HomeMy WebLinkAboutPA2022-148_20220712_Geotechnical Investigation_07-12-22
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
Phone 949-629-2539 | Email info@rmccarthyconsulting.com
July 12, 2022
CDM Investors LLC File No: 8634-00 c/o Gus and Kyndra Dahleh Proposal No: P1-8634
331 Poinsettia Avenue
Corona del Mar, California 92625
Subject: Geotechnical Investigation
Proposed New Custom Home
Lot 1, Block 331
2516 and 2518 Bayside Drive
Corona del Mar, California
APN: 459-114-10
INTRODUCTION
This report presents the results of our geotechnical investigation for 2216-2218 Bayside Drive in
Corona del Mar, California, which was performed to determine site and regional geotechnical conditions pertinent to the residential construction currently proposed for the subject property.
Analyses for this investigation are based upon preliminary plans for the project prepared by
Brandon Architects. The plans indicate that a two-story custom home with a partial basement first
level, attached garage and a roof deck are proposed for the site. 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. Site 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 formulation of which are partially
dependent upon recommendations presented herein.
Project Authorization
The work performed was per your request based on our Proposal No: P1-8634, dated
September 24, 2021 and subsequent authorization.
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Scope of Investigation
The scope of services included the following:
1. Review of collected geologic, geotechnical engineering and seismological reports,
maps and aerial photographs pertinent to the subject site. A reference list is
included in Appendix A.
2. Subsurface exploration consisting of three soil borings drilled with a hollow stem
auger to depths of 13 to 26 feet and two hand auger borings to depths of 5.5 to 9.5
feet. Locations of the exploratory excavations are shown on the Geotechnical Plot
Plan, Figure 1.
3. Logging and sampling of exploratory borings, including collection of soil samples for
laboratory testing. The logs of the exploration are included in Appendix B.
4. Laboratory testing of soil samples representative of subsurface conditions. The test
results are presented in Appendix C.
5. Geotechnical engineering and geologic analyses of collected data, including
preparation of Geotechnical Cross-Sections, A-A’ and B-B’, Figures 2 and 3.
6. Preparation of this report containing our geotechnical recommendations for the
design and construction in accordance with the current 2019 California Building
Code (CBC) and for use by your design professionals and contractors.
Site Description
The subject property is located on the northeast side of Bayside Drive, east of the intersection
of Bayside Drive and Carnation Avenue in Corona del Mar, California, as shown on the attached Location Map, Figure 4. The property is bordered on the northeast by uphill, developed
residential properties along Dahlia Avenue, by a driveway and parking easement area on the
southeast, by an access easement and 2514 Bayside Drive on the northwest and by a greenbelt
easement on the southwest.
The Topographic Map prepared by Apex Land Surveying Inc. (Reference 1) was used as a base
map for our Geotechnical Plot Plan, Figure 1. The lot has a rectangular shape and an area of approximately 3,540 square feet (realtor.com). Topographically, the site slopes to the
southwest and is cut into a former hillside along a ravine. Exterior grade changes are
accommodated by stairs and retaining walls. The lot elevations are shown on the survey at
approximately 63 to 75 feet (NAVD88) along the northeast side and approximately 58 to 61 feet
along the southwest side. Bayside Drive slopes downward to the west and is lower than the site
by approximately 6 to 10 feet. Curb elevations along this segment of Bayside Drive range from
approximately 53 to 50 feet. The park area between the lot and Bayside Drive is approximately
36 to 50 feet wide and slopes at gentle gradients to the street. There are a several retaining
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walls supporting the previous cuts into the hillside. The existing retaining walls are estimated to range from about 3 feet to 12 feet high.
There is an existing duplex on the property reportedly constructed around 1972. The
construction is assumed to be typical wood frame, stucco, and wood siding. The rear and
portions of the side walls of the house retain hillside cuts.
Vegetation on the lot includes lawn, shrubs, ground covers, hedges and trees. The park
easement is planted with grass lawns, shrubs, groundcover, hedges and trees. There is a
meandering sidewalk following Bayside Drive. Low-height retaining structures are also in place
within the landscaped park area. The driveway and parking easement on the southeast side is
paved with concrete. Portions of the slope along the northeast property line are retained with a
pipe-and -board revetment system and stacked concrete walls.
Yard drainage is moderately developed with surface flow directed downhill toward the street. No areas of poor drainage were observed. Minor separations at wall joints and in concrete
pavement and hardscape were observed. These were typical and commensurate with the age
of the structure. The interiors of the duplex were not observed. There were no observations that would indicate adverse soil movement on the exterior of the property.
Proposed Development
We understand that the proposed development will consist of the demolition of the existing structure to build a new multi-level single-family residence. The plans indicate that a two-story
custom home with a partial basement first level, attached garage and a roof deck are proposed
for the site. The new structure will be in a similar position as the existing structure. The partial
basement and lower-level excavation is expected to be done with shoring to protect the
adjoining properties where new walls are planned.
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 kip 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.
Other improvements are expected to include concrete patios, retaining walls, stairways,
sidewalks and landscaping. Roof gutters, sloped grades and area drains should also be installed
to collect surface drainage and direct it to approved outlet or collection areas.
GEOTECHNICAL CONDITIONS
Geologic Setting
The subject site lies within the Peninsular Ranges geomorphic province of southern California.
The property is situated at the seaward margin of a broad marine terrace of Quaternary aged
marine sediments/ old paralic deposits (Qt/Qop) that occurs along the coastal margin of the San
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Joaquin Hills. The marine terrace was developed as a wave cut terrace overlying Monterey Formation (Tm) sedimentary bedrock strata of Miocene age that was uplifted, then cut flat by
the onset of an encroaching ocean with resulting old paralic deposits (marine terrace and
subsequent alluvial terrace deposition) at the surface. Artificial fill soils were encountered at the
site in the exploratory borings directly over the bedrock on this lot. The bedrock is also exposed
along the sloping margins of the nearby canyons and coastal bluffs where past erosion has cut
into the terrace deposits and underlying bedrock. Bayside Drive follows the alignment of an
older, now filled, ravine that formerly extended west-southwest toward the harbor.
Earth Materials
The site is underlain by bedrock strata of the Monterey Formation of late Miocene age on the
basis of regional geologic maps (Figure 5). The bedrock is generally overlain by artificial fill and backfill. Material interpreted as bedrock landslide debris associated with the former hillside
along the ravine was encountered in Boring B-3 below the fill. There are also local areas of
residual fill soil placed as part of retaining wall backfills, grading for pavements and
landscaping.
Artificial fill at the site is expected to consist of retaining wall backfills, grading/leveling as a part
of past development and residual planter soils. Undocumented fill materials were evaluated as
part of our investigation and appear to be suitable for support of significant structural improvements below depths of approximately 5 feet. The upper 5 feet of the fill soil is
recommended to be removed as part of remedial grading and excavation. If some site retaining
walls are to remain in place, any new, adjacent foundations may be deepened to obtain support
below the existing foundations and fill soils. Our findings indicate that the fill soils increase in
thickness toward Bayside Drive. Shallow bedrock was encountered and is expected along the
rear of the property that was previously cut into the hillside. The depth of backfill and
undocumented soil at the site may vary but is generally expected to be on the order of zero to
12 feet thick below the planned structure.
The artificial fill varied in thickness from 5 to 13 feet in our exploratory borings. Laboratory test
results (Appendix C) indicate that the on-site fill materials have a medium expansion potential
(EI = 56). The fill materials are derived from the local bedrock and contain diatomaceous earth.
Moisture contents ranged from 17.2 to 31.8 percent in the tested fill materials along the front of
the existing structure. Wall backfill materials along the rear of the property (HA-1 and HA-2) had tested moisture contents that ranged from 14.2 to 28.4 percent. Dry density values ranged
from 67 to 99 pounds per cubic foot (pcf) in the fill and 74 pcf in the backfill materials.
Based on our exploratory borings, experience in the vicinity and descriptions in the references, the Monterey Formation consists of firm but friable, thinly bedded, light grey/brown/yellow
diatomaceous and siliceous shale with planar bedding surfaces displaying iron and manganese
staining and scattered sandstone and concretionary beds. Bedrock was encountered at depths
of 5 to 13 feet in our exploratory borings and consisted of pale brown to light gray siltstone.
Moisture contents ranged from 9.2 to 36.3 percent in the tested bedrock materials. Dry density
values within the bedrock materials ranged from 75 to 130 pounds per cubic foot (pcf). The
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Monterey formation materials in the local area can be moderately expansive with relatively low plasticity.
Bedrock interpreted to be old landslide debris was encountered at a depth of 13 feet in Boring
B-3 and consisted of olive-brown, yellow-brown to light gray siltstone. The bedrock appeared to
be disturbed, had lower sample blow counts and was wet at a depth of 19 feet. Moisture
contents ranged from 35.1 to 41.2 percent in the tested materials. A dry density value of 73
percent was determined for the sample at a depth of 15 feet.
Idealized profiles of the various materials encountered in the exploratory borings are depicted
on Figures 2 and 3, Geotechnical Cross-Sections A-A’ and B-B’.
Most materials derived on-site will recompact to produce acceptable structural fill; however, the
on-site materials may be difficult to mix and compact when the silt, clay and diatomaceous
contents are significant and moisture contents are relatively high. The fine-grained on-site soils are not suitable for use as retaining wall backfill. Organic materials, debris and other unsuitable
materials that may be present as part of the demolition should be hauled away and not used in
the recompacted fill.
Cuts into hard bedrock will be difficult below weathered zones and could generate oversized
rock. The majority of the on-site earth materials above the bedrock should excavate readily;
however, heavy duty grading equipment will be required to level out the excavation and reach
design depths. Rock breakers, jackhammers or chippers may be needed to cut into hard
bedrock outcrops if encountered in excavations.
Geologic Hazard
The geologic hazards at the site are primarily from shaking due to movement of nearby or
distant faults during earthquake events. The sloping ground at the site has been modified by
construction of retaining walls to create a relatively flat lot located on a sloping hillside terrace of older marine sediments. There is no adverse geologic structure, active faulting near the site,
shallow groundwater or other indications of geologic hazards that would affect the site as
further detailed below.
