HomeMy WebLinkAboutPA2022-0155_20220718_Geotechnical Investigation_07-12-22
1000 North Coast Highway Suite 10 Laguna Beach, California 92651 (949) 403-7229 SAgeotechnical.com
July 12, 2022
Project No. 22077-01
To: Holly Jankiewicz
Beachlife Rentals LLC
316 Grand Canal
Newport Beach, California 92662
Attention: Mr. Nate Nicodemus, Christian Rice Architects, Inc.
Subject: Preliminary Geotechnical Investigation for Design and Construction of Proposed New
Residential Structure, 316 Grand Canal, City of Newport Beach, California
At your request, SA Geotechnical, Inc. (SA GEO) has conducted a limited geotechnical investigation for
the proposed new residential construction at 316 Grand Canal, City of Newport Beach, California. The
purpose of this study was to evaluate the geotechnical site conditions in light of the proposed grading and
improvements in order to provide geotechnical recommendations for the project design, grading and
construction. Our evaluation included review of collected geologic, geotechnical engineering, and
seismological reports and maps pertinent to the subject site; a site exploration; geotechnical analysis; and
preparation of this report.
The subject site is located at 316 Grand Canal, City of Newport Beach, California and is legally identified
as Lot 9 of Tract 742, Balboa Island, Assessor Parcel Number (APN) 050-202-05. The site currently
consists of a flat pad that is developed with two residential units and exterior hardscape improvements. The
proposed improvements are anticipated to consist demolition of the existing structures and construction of
a new, three-story residential structure and hardscape improvements.
Based on our findings, we conclude that the proposed project is feasible from a geotechnical viewpoint
provided it is designed and constructed in accordance with the recommendations presented in this report
and any future plan review reports. The primary geotechnical constraints associated with the site are shallow
groundwater, strong ground shaking during seismic events, and the potential for liquefaction and/or
settlement of underlying soils, which will require remedial grading and geo-grid reinforcement to reduce
the hazard potential. Appropriate construction measures and care should be taken to ensure the proposed
construction does not adversely impact the subject site and or adjoining properties.
PA2022-0155
22077-01
July 12, 2022
2 220712_316 Grand Canal, Newport Beach (22077-01)
If you have any questions regarding this report, please contact our office. We appreciate the opportunity to
provide our services.
Respectfully submitted,
SA GEOTECHNICAL, INC.
Peter Anderson, CEG 2596 Reza Saberi, GE 3071
Principal Engineering Geologist Principal Engineer
PA2022-0155
22077-01
July 12, 2022
3 220712_316 Grand Canal, Newport Beach (22077-01)
TABLE OF CONTENTS
EXECUTIVE SUMMARY ...................................................................................................................... 5
1.0 INTRODUCTION ........................................................................................................................... 6
1.1 Introduction and Scope of Services ............................................................................................. 6
1.2 Site Condition and Prior Studies ................................................................................................. 6
1.4 Field Exploration ......................................................................................................................... 7
1.5 Laboratory Testing ...................................................................................................................... 7
2.0 GEOTECHNICAL FINDINGS ....................................................................................................... 8
2.1 Geologic Setting .......................................................................................................................... 8
2.2 Earth Units ................................................................................................................................... 8
2.3 Laboratory Testing ...................................................................................................................... 8
2.4 Groundwater and Surface Water ................................................................................................. 8
2.5 Regional Faulting and Seismicity ................................................................................................ 9
2.6 Slope Stability ............................................................................................................................. 9
2.7 Liquefaction Potential.................................................................................................................. 9
2.8 Settlement and Foundation Considerations ............................................................................... 10
3.0 CONCLUSION AND RECOMMENDATIONS ........................................................................... 11
3.1 General Conclusion and Recommendation ............................................................................... 11
3.2 Site Preparation and Earthwork ................................................................................................. 11
3.2.1 Site Demolition and Clearing .................................................................................................. 11
3.2.2 Protection of Existing Improvements and Utilities ................................................................. 12
3.2.3 Remedial Grading Measures ................................................................................................... 12
3.2.4 Fill Placement ......................................................................................................................... 13
3.3 Seismic Design Parameters ....................................................................................................... 13
3.4 Foundation Design ..................................................................................................................... 14
3.5 Slope Setbacks ........................................................................................................................... 15
3.6 Interior Slab Moisture Mitigation .............................................................................................. 15
3.7 Settlement Potential ................................................................................................................... 15
3.8 Retaining Walls ......................................................................................................................... 16
3.10 Exterior Concrete ....................................................................................................................... 17
3.11 Trench Excavation and Backfill ................................................................................................ 18
3.12 Groundwater .............................................................................................................................. 18
3.13 Stormwater Infiltration .............................................................................................................. 18
3.14 Surface Drainage and Irrigation ................................................................................................ 19
3.15 Review of Future Plans.............................................................................................................. 19
3.16 Observation and Testing during Grading and Construction ...................................................... 20
3.17 Limitations ................................................................................................................................. 20
PA2022-0155
22077-01
July 12, 2022
4 220712_316 Grand Canal, Newport Beach (22077-01)
TABLE OF CONTENTS (Continued)
List of Illustrations
Figure 1 – Site Location and Seismic Hazards Map – Rear of Text
Figure 2 – Regional Geologic Map– Rear of Text
Figure 3 – Regional Fault Map – Rear of Text
Figure 4 – Retaining Wall Drainage Detail – Rear of Text
Appendices
Appendix A – References
Appendix B – CPT and Boring Logs
Appendix C – Laboratory Test Results
Appendix D – Seismicity Data
Appendix E – Liquefaction Analysis
Appendix F – General Earthwork and Grading Specifications
Plates
Plate 1 – Geotechnical Map – Rear of Text
PA2022-0155
22077-01
July 12, 2022
5 220712_316 Grand Canal, Newport Beach (22077-01)
EXECUTIVE SUMMARY
SA GEO reviewed and compiled existing geotechnical data for the subject site and surrounding area
gathered during in-house background research, site visits, as well as from information provided by the
project team and the City of Newport Beach. Prior geotechnical reports prepared for the site and nearby
lots were also reviewed (Appendix A). A limited geotechnical exploration performed by SA GEO included
advancement of one Cone Penetrometer Test (CPT-1) to a maximum depth of 20.7-feet and three hand-
auger borings to a maximum depth of 4.75-feet (Appendix B). Laboratory testing was performed on soil
samples to determine the engineering soil properties (Appendix C).
The proposed improvements are anticipated to consist of demolition of the existing onsite structures and
construction of a new, three-story residential structure. Design finish floor elevations are approximately 2
to 3- feet above existing grades. Hardscape improvements are anticipated to include a concrete driveway,
patio, and walkways. The project is currently in the preliminary design phase. Project plans should be
provided to the geotechnical consultant when they become available to confirm design assumptions
included herein.
The subject property is underlain by artificial fill and native estuarine deposits. The existing fill soils and
estuarine deposits generally consist of damp to saturated sand, silty sand, and sandy clay that are loose near-
surface and medium dense/stiff at depth. Groundwater was encountered during our exploration and by
others (Appendix A) at depths ranging from 3.25 to 4 feet. The primary geotechnical constraints associated
with the site are strong ground shaking during a seismic event, the potential for liquefaction and settlement
of underlying native soils, and shallow groundwater condition. Based on our exploration and analyses, we
estimate approximately 3-inches of vertical settlement due to seismic induced liquefaction.
Fills of 1 to 3+ feet are anticipated to reach design grade and to provide for proper site drainage. Existing
fill and/or weathered/disturbed estuarine deposits are considered unsuitable for structural support of
foundation elements. Thus, remedial removals are recommended to provide uniform compacted fill blanket
and limit future static and seismic settlement potentials. Removals should extend to a minimum depth of
3-feet below existing grades. Where not limited by adjacent structures/properties, the removals should
extend a minimum of 5 feet beyond the limits of the proposed building footprints. Two layers of geogrid
reinforcement (Miragrid 8XT or approved equivalent) should be placed, with the deeper layer placed on
the removal bottom and the second layer placed one foot above the first layer, separated by one foot of
compacted fill. Foundations for all structural elements that are not tolerant to significant movement,
including the proposed residential building, should be supported on a minimum of 3 feet of compacted fill
and two layers of the geogrid discussed herein. New structural foundation elements, are anticipated to be
supported by competent, engineered artificial fill.
Temporary excavations along the project boundaries may be made at a 1:1 inclination to a maximum height
of 3-feet, pending review by the geotechnical consultant. Where spatial constraints limit appropriate
layback of temporary excavations, shoring will be required. Temporary excavations should not be left open
for extended periods of time or during adverse weather conditions. Appropriate construction methods and
care should be taken to ensure the proposed construction does not adversely impact the existing
improvements and/or adjoining properties.
The proposed construction is considered feasible from a geotechnical standpoint provided the
recommendations in this report are properly implemented during design, grading, and construction. 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. The future precise grading, foundation, retaining wall (if any) and landscape plans should
be reviewed by the geotechnical consultant to confirm the actual design conditions and provide updated
recommendations, as needed.
PA2022-0155
22077-01
July 12, 2022
6 220712_316 Grand Canal, Newport Beach (22077-01)
1.0 INTRODUCTION
1.1 Introduction and Scope of Services
At your request, SA Geotechnical, Inc. (SA GEO) has conducted a limited geotechnical exploration for the
proposed new residential construction located at 316 Grand Canal, City of Newport Beach, California
(Figure 1). The purpose of this study was to evaluate the geotechnical site conditions in light of the proposed
improvements in order to provide geotechnical recommendations for the project design, grading and
construction. We have reviewed a topographic map prepared by Bledsoe Giron Engineering & Survey Inc.,
dated March 17, 2022 and a preliminary Site Plan prepared by Christian Rice Architects, Inc., dated May
4, 2022. The topographic map was utilized as the base for the Geotechnical Map (Plate 1).
Our scope of services for this study included the following tasks:
Review of collected geologic, geotechnical engineering and seismological reports and maps pertinent
to the subject site (referenced in Appendix A).
Site reconnaissance to identify the existing site conditions.
Field exploration consisting of advancement of one Cone Penetrometer Test (CPT-1) to a depth of 20.7
feet below ground surface (bgs) and three hand-auger borings (HA-1 through HA-3) to a maximum
depth of 4.75 feet. Boring and CPT logs are included in Appendix B.
Geotechnical evaluation and analysis of the compiled data with respect to the proposed improvements.
Evaluation of faulting, and seismicity in accordance with the 2019 California Building Code (CBC).
Preparation of this report including our findings, conclusions, recommendations, and accompanying
illustrations.
Consultations with the project team.
SA GEO’s expertise and scope of services do not include assessment of potential subsurface environmental
contaminants or environmental health hazards.
