HomeMy WebLinkAboutCT 00-06; BRESSI RANCH; VERDURA RETAINING WALL COMPLETION LETTER; 2003-12-30Leighton and Associates, Inc.
A LEIGHTON GROUP COMPANY
December 30, 2003
Project No. 971009-009
To: Lennar Communities
5780 Fleet Street, Suite 320
Carlsbad, California 92008-4700
Attention: Ms. Kristine Zortman
Subject: Verdura Retaining Wall Completion Letter, Poinsettia Lane Station No. 84+25 to
85+44, Bressi Ranch, Carlsbad, California
In accordance with the request of representatives of Lennar Communities, we have been providing
geotechnical observation and testing services during the grading and construction of the proposed
Poinsettia Lane extension on the Bressi Ranch property located in Carlsbad, California. The
following is a summary of our geotechnical observations and testing services performed during the
construction of the Verdura retaining wall along the south side of Poinsettia Lane between
approximate Station No. 84+25 and 85+44. The purpose of our geotechnical observation and
testing services was to document that the construction operations for the subject retaining wall
were performed in accordance with the project geotechnical report, project plans, and the City of
Carlsbad requirements. The following items were noted:
Prior to the construction of the retaining wall, the footing excavation was observed by a
Leighton representative and found to be in general accordance with the geotechnical
recommendations (Appendix A).
Soil conditions were substantially in conformance with those assumed in the project
geotechnical report and retaining wall design parameters (Appendix A) and meet or exceed
the recommended values for backfill, foundation and retained soils. Laboratory testing of a
representative sample of the soil utilized as backfill for the retaining wall indicated the
backfill soils had a minimum internal friction angle of at least 28 degrees.
As recommended, a subdrain system was installed behind the retaining wall in general
compliance with Leighton and Southern California Geotechnical recommendations
(Appendix A).
3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425
858.292.8030 • Fax 858.292.0771 • www.leightongeo.com
971009-009
Field density testing was performed during the backfill operations of the retaining wall. The
field density test results indicated the backfill soils were compacted to a minimum 90 percent
relative compaction (based on American Standard of Testing and Materials [ASTM] Test
Method D1557). The field density test results and approximate locations performed will be
included in the final as-graded report that will be prepared upon the completion of the street
grading operations.
If you have any questions regarding this letter, please contact this office. We appreciate this
opportunity to be of service.
Respectfully submitted,
LEIGHTON AND ASSOCIATES, INC.
Randall K. Wagnei,C 1612
Director of Geology
Attachments: Appendix A - References
Distribution: (4) Addressee in I ( No. 161
Ir 02 I* (2) Lennar Communities ENGINEERING I
Attention: Ms. Lisa Galloway
(1) Lennar Communities OF CALW
Attention: Mr. Jim Urbina 1.11.1
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Leighton
971009-009
APPENDIX A
References
Leighton and Associates, Inc., 1997, Preliminary Geotechnical Investigation, Bressi Ranch,
Carlsbad, California, Project No. 4971009-002, July 29, 1997.
-, 2003a, Geotechnical Recommendations Concerning Revised Grading and Placement
of a Segmental Retaining Wall along the Existing 24-Inch Forced Sewer Main, Poinsettia
Lane Station No. 84+00 to 85+50, Bressi Ranch, Carlsbad, California, Project No.
971009-009, August 11, 2003.
-, 2003b, Geotechnical Review of Mechanically Stabilized Retaining Wall, South side
of Poinsettia Lane Between Station Nos. 84+25 and 85+44, Bressi Ranch, Carlsbad,
California, Project No. 971009-009, dated November 26, 2003.
Southern California Geotechnical, 2003a, Verdura 40 Wall Design, Station 84+25 to 85+44,
Poinsettia Lane at Bressi Ranch, Carlsbad, California, Project No. 03G236-1, dated
September 25, 2003.
-, 2003b, Addendum to Verdura 40 Wall Design, Station 84+25 to 85+44, Poinsettia
Lane at Bressi Ranch, Carlsbad, California, Project No. 03G236-2, dated December 15,
2003.
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Leighton