HomeMy WebLinkAboutCT 2018-0001; WALNUT BEACH HOMES; REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION; 2017-11-14' ..
REPORT OF PRELIMINARY
GEOTECHNICAL INVESTIGATION
Proposed Walnut Avenue Residential Project
362 Walnut Avenue
Carlsbad, California
JOB NO. 17-11664
14 November 2017
Prepared for:
Rincon Real Estate Group, Inc.
• \ .. ~-Geotechnical Exploration, Inc.
SOIL AND FOUNDATION ENGINEERING • GROUNDWATER • ENGINEERING GEOLOGY
14 November 2017
Rincon Real Estate Group, Inc.
3005 S. El Camino Real
San Clemente, CA 92672
Attn: Mr. Kevin Dunn
lob No. 17-11664
Subject: Report of Preliminary Geotechnical Investigation
Proposed Walnut Avenue Residential Project
362 Walnut Avenue
Carlsbad, California
Dear Mr. Dunn:
In accordance with your request, and our proposal of October 11, 2017,
Geotechnica/ Exploration, Inc. has performed a preliminary geotechnical
investigatio'n and infiltration testing for the subject property. The field work was
performed on October 16, 2017.
In our opinion, if the conclusions and recommendations presented in this report are
implemented during site preparation and construction, the site will be suited for the
proposed residential project and associated improvements.
This opportunity to be of service is sincerely appreciated. Should you have any
questions concerning the following report, please do not hesitate to contact us.
Reference to our Job No. 17-11664 will expedite a response to your inquiries.
Respectfully submitted,
GEOTECHNICAL EXPLORATION, INC.
JetrT1e A. Cerros, P.E.
R.C.E. 34422/G.E. 2007
Senior Geotechnical Engineer
7420TRADE STREETO SAN DIEGO, CA. 921210 (858) 549-7222• FAX: (858) 549-1604 ill EMAIL: geotech@gel-sd.com
. ' ) .
I.
II.
III.
IV.
V.
VI.
VII.
VIII.
IX.
X.
XI.
XII.
PROJECT SUMMARY
SCOPE OF WORK
SITE DESCRIPTION
FIELD INVESTIGATION
TABLE OF CONTENTS
LABORATORY TESTS & SOIL INFORMATION
REGIONAL GEOLOGIC DESCRIPTION
SITE-SPECIFIC SOIL & GEOLOGIC DESCRIPTION
GEOLOGIC HAZARDS
GROUNDWATER
CONCLUSIONS AND RECOMMENDATIONS
GRADING NOTES
LlMITATIONS
REFERENCES
FIGURES
I.
II.
Illa-e.
IV.
V.
Vicinity Map
Plot Plan
Exploratory Excavation Logs
Laboratory Test Results
Geologic Map and Legend
APPENDICES
A. Unified Soil Classification System
B. Infiltration Test Data and Infiltration Rate Calculations
C. USDA Web Soil Survey Map
D. USGS Design Maps Summary Report
1
1
2
2
5
7
11
12
20
22
38
39
'
REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION
Proposed Walnut Avenue Residential Project
362 Walnut Avenue
Carlsbad, California
JOB NO. 17-11664
The following report presents the findings and recommendations of Geotechnical
Exploration, Inc. for the subject project.
I. PROJECT SUMMARY
It is our understanding, based on communications with you, that the existing
single-story, single-family residential structures will be removed, and the site will
be developed to receive 6 two-unit residential structures with attached garages and
associated improvements. The proposed residential structures are to be
constructed of standard-type building materials utilizing a conventional foundation
system.
Final construction plans have not been provided to us during the preparation of this
report, however, when completed they should be made available for our review.
Additional or modified recommendations will be provided at that time if warranted.
II. SCOPE OF WORK
The scope of work performed for this investigation included a site reconnaissance
and subsurface exploration program, laboratory testing, geotechnical engineering
analysis of the field and laboratory data, infiltration testing, and the preparation of
this report. The data obtained and the analyses performed were for the purpose of
providing design and construction criteria for the project earthwork, building
foundations, and slab on-grade floors.
•
• Proposed Walnut Avenue Residence Project
Carlsbad, California
III. SITE DESCRIPTION
Job No. 17-11664
Page 2
The property is known as Assessor's Parcel No. 204-132-17-00, Parcel 2, per
Recorded Map PM 00425, in the City of Carlsbad, County of San Diego, State of
California. Refer to Figure No. I, the Vicinity Map, for the site location.
The site, more particularly referred to as 362 Walnut Avenue, consists of
approximately 0.57-acre. The lot is located on the north side of Walnut Avenue, in
the City of Carlsbad. The property is bordered on the north, at approximately the
same elevation, by a multi-family residential property; on the east, at slightly lower
elevation, by a multi-family residential property; on the west, at slightly lower
elevation by a multi-family residential property; and to the south at slightly lower
elevation by Walnut Avenue. In general, the lot slopes very gently to the
southwest and northeast. For Plot Plan, refer to Figure No. II.
The existing structures on the property consist of two single-story single-family
residences and associated improvements. Vegetation consists of ornamental
landscaping including mature trees, lawn and decorative shrubbery.
The building pad is relatively level at an approximate elevation of 55 feet above
mean sea level (MSL). Elevations across the property range from approximately 52
feet above (MSL) in the southwest corner of the property to approximately 56 feet
above (MSL) in the northwest corner of the property.
IV. FIELD INVESTIGATION
The field investigation consisted of a surface reconnaissance and a subsurface
exploration program utilizing hand tools to investigate and sample the subsurface
•
• Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 3
soils. Five exploratory excavations were advanced across the lot in the vicinity of
the proposed structures. The exploratory excavations were advanced to a
maximum depth of 3 feet, in order to obtain representative soil samples and to
define the soil profile across the project area.
The soils encountered in the exploratory excavations were continuously logged in
the field by our geologist and described in accordance with the Unified Soil
Classification System (refer to Appendix A). The approximate locations of the
exploratory excavations are shown on the Plot Plan, Figure No. II.
Representative samples were obtained from the exploratory excavations at selected
depths appropriate to the investigation. All samples were returned to our
laboratory for evaluation and testing. Exploratory excavation logs were prepared
on the basis of our observations and laboratory test results. Logs of the
exploratory excavations are attached as Figure Nos. IIIa-e.
A. Infiltration Testing
We performed simple open pit falling head testing at two locations in the northeast
corner of the property at a depth of 36 inches at INF-1, and 36.5 inches at INF-2
per the requirements of the City of Carlsbad Storm Water Standards, BMP Design
Manual, in accordance with Appendix D. Testing at the two locations (INF-1 and
INF-2), revealed falling head rates of 10.000 and 9.231 minutes/inch, respectively.
The simple open pit falling head test rate results for INF-1 and INF-2 have been
converted to infiltration rates, using the Porchet Method and indicate infiltration
rates of 4.000-and 4.216-inch/hour, respectively. Refer to Appendix B for simple
open pit test rate results and simple open pit to infiltration rate calculations.
•
• Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 4
Formational materials referred to as Quaternary-age Old Paralic deposits (Qop5_,)
were encountered underlying the thin veneer of topsoil and filf soils in both
exploratory infiltration excavations. Laboratory test results at infiltration test
location INF-1 and INF-2, indicate 16% and 19% of the soils passed the #200
sieve, respectively.
Based on our review of USDA Web Soil Survey map, the site has been assigned to
hydrologic soil group (HSG) B. Refer to Appendix C for USDA Web Soil Survey Map.
As part of our geologic/geotechnical site evaluation, we considered the following
issues:
1. The site is not subject to high groundwater conditions (within 10 feet of the
base of the infiltration facility.
2. The site is not in relatively close proximity to a known contaminated soil
site.
3. Portions of the site are underlain by artificial fill soils over medium dense
silty sand formational soils, but not subject to hydroconsolidation.
4. The proposed bio-retention basin has infiltration rates between of 4.000-and
4.216-inch/hour without an applied factor of safety.
5. Portions of the site may have a silt plus clay percentage of greater than 50.
6. The proposed bio-retention basin is not underlain at relatively shallow
depths by practically impermeable formational soils.
•
• Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 5
7. The proposed bio-retention basin is not located within 100 feet from a
known drinking water well.
8. The proposed bio-retention basin is not located within 100 feet from an on-
site septic system or designated expansion area.
9. The proposed bio-retention basin is not located adjacent to a slope steeper
than 25 percent.
Based on the results of our simple open pit falling head testing and evaluation of
the infiltration rates, it is our professional opinion that the proposed bio-retention
basin has favorable soil conditions and appreciable infiltration rates for the design
of full infiltration BMPs. However, we recommend the sidewalls of the proposed
basin be lined and the basin be located at least 5 feet away from any proposed
structures, retaining walls and utility trenches.
V. LABORATORY TESTS&. SOIL INFORMATION
Laboratory tests were performed on the retrieved soil samples in order to evaluate
their index, strength, expansion, and compressibility properties. The test results
are presented on Figures Nos. IIIa-e and IV. The following tests were conducted on
representative soil samples:
1. Moisture Content (ASTM D2216-10)
2. Determination of Percentage of Particles Smaller than #200 Sieve
(ASTM D1140-14)
3. Laboratory Compaction Characteristics (ASTM Dl 557-12)
4. Density Measurements (ASTM D2937)
•
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 6
Moisture content measurements were performed to establish the in situ moisture of
samples retrieved from the exploratory excavations. Moisture content and density
measurements were performed by ASTM methods D2216 and D2937. These
density tests help to establish the in situ moisture and density of samples retrieved
from the exploratory excavations.
The particle size smaller than a No. 200 sieve analysis (ASTM D1140-06) tests
(ASTM D4318-05) aid in classifying the tested soils in accordance with the Unified
Soil Classification System and provide qualitative information related to engineering
characteristics such as expansion potential, permeability, and shear strength.
Laboratory compaction tests (ASTM D1557-12) establish the laboratory maximum
dry density and optimum moisture content of the tested soils and are also used to
aid in evaluating the strength characteristics of the soils.
The expansion potential of soils is determined, when necessary, utilizing the
Standard Test Method for Expansion Index of Soils (ASTM D4829). In accordance
with the same Standard (Table 5.3), potentially expansive soils are classified as
follows:
EXPANSION INDEX POTENTIAL EXPANSION
Oto 20 Verv low
21 to 50 Low
51 to 90 Medium
91 to 130 Hiah
Above 130 Verv hiah
•
• Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 7
Based on the particle size test results and our experience with the encountered
soils, it is our opinion that the on-site fill and formational soils in general possess a
low expansion potential.
VI. REGIONAL GEOLOGIC DESCRIPTION
San Diego County has been divided into three major geomorphic provinces: the
Coastal Plain, the Peninsular Ranges and the Salton Trough. The Coastal Plain
exists west of the Peninsular Ranges. The Salton Trough is east of the Peninsular
Ranges. These divisions are the result of the basic geologic distinctions between
the areas. Mesozoic metavolcanic, metasedimentary and plutonic rocks
predominate in the Peninsular Ranges with primarily Cenozoic sedimentary rocks to
the west and east of this central mountain range (Demere, 1997).
In the Coastal Plain region, where the subject property is located, the "basement"
consists of Mesozoic crystalline rocks. Basement rocks are also exposed as high
relief areas (e.g., Black Mountain northeast of the subject property and Cowles
Mountain near the San Carlos area of San Diego). Younger Cretaceous and Tertiary
sediments lap up against these older features. These sediments form a "layer
cake" sequence of marine and non-marine sedimentary rock units, with some
formations up to 140 million years old. Faulting related to the La Nacion and Rose
Canyon Fault zones has broken up this sequence into a number of distinct fault
blocks in the southwestern part of the county. Northwestern portions of the county
are relatively undeformed by faulting (Demere, 1997).
The Peninsular Ranges form the granitic spine of San Diego County. These rocks
are primarily plutonic, forming at depth beneath the earth's crust 140 to 90 million
years ago as the result of the subduction of an oceanic crustal plate beneath the
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 8
North American continent. These rocks formed the much larger Southern California
batholith. Metamorphism associated with the intrusion of these great granitic
masses affected the much older sediments that existed near the surface over that
period of time. These metasedimentary rocks remain as roof pendants of marble,
schist, slate, quartzite and gneiss throughout the Peninsular Ranges. Locally,
Miocene-age volcanic rocks and flows have also accumulated within these
mountains (e.g., Jacumba Valley). Regional tectonic forces and erosion over time
have uplifted and unroofed these granitic rocks to expose them at the surface
(Demere, 1997).
