HomeMy WebLinkAboutX2018-1437 - SoilsX2018-1437
507 Cornc4ion Ave
R MCCARTHY
CONSULTING, INC
October 9, 2018
507 Carnation Partners, LLC File No: 8229-10
180 N. Glendora Avenue, Suite 102 Report No: 20180911-1
Glendora, California 91741
Subject: Earthwork Observation/Testing Report
Proposed Residential Construction
507 Carnation Avenue
Corona del Mar, California
References: See attached list
This report presents the results of our observation and testing services performed during the
grading of the property located at 507 Carnation Avenue in Corona del Mar, California. The
purpose for our geotechnical services was to observe and document the grading operations as
part of the development of a graded pad area for proposed residential construction. Based on
our observations, and review of the test results, it is our opinion that the grading was
performed in substantial conformance with the City of Newport Beach and project grading
requirements.
SITE DESCRIPTION
The subject property is located on the northwest side of Carnation Avenue between 2nd Avenue
and 3rd Avenue in Corona del Mar, California. The property is flanked to the northwest by an
alley, by residential lots on the northeast and southwest side, and by Carnation Avenue on the
southeast side.
PROJECT DATA
Site: 507 Carnation Avenue
Corona del Mar, California
Owner: 507 Carnation Partners, LLC
General Contractor: Building Worx Development, LLC
Civil Engineer: Forkert Engineering & Surveying, Inc.
Regulatory Agency: City of Newport Beach
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
Phone 949 629 2539 1 Email info@Rmccarthyconsulting.com
October 9, 2018 File No: 8229-10
Report No: 20180911-1
Page: 2
Gradino Contractor: JD Demolition and Grading, Inc.
Grading Plans: "Precise Grading Plan", Forkert Engineering & Surveying, Inc., May 8,
2018, Scale 1" = 6', Sheets C-1 through C-4
Geotechnical Observation Period: September 6, 2018, through September 10, 2018
GRADING AND EARTHWORK
A. General
The former site structures, improvements and vegetation were demolished and cleared
from the property prior to and during grading. The site excavation exposed terrace
deposits and some near surface residual soils. Terrace deposits were encountered
essentially at the surface within the building pad excavations. Site conditions were
therefore generally as expected based on preliminary exploration as reported in the
attached references. A septic tank or cistern was encountered in the planned garage pad
and consisted of a 16 foot deep, round, block lined pit.
B. Preparation of Existing Ground
Within the building pad area, ground preparation consisted of overexcavation of existing
earth materials to expose competent terrace deposits materials. Terrace deposits
generally consisted of red -brown to dark brown silty clay, clayey silt and sandy clay. The
removal depths were at least 3 feet and exposed competent native terrace deposits at
the minimum depth within the graded area. Incidental, shallow, undocumented fill
materials and residual soils, where encountered, were removed as part of the grading
within the building area. An abandoned septic pit measuring 16 feet deep was
encountered near the northeast corner of the lot. The top of the septic pit was removed
and backfilled with approximately 6 cubic yards of slurry to within 3.5 feet from the
finished grade. The location of the abandoned septic pit is shown on the attached
Geotechnical Plot Plan, Figure 1.
Following removals, the in-place, exposed materials were observed and probed. Exposed
materials were determined to be suitable for support of fill soils.
C. Fill Placement and Compaction
Prior to placement of fill, the exposed surface was scarified, moisture conditioned, and
compacted to a minimum of 90 percent relative compaction. The on-site soil was
brought to near optimum moisture content, mixed, spread in 6- to 8 -inch loose lifts, and
compacted. Subsequent lifts were similarly placed and compacted. Test results indicate
that the recommended compaction, as determined by ASTM D1557, was achieved. The
maximum depth of fill placed was on the order of 3.5 feet in the building pad.
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
October 9, 2018
File No: 8229-10
Report No: 20180911-1
Page: 3
Fill material consisted of on-site silty clay, sandy clay and clayey sands generated from
on-site materials.
Equipment used for compaction included a CAT 953C track loader and a fire hose.
Based on the results of our field density testing, it is our opinion that adequate
compaction was achieved. Density tests were performed in accordance with ASTM
D1556 (Sand Cone Method) and/or ASTM D6938 (Nuclear Gauge Method). Field Density
Test Results are tabulated in Table 1, Results of Field Density Tests. The approximate
locations of density tests are on the Geotechnical Plot Plan, Figure 1.
Representative samples of the on-site soils used as fill were returned to the laboratory
for testing. Laboratory tests for maximum density and optimum moisture content were
performed in accordance with ASTM D1557 (the Five Layer Method). The results are
presented in Table 2, Laboratory Maximum Dry Density/Optimum Moisture Relationship.
