HomeMy WebLinkAbout20191218_Geotechnical InvestigationCOAST GEOTECHNICAL, INC.
Geotechnical Engineering Investigation
of
Proposed New Residence
at
; 5009 Seashore Drive
Newport Beach, California
BY:
COAST GEOTECHNICAL, INC.
W. O. 584919-01, December 2, 2019
FOR:
Mr. Tom Nicholson
C/o Brian Flood
412 De Sola Terrace
Corona Del Mar, CA 92625
PA2019-264
COAST GEOTECHNICAL, INC.
1200 W. Commonwealth Avenue, Fullerton, CA 92833 • Ph: /714) 870-1211 • Fax: /714) 870-1222 • E-mail: coastgeotec@sbcglobal.net
December 2, 2019
Mr. Tom Nicholson
Nicholson Companies
Clo Brian Flood
412 De Sola Terrace
Corona Del Mar, CA 92625
Gentlemen:
Subject:
w.o. 584919-01
Geotechnical Engineering Investigation of
Proposed New Residence at 5009 Seashore
Drive, Newport Beach, California
Pursuant to your request, a geotechnical engineering investigation has been performed at the subject
site. The purposes of the investigation were to determine the general engineering characteristics of
the near surface soils on and underlying the site and to provide recommendations for the design of
foundations and underground improvements.
The conclusions and recommendations contained in this report are based upon the understanding of
the proposed development and the analyses of the data obtained from our field and laboratory
testing programs.
This report completes our scope of geotechnical engineering services authorized by you in the
September 20, 2019 proposal.
SITE DEVELOPMENT
It is our understanding that the existing residence will be demolished and that the site is to be
redeveloped with a three story residential structure over slab on grade. Structural loads are
anticipated to be light. Significant grade changes are not anticipated.
PURPOSE AND SCOPE OF SERVICES
The scope of the study was to obtain subsurface information within the project site area and to
provide recommendations pertaining to the proposed development and included the following:
1. A cursory reconnaissance of the site and surrounding areas.
2. Excavation of two exploratory borings to detennine the near subsurface soil conditions and
groundwater conditions.
3. Collection of representative bulk and/or undisturbed soil samples for laboratory analysis.
4. Laboratory analyses of soil samples including detennination of in-situ and maximum density, in-
situ and optimum moisture content, shear strength characteristics, expansion potential, and sulfate
content.
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5. Preparation of this report presenting results of our investigation and recommendations of the
proposed development.
SITE CONDITIONS
The project site is located at 5009 Seashore Drive, in the City of Newport Beach, California, and is
shown on the attached Site Vicinity Map, Plate 1.
The parcel is rectangular in shape, near level, and bordered by Seashore Drive to the north, the
beach to the south, and residential properties to the east and west.
The lot is currently developed with a two story residential structure and hardscape. Site
configuration is further shown on the Site Plan, Plate 2.
EXPLORATORY PROGRAM
The fidd investigation was performed on November 1 & 5, 2019, consisting of the excavation of a
boring by a limited access drilling equipment (for Boring No. 1) and a boring by hand auger
equipment (for Boring No. 2) at the locations shown on the attached Site Plan, Plate 2. As
excavations progressed, a representative from this office visually classified the earth materials
encountered, and secured representative samples for laboratory testing.
Geotechnical characteristics of subsurface conditions were assessed by either driving a split spoon
ring sampler or an SPT sampler into the earth material.
Undisturbed samples for detailed testing in our laboratory were obtained from Boring No. 2 by
pushing or driving a sampling spoon into the earth material. A solid-barrel type spoon was used
having an inside diameter of 2.5 inches with a tapered cutting tip at the lower end and a ball valve
at the upper end.
The barrel is lined with thin brass rings, each one inch in length. The spoon penetrated into the earth
materials below the depth of borings approximately six inches. The central portion of this sample
was retained for testing. All samples in their natural field condition were sealed in airtight
containers and transported to the laboratory.
Standard Penetration Test (SPT) was performed for Boring No. 1, based on ASTM D1586. The
number of blows required for driving the sampler through three six-inch intervals is recorded. The
sum of the number of blows required for driving the last two six-inch intervals is referred to as the
standard penetration number "N".
The sampler from Boring No. 1 was driven into the soil at the bottom of the borehole by means of
hammer blows. The hammer blows are given at the top of the drilling rod. The blows are by a
hammer weighing 140 pounds dropped a distance of 30 inches. Drive sampling was obtained at two
feet intervals for the upper level foundations in accordance with City guidelines. Considering that
the upper three feet of the pad area will be recompacted, SPT sampling commenced at three feet
below grade.
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For liquefaction analysis, CE of 1.0 (for safety hammer), CB of 1.05 (for seven inch borehole
diameter), and Cs of 1.2 (for sampler without liners) are used to calculate corrected N values.
EARTH MATERIALS
Earth materials encountered within the exploratory borings were visually logged by a representative
of COAST GEOTECHNICAL, INC. The earth materials encountered were classified as artificial
fill underlain by native soils to the maximum depth explored.
Artificial fills encountered consisted of silty to clean, fine to medium grained sand, gray brown to
brown in color, dry to damp, and generally surficially loose to medium dense with depth. The fills
were encountered to a depth of about one and a half to two feet below existing grade.
Native soils encountered consisted of clean, fine to coarse grained sand, tan to tan brown and gray
tan in color, damp to wet, and generally medium dense, to the maximum depth explored of 12.5
feet.
Logs of the exploratory borings are presented on the appended Plates B and C.
GROUNDWATER
Groundwater was encountered at seven feet below existing ground surface during the field
investigation. This groundwater level is subject to fluctuation due to tidal changes. Plate 1.2 in
Appendix B shows the subject site area to have a historic high groundwater level of less than ten
feet below ground surface. In our liquefaction and seismic settlement analyses, a groundwater
elevation of five feet below ground surface is used for more conservative calculations.
SEISMICITY
Southern California is located in an active seismic region. Moderate to strong earthquakes can
occur on numerous faults. The United States Geological Survey, California Division of Mines and
Geology, private consultants, and universities have been studying earthquakes in
Southern California for several decades. Early studies were directed toward earthquake prediction
estimation of the effects of strong ground shaking. Studies indicate that earthquake prediction is
not practical and not sufficiently accurate to benefit the general public. Governmental agencies are
shifting their focus to earthquake resistant structures as opposed to prediction. The purpose of the
code seismic design parameters is to prevent collapse during strong ground shaking.
Cosmetic damage should be expected.
Within the ·past 48 years, Southern California and vicinity have experienced an increase in seismic
activity beginning with the San Francisco earthquake in 1971. In 1987, a moderate earthquake
struck the Whittier area and was located on a previously unknown fault. Ground shaking from this
event caused substantial damage to the City of Whittier, and surrounding cities. The
January 17, 1994, Northridge earthquake was initiated along a previously unrecognized fault below
the San Fernando Valley. The energy released by the earthquake propagated to the southeast,
northwest, and northeast in the form of shear and compression waves, which caused the strong
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ground shaking in portions of the San Fernando Valley, Santa Monica Mountains, Simi Valley,
City of Santa Clarita, and City of Santa Monica.
Southern California faults are classified as: active, potentially active, or inactive. Faults from past
geologic periods of mountain building, but do not display any evidence of recent offset, are
considered "inactive" or "potentially active". Faults that have historically produced earthquakes or
show evidence of movement within the past 11,000 years are known as "active faults". There are no
known active faults within the subject property, with the nearest being the Newport Inglewood
Fault Zone and the San Joaquin Blind Thrust Fault.
• Newport-Inglewood Fault Zone: The Newport-Inglewood Fault Zone is a broad zone of left-
stepping en echelon faults and folds striking southeastward from near Santa Monica across the
Los Angeles basin to Newport Beach. Altogether these various faults constitute a system more
than 150 miles long that extends into Baja California, Mexico. Faults having similar trends and
projections occur offshore from San Clemente and San Diego (the Rose Canyon and La Nacion
Faults). A near-shore portion of the Newport-Inglewood Fault Zone was the source of the
destructive 1933 Long Beach earthquake. The reported recurrence interval for a large event alorig
this fault zone is 1,200 to 1,300 years with an expected slip of one meter.
• San Joaquin Hills Blind Thrust Fault: The seismic hazards in Southern California have been
further complicated with the recent realization that major earthquakes can occur on large thrust
faults that are concealed at depths between 5 to 20 km, referred to as "blind thrusts." The uplift
of the San Joaquin Hills is produced by a southwest dipping blind thrust fault that extends at
least 14 km from northwestern Huntington Mesa to Dana Point and comes to within 2 km of the
ground surface. Work by Grant et al. (1997 and 1999) suggest that uplift of the San Joaquin Hills
began in the Late Quaternary and continues during the Holocene. Uplift rates have been
estimated between 0.25 and 0.5 mm/yr. If the entire length of the fault ruptured, the earthquake
has been estimated to generate an Mw 6.8 event.
We are of the opinion that the more active Newport Inglewood fault is the causative fault for the
subject site. The site is located approximately 1 kilometer northeast of the Newport Inglewood
fault.
SEISMIC HAZARDS
The potential hazards to be evaluated with regard to seismic conditions include fault rupture,
landslides triggered by ground shaking, soil liquefaction, earthquake-induced vertical and lateral
displacements, earthquake-induced flooding due to the failure of water containment structures,
seiches, and tsunamis.