Structure
Our findings indicate that the site is developed on former hillside area that has been infilled at
the bottom and modified with retaining walls along the rear. The former sloping gradients have
been largely eliminated by past development on this and adjoining lots. Bedding structure in the area shown on regional geology maps indicate that the bedding generally dips at angles of
about and 22 to 26 degrees to the northwest (Morton and Miller, 1981) in the vicinity.
Consultant reports for this and adjoining sites indicate bedding at angles of approximately 22 to
60 degrees to the north/northeast. The bedding conditions are favorable to slope and retaining
wall stability. There is therefore no known adverse geologic bedding structure that is likely to
affect stability at the site. The State of California has mapped several geologic faults trending
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northwest-southeast in the vicinity of the site. The faults are within the underlying bedrock. The faults are considered inactive at this time; however, sympathetic movement may occur during
significant shaking on one of the nearby active fault traces.
Slope Stability
The significant areas of sloping ground at the subject site have been mostly replaced with
terraced pads and retaining walls. Global and surficial slope stability therefore exceed the
accepted minimum factors of safety. The stacked concrete retaining walls at the rear of the site
should be replaced with retaining structures that are structurally designed.
Groundwater
Groundwater was observed in Boring B-3 at a depth of 19 feet at the time of the investigation.
Perched groundwater may develop on engineered fill and bedrock as a result of rainfall,
irrigation and seepage from adjoining properties. Groundwater seepage is not anticipated to be
a significant design or construction constraint, provided proper surface drainage and
subdrainage systems are incorporated into the project.
Although no evidence of shallow groundwater was observed during our field investigation,
subdrains and waterproofing should be included in retaining wall design and construction as a
precaution against the development of hydrostatic wall loading and possible wall seepage.
Infiltration
The near surface fine-grained soils on this property have relatively low permeability rates due to the clay, silt and diatomaceous material content, which relates to the on-site infiltration rates.
On-site water infiltration is not recommended due to potential for future seepage and perched
water. Surface and subsurface drainage should be directed toward approved outlets.
Surficial Run-off
Proposed development should incorporate engineering and landscape drainage designed to
transmit surface and subsurface flow to the storm drain system or approved collection facilities via non-erosive pathways. Care should be taken to not allow water to pond or infiltrate soil
adjacent to foundation elements.
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.
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Based on criteria established by the California Division of Mines and Geology (CDMG), now referred to as the California Geological Survey, 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 refinements 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 "Special Studies Zones,” which requires special investigations for fault rupture to limit
construction over active faults.
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 site is not located near an active fault, or within a special studies zone for earthquake fault rupture. Inactive, northwest-trending faulting has been mapped to occur at depth under the
terrace deposits to the east-northeast in close proximity to the site. The closest active fault to
the site is the Newport Inglewood Fault (north branch) located approximately 2 to 3 kilometers
southwest of the site. As such, the potential for surface rupture at the site is very low, but the
site will experience shaking, during earthquake events on nearby or distant faults. Site
improvements should take into consideration the seismic design parameters outlined below.
Site Classification for Seismic Design
Seismic design parameters are provided in a later section of this report and in Appendix E 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.
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The results of our on-site field investigation, as well as nearby investigations by us and others, indicate that the graded site will be directly underlain by Class D (Default) artificial fill over Class
C and B soft to dense rock within the Monterey formation sandstone/siltstone bedrock.
Foundations will be embedded in compacted fill. In consideration of the fill soils at the
foundation levels, we recommend using a characterization of this property as a Class D
(Default) Site Classification.
Secondary Seismic Hazards
Review of the Seismic Hazards Zones Map (CDMG, 1997/1998) for the Newport Beach
Quadrangle, indicates the site is not located within a zone of required investigation for
earthquake-induced liquefaction and is within a zone of required investigation for landslide (see
Figures 7 and 8). This finding is in keeping with the results of our study. The landslide hazard
has been eliminated by past development on this and adjoining properties, which included fill
placement within the old ravine and cuts into the hillside with retaining wall construction.
Other secondary seismic hazards to the site include deep rupture, shallow ground cracking,
lurching with lateral movement and settlement. With the absence of active faulting on-site, the
potential for deep fault rupture is not present. 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. The potential for seismically-induced lurching and settlement to occur is considered remote for the site. The potential for tsunami inundation at the site elevation is nil
at the foundation levels.
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,
or be adversely affected by, adjacent properties, providing appropriate engineering
design, construction methods and care are utilized during construction.
2. The primary geotechnical considerations at the property will include the excavation for
the partial basement level construction, shoring for site excavation and retaining walls,
excavation to remove unsuitable soil materials, expansive soil considerations, drainage, subdrainage and property line constraints.
3. There are no geotechnical constraints that would preclude the proposed construction if
designed and constructed appropriately and in consideration of the property line, fill and
slope conditions.
4. The property is underlain by bedrock of the Monterey Formation. The bedrock is overlain
by landslide debris and artificial fill. The landslide debris is overlain by artificial fill.
5. The existing bedrock deposits are expected to be suitable for support of fill and new
structures except where disturbed by excavation or demolition. The existing fill and
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materials should be removed and replaced within the upper 5 feet as part of remedial grading. Bedrock materials should be removed to a depth of at least 2 feet below the
foundation and replaced as engineered fill.
6. The on-site materials have a medium expansion potential based upon the findings of our
investigation.
7. The expansive soil above the bedrock at the site should be addressed as part of the
structural design, grading and construction. Generally, a mat slab with a thickened edge
beam and extra reinforcement may be used for design of slabs and foundations on
expansive soils. Maintaining the as-graded moisture content or pre-soaking of the
subgrade soils is also required as part of the design.
8. If existing retaining walls remain through subsequent construction, removal of backfill
may be impractical. New foundations should extend to depths below any undocumented backfill materials and to a sufficient depth to avoid surcharge of the adjacent walls or
foundations.
9. Retaining wall and foundation plans will require further review by this office and should be forwarded to us for review, as they are prepared, in order to provide specific load
information for proposed walls and footings.
10. No active faults are known to transect the site and, therefore, the site is not expected to
be adversely affected by surface rupturing. It will, however, be affected by ground
motions from earthquakes during the design life of the residence. The potential for
seismically-induced liquefaction or landsliding affecting the proposed residence is considered to be very low.
11. Groundwater is not expected to be a concern during construction. Suitable drainage
elements need to be installed at retaining walls to mitigate possible transient seepage.
12. Adverse surface discharge onto or off the site is not anticipated provided proper civil
engineering design and post-construction site grading are implemented.
13. Concentrated water infiltration into the on-site near surface soils is not practical or
advisable due to low permeability rates in the fine-grained soils encountered during our
field investigation.
14. The proposed residence may be supported by a mat slab and foundation system
designed in consideration of the expansive soil conditions and supported entirely within geotechnically approved recompacted fill materials. Shoring is anticipated along property
line excavations.
15. Monitoring of adjoining properties and shoring elements will be required as part of the
construction.
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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 materials from the demolition, organic materials and
trash, should be removed and disposed of off-site. Subsurface elements of demolished
structures should be completely removed, including any basements, foundations, septic
tanks, cisterns, abandoned utility lines, etc.
3. Subgrade Preparation
Within at-grade slab areas for structures, excavations should be made to remove any
soils disturbed by demolition, unsuitable fill and surficial materials where encountered
within the building areas. A minimum removal depth of 5 feet is recommended in
surficial soil areas to provide uniform bearing conditions below foundation and slab
areas. Where bedrock material is encountered the removals may be reduced to a depth
that provides 24-inches of compacted, engineered fill below footings. Removals should
be followed by 6-inches of scarification and re-compaction. These remedial excavations
should be made within the planned building footprint and the influence zone of footings.
Excavations should extend to a depth that provides at least 24-inches of re-compacted
fill below footings. Deeper excavations may be necessary to remove unsuitable
materials, if encountered. Although not encountered in our exploratory borings, dry or
porous native soil zones should be excavated to suitable materials if exposed during
grading. Excavations should be replaced with compacted 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.
Shallow bedrock exposures may require specialized, heavy-duty equipment for on-site
excavations. The density of the bedrock is expected to vary across the site. Plans for all
earth retaining structures, drawn as part of the planned development, should be
forwarded to the Geotechnical Engineer prior to excavation.
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Subsurface materials are depicted on the Geotechnical Plot Plan, Figure 1, and in Cross-Sections A-A’ and B-B’, Figures 2 and 3. The cross-sections should be updated, if
necessary, when preliminary grading plans are prepared.
Shoring is anticipated to be required to accomplish remedial grading and construction of
new improvements due to the planned excavation depths, the presence of existing
retaining walls and grade differences along adjoining lots.
Removals below significant hardscape improvements such as driveways, patios, and
sidewalks should be sufficient to remove existing disturbed native and fill soil. Removal
depths of 24-inches are expected to be adequate in yard areas; however, boundary
conditions for removals under exterior improvements may be better addressed subsequent to demolition when excavation equipment can expose the site materials for
evaluation and when improvement limits are identified on the plan.
Removals should be followed by 6-inches of scarification and recompaction. Excavations
that require filling should be replaced with compacted engineered fill.
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 (but not as retaining wall backfill); however, silt, clay and diatomaceous materials may be difficult to
moisture condition and utilize in the fill. The Contractor should plan on possible difficult
mixing and compaction of the on-site materials. Uniform mixing and the use of a
compactor that provides a broad, uniform weight, such as with track-mounted equipment or a sheepsfoot roller (preferred over narrow tire wheel rolling) will generally
be more efficient for compaction. Fine-grained materials will also impact the expansion
potential of the foundation soils. 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.
On-site materials should be placed at above optimum moisture content and compacted
under the observation and testing of the Soil Engineer. Moisture contents should be
maintained in the time period between completion of grading and construction of the
foundation and slab. In our experience, periodic watering of the exposed graded surface
soils will help to maintain moisture, minimize tension cracks and reduce the effort required for pre-soaking.