1.2 Site Condition and Prior Studies
The subject site is located at 316 Grand Canal, City of Newport Beach, California and is legally identified
as Lot 9 of Tract 742, Balboa Island, Assessor Parcel Number (APN) 050-202-05 (Figure 1). The
approximately 2,175 square foot, rectangular-shaped lot is situated along the west side of Abalone Drive
and east of Grand Canal. The site is currently developed with two separate units, one single story structure
on the western half of the lot, and one two-story structure on the eastern half with a lower-level garage,
both of which are wood-framed residential structures. Exterior hardscape improvements are located along
the perimeter of the lot. Adjacent residential properties are located to the north and south. A concrete sea
wall and waterway/canal are located adjacent and along the western side of the subject site. The lot is
essentially the same elevation as surrounding properties to the north and south, and Abalone Drive.
Maximum grade change across the site is less than 1-foot.
A prior subsurface exploration, preliminary geotechnical report, and report of observation and testing was
prepared by Geo-Etka, Inc. (1994a and 1994b) for the subject site, related to construction of the existing
easterly two-story structure. The exploration included excavation of two 6-inch diameter hand-auger
borings. Laboratory testing was performed on select samples to determine the soil engineering properties.
We have reviewed the boring and laboratory data included in these reports as part of this study. In addition,
we have reviewed the prior geotechnical report for nearby sites (Appendix A).
PA2022-0155
22077-01
July 12, 2022
7 220712_316 Grand Canal, Newport Beach (22077-01)
The existing onsite structures are anticipated to be demolished and removed prior to development of the
proposed new residential improvements.
1.3 Proposed Grading and Improvements
Based on our review of the preliminary Site Plan prepared by Christian Rice Architects, Inc., dated May 4,
2022, we understand that the proposed improvements will include demolition of the existing residential
structures and construction of a new three-story residential structure. Design finish floor elevations are
approximately 2 to 3-feet above existing grades. Hardscape improvements are anticipated to include a
concrete driveway, patio, and walkways.
Design fills are anticipated to be on the order of 1 to 3 feet in order to reach pad grade and provide for
proper site drainage. Existing near-surface soils consist of undocumented fill and weathered/disturbed
estuarine deposits; thus, remedial grading is recommended to provide competent subgrade and reduce
liquefaction hazard potential. Building loads are anticipated to be supported by a structural (mat) slab
constructed over competent fill material.
1.4 Field Exploration
Our field exploration was performed on June 23, 2022 and consisted of advancement of one (1) Cone
Penetrometer Test (CPT-1) to a depth of approximately 20.7 feet (refusal) and three (3) hand-auger borings
(HA-1 through HA-3) to a maximum depth of 4.75 feet. The approximate boring and CPT locations are
shown on Plate 1 (Geotechnical Map). At the completion of our exploration, the CPT was backfilled using
bentonite granules and borings were backfilled using cuttings. Boring and CPT logs are included in
Appendix B.
The borings were used to assess the soil beneath the site and collect bulk samples to determine the
engineering properties.
The CPT uses an integrated electronic cone system which measures and records cone tip resistance, sleeve
friction, and friction ratio parameters at 5-cm depth intervals by advancement of a 1.25-inch-diameter
pointed steel probe that is hydraulically pushed into the ground at a constant rate. CPTs provide a detailed
subsurface profile to allow for assessment of potential liquefaction hazards. CPT data was used in
conjunction with boring and laboratory test data to develop interpretation of the subsurface conditions.
1.5 Laboratory Testing
SA GEO tested representative samples of onsite soils collected during our field exploration to characterize
the engineering properties. Laboratory tests performed on selected bulk soil samples included:
Sieve analysis; and
Soluble sulfate content.
Laboratory tests were conducted in general conformance with applicable ASTM International standards.
The laboratory test results are provided in Appendix C. The prior laboratory testing by others was also
reviewed as part of our study.
PA2022-0155
22077-01
July 12, 2022
8 220712_316 Grand Canal, Newport Beach (22077-01)
2.0 GEOTECHNICAL FINDINGS
2.1 Geologic Setting
The subject site is located on Balboa Island within Newport Bay, south of the Newport Mesa and southwest
of the San Joaquin Hills, within the Peninsular Range geomorphic province of Southern California. The
island is generally underlain by recent marine (estuary) deposits consisting predominately of sand
interlayered with silt and clay. Historic aerial photos and topographic maps suggest that Balboa Island was
formerly an intertidal sand bar and island of the natural Newport Bay area. Bedrock, which compose the
Newport Mesa and northwestern San Joaquin Hills, is believed to underlie the estuarine deposits at depth.
2.2 Earth Units
Review of available geologic maps and reports for the subject site and surrounding area (Appendix A)
indicate that the site is underlain by late Holocene-age estuarine deposits (Qes), identified on the basis of
regional geologic mapping (Figure 2) and the findings of our site exploration. The estuarine deposits are
generally described as sand, silt, and clay with variable amounts of organic matter (USGS, 2006). The
subsurface soils as encountered in our exploration were found to consist predominately of sand and silty
sand with interlayered sandy silt and silty clay. Soils were damp to moist near surface and wet to saturated
below approximately 3 feet. Organic soils and/or peat were not encountered during our exploration. The
onsite borings by others (Geo-Etka, 1994a) for the prior construction generally encountered similar soil and
groundwater conditions.
Although not encountered during our investigation, based on our review of prior reports, we anticipate
approximately 2.5 feet of compacted artificial fill (Af) below the easterly portion of the site, related to
construction of the existing two-story accessory dwelling unit/garage structure. We anticipate the artificial
fill material to have similar properties to those encountered during our investigation.
2.3 Laboratory Testing
The following includes a summary of the laboratory testing performed on collected subsurface samples.
Laboratory test results are presented in Appendix C.
A Grain-size distribution test was conducted on one bulk sample collected at a depth of 0 to 4 feet bgs. The
sample was classified as sand, with a fines content (passing Sieve No. 200) of 4 percent (USCS
classification of SP).
The same bulk sample was also tested for sulfate-content. Sulfate-content test results indicate that onsite
soils may be classified as "S0" (negligible) sulfate exposure per Table 19.3.1.1 of ACI-318. Based on testing
by others, we anticipate onsite soils to have "Very Low" expansion potential (Geo-Etka, 1994a).
2.4 Groundwater and Surface Water
Mapping by the California Division of Mines and Geology (CDMG, 1997) indicates historic high
groundwater to be less than 10 feet bgs. Groundwater was encountered during our investigation at depths
ranging from 3 to 3.5 feet bgs. Groundwater was also encountered during the prior exploration by others,
at a depth of approximately 4 feet bgs (Geo-Etka, 1994a). We have assigned a design groundwater depth
of 3 feet for our analysis. Groundwater levels are directly related to tidal fluctuations with lesser influence
by rainfall and is anticipated to fluctuate on a daily/hourly basis.
PA2022-0155
22077-01
July 12, 2022
9 220712_316 Grand Canal, Newport Beach (22077-01)
2.5 Regional Faulting and Seismicity
Regional Faults: The site is not located within a fault-rupture hazard zone as defined by the Alquist-Priolo
Special Studies Zones Act (CGS, 2018) and no evidence of active faulting was observed during this
exploration. Also, based on mapping by the State (Jennings and Bryant, 2010), there are no active faults
mapped at the site. Regional faults are presented on Figure 3.
Seismicity: Properties in southern California are subject to seismic hazards of varying degrees depending
upon the proximity, degree of activity, and capability of nearby faults. These hazards can be primary (i.e.,
directly related to the energy release of an earthquake such as surface rupture and ground shaking) or
secondary (i.e., related to the effect of earthquake energy on the physical world, which can cause
phenomena such as liquefaction and ground lurching). Since there are no active faults at the site, the
potential for primary ground rupture is considered low. The primary seismic hazard for this site is ground
shaking due to a future earthquake on a regional active fault.
Using the USGS deaggregation computer program (USGS, 2022) and the site coordinates of 33.6078 north
latitude and -117.8887 west longitude, the closest major active faults include the Newport-Inglewood Fault
and San Joaquin Hills Blind Thrust Fault. The maximum moment magnitude for the controlling fault is 7.1
MW, which would be generated from the San Joaquin Hills Fault; however, numerous other regionally active
faults could also produce ground shaking at the site during an earthquake.
The site is located in a potential liquefaction hazard zone as defined by the State's Seismic Hazard Mapping
Act. The site is not situated within a mapped earthquake-induced landslide zone. The attached Site
Location and Seismic Hazards Map (Figure 1) depicts the approximate location of the site relative to seismic
hazard zones, as shown on the State of California Seismic Hazard Zones Map for the Newport Beach
Quadrangle (CDMG, 1998). A discussion of the liquefaction hazard and analysis is presented in Section
2.7.
Tsunami hazard is considered high as the site is located within a mapped tsunami hazard zone (CGS, 2021),
is situated adjacent to the Pacific Ocean, and is at an elevation of approximately 6 to 9 feet above mean sea
level (msl).
2.6 Slope Stability
The subject site is situated on a flat lot and is not located within a mapped earthquake-induced landslide
zone. Additionally, no new permanent slopes are planned for the subject site. Temporary slope stability for
proposed excavations will be mitigated by appropriate lay back and/or shoring, if required.
2.7 Liquefaction Potential
Liquefaction is a phenomenon in which earthquake-induced stress generates excess pore water pressure in
low density, saturated, sandy and silty soils below the groundwater table. Liquefaction causes a loss of
strength and is often accompanied by ground settlement. For liquefaction to occur, the following four
conditions must be present at the site: 1) Severe ground shaking, such as during a strong earthquake, 2) Soil
must be saturated or nearly saturated, generally below the groundwater table, 3) Corrected normalized
standard penetration test (SPT) blow counts (N1) and/or CPT tip resistance (Qt) must be relatively low, and
4) Soils must be granular (typically sand or sandy silt) with low plasticity; clays and silts of relatively high
plasticity are generally not liquefiable.
PA2022-0155
22077-01
July 12, 2022
10 220712_316 Grand Canal, Newport Beach (22077-01)
As discussed in Section 2.5, the subject site is situated within a mapped potential liquefaction hazard zone;
thus, a liquefaction hazard assessment was performed as part of this study. Our assessment was performed
using CLiq software, version 3.4.1.4 by Geologismiki. Liquefaction potential was performed using the
Robertson method (NCEER R&W 2009a). CLiq provides CPT data interpretation, final plots of factor-of-
safety, liquefaction potential index, and post-earthquake displacement, including vertical settlement.
The liquefaction potential of onsite soils was estimated based on a peak ground acceleration of 0.66g and a
maximum earthquake magnitude of 7.1 MW, as determined in our site seismicity analysis and discussed in
Sections 2.5 and 3.3. An in-situ groundwater table of 3.5 feet bgs and a seismic (design) groundwater table
of 3 feet were used in our analysis. Per our review of the project plans, we included an average of two feet
of design fill over the existing grades for our analysis.
Seismic Settlement: The results of our analysis indicate that liquefiable layers are present and, when
subjected to ground accelerations generated during a large earthquake event near the subject site, may be
prone to settlement. Based on our calculations, settlement due to liquefaction is estimated to be
approximately 3-inches. The graphic representations of the CPT sounding are included in Appendix B and
the liquefaction analysis is presented in Appendix E.
