HomeMy WebLinkAboutParcel 16 Geotechnical Investigation
;~.....
II., ~.;-~'; "
'. ~ '.
. .
""~
'i,.;/
14"1-\
,
~.
II.
~
..
..
..
II
..
.
I(
II
..
II
.
.
.
.
II
.
(C(Q)[Plf ' ~
l,V
.0\
GEOTECHNICAL REPORT r"'
PROPOSED WAREHOUSE BUILDING
BASICS ETC.
WT 16 PARCEL MAP 23561-2
TEMECULA, CALIFORNIA
"
Prepared for:
Basics Etc. Corporation
43300 Bl Business Park Drive
Temecula, California 92590
Prepared by:
"
"
I
,
Schaefer Dixon Associates
A Huntingdon Company 'I :
, 22 Mauchly ,
Irvine, California 92718'
i
,
,
30.066 I'
"
I'
October 8, 1993
.,
\
i"
I &~, .
, .~" :Hlll!!mgQ!!l!
I
I
I
I
~
t
.
~
{
: '<~.>Sch8eIBr Dixon AssociAtes,lnc.
,
22 Mauchly
Irvine. Californiil 92718
171<111/.3113
fa<- 17141127-3347
30-066
October 8, 1993
Basics Etc. Corporation
43300 Bl Business Park Drive
Temecula, California 92590
Attention: Mr. John Kupka
Subject:
Geotechnical Report
Proposed Warehouse Building
Basics Etc. .
Lot 16, Parcel Map 23561-2
Temecula, California
Gentlemen,
Transmitted herewith is Schaefer Dixon Associates' (SDA's) geotechnical report for the proposed
warehouse building located within the Jefferson Business Park, Temecula, California.
1
.
.
II
~
*
.
.
.
This report has been prepared in accordance with our proposal dated September 2, 1993. The
authorized scope of work included review of existing geotechnical data, laboratory testing,
engineering analysis, and preparation of this report. i
Thank you for the opportunity to be of service. If you should have any questions regarding this
report, or if you need additional information, please call either of the undersigned.
(C(Q)[PV
ame J. ver, G.E.
Senior Vice President
Director, Geotechnical Servioes
n J. Butelo C.E.G.
Chief Geologist
Distribution: (2)
(6)
Addressee
Jeff Hardy and Associates
Attention: Mr. Jeff Hardy
1I:\Il.PT\XlO66.ROI
-1-
A.......r-"llllhrlllIH!w'.!lI'OI(Ilrtl['.1l\'es
o
v
..
I-
.
.
..
II
.
.:
.
.
.
iI
.
.
.
.
.
ill
.
_i ;,
,-~-'
,
Basics Etc. Corporation
30-066
October 8, 1993
Schaefer Dixon Associates
A Huntingdon Compan]
; ,
TABLE OF CONTENTS
SECTIONS
PAGE NO.
, I
1.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1
2.0 PROJECT DESCRIPTION .................................... 1
3.0 GEOTECHNICAL BACKGROUND ............................. 2
4.0 SITE CONDmONS ....................................... 2
4.1 GEOLOGIC SETTING . . . . . . . . . . . . . ; . . . . . . . . . . . . . . . . .. 2
4.2 FAULTING AND SEISMICITY . . . . . . . ; . .. . . . . . . . . . . . . . .. 2
4.3 AS-GRADED GEOTECHNICAL..CONDmONS . . . . . . . . . . . . . . .. 2
4.4 LABORATORY TESTING ............................. 3
5.0 CONCLUSIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3
6.0 DESIGN RECOMMENDATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3
6.1 EARTHWORK... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3
6.1.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3
6.1.2 Site Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3
6.1.3 Fill Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4
6.1.4 Compaction ................................. 4
6.2 FOUNDATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4
6.2.1 Bearing Capacity ............................... 4
6.2.2 Settlement ................................... 5
6.2.3 Lateral Load Resistance . . . . . . . . . . . . . . . . . . . . . . . . . .. 5
6.2.4 Expansive Soil Conditions ....... '. . . . . . . . . . . . . . . . .. 5
6.3 CONCRETE SLABS-ON-GRADE . . . . . . . . . . . . . . . . . . . . . . . .. 5
6.4 RETAINING WALLS ................................. 6
6.4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6
6.4.2 Lateral Earth PreSsures .........!.................. 6
6.4.3 Backfill . . . . . . . . . . . . . . . . . . .'. . . . . . . . . .. . . . . . . .. 7
6.4.4 Wall Backdrains : . . . . . . . . . . . . .' . . . . . . . . . . . . . . .'. .. 7
I
6.5 PAVEMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . .. 7
6.5.1 Subgrade . . . . ~ . . . . . . . . . . . . . . . ; . . . . . . . . . . . . . .. 7
6.5.2 Asphalt Concrete Pavement. . . . . . .'. . . . . . . . . . . . . . . . .. 7
6.5.3 ConcretePavementandPlatwork .. .'.................. 8
6.6 UTILITY TRENCH BACKFILL. . . . . . . .'. ; ,; . . . . . . . . . . . . . .. 9
6.7 CORROSION PROTECTION. . . . . . . . . ,I. . . . . . . . . . . . . . . . .. 9
I
1l:IJlYI\)OlJ66.ROI
-i-
'7
.- '? '.
