HomeMy WebLinkAboutAppendix D - Geotechnical Report (Enclave)
GEOTECHNICAL INVESTIGATION
FOR
CURTIS AVENUE DEVELOPMENT
CURTIS AND CITRUS AVENUES
FONTANA, CA
for
North Fontana Investment Company, LLC
1156 N. Mountain Avenue P.O. Box 670
Upland, CA 91785-0670
January 9, 2024
00-232887-01
Carson 310.684.4854 | Concord 925.243.6662 | Rancho Cucamonga 909.989.1751
Sacramento 916.631.7194 | San Diego 858.609.7138 | San Jose 408.362.4920
January 9, 2024
North Fontana Investment Company, LLC
1156 N. Mountain Avenue P.O. Box 670
Upland, CA 91785-0670
Attention: Stacey Sassaman
Subject: Geotechnical Investigation for
Curtis Avenue Development
Curtis and Citrus Avenues
Fontana, CA
Dear Ms. Sassaman:
In accordance with your request, a geotechnical investigation has been completed for the above referenced project.
The report addresses both engineering geologic and geotechnical conditions. The results of the investigation are
presented in the accompanying report, which includes a description of site conditions, results of our field
exploration, laboratory testing, conclusions, and recommendations.
We appreciate this opportunity to be of continued service to you. If you have any questions regarding this report,
please do not hesitate to contact us at your convenience.
Respectfully submitted,
RMA Group
Ken Dowell, PG|CEG
Project Geologist
CEG 2470
Haitham Dawood, PhD|PE|GE
Engineering Manager
GE 3227
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page i
TABLE OF CONTENTS
PAGE
1.00 INTRODUCTION 1
1.01 Purpose 1
1.02 Scope of the Investigation 1
1.03 Site Location and Description 1
1.04 Current and Past Land Usage 2
1.05 Planned Usage 2
1.06 Investigation Methods 2
2.00 FINDINGS 2
2.01 Geologic Setting 2
2.02 Earth Materials 3
2.03 Expansive Soils 3
2.04 Surface and Groundwater Conditions 3
2.05 Faults 3
2.06 Historic Seismicity 5
2.07 Flooding Potential 6
2.08 Landslides 6
3.00 CONCLUSIONS AND RECOMMENDATIONS 6
3.01 General Conclusion 6
3.02 General Earthwork and Grading 6
3.03 Earthwork Shrinkage and Subsidence 6
3.04 Removals and Overexcavation 6
3.05 Rippability and Rock Disposal 7
3.06 Subdrains 7
3.07 Permanent Fill and Cut Slopes 8
3.08 Faulting 8
3.09 Seismic Design Parameters 8
3.10 Liquefaction and Secondary Earthquake Hazards 9
3.11 Foundations 10
3.12 Foundation Setbacks from Slopes 10
3.13 Slabs on Grade 11
3.14 Miscellaneous Concrete Flatwork 12
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page ii
TABLE OF CONTENTS
(Continued)
PAGE
3.15 Footing Excavation and Slab Preparations 12
3.16 Lateral Load Resistance 13
3.17 Drainage and Moisture Proofing 14
3.18 Cement Type and Corrosion Potential 14
3.19 Temporary Slopes 15
3.20 Utility Trench Backfill 16
3.21 Pavement Sections 17
3.22 Soil Infiltration Testing 18
3.23 Plan Review 19
3.24 Geotechnical Observation and Testing During Rough Grading 19
3.25 Post-Grading Geotechnical Observation and Testing 19
4.00 CLOSURE 19
FIGURES AND TABLES
Figure 1 Site Location and Earthquake Fault Zone Map
Figure 2 Regional Geologic Map
Figure 3 Exploration Map
Figure 4 Regional Depth to Groundwater Map
Figure 5 Regional Groundwater Elevation Map
Figure 6 Regional Geologic Cross Section
Figure 7 Rialto-Colton Groundwater Subbasin Map
Figure 8 Regional Fault Map
Table 1 Notable Faults within 100 Km
Table 2 Historical Strong Earthquakes
APPENDICES
Appendix A Field Investigation A1
Appendix B Laboratory Tests B1
Appendix C General Earthwork and Grading Specifications C1
Appendix D References D1
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 1
1.00 INTRODUCTION
1.01 Purpose
A geotechnical investigation has been completed for proposed construction of a residential development. The
purpose of the investigation was to summarize geotechnical and geologic conditions at the site, to assess their
potential impact on the proposed development, and to develop geotechnical and engineering geologic design
parameters.
1.02 Scope of the Investigation
The general scope of this investigation included the following:
• Review of published and unpublished geologic, seismic, groundwater and geotechnical literature.
• Review of a prior geotechnical investigation completed for the site prepared by Leighton Consulting Inc. and
dated November 9, 2005.
• Examination of aerial photographs.
• Contacting of underground service alert to locate onsite utility lines.
• Logging, sampling and backfilling of 6 exploratory borings and 2 infiltration test borings drilled with a truck
mounted hollow stem auger drill rig.
• Performance of 2 infiltration tests in the area of the proposed storm water basin. The tests were done in
conformance with the San Bernardino Technical Guidance Document for Water Quality Management
Plans Manual, specifically the borehole test method.
• Laboratory testing of representative soil samples.
• Geotechnical evaluation of the compiled data.
• Preparation of this report presenting our findings, conclusions and recommendations.
Our scope of work did not include a preliminary site assessment for the potential of hazardous materials onsite.
1.03 Site Location and Description
The approximately 12 acre site is located in northern portion area of the City of Fontana, California. Its
approximate location is shown on Site Location Map (Figure 1). The site is located on the north side of Curtis
Avenue and about 500 feet west of Citrus Avenue. Existing residential properties are located to the north, east
and west of the site.
At the time of our investigation the site consisted of a vacant field covered with native grasses and weeds. There
were no man-made improvements on the property besides a modular trailer in the southwest corner of the site and
a chain link fence along the south side of the site. A few fire breaks had been cut through the brush that covered
the property.
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 2
Topographically, the property is a nearly planar surface that slopes to the southwest at an overall gradient of
about 3-4 percent to the southwest. Elevation of the site ranges from about 1,565 to 1,585 feet above sea level.
1.04 Current and Past Land Usage
The site is currently vacant. Based upon a review of historic aerial photographs the site has not previously been
developed and no prior usage is visible in the aerials as far back as 1938.
1.05 Planned Usage
It is our understanding that the proposed construction will consist of a residential development including parking
and other surface improvements and amenities.
Our investigation was performed prior to the preparation of grading or foundation plans. To aid in preparation of
this report, we utilized the following assumptions:
• Maximum foundation loads of 2 to 3 kips per linear foot for continuous footings and 60 kips for isolated
spread footings.
• Cuts and fills will be less than 5 feet.
1.06 Investigation Methods
Our investigation consisted of office research, field exploration, laboratory testing, review of the compiled data, and
preparation of this report. It has been performed in a manner consistent with generally accepted engineering and
geologic principles and practices, and has incorporated applicable requirements of California Building Code.
Definitions of technical terms and symbols used in this report include those of the ASTM International, the California
Building Code, and commonly used geologic nomenclature.
Technical supporting data are presented in the attached appendices. Appendix A presents a description of the
methods and equipment used in performing the field exploration and logs of our subsurface exploration. Appendix
B presents a description of our laboratory testing and the test results. Standard grading specifications and
references are presented in Appendices C and D, respectively.
2.00 FINDINGS
2.01 Geologic Setting
The site is located in northern Fontana on a broad, coalescing alluvial fan that emanates from the San Gabriel
Mountains and the Lytle Creek drainage to the north. These sediments fill the northern portion of a deep
structural depression known as the upper Santa Ana River Valley. According to Fife and others (1976), the alluvial
deposits beneath the site are approximately 500 to 600 feet thick and rest on crystalline basement bedrock.
The upper Santa Ana River Valley is bordered by the San Gabriel Mountains and the active Cucamonga fault to the
north, and the Puente Hills and active Chino fault to the west. To the south are the Jurupa Mountains and other
resistant granitic and metamorphic hills. The eastern boundary of the valley is the San Bernardino Mountains and
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 3
the active San Andreas fault.
The general geologic setting of the site is illustrated on the accompanying Regional Geologic Map (Figure 2).
2.02 Earth Materials
Regional geologic maps and field investigation revealed that the site is underlain by Holocene age alluvial fan
deposits. The alluvium, as encountered in our borings, consists of surficial layer of loose silty sand that extends for
the ground surface to depths of 1 to 3 feet and rests on poorly graded gravelly sand with silt.
The upper silty sand encountered in our borings, and based upon other investigations completed by this office in the
surrounding area, contained an estimated 5 to 25 percent gravel and approximately 0 to 5 percent cobbles.
Boulders were not encountered within the silty sand in our borings, although the possibility of boulders being
present within the silty sand elsewhere in the site cannot be ruled out. The lower poorly graded sand with gravel
unit encountered in our borings contained an estimated 15 to 40 percent gravel. Based on our prior experience and
a review of the trench logs from the Leighton report we would expect up to 5 to 10 percent cobbles and possibly a 2
to 3 percent boulders in the lower sand layer. We would also expect boulder sizes to range from approximately 12
to 26 inches in maximum dimension.
The subsurface soils encountered in the exploratory borings drilled at the site are described in greater detail on the
logs contained in Appendix A. Locations of exploratory borings are presented on Figure 3.
2.03 Expansive Soils
Expansion testing performed in accordance with ASTM D4829 indicates that earth materials underlying the site have
an expansion classification of very low.
2.04 Surface and Groundwater Conditions
No areas of ponding or standing water were present at the time of our study. Further, no springs or areas of natural
seepage were found.
Groundwater was not encountered during our subsurface exploration which extended to a maximum depth of 25.5
feet. According to Fife (1974) the depth to groundwater beneath the site was between 300 to 600 feet in 1960
(Figure 4). The map prepared by Fife also shows two subsurface groundwater barriers crossing very near the
site. They are the northeast-southwest trending Barrier J, is also mapped through the site, and the other being
the northwest-southeast trending Colton-Rialto fault. Current depth to groundwater is expected to be similar,
but nearby water well data is not available to confirm the present depth to groundwater. The Colton-Rialto fault
is considered to be the western boundary of the Colton-Rialto Groundwater Subbasin. Depth to groundwater
east of the fault is typically shallower than on the west side. Further discussion of these two features is included
in Section 2.05 Faults.
2.05 Faults
The site is not located within the boundaries of an Earthquake Fault Zone for fault-rupture hazard as defined by the
Alquist-Priolo Earthquake Fault Zoning Act. The nearest Earthquake Fault Zone is located about 2 miles to the
northwest along the Cucamonga fault (see Figure 1). This is also the nearest fault with surface expression.
Two concealed faults are mapped near or through the site, “Barrier J” and the Rialto-Colton fault. Both faults are
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 4
mapped as concealed and are not defined as surface features by the State of California.
“Barrier J”, was mapped through the site by Dutcher and Garrett (1963) during a groundwater study of the San
Bernardino area (Figure 5) and by Woolfenden and Kadhim (1997). Maps contained in the report show “Barrier J” to
be approximately 4.5 miles (7 kilometers) long. The Dutcher and Garrett report also contains a geologic cross section
(C-C’) that was drawn in a north-south direction along Sierra Avenue located to the east side of the site. The cross
section shows that “Barrier J” offsets Tertiary age continental deposits, but is overlain by about 1 mile of unfaulted
younger and older alluvium (see Figure 6). The location of the cross section is shown about 1 mile east of the site.
The location of the site is projected on the cross section and therefore does not show the location of “Barrier J”
crossing the site. The cross section is included to illustrate that “Barrier J” offsets the Tertiary age deposits and is
overlain by nearly a mile of unfaulted sediments in the vicinity of the site and that there is not surface expression of
the feature at or near the site.
Hadley and Combs (1974) performed a micro-seismicity study of the Fontana-San Bernardino region in the early
1970s and recorded numerous small earthquakes that generally aligned with “Barrier J”. The magnitudes of these
earthquakes typically ranged from 1 to 3 and indicated a left-lateral strike-slip sense of motion with a possible dip-
slip component. The California Department of Water Resources (1970) reported that “Barrier J” is a normal fault
that has displaced the base of fresh groundwater upward about 100 feet. The Department of Water Resources also
reported that the formation of “Barrier J” was likely caused by uplift of the San Gabriel Mountains, that the fault has
no surface expression, and that groundwater cascades over the barrier. A gravity study performed by Anderson and
others (2000) did not identify gravity anomalies indicative of faulting along “Barrier J”.