Loss of Bearing and Surface Manifestations: The potential for loss of bearing was reviewed based on the
thickness of the liquefiable layers that will be left in-place, versus the amount of fill and non-liquefiable
native soils overlying liquefiable soils. Local surface disruptions and loss of bearing strength at the surface
may occur; however, considering that the proposed residential building will be supported on a mat slab that
is underlain by two layers of geogrid and compacted fill, the impact to the structure is anticipated to be low.
Surface manifestations are also considered a secondary seismic hazard at the site due to the interlayered
sandy soils extending to near-surface and very shallow groundwater condition. There is a potential for
ground failure (surface cracks, sand boils, etc.) to occur during a strong earthquake event resulting in
liquefaction. As discussed before, considering that the proposed residential building foundations will be
underlain by two layers of geogrid and 3 to 5 feet of compacted fill, the impact to the structure is anticipated
to be low.
Lateral Spread: The subject site is essentially flat, thus lateral spread potential is anticipated to be low.
Additionally, the recommended remedial grading (see Section 3.2) will include removal and recompaction
of the soils in the upper 3 feet and reinforcement with geogrid. There is also an existing seawall along Grand
Canal, approximately 8 feet to the west. While we anticipate some lateral movement may occur during a
strong (design) seismic event, we expect the lateral movement of the proposed residential unit to be
relatively minor (less than the maximum acceptable values specified in the building code for conventional
foundations), provided that the foundations are placed over the reinforced compacted fill.
2.8 Settlement and Foundation Considerations
In general, the anticipated settlements depend upon the building loads, type of foundations, and the
geotechnical properties of the supporting subgrade. Considering the subsurface soil conditions and
relatively lightly loaded residential structure, we estimate total settlement (combined static and seismic) to
be on the order of 4-inches and differential settlement to be on the order of 2-inches over a 40-foot span.
This assumes remedial grading measures recommended in Section 3.2 of this report are implement during
grading of the site. Structural mat slab with thickened edges should be anticipated for the proposed
residential structure upon evaluation by the project structural engineer.
PA2022-0155
22077-01
July 12, 2022
11 220712_316 Grand Canal, Newport Beach (22077-01)
3.0 CONCLUSION AND RECOMMENDATIONS
3.1 General Conclusion and Recommendation
Based on the results of our preliminary exploration, the proposed new residential construction and associated
improvements, as described herein, are considered geotechnically feasible provided the recommendations in
this report are implemented during design, grading and construction. Proposed grading is anticipated to be
relatively minor and generally consist of design fills on the order of 1 to 3 feet in order to reach pad grades
and provide for proper site drainage. The near-surface soils consist of artificial fill and weathered estuarine
deposits that are considered unsuitable to receive compacted fill or for structural support of foundation
elements. Thus, remedial removals during grading are recommended to provide a uniform compacted fill
blanket and reduce the potential liquefaction hazard. Removals should extend to a minimum depth of 3-
feet below existing grades. Locally deeper removals may be necessary, based on field conditions
encountered. Actual limits and depth of removal will be determined by SA GEO during grading. Upon
completion of remedial removals, one layer of geogrid (Miragrid 8XT or approved equivalent) is
recommended to be placed on the bottom, prior to placement of fill. A second layer should be placed one
foot above the initial layer, perpendicular to the initial layer.
Our recommendations are based on anticipated geotechnical conditions, which should be verified during
grading and construction. Additional soil testing and/or revised recommendations may be required if
exposed geotechnical conditions vary from the anticipated conditions presented in this report. Geotechnical
observation and testing should be conducted during grading and construction operations. The
recommendations in this report are considered minimum and may be superseded by more stringent
requirements of others.
Due to the absence of specific foundation, retaining wall and grading plans, the conclusions and
recommendations provided herein should be considered preliminary and subject to change. The future
precise grading, foundation, retaining wall and landscape plans should be reviewed by the geotechnical
consultant to confirm the actual design conditions outlined in this report.
3.2 Site Preparation and Earthwork
Site preparation and grading should be performed in accordance with the recommendations provided herein
and the requirements of the City of Newport Beach. SA GEO’s General Earthwork and Grading
Specifications are included in Appendix F.
3.2.1 Site Demolition and Clearing
Prior to remedial grading, deleterious materials and debris should be cleared from the site and disposed
of offsite. Excavations for the removal of existing foundation elements, utilities, and vegetation,
including onsite trees/shrubs, should be observed by the geotechnical consultant. Large roots, highly
organic soils, and existing utilities should be removed from the site and should not be incorporated
into new fills.
Soil that is disturbed as part of excavations or removal of trees, underground utilities, or existing
structures should be evaluated by the geotechnical consultant. Excavations that require backfill should
be properly documented and compacted upon the removal and replacement of the disturbed soil under
the observation and testing of the geotechnical consultant.
PA2022-0155
22077-01
July 12, 2022
12 220712_316 Grand Canal, Newport Beach (22077-01)
3.2.2 Protection of Existing Improvements and Utilities
Existing buildings, improvements, and utilities adjacent to the site that are to be protected in place
should be located and visually marked prior to grading operations. Excavations adjacent to
improvements to be protected in-place or any utility easement should be performed with care, so as
not to undermine existing foundations or destabilize the adjacent ground. The adjacent properties
should be surveyed and/or photo documented by the project contractor prior to demolition and
grading.
Stockpiling of soils more than 5 feet in height at or near existing structures and over utility lines
should not be allowed. If deeper removals are required, shoring or other measures (i.e., setback or
laybacks) to provide safety and mitigate the potential for lateral/vertical movements may be required.
3.2.3 Remedial Grading Measures
Design fills are anticipated to be on the order of 1 to 3 feet. The materials exposed at existing grade
are anticipated to consist of artificial fills and/or weathered estuarine soils, which are not considered
suitable for structural support of foundations or to receive compacted fill material. Removals should
extend to a minimum depth of 3-feet below existing grades. Locally, deeper removals may be
required if undocumented fill material and/or unsuitable native soils are encountered. Where not
limited by adjacent structures/properties, the removals should extend a minimum of 5 feet beyond
the limits of the proposed building footprints. Actual limits and depth of removal will be determined
by SA GEO during grading. The bottom of all remedial removals should be observed by the
geotechnical consultant and approved in writing prior to fill placement.
Two layers of geogrid reinforcement (Miragrid 8XT or approved equivalent) should be placed, with
the deeper layer placed on the removal bottom and the second layer placed one foot above the first
layer, separated by one foot of compacted fill. The geogrid layers should be placed perpendicular to
each other along the strong axis. All structural foundations should be underlain by a minimum of 3
feet of compacted fill and two layers of geogrid, as discussed herein. Where no significant structures
are anticipated, the geogrid layers may be omitted upon review and approval by the geotechnical
consultant. The geogrid layers should extend a minimum of 5 feet, laterally, beyond the foundations
for the residential structure, where not limited by property boundaries.
Where excavations expose wet, soft material at or below the groundwater table and is considered too
saturated for proper soil compaction, stabilization of the subgrade soils may be required. Stabilization
of the removal bottom may be achieved by placing 6 to 18 inches of 1- to ¾-inch crushed rock in
addition to the geogrid layers discussed above. The conditions should be reviewed in the field by the
project contractor and the geotechnical consultant prior to implementation of these mitigation
measures. Additional recommendations may be provided by the geotechnical consultant during the
grading and as needed.
Temporary slopes exposing onsite materials should be cut in accordance with Cal/OSHA
Regulations. It is anticipated that the exposed onsite earth materials will predominately consist of
loose to medium dense artificial fill and estuarine deposits. Temporary excavations along the project
boundaries may be made at a 1:1 inclination to a maximum height of 3-feet, pending review by the
geotechnical consultant. Dry or running sands may require flatter laybacks. Areas with spatial
limitations that don’t allow for laybacks or where surcharges occur should be shored for the duration
of the temporary excavation exposure. Temporary excavations made along the property boundaries
during remedial grading should be backfilled the same day and no excavations should be left
unsupported overnight. In general, temporary excavations should be field reviewed by the
geotechnical consultant on a regular basis. Temporary excavations should be covered with visqueen
and sandbag protected from runoff during rainy seasons and/or when rainfall is anticipated.
PA2022-0155
22077-01
July 12, 2022
13 220712_316 Grand Canal, Newport Beach (22077-01)
Flatter laybacks, shoring and/or slot cutting could be required if groundwater/seepage zones or
unstable layers are encountered within excavations. Excavations should proceed in a manner so as
not to remove lateral or bearing support of adjacent properties, structures, or other improvements.
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. Cuts should not be allowed to dry out and should not be left
open for extended time periods. The contractor should consider the use of excavation treatments that
help the soils retain moisture for any cuts left open more than several days.
3.2.4 Fill Placement
Upon the completion of remedial excavation measures, the approved removal bottoms should be
scarified a minimum of 6 inches. The removal bottoms and fill materials should be compacted to at
least 90 percent of maximum dry density, as determined by ASTM Test Method D1557. Fill
materials should be placed in loose lifts no thicker than 6 inches.
Fill materials should be relatively free of deleterious material. The existing artificial fill and native soils
at the site should generally be suitable for re-use as compacted fill. Any oversize greater than 6 inches
in any dimension should be broken into smaller fragments or disposed of offsite. We recommend that
the moisture content of new compacted fill soils be above the optimum moisture content but within
the compactable moisture range. Appropriate equipment support or other measures (e.g., mixing,
stockpiling, drying) may be needed to achieve the uniform and correct moisture content for placement
of the fill. If the soils become extremely wet, special measures for mixing and drying may be required
that should be determined by the geotechnical consultant based on the actual field conditions.
Any import soils to be used as fill material should have engineering properties equal to or better than
those onsite and should be evaluated and accepted by the geotechnical consultant prior to import. At
minimum, we recommend that the import soils have Expansion Index of less than 50, plasticity index
of less than 15 and fine content (passing Sieve No. 200) of less than 50 percent.
3.3 Seismic Design Parameters
The following table summarizes the seismic design criteria for the subject site. The seismic design
parameters are developed in accordance with ASCE 7-16 and 2019 CBC. Please note that, considering the
proposed structure and anticipated structural periods, site-specific ground-motion hazard analysis was not
performed for the site. The seismic response coefficient, Cs, should be determined per the parameters
provided below and using equation 12.8-2 of ASCE 7-16.