.. .
.'
.
.
.
.
.
.
.
(
.
.
.
.
.
.
.
,
.
......~.~
-"
Basics Etc. Corporation
30-066
October 8, 1993
Schaefer Dixon Associates
A Huntingdon Compan]
TABLE OF CONTENTS (continued)
SECTIONS PAGE
6.8 srrn DRAIN"AGE . . . . . . . . . . . . . . . . ~ . . . . . . . . . . . . . . . . .. 9
6.9 GROUNDWATER CONSIDERATION ....................... 9
7.0 CONSTRUCTION CONSIDERATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7.1 TEMPORARY EXCAVATIONS. . . . . . . . .. . . . . . . . . . . . . . . . . 10
7.2 EXCAVATION CHARACTERISTICS ......................10
8.0 GEOTECHNICAL CONSTRUCTION SERVICES . . . . . . . . . . . . . . . . . . . .. 10
: I
I
9.0 CLOSURE ............................................. 10
REFERENCES ...........................:.................. 11
LIST OF TABLES
i
Table 1 - Summary of Laboratory Testing ...........:................... 3
,
Table 2 - Asphalt Concrete Pavement Structural Sections . . ~ . . . . . . . . . . . . . . . . . . 8
I
,
1I:\JlP'1'\)(X)66.ROI
-ii-
~.
II ,'? .
...
..
ill
..
ill
ill
ill
-
i{
--
it
II(
II
..
II
..
iI
-
\
'...J
.,.~,.
f',\,)
-:~
Basics Etc. Corporation
30-066
October 8, 1993
Schaefer Dixon Associates
A Huntingdan Compan]
1.0 INTRODUCTION :
I
This report presents geotechnical recommendations by Schaefer Dixon Associates (SDA) for
design of the proposed warehouse building to be located within the Jefferson Business Park in
the City of Temecula, California.
The objectives of our investigation were to evaluate the nature and engineering properties of
subsurface materials, and to develop geotechnical parameters for earthwork, site development,
and design of foundations and pavements. The authorized scope of work included review of
geotechnical data/reports pertinent to the subject site, laboratory testing of representative near-
surface soil samples, geotechnical engineering analysis, and preparation of this report.
,
"
This report has been prepared for Basics Etc. Corporation and their consultants, to be used
solely in design of the project as described within this report. This report may not contain
sufficient information for other projects or for the purposes of other parties.
2.0 PROJECT DESCRIPTION
The project site is located northwest of and adjacent to McCabe Court, approximately 330 feet
southwest of Madison Avenue. The subject site is designated as Parcel 16 of Parcel Map 23561-
2. This parcel is a portion of the Jefferson Business Park,
Based on development plans prepared by Jeff Hardy and Associates Architecture, the project will
include the construction of a warehouse-type building. The proposed building will be a one-
story concrete, tilt-up structure with slabs-on-grade. The building will occupy a roughly
rectangular area of approximately 17,300 feet. Other improvements associated with the
proposed development will include retaining structures, driveways, parking spaces, a trash
enclosure, and landscape areas. '
Maximum column loads for the proposed warehouse building, including both dead and live
loads, will be about 70 kips. Perimeter wa1l10ads are not expected to be greater than 4 kips per
lineal foot. The retaining structures are anticipated to be concrete block construction with
heights up to about 4 feet.
