrosivity to Concrete and Metal
Although not corrosion engineers (LGC Geotechnical is not a corrosion consultant), several
governing agencies in Southern California require the geotechnical consultant to determine the
corrosion potential of soils to buried concrete and metal facilities. We therefore present the
results of our testing with regard to corrosion for the use of the client and other consultants, as
they determine necessary.
Corrosion testing of near-surface bulk samples indicated soluble sulfate contents less than
approximately 0.01 percent, chloride content of approximately 60 parts per million (ppm), pH
value of approximately 7.98, and minimum resistivity value of 11,750 ohm-cm. Based on Caltrans
Corrosion Guidelines (2021), soils are considered corrosive if the pH is 5.5 or less, or the chloride
concentration is 500 ppm or greater, or the sulfate concentration is 1,500 ppm (0.15 percent) or
greater. Based on the test results, soils are not considered corrosive using Caltrans criteria.
Project No. 21301‐01 Page 22 February 25, 2022
Based on laboratory sulfate test results, the near surface soils are designated to a class “S0” per ACI
318, Table 19.3.1.1 with respect to sulfates. Concrete in direct contact with the onsite soils can be
designed according to ACI 318, Table 19.3.2.1 using the “S0” sulfate classification.
Laboratory testing may need to be performed at the completion of grading by the project
corrosion engineer to further evaluate the as-graded soil corrosivity characteristics. Accordingly,
revision of the corrosion potential may be needed, should future test results differ substantially
from the conditions reported herein. The client and/or other members of the development team
should consider this during the design and planning phase of the project and formulate an
appropriate course of action.
4.5 Preliminary Asphalt Concrete Pavement Sections
Based on the field and laboratory testing results as well as our experience with past projects in the
area, we assumed an R-value of 50 for preliminary design purposes and calculated pavement
sections for Traffic Indices of 5.0 (or less) and 7.0. These recommendations must be confirmed
with R-value testing of representative near-surface soils at the completion of grading and after
underground utilities have been installed and backfilled. Final street sections should be confirmed
by the project civil engineer based upon the projected design Traffic Index. Determination of the
Traffic Index is not the purview of the geotechnical consultant. It is our understanding that the City
of Fontana has published minimum asphalt concrete section recommendations which have been
incorporated into the recommendations provided below. If requested, LGC Geotechnical will
provide sections for alternate TI values.
TABLE 6
Preliminary Asphalt Concrete Pavement Sections
Assumed Traffic Index 5.0 (or less) 7.0
R ‐Value Subgrade 50 50
AC Thickness 4.0 inches 4.0 inches
CAB Thickness 4.0 inches 6.0 inches
Increasing the thickness of asphalt or adding additional base material will reduce the likelihood
of the pavement experiencing distress during its service life. The above recommendations are
based on the assumption that proper maintenance and irrigation of the areas adjacent to the
roadway will occur through the design life of the pavement. Failure to maintain a proper
maintenance and/or irrigation program may jeopardize the integrity of the pavement.
Earthwork recommendations are provided in Section 4.1 “Site Earthwork” and the related sub-
sections of this report.
Project No. 21301‐01 Page 23 February 25, 2022
4.6 Preliminary Portland Cement Concrete Pavement Sections
Based on the field and laboratory testing results as well as our experience with past projects in
the area, we assumed an R-value of 50 for preliminary design purposes. Preliminary minimum
Portland Cement Concrete (PCC) pavement street sections are provided in Table 7 for Traffic
Indices of 5.0 (or less), 6.0, and 7.0 and may be utilized in the design of the truck
parking/circulation areas or loading docks. These recommendations must be confirmed with R-
value testing of representative near-surface soils at the completion of grading and after
underground utilities have been installed and backfilled. Final street sections should be confirmed
by the project civil engineer based upon the projected design Traffic Index. If requested, LGC
Geotechnical will provide sections for alternate TI values. The appropriate paving section must be
selected by the project civil engineer/client based on design traffic indexes.
TABLE 7
Preliminary PCC Pavement Sections
Provided Traffic Index 5.0 (or less) 6.0 7.0
R ‐Value Subgrade 50 50 50
PCC Thickness 5.5 inches 6.5 inches 7.5 inches
95% Compacted Subgrade 12.0 inches 12.0 inches 12.0 inches
For preliminary planning purposes, the PCC pavement sections may consist of a minimum of
concrete over subgrade soils compacted to 95 percent relative compaction (see Table 7 for section
thicknesses). The concrete should have a minimum compressive strength of 3,250 psi and a
minimum flexural strength of 505 psi at the time the pavement is subjected to traffic. To reduce
the potential (but not eliminate) for cracking, paving should provide control joints at regular
intervals not exceeding 15 feet in each direction, depth of ⅓ the concrete thickness. Contraction
and construction joints should include a joint filler/sealer to prevent migration of water into the
subgrade soils. The type of joint sealer and filler material should be specified by the pavement
designer and should be maintained throughout the life of the pavement. The above section does
not include steel reinforcement. If desired, steel reinforcement should be determined by the
structural engineer.
The thicknesses shown are minimum thicknesses. Increasing the thickness of any or all of the
above layers will reduce the likelihood of the pavement experiencing distress during its service
life. The above recommendations are based on the assumption that proper maintenance and
irrigation of the areas adjacent to the roadway will occur through the design life of the pavement.
Failure to maintain a proper maintenance and/or irrigation program may jeopardize the
integrity of the pavement.
Subgrade below the PCC pavement should be compacted to a minimum of 95 percent relative
compaction per ASTM D1557 near optimum moisture content (generally within optimum and 2
percent above optimum moisture content). Earthwork recommendations are provided in Section
4.1 “Site Earthwork” and the related sub-sections of this report.
Project No. 21301‐01 Page 24 February 25, 2022
4.7 Nonstructural Concrete Flatwork
Nonstructural concrete (such as flatwork, sidewalks, etc.) has a potential for cracking due to
changes in soil volume related to soil-moisture fluctuations. To reduce the potential for excessive
cracking and lifting, concrete should be designed in accordance with the minimum guidelines
outlined below. These guidelines will reduce the potential for irregular cracking and promote
cracking along construction joints but will not eliminate all cracking or lifting. Thickening the
concrete and/or adding additional reinforcement will further reduce cosmetic distress.
Nonstructural and non-vehicular concrete flatwork placed on compacted subgrade may be a
minimum 4-inches in thickness with crack control joints spaced 8 feet apart for flatwork slabs
and 6 feet apart for flatwork sidewalks. Crack control joints should be sawcut or deep open tool
joint to a minimum of 1/3 the concrete thickness. The compacted subgrade below the
nonstructural and non-vehicular concrete flatwork should be wet down prior to placing
concrete.
To reduce the potential for nonstructural concrete flatwork to separate from entryways and
doorways, the owner may elect to install dowels to tie these two elements together.
4.8 Subsurface Water Infiltration
Recent regulatory changes have occurred that mandate that storm water be infiltrated below
grade rather than collected in a conventional storm drain system. It should be noted that
collecting and concentrating surface water for the purpose of intentionally infiltrating it below
grade, conflicts with the geotechnical engineering objective of directing surface water away from
slopes, structures and other improvements. The geotechnical stability and integrity of a site is
reliant upon appropriately handling surface water. In general, we do not recommend that surface
water be intentionally infiltrated into the subsurface soils.
If it is determined that water must be infiltrated due to regulatory requirements, we recommend
the absolute minimum amount of water be infiltrated and that the infiltration areas not be
located near slopes or near settlement sensitive existing/proposed improvements.
Contamination and environmental suitability of the site for infiltration is not the purview of the
geotechnical consultant and should be evaluated by others. LGC Geotechnical only addressed the
geotechnical issues associated with stormwater infiltration.