Testing was performed on representative areas to render a professional opinion as to
the compaction of fill materials. It is our opinion that sufficient testing was performed to
arrive at the conclusions stated herein; however, this is an opinion and is not a warranty
that all fill materials are at 90 percent relative compaction.
CONCLUSIONS AND RECOMMENDATIONS
General
Based upon field observations and test results, it is our opinion that grading and compaction
described herein was accomplished in accordance with the project requirements and the
grading requirements of the City of Newport Beach. Field density testing indicated that a
minimum of 90 percent relative compaction was achieved at the locations tested as part of the
building pad and site grading.
Based on the observations and testing as described herein, the fill materials placed within the
building pad area at the site are considered suitable for the intended use. Laboratory tests
indicated that the on-site fill soils have a medium expansion potential (EI = 79). Fill soils were
determined to have low sulfate levels.
The contractor should verify that the finished pad grade is at an appropriate level for the
installation of the slab and subslab materials.
Drairl and Drainage Devices
The performance of the planned foundation and improvements is dependent upon maintaining
adequate surface drainage both during and after construction. The ground surface around
foundations and improvements should be graded so that surface water will not collect and
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
October 9, 2018
File No: 8229-10
Report No: 20180911-1
Page: 4
pond. The impact of heavy irrigation can artificially create perched water conditions. This may
result in seepage or shallow groundwater conditions where previously none existed.
Attention to surface drainage and controlled irrigation will significantly reduce the potential for
future problems related to water infiltration. Irrigation should be well controlled and minimized.
Seasonal adjustments should be made to prevent excessive watering.
Sources of uncontrolled water, such as leaky water pipes or drains, should be repaired if
identified.
The Owner should be aware of the potential problems that could develop when drainage is
altered through construction of retaining walls, paved walkways, utility installations or
other various improvements. Ponded water, incorrect drainage, leaky irrigation systems,
overwatering or other conditions that could lead to unwanted groundwater infiltration must be
avoided.
Area drains should be installed in all planter and landscape areas. Planter surfaces should be
sloped away from building areas in accordance with code requirements or at least 5 percent.
Roof drainage should be tight -lined into the area drain system or carried to outlets away from
building foundations. Planters should not be allowed adjacent to foundations unless they are
lined with a bottom barrier installed with a minimum 5 percent gradient away from foundations
and drained with a subdrain.
Irrigation water should be controlled for the landscape areas in a way that maintains uniform
moisture conditions around and below the building slab and footings. Changes in exterior
moisture will promote heave and desiccation in the soil supporting foundations and must
therefore be avoided. Installation of concrete patios and walkways adjacent to the building is
recommended due to the potentially expansive on-site soil conditions. 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 have a
very low permeability. 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. On-site soils are a mix
of silty clay and sandy clay and are relatively impermeable. The bedrock at a depth of 6 to 7
feet below the surface may also act as a relatively impermeable barrier.
Foundation Design - Desion of Footings
It is anticipated that foundation elements for the residence will bear in recompacted fill and will
utilize conventional footings and grade beams. The near surface soils exhibit a medium
expansion potential. The on-site soil conditions were generally as expected based on
preliminary findings. The foundation recommendations are therefore presented below without
revision.
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
October 9, 2018
General
File No: 8229-10
Report No: 20180911-1
Page: 5
It is anticipated that foundation elements for the residence will bear in recompacted fill
and will utilize footings and grade beams. The near surface materials are expected to
exhibit a medium expansion potential (EI = 79).
a. Foundations
The allowable bearing capacity for conventional spread and/or continuous footings
having a minimum width of 15 -inches and founded a minimum of 24 -inches below
the lowest adjacent grade in recompacted fill should not exceed 1,500 pounds per
square foot. This value may be increased by one-third for short-term wind or seismic
loading. All pad footings should be tied by grade beams in not less than two
directions. A continuous perimeter footing to a minimum depth of 24 -inches is
recommended to reduce lateral moisture transfer below the foundation and slab. A
grade beam to a depth of 24 -inches should also be poured along garage door
openings. Actual footing depths and widths should be governed by CBC
requirements and the structural engineering design.
b. Lateral Resistance
Lateral loads for foundation and slab design may be resisted by passive pressure
forces developed in front of footings and by lateral sliding resistance acting at the
base of foundation elements. These load bearing values are to be used with the
allowable stress design load combinations specified in CBC Section 1605.3. An
allowable lateral bearing pressure of 150 pounds per square foot per foot of depth
equivalent fluid pressure may be assumed. Resistance to sliding can be calculated
using a cohesion value of 130 pounds per square foot of contact area to a maximum
value of one-half the dead load. These values may be used in combination per 2016
CBC, Section 1806.3.1. The values for lateral load resistance may be increased by
one-third for the alternative basic load combinations of CBC, Section 1605.3.2, that
include wind or seismic loads.
c. Footing Reinforcement
Two No. 5 bars should be placed at the top and two at the bottom of continuous
footings in order to resist potential movement due to various factors such as
subsurface imperfections and seismic shaking.
