HomeMy WebLinkAboutMS 14-05; HOOVER MINOR SUBDIVISION; FINAL SOILS REPORT; 2021-07-19FINAL SOILS REPORT OF SEWER TRENCH BACKFILL
TRENCH RESURFACING, AND REPAIRS
HOOVER MINOR SUBDIVISION
ASSESSOR’S PARCEL NUMBER 206-150-12-00 AND ADAMS AVENUE
CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA 92008
CITY OF CARLSBAD PROJECT NO.: MS 14-05
FOR
MR. ROBERT DETRICH
1230 HOOVER STREET
CARLSBAD, CALIFORNIA 92008
W.O. 6734-D/E-SC JULY 19, 2021
Geotechnical C Geologic C Coastal C Environmental
5741 Palmer Way C Carlsbad, California 92010 C (760) 438-3155 C FAX (760) 931-0915 C www.geosoilsinc.com
July 19, 2021
W.O. 6734-D/E-SC
Mr. Robert Detrich
1230 Hoover Street
Carlsbad, California 92008
Subject: Final Soils Report of Sewer Trench Backfill, Trench Resurfacing, and Repairs,
Hoover Minor Subdivision, Assessor’s Parcel Number (APN) 206-150-12-00
and Adams Avenue, Carlsbad, San Diego County, California 92008, City of
Carlsbad Project No.: MS 14-05
References: 1. “Grading Plans for: Hoover Minor Subdivision, Carlsbad, CA,” Sheets 2 and 3 of 6,
various scales, Drawing No.: 489-5a, City of Carlsbad Project No.: MS 14-05, dated
October 22, 2018 (delta 2 revision), by Civil Landworks.
2. “Preliminary Geotechnical Evaluation, Proposed Hoover Street Subdivision,
APN 206-150-12, Carlsbad, San Diego County, California,” W.O. 6734-A-SC, dated
June 30, 2014, by GeoSoils, Inc.
Dear Mr. Detrich:
In accordance with your request, and as required by the City of Carlsbad, GeoSoils, Inc.
(GSI) has prepared this final soils report summarizing our geotechnical observations and
testing during sewer trench backfill and trench resurfacing associated with the minor
subdivision at the subject parcel. This report also presents a summary of the geotechnical
observations and testing this firm provided during the repair of the portion of
Adams Avenue in proximity to Sewer Manhole No. 1A (see Reference 1). Geotechnical
observation and testing during sewer trench backfill and trench resurfacing occurred in
August 2018. Geotechnical observation and testing during the repair of the
aforementioned portion of Adams Avenue were performed in late September 2019. Our
services were provided on a part-time, as-needed basis, as solely determined by the
contractors performing the work. During earthwork construction, line and grade was the
responsibility of others and not GSI. Unless specifically superceded herein, the
conclusions and recommendations in Reference 2 remain valid and applicable, and should
be appropriately implemented during any future development within the subject parcel.
SEWER TRENCH BACKFILL
GSI provided geotechnical observations, selective tactile probing, and field density testing
during the backfill of the trenches for the private sewer main and associated manholes, and
GeoSoils, Inc.
Mr. Robert Detrich W.O.6734-D/E-SC
Hoover Minor Subdivision, Carlsbad July 19, 2021
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laterals to Parcels 3 and 4. The trench backfill was moisture conditioned to at least
optimum moisture content, placed in relatively thin lifts, and mechanically compacted.
Field density testing indicated that the trench backfill was compacted to at least 90 percent
of the laboratory standard (per ASTM D 1557), where tested.
SEWER TRENCH RESURFACING SUBGRADE AND AGGREGATE BASE
GSI provided observations and field density testing during the contractor’s efforts to
compact the subgrade and aggregate base materials for sewer trench resurfacing in
proximity to Sewer Manhole No. 1A, located within Adams Avenue. Our field density tests
indicated that the trench subgrade and aggregate base materials were compacted to at
least 95 percent of the laboratory standard (per ASTM D 1557) and were suitable for their
intended use, where tested.
SEWER TRENCH RESURFACING ASPHALTIC CONCRETE
GSI provided observations and field density testing during the placement and compaction
of asphaltic concrete for sewer trench resurfacing in proximity to Sewer Manhole No. 1A,
located within Adams Avenue. Our field density tests indicated that the asphaltic concrete
was compacted to at least 95 percent of the maximum density, where tested.