The California Division of Mines and Geology (Burnett and Hart, 1994) evaluated “Barrier J” with respect to possible
inclusion in a State of California Earthquake Fault Zone for fault rupture hazards. They noted the following: 1)
Dutcher and Garrett (1963) inferred a concealed fault in older alluvium, 2) the barrier is inferred to offset the water
table about 200 feet (northwest side up), 3) microseismicity aligns with “Barrier J” suggesting to Hadley and Combs
(1974) it might be a fault related to the Cucamonga fault system, 4) small earthquakes reported by Magistrale and
Sanders (1994) align with “Barrier J”, and 5) the barrier is shown on an early map by Morton (1974) but not on later
maps by Morton and Matti (1987 and 1991). Burnett and Hart found no evidence to suggest that “Barrier J” is
surface feature and recommended that “Barrier J” not be included in an Alquist-Priolo Earthquake Fault Zone.
We reviewed several different ages of aerials photographs (both stereo and non-stereo) and did not observe any
lineaments along the mapped trace of “Barrier J.” and the Rialto-Colton fault near the site. In addition, we did not
observe any topographic or vegetation lineaments in the field along the mapped trace of “Barrier J” and the Rialto-
Colton fault. Consequently, we agree with the findings of the California Division of Mines and Geology (now the
California Geological Survey) that “Barrier J” is not a defined surface feature.
The Rialto-Colton fault is located on most maps to be just to the southwest of the site. Recent mapping by
Woolfenden and Kadhim (1997) indicate that the fault terminates at the intersection of Barrier J, just southwest of
the site and extends to the southeast. More recent mapping by Brandt (2022) indicates the termination of the
Rialto-Colton fault about 100-150 feet south of the site and does not include the Barrier J feature in his mapping
(Figure 7). As with “Barrier J” in the north end of the Rialto-Colton basin, the Rialto-Colton fault is described as a
groundwater barrier without surface expression. Woolfenden and Kadhim (1997) describe the Rialto-Colton fault as
“subparallel to the San Jacinto Fault and trends southeastward from Barrier J to the Badlands. Vertical
displacement along the Rialto-Colton Fault is reflected by the shallower depths to the basement complex in the
Chino basin in comparison with the Rialto-Colton basin. The Rialto-Colton Fault probably is an abandoned trace
of the San Jacinto Fault”. They also state that the groundwater level across the fault varies about 400 feet on either
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 5
side of the northern portion of the fault. The Fife (1974) groundwater contour map indicates groundwater in the
vicinity of the site varies from east side of the fault at about 300 feet below the ground surface to about 600 feet
west of the fault. Where the Rialto-Colton fault is shown in cross section in Dutcher and Garrett, it is covered by a
several hundred feet of alluvial soil. The Rialto-Colton is also not recognized as a defined surface feature.
To further evaluate the possibility of surface fault rupture along “Barrier J” in the area of the site, we considered
subsurface fault rupture, magnitude and displacement using data developed by Wells and Coppersmith (1994) and
propagation of fault rupture through overlying soils based on experiments performed by Anastasopuolos and others
(2007). Wells and Coppersmith relate subsurface fault rupture length to earthquake magnitude. They indicate that
a fault with a length of 7 km (the total length of “Barrier J” according to Dutcher and Garrett) corresponds to a 5.6
magnitude earthquake. They also indicate subsurface displacement associated with a 5.6 magnitude earthquake is
approximately 0.025 meters (0.08 feet). Anastasopoulos and others report that subsurface rupture along a normal
fault propagating through sandy soils is not likely to reach the ground surface if the ratio of base fault offset to soil
thickness (h/H) is less than or equal to 0.075%. Using a displacement of 0.08 feet and a soil thickness of 280 feet,
h/H = 0.029%. Since this value is less than 0.075%, we conclude that possible future surface ground rupture
associated with seismic along “Barrier J” is not likely to occur within the site. Based upon the reviewed geologic
mapping the Rialto-Colton fault terminates either at Barrier J or south of the site. Since the site lies north of the
mapped terminus of the fault, we conclude that possible future surface ground rupture associated with seismic
along Rialto-Colton fault is not likely to occur within the site.
Barrier J and the Rialto-Colton faults are both mapped as concealed features and based upon the discussed research
above both are buried by several hundred feet of alluvial soil. The locations of these features have been inferred and
are based upon differences in measurements of well data across the features and by geophysical data. The exact
locations of these features are unknown. Based upon the lack of surface expression and limited paleoseismicity that
would indicate the more specific location of these features, it is our opinion that the possibility of surface rupture at
the site is minimal.
The accompanying Figures 1, 2 4, 5, 7 and 8 illustrate the location of the site with respect to major faults in the
region. The distance to notable faults within 100 kilometers of the site is presented on Table 1.
The accompanying Regional Fault Map (Figure 6) illustrates the location of the site with respect to major faults
in the region. The distance to notable faults within 100 kilometers of the site is presented on Table 1.
2.06 Historic Seismicity
The site is located in a seismically active area, as is the case throughout Southern California. At this time it is not
possible to state with certainty when and where future large magnitude earthquakes will occur, or what the
magnitude and intensity of these events will be. However, estimates can be made based on the tectonic data
and seismic history. The seismic setting of the site has been evaluated by review of historic seismicity, by
deterministic methods, by probabilistic methods and by code procedures.
The nearest historic strong earthquake was epicentered within about 11 miles northeast of the site. It was the
6.4 magnitude Manix Earthquake that occurred in 1899. It occurred prior to the development of seismic
monitoring networks, thus their locations and magnitudes are only approximate. Historic strong earthquakes in
the southern California region are summarized on Table 2.
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 6
2.07 Flooding Potential and Wind Erosion
According to Federal Emergency Management Agency (2008), the site is located within Flood Zone X, which is
defined as an “area determined to be outside the 0.2% annual chance floodplain.”
The site is located near the mouth of Cajon Pass, which carries strong “Santa Ana” winds in the fall and during other
times of the year. These winds can cause significant surficial erosion of soils that are not protected by vegetation,
concrete or asphalt.
2.08 Landslides
Due to the low gradient of the site and surrounding area, Landsliding is not a hazard at this property.
3.00 CONCLUSIONS AND RECOMMENDATIONS
3.01 General Conclusion
Based on specific data and information contained in this report, our understanding of the project and our general
experience in engineering geology and geotechnical engineering, it is our professional judgment that the proposed
development is geologically and geotechnically feasible. This is provided that the recommendations presented
below are fully implemented during design, grading and construction.
3.02 General Earthwork and Grading
All grading should be performed in accordance with the General Earthwork and Grading Specifications outlined in
Appendix C, unless specifically revised or amended below. Recommendations contained in Appendix C are general
specifications for typical grading projects and may not be entirely applicable to this project.
It is also recommended that all earthwork and grading be performed in accordance with Appendix J of the 2022
California Building Code and all applicable governmental agency requirements. In the event of conflicts between this
report and Appendix J, this report shall govern.
3.03 Earthwork Shrinkage and Subsidence
Shrinkage is the decrease in volume of soil upon removal and recompaction expressed as a percentage of the
original in-place volume. Subsidence occurs as natural ground is densified to receive fill. These factors account for
changes in earth volumes that will occur during grading. Our estimates are as follows:
• Shrinkage factor = 7% - 12% for soil removed and replaced as compacted fill.
• Subsidence factor = 0.15 foot.
The degree to which fill soils are compacted and variations in the insitu density of existing soils will influence earth
volume changes. Consequently, some adjustments in grades near the completion of grading could be required to
balance the earthwork.
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 7
3.04 Removals and Overexcavation
All vegetation, trash and debris should be cleared from the grading area and removed from the site. Prior to
placement of compacted fills, all non-engineered fills and loose, porous, or compressible soils will need to be
removed down to competent ground. Removal and requirements will also apply to cut areas, if the depth of cut is
not sufficient to reach competent ground. Removed and/or overexcavated soils may be moisture-conditioned and
recompacted as engineered fill, except for soils containing detrimental amounts of organic material. Estimated
depths of removals are as follows:
• Loose, porous and compressible native soils were encountered to depths of about 1 to 3 feet below
existing grades. The average depth of removal of these soils is expected to be 2 feet with some local
areas extending to 5 feet below the existing ground surface.
• It is expected that competent native soils will be encountered in cuts deeper than approximately 2 to 5
feet below existing grade. Provided competent soils are exposed, these cut surfaces should be scarified
to a minimum depth of 12 inches, moisture conditioned and compacted to at least 90 percent of the
maximum dry density, provided that footing overexcavation requirements are met.
In addition to the above requirements, overexcavation will also need to meet the following criteria for the building
pads, concrete flatwork and pavement areas:
• All footing areas, both continuous and spread, shall be undercut, moistened, and compacted as necessary
to produce soils compacted to a minimum of 90% relative compaction to a depth equal to the width of the
footing below the bottom of the footing or to a depth of 3 feet below the bottom of the footing, whichever
is less. Footing areas shall be defined as the area extending from the edge of the footing for a distance of 5
feet.
• All floor slabs, and concrete flatwork shall be underlain by a minimum of 12 inches of soil compacted to a
minimum of 90% relative compaction.
• All paved areas shall be underlain by a minimum of 12 inches of soil compacted to a minimum of 90%
relative compaction.
The exposed soils beneath all overexcavation should be scarified an additional 12 inches, moisture conditioned
and compacted to a minimum of 90% relative compaction.
The above recommendations are based on the assumption that soils encountered during field exploration are
representative of soils throughout the site. However, there can be unforeseen and unanticipated variations in
soils between points of subsurface exploration. Hence, overexcavation depths must be verified, and adjusted if
necessary, at the time of grading. The overexcavated materials may be moisture-conditioned and re-compacted as
engineered fill.
3.05 Rippability and Rock Disposal
Our exploratory trenches were advanced without difficulty. Accordingly we expect that all earth materials will be
rippable with conventional heavy duty grading equipment.
Based on the result of our subsurface exploration, it is expected that oversized materials (greater than 12 inches in
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 8
maximum dimension) will be generated from excavations made into alluvial soils underlying the site. Based upon
our past experience in the area, oversize materials encountered during our subsurface investigation ranged from
about 12 to 26 inches in maximum dimension and are estimated to be about 1% to 4% of the total soil profile.
Our guidelines for rock disposal are presented in Appendix C. Implementation of our guidelines will require
continuous testing and observation by a member of our staff. Oversized materials should not be placed within 10
feet of finish grade without the prior approval of the geotechnical consultant.
3.06 Subdrains
Groundwater and surface water were not encountered during the course of our investigation, the proposed
construction will not fill any large canyons or drainage features and the underlying soils are fairly permeable.
Consequently, installation of canyon subdrains is not expected to be necessary.
3.07 Permanent Fill and Cut Slopes
Fill and cut slopes, if necessary, should be constructed at inclinations of 2 to 1 (horizontal to vertical, H:V) or flatter.
3.08 Faulting
Refer to Section 2.05 for discussion of area faults.
3.09 Seismic Design Parameters
The potential damaging effects of regional earthquake activity must be considered in the design of structures.
Mapped Design Parameters
Mapped seismic design parameters have been developed in accordance with Section 1613A of the 2022
California Building Code (CBC) using the online ACE 7 Hazard Tool (ASCE 7-16 Standard), a site location based on
latitude and longitude, and site characterization as Site Class D based on our preliminary geotechnical investigation.
The parameters generated for the subject site are presented below:
2022 California Building Code Seismic Parameters
Parameter Value
Site Location Latitude = 34.14408 degrees
Longitude = -117.45647 degrees
Site Class Site Class = D
Soil Profile Name = Stiff soil
Mapped Spectral Accelerations
(Site Class B)
Ss (0.2- second period) = 2.125g
S1 (1-second period) = 0.691g
Site Coefficients
(Site Class D)
Fa = 1.0
Fv = 1.7
Risk-Targeted Maximum Considered Earthquake
Spectral Accelerations (Site Class D)
SMS (short, 0.2- second period) = 2.125g
SM1 (1-second period) = 1.762g*
Risk-Targeted Design Earthquake
Spectral Accelerations (Site Class D)
SDS (short, 0.2- second period) = 1.417g
SD1 (1-second period) = 1.175g*
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 9
*The values for SM1 and SD1 in the table above are calculated based upon Section 11.4.8
Exception 3 as revised by ASCE 7-16 Supplement 3 where SM1 is determined by Equation
11.4-2 and is increased by 50%.
The above table shows that the mapped spectral response acceleration parameter a 0.2-second period (SDS) >
0.5g. Therefore, for the Seismic Design Category is D for all Risk Categories (CBC Section 1613.2.5).
Consequently, as required for Seismic Design Categories D through F by CBC Section 1803A.5.12, lateral
pressures for earthquake ground motions, liquefaction and soil strength loss have been evaluated (see Sections
3.10 and 3.16).
Peak earthquake ground acceleration adjusted for site class effects (PGAM) has been determine in accordance
with ASCE 7-16 Section 11.8.3 as follows: PGAM = FPGA x PGA = 1.1 x 0.866g = 0.953g.
