HomeMy WebLinkAboutParcel Map 6607 Parcel 24 Preliminary Geotechnical ReportMay 2, 2002
American
•
Geotechnical
Protecting Your Future
Mr. & Mrs. Bob Craig �?02?6 S
43571 Butternut DriveOL/T� Ra /91
Temecula, CA 92592 �C
Subject: COMMENTS REGARDING ONGOING CONSTRUCTION
30865 Lolita Road, Temecula, California
Permit #1301-3352
Reference: REVIEW OF FOUNDATION PLANS FOR
TEMECULA RESIDENCE
Prepared by Dale Sessions
Dated September 1, 2000
FINAL REPORT OF TESTING AND OBSERVATION
SERVICES DURING SITE GRADING
- Crown Point/London-Property, Lot 24, -West 'End of
Pescado Drive, Temecula, California
By American Geotechnical (File No. 22350.01)
Dated June 28, 2000
PRELIMINARY GEOTECHNICAL INVESTIGATION
West End of Pescado Drive, Lot 24, Temecula, California
By Vinje & Middleton Engineering, Inc.
Dated February 25, 2000
Dear Mr. Craig:
File No. 22350.01
This correspondence is a brief follow up to some questions recently asked by the City. As indicated in
our as -graded soil report of June 28, 2000, the building plan was prepared about two years ago in
accordance with the recommendations of our office while under the periodic inspection and testing of our
representatives. The site was constructed utilizing materials that are predominantly granular and not
expansive. As such, all bearing capacity and other soil characteristics/recommendations from the earlier
report remain applicable. It is our understanding that utilities to date have not been completely installed
and, as such, backfilling, observation and/or testing have not been conducted. At the time utility trench
excavation and recompaction are conducted, please contact our office for periodic reviews and testing.
Should you have any further questions, please do not hesitate to call.
GWA:kac
wpdai x\20000\22350-01.gwa. kac
22725 Old Canal Road, Yorba Linda, CA 92887 (714) 685-3900 (800) 275-4436 FAX (714) 685-3909
.. .. '.5764 Pacific Center Boulevard, Suite 112; San Diego, CA 92121 (858) 450-4040 FAX (858) 457-0814
0
6 May 2002
City of Temecula
Department of Building and Safety
43200 Business Park Drive
Temecula, California 92589
Subject: Certification of Line and Grade,°30865 Lolita Road, Building Permit'No.
B013352
To whom it may concern:
I hereby certify that the above project meets line and grade depicted by the site grading and
improvement plans.
If you have any questions regarding this matter please do not hesitate to contact me.
Very ly yours, ^ , PpFESslp
LON
Ke' h A. London " 4 4 m
rn
Registered Civil Engineer No. 42489 cc .3/31104
Cc: Bob Craig , CMV. a�P
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M American Geotechnical
Protecting Your Future
FINAL REPORT OF TESTING AND
OBSERVATION SERVICES DURING SITE GRADING
Crown Point / London Property
Lot 24, West End of Pescado Drive
Temecula, California
File No. 22350.01 June 28, 2000
22725 Old Canal Road, Yorba Linda, CA 92887 (714) 685-3900 (800) 275-4436 FAX (714) 685-3909
5764 Pacific Center Boulevard, Suite 112, San Diego, CA 92121 (858) 450-4040 FAX (858) 457-0814
tJune 28, 2000
1
=American Geotechnical
Protecting Your Future
Mr. Keith London
16835 West Bemardo Drive, Suite 215
San Diego, California 92127
File No. 22350.01
Subject: FINAL REPORT OF TESTING AND OBSERVATION SERVICES DURING IT
GRADING
Crown Point / London Property
Lot 24, West End of Pescado Drive
Temecula, California
1 Reference: "Preliminary Geotechnical Investigation, Lot 24 (PM 6607) West End of Pescado Drive,
Temecula, County of Riverside," prepared by Vinje & Middleton Engineering, Inc., dated
February 25, 2000.
1
Dear Mr. London:
Pursuant to your request, American Geotechnical has provided geotechnical consulting services in the form of
observation and testing during grading of the subject property. Our field services were performed primarily during the
period of May 13, 2000 through June 16, 2000.
Based on the results of the testing and observations, it is our opinion that the grading has been completed in general
conformance with the recommendations in the referenced preliminary geotechnical report and the intentions of this
office.
