HomeMy WebLinkAbout20210223_Geotechnical Investigation_1-28-202123 Corporate Plaza, Suite 150, Newport Beach, CA 92660 Phone 949 629 2539 | Email info@Rmccarthyconsulting.com
January 28, 2020
Nanci and Jim Irwin File No: 8527-00 13 Beacon Bay Report No: R1-8527
Newport Beach, California 92660
SUBJECT: Geotechnical Investigation
Proposed Custom Home
13 Beacon Bay
Newport Beach, California
APN: 050-222-11
Legal Description: Lot 13 as per Map Record in R.S.B. 9, pages 42-43, in
the Office of County Recorded of Said County.
INTRODUCTION
This report presents the results of our geotechnical investigation for the project site located at 13
Beacon Bay in Newport Beach, California, which was performed to determine various site and
regional geotechnical conditions pertinent to the construction currently proposed for the subject
property. Analyses for this investigation are based upon preliminary plans and a verbal description
of the project as a new single-family residence. The property presently includes a two-story
residence with attached garage. The purpose of our review and investigation was to evaluate the
subsurface conditions, determine the compatibility of the proposed development with respect to
the geotechnical features of the site, and provide preliminary geotechnical recommendations and design parameters for site precise grading and planned improvements. Specific information and
recommendations for site development are provided herein.
The conclusions and recommendations of this report are considered preliminary due to the
absence of specific foundation and grading plans, the preparation of which are partially
dependent upon recommendations presented herein.
Project Authorization
The work performed was per your request and authorization based on our Proposal No: P1-
8527, dated January 2021.
Scope of Investigation
The investigation included the following:
R McCARTHY
-C □NSULTING, INC
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1. Review of collected geologic, geotechnical engineering and seismological reports
and maps pertinent to the subject site. A reference list is included in Appendix A.
2. Subsurface exploration consisting of one boring advanced to a depth of 14.5 feet by
use of a Tripod drill rig and one hand auger boring advanced to a depth of 6.5 feet.
The boring locations are shown on the Geotechnical Plot Plan, Figure 1.
3. Logging and sampling of the exploratory borings, including collection of soil samples
for laboratory testing. The logs of the boring explorations are included in
Appendix B.
4. Laboratory testing of soil samples representative of subsurface conditions. The
results are presented in Appendix C.
5. Geotechnical engineering and geologic analyses of collected data, including a
shallow liquefaction analysis and seismic settlement analysis.
6. Preparation of this report containing our geotechnical recommendations for the design and construction in accordance with the 2019 California Building Code (CBC)
and for use by your design professionals and contractors.
Site Description
The subject property is located on the south side of Beacon Bay, south of Harbor Island Drive,
near the terminus of Shelter Cove as shown on the Location Map, Figure 2. The property is bordered on the east and west by developed residential properties. The southern property line
fronts a public beach and the Balboa Island North Channel. The front of the house is
approximately 50 feet north of the channel.
The Topographic Map prepared by Apex Land Surveying Inc. (Reference 1) indicates that the
lot has a rectangular shape. The topographic plan was used as a base map for our Geotechnical
Plot Plan, Figure 1. Based on the topographic plan, the lot area is 4,000 square feet. Elevations vary from approximately 9 to 10 feet (NAVD88). The beach slope from the back of the lot to the
channel has a gradient of approximately 6:1 (horizontal: vertical).
The adjoining property on the east is at a similar elevation as the subject site, within
approximately 1/2 foot. The adjoining property on the west is approximately 2.5 feet higher in
elevation with the vertical offset accommodated by a block retaining wall.
The site presently contains a two-story residence with an attached garage. The house is
primarily surrounded by hardscape with the exception of a few planter areas. At the southern
property line, the rear patio abuts the public sand beach which extends approximately 50 feet
south to the channel. Hardscape includes both concrete and brick walkways and patio areas.
Vegetation is limited to vines and small plants/shrubs within planters and potted plants. The
western block wall is vine covered.
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Drainage appears to be moderately developed. Rain gutters are present on the house and down spouts empty directly to the side yards. No area drains were observed. No obvious signs of
drainage problems were observed.
Perimeter fencing includes a block retaining wall on the west property line and a vinyl fence on
the east property line. Minor concrete cracking and patio separations were observed. The
condition of the house appeared commensurate with age of the structure.
Proposed Development
We understand that the proposed development will consist of the construction of a new single-
family custom home. Preliminary plans indicate that the structure may be three-story. Grading
is expected to consist of reprocessing surface soils following removal of existing foundation
elements, unsuitable fill, weathered soil, planter soils and materials disturbed by demolition.
Overexcavation and replacement of soil as densified engineered fill is recommended to provide
uniform soil conditions within the upper materials below the structure. Structural loads were not
provided. We anticipate wood-frame and light steel construction that is typical of the area and
relatively light construction loads. We assume that maximum column loads will be less than 25
kips and wall loads of 2 kip/foot. Our office should be notified when the structural design loads for foundation elements are available to check these preliminary assumptions.
GEOTECHNICAL CONDITIONS
Geologic Setting
The property is situated within the southeasterly edge of the Los Angeles Basin along a peninsula between the Promontory Bay and the Balboa Island North Channel within Newport
Harbor. The Pacific Ocean is about 0.6 mile southwest of the site. This area is generally
underlain by sandy marine deposits. Our investigation primarily encountered medium dense to
dense sands below the site. Historical topographic maps and accounts indicate that the small
peninsula was formerly a low-lying, intertidal sand bar in the natural bay. The site is thought to
be resting on a regionally extensive, relatively flat bench scoured by wave activity into bedrock.
The bedrock lies below successive layers of beach and bay deposits at a depth of about 35 feet based on a soil boring performed at 12 Beacon Bay.
Earth Materials
The site is underlain at depth by bedrock of the Monterey Formation based on regional geologic
maps. The bedrock is overlain by Marine deposits (Qm) and Artificial Fill (Af). Subsurface soils
encountered in our borings generally consisted of sands, silts and clays to the maximum depth
explored of 14.5 feet. The upper soils are primarily beach sands. These upper soils are
predominantly granular sands that are non-plastic and non-expansive. A layer of plastic silt and clay was encountered at a depth of about 4.8 feet. The moisture content of these materials
ranged from 30.7 to 45.9 percent in the samples collected. The marine deposits below the silt
and clay layers were medium dense and generally wet. Dense sands were encountered at a
depth of 13 feet.
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Geologic Hazard
The potential geologic hazards at the site are primarily from liquefaction, flooding and shaking
due to movement of nearby or distant faults during earthquake events. These are discussed in
greater detail below.
Portion of: PRELIMINARY DIGITAL GEOLOGICAL MAP OF THE 30’ X 60’ SANTA ANA QUADRANGLE, SOUTHERN CALIFORNIA, VERSION 2 U. S. Geological Survey, Open File Report 99-172 Compiled by D. M. Morton Groundwater
Groundwater was encountered at depths of about 5.5 to 6.5 feet in the exploratory borings.
On-site groundwater conditions may additionally be affected by tidal conditions and fluctuate
daily in conjunction with the ingoing and outgoing tides.
Water Infiltration
From a geotechnical standpoint, on-site water infiltration is allowable. A minimum setback of 3 feet from the nearest foundation is recommended for large volume runoff. Simple trench drains
and permeable pavement surfaces may be allowable without setback with appropriate agency
and geotechnical review and approvals. Proposed water infiltration features should be reviewed
and approved by the Geotechnical Consultant.
SITE
•~F---;---------~-
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Surficial Run-off
Proposed development should incorporate engineering and landscape drainage designed to
transmit surface and subsurface flow to the street and/or storm drain system via non-erosive
pathways.
Faulting/Seismic Considerations
The major concern relating to geologic faults is ground shaking that affects many properties
over a wide area. Direct hazards from faulting are essentially due to surface rupture along fault
lines that could occur during an earthquake. Therefore, geologists have mapped fault locations
and established criteria for determining the risks of potential surface rupture based on the
likelihood of renewed movement on faults that could be located under a site.
Based on criteria established by the California Division of Mines and Geology (CDMG), now
referred to as the California Geological Survey (CGS), faults are generally categorized as active,
potentially active or inactive (Jennings, 1994). The basic principle of faulting concern is that
existing faults could move again, and that faults which have moved more recently are the most
likely faults to move again and affect us. As such, faults have been divided into categories based on their age of last movement. Although the likelihood of an earthquake or movement to
occur on a given fault significantly decreases with inactivity over geologic time, the potential for
such events to occur on any fault cannot be eliminated within the current level of understanding.
By definition, faults with no evidence of surface displacement within the last 1.6 million years
are considered inactive and generally pose no concern for earthquakes due renewed movement. Potentially-active faults are those with the surface displacement within the last 1.6
million years. Further refinement of potentially active faults are sometimes described based on
the age of the last known movement such as late Quaternary (last 700,000 years) implying a
greater potential for renewed movement. In fact, most potentially active faults have little
likelihood of moving within the time frame of construction life, but the degree of understanding
of fault age and activity is sometimes not well understood due to absence of geologic data or
surface information, so geologists have acknowledged this doubt by using the term "potentially active." A few faults that were once thought to be potentially active, have later been found to
be active based on new findings and mapping. Active faults are those with a surface
displacement within the last 11,000 years and, therefore, most likely to move again. The State
of California has, additionally, mapped known areas of active faulting as designated Alquist-
Priolo (A-P) "Special Studies Zones,” which requires special investigations for fault rupture to
limit construction over active faults.
Based on our review of various published and unpublished reports, maps and documents, the site
is located approximately 1.5 to 3 kilometers northeast of the Newport-Inglewood Fault Zone. This fault consists of a series of parallel and en echelon, northwest-trending faults and folds extending
from the southern edge of the Santa Monica Mountains to Huntington Beach and then offshore
along Newport Beach. This fault zone has historically experienced moderate to high seismic
activity. No active or potentially active faults are known to project through the site. In addition, the Newport-Inglewood Fault is not sufficiently well-defined in the area of the subject site to be placed
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within the boundaries of an “earthquake fault zone,” as defined by the State of California in the Alquist-Priolo Earthquake Fault Zoning Act.