As with all systems that are designed to concentrate surface flow and direct the water into the
subsurface soils, some minor settlement, nuisance type localized saturation and/or other water
related issues should be expected. Due to variability in geologic and hydraulic conductivity
characteristics, these effects may be experienced at the onsite location and/or potentially at
other locations well beyond the physical limits of the subject site. Infiltrated water may enter
underground utility pipe zones or flow along heterogeneous soil layers or geologic structure and
migrate laterally impacting other improvements which may be located far away or at an
elevation much different than the infiltration source.
Based on the results of our field infiltration testing the measured 1-D infiltration rates for I-1 and
I-2 (not including required factors of safety for design) were 8.9 and 7.7 inches per hour,
Project No. 21301‐01 Page 25 February 25, 2022
respectively. The design infiltration rate shall be determined by dividing the measured
infiltration by a series of safety factors for site suitability and design considerations that are the
purview of both the geotechnical consultant and designer of the infiltration system (County of
San Bernardino, 2013). The recommended geotechnical factors of safety that are to be used to
determine the design infiltration rate are provided in Table 8.
TABLE 8
Geotechnical Factors of Safety for Design Infiltration Rate
A: Site Suitability Considerations (From Table VII.3)
Consideration Factor of Safety (F.S.)
Soil Assessment Methods 2
Texture Class 1
Site Soil Variability 2
Depth to Groundwater/Impervious Layer 1
Calculated Suitability Assessment Factor of Safety 1.5
B: Design Related Considerations (From Table VII.4)
Consideration Factor of Safety (F.S.)
Tributary Size Area Per Infiltration
Designer
Level of Pretreatment Per Infiltration
Designer
Redundancy of Treatment Per Infiltration
Designer
Compaction during Construction 2
Calculated Design Factor of Safety Per Infiltration
Designer
Combined F.S.= Suitability F.S x Design F.S. TBD
The factor of safety used to determine the design infiltration rate is determined by multiplying
the calculated suitability assessment factor of safety of 1.50 by the design factor of safety which
is to be determined by the infiltration system designer. The design infiltration rate is thereby
equal to the Measured Infiltration Rate provided in Table 1 (inches per hour) divided by the
product of 1.50 times the calculated design factor of safety (determined by infiltration designer).
The combined factor of safety must be a minimum of 2.0 but need not exceed 9.0.
Please note that the infiltration values reported herein are for native materials only and are not for
compacted fill. Water discharge from any infiltration systems should not occur within the zone of
influence of foundation footings (column and load bearing wall locations). For preliminary
purposes we recommend a minimum setback of 15 feet from the structural improvements.
Infiltration shall not be permitted directly on or into compacted fill soils. The infiltration values
provided are based on clean water and this requires the removal of trash, debris, soil particles,
etc., and on-going maintenance. Over time, siltation, plugging and clogging of the system may
reduce the infiltration rate and subsequently reduce the effectiveness of the infiltration system.
Project No. 21301‐01 Page 26 February 25, 2022
Any designed infiltration system will require routine periodic maintenance. It should be noted that
methods to prevent this shall be the sole responsibility of the infiltration designer and are not
the purview of the geotechnical consultant. If adequate measures cannot be incorporated into
the design and maintenance of the system, then the infiltration rates may need to be further
reduced. These and other factors should be considered in selecting a design infiltration rate.
We recommend the design of any infiltration system include at least one redundancy or overflow
system. It may be prudent to provide an overflow system connected directly to a storm drain
system in order to prevent failure of the infiltration system, either as a result of lower than
anticipated infiltration with time and/or very high flow volumes.
LGC Geotechnical should be provided with details for any planned required infiltration system
early in the design process for geotechnical input.
4.9 Control of Surface Water and Drainage Control
From a geotechnical perspective, we recommend that compacted finished grade soils adjacent
to proposed structures be sloped away from the proposed structures and towards an approved
drainage device or unobstructed swale. If required, drainage swales, wherever feasible, should
not be constructed within 5 feet of buildings. Where lot and building geometry necessitates that
drainage swales be routed closer than 5 feet to structural foundations, we recommend the use of
area drains together with drainage swales. Drainage swales used in conjunction with area drains
should be designed by the project civil engineer so that a properly constructed and maintained
system will prevent ponding within 5 feet of the foundation. Code compliance of grades is not
the purview of the geotechnical consultant.
Planters with open bottoms adjacent to buildings should be avoided. Planters should not be
designed adjacent to buildings unless provisions for drainage, such as catch basins, liners, and/or
area drains, are made. Overwatering must be avoided.
4.10 Geotechnical Plan Review
Project plans (grading, foundation, retaining wall, etc.) should be reviewed by this office prior to
construction to verify that our geotechnical recommendations have been incorporated. Additional
or modified geotechnical recommendations may be required based on the proposed layout.
4.11 Geotechnical Observation and Testing
The recommendations provided in this report are based on limited subsurface observations and
geotechnical analysis. The interpolated subsurface conditions should be checked in the field during
construction by a representative of LGC Geotechnical. Geotechnical observation and testing is
required per Section 1705 of the 2019 California Building Code (CBC).
Geotechnical observation and/or testing should be performed by LGC Geotechnical at the
following stages:
Project No. 21301‐01 Page 27 February 25, 2022
During grading (removal bottoms, fill placement, etc.);
During retaining wall backfill and compaction;
During utility trench backfill and compaction;
During precise grading;
Preparation of building pads and other concrete-flatwork subgrades, and prior to placement
of aggregate base or concrete;
After building and wall footing excavation and prior to placement of steel reinforcement
and/or concrete;
Preparation of pavement subgrade and placement of aggregate base; and
When any unusual soil conditions are encountered during any construction operation
subsequent to issuance of this report.
Project No. 21301‐01 Page 28 February 25, 2022
5.0 LIMITATIONS
Our services were performed using the degree of care and skill ordinarily exercised, under similar
circumstances, by reputable soils engineers and geologists practicing in this or similar localities. No other
warranty, expressed or implied, is made as to the conclusions and professional advice included in this
report.
This report is based on data obtained from limited observations of the site, which have been extrapolated
to characterize the site. While the scope of services performed is considered suitable to adequately
characterize the site geotechnical conditions relative to the proposed development, no practical
evaluation can completely eliminate uncertainty regarding the anticipated geotechnical conditions in
connection with a subject site. Variations may exist and conditions not observed or described in this report
may be encountered during grading and construction.
This report is issued with the understanding that it is the responsibility of the owner, or of his/her
representative, to ensure that the information and recommendations contained herein are brought to
the attention of the other consultants (at a minimum the civil engineer, structural engineer, landscape
architect) and incorporated into their plans. The contractor should properly implement the
recommendations during construction and notify the owner if they consider any of the
recommendations presented herein to be unsafe, or unsuitable.
The findings of this report are valid as of the present date. However, changes in the conditions of a site
can and do occur with the passage of time, whether they be due to natural processes or the works of
man on this or adjacent properties. The findings, conclusions, and recommendations presented in this
report can be relied upon only if LGC Geotechnical has the opportunity to observe the subsurface
conditions during grading and construction of the project, in order to confirm that our preliminary
findings are representative for the site. This report is intended exclusively for use by the client, any use
of or reliance on this report by a third party shall be at such party’s sole risk.
In addition, changes in applicable or appropriate standards may occur, whether they result from
legislation or the broadening of knowledge. Accordingly, the findings of this report may be invalidated
wholly or partially by changes outside our control. Therefore, this report is subject to review and
modification.
HS-3
T.D. = 20'
HS-2
T.D. = 22'
HS-1
T.D. = 20'
I-1
T.D. = 10'I-2
T.D. = 15'
LEGEND
Approximate Location of Hollow Stem Auger Boring By LGC
Geotechnical, With Total Depth in Feet
Approximate Location of Hollow Stem Auger Infiltration Boring By
LGC Geotechnical, With Total Depth in Feet
Approximate Limits of This Report
HS-3
T.D. = 20'
I-2
T.D. = 15'
FIGURE 1
Boring
Location Map
ENG. / GEOL.
PROJECT NO.
PROJECT NAME
SCALE
DATE
1" = 60'
February 2022
EPD - Fontana
RLD
21301-01LGC Geotechnical, Inc.