3.10 Liquefaction and Secondary Earthquake Hazards
Potential secondary seismic hazards that can affect land development projects include liquefaction, tsunamis,
seiches, seismically induced settlement, seismically induced flooding and seismically induced landsliding.
Liquefaction
Liquefaction is a phenomenon where earthquake-induced ground motions increase the pore pressure in saturated,
sand-like soils until it is equal to the confining, overburden pressure. When this occurs, the soil can completely lose
its shear strength and enter a liquefied state. The possibility of liquefaction is dependent upon grain size, relative
density, confining pressure, saturation of the soils, and intensity and duration of ground motion. In order for
liquefaction to occur, three criteria must be met: underlying loose, sand-like soils, a groundwater depth of less than
about 50 feet, and a potential for seismic shaking from nearby large-magnitude earthquake.
As ground water table was not encountered and is mapped at least 300 ft below the ground surface (Section 2.04),
the ground water table is expected to be at least 200 or deeper at the site, liquefaction at the site is unlikely to occur
and hence it is not a design concern.
Tsunamis and Seiches
Tsunamis are sea waves that are generated in response to large-magnitude earthquakes. When these waves
reach shorelines, they sometimes produce coastal flooding. Seiches are the oscillation of large bodies of
standing water, such as lakes, that can occur in response to ground shaking. Tsunamis and seiches do not pose
hazards due to the inland location of the site and lack of nearby bodies of standing water.
Seismically Induced Settlement
Seismically induced settlement occurs most frequently in areas underlain by loose, granular sediments. Damage as
a result of seismically induced settlement is most dramatic when differential settlement occurs in areas with large
variations in the thickness of underlying sediments. Settlement caused by ground shaking is often non-uniformly
distributed, which can result in differential settlement.
Because loose near surface soils will be recompacted during site grading and deeper soils are denser and
essentially uniform in thickness, the potential for significant seismically induced settlement to occur is judged to
be unlikely.
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 10
Seismically Induced Flooding
There are no up gradient water reservoirs or dams located in close proximity of the site. Consequently seismically
induced flooding at the site is unlikely.
Seismically Induced Landsliding
Due to the low gradient of the site, the potential for seismically induced landsliding is nil. This assumes that any
slopes created during development of the school site will be properly designed and constructed. It should be noted
that the California Geological Survey has not yet prepared a Seismic Hazard Zone Map of potential earthquake-
induced landslide hazards for the quadrangle in which the site is located.
3.11 Foundations
Isolated spread footings and/or continuous wall footings are recommended to support the proposed structures. If
the recommendations in the section on grading are followed and footings are established in firm native soils or
compacted fill materials, footings may be designed using the following allowable soil bearing values:
• Continuous Wall Footings:
Footings having a minimum width of 12 inches and a minimum depth of 12 inches below the lowest
adjacent grade have allowable bearing capacity of 2,000 pounds per square foot (psf). This value may
be increased by 10% for each additional foot of width and/or depth to a maximum value of 3,000 psf.
• Isolated Spread Footings:
Footings having a minimum width of 12 inches and a minimum depth of 12 inches below the lowest
adjacent grade have allowable bearing capacity of 2,000 psf. This value may be increased by 10% for
each additional foot of width or depth to a maximum value of 3,000 psf.
• Retaining Wall Footings:
Footings for retaining walls should be founded a minimum depth of 12 inches and have a minimum
width of 12 inches. Footings may be designed using the allowable bearing capacity and lateral
resistance values recommended for building footings. However, when calculating passive resistance,
the upper 6 inches of the footings should be ignored in areas where the footings will not be covered
with concrete flatwork. This value may also be increased by 10% for each additional foot of width or
depth to a maximum value of 3,000 psf. Reinforcement should be provided for structural considerations
as determined by the design engineer.
The above bearing capacities represent an allowable net increase in soil pressure over existing soil pressure and may
be increased by one-third for short-term wind or seismic loads. The maximum expected settlement of footings
designed with the recommended allowable bearing capacity is expected to be on the order of ½ inch with
differential settlement on the order of ¼ inch.
Soils at the site are generally granular, non-plastic and have a very low expansion potential. Therefore,
reinforcement of footings to mitigate expansive soil is not required. However, in view of the seismic setting, a
nominal reinforcement consisting of one #4 bar placed within 3 inches of the top of footings and another placed
within 3 inches of the bottom of footings is recommended. The structural engineer may require heavier
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 11
reinforcement.
3.12 Foundation Setbacks from Slopes
Setbacks for footings adjacent to slopes should conform to the requirements of the California Building Code.
Specifically, footings should maintain a horizontal distance or setback between any adjacent slope face and the
bottom outer edge of the footing.
For slopes descending away from the foundation, the horizontal distance may be calculated by using h/3, where h is
the height of the slope. The horizontal setback should not be less than 5 feet, nor need not be greater than 40 feet
per the California Building Code. Where structures encroach within the zone of h/3 from the top of the slope the
setback may be maintained by deepening the foundations. Flatwork and utilities within the zone of h/3 from the
top of slope may be subject to lateral distortion caused by gradual downslope creep. Walls, fences and landscaping
improvements constructed at the top of descending slopes should be designed with consideration of the potential
for gradual downslope creep.
For ascending slopes, the horizontal setback required may be calculated by using h/2 where h is the height of the
slope. The horizontal setback need not be greater than 15 feet per the California Building Code.
3.13 Slabs on Grade
We recommend the use of unreinforced slabs on grade for structures. These floor slabs should have a minimum
thickness of 4 inches and should be divided into squares or rectangles using weakened plane joints (contraction
joints), each with maximum dimensions not exceeding 15 feet. Contraction joints should be made in accordance
with American Concrete Institute (ACI) guidelines. If weakened plane joints are not used, then the slabs shall be
reinforced with at a minimum 6x6-10/10 welded wire fabric placed at mid-height of the slab. The project structural
engineer may require additional reinforcement.
If heavy concentrated or moving loads are anticipated, slabs should be designed using a modulus of subgrade
reaction (k) of 150psi/in when soils are prepared in conformance with the grading recommendations contained
within the report.
Special care should be taken on floors slabs to be covered with thin-set tile or other inflexible coverings. These
areas may be reinforced with 6x6-10/10 welded wire fabric placed at mid-height of the slab, to mitigate drying
shrinkage cracks. Alternatively, inflexible flooring may be installed with unbonded fabric or liners to prevent
reflection of slab cracks through the flooring.
A moisture vapor retarder/barrier is recommended beneath all slabs-on-grade that will be covered by moisture-
sensitive flooring materials such as vinyl, linoleum, wood, carpet, rubber, rubber-backed carpet, tile,
impermeable floor coatings, adhesives, or where moisture-sensitive equipment, products, or environments will
exist. We recommend that design and construction of the vapor retarder or barrier conform to Section 1805 of
the 2022 California Building Code (CBC) and pertinent sections of American Concrete Institute (ACI) guidance
documents 302.1R-04, 302.2R-06 and 360R-10.
The moisture vapor retarder/barrier should consist of a minimum 10 mils thick polyethylene with a maximum
perm rating of 0.3 in accordance with ASTM E 1745. Seams in the moisture vapor retarder/barrier should be
overlapped no less than 6 inches or in accordance with the manufacturer’s recommendations. Joints and
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 12
penetrations should be sealed with the manufacturer’s recommended adhesives, pressure-sensitive tape, or
both. The contractor must avoid damaging or puncturing the vapor retarder/barrier and repair any punctures
with additional polyethylene properly lapped and sealed.
ACI guidelines allow for the placement of moisture vapor retarder/barriers either directly beneath floor slabs or
below an intermediate granular soil layer.
Placing the moisture retarder/barrier directly beneath the floor slab will provide improved curing of the slab
bottom and will eliminate potential problems caused by water being trapped in a granular fill layer. Concrete
slabs poured directly on a vapor retarder/barrier can experience shrinkage cracking and curling due to
differential rates of curing through the thickness of the slab. Therefore, for concrete placed directly on the vapor
retarded, we recommend a maximum water cement ratio of 0.45 and the use of water-reducing admixtures to
increase workability and decrease bleeding.
If granular soil is placed over the vapor retarder/barrier, we recommend that the layer be at least 2 inches thick
in accordance with traditional practice in southern California. Granular fill should consist of clean fine graded
materials with 10 to 30% passing the No. 100 sieve and free from clay or silt. The granular layer should be
uniformly compacted and trimmed to provide the full design thickness of the proposed slab. The granular fill
layer should not be left exposed to rain or other sources of water such as wet-grinding, power washing, pipe
leaks or other processes, and should be dry at the time of concrete placement. Granular fill layers that become
saturated should be removed and replaced prior to concrete placement.
An additional layer of sand may be placed beneath the vapor retarder/barrier at the developer’s discretion to
minimize the potential of the retarder/barrier being punctured by underlying soils.
3.14 Miscellaneous Concrete Flatwork
Miscellaneous concrete flatwork and walkways may be designed with a minimum thickness of 4 inches. Large
slabs should be reinforced with a minimum of 6x6-10/10 welded wire mesh placed at mid-height in the slab.
Control joints should be constructed to create squares or rectangles with a maximum spacing of 15 feet.
Walkways may be constructed without reinforcement. Walkways should be separated from foundations with a
thick expansion joint filler. Control joints should be constructed into non-reinforced walkways at a maximum of
5 feet spacing.
The subgrade soils beneath all miscellaneous concrete flatwork should be compacted to a minimum of 90 percent
relative compaction for a minimum depth of 12 inches. The geotechnical engineer should monitor the compaction
of the subgrade soils and perform testing to verify that proper compaction has been obtained.
3.15 Footing Excavation and Slab Preparations
All footing excavations should be observed by the geotechnical consultant to verify that they have been excavated
into competent soils. The foundation excavations should be observed prior to the placement of forms,
reinforcement steel, or concrete. These excavations should be evenly trimmed and level. Prior to concrete
placement, any loose or soft soils should be removed. Excavated soils should not be placed on slab or footing areas
unless properly compacted.
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 13
Prior to the placement of the moisture barrier and sand, the subgrade soils underlying the slab should be observed
by the geotechnical consultant to verify that all under-slab utility trenches have been properly backfilled and
compacted, that no loose or soft soils are present, and that the slab subgrade has been properly compacted to a
minimum of 90 percent relative compaction within the upper 12 inches.
Footings may experience and overall loss in bearing capacity or an increased potential to settle where located in
close proximity to existing or future utility trenches. Furthermore, stresses imposed by the footings on the utility
lines may cause cracking, collapse and/or a loss of serviceability. To reduce this risk, footings should extend below a
1:1 plane projected upward from the closest bottom of the trench.
Slabs on grade and walkways should be brought to a minimum of 2% and a maximum of 6% above their optimum
moisture content for a depth of 18 inches prior to the placement of concrete. The geotechnical consultant should
perform insitu moisture tests to verify that the appropriate moisture content has been achieved a maximum of 24
hours prior to the placement of concrete or moisture barriers.
3.16 Lateral Load Resistance
Lateral loads may be resisted by soil friction and the passive resistance of the soil. The following parameters are
recommended.
• Passive Earth Pressure = 500 pcf (equivalent fluid weight). An appropriate factor of safety should be
applied by the design engineer.
Coefficient of Friction (soil to footing) = 0.45
• Retaining structures should be designed to resist the following lateral active earth pressures:
Surface Slope of
Retained Materials
(Horizontal:Vertical)
Equivalent
Fluid Weight
(pcf)
Level 34
5:1 35
4:1 36
3:1 39
2:1 47
These active earth pressures are only applicable if the retained earth is allowed to strain sufficiently to
achieve the active state. The required minimum horizontal strain to achieve the active state is
approximately 0.0025H. Retaining structures should be designed to resist an at-rest lateral earth
pressure if this horizontal strain cannot be achieved.
• At-rest Lateral Earth Pressure = 54 pcf (equivalent fluid weight)
The Mononobe-Okabe method is commonly utilized for determining seismically induced active and passive
lateral earth pressures and is based on the limit equilibrium Coulomb theory for static stress conditions. This
method entails three fundamental assumptions (e.g., Seed and Whitman, 1970): Wall movement is sufficient to
ensure either active or passive conditions, the driving soil wedge inducing the lateral earth pressures is formed
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 14
by a planar failure surface starting at the heel of the wall and extending to the free surface of the backfill, and
the driving soil wedge and the retaining structure act as rigid bodies, and therefore, experiences uniform
accelerations throughout the respective bodies (U.S. Army Corps of Engineers, 2003, Engineering and Design -
Stability Analysis of Concrete Structures).
• Seismic Lateral Earth Pressure = 30 pcf (equivalent fluid weight).
The seismic lateral earth pressure given above is an inverted triangle, and the resultant of this pressure is an
increment of force which should be applied to the back of the wall in the upper 1/3 of the wall height.