Minor earthwork involving cut and fill within the site is expected to be required to accomplish
final design grade and facilitate surface drainage.
1I:\R.Yl"\3lJ06oS.ROI
-1-
-b
I"
I
I
I
I
I
I
I
I
,
,
,
I
,
,
I
I
I
,
"=' '~
. '\
'......,,"
,
'-.-'"
Basics Etc. Corporation
30-066
October 8, 1993
Schaefer Dixon Associates
A Huntingdon Compan]
3.0 GEOTECHNICAL BACKGROUND
Geotechnical investigations of the site and nearby parcels were performed previously by Schaefer
Dixon Associates. Complete titles and dates of the referenced reports are listed in the
"References" following the text of this report.
The site was rough graded by Bedford Properties with geotechnical observation and testing
services provided by SDA in 1989 (Reference 2).
4.0 SITE CONDITIONS
4.1 GEOWGIC SETTING
The Temecula Valley consists of a topographic and structural trough or "graben," bounded by
relatively low hills on the northeast and by steep rugged slopes of the Elsinore Mountains to the
west and southwest. Prior to rough grading, the site consisted of gently rolling terrain, dissected
by intervening, westerly flowing drainage channels.
Geologic units at the site consist of approximately 6 feet of compacted fill overlying sandy silt
and silty sand layers with gravel of the Pauba Formation.
4.2 FAULTING AND SEISMICITY
The project site is located in the highly-seismic southern California area within the regional
influence of several active or potentially active fault systems. Previous investigation activities
have demonstrated that active faults (Le. faults with surface displacement during the past 11,000
years) do not transect the subject development (Reference 1).
As currently documented, the major seismically active fault closest to the project site is the
Wildomar fault located less than a mile to the west of the site. Several other seismically active
faults/fault zones that may affect the site include the San Jacinto fault located approximately 21
miles to the northeast, the San Andreas fault located approximately 36 miles to the northeast,
and the Newport-Inglewood fault approximately 24 miles to th,e west.
'i
4.3 AS-GRADED GEOTECHNICAL CONDmONS ':
The site was previously mass graded in 1989. Approximately 6 feet of compacted fill materials
were placed within Parcel 16. A description of geotechnical conditions encountered during
grading is presented in the Schaefer Dixon Associates February 8, 1990 report (Reference 3).
1I:\RPnXlO66.ROI
-2-
Cp
II ~.'
. ,
-. .
.
II. ~
II
II
III
II
II
~
~
iL
..
iI.
l
..
..
..
I
iI
..
! ..':}
Basics Etc. Corporation
30-066
October 8, 1993
Schaefer Dixon Associates
A Huntingdon Camplln]
4.4
LABORATORY TESTING
A sample of surface materials exposed on the surface at the site was obtained by SDA. The
sample was tested in the laboratory to evaluate the potential for expansion in accordance with
Uniform Building Code (UBC) Standard No. 29-2, to evaluate concentrations of soluble sulfate
in accordance with California Test Method (CTM) 417 and to determine subgrade resistance in
accordance with ASTM D 2844. The test results are summarized in Table 1.
!
TABLE 1
SUMMARY OF LABORATORY TESTING
illll~llttlltl!i~l!il~t~11I1~~fllrtlf~llil~lr~II~1~lill!~Iil
17
72
7.0
5.0 CONCLUSIONS
Results of the geotechnical evaluation indicate that construction of the proposed warehouse
building described in this report is. geotechnicaJly feasible as planned, provided that
recommendations presented in the following sections are incorporated into project design and
specifications.
!'
6.0 DESIGN RECOMMENDATIONS
6.1
EARTHWORK
6.1.1 General
Earthwork, including excavation, backfill, and preparation of subgrade, should be performed in
accordance with applicable portions of the grading code of the City of Temecula, and the
geotechnical recommendations of this report. All earthwork should be performed under SDA's
observation and testing.
6.1.2 Site Preparation
The site should be cleared of vegetation, debris, and other deleterious materials.
of such materials should be removed and disposed of offsite.
Concentrations
1I:\AFJ'\J00(,6.ROI
-3-
~
. '. ~ '.
:.
.
t
.