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The recommended minimum density for compacted material is 90 percent of the
maximum density as determined by ASTM D1557.
5. Shrinkage and Bulking
Shrinkage losses for existing fill materials are expected to be on the order of 3 percent.
Additional clearing losses from demolition could result in volume reductions for available
fill soils. Some bulking of bedrock materials is likely to occur. The volume change due to
bulking will be dependent on overexcavation depths, the field moisture content at the
time of grading and the conditions during fill compaction.
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 silts with a medium expansion potential.
7. Compaction Standard
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. The recommended moisture content is above optimum per the
recommendations herein.
8. Temporary Construction Slopes
Temporary slopes exposing onsite materials should be cut in accordance with Cal/OSHA
Regulations. It is anticipated that the exposed onsite earth materials may be classified as Type B soil overlying Stable Rock. The fill materials appear to be relatively
stiff/medium dense below this site and are expected to be stable at expected cut
angles. Temporary cuts of 1:1 (horizontal: vertical) above the bedrock are expected be
appropriate for fill and colluvium/terrace deposits. Per usual City of Newport Beach
requirements, excavation cuts should be above a 1:1 or flatter plane extending
downward from the property line unless shoring is installed. The material exposed in
temporary excavations should be evaluated by the contractor and geotechnical consultant during excavation and construction.
Shoring should be anticipated where space limitations preclude temporary slope layback
and should be anticipated for portions of retaining walls constructed along and near the
side property margins. This applies to exterior retaining walls as well as house structure
subterranean retaining walls. Lateral support of adjacent public and private property
improvements should be maintained during grading and construction. The use of
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lagging or plates between shoring elements will be required for basement excavations. Excavations should be reviewed by the Geologist as these materials are exposed.
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. Unsupported cuts should not be allowed to dry out
and should not be left open for extended time periods.
9. Adjacent Property Assessments and Monitoring
The proposed excavations into hard or dense bedrock materials will cause vibrations and
sound pressure (noise) that may be potentially disturbing to occupants of neighboring
properties. If appropriate equipment and experienced operators and contractors perform
the excavations, it is unlikely that such vibrations will be sufficient to promote structural damage in the vicinity.
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 into bedrock materials. Vibration monitoring is,
therefore, highly recommended during demolition and installation of shoring.
• 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.
• Please note that these activities require coordination with your contractor and
some activities may not be part of our normal scope of work unless requested.
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
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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 - Design of Footings
1. General
It is anticipated that foundation elements for the residence will bear in compacted fill
and will utilize a mat slab foundation system.
The prepared subgrade materials are expected to be primarily derived from bedrock with medium expansion potential. When removed, mixed and replaced as compacted fill
the materials are expected to be in the medium expansion range; however, this will
depend on the distribution of these materials on the site. 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. Mat Slab Foundation System
A mat slab foundation system is recommended for the slab-on-grade construction at the
site. The allowable bearing capacity for a mat slab type system founded on the prepared
subgrade should not exceed 1,400 pounds per square foot. This value may be increased by one-third for short-term wind or seismic loading. A minimum slab thickness of 18-
inches is recommended. A continuous perimeter thickened edge to a minimum depth of
24-inches is recommended to reduce lateral moisture transfer below the slab. For design
of a mat foundation system, a modulus of subgrade reaction of 100 pounds per cubic
inch may be considered. Actual thickness, depths and widths of the foundation and slab
system should be governed by code requirements and the structural engineering design.
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All isolated pad footings should be tied by grade beams in not less than two directions (north-south/ east-west). A continuous perimeter footing to a minimum depth of 24-
inches is recommended to reduce lateral moisture transfer below the foundation and
slab in outdoor living areas such as covered patios, loggias, etc. A grade beam to a
depth of 24-inches should also be poured along garage door openings. Isolated
foundation elements that extend below the fill into terrace deposits should generally be
deepened to bedrock and evaluated on a case-by-case basis.
3. Settlement
Settlement for conventional foundations is anticipated to be less than 1-inch total and
¾-inch differential between adjacent similarly loaded columns or between shear walls (assumed 30-foot span), provided that the recommended site grading is implemented
first. These estimates should be confirmed when structural engineering plans are
prepared and foundation load conditions are determined.
4. Lateral Resistance
Lateral loads for foundation and slab design may be resisted by passive pressure forces developed in front of footings and by lateral sliding resistance acting at the base of
foundation elements. These load bearing values are to be used with the allowable stress
design load combinations specified in CBC Section 1605.3. An allowable lateral bearing
pressure of 200 pounds per square foot per foot of depth equivalent fluid pressure may be assumed for shallow foundations. Lateral resistance for deepened foundations is
discussed above. Resistance to sliding can be calculated using a coefficient of friction of
0.25. These values may be used in combination per CBC 2019 Section 1806.3.1. The values for lateral load resistance may be increased by one-third for the alternative basic
load combinations of CBC Section 1605.3.2 that include wind or seismic loads.
5. Foundation Reinforcement
Reinforcement for mat slab-type foundations should be designed by the Structural
Engineer; however, unreinforced slabs are not acceptable. Therefore, as a minimum,
reinforcement should consist of No. 4 bars placed 12-inches on center in both directions
top and bottom. Two No. 5 bars should be placed at the top and bottom of any isolated
continuous footings or grade beams in order to resist potential movement due to various
factors such as subsurface imperfections and seismic shaking.
6. Footing Setbacks from Retaining Walls
Foundations should be deepened to provide a sufficient embedment to avoid surcharge of any retaining walls in the vicinity. In addition, foundations should not achieve support
directly on undocumented backfill material. In general, foundations should extend below
a plane extending up from the bottom of adjacent wall footings at an angle of 2:1
(Horizontal: Vertical).
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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) -117.876855 W
Site Latitude (degrees) 33.599728 N
Ss (g) 1.361
S1 (g) 0.483
SMs (g) 1.634
SM1 (g) 0.878
SDs (g) 1.089
SD1 (g) 0.585
Fa 1.2
Fv 1.817
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 E.
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Slab-On-Grade Construction
Concrete slabs should be designed in accordance with the 2019 California Building Code. The
on-site soils are expected to exhibit a medium expansion potential. Concrete floor slabs should
be at least 18-inches thick (actual). Slabs should consist of properly reinforced concrete
materials. Reinforcement should be in accordance with the structural engineering design;
however, unreinforced concrete slabs are not recommended. Therefore, as a minimum,
reinforcement should consist of No. 4 bars placed at 12 inches on center in both directions at
the top and bottom of the slab.
Partial basement and subterranean area slabs should be appropriately waterproofed.
Subdrainage should be provided below slab elevations along the exterior at the base of all
subterranean walls. Subdrains should flow to an approved outlet with precautions to prevent
backup of water into the perforated portions of the systems. The drains, waterproofing and
preventive measures should be shown on the grading plans.
Slabs should be underlain by 4-inches of open-graded gravel and provided with additional below slab subdrains. Slab underlayment and waterproofing 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 the
gravel or waste slab in accordance with the requirements of ASTM E1745 and E1643. Gravel, if
utilized, should be covered with a layer of woven geofabric, such as Mirafi 140N or similar, prior
to placing sand or the vapor retarder/barrier. Slab subgrade soils should be well-moistened
prior to placement of the waste slab or vapor retarder. All subgrade materials should be geotechnically approved prior to placing the gravel for the slab underlayment.
Exterior flatwork elements should be a minimum 5-inches thick (actual) and reinforced with No.
3 bars at 18-inches on center both ways. Slab subgrade soils should be well-moistened prior to
placing concrete.
Shoring
Excavations for remedial grading and planned retaining walls at the site may necessitate the
use of shoring if slope laybacks steeper than 1:1 from the property line to the bottom of the
overexcavation are necessary. Selection of an appropriate shoring system should consider the
potential effects of vibrations, deflections and lateral support of adjoining properties. The
current City of Newport Beach policy requires that temporary shoring along property lines be
designed for At-Rest (Not free to rotate) lateral earth pressures. This aspect of the design is left
to the Structural Engineer. We anticipate that soldier pile and lagging systems will be used for
shoring.
Design lateral loading values for a cantilevered shoring system should be based upon an
equivalent fluid pressure of 65 pounds per cubic foot at-rest pressure for level backfill conditions. Recommended lateral passive resistance for soldier piles founded in undisturbed
bedrock is 400 pounds per cubic foot, acting on a tributary area of twice the pile diameter. The
passive pressure should not exceed 6,000 psf. Passive resistance may start at a depth of 3 feet
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below grade along the base of the exposed segment of pile (24-inch diameter). Piles may use an allowable bearing value of 6,000 pounds per square foot for a minimum 10-foot embedment
depth into competent bedrock.
We anticipate that shoring will be within fill, terrace deposits and bedrock material. It is the
contractor’s responsibility to develop appropriate means and methods of construction to avoid damage to adjacent properties. Proper installation of shoring is the responsibility of the
contractor. The adjacent property owners should be notified and advised of the risks and the
owner and builder should provide arrangements to repair possible damages. Existing soil conditions behind shoring elements may result in collapse and caving of soils during removal of
shoring. Permanent shoring is therefore recommended unless the contractor can demonstrate a
safe system for removal of shoring elements.
All soldier pile installations should be observed by the geotechnical consultant to verify that the
intent of the recommendations herein is implemented. After the soldier piles have been placed
and backfilled, site excavations may begin. Sufficient curing time for concrete and grout should
be allowed before excavating. Care should be taken to make sure that the lagging drops into
place as the excavations advance. Gaps in the lagging or behind the lagging are undesirable
and could cause undermining of adjacent soils and should be immediately filled with grout or
slurry. Subdrains should be installed between shoring and permanent retaining walls below the
basement slab elevation. Maximum lagging cuts shall not exceed 5 vertical feet and shall be carried out in alternating bays prior to lagging and grouting adjoining sections either above or
below (or in adjoining bays). The geologist should be on-site to observe excavation cuts for
lagging. It is the responsibility of the Contractor to notify our office prior to the start of drilling
and lagging operations for scheduling.