Fault Rupture
The project is not located within a currently designated Alquist-Priolo Earthquake Zone (Bryant
and Hart, 2007). No known active faults are mapped on the site. Based on this consideration, the
potential for surface fault rupture at the site is considered to be remote.
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Ground Shaking
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The site is located in a seismically active area that has historically been affected by moderate to
occasionally high levels of ground motion, and the site lies in relatively close proximity to
several active faults; therefore, during the life of the proposed development, the property will
probably experience moderate to occasionally high ground shaking from these fault zones, as
well as some background shaking from other seismically active areas of the Southern California
region. Designs of residential structures are typically to maintain structural integrity not to
prevent damage. Earthquake insurance is available where the damage risk is not acceptable to the
client.
Seismic Induced Landslide
Earthquake-induced landslide zones were delineated by the State of California using criteria
adopted by the California State Mining and Geology Board. Under those criteria, earthquake-
induced landslide zones are areas meeting one or more of the following:
1. Areas known to have experienced earthquake-induced slope failure during historic earthquakes.
2. Areas identified as having past landslide movement, including both landslide deposits and source
areas.
3. Areas where CDMG's analyses of geologic and geotechnical data indicate that the geologic
materials are susceptible to earthquake-induced slope failure.
Based on the Seismic Hazard Zone Map published by the State of California, Newport Beach
Quadrangle, appended as Plate 3, the site is not mapped as being in an area subject to potential
seismic induced landslides.
Seismic Induced Liquefaction
Liquefaction is a seismic phenomenon in which loose, saturated, non-cohesive granular soils
exhibit severe reduction in strength and stability when subjected to high-intensity ground
shaking. The mechanism by which liquefaction occurs is the progressive increase in excess pore
pressure generated by the shaking associated with the seismic event and the tendency for loose
non-cohesive soils to consolidate. As the excess pore fluid pressure approaches the in-situ
overburden pressure, the soils exhibit behavior similar to a dense fluid with a corresponding
significant decrease in shear strength and increase in compressibility. Liquefaction occurs when
three general conditions exist: 1) shallow groundwater; 2) low density, non-cohesive sandy soils;
and 3) high-intensity ground motion.
Seismic Hazard Zone Maps published by the State of California have been prepared to indicate
areas that have a potential for seismic induced liquefaction hazards. The Seismic Hazard Zone
Map for the Newport Beach Quadrangle, appended as Plate 3, shows the site to be mapped as
being subject to potential liquefaction hazards.
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The City of Newport Beach has a policy concerning these areas. The City has assigned certain
parameters to existing soil conditions. From ten to thirty feet below ground surface they have
assigned the zone to be liquefiable with a seismic settlement of three inches. From thirty to fifty
feet below ground surface they have assigned liquefaction and seismic settlement not to be of
concern. The client has the option of accepting these conditions and assessing the zone of earth
materials from the ground surface to ten feet below the proposed footing bottom for liquefaction
and seismic settlement, or ignoring the City conditions and drilling deep exploration for similar
assessment.
For this project shallow exploration was chosen. A liquefaction assessment for the upper earth
materials follows.
Liquefaction evaluation for soil zone to ten feet below foundation bottom was based on blow
counts from Boring No. 1, a M = 7.2 seismic event from the Newport-Inglewood fault, a
maximum ground acceleration of 0.692g PGAM and a groundwater level at five feet.
Liquefaction analysis, based on these values and field obtained data, is presented in Appendix B.
The results indicate that there is liquefaction potential for the subject site.
Lateral Spreading
The occurrence ofliquefaction may cause lateral spreading. Lateral spreading is a phenomenon in
which lateral displacement can occur on the ground surface due to movement of non-liquefied
soils along zones of liquefied soils. For lateral spreading to occur, the liquefiable zone must be
continuous, unconstrained laterally, and free to move along sloping ground toward an unconfined
area.
Due to the relatively level lot and distance to a free face, the potential of lateral spreading is not
considered to be significant.
Earthquake-induced Settlements
Earthquake-induced settlements result from densification of non-cohesive granular soils which
occur as a result of reduction in volume during or after an earthquake event. The magnitude of
settlement that results from the occurrence of liquefaction is typically greater than the settlement
that results solely from densification during strong ground shaking in the absence ofliquefaction.
It is understanding that the current City policy, has assigned a seismic settlement potential of
three inches for soils depths of ten to thirty feet and no additional analysis of seismic settlement
for this level should be required.
The seismically induced settlement for the at-grade structure was evaluated based on the
"Evaluation of Settlement in Sands due to Earthquake Shaking" by Kahji Tokimatsu and
H. Bolton Seed, dated August 1987. The analysis was limited to ten feet below the footing
bottom. The result, based on the SPT N-values in Boring No. 1, groundwater table at five feet
below grade and shown in Appendix C, indicates that the estimated settlement (including dry and
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saturated sands) is 0.44 inch. According to City policy, the City's shallow mitigation method may
be used since the seismic settlement is less than one inch to a depth of ten feet below proposed
foundations.
Earthquake-Induced Flooding
The failure of dams or other water-retaining structures as a result of earthquakes and strong
ground shaking could result in the inundation of adjacent areas. Due to the lack of a major dam
or water-retaining structure located near the site, the potential of earthquake-induced flooding
affecting the site is considered not to be present.
Seiches
Seiches are large waves generated in enclosed bodies of water in response to ground shaking.
Based on the lack of nearby enclosed bodies of water the risk from a seiche event is not present.
Tsunamis
Tsunamis are waves generated in large bodies of water as a result of change of seafloor topography
caused by tectonic displacement or landslide.
Based on the City of Newport Beach "Potential Tsunami Runup Inundation Caused by a Submarine
Landslide" map, the subject site is situated in the zone for potential tsunami run-up as shown on
Plate 5, and is referenced on this plate to be areas below elevation 32 feet. For more information
about tsunami run-up hazards and evacuation routes you are referred to the City website.
GEOTECHNICAL DISCUSSION
The site is within an area subject to liquefaction and liquefaction induced settlements under certain
seismic events. Under current CBC codes, City policy, and industry standards residential structures
subject to seismic hazards are designed to protect life and safety. Under this design objective the
requirements of protecting life and safety could be met but the structure could be damaged. The
damage to the structure could range from minimal to being non-functional. The reduction of risk,
for the occurrence of structural damage from a seismic event, is generally associated with the
structure's foundation system.
Typically the use of a conventional foundation system or a mat foundation system has been utilized
in the area.
Based on analysis presented within this report and City guidelines concerning liquefaction study
mitigation measures the proposed structure can be developed utilizing the City's "strengthened slab
on grade foundation system" for support. This type of foundation system, also referred to as a
conventional foundation system, is a minimum design. As the minimum design, this foundation
system has the highest risk for occurrence of structural damage to the residence.
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The minimum geotechnical requirements for a conventional foundation system are as follows:
(1) the structure shall be placed on a mat of compacted fill soil, (2) bottom of all footings shall be
24 inches below grade, (3) foundations shall be continuous or tied together with grade beams, (4)
foundations shall be reinforced with a minimum of four #5 bars, two top and two bottom, (5)
concrete slabs shall be a minimum of five inch actual thickness with #4 bars at 12 inches on
center each way, and (6) footings shall be dowelled into slabs with #4 bars at 24 inches on center.
Additional reinforcement may be required if the structural engineer's design is more stringent.
An alternate foundation system typically utilized is a structural mat foundation, which is more rigid
than a conventional foundation system, and should be more effective in reducing the risk of
structural damage to a structure during a seismic event. Where a mat slab foundation is planned, the
slab should be at least twelve inches thick with a perimeter edge a minimum of 24 inches below the
lowest adjacent grade. Reinforcement shall be determined by the structural engineer.
If the risk associated with either of these foundation systems is not acceptable to the client, the
client has the option of utilizing more stringent designs that could decrease the risk of damage to
the structure to a level they perceive as acceptable. Some of these designs could consist of soil
modifications, grout densification, stone columns, piles placed below liquefiable soils, and other
methods. Additional geotechnical exploration and or analysis would be required to provide
geotechnical design recommendation for these mitigation measures, and would be at the request of
the client under separate contract.
Grading will be required for support of new fotmdations as stated within this report.
Development of the site as proposed is considered feasible from a soils engineering standpoint,
provided that the recommendations stated herein are incorporated in the design and are
implemented in the field. The proposed grading and or construction will not have an adverse
effect on adjacent property or vice versa, provided site work is performed in accordance with the
guidelines of project geotechnical reports, approved plans, applicable codes, industry standards,
City inspections, and required geotechnical observation and testing.
The following recommendations are subject to change based on review of final foundation and
grading plans.
PROPOSED GRADING
Grading plans were not available at the time this report was prepared. It is anticipated that grading
will consist mainly of over-excavation and recompaction for uniform support of the foundations
and slabs.
GENERAL GRADING NOTES
All existing structures shall be demolished and all vegetation and debris shall be stripped and
hauled from the site. The entire grading operation shall be done in accordance with the attached
"Specifications for Grading".
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Any import fill materials to the site shall not have an expansion index greater than 20, and shall be
tested and approved by our laboratory. Samples must be submitted 48 hours prior to import.
Grading and/or foundation recommendations are subject to modification upon review of final plans
by the Geotechnical Engineer. Please submit plans to COAST GEOTECHNICAL, Inc. when
available.