We appreciate the opportunity to be of service. If you should have any questions or concerns, please contact this
office.
1 Sincerely,
AMERICAN GEOTE
' A�,p-kFsSipti
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'P S0. 2498* �• 12.31-03 a
Reviewed By:
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Owed T. Marsh a No. 'S
' Chief Engineer * qs�
G.E. 2387 ar C0
' RKW/PMP/ETM:Iv CfCAIFO�
Distribution: Mr. Keith London - (2) Via Mail Only
Todd M. Page '11414
Senior Geolog
C.E.G. 2083
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\� CALM'
' 22725 Old Canal Road, Yorba Linda, CA 92887 (714) 685-3900 (800) 275-4436 FAX (714) 685-3909
5764 Pacific Center Boulevard, Suite 112, San Diego, CA 92121 (858) 4504040 FAX (858) 457-0814
' File No. 22350.01
June 28, 2000 American Geotechnical
' Page 1
' 1.0 INTRODUCTION
1.1 GENERAL
' This report presents the results of our testing and observation services during site grading of Lot 24 -west end of
Pescado Drive in the Temecula area of Riverside County. The project grading plans were prepared by Mr. Keith
London and are entitled Rough Grading Plan, Parcel Map 6607, Parcel 24, Temecula County of Riverside,
' California. The project soil report is referenced above.
Based on the results of our observations and testing, it is the opinion of this office that the proposed development
is feasible from a geotechnical standpoint provided the recommendations contained herein, and in the preliminary
geotechnical investigation report, are incorporated into the project plans and specifications.
' 1.2 SCOPE OF SERVICES
1
1
The scope of services performed during grading operations at the site primarily included the following:
• Observing the grading operation, including the removal of loose topsoil, alluvial soil and other unsuitable
material, and the keyway and benching operations for site slopes. In addition, the placement of the canyon
subdrain was observed.
• Performing compaction testing of the fill placed during the grading of the site.
• Performing laboratory tests for evaluating the relative compaction and other engineering characteristics of soil
encountered and/or utilized as fill soil.
• Provided consultation services during grading.
• Performing additional geologic and engineering analysis for the proposed project.
• Preparation of this report presenting the results of the testing and observation services.
' File No. 22350.01
June 28, 2000 M American Geotechnical
' Page 2
' 2.0 SITE PREPARATION AND GRADING
2.1 SITE PREPARATION AND REMOVALS
' During the grading operations, a representative from American Geotechnical was on-site to observe the removal
operations and perform compaction testing as recommended in the preliminary geotechnical report. A few
months prior to initiating grading operations, the site was essentially cleared of vegetation. During the current
' phase of grading, topsoil, alluvium, and other unsuitable material was removed to firm natural ground within the
area of proposed site improvements. The limits of this removal extended beyond the limits of proposed
improvements, as delineated on the site grading plan. In one area alluvium was left in place in a landscaped area.
' This area should be considered as unsuitable for improvements unless the alluvium left in place is removed and
replaced as properly compacted fill. This area is delineated on Plate 1. Finally, on the southern portion of the
north -south trending ridge, relatively shallow undocumented fill was placed in a landscaped area to aid in
' vegetation growth. This area should also be considered as unsuitable for improvements unless the undocumented
fill and any other loose material present is removed and replaced as properly compacted fill.
[1
1
1
2.2 OVEREXCAVATION
In areas where structures would straddle a cut/fill transition line these areas were overexcavated to a depth of at
least three feet to provide a fill blanket beneath the building pad. This was primarily achieved in the area of the
proposed residence and by parking area. It is our understanding that this is also planned for the proposed granny
pad area but has not yet been completed. Prior to proceeding with any construction in the granny pad area this
overexcavation would be necessary. Additionally, for other more critical structures (pools, tennis courts, etc.), if
it is determined, during construction, that these structures straddle a cut/fill transition line it is recommended that
similar overexcavation be conducted. For deeper structures such as pools additional input might need to be
provided by the geotechnical consultant. Once final plans for additional improvements become available they
should be forwarded to this office for review and comment.
2.3 FILL PLACEMENT
Following completion of the removals, fill soil derived from on-site materials was then moisture conditioned,
placed and compacted in thin lifts until the design elevations were obtained. In general, the on-site fill material
consisted primarily of silty sands and sands. A few areas on-site were found to have clayey sand material which
was also utilized as fill. The amount of clayey material encountered during the grading is considered insignificant
with respect to expansive soil concerns.