Prior to drilling and installing the shoring system, the shoring plans and calculations should be
forwarded to the project geotechnical consultant for review to confirm that the shoring has
been designed in accordance with the recommendations herein.
Lateral Earth and Bearing Pressures for Retaining Walls
Design lateral loading values for cantilevered retaining walls should be based upon the
following:
Foundations
Bearing Capacity = 1,400 psf (24-inch embedment)
Note: See applicable text above where deepened foundations are required in slope or wall areas.
Lateral Earth Pressures
Active Earth Pressure = 50 psf/ft (level backfill)
Active Earth Pressure = 70 psf/ft (2:1 sloping backfill)
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Restrained Condition = 60 psf/ft at-rest loading (shoring, level b/fill, on-site soil)
Passive Earth Pressure = 400 psf/ft (bedrock)
Resistance to Sliding = 0.25
Other topographic and structural surcharges should be addressed by the Structural Engineer, as
appropriate. Stacked walls should include applied surcharges from the uphill walls as
appropriate.
Lateral Earth Pressures for Shoring, Retaining Walls and Foundations
Design lateral loading values for cantilevered shoring systems, retaining walls and structure
foundations should be based upon the following for level backfill conditions:
Structural Design of Retaining Walls
1. Earthquake Loads on Retaining Walls
The structural engineer should determine which retaining walls at the site within their
purview 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.
Walls along the rear slope greater than 6 feet in height may be considered using an
additional dynamic load (∆PaE) of 45 pounds per cubic foot equivalent fluid pressure.
This force is presumed to act at 0.33H above the base of the wall (Al Atik and Sitar,
ASCE 2010). This value is preliminary and we recommend that each wall be evaluated individually as plans are prepared. Note that the load diagrams and lateral pressures
may vary based on wall height, orientation and backfill conditions. We therefore
recommend that structural design not proceed until each wall is addressed by the
geotechnical engineer based on the planned retaining wall configurations.
2. Foundation Bearing Values for Walls
Footings for retaining walls may be designed in accordance with the recommendations provided above and should be embedded in compacted fill or undisturbed bedrock at a
minimum depth of 24-inches below the lowest adjacent grade.
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3. Wall Backfill
The expansive on-site soils are generally not suitable for use as retaining wall backfill for
new walls. Imported backfill, if used, should consist of select, non-expansive sand 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. Approval of wall backdrains should be obtained prior to backfill. Gravel wall backfill material should be separated from on-site soil materials, along back cuts and at
interfaces with other materials with a suitable filter fabric such as Mirafi 140N and
capped with on-site soil or concrete.
Fill and backfill 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. 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.
4. 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.
Subterranean retaining walls should be provided with an approved drain at the base of
the backfill. Subdrains should consist of a 4-inch diameter perforated pipe (Schedule 40
or similar) surrounded by at least 3 cubic feet per foot of ¾-inch gravel wrapped in geofabric (Mirafi 140N or similar). Perforations should be placed down and filter fabric
should be lapped at least 12-inches at seams.
Exterior (non-living area) retaining walls should be provided with an approved drain at
the base of the backfill. Subdrains should consist of a 4-inch diameter perforated pipe
(Schedule 40 or similar) surrounded by at least 1 cubic foot per foot of 3/4-inch gravel
wrapped in geofabric (Mirafi 140N or similar). Perforations should be placed down and
filter fabric should be lapped at least 12-inches at seams. Weep holes or open head
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joints may be included for low-height garden walls with a height of less than 30-inches as an alternative to a pipe subdrain; however, the geofabric wrapped gravel burrito at
the base of the wall is recommended to reduce clogging of the weep openings.
Shotcrete walls may incorporate an approved drainage board material with an outlet
pipe at the base installed per the manufacturer’s recommendations.
5. Dampproofing and Waterproofing
Waterproofing should be installed in accordance with the architectural specifications or
those of a waterproofing consultant. A Miradrain type system is recommended for the height of the basement wall backfills. Waterproof systems and materials should be
installed in accordance with manufacturer’s recommendations, based on geologic
conditions. The wall waterproofing should tie into the underslab waterproofing so that
there are no permeable seams in the building envelope. The criteria in Section 1805 of
the 2016 CBC should be followed as a minimum.
6. Shoring
The placement of shoring should consider that on-site soils may have local variably loose
or fractured zones that may be prone to caving and or settlement. Vibratory techniques
for placement of piles or steel sheet lagging should not be utilized, as damage to adjoining property improvements may otherwise occur. It is the Contractor’s
responsibility to develop appropriate means and methods of construction to avoid
damage to adjacent properties. Casing of pile excavations is at times necessary in granular materials such as terrace deposits as well as in fractured bedrock materials.
The use of temporary shoring with the intent to remove the shoring elements following
wall construction and backfill is not recommended.
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 and should consider the expansion potential of the on-site soils. Cracking and offsets at joints are likely; 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 6 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
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principal foundation elements should be sealed and drained; this is also important if they are near retaining wall backfills.
Flatwork elements should be a minimum 5-inches thick (actual) and reinforced with No. 3 bars
18-inches on center both ways. Subgrade soils should be pre-soaked to 130 percent of optimum
moisture to a depth of 18-inches and geotechnically approved prior to placement of concrete.
Maintaining the graded moisture content and preventing desiccation of the subgrade soils
through periodic watering of the exposed soils is recommended.
Concrete Construction Components in Contact with Soil
The on-site soils have a low soluble sulfate content based on the results of our laboratory testing, which indicated less than 0.10 percent soluble sulfate. Ordinary Type II cement is,
therefore, anticipated to be suitable for concrete in contact with the subgrade soils. Permanent
caisson wall foundations should use Type V cement. A minimum design strength of 4,500 psi
and water to cement ratio of 0.45 maximum should be used for added flooring and basement
wall moisture considerations. 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. The sulfate testing is presented in the attached Appendix C, Laboratory
Test Results. Additional testing should be done during grading to confirm preliminary test
results. All imported soils should be tested for sulfate content prior to hauling them to the
property.
Metal Construction Components in Contact with Soil
Corrosivity testing was performed as part of our investigation. Test results indicate a severe
potential for corrosion (Resistivity= 2,680 Ohm-cm when saturated). 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. The corrosivity/ chemical testing
results are presented in the attached Appendix C, Laboratory Test Results.
Foundation Excavations
All excavations should be observed by the Geotechnical Engineer prior to placement of forms,
reinforcement, and concrete for verification of conformance with the intention of these recommendations. All excavations should be trimmed neat, level, and square. All loose or
sloughed material should be removed prior to the placement of concrete. Materials from footing
excavations should not be spread in house slab-on-grade areas unless compacted and tested.
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Surface and Subsurface Drainage
1. 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 structures in a non-erosive manner as specified by the
project Civil Engineer or Landscape Architect. Proper interception and disposal of on-site
surface discharge is presumed to be a matter of civil engineering or landscape
architectural design.
2. Drainage and Drainage Devices
The performance of the planned foundation and improvements is dependent upon
maintaining adequate surface drainage both during and after construction. The ground
surface around foundations and improvements should be graded so that surface water
will not collect and pond. The impact of heavy irrigation can artificially create perched
water conditions. This may result in seepage or shallow groundwater conditions where previously none existed.
Attention to surface drainage and controlled irrigation will significantly reduce the
potential for future problems related to water infiltration. Irrigation should be well controlled and minimized. Seasonal adjustments should be made to prevent excessive
watering.
Sources of uncontrolled water, such as leaky water pipes or drains, should be repaired if
identified.
The Owner should be aware of the potential problems that could develop when drainage
is altered through construction of retaining walls, paved walkways, utility installations or
other various improvements. Ponded water, incorrect drainage, leaky irrigation systems,
overwatering or other conditions that could lead to unwanted groundwater infiltration
must be avoided.
Area drains should be installed in all planter and landscape areas. Planter surfaces
should be sloped away from building areas in accordance with Code requirements. Roof drainage should be tight-lined into the area drain system or carried to outlets away from
building foundations. Planters should not be allowed adjacent to foundations unless they
are lined with a bottom barrier installed with a minimum 5 percent gradient away from foundations.
Irrigation water should be controlled for the landscape areas in a way that maintains
uniform moisture conditions around and below the building slab and footings. Changes in exterior moisture will promote heave and desiccation in the soil supporting
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foundations and must, therefore, be avoided. Installation of concrete patios and walkways adjacent to the building is recommended due to the potentially expansive on-
site soil conditions.
3. Infiltration
Concentrated water infiltration into the on-site near surface soils is not practical or
advisable due to possible low permeability rates in the fine-grained, diatomaceous soils
encountered during our field investigation. It is important to not purposely introduce site
water into the gravel zones along basement walls, retaining walls or into slope areas.
BMPs for water quality requirements should be designed by the Civil Engineer. Filtration
of water will be required prior to outlet into the storm drain. Surface and subsurface drainage should be directed toward approved outlets.
Foundation and Grading Plan Review
The undersigned should review final foundation and grading 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. The R
McCarthy Consulting, Inc. (RMC) 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 RMC has reviewed the entire system of which the item is a component.
RMC shall not be responsible for any deviation from the Contract Documents not brought to our
attention in writing by the Contractor. RMC 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 Grading
Guidelines. It is the Owner’s and Contractor’s responsibility to inform Subcontractors of these
requirements and to notify R McCarthy Consulting, Inc. when backfill placement is to begin. It has been our experience that trench backfill requirements are rigorously enforced by the local
agencies.
The on-site soils are suitable for use as trench backfill. On-site soils may be difficult to mix and compact to a uniform condition. The use of imported backfill is sometimes more efficient as an
option. 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.