131 Calle Iglesia, Ste. 200
San Clemente, CA 92672
TEL (949) 369-6141 FAX (949) 369-6142
4 INCH DIAMETER, SCHEDULE 40 PERFORATED
PVC PIPE TO FLOW TO DRAINAGE DEVICE
SAND BACKFILL
Percent Passing #200 Sieve 35% or Less
and EI 20 or Less
NATIVE BACKFILL COMPACTED
TO MINIMUM 90% RELATIVE
COMPACTION PER ASTM1557-D
MINIMUM 1 CUBIC FOOT PER LINEAR FOOT
BURRITO TYPE SUBDRAIN, CONSISTING OF
3/4 INCH CRUSHED ROCK WRAPPED IN
MIRAFI 140N OR APPROVED EQUIVALENT
FOOTING/WALL PER DESIGN ENGINEER
WATER PROOFING PER DESIGN ENGINEER
12" MINIMUM
18" MAXIMUM
BACKCUT PER OSHA
EXTENT OF FREE DRAINING SAND BACKFILL, MINIMUM
HEEL WIDTH OR H/2 WHICH EVER IS GREATER
WALL HEIGHT, HNOTE:
PLACEMENT OF SUBDRAIN
AT BASE OF WALL WILL NOT
PREVENT SATURATION OF SOILS
BELOW AND / OR IN FRONT OF WALL
FIGURE 3
Retaining Wall
Backfill Detail
February 2022 DATE
ENG. / GEOL.
PROJECT NO.
PROJECT NAME
SCALE
RLD
Not to Scale
EPD - Fontana
21301-01
Appendix A
References
Project No. 21301‐01 A‐1 February 25, 2022
APPENDIX A
References
American Concrete Institute, 2014, Building Code Requirements for Structural Concrete (ACI 318-14) and
Commentary (ACI 318R-14).
American Society of Civil Engineers (ASCE), 2017, Minimum Design Loads for Buildings and Other
Structures, ASCE/SEI 7-16, 2017.
, 2018, Standard 7-16, Minimum Design Loads for Buildings and Associated Criteria for Buildings
and Other Structures, Supplement 1, effective: December 12, 2018.
ASTM International, Annual Book of ASTM Standards, Volume 04.08.
California Building Standards Commission, 2019, California Building Code, California Code of
Regulations Title 24, Volumes 1 and 2, dated July 2019.
California Department of Conservation, Division of Mines and Geology (CDMG), 1997, Guidelines for
Evaluating and Mitigating Seismic Hazards in California, CDMG Special Publication 117.
, 2018, Earthquake Fault Zones, Special Publication 42, Revised 2018.
, 2021, California Earthquake Hazards Zone Application, Retrieved October 27, 2021, from:
https://maps.conservation.ca.gov/cgs/EQZApp/app/.
California Department of Transportation (Caltrans), 2008, Highway Design Manual, Chapter 630, dated
July 2008.
, 2021, Corrosion Guidelines, Version 3.2, dated May 2021.
California Department of Water Resources, Water Data Library Station Map, Retrieved February 18, 2021,
from: http://wdl.water.ca.gov.
California Geological Survey, 2007, Fault-Rupture Hazard Zones in California, Special Publication 42,
Interim Revision 2007.
, 2008, California Geological Society Special Publication 117A: Guidelines for Evaluating and
Mitigating Seismic Hazards in California.
County of San Bernardino, 2007, San Bernardino County Land Use Plan, General Plan, Geologic Hazard
Overlays, FH29C, plot date: May 30, 2007.
, 2013, Technical Guidance Document for Water Quality Management Plans, Infiltration Guidelines,
dated June 21, 2013.
Project No. 21301‐01 A‐2 February 25, 2022
Lew, et al, 2010, Seismic Earth Pressures on Deep Basements, Structural Engineers Association of
California (SEAOC) Convention Proceedings.
Morton & Miller, 2003, Preliminary Digital Geologic Map of the San Bernardino 30’ by 60’ Quadrangle,
Southern California, Open File Report 03-293, USGS Publication, Version 1.0 prepared 2003.
Southern California Earthquake Center (SCEC), 1999, “Recommended Procedure for Implementation of
DMG Special Publication 117, Guidelines for Analyzing and Mitigation Liquefaction Hazards in
California”, Edited by Martin, G.R., and Lew, M., dated March 1999.
Structural Engineers Association of California (SEAOC), 2022, Seismic Design Maps, Retrieved February
18, 2021, from https://seismicmaps.org/
United States Geological Survey (USGS), 2014, Unified Hazard Tool, Dynamic: Conterminous U.S. 2014
(update) (v4.2.0), Retrieved February 18, 2022, from:
https://earthquake.usgs.gov/hazards/interactive/
Appendix B
Boring Logs
THIS SUMMARY APPLIES ONLY AT THE LOCATION
OF THIS BORING AND AT THE TIME OF DRILLING.
SUBSURFACE CONDITIONS MAY DIFFER AT OTHER
LOCATIONS AND MAY CHANGE AT THIS LOCATION
WITH THE PASSAGE OF TIME. THE DATA
PRESENTED IS A SIMPLIFICATION OF THE ACTUAL
CONDITIONS ENCOUNTERED. THE DESCRIPTIONS
PROVIDED ARE QUALITATIVE FIELD DESCRIPTIONS
AND ARE NOT BASED ON QUANTITATIVE
ENGINEERING ANALYSIS.
CN CONSOLIDATION
CR CORROSION
AL ATTERBERG LIMITS
CO COLLAPSE/SWELL
RV R-VALUE
-#200 % PASSING # 200 SIEVE
DIRECT SHEAR
MAXIMUM DENSITY
SIEVE ANALYSIS
SIEVE AND HYDROMETER
EXPANSION INDEX
TEST TYPES:
DS
MD
SA
S&H
EI
SAMPLE TYPES:
B BULK SAMPLE
R RING SAMPLE (CA Modified Sampler)
G GRAB SAMPLE
SPT STANDARD PENETRATION
TEST SAMPLE
GROUNDWATER TABLE
30
25
20
15
10
5
0 Type of TestDESCRIPTIONUSCS SymbolMoisture (%)Dry Density (pcf)Blow CountSample NumberGraphic LogDepth (ft)Elevation (ft)Hole Diameter:
Hole Location: See Geotechnical Map
Drop:
Type of Rig:
Project Number:
Elevation of Top of Hole:Drive Weight:
Drilling Company:
Project Name:
Date:
1030
1025
1020
1015
1010
Geotechnical Boring Log Borehole HS-1
1/26/2022
~1035' MSL
6"
Truck Mounted
30"
140 pounds
Cal Pac
EPD-Fontana
21301-01
Logged By JMN
Sampled By JMN
Checked By RLD
Page 1 of 1
@0'- Gravel: dark gray, dry, loose
R-1 11
1115
@2.5'- Silty SAND with Gravel: olive brown, slightly
moist, medium dense
R-2 13
178
@5'- Silty SAND with Gravel: olive brown, dry, medium
dense
R-3 5
1234
@7.5'- SAND with Silt: olive, moist, dense
R-4 19
2126
@10'- Silty SAND with Gravel: olive, moist, dense
SPT-1 19
2250/6"
@15'- SAND with Silt and Gravel: olive, moist, very
dense
R-5 19
50/6"
@20'- SAND with Gravel: olive gray, dry, very dense
Total Depth = 20'
Groundwater Not Encountered
Backfilled with Cuttings on 1/26/2022B-1Last Edited: 1/28/2022126.0 4.6 SM
118.6 3.2
118.8 9.9 SP-SM
134.9 7.9 SM
118.4 3.2
7.9 SW-SM
SP
@0' to T.D. Young Alluvial-Fan Deposits (Qyf):
THIS SUMMARY APPLIES ONLY AT THE LOCATION
OF THIS BORING AND AT THE TIME OF DRILLING.