PA2022-0155
22077-01
July 12, 2022
14 220712_316 Grand Canal, Newport Beach (22077-01)
Selected Seismic Design Parameters
from 2019 CBC/ASCE 7-16
Seismic Design
Values Reference
Latitude 33.6078 North
Longitude -117.8887 West
Controlling Seismic Source Newport Inglewood USGS, 2022
Site Class per Table 20.3-1 of ASCE 7-16 D
Spectral Acceleration for Short Periods (Ss) 1.37 g SEA/OSHPD, 2022
Spectral Accelerations for 1-Second Periods (S1) 0.49 g SEA/OSHPD, 2022
Site Coefficient Fa, Table 11.4-1 of ASCE 7-16 1.0 SEA/OSHPD, 2022
Site Coefficient Fv, Table 11.4-2 of ASCE 7-16 1.81
Design Spectral Response Acceleration at Short Periods
(SDS) from Equation 11.4-4 of ASCE 7-16 0.91 g SEA/OSHPD, 2022
Design Spectral Response Acceleration at 1-Second
Period (SD1) from Equation 11.4-4 of ASCE 7-16 0.59 g
TS, SD1 /SDS 11.4.6 of ASCE 7-16 0.65 sec
TL, Long-Period Transition Period 8 Sec SEA/OSHPD, 2022
Peak Ground Acceleration Corrected for Site Class Effects
(PGAM) from Equation 11.8-1 of ASCE 7-16 0.66 g SEA/OSHPD, 2022
Seismic Design Category, Section 11.6 of ASCE 7-16 D
3.4 Foundation Design
Due to seismic induced liquefaction potential beneath the subject site, a stiffened foundation such as a mat
slab with deepened perimeter footings is recommended for support of the proposed residence.
Design of slabs and foundations are the purview of the structural engineer. For preliminary design, the
sizing of foundations may be based on an allowable bearing capacity of 1,200 psf for a 12-inch-wide
perimeter footing embedded a minimum of 18 inches below the nearest adjacent grade. The allowable
bearing capacity may be increased by 500 psf for each additional foot of embedment and by 200 psf for
each additional foot of width to a maximum value of 2,500 psf. The allowable bearing pressure may be
increased by one-third for wind or seismic loading. An allowable bearing capacity of 1,200 psf may be used
for design of the mat slab. Lateral loads may be resisted by passive pressure forces and friction acting on
the bottom of footings and mat slabs. For footings cast against approved earth materials, the lateral bearing
resistance may be computed using a value of 300 pounds per square foot per foot of depth below natural
level grade, but should not exceed 4,500 pounds per square foot. The coefficient of frictional resistance of
0.35 against sliding for concrete in contact with approved soil may also be used. Passive resistance and
frictional resistance may be used in combination without reduction. Mat slabs should be a minimum of 12
inches thick with reinforcement grids at the top and bottom. Mat slab should be provided with
deepened/thickened edges that are a minimum of 18 inches below adjacent grades. The thickened edge
should be tapered and have a minimum width of 12 inches. Mat slabs may be designed using a coefficient
of subgrade reaction of 100 pci. Foundations and slabs should be designed to tolerate the estimated total
and differential settlements includes in Section 3.7 of this report.
Exposed slabs should be designed with appropriately spaced expansion joints, as needed, to limit the
visibility of unsightly, irregular cracks. Contractors should be advised to take appropriate precautions such
as maintaining proper concrete slump and providing proper concrete curing, particularly when pouring
concrete during hot, dry or windy weather, in order to limit potential cracking of large slabs.
PA2022-0155
22077-01
July 12, 2022
15 220712_316 Grand Canal, Newport Beach (22077-01)
3.5 Slope Setbacks
Footings for the proposed improvements should be excavated such that the bottom outside face of all
structural foundation elements are a horizontal distance of H/3 (H = slope height) from the slope face or
structural setback plane, up to a maximum horizontal setback of 40-feet per section 1808.7.1 of the 2019
California Building Code. Structural setbacks shall be verified by the geotechnical consultant when the
final plans become available.
3.6 Interior Slab Moisture Mitigation
In addition to geotechnical and structural considerations, the project owner should also consider moisture
mitigation when designing and constructing mat slabs or slabs-on-grade. The intended use of the interior
space, type of flooring, and the type of goods and/or materials in contact with the floor may dictate the need
for, and design of, measures to mitigate potential effects of moisture emission from and/or moisture vapor
transmission through the slab. A vapor retarder or barrier is required in accordance with Section 1805.2.1
of the 2019 CBC under residential and garage slabs to help mitigate moisture transmission through the
concrete. Slabs should additionally be underlain by 4-inches of open graded gravel and slab subgrade soils
should be well-moistened prior to placement of the vapor retarder. All subgrade materials should be
geotechnically approved prior to placing the gravel for the slab underlayment.
Slab underlayment is deferred to the project architect; however, in accordance with the American Concrete
Institute, we suggest that slabs be underlain by a 15-mil thick vapor retarder/barrier (Stego Wrap or
equivalent) placed over the gravel in accordance with the requirements of ASTM E:1745 and E:1643.
Concrete mix design and curing are also significant factors in mitigating slab moisture problems. Concrete
with lower water/cement ratios results in denser, less permeable slabs. They also "dry" faster with regard
to when flooring can be installed (reduced moisture emissions quantities and rates). Rewetting of the slab
following curing should be avoided since this can result in additional drying time required prior to flooring
installation. Proper concrete slab moisture testing prior to flooring installation is also important.
Also, the concrete mix design and the type and location of the vapor retarder should be determined in
coordination with all parties involved in the finished product, including the project owner, architect,
structural engineer, geotechnical consultant, concrete subcontractors, and flooring subcontractors.
3.7 Settlement Potential
Based on the subsurface conditions, recommended remedial measures and the anticipated foundation loads
associated with the proposed residential structure, the total settlement is estimated to be on the order of 4-
inches and the post-construction differential settlement is anticipated to be approximately 2-inches over a
40-foot span. These values include combined static and seismic induced settlement and should be used by
the structural engineer to properly design the foundations and structural (mat) slab for the proposed
improvements including the residential building.
PA2022-0155
22077-01
July 12, 2022
16 220712_316 Grand Canal, Newport Beach (22077-01)
3.8 Retaining Walls
The recommended lateral earth pressures for competent onsite soils (bedrock and compacted fill) in drained
conditions are as follows:
Equivalent Fluid Unit Weight Pressure (psf/ft.)
Static Conditions Horizontal Adjacent Ground 2:1 Slope
Active 40 60
At Rest 60 90
Passive 300 160
In addition to the above lateral forces due to retained earth, the influence of surcharge due to other loads
such as adjacent footings, vehicular traffic or lateral loads acting on the retaining wall should be considered
during the design of retaining walls. Recommendations for drainage behind retaining walls are provided
in the attached detail (Figure 4, rear of text).
To design an unrestrained retaining structure, such as a cantilever wall, the active earth pressure may be
used. For a restrained retaining structure, such as a basement wall or at restrained-wall corners, the at-rest
pressure should be used. Retaining Wall foundations should utilize the parameters included in Section 3.4
of this report.
For sliding resistance, the friction coefficient of 0.35 may be used at the concrete and soil interface.
The coefficient of friction may be combined with passive pressure and increased by one-third for
wind and seismic loading. The retaining walls, if any, will need to be designed for additional lateral
loads if other structures or walls are planned within a 1H:1V projection
We do not anticipate the proposed walls at the site will retain more than 6 feet of soil. Thus, per the 2019
California Building Code, seismic lateral earth pressure will not need to be applied (2019 CBC Section
1803.5.12).
Drainage behind retaining walls should also be provided. A recommended drainage design for achieving
control of seepage forces behind retaining walls consists of open graded gravel wrapped with geotextile
fabric separator or a graded washed gravel placed in contact with undisturbed native material. Collection
is with a 4-inch diameter perforated pipe embedded at the base of the gravel tied to a 4-inch diameter non-
perforated outlet pipe which discharges at convenient locations selected during foundation plan review.
The pipe should be placed such that the gradient is not less than 0.01 ft./ft. The fabric wrapped gravel
envelope should be placed at a similar gradient.
All drainpipe should be Schedule 40, SDR-35, or approved equivalent. Perforations may be either bored
holes, not less than 3/16-inch or larger than 1/2-inch diameter, or 1/8-inch slots placed on the bottom one-
third of the pipe perimeter. If the pipe is to be bored, a minimum of 5 holes should be uniformly placed per
foot of length in two rows at approximately the 4 and 8 o’clock positions. Slots should not exceed 2 inches
in length and total length of slots should not be less than 50 percent of the pipe length. Subdrain pipes are
intended for evacuation of water, and as such the holes on the pipes should be directed downward on the
lower portion of the pipe.
PA2022-0155
22077-01
July 12, 2022
17 220712_316 Grand Canal, Newport Beach (22077-01)
The geotextile filter fabric should be in accordance with Orange County Standard Plan 1808. The fabric
pore spaces should be between 30 and 100 mesh openings. The fabric should be placed such that a
minimum lap of 6 inches exists at all splices. The fabric wrapped gravel envelope should consist of 1/2-inch
minimum single size drain rock. All subdrain installations should be inspected by this office or designated
representative.
3.9 Corrosivity
Based on laboratory testing, soluble sulfates exposure in the onsite soils may be classified as "S0" per Table
19.3.1.1 of ACI-318-14. Structural concrete elements in contact with soil include footings and building
slabs-on-grade. The flatwork and sidewalk concrete are typically not considered structural elements.
Concrete mix for structural elements should be based on the "S0" soluble sulfate exposure class of Table
19.3.2.1 in ACI-318-14. Other ACI guidelines for structural concrete are recommended. Also, onsite soils
are anticipated to be corrosive to metals. Laboratory test results are included in Appendix C of this report.
3.10 Exterior Concrete
The driveway, patio slabs and other flatwork elements should be at least 4 inches thick (actual) and
minimum steel reinforcement should consist of No. 3 bars placed on chairs 24 inches on center both ways.
Concrete slabs should be provided with construction or weakened plane control joints at a maximum
spacing of 10 feet. The control joints should have a thickness that is ¼ of the total concrete thickness. We
recommend that the upper 6 inches of subgrade be pre-saturated to 110 percent of optimum moisture
content.
Exterior concrete elements such as curb and gutter, driveways, sidewalks, and patios are susceptible to
lifting and cracking when constructed over expansive soils. With expansive soils, the impacts to
flatwork/hardscape can be significant, generally requiring removal and replacement of the affected
improvements. Please also note that reducing concrete problems is often a function of proper slab design,
concrete mix design, placement, and curing/finishing practices. Adherence to guidelines of the American
Concrete Institute (ACI) is recommended. Also, the amount of post-construction watering, or lack thereof,
can have a very significant impact on the adjacent concrete flatwork.
For exterior slabs, the use of a granular sublayer is primarily intended to provide a better working surface
over the subgrade material. It also helps retain the added moisture in the native soil in the event that the
slab is not placed immediately. Where these factors are not significant, the layer may be omitted. If used,
we recommend placement of 2 to 4 inches of granular material over subgrade soils.
On projects with expansive soils, additional measures such as thickened concrete edges/footings, subdrains
and/or moisture barriers should be considered where planter or natural areas with irrigation are located
adjacent to the concrete improvements. Design and maintenance of proper surface drainage is also very
important. If the concrete will be subject to heavy loading from cars/trucks or other heavy objects, at
minimum, a 6-inch-thick concrete pavement section should be used.
The above recommendations typically are not applied to curb and gutter but should be considered in areas
with highly expansive soils.