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If utility contractors indicate that it is undesirable to use compaction equipment in close proximity to a buried conduit, we recommend the utilization of lightweight mechanical
equipment and/or shading of the conduit with clean granular material, which could be
thoroughly jetted in place above the conduit prior to initiating mechanical compaction
procedures. Bedding materials should have a sand equivalent not less than 30. Other methods
of utility trench compaction may also be appropriate as approved by the Geotechnical Engineer
at the time of construction.
The walls of temporary construction trenches are expected to be stable when cut into fill soils,
with only minor sloughing, provided the total depth does not exceed about 4 feet. Shoring of
excavation walls or flattening of slopes may be required, if greater depths are necessary. All
work associated with trench shoring must conform to the State of California Safety Code. The depth of the site utilities is unknown at this time. Excavation exceeding 5 feet below site grades
should be reviewed by the Geotechnical Consultant to provide recommendations prior to
digging.
Trenches should be located so as not to impair the bearing capacity or cause settlement under
foundations. As a guide, trenches subparallel to foundations should be clear of a 45-degree
plane extending outward and downward from the edge of the foundations.
Pre-Grade Meeting
A pre-job conference should be held with a representative of the Owner, Contractor, Architect, Civil Engineer, Geotechnical Engineer, and Building Official prior to commencement of
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 RMC 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 RMC 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.
PA2022-0148
July 12, 2022 File No: 8634-00
Report No: R1-8634
Page: 26
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150 Newport Beach, CA 92660
RMC shall not supervise, direct, or control the Contractor’s work. RMC 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.
RMC 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.
RMC 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 Contract 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;
• to observe the bottom of removals for all excavations for the building pad grading,
trenching, swimming pool, spa, exterior site improvements, etc.;
• to observe side cut excavations for shoring, retaining walls, swimming pool, spa,
trenches, etc.;
• to test for proper moisture content and proper degree of compaction of fill;
• during CIDH Pile/Caisson drilling, if used for shoring and/or deepened foundation
support;
• to check that foundation excavations are clean and founded in competent material;
• prior to and after pre-soaking of the slab subgrade soils, if necessary;
• to check the slab subgrade materials prior to placing the gravel, vapor barrier and
concrete;
• to check retaining wall subdrain installation when the pipe is exposed and before it is
covered by the gravel and fabric; and again after the gravel and fabric have been
placed;
• to test and observe placement of wall backfill materials;
• to test and observe placement of trench backfill materials;
• to test and observe patio, pool deck 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 and Code requirements at the time of the actual construction. The 2019 CBC requires continuous verification and testing during placement of fill materials and
during Pile/Caisson drilling.
PA2022-0148
July 12, 2022 File No: 8634-00
Report No: R1-8634
Page: 27
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150 Newport Beach, CA 92660
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.
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
brought to the attention of the Architect and Engineer for the project and incorporated into the
plans, and the necessary steps are taken to see that the Contractor and Subcontractors carry out such recommendations in the field.
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 3-31-24
Date Signed: 07/12/2022
PA2022-0148
July 12, 2022 File No: 8634-00
Report No: R1-8634
Page: 28
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150 Newport Beach, CA 92660
Accompanying Illustrations and Appendices
Figure 1 - Geotechnical Plot Plan
Figure 2 - Geotechnical Cross Section A-A’
Figure 3 - Geotechnical Cross Section B-B’
Figure 4 - Location Map
Figure 5 - Regional Geology
Figure 6 - Fault Map
Figure 7 - Geologic Hazard Map
Figure 8 - Hazard Map
Figure 9 - Aerial Hazard Map
Appendix A - References
Appendix B - Field Exploration Figures B-1 through B-6
Supporting Documents from Adjoining Lots
Appendix C - Laboratory Testing
Figure C-1 through C-5 Appendix D - Standard Grading Guidelines
Appendix E - Seismicity Data
Appendix F - Hillside Maintenance
PA2022-0148
Af/TmB-1B-2B-3CGB-4AA'BB'CGB-5Tm at 2'Tm at 19.5'HA-1HA-2Af/Qls/Tm????Figure 1 - Geotechnical Plot PlanBase map source: Topographic Map for 2516 & 2518 Bayside Drive, Newport Beach, CA,by Apex Land Surveying Inc., dated 1/22/2018.EXPLANATIONEstimated Location of Exploratory BoringArtificial FillLandslide DebrisMonterey FormationCoast Geotechnical, 6-13-05Coast Geotechnical, 3-14-06AfTmB-3020SCALE, FEET402516 & 2518 Bayside DriveNewport Beach, CAFile: 8634-00 July 2022CGB-4CGB-5B'Geotechnical Cross SectionBDAHLIA
AVENUE
ALLEY
HA-2QlsPA2022-0148
A304050607080Elevation in Feet
Elevation in Feet304050 607080A'PLPLN40°ET.D. 26'B-1(Proj. 13' SE)AfTmWood WallStack Block WallExisting StructureProposed Wood DeckProposed StructureWood Deck407 Dahlia Avenue2516 Bayside DriveT.D. 9.5'HA-1(Proj. 11' SE)???Variable Bedding Attitudes,Bedrock Folded 22°-60° Into SlopeFigure 2 - Geotechnical Cross Section A-A'Notes:1. All elevations estimated; figure is idealized.2. Actual profiles may vary significantly; based on topographic and geologic interpretation.3. Limited elevation control at 407 Dahlia Avenue.4. Bedrock bedding attitudes from Coast Geotechnical, June 2005.IDEALIZED PROFILE2516 & 2518 Bayside Drive Newport Beach, CAFile: 8634-00 July 2022AfTmT.D. 26'Artificial FillMonterey FormationGeologic ContactB-1?EXPLANATIONEstimated Location ofExploratory BoringT.D. 9.5'HA-1010Horizontal and Vertical Scale (feet)20PA2022-0148
B304050607080Elevation in Feet
Elevation in Feet304050 607080B'PLPLN40°ET.D. 20.5'T.D. 13'B-3(Proj. 13' NW)B-2(Proj. 17' SE)??AfExisting StructureProposed Structure2518 Bayside Drive405 Dahlia Avenue????CG-TP-2CG-TP-3TmTmT.D. 5.5'HA-2(Proj. 40' NW)Variable BeddingAttitudes, Bedrock FoldedFigure 3 - Geotechnical Cross Section B-B'2516 & 2518 Bayside Drive Newport Beach, CAFile: 8634-00 July 2022010Horizontal and Vertical Scale (feet)20AfTmT.D. 20.5'Artificial FillMonterey FormationGeologic ContactB-3?EXPLANATIONEstimated Location ofExploratory BoringCoast GeotechnicalTest PitNotes:1. All elevations estimated; figure is idealized.2. Actual profiles may vary significantly; based on topographic and geologic interpretation.3. Limited elevation control at 405 Dahlia Avenue.4. Bedrock bedding attitudes from Coast Geotechnical, July 2003.T.D. 5.5'HA-2IDEALIZED PROFILECG-TP-3PA2022-0148
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:0 400200
SITE:
2516 and 2518 Bayside Drive
FILE NO: 8634-00 JULY 2022 FIGURE 4 - LOCATION MAP
PA2022-0148
Figure 5 - Regional Geology
2516 & 2518 Bayside Drive Newport Beach, CAFile: 8634-00 July 2022
0 2000
SCALE, FEET
4000
SITE2516 & 2518 Bayside Avenue
Pacific Ocean
Base map source: Portion of: PRELIMINARY DIGITAL GEOLOGICAL MAP OF THE 30’ X 60’SANTA ANA QUADRANGLE, SOUTHERN CALIFORNIA, VERSION 2.0U.S. Geological Survey, Open File Report 99-172Compiled by Douglas M. Morton, Kelly R. Bovard, and Rachel M. Alvarez 2004
PA2022-0148
Figure 6 - Fault Location Map02SCALE, MILES1340SCALE, KILOMETERS1562 3 456 7 8 9 102516 and 2518 Bayside Avenue Newport Beach, CAFile: 8634-00 July 2022SITE2516 and 2518 Bayside AvenuePA2022-0148
Figure 7 - Geological Hazards Map
2516 & 2518 Bayside Drive Newport Beach, CAFile: 8634-00 July 2022
0 2000
SCALE, FEET
4000
Pacific Ocean
Base map source: California Department of Conservation,Division of Mines and Geology,
Newport Beach Quadrangle
Seismic Hazard Zone Report for the Newport Beach 7.5-MinuteQuadrangle, Orange County, California. California Geological
Survey, Seismic Hazard Zone Report 03.Liquefaction Released: April 17, 1997Landslide Released: April 15, 1998
LIQUEFACTION
EARTHQUAKE-INDUCED LANDSLIDES
Areas where historic occurrence of liquefaction, or local geological, geotechnical andgroundwater conditions indicate a potential for permanent ground displacements such thatmitigation as defined in Public Resources Code Section 2693(c) would be required.
Areas where previous occurrence of landslide movement, or local topographic, geological,geotechnical and subsurface water conditions indicate a potential for permanent grounddisplacements such that mitigation as defined in Public Resources Code Section 2693(c)would be required.
EXPLANATION
SITE2516 & 2518 Bayside Avenue
PA2022-0148
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:0 833417
SITE:
2516 and 2518 Bayside Drive
FIGURE 8 - HAZARDS MAPJULY 2022 FILE NO: 8634-00
Liquefaction
Hazard Zone
Landslide
Hazard Zone
PA2022-0148
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:
7/11/2022
0 8040
FILE NO: 8634-00 JULY 2022 FIGURE 9 - AERIAL HAZARD MAP
Landslide
Hazard Zone
PA2022-0148
APPENDIX A
REFERENCES
PA2022-0148
APPENDIX A
REFERENCES
(2516 and 2518 Bayside Drive)
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
1. Apex Land Surveying, 2018, “Topographic Map, 2516 and 2518 Bayside Drive, Corona
del Mar, CA, 92625” JN: 18003, 1”-8’, January 22. 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. Brandon Architects, “Dahleh Residence, 2516/2518 Bayside Dr., Corona del Mar, CA
92625,” 1/8” = 1/-0”, undated.