During the grading operation, compaction procedures were observed and in-place density tests were performed to
evaluate the relative compaction of the fill material. The in-place density tests were performed in general
conformance with ASTM D-1556 (sand cone). The results of the in-place density tests and moisture content tests
are summarized on Table 1. The approximate locations of the in-place density tests are shown on Plate 1. In
general, the in-place density test results indicate that the fill soil, where tested, has a relative compaction of a least
90 percent per ASTM D-1557. Any failed areas tested were re -worked and re -tested until they met or exceeded
the 90 percent relative compaction requirement.
Laboratory tests were performed on samples of material used for fill to evaluate moisture -density relationships,
optimum moisture and maximum dry density. The test results of the laboratory testing conducted are summarized
on Table 2.
Table 1 -
COMPACTION TEST SUMMARY
TEST'
NO.
DATE
ELEVATION
((t)
PERCENT
MOISTURE
DRY
DENSITY
ft
`MAXIMUM
DENSITY
RELATIVE
COMPACTION
oho,
SOIL
TYPE*
REIVIARICS
1
5/16/2000
1251.0
7.5
116.0
128.7
90
1
2
5/16/2000
1252.0
7.0
121.1
128.7
94
1
3
5/16/2000
1185.0
11.0
119.3
128.7
93
1
4
5/16/2000
1254.0
7.5
121.7
129.0
94
2
5
5/17/2000
1201.0
9.0
108.3
120.8
90
3
6
5/17/2000
1256.0
9.5
123.3
129.0
96
2
7
5/17/2000
1202.0
6.5
107.2
120.8
93
3
8
5/18/2000
1255.0
7.5
116.7
129.0
90
2
9
5/18/2000
1225.0
6.5
112.4
120.8
93
3
10
5/18/2000
1206.0
9.0
110.3
120.8
91
3
11
5/18/2000
1231.0
8.0
111.0
120.8
92
3
12
5/19/2000
1210.0
7.2
113.8
120.8
94
1
13
5/19/2000
1255.0
8.5
124.2
129.0
96
2
14
5/19/2000
1258.0
11.0
129.4
129.0
100
2
15
5/22/2000
1216.0
8.5
118.1
120.8
98
3
m m r r m m m m m m m m m m m m m
File No. 22350.01
June 28, 2000
Table 1 -
COMPACTION TEST SUMMARY (con't.)
TEST
NO.
DATE'
ELEVATION
(ft)
PERCENT
MOISTURE
DRY
DENSITY
c
MAXIMUM
DENSITY
c � ;"/o
RELATIVE
COMPACTION
SOIL
TYPE*
REMARKS
16
5/22/2000
1225.0
10.5
129.7
129.0
100
2
17
5/22/2000
1263.0
8.5
115.5
128.7
90
1
18
5/23/2000
1255.0
6.6
122.6
128.7
95
1
19
5/23/2000
1222.0
6.5
111.8
128.7
87
1
FAILED
20
5/23/2000
1221.0
6.7
111.0
120.8
92
3
RETEST OF #18
21
5/23/2000
1238.0
8.7
128.3
128.7
100
1
22
5/24/2000
1228.0
7.0
107.2
120.8
89
3
FAILED
23
5/24/2000
1222.0
6.7
113.7
120.8
94
3
RETEST OF # 22
24
5/24/2000
1226.0
8.4
111.6
120.8
92
3
25
5/24/2000
1222.0
6.4
125.3
128.7
97
1
26
5/24/2000
1225.0
7.6
119.4
128.7
93
1
27
5/25/2000
1261.0
8.0
115.6
128.7
90
1
28
5/25/2000
1262.0
9.0
110.7
128.7
86
1
29
5/25/2000
1261.0
9.0
125.6
128.7
98
1
File No. 22350.01
June 28, 2000
Table 1 -
COMPACTION TEST SUMMARY (con't.)
TEST
NO.
DATE
ELEVATION
(ft)
PERCENT
MOISTURE
DRY
DENSITY
c
MAXIMUM
DENSITY
c
RELATIVE
COMPACTION
"/o
SOIL
TYPE*
REMARKS
30
5/25/2000
1262.0
9.2
127.7
128.7
99
1
31.
