HomeMy WebLinkAboutMS 05-09; ACACIA ESTATES; FINAL SOILS REPORT; 2019-07-16SUMMARY OF GEOTECHNICAL OBSERVATION AND
TESTING DURING GRADING WITHIN THE CONDOMINIUM BUILDING
FOOTPRINT AND UNDERGROUND UTILITY TRENCH BACKFILL
AND CURB AND GUTTER, SIDEWALK, AND DRIVEWAY APPROACH
RAMP CONSTRUCTION WITHIN THE ACACIA AVENUE RIGHT-OF-WAY
ACACIA CONDOMINIUMS, 163 ACACIA AVENUE
CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA 92008
FOR
ACACIA AVE. CAH, LLC
C/O THE EDWARD GROUP
P.O. BOX 408
RANCHO SANTA FE, CALIFORNIA 92067
W.O. 7368-B/D/E-SC JULY 16, 2019
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 16, 2019
W.O. 7368-B/D/E-SC
Acacia Ave. CAH, LLC
c/o The Edward Group
P.O. Box 408
Rancho Santa Fe, California 92067
Attention:Mr. Todd Parnell
Subject:Summary of Geotechnical Observation and Testing During Grading within
the Condominium Building Footprint and Underground Utility Trench Backfill,
and Curb and Gutter, Sidewalk, and Driveway Approach Ramp Construction
within the Acacia Avenue Right-of-Way, Acacia Condominiums, 163 Acacia
Avenue, Carlsbad, San Diego County, California 92008
Dear Mr. Parnell:
In accordance with your request and authorization, GeoSoils, Inc. (GSI) is providing this
summary of geotechnical observations and testing during grading within the condominium
building footprint at the subject site and during underground utility trench backfill, and curb
and gutter, sidewalk, and driveway approach ramp construction within the Acacia Avenue
right-of-way (ROW). Unless specifically superceded herein, the conclusions and
recommendations contained in the project geotechnical reports, prepared by this firm (see
Appendix A), remain pertinent and applicable, and should be appropriately implemented
over the life of the development, and for any future development projects within the subject
property.
GRADING WITHIN THE CONDOMINIUM BUILDING FOOTPRINT
Grading under the purview of this report generally occurred within the building footprint of
the condominium structure. Grading commenced on or about January 18, 2018 and was
generally completed on January 25, 2018. During grading, line and grade was the
responsibility of others, and not GSI.
Summary of Grading
Grading generally included planned cuts of approximately 6¼ to 10¼ feet below the
existing grades. During planned excavation for the basement floor level, potentially
compressible colluvium (topsoil) and weathered old paralic deposits were removed.
GeoSoils, Inc.
Acacia Ave. CAH, LLC W.O. 7368-B/C/E-SC
163 Acacia Avenue, Carlsbad July 16, 2019
File:e:\wp12\7300\7368bde.sog Page 2
Following planned excavation, unweathered old paralic deposits, exposed at the basement
floor level pad grade elevation, were overexcavated to at least 2 feet below the lowest
foundation element. According to the grading contractor, the overexcavation was
completed to 2½ feet laterally outside the backs of the basement retaining walls in order
to capture the entire foundation for the basement floor level.
Following overexcavation, the bottom of the overexcavation was observed by GSI field
personnel, moisture conditioned, and recompacted. The excavated onsite earth materials
were then generally cleaned of organic matter and deleterious debris, placed in relatively
thin lifts, moisture conditioned and mixed to at least optimum moisture content, and then
compacted to at least 95 percent of the laboratory standard (ASTM D 1557), where tested.
An existing vertical seepage pit or cistern was exposed during planned excavation near the
southeasterly corner of the basement floor level footprint. Following the issuance of
GSI (2018a), the foundation subcontractor removed this structure and the undocumented
fill contained therein until suitable old paralic deposits were encountered. The resultant
excavation was then backfilled with the excavated soils until the approximate basement
subgrade elevation was attained. The backfill soils were moisture conditioned and mixed
to achieve at least optimum moisture content and then compacted to at least 95 percent
of the laboratory standard (ASTM D 1557), where tested.
The as-graded geotechnical conditions within the limits of grading under the purview of this
report are shown on Plate 1 (Field Density Test Location Map). Plate 1 also shows the
bottom of the overexcavation for the basement floor level and the remedial excavation
associated with the removal of the vertical seepage pit or cistern. Compacted fill
thicknesses within the limits of grading under the purview of this report vary between
approximately 4 and 12½ feet.