5. California Building Code, 2019 Edition (CBC 2019). 6. California Division of Mines and Geology, 1997/1998, “Seismic Hazards Zones Map,
Newport Beach Quadrangle,” April 17, 1997 and April 15, 1998.
7. California Divisions of Mines and Geology, 2008, “Guidelines for Evaluating and
Mitigating Seismic Hazards in California,” Special Publication 117A. 8. Coast Geotechnical, Inc., 2006, “Addendum Report for 2514 Bayside Drive, Corona del
Mar, California,” W.O. 279205, March 14.
9. Coast Geotechnical, Inc., 2005, “Site Wall Plan Review and Update of Geotechnical Report, Proposed Residence, 403 & 405 Dahlia Avenue, Newport Beach, California,”
W.O. 225603, October 7.
10. Coast Geotechnical, Inc., 2005, “Revised Response to Geotechnical Review, Analysis of
Proposed Construction Cut, 405 Dahlia Avenue, Newport Beach, California,” July 19.
11. Coast Geotechnical, Inc., 2005, “Response to Geotechnical Review, Analysis of Proposed
Construction Cut, 405 Dahlia Avenue, Newport Beach, California,” W.O. 225603, July 12.
12. Coast Geotechnical, Inc., 2005, “Response to Request for Geotechnical Opinion,
Proposed Construction Cut, 405 Dahlia Avenue, Newport Beach, California,” W.O.
225603, June 17.
13. Coast Geotechnical, Inc., 2005, “Geotechnical and Geologic Investigation of Proposed
Residential Development at 2514 and 2517 Bayside Drive, Newport Beach, California,” W.O. 279205-01, June 13.
14. Coast Geotechnical, Inc., 2004, “Addendum Report of Current Site Conditions, Proposed
Residence, 405 Dahlia Avenue, Newport Beach, California,” W.O. 225603, June 18.
15. Coast Geotechnical, Inc., 2004, “Temporary Excavation and Retaining Wall Installation,
Proposed Residence, 405 Dahlia Avenue, Newport Beach, California,” W.O. 225603,
February 16.
16. Coast Geotechnical, Inc., 2003, “Geotechnical and Geologic Investigation for New Residence at 405 Dahlia Avenue, Corona del Mar, California,” W.O. 225603, July 17.
17. David A. Purkis, PE, 2005, “Response to Residential Site Retaining Wall Corrections-
Recheck 1 – Permanent Shoring + Shotcrete Wall; City of Newport Beach Building
Department dated December 12, 2005 for 405 Dahlia, Newport Beach, California,”
Project No. 05-1804, December 23.
18. Department of the Navy, 1982, NAVFAC DM-7.1, Soil Mechanics, Design Manual 7.1,
Naval Facilities Engineering Command. 19. 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).
20. 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.
PA2022-0148
APPENDIX A
REFERENCES
(2516 and 2518 Bayside Drive)
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
21. 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,” SCEC, March.
22. Morton and Miller, 1981, Geologic Map of Orange County, CDMG Bulletin 204.
23. 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.
24. 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. 25. 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.
26. 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. 27. R McCarthy Consulting, Inc., 2015, “Geotechnical Investigation, Proposed Residential
Construction, 2201-2209 Bayside Drive, Newport Beach, California,” File No: 8057-00,
Report 20151010-1R, October 26, revised December 16.
28. R McCarthy Consulting, Inc., 2020, “Geotechnical Investigation, Proposed Residential
Construction, Lot 22, Block 433, 440 Fernleaf Avenue, Corona del Mar, California,” File
No: 8343-00, Report No: R1-8343, June 29.
29. Structural Engineers Association of California (SEAOC), 2019, OSHPD Seismic Design
Maps, https://seismicmaps.org/ 30. 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. 31. Terzaghi, Karl, Peck, Ralph B., and Mesri, Ghoamreza, 1996, “Soil Mechanics in
Engineering Practice, Third Edition,” John Wiley & Sons, Inc.
32. 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.
AERIAL PHOTO REFERENCES FOR FLIGHTS REVIEWED IN THIS INVESTIGATION
https://www.ocgis.com/ocpw/historicalimagery/
1. County of Orange, 1931, Aerial Photograph, Irvine Ranch
2. County of Orange, 1938, Aerial Photograph, Orange County
3. County of Orange, 1947, Aerial Photograph, Newport Beach 4. County of Orange, 1953, Aerial Photograph, Orange County
5. County of Orange, 1960, Aerial Photograph, Orange County
6. County of Orange, 1970, Aerial Photograph, Orange County
PA2022-0148
APPENDIX B
FIELD EXPLORATION
PA2022-0148
APPENDIX B FIELD EXPLORATION
(2516 and 2518 Bayside Drive)
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
General
Subsurface conditions were explored by excavating five exploratory borings at the site. Three
hollow-stem auger borings were advanced on February 16, 2022 to depths ranging from 13 to
26 feet. Two hand-auger borings were advanced on April 7, 2022 to depths of 5.5 and 9.5 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 through B-6. 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 were located in the field by pacing from known landmarks. Their
locations as shown are, therefore, within the accuracy of such measurements. The elevations
on the boring logs were determined by interpolation between points on the Apex Land
Surveying, Inc. Topographic Map, Reference 1.
Sample Program
1. Drill Rig - Standard Penetration Tests (SPT) may be 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.
2. Drill Rig - Relatively undisturbed drive samples were obtained by utilizing a 3-inch outside diameter California sampler lined with brass rings, each 1-inch long and
approximately 2.5-inch inside diameter. The sample was driven for a total length of 18-
inches. The number of blows per foot of driving the final 12-inches were recorded on
the boring logs. The hammer weight and drop were as indicated for the SPT. The brass
rings containing the samples were carefully removed while intact from the California
sampler and transferred into a plastic tube and sealed.
3. Hand Augers - Relatively undisturbed drive samples were obtained by utilizing a sampler
lined on the inside with brass rings, each 1-inch long and 2.5-inches outside diameter.
The sample was typically driven for a total length of about 6-inches. The number of
blows per 6-inches of driving were recorded on the boring logs. The slide hammer used
to drive the samples has a weight of 10.3 pounds with effort. The slide hammer drop
height was 18-inches. The hammer weight alone was not sufficient to drive the sample;
additional energy was applied by the drilling operator by thrust force on the hammer
from the topmost position.* The brass rings were removed from the sampler and
transferred into a plastic tube and sealed.
4. Bulk samples representative of subsurface conditions were collected from the
excavations and sealed in plastic bags.
PA2022-0148
APPENDIX B FIELD EXPLORATION
(2516 and 2518 Bayside Drive)
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
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 a depth of 19 feet in
Boring B-3 within the bedrock.
* Note: Based on correlations on similar sites the blow counts with the slide hammer are generally about 1/3 of the blow count energy of the SPT test; and 1/2 of the blow count of the Cal Sampler. Sample blow counts can be used
as an indicator of soil density. Blow counts may be affected by various additional factors including soil type, moisture
content and/or presence of rocks at the sample level.
PA2022-0148
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
PA2022-0148
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
ML
BORING NO: B-1
FILE NO: 8634-00 FIGURE B-2
EQUIPMENT: 6.5” diameter hollow stem auger, Fraste Rig
SURFACE ELEVATION: 58' +/-BY: GM
Total Depth: 26 feet
No groundwater
SITE LOCATION: 2516 and 2518 Bayside DriveFront lawn, left sideDATE: 2-16-22
Only cap first letter of sentence.
Color, MATERIAL TYPE, moisture, stiffness, density, fineness, all other descriptions
112334
71412
38
50___6”
Upper 2”: Grass lawn
ARTIFICIAL FILL (Af): At 1’ - 4’: Tan to yellow brown sandy
SILT, moist, compacted, rock fragments, diatomaceous
D1 at 4’: Tan brown silty SAND/ sandy SILT, moist, compacted/medium dense, diatomaceous silt layers,
sandstone fragments
SPT1 at 6’: Yellow to gray brown clayey to silty SAND, moist, compacted/medium dense, rock fragments
BEDROCK - MONTEREY FORMATION (Tm):
D2 at 9’: Olive to orange brown SILTSTONE, moist, very stiff,
slightly weathered, diatoms
D3 at 12’: Pale gray SILTSTONE, moist, hard, iron oxidation
staining, siliceous, diatoms
SPT2 at 15’: Pale gray SILTSTONE, moist, very stiff, siliceous, mica flakes, diatoms
D4 at 20’: Olive to pale gray SILTSTONE, moist, hard,
siliceous, mica deposits, iron oxidation staining, diatoms
SPT3 at 25’: White gray to yellow brown SILTSTONE, moist, hard, iron oxidation staining, diatoms
SM/ML
111219
323535
313640
SM/SC
151215
17.2
18.0
28.4
28.9
30.8
36.3
31.0
88
79
75
79
Max Dry Density(99.0 pcf, 22.5 %)Expansion Index
(EI = 56)Chemical Tests
Consolidation Test
Direct Shear(C = 1525 psf, phi = 38 deg.)
PA2022-0148
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
SM
BORING NO: B-2
FILE NO: 8634-00 FIGURE B-3
EQUIPMENT: 6.5” diameter hollow stem auger, Fraste Rig
SURFACE ELEVATION: 59' +/-BY: GM
Total Depth: 13 feet
No groundwater
SITE LOCATION: 2516 and 2518 Bayside DriveFront lawn, right side
D2 at 12’: Red brown SANDSTONE, moist, hard
DATE: 2-16-22
Only cap first letter of sentence.
