HomeMy WebLinkAboutX2021-0508 - Soilsv -w t I-VV%
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COAST GEOTECHNICAL, INC.
1200 W. Commonwealth Avenue, Fullerton, CA 92833 * Ph: (714) 870-1211 * Far,: (714) 870-1222 *E-mail: coastgeotec@sbcglobal.net
March 30, 2020
Ms. Diane Cumff
C/o Patterson Custom Homes
15 Corporate Plaza, Suite 150
Newport Beach, CA 92660
Reference:
W. 0. 578919-02
Subject: Rough Grade Compaction Report for Proposed
New Residence at 2731 Seaview Avenue,
Newport Beach, California
1. Geotechnical Engineering Investigation of Proposed New Residence at 2731 Seaview Avenue,
Newport Beach, California; by COAST GEOTECHNICAL, Inc., W.O. 578919-01, dated
August 2, 2019.
Dear Ms. Cuniff:
Forwarded herewith is the rough grade compaction report for the subject site. Our observations
and testing were performed periodically, as requested. The grading operation for the residential
development consisted of grading the residential pad area to provide uniformly compacted fill
soils for support of the residence. The grading operation was conducted from March 19, 2020
through March 23, 2020.
PLACEMENT OF FILL
Compacted fill material was placed to provide adequate support for the proposed structure.
The over -excavation of the building pad area extended into competent native material. The depth
of over -excavation was about three to four feet below original grade. The exposed surface was
scarified, moisture conditioned and compacted to a minimum of 90% relative compaction.
Subsequent fills were placed in six to eight inch loose lifts, moisture conditioned as needed, and
compacted to a minimum of 90% relative compaction by track rolling. The finish grade
elevations are near to approximately twelve inches below original grade.
A borrow pit was excavated to complete the finish grade of the pad area. The approximate
location of the borrow pit is shown on Plate 1, and extends roughly two feet below finish pad
grade. Backfill of the borrow pit should be properly compacted in six to eight inch lifts to a
minimum of 90% relative compaction and moisture conditioned as needed.
Limits of grading are shown on the attached Plate 1.
COAST GEOTECHNICAL, INC.
Ms. Diane Cuniff
W. 0.578919-02
Equipment used for the compaction of fill soils consisted of a Cat 953C Track loader. Soils were
moisture conditioned by a water hose, when needed. Earthwork was by JD Demolition and
Grading.
TESTING
Maximum density optimum moisture relationship determinations were performed for each soil
type encountered during grading operations. Test results were as follows:
Laboratory Standard: (ASTM:D-1557)
4 -inch diameter mold; 1/30 ft3 volume;
5 layers at 25 blows per layer;
10 lb. hammer dropped 18 inches
!!,!Te Brown to Orange Brown Silty Max. Dry Density, lb
Sand 8.5 1s/ft3
28.0
Compaction tests were performed a minimum of every two feet and/or 500 cubic yards of
compacted fill soils placed. These tests were performed in accordance with an ASTM test
method. The test results are summarized in Table 1. The approximate test locations are shown on
Plate 1. Areas not tested were probed to show adequate compaction.
FOUNDATIONS ON COMPACTED FILL
The residence shall be supported by conventional foundations.
Foundations for the proposed residence shall consist of continuous footings only placed a
minimum of 24 inches into compacted fill utilizing an allowable bearing value of 1,800 psf. This
value is for dead plus live load and may be increased 1/3 for total including seis
loads where allowed by Code, mic and wind
Minimum embedment depth shall be 24 inches below lowest adjacent grade and at least 18 inches
wide for three story construction. This value is for dead plus live load and may be increased by
one-third for total including seismic and wind loads where allowed by code.
Foundations for free standing retaining walls, property line walls maybe founded in compacted fill
footings only.
soils or competent native soils, utilizing an allowable bearing value of 1,500 psf, for continuous
Minimum geotechnical recommendations for foundation reinforcement are four #4 bars, two top
and two bottom. Structural requirements may be more stringent. Isolated footing shall be tied in
two directions with grade beams.
