HomeMy WebLinkAboutUpdated Geotechnical Study
I
I
1
1
I
"I
1
-I
I
1
I
I
1
I
1
I
1
1
_I
~"". ~~~_c ;~%~~C - C j5i1iic :ift_
J I I I Ie.
=- .!!WI!ImUWOO--------~v-- ~-
'"
, ""
'"
EnGEN Corporation . Soil Engineering. Testing. Constructlon Materials Testing. Laboratory Testing.
. Environmental Site Assessments. Hazardous Materials Site Cleanup.
c Environmental and Geotechnical Engineering Network Corporation . SpeciollnspeCTIons . Geology' Englneerlng Geology .
January 26, 1998
Westside City Associates, LLC
41975 Winchester Road
Temecula, California 92590
(909) 693-1430 {Fax (909) 693-1429
Attention: Mr. Bill [)endy
Regarding: UPDATED GEOTECHNICAL STUDY
Tract Numbers 21383,24085,28471,28743,28657 and 25139
City of Temecula, County of Riverside, California
Project Number: T1330-UGS
References: 1. EnGEN Corporation, Geotechnical Report of Rough Grading Plan, Lots 1-10
of Parcel Map 24085, Diaz Road, City of Temecula, County of Riverside,
California, Project Number: T1075-C, report dated December 19, 1996.
2. EnGEN Corporation, Updated Geotechnical/Geological Engineering Study,
Proposed Expansion of Existing Business Center, Parcels 1 through 10 of
Parcel Map 24085, Diaz Road, City of Temecula, County of Riverside,
California, Project Number: T1075-GS, report dated August 19,1996.
3. Geosoils, Inc., Supplemental Geotechnical Investigation of Lots 14 through
22, Phase I of Tentative Parcel Map 24085, City of Temecula, County of
Riverside, California, report dated May 4, 1994.
4. Schaefer Dixon Associates, Inc., Geotechnical Mass Grading Report No.2,
Parcel Map Number 21383 (Core I, Phase II), City of Temecula, County of
Riverside, California, report dated January 7, 1992.
5. Schaefer Dixon Associates, Inc., Geotechnical Mass Grading Report No.1,
Parcel Map Number 21383 (Core I, Phase I), City of Temecula, County of
Riverside, California, report dated August 1, 1991.
6. Schaefer Dixon Associates, Inc., Reporl on Geotechnical Investigation,
Assessment District No. 155, Parcel Map 24085, 24086, 21029, 21382 and
21383, Rancho California, County of Riverside, California, report dated June 7,
1989.
7. Leighton and Associates, Report on Preliminary Geotechnical Investigation,
Proposed Industrial/Commercial site west of Cherry Street and Diaz Road,
A.D. No. 155, Rancho California, County of Riverside, California, report dated
June 23, 1986.
Dear Mr. Dendy:
Per your request and signed Proposal, a representative of this firm reviewed the referenced
previous reports and visited the subject site on January 15, 1998, to visually
Corporate Office
41607 Enterprise Circle North, Suite 1
Temecula, CA 92590
(909) 676-30951 Fax: 676-3294
Web-page address: www.engencorp.com
E-mail address:engencorp@pe.net
Orange County Office
2615 Orange Avenue
Santa Ana_ CA 92707
(714) 546-4051/ Fax: 546-4052
\
I
I
1
1
.
1
".
.
I
I
1
1
1
I
I
.
I
I
I
Westside City Associates, LLC
Project Number: T1330-UGS
January 1998
Page 2
observe and probe the surface within the subject tract, in order to update the reports referenced
above.
1.0 EXECUTIVE SUMMARY
1.1 Tract 21383.24085.28471-1 and 2. and Tract 28743: These tracts have been
previously graded into individual lots. All lots appear to be buildable as is, with
relatively minor grading. Depending on planned development, minor grading
should consist of either minor scarification of existing grades or overexcavation of
cut/fill transition lots. Depending on planned development, foundations may
consist of conventional column footings and continuous wall footings.
1.2 Tracts 28657 and 25139: As of the writing of this report, these tracts exist in a
natural condition with relatively little or no previous grading. Geotechnical
investigations will be required on these tracts prior to grading. Based on
experience from nearby properties, the development of these tracts should be
feasible.
