HomeMy WebLinkAboutCT 06-24; BRESSI RANCH VILLAGE CENTER; AS-GRADED GEOTECHNICAL COMPLETION LETTER; 2010-04-19CtO(p -'+
Leighton and Associates, Inc.
A LEIGHTON GROUP COMPANY
April 19, 2010
Project No. 971009-063
To: LNR Property Corporation
4350 Von Karman Avenue, Suite 200
Newport Beach, California 92660
Attention: Mr. Brian Payne
Subject: As-Graded Geotechnical Completion Letter. for Building Pad Major B, Bressi
Ranch Village Center, Carlsbad, California
References: Leighton, and Associates, 2007, Geotechnical Preliminary Investigation, Bressi
Ranch Village Center, A Portion of Planning Area PA-IS, Carlsbad, California,
Project No. 971009-047, dated January 25, 2007
Leighton, and Associates, 2008b, Geotechnical As-Graded Completion Report of
Rough and Fine Grading, Building Pads for Major "A" through "C", Pad "A", and
Shops "A", "B", and "D" through "G", Bressi Ranch Village Center, Carlsbad,
California, Project No 97 1009-050, dated March 24, 2008
2009a, As-Graded Report of Post Grading, Bressi Ranch Village
Center, Carlsbad, California, PrOjectNo. 971009-051, dated June 11, 2009
2009b, Geotechnical Update Letter for Major B, Bressi Ranch Village
Center, Carlsbad, California, Project No. 971009-062,dàted December 21, 2009
In accordance with your request and authorization, Leighton and Associates; Inc. (Leighton) has
performed geotechnical observation and testing services during the fine grading of the subject
building pad for the proposed for Building Pad. Major B at Bressi Ranch Village, 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
971009-063
The fine grading operations were performed by .BLT Grading and Backhoe between, April 14 and
16, 2010. 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, 2007 and
2009b) and recommendations made during the course of grading. The geotechnical conditions
encountered during grading were generally as anticipated. An as-graded report of the fine grading
for the project, documenting the work performed, is being prepared and will be issued under
separate cover.
In summary, the fine grading for subject building pad consisted of clearing and grubbing of
weeds, an approximately 1-foot removal of isolated areas based on the observed field conditions
and scarification of the surface soils. The bottom of the removal and the remaining surface soil
was scarified a minimum depth of 12 inches, moisture conditioned to above the optimum
moisture content, and compacted to at least .90 percent relative compaction based on ASTM Test
Method D1557. Fill soils on the order of 6 to 12 inches were then placed and compacted up to
the proposed finish grade elevation. All fill soils were compacted to a minimum 90 percent
relative compaction (based on'ASTM Test Method D1557) with a moisture content of between 1
to 3 percent above the optimum moisture content. Note that the soil on proposed Major B building
pad were previously tested for expansion potential and determined to be a Very Low to Low with
an Expansion Indexes of 12 and 43 (Leighton, 2008). 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 a moderate soluble sulfate content (i.e.,
identified as "Si" per ACI 318-08) (Leighton, 2008).
It is our professional opinion that the building's pad is suitable for the intended use provided the
recommendations included in the project geotechnical report and update letter (Leighton, 2007
and 2009b) 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 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.
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Leighton
971009-063
If you have any questions regarding our letter, please do not hesitate to contact this bffie. We
'appréciatè this opportunity to be of service..
Respectfully submitted,
LEIGHTON AND ASSOCIATES ANC.
GEOW (
Mike D. Jensen, CEG 2457
Project Geologist
William]) Olson, RCE 45283
Associate Engineer
Distribution: (3) Addressee