5/25/2000
1263.0
8.5
129.0
128.7
100
1
32
5/26/2000
1262.0
7.6
114.6
128.7
89
1
33
5/26/2000
1262.0
9.1
120.9
128.7
94
1
34
5/30/2000
1228.0
7.0
115.0
120.8
95
3
35
5/30/2000
1265.0
9.5
117.4
120.8
97
3
36
5/30/2000
1265.0
7.0
120.1
128.7
93
1
37
5/30/2000
1238.0
2.3
102.5
120.8
84
3
FAILED
38
5/31/2000
1265.0
6.7
117.4
128.7
91
1
39
5/31/2000
1228.0
7.5
105.7
120.8
87
3
FAILED
40
6/1/2000
1228.0
6.9
113.2
120.8
94
3
RETEST OF #39
41
6/i/2000
1229.0
5.0
116.8
128.7
91
1
42 '
6/1/2000
1229.0
9.0
119.8
128.7
93
1
43
6/l/2000
1237.0
6.7
116.7
128.7
91
1
RETEST OF #37
File No. 22350.01
June 28, 2000
Table 1 -
COMPACTION TEST SUMMARY (con't.)
`TEST
NO.
DATE
ELEVATION
(ft)
PERCENT
MOISTURE
DRY
DENSITY
c
MAXIMUM
DENSITY
c
RELATIVE
COMPACTION
"/o
SOIL
TYPE*
REMARKS
44
6/2/2000
1231.0
7.0
114.9
120.8
95
3
45
6/2/2000
1232.0
6.0
124.7
128.7
97
3
46
6/2/2000
1233.0
13.3
122.1
128.7
95
1
47
6/2/2000
1233.0
12.2
105.3
120.8
87
3
FAILED
48
6/5/2000
1234.0
9.5
119.7
128.7
93
1
49
6/5/2000
1236.0
7.0
119.3
128.7
93
1
RETEST OF #47
50
6/6/2000
1266.0
7.8
122.6
128.7
95
1
51
6/6/2000
1266.0
6.1
128.1
128.7
99
1
52
6/6/2000
1237.0
6.9
118.2
129.0
92
4
53
6/6/2000
1230.0
7.8
129.5
129.0
100
4
54
6/7/2000
1259.0
7.0
126.9
129.0
98
4
55
6/7/2000
1259.0
6.8
128.5
129.0
99
4
56
6/7/2000
1260.0
11.2
126.5
129.0
98
4
57
6/8/2000
1248.0
11.0
125.9
129.0
98
2
m
File No. 22350.01
June 28, 2000
Table 1 -
COMPACTION TEST SUMMARY (con't.)
m m m m m m
TEST
NO.
DATE
ELEVATION
(ft)
PERCENT
MOISTURE
DRY
DENSITY
c
MAXIMUM
DENSITY
(c
RELATIVE
COMPACTION
SOIL"
TYPE*
REMARKS
58
6/8/2000
1251.0
11.6
127.2
129.0
99
2
59
6/9/2000
1253.0
10.0
126.1
129.0
98
4
60
6/9/2000
1256.0
11.6
122.8
129.0
95
4
61
6/9/2000
1262.0
11.0
118.6
129.0
91
4
62
6/14/2000
1234.0
10.5
124.2
129.0
96
4
63
6/14/2000
1256.0
10.2
123.0
129.0
95
4
64
6/15/2000
1250.0
9.6
115.2
128.7
90
1
65
6/15/2000
1253.0
8.8
116.8
129.0
91
4
66
6/15/2000
1266.0
9.0
119.8
129.0
93
4
67
6/16/2000
1240.0
10.2
121.7
129.0
94
4
* Soil types are presented on Table 2.
m m m m = m m w m m� m m m� m m m
Table 2 -
MAXIMUM DENSITY SUMMARY
SOIL
TYPE
COLOR
CLASSIFICATION
OPTIMUM
MOISTURE
MAXIMUM DRY
DENSITY (LBS/FT-3)
DESCRIPTION
I
RED BROWN
SILTY TO CLAYEY SAND
10.3
128.7
TERRACE SAND
2
DARK BROWN
SL. SILTY SAND
7.0
129.0
NATIVE TOPSOIL
3
TAN/RED BROWN
SILTY SAND
11.4
120.8
NATIVE BLEND
4
REDDISH BROWN
CLAYEY SAND WITH GRAVEL
8.5
129.0
TERRACE SAND
File No. 22350.01
June 28, 2000
Page 3
M American Geotechnical
A canyon subdrain was placed in the north -south trending canyon on the eastern portion of the site. The
approximate location of this canyon subdrain is presented on Plate 1. The canyon subdrain consisted of
approximately six (6) to eight (8) inches of Caltrans Class II permeable material, beneath a four (4) inch SDR 35
perforated pipe which was then covered with additional Caltrans Class II permeable material. The drain was
completed in general conformance with the recommendations presented in the preliminary geotechnical report.