.
j]
(
l
l
t
l
l
I
I
I
I
.
.
.
.'1....
Basics Etc. Corporation
30-066
October 8, 1993
Schaefer Dixon Associates
A Huntingdon Compan]
Within the building area and 3 feet beyond the building perimeter, the pad should be
overexcavated to a depth of 1 foot below proposed pad grade. This area should be scarified to
a depth of about 6 inches, brought to slightly over optimum moisture content, then recompacted
as described under Section 6.1.4 for general fIll materials. Additional fill placed to achieve the
subpad elevation should also be placed in accordance with Section 6.1.4 for general fill material.
In remaining areas beyond the building pad, areas requiring additional fill should be scarified
6 inches, moisture conditioned to slightly over optimum moisture content, then recompacted in
accordance with Section 6.1.4 for general fill materials. However, final extent of reconditioning
should be evaluated during grading by SDA. Areas of proposed cut less than 12 inches in depth
should be cut to grade then prepared in the manner described above for fill areas. Areas of
proposed cut greater than 1 foot ,will likely not require ground preparation.
6.1.3 Fill Material
Onsite soils may be used as compacted fill, provided that they are free of organics, other
deleterious materials, or materials greater than 6 inches in size. At this time, near surface
import soils, if needed, should have an E.I. less than 70 as determined by UBC Standard No.
29-2. Proposed import soils should be provided to SDA for evaluation prior to use.
6.1.4 Compaction
Fill materials should be moisture conditioned generally to within 2 to 3 percent above optimum,
placed in horizontal lifts not exceeding 8 inches in thickness, and mechanically compacted to at
least 90 percent relative compaction. The laboratory maximum dry density and optimum
moisture content should be determined in accordance with ASTM D 1557-78.
6.2 FOUNDATIONS
6.2.1 Bearing Capacity
The proposed building may be supported by shallow foundations, including isolated and
continuous footings, embedded entirely in compacted fill materials. For design purposes, a
maximum allowable bearing pressure of 2,000 pounds-per-square-foot (pst) may be used.
Footings designed for the recommended bearing value should have a minimum embedment of
24 inches below lowest adjacent final grade. Minimum footing width should be 2 feet for
isolated footings and 1.5 feet for continuous footings. The above bearing values are for dead
plus live loads, and may be increased by one-third for transient loading conditions such as wind
and seismic loads. '
1I:~J{OI
-4-
:
,
~
.;-~ .
....
II
II
II
..
.
II
II
.
II
..
II
..
II
"
II
,
~
,
. ,
'~~.-"
Basics Etc. Corporation
30-066
October 8, 1993
Schaefer Dixon Associates
A Huntingdon Compan]
6.2.2 Settlement
Settlement of the ground is anticipated to occur as engineered fills and underlying materials
consolidate. Fill materials at the site have been in place for an extended period of time.
Consequently, we anticipate that the majority of settlement has taken place. Some subsidence
is expected to occur after construction of the ouilding. Based on geotechnical conditions
presented in the rough grade report (Reference 3), we anticipate the proposed warehouse
building may experience a maximum total settlement of 1 inch and a maximum differential
settlement of 1/4 inch over 30 to 40 feet between similarly-loaded, adjacent footings during the
next 50 years.
6.2.3 Lateral Load Resistance
Resistance to lateral loads may be developed by friction acting at the base of footings and
, passive earth pressure developed on the sides ofJootings below grade. Passive earth pressure
and friction may be used in combination, without reduction, in evaluating total resistance to
lateral loads.
An allowable coefficient of friction of 0.35 may be used for dead load forces for footings cast
directly against compacted fill. An allowable passive earth, pressure of 250 psf per foot of
footing embedment may be used for the sides of footings cast against compacted fill. The
maximum recommended allowable passive pressure is 2,000 psf. A 1/3 increase in the passive
pressure and frictional value may be used for transient loads such as wind and seismic forces.
6.2.4 Expansive Soil Conditions
Laboratory testing indicates that the onsite near-surface soils have a high potential for expansion.
In this regard, continuous footings should be reinforced with a minimum of two No.5 bars near
the top and two No. 5 bars near the bottom. Additional reinforcement may be required for
structural loads.