PA2022-0155
22077-01
July 12, 2022
18 220712_316 Grand Canal, Newport Beach (22077-01)
3.11 Trench Excavation and Backfill
Excavations should be performed in accordance with the requirements set forth by Cal/OSHA Excavation
Safety Regulations (Construction Safety Orders, Section 1504, 1539 through 1547, Title 8, California Code
of Regulations). In general, onsite soils are anticipated to be classified as Type "C". Cal/OSHA regulations
apply to excavations that are up to 20 feet deep.
Trenches, including interior utility, should be backfilled with native soil and compacted to 90 percent relative
compaction. We recommend that backfill soils be placed above the optimum moisture content.
Where excavations expose wet, soft material below the groundwater table that is considered too saturated,
stabilization of the subgrade soils may be required. The excavation bottom may be stabilized by placing a
layer of approved geofabric with 6 to 18 inches of 1- to ¾-inch crushed rock. Alternatively, crushed
aggregate base material may be suitable for stabilization. These options should be reviewed and accepted
by the project team based on actual field conditions.
Where utility lines transect footings, any bedding sand or gravel backfill should be "dammed" with
compacted on-site soils or slurry to limit the potential for water to enter beneath slab areas through bedding
sand or gravel. Contractors are advised to notify this office of backfilling operations and keep a record or
map of the location of utility line trenches. Certain review agencies (City and County) require reporting of
all utility and sewer trench backfills to include location, depth and backfill compaction test results. It is the
builder’s responsibility to ensure that trench backfills are documented and tested as required by the building
or grading inspector for the project location.
3.12 Groundwater
As previously discussed, groundwater was encountered during our exploration and the prior exploration by
others at depths ranging from 3 to 4 feet. Groundwater, seepage, and/or saturated soils should be anticipated
during remedial grading and may cause caving in steep sided excavations.
Dewatering is not anticipated to be required provided that remedial grading excavations are promptly
scarified, geo-grid reinforced, and backfilled with compacted fill. Groundwater levels are directly related
to tidal fluctuations with lesser influence by rainfall. The contractor should review tide tables and the
construction/grading schedule to ensure efficient grading operations, however, stabilization of the removal
bottom may be required (see section 3.2.2).
Subdrains and waterproofing should be included in retaining wall design and construction as a precaution
against the development of hydrostatic pressure loading walls and/or seepage/nuisance water issues.
Additional drainage recommendations may be provided during and following grading.
3.13 Stormwater Infiltration
On-site stormwater infiltration is not recommended considering that the site will be underlain by compacted
artificial fill over estuarine deposits with a shallow historic/design groundwater condition (3 feet bgs). Other
methods of stormwater management should be evaluated by the project civil engineer, as needed.
PA2022-0155
22077-01
July 12, 2022
19 220712_316 Grand Canal, Newport Beach (22077-01)
3.14 Surface Drainage and Irrigation
Finished grades should be designed and constructed so that no water ponds in the vicinity of foundations.
Drainage design in accordance with the 2019 California Building Code, Section 1804.4 is recommended or
per local city/county requirements. Roof gutters should be installed with outflow directed away from the
house in a non-erosive manner as specified by the project civil engineer or landscape architect. Proper
interception and disposal of onsite surface discharge is presumed to be a matter of civil engineering or
landscape architectural design.
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.
The Owner should be aware of 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. Sources of uncontrolled water, such as leaky water
pipes or drains, should be repaired if identified.
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 at least 5 feet from building foundations. Planters and lawn areas
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 and drained with a subdrain. Also, to reduce the
potential for soil drying and shrinkage, root barriers should be considered along foundations next to heavily
landscaped areas.
Landscape irrigation water should be controlled 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 foundations and must therefore be avoided. Any planters located adjacent to the
building foundation must be lined in a manner that directs subsurface water at least 5 feet from the building
before infiltration into the soil below.
On-site surface soils are anticipated to have relatively low permeability after grading. It is strongly
recommended that surface water be collected and directed to a suitable off-site outlet rather than allowed
to infiltrate into the soil.
3.15 Review of Future Plans
Future grading and improvement plans should be reviewed and accepted by the geotechnical consultant.
Additional recommendations or modifications to the recommendations provided herein may be necessary
depending on the extent of the changes. SA GEO should also review the foundation, retaining wall, and
landscape plans for conformance with the geotechnical design parameters. SA GEO shall not be
responsible for any deviation, change or revision to plans, which are not approved by SA GEO.
PA2022-0155
22077-01
July 12, 2022
20 220712_316 Grand Canal, Newport Beach (22077-01)
3.16 Observation and Testing during Grading and Construction
Geotechnical observation and testing should be performed by SA Geo during the following phases of
grading and construction:
During site demolition, preparation and clearing;
During remedial grading and excavations to relocate or remove existing underground improvements;
During earthwork, including observation and acceptance of remedial removal bottoms and fill
placement, including import material;
During placement of geogrid layers;
Following the completion of grading, in order to verify soil properties for foundations, slab-on-grade
and pavements;
Upon completion of any foundation or structural excavation, prior to pouring concrete;
During slab and flatwork subgrade preparation prior to pouring of concrete;
During placement of backfill for utility trenches;
During placement of backfill for retaining structures;
During installation and backfill of subdrainage systems; and
When any unusual soil conditions are encountered.
3.17 Limitations
This report has been prepared for the exclusive use of our client, Beachlife Rentals LLC within the scope
of services requested by our client for the subject property at 316 Grand Canal, City of Newport Beach, as
described herein. This report or its contents should not be used or relied upon for other projects or purposes,
or by other parties without the acknowledgement of SA GEO and the consultation of a geotechnical
professional. The means and methods used by SA GEO for this study are based on local geotechnical
standards of practice, care, and requirements of governing agencies. No warranty or guarantee, expressed
or implied, is given.
Our findings, conclusions, and recommendations are professional opinions based on interpretations and
inferences made from geologic and engineering data from specific locations and depths, observed or
collected at a given time. By nature, geologic conditions can vary from point to point, can be very different
in-between exploration points, and can also change over time. Our conclusions and recommendations are,
by nature, preliminary and subject to verification and/or modification during grading and construction when
more subsurface data is exposed.
PA2022-0155
Source: Seismic Hazard Zones, Newport Beach Quadrangle, 1998
Site Location and Seismic Hazard Map
Site Location
Beachlife Rentals LLC
316 Grand Canal
Newport Beach, California
Project Number: 22077‐01
Date: July 2022
Figure 1
PA2022-0155
Source: Geologic Map of the Santa Ana and San Bernardino 30’ x 60’ Quadrangle, USGS 2006
Regional Geologic Map
Site Location
Beachlife Rentals LLC
316 Grand Canal
Newport Beach, California
Project Number: 22077‐01
Date: July 2022
Figure 2
PA2022-0155
Source: Fault Activity Map of California, CGS 2010
Regional Fault Map
Site Location
Beachlife Rentals LLC
316 Grand Canal
Newport Beach, California
Project Number: 22077‐01
Date: July 2022
Figure 3
PA2022-0155
Retaining Wall Drainage Detail
Figure 4
PA2022-0155
Appendix
A
PA2022-0155
A-1
APPENDIX A
REFERENCES
ASCE/SEI 7-16, Minimum Design Loads and Associated Criteria for Buildings and Other
Structures.
California Building Standards Commission, 2019 California Building Code, Title 24, Part 2.
California Building Standards Commission, California Green Building Standards Code, California
Code of Regulations, Title 24, Part 11, effective date January 1, 2011.
California Division of Mines and Geology (CDMG), 1997, Seismic Hazard Zone Report for the
Anaheim and Newport Beach 7.5-Minute Quadrangles, Orange County, California,
Seismic Hazard Zone Report 03.
California Division of Mines and Geology (CDMG), 1998, Seismic Hazards Zone Map, Newport
Beach Quadrangle, Official Map dated April 15, 1998.
California Geological Survey (CGS), 2008, Guidelines for Evaluation and Mitigating Seismic
Hazards in California, Special Publication 117A.
California Geological Survey (CGS), 2018, Earthquake Fault Zones, A Guide for Government
Agencies, Property Owners / Developers, and Geoscience Practitioners for Assessing
Fault Rupture Hazards in California, Special Publication 42, Revised 2018.
California Geological Survey (CGS), 2021, Tsunami Hazard Area Map, County of Orange,
California, Official Map dated July 8, 2021.
Coast Geotechnical, Inc., 2014, Geotechnical Engineering Investigation of Proposed New
Residence at 308 Grand Canal, Newport Beach, California, W.O. 469413-01, Dated
February 17, 2014.
Geo-Etka, Inc., 1994a, Preliminary Foundation Soils Exploration at 316 Grand Canal, Balboa,
California, Job No.: F-6876-94, Dated May 31, 1994.
Geo-Etka, Inc., 1994b, Compaction Report for the Building Pad, 316 Grand Canal, Balboa,
California, Job No.: C-6876-94, Dated June 10, 1994.
Google Earth Pro, 2022. V7.3.25491, https://www.google.com/earth/desktop/
Ishihara, K., 1985, Stability of Natural Deposits During Earthquakes, Proceedings of the Eleventh
International Conference on Soil Mechanics and Foundation Design, San Francisco,
California, Volume 1, August 1985.
Jennings, Charles W. and Bryant W.A., 2010, Fault Activity Map of California, Department of
Conservation, California Geological Survey, Geologic Data Map No. 6.
PA2022-0155
A-2
Nationwide Environmental Title Research, LLC (NETR), 2022, Historic Aerials by NETR
Online, Date Accessed: June 28, 2022; website address: http://historicaerials.com
Robertson, P.K., 1990, Soil Classification using the Cone Penetration Test. Canadian Geotechnical
Journal, Vol. 27, pp 151-158.
Robertson, P.K. and Wride, C.E., 1998, Evaluating Cyclic Liquefaction Potential Using the Cone
Penetration Test, Canadian Geotechnical Journal, Ottawa, Volume 35, No. 3, 1998.
Robertson, P.K., 2009a, Interpretation of Cone Penetration Tests – a unified approach, Canadian
Geotechnical Journal, Vol. 46, No. 11, pp 1337-1355.
Robertson, P.K., 2009b, "Performance based earthquake design using the CPT," Keynote Lecture,
International Conference on Performance-based Design in Earthquake Geotechnical
Engineering – from case history to practice, IS-Tokyo, June 2009.
Structural Engineers Association/Office of Statewide Health Planning and Development, 2022,
U.S. Seismic Design Maps, web site address: https://seismicmaps.org/; Date Accessed:
June 24, 2022.
U.S. Geological Survey (USGS), 2006, Geologic Map of the Santa Ana and San Bernardino 30'
x 60' Quadrangles, California, Open File Report 2006-1217.
U.S. Geological Survey, 2022, Unified Hazard Tool, NSHM 2014 Dynamic Deaggregation
Program; web site address: https://earthquake.usgs.gov/hazards/interactive/; Date
Accessed: June 24, 2022.
