HomeMy WebLinkAboutPD 2020-0042; 4100 SUNNYHILL DRIVE; RESPONSE TO CITY OF CARLSBAD REVIEW GEOTECHNICAL INVESTIGATION 4100 SUNNYHILL DRIVE; 2021-01-13HETHERINGTON ENGINEERING, INC.
SOIL & FOUNDATION ENGINEERING• ENGINEERING GEOLOGY• HYDROGEOLOGY
Ron Severino
3295 Pio Pico Drive
Carlsbad, California 92008
Subject: RESPONSE TO CITY OF CARLSBAD REV lEW
Proposed Retaining Wall
4100 Sunny IIill Drive
Carlsbad, California
References: Attached
Dear Mr. Severino:
January 13, 2021
Project No. 9235.1
Log No. 21279
In accordance with your request, we me providing the following response to the reclli.ne
comments by the City of Carlsbad to the "Geo technical Investigation ... " (Reference 1 ).
The following are site grading recommendations for fill placement between proposed
retaining wall and existing retaining wall, provided that slope grades are 5: 1 (horizontal to
vertical) or less:
Prior to grading, the areas of the proposed fi ll placement should be cleared of existing
vegetation and debris. Materials generated dming clearing should be disposed of at an
approved location off-site. In the areas of proposed fill and improvements, existing
undocumented fill should be removed down to approved Paralic Deposits and replaced
with compacted fill in order to achieve design finish grades. Removals on the order of 1 to
3-feet are expected. Actual depths should be determined in the field by the Geotechnical
Consultant based on conditions exposed during grading.
Following removals, the exposed subgrade should be scarified to a depth of 6 to 8-inches,
moisture conditioned to about optimmn moistme content and compacted to at least 90-
percent relative compaction.
Fill should be compacted by mechanical means in uniform horizontal lifts of 6 to 8-inches
in thickness. All fill should be brought to near optimW11 moisture content and compacted
to a minimum relative compaction of 90-pecent based upon ASTM: D 1557. The on-site
materials are suitable for use as compacted as compacted fill provided all vegetation and
debris me removed. Rock fragments over 6-inches in dimension and other perishable or
unsuitable materials should be excluded from the fi ll. All grading and compaction should
be observed and tested as necessary by the Geotechnical Consultant.
5365 Avenida Encinas, Suite A• Carlsbad, CA 92008-4369 • (760) 931 -1917 • Fax (760) 931-0545
333 Third Street, Suite 2 • Laguna Beach, CA 92651-2306 • (949) 715-5440 • Fax (760) 931-0545
www.hetheringtonengineering.com
RESPONSE TO CITY OF SAN DIEGO GEOLOGY REVIEW
Project No. 9235.1
Log No. 2 1279
January 13, 202 1
Page 2
This opportunity to be of service is sincerely appreciated. If you have any questions, please
call this office.
Sincerely,
HETHERINGTON ENG INEERING, rNC.
Mark D. Helheringt
Civil Engineer 3048
Geotechnical Engine
(expires 3/3 1/22)
Distribution: 3-Addressee
P.
111 . Cunningha1
ii Engineer 81687
,-pires 3/3 1/22)
I-v ia e-mail (ronseverino44@g111ail.co111)
I-via e-mai l (larry-aliclad e@att.net)
HETHERINGTON ENGINEERING, INC.
REFERENCES
1. "Geotechnical Investigation, Proposed Retaining Wall, 4100 Sunny Hill Drive,
Carlsbad, California", by Hetherington Engineering, Inc., elated November 25, 2020.
2. "Site Plan and Demolition Plan, Glesmann Residence, 4100 Sunny Hill Drive,
Carlsbad, California" by Raymond Sharpe, elated September 24, 2020.
HETHERINGTON ENGINEERING, INC.
Project No. 9235. l
Log No. 21279