Color, MATERIAL TYPE, moisture, stiffness, density, fineness, all other descriptions
Consolidation Test 5516
434
30
50___5”
Upper 2”: Grass lawn
ARTIFICIAL FILL (Af): At 1’ - 3’: Tan to yellow brown silty SAND, moist, compacted, rock fragments, cement fragments
SPT1 at 3’: Medium brown silty to clayey SAND, moist, loose, bedrock fragments
D1 at 6’: Medium brown silty SAND, moist, compacted/
medium dense, scattered rock fragments of variable
composition, siltstone fragments at tip of sampler
BEDROCK - MONTEREY FORMATION (Tm):
SPT2 at 9’: White-gray SILTSTONE, moist, very stiff,
weathered
SM
SM/
SC
121410
19.9
23.6
18.4
9.2 130
67
PA2022-0148
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
BORING NO: B-3
FILE NO: 8634-00 FIGURE B-4
EQUIPMENT: 6.5” diameter hollow stem auger, Fraste Rig
SURFACE ELEVATION: 58' +/- BY: GM
Total Depth: 20.5 feet
Water at 19 feet
SITE LOCATION: 2516 and 2518 Bayside DriveDriveway, right side of structure
SPT1 at 6’: Red brown silty SAND, moist, medium dense, scattered rock fragments, some clay layers
SPT2 at 12’: Medium to olive brown silty SAND, moist, medium dense, abundant weathered siltstone fragments
SPT3 at 19’: Dark olive gray SILTSTONE, wet, medium stiff, disturbed/significantly weathered, diatoms
D1 at 3’: Red brown silty SAND, moist, medium dense, scattered rock fragments, large SILTSTONE fragment at tip of sampler
D2 at 9’: Medium brown sandy SILT, moist, stiff, abundant
siltstone bedrock fragments, slight clayey
D3 at 15’: Olive to yellow brown SILTSTONE, moist, stiff, disturbed/weathered, diatoms
DATE: 2-16-22
Only cap first letter of sentence.
Color, MATERIAL TYPE, moisture, stiffness, density, fineness, all other descriptions
51014
81010
647
Upper 8”: Concrete
ARTIFICIAL FILL (Af): At 1’ - 3’: Tan to red brown silty SAND, moist, medium dense, abundant rock fragments
BEDROCK - MONTEREY FORMATION (Tm)/ Possible landslide
debris (Qls):
575
589
244
13.2
8.0
31.2
31.8
35.1
41.2
99
71
73
Direct Shear(C = 275 psf, phi =
46 deg.)
PA2022-0148
DEPTHUSCSBLOW COUNTIN-PLACE SAMPLEBAG SAMPLEMOISTURE (%)DRY DENSITY (PCF)MATERIAL DESCRIPTION NOTES DEPTHLOG OF BORING FIGURE B-5
R MCCARTHY CONSULTING, INC.
5
10
15
20
25
5
10
15
20
25
ML
BORING NO: HA-1
FILE NO: 8634-00
EQUIPMENT: 4” Diam Hand Auger
SURFACE ELEVATION: 74' +/-BY: GM
Total Depth: 9.5 feet
No groundwater
No caving
SITE LOCATION: 2516 and 2518 Bayside DriveRear retaining wallDATE: 4-7-22
Only cap first letter of sentence.
Color, MATERIAL TYPE, moisture, stiffness, density, fineness, all other descriptions 12
ARTIFICIAL FILL (Af): Upper 6 inches dark brown, sandy SILT, dry, soft, also contains rock fragmentsD1 @ 1’: Dark brown sandy SILT, moist, medium stiff,
abundant rock fragments, disturbed
D2 @ 3’: Yellow brown sandy SILT, moist, medium stiff, bedrock fragments, disturbed
D3 at 6’: Olive to yellow brown sandy SILT, moist, stiff,
bedrock fragments, mottled, diatomaceous
D4 at 9': Olive to yellow sandy SILT, moist, stiff, bedrock
fragments, mottled
ML
ML
21.1
23.3
74
74
21
26
30
ML
16.6
28.4
PA2022-0148
DEPTHUSCSBLOW COUNTIN-PLACE SAMPLEBAG SAMPLEMOISTURE (%)DRY DENSITY (PCF)MATERIAL DESCRIPTION NOTES DEPTHLOG OF BORING FIGURE B-6
R MCCARTHY CONSULTING, INC.
5
10
15
20
25
5
10
15
20
25
SM
BORING NO: HA-2
FILE NO: 8634-00
EQUIPMENT: 4” Diam Hand Auger
SURFACE ELEVATION: 63' +/-BY: GM
Total Depth: 5.5 feet
No groundwater
No caving
SITE LOCATION: 2516 and 2518 Bayside DriveRear retaining wallDATE: 4-7-22
Only cap first letter of sentence.
Color, MATERIAL TYPE, moisture, stiffness, density, fineness, all other descriptions
50
/2"
ARTIFICIAL FILL (Af): Upper 6 inches : Olive brown silty SAND, dry, loose, abundant rock fragments
D1 at 2’: Olive brown, silty SAND, moist, medium dense,
rock fragments, sample disturbed
D2 at 3’: Olive brown, silty SAND, moist, medium dense, gravels and pebbles, sample disturbed
MONTEREY FORMATION (Tm): D3 at 5': Yellow brown,
SILTSTONE, moist, hard, fractured, cherty, poor recovery
SM 14.2
16.6
12.1
30
32
SM
PA2022-0148
APPENDIX C
LABORATORY TESTING
PA2022-0148
APPENDIX C LABORATORY TESTING
(2516 & 2518 Bayside Drive)
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. Testing was supplemented with chemical testing performed by HDR,
Inc.
Soils were classified visually and per the results of laboratory testing according to ASTM D2487,
the Unified Soil Classification System (USCS). The field moisture content and dry densities of the soils encountered were determined by performing laboratory tests on the collected samples. The
results of the moisture tests, density determinations and soil classifications are shown on the
Boring Logs, Figures B-2 and B-6.
Maximum Density
The maximum dry density and optimum moisture content relationships were determined for
representative samples of the on-site soil. 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
Expansion Index Test
Expansion index tests were performed in accordance with ASTM D4829. The results are summarized in Table C-2 below.
TABLE C-2
RESULTS OF EXPANSION INDEX
ASTM D4829
Test Location Soil
Classification Soil Description Maximum Dry
Density (pcf)
Optimum
Moisture
Content %
B-1 @ 0-5’ CL Brown Sandy CLAY 99.0 22.5
Test
Location
Soil
Classification
Expansion
Index
Expansion
Potential
Moisture
Content %
Saturation
%
B-1 @ 0-5’ CL 56 Medium 18.4 Initial
35.1 Final
49 Initial
92 Final
PA2022-0148
APPENDIX C LABORATORY TESTING
(2516 & 2518 Bayside Drive)
R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
Direct Shear – Relatively Undisturbed
Direct shear tests were performed on selected relatively undisturbed samples which were saturated under a surcharge equal to the applied normal force during testing. The apparatus used
is in conformance with the requirements outlined in ASTM D3080. The test specimens,
approximately 2.5-inches in diameter and 1-inch in height, were subjected to simple shear along a
plane at mid-height after allowing time for pore pressure dissipation prior to application of shearing
force. The samples were tested under various normal loads, a different specimen being used for
each normal load. The samples were sheared at a constant rate of strain of 0.005-inches per
minute. Shearing of the specimens was continued until the shear stress became essentially
constant or until a deformation of approximately 10 percent of the original diameter was reached.
The peak and ultimate shear stress values were plotted versus applied normal stress, and a best-fit
straight line through the plotted points was determined to arrive at the cohesion and the angle of
internal friction parameters of the soil samples. The direct shear test results are presented in Figures C-2 and C-3.
Consolidation Test
Consolidation tests were performed on selected relatively undisturbed samples in accordance
with procedures outlined in ASTM: D2435. Samples were placed in a consolidometer and loads
were applied incrementally in geometric progression. The samples (2.5-inches in diameter and
1-inch in height) were permitted to consolidate under each load increment until primary
consolidation was essentially complete. The percent consolidation for each load cycle was
recorded as the ratio of the amount of vertical compression to the original 1-inch
height. Hydroconsolidation (collapse) and expansion characteristics were also evaluated by
monitoring the change in volume with the addition of water while the specimen was confined
under an in-situ constant normal stress. The consolidation test results are graphically presented
on Figures C-4 and C-5.
Sulfate Test
Sulfate test results indicated negligible soluble sulfates as shown in Table C-3 below:
TABLE C-3
RESULTS OF SULFATE TEST
Test
Location
Soil
Classification
Soluble Sulfates
(ppm) Exposure Class
B-1 @ 0-5’ CL 39 SO (Low)
PA2022-0148
APPENDIX C LABORATORY TESTING
(2516 & 2518 Bayside Drive)
R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
Chemical Testing
A series of corrosivity tests were performed on the sample B-1 @ 0-5 feet. These tests were
performed by HDR and the test results are attached. The test results are as presented below in
Table C-4.
