HomeMy WebLinkAboutMS 14-11; MATHIS LEVANTE SUBDIVISION; LIMITED SITE INVESTIGATION; 2002-07-25EASCOUNTY SOIL- CONSULTATION
AND ENGINEERING, INC.
10925 HARTLEY ROAD, SUITE "I"
SANTEE, CALIFORNIA 92071
(619) 258-7901
Fax 258-7902
Dennis Mathis Construction July 25, 2002
3351 Venado Street Project No. 02-1147J"-
Rancho La Costa, California 92009
Subject: Limited Site Investigation
Four Proçosed Single Family Residences
Lot 230 & 231 Levante Street
APN 223-170-18 & 19 S E P ?2
City of Carlsbad, California
Dear Mr. Mathis:
In accordance with your request, we have performed a limited
investigation of the soil conditions at the subject site. The
investigation was undertaken to provide the soil engineering
criteria for site grading and to recommend an appropriate
foundation system for the proposed residences.
The Site was previously graded as cut and fill pads with a maximum
depth of fill of approximately 12 feet. Underlying the fill soils
was dense sandstone of the Santiago Formation.
It is our opinion that the proposed development is feasible
provided the recommendations herein are implemented during
construction.
Respectfully submitted,
M,
Mamadou Saliou Diallo, P.E
ROE 54071
DENNL5 [THIS CONSTRUCTION PROJECT. 01-1147,;2
INTRODUCTION
This is to present the findings and conclusions of a soils
investigation for four proposed single family residences to be
located on the north side of Levante Street, in the City of
Carlsbad, California.
The objectives of the investigation were to determine the existing
soils conditions and provide recommendations for site development.
In order to accomplish these objectives, eight (8) exploratory
trenches were excavated to a maximum depth of 13.0 feet;
undisturbed and loose bag samples were obtained, and laboratory
tests were performed.
SITE DESCRIPTION AND PROPOSED CONSTRUCTION
The subject site is located on the north side of Levante Street,
in the City of Carlsbad, California. The site was previously
graded as cut and fill pads. Prior to the grading operation, the
site sloped moderately to the west. Vegetation consists of grass.
The proposed development includes the construction of four two-
story, wood-framed, single-family residences to be founded on
continuous footings with a slab-on-grade floor system.
FIELD INVESTIGATION
On March 28, 2002, eight exploratory trenches were excavated to a
maximum depth of 13.0 feet by a Caterpillar 4163 backhoe equipped
with a 24 inch bucket. The approximate locations of the trenches
are shown on the attached Plate No. 1, entitled "Location of
Exploratory Trenches". A continuous log of the soils encountered
was recorded at the time of excavation and is shown on Plates No.
2 through 4 entitled "Summary Sheet".
The soils were visually and texturally classified according to the
filed identification procedures set forth on the at-:ached Plate No. 5 entitled "Uniform Soil Classification Chart.
SURFACE CONDITIONS
The surface soils encountered during the course of our
investigation were fill soils to a maximum depth of twelve (12)
feet. These soils consist of tan clayey sand and silt.r sand, with
a loose to medium dense consistency. The fill soils were underlain
by dense sandstone of the Santiago Formation (Tsa)
2
DENNIL THIS CONSTRUCTION PROJECT 01-1147J2
EXPANSIVE SOILS
An expansion test was performed on a representative sample of the
fill soils to determine volumetric change characteristics with
change in moisture content. An expansion index of 40 indicates a
low potential for expansion.
GROUNDWATER
Groundwater was not encountered during the course of our
investigation. Groundwater is anticipated at a depth greater than
150 feet. We do not expect groundwater to affect the proposed
development.
GEOLOGIC HAZARDS
A review of the available geological literature pertaining to the
site indicates the existence of the Rose Canyon Fault Zone
approximately '10.5 Km to the west. Ground shaking from this fault
or one of the major active faults in the region is the most likely
happening to affect the site. With respect to this hazard, the
site is comparable to others in the general area.