BASEMENT SUBGRADE PREPARATION
Following building foundation construction, the basement subgrade was prepared by fine
grading. This included the removal any loose spoil and stockpiled earth materials, and
filling low areas until the basement subgrade or finish grade was achieved. Fill materials
were moisture conditioned and mixed to achieve at least optimum moisture content, and
compacted to at least 95 percent of the laboratory standard (ASTM D 1557), where tested.
SEWER LATERAL BACKFILL TESTING
GSI performed observations and field density testing during the backfill of the sewer lateral
trenches within the Acacia Avenue ROW. Soil backfill materials were moisture conditioned
and mixed to at least optimum moisture content, placed in relatively thin lifts, and
mechanically compacted. Field density tests indicated that the trench backfill materials
GeoSoils, Inc.
Acacia Ave. CAH, LLC W.O. 7368-B/C/E-SC
163 Acacia Avenue, Carlsbad July 16, 2019
File:e:\wp12\7300\7368bde.sog Page 3
were compacted to at least 90 percent of the laboratory standard (ASTM D 1557), where
tested. Where tested, the upper 12 inches of the sewer lateral backfill materials
(i.e., subgrade) were found to have been compacted to at least 95 percent of the
laboratory standard (ASTM D 1557). Where gravel was used to backfill the sewer lateral
trenches, the contractor placed a non-woven filter fabric between the top of the gravel
backfill and the overlying soil backfill.
SEWER AND WATER LATERAL AGGREGATE BASE TESTING (GSI PHASE E)
Recycled Class II aggregate base materials were placed near the top of the sewer and
water lateral trenches as part of the trench resurfacing. Field density tests indicated that
the aggregate base materials were moisture conditioned to at least optimum moisture
content and compacted to at least 95 percent of the laboratory standard (ASTM D 1557),
where tested.
CURB AND GUTTER SUBGRADE AND AGGREGATE BASE TESTING
(GSI PHASE E)
GSI performed field density testing on subgrade materials for the curb and gutter along the
southerly side of Acacia Avenue, in front of the subject address. Where tested, the curb
and gutter subgrade was moisture conditioned to at least optimum moisture content and
compacted to at least 95 percent of the laboratory standard (ASTM D 1557).
DRIVEWAY APPROACH RAMP AND SIDEWALK SUBGRADE AND AGGREGATE
BASE OBSERVATION AND TESTING (GSI PHASE E)
GSI performed field density testing on the driveway approach ramp and sidewalk
subgrades located within the City of Carlsbad ROW. Where tested, the driveway approach
ramp subgrade was moisture conditioned to at least optimum moisture content and
compacted to at least 95 percent of the laboratory standard (ASTM D 1557). Field density
testing also indicated that the sidewalk subgrade was moisture conditioned to at least
optimum moisture content and compacted to at least 90 percent of the laboratory standard
(ASTM D 1557), where testing was performed.
FIELD TESTING
1.Field density tests were performed using the nuclear (densometer) method
(ASTM D 6938-10 [Procedure A]) and the sand-cone method ASTM D 1556.
The test results are presented on the attached Table 1. The approximate locations
of field density tests performed during grading within the building footprint are
shown on Plate 1.
GeoSoils, Inc.
Acacia Ave. CAH, LLC W.O. 7368-B/C/E-SC
163 Acacia Avenue, Carlsbad July 16, 2019
File:e:\wp12\7300\7368bde.sog Page 4
2.Field density tests were taken at periodic intervals and selected locations to check
the compactive efforts provided by the contractor. Where test results indicated less
than optimum moisture content, or less that the necessary relative compaction, the
contractor was notified and the area was reworked until retesting indicated at least
optimum moisture and the specified relative compaction was achieved.
3.Visual classification, supplemented by laboratory testing, was the basis for
evaluating which maximum density value to use for a given density test.
4.Field testing and observations were performed on an as-needed, part-time basis,
as solely determined by the Client. GSI relied on the Client for notification of site
earthwork.
LABORATORY TESTING
Maximum Density Testing
The laboratory maximum dry density and optimum moisture content for each of the major
soil types, encountered during earthwork construction was evaluated in general
accordance with test method ASTM D 1557. The following table presents the results.