REPAIR OF ADAMS AVENUE IN PROXIMITY TO SEWER MANHOLE NO. 1A
In order to mitigate distress to the asphaltic concrete in proximity to Sewer Manhole
No. 1A, within Adams Avenue, the existing trench backfill materials located to the
northwest and southeast of the manhole were removed to a depth of approximately 8 feet
below the adjacent finish surface. The soils exposed at the bottom of the excavation were
then compacted using mechanical equipment. Afterward, the excavated soils were placed
within the excavation, moisture conditioned to at least optimum moisture content, where
needed, and mechanically compacted. Field density testing indicated that the fill materials
were compacted to at least 90 percent of the laboratory standard (per ASTM D 1557),
where tested.
Additional compaction efforts were made within the upper approximately 12 inches of the
excavation backfill in order to prepare the subgrade for the overlying asphaltic concrete
pavement section. Where tested, our field density testing demonstrated that the upper
approximately 12 inches of the excavation backfill were compacted to at least 95 percent
of the laboratory standard (per ASTM D 1557).
Subsequently, aggregate base materials were moisture conditioned to at least optimum
moisture content, placed above the pavement subgrade, and compacted. Field density
GeoSoils, Inc.
Mr. Robert Detrich W.O.6734-D/E-SC
Hoover Minor Subdivision, Carlsbad July 19, 2021
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testing indicated that the aggregate base materials were compacted to at least 95 percent
of the laboratory standard (per ASTM D 1557), where tested.
FIELD DENSITY TESTING
1. Field density tests were performed using the nuclear densometer (ND) method, in
general accordance with ASTM test methods D 6938-10 (Procedure A) and D 2950.
The compaction test results are presented in Table 1 (see Attachment).
2. The field dry densities of the compacted fill materials and aggregate base were
evaluated as a percentage of the maximum dry density attained in the laboratory for
the representative earth material types encountered during earthwork construction.
During asphaltic concrete placement and compaction, the field wet densities,
obtained during nuclear densometer testing, were proportionately compared to the
maximum density of the asphaltic concrete, determined by the supplier’s testing
laboratory. Where field density testing indicated inadequate compaction or
moisture content (as warranted), the failure area was reworked until the
recommended compaction was achieved.
3. Field density tests were taken at periodic intervals and random locations to check
the compaction of the engineered fill placed by the contractor.
LABORATORY TESTING
Maximum Density and Optimum Moisture Content Testing
The maximum dry density and optimum moisture content for the major soil type and
aggregate base, encountered during earthwork construction, were evaluated in the
laboratory in general accordance with test method ASTM D 1557. The asphaltic concrete
supplier’s testing laboratory provided the maximum density of the asphaltic concrete. The
following table presents the maximum dry densities and optimum moisture contents of the
soils, aggregate bases, and asphaltic concrete encountered during construction:
GeoSoils, Inc.
Mr. Robert Detrich W.O.6734-D/E-SC
Hoover Minor Subdivision, Carlsbad July 19, 2021
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SOIL TYPE MAXIMUM
DENSITY (PCF)
MOISTURE
CONTENT (%)
A - Reddish Brown, Silty Sand 129.8 9.3(1)(1)
B - Class II Aggregate Base 134.0 7.0(2)(2)
B2 - Recycled Class II Aggregate Base 118.0 13.5(2)(2)
AC - Asphaltic Concrete 144.0 N/A(3)
- Maximum density and optimum moisture content evaluated by GSI.(1)
- Maximum density and optimum moisture content provided by the supplier’s testing laboratory.(2)
- Maximum density provided by the supplier’s testing laboratory.(3)
N/A - Not applicable.
CONCLUSIONS
The earthwork construction performed to date appears to be in general conformance with
the preliminary recommendations contained in Reference 2, GSI’s field recommendations,
Appendix Chapter J of the 2019 California Building Code (California Building Standards
Commission, 2019), and with the requirements of the City of Carlsbad, California, from a
geotechnical standpoint. Where field density testing was performed, the compacted fill
materials, aggregate base, and asphaltic concrete received the required compaction
efforts; and therefore, are considered suitable for their intended use from a geotechnical
perspective.