The proposed residential structures should be designed in
accordance with seismic design requirements of the 1997 Uniform
Building Code or the Structural Engineers Association of
California using the following seismic design criteria:
Seismic Zone Factor, Z 0.40 Table 16-I
Soil Profile Type SD Table 16-J Seismic Coefficient, Ca 0.44 Table 16-Q Seismic Coefficient, Cv 0.64. Table 16-R Near-Source Factor, Na 1.0 Table 16-S Near-Source Factor, Nv 1.0 Table 16-T
Seismic Source B Table 16-U
Based on the absence of shallow groundwater, type and consistency
of the underlying soils, it is our opinion that the potential for
liquefaction is 'very low.
DENNIS THIS CONSTRUCTION PROJECT) 01-1147J2
CONCLUSIONS AND RECOMMENDATIONS
The following conclusions and recommendations a
r
e
b
a
s
e
d
u
p
o
n
t
h
e
analysis of the data and information obtai
n
e
d
f
r
o
m
o
u
r
s
o
i
l
investigation. This includes visual inspection; field investigation; laboratory testing and our genera
l
k
n
o
w
l
e
d
g
e
o
f
t
h
e
soils native to the site. The site is suitable f
o
r
t
h
e
p
r
o
p
o
s
e
d
development provided the recommendations set forth
a
r
e
i
m
p
l
e
m
e
n
t
e
d
during construction.
GRADING AND EARTHWORK
Site grading should begin with clearing and gr
u
b
b
i
n
g
,
e
.
g
.
t
h
e
removal of vegetation and deleterious materi
a
l
s
.
I
t
i
s
o
u
r
understanding that the two existing pads will be g
r
a
d
e
d
i
n
t
o
f
o
u
r
individual pads. Due to the transition between
c
u
t
a
n
d
f
i
l
l
o
n
t
h
e
existing pads and the loose consistency in the
u
p
p
e
r
3
f
e
e
t
o
f
t
h
e
existing fill soils, we recommend that the
s
u
b
g
r
a
d
e
s
o
i
l
s
b
e
overexcavated to a minimum depth of three feet
b
e
l
o
w
p
r
o
p
o
s
e
d
p
a
d
grades, moisture conditioned 2 to 4 percent
o
v
e
r
o
p
t
i
m
u
m
a
n
d
compacted to a minimum of 90 percent rela
t
i
v
e
d
e
n
s
i
t
y
.
T
h
e
overexcavation should extend a minimum of 5 feet
b
e
y
o
n
d
p
e
r
i
m
e
t
e
r
footings. The actual depth and extent of re
m
o
v
a
l
s
h
o
u
l
d
b
e
evaluated in the field at the time of ex
c
a
v
a
t
i
o
n
b
y
a
representative of this firm. Grading should be do
n
e
i
n
a
c
c
o
r
d
a
n
c
e
with the attached appendix A.
FOUNDATION AND SLAB
Continuous footings and/or spread footings are
s
u
i
t
a
b
l
e
f
o
r
u
s
e
and should extend a minimum of 18 inches fo
r
t
h
e
t
w
o
s
t
o
r
y
residential dwellings into the compacted fill
s
o
i
l
s
.
C
o
n
t
i
n
u
o
u
s
footings should be 15 inches wide and reinforc
e
d
w
i
t
h
f
o
u
r
#
4
steel bars; two bars placed near the top of the
f
o
o
t
i
n
g
s
a
n
d
t
h
e
other two bars placed near the bottom of the footi
n
g
s
.
Concrete floor slabs should be a minimum 4
i
n
c
h
e
s
t
h
i
c
k
.
Reinforcement should consist of #3 bars placed
a
t
1
6
i
n
c
h
e
s
o
n
center each way. Slab reinforcement should b
e
p
l
a
c
e
d
w
i
t
h
i
n
t
h
e
middle third of the slab by supporting the stee
l
o
n
c
h
a
i
r
s
o
r
concrete blocks dobies1'. The slab should be underlain by 2 inches
of clean sand over a 10-mil visqueen moisture barr
i
e
r
.
T
h
e
e
f
f
e
c
t
of concrete shrinkage will result in cracks
i
n
v
i
r
t
u
a
l
l
y
a
l
l
concrete slabs. To reduce the extent of shrinkag
e
,
t
h
e
c
o
n
c
r
e
t
e
should be placed at a maximum of 4-inch slump.