SOIL TYPE
MAXIMUM DENSITY
(PCF)
MOISTURE CONTENT
(PERCENT)
A - Brown Sand with trace Silt and Gravel 120.0 10.8
B - Recycled Class II Aggregate Base 118.5 (±2.0)*12.0*
C - Class II Aggregate Base 145.5 4.9
* - Provided by supplier’s test laboratory.
Expansion Index
A representative sample of soils exposed near finish pad grade of the basement floor level
was tested for expansion potential. Expansion Index (E.I.) testing and expansion potential
classification was performed in general accordance with ASTM Standard D 4829, the
results of the testing are provided in the following table.
EXPANSION INDEX EXPANSION POTENTIAL
<5 Very Low
GeoSoils, Inc.
Acacia Ave. CAH, LLC W.O. 7368-B/C/E-SC
163 Acacia Avenue, Carlsbad July 16, 2019
File:e:\wp12\7300\7368bde.sog Page 5
Saturated Resistivity, pH, and Soluble Sulfates and Chlorides
Tests were performed to evaluate the pH, saturated resistivity, and the soluble sulfate and
chloride concentrations of soils exposed near finish pad grade of the basement floor level.
Testing was performed in general accordance with California Test Methods CT-417, CT-
422, and CT-532 (643). Ranges of the test results are presented in the table below. The
test results are included in Appendix B.
pH
SATURATED
RESISTIVITY
(ohm-cm)
SOLUBLE
SULFATES
(% by weight)
SOLUBLE
CHLORIDES
(ppm)
7.4 6,700 0.0156 84
Corrosion Summary
Laboratory testing indicates that the tested sample of the finish grade soils at the basement
floor level is mildly alkaline with respect to soil acidity/alkalinity; is moderately corrosive to
exposed, buried metals when saturated; presents negligible sulfate exposure to concrete
(i.e., Exposure Class S0 per Table 19.3.1.1 of American Concrete Institute [ACI] 318-14);
and have slightly elevated concentrations of soluble chlorides. It should be noted that
GSI does not consult in the field of corrosion engineering. Therefore, additional comments
and recommendations may be obtained from a qualified corrosion engineer based on the
level of corrosion protection required for the project, as determined by the project architect,
civil engineering, and/or structural engineer.
CONCLUSIONS
Where GSI was requested to perform observations and field density testing, earthwork
construction was found to be in general conformance with the recommendations in the
project geotechnical reports (see Appendix A) and City of Carlsbad standards.
RECOMMENDATIONS
Adequate surface drainage should be maintained throughout the life of the project.
GeoSoils, Inc.
Acacia Ave. CAH, LLC W.O. 7368-B/C/E-SC
163 Acacia Avenue, Carlsbad July 16, 2019
File:e:\wp12\7300\7368bde.sog Page 6
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,
notwithstanding any other agreements that may be in place. In addition, this report may
be subject to review by the controlling authorities.
GeoSoils, Inc.
Acacia Ave. CAH, LLC W.O. 7368-B/C/E-SC
163 Acacia Avenue, Carlsbad July 16, 2019
File:e:\wp12\7300\7368bde.sog Page 7
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
RB/JPF/DWS/jh
Attachments:Table 1 - Field Density Test Results
Appendix A - References