A potential seismic source near the site is the San Joaquin Hills Blind Thrust Fault (SJHBT), which
is approximately 2 to 8 kilometers beneath the site at its closest point, based on the reported fault
structure. The SJHBT is a postulated fault that is suspected to be responsible for uplift of the San
Joaquin Hills. This fault is a blind thrust fault that does not intercept the ground surface and,
therefore, presents no known potential for ground rupture at the property.
The potential for surface rupture at the site is considered to be low and the property is not
located within a special study zone for fault rupture. The site will experience shaking during
earthquake events on nearby or distant faults. Site improvements should take into consideration
the seismic design parameters outlined herein.
Site Classification for Seismic Design
Seismic design parameters are provided in a later section of this report and in Appendix F for
use by the Structural Engineer. The soil underlying the subject site has been classified in
accordance with Chapter 21 of ASCE 7, per Section 1613 of the 2019 CBC.
The results of our on-site field investigation, as well as nearby investigations by us and others,
indicate that the site is underlain by Class D medium dense to dense Marine sand deposits.
Based on the on-site test results and the proposed compacted fill soil, we recommend using a
characterization of this property as a Class D (Default), “Stiff Soil,” Site Classification.
SITE
Fault Map
Newport Beach, California
EXPLANATION
Fault: ~olid where location known, long da~hed
where approximate, dotted where inferred.
'-.\.. ~r:!:~':1:~::: e~,~~~e!Y !~~~::i~e
._ b.:i:;ed on geologic.JI ~11.ldie~.
Southwa.rd projection of active f.iuh traces ba~ed
on .J sub:.u1face ~tJJdy on lhe we~t bank of the
SJntliAnJ River.
''\. Se<:ond.uy fault tr.1.ces that hJve been ~hown
....,_ • .• to h.Jve moved Jt lel!t once during the Holocene.
1\. f.Julcth.uarenotJ.ctive.
D ~:~~:~a;~~~;g~";:~~z:;_ro, ~al-estate
-•.,. Newport Beach City Boundary
--.._ Sphereoflntluence
Scale: 1 :60,000
1.5 --==--=-MIies 3
.. , OS
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Secondary Seismic Hazards
Review of the Seismic Hazard Zones Map (CDMG, 1998) for the Newport Beach Quadrangle,
1997/1998 and the City of Newport Beach Seismic Safety Element (2008) indicates the site is
located within a zone of required investigation for earthquake-induced liquefaction.
Liquefaction Considerations
The area along Newport Harbor and its channels is in a Zone of Required Investigation for
liquefaction on the State of California Seismic Hazard Zones Map, Newport Beach Quadrangle.
Requirements for investigation are included in several documents including the City of Newport
Beach Building Code Policy (Revised 7/3/2014), the CBC Section 1803.5, and the Guidelines for
Evaluating and Mitigating Seismic Hazards in California, Special Publication 117A.
Liquefaction is a phenomenon in which the strength of a soil is reduced by earthquake shaking or
other rapid loading. Liquefaction occurs in saturated soils, that is, soils in which the void space between individual sand particles is completely filled with water. This water exerts a pressure on
the soil particles that influences how tightly the particles themselves are pressed together. Prior
to an earthquake, the water pressure is relatively low. However, earthquake shaking can cause
the water pressure to increase to the point where the soil particles can readily move with respect
to each other. Liquefaction generally occurs in sandy, granular soils.
When liquefaction occurs, the strength of the soil decreases and, the ability of a soil deposit to support foundations for buildings is reduced. The factors known to promote liquefaction potential
include high groundwater level, degree of saturation, relative density, grain size, soil type, depth
below the surface, and the magnitude and distance to the causative fault or seismic source. The
SITE
STATE Of CAUFOONIA
SEISMIC HAZARD ZONES
NEWPORT BEACH QUADRANGLE
OFFICIAL MAP
Liquefaction Zone Released: April 17, 1997
Landslide Zone Released: April 15, 1998
~
, ..
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subject site is in an area with potential for liquefaction (Morton and others, 1976; Toppozada and others, 1988).
In order to address liquefaction potential, soil borings were drilled to a maximum depth of 14.5
feet below the site. The deeper boring included SPT testing at intervals of 2 feet. In addition,
liquefaction analyses were performed to evaluate seismically-induced settlement. The results of
our analysis are included in Appendix E.
Based on the results of our analysis, some of the soil layers below the site, in the locations
tested, below the water table and to depths of at least 10 feet, have safety factors of less than
1.0, indicating risk of liquefaction during a seismic event strong enough to induce liquefaction.
Layers exhibiting safety factors of 1.3 and less based on Boulanger and Idriss (2010-16) were
evaluated for potential seismic settlement. Seismically-induced settlements were estimated by the
procedures developed by Boulanger and Idriss (2010-16) and Tokimatsu and Seed (1987).
Additionally, seismically-induced settlements were estimated by the procedures developed by Pradel (1998) for dry sand. The GeoAdvanced GeoSuite Software Version 2.4.2.21, developed by
Fred Yi, was utilized for the analyses (Appendix E). The resultant potential total seismic
settlement in the underlying soil was computed to be 0.83-inch within the upper 10 feet in Boring
B-1. It is our opinion that this settlement potential may be mitigated by the foundation system for support of the proposed structure.
Lateral Impacts of Liquefaction
Lateral spread is a hazard that sometimes occurs when there is sloping ground and weak lateral
restraint for soil undergoing liquefaction. Spread of soil into the bay would primarily affect areas
outside of the development limits since these areas are partially submerged with tidal fluctuations. As such, the house foundations are not expected to be impacted by the potential for
seismically induced lateral spread due to the setback of the structure from the bay. The risk of
lateral spread is therefore considered to be low.
Flooding
Seismically-induced flooding normally includes flooding from inland waters, which is not likely, and tsunami run-up from tidal wave energy. No specific tsunami analysis has been undertaken in
this investigation. However, the “Evaluation of Tsunami Risk to Southern California Coastal Cities”
(EERI, 2003) provides discussion of the impacts of locally seismic and/or landslide generated
tsunamis. The typical maximum run-up heights were estimated from 1 to 2 meters in the Newport Beach area. Because of unknown bathymetry on wave field interactions and irregular
coastal configurations, actual maximum run-up heights could range from 2 to 4 meters, or more.
The City of Newport Beach, in their Seismic Safety Element, describe Newport Beach as
somewhat protected from most distantly generated tsunamis by the Channel Islands and Point
Arguello, except for those generated in the Aleutian Islands, those off the coast of Chile, and
possibly off the coast of Central America. The publication also states that there may generally be
adequate warning given within the time frames from such distant events. The warnings would
allow for public safety but would not necessarily protect property improvements.
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Street flooding, particularly due to storm tides may occur periodically in low lying coastal and harbor areas. No evidence of uncontrolled concentrated runoff onto or off the subject property
was observed or reported based on our investigation.
According to flood zone maps prepared by FEMA, the site is located within an “0.2 % Annual
Chance Flood Hazard, Zone X” per flood zone map number 06059C0382K effective 3/21/2019.
Further evaluation of flooding potential and surface drainage at the site is deferred to the civil
engineer.
Other Secondary Seismic Hazards
Other secondary seismic hazards to the site include deep rupture and shallow ground cracking.
With the absence of active faulting on-site, the potential for deep fault rupture is low. The
potential for shallow ground cracking to occur during an earthquake is a possibility at any site,
but does not pose a significant hazard to site development.
CONCLUSIONS
1. Proposed development is considered feasible from a geotechnical viewpoint provided the recommendations of this report are followed during design, construction, and
maintenance of the subject property. Proposed development should not adversely affect
adjacent properties, providing appropriate engineering design, construction methods
and care are utilized during construction.
2. The property is underlain by beach and marine deposits to the maximum depth explored
of 14.5 feet.
3. The subgrade materials at the foundation levels are generally not suitable in their
present condition for structural support; however, these materials may be removed and
replaced as compacted, cement-treated, engineered fill in order to reduce the potential
for static and seismic settlement to acceptable levels.
4. Densification of the on-site soil may generally be accomplished through conventional grading methods by removal and recompaction of the soil.
5. Seismically-induced liquefaction has not historically been observed in the vicinity of the
site; however, the liquefaction of soils in the general area is considered to be a
possibility due to the presence of groundwater, underlying soil conditions and proximity
of nearby earthquake faults.
6. Our calculations indicate that potential settlement due to both liquefaction and
consolidation of dry sand layers caused by a large seismic event is less than 1-inch for
the upper zone that includes 10 feet below proposed foundations. Additional settlement
is also possible at greater depths. Foundation and slab design recommendations are
provided in consideration of the seismic settlement potential.
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7. Suitable drainage elements need to be installed within excavations and at retaining structures to mitigate possible transient seepage. Hydrostatic forces should be
accounted for when building below grade structures, such as swimming pools or
elevators, and adequate waterproofing should be provided in sensitive areas.
Groundwater conditions should be addressed in accordance with local ordinances and
practices, as well as agency requirements.
8. Ground water was encountered at a depth of 5.5 and 6.5 feet in the borings. Ground water levels are expected to be fairly static and not particularly affected by most tidal
fluctuations. Groundwater conditions should be addressed in accordance with local
ordinances and practices, as well as agency requirements. Hydrostatic forces should,
therefore, be accounted for in the foundation and slab design, and adequate
waterproofing should be provided in sensitive areas.
9. The near surface materials that were encountered were determined to have a very low expansion potential.
10. Grading and construction methods will need to consider lateral and subjacent support of
adjacent structures and property improvements.
11. Care must be taken during construction to not disturb the adjoining properties and
street improvements. An appropriate monitoring program is recommended during construction.
12. Although the probability of fault rupture across the property is low, ground shaking may
be strong during a major earthquake.
13. Tsunami potential for this site is considered moderate; although historically such effects
have been subdued in southern California due to topographic protection from distant
seismic events and the rarity of significant offshore earthquakes.
14. Adverse surface discharge onto or off the site is not anticipated provided proper civil
engineering design and post-construction site grading are implemented.
15. The proposed structure should be supported by a mat slab and foundation system
resting entirely within recompacted fill materials.
16. The recommendations herein should be confirmed at the time of the excavation cuts
during grading to verify the preliminary findings contained herein.
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RECOMMENDATIONS
Site Preparation and Grading
1. General
Site grading should be performed in accordance with the requirements of the City of
Newport Beach, the recommendations of this report, and the Standard Grading
Guidelines of Appendix D. All excavations should be supervised and approved in writing
by a representative of this firm.