Slab -On -Grade Construction
The on-site soils are expected to exhibit a medium expansion potential based on our site
investigation. Conventional slabs should be at least 5 -inches thick (actual). Slab reinforcement
should be determined by the Structural Engineer. As a minimum, reinforcement should consist
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
October 9, 2018
File No: 8229-10
Report No: 20180911-1
Page: 6
of No. 4 bars placed 12 -inches on center in both directions at the center -height of the slab.
Slabs should be underlain by 4 -inches of open -graded gravel. Slab underlayment is deferred to
the Project Architect; however, in accordance with the American Concrete Institute, we suggest
that slabs be underlain by a 15 -mil thick vapor retarder/barrier (Stego Wrap or equivalent)
placed over the gravel in accordance with the requirements of ASTM E1745 and E1643. Slab
subgrade soils should be pre -saturated to 130 percent of optimum moisture to a depth of 24 -
inches below grade as verified by the Soils Engineer prior to placement of the vapor retarder.
All subgrade materials should be geotechnically approved prior to placing the gravel for the slab
underlayment.
Exterior flatwork elements should be a minimum 5 -inches thick (actual) and reinforced with No.
4 bars at 12 -inches on -center both ways. Subgrade soils should be pre-soaked as indicated
above prior to placing concrete.
Hardscape Design and Construction
Hardscape improvements may utilize conventional foundations in compacted fill. Such
improvements should be designed in accordance with the foundation recommendations
presented above and should consider the expansion potential of the on-site soils. Cracking and
offsets at joints are likely; however, occurrence may be minimized by appropriate drainage and
the use of thickened edge beams to limit moisture transfer below slabs.
Concrete flatwork should be divided into as nearly square panels as possible. Joints should be
provided at maximum 6 feet intervals to give articulation to the concrete panels (shorter
spacing is recommended if needed to square the panels).
Landscaping and planters adjacent to concrete flatwork should be designed in such a manner as
to direct drainage away from concrete areas to approved outlets. Planters located adjacent to
principle foundation elements should be sealed and drained; this is also important if they are
near retaining wall backfills.
Flatwork elements should be a minimum 5 -inches thick (actual) and reinforced with No. 4 bars
12 -inches on center both ways. Subgrade soils should be presaturated to 130 percent of
optimum moisture to a depth of 24 -inches and geotechnically approved prior to placement of
concrete. Maintaining the graded moisture content and preventing desiccation of the subgrade
soils through periodic watering of the exposed soils is recommended.
Foundation Excavations
All excavations should be observed by the Geotechnical Engineer prior to placement of forms,
reinforcement, and concrete for verification of conformance with the intention of these
recommendations. All excavations should be trimmed neat, level, and square. All loose or
sloughed material should be removed prior to the placement of concrete. Materials from footing
excavations should not be spread in house slab -on -grade areas.
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
October 9, 2018 File No: 8229-10
Report No: 20180911-1
Page: 7
Concrete Construction Components in Contact with Soil
The on-site soils are expected to have a negligible soluble sulfate content based on the results
of laboratory testing, which indicated less than 0.10 percent soluble sulfate. Ordinary Type II
cement is therefore anticipated to be suitable for concrete in contact with the subgrade soils. A
minimum design strength of 4,000 psi and water to cement ratio of 0.5 maximum may be
considered for flooring moisture considerations, but is not required for sulfate considerations. It
is recommended that a concrete expert be retained to design an appropriate concrete mix to
address the structural requirements. In lieu of retaining a concrete expert, it is recommended
that the 2016 CBC, Section 1904 and 1905, be utilized which refers to ACI 318.
Metal Construction Components in Contact with Soil
Test results indicate a moderate to severe potential for corrosion. Metal rebar encased in
concrete, iron pipes, copper pipes, lift shafts, air conditioner units, etc., that are in contact with
soil or water that permeates the soil should be protected from corrosion that may result from
salts contained in the soil. Recommendations to mitigate damage due to corrosive soils, if
needed, should be provided by a qualified corrosion specialist. The corrosivity testing is
presented in the attached Table 4.