Appendix B - Laboratory Test Results
Plate 1 - Field Density Test Location Map
Distribution:(3) Addressee (via US mail and 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)(%)
GRADING
1 1/23/18 SE Area MS 05-09 42.5 11.8 115.8 96.5 ND A
2 1/23/18 SE Area MS 05-09 42.5 11.0 114.7 95.6 ND A
3 1/23/18 SW Area MS 05-09 42.5 11.0 114.7 95.6 ND A
4 1/23/18 SW Area MS 05-09 43.0 11.0 114.7 95.6 ND A
5 1/24/18 SE Area MS 05-09 45.0 12.0 114.0 95.0 SC A
6 1/24/18 SE Area MS 05-09 45.0 11.5 114.6 95.5 ND A
7 1/24/18 SW Area MS 05-09 45.0 10.6 115.0 95.8 ND A
8 1/24/18 NW Area MS 05-09 42.5 10.9 114.3 95.3 ND A
9*1/24/18 NW Area MS 05-09 42.5 11.4 111.1 92.6 ND A
9A 1/24/18 NW Area MS 05-09 42.5 11.0 116.2 96.8 SC A
10 1/25/18 SW Area MS 05-09 45.0 10.9 114.5 95.4 ND A
11 1/25/18 N. Central Area MS 05-09 43.0 11.1 115.2 96.0 SC A
12 1/25/18 NE Area MS 05-09 42.5 10.8 114.7 95.6 ND A
13 1/25/18 NE Area MS 05-09 42.5 10.9 114.1 95.1 ND A
14 1/25/18 NE Area MS 05-09 45.0 11.4 114.9 95.8 ND A
15 1/25/18 NE Area MS 05-09 45.0 12.0 115.5 96.3 ND A
16 1/25/18 NE Area MS 05-09 43.0 11.1 114.9 95.8 ND A
17 2/8/18 Vert. Seepage Pit MS 05-09 34.0 14.2 115.0 95.8 ND A
18 2/8/18 Vert. Seepage Pit MS 05-09 36.0 13.5 116.2 96.8 SC A
19 2/8/18 Vert. Seepage Pit MS 05-09 38.0 12.8 114.9 95.8 ND A
20 2/8/18 Vert. Seepage Pit MS 05-09 40.0 11.3 114.1 95.1 ND A
21*2/8/18 Vert. Seepage Pit MS 05-09 41.0 11.1 111.1 92.6 SC A
21A 2/8/18 Vert. Seepage Pit MS 05-09 41.0 11.0 114.2 95.2 ND A
22 5/25/18 South Side of Unit 4 MS 05-09 FG 10.9 114.1 95.1 ND A
23 5/25/18 South Side of Unit 4 MS 05-09 FG 11.1 115.2 96.0 ND A
24 5/25/18 South Side of Unit 3 MS 05-09 FG 11.2 114.5 95.4 ND A
25 5/25/18 North Side of Unit 1 MS 05-09 FG 10.9 114.7 95.5 ND A
26 5/25/18 North Side of Unit 2 MS 05-09 FG 11.3 114.9 95.7 ND A
27 6/11/18 North Side Unit 4 MS 05-09 FG 10.8 115.1 95.9 ND A
28 6/11/18 North Side Unit 3 MS 05-09 FG 11.1 114.2 95.1 ND A
29 6/11/18 North Side Unit 2 MS 05-09 FG 10.9 114.9 95.7 ND A
30 6/11/18 South Side Unit 2 MS 05-09 FG 11.4 115.1 95.9 ND A
SEWER LATERAL TRENCH BACKFILL
1 SL 5/29/18 SewerLat, Acacia Ave 1+13 MS 05-09 FG-4 11.0 113.1 94.2 ND A
2 SL 5/29/18 SewerLat, Acacia Ave 1+10 MS 05-09 FG-3 10.9 112.9 94.0 ND A
3 SL 5/29/18 SewerLat, Acacia Ave 1+12 MS 05-09 FG-2 11.1 113.7 94.7 ND A
4 SL 5/30/18 SewerLat, Acacia Ave 1+94 MS 05-09 FG-6 11.0 112.5 93.7 ND A
5 SL 5/30/18 SewerLat, Acacia Ave 1+92 MS 05-09 FG-4 11.1 113.9 94.9 ND A
6 SL 5/30/18 SewerLat, Acacia Ave 1+93 MS 05-09 FG-2.5 11.1 115.4 96.1 ND A
7 SL 5/30/18 SewerLat, Acacia Ave 1+94 MS 05-09 FG-1 10.9 114.3 95.2 ND A
8 SL 6/1/18 SewerLat, Acacia Ave 1+13 MS 05-09 FG-3 10.9 112.7 93.9 ND A
9 SL 6/1/18 SewerLat, Acacia Ave 1+13 MS 05-09 FG-1 11.0 113.1 94.2 ND A
10 SL 6/1/18 SewerLat, Acacia Ave 1+13 MS 05-09 SG 11.0 115.7 96.4 ND A
SEWER AND WATER TRENCH RESURFACING AGGREGATE BASE
1 BG 6/11/18 Acacia Ave. 1+96 MS05-09 BG 12.1 113.1 95.4 ND B
2 BG 6/11/18 Acacia Ave. 1+12 MS05-09 BG 12.2 112.7 95.1 ND B
Acacia Ave CAH, LLC
163 Acacia Ave., Carlsbad
File:C:\excel\tables\7300\7368bde.sog GeoSoils, Inc.