SUBSURFACE CONDITIONS MAY DIFFER AT OTHER
LOCATIONS AND MAY CHANGE AT THIS LOCATION
WITH THE PASSAGE OF TIME. THE DATA
PRESENTED IS A SIMPLIFICATION OF THE ACTUAL
CONDITIONS ENCOUNTERED. THE DESCRIPTIONS
PROVIDED ARE QUALITATIVE FIELD DESCRIPTIONS
AND ARE NOT BASED ON QUANTITATIVE
ENGINEERING ANALYSIS.
CN CONSOLIDATION
CR CORROSION
AL ATTERBERG LIMITS
CO COLLAPSE/SWELL
RV R-VALUE
-#200 % PASSING # 200 SIEVE
DIRECT SHEAR
MAXIMUM DENSITY
SIEVE ANALYSIS
SIEVE AND HYDROMETER
EXPANSION INDEX
TEST TYPES:
DS
MD
SA
S&H
EI
SAMPLE TYPES:
B BULK SAMPLE
R RING SAMPLE (CA Modified Sampler)
G GRAB SAMPLE
SPT STANDARD PENETRATION
TEST SAMPLE
GROUNDWATER TABLE
30
25
20
15
10
5
0 Type of TestDESCRIPTIONUSCS SymbolMoisture (%)Dry Density (pcf)Blow CountSample NumberGraphic LogDepth (ft)Elevation (ft)Hole Diameter:
Hole Location: See Geotechnical Map
Drop:
Type of Rig:
Project Number:
Elevation of Top of Hole:Drive Weight:
Drilling Company:
Project Name:
Date:
1040
1035
1030
1025
1020
1015
Geotechnical Boring Log Borehole HS-2
1/26/2022
~1041' MSL
6"
Truck Mounted
30"
140 pounds
Cal Pac
EPD-Fontana
21301-01
Logged By JMN
Sampled By JMN
Checked By RLD
Page 1 of 1
@0'- Gravel: dark gray, dry, loose
R-1 4
610
@2.5'- Silty SAND with Gravel: olive brown, moist,
medium dense
R-2 10
914
@5'- SAND with Gravel: olive, dry, medium dense
R-3 3
410
@7.5- Sandy SILT: olive, wet, stiff
R-4 11
2050/6"
@10'- SAND with Gravel: dark olive, dry, very dense
SPT-1 12
25
40
@15'- SAND with Silt and Gravel: olive, dry, very dense
R-5 23
26
36
@20- Silty GRAVEL: olive gray, dry, dense;
Auger Refusal at 22'
Total Depth = 22'
Groundwater Not Encountered
Backfilled with Cuttings on 1/26/2022B-1Last Edited: 1/28/2022122.1 9.6 SM
116.1 3.1 SP
96.3 26.9 ML
131.6 3.8 SP
3.8 SP-SM
117.2 1.6 GM
CR
DS
EI
MD-#200
@0' to T.D. Young Alluvial-Fan Deposits (Qyf):
THIS SUMMARY APPLIES ONLY AT THE LOCATION
OF THIS BORING AND AT THE TIME OF DRILLING.
SUBSURFACE CONDITIONS MAY DIFFER AT OTHER
LOCATIONS AND MAY CHANGE AT THIS LOCATION
WITH THE PASSAGE OF TIME. THE DATA
PRESENTED IS A SIMPLIFICATION OF THE ACTUAL
CONDITIONS ENCOUNTERED. THE DESCRIPTIONS
PROVIDED ARE QUALITATIVE FIELD DESCRIPTIONS
AND ARE NOT BASED ON QUANTITATIVE
ENGINEERING ANALYSIS.
CN CONSOLIDATION
CR CORROSION
AL ATTERBERG LIMITS
CO COLLAPSE/SWELL
RV R-VALUE
-#200 % PASSING # 200 SIEVE
DIRECT SHEAR
MAXIMUM DENSITY
SIEVE ANALYSIS
SIEVE AND HYDROMETER
EXPANSION INDEX
TEST TYPES:
DS
MD
SA
S&H
EI
SAMPLE TYPES:
B BULK SAMPLE
R RING SAMPLE (CA Modified Sampler)
G GRAB SAMPLE
SPT STANDARD PENETRATION
TEST SAMPLE
GROUNDWATER TABLE
30
25
20
15
10
5
0 Type of TestDESCRIPTIONUSCS SymbolMoisture (%)Dry Density (pcf)Blow CountSample NumberGraphic LogDepth (ft)Elevation (ft)Hole Diameter:
Hole Location: See Geotechnical Map
Drop:
Type of Rig:
Project Number:
Elevation of Top of Hole:Drive Weight:
Drilling Company:
Project Name:
Date:
1040
1035
1030
1025
1020
1015
Geotechnical Boring Log Borehole HS-3
1/26/2022
~1042' MSL
6"
Truck Mounted
30"
140 pounds
Cal Pac
EPD-Fontana
21301-01
Logged By JMN
Sampled By JMN
Checked By RLD
Page 1 of 1
@0'- Gravel: dark gray, dry, loose
R-1 912
15
@2.5'- Silty SAND with Gravel: olive brown, slightly
moist, medium dense
R-2 1318
20
@5'- GRAVEL with Silt: olive brown, dry, medium dense
R-3 63
4
@7.5- Silty CLAY: light olive brown, moist, medium stiff
R-4 1026
25
@10'- SAND with Gravel: olive brown, dry, dense
SPT-1 1950/6"@15'- SAND with Silt and Gravel: olive gray, dry, very
dense
R-5 2250/2"@20'- SAND with Gravel: grayish brown, dry, very
dense
Total Depth = 20'
Groundwater Not Encountered
Backfilled with Cuttings on 1/26/2022B-1Last Edited: 1/28/2022120.8 4.1 SM
135.0 2.0 GP-GM
107.9 12.2 CL-ML
100.4 1.9 SP
2.4 SW-SM
120.5 2.3 SP
AL
CN
@0' to T.D. Young Alluvial-Fan Deposits (Qyf):
THIS SUMMARY APPLIES ONLY AT THE LOCATION
OF THIS BORING AND AT THE TIME OF DRILLING.
SUBSURFACE CONDITIONS MAY DIFFER AT OTHER
LOCATIONS AND MAY CHANGE AT THIS LOCATION
WITH THE PASSAGE OF TIME. THE DATA
PRESENTED IS A SIMPLIFICATION OF THE ACTUAL
CONDITIONS ENCOUNTERED. THE DESCRIPTIONS
PROVIDED ARE QUALITATIVE FIELD DESCRIPTIONS
AND ARE NOT BASED ON QUANTITATIVE
ENGINEERING ANALYSIS.
CN CONSOLIDATION
CR CORROSION
AL ATTERBERG LIMITS
CO COLLAPSE/SWELL
RV R-VALUE
-#200 % PASSING # 200 SIEVE
DIRECT SHEAR
MAXIMUM DENSITY
SIEVE ANALYSIS
SIEVE AND HYDROMETER
EXPANSION INDEX
TEST TYPES:
DS
MD
SA
S&H
EI
SAMPLE TYPES:
B BULK SAMPLE
R RING SAMPLE (CA Modified Sampler)
G GRAB SAMPLE
SPT STANDARD PENETRATION
TEST SAMPLE
GROUNDWATER TABLE
30
25
20
15
10
5
0 Type of TestDESCRIPTIONUSCS SymbolMoisture (%)Dry Density (pcf)Blow CountSample NumberGraphic LogDepth (ft)Elevation (ft)Hole Diameter:
Hole Location: See Geotechnical Map
Drop:
Type of Rig:
Project Number:
Elevation of Top of Hole:Drive Weight:
Drilling Company:
Project Name:
Date:
1030
1025
1020
1015
1010
1005
Geotechnical Boring Log Borehole I-1
1/26/2022
~1033' MSL
8"
Truck Mounted
30"
140 pounds
Cal Pac
EPD-Fontana
21301-01
Logged By JMN
Sampled By JMN
Checked By RLD
Page 1 of 1
@0'- Gravel: dark gray, dry, loose
SPT-1 6
8
9
@2.5'- Silty SAND with Gravel: olive brown, slightly
moist, medium dense
SPT-2 1220
24
@7'- SAND with Silt and Gravel: olive gray, dry, very
dense
Total Depth = 10'
Groundwater Not Encountered
Backfilled with Cuttings on 1/26/2022
Last Edited: 1/28/20226.0 SM
2.1 SW-SM
@0' to T.D. Young Alluvial-Fan Deposits (Qyf):
THIS SUMMARY APPLIES ONLY AT THE LOCATION
OF THIS BORING AND AT THE TIME OF DRILLING.
