HomeMy WebLinkAboutCDP 2018-0038; ALLANSON-SELVIDGE RESIDENCE (CARIS RESIDENCE); FINAL SOILS REPORT; 2024-06-03
June 3, 2024
Carlsbad 5170, LLC CWE 2210126.04
6196 North Las Brisas Drive
Paradise Valley, Arizona 85253
Attention: Cathy Caris
Subject: Foundation Excavation Observations
Caris Residence, 5170 Carlsbad Boulevard, Carlsbad, California
Reference: Christian Wheeler Engineering, Report 2180441.02, Report of Preliminary Geotechnical
Investigation, dated September 21, 2018
Ladies and Gentlemen:
Christian Wheeler Engineering has provided observations and testing during the earthwork operations performed
between March 24, 2016 and October 4, 2021 at the subject site. The soil conditions at the site are substantially in
conformance with those assumed in the referenced Report of Preliminary Geotechnical Investigation. The footing
excavations for the proposed single-family residence extended to the proper depth and bearing strata in
conformance with the geotechnical report. Compacted soil placement within the foundation zone of the structures
and behind the walls has been observed and tested and is substantially in conformance with our recommendations.
Test results are presented in a separate report (CWE 2210126.03) by Christian Wheeler Engineering dated May 31,
2024. The foundation soils for the buildings have been tested and determined to have a “low” expansive potential
(EI between 21 and 50). The work observed and tested by our firm was, to the best of our knowledge, done in
accordance with the approved geotechnical report.
If you have any questions, please do not hesitate to call me at 619-550-1700.
Sincerely,
CHRISTIAN WHEELER ENGINEERING
Daniel B. Adler, R.C.E. # 36037
DBA:djf:mah
cc: tcathycaris24@gmail.com
im@hawkinsconstructioninc.com
CHRISTIAN WHEELER
E N G I N E E R I N G
Geotechnical & Geological Consulting ✦ Materials Inspection & Testing ✦ Building Envelope Consulting ✦ Laboratory Services
www.christianwheeler.com ✦ info@christianwheeler.com ✦ (619) 555-1700
AS-GRADED GEOTECHNICAL REPORT
CARIS RESIDENCE
5170 CARLSBAD BOULEVARD
CARLSBAD, CALIFORNIA
PREPARED FOR
CARLSBAD 5170, LLC
6196 NORTH LAS BRISAS DRIVE
PARADISE VALLEY, ARIZONA 85253
PREPARED BY
CHRISTIAN WHEELER ENGINEERING
3980 HOME AVENUE
SAN DIEGO, CALIFORNIA 92105
CHRISTIAN WHEELER
E N G I N E E R I N G
Geotechnical & Geological Consulting ✦ Materials Inspection & Testing ✦ Building Envelope Consulting ✦ Laboratory Services
www.christianwheeler.com ✦ info@christianwheeler.com ✦ (619) 555-1700
May 31, 2024
Carlsbad 5170, LLC CWE 2210126.03
6196 North Las Brisas Drive
Paradise Valley, Arizona 85253
Attention: Cathy Caris
Subject: As-Graded Geotechnical Report
Caris Residence, 5170 Carlsbad Boulevard, Carlsbad, California
Reference: Christian Wheeler Engineering, Report 2180441.02, Report of Preliminary Geotechnical
Investigation, dated September 21, 2018
Ladies and Gentlemen:
In accordance with your request and our proposal dated February 18, 2021, we have prepared this report to
summarize our services during the earthwork operations at the subject site. This report presents the as-graded
geotechnical conditions of the site, our observations, the results of our laboratory testing, and the results of relative
compaction tests performed in the fills and backfills that were placed during the grading operation at the project
site. The observation and testing services addressed by this report were coordinated by Solera General Contracting
and were provided between March 24 and October 4, 2021.
In order to assist in our understanding of the designed configuration of the project, our firm was provided with a
grading plan (Drawing No. 520-4A) for the site prepared by Pasco Laret, Suiter & Associates, bearing an approval
date from the City of Carlsbad of January 28, 2021. The plans are titled “Allison- Selvidge Residence” after the
previous owners. Plate No. 1 of this report is a reproduction of the grading plan, modified to show the
approximate locations of our field tests and the relevant limits of the earthwork operation.