GRADING RECOMMENDATIONS
Removal and recompaction of existing earth materials will be required to provide adequate
support for foundations and site improvements. Earthwork for foundation support shall include
the entire building pad and shall extend a minimum of three feet outside exterior footing lines.
Based on in place densities and consolidation tests, soils found at a depth of three feet below
existing grade and deeper have adequate geotechnical properties to provide adequate support of
proposed fills and the structure; as such, removals to a depth of three feet below existing grade or to
one foot below proposed footing bottoms, whichever is greater, are anticipated; however, field
observations made at the time of grading shall determine final removal limits.
To provide adequate support along property lines excavations shall be sloped at a 1:1 (H:V)
gradient from property line down to the excavation bottom. As fill soils are placed the grading
contractor shall bench into the 1: 1 construction cut to final grade. Temporary excavations along
property lines are shown on Plate 4. Where these temporary sloped excavations cannot be made
shoring will be necessary.
During earthwork operations, a representative of COAST GEOTECHNICAL, INC. shall be present
to verify compliance with these recommendations. The grading contractor is advised that at the
time of our investigation earth materials were very dry in the upper three feet. Mitigation of dry
conditions will be required to achieve compaction requirements. It is recommended that a fire'
hose hooked up to a fire hydrant be used to provide the moisture conditioning necessary to
achieve adequate compaction.
Subsequent to approval of the excavation bottom, the area shall be scarified six inches, moisture
conditioned as needed, and compacted to a minimum of 90% relative compaction.
Fill soils shall be placed in six to eight inch loose lifts, moisture conditioned as needed, and
compacted to a minimum of 90% relative compaction. This process shall be utilized to finish
grade. Due to the caving nature of the onsite sands, it is highly recommended that the upper two
feet of fill be mixed with Portland cement to mitigate the potential for caving of the foundation
excavations.
Grading for hardscape areas shall consist of removal and recompaction of loose surficial soils.
Removal depths are estimated at one to two feet. Earthwork shall be performed in accordance
with previously specified methods.
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FOUNDATIONS -RESIDENCE
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The proposed structures shall be supported by a mat foundation or a conventional foundation.
A conventional foundation system utilizing spread footings and/or isolated pad footings placed a
minimum depth of 24 inches below lowest adjacent grade utilizing an allowable bearing value of
1,800 pounds per square foot. This value is for dead plus live load and may be increased 1/3 for
total including seismic and wind loads where allowed by code. Calculations are provided on
Plate G. The structural engineer's reinforcing requirements should be followed if more stringent.
Where isolated pads are utilized, they shall be tied in two directions into adjacent foundations
with grade beams.
Conventional footing excavations shall be observed by a representative of COAST
GEOTECHNICAL, INC., prior to placement of steel or concrete to verify competent soil
conditions. If unacceptable soil conditions are exposed mitigation will be recommended.
Geotechnical recommendations for foundation reinforcement are given under the liquefaction
section of this report.
If a mat slab design is utilized, the structural engineer should design the thickness and
reinforcement requirements for the mat foundation for the building based on the anticipated
loading conditions. The mat foundation slab should be at least twelve inches thick, with
perimeter footings a minimum of 24 inches below the lowest adjacent grade. A modulus of
subgrade reaction of 100 pci may be used in the design of the mat foundation. Reinforcement
shall be determined by the structural engineer. Calculations for the subgrade reaction are
provided on Plate I.
Alternate foundations and/or additional ground modification techniques, for support of the
structure, can be addressed upon request of the project manager. All foundation plans are subject
to review and approval of the soils engineer.
All mat foundation bottoms shall be observed and approved by COAST GEOTECHNICAL, Inc.
prior to placement of the capillary break.
FOUNDATIONS-SECONDARY STRUCTURES
Property line walls, planter walls, and other incidental foundations may utilize conventional
foundation design.
Continuous spread footings or isolated pads placed a minimum depth of 24 inches below lowest
adjacent grade or 12 inches into native, whichever is greater, may utilize an allowable bearing
value of 1,500 pounds per square foot. This value is for dead plus live load and may be increased
1/3 for total including seismic and wind loads where allowed by code.
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Where isolated pads are utilized, they shall be tied in two directions into adjacent foundations
with grade beams.
Footing excavations shall be observed by a representative of COAST GEOTECHNICAL, Inc.,
prior to placement of steel or concrete to verify competent soil conditions. If unacceptable soil
conditions are exposed mitigation will be recommended.
Foundations shall be reinforced with a minimum of four #5 bars, two top and two bottom, The
structural engineer's recommendations for reinforcement shall be utilized where more severe.
LATERAL DESIGN
Lateral restraint at the base of footings and on slabs may be assumed to be the product of the dead
load and a coefficient of friction of 0.35. Passive pressure on the face of footings may also be used
to resist lateral forces. A passive pressure of zero at the surface of finished grade, increasing at the
rate of 300 pounds per square foot of depth to a maximum value of 3,000 pounds per square foot,
may be used for compacted fill at this site. Calculations are provided on Plate H. If passive pressure
and friction are combined when evaluating the lateral resistance, then the value of the passive
pressure should be limited to 2/3 of the values given above.
FLOOR SLABS
Slab on grades shall be designed in accordance with current CBC codes.
Site soils are non plastic.
Minimum geotechnical recommendations for slab design are five inches actual thickness with #4
bars at 12 inches on center each way. Slabs shall be tied into perimeter foundations with #4 bars at
24 inch centers. Structural design may require additional reinforcement and slab thickness.
Slab on grade areas shall be supported on engineered fill compacted to a minimum of 90%
relative compaction and exhibiting proper moisture content. Subgrade soil should be kept moist
prior to casting the slab. However, if the soils at grade become disturbed during construction,
they should be brought to approximately optimum moisture content and rolled to a firm,
unyielding condition prior to placing concrete. COAST GEOTECHNICAL, Inc. to verify
adequacy of sub grade spoils prior to placement of gravel or visqueen.
Subgrade soils shall exhibit a minimum of 90% relative compaction to the depth determined by
the geotechnical engineer. The soil should be kept moist prior to casting the slab; however, if the
soils at grade become disturbed during construction, they should be brought to approximately
optimum moisture content and rolled to a firm, unyielding condition prior to placing concrete.
Section 4.505.2.1 of the California Green Code requires the use of a capillary break between the
slab subgrade and vapor barrier. The capillary break material shall comply with the requirements
of the local jurisdiction and shall be a minimum of four inches in thickness. Geotechnically
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coarse clean sand is acceptable; however, some localities require the use of four inches of gravel
(1/2-inch or larger clean aggregate). If gravels are used, a heavy filter fabric (Mirafi 140N) shall
be placed over the gravels prior to placement of the recommended vapor barrier to minimize
puncturing of the vapor barrier. Additionally, a vibratory plate should be used over the gravels
prior to placement of the recommended filter fabric to smooth out any sharp protuberances and
consolidate the gravels.
Slab areas should be underlain by a vapor retarder consisting of an engineered plastic film (as
described by ASTM:E-1745). In areas where a moisture sensitive floor covering will be used
and/or where moisture infiltration is not desirable, a vapor barrier with a permeance of less than
0.Olperrns (consistent with ACI 302.2R-06) such as 15 mil. Stego Wrap Vapor Barrier, or
equivalent, should be considered, and a qualified water proofing specialist should be consulted.
The vapor barrier should be underlain by the above described capillary break materials and filter
cloth. The capillary break materials should be compacted to a uniform condition prior to
placement of the recommended filter cloth and vapor barrier. The vapor barrier should be
properly lapped and sealed.
SEISMIC DESIGN
Based on the current CBC the following seismic design parameters are provided. These seismic
design values were determined utilizin~ latitude 33.62223 and longitude -117.94286 and
calculations from the SEAOC/OSHPD seismic design calculator. A conservative site class D was
assigned to the site earth materials.
• Site Class = D
• Mapped 0.2 Second Spectral Response Acceleration, Ss = 1.693g
• Mapped One Second Spectral Response Acceleration S1 = 0.626g
• Site Coefficient from Table 1613A.3.3(1), Fa= 1.0
• Site Coefficient from Table 16 l 3A.3 .3(2), Fv = 1.5
• Maximum Design Spectral Response Acceleration for short period, SMs = 1.693 g
• Maximum Design Spectral Response Acceleration for one-second period, SMt = 0.94g
• 5% Design Spectral Response Acceleration for short period, Sns = 1.129g
• 5% Design Spectral Response Acceleration for one-second period, Sm = 0.626g
SETTLEMENT
The maximum total post-construction static settlement is anticipated to be on the order of 1/2 inch.
Differential settlements are expected to be less than 1/2 inch, measured between adjacent structural
elements over a distance of 40 feet. Seismic induced settlements are addressed under previous
sections.
SUBSIDENCE & SHRINKAGE
Subsidence over the site is anticipated to be negligible. Shrinkage of reworked materials should be
in the range of 5 to 10 percent.
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Geotechnical Engineering Investigation
EXPANSIVE SOILS
13 w. 0. 584919-01
December 2, 2019
Results of expansion tests indicate that the near surface soils have a very low expansion potential.
UTILITY LINE BACKFILLS
All utility line backfills, both interior and exterior, shall be compacted to a 1l11Il1111um of
90% relative compaction and shall require testing at a maximum of two-foot vertical intervals.