COAST GEOTECHNICAL, INC.
Ms. Diane Cuniff 3 W. 0.578919-02
Rough Grade Compaction Report March 30 2020
Foundation excavations shall be observed by a representative of COAST GEOTECHNICAL, Inc.
prior to placement of steel and concrete, to verify compliance with geotechnical recommendations.
LATERAL DESIGN
Lateral restraint at the base of footings and on slabs may be assumed to be the product of the
dead load and a coefficient of friction of 0.35. Passive pressure on the face of footings may also
be used to resist lateral forces. A passive pressure of zero at the surface of finished grade,
increasing at the rate of 300 pounds per square foot of depth to a maximum value of 3,000
pounds per square foot, may be used for compacted fill at this site. If passive pressure and
friction are combined when evaluating the lateral resistance, then the value of the passive
pressure should be limited to 2/3 of the values given above.
FLOOR SLABS
Where conventional foundation and slab on grade is utilized, the slab shall be supported on
engineered fill compacted to a minimum of 90% relative compaction.
Minimum geotechnical recommendations for on grade slab design are four inches actual thickness,
with #3 bars at twelve inches on center each way.
If the soils at grade become disturbed during construction, they shall be brought to 2-3% over
optimum moisture content and compacted to a minimum of 90% relative compaction prior to
placing concrete. COAST GEOTECHNICAL, Inc. will need to verify adequate mitigation.
The subgrade soil should be kept moist prior to casting the slab. However, if the soils at grade
become disturbed during construction, they should be brought to approximately optimum moisture
content and rolled to a firm, unyielding condition prior to placing concrete.
The capillary break material shall comply with the requirements of the local jurisdiction and shall
be a minimum of four inches in thickness and consist of gravel (1/2 -inch or larger clean aggregate).
A heavy filter fabric should be placed over the gravels prior to placement of the recommended
vapor retarder to minimize puncturing of the vapor retarder.
Slab areas should be underlain by a vapor retarder consisting of an engineered plastic film (as
described by ASTM:E-1745). A vapor barrier with a permeance of less than 0.01perms
(consistent with ACI 302.2R-06) such as 15 mil. Stego Wrap Vapor Barrier or equivalent should
be considered. The vapor barrier should be underlain by the above described capillary break
material and filter cloth (Mirafi 140N). The capillary break materials should be compacted to a
uniform condition prior to placement of the recommended filter cloth and vapor barrier. The
vapor barrier should be properly lapped and sealed and in contact with the slab bottom.
It is the responsibility of the contractor to ensure that the vapor barrier is not perforated prior to
placement of concrete and is installed in accordance the appropriate building codes and
manufacturer recommendations.
COAST GEOTECHNICAL, INC.
Ms. Diane Cuniff 4 W. 0. 578919-02
Rough Grade Compaction Report March 30 2020
SEISMIC DESIGN
Based on the ATC Hazards by location with Latitude 33.597577 and Longitude -117.876378 of
the site the following seismic design parameters are provided.
• Site Class = D
• Mapped 0.2 Second Spectral Response Acceleration, Ss = 1.703g
Mapped One Second Spectral Response Acceleration Sl = 0.624g
• Site Coefficient from Table 1613A.3.3(1), Fa = 1.0
• Site Coefficient from Table 1613A.3.3(2), Fv = 1.5
• Maximum Design Spectral Response Acceleration for short period, SMs = 1.703g
• Maximum Design Spectral Response Acceleration for one -second period, SMI = 0.936g
• 5% Design Spectral Response Acceleration for short period, SDS = 1.135g
• 5% Design Spectral Response Acceleration for one -second period, Spy = 0.624g
EXPANSIVE SOILS
Results of expansion tests indicate that the near surface soils have a very low expansion
potential.
UTILITY LINE BACKFILLS
All utility line backfills, both interior and exterior, shall be compacted to a minimum of
90% relative compaction and shall require testing at a maximum of two -foot vertical intervals.