Construction Considerations
During the grading process and prior to the complete construction of permanent drainage
controls, it shall be the responsibility of the contractor to provide good drainage and prevent
ponding of water and damage to adjoining properties, slopes or to finished work on the site.
After the geotechnical engineer has finished observations of the completed grading, no further
excavations and/or filling shall be performed without the approval of the geotechnical engineer.
Utility Trench Backfill
It is the Owner's and Contractor's responsibility to inform subcontractors of these requirements
and to notify R McCarthy Consulting, Inc., when backfill placement is to begin. It has been our
experience that trench backfill requirements are rigorously enforced by the local agencies. The
on-site soils are anticipated to be generally suitable for use as trench backfill; however, they
may be difficult to mix and compact to a uniform condition. The use of imported backfill is
sometimes more efficient when clay soil materials are at high moisture contents. Fill materials
should be placed at near optimum moisture content and compacted under the observation and
testing of the Soil Engineer. The minimum dry density required for compacted backfill material
is 90 percent of the maximum dry density as determined by ASTM D1557-12.
The final utility line backfill report from the Project Soil Engineer shall include an approval
statement that the backfill is suitable for the intended use.
R McCarthy Consulting, Inc,
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
October 9, 2018
File No: 8229-10
Report No: 20180911-1
Page: 8
Barriers should be installed as necessary for any permeable backfills parallel or under building
foundations in order to limit water transmission below the slab and footings.
Observation and Testing
Geotechnical observation and testing during construction is required to verify proper removal of
unsuitable materials, check that foundation excavations are clean and founded in competent
material, to test for proper moisture content and proper degree of compaction of fill, to test and
observe placement of wall and trench backfill materials, and to confirm design assumptions. It
is noted that the CBC requires continuous verification and testing during placement of fill, pile
driving, and pier/caisson drilling.
A R McCarthy Consulting, Inc., representative shall observe the site at intervals appropriate to
the phase of construction, as notified by the Contractor, in order to observe the work completed
by the Contractor. Such visits and observation are not intended to be an exhaustive check or a
detailed inspection of the Contractor's work but rather are to allow R McCarthy Consulting, Inc.,
as an experienced professional, to become generally familiar with the work in progress and to
determine, in general, if the grading and construction is in accordance with the
recommendations of this report.
R McCarthy Consulting, Inc., shall not supervise, direct, or control the Contractor's work.
R McCarthy Consulting, Inc., shall have no responsibility for the construction means, methods,
techniques, sequences, or procedures selected by the Contractor, the Contractor's safety
precautions or programs in connection with the work. These rights and responsibilities are
solely those of the Contractor. R McCarthy Consulting, Inc., shall not be responsible for any acts
or omission of any entity performing any portion of the work, including the Contractor,
subcontractor, or any agents or employees of any of them. R McCarthy Consulting, Inc., does
not guarantee the performance of any other parties on the project site, including the
Contractor, and shall not be responsible for the Contractor's failure to perform its work in
accordance with the Contractor documents or any applicable law, codes, rules or regulations.
Construction phase observations are beyond the scope of this investigation and budget and are
conducted on a time and material basis. The responsibility for timely notification of the start of
construction and ongoing geotechnically involved phases of construction is that of the Owner
and Contractor. We request at least 48 hours' notice when such services are required.
Geotechnical Observation/Testing Activities Durina Grading and Construction
The Geotechnical Consultant should be notified to observe and test the following activities
during grading and construction:
• To observe proper removal of unsuitable materials;
• To observe the bottom of removals for all excavations for the building pad grading,
trenching, exterior site improvements, etc.;
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
October 9, 2018
File No: 8229-10
Report No: 20180911-1
Page: 9
• To observe side cut excavations for retaining walls, trenches, etc.;
• To test for proper moisture content and proper degree of compaction of fill;
• To check that foundation excavations are clean and founded in competent material prior
to and after pre-soaking of the slab subgrade soils;
• To check the slab subgrade materials prior to placing the gravel, vapor barrier and
concrete;
• To check retaining wall subdrain installation when the pipe is exposed and before it is
covered by the gravel and fabric; and again after the gravel and fabric have been
placed;
• To test and observe placement of wall backfill materials;
• To test and observe placement of all trench backfill materials;
• To test and observe patio, driveway apron and sidewalk subgrade materials: do not
pour any concrete flatwork without an approval memo from our office.
• To observe any other fills or backfills that may be constructed at the site.
It is noted that this list should be used as a guideline. Additional observations and testing may be
required per local agency, code, project, Contractor and geotechnical requirements at the time of
the actual construction.