LIMITATIONS
The conclusions and recommendations presented herein are professional opinions. These
opinions have been derived in accordance with current standards of practice, and no
warranty, either express or implied, is given. Standards of practice are subject to change
with time. GSI assumes no responsibility or liability for work or testing performed by
others, or their inaction; or work performed when GSI is not requested to be onsite, to
evaluate if our recommendations have been properly implemented. Use of this report
constitutes an agreement and consent by the user to all the limitations outlined above, not
withstanding any other agreements that may be in place. In addition, this report may be
subject to review by the controlling authorities.
GeoSoils, Inc.
Mr. Robert Detrich W.O.6734-D/E-SC
Hoover Minor Subdivision, Carlsbad July 19, 2021
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If you have any questions or comments regarding this letter, please do not hesitate to
contact the undersigned.
Respectfully submitted,
GeoSoils, Inc.
John P. Franklin David W. Skelly
Engineering Geologist, CEG 1340 Civil Engineer, RCE 47857
Ryan B. Boehmer
Project Geologist
RBB/JPF/DWS/sh
Attachment: Table 1 - Field Density Test Results
Distribution: (1) Addressee (via email)
Table 1
FIELD DENSITY TEST RESULTS
TEST UTILITY DATE TEST LOCATION TRACT ELEV MOISTURE DRY REL TEST SOIL
NO.TYPE NO.OR CONTENT DENSITY COMP METHOD TYPE
DEPTH (ft)(%)(pcf)(%)
SEWER
1 S 8/1/18 Private Sewer Main Station 1+15 Hoover St.50.0 9.9 120.1 93.1 ND A
2 S 8/1/18 Private Sewer Main Station 1+10 Hoover St.52.0 10.3 121.6 94.3 ND A
3 S 8/1/18 Private Sewer Main Station 1+07 Hoover St.54.0 10.1 123.4 95.7 ND A
4 S 8/2/18 M.H.1A 1+05 Hoover St.48.0 9.7 124.3 95.7 ND A
5 S 8/2/18 M.H.1A 0+95 Hoover St.51.0 10.3 125.6 96.7 ND A
6 S 8/2/18 M.H.1A 1+05 Hoover St.53.0 9.9 123.9 95.4 ND A
7 S 8/2/18 M.H.1A 0+95 Hoover St.54.0 9.5 124.7 96.0 ND A
8 S 8/3/18 Private Sewer Main Station 1+50 Hoover St.58.0 9.9 122.1 94.7 ND A
9 S 8/3/18 Private Sewer Main Station 1+60 Hoover St.60.0 9.4 119.5 92.7 ND A
10 S 8/3/18 Private Sewer Main Station 1+80 Hoover St.62.0 9.7 120.3 93.3 ND A
11 S 8/3/18 Private Sewer Main Station 2+00 Hoover St.64.0 10.1 121.7 94.4 ND A
12 S 8/6/18 Private Sewer Main Station 2+25 Hoover St.65.0 9.9 123.1 95.5 ND A
13 S 8/6/18 Private Sewer Main Station 2+50 Hoover St.67.0 10.3 121.8 94.4 ND A
14 S 8/6/18 Private Sewer Main Station 2+75 Hoover St.71.0 10.1 122.3 94.8 ND A
15 S 8/6/18 Private Sewer Main Station 3+00 Hoover St.74.0 9.8 120.5 93.4 ND A
16 S 8/10/18 Lateral Parcel #4 Hoover St.78.0 10.5 120.3 93.3 ND A
17 S 8/10/18 Lateral Parcel #4 Hoover St.80.0 10.3 123.6 95.8 ND A
18 S 8/10/18 Lateral Parcel #4 Hoover St.82.0 10.7 119.5 92.7 ND A
19 S 8/10/18 Lateral Parcel #3 Hoover St.76.0 9.9 120.7 93.6 ND A
20 S 8/10/18 Lateral Parcel #3 Hoover St.78.0 10.2 124.1 96.2 ND A