Utility lines shall be placed at appropriate depths. Shallow pipes can be damaged by the forces
imposed by compacting backfill soils. If shallow pipes are not capable of withstanding the forces of
backfill compaction, slurry backfill will be recommended.
HARDSCAPE AND SLABS
Hardscape and slab subgrade areas shall exhibit a minimum of 90% relative compaction to a depth
of at least one foot. Deeper removal and recompaction may be required if unacceptable conditions
are encountered. These areas require testing prior to placing steel or concrete. Hardscape shall be at
least four inches thick and reinforced with #3 bars on 18 inch centers both ways.
CHEMICAL ANALYSIS
An on-site soil sample showed a soluble sulfate content of 58 ppm, which is a negligible sulfate
exposure. Concrete with Type II 2,500 psi may be utilized; however, the saltwater environ may
cause damage to exposed concrete and a designed concrete should be considered.
DRAINAGE
Positive drainage should be planned for the site. Drainage should be directed away from structures
via non-erodible conduits to suitable disposal areas. The structure should utilize roof gutters and
down spouts tied directly to yard drainage.
Pipes used for storm/site water drainage should be stout enough to withstand the force of
compaction of the soils above. This force can be considerable, causing some weaker pipes to
collapse. Drainage pipes shall have a smooth interior. Pipes with a corrugated interior can cause the
buildup of deleterious matter, which can impede or block the flow of site waters and, as such, are
not recommended. All storm/site water drainage pipes should be in conformance with the
requirements of Table 1102.5 of the 2016 California Plumbing Code.
Unlined flowerbeds, planters, and lawns should not be constructed against the perimeter of the
structure. If such landscaping ( against the perimeter of a structure) is planned, it should be properly
drained and lined or provided with an underground moisture barrier. Irrigation should be kept to a
minimum.
The CBC recommends five percent slope away from structures for landscape areas within ten feet
of the residence. Hardscape areas shall be sloped a minimum of two percent where within ten feet
PA2019-264
COAST GEOTECHNICAL, INC.
Nicholson Companies
Geotechnical Engineering Investigation
14 w. 0. 584919-01
December 2. 2019
of the residence unless allowed otherwise by the building official. Minimum drainage shall be one
percent for hardscape areas and two percent for all other areas.
We do not recommend the use of infiltration best management practice (BMP) such as bottomless
trench drains, infiltration trenches, infiltration basins, dry wells, permeable pavements or similar
systems designed primarily to percolate water into the subsurface soils within five feet of
foundations. Due to the physical characteristics of the site earth materials, infiltration of waters into
the subsurface earth materials has a risk of adversely affecting below grade structures, building
foundations and slabs, and hardscape improvements. From a geotechnical viewpoint surface
drainage should be directed to the street.
The WQMP requirement shall be addressed by the Civil Engineer.
ENGINEERING CONSULTATION, TESTING & OBSERVATION
We will be pleased to provide additional input with respect to foundation design once methods of
construction have been determined.
Grading, foundation and shoring plans should be reviewed by this office prior to commencement of
grading so that appropriate recommendations, if needed, can be made.
Areas to receive fill should be observed when unsuitable materials have been removed and prior to
placement of fill. Fill should be observed and tested for compaction as it is placed.
SUPPLEMENTAL CONSULTING
During construction, a number of reviews by this office are recommended to verify site
geotechnical conditions and conformance with the intentions of the recommendations for
construction. Although not all possible geotechnical observation and testing services are required.
The following site reviews are advised, some of which will probably be required by the City of
Newport Beach:
■ Grading and excavations review for main structures
• Foundation excavations
■ Slab subgrade compaction testing
■ Slab steel placement, primary and appurtenant structures
■ Compaction of utility trench backfill
■ Hardscape subgrade compaction
AGENCY REVIEW
All soil, geologic and structural aspects of the proposed development are subject to the review and
approval of the governing agency(s). It should be recognized that the governing agency(s) can
dictate the manner in which the project proceeds. They could approve or deny any aspect of the
proposed improvements and/or could dictate which foundation and grading options are acceptable.
PA2019-264
COAST GEOTECHNICAL, INC.
Nicholson Companies
Geotechnical Engineering Investigation
15 w. 0. 584919-01
December 2, 2019
Supplemental geotechnical consulting in response to agency requests for additional information
could be required and will be charged on a time and materials basis.
LIMITATIONS
This report presents recommendations pertaining to the subject site based on the assumption that
the subsurface conditions do not deviate appreciably from those disclosed by our exploratory
excavations. Our recommendations are based on the technical information, our understanding of the
proposed construction, and our experience in the geotechnical field. We do not guarantee the
performance of the project, only that our engineering work and judgments meet the standard of care
of our profession at this time.
In view of the general conditions in the area, the possibility of different local soil conditions may
exist. Any deviation or unexpected condition observed during construction should be brought to the
attention of the Geotechnical Engineer. In this way, any supplemental recommendations can be
made with a minimum of delay necessary to the project.
If the proposed construction will differ from our present understanding of the project, the existing
information and possibly new factors may have to be evaluated. Any design changes and the
finished plans should be reviewed by the Geotechnical Consultant. Of particular importance would
be extending development to new areas, changes in structural loading conditions, postponed
development for more than a year, or changes in ownership.
This report is issued with the understanding that it is the responsibility of the owner, or of his
representative, to ensure that the information and recommendations contained herein are called to
the attention of the Architects and Engineers for the project, and incorporated into the plans and that
the necessary steps are taken to see that the contractors and subcontractors carry out such
recommendations in the field.
This report is subject to review by the controlling authorities for this project.
We appreciate this opportunity to be of service to you.
Respectfully submitted:
COAST GEOTECHNICAL, INC.
Ming-Tarng Chen
RCE 54011
PA2019-264
COAST GEOTECHNICAL, INC.
Nicholson Companies 16
Geotechnical Engineering Investigation
APPENDIX A
w. 0. 584919-01
December 2, 2019
This appendix contains a description of the field investigation, laboratory testing procedures and
results, site plan, exploratory logs and expansive soil recommendations.
FIELD INVESTIGATION
The field investigation was performed on November 1 & 5, 2019, consisting of the excavation of a
boring by a limited access drilling equipment (for Boring No. 1) and a boring by hand auger
equipment (for Boring No. 2) at the locations shown on the attached Topographic Survey Plan. As
drilling progressed, personnel from this office visually classified the soils encountered, and secured
representative samples for laboratory testing.
Description of the soils encountered is presented on the attached Boring Logs. The data presented
on this log is a simplification of actual subsurface conditions encountered and applies only at the
specific boring location and the date excavated. It is not warranted to be representative of
subsurface conditions at other locations and times.
LABORATORY TESTING
Field samples were examined in the laboratory and a testing program was then established to
develop data for preliminary evaluation of geotechnical conditions.
Field moisture and dry densities were calculated for each undisturbed sample. The samples were
obtained per ASTM:D-2937 and tested under ASTM:D-2216.
Maximum density-optimum moisture relationships were established per ASTM:D-1557 for use in
evaluation of in-situ conditions and for future use during grading operations.
Direct shear tests were performed in accordance with ASTM:D-3080, on specimens at near
saturation under various normal loads. The results of tests are based on an 80% peak strength or
ultimate strength, whichever is lower, and are attached as Plates D and E.
Expansion tests were performed on typical specimens of nahrral soils in accordance with the
procedures outlined inASTM:D-4829.
A consolidation test was performed on representative samples based on ASTM:D-2435. The
consolidation plot is presented on Plate F.
PA2019-264
COAST 0EOTECHNICAL, INC.
Nicholson Companies 17
Geotechnical Engineering Investigation
TEST RESULTS
Maximum Density/Optimum Moisture (ASTM: D-1557)
Direct Shear (ASTM: D3080)
1 0 - 5 (remolded) 100 32
2 3 50 31
Expansion Index (ASTM: D4829)
Soluble Sulfate Analysis (USEPA Method 375.4)
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December 2. 2019
PA2019-264
NEWPORTBEACHQUADRANGLE
CALIFORNIA -ORANGE CO.
7.5 MINUTE SERIES (TOPOGRAPIDC)
SITE VICINITY MAP
Geotechnical Engineering Investigation
5009 Seashore Drive
Newport Beach, California
UNITED STATES
DEPARTMENT OF THE INTERIOR
GEOLOGIC SURVEY
Work Order 584919
Plate No. 1
COAST GEOTECHNICAL, INC.
PA2019-264
SITE PLAN
Seashore Drive
RclM SURVEYING INC.
RON MICDEKA L,S. ◄6:SJ
23016 LAKE: F'DREST DR. •409
LAGUNA HILLS, CA 9<!6,J cg,19, sss-292,4 arnce:
C9◄
9
>
858-3438 fAX
RIIHSI.RVEYIN:ilCOx.N£T
Geotechnical Engineering Investigation
5009 Seashore Drive
Newport Beach, California
Scale: 1" ~ 10'
Work Order 584919
Plate No. 2
COAST GEOTECHNICAL, INC.
PA2019-264
SEISMIC HAZARD ZONES MAP
26
STATE OF CALIFORNIA
SEISMIC_ HAZARDS ZONES
'1>911nNtad In compUanca with
Chaptei-7.S. Dlvldon 2 of th• CallfomJ ■ PubDo RHourcn Code
· .. · {s.lsmk l{aurd,_Mapplng .kt/ ..
