HomeMy WebLinkAboutCT 02-19; BRESSI RANCH PA 11; AS-GRADED GEOTECHNICAL COMPLETION LETTER; 2013-04-29Leighton and Associates, Inc.
A LEIGHTON GROUP COMPANY
April 29, 2013
Project No. 042458-003
To: Manolia Partners, LLC
2734 Loker Ave. West, Suite E
Carlsbad, CA 92010
. Attention:. Mr. Paul Colucci
Subject: As-Graded Geotchnical Completion Letter for Lot 11, Magnolia Estates,
Bressi Ranch, PA-1 1, Carlsbad, California
References: Leighton, and Associates, 2013, Geotechnical Update Letter and
Addendum Recommendations, Lots 6 and 11, Magnolia Estates, Bressi
Ranch, PA-1 1, California, Project No. 042458-001, dated March 8, 2013
Leighton and Associates, 2004, As-Graded Report of Rough and Fine
Grading, Lots 1 through 25, Planning Area PA-1 1, Bressi Ranch, Carlsbad
Tract No. 00-06, Carlsbad, California, Project No. 971009-014, dated
October 8, 2004
In, accordance with your request and authorization, Leighton and Associates, Inc.
(Leighton) has performed geotechnical observations and testing services during the fine
grading (i.e., restoration or re-processing the residential building pad) of Lot 11 at
Magnolia Estates, Bressi Ranch (PA-1 1), in Carlsbad, California. This letter summarizes
our geotechnical observations, field and laboratory test results, and the geotechnical
conditions encountered during the grading activities.
3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425
858.292.8030 • Fax 858.292.0771
042458-003
The fine grading operations were performed by C&C Equipment Rental, between April
22 and 26, 2013. During the grading, geotechnical observation and testing was
performed by a representative of Leighton. Based on our observations and testing
services, it is our professional opinion that the subject pad grading was performed in
general accordance with the recommendations of the project geotechnical report and
update letter (Leighton, 2004 and 2013) and recommendations made during the course
of grading. The geotechnical conditions encountered during grading were generally as
anticipated.
In summary, the fine grading for the building pad consisted of clearing and grubbing of
weeds, and re-processing the upper 2-feet of on-site soils (i.e., approximately 5 feet
outside of the staked building limits). Approximately 18 inches of the surface soil was
first removed then the exposed bottom was scarified a minimum depth of 6 to 10 inches,
moisture conditioned to above the optimum moisture content, and compacted to at least
90 percent relative compaction based on ASTM Test Method D1557. The subsequent
fill was then placed and compacted in 6 to 8 inches lifts. All fill soils were compacted to
a minimum 90 percent relative compaction (based on ASTM Test Method D1557) with
moisture contents approximately 3 percent above the optimum moisture content. Note
that the soil on Lot 11 was previously tested for expansion potential and determined to be
a medium (Leighton, 2004). In addition, soluble sulfate content tests of representative
finish grade soils on building pad were previously performed in accordance with ASTM
Test Method D4829 and standard geochemical methods, respectively. The laboratory test
results indicate the building pad finish grade soils possess moderate soluble sulfate
content (Leighton, 2004).
It is our professional opinion that the building pad is suitable for the intended use
provided the recommendations included in the project geotechnical report and update
letter (Leighton, 2004 and 2013) are incorporated into the design and construction of the
structures and associated improvements.
Please note that the presence of our field representative at the site was intended to
provide the owner with professional advice, opinions, and recommendations based on
observations of the contractor's work. Although the observations did not reveal obviOus
deficiencies or deviations from project specifications, we do not guarantee the
contractor's work, nor do our services relieve the contractor or his subcontractor's work,
nor do our services relieve the contractor or his subcontractors of their responsibility if
defects are subsequently discovered in their work. Our responsibilities did not include any
supervision or direction of the actual work procedures of the contractor, his personnel, or
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042458-003
subcontractors. The conclusions in this report are based on test results and observations
of the grading and earthwork procedures used and represent our engineering opinion as
to the compliance of the results with the project specifications.
If you have any questions regarding our letter, please do not hesitate to contact this
office. We appreciate this opportunity to be of service.
Respectfully submitted,
LEIGHTON AND ASSOCIATES, IN
No. 1349
CERTIFIED
,
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ENGINEtRIJ
Michael R. Sthrt, CEG 1349
Vice President / Principal Geologist
William D Olson, RCE 45283
Associate Engineer
Distribution: (3) Addressee