21 S 8/10/18 Lateral Parcel #3 Hoover St.80.0 10.6 121.9 94.5 ND A
22 S 8/10/18 Main Station 3+10 Hoover St.75.0 9.7 122.4 94.9 ND A
23 S 8/10/18 Main Station 2+35 Hoover St.65.0 9.8 123.8 96.0 ND A
23'S 8/22/18 Upper Manhole Hoover St.80.0 11.4 117.9 90.8 ND A
24 S 8/22/18 Upper Manhole Hoover St.79.0 10.7 117.4 90.4 ND A
25 S 8/22/18 Lower Manhole Hoover St.56.0 11.0 128.0 98.6 ND A
26 S 8/22/18 Lower Manhole Hoover St.58.0 10.5 117.2 90.3 ND A
SEWER MANHOLE NO. 1A REPAIR
27 S 9/23/19 N.W.SIDE M.H.1A @ STA 0+94 Hoover St.49.5 9.6 118.1 91.0 ND A
28 S 9/23/19 N.W.SIDE M.H.1A @ STA 1+01 Hoover St.49.5 9.9 118.2 91.1 ND A
29 S 9/23/19 WEST SIDE OF MANHOLE Hoover St.51.0 10.1 118.1 90.9 ND A
30 S 9/23/19 WEST SIDE OF MANHOLE Hoover St.52.0 9.7 118.7 91.4 ND A
31 S 9/23/19 WEST SIDE OF MANHOLE Hoover St.53.0 9.8 119.3 91.9 ND A
32 S 9/23/19 WEST SIDE OF MANHOLE Hoover St.54.0 10.2 118.9 91.6 ND A
33 S 9/24/19 EAST SIDE MANHOLE Hoover St.48.0 11.2 122.4 94.3 ND A
34 S 9/24/19 EAST SIDE MANHOLE Hoover St.50.0 10.9 121.1 93.3 ND A
35 S 9/24/19 EAST SIDE MANHOLE Hoover St.51.5 10.5 118.5 91.3 ND A
36 S 9/24/19 EAST SIDE MANHOLE Hoover St.53.0 10.8 120.0 92.4 ND A
37 S 9/24/19 WEST SIDE MANHOLE Hoover St.55.0 9.9 124.8 96.1 ND A
38 S 9/24/19 EAST SIDE MANHOLE Hoover St.55.0 10.4 124.4 95.8 ND A
LEGEND
' = Repeated Test Number
M.H. = Manhole
ND = Nuclear Densometer Test
S = Sewer
Detrich
Hoover Minor Subdivision
File: C:\excel\tables\6700\6734d.tbl1 GeoSoils, Inc.
W.O. 6734-D-SC
July, 2021
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Table 1
FIELD DENSITY TEST RESULTS
TEST UTILITY DATE TEST LOCATION TRACT ELEV MOISTURE DRY REL TEST SOIL
NO.TYPE NO.OR CONTENT DENSITY COMP METHOD TYPE
DEPTH (ft)(%)(pcf)(%)
SUBGRADE
1 SG 8/7/2018 MH-1A Hoover St.SG 9.8 123.8 96.0 ND A
2 SG 8/7/2018 MH-1A Hoover St.SG 10.3 123.6 95.2 ND A
AGGREGATE BASE
1 AB 8/7/2018 MH-1A Hoover St.1st Lift 8.3 128.7 96.0 ND B
2 AB 8/7/2018 MH-1A Hoover St.1st Lift 8.7 129.3 96.4 ND B
3 AB 8/7/2018 MH-1A Hoover St.2nd Lift 8.1 127.9 95.4 ND B
4 AB 8/7/2018 MH-1A Hoover St.2nd Lift 7.9 128.2 95.6 ND B
ASPHALTIC CONCRETE
1 AC 8/7/2018 MH-1A Hoover St.FG n/a 137.3 95.3 ND AC
2 AC 8/7/2018 MH-1A Hoover St.FG n/a 137.7 95.6 ND AC
SEWER MANHOLE NO. 1A REPAIR
5*AB 9/25/2019 WEST SIDE MANHOLE Hoover St.BG 14.6 107.5 91.1 ND B2
5A AB 9/25/2019 WEST SIDE MANHOLE Hoover St.BG 15.2 112.5 95.3 ND B2
6*AB 9/25/2019 EAST SIDE MANHOLE Hoover St.BG 13.8 108.0 91.5 ND B2
6A AB 9/25/2019 EAST SIDE MANHOLE Hoover St.BG 14.3 113.1 95.8 ND B2
LEGEND
* = Failing Test
A = Retest
AB = Aggregate Base
AC = Asphaltic Concrete
BG = Base Grade
FG = Finish Grade
MH = Manhole
ND = Nuclear Densometer Test
SG = Subgrade
Detrich
Hoover Minor Subdivision
File: C:\excel\tables\6700\6734e.tbl1 GeoSoils, Inc.
W.O. 6734-E-SC
July, 2021
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