The Salton Trough is the northerly extension of the Gulf of California. This zone is
undergoing active deformation related to faulting along the Elsinore and San Jacinto
Fault Zones, which are part of the major regional tectonic feature in the
southwestern portion of California, the San Andreas Fault Zone. Translational
movement along these fault zones has resulted in crustal rifting and subsidence.
The Salton Trough, also referred to as the Colorado Desert, has been filled with
sediments to depth of approximately 5 miles since the movement began in the
early Miocene, 24 million years ago. The source of these sediments has been the
local mountains as well as the ancestral and modern Colorado River (Demere,
1997).
As indicated previously, the San Diego area is part of a seismically active region of
California. It is on the eastern boundary of the Southern California Continental
Borderland, part of the Peninsular Ranges Geomorphic Province. This region is part
of a broad tectonic boundary between the North American and Pacific Plates. The
actual plate boundary is characterized by a complex system of active, major, right-
lateral strike-slip faults, trending northwest/southeast. This fault system extends
eastward to the San Andreas Fault (approximately 70 miles from San Diego) and
Proposed Walnut Avenue Residence Project
Carlsbad, California
westward to the San Clemente Fault (approximately 50
Diego) (Berger and Schug, 1991).
Job No. 17-11664
Page 9
miles off-shore from San
In California, major earthquakes can generally be correlated with movement on
active faults. As defined by the California Division of Mines and Geology (Hart,
E.W., 1980), an "active" fault is one that has had ground surface displacement
within Holocene time (about the last 11,000 years). Additionally, faults along which
major historical earthquakes have occurred (about the last 210 years in California)
are also considered to be active (Association of Engineering Geologist, 1973). The
California Division of Mines and Geology (now the California Geological Survey)
defines a "potentially active" fault as one that has had ground surface displacement
during Quaternary time, that is, between 11,000 and 1.6 million years (Hart, E.W.,
1980).
During recent history, prior to April 2010, the San Diego County area has been
relatively quiet seismically. No fault ruptures or major earthquakes had been
experienced in historic time within the greater San Diego area. Since earthquakes
have been recorded by instruments (since the 1930s), the San Diego area has
experienced scattered seismic events with Richter magnitudes generally less than
M4.0. During June 1985, a series of small earthquakes occurred beneath San
Diego Bay, three of which were recorded at M4.0 to M4.2. In addition, the
Oceanside earthquake of July 13, 1986, located approximately 26 miles offshore of
the City of Oceanside, had a magnitude of MS.3 (Hauksson and Jones, 1988).
On June 15, 2004, a M5.3 earthquake occurred approximately 45 miles southwest
of downtown San Diego (26 miles west of Rosarito, Mexico). Although this
earthquake was widely felt, no significant damage was reported. Another widely felt
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 10
earthquake on a distant southern California fault was a MS.4 event that took place
on July 29, 2008, west-southwest of the Chino Hills area of Riverside County.
Several earthquakes ranging from MS.0 to M6.0 occurred in northern Baja
California, centered in the Gulf of California on August 3, 2009. These were felt in
San Diego but no injuries or damage was reported. A MS.8 earthquake followed by
a M4.9 aftershock occurred on December 30, 2009, centered about 20 miles south
of the Mexican border city of Mexicali. These were also felt in San Diego, swaying
high-rise buildings, but again no significant damage or injuries were reported.
On Easter Sunday April 4, 2010, a large earthquake occurred in Baja California,
Mexico. It was widely felt throughout the southwest including Phoenix, Arizona and
San Diego in California. This M7.2 event, the Sierra El Mayor earthquake, occurred
in northern Baja California, approximately 40 miles south of the Mexico-USA border
at shallow depth along the principal plate boundary between the North American
and Pacific plates. According to the U. S. Geological Survey this is an area with a
high level of historical seismicity, and it has recently also been seismically active,
though this is the largest event to strike in this area since 1892. The April 4, 2010,
earthquake appears to have been larger than the M6.9 earthquake in 1940 or any
of the early 20th century events (e.g., 1915 and 1934) in this region of northern
Baja California. The event caused widespread damage to structures, closure of
businesses, government offices and schools, power outages, displacement of people
from their homes and injuries in the nearby major metropolitan areas of Mexicali in
Mexico and Calexico in Southern California.
This event's aftershock zone extends significantly to the northwest, overlapping
with the portion of the fault system that is thought to have ruptured in 1892.
Some structures in the San Diego area experienced minor damage and there were
• Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 11
some injuries. Ground motions for the April 4, 2010, main event, recorded at
stations in San Diego and reported by the California Strong Motion Instrumentation
Program (CSMIP), ranged up to 0.058g. Aftershocks from this event continue to
the date of this report along the trend northwest and south of the original event,
including within San Diego County, closer to the San Diego metropolitan area.
There have been hundreds of these earthquakes including events up to MS.7.
On July 7, 2010, a MS.4 earthquake occurred in Southern California at 4:53 pm
(Pacific Time) about 30 miles south of Palm Springs, 25 miles southwest of Indio,
and 13 miles north-northwest of Borrego Springs. The earthquake occurred near
the Coyote Creek segment of the San Jacinto Fault. The earthquake exhibited right
lateral slip to the northwest, consistent with the direction of movement on the San
Jacinto Fault. The earthquake was felt throughout Southern California, with strong
shaking near the epicenter. It was followed by more than 60 aftershocks of Ml.3
and greater during the first hour. Seismologists expect continued aftershock
activity.
In the last SO years, there have been four other earthquakes in the magnitude MS.0
range within 20 kilometers of the Coyote Creek segment: MS.8 in 1968, MS.3 on
2/25/1980, MS.0 on 10/31/2001, and MS.2 on 6/12/2005. The biggest earthquake
near this location was the M6.0 Buck Ridge earthquake on 3/25/1937,
VII. SITE-SPECIFIC SOIL & GEOLOGIC DESCRIPTION
Our field work, reconnaissance and review of the geologic map by Kennedy and
Tan, 2007, "Geologic Map of Oceanside, 30'x60' Quadrangle, CA," indicate that the
site is underlain by Quaternary-age Old Paralic Deposits (Qop6•7) formational
materials. The formational soils are overlain by approximately 0.25 to 1 feet of
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 12
topsoil and fill soils across the lot (Refer to the Excavation Logs, Figure Nos. IIIa-e).
Figure No. V presents a plan view geologic map (Kennedy and Tan, 2007) of the
general area of the site.
Fill and Topsoils (Oaf): The lot is overlain by approximately 0.25 to 0.5 feet of
topsoils as encountered in all of the exploratory excavations with the exception of
exploratory excavation HP-4. Fill soils were encountered in exploratory excavation
HP-4 to a depth of approximately 1 foot. The encountered fill and topsoils generally
consists of loose to medium dense, dry to slightly moist, brown to reddish brown
silty sand and are considered to have a low expansion potential. Refer to Figure
No. III.
Old Paralic Deposits (Oopo:.Zl;_ The encountered formational materials consist
primarily of medium dense, slightly moist, reddish brown to dark reddish brown,
silty sand. The formational soils were encountered at a depth of approximately
0.25 to 1 feet in all exploratory excavations. The formational soils are considered
to have a low expansion potential. Refer to Figure No. III.
VIII. GEOLOGIC HAZARDS
The following is a discussion of the geologic conditions and hazards common to this
area of the City of Carlsbad, as well as project-specific geologic information relating
to development of the subject property.
Proposed Walnut Avenue Residence Project
Carlsbad, California
A. Local and Regional Faults
Job No. 17-11664
Page 13
Reference to the geologic map of the area (Kennedy and Tan, 2007), Figure No. V,
indicates that no faults are shown to cross the site. In our explicit professional
opinion, neither an active fault nor a potentially active fault underlies the site.
Rose Canyon Fault: The Rose Canyon Fault Zone (Mount Soledad and Rose Canyon
Faults) is located approximately 5 miles southwest of the subject site. The Rose
Canyon Fault is mapped trending north-south from Oceanside to downtown San
Diego, from where it appears to head southward into San Diego Bay, through
Coronado and offshore. The Rose Canyon Fault Zone is considered to be a complex
zone of onshore and offshore, en echelon strike slip, oblique reverse, and oblique
normal faults. The Rose Canyon Fault is considered to be capable of generating an
M7 .2 earthquake and is considered microseismically active, although no significant
recent earthquakes are known to have occurred on the fault.
Investigative work on faults that are part of the Rose Canyon Fault Zone at the
Police Administration and Technical Center in downtown San Diego, at the SDG&E
facility in Rose Canyon, and within San Diego Bay and elsewhere within downtown
San Diego, has encountered offsets in Holocene (geologically recent) sediments.
These findings confirm Holocene displacement on the Rose Canyon Fault, which was
designated an "active" fault in November 1991 (Hart, E.W. and W.A. Bryant, 2007,
Fault-Rupture Hazard Zones in California, California Geological Survey Special
Publication 42).
Coronado Bank Fault: The Coronado Bank Fault is located approximately 21 miles
southwest of the site. Evidence for this fault is based upon geophysical data
(acoustic profiles) and the general alignment of epicenters of recorded seismic
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 14
activity (Greene, 1979). The Oceanside earthquake of M5.3 recorded July 13,
1986, is known to have been centered on the fault or within the Coronado Bank
Fault Zone. Although this fault is considered active, due to the seismicity within the
fault zone, it is significantly less active seismically than the Elsinore Fault (Hileman,
1973). It is postulated that the Coronado Bank Fault is capable of generating a
M7 .6 earthquake and is of great interest due to its close proximity to the greater
San Diego metropolitan area.
Newport-Inglewood Fault: The Newport-Inglewood Fault Zone is located
approximately 5 miles northwest of the site. A significant earthquake (M6.4)
occurred along this fault on March 10, 1933. Since then no additional significant
events have occurred. The fault is believed to have a slip rate of approximately 0.6
mm/yr with an unknown recurrence interval. This fault is believed capable of
producing an earthquake of M6.0 to M7.4 (SCEC, 2004).
Elsinore Fault: The Elsinore Fault is located approximately 25 miles northeast of
the site. The fault extends approximately 200 kilometers (125 miles) from the
Mexican border to the northern end of the Santa Ana Mountains. The Elsinore Fault
zone is a 1-to 4-mile-wide, northwest-southeast-trending zone of discontinuous
and en echelon faults extending through portions of Orange, Riverside, San Diego,
and Imperial Counties. Individual faults within the Elsinore Fault Zone range from
less than 1 mile to 16 miles in length. The trend, length and geomorphic
expression of the Elsinore Fault Zone identify it as being a part of the highly active
San Andreas Fault system.
Like the other faults in the San Andreas system, the Elsinore Fault is a transverse
fault showing predominantly right-lateral movement. According to Hart, et al.
(1979), this movement averages less than 1 centimeter per year. Along most of its
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 15
length, the Elsinore Fault Zone is marked by a bold topographic expression
consisting of linearly aligned ridges, swales and hallows. Faulted Holocene alluvial
deposits (believed to be less than 11,000 years old) found along several segments
of the fault zone suggest that at least part of the zone is currently active.
Although the Elsinore Fault Zone belongs to the San Andreas set of active,
northwest-trending, right-slip faults in the southern California area (Crowell, 1962),
it has not been the site of a major earthquake in historic time, other than a M6.0
earthquake near the town of Elsinore in 1910 (Richter, 1958; Toppozada and Parke,
1982). However, based on length and evidence of late-Pleistocene or Holocene
displacement, Greensfelder (1974) has estimated that the Elsinore Fault Zone is
reasonably capable of generating an earthquake ranging from M6.8 to M7.1.
Faulting evidence exposed in trenches placed in Glen Ivy Marsh across the Glen Ivy
North Fault (a strand of the Elsinore Fault Zone between Corona and Lake Elsinore),
suggest a maximum earthquake recurrence interval of 300 years, and when
combined with previous estimates of the long-term horizontal slip rate of 0.8 to 7 .o
mm/year, suggest typical earthquakes of M6.0 to M7.0 (Rockwell, 1985).
San Jacinto Fault: The San Jacinto Fault is located 4 7 miles to the northeast of the
site. The San Jacinto Fault Zone consists of a series of closely spaced faults,
including the Coyote Creek Fault, that form the western margin of the San Jacinto
Mountains. The fault zone extends from its junction with the San Andreas Fault in
San Bernardino, southeasterly toward the Brawley area, where it continues south of
the international border as the Imperial Transform Fault (Earth Consultants
International [ECI], 2009).