Per CBC Section 1803.5.12 dynamic seismic lateral earth pressures shall be applied to foundation walls and retaining
walls supporting more than 6 feet of backfill. Dynamic seismic lateral earth pressures may also be applied to shorter
walls at the discretion of the structural engineer.
3.17 Drainage and Moisture Proofing
Surface drainage should be directed away from the proposed structures into suitable drainage devices. Neither
excess irrigation nor rainwater should be allowed to collect or pond against foundations. Surface waters should be
diverted away from the tops of slopes and prevented from draining over the top of slopes and down the slope face.
3.18 Cement Type and Corrosion Potential
Soluble sulfate tests indicate that concrete at the subject site will have a negligible exposure to water-soluble sulfate
in the soil. Our recommendations for concrete exposed to sulfate-containing soils are presented in the table below.
Recommendations for Concrete exposed to Sulfate-containing Soils
Sulfate
Exposure
Water Soluble
Sulfate (SO4)
in Soil
(% by Weight)
Sulfate (SO4)
in Water
(ppm)
Cement
Type
(ASTM C150)
Maximum
Water-Cement
Ratio
(by Weight)
Minimum
Compressive
Strength
(psi)
Negligible 0.00 - 0.10 0-150 -- -- 2,500
Moderate 0.10 - 0.20 150-1,500 II 0.50 4,000
Severe 0.20 - 2.00 1,500-
10,000 V 0.45 4,500
Very Severe Over 2.00 Over 10,000 V plus pozzolan
or slag 0.45 4,500
Use of alternate combinations of cementitious materials may be permitted if the combinations meet design
recommendations contained in American Concrete Institute guideline ACI 318-11.
The soils were also tested for soil reactivity (pH), electrical resistivity (ohm-cm) and chloride content. The test results
indicate that the on-site soils have a soil reactivity of 7.5, an electrical resistivity of 8,000 ohm-cm, and a chloride
content of 24 ppm. Note that:
• A neutral or non-corrosive soil has a pH value ranging from 5.5 to 8.4.
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 15
• Generally, soils that could be considered moderately corrosive to ferrous metals have resistivity values of about
3,000 ohm-cm to 10,000 ohm-cm. Soils with resistivity values less than 3,000 ohm-cm can be considered
corrosive and soils with resistivity values less than 1,000 ohm-cm can be considered extremely corrosive.
• Chloride contents of approximately 500 ppm or greater are generally considered corrosive.
Based on our preliminary analysis, it appears that the underlying onsite soils are moderately corrosive to ferrous
metals. Protection of buried pipes utilizing coatings on all underground pipes; clean backfills and a cathodic
protection system can be effective in controlling corrosion. As RMA Group, Inc. does not practice corrosion
engineering, a qualified corrosion engineer may be consulted to further assess the corrosive properties of the soil.
3.19 Temporary Slopes
Excavation of utility trenches will require either temporary sloped excavations or shoring. Temporary
excavations in existing alluvial soils may be safely made at an inclination of 1:1 or flatter. If vertical sidewalls are
required in excavations greater than 5 feet in depth, the use of cantilevered or braced shoring is recommended.
Excavations less than 5 feet in depth may be constructed with vertical sidewalls without shoring or shielding.
Our recommendations for lateral earth pressures to be used in the design of cantilevered and/or braced shoring
are presented below. These values incorporate a uniform lateral pressure of 72 psf to provide for the normal
construction loads imposed by vehicles, equipment, materials, and workmen on the surface adjacent to the
trench excavation. However, if vehicles, equipment, materials, etc., are kept a minimum distance equal to the
height of the excavation away from the edge of the excavation, this surcharge load need not be applied.
SHORING DESIGN: LATERAL SHORING PRESSURES
BRACED SHEETING
H
CANTILEVERED SHEETING
72 psf
Pa Total = 72 psf + 30 H psf
Pa = 30 H psf
0.6H
0.2H
0.2H
Pa Total = 72 psf + 25 H psf
Pa = 25 H psf 72 psf
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 16
Design of the shield struts should be based on a value of 0.65 times the indicated pressure, Pa, for the
approximate trench depth. The wales and sheeting can be designed for a value of 2/3 the design strut value.
Placement of the shield may be made after the excavation is completed or driven down as the material is
excavated from inside of the shield. If placed after the excavation, some overexcavation may be required to
allow for the shield width and advancement of the shield. The shield may be placed at either the top or the
bottom of the pipe zone. Due to the anticipated thinness of the shield walls, removal of the shield after
construction should have negligible effects on the load factor of pipes. Shields may be successively placed with
conventional trenching equipment.
Vehicles, equipment, materials, etc. should be set back away from the edge of temporary excavations a
minimum distance of 15 feet from the top edge of the excavation. Surface waters should be diverted away from
temporary excavations and prevented from draining over the top of the excavation and down the slope face.
During periods of heavy rain, the slope face should be protected with sandbags to prevent drainage over the
edge of the slope, and a visqueen liner placed on the slope face to prevent erosion of the slope face.
Periodic observations of the excavations should be made by the geotechnical consultant to verify that the soil
conditions have not varied from those anticipated and to monitor the overall condition of the temporary
excavations over time. If at any time during construction conditions are encountered which differ from those
anticipated, the geotechnical consultant should be contacted and allowed to analyze the field conditions prior to
commencing work within the excavation.
Cal/OSHA construction safety orders should be observed during all underground work.
3.20 Utility Trench Backfill
The onsite fill soils will not be suitable for use as pipe bedding for buried utilities. All pipes should be bedded in a
sand, gravel or crushed aggregate imported material complying with the requirements of the Standard
Specifications for Public Works Construction Section 306-1.2.1. Crushed rock products that do not contain
appreciable fines should not be utilized as pipe bedding and/or backfill. Bedding materials should be densified to at
least 90% relative compaction (ASTM D1557) by mechanical methods. The geotechnical consultant should review
and approve of proposed bedding materials prior to use.
STRUTS(typ.)
SHIELD(typ.)
UNDISTURBED SOIL
BEDDING
1'min.
H1
Hsh
Dt
P = 30 Hsh psfa
HEIGHT OF SHIELD, Hsh = DEPTH OF TRENCH, Dt , MINUS DEPTH OF SLOPE, H1
TYPICAL SHORING
DETAIL
1:1
(
H
:
V
)
1:1 (H:V)
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 17
The on-site soils are expected to be suitable as trench backfill provided they are screened of organic matter and
rocks over 12 inches in diameter. Trench backfill should be densified to at least 90% relative compaction (ASTM
D1557). On-site granular soils may be water densified initially. Supplemental mechanical compaction methods may
be required in finer ground soils to attain the required 90% relative compaction.
All utility trench backfill within street right of way, utility easements, under or adjacent to sidewalks, driveways, or
building pads should be observed and tested by the geotechnical consultant to verify proper compaction. Trenches
excavated adjacent to foundations should not extend within the footing influence zone defined as the area within a
line projected at a 1:1 drawn from the bottom edge of the footing. Trenches crossing perpendicular to foundations
should be excavated and backfilled prior to the construction of the foundations. The excavations should be
backfilled in the presence of the geotechnical engineer and tested to verify adequate compaction beneath the
proposed footing.
Cal/OSHA construction safety orders should be observed during all underground work.
3.21 Pavement Sections
An R-value test was performed on the anticipated subgrade soil at the site in order to provide information on their
soil properties for design of pavement structural sections. The R-value test was done in compliance with CTM-301.
In the course of running the test the sample was unable to be compacted at the pressure required by the test
method without extruding around the mold, therefore, in accordance with the test methods an R-value of 79 was
assumed to the soil, Structural sections were designed using the procedures outlined in Chapter 630 of the
California Highway Design Manual (Caltrans, 2022) and the Caltrans Mechanistic-Emperical Tool program that
utilizes an equivalent resilient modulus, traffic index and project climate to calculate asphalt pavement sections.
This procedure uses the principle that the pavement structural section must be of adequate thickness to distribute
the load from the design traffic index (TI) to the subgrade soils in such a manner that the stresses from the applied
loads do not exceed the resilient modulus (Mr) of the soil.
Preliminary structural pavement sections are presented in the table below. Street type and corresponding traffic
index and minimum asphalt thickness are per City of Fontana Standard Plan Details 400, 401 and 402. R-value
testing of representative soils collected during of field investigation yield result of 79. Recommended pavement
section were calculated using an R-value of 70 (maximum permissible value per City of Fontana Standard Plan Detail
402) and traffic index values listed below. Calculated pavement sections were increased, when necessary, to meet
minimum asphalt thickness required by the City of Fontana minimum asphalt thickness of 4 inches.
Preliminary Structural Pavement Sections
Street Type Traffic
Index
Minimum
Asphalt
Thickness
Recommended
Pavement Section
(Asphalt Only)*
Recommended
Pavement Section
(Asphalt and Base)
Local 5.5 4.0” 4.0” AC 4.0”AC/4”AB
Collector 6.5 4.5” 4.5” AC 4.5”AC/4”AB
*Asphalt only sections will need to be underlain by a minimum of 12 inches of onsite soils
compacted to a minimum of 95% relative compaction.
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 18
Portland cement concrete (PCC) pavements for areas which are not subject to traffic loads may be designed with a
minimum thickness of 4.0 inches of Portland cement concrete on compacted non-expansive engineered fill soils. If
traffic loads are anticipated, PCC pavements should be designed for a minimum thickness of 6.0 inches of Portland
cement concrete on 12.0 inches of crushed aggregate base. Control joints to limit cracking of the concrete pavement
should be spaced no more than 10 feet apart. According to ACI 330, reinforcement to control is not necessary when
pavement is jointed to form short panel lengths of 15 feet or less. Reinforcement in the concrete paving will not add
to the load carrying capacity of the concrete. Any reinforcement of concrete paving may be included in design as
desired, to limit cracking of the concrete with at least number 4 reinforcing steel placed mid-height of the concrete
at 18-inches on center typical.
Prior to paving, the subgrade soils should be scarified and the moisture adjusted to within 2% of the optimum
moisture content. The subgrade soils should be compacted to a minimum of 90% relative compaction. All
aggregate base courses should be compacted to a minimum of 95% relative compaction.
3.22 Soil Infiltration Testing
Two soil infiltration tests were performed using the bore hole percolation test procedure described in the San
Bernardino County Stormwater Program Technical Guidance Document for Water Quality Management Plans
(WQMP).
The testing was performed in 8-inch diameter borings that were drilled with a truck mounted CME-75 drill rig. The
test holes extended to depths of 10 feet below the existing ground surface. The tests were performed in alluvial soil
consisting of sand with silt which is classified as SP by the Unified Soil Classification System.
Prior to performing the tests, the auger used to drill the test holes was rotated until cuttings were removed from the
hole. A 3-inch diameter perforated PVC pipe was then inserted into each test boring through the auger. A filter sock
was installed around the pipe prior to placement in the boring in lieu of gravel or sand packing to prevent siltation in
the pipe during testing and to facilitate removal of the pipe at the conclusion of the testing. Water levels were
measured to the nearest 0.01 of a foot using an electronic well sounder. The test holes were presoaked for 60
minutes and water levels were measured every 10 minutes because the initial water seeped away in less than 30
minutes. A total of 6 measurements were made following completion of presoaking.
Results of the testing are summarized in the table below.
Soil Infiltration Rates
Test No. Depth (ft) Soil Type Infiltration Rate
(in/hr)
P-1 10 SP 22.77
P-2 10 SP 22.83
Design of the infiltration systems should include an appropriate factor of safety to account for degradation of soil
conditions by fine grained materials carried by runoff, potential growth of vegetation, accumulation of trash and
other appropriate considerations. The factor of safety should be determined in accordance with the methodology
presented in San Bernardino County Program – Technical Guidance Document for Water Quality Management Plans
(Appendix D, Section VII) using a medium concern for the assessment method, low concerns for texture class
(granular soils) and soil variability (relatively homogeneous soils), a low concern for groundwater (depth to
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 19
groundwater greater than 100 feet), and appropriate design related considerations. Per the Technical Guidance
Document, the factor a safety should not be less than 2. We recommend that the slowest field test rate (P-2, 15.58
in/hr) be used to determine the design rate.
The above rates apply to existing natural soils. Compaction of soils will reduce infiltration rates. Therefore soils at
the bottom of the proposed infiltration systems should not be rolled or otherwise compacted, and construction
traffic should not be allowed in the area where the infiltration systems will be constructed. A maintenance plan
should also be developed and implemented to restore infiltration properties of soils that may be impacted by
sedimentation or other adverse conditions.
The test data sheets for the soil infiltration tests are presented in Appendix A.
3.23 Plan Review
Once a formal grading and foundation plans are prepared for the subject property, this office should review the
plans from a geotechnical viewpoint, comment on changes from the plan used during preparation of this report and
revise the recommendations of this report where necessary.