2. Demolition and Clearing
Deleterious materials, including those from the demolition of the existing concrete,
vegetation, organic matter and trash, should be removed and disposed of off-site.
Subsurface elements of demolished structures should be completely removed, including
any trench backfills, abandoned foundations, cisterns, utility lines, etc.
3. Subgrade Preparation
The site preparation and fill placement should include the following components:
1. Excavation of the on-site materials to a depth of 3 feet within the structural
footprint of the new house.
2. Scarification and compaction of the removal bottom to a depth of 6 to 8-inches.
3. Stabilization of the exposed, scarified bottom materials by mixing with cement.
4. Placement of on-site and/or imported cement-treated fill to design grades.
Excavations should be made to remove any soils disturbed by demolition,
undocumented fill and surficial materials where encountered within the planned building
areas. Earth removals are recommended to allow densification of the sand deposits and to provide uniform bearing conditions within the upper materials below foundation and
slab areas. Removals should be followed by 6 to 8-inches of scarification and
recompaction. These remedial excavations should be made within the planned building
footprint. Deeper excavations may be necessary to remove unsuitable materials, if encountered. Grading activities must be carried out in a manner that does not remove
lateral support or undermine the existing property line walls. We, therefore, recommend
that depths of any existing wall footings be verified when exposed following demolition
and prior to the start of grading. Although not expected to be necessary, lateral support
may sometimes be achieved by the use of bracing, slot cutting, or trenching where wall
footings are shallow relative to excavation depths.
Excavations during grading should be replaced with compacted, cement-treated
engineered fill. The horizontal limits of overexcavation should be outlined by the
geotechnical engineer based on grading and foundation plans when these are available
for review.
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Removals below significant hardscape improvements such as driveways, patios, and sidewalks should be sufficient to remove existing disturbed or loose surface soil.
Removal depths of 12 to 24-inches are expected to be adequate in exterior areas;
however boundary conditions for removals under exterior improvements may be better
addressed subsequent to demolition when equipment can expose the site materials for
evaluation and when improvement limits are identified on the plan.
Dewatering is not expected to be necessary at planned removal depths.
The depths of overexcavation should be reviewed by the Geotechnical Engineer or
Geologist during the actual construction. Any surface or subsurface obstructions, or
questionable material encountered during grading, should be brought immediately to the
attention of the Geotechnical Engineer for recommendations.
4. Fill Soils
The on-site soils are anticipated to be suitable for use as compacted fill; however,
cement treatment using Portland Cement is recommended within the graded building
pad to provide additional soil strength, aid in the foundation construction and reduce collapse potential of vertical footing cuts. Fill soils should be free of debris, organic
matter, cobbles and concrete fragments greater than 6-inches in diameter.
Soils imported to the site for use as fill below foundation and slab areas should be
predominantly granular, non-expansive, non-plastic and approved by the Geotechnical
Engineer prior to importing.
5. Shrinkage
Shrinkage losses are expected to be about 3 percent overall. This does not include
clearing losses from demolition that could result in volume reductions for available fill
soils.
6. Expansive Soils
Expansion tests should be performed during grading to determine the expansion
potential of the processed fill materials. On-site surface soils encountered during our
investigation were determined to be non-plastic, non-expansive sands.
7. Compaction Standard
The on-site soils are anticipated to be generally suitable for use as compacted fill. Highly
organic and oversize materials must be removed prior to compaction. Fill materials
should be placed at above optimum moisture content and compacted under the
observation and testing of the Soil Engineer. The recommended minimum density for compacted material is 90 percent of the maximum density as determined by ASTM
D1557-12.
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8. Temporary Construction Slopes
Temporary slopes exposing on-site materials should be cut in accordance with Cal/OSHA
Regulations. It is anticipated that the exposed on-site earth materials may be classified
as Type C soil, and temporary cuts of 1:1 (horizontal: vertical) or flatter may be
appropriate to heights of 5-feet or less; however, the material exposed in temporary
excavations should be evaluated by the Contractor during construction. Dry or running
sands may require flatter laybacks. Temporary construction slopes should not be left exposed overnight unless approved in writing by the Geotechnical Consultant. The
cement-treated fill soils may be cut vertical to a maximum height of 3 feet.
Excavations should proceed in a manner so as not to remove lateral or bearing support
of adjacent properties or structures. Along property lines, cuts of 1:1 or flatter are
typically prudent and are required by the City of Newport Beach. Care will be needed
along the property lines. The soils exposed in the excavation cuts should be observed by the Geotechnical Consultant during excavation.
The safety and stability of temporary construction slopes and cuts is deferred to the
General Contractor, who should implement the safety practices as defined in Section 1541, Subchapter 4, of Cal/OSHA T8 Regulations (2006). The Geotechnical Consultant
makes no warranties as to the stability of temporary cuts. Soil conditions may vary
locally and the Contractor(s) should be prepared to remedy local instability if necessary. Contract documents should be written in a manner that places the Contractor in the
position of responsibility for the stability of all temporary excavations. Stability of
excavations is also time dependent.
If unsupported property line cuts are made, the Contractor should monitor the
performance of adjacent structures and improvements during construction. If movement
or distress is noted, appropriate remedial measures should be immediately implemented.
9. Adjacent Property Assessments and Monitoring
The following measures may be considered in order to reduce the potential risks of damage, and perceived damage, to adjoining improvements:
• Visual inspections and walk-throughs of each of the adjacent properties should
be arranged in order to document pre-existing conditions and damages.
• Measurements of all existing damages observed, including crack lengths, widths
and precise locations should be made.
• Photographs should be taken to accompany written notes that refer to damages or even lack of damages. Video may also be considered; however, videos that
attempt to show these types of damages are often lacking in detail.
• Floor level surveys of nearby structures may be considered especially if pre-existing damage is evident.
• Vibrations from construction equipment may be monitored with portable
seismographs during excavation.
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• Surveys to monitor lateral and vertical position of adjacent improvements and shoring elements is recommended.
• It is recommended that the Project Geologist be on-site during excavation in
order to evaluate conditions as the project advances.
Construction activities, particularly excavation equipment, produce vibrations that can be
felt by occupants of adjoining properties. People will often be annoyed by the noise and
vibration caused by construction activities, which prompts them to personally perform
detailed inspections of their property for damage. Pre-existing damage, that previously
went unnoticed, can be unfairly attributed to current construction activities, particularly
when pre-construction property inspections are not performed. At that point, it may be difficult to determine what caused the damage, especially damages such as wall
separations, cracks in drywall, stucco and masonry. Other common problems that may
be scrutinized can include uneven doors, sticking windows, tile cracks, leaning patio
posts, fences, gates, etc. Implementation of measures such as those listed above can
help avoid conflicts by monitoring construction activities that may be problematic as well
as provide valuable data to defend against unwarranted claims.
Foundation Design
1. General
It is anticipated that foundation elements for the planned structure will bear in re-
compacted fill and will utilize a mat slab foundation.
The near surface materials are expected to exhibit a very low expansion potential. The
following recommendations are based on the geotechnical data available and are subject
to revision based on conditions actually encountered in the field.
Foundations and slabs should be designed for the intended use and loading by the
structural engineer. Our recommendations are considered to be generally consistent
with the standards of practice. They are based on both analytical methods and empirical
methods derived from experience with similar geotechnical conditions. These recommendations are considered the minimum necessary for the likely soil conditions
and are not intended to supersede the design of the Structural Engineer or criteria of
governing agencies.
2. Bearing Capacity for Foundations
A mat slab may be utilized to support the proposed structure. The purpose of the mat slab system is to help mitigate potential earthquake effects, static and seismic
settlement and to provide an appropriate foundation in the local marine environment.
The allowable bearing capacity for a mat slab type system founded in re-compacted fill
should not exceed 1,500 pounds per square foot. This value may be increased by one-third for short-term wind or seismic loading; however, there is no increase in bearing
value with depth. A minimum slab thickness of 12-inches is recommended. For design of
a mat foundation system, a modulus of subgrade reaction of 100 pounds per cubic inch
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R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
may be considered (172 kips per cubic foot). The subgrade is expected to consist of sand. Actual thickness, depths and widths of the foundation and slab system should be
governed by CBC requirements and the structural engineering design.
3. Settlement
Static
Static settlement is anticipated to be on the order of 1-inch total and 0.5-inch differential
between adjacent similarly loaded columns (approximately 30 feet assumed horizontal
distance), provided that the recommended site grading is implemented first and that the
bearing capacity values given above are not exceeded. These estimates should be
confirmed when structural engineering plans are prepared and foundation load
conditions are determined.
Dynamic
Potential seismic dry sand and liquefaction-induced settlement based on current
estimates of peak ground accelerations during an earthquake was calculated to be 0.83-inch total within the upper 14.5 feet (see Appendix E). Additional seismic settlement is
not expected below that depth. The underlying stratigraphy is fairly uniform below the
planned development area; therefore, differential seismic settlement can be estimated
as approximately one-half of the total estimated settlement, or on the order of 0.5-inch
across a span of about 30 feet (Martin and Lew, 1999). Seismically-induced settlements
were estimated by using the procedure of Boulanger and Idriss (2010-16) and
Tokimatsu and Seed (1987). These methods are based on empirical data from past seismic events that have been studied and are, therefore, approximate.
4. Lateral Resistance
Lateral loads may be resisted by passive pressure forces developed in front of the
slab/foundation system and by friction acting at the base of the mat slab. Allowable
lateral resistance should not exceed 150 pounds per square foot per foot of depth equivalent fluid pressure. Resistance to sliding can be calculated using a coefficient of
friction of 0.25. These values may be used in combination per 2019 CBC, Section
1806.3.1.
5. Footing Reinforcement
Two No. 5 bars should be placed at the top and two at the bottom of continuous
footings in order to resist potential movement due to various factors such as subsurface
imperfections and seismic shaking. Dowelled connections between the slab and footings
should be provided and should consist of No. 4 bars at 24-inches on center maximum
spacing. Quantity and placement of reinforcing steel should be determined by the structural engineer.
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R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
Seismic Design
Based on the geotechnical data and site parameters, the following table is provided based on
ASCE/SEI 7-16 using the ASCE Hazard Tool to satisfy the 2019 CBC design criteria. A site-
specific Ground-Motion Hazard Analysis (GMHA) was not performed for the site.