Youd, T.L., Idrisss, I.M., et. al., 2001, Liquefaction Resistance of Soils: Summary Report from
the 1996 NCEER and 1998 NCEER/NSF Workshops on Evaluation of Liquefaction
Resistance of Soils, Journal of Geotechnical and Geoenvironmental Engineering,
American Society of Civil Engineers, Volume 127, No. 10, October 2001.
Zhang, G., Robertson P.K., Brachman, R. 2002, Estimating Liquefaction Induced Ground
Settlments from the CPT, Canadian Geotechnical Journal, 39: pp 1168-1180.
PA2022-0155
Appendix
B
PA2022-0155
Project: 316 Grand CanalSA Geotechnical, Inc.1000 N Coast Highway, #10Laguna Beach, CA 92651https://www.sageotechnical.com/Total depth: 20.74 ft, Date: 6/23/2022Newport Beach, CACone Operator: Kehoe Testing CPT-1Location:SBT IndexHAND AUGERIc SBT4321Depth (ft)20191817161514131211109876543210SBT IndexCone resistance qtHAND AUGERTip resistance (tsf)3002001000Depth (ft)20191817161514131211109876543210Cone resistance qtPore pressure uHAND AUGERPressure (psi)50Depth (ft)20191817161514131211109876543210Pore pressure uSBT legend1. Sensitive fine grained2. Organic material3. Clay to silty clay4. Clayey silt to silty clay5. Silty sand to sandy silt6. Clean sand to silty sand7. Gravely sand to sand8. Very stiff sand to clayey sand9. Very stiff fine grainedFriction ratioHAND AUGERRf (%)1086420Depth (ft)20191817161514131211109876543210Friction ratioSoil Behaviour TypeHAND AUGERSBT (Robertson, 2010)181614121086420Depth (ft)20191817161514131211109876543210Soil Behaviour TypeSilty sand & sandy siltSand & silty sandSilty sand & sandy siltClay & silty claySilty sand & sandy siltClay & silty claySilty sand & sandy siltSand & silty sandSandCPeT-IT v.3.7.1.12 - CPTU data presentation & interpretation software - Report created on: 6/30/2022, 5:51:44 AM1Project file: P:\2022\22077-01 316 Grand Canal, Newport Beach\CPeT-IT\22077-01.cptPA2022-0155
Log Of Boring
Date(s) Drilled: 6‐23‐2022 Logged By:AZ
Drilling Method: Hand Auger
Drill Rig Type: Manual
Sampling Method(s):
Drill Bit Size/Type:3” Hand Auger
Hammer Type:
Comments:NW Corner in Planter Area
Approximate Groundwater Depth (ft.):3.5
Total Depth
Drilled (ft)
Approximate Ground
Surface Elevation (ft)
HA‐1
TypeNumberUSCSDepth(ft)SAMPLES
MATERIAL DESCRIPTION
Moisture Content (%)Dry Density (pcf)REMARKS
0 Blows Per Foot5
10
15
20
Page 1 of 1
@ 0‐3’: Yellowish brown fine to medium SAND, damp,
loose, friable, micaceous. Moist by 2 feet.
4.5
6
SP
Notes:
Total Depth: 4.5‐Feet (Caving).
Groundwater Encountered at 3.5 Feet.
Backfilled With Cuttings.
@ 3‐4.5’: Interlayered gray silty SAND and minor sandy CLAY,
saturated, micaceous, medium dense/stiff.
Beachlife Rentals LLC
316 Grand Canal
Newport Beach, California
Project Number: 22077‐01
Date: July 2022
Appendix B
SM/
CL
Estuarine Deposits (Qes)
Loose/disturbed in upper 18 inches.
PA2022-0155
Log Of Boring
Date(s) Drilled: 6‐23‐2022 Logged By:AZ
Drilling Method: Hand Auger
Drill Rig Type: Manual
Sampling Method(s):
Drill Bit Size/Type:3” Hand Auger
Hammer Type:
Comments:SW Corner in Planter Area
Approximate Groundwater Depth (ft.):3.25
Total Depth
Drilled (ft)
Approximate Ground
Surface Elevation (ft)
HA‐2
TypeNumberUSCSDepth(ft)SAMPLES
MATERIAL DESCRIPTION
Moisture Content (%)Dry Density (pcf)REMARKS
0 Blows Per Foot5
10
15
20
Page 1 of 1
@ 0‐2.5’: Pale yellowish brown fine to medium SAND,
damp, loose, friable, some shells. Moist by 1.5 feet.
4.75
6
SP
Notes:
Total Depth: 4.75‐Feet (Caving).
Groundwater Encountered at 3.25 Feet.
Backfilled With Cuttings.
@ 2.5‐4.75’: Interlayered yellowish brown to gray silty
SAND/sandy CLAY, Reddish brown silty to clayey SAND, wet
to saturated, medium dense/stiff, micaceous.
Beachlife Rentals LLC
316 Grand Canal
Newport Beach, California
Project Number: 22077‐01
Date: July 2022
Appendix B
SM/
CL
Estuarine Deposits (Qes)
Loose/disturbed in upper 18 inches.
PA2022-0155
Log Of Boring
Date(s) Drilled: 6‐23‐2022 Logged By:AZ
Drilling Method: Hand Auger
Drill Rig Type: Manual
Sampling Method(s):
Drill Bit Size/Type:3” Hand Auger
Hammer Type:
Comments:Walkway along Southerly Property Line
Approximate Groundwater Depth (ft.):3.5
Total Depth
Drilled (ft)
Approximate Ground
Surface Elevation (ft)
HA‐3
TypeNumberUSCSDepth(ft)SAMPLES
MATERIAL DESCRIPTION
Moisture Content (%)Dry Density (pcf)REMARKS
0 Blows Per Foot5
10
15
20
Page 1 of 1
@ 0‐3’: Pale yellow brown fine to medium SAND, damp,
loose, friable, some shells. Moist by 1 foot.
4
7
SP
Notes:
Total Depth: 4.0‐Feet (Caving).
CPT‐1 Pushed through Hand‐Auger Hole.
Groundwater Encountered at 3.5 Feet.
Backfilled With Cuttings.
@ 4’: Brown to gray interlayered clayey SAND/sandy CLAY,
wet to saturated.
Beachlife Rentals LLC
316 Grand Canal
Newport Beach, California
Project Number: 22077‐01
Date: July 2022
Appendix B
SC/
CL
Estuarine Deposits (Qes)
Loose/disturbed in upper 18 inches. B‐1 @ 0‐4’
GS, EI, CCB‐1
PA2022-0155
Appendix
C
PA2022-0155
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.11101001,000
36
SIEVE OPENING IN INCHES
100 200
PERCENT PASSINGU.S. STANDARD
PARTICLE SIZE DISTRIBUTION
SP
Passing
2µ (%)
Passing
Sieve (%)
4
CActivity
PI/-2µMoistureSampleDepth
(feet)
BOULDERS COBBLES
GRAVEL
coarse
LL
Field
6
SILT OR CLAY
1-1/2 3/4 3/8
fine
PARTICLE SIZE (mm)
Symbol USCSNo. 200cCuPI
(%)
SAND
fine
U.S. STANDARD SIEVE NUMBERS HYDROMETER
12 8
coarse medium
3 50416 30
1.0
Boring
Number
HA-3
Number
B-1 0.0 - 4.0 3.5
SA GEO/316 Grand Canal (22077-01)
California
PROJECT NO. 22026-22
Template: NMSIV; Prj ID: 22026-22.GPJ; Printed: 6/30/22
Geotechnical, Inc.
PA2022-0155
Sample Compacted
Moisture
(%)
Compacted
Dry Density
(pcf)
Final
Moisture
(%)
Volumetric
Swell
(%)
Expansion
Index1
Value/Method
Expansive
Classification2 Soluble
Sulfate
(%)
Sulfate
Exposure3
HA-3
B-1
0-4'
-- -- -- -- -- -- -- 0.05 S0
Test Method:
ASTM D4829
HACH SF-1 (Turbidimetric)
Notes:
1. Expansion Index (EI) method of determination:
[A] E.I. determined by adjusting water content to achieve a 50 ±2% degree of saturation
[B] E.I. calculated based on measured saturation within the range of 40% and 60%
2. ASTM D4829 (Classification of Expansive Soil)
3. ACI-318-19 Table 19.3.1.1 (Exposure Categories and Classes)
Expansion Index
and Soluble
Sulfate
Test Results
(FRM001 Rev.5)
Project No. 22026-22
Project Name: SA Geo/316 Grand Canal (22077-01)
NMG
PA2022-0155
Appendix
D
PA2022-0155
PA2022-0155
PA2022-0155
PA2022-0155
PA2022-0155
PA2022-0155
PA2022-0155
Appendix
E
PA2022-0155
LIQ UEFACTION ANALYSIS REPORT
Input parameters and analysis data
Analysis method:Fines correction method:Points to test:Earthquake magnitude Mw:Peak ground acceleration:
NCEER (1998)NCEER (1998)Based on Ic value7.100.66
G.W.T. (in-situ):G.W.T. (earthq.):Average results interval:Ic cut-off value:Unit weight calculation:
Project title : 316 Grand Canal Location : Newport Beach, CA
SA Geotechnical, Inc.
1000 N Coast Highway, #10
Laguna Beach, CA 92651
https://www.sageotechnical.com/
CPT file : CPT-1
5.50 ft5.00 ft32.60Based on SBT
Use fill:Fill height:Fill weight:Trans. detect. applied:Kσ applied:
Yes2.00 ft120.00 lb/ft3
YesNo
Clay like behaviorapplied:Limit depth applied:Limit depth:MSF method:
Sands onlyNoN/AMethod based
Cone resistance
qt (tsf)2000Depth (ft)20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
Cone resistance SBTn Plot
HAND AUGER
Ic (Robertson 1990)4321
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0 SBTn Plot CRR plot
FILL
HAND AUGER
CRR & CSR 0.60.40.20
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
CRR plot
During earthq.
Qtn,cs 200180160140120100806040200Cyclic Stress Ratio* (CSR*)0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Liquefaction
No Liquefaction
Normalized friction ratio (%)0.1 1 10Normalized CPT penetration resistance1
10
100
1,000
Friction RatioHAND AUGER
Rf (%)1086420
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
Friction Ratio
Mw=71/2, sigma'=1 atm base curve Summary of liquefaction potential
FS Plot
HAND AUGER
FILL
Factor of safety 21.510.50
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
FS Plot
During earthq.