SUBSURFACE CONDITIONS MAY DIFFER AT OTHER
LOCATIONS AND MAY CHANGE AT THIS LOCATION
WITH THE PASSAGE OF TIME. THE DATA
PRESENTED IS A SIMPLIFICATION OF THE ACTUAL
CONDITIONS ENCOUNTERED. THE DESCRIPTIONS
PROVIDED ARE QUALITATIVE FIELD DESCRIPTIONS
AND ARE NOT BASED ON QUANTITATIVE
ENGINEERING ANALYSIS.
CN CONSOLIDATION
CR CORROSION
AL ATTERBERG LIMITS
CO COLLAPSE/SWELL
RV R-VALUE
-#200 % PASSING # 200 SIEVE
DIRECT SHEAR
MAXIMUM DENSITY
SIEVE ANALYSIS
SIEVE AND HYDROMETER
EXPANSION INDEX
TEST TYPES:
DS
MD
SA
S&H
EI
SAMPLE TYPES:
B BULK SAMPLE
R RING SAMPLE (CA Modified Sampler)
G GRAB SAMPLE
SPT STANDARD PENETRATION
TEST SAMPLE
GROUNDWATER TABLE
30
25
20
15
10
5
0 Type of TestDESCRIPTIONUSCS SymbolMoisture (%)Dry Density (pcf)Blow CountSample NumberGraphic LogDepth (ft)Elevation (ft)Hole Diameter:
Hole Location: See Geotechnical Map
Drop:
Type of Rig:
Project Number:
Elevation of Top of Hole:Drive Weight:
Drilling Company:
Project Name:
Date:
1035
1030
1025
1020
1015
1010
Geotechnical Boring Log Borehole I-2
1/26/2022
~1039' MSL
8"
Truck Mounted
30"
140 pounds
Cal Pac
EPD-Fontana
21301-01
Logged By JMN
Sampled By JMN
Checked By RLD
Page 1 of 1
@0'- Gravel: dark gray, dry, loose
SPT-1 10
99
@2.5'- Silty SAND with Gravel: light olive brown, dry,
medium dense
SPT-2 1928
24
@12'- Silty SAND with gravel: olive, dry, very dense
Total Depth = 15'
Groundwater Not Encountered
Backfilled with Cuttings on 1/26/2022
Last Edited: 1/28/20223.4 SM
3.0
@0' to T.D. Young Alluvial-Fan Deposits (Qyf):
Appendix C
Laboratory Test Results
Project No. 21301‐01 C‐1 February 2022
APPENDIX C
Laboratory Testing Procedures and Test Results
The laboratory testing program was formulated towards providing data relating to the relevant
engineering properties of the soils with respect to residential construction. Samples considered
representative of site conditions were tested in general accordance with American Society for
Testing and Materials (ASTM) procedure and/or California Test Methods (CTM), where applicable.
The following summary is a brief outline of the test type and a table summarizing the test results.
Moisture and Density Determination Tests: Moisture content (ASTM D2216) and dry density
determinations (ASTM D2937) were performed on relatively undisturbed samples obtained from
the test borings and/or trenches. The results of these tests are presented in the boring logs. Where
applicable, only moisture content was determined from undisturbed or disturbed samples.
Expansion Index: The expansion potential of selected samples was evaluated by the Expansion
Index Test, Standard ASTM D4829. Specimens are molded under a given compactive energy to
approximately the optimum moisture content and approximately 50 percent saturation or
approximately 90 percent relative compaction. The prepared 1-inch-thick by 4-inch-diameter
specimens are loaded to an equivalent 144 psf surcharge and are inundated with tap water until
volumetric equilibrium is reached. The results of these tests are presented in the table below.
Sample
Location
Expansion
Index
Expansion
Potential*
HS-2 @ 1-5 feet 0 Very Low
* ASTM D4829
Grain Size Distribution/Fines Content: Representative samples were dried, weighed and soaked in
water until individual soil particles were separated (per ASTM D421) and then washed on a No.
200 sieve (ASTM D1140). Where applicable, the portion retained on the No. 200 sieve and dried
and then sieved on a U.S. Standard brass sieve set in accordance with ASTM D6913 (sieve).
Sample
Location
Description % Passing #
200 Sieve
HS-2 @ 1-5 feet Silty Sand 27
APPENDIX C (Cont’d)
Laboratory Testing Procedures and Test Results
Project No. 21301‐01 C‐2 February 2022
Atterberg Limits: The liquid and plastic limits (“Atterberg Limits”) were determined per
ASTM D4318 for engineering classification of fine-grained material and presented in the table
below. The USCS soil classification indicated in the table below is based on the portion of sample
passing the No. 40 sieve and may not necessarily be representative of the entire sample. The plot
is provided in this Appendix.
Sample Location Liquid Limit
(%)
Plastic Limit
(%)
Plasticity
Index (%)
USCS
Soil
Classification
HS-3 @ 7.5 feet 21 15 6 CL
Consolidation: One consolidation test was performed per ASTM D2435. A sample (2.4 inches in
diameter and 1 inch in height) was placed in a consolidometer and increasing loads were applied.
The sample was allowed to consolidate under “double drainage” and total deformation for each
loading step was recorded. The percent consolidation for each load step was recorded as the ratio
of the amount of vertical compression to the original sample height. The consolidation pressure
curve is provided in this Appendix.
Direct Shear: One direct shear test was performed on remolded samples, which was soaked for a
minimum of 24 hours prior to testing. The samples were tested under various normal loads using
a motor-driven, strain-controlled, direct-shear testing apparatus (ASTM D3080). The plot is
provided in this Appendix.
Maximum Density Tests: The maximum dry density and optimum moisture content of typical
materials were determined in accordance with ASTM D1557. The results of these tests are
presented in the table below:
Sample
Location Sample Description
Maximum
Dry Density
(pcf)
Optimum
Moisture
Content (%)
*HS-2 @ 1-5 feet Olive Brown Silty Sand 128.5 9.0
*Note: These max dry density results are based on a rock correction with approximately 7% retained on
the No. 4 sieve.
APPENDIX C (Cont’d)
Laboratory Testing Procedures and Test Results
Project No. 21301‐01 C‐3 February 2022
Chloride Content: Chloride content was tested in accordance with Caltrans Test Method (CTM)
422. The results are presented below.
Sample Location Chloride Content, ppm
HS-1 @ 1-5 feet 60
Soluble Sulfates: The soluble sulfate contents of selected samples were determined by standard
geochemical methods (CTM 417). The soluble sulfate content is used to determine the appropriate
cement type and maximum water-cement ratios. The test results are presented in the table below.
Sample
Location
Sulfate Content
(ppm)
Sulfate Exposure
Class *
HS-1 @ 1-5 feet 62 S0
*Based on ACI 318R-14, Table 19.3.1.1
Minimum Resistivity and pH Tests: Minimum resistivity and pH tests were performed in general
accordance with CTM 643 and standard geochemical methods. The results are presented in the
table below.