Subsequent Grading Operations
Prior to the commencement of additional grading operations on-site including items such as
utility trenches, hardscape, drainage improvements, retaining wall drain installation and backfill,
etc., we recommend to the Owner that our office be notified to provide appropriate
recommendations and observation and testing services as required.
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
October 9, 2018
File No: 8229-10
Report No: 20180911-1
Page: 10
Our description of grading operations, as well as observations and testing, has been limited to
those grading operations observed between September 6, 2018, and September 10, 2018. This
report does not include line and grade survey results. Elevations and locations used in this
report are estimated based on field surveys done by others.
The opinions rendered apply to conditions in the subject areas observed by us as of the date of
our indicated site visits. We are not responsible for any changes in the conditions that may
occur after that date and outside our purview. Our work is considered to be in accordance with
the usual standards of the profession and with local practice. No other warranty is expressed or
implied.
The opportunity to be of service is appreciated. If you have any questions, please call.
Respectfully submitted,
R MCCARTHY CONSULTING, INC.
Robe J. c?rthy,bG490
Geotechnical Engineer
Registration Expires 3-31-20
Date Signed: 10/9/18
Attachments: Table 1— Results of Field Density Tests
Table 2 — Laboratory Maximum Dry Density/Optimum Moisture Relationship
Table 3 — Expansion Test Results
Table 4 — Chemical Test Results
References
Figure 1 — Geotechnical Plot Plan
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
October 9, 2018 File No: 8229-10
Report No: 20180911-1
Page: 11
TABLE 1- RESULTS OF FIELD DENSITY TESTS
Test
No.
Test Date
Location
Approx.
Depth
Below
FG (feet)
Soil
Type
Moisture
Content
(%)
Dry
Density
(pcf)
Relative
Compaction
(%)
1
9/6/2018
Building Pad
-2
2
18.7
110.0
90
2
9/6/2018
Building Pad
-2
3
17.0
106.1
92
3
9/6/2018
Building Pad
-2
2
15.6
110.4
91
4
9/6/2018
Building Pad
-1
3
20.1
104.7
91
5
9/6/2018
Building Pad
-2.5
3
21.7
104.1
91
6
9/6/2018
Building Pad
FG
3
17.5
105.4
92
7
9/7/2018
Building Pad
-3
3
19.0
106.6
93
8
9/7/2018
Building Pad
-1
3
17.9
105.0
91
9
9/7/2018
Building Pad
-0.5
2
16.8
111.9
92
10
9/7/2018
Building Pad
-0.5
2
16.0
113.5
93
11
9/7/2018
Building Pad
-0.5
3
15.7
109.0
95
12
9/7/2018
Building Pad
-0.5
3
17.9
108.6
94
13*
9/10/2018
Building Pad
FG
2
10.8
116.0
95
14*
9/10/2018
Building Pad
FG
2
14.6
113.1
93
Notes: *indicates Sand Cone Test; all other tests Nuclear Gauge Method
FSG = Finished Subgrade SG = Subgrade Rt # indicates retest of failing test
TABLE 2 - LABORATORY MAXIMUM DRY DENSITY/
OPTIMUM MOISTURE RELATIONSHIP
ASTM D1557-12
Soil
Optimum
Maximum Dry
Type
Description
Moisture
Density (per
Content (%)
1
Dark olive brown, silty CLAY/clayey SAND
11.0
124
2
Dark, grey -brown sandy CLAY/clayey SAND
12.0
121.5
3*
Dark brown Silty CLAY
15.0
115
4*
Brown Silty CLAY with Sand
16.0
113
5*
Red Brown clayey SAND/sandy CLAY
10.0
119
*Test results from Reference 12
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
October 9, 2018 File No: 8229-10
Report No: 20180911-1
Page: 12
TABLE 3 — EXPANSION INDEX TEST RESULTS
(ASTM D4829)
Sample
Location
Description
Expansion
Index
Expansion Potential
Bldg Pad
Dark brown silty CLAY
79
Medium
TABLE 4 — CHEMICAL TESTS
A series of chemical tests were performed. The testing was performed by HDR as indicated
below.
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
Soluble Sulfates
Soluble
Min. Resistivity
Test
Soil
(ppm)
Chlorides (ppm)
(ohm -cm)
Location
Classification
pH
CA. 417
CA. 422
CA. 643
HA -1@0-5'
CUSC
7.0
28
11
1160
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
October 9, 2018
File No: 8229-10
Report No: 20180911-1
Page: 13
1. Apex Land Surveying, Inc., 2017, "Topographic Map, 507 Carnation Avenue, Corona del
Mar, CA 92625, APN: 459-093-15," 12/4/17, Scale: 1" = 8', Sheet 1 of 1.