Utility lines shall be placed at appropriate depths. Shallow pipes can be damaged by the forces
imposed by compacting backfill soils. If shallow pipes are not capable of withstanding the forces
of backfill compaction, slurry backfill will be recommended.
SOLUBLE SULFATES
Typical on-site soils showed a soluble sulfate content of 35 ppm. Based on the Table 4.3.1 of
ACI 318-05, concrete with Type II cement and a minimum compressive strength of 2,500 psi
may be utilized. The structural engineers design criteria may be more stringent. Concrete shall be
placed in accordance with appropriate codes.
HARDSCAPESLABS
Hardscape slab subgrade areas shall exhibit a minimum of 90% relative compaction and shall
near optimum moisture content to a depth of at least two feet. Deeper removal and compaction
may be required if unacceptable conditions are encountered. These areas require testing just prior
to placing concrete. Concrete slabs shall be a minimum of four inches actual thickness with #3
bars on 18 inch centers each way.
COAST GEOTECHNICAL, INC.
Ms. Diane Cuniff 5 W. O. 578919-02
Rough Grade Compaction Report _. March 30. 2020
DRAINAGE
Positive drainage should be planned for the site. Drainage should be directed away from
structures via non -erodible conduits to suitable disposal areas. The structure should utilize roof
gutters and down spouts tied directly to yard drainage.
Unlined flowerbeds, planters, and lawns should not be constructed against the perimeter of the
structure. If such landscaping (against the perimeter of a structure) is planned, it should be
properly drained and lined or provided with an underground moisture barrier. Irrigation should
be kept to a minimum.
While the current CSC recommends 5% slope away from structures for landscape areas, 2%
slope is allowable where justified. Our justification is the use of roof drains tied into area drains,
the use of area drains, and site grading, which will mitigate the potential for moisture problems
beneath a slab on grade. Hardscape areas shall be sloped a minimum of 2% where within ten feet
of the residence unless allowed otherwise by the building official
We do not recommend the use of infiltration best management practice (BMP) such as
bottomless trench drains, infiltration trenches, infiltration basins, dry wells, permeable
pavements or similar systems designed primarily to percolate water into the subsurface soils
within five feet of foundations. If infiltration system cannot be located away from foundations,
from a geotechnical viewpoint surface drainage should be directed to the street or alley.
The WQMP requirement shall be addressed by the Civil Engineer
POST -GRADING SERVICES
During construction of the residence, it is recommended, and at times required by the regulatory
agency, the following be observed and/or tested by the geotechnical engineer:
• Excavation of foundations
• Backfill of interior slab areas
• Backfill of interior trenches
• Slab subgrade testing prior to placement of the capillary break material
Backfill of exterior utility trenches
• Hardscape subgrade
It is the responsibility of the developer to schedule the required observations and testing.
REGULATORY COMPLIANCE
I hereby certify that the subject grading was observed by a representative from this office, and
the work was done in full compliance with the Grading Ordinance of the City of Newport Beach
COAST GEOTECHNICAL, INC.
Ms. Diane Cuniff 6 W. O. 578919-02
Rough Grade Compaction Report March 30 2020
and in accordance with the best accepted practices of the applicable chapter of the California
Building Code.
All cuts, fills or processing of original ground under the purview of this report have been
completed under the observation of and with selective testing by COAST GEOTECHNICAL,
INC. and found to be in compliance with the Grading Code of the City of Newport Beach. The
completed work has been observed by COAST GEOTECHNICAL, INC., and is considered
adequate for the development. Our findings were made and recommendations prepared in
accordance with generally accepted professional engineering practices, and no further warranty
is implied nor made.
This report is subject to review by the controlling authorities for this project.
We appreciate this opportunity to be of service to you.
Respectfully submitted:
COAST GEOTECHNICAL, INC.
�._
Ming-Tarng Chen
RCE 54011
COAST GEOTECHNICAL, INC.
Ms. Diane Cuniff 7 W. O. 578919-02
Rough Grade Compaction Report March 30 2020
COMPACTION TEST RESULTS
TABLE 1
Test
No.