3.24 Geotechnical Observation and Testing During Rough Grading
The geotechnical engineer should be contacted to provide observation and testing during the following stages of
grading:
• During the clearing and grubbing of the site.
• During the demolition of any existing structures, buried utilities or other existing improvements.
• During excavation and overexcavation of compressible soils.
• During all phases of grading including ground preparation and filling operations.
• When any unusual conditions are encountered during grading.
A final geotechnical report summarizing conditions encountered during grading should be submitted upon
completion of the rough grading operations.
3.25 Post-Grading Geotechnical Observation and Testing
After the completion of grading the geotechnical engineer should be contacted to provide additional observation
and testing during the following construction activities:
• During trenching and backfilling operations of buried improvements and utilities to verify proper backfill
and compaction of the utility trenches.
• After excavation and prior to placement of reinforcing steel or concrete within footing trenches to verify
that footings are properly founded in competent materials.
• During fine or precise grading involving the placement of any fills underlying driveways, sidewalks,
walkways, or other miscellaneous concrete flatwork to verify proper placement, mixing and compaction of
fills.
• When any unusual conditions are encountered during construction.
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page 20
4.00 CLOSURE
The findings, conclusions and recommendations in this report were prepared in accordance with generally accepted
engineering and geologic principles and practices. This report has been prepared for North Fontana Investment
Company, LLC to be used solely for design purposes. Anyone using this report for any other purpose must draw
their own conclusions regarding required construction procedures and subsurface conditions.
The geotechnical and geologic consultant should be retained during the earthwork and foundation phases of
construction to monitor compliance with the design concepts and recommendations and to provide additional
recommendations as needed. Should subsurface conditions be encountered during construction that are different
from those described in this report, this office should be notified immediately so that our recommendations may be
re-evaluated.
FIGURES AND TABLES
SITE LOCATION AND
EARTHQUAKE FAULT ZONE MAP
Scale: 1" ≈ 2,000'
Base Map: California Division of Mines and Geology Earthquake Fault Zone Map of the Devore Quadrangle, 1995
Curtis Avenue Development
Lewis Management Corp
RMA Job No.: 00-232887-01
Figure 1
CURTIS AVENUE
C
I
T
R
U
S
A
V
E
N
U
E
EART
H
Q
U
A
K
E
F
A
U
L
T
Z
O
N
E
CUCA
M
O
N
G
A
F
A
U
L
T
SITE
REGIONAL GEOLOGIC MAP
Scale: 1" ≈ 4,000'
Source: Morton, D.M. and Matti, J.C., 2001, Geologic Map of the Devore 7.5' Quadrangle, San Bernardino County,
California, USGS OFR 01-173
RMA Job No.: 00-232887-01
Figure 2
Partial Legend
Curtis Avenue Development
Lewis Management Corp
- Modern wash deposits
- Modern alluvial fan deposits
- Young alluvial fan deposits - Granulitic gneiss, mylonite and cataclasite
- Very old alluvial fan deposits
- Old alluvial fan deposits
CUC
A
M
O
N
G
A
F
A
U
L
T
SAN
J
A
C
I
N
T
O
(
L
Y
T
L
E
C
R
E
E
K
)
F
A
U
L
T
SITE
- Boring Location
LEGEND
B-N
RMA Job No.: 00-232887-01
Figure 2
Curtis Avenue Development
Lewis Management Corp
LB-1
LB-2
LB-3
LB-5
LB-4
LB-6
LB-7
LB-13
LB-8
LB-9LB-11LB-10
LB-12
LT-12
LT-7
LT-6
LT-1
LT-2
LT-8
LT-11
LT-10
LT-9
LT-4 LT-3
B-1
B-2, P-1
B-3
B-4, P-2
B-5
B-6
- Boring Location used
B-N, P-N for infiltration testing
- Leighton 2005 Exploratory
- Leighton 2005 Boring Location
LT-N
LB-N
Trench Location
EXPLORATION MAP
Scale: 1" ≈ 200'
REGIONAL DEPTH TO GROUNDWATER MAP
Scale: 1" ≈ 4,000'
Base Map: Fife, D.L., 1974, Map Showing Surface Waters and Marches in Laste 1800's and Generalized Depth to ground
Water (1960), Upper Santa Ana Valley, Southwestern San Bernardino County, California, California Department of Mines
and Geology, SR-113, Plate 4-B.
RMA Job No.: 00-232887-01
Figure 4
Curtis Avenue Development
Lewis Management Corp
CUCAM
O
N
G
A
F
A
U
L
T
SA
N
J
A
C
I
N
T
O
F
A
U
L
T
S
A
N
J
A
C
I
N
T
O
(
L
Y
T
L
E
C
R
E
E
K
)
F
A
U
L
T
Partial Legend
--200-- - Line of equal depth to ground water in feet
BARR
I
E
R
J
SITE
NAP NAP
NAP
NAP
RIAL
T
O
-
C
O
L
T
O
N
F
A
U
L
T
REGIONAL GROUNDWATER ELEVATION MAP
Scale: 1" ≈ 4,000'
RMA Job No.: 00-232887-01
Figure 5
Curtis Avenue Development
Lewis Management Corp
Partial Legend
Qrc - River channel deposits
Qoal - Older alluvium
QTc - Continential deposits
bc - Basement complex
- Buried groundwater barrier
--200-- - Groundwater elevation contour in feet
- Geologic cross section (see Figure 6)
SITE
C
C'
C'C
Source: Dutcher and Garrett, 1963, U.S. Geological Survey Water Supply Paper 1419 (Plate 4)
RIAL
T
O
-
C
O
L
T
O
N
F
A
U
L
T
REGIONAL GEOLOGIC CROSS SECTION
Horizontal Scale: 1" ≈ 0.7 miles
Vertical Scale shown (1" ≈ 200')
Source: Dutcher and Garrett, 1963, U.S. Geological Survey Water Supply Paper 1419
RMA Job No.: 00-232887-01
Figure 6
Curtis Avenue Development
Lewis Management Corp
Qyal - Younger alluvium
(Holocene)
SITE (Projected)
Older alluvium
(Pleistocene)
Historic
groundwater level
RMA Job No.: 00-232887-01
Figure 7
Curtis Avenue Development
Lewis Management Corp
SITE
Source: Brandt, J.T., 2022, Mapping structural control through analysis of land-surface deformation for the Rialto-Colton
groundwater subbasin, San Bernardino County, California, 1992-2010: U.S. Geological Survey Open-File Report 2022-1030, 11 p.
RIALTO-COLTON GROUNDWATER SUBBASIN MAP
Scale: As shown
Base Map: California Geological Survey Fault Activity Map, 2010
SITE
RMA Job No.: 00-232887-01
Figure 8
Curtis Avenue Development
Lewis Management Corp
REGIONAL FAULT MAP
Scale: 1" ≈ 5 Miles'
Partial Legend
Orange - Holocene fault displacement
Green - Late Quaternary fault displacement
Purple - Quaternary fault
Black - Pre-Quaternary fault
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Table 1
Maximum Slip
Distance Distance Moment Rate
Fault Zone & geometry (km)(mi.)Magnitude (mm/yr)
Chino-Central Ave. (rl-r-o)29 18 6.7 1.0
Clamshell-Sawpit (r)38 24 6.5 0.5
Cleghorn (ll-ss)17 11 6.5 3.0
Cucamonga (r)3 2 6.9 5.0
Elsinore - Glen Ivy (rl-ss)37 23 6.8 5.0
Upper Elysian Park (r)60 37 6.4 1.3
Eureka Peak (rl-ss)98 61 6.4 0.6
Gravel Hills-Harper (rl-ss)94 58 7.1 0.6
Helendale - S Lockhart (rl-ss)57 35 7.3 0.6
Hollywood (ll-r-o)72 45 6.4 1.0
Johnson Valley (rl-ss)83 52 6.7 0.6
Landers (rl-ss)90 56 7.3 0.6
Lenwood-Lockhart (rl-ss)78 48 7.5 0.6
Malibu Coast (ll-r-o)99 62 6.7 0.3
Newport-Inglewood (rl-ss)72 45 6.9 1.5
North Frontal - Western (r)26 16 7.2 1.0
North Frontal - Eastern (r)64 40 6.7 0.5
Northridge (r)87 54 7 1.5
Palos Verde (rl-ss)86 53 7.3 3.0
Pinto Mountain (ll-ss)69 43 7.2 2.5
Puente Hills Blind Thrust (r)47 29 7.1 0.7
Raymond (ll-r-o)49 30 6.5 1.5
San Andreas (rl-ss)12 7 7.5 24.0
San Gabriel (rl-ss)78 48 7.2 1.0
San Jacinto - San Bernardino (rl-s 6 4 6.7 12.0
San Joaquin Hills (r)61 38 6.6 0.5
San Jose (ll-r-o)22 14 6.4 0.5
Santa Monica (ll-r-o)77 48 6.6 1.0
Santa Susana (r)98 61 6.7 5.0
Sierra Madre (r)26 16 7.2 2.0
Verdugo (r)64 40 6.9 0.5
Notes:
Fault geometry - (ss) strike slip, (r) reverse, (n) normal, (rl) right lateral, (ll) left lateral, (o) oblique
Fault and Seismic Data - California Geological Survey (Cao), 2003
NOTABLE FAULTS WITHIN 100 KILOMETERS AND SEISMIC DATA
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Table 1
Epicentral
Distance
Date Event Causitive Fault Magnitude (miles)
Dec. 12, 1812 Wrightwood San Andreas?7.3 28
Jan. 9, 1857 Fort Tejon San Andreas 7.9 244
Dec. 16, 1858 San Bernardino Area uncertain 6.0 14
Feb. 9,1890 San Jacinto uncertain 6.3 85
May 28, 1892 San Jacinto uncertain 6.3 86
July 30, 1894 Lytle Creek uncertain 6.0 14
July 22, 1899 Cajon Pass uncertain 6.4 11
Dec.25, 1899 San Jacinto San Jacinto 6.7 36
Sept. 20, 1907 San Bernardino Area uncertain 5.3 21
May 15, 1910 Elsinore Elsinore 6.0 31
April 21, 1918 Hemet San Jacinto 6.8 38
July 23, 1923 San Bernardino San Jacinto 6.0 14
March 11, 1933 Long Beach Newport-Inglewood 6.4 45
April 10, 1947 Manix Manix 6.4 79
Dec. 4, 1948 Desert Hot Springs San Andreas or Banning 6.5 65
July 21, 1952 Wheeler Ridge White Wolf 7.3 110
Feb. 9, 1971 San Fernando San Fernando 6.6 59
July 8, 1986 North Palm Springs Banning or Garnet Hills 5.6 51
Oct. 1, 1987 Whittier Narrows Puente Hills Thrust 6.0 37
Feb. 28, 1990 Upland San Jose 5.5 14
June 28, 1991 Sierra Madre Clamshell Sawpit 5.8 33
April 22, 1992 Joshua Tree Eureka Peak 6.1 68
June 28, 1992 Landers Johnson Valley & others 7.3 60
June 28, 1992 Big Bear uncertain 6.5 37
Jan. 17, 1994 Northridge Northridge Thrust 6.7 64
Oct. 16, 1999 Hector Mine Lavic Lake 7.1 77
July 5, 2019 Ridgecrest Little Lake Fault Zone 7.1 113
Notes:
Earthquake data: U.S.G.S. P.P. 1515 & online data, Southern California Earthquake Center &
California Geological Survey online data
Magnitudes prior to 1932 are estimated from intensity.
Magnitudes after 1932 are moment, local or surface wave magnitudes.
Site Location:
Site Longitude: -117.45647
Site Latitude: 34.14408
HISTORIC STRONG EARTHQUAKES IN SOUTHERN CALIFORNIA SINCE 1812
APPENDIX A
FIELD INVESTIGATION
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page A - 1
APPENDIX A
FIELD INVESTIGATION
A-1.00 FIELD EXPLORATION
A-1.01 Number of Borings
Our subsurface investigation consisted of 6 borings with 2 of the borings converted to infiltration tests drilled with a
CME-75 truck mounted hollow stem drill rig. In addition, we have reviewed the borings and exploratory trenches
completed by Leighton and Associates in 2005 and have included copies of their 13 borings and 12 exploratory
trenches as additional reference and exploration information for the site.
A-1.02 Location of Borings
A Boring Location Map showing the approximate locations of the borings is presented as Figure 1.
A-1.03 Boring Logging
Logs of borings were prepared by one of our staff and are attached in this appendix. The logs contain factual
information and interpretation of subsurface conditions between samples. The strata indicated on these logs
represent the approximate boundary between earth units and the transition may be gradual. The logs show
subsurface conditions at the dates and locations indicated, and may not be representative of subsurface conditions
at other locations and times.