T
h
e
m
i
n
i
m
u
m
s
t
e
e
l
recommended is not intended to prevent shrinkage
c
r
a
c
k
s
.
4
DENNIS THIS CONSTRUCTION PROJECT 01-114712
c. Where moisture sensitive floor coverings are anticipated over
the slab, the 10-iril plastic moisture barrier should be underlain
by a capillary break at least 4 inches thick, consisting of sand,
gravel or crushed rock not exceeding 3/4 inch in size with no more
than 5 percent passing the #200 sieve.
SOIL BEARING VALUE
An allowable soil bearing value of 1500 pounds per square foot may
be used for the design of continuous and spread footings founded a
minimum of 12 inches. into the compacted fill soils. TIis value may
be increased by 20 percent for each additional foot of width or
depth to a maximum. value of 4500 lb/ft2 as set forth in the 1997 Edition of the Uniform Building Code, Table No. 18-1-A.
LATERAL SOIL PRESSURE
Lateral resistance to horizontal movement may be provided by the
soil passive pressure and the friction of concrete to soil. An
allowable passive pressure of 200 pounds per square foot per foot
of depth may be used. A coefficient of friction of 0.35 is
recommended. The soils passive pressure as well as the bearing
value may be increased by 1/3 for wind and seismic loacing.
RETAINING WALLS
Unrestrained, cantilevered retaining walls with a level backfill
may be designed to resist an active equivalent fluid pressure of
35 pounds per cubic foot, while retaining walls with a 2 to 1
sloping backfill may be designed to resist an active equivalent
fluid pressure of 45 pounds per cubic foot. This pressure is based
on the backfill soils being free draining and non-expansive.
Backfill materials must be approved by the soils engineer prior to
use.
SETTLENT
Settlement of compacted fill soils is normal and should be
anticipated. Because of the minor thickness of the fill soil under
the proposed footings and the light building loads, the settlement
should be within acceptable limits.
5
DENNIS. HIS CONSTRUCTION PROJECT I )1-1147J2
UTILITY TRENCH EXCAVATIONS
Excavations for on-site utility trenches may be made vertica
l
l
y
for shallow depths and must be either shored or sloped at 1H: 1
V
for depths greater than 4 feet, Utilities should be bedded
a
n
d
backfilled with clean sand or approved granular soil to a depth of
at least one foot over the pipe. This backfill should be uniforml
y
watered and compacted to a firm condition for pipe support. The
remainder of the backfill may be on-site soils or non-expansive
imported soils, wh:ch should be placed in thin lifts, moistur
e
conditioned and compacted to at least 90 % relative compaction.
SLOPE SETBACK
Compacted fill soils that occur within 8 feet of the face of
s
l
o
p
e
possess poor lateral stability, even though they have b
e
e
n
certified with a relative compaction of 90 percent or better.
Proposed structures and other improvements that are located wit
h
i
n
8 feet of the face of compacted fill slopes could suff
e
r
differential movement as a result of the poor lateral stability
o
f
these soils. Therefore, foundations and footings for the propose
d
structures or other improvements should be placed at least 8 feet
back from the top of these slopes. Foundations placed closer to
the top of slope than 8 feet should be deepened such that the
bottom of the foundation is at least 8 feet back from the face o
f
the slope.
DRAINAGE
Adequate measures shall be undertaken to properly finish grad
e
t
h
e
site after the structures and other improvements are in plac
e
,
such that the drainage water within the site and adjacent
properties is directed away from the foundations, footings, floor
slabs and the tops of slopes via surface swales and subsurface
drains towards the,natural drainage for this area. Proper surface
and subsurface drainage will be required to minimize the potential
of water seeking the level of the bearing soils under the
foundations, footings and floor slabs, which may otherwise result
in undermining and differential settlement of the structures an
d
other improvements.
DENNIL I THIS CONSTRUCTION PROJECT 01-1147J2
LIMITS OF INVESTIGATION
The recommendations provided in this report pertain onl
y
t
o
t
h
e
site investigated and based upon the assumption that t
h
e
s
o
i
l
conditions do not -deviate from those disclosed in the trenáhes.