. NEWPORT B~CH QUADRANGLE
OFFICIAL MAP
Liquefaction Zona Released: April 7, 1997
Landslide Zona Released: Aprll 15, 1998
Geotechnical Engineering Investigation
5009 Seashore Drive
Newport Beach, California
Zones of Required Investigation:
Llquaf~ctlon .
Areas where historic occurri!nce of DquefactJon, or local geological, .
gootec;hnlcal and groundwater oondiUons lndlcate'a polen1lal for
permenert ground displacements such that miUgallon as defined Ir>
Public Resources Code Section 2693{c) would be mqulred. '
E,arthquako,-fnduced Landsffdes
Areas where prevtoue occurrence of lands/Ide mcwenieirt, or local
topographic, geological, geotechnlcat and subsurtace water condlllcins
Indicate a potential for permanent grourd displacements such that
miUgatlon as defined In PtJbllc Resources Code Section 2693{c) v.ould
be requlrad.
Work Order 584919
Plate No. 3
COAST GEOTECHNICAL, INC.
PA2019-264
TEMPORARY EXCAVATION ALONG PROPERTY LINES
BUILDING
FACE
NEW
FOOTING
(24")
F.F.
1
/
/
I'
SCALE: 1",;;:; 2'
WALL
ORP.L.
/I /
// l~MPORARY ,f-----;Y SLOPE
/1 /
// ! ~ BENCHING
7
----___ _,L ______ !,11 ~
1:1 PROJECTION
OVER-EXCAVATION
This plate is not a representation of actual site conditions. It is a
general representation of typical conditions and intended for the
illustration of geotechnical data only. The indicated scale is
approximate, and to be used for rough measurement only.
Geotechnical Engineering Investigation
5009 Seashore Drive
Work Order 584919
Newport Beach, California Plate No. 4
COAST GEOTECHNICAL, INC.
PA2019-264
POTENTIAL TSUNAMI RUNUP INUNDATION CAUSED BY A
SUBMARINE LANDSLIDE
/'
.,, ✓, ~"'
,.,"'"' d• ' -~
'· 4· '" ' .. "
' Ba,e Map: USCS Topographic Map from Su~!MAPS RASTER '
~•eao:h by J.C. Borr,,ro and otheri at Univeriity of
Southern Californ la
Seale: 1 :60,000
•,.-'...,...,•...,...,~••.•_. __ ...,.,,,,.,1,5 Mile£
Source: City of Ne:wpo rt Bea:h, 2007 ba.ed on unpubli,hed ""'
NOTES:
lhis rnap ii inbard.;i:fforpi.;:ral la.nd u=:planni11: only. lnforrniiLl:ion0nthiil n-gp is; rd
suficia:rt bo ~Mi: ;z; asut:151:itl.G t\:::ird;;taibd z;:obz,k:: iw,;stip.tbrmof indivkfualst.;;r
nor do= it:iiiiilti:ilyth,a: ,;r.,._luation r,;:qu i,a;m'li:rtll NI: forth in z,;olozic ha.z::a.rd rquli&t ions.
·~,
"-··-
EXPLANATION
Buth Corr..ub.nl:5111:Qrn:a.tion:z.1 (EC~ ma.bas no ri;p~ntuion; ory.,ariantk::!: l'Q2?,r:iin3:
thriia.o=u~ dtbiidata.from which th;s,;: fl'RPS\,11,;:N:dr;:~. Ec:lshall net b;: liabla
un:IQr a.ny cl cu m:t:ano=:= fc1r a.11/ d lrcd,,. lndl JKt.. ~iaL lncida:nta.L ar COM!D;QUG:rt ia.l
da.m;.p wlh ~ lna.nycla.im bya.ny 1&;:rorthirdpatyan iil.oXOUrtof.ora.risiJPi
f11m,.thQ11000fthi; ""Pl
-~ E8!11t ~
Project Number: 2706
Date: 2006
Geotechnical Engineering Investigation
5009 Seashore Drive
Newport Beach, California
...... ..
Area that would be inundated by a
tiunami generated by a 1ubmarine
landslide offshore of Newport Beach
(areas at or lower than 32 foot elevation
Newport Beach City Boundary
---Sphere of Influence
Work Order 584919
Plate No. 5
COAST GEOTECHNICAL, INC.
PA2019-264
UNIFIED SOIL CLASSIFICATION AND KEY TO BORING LOGS
UNITED SOIL CLASSIFICATION SYSTEM (ASTM D-2487)
PRIMARY DIVISIONS SYMBOLS SECONDARY DIVISIONS
GW WELL-GRADED GRAVELS, GRAVEL-SAND MIXTURES, LITTLE
GRAVEL AND CLEAN GRAVELS ORNO FINES
GRAVELLY (LITTLE OR NO
SOILS FINES) GP POORLY-GRADED GRAVELS, GRAVEL-SAND MIXTURES,
COARSE LITTLE OR NO FINES
GRAINED SOILS MORE THAN 50%
OF COARSE GRAVELS WITH GM SILTY GRAVELS, GRAVELS-SAND-SILT MIXTURES
FRACTION FINES
RETAINED ON (APPRECIABLE
N0.4SIEVE AMOUNT OF FINES) GC CLAYEY GRAVELS, GRAVELS-SAND-CLAY MIXTURES
SW WELL-GRADED SANDS, GRAVELLY SANDS, LITTLE OR NO
SAND AND CLEAN SAND FINES
SANDY SOILS (LITTLE OR NO
MORE THAN 50% FINES) SP POORLY-GRADED SANDS, GRAVELLY SANDS, LITTLE OR NO
OF MATERIAL IS FINES
LARGER THAN NO. MORE THAN 50%
200 SIEVE SIZE OF COARSE SAND WITH SM SIL TY SANDS, SAND-SILT MIXTURES
FRACTION FINES
PASSING NO. 4 (APPRECIABLE
SIEVE AMOUNT OF FINES) SC CLAYEY SANDS, SAND-CLAY MIXTURES
INORGANIC SIL TS AND VERY FINE SANDS, ROCK FLOUR,
ML SILTY OR CLAYEY FINE SANDS OR CLAYEY SILTS WITH
SLIGHT PLASTICITY
FINE GRAINED SILTS AND LIQUID LIMIT INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY,
SOILS CLAYS LESS THAN 50 CL GRAVELLY CLAYS, SANDY CLAYS, SIL TY CLA VS, LEAN
CLAYS
OL ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW
PLASTICITY
MH INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE
MORE THAN 50% SAND OR SIL TY SOILS
OF MATERIAL IS SILTS AND LIQUID LIMIT
SMALLER THAN CLAYS GREATER THAN CH INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS
NO. 200 SIEVE 50
SIZE OH ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY,
ORGANIC SIL TS
HIGHLY ORGANIC SOILS PT ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW
PLASTICITY
COARSE GRAINED SOILS FINE GRAINED SOILS
CONSISTENCY BLOWS/FT' CONSISTENCY BLOWS/FT'
VERY LOOSE 0-4 VERY SOFT 0-2
LOOSE 4-10 SOFT 2-4
MEDIUM DENSE 10-30 FIRM 4-8
DENSE 30 • 50 STIFF 8-15
VERY DENSE OVER50 VERY STIFF 15-30
HARD OVER30
" BLOWS/FT FOR A 140-POUND HAMMER FALLING 30 INCHES TO DRIVE A 2 INCH O.D., 1-3/8 INCH I.D. SPLIT
SPOON SAMPLER (STANDARD PENETRATION TEST)
KEY TO SAMPLE TYPE: U = UNDISTURBED SAMPLE B= BULK S = SPT SAMPLE
COAST GEOTECHNICAL, INC.
PA2019-264
COAST GEOTECHNICAL, INC.
(Text Supercedes)
PLATEA
12" 12" 12" 15" 15"
15" 15" 15" 15" 15"
18" 18" 18" 18" 18"
24" 24" 24" 24" 30"
24" 24" 24" 24" 36"
24" 24" 24" 24" 30"
24" 24" 24" 24" 36"
4 #5 Bars 4 #5 Bars 4#5 Bars 4#5 Bars 4 #5 Bars
2Top 2Top · 2Top 2 Top 2Top
2 Bottom 2 Bottom 2Bottom 2 Bottom 2Bottom
5" Actual 5" Actual 5" Actual 5" Actual 5" Actual
#4 Bars on #4 Bars on #4 Bars on #4 Bars on #4Bars on
12" 12" 12" 12" 12"
Centers Both Centers Both Centers Both Centers Both Centers Both
Ways Ways Ways Ways Ways
15 mil 15 mil 15 mil 15 mil 15 mil
Membrane Membrane Membrane Membrane Membrane
#4 Bars on #4 Bars on #4Bars on #4Bars on #4 Bars on
12" 12" 12" 12" Center 12" Center
Centers Both Centers Both Centers Both Both Ways Both Ways
Ways Ways Ways Free Floating Free Floating
Same as Adj. Same as Adj. Same as Adj. Same as Adj. Same as Adj.
Ext. Ftg. Ext. Ftg. Ext. Ftg. Ext. Ftg. Ext. Ftg.