Site and Seismic Design Criteria
For 2019 CBC
Design
Parameters Recommended
Values
Site Class D (Default)*
(Stiff Soil)
Site Longitude (degrees) -117.898883 W
Site Latitude (degrees) 33.61006 N
Ss (g) 1.384 g
S1 (g) 0.492 g
SMs (g) 1.661 g
SM1 (g) 0.890 g
SDs (g) 1.107 g
SD1 (g) 0.593 g
Fa 1.2
Fv 1.808
Seismic Design Category D
*Per ASCE 7-16, Section 11.4.8, the above values may be used provided the value of the seismic
response coefficient Cs is determined by Eq. (12.8-2) for values of T ≤ 1.5Ts and taken as equal to 1.5
times the value computed in accordance with either Eq. (12.8-3) for TL ≥ T > 1.5Ts or Eq. (12.8-4) for T > TL. This is due to the value of S1 greater than or equal to 0.2 g for this site. The values above are generally applicable for typical residential structures. The Structural Engineer should verify that Section
11.4.8 is satisfied per the above.
A Site-Specific Ground Motion Hazard Analysis (GMHA) may be beneficial for this project as part of the
structural design. A Site-Specific GMHA can be performed at an additional cost if requested.
Supporting documentation is also included in a previous section of this report, Site Classification
for Seismic Design, and in Appendix F.
I I I
I I I
I I I
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R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
Slab-On-Grade Construction
Slabs should be designed in accordance with the 2019 CBC and the requirements of the City of
Newport Beach. On-site materials were determined to be non-plastic. Concrete floor slabs
should be at least 12-inches thick (actual). Slab design and reinforcement should be determined
by the Structural Engineer; however, the minimum slab reinforcement should consist of No. 4 bars at 12-inches on-center in each direction placed at the top and bottom of the slab (or
approved equivalent). These recommendations assume that the subsurface soils have first been
densified as recommended above.
Slabs should be underlain by 4-inches of open-graded gravel. Slab underlayment is deferred to
the Project Architect; however, in accordance with the American Concrete Institute, we suggest
that slabs be underlain by a 15-mil thick vapor retarder/barrier (Stego Wrap or equivalent)
placed over a layer of woven geofabric (such as Mirafi 140N) over the gravel in accordance with
the requirements of ASTM E1745 and E1643. Slab subgrade soils should be well moistened prior
to placement of the vapor retarder. All subgrade materials should be geotechnically approved
prior to placing the gravel for the slab underlayment. The above recommendations are provided
for vapor transmission considerations but do not provide for waterproofing of the slab in the
local marine environment. If flooding is a concern, additional underlayment measures may be
appropriate and should be addressed by the Civil Engineer and/or Project Architect.
Exterior flatwork elements should be a minimum 4-inches thick (actual) and reinforced with No.
3 bars 18-inches on center both ways. Subgrade soils should be well moistened prior to placing
concrete.
Structural Design of Retaining Walls
1. Lateral Loads
Active pressure forces acting on backfilled retaining walls which support level ground
may be computed based on an equivalent fluid pressure of 35 pounds per cubic foot.
Restrained retaining walls should add an additional 6H pounds per cubic foot for at-rest
loading, where H is the retained height of the soil.
Other topographic and structural surcharges should be addressed by the Structural
Engineer. Minor wall rotations should be anticipated for walls that are free to rotate at
the top and considered in design of walls and adjacent improvements.
2. Earthquake Loads on Retaining Walls
The Structural Engineer should determine if there are retaining walls at the site within
their purview that will be subject to design lateral loads due to earthquake events.
Section 1803.5.12 of the 2019 CBC states that the geotechnical investigation shall
include the determination of dynamic seismic lateral earth pressures on foundation walls and retaining walls supporting more than 6 feet (1.83 m) of backfill height due to design
earthquake ground motions. No walls are currently planned to heights that include 6
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R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
feet of retained backfill and, therefore, the site development is not subject to the design requirements of Section 1803.5.12.
3. Foundation Bearing Values for Walls
Footings for retaining walls may be designed in accordance with the recommendations
provided above for building foundations and should be embedded in compacted fill at a
minimum depth of 15-inches below the lowest adjacent grade.
4. Wall Backfill
The on-site soils are suitable for use as retaining wall backfill. Imported backfill, if
needed, should consist of select, non-expansive soil or gravel. Gravel may consist of pea
gravel or crushed rock. Where space for compaction equipment is adequate, on-site or
imported granular, non-expansive sand materials may be compacted into place in thin
lifts per the compaction requirements provided herein. Imported pea gravel or crushed
rock should be placed in lifts and tamped or vibrated into place. The lift thickness for
gravel is dependent on the type of material and method of compaction. Gravel lifts of
18- to 24-inches or less are recommended. The Geotechnical Engineer should observe the backfill placement of soil or gravel behind each wall following approval of wall
backdrains. Gravel wall backfill material should be covered with a suitable filter fabric
such as Mirafi 140N and capped with on-site soil or concrete.
Fill soils should be free of debris, organic matter, cobbles and rock fragments greater
than 6-inches in diameter. Fill materials should be placed in 6- to 8-inch maximum lifts
at above optimum moisture content and compacted under the observation and testing of the Soil Engineer. The recommended minimum density for compacted material is 90
percent of the maximum dry density as determined by ASTM D1557-12. Field density
tests should be performed at intervals of 2 vertical feet or less within the backfill zone
and in accordance with agency requirements at the time of grading.
5. Subdrains
An approved exterior foundation subdrain system should be used to achieve control of
seepage forces behind retaining walls. The details of such subdrain systems are deferred
to the Wall Designer, Builder or Waterproofing Consultant. The subdrain is not a
substitute for waterproofing. Water in subdrain systems should be collected and delivered to suitable disposal locations or facilities. Additional recommendations may be
provided when plans are available. Walls retaining less than 2.5 feet of soil may not
require a subdrain if alternate drainage relief is provided.
6. Dampproofing and Waterproofing
Waterproofing in consideration of the local marine environment should be installed in accordance with the architectural specifications or those of a Waterproofing Consultant.
The criteria in Section 1805 of the 2019 CBC should be followed as a minimum.
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R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
Hardscape Design and Construction
Hardscape improvements may utilize conventional foundations in compacted fill. Such
improvements should be designed in accordance with the foundation recommendations
presented above. Cracking and offsets at joints are possible; however, occurrence may be
minimized by appropriate drainage and the use of thickened edge beams to limit moisture transfer below slabs.
Concrete flatwork should be divided into as nearly square panels as possible. Joints should be
provided at maximum 8-feet intervals to give articulation to the concrete panels (shorter
spacing is recommended if needed to square the panels).
Landscaping and planters adjacent to concrete flatwork should be designed in such a manner as
to direct drainage away from concrete areas to approved outlets. Planters located adjacent to
principle foundation elements should be sealed and drained; this is especially important if they
are near retaining wall backfills.
Exterior flatwork elements should be a minimum 4-inches thick (actual) and reinforced with No.
3 bars 18-inches on center both ways. Subgrade soils should be well moistened prior to placing
concrete.
Concrete Construction Components in Contact with Soil
Testing of the on-site sandy soils resulted in a low soluble sulfate content. Various components
within the concrete may be subject to corrosion over time when exposed to soluble sulfates and
chemical attack. To help mitigate corrosion, sulfate resistant cement should be used in concrete that may be in contact with on-site soils or ground source water. Attention to maximum water-
cement ratio and the minimum compressive strength may also help mitigate deterioration of
concrete components. The sulfate testing is presented in the attached Appendix C, Laboratory
Test Results.
Type V cement or an appropriate alternate is, therefore, recommended with a maximum water-
cement ratio of 0.5 percent. The minimum concrete compressive strength should be at least 4,000 pounds per square inch.
It is recommended that a concrete expert be retained to design an appropriate concrete mix to
address the structural requirements. In lieu of retaining a concrete expert, it is recommended
that the 2019 CBC, Section 1904 and 1905, be utilized which refers to ACI 318. Testing should
be performed during grading when fill materials are identified to confirm the sulfate
concentration.
Metal Construction Components in Contact with Soil
Metal rebar encased in concrete, iron pipes, copper pipes, lift shafts, air conditioner units, etc., that are in contact with soil or water that permeates the soil should be protected from corrosion
that may result from salts contained in the soil. Recommendations to mitigate damage due to
corrosive soils, if needed, should be provided by a qualified corrosion specialist.
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R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
Finished Grade and Surface Drainage
Finished grades should be designed and constructed so that no water ponds in the vicinity of
footings. Drainage design in accordance with the 2019 CBC, Section 1804.4, is recommended or
per local City requirements. Roof gutters should be provided and outflow directed away from
the house in a non-erosive manner as specified by the Project Civil Engineer or Landscape
Architect. Surface and subsurface water should be directed away from building areas. Proper interception and disposal of on-site surface discharge is presumed to be a matter of civil
engineering or landscape architectural design.
Foundation Plan Review
The undersigned should review final foundation plans and specifications prior to their
submission to the building official for issuance of permits. The review is to be performed only
for the limited purpose of checking for conformance with design concepts and the information
provided herein. Review shall not include evaluation of the accuracy or completeness of details,
such as quantities, dimensions, weights or gauges, fabrication processes, construction means or
methods, coordination of the work with other trades or construction safety precautions, all of
which are the sole responsibility of the Contractor. R McCarthy Consulting’s review shall be
conducted with reasonable promptness while allowing sufficient time in our judgment to permit
adequate review. Review of a specific item shall not indicate that R McCarthy Consulting has
reviewed the entire system of which the item is a component. R McCarthy Consulting shall not
be responsible for any deviation from the Construction Documents not brought to our attention in writing by the Contractor. R McCarthy Consulting shall not be required to review partial
submissions or those for which submissions of correlated items have not been received.
Utility Trench Backfill
Utility trench backfill should be placed in accordance with Appendix D, Standard Earthwork
Guidelines. It is the Owner’s and Contractor’s responsibility to inform Subcontractors of these
requirements and to notify R McCarthy Consulting when backfill placement is to begin. It has
been our experience that trench backfill requirements are rigorously enforced by the City of Newport Beach.