I
f
any variations or undesirable conditions are encountere
d
d
u
r
i
n
g
construction, or if the proposed construction will differ
f
r
o
m
that planned at tie present time, East County Soil Consult
a
t
i
o
n
and Engineering, Inc. should be notified so that supple
m
e
n
t
a
l
recommendations can be provided.
Plates No. 1 through 5, Page L-1 and L-2, References and Ap
p
e
n
d
i
x
A are parts of this report.
Respectfully submitted,
E3S'Q4
CID rn LLj 1(fc.c
CN-
ooii 11
Mamadou Saliou Diallo
RCE 54071
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EAST COUNTY SOIL CONSULTATION
& ENGINEERING, INC.
10925 HARTLEY RD.. SUITE I. SANTEE, CA 92071 l/5&Vb,v
(619) 258-7901 Fax (619) 258.7902
-y Z1'z
DENNIS HIS CONSTRUCTION PROJECT A )1-1147J2
PLATE NO. 2
SUMMARY SHEET NO. 1
TRENCH NO. 1
DEPTH SOIL DESCRIPTION Y N
Surface FILL (Qaf)
tan, dry to moist, loose to medium
dense, silty, fine grained sand (SM)
2.0' 107.9 9.6 2.5' medium brown, moist, medium dense,
silty, fine -grained sand(SM)
3.5' tan, moist, medium dense, silty 104.8 7.5 fine grained sand
5.0' reddish brown, moist, medium dense,
silty, fine to medium grained sand
6.0' SANTIAGO FORMATION (Tsa)
tan, moist, dense, fine
grained silty sand (SM)
6.5' bottom of trench
trench backfilled 3/28/02 ------------------------------------------------------------------------
TRENCH NO. 2
DEPTH SOIL DESCRIPTION Y N
Surface FILL (Qaf)
tan, dry to moist, loose to medium
dense, silty, fine grained sand (SM)
1.0' SANTIAGO FORMATION (Tsa)
tan, moist, dense, fine
grained silty sand (SM)
2.0' 110.7 11.5 2.5' bottom of trench
trench backfilled 3/28/02 ------------------------------------------------------------------------
TRENCH NO. 3
DEPTH SOIL DESCRIPTION Y N
Surface FILL (Qaf)
tan, dry to moist, loose to medium
dense, silty, fine grained sand (SM)
2.0' medium brown, moist, medium dense, 103.8 20.8
clayey sand (SC)
4.0' SANTIAGO FORMATION (Tsa)
tan, moist, dense, fine 101.6 5.8 grained silty sand (SM)
5.5' bottom of trench
trench backfilled 3/28/02
DENNIS THIS CONSTRUCTION PROJECT? 91-1147J2
PLATE NO. 3
SUMMARY SHEET NO. 2
TRENCH NO. 4
DEPTH SOIL DESCRIPTION Y M
Surface FILL (Qaf)
tan, dry to moist, loose
silty, fine grained sand (SM)
2.0' tan, moist, medium dense,
silty, fine grained sand (SM)
5.0' reddish brown, moist, medium dense,
clayey sand (SC)
6.0' SANTIAGO FORMATION (Tsa)
tan, moist, dense, fine
grained silty sand (SM)
6.5' bottom of trench
trench backfilled 3/28/02
TRENCH NO. 5
DEPTH SOIL DESCRIPTION Y M
Surface FILL (Qaf)
tan, dry to moist, loose to medium
dense, silty, fine grained sand (SM)
2.01 106.4 12.3 4.0' 102.4 9.6 4.5' SANTIAGO FORMATION (Tsa)
medium brown, moist, medium dense,
clayey sand(SC)
6.0' tan, moist, dense, fine
grained silty sand (SM)
6.5' bottom of trench
trench backfilled 3/23/02
TRENCH NO. 6
DEPTH SOIL DESCRIPTION y M
Surface FILL (Qaf)
tan, dry to moist, loose to medium
dense, silty, fine grained sand (SM)
4.5' SANTIAGO FORMATION (Tsa)
medium brown, moist, medium dense,
clayey sand(SC)
6.0' tan, moist,- dense, fine
grained sL..ty sand (SM)
6.5' bottom of trench