Zone A1: Cyclic liquefaction likely depending on size and duration of cyclic loading
Zone A2: Cyclic liquefaction and strength loss likely depending on loading and ground
geometry
Zone B: Liquefaction and post-earthquake strength loss unlikely, check cyclic softening
Zone C: Cyclic liquefaction and strength loss possible depending on soil plasticity,
brittleness/sensitivity, strain to peak undrained strength and ground geometry
CLiq v.3.4.1.4 - CPT Liquefaction Assessment Software - Report created on: 7/1/2022, 11:55:38 AM
Project file: P:\2022\22077-01 316 Grand Canal, Newport Beach\CLiq\22077-01.clq
1
PA2022-0155
This software is licensed to: SA Geotechnical, Inc.CPT name: CPT-1Cone resistanceqt (tsf)3002001000Depth (ft)20.52019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.54Cone resistanceCPT basic interpretation plotsFriction RatioHAND AUGERRf (%)1086420Depth (ft)20.52019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.54Friction RatioPore pressureHAND AUGERu (psi)86420Depth (ft)20.52019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.54Pore pressureInsituSBT PlotHAND AUGERIc(SBT)4321Depth (ft)1817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.543.532.521.510.50SBT PlotSoil Behaviour TypeHAND AUGERSBT (Robertson et al. 1986)1817161514131211109876543210Depth (ft)20.52019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.543.532.521.510.50Soil Behaviour TypeSilty sand & sandy siltSand & silty sandSilty sand & sandy siltClay & silty claySilty sand & sandy siltClay & silty claySilty sand & sandy siltSand & silty sandSandCLiq v.3.4.1.4 - CPT Liquefaction Assessment Software - Report created on: 7/1/2022, 11:55:38 AM2Project file: P:\2022\22077-01 316 Grand Canal, Newport Beach\CLiq\22077-01.clqInput parameters and analysis dataAnalysis method:Fines correction method:Points to test:Earthquake magnitude Mw:Peak ground acceleration:Depth to water table (insitu):NCEER (1998)NCEER (1998)Based on Ic value7.100.665.50 ftDepth to water table (erthq.):Average results interval:Ic cut-off value:Unit weight calculation:Use fill:Fill height:5.00 ft32.60Based on SBTYes2.00 ftFill weight:Transition detect. applied:Kσ applied:Clay like behavior applied:Limit depth applied:Limit depth:120.00 lb/ft3YesNoSands onlyNoN/ASBT legend1. Sensitive fine grained2. Organic material3. Clay to silty clay4. Clayey silt to siltyl5. Silty sand to sandy silt6. Clean sand to silty sand7. Gravely sand to sand8. Very stiff sand told9. Very stiff fine grainedPA2022-0155
This software is licensed to: SA Geotechnical, Inc.CPT name: CPT-1Norm. cone resistanceQtn200150100500Depth (ft)20.52019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.54Norm. cone resistanceCPT basic interpretation plots (normalized)Norm. friction ratioFr (%)1086420Depth (ft)20.52019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.54Norm. friction ratioNom. pore pressure ratioBq10.80.60.40.20-0.2Depth (ft)20.52019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.54Nom. pore pressure ratioSBTn PlotHAND AUGERIc (Robertson 1990)4321Depth (ft)2019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.543.532.521.510.50SBTn PlotNorm. Soil Behaviour TypeHAND AUGERSBTn (Robertson 1990)1817161514131211109876543210Depth (ft)20.52019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.543.532.521.510.50Norm. Soil Behaviour TypeSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSilty sand & sandy siltClay & silty clayClay & silty claySilty sand & sandy siltSilty sand & sandy siltSand & silty sandSand & silty sandSandCLiq v.3.4.1.4 - CPT Liquefaction Assessment Software - Report created on: 7/1/2022, 11:55:38 AM3Project file: P:\2022\22077-01 316 Grand Canal, Newport Beach\CLiq\22077-01.clqSBTn legend1. Sensitive fine grained2. Organic material3. Clay to silty clay4. Clayey silt to siltyl5. Silty sand to sandy silt6. Clean sand to silty sand7. Gravely sand to sand8. Very stiff sand told9. Very stiff fine grainedInput parameters and analysis dataAnalysis method:Fines correction method:Points to test:Earthquake magnitude Mw:Peak ground acceleration:Depth to water table (insitu):NCEER (1998)NCEER (1998)Based on Ic value7.100.665.50 ftDepth to water table (erthq.):Average results interval:Ic cut-off value:Unit weight calculation:Use fill:Fill height:5.00 ft32.60Based on SBTYes2.00 ftFill weight:Transition detect. applied:Kσ applied:Clay like behavior applied:Limit depth applied:Limit depth:120.00 lb/ft3YesNoSands onlyNoN/APA2022-0155
This software is licensed to: SA Geotechnical, Inc.CPT name: CPT-1Total cone resistanceqt (tsf)3002001000Depth (ft)20.52019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.5Total cone resistanceLiquefaction analysis overall plots (intermediate results)SBTn IndexHAND AUGERIc (Robertson 1990)4321Depth (ft)20.52019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.54SBTn IndexNorm. cone resistanceQtn200150100500Depth (ft)20.52019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.54Norm. cone resistanceGrain char. factorKc109876543210Depth (ft)20.52019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.54Grain char. factorCorrected norm. cone resistanceQtn,cs200150100500Depth (ft)20.52019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.54Corrected norm. cone resistancCLiq v.3.4.1.4 - CPT Liquefaction Assessment Software - Report created on: 7/1/2022, 11:55:38 AM4Project file: P:\2022\22077-01 316 Grand Canal, Newport Beach\CLiq\22077-01.clqInput parameters and analysis dataAnalysis method:Fines correction method:Points to test:Earthquake magnitude Mw:Peak ground acceleration:Depth to water table (insitu):NCEER (1998)NCEER (1998)Based on Ic value7.100.665.50 ftDepth to water table (erthq.):Average results interval:Ic cut-off value:Unit weight calculation:Use fill:Fill height:5.00 ft32.60Based on SBTYes2.00 ftFill weight:Transition detect. applied:Kσ applied:Clay like behavior applied:Limit depth applied:Limit depth:120.00 lb/ft3YesNoSands onlyNoN/APA2022-0155
This software is licensed to: SA Geotechnical, Inc.CPT name: CPT-1CRR plotFILLHAND AUGERCRR & CSR0.60.40.20Depth (ft)20.52019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.543.532.521.510.5CRR plotDuring earthq.Liquefaction analysis overall plotsFS PlotHAND AUGERFILLFactor of safety21.510.50Depth (ft)20.52019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.543.532.521.510.5FS PlotDuring earthq.Liquefaction potentialFILLHAND AUGERLPI20151050Depth (ft)2019181716151413121110987654321Liquefaction potentialVertical settlementsFILLHAND AUGERSettlement (in)3210Depth (ft)2019181716151413121110987654321Vertical settlementsLateral displacementsFILLHAND AUGERDisplacement (in)0Depth (ft)20.52019.51918.51817.51716.51615.51514.51413.51312.51211.51110.5109.598.587.576.565.554.543.532.521.510.50Lateral displacementsCLiq v.3.4.1.4 - CPT Liquefaction Assessment Software - Report created on: 7/1/2022, 11:55:38 AM5Project file: P:\2022\22077-01 316 Grand Canal, Newport Beach\CLiq\22077-01.clqF.S. color schemeLPI color schemeInput parameters and analysis dataAnalysis method:Fines correction method:Points to test:Earthquake magnitude Mw:Peak ground acceleration:Depth to water table (insitu):NCEER (1998)NCEER (1998)Based on Ic value7.100.665.50 ftDepth to water table (erthq.):Average results interval:Ic cut-off value:Unit weight calculation:Use fill:Fill height:5.00 ft32.60Based on SBTYes2.00 ftFill weight:Transition detect. applied:Kσ applied:Clay like behavior applied:Limit depth applied:Limit depth:120.00 lb/ft3YesNoSands onlyNoN/AAlmost certain it will liquefyVery likely to liquefyLiquefaction and no liq. are equally likelyUnlike to liquefyAlmost certain it will not liquefyVery high riskHigh riskLow riskPA2022-0155
Appendix
F
PA2022-0155
E-1
APPENDIX F
GENERAL EARTHWORK AND GRADING SPECIFICATIONS
1.0 GENERAL
1.1 Intent: These General Earthwork and Grading Specifications are for the grading and earthwork shown on the approved grading plan(s) and/or indicated
in the geotechnical report(s). These Specifications are a part of the
recommendations contained in the geotechnical report(s). In case of conflict,
the specific recommendations in the geotechnical report shall supersede these
general Specifications. Observations of the earthwork by the project Geotechnical Consultant during grading may result in new or revised recommendations that could supersede these specifications or the
recommendations in the geotechnical report(s).
1.2 Geotechnical Consultant: Prior to commencement of work, the project owner shall employ a geotechnical consultant. The geotechnical consultant shall be
responsible for reviewing the approved geotechnical report(s) and accepting the
adequacy of the preliminary geotechnical findings, conclusions, and
recommendations prior to the commencement of grading.
Prior to commencement of grading, the Geotechnical Consultant shall review the "work plan" prepared by the Earthwork Contractor (Contractor) and schedule sufficient personnel to perform the appropriate level of observation,
mapping, and compaction testing.
During grading and earthwork operations, the Geotechnical Consultant shall
observe, map, and document the subsurface exposures to verify the
geotechnical design assumptions. If the observed conditions are found to be significantly different than the interpreted assumptions during the design phase,
the Geotechnical Consultant shall inform the owner, recommend appropriate
changes in design to accommodate the observed conditions, and notify the
review agency where required. Subsurface areas to be geotechnically observed, mapped, elevations recorded, and/or tested include natural ground after it has been cleared for receiving fill but before fill is placed, bottoms of all "remedial
removal" areas, all keyway bottoms, and benches made on sloping ground to
receive fill.
The Geotechnical Consultant shall observe the moisture-conditioning and processing of subgrade and fill materials and perform adequate relative
compaction testing of fill to determine the attained level of compaction and
assess if, in their opinion, if the work was performed in substantial compliance
PA2022-0155
E-2
with the geotechnical report(s) and these specifications. The Geotechnical Consultant shall provide test results to the owner on a routine and frequent
basis.
1.3 The Earthwork Contractor: The Earthwork Contractor (Contractor) shall be
qualified, experienced, and knowledgeable in earthwork logistics, preparation
and processing of ground to receive fill, moisture-conditioning and processing of fill, and compacting fill. The Contractor shall review and accept the plans,
geotechnical report(s), and these Specifications prior to commencement of
grading. The Contractor shall be solely responsible for performing the grading
in accordance with applicable grading codes, the project plans, and these
specifications. The Contractor shall prepare and submit to the owner and the Geotechnical Consultant a work plan that indicates the sequence of earthwork grading, the
number of "spreads" of work and the estimated quantities of daily earthwork
planned for the site prior to commencement of grading. The Contractor shall
inform the owner and the Geotechnical Consultant of changes in work
schedules and updates to the work plan at least 24 hours in advance of such changes so that appropriate observations and tests can be planned and
accomplished. The Contractor shall not assume that the Geotechnical
Consultant is aware of all grading operations.
The Contractor shall have the sole responsibility to provide adequate equipment and methods to accomplish the earthwork in accordance with the applicable
grading codes and agency ordinances, these Specifications, and the
recommendations in the approved geotechnical report(s) and grading plan(s).
If, in the opinion of the Geotechnical Consultant, unsatisfactory conditions,
such as unsuitable soil, improper moisture condition, inadequate compaction, insufficient buttress key size, adverse weather, etc., are resulting in a quality of
work less than required in these specifications, the Geotechnical Consultant
shall reject the work and may recommend to the owner that construction be
stopped until the conditions are corrected.