2. California Building Code, 2016 Edition.
3. Coast Geotechnical, Inc., 2011, "Geotechnical Engineering Investigation for Proposed
New Residence at 501 Carnation Avenue, Newport Beach, California," W.O. 426811-01,
for Mr. David Close, Spinnaker Development, LLC, 428 32nd Street, Newport Beach, CA
92660, November 4.
4. Coast Geotechnical, Inc., 2013, "Geotechnical Engineering Investigation of Proposed
New Residence at 511 Carnation Avenue, Newport Beach, California, W.O. 453213-01,
for La Jolla Breeze Capital c/o Mr. Steve Corrington, 836 Prospect Street, La Jolla, CA
92037," June 3.
5. Department of the Navy, 1982, NAVFAC DM -7.1, "Soil Mechanics, Design Manual 7.1,"
Naval Facilities Engineering Command.
6. EGA Consultants, 2017, "Final Grading Certificate, Hardscape Compaction, Utility Trench
Backfill at New Residential Duplex Property located at 607 Carnation Avenue, Corona del
Mar, California, City of Newport Beach, Permit No. 2688-2015, Project No. SC881.2,"
July 14.
7. Geo-Etka, Inc., 1999, "Preliminary Foundation Soils Exploration at 503 Carnation
Avenue, Corona del Mar, California, for The Ash Company, 14 Cameo Crest, Laguna
Niguel, California 92667," Job No: F-8829-99, April 19.
8. Morton and Miller, 1981, Geologic Map of Orange County, CDMG Bulletin 204.
9. Morton, D. M., Bovard, Kelly H., and Alvarez, Rachel M., 2004, "Preliminary Digital
Geological Map of the 30'X 60' Santa Ana Quadrangle, Southern California, Version 2.0,"
Open -File Report 99-172, Version 2.0 — 2004.
10. Morton, P. K., Miller, R. V., and Evans, J. R., 1976, "Environmental Geology of Orange
County, California: California Division of Mines and Geology," Open File Report 79-8 LA.
11. Morton, Douglas M., and Miller, Fred K., compilers, 2006, "Geologic Map of the San
Bernardino and Santa Ana 30'X 60' Quadrangles, California," U. S. Geological Survey
Open File Report 2006-1217.
12. R McCarthy Consulting, Inc., 2016, "Earthwork Observation/Testing Report, Custom
Home Residence, 607 Begonia Avenue, Newport Beach, California", File No: 8058-10,
Report No: 20160802-1, August 2.
13. R McCarthy Consulting, Inc., 2018, "Geotechnical Investigation, Proposed Residential
Construction, 507 Carnation Avenue, Corona del Mar, California," File No: 8229-00,
Report No: 20180315-1, April 9.
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
m U
7
U Z
r. 3nrvanv rvoTivrvav� ----' d CC
` L 0
c
LL a
L
co
❑)� d c
1j m d m
S
O � N L @ C co
IE
S G W
s O O
o .o �
M K N
a a a >
e W 6 QU
a m
r r
II,
1 1 i i O
I
p ��I 11V —
a3llV I O
E� t3 N
(l a
R MCCARTHY
CONSULTING, INC
December 20, 2019
507 Carnation Partners, LLC File No: 8229-10
180 N. Glendora Avenue, Suite 102 Report No: R3-8229
Glendora, California 91741
Subject: Earthwork Observation/Testing Report
Project Final Report
Residential Construction
507 Carnation Avenue
Corona del Mar, California
Grading Permit No: X2018-2178
References: 1. R McCarthy Consulting, Inc., 2018, 'Earthwork Observation/Testing Report,
Residential Construction, 507 Carnation Avenue, Corona del Mar, California," File No.
8229-10, Report No. 20180115-2, October 9.
2. R McCarthy Consulting, Inc., 2018, "Geotechnical Investigation, Proposed
Residential Construction, 507 Carnation Avenue, Corona del Mar, California," File No:
8229-00, Report No: 20180911-1, April 9.
This report presents the results of our observation and testing services performed during the
construction -phase activities for the property located at 507 Carnation Avenue in Corona del
Mar, California. The purpose for our geotechnical services was to observe and document the
earthwork operations including footing excavations, trench backfills and hardscape subgrades at
the site. We understand that the earthwork is now complete and no further grading or
earthwork is to be done. This report may, therefore, be considered to be a final report of
earthwork observation and testing. Based on our observations, and review of the test results, it
is our opinion that the earthwork was performed in substantial conformance with the City of
Newport Beach and project grading requirements.