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 16
The San Jacinto Fault zone has a high level of historical seismic activity, with at
least 10 damaging earthquakes (M6.0 to M7.0) having occurred on this fault zone
between 1890 and 1986. Earthquakes on the San Jacinto Fault in 1899 and 1918
caused fatalities in the Riverside County area. Offset across this fault is
predominantly right-lateral, similar to the San Andreas Fault, although some
investigators have suggested that dip-slip motion contributes up to 10% of the net
slip (ECI, 2009).
The segments of the San Jacinto Fault that are of most concern to major
metropolitan areas are the San Bernardino, San Jacinto Valley and Anza segments.
Fault slip rates on the various segments of the San Jacinto are less well constrained
than for the San Andreas Fault, but the available data suggest slip rates of 12 ±6
mm/yr for the northern segments of the fault, and slip rates of 4 ±2 mm/yr for the
southern segments. For large ground-rupturing earthquakes on the San Jacinto
fault, various investigators have suggested a recurrence interval of 150 to 300
years. The Working Group on California Earthquake Probabilities (WGCEP, 2008)
has estimated that there is a 31 percent probability that an earthquake of M6.7 or
greater will occur within 30 years on this fault. Maximum credible earthquakes of
M6.7, M6.9, and M7.2 are expected on the San Bernardino, San Jacinto Valley and
Anza segments, respectively, capable of generating peak horizontal ground
accelerations of 0.48g to 0.53g in the County of Riverside, (ECI, 2009). A MS.4
earthquake occurred on the San Jacinto Fault on July 7, 2010.
The United States Geological Survey has issued the following statements with
respect to the recent seismic activity on southern California faults:
The San Jacinto fault, along with the Elsinore, San Andreas, and other
faults, is part of the plate boundary that accommodates about 2
inches/year of motion as the Pacific plate moves northwest relative to
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 17
the North American plate. The largest recent earthquake on the San
Jacinto fault, near this location, the M6.5 1968 Borrego Mountain
earthquake April 8, 1968, occurred about 25 miles southeast of the
July 7, 2010, M5.4 earthquake.
This M5.4 earthquake follows the 4th of April 2010, Easter Sunday,
M7.2 earthquake, located about 125 miles to the south, well south of
the US Mexico international border. A M4.9 earthquake occurred in
the same area on June 12th at 8:08 pm (Pacific Time). Thus this
section of the San Jacinto fault remains active.
Seismologists are watching two major earthquake faults in southern
California. The San Jacinto fault, the most active earthquake fault in
southern California, extends for more than 100 miles from the
international border into San Bernardino and Riverside, a major
metropolitan area often called the Inland Empire. The Elsinore fault is
more than 110 miles long, and extends into the Orange County and
Los Angeles area as the Whittier fault. The Elsinore fault is capable of
a major earthquake that would significantly affect the large
metropolitan areas of southern California. The Elsinore fault has not
hosted a major earthquake in more than 100 years. The occurrence of
these earthquakes along the San Jacinto fault and continued
aftershocks demonstrates that the earthquake activity in the region
remains at an elevated level. The San Jacinto fault is known as the
most active earthquake fault in southern California. Caltech and USGS
seismologist continue to monitor the ongoing earthquake activity using
the Caltech/USGS Southern California Seismic Network and a GPS
network of more than 100 stations.
B. Other Geologic Hazards
Ground Rupture: Ground rupture is characterized by bedrock slippage along an
established fault and may result in displacement of the ground surface. For ground
rupture to occur along a fault, an earthquake usually exceeds M5.0. If a MS.0
earthquake were to take place on a local fault, an estimated surface-rupture length
1 mile long could be expected (Greensfelder, 1974). Our investigation indicates
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 18
that the subject site is not directly on a known active fault trace and, therefore, the
risk of ground rupture is remote.
Liquefaction: The liquefaction of saturated sands during earthquakes can be a
major cause of damage to buildings. Liquefaction is the process by which soils are
transformed into a viscous fluid that will flow as a liquid when unconfined. It occurs
primarily in loose, saturated sands and silts when they are sufficiently shaken by an
earthquake. On this site, the risk of liquefaction of foundation materials due to
seismic shaking is considered to be low due to the medium dense to dense nature
of the natural-ground material and the lack of a shallow static groundwater surface
under the site. In our opinion, the site does not have a potential for soil strength
loss to occur due to a seismic event.
Tsunami: A tsunami is a series of long waves generated in the ocean by a sudden
displacement of a large volume of water. Underwater earthquakes, landslides,
volcanic eruptions, meteoric impacts, or onshore slope failures can cause this
displacement. Tsunami waves can travel at speeds averaging 450 to 600 miles per
hour. As a tsunami nears the coastline, its speed diminishes, its wave length
decreases, and its height increases greatly. After a major earthquake or other
near-shore tsunami-inducing activity occurs, a tsunami could reach the shore within
a few minutes. One coastal community may experience no damaging waves while
another may experience very destructive waves. Some low-lying areas could
experience severe inland inundation of water and deposition of debris.
Wave heights and run-up elevations from tsunami along the San Diego Coast have
historically fallen within the normal range of the tides (Joy 1968). The largest
tsunami effect recorded in San Diego since 1950 was May 22, 1960, which had a
maximum wave height of 2.1 feet (NOAA, 1993). In this event, 80 meters of dock
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 19
were destroyed and a barge sunk in Quivera Basin. Other tsunamis felt in San
Diego County occurred on November 5, 1952, with a wave height of 2.3 feet caused
by an earthquake in Kamchatka; March 9, 1957, with a wave height of 1.5 feet;
May 22, 1960, at 2.1 feet; March 27, 1964, with a wave height of 3.7 feet and
September 29, 2009, with a wave height of 0.5 feet. It should be noted that
damage does not necessarily occur in direct relationship to wave height, illustrated
by the fact that the damage caused by the 2.1-foot wave height in 1960 was worse
than damage caused by several other tsunamis with higher wave heights.
Historical wave heights and run-up elevations from tsunamis that have impacted
the San Diego Coast have historically fallen within the normal range of the tides
(Joy, 1968). The risk of a tsunami affecting the site is considered moderate as the
site is situated at an elevation of approximately 55 feet above mean sea level and
approximately 1000 feet to an exposed beach. The site is not mapped within a
possible inundation zone on the California Geological Survey's 2009 "Tsunami
Inundation Map for Emergency Planning, Oceanside Quadrangle, San Diego
County."
Geologic Hazards Summary: It is our opinion, based upon a review of the available
maps, our research and our site investigation, that the site is underlain by relatively
stable formational materials and is suited for the for the proposed residential
project and associated improvements provided the recommendations herein are
implemented.
No significant geologic hazards are known to exist on the site that would prevent
the proposed construction. Ground shaking from earthquakes on active southern
California faults and active faults in northwestern Mexico is the greatest geologic
hazard at the property.
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 20
In our explicit professional opinion, no "active" or "potentially active" faults underlie
the project site.
IX. GROUNDWATER
No groundwater was encountered during the course of our field investigation and
we do not anticipate significant groundwater problems to develop in the future, if
the property is developed as proposed and proper drainage is implemented and
maintained. The true groundwater surface is assumed to be at a depth of over 50
feet below the existing and planned building pads. Based on exploratory drilling
throughout San Diego County, we would expect minor seeps between the ground
surface and true water table due to transient "perching" of vadose water on
exceptionally dense, low permeability beds within the formational materials.
It should be kept in mind that any required construction operations will change
surface drainage patterns and/or reduce permeabilities due to the densification of
compacted soils. Such changes of surface and subsurface hydrologic conditions,
plus irrigation of landscaping or significant increases in rainfall, may result in the
appearance of surface or near-surface water at locations where none existed
previously. The damage from such water is expected to be localized and cosmetic
in nature, if good positive drainage is implemented, as recommended in this report,
during and at the completion of construction.
On properties such as the subject site where dense, low permeability soils exist at
shallow depths, even normal landscape irrigation practices on the property or
neighboring properties, or periods of extended rainfall, can result in shallow
"perched" water conditions. The perching (shallow depth) accumulation of water on
a low permeability surface can result in areas of persistent wetting and drowning of
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 21
lawns, plants and trees. Resolution of such conditions, should they occur, may
require site-specific design and construction of subdrain and shallow "wick" drain
dewatering systems.
Subsurface drainage with a properly designed and constructed subdrain system will
be required along with continuous back drainage behind any proposed lower-level
basement walls, property line retaining walls, or any perimeter stem walls for
raised-wood floors where the outside grades are higher than the crawl space
grades. Furthermore, crawl spaces, If used, should be provided with the proper
cross-ventilation to help reduce the potential for moisture-related problems.
Additional recommendations may be required at the time of construction.
It must be understood that unless discovered during site exploration or
encountered during site construction operations, it is extremely difficult to predict if
or where perched or true groundwater conditions may appear in the future. When
site fill or formational soils are fine-grained and of low permeability, water problems
may not become apparent for extended periods of time.
Water conditions, where suspected or encountered during construction, should be
evaluated and remedied by the project civil and geotechnical consultants. The
project developer and property owner, however, must realize that post-construction
appearances of groundwater may have to be dealt with on a site-specific basis.
Proper functional surface drainage should be implemented and maintained at the
property.
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 22
X. CONCLUSIONS AND RECOMMENDATIONS
The following conclusions and recommendations are based upon the practical field
investigation conducted by our firm, and resulting laboratory tests, in conjunction
with our knowledge and experience with similar soils in the Carlsbad area. The
opinions, conclusions, and recommendations presented in this report are contingent
upon Geotechnical Exploration, Inc. being retained to review the final plans and
specifications as they are developed and to observe the site earthwork and
installation of foundations. Accordingly, we recommend that the following
paragraph be included on the grading and foundation plans for the project.
If the geotechnical consultant of record is changed for the project, the
work shall be stopped until the replacement has agreed in writing to
accept the responsibility within their area of technical competence for
approval upon completion of the work. It shall be the responsibility of
the permittee to notify the City Engineer in writing of such change
prior to the recommencement of grading and/or foundation installation
work.
A. Seismic Design Criteria
1. Seismic Design Criteria: Site-specific seismic design criteria for the proposed
residence are presented in the following table in accordance with Section
1613 of the 2016 CBC, which incorporates by reference ASCE 7-10 for
seismic design. We have determined the mapped spectral acceleration
values for the site, based on a latitude of 33.1558 degrees and longitude of -
117.3477 degrees, utilizing a tool provided by the USGS, which provides a
solution for ASCE 7-10 (Section 1613 of the 2016 CBC) utilizing digitized files
for the Spectral Acceleration maps. Based on our experience with similar soil
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 23
conditions, we have assigned a Site Soil Classification of D. Refer to the
"USGS Design Maps Summary Report" presented as Appendix D.
TABLE I
Mapped Spectral Acceleration Values and Design Parameters
s.
1.157 1.037 1.557 1.200
B. Preparation of Soils for Site Development
2. Clearing and Stripping: The existing structures to be demolished, and
vegetation on the lot should be removed prior to the preparation of the
building pad and areas to receive associated improvements. This includes
any roots from existing trees and shrubbery. Holes resulting from the
removal of root systems or other buried obstructions that extend below the
planned grades should be cleared and backfilled with properly compacted fill.
3. Building Pad Surface and Subgrade Preparation: After the building pad has
been cleared, stripped, and the required excavations made to remove the
existing loose or disturbed surface fill, at least the upper 3 feet of pad fill
soils should be removed and recompacted. The bottom of the excavation
shall be extended to expose medium dense to dense formational soils. The
bottom of the excavation should be scarified to a depth of 6 inches, moisture
conditioned, and compacted to the requirements for structural fill.
4. Material for Fill: Existing on-site soils with an organic content of less than 3
percent by volume are, in general, suitable for use as fill. Imported fill
material, where required, should have a low-expansion potential (Expansion
•
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 24
Index of 50 or less per ASTM D4829-ll). In addition, both imported and
existing on-site materials for use as fill should not contain rocks or lumps
more than 6 inches in greatest dimension if the fill soils are compacted with
heavy compaction equipment (or 3 inches in greatest dimension if compacted
with lightweight equipment). All materials for use as fill should be approved
by our representative prior to importing to the site.
5. Expansive Soil Conditions: We do not anticipate that expansive soils will be
encountered during grading. Should such on-site soils be used as fill, they
should be moisture conditioned to at least 5 percent above optimum
moisture content, compacted to 88 to 92 percent. Soils of medium or
greater expansion potential should not be used as retaining wall backfill soils.
If basement slabs are placed directly on medium expansive formational
materials, the moisture content of the soil should be verified to be at least 3
percent above optimum, or scarification and moisture conditioning will be
required.