Sample
Location pH Minimum Resistivity
(ohms‐cm)
HS-1 @ 1-5 feet 7.98 11,750
Project Name:Tested By:G. Bathala Date:02/02/22
Project No.:Checked By:J. Ward Date:02/15/22
Boring No.:Depth (ft.):
Sample No.:Sample Type:
Soil Identification:
Sample Diameter (in.):2.415
Sample Thickness (in.):1.000
Weight of Sample + ring (g):192.24
Weight of Ring (g):42.62
Height after consol. (in.):0.9573
Before Test
Wt. of Wet Sample+Cont. (g):246.95
Wt. of Dry Sample+Cont. (g):224.34
Weight of Container (g):39.55
Initial Moisture Content (%)12.2
Initial Dry Density (pcf)110.9
Initial Saturation (%):63
Initial Vertical Reading (in.)0.0888
After Test
Wt. of Wet Sample+Cont. (g):254.45
Wt. of Dry Sample+Cont. (g):233.10
Weight of Container (g):61.47
Final Moisture Content (%) 16.55
Final Dry Density (pcf):112.1
Final Saturation (%):89
Final Vertical Reading (in.)0.1355
Specific Gravity (assumed):2.70
Water Density (pcf):62.43
0.10 0.0889 0.9999 0.00 0.01 0.520 0.01
0.25 0.0908 0.9981 0.05 0.20 0.518 0.15
0.50 0.0930 0.9959 0.13 0.41 0.516 0.28
1.00 0.0972 0.9916 0.22 0.84 0.511 0.62
2.00 0.1027 0.9861 0.34 1.39 0.504 1.05
2.00 0.1048 0.9840 0.34 1.60 0.501 1.26
4.00 0.1142 0.9746 0.48 2.54 0.489 2.06
8.00 0.1293 0.9595 0.64 4.05 0.469 3.41
16.00 0.1493 0.9395 0.86 6.05 0.441 5.19
8.00 0.1467 0.9421 0.72 5.79 0.443 5.07
4.00 0.1441 0.9447 0.61 5.53 0.446 4.92
1.00 0.1387 0.9502 0.46 4.98 0.452 4.53
0.50 0.1355 0.9533 0.40 4.67 0.455 4.27
ONE-DIMENSIONAL CONSOLIDATION
ASTM D 2435
21301-01
Fontana
Deformation
% of Sample
Thickness Square
Root of
Time
Final
Reading
(in.)
Apparent
Thickness
(in.)
Load
Compliance
(%)
HS-3
R-3
Time
Corrected
Deforma-
tion (%)
PROPERTIES of SOILS
Ring
Void
Ratio
Light olive brown silty clay (CL-ML)
Time Readings
Elapsed
Time (min)
7.5
Pressure
(p)
(ksf)Dial Rdgs.
(in.)Date
0.430
0.440
0.450
0.460
0.470
0.480
0.490
0.500
0.510
0.520
0.530
0.10 1.00 10.00 100.Void RatioPressure, p (ksf)
Inundate with
Tap water
Consol HS-3, R-3 @ 7.5
Initial Final Initial Final Initial Final Initial Final
Soil Identification:
Boring
No.
Sample
No.
Depth
(ft.)
Moisture
Content (%)
ONE-DIMENSIONAL CONSOLIDATION
PROPERTIES of SOILS
ASTM D 2435
16.5 112.1HS-3 R-3 12.2
Light olive brown silty clay (CL-ML)
Project No.:
Fontana
02-22
21301-01
Time Readings
0.455 63 89110.9
Degree of
Saturation (%)Dry Density (pcf)
0.520
Void Ratio
7.5
0.0000
0.2000
0.4000
0.6000
0.8000
1.0000
1.20000.1 1.0Deformation Dial Reading (in.)Log of Time (min.)
0.00
1.00
2.00
3.00
4.00
5.00
6.00
0.10 1.00 10.00 100.00Deformation (%)Pressure, p (ksf)
0.0000
0.2000
0.4000
0.6000
0.8000
1.0000
1.20000.0 10.0
Square Root of Time (min.1/2)
Inundate with
Tap water
Project Name:Fontana Tested By:G. Bathala Date:02/07/22
Project No.:21301-01 Checked By:J. Ward Date:02/15/22
Boring No.: Sample Type:90% Remold
Sample No.:Depth (ft.):1-5
Soil Identification:
2.415 2.415 2.415
1.000 1.000 1.000
195.00 195.37 195.29
45.47 45.66 45.43
Before Shearing
182.04 182.04 182.04
172.61 172.61 172.61
69.12 69.12 69.12
0.0000 0.2682 0.2558
-0.0067 0.2795 0.2726
After Shearing
215.90 210.96 193.63
196.94 192.22 175.17
63.80 58.19 40.03
2.70 2.70 2.70
62.43 62.43 62.43
DIRECT SHEAR TEST
Consolidated Drained - ASTM D 3080
Water Density(pcf):
Specific Gravity (Assumed):
Weight of Container(gm):
Weight of Dry Sample+Cont.(gm):
Weight of Ring(gm):
Weight of Container(gm):
Weight of Dry Sample+Cont.(gm):
Weight of Wet Sample+Cont.(gm):
HS-2
Olive silty sand (SM)
Sample Diameter(in):
Weight of Wet Sample+Cont.(gm):
Vertical Rdg.(in): Final
Vertical Rdg.(in): Initial
Sample Thickness(in.):
Weight of Sample + ring(gm):
B-1
DS HS-2, B-1 @ 1-5
Normal Stress (kip/ft²)
Peak Shear Stress (kip/ft²)
Shear Stress @ End of Test (ksf)
Deformation Rate (in./min.)
Initial Sample Height (in.)
Diameter (in.)
Initial Moisture Content (%)
Dry Density (pcf)
Saturation (%)
Soil Height Before Shearing (in.)
Final Moisture Content (%)
114.2
1.000
2.415
9.11
Boring No.
Sample No.
Depth (ft)
HS-2
B-1
1-5
51.6
0.9887
14.0
Soil Identification:9.11
114.1
9.11
114.0
1.380
0.0025
4.000
2.817
2.729
0.0025
1.000
0.802
0.698
0.0025
1.000
2.415
1.000
2.415
2.000
1.506
51.4
0.9933
14.2
FontanaDIRECT SHEAR TEST RESULTS
Consolidated Drained - ASTM D 3080
51.7
0.9832
13.7
02-22
Project No.:21301-01
Sample Type:
90% Remold
Olive silty sand (SM)
0.00
1.00
2.00
3.00
4.00
0 0.1 0.2 0.3Shear Stress (ksf)Horizontal Deformation (in.)
0.00
1.00
2.00
3.00
4.00
0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00Shear Stress (ksf)Normal Stress (ksf)
DS HS-2, B-1 @ 1-5
Appendix D
Infiltration Results
Boring Number:
Test hole dimensions (if circular)
10
8
3
Pre‐Test (Sandy Soil Criteria)*
1 9:20 9:45 25.0 8.17 9.91 1.74
2 9:53 10:18 25.0 8.00 9.86 1.86
Main Test Data
1 10:20 10:30 10.0 7.50 8.75 1.25 7.3
2 10:33 10:43 10.0 8.41 9.35 0.94 8.8
3 10:45 10:55 10.0 8.43 9.33 0.90 8.4
4 10:58 11:08 10.0 8.37 9.39 1.02 9.5
5 11:13 11:23 10.0 8.22 9.35 1.13 9.8
6 11:27 11:37 10.0 8.12 9.23 1.11 8.9
8.929608939
8.9
Sketch: Notes:
Infiltration Test Data Sheet
21301‐01
Boring Diameter (inches):
I‐1
LGC Geotechnical, Inc
131 Calle Iglesia Suite 200, San Clemente, CA 92672 tel. (949) 369‐6141
Project Name:
Boring Depth (feet)*: Pit Depth (feet):
Project Number:
Test pit dimensions (if rectangular)
Date:
*measured at time of test
1/27/2022
EPD‐Fontana
Pipe Diameter (inches): Pit Breadth (feet):
Spreadsheet Revised on: 6/29/2018
Observed Infiltration
Rate(in/hr)
*If two consecutive measurements show that six inches of water seeps away in less than 25 minutes, the test shall be run for an additional hour with
measurements taken every 10 minutes. Otherwise, pre‐soak (fill) overnight, and then obtain at least twelve measurements per hole over at least six hours
(approximately 30 minute intervals) with a precision of at least 0.25 inches
Start Time
(24:HR)
Greater Than or
Equal to
0.5 feet (yes/no)
Stop Time
(24:HR)
Yes
Trial No.