6.3 CONCRETE SLABS-ON-GRADE
Conventional concrete slabs-on-grade placed on compacted fills may be used for the proposed
construction. To help mitigate heaving of the slab from soil swell, we have recommended
placement of engineered fill having high moisture content. To maintain the desired soil
conditions below the slab, the pad surface should periodically be sprayed with water after
grading and until pouring of the slab to maintain a moist condition.
In addition to moisture conditioning, slabs-on-grade within lightly-loaded areas should have a
minimum thickness of 4 inches and should be reinforced with No.3 bars spaced at 24 inches
on centers, both ways. For design of slabs-on-grade to be constructed for heavier point loads,
1I:I.R.P1'\1OO6(i.ROI
-5-
C\
11.-
.
.
.
,
.
,
~
,
.
~
,
.
,
,
,
,
,
,
~ ..
.
"
;
,,-,/
i.~)
Basics Etc. Corporation
30-066
October 8, 1993
Schaefer Dixon Associates
A Huntingdon Compan]
i
a sub grade reaction modulus of 125 pounds-per-cubic-inch (pei) may be used. These slabs
should have a minimum thickness of 6 inches with No. 3 bars placed at slab mid-height at a
spacing of 18 inches on centers, both ways. Additional reinforcement may be required for
structural considerations. !
Floor slabs should be underlain by an impermeable polyethylene membrane where moisture
sensitive coverings are to be used. The membrane should be at least 6-mil thick and covered
by a minimum 2-inch thick layer of moistened (not saturated) Sand to both protect the membrane
and to promote proper concrete curing. A l-inch-thick layer of sand should be provided beneath
the membrane to provide a uniform surface on which the membrane can be placed.
6.4 RETAINING WALLS
6.4.1 General
Lateral earth pressures for retaining walls ate dependant on the type of soil used as backfill
behind the wall. Onsite soils are highly expansive and will therefore, tend to impose high lateral
pressures as they swell. Lower lateral pressures can be achieved by utilizing relatively
nonexpansive soils as backfill. Alternate lateral pressures have been provided below depending
on the backfill conditions.
6.4.2 Lateral Earth Pressures
. For design of retaining walls having level on site backfill materials, a triangular distribution of
lateral earth pressures determined by an equivalent fluid density of 50 pounds-per-cubic-foot
(pet) should be used for walls free to undergo some rotation (active case). Where these walls
are fIxed against rotation (restrained case), a triangular distribution determined by an equivalent
fluid density of 70 pcf should be used.
For design of retaining walls having level granular backfill, a triangular pressure distribution
determined by an equivalent fluid density of 30 pcf should be used for walls free to undergo
some rotation (active case). Where these walls are fIxed against rotation (restrained case), a
triangular distribution determined by an equivalent fluid density of 50 pcf should be used. The
granular backfill should be placed within a 1 to 1 projection up from the bottom of the wall and
to a height equal to the top of wall. The granular fIll should have an expansion index (EI, UBC
29-2) less than 20 and a sand equivalence (SE) of at least 25. The granular fill should be capped
with about 12 inches of onsite soils.
Surcharge pressure (dead or live) should be added to the above lateral earth pressures where
surcharge loads may occur adjacent to the wall. Surcharge pressures should be applied as an
additional uniform (rectangular) pressure distribution. The corresponding lateral earth pressure
coeffIcient for a uniform vertical surcharge behind the wall is 0.50. Vertical surcharge setback
H:\RP'T\lOO66.ROI
-6-
\0
I '" .
.
.
'"
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
.
I
Basics Etc. Corporation
30-066
October 8, 1993
Schaefer Dixon Associates
A Huntingdon Compon]
behind the wall a horizontal distance greater than the exposed wall height need not be added to
the design pressures.
6.4.3 Backfill
Backfill behind walls below grade should consist of onsite or granular materials as discussed
above. All backfill should be moisture conditioned to approximately optimum moisture content,
and mechanically compacted throughout to at least 90 percent relative compaction. The gradient
adjacent to walls below grade should be sufficient such that water will drain freely away from
the walls and does not pond.
6.4.4 Wall Backdrains
Adequate drainage should be provided behind walls below grade. Wall backdrains should
consist of a system of perforated pipes behind the wall. The perforated pipes, at least 4 inches
in diameter, should be encapsulated in gravel and wrapped in ftlter fabric. Pipe perforations
should be placed downward. Gravelly ftlters should have a volume of at least one-cubic-foot
per lineal foot of pipe. The filter fabric, such as Mirafi 140 or equivalent, should be approved
by SDA. The backdrainage system should outlet to an appropriate area.
