HomeMy WebLinkAboutCT 01-04; CALAVERA HILLS VILLAGE U; GEOTECHNICAL UPDATE PHASE 9; 2005-04-25CT C!-04
Geotechnical • Geologic. Environmental
5741 Palmer Way • Carlsbad, California 92008 • (760)438-3155 • FAX (760) 931-0915
- April 25, 2005
. W.O. 4067-C-SC
Brookfield Homes
.12865 Pointe Del Mar, Suite 200 ..
Del Mar, California 92014 .
.
Attention Ms Teri McHugh
Subject: Geotechnical Update for' Phase 9, Building Lots 36, 41; 47, 48, and 49,
Village U, Calavera Hills II Carlsbad San Diego County, California
Dear Ms McHugh
In accordance with your request, GeoSoils, Inc. (GSI) has reviewed the referenced reports
- (seethe Appendix) with respect to as-graded site conditions and has prepared this revised
update report. Grading and processing of original ground within the subject building pads
was observed and selectively tested by a representative of GSI during the earthwork phase
of development for the subject property, including a recent phase of grading which,
resulted in additional cut excavation across the building pads and proof rolling
(compaction) of the exposed subgrade to a minimum 90 percent relative compaction.
Based on our observations and testing, the area is generally considered suitable for its
intended residential use. Geotechhicál observations and testing, performed during the
initial phase of site grading, and completed by this office, are summarized in GSI (2004b).
Based on our observations (including the most recent phase of cut excavation), .the
findings, conclusions, and recommendations presented in our referenced reports (see the .
Appendix), including GSI (2003 and 2004b), are generally considered suitable with respect
to the construction and development of the subject building pads. Conditioning and/or
prewetting of. slab and foundation areas is recommended, as indicated in GSI (2003,
2004a, and 2004b). Unless specifically superceded herein, the' conclusions arid
recommendations contained in those reports (GSI, 2003,. 2004a and 2004b) are
considered valid and applicable and should be appropriately implemented
SUMMARY OF RECOMMENDATIONS REGARDING . V •
GEOTECHNICAL OBSERVATION AND TESTING
We recommend' that observation and/or testing be performed by GSI t each of the
following construction stages
During grading/recertification.
During excavation.
During placement of subdrains, toe drains, or other subdrainage devices, prior to
placing fill and/or backfill.
After excavation of building footings, retaining wall footings, and free standing walls
footings, prior to the placement of reinforcing steel or concrete.
Prior to pouring any slabs or flatwork, after presoaki n g/presatu ration of building
pads and other flatwork subgrade, before the placement of concrete, reinforcing
steel, capillary break (i.e., sand, pea-gravel, etc.), or vapor barriers (i.e., visqueen,
etc.).
During retaining wall subdrain installation, prior to backfill placement.
During placement of backfill for area drain, interior plumbing, utility line trenches,
and retaining wall backfill.
During slope construction/repair.
When any unusual soil conditions are encountered during any construction
operations, subsequent to the issuance of this report.
When any developer or homeowner improvements, such as flatwork, spas, pools,
walls, etc., are constructed, prior to construction.
A report of geotechnical observation and testing shall be provided at the conclusion
of each of the above stages, in order to provide concise and clear documentation
of site work, and/or to comply with code requirements.
GSl shall review project sales documents tO homeowners/homeowners associations
for geotechnical aspects, including irrigation practices, the conditions outlined
above, etc., prior to any sales. At that stage, GSI will provide homeowners
maintenance guidelines which shall be incorporated into such documents.
OTHER DESIGN PROFESSIONALS/CONSULTANTS
The design civil engineer, structural engineer, post-tension designer, architect, landscape
architect, wall designer, etc., shall review the recommendations provided herein,
incorporate those recommendations into all their respective plans, and by explicit
reference, make this report part of their project plans. This report presents minimum
Brookfield Homes W.O. 4067-C-SC
Village U, Phase 9, Calavera Hills April 25, 2005
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GeoSoils, Inc.
design criteria for the design of slabs, foundations and other elements possibly applicable
to the project. These criteria shall not be considered as substitutes for actual designs by
the structural engineer/designer. Please note that the recommendations contained herein
are not intended to preclude the transmission of water or vapor through the slab or
foundation. The structural engineer/foundation and/or slab designer shall provide
recommendations to not allow water or vapor to enter into the structure so as to cause
damage to another building component, or so as to limit the installation of the type of
flooring materials typically used for the particular application.