PROJECT DATA
Site: 507 Carnation Avenue
Corona del Mar, California
Owner/Developer: 507 Carnation Partners, LLC
General Contractor: Building Worx Development
Civil Engineer: Forkert Engineering & Surveying, Inc.
Regulatory Agency: City of Newport Beach
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
Phone 949 629 2539 1 Email info a rinccarthyconsulting.com
December 20, 2019 File No: 8229-10
Report No: R3-8229
Page: 2
Grading Contractor: ]D Demolition and Grading, Inc.
Grading Plans: "Precise Grading Plan", Forkert Engineering & Surveying, Inc., May 8,
2018, Scale 1" = 6', Sheets C-1 through C-4
Geotechnical Observation Period: September 6, 2018 through December 20, 2019
SITE DESCRIPTION
The subject property is located on the northwest side of Carnation Avenue between 2nd Avenue
and 3rd Avenue in Corona del Mar, California. The property is flanked to the northwest by an
alley, by residential lots on the northeast and southwest side and by Carnation Avenue on the
southeast side.
GRADING AND EARTHWORK
A. General
The observation and testing reported herein includes the footing excavations, slab
subgrade, trench backfills and hardscape subgrade.
B. Fill Placement and Compaction
Fill and backfill material consisted of on-site silty clay, clayey sand, sandy clay.
Equipment used for compaction included hand operated mechanical equipment and a
water hose.
• Building pad and site grading was observed and tested as previously reported in
Reference 1.
• Foundation and slab areas for the house structure were observed periodically
during the construction and approved from a geotechnical standpoint.
• Foundation excavations for the front right side (northeast) planter wall were
observed. An additional 12 -inches of concrete slurry was placed below the
planter footing to replace unsuitable soil and provide additional embedment.
• Interior plumbing trenches were backfilled with compacted on-site soil and
shading sand.
• The sewer trench was excavated between the house and alley and backfilled
with gravel and compacted on-site soil.
• The water line, electric and gas trenches were backfilled with shading sand and
compacted on-site soils.
• The hardscape subgrade was observed and tested and consisted of compacted
onsite soils.
The maximum depth of backfill placed was approximately 4.5 feet within the sewer
trench.
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
December 20, 2019
File No: 8229-10
Report No: 113-8229
Page: 3
Based on the results of our field density testing, it is our opinion that a minimum of
90 percent relative compaction was achieved within the areas tested. Density tests were
performed in accordance with ASTM D1556 (Sand Cone Method) and/or ASTM D6938
(the Nuclear Gauge Method). Areas of prepared subgrades, backfills and footing
excavations were also probed to check compaction. Field Density Test Results are
tabulated in Table 1, Results of Field Density Tests. The approximate locations of density
tests are included on the Geotechnical Plot Plan, Figure 1.
Representative samples of the site soils used as fill were returned to the laboratory for
testing. Laboratory tests for maximum density and optimum moisture content were
performed in accordance with ASTM D1557 (the Five Layer Method). The results are
presented in Table 2, Laboratory Maximum Dry Density/Optimum Moisture Relationship.
Testing was performed on representative areas to render a professional opinion as to
the compaction of fill materials. It is our opinion that sufficient testing was performed to
arrive at the conclusions stated herein; however, this is an opinion and is not a warranty
that all fill materials are at 90 percent relative compaction.
CONCLUSIONS AND RECOMMENDATIONS
A. General
Based upon field observations and test results, it is our opinion that grading and
compaction described herein was accomplished in accordance with the project
requirements and the grading requirements of the City of Newport Beach. Field density
testing indicated that a minimum of 90 percent relative compaction was achieved at the
locations tested.
Based on the observations and testing, the described fill and backfill materials placed at
the site are considered suitable for the intended use.
B. Drainage and Drainage Devices
The performance of the planned foundation and improvements is dependent upon
maintaining adequate surface drainage both during and after construction. The ground
surface around foundations and improvements should be graded so that surface water
will not collect and pond. The impact of heavy irrigation can artificially create perched
water conditions. This may result in seepage or shallow groundwater conditions where
previously none existed.
Attention to surface drainage and controlled irrigation will significantly reduce the
potential for future problems related to water infiltration. Irrigation should be well
controlled and minimized. Seasonal adjustments should be made to prevent excessive
watering.
Sources of uncontrolled water, such as leaky water pipes or drains, should be repaired if
identified.
R McCarthy Consulting, Inc.