2.0 GENERAL EARTHWORK RECOMMENDATIONS
Depending on planned development, the existing lots should need only minor regrading. In
general, if fill underlies the lot and proposed grades are to remain the same (or if proposed
grades are greater than existing grades), then only 12-inches of scarification and
recompaction are expected to be required. If a cut/fill transition runs through the lot, then
the cut portion. will need to be overexcavated a minimum of three (3) feet and then
recompacted (depending on proposed development).
Specific earthwork
recommendations should be made when grading plans become available.
3.0 STRUCTURAL FILL
All fill material, whether on-site material or import, should be approved by the Project
Geotechnical Engineer and/or his representative before placement. All fill should be free
EnGEN Corporation
-v
I
I
1
1
1
1
'1
I
I
I
I
I
I
1
1
1
I
I
I
5.0
Westside City Associates, LLC
Project Number; T1330-UGS
January 1998
Page 3
from vegetation, organic material, and other debris. Import fill should be no more
expansive than the existing on-site material. Approved fill material should be placed in
horizontal lifts not exceeding 6.0 to 8.0-inches in thickness and watered or aerated to
obtain near-optimum moisture content (:t 2.0 percent of optimum). Each lift should be
spread evenly and should be thoroughly mixed to ensure uniformity of soil moisture.
Structural fill should meet a minimum relative compaction of 90 percent of maximum dry
density based upon ASTM D1557-78 (90) procedures. Moisture content of fill materials
should not vary more than 2.0 percent of optimum, unless approved by the Project
Geotechnical Engineer.
4.0
GENERAL FOUNDATION RECOMMENDATIONS
Depending on planned development, foundations may consist of conventional column
footings and continuous wall footings. Reinforcement of footings and slabs is dependant
on several factors, including local soil expansion characteristics, and will need to be
determined on a lot by lot basis. Specific foundation recommendations should be made
when proposed development plans becomes available.
GENERAL RECOMMENDATIONS
5.1 Utility Trench Recommendations: Utility trenches within the zone of influence of
foundations or under building floor slabs, hardscape, and/or pavement areas should
be backfilled with properly compacted soil. It is recommended that all utility
trenches excavated to depths of 5.0-feet or deeper be cut back to an inclination not
steeper than 1: 1 (horizontal to vertical) or be adequately shored during construction.
Where interior or exterior utility trenches are proposed parallel and/or perpendicular
to any building footing, the bottom of the trench should not be located below a 1:1
plane projected downward from the outside bottom edge of the adjacent footing
EnGEN Corporation
?
I
1
1
I
1
1
1
1
I
I
1
1
I
1
1
1
I
I
1
Westside City Associates, LLC
Project Number: T1330-UGS
January 1998
Page 4
unless the utility lines are designed for the footing surcharge loads. Backfill material
should be placed in a lift thickness appropriate for the type of backfill material and
compaction equipment used. Backfill material should be compacted to a minimum
of 90 percent relative compaction by mechanical means. Jetting of the backfill
material will not be considered a satisfactory method for obtaining compaction.
Maximum dry density and optimum moisture content for backfill material should be
determined according to ASTM D1557-78(90) procedures.
5.2 Temporary Excavations or Cuts: All temporary cuts and excavations should be
made in accordance with CAUOSHA minimum requirements for Type C soil. If
site restrictions require a different configuration, this office should be contacted to
develop construction recommendations.
5.3 Finish Lot Drainaae: Finish lot surface gradients in unpaved areas should be
provided next to tops of slopes and buildings to direct surface water away from
foundations and slabs and from flowing over the tops of slopes. The surface water
should be directed toward suitable drainage facilities. Ponding of surface water
should not be allowed next to structures or on pavements. In unpaved areas, a
minimum. positive gradient of 2.0 percent away from the structures and tops of
slopes for a minimum distance of 5.0-feet and a minimum of 1.0 percent pad
drainage off the property in a nonerosive manner should be provided.
5.4 Planters: Planters around the perimeter of the structure should be designed to
ensure that adequate drainage is maintained and minimal irrigation water is allowed
to percolate into the soils underlying the building.
5.5 Pre-Bid Conference: It is recommended that a pre-bid conference be held with
the owner or an authorized representative, the Project Architect, the Project Civil
Engineer, the Project Geotechnical Engineer and the proposed contractors present.
EnGEN Corporation
~
I
I
1
I
1
1
I
I
1
I
I
I
1
1
1
I
1
1
1
6.0
Westside City Associates, LLC
Project Number: T1330-UGS
January 1998
Page 5
This conference will provide continuity in the bidding process and clarify questions
relative to the supplemental grading and construction requirements of the project.