trench backfilled 3/28/02
DENNIS. rHIS CONSTRUCTION PROJECTI' ]-1]47J2
PLATE NO. 4
SUMMARY SHEET NO. 3
TRENCH NO. 7
DEPTH SOIL DESCRIPTION Y
Surface FILL (Qaf)
tan, dry to moist, loose to 2.0', medium
dense 2.01 -5.5', silty, fine grained
sand (SM)
5.5' brown, moist, medium dense,
clayey sani.(SC)
7.01 SANTIAGO FORMATION (Tsa)
tan, dry, dense, fine
grained silty sand (SM)
7.5' bottom of trench
trench backfilled 3/28/02 ------------------------------------------------------------------------
TRENCH NO. 8
DEPTH SOIL DESCRIPTION Y M
Surface FILL (Qaf)
tan, dry to moist, loose to medium
dense, silty, fine grained sand (SM)
4.0' 105.6 16.9 4.5' medium brown, moist, medium dense,
silty, fine grained sand(SM)
5.5' tan, moist, medium dense, silty
fine grained sand
6.0' 102.0 22.5 8.0' reddish brown, moist, medium dense, 99.1 22.1 clayey sand
12.0' SANTIAGO FORMATION (Tsa)
tan, dry, dense, fine
grained silty sand (SM)
13.0' bottom of trench
trench backfilled 3/28/02 -----------------------------------------------------------------------
10
CLASSIFICATION RANGE OF GRAIN SIZES
- U.S. STANDARD GRAIN SIZE IN
SIEVE SIZE MILLIMETERS
BOULDERS Above 12 Inches Above 305
COBBLES 12 Inches To 3 Inches 1 305 To 76.2
GRAVEL 3 Inches to No.4 76.2 to 4.76
Coarse 3 Inches to 'h Inch 76.2 to 19.1
Fine Inch to No.4 19.1 to 4.76
SAND No. 4 to No. 200 4.76 to 0.074 Coarse No. 4 to No. 10 4.76 to 2.00
Medium No. IC- to No. 40 2.00 to 0.420
Fine No. 40 to No. 200 0.420 to 0.074
SILT AND CLAY Below No. 200 1 Below 0.074
GRAIN SIZE CHART
0 to 20 .0 40 20 50 70 00 30 too
UQIJI0 uir (u.).
PLASTICITY CHART
50
S.
=
'I
20
to
0
MAJOR DIVISI S SYMBOL
GW
L RJPTION
WELL GRADED GRAVELS OR GRAVEL- SAND
MIXTURES, LITTLE OR NO FINES
GP GRAVELS
(MORE THAN POORLY GRADED GRAVELS OR GRAVEL-SAND
OF COARSE MIXTURES, LITTLE OR NO FINES
GM FRACTION
>NO. 4 SIEVE SILTY GRAVELS, GRAVEL-SAND-SILT MIXTURES
COARSE SIZE)
GC GRAINED SOILS CLAYEY GRAVELS, GRAVEL-SAND-CLAY MIXTURES
(MORE THAN ½ OF SOIL> sw NO. 200 SIEVE SIZE) WELL GRADED SANDS OR GRAVELLY SANDS,
LITTLE OR NO FINES
SP SANDS
(MORE THAN V2 POORLY GRADED SANDS OR GRAVELLY SANDS,
OF COARSE LITTLE OR NO FINES
SM FRACTION
<NO. 4 SIEVE SILTY SANDS, SILT-SAND MIXTURES
SIZE)
Sc CLAYEY SANDS, SAND-CLAY MIXTURES
rVJL INORGANIC SILTS AND VERY FINE SANDS, ROCK
SILTS & FLOUR, SILTY OR CLAYEY FINE SANDS OR CLAYEY
SILTS WITH SLIGHT PLASTICITY CLAYS CL INORGANIC CLAYS OF LOW TO MEDIUM
LIQUID LIMIT PLASTICITY, GRAVELLY CLAYS, SANDY CLAYS,
<50 SILTY CLAYS, LEAN CLAYS
OL FINE GRAINED
SOILS ORGANIC SILTS AND ORGANIC SILTY CLAYS OF
LOW PLASTICITY (MORE THAN ½ OF SOIL
< MH NO. 200 SIEVE SIZE) INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS SILTS & FINE SANDY OR SILTY SOILS, ELASTIC SILTS
CH CLAYS
L:QUID LIMIT INORGANIC CLAYS OF HIGH PLASTICITY, FAT
50 CLAYS
OH ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY,
ORGANIC SILTY CLAYS, ORGANIC SILTS
HIGHLY ORGANIC SOILS Pt PEAT AND OTHER HIGHLY ORGANIC SOILS
CLASSIFICATION CHART (UNIFIED SOIL CLASSIFICATION SYSTEM)
70. -
EAST COUNTY SOIL CONSULTATION
AND ENGINEERING, INC.