Identification of the soils encountered during the subsurface exploration was made using the field identification
procedure of the Unified Soils Classification System (ASTM D2488). A legend indicating the symbols and definitions
used in this classification system and a legend defining the terms used in describing the relative compaction,
consistency or firmness of the soil are attached in this appendix. Bag samples of the major earth units were
obtained for laboratory inspection and testing, and the in-place density of the various strata encountered in the
exploration was determined
A-1.04 Infiltration Testing
2 soil infiltration tests were performed using the boring percolation test procedure described in the San Bernardino
County Stormwater Program Technical Guidance Document for Water Quality Management Plans (WQMP).
Locations of the tests are shown on Figure 3.
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page A - 2
Well graded gravel, gravel-sand mixtures.
Poorly graded gravel or gravel-sand mixtures,
Silty gravels, gravel-sand-silt mixtures.
Clayey gravels, gravel-sand-clay mixtures.
Well graded sands, gravelly sands, little or
Poorly graded sands or gravelly sands, little
Inorganic silts and very fine sands, rock flour
silty or clayey fine sands or clayey silts
Inorganic clays of low to medium plasticity,
gravelly clays, sandy clays, silty clays, lean
Organic silts and organic silty clays of low
Inorganic silts, micaceous or diatamaceous
fine sandy or silty soils, elastic silts.
Inorganic clays of high plasticity, fat clays.
Organic clays of medium to high plasticity,
BOUNDARY CLASSIFICATIONS: Soils possessing characteristics of two groups are designated by combinations of group symbols.
Pt
OH
CH
MH
OL
CL
ML
SC
SM
SP
SW
GC
GM
GP
GW
MAJOR DIVISIONS GROUP
SYMBOLS TYPICAL NAMES
CLEAN
GRAVELS
GRAVELS
WITH FINES
GRAVELS
COARSE
GRAINED
SOILS
SANDS
CLEAN
SANDS
SANDS
WITH FINES
SILTS AND CLAYS
SILTS AND CLAYS
FINE
GRAINED
SOILS
HIGHLY ORGANIC SOILS
(More than 50% of
material is LARGER
than No. 200 sieve
size)
(More than 50% of
coarse fraction is
LARGER than the
No. 4 sieve size.
(More than 50% of
coarse fraction is
SMALLER than the
No. 4 sieve size)
(Appreciable
amount of fines)
(Little or no fines)
(Appreciable amt.
of fines)
(Little or no fines)
(More than 50% of
material is SMALLER
than No. 200 sieve
size)
(Liquid limit LESS than 50)
(Liquid limit GREATER than 50)
little or no fines.
little or no fines.
no fines.
or no fines.
Silty sands, sand-silt mixtures.
Clayey sands, sand-clay mixtures.
with slight plasticity
clays.
plasticity.
organic silts.
Peat and other highly organic soils.
P
A
R
T
I
C
L
E
S
I
Z
E
L
I
M
I
T
S
S
I
L
T
O
R
C
L
A
Y
S
A
N
D
GR
A
V
E
L
CO
B
B
L
E
S
BO
U
L
D
E
R
S
U.
S
.
S
T
A
N
D
A
R
D
S
I
E
V
E
S
I
Z
E
FI
N
E
M
E
D
I
U
M
CO
A
R
S
E
FI
N
E
CO
A
R
S
E
No
.
2
0
0
No
.
4
0
No
.
1
0
No
.
4
3/
4
i
n
.
3
i
n
.
12
i
n
.
UNIFIED SOIL CLASSIFICATION SYSTEM
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page A - 3
I. SOIL STRENGTH/DENSITY
BASED ON STANDARD PENETRATION TESTS
Compactness of sand Consistency of clay
Penetration Resistance N
(blows/Ft)
Compactness
Penetration Resistance N
(blows/ft)
Consistency
0-4
4-10
10-30
30-50
>50
Very Loose
Loose
Medium Dense
Dense
Very Dense
<2
2-4
4-8
8-15
15-30
>30
Very Soft
Soft
Medium Stiff
Stiff
Very Stiff
Hard
N = Number of blows of 140 lb. weight falling 30 in. to drive 2-in OD sampler 1 ft.
BASED ON RELATIVE COMPACTION
Compactness of sand Consistency of clay
% Compaction Compactness % Compaction Consistency
<75
75-83
83-90
>90
Loose
Medium Dense
Dense
Very Dense
<80
80-85
85-90
>90
Soft
Medium Stiff
Stiff
Very Stiff
II. SOIL MOISTURE
Description Criteria
Dry Absence of moisture, dusty, dry to the touch
Moist Damp but not visible water
Wet Visible free water, usually soil is below water table
SOIL DESCRIPTION LEGEND
Curtis Avenue Development RMA Job No.:002328870
Lewis Management Corp
Date Drilled:
Logged By:
Location:
Drilling Equipment:
Boring Hole Diameter:
Drive Weights:
Boring No.Exploratory Boring Log
Material DescriptionSamples
This log contains factual information and interpretation of the subsurface conditions between the samples.
The stratum indicated on this log represent the approximate boundary between earth units and the
transition may be gradual. The log show subsurface conditions at the date and location indicated, and may
not be representative of subsurface conditions at other locations and times.
R
T
Ring Sample
Tube Sample
Bulk Sample
Sample Types:
SPT SampleS
Sheet 1 of 1
11162023
SL
CME75
8"
140 lbs.
5
10
15
20
25
Drop:30"
Groundwater
End of Boring
See Geologic Map
42S
S
B1
Page A4
50 for
5"
Total depth 26.5'
No Groundwater
SP
0.7
0.4 Gravel amount and size increases
S
S
S
66
50 for
6"
50 for
6"
1.6
2.3
SM
Poorly graded sand with gravel, minor cobbles and silt, fine to coarse
sand, poorly sorted, gray to yellowish-brown, dry
SILTY SAND with some gravel, Medium to coarse sand, dark brown to
brown, moist,
Curtis Avenue Development RMA Job No.:002328870
Lewis Management Corp
Date Drilled:
Logged By:
Location:
Drilling Equipment:
Boring Hole Diameter:
Drive Weights:
Boring No.Exploratory Boring Log
Material DescriptionSamples
This log contains factual information and interpretation of the subsurface conditions between the samples.
The stratum indicated on this log represent the approximate boundary between earth units and the
transition may be gradual. The log show subsurface conditions at the date and location indicated, and may
not be representative of subsurface conditions at other locations and times.
R
T
Ring Sample
Tube Sample
Bulk Sample
Sample Types:
SPT SampleS
Sheet 1 of 1
11162023
SL
CME75
8"
140 lbs.
5
10
15
20
25
Drop:30"
Groundwater
End of Boring
See Geologic Map
60S
S
B2
Page A5
50for
3"Total depth 10.5'
No Groundwater
0.6
0.3
SP
SM
Poorly graded sand with gravel, minor cobbles and silt, fine to coarse
sand, poorly sorted, gray to yellowish-brown, dry
SILTY SAND with some gravel, Medium to coarse sand, dark brown to
brown, moist,
Curtis Avenue Development RMA Job No.:002328870
Lewis Management Corp
Date Drilled:
Logged By:
Location:
Drilling Equipment:
Boring Hole Diameter:
Drive Weights:
Boring No.Exploratory Boring Log
Material DescriptionSamples
This log contains factual information and interpretation of the subsurface conditions between the samples.
The stratum indicated on this log represent the approximate boundary between earth units and the
transition may be gradual. The log show subsurface conditions at the date and location indicated, and may
not be representative of subsurface conditions at other locations and times.
R
T
Ring Sample
Tube Sample
Bulk Sample
Sample Types:
SPT SampleS
Sheet 1 of 1
11162023
SL
CME75
8"
140 lbs.
5
10
15
20
25
Drop:30"
Groundwater
End of Boring
See Geologic Map
42R
R
B3
Page A6
50 for
5"
Total depth 14.5'
No Groundwater
NA
NA
Gravel amount and size increases
S 66 Bit Broke at 14"
SP
SM
Poorly graded sand with gravel, minor cobbles and silt, fine to coarse
sand, poorly sorted, gray to yellowish-brown, dry
SILTY SAND with some gravel, Medium to coarse sand, dark brown to
brown, moist,
Curtis Avenue Development RMA Job No.:002328870
Lewis Management Corp
Date Drilled:
Logged By:
Location:
Drilling Equipment:
Boring Hole Diameter:
Drive Weights:
Boring No.Exploratory Boring Log
Material DescriptionSamples
This log contains factual information and interpretation of the subsurface conditions between the samples.
The stratum indicated on this log represent the approximate boundary between earth units and the
transition may be gradual. The log show subsurface conditions at the date and location indicated, and may
not be representative of subsurface conditions at other locations and times.
R
T
Ring Sample
Tube Sample
Bulk Sample
Sample Types:
SPT SampleS
Sheet 1 of 1
11162023
SL
CME75
8"
140 lbs.
5
10
15
20
25
Drop:30"
Groundwater
End of Boring
See Geologic Map
56S
S
B4
Page A7
50 for
6"Total depth 10.5'
No Groundwater
0.9
0.7
103.8
115.2
SP
SM
Poorly graded sand with gravel, minor cobbles and silt, fine to coarse
sand, poorly sorted, gray to yellowish-brown, dry
SILTY SAND with some gravel, Medium to coarse sand, dark brown to
brown, moist,
Curtis Avenue Development RMA Job No.:002328870
Lewis Management Corp
Date Drilled:
Logged By:
Location:
Drilling Equipment:
Boring Hole Diameter:
Drive Weights:
Boring No.Exploratory Boring Log
Material DescriptionSamples
This log contains factual information and interpretation of the subsurface conditions between the samples.
The stratum indicated on this log represent the approximate boundary between earth units and the
transition may be gradual. The log show subsurface conditions at the date and location indicated, and may
not be representative of subsurface conditions at other locations and times.
R
T
Ring Sample
Tube Sample
Bulk Sample
Sample Types:
SPT SampleS
Sheet 1 of 1
11162023
SL
CME75
8"
140 lbs.
5
10
15
20
25
Drop:30"
Groundwater
End of Boring
See Geologic Map
45R
R
B5
Page A8
50 for
6"
Total depth 16'
No Groundwater
0.3
0.8
Gravel amount and size increases
S 50 for
4"
Bit struggled to get through, stopped at 16 feet
SP
1.1
SM
Poorly graded sand with gravel, minor cobbles and silt, fine to coarse
sand, poorly sorted, gray to yellowish-brown, dry
SILTY SAND with some gravel, Medium to coarse sand, dark brown to
brown, moist,
Curtis Avenue Development RMA Job No.:002328870
Lewis Management Corp
Date Drilled:
Logged By:
Location:
Drilling Equipment:
Boring Hole Diameter:
Drive Weights:
Boring No.Exploratory Boring Log
Material DescriptionSamples
This log contains factual information and interpretation of the subsurface conditions between the samples.
The stratum indicated on this log represent the approximate boundary between earth units and the
transition may be gradual. The log show subsurface conditions at the date and location indicated, and may
not be representative of subsurface conditions at other locations and times.
R
T
Ring Sample
Tube Sample
Bulk Sample
Sample Types:
SPT SampleS
Sheet 1 of 1
11162023
SL
CME75
8"
140 lbs.
5
10
15
20
25
Drop:30"
Groundwater
End of Boring
See Geologic Map
50 for
6"S
S
B6
Page A9
50 for
6"Total depth 10.5'
No Groundwater
0.5
0.9
103.8
115.2
SP
Bit broke at 10 ft.
Poorly graded sand with gravel, minor cobbles and silt, fine to coarse
sand, poorly sorted, gray to yellowish-brown, dry
SM SILTY SAND with some gravel, Medium to coarse sand, dark brown to
brown, moist,
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page A - 10
Percolation Test Results
Project:Project No.:Date:11/16/2023
B-2, P-1 Tested By:
120
Length Width
8
Trial No.Start Time Stop Time
Time Interval
(min.)
Initial
Depth to
Water (in.)
Final Depth
to Water
(in.)
Change in
Water Level
(in.)
Greater than
or equal to
6"? (y/n)
1 9:45 AM 10:15 AM 30 24.0 98.4 74.4 Y
2 10:20 AM 10:50 AM 30 24.0 100.5 76.5 Y
Trial No.Start Time Stop Time
Δt
Time Interval
(min.)
Do
Initial
Depth to
Water (In.)
Df
Final Depth
to Water
(In.)
ΔD
Change in
Water Level
(in.)
Percolation
Rate
(min./in.)