6. Fill Compaction: All structural fill should be compacted to a minimum degree
of compaction of 90 percent based upon ASTM D1557-12. Fill material
should be spread and compacted in uniform horizontal lifts not exceeding 8
inches in uncompacted thickness. Before compaction begins, the fill should
be brought to a water content that will permit proper compaction by either:
(1) aerating and drying the fill if it is too wet, or (2) moistening the fill with
water if it is too dry. Each lift should be thoroughly mixed before compaction
to ensure a uniform distribution of moisture. For low expansive soils, the
moisture content should be within 2 percent of optimum. We do not
anticipate that medium to highly expansive soils will be encountered on the
site. However, if they are encountered, the moisture content should be at
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 25
least 5 percent over optimum. Once placed, soil moisture content of the fill
soils should be maintained by sprinkling daily. Medium to highly expansive
soils should be compacted to between 88 and 92 percent of Maximum Dry
Density.
The areal extent required to remove the surficial soils should be confirmed by
our representatives during the excavation work based on their examination
of the soils being exposed. The lateral extent of the excavation and
recompaction should be at least 5 feet beyond the edge of the perimeter
ground level foundations of the new residential additions and any areas to
receive exterior improvements where feasible.
If heavy compaction equipment is utilized, oversize material more than 6
inches in diameter should be removed from the fill. If lightweight
compaction equipment is used, oversize material more than 3 inches in
diameter should be removed.
Any rigid improvements founded on the existing surface soils can be
expected to undergo movement and possible damage. Geotechnica/
Exploration, Inc. takes no responsibility for the performance of any
improvements built on loose natural soils or inadequately compacted fills.
Subgrade soils in any exterior area receiving concrete improvements should
be verified for compaction and moisture within 48 hours prior to concrete
placement.
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 26
7.
8.
No uncontrolled fill soils should remain after completion of the site work. In
the event that temporary ramps or pads are constructed of uncontrolled fill
soils, the loose fill soils should be removed and/or recompacted prior to
completion of the grading operation.
Trench and Retaining Wall Backfill: New utility trenches and retaining walls
should be backfilled with imported or on-site low-expansive compacted fill;
gravel is also a suitable backfill material but should be used only if space
constraints will not allow the use of compaction equipment. Gravel can also
be used as backfill around perforated subdrains. All backfill material should
be placed in lift thicknesses appropriate to the type of compaction equipment
utilized and compacted to a minimum degree of compaction of 90 percent by
mechanical means. In pavement areas, that portion of the trench backfill
within the pavement section should conform to the material and compaction
requirements of the adjacent pavement section.
expansion potential fill layer should be maintained
within the building and adjoining exterior slab areas.
In addition, the low-
in utility trench backfill
Our experience has shown that even shallow, narrow trenches (such as for
irrigation and electrical lines) that are not properly compacted can result in
problems, particularly with respect to shallow groundwater accumulation and
migration.
Temporary Slopes: We do not anticipate that significant cut lopes will be
required during grading operations. Based on our subsurface investigation
work, laboratory test results, and engineering analysis, temporary slopes if
required should be stable for a maximum slope height of up to 12 feet and
may be cut at a slope ratio of 0. 75: 1.0 in properly compacted fill soils or
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 27
formational materials. Some localized sloughing or raveling of the soils
exposed on the slopes, however, may occur.
Since the stability of temporary construction slopes will depend largely on the
contractor's activities and safety precautions (storage and equipment
loadings near the tops of cut slopes, surface drainage provisions, etc.), it
should be the contractor's responsibility to establish and maintain all
temporary construction slopes at a safe inclination appropriate to his
methods of operation. No soil stockpiles or surcharge may be placed within a
horizontal distance of 10 feet from the top edge of the excavation.
If these recommendations are not feasible due to space constraints,
temporary shoring may be required for safety and to protect adjacent
property improvements. Similarly, footings near temporary cuts should be
underpinned or protected with shoring.
C. Design Parameters for Proposed Foundations
9. Continuous Footings: Footings for new structures or improvements should
bear on undisturbed formational materials or properly compacted fill soils.
The footings should be founded at least 18 inches below the lowest adjacent
finished grade when founded into properly compacted fill or into formational
material. Footings located adjacent to utility trenches should have their
bearing surfaces situated below an imaginary 1.5: 1.0 plane projected upward
from the bottom edge of the adjacent utility trench.
•
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 28
10. Bearing Values: At the recommended depths, footings on native, medium
dense formational soil or properly compacted fill soil may be designed for
allowable bearing pressures of 2,500 pounds per square foot (psf) for
combined dead and live loads and increased one-third for all loads, including
wind or seismic. The footings should have a minimum width of 12 inches.
11. Footing Reinforcement: All continuous footings should contain top and
bottom reinforcement to provide structural continuity and to permit spanning
of local irregularities. We recommend that a minimum of four No. 5
reinforcing bars be provided in the footings (two at the top and two at the
bottom). Footings over 18 inches in depth should be reinforced as specified
by the structural engineer. A minimum clearance of 3 inches should be
maintained between steel reinforcement and the bottom or sides of the
footing. Isolated square footings should contain, as a minimum, a grid of
three No. 4 steel bars on 12-inch centers, both ways. In order for us to offer
an opinion as to whether the footings are founded on soils of sufficient load
bearing capacity, it is essential that our representative inspect the footing
excavations prior to the placement of reinforcing steel or concrete.
NOTE: The project Civil/Structural Engineer should review all reinforcing
schedules. The reinforcing minimums recommended herein are not to be
construed as structural designs, but merely as minimum reinforcement to
reduce the potential for cracking and separations.
12. Lateral Loads: Lateral load resistance for structure foundations may be
developed in friction between the foundation bottoms and the supporting
subgrade. An allowable friction coefficient of 0.40 is considered applicable.
An additional allowable passive resistance equal to an equivalent fluid weight
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 29
of 300 pcf acting against the new foundations may be used in design
provided the footings are poured neat against the adjacent undisturbed
formational materials and/or properly compacted fill materials. In areas
where existing loose fill soils are present in front of existing or new
foundations (a horizontal distance equal to 3 times the depth of
embedment), the allowable passive resistance should be reduced to 150 pcf
and friction coefficient to 0.35. These lateral resistance values assume a
level surface in front of the footing for a minimum distance of three times the
embedment depth of the footing.
13. Settlement: Settlements under foundations with building loads that comply
with our recommendations are expected to be within tolerable limits for the
proposed additions. For footings designed in accordance with the
recommendations presented in the preceding paragraphs, we anticipate that
total settlements should not exceed 1 inch and that post-construction
differential angular rotation should be less than 1/240.
14. Retaining Walls: Retaining walls must be designed to resist lateral earth
pressures and any additional lateral pressures caused by surcharge loads on
the adjoining retained surface. We recommend that unrestrained
(cantilever) walls with level backfill be designed for an equivalent fluid
pressure of 38 pcf. We recommend that restrained walls (i.e., basement
walls or any walls with angle points that restrain them from rotation) with
level backfill be designed for an equivalent fluid pressure of 56 pcf.
Unrestrained walls with up to 2.0: 1.0 sloping backfills should be designed for
an equivalent fluid pressure of 52 pcf. Restrained walls with up to 2.0: 1.0
sloping backfills should be designed for an equivalent fluid pressure of 76 pcf.
Wherever walls will be subjected to surcharge loads, they should also be
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 30
designed for an additional uniform lateral pressure equal to one-third the
anticipated vertical surcharge pressure in the case of unrestrained walls and
an additional one-half the anticipated vertical surcharge pressure in the case
of restrained walls.
If shoring is required due to limited space constraints, the soil pressure
recommended above remain applicable. For soil passive resistance, see
recommendations listed below.
For seismic design of unrestrained walls, we recommend that the seismic
pressure increment be taken as a fluid pressure distribution utilizing an
equivalent fluid weight of 15 pcf. For restrained walls, we recommend the
seismic pressure increment be waived.
The preceding design pressures assume that the walls are backfilled with low
expansion potential materials (Expansion Index less than 50) and that there
is sufficient drainage behind the walls to prevent the build-up of hydrostatic
pressures from surface water infiltration. We recommend that, in addition to
waterproofing, back drainage be provided by a composite drainage material
such as MiraDrain 6000/6200 or equivalent. The back drain material should
terminate 12 inches below the finish surface where the surface is covered by
slabs or 18 inches below the finish surface in landscape areas.
Waterproofing should continue to 6 inches above top of wall. A subdrain
(such as Total Drain or perforated pipe in an envelope of crushed rock gravel
a maximum of 1 inch in diameter and wrapped with geofabric such as Mirafi
140N), should be placed at the bottom of retaining walls.
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 31
D.
Backfill placed behind the walls should be compacted to a minimum degree of
compaction of 90 percent using light compaction equipment. If heavy
equipment is used, the walls should be appropriately temporarily braced.
Shoring walls, if required, may be designed for the same soil pressure
indicated above. The soldier piles passive resistance may be calculated as
750 pcf times the diameter of the pile, times the depth of embedment of the
pile below the cut surface.
Concrete Slab On-Grade Criteria
Slabs on-grade may only be used on new, properly compacted fill or when bearing
on medium dense natural soils.
15. Minimum Floor Slab Reinforcement: Based on our experience, we have
found that, for various reasons, floor slabs occasionally crack. Therefore, we
recommend that all slabs on-grade contain at least a minimum amount of
reinforcing steel to reduce the separation of cracks, should they occur. Slab
subgrade soil should be verified by a Geotechnical Exploration, Inc.
representative to have the proper moisture content within 48 hours prior to
placement of the vapor barrier and pouring of concrete.
New interior floor slabs should be a minimum of 4 inches actual thickness
and be reinforced with No. 3 bars on 18-inch centers, both ways, placed at
midheight in the slab. Soil moisture content should be kept above the
optimum prior to waterproofing placement under the new concrete slab.
•
• Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 32
Slab subgrade soil should be verified by a Geotechnical Exploration, Inc.
representative to have the proper moisture content within 48 hours prior to
placement of the vapor barrier and pouring of concrete.
16. Slab Moisture Emission: Although it is not the responsibility of geotechnical
engineering firms to provide moisture protection recommendations, as a
service to our clients we provide the following discussion and suggested
minimum protection criteria. Actual recommendations should be provided by
the Project Architect and waterproofing consultants or product manufacturer.
Soil moisture vapor can result in damage to moisture-sensitive floors, some
floor sealers, or sensitive equipment in direct contact with the floor, in
addition to mold and staining on slabs, walls and carpets. The common
practice in Southern California is to place vapor retarders made of PVC, or of
polyethylene. PVC retarders are made in thickness ranging from 10-to 60-
mil. Polyethylene retarders, called visqueen, range from 5-to 10-mil in
thickness. These products are no longer considered adequate for moisture
protection and can actually deteriorate over time.
Specialty vapor retarding and barrier products possess higher tensile
strength and are more specifically designed for and intended to retard
moisture transmission into and through concrete slabs. The use of such
products is highly recommended for reduction of floor slab moisture
emission.
The following American Society for Testing and Materials (ASTM) and
American Concrete Institute (ACI) sections address the issue of moisture
transmission into and through concrete slabs: ASTM E1745-97 (2009)
•
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 33
Standard Specification for Plastic Water Vapor Retarders Used in Contact
Concrete Slabs; ASTM E154-88 (2005) Standard Test Methods for Water
Vapor Retarders Used in Contact with Earth; ASTM E96-95 Standard Test
Methods for Water Vapor Transmission of Materials; ASTM E1643-98 (2009)
Standard Practice for Installation of Water Vapor Retarders Used in Contact
Under Concrete Slabs; and ACI 302.2R-06 Guide for Concrete Slabs that
Receive Moisture-Sensitive Flooring Materials.
16.1 Based on the above, we recommend that the vapor barrier consist of a
minimum 15-mil extruded polyolefin plastic (no recycled content or
woven materials permitted). Permeance as tested before and after
mandatory conditioning (ASTM E1745 Section 7.1 and subparagraphs
7.1.1-7.1.5) should be less than 0.01 perms (grains/square
foot/hour/per inch of Mercury) and comply with the ASTM E1745 Class
A requirements. Installation of vapor barriers should be in accordance
with ASTM E1643. The basis of design is 15-mil StegoWrap vapor
barrier placed per the manufacturer's guidelines. Reef Industries
Vapor Guard membrane has also been shown to achieve a permeance
of less than 0.01 perms. We recommend that the slab be poured
directly on the vapor barrier, which is placed directly on the prepared
subgrade soil.