Based on Guidelines from: San Bernardino County (2013)
Pit Length (feet):
Initial Depth to
Water, Do (feet)
Final Depth
to Water, Df
(feet)
Trial No.Time Interval, t
(min)
Start Time
(24:HR)
Stop Time
(24:HR)
Yes
Total Change
in Water Level
(feet)
Observed Infiltration Rate (Does Not Include Any Factor of Safety)
Change in
Water Level,
D (feet)
Time Interval
(min)
Initial Depth to
Water (feet)
Final Depth
to Water
(feet)
Boring Number:
Test hole dimensions (if circular)
15
8
3
Pre‐Test (Sandy Soil Criteria)*
1 9:13 9:38 25.0 11.90 13.69 1.79
2 9:42 10:07 25.0 11.96 13.69 1.73
Main Test Data
1 10:15 10:25 10.0 10.50 13.15 2.65 9.5
2 10:27 10:37 10.0 11.20 13.11 1.91 7.6
3 10:40 10:50 10.0 11.81 13.53 1.72 8.3
4 10:53 11:03 10.0 12.33 13.62 1.29 7.1
5 11:04 11:14 10.0 12.35 13.60 1.25 6.8
6 11:22 11:32 10.0 12.20 13.64 1.44 7.7
7.691394659
7.7
Sketch: Notes:
Infiltration Test Data Sheet
LGC Geotechnical, Inc
131 Calle Iglesia Suite 200, San Clemente, CA 92672 tel. (949) 369‐6141
Project Name:EPD‐Fontana
Project Number:18060‐01
Date:1/27/2022
I‐2
Test pit dimensions (if rectangular)
Boring Depth (feet)*: Pit Depth (feet):
Boring Diameter (inches): Pit Length (feet):
Pipe Diameter (inches): Pit Breadth (feet):
*measured at time of test
Trial No.Start Time
(24:HR)
Stop Time
(24:HR)
Time Interval
(min)
Initial Depth to
Water (feet)
Final Depth
to Water
(feet)
Total Change
in Water Level
(feet)
Greater Than or
Equal to
0.5 feet (yes/no)
Yes
Yes
*If two consecutive measurements show that six inches of water seeps away in less than 25 minutes, the test shall be run for an additional hour with
measurements taken every 10 minutes. Otherwise, pre‐soak (fill) overnight, and then obtain at least twelve measurements per hole over at least six hours
(approximately 30 minute intervals) with a precision of at least 0.25 inches
Trial No.Start Time
(24:HR)
Stop Time
(24:HR)
Time Interval, t
(min)
Initial Depth to
Water, Do (feet)
Based on Guidelines from: San Bernardino County (2013)
Spreadsheet Revised on: 6/29/2018
Final Depth
to Water, Df
(feet)
Change in
Water Level,
D (feet)
Observed Infiltration
Rate(in/hr)
Observed Infiltration Rate (Does Not Include Any Factor of Safety)
Appendix E
General Earthwork and Grading Specifications
for Rough Grading
General Earthwork and Grading Specifications for Rough Grading
1.0 General
1.1 Intent
These General Earthwork and Grading Specifications are for the grading and earthwork
shown on the approved grading plan(s) and/or indicated in the geotechnical report(s). These
Specifications are a part of the recommendations contained in the geotechnical report(s). In
case of conflict, the specific recommendations in the geotechnical report shall supersede these
more general Specifications. Observations of the earthwork by the project Geotechnical
Consultant during the course of grading may result in new or revised recommendations
that could supersede these specifications or the recommendations in the geotechnical report(s).
1.2 The Geotechnical Consultant of Record
Prior to commencement of work, the owner shall employ a qualified Geotechnical Consultant
of Record (Geotechnical Consultant). The Geotechnical Consultant shall be responsible for
reviewing the approved geotechnical report(s) and accepting the adequacy of the preliminary
geotechnical findings, conclusions, and recommendations prior to the commencement of the
grading.
Prior to commencement of grading, the Geotechnical Consultant shall review the "work
plan" prepared by the Earthwork Contractor (Contractor) and schedule sufficient personnel to
perform the appropriate level of observation, mapping, and compaction testing.
During the grading and earthwork operations, the Geotechnical Consultant shall observe,
map, and document the subsurface exposures to verify the geotechnical design assumptions. If
the observed conditions are found to be significantly different than the interpreted
assumptions during the design phase, the Geotechnical Consultant shall inform the owner,
recommend appropriate changes in design to accommodate the observed conditions, and
notify the review agency where required.
The Geotechnical Consultant shall observe the moisture-conditioning and processing of the
subgrade and fill materials and perform relative compaction testing of fill to confirm that the
attained level of compaction is being accomplished as specified. The Geotechnical Consultant
shall provide the test results to the owner and the Contractor on a routine and frequent basis.
1.3 The Earthwork Contractor
The Earthwork Contractor (Contractor) shall be qualified, experienced, and knowledgeable
in earthwork logistics, preparation and processing of ground to receive fill, moisture-
conditioning and processing of fill, and compacting fill. The Contractor shall review and
accept the plans, geotechnical report(s), and these Specifications prior to commencement of
grading. The Contractor shall be solely responsible for performing the grading in accordance
with the project plans and specifications. The Contractor shall prepare and submit to the
owner and the Geotechnical Consultant a work plan that indicates the sequence of earthwork
grading, the number of “equipment” of work and the estimated quantities of daily earthwork
General Earthwork and Grading Specifications for Rough Grading Page 1
contemplated for the site prior to commencement of grading. The Contractor shall inform
the owner and the
Geotechnical Consultant of changes in work schedules and updates to the work plan at least
24 hours in advance of such changes so that appropriate personnel will be available for
observation and testing. The Contractor shall not assume that the Geotechnical Consultant is
aware of all grading operations.
The Contractor shall have the sole responsibility to provide adequate equipment and methods
to accomplish the earthwork in accordance with the applicable grading codes and agency
ordinances, these Specifications, and the recommendations in the approved geotechnical
report(s) and grading plan(s). If, in the opinion of the Geotechnical Consultant, unsatisfactory
conditions, such as unsuitable soil, improper moisture condition, inadequate compaction,
insufficient buttress key size, adverse weather, etc., are resulting in a quality of work less
than required in these specifications, the Geotechnical Consultant shall reject the work and
may recommend to the owner that construction be stopped until the conditions are rectified. It
is the contractor’s sole responsibility to provide proper fill compaction.
2.0 Preparation of Areas to be Filled
2.1 Clearing and Grubbing
Vegetation, such as brush, grass, roots, and other deleterious material shall be sufficiently
removed and properly disposed of in a method acceptable to the owner, governing agencies,
and the Geotechnical Consultant.
The Geotechnical Consultant shall evaluate the extent of these removals depending on
specific site conditions. Earth fill material shall not contain more than 1 percent of organic
materials (by volume). Nesting of the organic materials shall not be allowed.
If potentially hazardous materials are encountered, the Contractor shall stop work in the
affected area, and a hazardous material specialist shall be informed immediately for proper
evaluation and handling of these materials prior to continuing to work in that area.
As presently defined by the State of California, most refined petroleum products (gasoline,
diesel fuel, motor oil, grease, coolant, etc.) have chemical constituents that are considered to be
hazardous waste. As such, the indiscriminate dumping or spillage of these fluids onto the
ground may constitute a misdemeanor, punishable by fines and/or imprisonment, and shall
not be allowed. The contractor is responsible for all hazardous waste relating to his work. The
Geotechnical Consultant does not have expertise in this area. If hazardous waste is a concern,
then the Client should acquire the services of a qualified environmental assessor.