6.5 PAVEMENTS
6.5.1 Subgrade
Asphalt concrete pavement (ACP) or Portland cement pavement should be placed upon a
prepared subgrade. Just prior to placement of pavement structural sections, subgrade soils should
be observed by SDA. Where dry, desiccated, or saturated materials are present, sub grade soils
should be removed to expose competent, unyielding bottom. The excavated materials should
be replaced with compacted fill. Placement of compacted fill should be performed in accordance
with recommendations presented in Section 6.1 of this report. Where subgrade soils are judged
to be competent for support of pavement sections, the exposed material should be scarified to
a depth of about 8 inches, moisture conditioned as needed to slightly above optimum, and
compacted to a minimum relative compaction of 90 percent. Subgrade soils below flatwork
should be moisture conditioned to a moisture content of about 150 percent of optimum. This
condition may be achieved by periodically wetting the sub grade a few days in advance of
concrete placement.
6.5.2 Asphalt Concrete Pavement
ACP may be used in driveways and parking spaces. For design of ACP, structural sections
presented in Table 2 are recommended.
H:\JU"T'\3OOlS6.ROl
-7-
~'\
I
Ii.
I.
I
.
.
.
t
t
.
.
.
.
.
.
.
II
II
II
II
<'-
,'0. .
.
,
,
..l
.
Basics Etc. Corporation
30-066
October 8, 1993
Schaefer Dixon Associates
A Huntingdon Compan]
TABLE 2
ASPHALT CONCRETE PAVEMENT STRUCTURAL SECTIONS
Truck Access 7.0 0.35 1.00
Light Vehicle Primary Access 6.0 0.30 0.80
Light Vehicle Secondary Access & 5.0 0.25 0.65
Parking Bays
Base course should consist of crushed aggregate base conforming to Sections 200-2.2 or 200-2.4
of "Standard Specifications for Public Works Construction (1988)," and should be compacted
to at least 95 percent of maximum dry density determined in accordance with ASTM D 1557-78.
Other design and construction criteria for asphalt concrete pavements, such as mix design,
placement, curing, drainage, maintenance, etc. should conform to current specifications of the
City of Temecula or other applicable agencies.
Special consideration should be given to areas were truck traffic will negotiate small radius
turns. Asphaltic concrete in these areas could utilize stiffer emulsions or these areas should be
paved with portland cement concrete.
6.5.3 Concrete Pavement and F1atwork
Concrete pavement may be used in areas where repetitive use or heavy loading conditions are
expected, such as trash enclosure areas. Concrete sections should have a minimum thickness
of 7.0 inches and be reinforced with a minimum of 6 inch by 6 inch, No.6 by No.6 welded
wire mesh placed in the center. The concrete should have a minimum compressive strength of
4000 psi at 28 days.
Exterior flatwork should have a nominal thickness of 4 inches and be provided with sawcuts or
joints at a maximum spacing of 5 feet. To mitigate differential movement across panels, sawcuts
should extend no more than 1/4 of the slab thickness and joints should have a mechanical
connection such as a key or dowels.
1I:\R.Yf'\J0066.ROI
-8-
\1/
. ,.; . ,'"
'"
..
.
~J
,'.. "
..
"
,
Basics Etc. Corporation
30-066
October 8, 1993
Schaefer Dixon Associates
A Huntingdon Compan]
. 6.6 UTILITY TRENCH BACKFILL
.
.
.
.
.
.
.
Backfill to be placed in the "Pipe-Zone" should consist of sandy materials with no particles
greater than 3/8 inch in maximum dimension. The sandy materials should not contain more than
15 percent of particles smaller than a standard sieve No. 40. For purposes of this report, the
"Pipe-Zone" includes the full width of the trench to a horizontal level about 12 inches above the
top of thepipe. On site materials are not expected to be suitable for use as "Pipe-Zone" backfill,
and import of sandy materials will be necessary.