4" Clean 4" Clean 4" Clean 4" Clean 4" Clean
Aggregate Aggregate Aggregate Aggregate Aggregate
Above Opt. 110% of Opt 130% of Opt 130% of Opt
To M/Cto MIC to Depth MIC to Depth
Depth ofFtg. Depth Footing Footing
(No Testing) Footing
1. Basement slabs shall have a minimum thickness of six inches.
2. Floor slab shall be constructed over a 15 mil plastic membrane. The membrane shall be properly lapped, sealed and in
contact with the slab bottom.
3. Aggregate should be ½-inch or larger.
PA2019-264
Date:
Q)
I-2 a. ro
Cl) > z
15
16
31
41
15
SUMMARY OF BORING NO. 1
11/5/2019 Elevation: E.G.
,-.. en ,-.. >,
Q) ..... (.)
+-' Q) ..... C:
C en 5$ C. LL L.. Q)
Q) Q) -0 +-' e c: 1i5 i::' E .c:: Description 0 (/)
ro +-' 'iii Q) ·-·o o c.. (.) a.. LL ~ ~ Cl) Q) C:
0 0 e..., U B (.)
Asphaltic Concrete (5")
FILL: SAND ---silty, medium-grained, dry to damp, Tan to Tan Medium
with gravel Brown Dense
NATIVE: SAND ---clean, fine to medium-grained, Tan to Light Medium
dry to damp Gray Tan Dense
SAND ---clean, fine to medium-grained, dry to Tan to Light Medium
3 2.9 damp Gray Tan Dense
5
SAND ---clean, medium-grained, damp to moist, Tan to Tan Medium
2 5.9 with shells Brown Dense
SAND ---coarse-grained, very moist to wet, with Tan To Tan Dense
4 15.5 pebbles Brown
SAND ---coarse-grained, wet, with pebbles Tan to Tan Dense
5 16.4 10 Brown
SAND ---coarse-grained, wet, with pebbles Tan to Tan Medium
4 15.1 Brown Dense
End of boring at 12.5 feet
Groundwater at 7.0 feet
Sands are subject to caving
15
Geotechnical Engineering Investigation
5009 Seashore Drive
Work Order 584919
Newport Beach, California Plate B
COAST GEOTECHNICAL, INC.
PA2019-264
SUMMARY OF BORING NO. 2
Date: 11/1/2019 Elevation: E.G.
~ -en ->,
~~ CJ "cii (I) ....: C
Cc;::-a. u.. L.. 2 .__, 0 (I) CJ en ~ E .c Description 0 Cl) 0 0. ·o o co -"cii ~ .__, Cl) 0.. () C ~~ (I) 0 0 e..... 0 ()
U B
Concrete (4")
FILL: SAND ---fine to medium grained, dry to Light Gray Loose
damp, with shells Tan to Light -Tan
2
NATIVE: SAND ---clean, medium-grained, dry to Yellow Tan Medium
damp Dense
-
100.4 2.9
4 -
SAND ---clean, fine to medium-grained, damp Light Gray Medium
Tan Dense
-
101.4 5.7
6 -
-
101.9 9.8 SAND ---clean, medium to coarse-grained, moist Gray Tan Medium
to wet Dense
8
End of boring at 8.0 feet
Groundwater at 7.5 feet
-Sands are subject to caving
10-
-
Geotechnical Engineering Investigation Work Order 584919
5009 Seashore Drive
Newport Beach, California Plate C
COAST GEOTECHNICAL, INC.
PA2019-264
SHEAR TEST RESULT
[ Boring No.1 @Oto 5 Feet (Remolded to 90%) )
5 ..------.----.----~----,-----,
4 1------+----t-----t---------,1-------1
-~ 3 c:i-en --en
C. g
gi
~ 2
u5
0
0 1 2 3 4 5
Confining Pressure (kips/sq. ft.)
Remolded soil samples were tested at saturated conditions.
The sample had a dry density of 100.9 lbs./cu.ft. and a moisture content of 24.6 %.
Cohesion = 100 psf
Friction Angle = 31 degrees
Based on 80% peak strength or ultimate strength, whichever is lower
Geotechnical Engineering Investigation
5009 Seashore Drive
Work Order 584919
Newport Beach, California Plate No. D
COAST GEOTECHNICAL, INC.
PA2019-264
SHEAR TEST RESULT
Boring No. 2 @ 3.0 feet l
5
4
-.::: 3 &
1/)
]_
g
gJ
~ 2
ci5
0 1 2 3 4 5
Confining Pressure (kips/sq. ft.)
Native soil samples were tested at saturated conditions.
The sample had a dry density of 100.4 lbs./cu.ft. and a moisture content of 24.9 %.
Cohesion = 50 psf
Friction Angle = 31 degrees
Based on 80% peak strength or ultimate strength, whichever is lower
Geotechnical Engineering Investigation
5009 Seashore Drive
Work Order 584919
Newport Beach, California Plate No. E
COAST GEOTECHN/CAL, INC.
PA2019-264
CONSOLIDATION TEST RESULTS
[ Boring No. 2 @ 3.0 Feet l
Pressure (Kips Per Square Foot)
0.1 1 10
0.00
n....
,-.
-._
1.00 -... -.......... -..........
r-.... '
2.00 ..... r-.. -' ---" ~ I'---' 3.00 --C
G)
~ 4.00 -
G) a. -C:
0 5.00 ; ca
:'S!
0
U) 6.00
C:
0
0
7.00
8.00
9.00
10.00
0 Test Specimen at In-Situ Moisture
• Test Specimen Submerged
Geotechnical Engineering Investigation Work Order 584919
5009 Seashore Drive
Newport Beach, California Plate No. F
COAST GEOTECHNICAL, INC.
PA2019-264
ALLOWABLE BEARING CAPACITY
Bearing Capacity Calculations are based on "Terzaghi's Bearing Capacity Theory"
Bearing Material: Compacted Fill
Properties:
Wet Density (y) = 110 pcf
Cohesion (C) = 100 psf
Angle of Friction (¢) = 31 degrees
Footing Depth (D) = 2 feet
Footing Width (B) = 1.3 feet
Factor of Safety = 3.0
Calculations -Ultimate Bearing Capacity
from Table 3.1 on page 127 of "Foundation Engineering Handbook", 1975
Ne= 32.67 Nq = 20.63 Nr = 25.99
Ou = 1.3 C Ne + y D Nq + 0.4 y B Ny (Square Footing)
= 1.3 * 100 * 32.67 + 110 * 2 * 20.63 + 0.4 * 110 * 1.25 * 25.99
= 4247 + 4538 + 1429 = 10214 psf
Allowable Bearing Capacity for Square Footing
Oau= Ou/ F.S. = 3404 psf
Use 1800 psf
Ou= 1.0 C Ne+ y D Nq + 0.5 y B Ny (Continuous Footing)
= 1.0 * 100 * 32.67 + 110 * 2 * 20.63 + 0.5 * 110 * 1.25 * 25.99
= 3267 + 4538 + 1786 = 9591 psf
Allowable Bearing Capacity for Continuous Footing
Oa11 = Ou/ F.S. =
Use 1800 psf
3197 psf
Geotechnical Engineering Investigation
5009 Seashore Drive
Work Order 584919
Newport Beach, California Plate G
COAST GEOTECHNICAL, INC.
PA2019-264
LATERAL EARTH PRESSURE CALCULATIONS
Retaining structures such as retaining walls, basement walls, and bulk-heads are commonly
used in foundation engineering, and they support almost vertical slopes of earth masses.
Proper design and construction of these structures require a through knowledge of the lateral
forces acting between the retaining structures and the soil masses being retained. These
lateral forces are due to lateral earth pressure.
Properties of earth material: Compacted fill
Wet Density (y)
Cohesion (C)
=
=
110 pcf
100 psf
Angle of Friction(¢) = 31 degrees
Coefficient of Friction = tan <I>
Therefore,
Coefficient of Friction = tan <I>
= tan¢ = 0.601
Assumed H = 2 feet
Use 0.35
Pp= 0.5 y H2 tan 2 ( 45° + ¢ / 2 ) + 2 C H tan ( 45° + ¢ / 2 )
= 0.5 * 110 * 4 * 3.122 + 2 * 100 * 2 * 1. 767
= 687 + 707 = 1394 lbs/ LF
1/2 EFP H2 = 1394 EFP: passive pressure
EFP = 697 psf / LF
Allowable Passive Pressure = 300 psf / LF ( with F.S. = 2.32 )
Geotechnical Engineering Investigation
5009 Seashore Drive
Work Order 584919
Newport Beach, California Plate H
COAST GEOTECHNICAL, INC.
PA2019-264
CALCULATION OF SUBGRADE REACTION
Subgrade reaction calculations are based on "Foundation Analysis and Design" Fourth
Edition, by Joseph E. Bowles.
Ks= 24 quit (for l1H = 1/2 inch)
Where:
Ks = subgrade reaction in k / ft 3
quit = ultimate bearing capacity
For quit = 9.5 ksf (from bearing capacity calculations)
Ks = 24 * 9.5 k / ft 3
= 228* 1000 / ( 12 * 12 * 12) lb / in 3
= 131.9 lb/ in 3
Use 100 pound per cubic inch
Geotechnical Engineering Investigation
5009 Seashore Drive
Newport Beach, California
COAST GEOTECHNICAL
Work Order 584919
Plate No. I
PA2019-264
APPENDIXB
Liquefaction Analysis by SPT
Geotechnical Engineering Investigation
5009 Seashore Drive
Newport Beach, California
COAST GEOTECHNICAL, INC.