16.2 Common to all acceptable products, vapor retarder/barrier joints must
be lapped and sealed with mastic or the manufacturer's recommended
tape or sealing products. In actual practice, stakes are often driven
through the retarder material, equipment is dragged or rolled across
the retarder, overlapping or jointing is not properly implemented, etc.
All these construction deficiencies reduce the retarder's effectiveness.
t
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 34
In no case should retarder/barrier products be punctured or gaps be
allowed to form prior to or during concrete placement.
16.3 Vapor retarders/barriers do not provide full waterproofing for
structures constructed below free water surfaces. They are intended
to help reduce or prevent vapor transmission and/or capillary
migration through the soil and through the concrete slabs.
Waterproofing systems must be designed and properly constructed if
full waterproofing is desired. The owner and project designers should
be consulted to determine the specific level of protection required.
16.4 Following placement of any concrete floor slabs, sufficient drying time
must be allowed prior to placement of floor coverings. Premature
placement of floor coverings may result in degradation of adhesive
materials and loosening of the finish floor materials.
17. Concrete Isolation Joints: We recommend the project Civil/Structural
Engineer incorporate isolation joints and sawcuts to at least one-fourth the
thickness of the slab in any floor designs. The joints and cuts, if properly
placed, should reduce the potential for and help control floor slab cracking.
We recommend that concrete shrinkage joints be spaced no farther than
approximately 20 feet apart, and also at re-entrant corners. However, due
to a number of reasons (such as base preparation, construction techniques,
curing procedures, and normal shrinkage of concrete), some cracking of
slabs can be expected. Structural slabs should not be provided with control
joints.
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 35
18. Exterior Slab Reinforcement: Exterior concrete slabs should be at least 4
inches thick. As a minimum for protection of on-site improvements, we
recommend that all nonstructural concrete slabs (such as patios, sidewalks,
etc.), be founded on properly compacted and tested fill or medium dense
native formation and be underlain (if needed) by 2 inches and no more than
3 inches of clean leveling sand, with No. 3 bars at 18-inch centers, both
ways, at the center of the slab. Exterior slabs should contain adequate
isolation and control joints.
The performance of on-site improvements can be greatly affected by soil
base preparation and the quality of construction. It is therefore important
that all improvements are properly designed and constructed for the existing
soil conditions. The improvements should not be built on loose soils or fills
placed without our observation and testing. The subgrade of exterior
improvements should be verified as properly prepared within 48 hours prior
to concrete placement. A minimum thickness of 3 feet of properly
recompacted soils should underlie the exterior slabs on-grade or they should
be constructed on dense formational soils.
For exterior slabs with the minimum shrinkage reinforcement, control joints
should be placed at spaces no farther than 15 feet apart or the width of the
slab, whichever is less, and also at re-entrant corners. Control and isolation
joints in exterior slabs should be sealed with elastomeric joint sealant. The
sealant should be inspected every 6 months and be properly maintained.
Proposed Walnut Avenue Residence Project
Carlsbad, California
E. Site Drainage Considerations
Job No. 17-11664
Page 36
19. Erosion Control: Appropriate erosion control measures should be taken at all
times during and after construction to prevent surface runoff waters from
entering footing excavations or ponding on finished building pad areas.
20. Surface Drainage: Adequate measures should be taken to properly finish-
grade the lot after the structures and other improvements are in place.
Drainage waters from this site and adjacent properties should be directed
away from the footings, floor slabs, and slopes, onto the natural drainage
direction for this area or into properly designed and approved drainage
facilities provided by the project civil engineer. Roof gutters and downspouts
should be installed on the residence, with the runoff directed away from the
foundations via closed drainage lines. Proper subsurface and surface
drainage will help minimize the potential for waters to seek the level of the
bearing soils under the footings and floor slabs.
Failure to observe this recommendation could result in undermining and
possible differential settlement of the structure or other improvements on the
site or cause other moisture-related problems. Currently, the CBC requires a
minimum 1-percent surface gradient for proper drainage of building pads
unless waived by the building official. Concrete pavement may have a
minimum gradient of 0.5-percent.
21. Planter Drainage: Planter areas, flower beds and planter boxes should be
sloped to drain away from the footings and floor slabs at a gradient of at
least 5 percent within 5 feet from the perimeter walls. Any planter areas
adjacent to the residence or surrounded by concrete improvements should be
•
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 37
provided with sufficient area drains to help with rapid runoff disposal. No
water should be allowed to pond adjacent to the residence or other
improvements or anywhere on the site.
F. General Recommendations
22. Proiect Start Up Notification: In order to reduce work delays during site
development, this firm should be contacted 48 hours prior to any need for
observation of footing excavations or field density testing of compacted fill
soils. If possible, placement of formwork and steel reinforcement in footing
excavations should not occur prior to observing the excavations; in the event
that our observations reveal the need for deepening or redesigning
foundation structures at any locations, any formwork or steel reinforcement
in the affected footing excavation areas would have to be removed prior to
correction of the observed problem (i.e., deepening the footing excavation,
recompacting soil in the bottom of the excavation, etc.).
23. Construction Best Management Practices (BMPs): Construction BMPs must
be implemented in accordance with the requirements of the controlling
jurisdiction. Sufficient BMPs must be installed to prevent silt, mud or other
construction debris from being tracked into the adjacent street(s) or storm
water conveyance systems due to construction vehicles or any other
construction activity. The contractor is responsible for cleaning any such
debris that may be in the street at the end of each work day or after a storm
event that causes breach in the installed construction BMPs.
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 38
All stockpiles of uncompacted soil and/or building materials that are intended
to be le~ unprotected for a period greater than 7 days are to be provided
with erosion and sediment controls. Such soil must be protected each day
when the probability of rain is 40% or greater. A concrete washout should
be provided on all projects that propose the construction of any concrete
improvements that are to be poured in place. All erosion/sediment control
devices should be maintained in working order at all times. All slopes that
are created or disturbed by construction activity must be protected against
erosion and sediment transport at all times. The storage of all construction
materials and equipment must be protected against any potential release of
pollutants into the environment.
XI. GRADING NOTES
Geotechnica/ Exploration, Inc. recommends that we be retained to verify the
actual soil conditions revealed during site grading work and footing excavation to be
as anticipated in this "Report of Preliminary Geotechnical Investigation" for the
project. In addition, the placement and compaction of any fill or backfill soils
during site grading work must be observed and tested by the soil engineer.
It is the responsibility of the grading contractor to comply with the requirements on
the grading plans as well as the local grading ordinance. All retaining wall and
trench backfill should be properly compacted. Geotechnical Exploration, Inc.
will assume no liability for damage occurring due to improperly or uncompacted
backfill placed without our observations and testing.
Proposed Walnut Avenue Residence Project
Carlsbad, California
XII. LIMITATIONS
Job No. 17-11664
Page 39
Our conclusions and recommendations have been based on available data obtained
from our field investigation and laboratory analysis, as well as our experience with
similar soils and formational materials located in this area of Encinitas. Of
necessity, we must assume a certain degree of continuity between exploratory
excavations and/or natural exposures. It is, therefore, necessary that all
observations, conclusions, and recommendations be verified at the time grading
operations begin or when footing excavations are placed. In the event
discrepancies are noted, additional recommendations may be issued, if required.
The work performed and recommendations presented herein are the result of an
investigation and analysis that meet the contemporary standard of care in our
profession within the County of San Diego. No warranty is provided.
As stated previously, it is not within the scope of our services to provide quality
control oversight for surface or subsurface drainage construction or retaining wall
sealing and base of wall drain construction. It is the responsibility of the contractor
to verify proper wall sealing, geofabric installation, protection board installation (if
needed), drain depth below interior floor or yard surfaces, pipe percent slope to the
outlet, etc.
This report should be considered valid for a period of two (2) years, and is subject
to review by our firm following that time. If significant modifications are made to
the building plans, especially with respect to the height and location of any
proposed structures, this report must be presented to us for immediate review and
possible revision.
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 40
If the geotechnical consultant of record is changed, work shall be stopped until the
replacement has agreed in writing to accept the responsibility within their area of
technical competence upon completion of the work. It shall be the responsibility of
the permittee to notify the governing agency in writing of such change prior to the
commencement or recommencement of grading and/or foundation installation
work.
It is the responsibility of the owner and/or developer to ensure that the
recommendations summarized in this report are carried out in the field operations
and that our recommendations for design of this project are incorporated in the
grading and structural plans. We should be retained to review the project plans
once they are available, to verify that our recommendations are adequately
incorporated in the plans. Additional or modified recommendations may be issued
if warranted after plan review.
This firm does not practice or consult in the field of safety engineering. We do not
direct the contractor's operations, and we cannot be responsible for the safety of
personnel other than our own on the site; the safety of others is the responsibility
of the contractor. The contractor should notify the owner if any of the
recommended actions presented herein are considered to be unsafe.
The firm of Geotec:hnical Exploration, Inc:. shall not be held responsible for
changes to the physical condition of the property, such as addition of fill soils or
changing drainage patterns, which occur subsequent to issuance of this report and
the changes are made without our observations, testing, and approval.
Proposed Walnut Avenue Residence Project
Carlsbad, California
Job No. 17-11664
Page 41
Once again, should any questions arise concerning this report, please feel free to
contact the undersigned. Reference to our Job No. 17-11664 will expedite a reply
to your inquiries.
Respectfully submitted,
GEOTECHNICAL EXPLORATION, INC.
Jaime A. Cerros, P.E.
R.C.E. 34422/G.E. 2007
Senior Geotechnical Engineer
Jonat n . Browning
P.G. 01 C.E.G. 2615
Le 1e D. Reed, President
C.E.G. 999/P.G. 3391
-/4_,otW..~o t'l:f~ ~r;,'-IE 0. /1~ ~~
1.ff "No. 999 o ~
: A-Exp. 3/311./2 * f
\ CEllTIFIED ;;
1~ ENGINEERING. :it° , -,, G l:OLOGIST .;;f, '· .,.~ . ..__.,. ..... ·-...._ o,_. CAL If~·
..... ..___._. -
----------
VICINITY MAP
Rincon Walnut Avenue Project
362 Walnut Avenue
Carlsbad, CA.
Figure No. I
Job No. 17-11664
31
LU ::, z ~ ... :,
2 .., ;
17-11664-p.si
'Jf:JUf
~ --------------7 ~ -------------------------------~------------------,-------
Jl ;~
I
I
1
I
I
I
I
r
! OORY II ----------~ JI
I
L
1
I
I
i
I
I
I
I
I
I
I
!
I
I
I
I
I
I
I
I I
I I
18'~
I I I I I I I I
I
I I
I I
l
I 10'--0'
.
UNIT1 nl 2,284 S.F C7 3BEDROOM
HP-4 2STORY
39'-4' --J'lL----------f
k
'
.
VllllllR PMKNG
UNfT2 1,876S.F.
2BEDROCM
3STORY
UNIT3
1,875S.F
3BEOROOM 3STORY
-r.=~===.;;::::====IT-----~ Ii. 11 :,;----------:;·Jr I •A• ll -.
UNIT4 ,.,..
11'--0'
~
HP-2
--
1,875 S.F. 318,B lM. 2BEDROOM
3 STORY 3 STAJ-1 ,
11=!!=====!!::::====r.~~ '-= '--I
24'-8' 24'-8" t. -~l~~------,,,r--1,,
h~=====;;=1
===T,,,_9· ~~
I
!'•' L, c-
20'--0'
RY.$.B.
0 ~ INF-2
1 ~ F.Y .S.B. UNIT 11 ! 1 , 1,875 S.F
HP-5 11'-0' UNIT 10 ~ ~ UNIT9 UNIT3 ~ 11'-0' UNIT7 UNITS 1,875 S.F. 3BEDROOM
I
2BEDROOM L==::;i 3STORY
1,875 S.F 3BEDROOM
3STORY
: EIIIRY II
L ____ J.!:====::::!!::====
•
Ir Ell1l!Y -IIH
---··-. -------
~75S.F. 75S.F. 1,875$.F 2 EDROOM CROOM 3BEDROOM 3STORY 'TORY 3STORY -11 II -3 Dml'f I ----------------
3 STORY I [ £ll1lll'
_b~=!!:::======L-----~INF-1
L ________________________________________ _
I ---''"1.-----------------7
NOTE: This Plot Plan is not to be used for legal purposes,
Locations and dimensions are approximate. Actual
property dimensions and locations of utilities may be
obtained from the Approved Building Plans or the
"As-Built" Grading Plans.
REFERENCE: This Plot Plan was prepared from an existing
undated CONCEPTUAL SITE PLAN provided by the client
and from on-site field reconnaissance performed by GEi.