23 Corporate Plaza, Suite 150, Newport Beach, CA 92660
December 20, 2019
File No: 8229-10
Report No: R3-8229
Page: 4
The Owner should be aware of the potential problems that could develop when drainage
is altered through construction of retaining walls, paved walkways, utility installations or
other various improvements. Ponded water, incorrect drainage, leaky irrigation systems,
overwatering or other conditions that could lead to unwanted groundwater infiltration
must be avoided.
C. Subsequent Grading Operations
Prior to the commencement any future on-site earthwork we recommend to the Owner
that a geotechnical engineer be notified to provide appropriate recommendations and
observation and testing services as required.
LIMITATIONS
Our description of grading operations, as well as observations and testing, has been limited to
those grading operations observed between September 6, 2018 and December 20, 2019. This
report does not include line and grade survey results. Elevations and locations used in this
report are estimated based on Feld surveys done by others.
The opinions rendered apply to conditions in the subject areas observed by us as of the date of
our final site visit. We are not responsible for any changes in the conditions that may occur
after that date and outside our purview. Our work is considered to be in accordance with the
usual standards of the profession and with local practice. No other warranty is expressed or
implied.
The opportunity to be of service is appreciated. If you have any questions, please call.
Respectfully submitted,
R MCCARTHY CONSULTING, INC.
Robert J—McCarthy, &6E 2490
Geotechnical Engineer
Registration Expires 3-31-20
Date Signed: 12/20/19
Attachments: Figure 1, Geotechnical Plot Plan
Table 1 — Results of Field Density Tests
Table 2 — Laboratory Maximum Dry Density/Optimum Moisture Relationship
R McCarthy Consulting, Inc.
23 Corpai ate Plaza, Suite 150, Newport t3each, CA 92660
December 20, 2019 File No: 8229-10
Report No: R3-8229
Page: 5
TABLE 1 - RESULTS OF FIELD DENSITY TESTS
Test
No.
Test Date
Location
Depth
(feet)
Soil
Type
Moisture
Content
(%)
DryRelative
Density
(Pcf)
Compaction
1
9/6/2018
Building Pad
-2
2
18.7
110.0
90
2
9/6/2018
Building Pad
-2
3
17.0
106.1
92
3
9/6/2018
Building Pad
-2
2
15.6
110.4
1 91
4
9/6/2018
Building Pad
-1
3
20.1
104.7
91
5
9/6/2018
Building Pad
-2.5
3
21.7
104.1
91
6
9/6/2018
Building Pad
FG
3
17.5
105.4
92
7
9/7/2018
Building Pad
-3
3
19.0
106.6
93
8
9/7/2018
Building Pad
_1
3
17.9
105.0
91
9
9/7/2018
Building Pad
-0.5
2
16.8
111.9
92
10
9/7/2018
Building Pad
-0.5
2
16.0
113.5
93
11
9/7/2018
Building Pad
-0.5
3
15.7
109.0
95
12
9/7/2018
Building Pad
-0.5
3
17.9
108.6
94
13*
9/10/2018
Building Pad
FG
2
10.8
116.0
95
14*
9/10/2018
Building Pad
FG
2
14.6
113.1
93
1
9/6/2018
Building Pad
-2
2
18.7
110.0
90
Notes: *indicates Sand Cone Test; all other tests Nuclear Gauge Method
Depth indicated is below finished subgrade
FG = Finished Grade RT = Retest
TABLE 2 - LABORATORY MAXIMUM DRY DENSITY/
OPTIMUM MOISTURE RELATIONSHIP
ASTM D1557
Soil
Optimum
Maximum Dry
Type
Description
Moisture
Density (pcfi)
Content (%)
1
Dark olive brown, silty CLAY/clayey SAND
11.0
124
2
Dark, grey -brown sandy CLAY/clayey SAND
12.0
121.5
3
Dark brown Silty CLAY
15.0
115
4
Brown Silty CLAY with Sand
16.0
113
5
Red Brown clayey SAND/sandy CLAY
10.0
119
R McCarthy Consulting, Inc.
23 Coiporate Plaza, SUIte 150, Newport Beach, CA 92660
}o
Iz
N Z
Q J
�I U
U z
o
�y 30N3�tl NOIltlNtitlp� -" � C U
Ln
a o y+
w
o
— L s
-Eo
o- h
III, 1 L N t6 N
r ISI O7 n
iql
O W
.3 Oi
II O I u 0� L
f, 06
I
•�` a .G
_ � LL��O Fty
�T
a I I 1 to
a i
v
I.+
a� ill8
c
m
<m IL
O
11
\�- S4
O d
IFd\b v E Q
\ o 0Q
V O
='
E E N
U1 (O l0 U
a3 A3Ttl �
O
Q Q Q a
z m
E
w � m