The on-site soils are anticipated to be generally suitable for use as trench backfill; however, silt
materials may be difficult to mix and compact to a uniform condition. The use of imported
backfill is sometimes more efficient when silt soil materials are at high moisture contents. Fill
materials should be placed at near optimum moisture content and compacted under the
observation and testing of the Soil Engineer. The minimum dry density required for compacted backfill material is 90 percent of the maximum dry density as determined by ASTM D1557-12.
Pre-Grade Meeting
A pre-job conference should be held with representative of the Owner, Contractor, Architect,
Civil Engineer, Geotechnical Engineer, and Building Official prior to commencement of
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R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
construction to clarify any questions relating to the intent of these recommendations or additional recommendations.
OBSERVATION AND TESTING
General
Geotechnical observation and testing during construction is required to verify proper removal of unsuitable materials, check that foundation excavations are clean and founded in competent
material, to test for proper moisture content and proper degree of compaction of fill, to test and
observe placement of wall and trench backfill materials, and to confirm design assumptions. It
is noted that the CBC requires continuous verification and testing during placement of fill, pile
driving, and pier/caisson drilling.
An R McCarthy Consulting representative shall observe the site at intervals appropriate to the
phase of construction, as notified by the Contractor, in order to observe the work completed by
the Contractor. Such visits and observation are not intended to be an exhaustive check or a
detailed inspection of the Contractor’s work but rather are to allow R McCarthy Consulting, as
an experienced professional, to become generally familiar with the work in progress and to determine, in general, if the grading and construction is in accordance with the
recommendations of this report.
R McCarthy Consulting shall not supervise, direct, or control the Contractor’s work. R McCarthy
Consulting shall have no responsibility for the construction means, methods, techniques,
sequences, or procedures selected by the Contractor, the Contractor’s safety precautions or
programs in connection with the work. These rights and responsibilities are solely those of the
Contractor.
R McCarthy Consulting shall not be responsible for any acts or omission of any entity
performing any portion of the work, including the Contractor, Subcontractor, or any agents or
employees of any of them. R McCarthy Consulting does not guarantee the performance of any
other parties on the project site, including the Contractor, and shall not be responsible for the
Contractor’s failure to perform its work in accordance with the Contractor documents or any applicable law, codes, rules or regulations.
Construction phase observations are beyond the scope of this investigation and budget and are
conducted on a time and material basis. The responsibility for timely notification of the start of
construction and ongoing geotechnically involved phases of construction is that of the Owner
and his Contractor. We request at least 48 hours’ notice when such services are required.
Geotechnical Observation/Testing Activities during Grading and Construction
The Geotechnical Consultant should be notified to observe and test the following activities
during grading and construction:
• To observe proper removal of unsuitable materials;
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R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
• To observe the bottom of removals for all excavations for the building pad grading, trenching, exterior site improvements, etc.;
• To observe side cut excavations for grading, retaining walls, trenches, etc.;
• To test for proper moisture content and proper degree of compaction of fill;
• To check that foundation excavations are clean and founded in competent material;
• To check the slab subgrade materials prior to placing the gravel, vapor barrier and
concrete;
• To check retaining wall subdrain installation;
• To test and observe placement of wall backfill materials;
• To test and observe placement of all trench backfill materials;
• To test and observe patio, driveway apron and sidewalk subgrade materials;
• To observe any other fills or backfills that may be constructed at the site.
It is noted that this list should be used as a guideline. Additional observations and testing may be
required per local agency, code, project, Contractor and geotechnical requirements at the time of
the actual construction.
LIMITATIONS
This investigation has been conducted in accordance with, and limited to, generally accepted
practice in the engineering geologic and soils engineering field, and in accordance with services
provided by geotechnical consultants practicing in the same or similar locality under the same
or similar circumstances. No further warranty, expressed or implied, is made as to the
conclusions and professional advice included in this report. Conclusions and recommendations
presented are based on subsurface conditions encountered and are not meant to imply that we have control over the natural site conditions. The samples taken and used for testing, the
observations made and the field testing performed are believed representative of the general
project area; however, soil and geologic conditions can vary significantly between tested or
observed locations.
Site geotechnical conditions may change with time due to natural processes or the works of
man on this or adjacent properties. In addition, changes in applicable or appropriate standards may occur as a result of the broadening of knowledge, new legislation, or agency requirements.
The recommendations presented herein are, therefore, arbitrarily set as valid for one year from
the report date. The recommendations are also specific to the current proposed development.
Changes in proposed land use or development may require supplemental investigation or recommendations. Also, independent use of this report without appropriate geotechnical
consultation is not approved or recommended.
PA2021-036
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R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
Thank you for this opportunity to be of service. If you have any questions, please contact this
office.
Respectfully submitted,
R MCCARTHY CONSULTING, INC.
Robert J. McCarthy
Principal Engineer, G.E. 2490
Registration Expires 3-31-22
Date Signed: 1/28/2021
Accompanying Illustrations and Appendices
Text Figure - Preliminary Geologic Map of the 30’ X 60’ Santa Ana Quadrangle
Text Figure - Fault Map, Newport Beach, California
Text Figure - CDMG Seismic Hazards Location Map Figure 1 - Geotechnical Plot Plan
Figure 2 - Location Map
Figure 3 - Geologic Hazard Map
Appendix A - References Appendix B - Field Exploration
Figures B-1 through B-3
Appendix C - Laboratory Testing
Figures C-1 through C-6
Appendix D - Standard Grading Guidelines
Appendix E - Results of Liquefaction Analysis
Appendix F - Seismicity Data
PA2021-036
BASIS OF BEARINGS THE BASIS OF BEARINGS SHOWN HEREON ARE BASED ON THE U.S. BULKHEADLINE HAVING A BEARING OF N90°00'00"E PER RS NO. 2015-1249, R.S.B. 296/22.
VICINITY MAP
BENCHMARK INFORMATION
TITLE REPORT/EASEMENT NOTES NO TITLE REPORT PROVIDEDLEGAL DESCRIPTIONREAL PROPERTY SITUATED IN THE CITY OF NEWPORT BEACH,COUNTY OF ORANGE, STATE OF CALIFORNIA AND ISDESCRIBED AS FOLLOWS:LOT 13 AS PER MAP RECORDED IN R.S.B. 9, PAGES 42-43, INTHE OFFICE OF THE COUNTY RECORDER OF SAID COUNTY.LC EXISTING ELEVATIONLEGEND( )AC ASPHALT PAVEMENTFOUND MONUMENT
SEARCHED, FOUND NOTHING; SETNOTHING
FS FINISHED SURFACEFFGFINISHED FLOOR GARAGE CONCRETE SURFACE
T.B.M.TEMPORARY BENCHMARKSET ON A WATER METER (WM)ELEVATION = 9.70 FEET
HUNTINGTON BEACH, CALIFORNIA 92646PHONE:(714)488-5006 FAX:(714)333-4440 APEXLSINC@GMAIL.COMPAUL D. CRAFT, P.L.S. 8516 DATE
NOTE: SECTION 8770.6 OF THE CALIFORNIA BUSINESS AND PROFESSIONS CODESTATES THAT THE USE OF THE WORD CERTIFY OR CERTIFICATION BY ALICENSED LAND SURVEYOR IN THE PRACTICE OF LAND SURVEYING OR THEPREPARATION OF MAPS, PLATS, REPORTS, DESCRIPTIONS OR OTHER SURVEYINGDOCUMENTS ONLY CONSTITUTES AN EXPRESSION OF PROFESSIONAL OPINIONREGARDING THOSE FACTS OR FINDINGS WHICH ARE THE SUBJECT OF THECERTIFICATION AND DOES NOT CONSTITUTE A WARRANTY OR GUARANTEE,EITHER EXPRESSED OR IMPLIED.
LICENSE RENEWAL DATE 12/31/20
PAULDOMINICK
C
RAFTPROFESSIO N AL LANDSU
R
V
EYORFF FINISHED FLOORWATER METERWMGAS METERGMCENTERLINEPAPLANTER AREA
GRAPHIC SCALE
SURVEYOR OR ENGINEER SHALL PERMANENTLY MONUMENT PROPERTYCORNERS OR OFFSETS BEFORE STARTING GRADING.
PLEASE CALL PAUL CRAFT @ 714-488-5006 TO SCHEDULE.
SURVEYOR'S NOTES
BLOCK WALL BRICK SURFACENGNATURAL GROUND BENCHMARK NO: NB4-39-77DESCRIBED BY OCS 2002 - FOUND 3 3\4" OCSALUMINUM BENCHMARK DISK STAMPED "NB4-39-77", SET IN THE NORTHEAST CORNER OF A 4.3 FT.BY 4.8 FT. CONCRETE CATCH BASIN. MONUMENT ISLOCATED IN THE SOUTHEAST CORNER OF THEINTERSECTION OF BAYSIDE DRIVE AND HARBORISLAND DRIVE, 64.6 FT. EASTERLY OF THECENTERLINE OF HARBOR ISLAND DRIVE AND 38 FT.SOUTHERLY OF THE CENTERLINE OF BAYSIDEDRIVE. MONUMENT IS SET LEVEL WITH THESIDEWALK.ELEVATION: 10.859 FEET (NAVD88), YEAR LEVELED 2011EPBELECTRICAL PULL BOXSCO SEWER CLEAN OUTSLSTREET LIGHTTFTOP OF FENCETPBTELEPHONE PULL BOXTWTOP OF WALLWATER
Figure 1: Geotechnical Plot Plan
13 Beacon Bay
Newport Beach, CA
File: 8527-00 January 2021
0 20 feetNHA-1
B-1
Base map: Apex Land Surveying, Inc.
EXPLANATION
Estimated location of exploratory boring
Af Articial ll
Qm Marine deposits
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(8.7ij)/ (9.6~\
(9.02) ~
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PA2021-036
Feet
Every reasonable effort has been made to assure the
accuracy of the data provided, however, The City of
Newport Beach and its employees and agents
disclaim any and all responsibility from or relating to
any results obtained in its use.
Disclaimer:
1/26/2021
0 400200
SITE:
13 Beacon Bay
FILE NO: 8527-00 JANUARY 2021 FIGURE 2 - LOCATION MAP
PA2021-036
Feet
Every reasonable effort has been made to assure the
accuracy of the data provided, however, The City of
Newport Beach and its employees and agents
disclaim any and all responsibility from or relating to
any results obtained in its use.