The total length of the drain was approximately 300 feet with the lower approximately 20 feet being solid pipe.
At the time of drain installation it was estimated that the drain pipe had a flow gradient of greater than or equal to
approximately four (4) percent. Finally, the rip -rap at the end of the pipe still needs to be placed to complete the
drain
1
1
File No. 22350.01
June 28, 2000 M American Geotechnical
t Page 4
' 3.0 FOUNDATION RECOMMENDATIONS
3.1 GENERAL
The following foundation recommendations are provided in consideration of the soil conditions encountered
during site grading. The recommendations below should supersede the recommendations previously given in the
preliminary geotechnical report. All other recommendations given in the referenced preliminary geotechnical
' report still apply. Changes or additions which have been made to the original recommendations are presented
below. Once foundation plans become available they should be forwarded to this office for review and comment.
' 3.2 FOUNDATIONS AND SLAB -ON -GRADE FLOORS
Interior slabs should be a minimum of four (4) inches in thickness and reinforced with a minimum of No. 3
' reinforcing bars spaced at a maximum of 16 inches on center each way placed at the mid -height of the slab.
The interior slabs should be underlain by a minimum of two (2) inches of clean sand, underlain by a moisture
' membrane such as visqueen. The visqueen should be a minimum of 10 mil thick and should provide a continuous
vapor barrier sealed at all splices and around pipes. A five (5) inch thick open graded gravel base should be
placed below the visqueen to provide a capillary break. To help protect the visqueen from punctures during
' placement, it is recommended that a filter fabric such as Mirafi 140N be placed between the crushed rock and
visqueen.
Continuous exterior footings should be at least 15 inches wide and 18 inches deep for one and two story
' structures. Interior footings should be at least 15 inches wide and 12 inches deep. Reinforcement for continuous
footings should consist of four No. 4 reinforcing bars, two (2) each at the top and bottom.
' A continuous footing should be installed across any garage openings to a similar depth and with similar
reinforcement as the exterior continuous footings.
fl
3.3 EXTERIOR CONCRETE FLATWORK
All exterior slabs (walkways, patios, pool decking) should be a minimum of four (4) inches in thickness and
reinforced with No. 3 reinforcing bars spaced at a maximum of 16 inches on center each way placed at the mid -
height of the slab. Wherever the flatwork abuts a landscaped area the flatwork should be provided with a
thickened edge which would consist of a minimum eight (8) inch thickened edge reinforced with two No. 3
reinforcing bars, one each at the top and bottom.
Concrete driveways and parking slabs supported on non -expansive subgrade should be a minimum of five (5)
inches in thickness and reinforced with No. 4 reinforcing bars at a maximum of 16 inches on center each way,
placed mid -height in the slab. Any fill placed in the driveway and parking areas has been placed at a minimum
compaction of 90 percent. It is our understanding that the driveway will not be constructed for some time. As
such, prior to placing the concrete for the driveway and/or parking areas the upper 12 inches of the subgrade
should be scarified, moisture conditioned and compacted to a minimum of 95 percent relative compaction.
Wherever, the driveway/parking area abuts a landscaped area the driveway/parking area should be provided with
a thickened edge which would consist of a minimum eight (8) inch thickened edge reinforced with two No. 4
reinforcing bars, one each at the top and bottom. In areas where the driveway will be situated adjacent the top of
a slope the thickened edge should be extended to a depth of 18 inches with three No. 4 reinforcing bars, one each
at the top, middle and bottom.
File No. 22350.01
June 28, 2000 M American Geotechnical
Page 5
3.4 TENNIS COURT
The tennis court concrete slab should be a minimum of five (5) inches in thickness and reinforced with No. 4
reinforcing bars at a maximum spacing of 16 inches on center each way, placed mid -height in the slab section.