INTRODUCTION AND PROJECT DESCRIPTION
The subject site is a rectangular-shaped lot located at 5170 Carlsbad Boulevard, Carlsbad, California. The lot is
bounded to the west by Carlsbad Boulevard, and is otherwise bounded by developed residential lots. Prior to the
earthwork addressed in this report, site supported a residential structure. Topographically, the majority of the site
CHRISTIAN WHEELER
E N G I N E E R I N G
Geotechnical & Geological Consulting ✦ Materials Inspection & Testing ✦ Building Envelope Consulting ✦ Laboratory Services
www.christianwheeler.com ✦ info@christianwheeler.com ✦ (619) 555-1700
CWE 2210126.03 May 31, 2024 Page 2
was flat-lying. Elevations ranged from about 55 feet along the western property line to about 58 feet at the
southeastern corner of the site.
The structure and associated improvements that were located on-site were demolished to accommodate the new
construction. A new two- and three-story residential structure that includes a subterranean level has been
constructed. The structure is of masonry and wood-frame construction with on-grade concrete floor slabs, and is
supported by conventional shallow foundations. Grading to accommodate these improvements consisted of cuts
of up to about 12 feet from existing site grade.
SCOPE OF SERVICE
The following services were provided by Christian Wheeler Engineering during the course of the earthwork
operations.
Provided periodic observation of the earthwork operations.
Observe the drilling of the shoring system soldier piles to verify compliance with the project documents.
Provided field recommendations for elements of the earthwork not specifically addressed by the referenced
geotechnical report, as needed.
Recorded the approximate elevations and limits of significant geotechnical elements.
Performed in-place density tests in the fills and backfill placed.
Determined the laboratory maximum density and optimum moisture content and expansion index of soils
encountered in the earthwork.
Prepared this report, which presents a summary of our observations and results of our relative compaction
tests.
SITE PREPARATION AND GRADING
The earthwork addressed by this report was performed by Romo’s Grading. Prior to the commencement of the
grading operations a temporary shoring wall was constructed by Western Foundations and Shoring along the
northerly property line, north of the basement. Grading proceeded with cuts for the proposed basement which
exposed competent old paralic deposits. The approximate limits of the basement excavation are shown on the
attached Plate No. 1
Removals for the at grade portion of the residence were performed as backfill operations progressed for the
basement retaining walls. This consisted of benching into the basement backcuts laterally to encompass the at
grade portions of the structure. Competent old paralic deposits were exposed in the removals which extend
approximately 4 feet below the proposed grades to an elevation of approximately 53 feet. Approximate limits of
CWE 2210126.03 May 31, 2024 Page 3
removals and the retaining wall backcuts are shown on the attached Plate No. 1. Fill materials consisting of the on-
site and imported silty or clayey sands were typically placed by an excavator in relatively thin, uniform lifts.
Moisture-conditioning was applied as needed and compactive efforts were then performed by means of manually
operated reciprocating compactors and/or a walk behind roller to attain at least 95 percent of the maximum dry
density.
During the removal operations, an infilled vertical seepage pit was encountered in the area of the proposed
stairway along the northeast side of the proposed residence. The vertical seepage pit was measured to be
approximately 4 feet in diameter and had been infilled with loose soil. We provided recommendations to the
contractor for a reinforced concrete cap be constructed over the opening however, we were never requested to
observe any elements of the reinforced concrete cap construction. The approximate location of the seepage pit is
shown on the attached Plate No. 1
RETAINING WALL BACKFILL OBSERATION
Basement retaining walls were generally backfilled using native sandy soils. The backfills were placed in thin
horizontal lifts, which were watered to near optimum conditions and compacted in place by means of the
reciprocating compactors to at least 95 percent of maximum dry density. The void between the north side of the
basement retaining wall and the temporary shoring wall was backfilled with crushed rock encapsulated in filter
fabric. The location of the rock backfills and top of rock backfill elevations are shown on Plate No. 1.