The structural engineer/designer shall analyze actual soil-structure interaction and
consider, as needed, bearing, expansive soil influence, and strength, stiffness and
deflections in the various slab, foundation, and other elements in order to develop
appropriate, design-specific details. As conditions dictate, it is possible that other
influences will also have to be considered. The structural engineer/designer shall consider
all applicable codes and authoritative sources where needed. If analyses by the structural
engineer/designer result in less critical details than are provided herein as minimums, the
minimums presented herein shall be adopted. It is considered likely that some, more
restrictive details will be required.
If the structural engineer/designer has any questions or requires further assistance, they
shall not hesitate to call or otherwise transmit their requests to GSI. In order to mitigate
potential distress, the foundation and/or improvement's designer shall confirm to GSI and
the governing agency, in writing, that the proposed foundations and/or improvements can
tolerate the amount of differential settlement and/or expansion characteristics and other
design criteria specified herein.
PLAN REVIEW
Final project plans (grading, precise grading, foundation, retaining wall, landscaping, etc.),
shall be reviewed by this office prior to construction, so that construction is in accordance
with the conclusions and recommendations of this report; Based on our review,
supplemental recommendations and/or further geotechnical studies may be warranted.
Brookfield Homes W.O. 4067-C-SC
Village U, Phase 9, Calavera Hills April 25, 2005
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GeoSoils, Inc.
LIMITATIONS
The materials encountered on the project site and utilized for our analysis are believed
representative of the area; however, soil and bedrock materials vary in character between
excavations and natural outcrops or conditions exposed during mass grading. Site
conditions may vary due to seasonal changes or other factors.
Inasmuch as our study is based upon our review and engineering analyses and laboratory
data, the conclusions and recommendations are professional opinions. These opinions
have been derived in accordance with current standards of practice, and no warranty,
either express or implied, is given. Standards of practice are subject to change with time.
GSI assumes no responsibility or liability for work or testing performed by others, or their
inaction; or work performed when GSI is not requested to be onsite, to evaluate if our
recommendations have been properly implemented. Use of this report constitutes an
agreement and consent by the user to all the limitations outlined above, .notwithstanding
any other agreements that may be in place. In addition, this report may be subject to
review by the controlling authorities. Thus, this report brings to completion our scope of
services for this portion of the project.
Brookfield Homes W.O. 4067-C-SC
Village U, Phase 9, Calavera Hills April 25, 2005
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GeoSoils, Inc.
Principal Engineer,
S. . The opportunity to be of service is greatly appreciated. If you have any questions, please
do not hesitate to call our office.
Respectfully submitted,
GeoSoils, Inc.
Robert G. Crisman
Engineering Geologist, CEG 1934
RGC/ATG/JPF/jk
Attachment: Appendix - References
Distribution: (2) Addressee
Brookfield Homes W.O. 4067-C-SC
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GeoSoils, Inc.
APPENDIX
REFERENCES
GeoSoils, Inc., 2004a, Response to plan check comments, Village U of Calavera Hills II,
City of Carlsbad, San Diego County, California, W.O. 4067-C-SC, dated October 7.
2004b, Report of rough grading, Calavera Hills, Village U, Building lots 29 through
54, and Active Recreation Area, Carlsbad Tract 01-04, Drawing 407-6A, Carlsbad,
San Diego County, California, W.O. 3459-131-SC, dated September 15.
2003, Geotechnical update and grading plan review, Calavera Hills, Village U,
Carlsbad Tract 01-02, City of Carlsbad, San Diego County, California, dated
September 29.
Hunsaker and Associates, San Diego, Inc., 2003, Grading plans for Calavera Hills
Village U, Carlsbad• Tract 01-03, Drawing No. 407-06, J.N. 0227, dated
December 16.
International Conference of Building Officials, 2001, California building code, California
Code of Regulations, Title 24, Part 2, Volume 2, California Building Standards
Commission, Adopted November 1, 2002.
1997, Uniform building code.
GeoSoils, Inc.