5.6 Pre-Gradinq Conference: Before the start of any grading, a conference should be
held with the owner or an authorized representative, the contractor, the Project
Architect, the Project Civil Engineer, and the Project Geotechnical Engineer
present. The purpose of this meeting should be to clarify questions relating to the
intent of the supplemental grading recommendations and to verify that the project
specifications comply with the recommendations of this geotechnical engineering
report. Any special grading procedures and/or difficulties proposed by the
contractor can also be discussed at that time.
CONSTRUCTION OBSERVATIONS AND TESTING
Supplemental grading of the property should be performed under engineering observation
and testing performed by EnGEN Corporation. Supplemental grading includes, but is not
limited to, overexcavation cuts, fill placement, and excavation of temporary and permanent
cut and fill slopes. In addition, EnGEN Corporation should observe all foundation
excavations. Observations should be made before installation of concrete forms and/or
reinforcing steel to verify and/or modify the conclusions and recommendations in this
report. Observations of overexcavation cuts, fill placement, finish grading, utility or other
trench backfill, hardscape subgrade, pavement subgrade and base course, retaining wall
backfill, slab presaturation, or other earthwork completed for the subject development
should be performed by EnGEN Corporation if requested by the local building authority,
or owner / developer. If the observations and testing to verify site geotechnical conditions
are not performed by EnGEN Corporation, liability for the performance of the
development is limited to the actual portions of the project observed and/or tested by
EnGEN Corporation. If parties other than EnGEN Corporation are engaged to perform
/'
'J
EnGEN Corporation
I
I
1
1
I
1
I
I
I
I
1
1
1
1
1
I
1
I
1
Westside City Associates, LLC
Project Number: T1330-UGS
January 1998
Page 6
soils and materials observations and testing, they must be notified that they will be
required to assume complete responsibility for the geotechnical aspects of the project by
concurring with the recommendations in this report or providing alternative
recommendations.
7.0
CLOSURE: This report has been prepared for use by the parties or project named or
described in this document. It mayor may not contain sufficient information for other
parties or purposes. In the event that changes in the assumed nature, design, or location
of the proposed structure and/or project as described in this report, are planned, the
conclusions and recommendations contained in this report will not be considered valid
unless the changes are reviewed and the conclusions and recommendations of this report
modified or verified in writing. This study was conducted in general accordance with the
applicable standards of our profeSSion and the accepted soil and foundation engineering
principles and practices at the time this report was prepared. No other warranty, implied
or expressed beyond the representations of this report, is made. Although every effort has
been made to obtain information regarding the geotechnical and subsurface conditions of
the site, limitations exist with respect to the knowledge of unknown regional or localized
off-site conditions that may have an impact at the site. The recommendations presented
in this report are valid as of the date of the report. However, changes in the conditions of
a property can occur with the passage of time, whether they are due to natural processes
or to the works of man on this and/or adjacent properties. If conditions are observed or
information becomes available during the design and construction process that are not
reflected in this report, or the referenced reports, EnGEN Corporation should be notified
so that supplemental evaluations can be performed and the conclusions and
recommendations presented in this report can be modified or verified in writing. Changes
in applicable or appropriate standards of care or practice occur, whether they result from
EnGEN Corporation
<e
I
1
I
I
1
I
I
I
1
1
1
1
I
1
I
I
1
I
I
~
Westside City Associates, LLC
Project Number: T1330-UGS
January 1998
Page 7
legislation or the broadening of knowledge and experience. Accordingly, the conclusions
and recommendations presented in this report may be invalidated, wholly or in part, by
changes outside of the control of EnGEN Corporation which occur in the future.
Thank you for the opportunity to provide our services. Often, because of design and constnuction
details which occur on a project, questions arise concerning the geotechnical conditions on the
site. If we can be of further service or you should have questions regarding this report, please do
not hesitate to contact this office at your convenience. Because of our involvement in the project
to date, we would be pleased to discuss engineering testing and observation services that may be
applicable on the project.
Respectfully submitted,
EnGEN Corporation,
TZ4:;;, CEG 197
Principal Engineering Geologist
Expi res 11-30-99
TD/OB/ch
Distribution: (4) Addressee
Wayne O\REPORTS\GS\T1330UGS Westside City Associates
EnGEN Corporation
\