LABORATORY AND FIELD TESTING
Maximum dry density and optimum moisture content of the soils predominantly encountered in the earthwork
were determined in our laboratory in accordance with ASTM D1557, “Test Method for Laboratory Compaction
Characteristics of Soil Using Modified Effort.” Tests were conducted in accordance with the methodology
prescribed for the grain-size distribution of the soils tested. Tests results are presented in Appendix A on Table I.
A sample of the imported soil used to cap the building pad for the single-family residence was tested for its
expansion potential in accordance with ASTM D4829, “Standard Test Method for Expansion Index of Soils.”
The result of this test is presented in Appendix A on Table II.
Field tests to measure the in-place density and moisture content of the fills and backfills were conducted in
accordance with ASTM D6938, “Standard Test Methods for Density of Soil and Soil-Aggregate in Place by
Nuclear Methods.” Field test locations were selected by our technician in areas discerned to exhibit compaction
that was generally representative of that attained in the soil. Tests results are presented in Appendix A on Table
III and IV.
CWE 2210126.03 May 31, 2024 Page 4
CONCLUSIONS
It is the opinion of Christian Wheeler Engineering that the earthwork addressed by this report has been performed
in accordance with the recommendations presented in the referenced geotechnical report, the grading requirements
of the City of Carlsbad and the California Building Code. This opinion is based upon our observations of the
earthwork operations, the results of the density tests taken in the field, and the maximum density tests performed
in our laboratory. It is our further opinion that the site is suitable for the proposed construction.
AS-BUILT GEOLOGY
The geologic units encountered during the earthwork operations were generally consistent with those anticipated
in our referenced report of geotechnical investigation. No unforeseen, adverse geologic conditions or features
were noted by our field personnel during the earthwork operation addressed herein. The earthwork operations
addressed by this report have, in our opinion, satisfactorily mitigated the potentially adverse conditions described
in the referenced report.
LIMITATIONS
The descriptions, conclusions and opinions presented in this report pertain only to the work performed on the
subject site during the period from March 24 to October 4, 2021. As limited by the scope of the services that we
agreed to perform, the conclusions and opinions presented herein are based upon our observations of the work
and the results of our laboratory and field tests. Our services were performed in accordance with the currently
accepted standard of practice in the region in which the earthwork was performed, and in such a manner as to
provide a reasonable measure of the compliance of the described work with applicable codes and specifications.
With the submittal of this report, no warranty, express or implied, is given or intended with respect to the services
performed by our firm, and our performance of those services should not be construed to relieve the grading
contractor of his responsibility to perform his work to the standards required by the applicable building codes and
project specifications.
Christian Wheeler Engineering sincerely appreciates the opportunity to provide professional services on this