Below the tennis court slab a minimum of four (4) inches of open graded gravel should be placed to aid in curing
and to provide a capillary break. Additionally, the slab should either be jointed or otherwise provided with
shrinkage control methods. If jointing of the slab is implemented, joints should occur at a maximum spacing of
12 feet on center each way. Finally, it is recommended that the tennis court slab be moist cured as long as
possible (28 days is typically sufficient) to minimize shrinkage cracking of the slab. Curing methods, other than
moist curing, are available and selection of an alternative curing method may be coordinated with the project
engineer.
The tennis court should be provided with a perimeter thickened edge which would consist of a 12 inch by 12 inch
edge beam. The thickened edge should be reinforced with two No. 4 bars, one each a the top and bottom.
3.5 SITE CONCRETE
Experience and research have shown that concrete with a high water/cementitious materials ratio can experience
problems such as excessive shrinkage cracking, moisture intrusion, and high vapor emissions, among others.
Generally speaking, the higher the water/cementitious materials ratio, the higher the porosity and permeability of
the concrete, and the lower the strength. Concrete designed for minimum compressive strengths on the order of
2,000 to 2,500 psi can oftentimes have excessive levels of mixing water and correspondingly a high
water/cementitious materials ratio.
Consideration should be given to using the lowest possible water/cementitious materials ratio while still
maintaining workability. If necessary, water reducing agents can be used to increase workability. It is
recommended that concrete used for footings and slab areas have a minimum compressive strength of 3,000 psi
with a maximum water/cementitious materials ratio of 0.50. All steel and concrete materials, details, placement
procedures, and curing should be performed strictly in accordance with ACI specifications and guidelines. The
slab design by the structural engineer and/or architect should consider shrinkage of the concrete to limit cracking
to the slab and overlying floor coverings.
3.6 REINFORCEMENT PLACEMENT
Care should be taken when placing foundation and slab reinforcement. Placement details should be in
conformance with ACI specifications. Unless otherwise specified by the structural engineer, continuous footing
reinforcement should be placed in the upper and lower 1/3 portions of the foundation's sections. The bottom
foundations steel should not be closer that three inches to the underlying excavation. Slab reinforcement should
be placed in a positive fashion between the midpoint and upper 1/3 point of the slab section.
"Lifting" slab steel into place following concrete placement is not recommended. If the contractor elects to "lift"
the reinforcement into position following concrete placement, the owner should consider verifying steel
placement by coring of select slab areas. These recommendations apply to both interior and exterior concrete.
3.7 FOOTING SETBACK FOR SLOPES
Any footings near slopes should satisfy a minimum horizontal setback as indicated in the Uniform Building Code,
Chapter 18, Figure 18-I-1. This distance should be measured form the lower leading edge of the footing to the
slope face. For slopes ten (10) feet in height or less, a minimum setback of ten (10) feet is recommended unless
special detailing is implemented.
File No. 22350.01
June 28, 2000
Page 6
M American Geotechnical
3.8 GRADED SLOPES
To minimize potential erosion to graded slopes at the site, it is recommended that these slopes be covered with
erosion control fabric and/or hydro -seeded as soon as possible. Selection of the erosion control fabric can be
coordinated with the geotechnical consultant if necessary.
File No. 22350.01
June 28, 2000 M American Geotechnical
Page 7
4.0 RETAINING WALLS
In order for the soil design parameters presented in the preliminary geotechnical report to be valid, all planned
retaining walls should be designed with appropriate detailing including an adequate backdrain system and a clean,
non -expansive backfill for a width of at least half the height of the retaining wall for level backfill conditions. For
ascending slopes surcharge, the minimum width of the granular backfill should be increased to a value equivalent
to the height of the retaining wall, as a minimum.
All retaining walls should be waterproofed from above the highest point of earth retained to the heel of the
foundation. The architect should provide details for waterproofing including termination details and provisions
for protecting the waterproofing. Each retaining wall should be provided with an appropriate backdrain system
designed by the project civil engineer or architect. It is recommended that the backdrain system extend to the heel
of the foundation, and at least one foot below interior slab elevation (where applicable). Water collected in the
backdrain system should be recovered in a perforated PVC pipe (perforations down) and directed to a suitable
disposal area at two percent gradient unless otherwise specified by the project civil engineer.
Retaining wall backfill should be placed in thin lifts (6 to 8 inches in loose thickness) and compacted by
mechanical means. Care should be taken not to utilize heavy compaction equipment in close proximity to walls to
help reduce the possibility of damage to the wall and an increase in the recommended earth pressures.