1 11:00 AM 11:10 AM 10 24.0 100.2 76.2 0.131
2 11:10 AM 11:20 AM 10 34.0 109.8 75.8 0.132
3 11:20 AM 11:30 AM 10 31.0 105.2 74.2 0.135
4 11:40 AM 11:50 AM 10 24.0 99.8 75.8 0.132
5 11:55 AM 12:05 AM 10 28.0 102.6 74.6 0.134
6 12:10 PM 12:20 PM 10 24.0 97.9 73.9 0.135
Infiltration Rate (in/hr) = (ΔH*60min/hr*r)/Δt (r+2Havg)
H avg = (Ho- Hf)/2
22.77
Percolation Test Data Sheet
Curtis Ave Development
Test Hole No.:SL
00-232887-0
*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. Obtain at least twelve measurements per hole over at least six hours (approximate 30 minute
intervals) with a precision of at least 0.25".
Infiltration Rate (in/hr):
GPUSCS Soil Classification:
Test Hole Dimensions (inches)
Diameter In.) if round=
Test Hole Depth (In.) , DT:
Sides (if rectangular)=
Sandy Soil Criteria*
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page A - 11
Project:Project No.:Date:11/16/2023
B-4, P-2 Tested By:
120
Length Width
8
Trial No.Start Time Stop Time
Time Interval
(min.)
Initial
Depth to
Water (in.)
Final Depth
to Water
(in.)
Change in
Water Level
(in.)
Greater than
or equal to
6"? (y/n)
1 12:05 PM 12:35 PM 30 24.0 103.2 79.2 Y
2 12:40 PM 1:10 PM 30 24.0 99.7 75.7 Y
Trial No.Start Time Stop Time
Δt
Time Interval
(min.)
Do
Initial
Depth to
Water (In.)
Df
Final Depth
to Water
(In.)
ΔD
Change in
Water Level
(in.)
Percolation
Rate
(min./in.)
1 12:05 PM 12:15 PM 10 24.0 105.1 81.1 0.123
2 12:15 PM 12:25 PM 10 48.0 128.2 80.2 0.125
3 12:25 PM 12:35 PM 10 24.0 109.2 85.2 0.117
4 12:40 PM 12:50 PM 10 24.0 101.9 77.9 0.128
5 12:50 PM 1:00 PM 10 24.0 102.8 78.8 0.127
6 1:05 PM 1:15 PM 10 24.0 102.4 78.4 0.128
COMMEN Infiltration Rate (in/hr) = (ΔH*60min/hr*r)/Δt (r+2Havg)
H avg = (Ho - Hf)/2
22.83
Percolation Test Data Sheet
Curtis Ave Development
Test Hole No.:SL
00-232887-0
*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. Obtain at least twelve measurements per hole over at least six hours (approximate 30 minute
intervals) with a precision of at least 0.25".
Infiltration Rate (in/hr):
GPUSCS Soil Classification:
Test Hole Dimensions (inches)
Diameter In.) if round=
Test Hole Depth (In.) , DT:
Sides (if rectangular)=
Sandy Soil Criteria*
LEIGHTON AND ASSOCIATES (2015)
BORING AND EXPLORATORY TRENCH LOGS
APPENDIX B
LABORATORY TESTS
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page B - 1
APPENDIX B
LABORATORY TESTS
B-1.00 LABORATORY TESTS
B-1.01 Maximum Density
Maximum density - optimum moisture relationships for the major soil types encountered during the field
exploration were performed in the laboratory using the standard procedures of ASTM D1557.
B-1.02 Expansion Tests
Expansion index tests were performed on representative samples of the major soil types encountered by the test
methods outlined in ASTM D4829.
B-1.03 Soluble Sulfates and Chlorides
A test was performed on representative sample encountered during the investigation using the Caltrans Test
Methods CTM 417 and CTM 422.
B-1.04 Soil Reactivity (pH) and Electrical Resistivity
Representative soil sample was tested for soil reactivity (pH) and electrical resistivity using California Test Method
643. The pH measurement determines the degree of acidity or alkalinity in the soils.
B-1.05 Particle Size Analysis
Particle size analysis was performed on representative samples of the major soils types in accordance to the
standard test methods of the ASTM D422. The hydrometer portion of the standard procedure was not performed
and the material retained on the #200 screen was washed.
B-1.06 Direct Shear
Direct shear tests were performed on representative samples of the major soil types encountered in the test holes
using the standard test method of ASTM D3080 (consolidated and drained). Tests were performed on remolded
samples were tested at 90 percent relative compaction.
Shear tests were performed on a direct shear machine of the strain-controlled type. To simulate possible adverse
field conditions, the samples were saturated prior to shearing. Several samples were sheared at varying normal
loads and the results plotted to establish the angle of the internal friction and cohesion of the tested samples.
B-1.07 Resistance Value (R-Value)
Resistance Value tests were performed on representative samples of the major soil types encountered by the test
methods outlined in California 301.
B-1.08 Moisture Determination
Moisture content of the soil samples was performed in accordance to standard method for determination of water
content of soil by drying oven, ASTM D2216. The mass of material remaining after oven drying is used as the mass
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page B - 2
of the solid particles.
B-1.09 Density of Split-Barrel Samples
Soil samples were obtained by using a split-barrel sampler in accordance to standard method of ASTM D1586.
B-1.10 Test Results
Test results for all laboratory tests performed on the subject project are presented in this appendix.
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page B - 3
SAMPLE INFORMATION
Sample
Number
Sample
Description
Sample Location
Boring No. Depth (ft)
1 Yellowish brown to brownish gray poorly-graded sand with silt and gravel B-1 2-5
2 Yellowish brown to brownish gray poorly-graded sand with silt and gravel B-2 2-5
3 Yellowish brown to brownish gray poorly-graded sand with silt and gravel B-3 2-5
4 Yellowish brown to brownish gray poorly-graded sand with silt and gravel B-4 2-5
MAXIMUM DENSITY - OPTIMUM MOISTURE
Test Method: ASTM D1557
Sample
Number
Optimum Moisture
(Percent)
Maximum Density
(lbs/ft3)
1 7.5 136.7
2 6.2 142.1
EXPANSION TEST
Test Method: ASTM D4829
Sample
Number
Molding
Moisture
Content
(Percent)
Final
Moisture
Content
(Percent)
Initial
Dry
Density
(lbs/ft3)
Expansion
Index
Expansion
Classification
2 5.4 14.4 121.0 0 Very Low
SOLUBLE SULFATES
Test Method: CTM 417 and CTM 422
Sample
Number
Soluble Sulfate
(% by weight)
Soluble Chlorides
(ppm)
4 0.0111 24
SOIL REACTIVITY (pH) AND ELECTRICAL RESISTIVITY
Test Method: CTM 643
Sample
Number
pH
Resistivity
(Ohm-cm)
4 7.5 8,000
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page B - 4
SAND EQUIVALENT
Test Method: ASTM D2419
Sample
Number
Sand
Equivalent
4 46
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page B - 5
PARTICLE SIZE ANALYSIS
ASTM D422
Sample ID: 1
Location: B-1 @ 2-5 feet
Fraction A: Dry Net Weight (gms): 6,561
Fraction B: Dry Net Weight (gms):523.8
Net Retained Net Passing
Screen Size Weight (gms)Weight (gms)% Passing
Fraction A: 3"0 6561 100
1-1/2" 848 5713 87
3/4" 2225 4336 66
3/8" 2917 3644 56
#4 3236 3325 51
Net Retained Net Passing
Screen Size Weight (gms)Weight (gms)% Passing
Fraction B: #8 59.4 464.4 45
#16 130.4 393.4 38
#30 225.7 298.1 29
#50 324.7 199.1 19
#100 403.1 120.7 12
#200 455.4 68.4 7
0
10
20
30
40
50
60
70
80
90
100
0.010.1110100
%
P
a
s
s
i
n
g
Grain Size (mm)
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page B - 6
DIRECT SHEAR TEST
ASTM D3080
Sample ID:1
Maximum Dry Density (pcf) = 136.7
Optimum Moisture Content (%) = 7.5
Initial Dry Density (pcf) = 123.0
Initial Moisture Content (%) = 4.5
Final Moisture Content (%) = 13.4
Normal Peak Residual
Pressure Shear Resist Shear Resist
1000 984 804
2000 1488 1320
4000 3084 2712
Peak Residual
Cohesion (psf) =190 110
Friction Angle (deg) =36 33
Peak
Residual
0
500
1000
1500
2000
2500
3000
3500
0 500 1000 1500 2000 2500 3000 3500 4000 4500
Sh
e
a
r
S
t
r
e
s
s
(
p
s
f
)
Normal Stress (psf)
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page B - 7
Moisture Content (%)7.1 9.5 8.8
Dry Density (pcf)126.0 123.3 123.3
Exudation Pressure (psi)796 174 380
Stabilometer R Value 83 77 80
Expansion Pressure Dial 0 0 0
Use: Traffic Index = 5.0 Gravel Factor = 1.00
Thickness by Expansion (ft)
Thickness by Stabilometer (ft)0.27 0.37 0.32
Equilibrium Thick (ft)-
Equilibrium Pressure R Value n/a
Exudation Pressure R Value @ 300 psi 79
Expansion Pressure R-Value is based on the following structural section:
Thickness of AC (ft)=0.25 Gf(ac) = 2.50 W(ac) = 145
Thickness of Aggregate Base (ft)=0.33 Gf(base) = 1.10 W(base) =130
Gf(avg) = 1.70 W(avg) = 136
Use Exudation R Value
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
1.80
2.00
0.00 0.50 1.00 1.50 2.00
C
o
v
e
r
T
h
i
c
k
n
e
s
s
b
y
S
t
a
b
i
l
o
m
e
t
e
r
(
f
t
)
Cover Thickness by Expansion Pressure (ft)
Expansion Pressures
0
10
20
30
40
50
60
70
80
90
100
0 100 200 300 400 500 600 700 800
S
t
a
b
i
l
o
m
e
t
e
r
R
V
a
l
u
e
Exudation Pressure (psi)
Exudation Pressures
APPENDIX C
GENERAL EARTHWORK AND
GRADING SPECIFICATIONS
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page C - 1
APPENDIX C
GENERAL EARTHWORK AND GRADING SPECIFICATIONS
C-1.00 GENERAL DESCRIPTION
C-1.01 Introduction
These specifications present our general recommendations for earthwork and grading as shown on the approved
grading plans for the subject project. These specifications shall cover all clearing and grubbing, removal of existing
structures, preparation of land to be filled, filling of the land, spreading, compaction and control of the fill, and all
subsidiary work necessary to complete the grading of the filled areas to conform with the lines, grades and slopes as
shown on the approved plans.
The recommendations contained in the geotechnical report of which these general specifications are a part of shall
supersede the provisions contained hereinafter in case of conflict.
C-1.02 Laboratory Standard and Field Test Methods
The laboratory standard used to establish the maximum density and optimum moisture shall be ASTM D1557.
The insitu density of earth materials (field compaction tests) shall be determined by the sand cone method (ASTM
D1556), direct transmission nuclear method (ASTM D6938) or other test methods as considered appropriate by the
geotechnical consultant.
Relative compaction is defined, for purposes of these specifications, as the ratio of the in-place density to the
maximum density as determined in the previously mentioned laboratory standard.
C-2.00 CLEARING
C-2.01 Surface Clearing
All structures marked for removal, timber, logs, trees, brush and other rubbish shall be removed and disposed of off
the site. Any trees to be removed shall be pulled in such a manner so as to remove as much of the root system as
possible.
C-2.02 Subsurface Removals
A thorough search should be made for possible underground storage tanks and/or septic tanks and cesspools. If
found, tanks should be removed and cesspools pumped dry.
Any concrete irrigation lines shall be crushed in place and all metal underground lines shall be removed from the
site.
C-2.03 Backfill of Cavities
All cavities created or exposed during clearing and grubbing operations or by previous use of the site shall be cleared
of deleterious material and backfilled with native soils or other materials approved by the soil engineer. Said backfill
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page C - 2
shall be compacted to a minimum of 90% relative compaction.
C-3.00 ORIGINAL GROUND PREPARATION
C-3.01 Stripping of Vegetation
After the site has been properly cleared, all vegetation and topsoil containing the root systems of former vegetation
shall be stripped from areas to be graded. Materials removed in this stripping process may be used as fill in areas
designated by the soil engineer, provided the vegetation is mixed with a sufficient amount of soil to assure that no
appreciable settlement or other detriment will occur due to decaying of the organic matter. Soil materials
containing more than 3% organics shall not be used as structural fill.
C-3.02 Removals of Non-Engineered Fills
Any non-engineered fills encountered during grading shall be completely removed and the underlying ground shall
be prepared in accordance to the recommendations for original ground preparation contained in this section. After
cleansing of any organic matter the fill material may be used for engineered fill.
C-3.03 Overexcavation of Fill Areas
The existing ground in all areas determined to be satisfactory for the support of fills shall be scarified to a minimum
depth of 6 inches. Scarification shall continue until the soils are broken down and free from lumps or clods and until
the scarified zone is uniform. The moisture content of the scarified zone shall be adjusted to within 2% of optimum
moisture. The scarified zone shall then be uniformly compacted to 90% relative compaction.