Disclaimer:
1/26/2021
0 400200
FIGURE 3 - GEOLOGIC HAZARDS MAPJANUARY 2021FILE NO: 8527-00
SITE:
13 Beacon Bay Liquefaction
Hazard Zone
PA2021-036
APPENDIX A
REFERENCES
PA2021-036
APPENDIX A REFERENCES
(13 Beacon Bay)
R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
1. Apex Surveying Inc., 2020, Topographic Map, 13 Beacon Bay, Newport Beach, CA
92660, Scale: 1” = 8’, Project No. 20125, October 23.
2. American Society of Civil Engineers (ASCE), 2019, ASCE 7 Hazard Tool,
https://asce7hazardtool.online/. 3. ASCE/SEI 7-16, "Minimum Design Loads and Associated Criteria for Buildings and Other
Structures"
4. Barrows, A. G., 1974, “A Review of the Geology and Earthquake History of the Newport-
Inglewood Structural Zone, Southern California,” California Division of Mines and
Geology, Special Report 114.
5. Brandon Architects, “Irwin Residence, 13 Beacon Bay, Newport Beach CA 92603”
undated
6. Building Seismic Safety Council, 2004, National Earthquake Hazards Reduction Program
(NEHRP) Recommended Provisions for Seismic Regulations for New Buildings and Other
Structures (FEMA 450), 2003 Edition, Part 2: Commentary, Washington, DC.
7. California Building Code, 2019 Edition. 8. California Division of Mines and Geology, 1998, “Seismic Hazards Zones Map, Newport
Beach Quadrangle”.
9. California Divisions of Mines and Geology, 2008, “Guidelines for Evaluating and
Mitigating Seismic Hazards in California,” Special Publication 117A.
10. City of Newport Beach, 2014, Community Development Department, Building Division,
Building Code Policy, “Liquefaction Study Mitigation Measures,” revised July 14.
11. Coast Geotechnical, 2016, “Geotechnical Engineering Investigation of Proposed New Residence at 20 Beacon Bay, Newport Beach, California,” W. O. 514716-01, July 29.
12. Coast Geotechnical, 2017, “Geotechnical Investigation of Proposed New Residence at 14
Beacon Bay, Newport Beach, California,” W. O. 524316-01, January 10.
13. Coast Geotechnical, 2018, “Geotechnical Investigation of Proposed New Residence at 16
Beacon Bay, Newport Beach, California,” W. O. 539317-01, October 30.
14. Department of the Navy, 1982, NAVFAC DM-7.1, Soil Mechanics, Design Manual 7.1,
Naval Facilities Engineering Command.
15. EGA Consultants, 2014, “Geotechnical Investigation for Proposed Residential
Development Located at 18 Beacon Bay, Newport Beach, California,” Project No.
EO836.1, October 31.
16. Geofirm, 2002, “Geotechnical Investigation for Foundation Design, Proposed Single
Family Residence, 12 Beacon Bay, Newport Beach, California,” Project No. 71321-00,
Report No. 02-4069, October 18.
17. Hart, E. W., and Bryant, W. A., 1997, “Fault-Rupture Hazard Zones in California, Alquist-
Priolo Earthquake Fault Zoning Act: California Division of Mines and Geology,” Special
Publication 42 (Interim Supplements and Revisions 1999, 2003, and 2007).
18. Jennings, Charles W., et al., 1994, “Fault Activity Map of California and Adjacent Areas,”
California Division of Mines and Geology, Geologic Data Map No. 6. 19. Martin, G. R. and Lew, M., 1999, “Recommended Procedures for Implementation of
DMG Special Publication 117, Guidelines for Analyzing and Mitigating Liquefaction
Hazards in California,” Southern California Earthquake Center (SCEC), University of
Southern California, 63 pages, March.
20. Morton and Miller, 1981, Geologic Map of Orange County, CDMG Bulletin 204.
PA2021-036
APPENDIX A REFERENCES
(13 Beacon Bay)
R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
21. Morton, P. K., Miller, R. V., and Evans, J. R., 1976, “Environmental Geology of Orange
County, California: California Division of Mines and Geology,” Open File Report 79-8 LA.
22. Morton, D. M., Bovard, Kelly H., and Alvarez, Rachel M., 2004, “Preliminary Digital
Geological Map of the 30’ X 60’ Santa Ana Quadrangle, Southern California,” Version 2.0,
Open-File Report 99-172, Version 2.0 – 2004. 23. Morton, Douglas M., and Miller, Fred K., Compilers, 2006, “Geologic Map of the San
Bernardino and Santa Ana 30’ X 60’ Quadrangles, California,” U. S. Geological Survey
Open File Report 2006-1217.
24. Petersen, M. D., Bryant, W. A., Cramer, C. H., Cao, T., Reichle, M. S., Frankel, A. D.,
Lienkaemper, J. J., McCrory, P. A., and Schwartz, D. P., 1996, “Probabilistic Seismic
Hazard Assessment for the State of California,” Department of Conservation, Division of
Mines and Geology, DMG Open-File Report 96-08, USGS Open File Report 96-706.
25. Schmertmann, Dr. John H., 1977, “Guidelines for CPT Performance and Design,”
Prepared for the Federal Highway Administration, U. S. Department of Transportation,
FHWA-TS-78-209, February.
26. Seed, Bolton H. and Idriss, I. M., 1974, “A Simplified Procedure for Evaluating Soil
Liquefaction Potential,” Journal of Soil Mechanics, ASCE, Vol. 97, No. SM9, pp. 1249-
1273, September.
27. Strata-Tech, Inc. 1998, “Preliminary Geotechnical Investigation of Proposed Residential
Development at #17 Beacon Bay, Newport Beach, California,” W.O. 126098, October 23.
28. Tan, Siang, S., and Edgington, William J., 1976, "Geology and Engineering Geology of
the Laguna Beach Quadrangle, Orange County, California," California Division of Mines
and Geology, Special Report 127. 29. Terzaghi, Karl, Peck, Ralph B., and Mesri, Ghoamreza, 1996, “Soil Mechanics in
Engineering Practice, Third Edition,” John Wiley & Sons, Inc.
30. Tokimatsu, K., and Seed, H. B., 1987, “Evaluation of Settlements in Sands Due to
Earthquake Shaking,” Journal of Geotechnical Engineering, ASCE, Vol. 113, No. 8, pp.
861-878.
31. Vedder, J. G., Yerkes, R. F., and Schoellhamer, J. E., 1957, Geologic Map of the San
Joaquin Hills-San Juan Capistrano Area, Orange County, California, U. S. Geological Survey, Oil and Gas Investigations Map OM-193.
32. Zhang, G., Robertson, P. K., and Brachman, R. W. I., 2002, “Estimating Liquefaction-
induced Ground Settlements from CPT for Level Ground,” Canadian Geotechnical
Journal 39: 1168-1180.
PA2021-036
APPENDIX B
FIELD EXPLORATION
PA2021-036
APPENDIX B FIELD EXPLORATION PROGRAM
(13 Beacon Bay)
R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
General
Subsurface conditions were explored by excavating two borings on January 21, 2021. B-1 was a
6” diameter hollow-stem auger boring drilled to a depth of 14.5 feet using a Tripod drill rig.
Additionally, one hand-auger boring was advanced to a depth of 9 feet. The approximate
locations of the borings are shown on the Geotechnical Plot Plan, Figure 1. The Boring Logs are included as Figures B-2 and B-3. A Key to Logs is included as Figure B-1. Excavation of the
borings was observed by our field geologist who logged the soils and obtained samples for
identification and laboratory testing.
Exploratory excavations for the current investigation were located in the field by pacing from
known landmarks. Their locations as shown are, therefore, within the accuracy of such
measurements.
Sample Program
1. Drill Rig - Standard Penetration Tests (SPT) were performed to determine the in-place
relative densities and consistencies of the underlying soils. The test involves the number of blows it takes for a 140-pound hammer falling 30-inches to drive a 2-inch (outer
diameter)/ 1 3/8-inch (inner diameter) split spoon sampler (ASTM D1586). These blow
counts are given in blows per 6-inch driving interval for a sample with a length of 18-
inches. SPT samples were immediately sealed in individual plastic bags.
2. Bulk samples representative of subsurface conditions were collected from the
excavations and sealed in plastic bags.
Summary
The soils were classified based on field observations and laboratory tests. The classification is in
accordance with ASTM D2487 (the Unified Soil Classification System). Collected samples were
transported to the laboratory for testing. Groundwater was encountered at depths of 5.5 feet
and 6.5 feet in Borings B-1 and HA-1, respectively, on January 21, 2021.
PA2021-036
UNIFIED SOIL CLASSIFICATION CHART
CLEANGRAVELS
GRAVELWITHFINES
CLEANSANDS
SANDSWITHFINES
GW
GP
GM
GC
SW
SP
SM
SC
ML
CL
OL
MH
CH
OH
PT
GROUPSYMBOLS SYMBOLMAJOR DIVISIONS TYPICAL NAMES
HIGHLY ORGANIC SOILS
SILTS AND CLAYS:
Liquid Limit 50% or less
SILTS AND CLAYS:
Liquid Limit greater
than 50%
Well graded gravels and gravel-sand mixtures, little orno fines
Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays
Poorly graded gravels and gravel-sand mixtures, littleor no fines
Silty gravels, gravel-sand-silt mixtures
Clayey gravels, gravel-sand-clay mixtures
Well graded sands and gravelly sand, little or no fines
Poorly graded sands and gravelly sands, little or nofines
Silty sands, sand-silt mixtures
Clayey sands, sand-clay mixtures
Inorganic silts, very fine sands, rock flour, silty orclayey fine sands
Organic silts and organic silty clays of low plasticity
Inorganic silts, micaceous or diatomaceous fine sandsor silts, elastic clays
Inorganic clays of high plasticity, fat clays
Organic clays of medium to high plasticity
Peat, muck, and other highly organic soils
KEY TO LOGS
COARSE-GRAINED SOILS:
more than 50% retained on
No. 200 sieve (based on the
material passing the 3-inch
[75mm] sieve)
FINE-GRAINED SOILS:
50% or more passes
No. 200 sieve*
GRAVELS:
50% or more of
coarse fraction
retained
on No. 4 sieve
SANDS:more than 50% ofcoarse fractionpasses No. 4 sieve
Water level
SYMBOL
Figure B-1:
Unied Soil Classication
Chart / Key To Logs
NOTATION SAMPLER TYPE
C Core barrel
CA California split-barrel sampler with 2.5-inch outside diameter and a 1.93-inch inside diameter
D&M Dames & Moore piston sampler using
2.5-inch outside diameter, thin-walled tube
O Osterberg piston sampler using 3.0-inch
outside diameter, thin-walled Shelby tube
PTB Pitcher tube sampler using 3.0-inch outside diameter, thin-walled Shelby tube
S&H Sprague & Henwood split-barrel sampler
with a 3.0-inch outside diameter and a 2.43-inch inside diameter
SPT Standard Penetration Test (SPT)
split-barrel sampler with a 2.0-inch
outside diameter and a 1.5-inch inside diameter
ST Shelby Tube (3.0-inch outside diameter,
thin-walled tube) advanced with hydraulic
pressure
NR No Recovery
Modified California Sampler (3" O.D.)