File No. 22350.01
June 28, 2000
Page 8
5.0 APPURTENANT STRUCTURE CONSTRUCTION
M American Geotechnical
The same guidelines for slab and footings would also pertain to design and construction of appurtenant structures,
with the exception of exterior flatwork which does not usually necessitate the use of a visqueen moisture barrier.
However, the recommendations for slab thickness and reinforcement, and other recommendations for exterior
flatwork still pertain to help reduce the potential for cracking and separation. The slab(s) should also have proper
jointing incorporated into the design to control cracking. As with interior concrete, all steel and concrete
materials, details, placement procedures and curing should be performed strictly in accordance with ACI
specifications and guidelines.
Special detailing may be necessary to limit unsightly cracking at structural interfaces, such as between
foundations and adjacent slabs. As described, appurtenant structures placed near slope tops could experience
movement over time in response to slope movement. Appurtenant structures should be kept as far away from
slopes as possible. Any footings near slopes should satisfy a minimum horizontal setback as indicated in the
Uniform Building Code, Chapter 18, Figure 18-I-1. This distance should be measured from the lower leading
edge of the footing to the slope face. For slopes ten (10) feet in height or less, a minimum setback of ten (10) feet
is recommended unless special detailing is implemented. This might include structurally tying exterior slabs to
the foundation or providing a thicker, heavily reinforced section. The actual details should be developed by the
project architect and/or structural engineer.
' File No. 22350.01
June 28, 2000
' Page 9
' 6.0 SITE DRAINAGE
M American Geotechnical
Proper surface drainage should be incorporated into the design for the proposed project. Because of potential
problems associated with poor drainage conditions, proper surface drainage should be maintained at all times. As
a minimum, the following standard drainage guidelines are recommended and should be considered by the civil
engineer during final plan preparation:
A. Roof drains should be installed on all structures and tied via a "tight line" to a drain system that empties
to a storm drain, terrace drain, or other suitable disposal area.
B. Surface water should flow away from structures and slopes and be directed to suitable (maintained)
disposal systems such as yard drains, drainage swales, street gutters, etc. Five percent drainage directed away
' from structures is recommended, and two percent minimum is recommended over soil areas. Planter areas
adjacent the foundation are not recommended, unless the plants are self-contained with appropriate drainage
outlets (i.e., drainage outlets tied via a "tight line" to a yard drain system).
' C. No drains should be allowed to empty adjacent foundations or over slopes.
D. PVC Schedule 40 or equivalent is preferred for yard drains. A corrugated plastic yard drain is not
�' recommended.
' File No. 22350.01
June 28, 2000 M American Geotechnical
' Page 10
' 7.0 ADDITIONAL TESTING AND CONSTRUCTION OBSERVATIONS
We recommend that any excavations made during construction be reviewed by the geotechnical consultant. This
' would include excavations for site retaining walls, pools, foundations, slabs, utility trenches or other
improvements. It is also recommended that a member of our staff be present to test any fill being placed on-site.
Additionally, slab subgrade preparation should be observed and tested as recommended by a member of our staff
prior to the placement of forms, reinforcement or concrete.
8.0 LIMITATIONS
t This report has been prepared for the sole use and benefit of our client in accordance with generally accepted
geologic and geotechnical engineering principles and practices. Subsurface conditions, and the accuracy of tests
used to measure such conditions, can vary greatly with time. The intent of the report is to advise our client on
' geotechnical matters involving the proposed development. We are not responsible for any conclusions or
recommendations made by others regarding the site without an opportunity to review such conclusions and
recommendations and concur in writing.
It should be understood that the geotechnical consulting provided and the contents of this report are not perfect.
Any errors or omissions noted by any party reviewing this report, and/or any other geotechnical aspects of the
project, should be reported to this office in a timely fashion. The client is the only party intended by this office to
directly receive this advice. Subsequent use of this report can only be authorized by the client. Any transferring
of information or other directed use by the client should be considered "advice by client."
Conclusions and recommendations presented herein are based upon observation and testing, the evaluation of
technical information gathered, experience, and professional judgment. Other consultants could arrive at different
conclusions and recommendations. Final decisions on matters presented are the responsibility of the client and/or
the governing agencies. No warranties in any respect are made as to the performance of the project.