10925 HARTLEY ROAD, SUITE "I"
SANTEE, CALIFORNIA 92071
U.S.C.S. SOIL CLASSIFICATION
DENNIS MATHIS CONSTRUCTION PROJECT
PROJECT NO. 02-1147J2
PLATE NO. 5 7/10/02
DENNIS HIS CONSTRUCTION PROJECT )1-1147J2
PAGE L-1
LABORATORY TEST RESULTS
RESULTS OF EXPANSION INDEX TEST
An expansion test in conformance with UBC 18-2 was performed on a representative sample of on-
site soils to determine volumetric change characteristics with change in moisture content. The
recorded expansion of the sample is presented as follows:
INITIAL SATURATED INITIAL DRY
MOISTURE MOISTURE DENSITY EXPANSION
CONTENT% CONTENT% LB./CU. FT. INDEX LOCATION
13.0 22.1 99.1 T-3 @2.5'
RESULTS OF PARTICLE SIZE ANALYSIS
US Standard
§ie Size!.:
(ASTM_D-422)
PercentPmg
"
100
1/2" - 98
3/8" 100 95
#4 98 90
#8 88 85
#16 80 76
#30 75 70
#60 61 58
#100 44 46
#200 33 40
USCS SM SC
11
DENNIS THIS CONSTRUCTION PROJECT 91-1147J2
PAGE L-2
LABORATORY TEST RESULTS
RESULTS OF MAXIMUM DENSITY TESTS
The maximum dry densities and optimum moisture contents of the fill materials as determined by
ASTM D1557-91, Procedure A which uses 25 blows of a 10 pound slide hammer falling from a
height of 18 inches on each of 5 equal layers in a 4 inch diameter 1/30 cubic foot compaction
cylinder and Procedure C which uses 56 blows of a 10 pound slide hammer falling from a height of
18 inches on each of 5 equal layers in a 6 inch diameter 1/13.3 cubic foot compaction cylinder are
presented as follows:
OPTIMUM
MAXIMUM MOISTURE
DRY DENSITY CONTENT SOIL TYPE! PROCEDURE LB/CU. FT. % DRY WT. LOCATION
1/A TAN BROWN SILTY FINE 119.0 11.7 T-1@2.5' GRAINED SAND
2/A TAN SILTY FINE GRAINED SAND 118.0 11.4 T-3@1.0'
12
DENNIS) HIS CONSTRUCTION PROJECT N 1-1147J2
REFERENCES
1: "1997 Edition, Uniform Building Code, Volume 2, Structural
Engineering and Design Provisions".
"Maps of Known Active Fault Near-Source Zones in California and
Adjacent Portions of Nevada", Page 0-38, used with the 1997
Edition of the Uniform Building Code, Published by International
Conference of Building Officials.
"Geologic Maps of the Northwestern Part of San Diego County,
California. Plate Nc. 2, Geologic Maps of the Encinitas and Rancho
Santa Fe 7.5' Quadrangles", by Slang S. Tan and Michael P.
Kennedy, 1996.
"Geologic Maps of the Northwestern Part of San Diego County,
California. Plate No. 2, Geologic Maps of the Encinitas and Rancho
Santa Fe 7.5' Quadrangles", by Siang S. Tan and Michael P.