PA2019-264
LIQUEFACTION ANALYSIS BY SPT FOR BORING NO. 1 CN = (Pa/ ao' )112 < 2, Pa= 2089 psf (N1)eo = Nm CN CE Cs CR Cs CSR= rav / a0' = 0.65 ( a0 I a0') rd ( amax I g) : :J~~ ::: :::i:~1 T:~ ~I :i~::;1~111111111 ::g~11111111~~1111:~~illll1t:: :1::i~~: :::~::: ~~~ :tSIOO~~~rr~ :~~fr~~;:::::~ :: ii: 3 315.o I 315.o 15 2.00 I 1.00 I 1.05 I o.75 I 1.20 28.4 0.99 I 0.45 3 0.37 I 1.15 I 0.43 5 525.o I 525.o 16 1.99 I 1.00 I 1.05 I 0.75 I 1.20 30.2 0.99 I 0.45 2 0.60 I 1.15 I 0.69 7 775.0 I 650.2 31 1.79 I 1.00 I 1.05 I 0.75 I 1.20 52.5 0.99 I 0.53 4 0.60 I 1.15 I 0.69 9 1025.o I 775.4 41 1.64 I 1.00 I 1.05 I o.75 I 1.20 63.6 0.98 I 0.58 5 0.60 I 1.15 I 0.69 11 1275.o I 900.6 15 1.52 I 1.00 I 1.05 I o.75 I 1.20 21.6 o.98 I 0.62 4 0.24 I 1.15 I 0.28 Note: 1. Moist unit weight of 105 pcf, saturated unit weight of 125 pcf, and groundwater at 5 feet 2. Magnitude of 7.2 and peak ground acceleration of 0.692 g 3. According to Figure 7.1, soil layers having (N1)60 higher than 30 are not considered liquefiable. Geotechnical Engineering Investigation I Work Order 584919 5009 Seashore Drive Newport Beach, California COAST GEOTECHN/CAL, INC. Plate M 0.96 1.55 1.30 1.18 0.44 PA2019-264
Open-fila Aep011 97--08
L---------------------------------------' ,,.,..
OOlllllfO~Ml 11.H.U ;J'JJ1:8J-fftH.tfldt\ 'Wr'lif'lO"
• Boreholo Site .,-. 3o -Oapth to gmund w.-.ar In fool
ONEMILE
SCALE
Plate 1,2 Hlstoncally Hlghm Ground Water Cootours and Borehole Log Data Locations, Newport Beach Ollildrangl&,
PA2019-264
00 0.1 0.2 0.3 0.7 0.8 0.9 1.0
10
I
20 1
J
QJ
40[
QJ I
I
.::: 50
0.
QJ
a
60
I
70
I
I
I
I
80
I
I
'
90
100
FIG. 1 -RANGE OF VALUES OF rd FOR DIFFERENT SOIL PROFILES
PA2019-264
Recommended Procedures for Implementation of DMG Special Publication 117 Guidelines for Analyzing and
Mitigating Liquefaction Hazards in California
Table 5.2. Corrections to Field SPT N-Values (modified from Youd and Idriss, 1997)
Factor EqtiipmentV ariable Term
Overburden Pressure CN
Energy Ratio Safety Hammer c.
Donut Hammer
Automatic Trip
Hammer
Borehole Diameter 65mmto 115mm Ca
150mm
200mm
Rod Length** 3mto4m CR
4mto6m
6mto10m
10m to30m
>30m
Sampling Method Standard Sampler Cs
Sampler without liners
* The Implementation Committee recommends using a minimum of 0.4.
** Actual total rod length, not depth below ground surface
12
Correction
(P./cr'vo)°";
0.4~CN~2 *
0.60to l.17
0.45 to 1.00
0.9 to 1.6
1.0
1.05
1.15
0.75
0.85
0.95
1.0
<1.0
1.0
1.2
PA2019-264
Recommended Procedures for Implementation of DMG Special Publication 117 Guidelines for Analyzing and
Mitigating Liquefaction Hazards in California
0.6..-----.------3-7 ....... ----...-----------,
.29
Percent Fines = 35
I
I
25lll
15
0.51------+------¼.l----1--+------¼-----1 I
I
I
I
I
I
I
I
I
I
I
I
I
I
CRR curves for 5,15, and
35 percent fines, respectively
FINES CONTENT~ 5%
Modified Chinese Code Proposal (clay content= 5%) ®
Marginal No
Liquefaction Liquefaction Liquefaction
-1 Adjustment Pan -American data ■ Ill
Recommended Japanese data· • o e
By Workshop Chinese data .A A oL--..L====::;:-=!I.__...L......:.._ __ J__ __ ---1. __ =---'
0 20 30 40 50
Corrected Blow Count, (N1)60
Figure 7.1. Simplified Base Curve Recommended for Determination of CRR from SPT Data
for Moment Magnitude 7.5 Along with Empirical Liquefaction Data
(after Youd and Idriss, 1997)
50
PA2019-264
Recommended Procedures for Implementation of DMG Special Publication 117 Guidelines for Analyzing and
Mitigating Liquefaction Hazards in California
~
C/:l ::s
i-:-.s u ~
bl)
t:: .... -c-1 u
C/:l
~
"'O
E ....
C
~ ::s
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
-+-Seed and Idriss, (1982)
-+----~---...-t--~-:------"'.""""-t---rt ---Idriss
5.0
Workshop
x Ambraseys(1985)
◊ Arango (1996)
♦ Arango (1996)
_.,_ Andrus and Stokoe
• Youd and Noble, PL<20%
A Youd and Noble, PL<32%
• Youd and Noble, PL<50%
6.0 7.0 8.0 9.0
Earthquake Magnitude, Mw
Figure 7.2. Magnitude Scaling Factors Derived by Various Investigators
(After Youd and Idriss, 1997)
51
PA2019-264
APPENDIX C
Calculations of Seismically Induced Settlement
Geotechnical Engineering Investigation
5009 Seashore Drive
Newport Beach, California
COAST GEOTECHNICAL, INC.
PA2019-264
CALCULATIONS OF SEISMICALLY-INDUCED SETTLEMENT
Calculations of seismically-induced settlement for the subject site are performed based
on the 11 Evaluation Of Settlement In Sands Due To Earthquake Shaking 11 by Kohji
Tokimatsu and H. Bolton Seed, dated August 1987.
The calculations of the seismically-induced settlement are as follows:
1. Calculate the effective overburden pressure at the center of each layer.
2. The SPT N-value needs to be corrected depending on equipment used and a0'.
(N1)ao = Nm CN CE Cs CR Cs
Where CN = (Pa/ a0')
112 < 2, Pa= 2089 psf
(N 1)60 = corrected N value
Nm = field N value
CN = correction factor depending on effective overburden pressure
a0' = effective overburden pressure, in psf
3. Calculate the maximum shear modulus
Gmax
Gmax
Oo'
=
=
=
20 (N1)ao 1/3 ( Oo' ) 112
maximum shear modulus, in ksf
effective overburden pressure, in psf
4. From the depth in Figure 1, find the stress reduction coefficient, rd
5. Calculate Yeff ( Geff I Gmax )
Yetr ( Geff I Gmax) = 0.65 amax Oo rd/ ( g Gmax)
amax = 0.692 g and M = 7.2 ( for the subject site)
Yeff = effective shear strain induced by earthquake shaking
Gaff = effective shear modulus at induced strain level
( cont'd )
Geotechnical Engineering Investigation
5009 Seashore Drive
Work Order 584919
Newport Beach, California Plate N1
COAST GEOTECHNICAL, INC.
PA2019-264
CALCULATIONS OF SEISMICALLY-INDUCED SETTLEMENT
amax = maximum ground surface acceleration
a0 = total overburden pressure
g = acceleration of gravity
6. From Yetr ( Geff I Gmax) and 0 0' in Figure 2, find Yeff (cyclic shear strain)
7. From Yetr and (N 1 )60 in Figure 3, find ec.M. = 7.5 (volumetric strain due to compaction)
8. Interpolation from Table 1, ec.M. = 7.2 = 0.940 Ec.M. = 1.5
9. This settlement caused by combined horizontal motions is about equal to the sum of
the settlement caused by the components acting alone.
Calculate 2 e c.M. = 1.2
10. Calculate the total settlement
Geotechnical Engineering Investigation
5009 Seashore Drive
Newport Beach, California
Work Order 584919
Plate N2
COAST GEOTECHN/CAL, INC.
PA2019-264
SEISMICALLY INDUCED SETTLEMENT OF DRY SAND FOR BORING NO. 1 :t !!l~I!! !~I~ 111~ !!!~~! ~~I: !!~Ir!! !!!H!!i! '!~~~~:! 1!11!1!1!! :1:11!~l!l!l l~-~~i i!i!i!i!i~™!i1i1i1i i1~~tf~l i!~l~~1!1![~~t~1!i!1 1 2.0 4.0 3.0 2.0 315 315 15 28.4 1083 0.99 13.0 *10-5 32 *10-5 0.022 0.021 0.041 0.01 2 4.0 5.0 4.5 1.0 I 473 I 473 I 16 I 30.2 I 1354 I 0.99 I 15.5 *10-5 I 36 *10-5 I 0.020 I 0.019 I o.038 0.00 Based on : 1. Moist unit weight of 105 pcf, saturated unit weight of 120 pcf, and groundwater at 5 feet 2. Magnitude of 7.2 and peak ground acceleration of 0.692 g 3. Gmax = 20 (N1)so 1/3 ( ao' ) 112 4. Ye1d Geff / Gmax) = 0.65 amax ao rd I ( g Gmax) Geotechnical Engineering Investigation 5009 Seashore Drive Newport Beach, California COAST GEOTECHNICAL, INC. TOTAL 0.01 Work Order 584919 Plate No. N3 PA2019-264
-._, .,
>--
C ·-0
I.. -V1
I..