Where fill material is to be placed on ground with slopes steeper than 5:1 (H:V) the sloping ground shall be benched.
The lowermost bench shall be a minimum of 15 feet wide, shall be a minimum of 2 feet deep, and shall expose firm
material as determined by the geotechnical consultant. Other benches shall be excavated to firm material as
determined by the geotechnical consultant and shall have a minimum width of 4 feet.
Existing ground that is determined to be unsatisfactory for the support of fills shall be overexcavated in accordance
to the recommendations contained in the geotechnical report of which these general specifications are a part.
C-4.00 FILL MATERIALS
C-4.01 General
Materials for the fill shall be free from vegetable matter and other deleterious substances, shall not contain rocks or
lumps of a greater dimension than is recommended by the geotechnical consultant, and shall be approved by the
geotechnical consultant. Soils of poor gradation, expansion, or strength properties shall be placed in areas
designated by the geotechnical consultant or shall be mixed with other soils providing satisfactory fill material.
C-4.02 Oversize Material
Oversize material, rock or other irreducible material with a maximum dimension greater than 12 inches, shall not be
placed in fills, unless the location, materials, and disposal methods are specifically approved by the geotechnical
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page C - 3
consultant. Oversize material shall be placed in such a manner that nesting of oversize material does not occur and
in such a manner that the oversize material is completely surrounded by fill material compacted to a minimum of
90% relative compaction. Oversize material shall not be placed within 10 feet of finished grade without the
approval of the geotechnical consultant.
C-4.03 Import
Material imported to the site shall conform to the requirements of Section 4.01 of these specifications. Potential
import material shall be approved by the geotechnical consultant prior to importation to the subject site.
C-5.00 PLACING AND SPREADING OF FILL
C-5.01 Fill Lifts
The selected fill material shall be placed in nearly horizontal layers which when compacted will not exceed
approximately 6 inches in thickness. Thicker lifts may be placed if testing indicates the compaction procedures are
such that the required compaction is being achieved and the geotechnical consultant approves their use.
Each layer shall be spread evenly and shall be thoroughly blade mixed during the spreading to insure uniformity of
material in each layer.
C-5.02 Fill Moisture
When the moisture content of the fill material is below that recommended by the soils engineer, water shall then be
added until he moisture content is as specified to assure thorough bonding during the compacting process.
When the moisture content of the fill material is above that recommended by the soils engineer, the fill material
shall be aerated by blading or other satisfactory methods until the moisture content is as specified.
C-5.03 Fill Compaction
After each layer has been placed, mixed, and spread evenly, it shall be thoroughly compacted to not less than 90%
relative compaction. Compaction shall be by sheepsfoot rollers, multiple-wheel pneumatic tired rollers, or other
types approved by the soil engineer.
Rolling shall be accomplished while the fill material is at the specified moisture content. Rolling of each layer shall
be continuous over its entire area and the roller shall make sufficient trips to insure that the desired density has
been obtained.
C-5.04 Fill Slopes
Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compacting of the
slopes may be done progressively in increments of 3 to 4 feet in fill height. At the completion of grading, the slope
face shall be compacted to a minimum of 90% relative compaction. This may require track rolling or rolling with a
grid roller attached to a tractor mounted side-boom.
Slopes may be over filled and cut back in such a manner that the exposed slope faces are compacted to a minimum
of 90% relative compaction.
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page C - 4
The fill operation shall be continued in six inch (6") compacted layers, or as specified above, until the fill has been
brought to the finished slopes and grades as shown on the accepted plans.
C-5.05 Compaction Testing
Field density tests shall be made by the geotechnical consultant of the compaction of each layer of fill. Density tests
shall be made at locations selected by the geotechnical consultant.
Frequency of field density tests shall be not less than one test for each 2.0 feet of fill height and at least every one
thousand cubic yards of fill. Where fill slopes exceed four feet in height their finished faces shall be tested at a
frequency of one test for each 1000 square feet of slope face.
Where sheepsfoot rollers are used, the soil may be disturbed to a depth of several inches. Density reading shall be
taken in the compacted material below the disturbed surface. When these readings indicate that the density of any
layer of fill or portion thereof is below the required density, the particular layer or portion shall be reworked until
the required density has been obtained.
C-6.00 SUBDRAINS
C-6.01 Subdrain Material
Subdrains shall be constructed of a minimum 4-inch diameter pipe encased in a suitable filter material. The subdrain
pipe shall be Schedule 40 Acrylonitrile Butadiene Styrene (ABS) or Schedule 40 Polyvinyl Chloride Plastic (PVC) pipe
or approved equivalent. Subdrain pipe shall be installed with perforations down. Filter material shall consist of 3/4"
to 1 1/2" clean gravel wrapped in an envelope of filter fabric consisting of Mirafi 140N or approved equivalent.
C-6.02 Subdrain Installation
Subdrain systems, if required, shall be installed in approved ground to conform the approximate alignment and
details shown on the plans or herein. The subdrain locations shall not be changed or modified without the approval
of the geotechnical consultant. The geotechnical consultant may recommend and direct changes in the subdrain
line, grade or material upon approval by the design civil engineer and the appropriate governmental agencies.
C-7.00 EXCAVATIONS
C-7.01 General
Excavations and cut slopes shall be examined by the geotechnical consultant. If determined necessary by the
geotechnical consultant, further excavation or overexcavation and refilling of over excavated areas shall be
performed, and/or remedial grading of cut slopes shall be performed.
C-7.02 Fill-Over-Cut Slopes
Where fill-over-cut slopes are to be graded the cut portion of the slope shall be made and approved by the
geotechnical consultant prior to placement of materials for construction of the fill portion of the slope.
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page C - 5
C-8.00 TRENCH BACKFILL
C-.01 General
Trench backfill within street right of ways shall be compacted to 90% relative compaction as determined by the
ASTM D1557 test method. Backfill may be jetted as a means of initial compaction; however, mechanical compaction
will be required to obtain the required percentage of relative compaction. If trenches are jetted, there must be a
suitable delay for drainage of excess water before mechanical compaction is applied.
C-9.00 SEASONAL LIMITS
C-9.01 General
No fill material shall be placed, spread or rolled while it is frozen or thawing or during unfavorable weather
conditions. When the work is interrupted by heavy rain, fill operations shall not be resumed until field tests by the
soils engineer indicate that the moisture content and density of the fill are as previously specified.
C-10.00 SUPERVISION
C-10.01 Prior to Grading
The site shall be observed by the geotechnical consultant upon completion of clearing and grubbing, prior to the
preparation of any original ground for preparation of fill.
The supervisor of the grading contractor and the field representative of the geotechnical consultant shall have a
meeting and discuss the geotechnical aspects of the earthwork prior to commencement of grading.
C-10.02 During Grading
Site preparation of all areas to receive fill shall be tested and approved by the geotechnical consultant prior to the
placement of any fill.
The geotechnical consultant or his representative shall observe the fill and compaction operations so that he can
provide an opinion regarding the conformance of the work to the recommendations contained in this report.
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page C - 6
RETAINING WALL DRAINAGE DETAIL
Soil backfill, compacted to
90% relative compaction*
Filter fabric envelope
(Mirafi 140N or approved
equivalent) **
Minimum of 1 cubic foot
3" diameter perforated
PVC pipe (schedule 40 or
equivalent) with perforations
oriented down as depicted
minimum 1% gradient to
suitable outlet.
3" min.
Wall footing
Compacted fill
Finished Grade
Retaining wall
Wall waterproofing
per architect's
specifications
* Based on ASTM D1557
** If class 2 permeable material (See
gradation to left) is used in place of
3/4" - 1 1/2" gravel. Filter fabric may
be deleted. Class 2 permeable material
compacted to 90% relative compaction. *
SPECIFICATIONS FOR CLASS 2
PERMEABLE MATERIAL
(CAL TRANS SPECIFICATIONS)
Sieve Size % Passing
1"
3/4"
3/8"
No.4
No.8
No.30
No.50
No.200 0-3
0-7
5-15
18-33
25-40
40-100
90-100
100
per linear foot of 3/4"
crushed rock
50 feet on center to a
joints or outlet drain at
Provide open cell head
suitable drainage device
.
..
.
.
.
.
..
.
.
.
.
APPENDIX D
REFERENCES
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page D - 1
APPENDIX D
REFERENCES
1. Brandt, J.T., 2022, Mapping structural control through analysis of land-surface deformation for the Rialto-
Colton groundwater subbasin, San Bernardino County, California, 1992–2010: U.S. Geological Survey Open-
File Report 2022–1030, 11 p.
2. California Building Standards Commission, 2022 California Building Code.
3. California Department of Conservation, Division of Mines and Geology, 2008, Guidelines for Evaluating and
Mitigating Seismic Hazards in California, Special Publication 117A.
4. California Department of Water Resources, 1970, Meeting Water Demands in the Chino-Riverside Area,
Bulletin No. 104-3.
5. California Division of Mines and Geology, 1995, Earthquake Fault Zone Map, Devore Quadrangle, Effective
Date June 1, 1995.
6. California Geological Survey, 2018, Earthquake Fault Zones, A Guide for Governmental Agencies, Property
Owners, and Geoscience Practitioners for Assessing Fault Rupture Hazards in California, Special Publication 42.
7. California Geological Survey, 2008, Guidelines for Evaluating and Mitigating Seismic Hazards in California,
Special Publication 117A.
8. Cao, Y. and others, 2003, The Revised 2002 California Probabilistic Seismic Hazard Maps, June 2003.
9. Federal Emergency Management Agency, 2008, Flood Insurance Rate Map (FIRM) Map No. 0607C7915H,
dated August 28, 2008.
10. Fife, D.L. and others, 1976, Geologic Hazards in Southwestern San Bernardino County, California: California
Division of Mines and Geology Special Report 113.
11. Fontana, City of, 2018, General Plan.
12. Google Earth, Aerial Photographs, 2011-2023, 2009, 2007, 2004, 2003 and 1994.
13. Historicaerials.com, Aerial Photographs, 2012, 2005, 2002, 1994, 1980, 1966, 1959 and 1938.
14. Ishihara, K., 1985, Stability of Natural Deposits during Earthquakes, Proceedings of the Eleventh International
Conference on Soil Mechanics and Foundation Engineering, San Francisco, CA.
15. Leighton Consulting, Inc, 2005, Preliminary Geotechnical Investigation, Fontana Unified School District
Proposed Elementary School Number 33, 15900± Curtis Avenue, Fontana California, Project Number 600846-
002, Dated November 9, 2005.
16. Jennings, C.W., Burnett, J.L. and Troxel, B.W., 1962, Geologic Map of California: California Division of Mine and
Curtis Avenue Development January 9, 2024
North Fontana Investment Company, LLC RMA Job No.: 00-232887-01
Page D - 2
Geology Geologic Atlas of California.
17. Jennings, C.W., and Bryant, W.A, 2010, Fault Activity Map of California, California Geological Survey, Geologic
Data Map No. 6.
18. Martin, G.R. and Lew, M., 1999, Recommended Procedures for Implementation of DMG Special Publication
117, Guidelines for Analyzing and Mitigating Liquefaction Hazards in California, Southern California Earthquake
Center publication.
19. Morton, D.M. and Matti, J.C., 1991, Geologic Map of the Devore 7.5-minute Quadrangle, San Bernardino
County, California: U.S. Geological Survey OF 90-695.
20. SEAOC Seismology Committee, 2019, “Seismically Induced Lateral Earth Pressures on Retaining Structures and
Basement Walls,” August 2019, The SEAOC Blue Book: Seismic Design Recommendations, Structural Engineers
Association of California, Sacramento, CA.
21. Seed, H.B. and Whitman, R.V., 1970, Design of Earth Structures for Dynamic Loads in American Society of Civil
Engineers Specialty Conference State-of-the Art Paper, Lateral Stresses in the Ground and Design of Earth-
Retaining Structures.
22. San Bernardino County General Plan, 2010, Hazard Overlay Map FH21B.
23. Southern California Earthquake Center online fault and seismic data, https://www.scec.org/.
24. Tokimatsu, K. and Seed, H.B., 1987, Evaluation of Settlements in Sands Due to Earthquake Shaking, Journal of
Soil Mechanics and Foundation Engineering, Vol. 113, No. 8.
25. U.S. Army Corps of Engineers, 2003, Engineering and Design - Stability Analysis of Concrete Structures,
Publication CECW-E, Circular No. 1110-2-6058, Appendix G, http://www.usace.army.mil/publications/eng-
circulars/ec1110-2-6058/.
26. Woolfenden, L.R. and Kadhim, D, 1997, Geohydrology and Water Chemistry in the Rialto-Colton Basin, San
Bernardino County, California, United States Geological Survey Water-Resources Investigations Report 97-
4012.