"
Backfill above the "Pipe-Zone" should be free of vegetation, debris, organics, or particles
greater than 3 inches in dimension. On site soils are generally expected to be suitable for use
as backfill materials above the "Pipe-Zone." Trench backfill above the "Pipe-Zone" should be
mechanically compacted to at least 90 percent of maximum dry density determined in accordance
with ASTM D 1557-78. Trench backfill should be placed in lifts appropriate for the compaction
method used, moisture conditioned to 1 to 3 percent above optimum, and compacted in place
to meet the specified degree of compaction.
6.7 CORROSION PROTECTION
Laboratory test results by SDA for soluble sulfate concentrations in the soil samples indicate a
low potential for corrosion to Portland cement. Accordingly, Type II cement should be adequate
for concrete elements in contact with site soils.
.
.
6.8 SITE DRAINAGE
.
Positive surface drainage should be away from structure foundations and tops of slopes. All
drainage should be directed to appropriate discharge areas via nonerodible devices. In addition,
a regular maintenance program should be implemented to keep drainage devices in good working
condition.
6.9 GROUNDWATER CONSIDERATIONS
.. Provided recommendations in SeCtion 6.8 above are implemented, no additional mitigation for
groundwater is deemed necessary.
..
.
'!
.
..
H:\RF'N0066.ROI
-9-
\ "f)
, .i:. .._;, . I' V
~'.
I.
I
1
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
,"!
.
.
Basics Etc. Corporation
30-066
October 8, 1993
Schaefer Dixon Associates
. A Huntingdon Company
7.0 CONSTRUCTION CONSIDERATIONS
7.1 TEMPORARY EXCAVATIONS
Temporary cuts up to about 4 feet are anticipated for construction of retaining walls. Temporary
vertical cuts up to 5 feet in height are considered adequately stable provided surcharge loads are
not placed within 5 feet of the cut. Cuts greater than 5 feet should be sloped as required by
OSHA for soil type 1.
7.2 EXCAVATION CHARACTERISTICS
Materials in cut areas may be excavated using conventional earthmoving equipment. Blasting
is not expected. Some materials encountered during grading may contain rock greater than
8 inches in diameter. These considerations are discussed under Section 6.1.3.
8.0 GEOTECHNICAL CONSTRUCTION SERVICES
Sufficient and timely observation and testing during construction should be performed by SDA
to correlate. the findings of this study with actual subsurface conditions exposed during
construction, and to verify compliance with project specifications.
9.0 CWSURE
The conclusions, recommendations, and opinions presented herein are: 1) based upon an
evaluation and interpretation of the findings of the field and office evaluation; 2) based upon an
interpolation of subsurface conditions between and beyond data points; 3) subject to confmnation
of the actual conditions encountered during construction; and, 4) based upon the assumption that
sufficient observation and testing will be provided by SDA during construction.
If parties other than Schaefer Dixon Associates are engaged to provide construction geotechnical
services, they must be notified that they will be required to asSume complete responsibility for
the geotechnical phase of the project by concurring with the findings and recommendations in
this report or providing alternative recommendations.
Any persons using this report for bidding or construction purposes should perform such
independent investigations as they deem necessary to satisfy themselves as to the surface and
subsurface conditions to be encountered and the procedures to be used in the performance of
work on this subject.
1I:\IU"T\JOO66.R.OI
-10-
\k...
~-
'-
,
III _ ".....""
.~, ~. Co
"... .
.
. ~.
. ..
,
\,;
~
I
1
I
I
I
I
I
I
I
I
I
I
I
1
".:!
, .'
'-'
. i:" ;
:...P'
YBasics Etc. Corporation
30-066
J October 8, 1993
Schaefer Dixon Associates
A Huntingdon Company
REFERENCES
, .
, ,
1.
Schaefer Dixon Associates, Inc. ,"Geotechnical Investigation: A Portion of North
Jefferson Business Park (phase 4) P.M. No. 23561, (Formerly P.M. 19581-1)," dated
June 1, 1988 (P .N. 80-245).
2. "Geotechnical Engineering Investigation and Review of Grading Plan:
Parcel Map 23561," dated September 29, 1988 (p.N. 8R-1208G).
3. "Grading Report: Parcel Map Numbers 23561, 23561-1 and 23561-2,
Temecula Area, Riverside County, California," dated February 8,1990 (p.N. 9R-1208L)
1I:\RP1'\1OO66.ROI
-11-
\4