Modified California Sampler, no recovery
Standard Penetration Test, ASTM D 1586
Standard Penetration Test, no recovery
Thin-walled tube sample using Pitcher barrel
Thin-walled tube sample, pushed or used Osterberg sampler
Disaggregated (bulk) sample
PA2021-036
DEPTHUSCSBLOW COUNTIN-PLACE SAMPLEBAG SAMPLEMOISTURE (%)DRY DENSITY (PCF)MATERIAL DESCRIPTION NOTES DEPTHLOG OF BORING
R MCCARTHY CONSULTING, INC.
5
10
15
20
25
5
10
15
20
25
SP
SP
EQUIPMENT: Tripod rig, 6” auger
SURFACE ELEVATION: 8.5 +/-
BORING NO: B-1
FILE NO: 8527-00 FIGURE B-2
BY: GM
BEACH/ MARINE DEPOSITS (Qe/Qm): Tan brown SAND, dry, loose
SPT1 at 3’: Gray brown SAND, moist, medium dense, medium grained, shell fragments
SPT2 at 5’: Dark gray silty CLAY, very moist, stiff, sulfur odor
SPT3 at 7’: Dark gray silty SAND, wet, medium dense, fine
grained, mica
SPT4 at 9’: Dark gray slightly silty SAND, wet, medium dense,
fine to medium grained
SPT5 at 11’: Dark gray SAND, wet, medium dense, medium grained, mica fragments
SPT6 at 13’: Dark gray SAND, wet, dense, medium grained
Total Depth: 14.5 feet
Groundwater at 5.5 feet
Caving at 7 to 14.5 feet
SITE LOCATION: 13 Beacon BayRear patioDATE: 1-21-21
“At x’:” always at front.
Only cap first letter of sentence.
Color, fineness SOIL TYPE,
material classification, moisture, density, other 356
1226
ML
227
SP
SP 5615
SP 51113
SP
30.7
9.0
45.9
21.3
24.1
23.024
Max Dry Density
(108 pcf, 17.5%) Chemical Tests
Grain Size
(2.2% passing #200)
Grain Size(26.2% passing #200) Atterberg Limits
(LL = 33, PI = 10)
Grain Size
(2.5% passing #200)
Grain Size
(3.7% passing #200)
CL
3 3
7
PA2021-036
DEPTHUSCSBLOW COUNTIN-PLACE SAMPLEBAG SAMPLEMOISTURE (%)DRY DENSITY (PCF)MATERIAL DESCRIPTION NOTES DEPTHLOG OF BORING
R MCCARTHY CONSULTING, INC.
5
10
15
20
25
5
10
15
20
25
SP
SP
EQUIPMENT: 4” hand auger
SURFACE ELEVATION: 9' +/-
BORING NO: HA-1
FILE NO: 8527-00 FIGURE B-3
BY: GM
SB at 2’: Gray to tan brown SAND, moist, medium dense, medium grained, large shell fragments
SB at 4’: Gray to tan brown SAND, moist, medium dense, medium grained
SB at 6’: Gray to tan brown SAND, moist, medium dense, fine
to medium grained, scattered shell fragments
SB at 8’: Dark gray silty SAND, wet, medium dense, sulfuric smell
SP
SP
SM
Total Depth: 9 feet
Groundwater at 6.5’
SITE LOCATION: 13 Beacon BayFront yard west planterDATE: 1-21-21
“At x’:” always at front.
Only cap first letter of sentence.
Color, fineness SOIL TYPE,
material classification, moisture, density, other
Upper 6”: Dark brown silty SAND, moist, medium dense, roots, planter soil
MARINE DEPOSITS (Qm):
PA2021-036
APPENDIX C
LABORATORY TESTING
PA2021-036
APPENDIX C
LABORATORY TESTING
(13 Beacon Bay)
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
The laboratory testing program was designed to fit the specific needs of this project and was
limited to testing the soil samples collected during the on-site exploration. The test program was
performed by our laboratory and supplemented with testing by NMG Geotechnical, Inc.
Soils were classified visually and per the results of laboratory testing according to ASTM D2487,
the Unified Soil Classification System (USCS). A Key to Logs is included as Figure B-1. The soil
classifications are shown on the Boring Logs, Figures B-2 and B-3. Density characteristics of the
soils encountered were determined by performing in-situ Standard Penetration Tests (SPT) in the
undisturbed soil as the borings were advanced. N-Values and soil classifications are shown on the
Boring Logs, Appendix B.
Maximum Density
The maximum dry density and optimum moisture content relationships were determined for
representative samples of the on-site soils. The laboratory standard used was ASTM D1557. The
test results are presented below in Table C-1 and on Figure C-1.
TABLE C-1
RESULTS OF MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT
ASTM D1557
Gradation
Particle size analysis consisting of mechanical sieve analysis were performed on representative
samples of the on-site soils in accordance with ASTM D 1140 and C-136. The test results are
presented on Figures C-2.
The percentage of particles passing the No. 200 (75μm) sieve are tabulated in Table C-3 below:
TABLE C-2
Grain Size – Fines Content
Location Classification Percent Fines
(Passing #200) Figure No.
B-1 @ 3’SP 2.2% C-2
B-1 @ 6.5’SM/SC 26.2% C-3
B-1 @ 9’SP 2.5% C-4
B-1 @ 13’SP 2.5% C-5
Test
Location
Soil
Classification
Soil Description Maximum Dry
Density (pcf)
Optimum
Moisture Content
(%)
B-1 @ 0-5’ SP Light brown SAND 108.0 17.5
PA2021-036
APPENDIX C
LABORATORY TESTING
(13 Beacon Bay)
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
Atterberg Limits
Atterberg Limits tests consisting of Liquid Limit and Plastic Limit determinations (ASTM D4318)
were done to evaluate the clay fraction characteristics of the materials encountered. A wide variety
of soil engineering properties have been correlated to the Atterberg Limits tests and they are also
used for soil classification. The representative sample tested for Atterberg limits was determined to
be non-plastic. The results of the Atterberg Limits testing is presented on Figure C-6 and in Table
C-3 below.
ATTERBERG LIMITS TABLE C-3
Test
Location
Soil
Classification Liquid Limit Plasticity Index
B-1 @ 6.5’ SM 33 10
Chemical Testing
Sulfate test results indicated low soluble sulfates as shown below in Table C-4:
SULFATE TABLE C-4
Test
Location
Soil
Classification
Soluble Sulfates
(mg/kg)
ASTM D4327 Sulfate Exposure
B-1 @ 0-5’SP <500 Low
PA2021-036
Date:C-1
Sample Identification B-1 @ 0-5'
MAXIMUM DENSITY & OPTIMUM MOISTURE CONTENT DETERMINATION
File No.: 8527-00 January - 2021 Figure:
Sample Description Brown Sand
Maximum Dry Density (pcf)108.0
Optimum Moisture Content (%)17.5
90.0
95.0
100.0
105.0
110.0
115.0
120.0
125.0
130.0
135.0
140.0
0 5 10 15 20 25 30Dry Density (pcf)Moisture Content (%)
2.60
2.65
2.70
PA2021-036
CUFile No.: 8527-00 Date:SILTSPSAMPLE IDENTIFICATION Coarse2.2FineJanuary 2021LOCATIONDEPTH (FT)SOIL DESCRIPTION3'SAND COBBLEGRAVELB-1PARTICLE SIZE ANALYSIS COMPARISONCCMediumC-2Figure No.:2.3 1.1USCSCLAYPASSING NO. 200 (%)Brown SAND01020304050607080901000.0010.0100.1001.00010.000100.000PERCENT PASSINGPARTICLE SIZE (MILLILMETERS)PARTICLE SIZE (INCHES OR SIEVE NO.)3" 1 1/2" 3/4" 3/8" 4 10 20 40 60 100 200PA2021-036
C-3Figure No.:68.3 11.7January 2021B-1PARTICLE SIZE ANALYSIS COMPARISONFile No.: 8527-00 Date:CLAYPASSING NO. 200 (%)Brown Silty SANDSAMPLE IDENTIFICATIONLOCATION COBBLEGRAVELSANDSILTSOIL DESCRIPTION6.5'CCSMMedium Coarse26.2FineCUUSCSDEPTH (FT)01020304050607080901000.0010.0100.1001.00010.000100.000PERCENT PASSINGPARTICLE SIZE (MILLILMETERS)PARTICLE SIZE (INCHES OR SIEVE NO.)3" 1 1/2" 3/4" 3/8" 4 10 20 40 60 100 200PA2021-036
CUFile No.: 8527-00 Date:SILTSPSAMPLE IDENTIFICATION Coarse2.5FineJanuary 2021LOCATIONDEPTH (FT)SOIL DESCRIPTION9'SAND COBBLEGRAVELB-1PARTICLE SIZE ANALYSIS COMPARISONCCMediumC-4Figure No.:2.2 1.0USCSCLAYPASSING NO. 200 (%)Brown SAND01020304050607080901000.0010.0100.1001.00010.000100.000PERCENT PASSINGPARTICLE SIZE (MILLILMETERS)PARTICLE SIZE (INCHES OR SIEVE NO.)3" 1 1/2" 3/4" 3/8" 4 10 20 40 60 100 200PA2021-036
SAMPLE IDENTIFICATION Coarse3.7FineJanuary 2021USCSCLAYPASSING NO. 200 (%)Brown SANDCUSAND COBBLEGRAVELB-1PARTICLE SIZE ANALYSIS COMPARISONFile No.: 8527-00 Date:SILTSPMediumC-5Figure No.:2.0 1.0LOCATIONDEPTH (FT)SOIL DESCRIPTION13'CC01020304050607080901000.0010.0100.1001.00010.000100.000PERCENT PASSINGPARTICLE SIZE (MILLILMETERS)PARTICLE SIZE (INCHES OR SIEVE NO.)3" 1 1/2" 3/4" 3/8" 4 10 20 40 60 100 200PA2021-036
C-6
ATTERBERG LIMITS
File No.: 8527-00
LOCATION DEPTH (FT)
B-1 6.5'10 33
Date:January 2021 Figure No.:
PLASTICITY
INDEX
LIQUID
LIMIT USCS
ML-CL
SAMPLE IDENTIFICATION
25
30
35
40
45
1 10 100Moisture Content (%)Number of Blows
Flow Curve
MH or OH
ML or OLCL-ML
0
10
20
30
40
50
60
70
0 102030405060708090100Plasticity Index (PI)Liquid Limit (LL)
PA2021-036
Sample Compacted
Moisture
(%)
Compacted
Dry Density
(pcf)
Final
Moisture
(%)
Volumetric
Swell
(%)
Expansion
Index1
Value/Method
Expansive
Classification2 Soluble
Sulfate
(%)
Sulfate
Exposure3
B-1 0-5' -- -- -- -- -- -- -- 0.05 S0
Test Method: ASTM D4829 HACH SF-1 (Turbidimetric)
Notes: 1. Expansion Index (EI) method of determination:
[A] E.I. determined by adjusting water content to achieve a 50 ±2% degree of saturation
[B] E.I. calculated based on measured saturation within the range of 40% and 60% 2. ASTM D4829 (Classification of Expansive Soil) 3. ACI-318-14 Table 19.3.1.1 (Requirement for Concrete Exposed to Sulfate-Containing Solutions)
Expansion Index
and Soluble
Sulfate
Test Results
(FRM001 Rev.5)
Project No. 20132-11 Project Name: R. McCarthy / 13 Beacon Bay (8527-00)
NMG
PA2021-036
APPENDIX D
STANDARD GRADING GUIDELINES
PA2021-036
APPENDIX D STANDARD GRADING GUIDELINES
(13 Beacon Bay)
R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
GENERAL
These Guidelines present the usual and minimum requirements for grading operations observed
by R McCarthy Consulting, Inc., or its designated representative. No deviation from these
guidelines will be allowed, except where specifically superseded in the geotechnical report
signed by a registered geotechnical engineer.