2.2 Processing
Existing ground that has been declared satisfactory for support of fill by the Geotechnical
Consultant shall be scarified to a minimum depth of 6 inches. Existing ground that is not
satisfactory shall be over-excavated as specified in the following section. Scarification shall
continue until soils are broken down and free of oversize material and the working surface is
reasonably uniform, flat, and free of uneven features that would inhibit uniform compaction.
General Earthwork and Grading Specifications for Rough Grading Page 2
2.3 Over-excavation
In addition to removals and over-excavations recommended in the approved geotechnical
report(s) and the grading plan, soft, loose, dry, saturated, spongy, organic-rich, highly
fractured or otherwise unsuitable ground shall be over-excavated to competent ground as
evaluated by the Geotechnical Consultant during grading.
2.4 Benching
Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical units),
the ground shall be stepped or benched. Please see the Standard Details for a graphic
illustration. The lowest bench or key shall be a minimum of 15 feet wide and at least 2 feet
deep, into competent material as evaluated by the Geotechnical Consultant. Other benches
shall be excavated a minimum height of 4 feet into competent material or as otherwise
recommended by the Geotechnical Consultant. Fill placed on ground sloping flatter than 5:1
shall also be benched or otherwise over-excavated to provide a flat subgrade for the fill.
2.5 Evaluation/Acceptance of Fill Areas
All areas to receive fill, including removal and processed areas, key bottoms, and benches,
shall be observed, mapped, elevations recorded, and/or tested prior to being accepted by the
Geotechnical Consultant as suitable to receive fill. The Contractor shall obtain a written
acceptance from the Geotechnical Consultant prior to fill placement. A licensed surveyor
shall provide the survey control for determining elevations of processed areas, keys, and
benches.
3.0 Fill Material
3.1 General
Material to be used as fill shall be essentially free of organic matter and other deleterious
substances evaluated and accepted by the Geotechnical Consultant prior to placement. Soils
of poor quality, such as those with unacceptable gradation, high expansion potential, or low
strength shall be placed in areas acceptable to the Geotechnical Consultant or mixed with other
soils to achieve satisfactory fill material.
3.2 Oversize
Oversize material defined as rock, or other irreducible material with a maximum dimension
greater than 8 inches, shall not be buried or placed in fill unless location, materials, and
placement methods are specifically accepted by the Geotechnical Consultant. Placement
operations shall be such that nesting of oversized material does not occur and such that
oversize material is completely surrounded by compacted or densified fill. Oversize material
shall not be placed within 10 vertical feet of finish grade or within 2 feet of future utilities or
underground construction.
General Earthwork and Grading Specifications for Rough Grading Page 3
3.3 Import
If importing of fill material is required for grading, proposed import material shall meet the
requirements of the geotechnical consultant. The potential import source shall be given to the
Geotechnical Consultant at least 48 hours (2 working days) before importing begins so that its
suitability can be determined and appropriate tests performed.
4.0 Fill Placement and Compaction
4.1 Fill Layers
Approved fill material shall be placed in areas prepared to receive fill (per Section 3.0) in
near-horizontal layers not exceeding 8 inches in loose thickness. The Geotechnical
Consultant may accept thicker layers if testing indicates the grading procedures can
adequately compact the thicker layers. Each layer shall be spread evenly and mixed
thoroughly to attain relative uniformity of material and moisture throughout.
4.2 Fill Moisture Conditioning
Fill soils shall be watered, dried back, blended, and/or mixed, as necessary to attain a
relatively uniform moisture content at or slightly over optimum. Maximum density and
optimum soil moisture content tests shall be performed in accordance with the American
Society of Testing and Materials (ASTM Test Method D1557).
4.3 Compaction of Fill
After each layer has been moisture-conditioned, mixed, and evenly spread, it shall be
uniformly compacted to not less than 90 percent of maximum dry density (ASTM Test
Method D1557). Compaction equipment shall be adequately sized and be either specifically
designed for soil compaction or of proven reliability to efficiently achieve the specified level of
compaction with uniformity.
4.4 Compaction of Fill Slopes
In addition to normal compaction procedures specified above, compaction of slopes shall be
accomplished by backrolling of slopes with sheepsfoot rollers at increments of 3 to 4 feet in
fill elevation, or by other methods producing satisfactory results acceptable to the
Geotechnical Consultant. Upon completion of grading, relative compaction of the fill, out to
the slope face, shall be at least 90 percent of maximum density per ASTM Test Method D1557.
4.5 Compaction Testing
Field tests for moisture content and relative compaction of the fill soils shall be performed
by the Geotechnical Consultant. Location and frequency of tests shall be at the Consultant's
discretion based on field conditions encountered. Compaction test locations will not
necessarily be selected on a random basis. Test locations shall be selected to verify
adequacy of compaction levels in areas that are judged to be prone to inadequate compaction
(such as close to slope faces and at the fill/bedrock benches).
General Earthwork and Grading Specifications for Rough Grading Page 4
4.6 Frequency of Compaction Testing
Tests shall be taken at intervals not exceeding 2 feet in vertical rise and/or 1,000 cubic yards of
compacted fill soils embankment. In addition, as a guideline, at least one test shall be taken
on slope faces for each 5,000 square feet of slope face and/or each 10 feet of vertical height
of slope. The Contractor shall assure that fill construction is such that the testing schedule
can be accomplished by the Geotechnical Consultant. The Contractor shall stop or slow
down the earthwork construction if these minimum standards are not met.
4.7 Compaction Test Locations
The Geotechnical Consultant shall document the approximate elevation and horizontal
coordinates of each test location. The Contractor shall coordinate with the project surveyor to
assure that sufficient grade stakes are established so that the Geotechnical Consultant can
determine the test locations with sufficient accuracy. At a minimum, two grade stakes within
a horizontal distance of 100 feet and vertically less than
5 feet apart from potential test locations shall be provided.
5.0 Subdrain Installation
Subdrain systems shall be installed in accordance with the approved geotechnical report(s), the
grading plan, and the Standard Details. The Geotechnical Consultant may recommend additional
subdrains and/or changes in subdrain extent, location, grade, or material depending on conditions
encountered during grading. All subdrains shall be surveyed by a land surveyor/civil engineer for line
and grade after installation and prior to burial. Sufficient time should be allowed by the Contractor for
these surveys.
6.0 Excavation
Excavations, as well as over-excavation for remedial purposes, shall be evaluated by the Geotechnical
Consultant during grading. Remedial removal depths shown on geotechnical plans are estimates only.
The actual extent of removal shall be determined by the Geotechnical Consultant based on the field
evaluation of exposed conditions during grading. Where fill-over-cut slopes are to be graded, the cut
portion of the slope shall be made, evaluated, and accepted by the Geotechnical Consultant prior to
placement of materials for construction of the fill portion of the slope, unless otherwise recommended
by the Geotechnical Consultant.
7.0 Trench Backfills
7.1 The Contractor shall follow all OHSA and Cal/OSHA requirements for safety of trench
excavations.
7.2 All bedding and backfill of utility trenches shall be done in accordance with the applicable
provisions of Standard Specifications of Public Works Construction. Bedding material shall
have a Sand Equivalent greater than 30 (SE>30). The bedding shall be placed to 1 foot over
General Earthwork and Grading Specifications for Rough Grading Page 5
General Earthwork and Grading Specifications for Rough Grading Page 6
the top of the conduit and densified by jetting. Backfill shall be placed and densified to a
minimum of 90 percent of maximum from 1 foot above the top of the conduit to the surface.
7.3 The jetting of the bedding around the conduits shall be observed by the Geotechnical
Consultant.
7.4 The Geotechnical Consultant shall test the trench backfill for relative compaction. At least one
test should be made for every 300 feet of trench and 2 feet of fill.
7.5 Lift thickness of trench backfill shall not exceed those allowed in the Standard Specifications
of Public Works Construction unless the Contractor can demonstrate to the Geotechnical
Consultant that the fill lift can be compacted to the minimum relative compaction by his
alternative equipment and method.