Location
Below
Proposed
Grade (ft)
Moisture
Content
%
Dry UnitSod
Weight
(lbS/ft')
Type
Relative
Compaction
%
Date
1
Pad Area
3.03.5
8.5
119.3
I
93.2
3/19/20
2
Pad Area
3.03.5
8.8
118.9
I
92.9
3/19/20
3
Pad Area
1.52.0
8.5
116.4
I
90.9
3/19/20
4
Pad Area
3.03.5
8.9
118.8
I
92.8
3/20/20
5
Pad Area
3.03.5
8.5
117.4
I
91.7
3/20/20
6
Pad Area
1.52.0
8.7
118.3
I
92.4
3/20/20
7
Pad Area
F.G.
11.0
118.8
I
92.8
3/23/20
8
Pad Area
F.G.
10.5
119.2
I
93.1
3/23/20
9
Pad Area
F.G.
12.0
119.3
I
93.2
3/23/20
F.G.: Finish Grade
COMPACTION TEST LOCATIONS
U, Scale: V a 16'
4
3
9
W"! Approximate
6� II Limits of Grading
Approximate
3 Compaction
Test Location
Pit
Goldenrod Avenue
Rough Grade Compaction Report Work Order 578919-02
2731 Seaview Avenue
Newport Beach, California Plate No. 1
COAST GEOTECHNICAL,, INC.
ling
"NMI
Ito 9
j
01
Approximate
3 Compaction
Test Location
Pit
Goldenrod Avenue
Rough Grade Compaction Report Work Order 578919-02
2731 Seaview Avenue
Newport Beach, California Plate No. 1
COAST GEOTECHNICAL,, INC.
COAST GEOTECHNICAL, INC.
1200 West Commonwealth Avenue, Fullerton, CA 92833 Ph: 714-870-1211 Fax: 714-870-1222 e-mail: coastgeotec@sbeglobat.net
November 10, 2021
Ms. Diane Cuniff
C/o Patterson Custom Homes
15 Corporate Plaza Suite 150
Newport Beach, CA 92660
References:
W.O. 578919-03
Subject: Final Soils Report for 2731 Seaview Avenue,
Newport Beach, California
Geotechnical Engineering Investigation of Proposed New Residence at 2731 Seaview Avenue,
Newport Beach, California; by COAST GEOTECHNICAL, Inc., W.O. 578919-01, dated August
2, 2019.
2. Rough Grade Compaction Report for 2731 Seaview Avenue, Newport Beach, Califomia; by
COAST GEOTECHNICAL, Inc., W.O. 578919-02, dated March 30, 2020.
Dear Ms. Cuniff
In accordance with your request, this final soils report has been prepared to address geotechnical
observations and testing performed since completion of rough grading. This report addresses
requested observations and testing. Copies of our daily reports are maintained in our files.
FOUNDATION EXCAVATIONS
The foundation excavations for the residence were observed on March 1, 2020. The foundation
excavations were found to be acceptable at the time of this observation.
INTERIOR SLAB SUBGRADE AND TRENCH BACKFILLS
The interior slab subgrade and trench backfill was observed on March 20, 2020. Probing and
testing of the interior residential slab area indicated acceptable geotechnical conditions for support
of the proposed slab, at the time of our final observation.
HARDSCAPE
Subgrade of the patio, front entry walkway, northern side walkway and garage entry was observed
from August 11, 2021 to November 2, 2021. Probing and testing of the requested hardscape area
subgrades, indicated acceptable geotechnical conditions for support of the proposed hardscape.
COAST GEOTECHNICAL, INC.
Ms. Diane Cuniff 2 W.O. 578919-03
Final Soils Report November 10 2021
�IUGM
It is the opinion of COAST GEOTECHNICAL, INC. that the summarized geotechnical conditions
approved by this office are in compliance with project geotechnical reports and Newport Beach
building codes. The final grades appear to conform to approved plans.
We appreciate this opportunity to be of service to you.
Respectfully submitted:
COAST GEOTECHNICAL, INC.
Ming-Tarng Chen
RCE 54011 //oa
No. 54011 1�
Exp.12131121
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