Kennedy, 1996.
13
EAST COUNTY SOIL CONSULTATION
AND ENGINEERING, INC.
10925 HARTLEY ROAD, SUITE I
SANTEE, CALIFORNIA 92071
(619) 258-7901
APPENDIX A
RECOMMENDED EARTHWORK SPECIFICATIONS
General Description
The intent of these specifications is to obtain uniformity and adequate strength in filled ground so
that the proposed structures may be safely supported. The procedures include the clearing and
preparation of the land to be filled, processing the fill soils, the spreading, and compaction of the
filled areas to conform with the lines and grades as shown on the approved plans.
The owner shall retain a Civil Engineer qualified in soil mechanics (herein referred to as engineer)
to inspect and test earthwork in accordance with these specifications. The engineer shall advise the
owner and grading contractor immediately if any unsatisfactory conditions are observed to exist
and shall have the authority to reject the compacted filled ground until such time that corrective
measures are taken, necessary to comply with the specifications. It shall be the sole responsibility
of the grading contractor to achieve the specified degree of compaction.
Preparing Areas to be Filled
All brush, vegetation and any biodegradable refuse shall be removed or otherwise
disposed of so as to leave the areas to be filled free of vegetation and debris. Any uncompacted
filled ground or loose compressible natural ground shall be removed unless the report recommends
otherwise. Any buried tanks or other structures shall be removed and the depression backfilled to
the satisfaction of the engineer.
The natural ground which is determined to be satisfactory for the support of the filled
ground shall then be plowed or scarified to a depth of at least 12 inches (12").
After the natural ground has been prepared, it shall then be brought to the proper
moisture content and compacted to not less than 90 percent of maximum dry density in accordance
with ASTM D1557-91.
Where fills are made on slopes greater than 20 percent, horizontal benches shall be cut
into the firm natural ground. The initial bench at the toe of the fill shall be at least 15 feet in width
on firm undisturbed natural ground. The width of all succeeding benches shall be at least 6 feet.
APPENDIX A 2
3. Fill Materials
All material shall be approved by the engineer and shall consist of materials free from vegetable
matter, and other lumps greater than 6 inches in diameter. If, during grading operations, soils are
found which were not encountered and tested in the preliminary investigation, tests on these soils
shall be performed to determine their physical characteristics. Any special treatment recommended
in the preliminary or subsequent soils reports not covered herein shall become an addendum to
these specifications.
4. Placing and Compacting Fill Materials
When the moisture content of the fill material is below that specified, water shall be
added until the moisture content is near optimum to assure uniform mixing and effective
compaction.
When the moisture content of the fill materials is above that specified, the fill material
shall be aerated by blading and scarifying or other satisfactory methods until the moisture content is
near optimum as specified.
After processing, the suitable fill materials shall be placed in layers which, when
compacted, shall not exceed six inches (6"). Each layer shall be spread evenly and shall be
thoroughly mixed during the spreading- insure uniformity of materials and moisture in each layer.
After each layer has been placed, mixed and spread evenly, it shall be thoroughly
compacted to not less than the density set forth in paragraph 2 (c) above. Compaction shall be
accomplished with approval types of compaction equipment. Rolling shall be accomplished while
the fill material is at the specified moisture content. In place density tests shall. be performed in
accordance with ASTM D1556-90.
The surfaces of the fill slopes shall be compacted by means of sheepsfoot rollers or other
suitable equipment. Compacting operations shall be continued until the slopes are stable and until
there is no appreciable amount of loose soil on the slopes.
5. Inspection
Sufficient inspection by our firm or the Soil's Engineer of record and/or his/her representative shall
be maintained during the filling and compacting operations so that he/she can verify that the fill
was constructed in accordance with the accepted specifications.
6. Seasonal Limits
No fill material shall be placed, spread, or rolled if weather conditions increase the moisture
content above permissible limits. When the work is interrupted by rain, fill operations shall not be
resumed until the moisture content and density of fill are as previously specified.
All recommendations presented in the attached report are a part of these specifications.
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