'
I
I
I
Scale: 1" = 20'
( approximate)
LEGEND
~
HP-5
G.l INF-1
Approximate Location
of Exploratory Handpit
Approximate Location of
Infiltration Test
PLOT PLAN
Rincon Walnut Avenue Project
362 Walnut Avenue
Carlsbad, CA.
Figure No. II
Job No. 17-11664
DI Geotechnical Exploration, Inc.
~ ( November 2017)
....
;ii ~
t:i CJ ...I a. X w
0 w CJ
ii'. CJ
r EQUIPMENT DIMENSION & TYPE OF EXCAVATION
Hand Tools 2' X 2' X 3' Handpit
SURFACE ELEVATION GROUNDWATER/ SEEPAGE DEPTH
:t 55' Mean Sea Level Not Encountered
-
1 -
-
-
2 -
-
-
-
3 -
-
-
-
4 -
-
-
-
FIELD DESCRIPTION
AND
CLASSIFICATION
..... w g ~ DESCRIPTION AND REMARKS
~ ~ (Grain size, Density, M?lsture, Color)
-
IX
I
SILTY SAND. Loose. Dry. Brown.
TOPSOIL
SILTY SAND, fine-to medium-grained, trace
manganese nodules. Medium dense. Slightly
moist. Dark red-brown.
OLD PARALIC DEPOSITS (Qop s-7)
Bulk bag sample from 2'-3'.
Bottom @3'
(/)
c..5 (/)
:;j
SM
SM
DATE LOGGED "
10-16-17
LOGGED BY
JAB
~
>-c-~ ~'t;' ~ ~ ~o ~ d w a o.
:::!:~
a o. d d _ w~ ~f :::!:~ ~q t d ::,~ u, W U> u::, ::,~ z I-....I W 5 t; 5 cn :::.--::!: ~ u, -u, w_ ~ CJ) :s:;z a.. :c
~5 a..Z I-0 i~ zo z 05 :::!:U . w 15 :::. w ;ie ~ 0 u)S, _::;; ~a a ~ (.) a5 (.)
8.2 130.8
3.8 105.6
'3'-----'---1......1-------------------'---'---_.__ _ _..__ ......... __ ..._____._ ____ ......___,
z ~ z ~ ii'.
I
g
z 0 I ~ w "
y_
~
[TI
•
0
t?il
PERCHED WATER TABLE
BULK BAG SAMPLE
IN-PLACE SAMPLE
MODIFIED CALIFORNIA SAMPLE
NUCLEAR FIELD DENSITY TEST
STANDARD PENETRATION TEST
JOB NAME
Rincon -Walnut Avenue Project
SITE LOCATION
362 Walnut Avenue, Carlsbad, CA
JOB NUMBER REVIEWED BY LOR/JAC LOG No.
17-11664 tr;t---HP-1 FIGURE NUWBER Ellplor.Uon, Inc.
Illa ~ ~
I' EQUIPMENT DIMENSION & TYPE OF EXCAVATION DATE LOGGED
Hand Tools 2' X 2' X 2.5' Handpit 10-16-17
SURFACE ELEVATION GROUNDWATER/ SEEPAGE DEPTH LOGGED BY
± 55' Mean Sea Level Not Encountered JAB
FIELD DESCRIPTION l AND ~ >-'u C ~& ci I CLASSIFICATION w~ 15.e, ::::d~ ci i-: o_
...J ~~ ::;-i!:q +_ d ~ w cti u::, ~~ ::,~ W(I) :r 0 ~ DESCRIPTION AND REMARKS 5~ 5 ci5 ~ ci5 -::!! ~ (/) 3:: 'z ...JW ,_ 00 (J ~o CL ::i:; ~ ~ ! (Grain size, Density, Moisture, Color) cti o,.-o,.z ,_ 0 ~~ ~8 o=> i~ ::::i :!!:~ z UJ ~:!, ~~ ffi8 _Q
it~\} SILTY SAND. Loose. Dry. Brown. SM
-r\ TOPSOIL / SM
-SIL TY SAND , fine-to medium-grained, some
roots to 1/2" in diameter. Medium dense. Slightly
moist. Red-brown. -
1 -OLD PARALIC DEPOSITS (Qop s.7)
-
-
-
-
2-I -3.7 107.8
-
-
3 -Bottom @ 2.5'
-
-
-
4 -
-
-
-
~ JOB NAM: PERCHED WATER TABLE Rincon -Walnut Avenue Project
[g1 BULK BAG SAMPLE SITE LOCATION
[I] IN-PLACE SAMPLE 362 Walnut Avenue, Carlsbad , CA
• MODIFIED CALIFORNIA SAMPLE JOB NUMBER REVIEWED BY LDR/JAC LOG No.
0 NUCLEAR FIELD DENSITY TEST 17-11664 ;;·-· HP-2 FIGURE NUMBER Exploratlon. Inc.
~ STANDARD PENETRATION TEST lllb ~ ~ '"
§
..J :,>; w
0 w {!)
fu ... ::,
i z 8 z a:
i
§
z 0 i ~
,, EQUIPtvf:NT DIMENSION & TYPE OF EXCAVATION DATE LOGGED
Hand Tools 2' X 2' X 2.5' Handpit 10-16-17
SURFACE ELEVATION GROUNDWATER/ SEEPAGE DEPTH LOGGED BY
± 55' Mean Sea Level Not Encountered JAB
FIELD DESCRIPTION
AND ~ >-c-~ ~i ~ CLASSIFICATION 25~ UJ UJ g UJ c:: t'31:: :;; c:: :;;-...J UJ (..)~ ::, ::, j~ :i:: 0 ~ DESCRIPTION AND REMARKS en 5m :;; ,-.. ,-.. a:, (..) 500 -oo -00 a.. ~ ~ (Grain size, Density. Moisture, Color) en 0,.5 a..z ~~ i~ UJ 'W 0 00 00 ::i ~:;; ~o
~!~ SILTY SAND. Loose. Dry. Brown. SM
TOPSOIL
-SILTY SAND , fine-to medium-grained. Medium SM
-dense. Slightly moist. Red-brown.
1 -OLD PARALIC DEPOSITS (Qop d
-
-
-
2 -,.,__,.
-3.8 102.8 .
-
.
-
3 -Bottom @ 2.5'
-
-
-
4 -
-
-
-
,!: PERCHED WATER TABLE JOB NAME
Rincon -Walnut Avenue Project
~ BULK BAG SAMPLE SITE LOCATION
m IN-PLACE SAMPLE 362 Walnut Avenue, Carlsbad, CA
• MODIFIED CALIFORNIA SAMPLE JOB NUMBER REVIEWED BY LDR/JAC
0 NUCLEAR FIELD DENSITY TEST 17-11664 Cli-lji ...,_ .. , FIGURE NUMBER Ellploratlon, Inc.
~ STANDARD PENETRATION TEST Ille ~ \,.
-.._
~
ci ti; ci d ~q + _j 00 w<n -::::i: § 0 ,-.. ~UJ oo_ 00 3:z ~~ zo z o=> ~~ 0 _,a (.) a:,(.) ooc-
LOG No,
HP-3
~
r-
$
8 ...J 0. )( w
0 w (!)
0: (!)
r EQUIPMENT DIMENSION & TYPE OF EXCAVATION
Hand Tools 2' X 2' X 3' Handpit
SURFACE ELEVATION GROUNDWATER/ SEEPAGE DEPTH
± 54' Mean Sea Level Not Encountered
~ ~ ...J :c 0 I-co c.. ~ w 0 rn
-
1 -
-
-
2 -
-
-
3 -
-
-
-
4 -
-
-
-
FIELD DESCRIPTION
AND
CLASSIFICATION
w ...J c.. :::. ~
<Ji DESCRIPTION AND REMARKS (..)
(Grain size, Density, Moisture, Color) ul ::i
SILTY SAND. Loose. Dry. Brown. SM
1 FILL (Qaf) t"-SM-~ --------------------
I
SIL TY SAND, fine-to medium-grained. Medium
dense. Dry to slightly moist. Brown.
FILL (Qaf)
SIL TY SAND , fine-to medium-grained. Medium
dense. Slightly moist. Red-brown.
OLD PARALIC DEPOSITS (Qop d
Bottom @3'
SM
DATE LOGGED '
10-16-17
LOGGED BY
JAB
l ~ &-=-l ~& c:i
UJ 0 ~ UJ c:i i--: o_ :::.-+ I!,, UJ o:'. tj ~ :!:o:'. => ~ ~q ·d rn w rn <.) => :::,~ :st:, ::S en ::. --:::. ~ rn ~~ Ir UJ ~rn -rn "'-~~ q.-c..z ~~ §~ zo ?5 8 o :::> ~~ ::z W ~~ _,o _o co <.) "'=
3.8 105.0
t::;,___....__..._.__ __________________ ....... _...___...__ _ ___. _ ___...__ _ _.__ ...... _ ___. _ ___...__~
z i z 8 z ii:
i
(!) g
z 0 .:: ~ 0 ~ w \..
_y
(g]
[I]
•
0
fd:]
PERCHED WATER TABLE
BULK BAG SAMPLE
IN-PLACE SAMPLE
MODIFIED CALIFORNIA SAMPLE
NUCLEAR FIELD DENSITY TEST
STANDARD PENETRATION TEST
JOB NAME
Rincon -Walnut Avenue Project
SITE LOCATION
362 Walnut Avenue, Carlsbad, CA
JOB NUMBER REVIEWED BY LDR/JAC LOG No.
17-11664 4r,;& ---~ HP-4 FIGURE NUMBER Exploration, Inc.
llld ~ ~
~
i ,...
0 C)
~
0 ~
~ a. (!)
r EQUIPMENT DIMENSION & TYPE OF EXCAVATION
Hand Tools 2' X 2' X 3' Handpit
SURFACE ELEVATION GROUNDWATER/ SEEPAGE DEPTH
± 55' Mean Sea Level Not Encountered
-
1 -
-
-
-
2 -
-
-
-
-
-
3 -
-
-
-
-
4 -
-
-
-
-
---' 0 CD ~
FIELD DESCRIPTION
AND
CLASSIFICATION
w ---' DESCRIPTION AND REMARKS Cl.. ~ (Grain size, Density, Moisture, Color)
SIL TY SAND. Loose. Dry. Brown.
\ TOPSOIL
-
IX
I
SIL TY SAND , fine-to medium-grained, trace
roots to 3/8" in diameter. Medium dense to dense.
Slightly moist. Dark red-brown.
OLD PARALIC DEPOSITS (Qop d
Bulk bag sample from 2'-3'.
-19% passing #200 sieve.
Bottom@3'
<J)
<.5 <J)
::i
SM
{SM
DATE LOGGED "
10-16-17
LOGGED BY
JAB
~ C it:= C ~'[ d w a~ ::. lli! d ~ d WC:: ~~ ::i;-fC! +
5~ :::) :::) =>f . cl en woo
3:~ ---' uJ :s 1il ::.;1-~ (/) (/)::. ~ !Q Cl.. :I:
'""15 Cl...Z t5 ~z z'15 ~8 o :::J i~ 'L1J ~c _.o ~::;; ~a o::. ::;;~ CD U
4.6 111 .1
5..._ _ _.___..._. __________________ .......__......__...__........_ _ __._ __ ...____. __ ....._ _ _._____.
z ~ z 0 ~ ii
i
§
z 0
I '-
~
~
ill
•
0
~
PERCHED WATER TABLE
BULK BAG SAMPLE
IN-PLACE SAMPLE
MODIFIED CALIFORNIA SAMPLE
NUCLEAR FIELD DENSITY TEST
STANDARD PENETRATION TEST
JOB NAME
Rincon -Walnut Avenue Project
SITE LOCATION
362 Walnut Avenue, Carlsbad, CA
JOB NUMBER REVIEWED BY LDR/JAC LOGNo.
17-11664 er.Ii•-~ HP-5 FIGURE NUMBER Elrploratlon, Inc.
Ille ~ ~
•
135 \
\ \
\ \
\ \
130
.... , \ \
/" ' \ \
I ' \ • \\ \ ,
\ '
125
~ \
1 \ \
~\ 1 Source of Material HP-1 @2.0'
\ \
\ \ Description of Material SIL TY SAND {SM}, Brown
120 \
\ \ Test Method ASTM 01557 Method A
\ \
\ \
\
115 \ \
\
\ \ TEST RESULTS \ 1
\ \ Maximum Dry Density 130.8 PCF
110 \ \ ' Optimum Water Content __g % \ \
'ti \ \
a. \ \ ~ ~ Expansion Index (El)
\ \ --
ii5 \ \ \ z 105 UJ \ \ I. Cl >-\ \
0:: \ \ Cl
I\ \ '
100
\ \.