2.0 PREPARATION OF FILL AREAS
2.1 Clearing and Grubbing: Areas to be excavated and filled shall be cleared and
grubbed. Vegetation, such as brush, grass, roots, and other deleterious material,
man-made structures, and similar debris shall be sufficiently removed and properly disposed of in a method acceptable to the owner, governing agencies,
and the Geotechnical Consultant. Borrow areas shall be cleared and grubbed to
the extent necessary to provide a suitable fill material.
Concrete fragments that are free of reinforcing street may be placed in fills,
provided they are placed in accordance with Section 3 and 4. Earth fill material
PA2022-0155
E-3
shall not contain more than 1 percent of organic materials (by volume). No fill lift shall contain more than 5 percent organic matter. Nesting of organic
materials shall not be allowed.
If potentially hazardous materials are encountered, the Contractor shall stop work in the affected area, and a hazardous material specialist shall be informed immediately for proper evaluation and handling of these materials
prior to continuing to work in that area. As presently defined by the State of
California, most refined petroleum products (gasoline, diesel fuel, motor oil,
grease, etc.) have chemical constituents that are considered hazardous waste. As such, the indiscriminate dumping or spillage of such fluids may constitute a misdemeanor, punishable by fines and/or imprisonment, and shall not be
allowed.
The Geotechnical Consultant shall not be responsible for the identification or analysis of potentially hazardous materials; however, if observations, odors, or soil discoloration are suspect, the Geotechnical Consultant may request from
the owner the termination of grading operations until such materials are deemed
not hazardous as defined by applicable laws and regulations.
2.2 Evaluation/Acceptance of Fill Areas: All areas to receive fill, including removal and processed areas, key bottoms, and benches, shall be observed,
mapped, elevations recorded, and/or tested prior to being accepted by the
Geotechnical Consultant as suitable to receive fill. The Contractor shall obtain
a written acceptance from the Geotechnical Consultant prior to fill placement. A licensed surveyor shall provide the survey control for determining elevations of processed areas, keys, and benches.
2.3 Processing: Ground that has been declared satisfactory for support of fill by
the Geotechnical Consultant shall be scarified to a minimum depth of 6 inches. Ground that is not satisfactory shall be removed/overexcavated as specified in the following section. Scarification shall continue until soils are broken down
and free of large clay lumps or clods and the working surface is reasonably
uniform, flat, and free of uneven features that would inhibit uniform
compaction. After scarification, the surface should be moisture conditioned, as necessary, to achieve the proper moisture content and compacted in accordance with Section 4 of these specifications.
2.4 Overexcavation: In addition to removals and overexcavations recommended
in the approved geotechnical report(s) and the grading plan, soft, loose, dry,
saturated, spongy, organic-rich, highly fractured, or otherwise unsuitable
ground shall be overexcavated to competent ground as recommended by the Geotechnical Consultant during grading.
PA2022-0155
E-4
2.5 Benching: Fills to be placed on ground sloping steeper than 5H:1V (horizontal to vertical units) shall be stepped or benched. The lowest bench or key shall be a minimum of 15 feet wide and at least 2 feet deep, into competent material as
evaluated by the Geotechnical Consultant. Other benches shall be excavated a
minimum height of 4 feet into competent material or as otherwise
recommended by the Geotechnical Consultant. Fill placed on ground sloping
flatter than 5:1 shall also be benched or otherwise overexcavated to provide a flat subgrade for fill placement.
3.0 FILL MATERIAL
3.1 General: Material to be used as fill shall be essentially free of organic matter and other deleterious substances evaluated and accepted by the Geotechnical
Consultant prior to placement. Soils of poor quality, such as those with
unacceptable gradation, high expansion potential, or low strength shall be
placed in areas acceptable to the Geotechnical Consultant or mixed with other soils to achieve satisfactory fill material. 3.2 Oversize: Oversize material defined as rock, or other irreducible material with
a maximum dimension greater than 12 inches, shall not be buried or placed in
fill unless location, materials, and placement methods are specifically accepted
by the Geotechnical Consultant. Placement operations shall be such that nesting
of oversized material does not occur and that oversize material is completely surrounded by compacted or densified fill. Oversize material shall not be placed within 10 vertical feet of finish grade or within 2 feet of future utilities
or other underground construction.
3.3 Import: If importing of fill material is required for grading, proposed import material shall meet the requirements of Section 3.1 and/or requirements defined
in the project geotechnical report(s). The potential import source shall be given
to the Geotechnical Consultant at least 48 hours (2 working days) before import
begins so that suitability can be determined, and appropriate laboratory tests performed.
4.0 FILL PLACEMENT AND COMPACTION 4.1 Fill Layers: Approved fill material shall be placed in areas prepared to receive
fill (per Section 3.0) in near-horizontal layers not exceeding 8 inches in loose thickness. The Geotechnical Consultant may accept thicker layers if testing
indicates the grading procedures can adequately compact the thicker layers.
Each layer shall be spread evenly and mixed thoroughly to attain relative
uniformity of material and moisture throughout.
PA2022-0155
E-5
4.2 Fill Moisture Conditioning: Fill soils shall be watered, dried back, blended, and/or mixed, as necessary to attain a relatively uniform moisture content at or slightly over optimum. Maximum density and optimum soil moisture content
tests shall be performed in accordance with ASTM International (ASTM Test
Method D1557).
4.3 Compaction of Fill: After each layer has been moisture-conditioned, mixed,
and evenly spread, it shall be uniformly compacted to not less than 90 percent of maximum dry density (ASTM Test Method D1557). Compaction equipment
shall be adequately sized and be either specifically designed for soil compaction
or of proven reliability to efficiently achieve the specified level of compaction
and uniformity.
Compaction of Fill Slopes: In addition to normal compaction procedures
specified above, compaction of slopes shall be accomplished by backrolling of
slopes with sheepsfoot rollers at increments of 3 to 4 feet in fill elevation, or by other methods producing satisfactory results acceptable to the Geotechnical Consultant. Upon completion of grading, relative compaction of the fill, out to
the slope face, shall be at least 90 percent of maximum density per ASTM Test
Method D1557.
4.4 Compaction Testing: Field tests for moisture content and relative compaction
of the fill soils shall be performed by the Geotechnical Consultant. Location and frequency of tests shall be at the Consultant’s discretion based on field conditions encountered. Compaction test locations will not necessarily be
selected on a random basis. Test locations shall be selected to verify adequacy
of compaction levels in areas that are judged to be prone to inadequate
compaction (such as close to slope faces and at the fill/bedrock benches).
4.5 Frequency of Compaction Testing: Tests shall be taken at intervals required by the governing agency and as deemed necessary by the Geotechnical Consultant in order to adequately qualify the fill material. In general, it should be anticipated that tests will be taken at intervals not exceeding 2 feet in vertical rise
and/or 1,000 cubic yards of compacted fill, unless recommended otherwise by
the Geotechnical Consultant. In addition, test(s) shall be taken on slope faces and/or each 10 feet of vertical height of slope as deemed necessary by the Geotechnical Consultant. The Contractor shall assure that fill construction is such that the testing schedule can be accomplished by the Geotechnical
Consultant. The Contractor shall stop or slow down the earthwork construction
if these minimum standards are not met.
PA2022-0155
E-6
4.6 Compaction Test Locations: The Geotechnical Consultant shall document the approximate elevation and location of each compaction test. The Contractor
shall coordinate with the project surveyor to assure that sufficient grade stakes
are established so the Geotechnical Consultant can determine the test locations
with sufficient accuracy. At a minimum, two grade stakes within a horizontal distance of 100 feet and vertically less than 5 feet apart from potential test locations shall be provided. Alternatively, GPS units may be used to determine
the approximate location/coordinates of the field density tests.
5.0 SUBDRAIN INSTALLATION
Subdrain systems shall be installed in accordance with the approved geotechnical
report(s), the grading plan, and standard details. The Geotechnical Consultant may
recommend additional subdrains and/or changes in subdrain extent, location, grade, or
material depending on conditions encountered during grading. All subdrains shall be surveyed for line and grade after installation and prior to burial. Sufficient time should be allowed by the Contractor for these surveys. The Contractor should consider
videoing the subdrains shortly after burial to check proper installation and
functionality. The Contractor is responsible for the performance of subdrains.
6.0 EXCAVATION
Excavations, including over-excavation for remedial purposes, shall be evaluated by
the Geotechnical Consultant during grading. Remedial removal depths shown on
geotechnical report(s) and plans are estimates. The actual extent of removal shall be
determined by the Geotechnical Consultant based on the field evaluation of exposed conditions during grading. Where fill-over-cut slopes are to be graded, the cut portion
of the slope shall be made, evaluated, and accepted by the Geotechnical Consultant
prior to placement of materials for construction of the fill portion of the slope, unless
otherwise recommended by the Geotechnical Consultant.
7.0 TRENCH BACKFILLS
7.1 Contractor shall follow all OHSA and Cal/OSHA requirements for safety of
trench excavations.
7.2 Bedding and backfill of utility trenches shall be done in accordance with the
applicable provisions of Standard Specifications of Public Works Construction.
Bedding material shall have a Sand Equivalent greater than 30 (SE>30). The
bedding shall be placed to 1 foot over the top of the conduit and densified by
jetting. Backfill shall be placed and densified to a minimum 90 percent of maximum from 1 foot above the top of the conduit to the surface, except in
traveled ways (see Section 7.6 below).
PA2022-0155
E-7
7.3 Jetting of the bedding around the conduits shall be observed by the Geotechnical Consultant.
7.4 Geotechnical Consultant shall test the trench backfill for relative compaction.
At least one test should be made for every 300 feet of trench and 2 feet of fill,
unless required differently by the governing agency or the Geotechnical
Consultant.
7.5 Lift thickness of trench backfill shall not exceed those allowed in the Standard
Specifications of Public Works Construction unless the Contractor can
demonstrate to the Geotechnical Consultant that the fill lift can be compacted to
the minimum relative compaction by his alternative equipment and method.
7.6 Trench backfill in the upper foot measured from finish grade within existing or future traveled way, shoulder, and other paved areas (or areas to receive pavement) should be placed to a minimum 95 percent relative compaction.
PA2022-0155
Scale: 1”=10’100Geotechnical MapLegendBase map source: Bledsoe Giron Engineering & Survey Inc.QesEstuarine DepositsBeachlife Rentals LLC316 Grand CanalNewport Beach, CaliforniaProject Number: 22077‐01Date: June 2022Plate 1QesHA ‐2TD: 10’ HA‐1TD: 4.5’HA‐2TD: 10’Approximate Location of Hand‐Auger Boring, Showing Total Depth in Feet (3 Total)QesNORTHCPT‐1/HA‐3TD: 20.7’/10’Approximate Location of CPT and Hand‐Auger Boring, Showing Total Depth in FeetCPT‐1/HA‐3TD: 20.7’ Approximate Footprint of Proposed New StructurePA2022-0155