The placement, spreading, mixing, watering, and compaction of the fills in strict accordance
with these guidelines shall be the sole responsibility of the contractor. The construction,
excavation, and placement of fill shall be under the direct observation of the geotechnical
engineer or any person or persons employed by the licensed geotechnical engineer signing the
soils report. If unsatisfactory soil-related conditions exist, the geotechnical engineer shall have
the authority to reject the compacted fill ground and, if necessary, excavation equipment will be
shut down to permit completion of compaction. Conformance with these specifications will be discussed in the final report issued by the geotechnical engineer.
SITE PREPARATION
All brush, vegetation and other deleterious material such as rubbish shall be collected, piled and
removed from the site prior to placing fill, leaving the site clear and free from objectionable
material.
Soil, alluvium, or rock materials determined by the geotechnical engineer as being unsuitable
for placement in compacted fills shall be removed from the site. Any material incorporated as
part of a compacted fill must be approved by the geotechnical engineer.
The surface shall then be plowed or scarified to a minimum depth of 6 inches until the surface
is free from uneven features that would tend to prevent uniform compaction by the equipment
used. After the area to receive fill has been cleared and scarified, it shall be disced or bladed by
the contractor until it is uniform and free from large clods, brought to the proper moisture
content and compacted to minimum requirements. If the scarified zone is greater than 12
inches in depth, the excess shall be removed and placed in lifts restricted to 6 inches.
Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septic tanks,
wells, pipe lines or others not located prior to grading are to be removed or treated in a manner
prescribed by the geotechnical engineer.
MATERIALS
Materials for compacted fill shall consist of materials previously approved by the geotechnical
engineer. Fill materials may be excavated from the cut area or imported from other approved
sources, and soils from one or more sources may be blended. Fill soils shall be free from
organic (vegetation) materials and other unsuitable substances. Normally, the material shall contain no rocks or hard lumps greater than 6 inches in size and shall contain at least 50
percent of material smaller than 1/4-inch in size. Materials greater than 4-inches in size shall be
placed so that they are completely surrounded by compacted fines; no nesting of rocks shall be
PA2021-036
APPENDIX D STANDARD GRADING GUIDELINES
(13 Beacon Bay)
R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
permitted. No material of a perishable, spongy, or otherwise of an unsuitable nature shall be
used in the fill soils.
Representative samples of materials to be utilized, as compacted fill shall be analyzed in the
laboratory by the geotechnical engineer to determine their physical properties. If any material
other than that previously tested is encountered during grading, the appropriate analysis of this
material shall be conducted by the geotechnical engineer in a timely manner.
PLACING, SPREADING, AND COMPACTING FILL MATERIAL
Soil materials shall be uniformly and evenly processed, spread, watered, and compacted in thin
lifts not to exceed 6-inches in thickness. Achievement of a uniformly dense and uniformly
moisture conditioned compacted soil layer should be the objective of the equipment operators
performing the work for the Owner and Contractor.
When the moisture content of the fill material is below that specified by the geotechnical
engineer, water shall be added by the contractor until the moisture content is near optimum as
specified. Moisture levels should generally be at optimum moisture content or greater.
When the moisture content of the fill material is above that specified by the geotechnical
engineer, the fill material shall be aerated by the contractor by blading, mixing, or other satisfactory methods until the moisture content is near the specified level.
After each layer has been placed, mixed, and spread evenly, it shall be thoroughly compacted
to 90 percent of the maximum laboratory density in compliance with ASTM D: 1557 (five layers). Compaction shall be accomplished by sheepsfoot rollers, vibratory rollers, multiple-
wheel pneumatic-tired rollers, or other types of acceptable compacting equipment. Equipment
shall be of such design that it will be able to compact the fill to the specified density.
Compaction shall be continuous over the entire area and the equipment shall make sufficient
passes to obtain the desired density uniformly.
A minimum relative compaction of 90 percent out to the finished slope face of all fill slopes will be required. Compacting of the slopes shall be accomplished by backrolling the slopes in
increments of 2 to 5 feet in elevation gain or by overbuilding and cutting back to the compacted
inner core, or by any other procedure, which produces the required compaction.
GRADING OBSERVATIONS
The geotechnical engineer shall observe the fill placement during the course of the grading
process and will prepare a written report upon completion of grading. The compaction report
shall make a statement as to compliance with these guidelines.
As a minimum, one density test shall be required for each 2 vertical feet of fill placed, or one for each 1,000 cubic yards of fill, whichever requires the greater number of tests; however, testing
should not be limited based on these guidelines and more testing is generally preferable.
PA2021-036
APPENDIX D STANDARD GRADING GUIDELINES
(13 Beacon Bay)
R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
Processed ground to receive fill, including removal areas such as canyon or swale cleanouts,
must be observed by the geotechnical engineer and/or engineering geologist prior to fill
placement. The contractor shall notify the geotechnical engineer when these areas are ready for
observation.
UTILITY LINE BACKFILL
Utility line backfill beneath and adjacent to structures; beneath pavements; adjacent and
parallel to the toe of a slope; and in sloping surfaces steeper than ten horizontal to one vertical
(10:1), shall be compacted and tested in accordance with the criteria given in the text of this
report. Alternately, relatively self-compacting material may be used. The material specification
and method of placement shall be recommended and observed by the soil engineer, and
approved by the geotechnical engineer and Building Official before use and prior to backfilling.
Utility line backfill in areas other than those stated above are generally subject to similar
compaction standards and will require approval by the soil engineer.
The final utility line backfill report from the project soil engineer shall include an approval statement that the backfill is suitable for the intended use.
PROTECTION OF WORK
During the grading process and prior to the complete construction of permanent drainage
controls, it shall be the responsibility of the contractor to provide good drainage and prevent
ponding of water and damage to adjoining properties or to finished work on the site.
After the geotechnical engineer has finished observations of the completed grading, no further
excavations and/or filling shall be performed without the approval of the geotechnical engineer.
PA2021-036
APPENDIX E
RESULTS OF
LIQUEFACTION ANALYSES
PA2021-036
R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
Table E-1
Results of Liquefaction Analyses
Summary
13 Beacon Bay
Smax
Figure Condition Boring # (inch)
E-1/E-2 Existing B-1 0.83
Smax = Calculated seismically induced settlement of potential liquefiable and dry sand layers in Boring B-1.
Please see the associated figures for additional details.
Computation: GeoAdvanced GeoSuite Software Version 2.4.2.21, developed by Fred Yi, PhD, PE, GE
www.geoadvanced.com
PA2021-036
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150 Newport Beach, CA 92660
Phone 949-629-2539
APPENDIX F
SEISMICITY DATA
PA2021-036
ASCE 7 Hazards Report
Address:
13 Beacon Bay
Newport Beach, California
92660
Standard:ASCE/SEI 7-16
Risk Category:II
Soil Class:D - Default (see
Section 11.4.3)
Elevation:9.55 ft (NAVD 88)
Latitude:
Longitude:
33.61006
-117.898883
Page 1 of 3https://asce7hazardtool.online/Tue Jan 26 2021
PA2021-036
SS : 1.384
S1 : 0.492
Fa : 1.2
Fv : N/A
SMS : 1.661
SM1 : N/A
SDS : 1.107
SD1 : N/A
TL : 8
PGA : 0.606
PGA M : 0.727
FPGA : 1.2
Ie : 1
Cv : 1.377
Seismic
Site Soil Class:
Results:
Data Accessed:
Date Source:
D - Default (see Section 11.4.3)
USGS Seismic Design Maps
Ground motion hazard analysis may be required. See ASCE/SEI 7-16 Section 11.4.8.
Tue Jan 26 2021
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Additional Calculations:
SM1 =(FV)(S1)
Fv = 1.808 for S1 = 0.492 g per Table 1613A.2.3(2)
Therefore, SM1 = (1.808)(.492) = 0.890 g
SD1 = (2/3)(SM1) = (2/3)(0.890) = 0.593 g
PA2021-036
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