I\ \ I\ Curves of 100% Saturation
s;;: ' for Specific Gravity Equal to: '\ r-I\.
\ \ 2.80
95 C
\ ' \ \. 2.70
\ \ \
'\. ' 2.60
\ \ \.
90 '\. \
\. '\ ...
'\. '\. ' I'\ '\
\. ' ~
85 '\. ~
"-' ~
" '\. ...
\. '\
\ ' "
80 ' "' ...
' "' ...
'-' ....
" " I
" 'I
75 "-
0 5 10 15 20 25 30 35 40 45
WATER CONTENT,%
41"i= Geotechnical MOISTURE-DENSITY RELATIONSHIP
Exploration, Inc. Figure Number: IV
~
Job Name: Rincon -Walnut Avenue Project
Site Location: 362 Walnut Avenue, Carlsbad, CA
Job Number: 17-11664
Ocean
e ....... ,
OrMt'Otl ban l"W900'•~~·,. ty;'l,(9'...,., ra tl~_...,,.J 'to-,, U$G':> W,111 W ~ti iCllJ)
dN, S,,, 0-ttO Yr r 0G' intt,11: ~olf"lille St-=~
ti,o;q'~f'-CtNUel~USGS ~.g~ ...... ._nol.ln
{OE\111 O-.r.~• t.M~rr. C'OI\IO.lf1 .,11 th1:,: l;lflll~tf"'CVJ fl'Otn NOAA 1,,r;te r4 ~ Get.I
~"itrM ...,.1I No,il11\1rOU,,c.tt,,.\lll,1f
T)Qr,,ip-\lode:t1>:.":b~IMUS GvlOCjlcAI
&.;1\-.f ...... IO"I. C:000. ...... f GoaoQoc ~ Pru\)in'l s-A.,.EMAPJ!lwllr:l" nc.. N-4CACio4V
~~"~r.lOl'l,...,,..u.s ~151.-..., Soi.~•-,cub-:w.1v1aM.io~Picf,td
~11~.f'JOlo,,lhlC1-0'1U10.~11'rclllG+'CClr1"'1,:,n
Mrtgrq,'""11.., "olOt»ll~ltwoublk•IIMllf' .. ,w,r.i~
_...,.,,w,wi,,.~1111fJlneOP't"-wG•.:.10gd~
111to,:.;,r.,,d~IH)•l'IC-lil., .... 11r,
IIJt.l~~of.,,,.l p,oducllol".,,,.po",1'tc&rll''Jr;w)tl
Rincon-362-2008-0C-geo.ai
Rincon Walnut Avenue Projec t
362 Walnut Avenue
Carlsbad, CA.
EXCERPT FROM GEOLOGIC MAP OF THE OCEANSIDE 30' x 60' QUADRANGLE, CALIFORNIA
Compiled by
~o u --"5"--
--.
-1!
" ......
Ell
-2.
+
..
..,._
~
•-
Michael P. Kennedy1 and Siang S. Tan1
2007
Digital preparation by
Kelly R. Bovard", Rachel M. Alvarez', Michael J. watson', and Carlos I. Gutierrez'
1, O.a1nN•~~°"""""93-0lll'al...,,_,
l ~ Ck:it;,i;~s,..r,., C-r.,..nd!wthS.-~•~ ~
ONSHORE MAP SYMBOLS DESCRIPTION OF MAP UNITS
Fllllt -Solid l\'Mrt ~· loca.l;d; ashed ~hffl:, apprmirr.11ely locr.ed; dau"6 wh:tt
""""1,<l U -uplbluNu b1oa. D • _, bloc\. /on<# 111d rur.b<r inmwr
<lrtctitrl and 11\g)< or dip of l'iol plw.
Lari.thlld~Ar?'C'Wli ind:iutc p.i:lcipal dirmcm of u-,ycnwrL Queried v,fart cxisttlliZC 11
q!151icrahie.
Strlk• ,nd dip of b«ta
Jndlntd
Onrturntd
v~rtk.al
Borl:mnt.11
Strike •rld dip of lgneout foU•tioD
lndlntd
Vtf'tkaJ
SCrlkund dip of !p,ovt Jolnta
Indln<d ,,., ....
Strlk.e and dtp ermet:amorpbl,c foUatlon
LD<tinod
Strtl&a •nd d.tp or~t.UJ jotntl
v,r1Ju1
Units 6-7 Old paralic deposits, undivided
Figure No. V
Job No. 17-11664 ~~=•--~ November 2017
APPENDIX A
UNIFIED SOIL CLASSIFICATION CHART
SOIL DESCRIPTION
Coarse-grained (More than half of material is larger than a No. 200 sieve)
GRAVELS, CLEAN GRAVELS
(More than half of coarse fraction
is larger than No. 4 sieve size, but
smaller than 3")
GRAVELS WITH FINES
(Appreciable amount)
SANDS, CLEAN SANDS
(More than half of coarse fraction
is smaller than a No. 4 sieve)
SANDS WITH FINES
(Appreciable amount)
GW
GP
GC
SW
SP
SM
Well-graded gravels, gravel and sand mixtures, little
or no fines.
Poorly graded gravels, gravel and sand mixtures, little
or no fines.
Clay gravels, poorly graded gravel-sand-silt mixtures
Well-graded sand, gravelly sands, little or no fines
Poorly graded sands, gravelly sands, little or no fines.
Silty sands, poorly graded sand and silty mixtures.
SC Clayey sands, poorly graded sand and clay mixtures.
Fine-grained (More than half of material is smaller than a No. 200 sieve)
SILTS AND CLAYS
Liquid Limit Less than 50
Liquid Limit Greater than 50
HIGHLY ORGANIC SOILS
ML Inorganic silts and very fine sands, rock flour, sandy
silt and clayey-silt sand mixtures with a slight plasticity
CL Inorganic clays of low to medium plasticity, gravelly
clays, silty clays, clean clays.
OL Organic silts and organic silty clays of low plasticity.
MH Inorganic silts, micaceous or diatomaceous fine sandy
or silty soils, elastic silts.
CH Inorganic clays of high plasticity, fat clays.
OH Organic clays of medium to high plasticity.
PT Peat and other highly organic soils
APPENDIXB
INFILTRATION TEST DATA AND INFILTRATION
RATE CALCULATIONS
Simple Open Pit Falling Head Test Sheet
Project Name: Rincon Walnut Ave Project
Project No. 17-11664
Date Excavated: 10/16/17
Test Hole No: INF-1
Initial Time (Minutes) Final Time (Minutes)
955 1025
1025 1110
1115 1215
Time interval
(minutes)
30
45
60
Initial Water Level
(inches)
30.000
30.000
30.000
Tested By: JAB
Soil aassification: SM
Depth of Test Hole: 36"
Test Hole Dia: 24"
Final Water Level
Cinches)
36.000
36.000
36.000
Change In water
(inches)
6.000
6.000
6.000
Falling Head Rate
(min/Inches)
5.000
7.500
10.000
•
Simple Open Pit Falling Head Test Sheet
Project Name: Rincon Walnut Ave Project
Project No. 17-11664
Date Excavated: 10/16/17
Test Hole No: INF-2
Initial Time (Minutes) Final Time (Minutes)
1000 1020
1022 1107
1107 1207
Time Interval
(minutes)
20
45
60
Initial Water level
(inches)
30.500
30.000
30.000
Tested By: JAB
Soil Classification: SM
Depth of Test Hole: 36.5"
Test Hole Dia: 2411
Final Water level
(inches)
36.500
36.500
36.500
Change in water
(inches)
6.000
6.500
6.500
Falling Head Rate
(min/inches)
3.333
6.923
9.231
Simple Open Pit Rate to Infiltration Rate Conversion (Porchet Method)
Project Name: Rincon Walnut Ave Project
Project No. 17-11664
Test Hole No: INF-1
Test EB Depth Delta T Water Depth
No. (inches) (min) 1 (inches)
1 36 30 30.000
2 36 45 30.000
3 36 60 30.000
4
5
6
7
8
9
Calculated By: JAB
Checked By:
Test Hole Dia: 24"
Date: 10/17/2017
Date:
Depth of Test Hole: 36"
Porchet Corrections
Infiltrat ion rate=((delta h*60r}/(delta t*(r+2 h avg})
Water Depth hl h2 delta h havg
2 (inches) (inches) (inches) (inches) (inches)
36.000 6.000 0.000 6.000 3.000
36.000 6.000 0.000 6.000 3.000
36.000 6.000 0.000 6.000 3.000
r (radius) delta delta t*{r+2 h
(inches) h*60r fil!g}
12 4320 540
12 4320 810
12 4320 1080
Infiltration
rate (in/hr)
8.000
5.333
4.000
Simple Open Pit Rate to Infiltration Rate Conversion (Porchet Method)
Project Name: Rincon Walnut Ave Project Calculated By: JAB
Project No. 17-11664 Checked By:
Date: 10/17/17
Date:
Test Hole No: INF-2 Test Hole Dia: 24" Depth of Test Hole: 36.5"
Porchet Corrections
Infiltration rate=((delta h*60r)/(delta t*(r+2 h avg))
Test EB Depth Delta T Water Depth Water Depth hl h2 delta h h avg r (radius)
No. (inches) (min) 1 (inches) 2 (inches) (inches) (inches) (inches) (inches) (inches)
1 36.5 20 30.500 36.500 6.000 0.000 6.000 3.000 12
2 36.5 45 30.000 36.500 6.500 0.000 6.500 3.250 12
3 36.5 60 30.000 36.500 6.500 0.000 6.500 3.250 12
4
5
6
7
8
9
delta
h*60r
4320
4680
4680
delta t*(r+2 Infiltration rate
h avg} (in/hr)
360 12.000
832.5 5.622
1110 4.216
APPENDIXC
USDA WEB SOIL SURVEY MAP
3l" 9' 19'"N
N
A
Soil Ma~an Diego County Area, California
Mep ~: 1:516 i' prtud on A pcrtn,it (8.5" X 11") sheet. ~--===-----======-0 5 10 a> 3l o~---25~===::iia,--------,00=========1:a
Map IJujeclion: ~ Merom-Caneraiatlhall!s: WGS84 Edge tics: lJTM ZCne 11N WGS84
Natural Resources
Conservation Service
Web Soll Survey
National Cooperative Soll Survey
10/30/2017
Page 1 of 3
=
Soil Map-San Diego County Area, California
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
D Area of Interest {ADI)
Soils
_J Soil Map Unit Polygons
Soil Map Unit Lines
• Soil Map Unit Points
Special Point Features
~
~
X
.x
~
A
~
.;!,.
'.
+
..;:.
~;
II
Natural Resources
Conservation Service
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Sip
Sodlc Spot
'-> ""' Spoil Area
0 Stony Spot
~ Very Stony Spot
,:tr; •j Wet Spot
,:\ Other .. Special Line Features
Water Features
,,-...,, Streams and Canals
Transportation
+++ Rails
-Interstate Highways
-US Routes
Major Roads
Local Roads
Background
• Aerial Photography
Web Soil Survey
National Cooperative Soil Survey
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placemenl The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soll Survey Area: San Diego County Area, California
Survey Area Data: Version 10, Sep 12, 2016
Soil map units are labeled (as space allows) for map scales
1 :50,000 or larger.
Date(s) aerial images were photographed: Nov 3, 2014-Nov
22,2014
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
10/30/2017
Page 2 of 3
Soil Map-San Diego County Area, California
Map Unit Legend
I
I Map Unit Symbol
MIC
' I I Totals for Area of Interest
Natural Resources
Conservation Service
Map Unit Name Acres In AOI
Marina loamy coarse sand, 2
to 9 percent slopes
-
Web Soil Survey
National Cooperative Soll Survey
Percent of AOI
0.6
0.6 --
100.0%;
100.0% !
10/30/2017
Page 3 of 3
Map Unit Description: Marina loamy coarse sand, 2 to 9 percent slopes-San Diego County
Area, California
San Diego County Area, California
MIC-Marina loamy coarse sand, 2 to 9 percent slopes
USDA Natural Resources
ilia Conservation Service
Map Unit Setting
National map unit symbol: hbdz
Mean annual air temperature: 57 to 61 degrees F
Frost-free period: 330 to 350 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Marina and similar soils: 85 percent
Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of
the mapunit.