project. If you should have any questions after reviewing this report, please do not hesitate to contact our firm.
Respectfully submitted,
CHRISTIAN WHEELER ENGINEERING
___________________________________ ___________________________________
Daniel B. Adler, RCE #36037 Daniel J. Flowers, CEG #2686
DBA:djf:mah
ec: tcathycaris24@gmail.com
im@hawkinsconstructioninc.com
RW
7
RW
4 RW
10
RW
14
RW
6
RW
18
RW
8
RW
13
RW
1
RW
2
RW
16
RW
11
RW
5
RW
9
RW
12
RW
17
2
1
3
RW
3
4
RW
15
Qop
Qaf
Qop
Qaf
Qop
Qaf
Qop
53.0'
47.5'
53.0'
53.0'
Top of Rock Elevation
=51.0'Top of Rock Elevation
=53.8'
CARIS RESIDENCE5170 CARLSBAD BOULEVARD, CARLSBAD, CALIFORNIA
DATE: AUGUST 2019
BY: MAH PLATE NO.: 1
MAY 2024
AS-GRADED GEOTECHNICAL MAP
REPORT NO.: 2210126.03
47.5'
RELATIVE COMPACTION TEST
OLD PARALIC DEPOSITS
APPROXIMATE LIMITS OF
BASEMENT
CWE LEGEND
APPROXIMATE LIMITS OF
RETAINING WALL BACKCUTS
ELEVATIONS AT EXCAVATION
BOTTOM
#
ARTIFICIAL FILLS OBSERVED
BY CWE OVER OLD PARALIC
DEPOSITS
APPROXIMATE LIMITS OF
REMOVALS
APPROXIMATE LIMITS OF
ROCK BACKFILLS
Qop
Qaf
Qop
APPROXIMATE LOCATION OF
VERTICAL SEEPAGE PIT
Appendix A
Test Results
CWE 2210126.03 May 31, 2024 Appendix A, Page A-1
TABLE I: SUMMARY OF OPTIMUM MOISTURE & MAXIMUM DENSITY TEST RESULTS (ASTM D1557)
Soil
Type Description Optimum Moisture
(%)
Maximum Dry
Density (pcf)
1 Light Brown, Silty Sand 9.2 122.5
2 Light Brown, Silty Sand 9.5 124.0
3 Light Gray Clayey Sand (Import)11.9 118.7
TABLE II: FINISH GRADE EXPANSION INDEX (ASTM 4829)
Soil Type Expansion Index Classification
3 37 Low
TABLE III: SUMMARY OF FIELD IN-PLACE DENSITY TEST RESULTS (ASTM D6938) - RETAINING WALL
Test
No.Date Location Elev.
(feet)
Soil
Type
Field
Moisture
(%)
Field
Dry
Density
(pcf)
Max.
Density
(pcf)
Rel.
Comp.
(%)
RW1 7/16/2021 East Basement Wall 48.0 1 11.6 111.7 122.5 91.2
RW2 7/16/2021 Retest RW1 48.0 1 9.4 117.2 122.5 95.7
RW3 7/16/2021 South Basement Wall 48.0 1 9.3 118.3 122.5 96.6
RW4 7/16/2021 South Basement Wall 49.0 1 9.6 116.9 122.5 95.4
RW5 7/19/2021 East Basement Wall 50.0 2 9.5 120.2 124.0 96.9
RW6 7/19/2021 South Basement Wall 50.0 2 9.7 119.3 124.0 96.2
RW7 7/21/2021 South Basement Wall 50.0 2 9.8 118.2 124.0 95.3
RW8 7/21/2021 South Basement Wall 51.0 2 9.5 119.4 124.0 96.3
RW9 7/21/2021 East Basement Wall 52.0 2 9.6 118.5 124.0 95.6
RW10 7/26/2021 South Basement Wall 53.0 2 7.8 121.7 124.0 98.1
RW11 7/26/2021 East Basement Wall 53.5 2 7.2 120.3 124.0 97.0
RW12 7/28/2021 East Basement Wall 55.0 2 7.0 120.3 124.0 97.0
RW13 7/28/2021 South Basement Wall 55.0 2 11.4 118.4 124.0 95.5
RW14 7/28/2021 South Basement Wall 55.0 2 7.0 119.7 124.0 96.5
RW15 7/28/2021 West Basement Wall 55.0 2 8.7 121.2 124.0 97.7
RW16 8/17/2021 East Basement Wall 56.0 3 12.1 114.3 118.7 96.3
RW17 8/17/2021 East Basement Wall 56.0 3 12.5 113.7 118.7 95.8
RW18 8/17/2021 South Basement Wall 56.0 3 11.9 115.2 118.7 97.1
TABLE IV: SUMMARY OF FIELD IN-PLACE DENSITY TEST RESULTS (ASTM D6938) - MASS GRADING
Test
No.Date Location Elev.
(feet)
Soil
Type
Field
Moisture
(%)
Field
Dry
Density
(pcf)
Max.
Density
(pcf)
Rel.
Comp.
(%)
1 8/17/2021 Flatwork, East of Residence 57.0 3 11.2 113.8 118.7 95.9
2 8/17/2021 Flatwork, Southeast of Residence 57.0 3 9.8 114.1 118.7 96.1
3 8/17/2021 Flatwork, Southwest of Residence 57.0 3 10.1 112.9 118.7 95.1
4 8/17/2021 Flatwork, West of Residence 57.0 3 10.9 115.8 118.7 97.6