HomeMy WebLinkAboutCT 00-16; Poinsettia Properties; Addendum to Geotechnical Investigation; 2001-03-28GEOCON
INCORPORATED
GEOTECHNICAL CONSULTANTS
Project No. 06514-12-01
March 28, 2001
John Laing Homes
895 Dove Street, Suite 110
Newport Beach, California 92660
Attention: Mr. Gregg Foster
Subject: POINSETTIA PROPERTY
(PLANNING AREAS 2, 3, AND 4)
CARLSBAD, CALIFORNIA
PLAN REVIEW AND COMMENT RESPONSE
Reference: 1.
2.
CTOO-16/PUD 01-01/SDP 00-12/CDP 00-44 Poinsettia Properties, PA 2, 3, & 4,
plan review comments prepared by the City of Carlsbad Planning Department,
dated February 8, 2001.
Tentative Map Poinsettia Property (Planning Areas 2, 3, & 4), prepared by
Hunsaker & Associates San Diego Inc., resubmitted date March 27, 2001.
Update Geotechnical Investigation, Poinsettia Property, Carlsbad, California,
prepared by Geocon Incorporated, dated July 20, 2000 (Project No. 06514-12-01).
Gentlemen:
In accordance with the request of Mr. Ron Grunow and Hunsaker & Associates, we have prepared
this letter in response to geotechnical-related comments presented in the referenced plan review. To
aid in preparing this response, we have reviewed the referenced tentative map. Our response is
presented below utilizing the same plan review comment number for case in reference.
Comment No. 8. Typical Lot Drainage: Surface runoff flow line may be reduced to 3 feet as
measured horizontally from foundation edge provided foundations are deepened to maintain proper
footing embedment. The civil engineer should calculate the portion of the footing requiring
deepening and the extended depth and present this information on the precise plot plans. During
observation of the foundation excavations to be conducted in the field by Geocon Incorporated, the
deepened foundation requirement will be verified.
Comment No. 10, Errata: Section 5.4 of the referenced project geotechnical report dated July 20,
2000 should be corrected to replace the word "more" with "none". Those parties holding copies of
this report may make a pen/ink correction or insert a replacement page attached.
6960 Flanders Drive • San Diego, California 92121-2974 • Telephone (858) 558-6900 • Fax (858) 558-6159
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Should you have any questions regarding this correspondence, or if we may be of further assistance,
please contact the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
RCE 56418
AS:KPA:dmc
Attachment: Section 5.4 (page
(2) Addressee
(2) Hunsaker & Associates
Attn: Ron Grunow
CERTIFIED
ENGINEERINGGEOLOGIST
08/31/01
Project No. 06514-12-01 -2-March 28, 2001
It is our opinion that the site could be subjected to moderate to severe ground shaking in the event of
a major earthquake along any of the above mentioned faults, however, the seismic risk at the site is
not considered to be significantly different than that of the surrounding developments of similar
geologic settings in the Carlsbad area.
5.2 Seismic Design Criteria
The following table summarizes site specific seismic design criteria obtained from the 1997 Uniform
Building Code (UBC). The values listed in Table 5.2 are for the Rose Canyon Fault (located
approximately 4 miles west of the site) which is identified as a Type B fault and is more dominant
than the nearest Type A fault (Elsinore) due to its close proximity to the site.
TABLE 5.2
SEISMIC DESIGN PARAMETERS
Parameter
Seismic Zone Factor, Z
Soil Profile Type
Seismic Coefficient, Ca
Seismic Coefficient, Cv
Near-Source Factor, Na
Near-Source Factor, Nv
Seismic Source
Value
0.40
Sc
0.40
0.65
1.0
1.2
B
UBC Reference
Table 16-1
Table 16-J
Table 16-Q
Table 16-R
Table 16-S
Table 16-T
Table 16-U
5.3 Liquefaction
Liquefaction occurs in loose cohesionless soils located below the water table that are subjected to
large accelerations during strong earthquakes. Due to the dense nature of the formational units, the
removal and recompaction of the surficial soils, and the lack of a permanent ground water table, the
potential for liquefaction of the site subsoils is considered to be very low.
5.4 Landslides
Based on the geologic reconnaissance and the exploration excavations, there are no landslides
present on the site and more none are to known to exist in near proximity that would impact the
proposed development.
Project No. 06514-12-01 July 20, 2000