W.O.7368-B/D/E
July, 2019
Page 1
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)(%)
3 BG 6/11/18 Acacia Ave. 1+25 MS05-09 BG 12.0 113.8 96.0 ND B
4 BG 6/11/18 Acacia Ave. 1+80 MS05-09 BG 12.2 112.9 95.2 ND B
CURB AND GUTTER SUBGRADE
1 CSG 6/4/19 163 Acacia MS05-09 SG 11.0 115.0 95.8 ND A
2 CSG 6/4/19 163 Acacia MS05-09 SG 10.8 115.8 96.5 ND A
3 CSG 6/4/19 163 Acacia MS05-09 SG 10.5 115.3 96.1 ND A
DRIVEWAY APPROACH RAMP & SIDEWALK SUBGRADE
5 SG 6/7/19 163 Acacia DW Approach MS05-09 SG 10.9 115.2 96.0 ND A
6 SG 6/7/19 163 Acacia Sidewalk MS05-09 SG 12.0 110.0 91.7 ND A7SG6/7/19 163 Acacia Sidewalk MS05-09 SG 10.8 108.7 90.6 ND A
CURB AND GUTTER, AND DRIVEWAY APPROACH RAMP AGGREGATE BASE
1 BG 6/5/19 163 Acacia MS05-09 BG 11.0 139.5 95.9 ND C
2 BG 6/5/19 163 Acacia MS05-09 BG 10.8 138.8 95.4 ND C
3 BG 6/5/19 163 Acacia MS05-09 BG 10.5 138.3 95.1 ND C
4 BG 6/10/19 163 Acacia Driveway MS05-09 BG 5.8 139.3 95.7 ND C
LEGEND
* = Failing Test ND = Nuclear Densometer Test
A = Retest SC = Sand Cone Test
BG = Base Grade SG = Subgrade
CSG = Curb and Gutter Subgrade SL = Sewer Lateral
FG = Finish Grade
Acacia Ave CAH, LLC
163 Acacia Ave., Carlsbad
File:C:\excel\tables\7300\7368bde.sog GeoSoils, Inc.
W.O.7368-B/D/E
July, 2019
Page 2
GeoSoils, Inc.
APPENDIX A
REFERENCES
GeoSoils, Inc.
APPENDIX A
REFERENCES
BHA, Inc., 2017, Grading plans for: Acacia Estates, APNs 204-231-06 & -08, sheets 1
through 5 of 8, various scales, dated December 14.
GeoSoils, Inc., 2019, Documentation of geotechnical services requested during earthwork
construction, Acacia Condominiums, 163 Acacia Avenue, Carlsbad,
San Diego County, California 92008, W.O. 7368-B/C/D/E/F-SC, dated July 12.
_____, 2018a, Interim compaction report of grading, basement floor level, Acacia
Condominiums, 163 Acacia Avenue, Carlsbad, San Diego County, California 92008,
W.O. 7368-B-SC, dated February 5.
_____, 2018b, Geotechnical review of structural plans and calculation package, Acacia
Estates, 163 Acacia Avenue, Carlsbad, San Diego County, California 92008,
W.O. 7368-B-SC, dated January 22.
_____, 2017a, Geotechnical addendum and response to City of Carlsbad plan check no. 3
comments, Acacia Estates, 155 and 163 Acacia Avenue, Carlsbad, San Diego
County, California 92008, City of Carlsbad Project No.: MS 05-09 W.O. 7368-B-SC,
dated December 6.
_____, 2017b, Grading plan and retaining wall review, response to redline comments from
the City, 155 and 163 Acacia Avenue, Carlsbad, San Diego County, California
92008, W.O. 7368-A-SC, dated October 26.
_____, 2016, Geotechnical update, proposed Acacia Estates 4-unit development at 155
and 163 Acacia Avenue, Carlsbad, San Diego County, California 92008
APNs 204-231-06 and -08, W.O. 7142-A-SC, dated August 25.
_____, 2005, Preliminary geotechnical evaluation, 163 and 165 Acacia Avenue, Carlsbad,
San Diego County, California, W.O. 4734-A-SC, dated April 6.
GeoSoils, Inc.
APPENDIX B
LABORATORY TEST RESULTS
W.O. 7368-B-SC
PLATE 1