Table C-4
CHEMICAL TESTING
Test
Location Soil
Classification pH
Soluble Sulfates
(mg/kg)
ASTM D4327
Soluble
Chlorides (mg/kg)
ASTM D4327
Min. Resistivity
(ohm-cm)
ASTM G187
B-1 @ 0-5’ CL 8.7 39 13 2,680
PA2022-0148
Date:C-1
Sample Identification B-1 @ 0-5'
MAXIMUM DENSITY & OPTIMUM MOISTURE CONTENT DETERMINATION
File No.: 8634-00 May - 2022 Figure:
Sample Description Brown Sandy CLAY w/rock fragments
Maximum Dry Density (pcf)99.0
Optimum Moisture Content (%)22.5
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
PA2022-0148
Dry Density (pcf)
Angle of Friction -
degrees
(Ultimate)
25.080.1
Moisture Content
(%) 50.7
B-1 @ 20'
Characteristics
Cohesion - psf
(Peak)1525
Sample Identification
Shear Strength
Angle of Friction -
degrees (Peak)
Cohesion - psf
(Ultimate)1400
38.0
C-2Figure No.:May - 2022
Rate of Shear 0.005 in/min Sample Type In-Situ
Date:8634-00
DIRECT SHEAR TEST
File No.:
0
1000
2000
3000
4000
5000
6000
0 1000 2000 3000 4000 5000 6000Shearing Stress (psf)Normal Stress (psf)
PA2022-0148
Dry Density (pcf)
Angle of Friction -
degrees
(Ultimate)
46.095.4
Moisture Content
(%) 28.6
B-3 @ 3'
Characteristics
Cohesion - psf
(Peak)275
Sample Identification
Shear Strength
Angle of Friction -
degrees (Peak)
Cohesion - psf
(Ultimate)125
46.0
C-3Figure No.:May - 2022
Rate of Shear 0.005 in/min Sample Type In-Situ
Date:8634-00
DIRECT SHEAR TEST
File No.:
0
1000
2000
3000
4000
5000
6000
0 1000 2000 3000 4000 5000 6000Shearing Stress (psf)Normal Stress (psf)
PA2022-0148
C-4
Initial
Final
96.1
103.8
Initial
Final
17.2
31.2 Water added at 800 psf
B-1 @ 4Sample Identification
Dry Density (pcf) Moisture Content (%) Testing
Figure No.:May 2022Date:File No.: 8634-00
CONSOLIDATION TEST RESULTS
-2.000
0.000
2.000
4.000
6.000
8.000
10.000
12.000
14.000
16.000
18.000
20.000
22.000
24.000
0.1 1 10 100Strain (%)Normal Pressure (ksf)CompressionExpansionPA2022-0148
C-5
Initial
Final
92.4
101.4
Initial
Final
23.9
31.5 Water added at 800 psf
B-2 @ 6'Sample Identification
Dry Density (pcf) Moisture Content (%) Testing
Figure No.:May 2022Date:File No.: 8634-00
CONSOLIDATION TEST RESULTS
-2.000
0.000
2.000
4.000
6.000
8.000
10.000
12.000
14.000
16.000
18.000
20.000
22.000
24.000
0.1 1 10 100Strain (%)Normal Pressure (ksf)CompressionExpansionPA2022-0148
DATE:
ATTENTION: Rob McCarthy
TO:
SUBJECT:
COMMENTS:
James T. Keegan, MD
Corrosion and Lab Services Section Manager
TRANSMITTAL LETTER
8634-00 - 2516-2518 Batside Drive
Enclosed are the results for the subject project.
23 Corporate Plaza, Suite 150
Laboratory Test Data
Newport Beach, CA 92660
February 25, 2022
Your #8634-00, HDR Lab #22-0206LAB
R McCarthy Consulting, Inc.
431 West Baseline Road ∙ Claremont, CA 91711
Phone: 909.962.5485 ∙ Fax: 909.626.3316
PA2022-0148
Sample ID
B-1 @ 0-5'
Resistivity Units
as-received ohm-cm 12,000
saturated ohm-cm 2,680
pH 8.7
Electrical
Conductivity mS/cm 0.10
Chemical Analyses
Cations
calcium Ca2+mg/kg 58
magnesium Mg2+mg/kg ND
sodium Na1+mg/kg 69
potassium K1+mg/kg 9.7
ammonium NH41+mg/kg ND
Anions
carbonate CO32-mg/kg 42
bicarbonate HCO31-mg/kg 88
fluoride F1-mg/kg 9.7
chloride Cl1-mg/kg 13
sulfate SO42-mg/kg 39
nitrate NO31-mg/kg 2.8
phosphate PO43-mg/kg 1.5
Other Tests
sulfide S2-qual na
Redox mV na
Resistivity per ASTM G187, pH per ASTM G51, Cations per ASTM D6919, Anions per ASTM D4327, and Alkalinity per APHA 2320-B.
Electrical conductivity in millisiemens/cm and chemical analyses were made on a 1:5 soil-to-water extract.
mg/kg = milligrams per kilogram (parts per million) of dry soil.
Redox = oxidation-reduction potential in millivolts
ND = not detected
na = not analyzed
Table 1 - Laboratory Tests on Soil Samples
8634-00 - 2516-2518 Batside Drive
Your #8634-00, HDR Lab #22-0206LAB
25-Feb-22
R McCarthy Consulting, Inc.
431 West Baseline Road ∙ Claremont, CA 91711
Phone: 909.962.5485 ∙ Fax: 909.626.3316 Page 2 of 2
PA2022-0148
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
APPENDIX D
STANDARD GRADING GUIDELINES
PA2022-0148
APPENDIX D
STANDARD GRADING GUIDELINES
(2516 and 2518 Bayside Avenue)
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., (RMC), 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
PA2022-0148
APPENDIX D
STANDARD GRADING GUIDELINES
(2516 and 2518 Bayside Avenue)
R McCarthy Consulting, Inc. 23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
placed so that they are completely surrounded by compacted fines; no nesting of rocks shall be
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 D1557 (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 1 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.
PA2022-0148
APPENDIX D
STANDARD GRADING GUIDELINES
(2516 and 2518 Bayside Avenue)
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.
PA2022-0148
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150 Newport Beach, CA 92660
Phone 949-629-2539
APPENDIX E
SEISMICITY DATA
PA2022-0148
ASCE 7 Hazards Report
Address:
2516 Bayside Dr
Corona Del Mar, California
92625
Standard:ASCE/SEI 7-16
Risk Category:II
Soil Class:D - Default (see
Section 11.4.3)
Elevation:68.55 ft (NAVD 88)
Latitude:
Longitude:
33.599728
-117.876855
Page 1 of 3https://asce7hazardtool.online/Thu Apr 07 2022
PA2022-0148
SS : 1.361
S1 : 0.483
Fa : 1.2
Fv : N/A
SMS : 1.634
SM1 : N/A
SDS : 1.089
SD1 : N/A
TL : 8
PGA : 0.595
PGA M : 0.714
FPGA : 1.2
Ie : 1
Cv : 1.372
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.
Thu Apr 07 2022
Page 2 of 3https://asce7hazardtool.online/Thu Apr 07 2022
Additional Calculations:
SM1 =(FV)(S1)
Fv = 1.817 for S1 = 0.483 g per Table 1613A.2.3(2)
Therefore, SM1 = (1.817)(.483) = 0.878 g
SD1 = (2/3)(SM1) = (2/3)(0.878) = 0.585 g
PA2022-0148
The ASCE 7 Hazard Tool is provided for your convenience, for informational purposes only, and is provided “as is” and without warranties of
any kind. The location data included herein has been obtained from information developed, produced, and maintained by third party providers;
or has been extrapolated from maps incorporated in the ASCE 7 standard. While ASCE has made every effort to use data obtained from
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In using this Tool, you expressly assume all risks associated with your use. Under no circumstances shall ASCE or its officers, directors,
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Page 3 of 3https://asce7hazardtool.online/Thu Apr 07 2022
PA2022-0148
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150 Newport Beach, CA 92660
Phone 949-629-2539
APPENDIX F
HILLSIDE MAINTENANCE
PA2022-0148
APPENDIX F
SUGGESTED GUIDELINES FOR MAINTENANCE OF HILLSIDE PROPERTY
(2516 and 2518 Bayside Avenue)
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
Slopes and Slope Drainage Devices
Maintenance of slopes and drainage devices is important to their long term performance. The
following is a list of suggested procedures provided as a guide for slope maintenance.
1.Drainage Devices Associated with Hillsides
•Graded berms, swales, area drains, and slopes are designed to carry surface water
from pad areas and should not be blocked or destroyed. Water should not be
allowed to pond in pad areas, or overtop and flow onto graded or natural slopes.
•Sources of uncontrolled water, such as leaky water pipes or drains, should be
repaired if identified.
•Devices constructed to drain and protect slopes, including brow ditches, berms,
terrace drains and down drains should be maintained regularly, and in particular,
should not be allowed to clog such that water can flow unchecked over slope faces.
•Subdrain outlets should be maintained to prevent burial or other blockage.
2.Slopes
•Slopes in the southern California area should be planted with appropriate drought-
resistant vegetation as recommended by a landscape architect.
•Rodent activity should be controlled on the slope and within yard areas along the top of
the slope as burrowing may introduce paths for transfer of water into the subsurface
soils and out to the slope face.
Lot and Building Pad Drainage
1.Roof drains should collect water into a tight-lined drainage system of area drains. When
area drain systems are not feasible, roof drain water should be diverted by swales and
sloping ground to approved outlet areas. Where planters or unimproved ground are
located next to building foundations or slab-on-grade construction, roof drain outlets
should be extended at least 3 feet away from the structure. Outlets and infiltration of
roof water next to structures is not acceptable and should be eliminated by drainage
devices.
2.Area drain inlet grates should be properly installed and maintained. The inlets need to
be properly located at lower grade collection points around yard areas. The grate should
be installed low enough to quickly transfer collecting water into the area drain pipe
system. It should also be installed high enough to not be easily buried, silted over or
choked out by vegetation.
3.Drainage inlet grates should be regularly inspected and cleaned/replaced as necessary
to allow free flow of water into the drain system while effectively blocking larger detritus
from entering risers and flow pipes.
4.Area drain pipes should be periodically checked for blockage and cleaned as necessary.
PA2022-0148
APPENDIX F
SUGGESTED GUIDELINES FOR MAINTENANCE OF HILLSIDE PROPERTY
(2516 and 2518 Bayside Avenue)
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
5.Landscape grades should be maintained or improved to allow efficient drainage to
approved surface water outlets and into the storm drain system. Modifications to
designed or existing drainage grades should be made as necessary when ponds of
excess water, standing water, low flows, etc., are noticed. An experienced landscape
contractor or landscape architect should be consulted, if necessary, to provide
recommendations for drainage improvements.
6.As yard improvements are made to existing residential properties, it is common for
unlicensed landscape contractors, laborers or the homeowner to alter the flow patterns
that were designed for site drainage. Such actions however can be harmful to the
property. Adverse infiltration and surface flows may cause damage to foundations,
slabs, concrete hardscape, slopes, neighboring properties, etc., and result in large repair
costs or litigation.
Water Use
1.Irrigation of on-site vegetation should be properly controlled. Excessive watering should
be avoided not only to save water, but also to protect property.
2.Water leaks should be repaired quickly when identified.
3.Broken sprinkler heads, broken pipes, leaks at joints, or other breaches should be
immediately repaired when identified.
PA2022-0148