0
4,)
.r;
V1
1e5'3.
-4
10
-!> 10 ~-----------i..__.,___.,_._ ................... __ _.__.._ ___ ....._.....i.,....._-'--__ _.__,J
10-5 10-4
Yaff (Get f / Gma,r.)
FIG. ·2 -PLOT FOR DETERMINATION OF INDUCED STRAIN
IN SAND DEPOSITS
PA2019-264
Cyclic Shear S1rain, r.. -percent
lo
_-.. 2 xy I
..J 10-10·
10"3 r---y---r--r-,----r--.--r--r-~--r----.--..--.-------:
C -2 "'15
~10 :::::10
'-
CJ
Q.
I
u :::::5
w
C
0
u
0
0. ~ 10 1
u
0 -
tJ
::l
Q
C:
0
"--V,
-~ '--~ :,
-j
'
'\
'
' '
'
' '
' ' ' '
' ' '
'
' '
' ' ' '
' ' '
' ' ' '
' ' ' ' '
' '
' '
' ' '
' ' '
'
'
IS Cycles
' ' ' ' '
' ' ' ' '
' '\
' '\
' '
' '
' ' '
' .... ......
FIG.3. -RELATIONSHIP BETWEEN VOLUMETRIC STRAIN, SHEAR STRAIN,
AND PENETRATION RESISTANCE FOR DRY SANDS
PA2019-264
TABLE 1 -INFLUENCE OF EARTHQUAKE MAGNITUDE ON VOLUMETRIC
STRAIN RATIO FOR DRY SANDS
Earthquake
magnitude
(1)
8-1/2
7-1/2
6-3/4
6
5-1/4
Number of representative
cycles at 0.65 '!"max
(2)
26
15
10
5
2~3
Volumetric strain ratio,
Ec,N / Ec,-N-1s
(3)
1.25
1.0
0.85
0.6
0.4
PA2019-264
SEISMICALLY INDUCED SETTLEMENT OF SATURATED SOILS FOR BORING NO. 1 illl~ll llll;~ll lil111[~1!1! t!!lll!li!! li!II!!! illl~II !lllli!~tli!ilil!!l!i!!~i!!!!i!l!!llli~ii ill!illi~illill!~liil!lli!!!iil~~lllil !ll~l!lllllllll~~!ll~I 1 5.0 6.0 1.0 I 30.2 2 o.oo I 1.00 30.2 0.45 2 6.0 8.0 2.0 I 52.5 4 o.oo I 1.00 52.5 0.53 3 8.0 10.0 2.0 I 63.6 5 o.oo I 1.00 63.7 0.58 4 10.0 12.0 2.0 I 21.6 4 o.oo I 1.00 21.6 0.62 Note: 1. Groundwater at 5 feet, magnitude of 7.2, and peak ground acceleration of 0.692 g 2. (N1 }50 cs = a + /3 (N1)60 3. For volumetric strain refer to Figure 7 .11 Geotechnical Engineering Investigation 5009 Seashore Drive Newport Beach, California COAST GEOTECHNICAL 1.15 0.39 0.6 0.07 1.15 0.46 0.0 0.00 1.15 0.50 0.0 0.00 1.15 0.54 1.5 0.36 TOTAL 0.43 Work Order 584919 Plate No. 0 PA2019-264
\., ...,._
Thomas F. Blake (Fugro-West, Inc., Ventura, Calif., written commurt.) approximated the simplified
base curve plotted on Figure 2 by the following equation:
a + ex + ex 2 + gx 3
CRR 7 5 = ----------
. 1 + bx + dx 2 + .fx 3 + hx 4
(4)
where CRR75 is the cyclic resistance ratio for magnitude 7.5 earthquakes; x = (N 1)60 ; a= 0.048; b
= -0.1248; c = -0.004721; d = 0.009578; e = 0.0006136; f= -0.0003285; g = -l.673E-05; and h =
3. 714 E-06. This equation is valid for (N 1)60 less than 3 0 and may be used in spreadsheets and other
analytical techniques to approximate the simplified base curve for engineering calculations.
Robertson and Wride (this report) indicate that Equation 4 is not applicable for (N 1)60 less than three,
but the general consensus of workshop participants is that the curve defined by Equation 4 should
be extended to intersect the intercept at a CRR value of about 0.05.
Correlations for Fines Content and Soil Plasticity
Another change was the quantification of the fines content correction to better fit the empirical data
and to support computations with spreadsheets and other electronic computational aids. In the
original <;levelopment, Seed et al. (1985) found that for a given (N 1)60 , CRR increases with increased
fines content. It is not clear, however, whether the CRR increase is because of greater liquefaction
resistance or·, smaller penetration resistance as a consequence of the general increase of
compressibility and decrease of permeability with increased fines content. Based on the empirical
data available, Seed et al. developed CRR curves for various fines contents as shown on Figure 2.
After a lengthy review by the workshop participants, consensus was gained that the correction for
fines content should be a function of penetration resistance as well as fines content. The participants
also agreed that other grain characteristics, such as soil plasticity may affect liquefaction resistance;
hence any correlation .based solely on penetrationresistance and fines content should be used with
t!ngineering judgement. and caution. The following equations, developed by I.M. Idriss with
assistance from R.B. Seed are recommended for correcting standard penetration resistance
determined for silty sands to an equivalent clean sand penetration resistance:
(5)
where o: and pare coefficients determined from.the following equations:
a=0 forFC ~ 5% (6a)
a= exp[l.76-(190/FC2)] for 5% <FC <35% (6b)
a c: 5.0 forFC ~ 35% (6c)
P= 1.0 . forFC ~ 5% (7a)
p = [0.99 + (FC 1·5/1000)] for 5% < FC < 35% (7b)
p = 1.2 for FC ~ 35% (7c)
where FC is the fines content measured from laboratory gradation tests on retrieved soil samples.
7
PA2019-264
Recommended Procedures for Implementation of DMG Special Publication 117 Guidelines for Analyzing and
Mitigating Liquefaction Hazards in California
0.6r------,-------.----,-----~------
Volumetric Strain-%
0.5 10 5 4 3 2 0.5
I
I
0.4
_Iay_
cr;.' 0
0.3
0.2
·0.1
I
I
I
I
I
)
/,0.2
I I
I I
I I
I //p.1
I I I
I I I
I ·/ I I I
I I I
/ I I
'/ /. I
I I
I I
I I
I I I /
I I
I I
/ I
/ /
/ / / ,,
/ ,,
/ I / ,, /.,,,,
I/
/I
II
'//
'/;'
1//
1/1'
1/
10 20 30 40 50
Figure 7.11. Relationship Between Cyclic Stress Ratio, (N,)60 and Volumetric Strain
for Saturated Clean Sands and Magnitude= 7.5 (After Tokimatsu and Seed, 1987)
60
PA2019-264
5009 Seashore Dr, Newport Beach, CA 92663, USA
Latitude, Longitude: 33.6222336, -1 17.9428633
Date
Design Code Reference Document
Risk Category
11/20/2019, 2:23:17 PM
ASCE?-10
II
Site Class
Type
Ss
S1
SMs
SM1
Sos
So1
Type
soc
Fa
Fv
PGA
FPGA
PGAM
TL
SsRT
SsUH
SsD
S1RT
S1UH
S1D
PGAd
CRs
CR1
Value
1,693
0.626
1.693
0.94
1.129
0,626
Value
D
1.5
0.692
0,692
8
1,693
1.873
3.323
0.626
0.68
1.137
1,223
0.904
0.921
Description
MCER ground motion . (for 0 .2 second period)
MCER ground motion. (for 1.0s period)
Site-modified spectral acceleration value
Site-modified spectra l acceleration value
Numeric seismic design value at 0.2 second SA
Numeric seismic design value at 1.0 second SA
Description
Seismic design category
Site amplification factor at 0.2 second
Site amplification factor at 1.0 second
MCEG peak ground acceleration
Site amplification factor at PGA
Site modified peak ground acceleration
Long-period transition period in seconds
Probabilistic risk-targeted ground motion . (0.2 second)
D -Stiff Soil
Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration
Factored deterministic acceleration value. (0.2 second)
Probabilistic risk-targeted ground motion . (1 .0 second)
Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration.
Factored deterministic acce leration value . (1 .0 second)
Factored deterministic acceleration value. (Peak Ground Acceleration)
Mapped value of the risk coefficient at short periods
Mapped value of the risk coefficient at a period of 1 s
OSHPD
PA2019-264
MCER Response Spectrum
2.0
1.5
1.0
0.5
0.0
0.0 2.5 5.0
Period, T (sec)
-Sa(g)
Design Response Spectrum
1.5
1.0
0.5
0.0
0.0 2.5 5.0
Period, T (sec)
-Sa(g)
7.5
7.5
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PA2019-264