Description of Marina
Setting
Landform: Ridges
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Eolian sands derived from mixed sources
Typical profile
H1 -0 to 10 inches: loamy coarse sand
H2 -10 to 57 inches: loamy sand, loamy coarse sand
H2 -10 to 57 inches: sand, coarse sand
H3 -57 to 60 inches:
H3 -57 to 60 inches:
Properties and qualities
Slope: 2 to 9 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Somewhat excessively drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat):
Moderately high to high (0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0
to 2.0 mmhos/cm)
Available water storage in profile: Moderate (about 8.7 inches)
Interpretive groups
Land capability classification (irrigated): 3s
Land capability classification (nonirrigated): 4e
Hydrologic Soil Group: B
Hydric soil rating: No
Web Soll Survey
National Cooperative Soll Survey
10/30/2017
Page 1 of 2
•
Map Unit Description: Marina loamy coarse sand, 2 to 9 percent slopes-San Diego County
Area, California
Minor Components
Carlsbad
Percent of map unit: 5 percent
Hydric soil rating: No
Chesterton
Percent of map unit: 5 percent
Hydric soil rating: No
Corralltos
Percent of map unit: 5 percent
Hydric soil rating: No
Data Source Information
Soil Survey Area: San Diego County Area, California
Survey Area Data: Version 10, Sep 12, 2016
Natural Resources
Conservation Service
Web Soll Survey
National Cooperative Soll Survey
10130/201 7
Page 2 of 2
•
APPENDIXD
USGS DESIGN MAPS SUMMARY REPORT
,. •
1112/2017 Design Maps Summary Report
ElJSGS Design Maps Summary Report
User-Specified Input
Report Title Rincon Walnut Avenue
Thu November 2, 2017 19:59:02 UTC
Building Code Reference Document ASCE 7-10 Standard
(which utilizes USGS hazard data available In 2008)
Site Coordinates 33.1558°N, 117.3477°W
Site Soll Classification Site Class D -"Stiff Soil"
Risk Category I/II/III
USGS-Provided Output
S5 = 1.157 g
5 1 = 0.443 9
SMS = 1.200 g
SMl = 0.690 g
' 1'
:<.
',; ~ •.1,-'i. ,_
r,'. ".c 1.i, ~n• ·
,1•.·'""" ~,ponl. : ·. .
.•• 1.;. ·-...., T j }.1rt1 ir" W\
r?·• ~~
f'
S05 = 0.800 g
S0 1 = 0 .460 g
'i. !-,,'"'!~• -
c.. "'
Stn Marcos
For information on how the SS and S1 values above have been calculated from probabilistic (risk-targeted) and
deterministic ground motions in the direction of maximum horizontal response, please return to the application and
select the "2009 NEHRP" building code reference document.
I t
I >
11
"' -~ ~~ , .l' :, :n
For PG.A,., TL' CRS• and CR1 values, please view the detajled report.
Although this information is a product of the U.S. Geological Survey, we provide no warranty, expressed or implied, as to the
accuracy of the data contained therein. This tool 1s not a substitute for technical subject-matter knowledge.
https://earthquake.usgs.gov/cn 1/deslgnmaps/us/summary.php?template=mlnlmal&latltude=33.1558&1ongltude=-117.3477 &sileclass=3&riskcategory=O... 1 /1
•
# 11/2/2017 Design Maps Detailed Report
ZIJSGS Design Maps Detailed Report
ASCE 7-10 Standard (33.1558°N, 117.3477°W)
Site Class D -"Stiff Soil", Risk Category I/II/III
Section 11.4.1 -Mapped Acceleration Parameters
Note: Ground motion values provided below are for the direction of maximum horizontal
spectral response acceleration. They have been converted from corresponding geometric
mean ground motions computed by the USGS by applying factors of 1.1 (to obtain S5) and
1.3 (to obtain S1). Maps In the 2010 ASCE-7 Standard are provided for Site Class B.
Adjustments for other Site Classes are made, as needed, in Section 11.4.3.
From Figure 22-1 c11 Ss = 1.157 g
From Figure 22-2 c21 S 1 = 0.443 g
Section 11.4.2 -Site Class
The authority having jurisdiction (not the USGS), site-specific geotechnical data, and/or
the default has classified the site as Site Class D, based on the site soil properties in
accordance with Chapter 20.
Table 20.3-1 Site Classification
Site Class
A. Hard Rock
B. Rock
C. Very dense soil and soft rock
D. Stiff Soil
E. Soft clay soil
F. Soils requiring site response
analysis in accordance with Section
21.1
-Nor Nch -Vs Su
>5,000 ft/s N/A N/A
2,500 to 5,000 ft/s N/A N/A
1,200 to 2,500 ft/s >SO >2,000 psf
600 to 1,200 ft/s 15 to 50 1,000 to 2,000 psf
<600 ft/s <15 <1,000 psf
Any profile with more than 10 ft of soil having the
cha ra cte ristics:
• Plasticity index PI > 20,
• Moisture content w ~ 40%, and
• Undrained shear strength su < 500 psf
See Section 20.3.1
For SI: lft/s = 0.3048 m/s 11b/ft2 = 0 .0479 kN/m2
https://earthquake.usgs.gov/cn1 /designmaps/us/report. php?template=minimal&latitude=33.1558&Iongitude=-117 .34 77 &siteclass=3&riskcategory=0&e... 1 /6
•
"11/2/2017 Design Maps Detailed Report
Section 11.4.3 -Site Coefficients and Risk-Targeted Maximum Considered Earthquake C.M.C.J;:,R)
Spectral Response Acceleration Parameters
Table 11.4-1: Site Coefficient F.
Site Class Mapped MCE R Spectral Response Acceleration Parameter at Short Period
S5 :5 0.25 S5 = 0.50 S5 = 0.75 S5 = 1.00 S5 2! 1.25
A 0.8 0.8 0.8 0.8 0.8
B 1.0 1.0 1.0 1.0 1.0
C 1.2 1.2 1.1 1.0 1.0
D 1.6 1.4 1.2 1.1 1.0
E 2.5 1.7 1.2 0.9 0.9
F See Section 11.4.7 of ASCE 7
Note: Use straight-line interpolation for intermediate values of S5
For Site Class = D and S5 = 1.157 g, F. = 1 .037
Table 11.4-2: Site Coefficient Fv
Site Class Mapped MCE R Spectral Response Acceleration Parameter at 1-s Period
S1 :5 0.10 s, = 0.20 S1 = 0.30 S1 = 0.40 S1 2! 0.50
A 0.8 0.8 0.8 0.8 0.8
B 1.0 1.0 1.0 1.0 1.0
C 1.7 1.6 1.5 1.4 1.3
D 2.4 2.0 1.8 1.6 1.5
E 3.5 3.2 2.8 2.4 2.4
F See Section 11.4. 7 of ASCE 7
Note: Use straight-line interpolation for intermediate values of S1
For Site Class = D and S1 = 0.443 g, F, = 1.557
hllps://earthqua ke .usgs. gov/en 1 /designmaps/us/report.php ?template=m ini mal&latitudeaa33. 1558&Iongitude=-117. 34 77 &slteclass=3&riskcategory=0&e. . . 2/6
.. * 11/2/2017
Equation (11.4-1):
Equation (11.4-2):
Design Maps Detailed Report
SMs = F.S5 = 1.037 x 1.157 = 1.200 g
SMl = FvSl = 1.557 X 0.443 = 0.690 g
Section 11.4.4 -Design Spectral Acceleration Parameters
Equation (11.4-3): Sos=½ SMs = ½ X 1.200 = 0.800 g
Equation (11.4-4): S01 = ½ SMl = ½ X 0.690 = 0.460 g
Section 11.4.5 -Design Response Spectrum
From Figure 22-12 c31 TL = 8 seconds
Figure 11.4-1: Design Response Spectrum
:.s:.
~.<5: ' . --.-·-··--····,·-··
. ,,
T < T~: s. = S116 ( o.4 + o.s T tT0 )
T0 =i Ts T6 : s. = S05
Ts < TS TL : S0 = S01 / T
T> TL: S0 =S01TLIT1
' '
https:l/earlhquake.usgs.gov/cn1 /designmaps/us/report.php?template=mlnlmal&latitude=33 .1558&Iongitude=-117 .34 77&siteclass=3&riskcategory=O&e... 3/6
Design Maps Detailed Report
Section 11.4.6 -Risk-Targeted Maximum Considered Earthquake (MCER) Response Spectrum
The MCER Response Spectrum is determined by multiplying the design response spectrum above by
s,r, • 1.200
1.5.
I
I S., -0.690 -1-------------' ----------
To• .115 ,, -0.575
I
I
I
1.0::.0
P~tod. T (,ec)
https://earthquake .usgs.gov/cn1 /designmaps/us/report.php?template=minimal&latitude=33. 1558&1ongitude=-117 .34 77 &siteclass=3&riskcategory=0&e... 4/6
4
.,11/2/2017 Design Maps Detailed Report
Section 11.8.3 -Additional Geotechnical Investigation Report Requirements for Seismic Design
Categories D through F
From Figure 22-7 c41 PGA = 0.460
Equation (11.8-1): PGAM = FPGAPGA = 1.040 x 0.460 = 0.479 g
Table 11.8-1: Site Coefficient FPGA
Site Mapped MCE Geometric Mean Peak Ground Acceleration, PGA
Class
PGA:; PGA = PGA = PGA = PGA ~
0.10 0.20 0.30 0.40 0.50
A 0.8 0.8 0.8 0.8 0.8
B 1.0 1.0 1.0 1.0 1.0
C 1.2 1.2 1.1 1.0 1.0
D 1.6 1.4 1.2 1.1 1.0
E 2.5 1. 7 1.2 0.9 0.9
F See Section 11.4. 7 of ASCE 7
Note: Use straight-line interpolation for intermediate values of PGA
For Site Class = D and PGA = 0.460 g, Fp0,. = 1.040
Section 21.2.1.1 -Method 1 (from Chapter 21 -Site-Specific Ground Motion Procedures for
Seismic Design)
From Figure 22-17 csi CRS = 0.937
From Figure 22-18 C6 l C Rl = 0.990
https://earthquake .usgs.gov/cn 1 /deslgnmaps/uslreport.php?template=minimal&lalitude=33.1558&Iongitude=-117 .3477 &siteclass=3&riskcategory=0&e... 516
,.
~/2/2017 L Design Maps Detailed Report
Section 11.6 -Seismic Design Category
Table 11.6· 1 Seismic Design Category Based on Short Period Response Acceleration Parameter
RISK CATEGORY
VALUE OF S05 I or II III IV
S05 < 0.167g A A A
0.167g S S0s < 0.33g B B C
0.33g S S0 s < O.SOg C C D
O.SOg S S05 D D D
For Risk Category = I and S05 = 0.800 g, Seismic Design Category = D
Table 11.6-2 Seismic Design Category Based on l·S Period Response Acceleration Parameter
RISK CATEGORY
VALUE OF SO1 I or II III IV
SO1 < 0.067g A A A
0.067g :S SO1 < 0,133g B B C
0.133g S S01 < 0.20g C C D
0.20g :S S01 D D D
For Risk Category = I and 501 = 0.460 g, Seismic Design Category= D
Note: When S1 Is greater than or equal to 0.75g, the Seismic Design Category is E for
buildings in Risk Categories I, II, and III, and F for those in Risk Category IV, irrespective
of the above.
Seismic Design Category = "the more severe design category in accordance with
Table 11.6-1 or 11.6-2" = D
Note: See Section 11.6 for alternative approaches to calculating Seismic Design Category.
References
1. Figure 22-1: https://earthquake.usgs.gov/hazards/designmaps/downloads/pdfs/2010_ASCE-7 _Figure_22· 1. pdf
2. Figure 22-2: https://earthqua ke. usgs.gov/hazards/designmaps/downloads/pdfs/2010_ASCE· 7 _Figure_22-2. pdf
3. Figure 22-12: https ://earthquake.usgs.gov/hazards/designmaps/downloads/pdfs/20 lO_ASCE-7 _Figure_22-12. pdf
4. Figure 22-7: https://earthquake. usgs.gov/hazards/designmaps/downloads/pdfs/2010_ASCE-7 _Figure_22-7 .pdf
5. Figure 22-17: https://earthquake.usgs.gov/hazards/designmaps/downloads/pdfs/2010_ASCE-7 _Figure_22-17 .pdf
6. Figure 22-18: https ://earthquake.usgs.gov/hazards/designmaps/downloads/pdfs/2010_ASCE-7 _Figure_22-18.pdf
https://earthquake. usgs.gov/cn 1 /designmaps/us/report.php?template=minimal&latitude=33.1558&Iongitude::-117 .34 77 &slteclass=3&riskcategory=O&e... 6/6