HomeMy WebLinkAboutLANDINGS PUD FOURTH SECOND REPLAT - Filed GR-GEOTECHNICAL REPORT/SOILS REPORT -REPORT
OF A
GEOTECHNICAU INVESTIGATION
FOR
THE JETTY
FORT COLLINS, COLORADO
FAI RFIELD HOMES
LAKEWOOD, COLORADO
PROJECT NO. 8045-89
BY
EMPIRE LABORATORIES, INC.
301 NORTH HOMES STREET
FORT COLLINS, COLORADO 80521
TABLE OF CONTENTS
Table of Contents ..............................................
i
Letter of Transmittal ........ • • .............. ............ ......
1
Report ..........................................................
A-1
Appendix A ..... ..... .....
Test Boring Location Plan ....................................
A-2
A-3
Key to Borings ................................................
A-4
Log of Borings ...............................................
B-1
Appendix B.................................. ..................
B-2
Consolidation Test Data ... • ...
B-3
Hveem Stabilometer Data .....................................
Summary of Test Results ..................... ....... • • • • • • • •
B-4
C-1
Appendix C ........
Empire Laboratories, Inc.
GEOTECHNICAL ENGINEERING 8 MATERIALS TESTING
June 9, 1989
Fairfield Homes
2618 Deframe Circle
Lakewood, Colorado 80228
Attention: Mr. Ken Slyziuk
Gentlemen:
CORPORATE OFFICE
P.O. Box 503 a (303) 464-0359
301 No. Howes • Fort Collins, Colorado 80522
We are pleased to submit our Report of a Geotechnical Investigation pre- pared for the proposed residential development, located at the Northeast
corner of Landings and Boardwalk Drives, Fort Collins, Colorado.
Based upon our findings in the subsurface, it is our opinion the site is
suitable -for the proposed construction, providing the design criteria and
recommendations set forth in this report are met. The accompanying report
presents our findings in the subsurface and our recommendations based upon
these findings.
Very truly yours,
EMPIRE LABORATOR INC.
Alf
Neil R. S lerrod
Senior Engineering Geologist
Reviewed by. -
Chester C. Smith, P.E.
President
t/s
Branch Orykes
C. 9 V,
ERA
1
P.O. Box 16859 P.O. Boa 1135 P.O. Boss 1744
Colorado Springs, CO 80935 Longmont, CO 80502 Greeley, CO 80632
719) 597.2116 (303) 776.3921 (3031 151.0460
Member of Consul)ing Engineers Cow
P.O. Box 5659
Cheyenne. WY 82003
307) 632-9224
REPORT
OF A
GEOTECHNICAL INVESTIGATION
SCOPE
This report presents the results of a geotechnical evaluation
prepared for the proposed residential development located at the
northeast corner of Landings and Boardwalk Drives in south Fort
Collins, Colorado. The investigation included test borings and
laboratory testing of samples obtained from these borings.
The objectives of this study were to (1) evaluate the subsurface
conditions at the site relative to the proposed construction, (2) make
recommendations regarding the design of the substructures, (3)
recommend certain precautions which should be taken because of adverse
soil and/or ground water conditions, and (4) make recommendations
regarding pavement types and thicknesses for the proposed streets to be
constructed at the site.
SITE EXPLORATION
The field exploration, carried out on June 5, 1989, consisted of
drilling, logging, and sampling five (5) test borings. The test borings
were located by Empire Laboratories, Inc. from the existing street
intersections using conventional chaining methods. The locations of the
test borings are shown on the Test Boring Location Plan included in
Appendix A of this report. Boring logs prepared from the field logs are
shown in Appendix A. These logs show soils encountered, location of
sampling, and ground water at the time of the exploration.
The borings were advanced with a four -inch diameter, continuous -
type, power -flight auger drill. During the drilling operations, a
geotechnical engineer from Empire Laboratories, Inc. was present and
made continuous observations of the soils encountered.
SITE LOCATION AND DESCRIPTION
The site is located at the northeast corner of Boardwalk and
Landings Drives in south Fort Collins, Colorado. More particularly, the
site is described as The Jetty, a subdivision situate in the Southwest
1 /4 of Section 36, Township 7 North, Range 69 West of the Sixth P.M.,
City of Fort Collins, Larimer County, Colorado.
The site consists of a vacant tract of land 'vegetated with grass and,
weeds. The property is relatively flat to gently rolling and has positive
drainage to the north-northwest toward the Larimer County Canal, which
forms the north boundary of the site. A narrow ridge, approximately
ten (10) to twenty (20) feet wide and three (3) to five (5) feet high,
parallels Boardwalk and Landings Drives. The canal at the north edge
of the site is approximately ten (10) feet deep.
LABORATORY TESTS AND EVALUATION
Samples obtained from the test borings were subjected to testing in
the laboratory to provide a sound basis for evaluating the physical
properties of the soils encountered. Moisture contents, dry unit
weights, unconfined compressive strengths, water soluble sulfates,
sulfides, pH, resistivity, oxidation-reduction potential, swelling
potentials, and the .Atterberg limits were determined. A summary of the
test results is included in Appendix B. Swell -consolidation and Hveem
stabilometer characteristics were also determined, and curves showing
this data are included in Appendix B.
SOIL AND GROUND WATER CONDITIONS
The soil _ profile at the site consists of strata of materials arranged
in different combinations. In order of increasing depths, they are as
follows:
1) Silty Topsoil: The area tested is overlain by a six (6) inch
layer of silty topsoil. The topsoil has been penetrated by root
a
growth and organic matter and should not be used as a bearing
soil or as a fill and/or backfill material.
2) Silty Clay: This stratum underlies the topsoil and extends to
the sandy gravelly silty clay and/or the bedrock below. The
silty clay is moderately to highly plastic,' is dry to damp and
exhibits moderate bearing characteristics. When wetted, the
clay stratum exhibits high swell potential; and upon loading,
minor consolidation occurs.
3) Sandy Gravelly Silty Clay: This stratum was encountered below
the upper clay in Boring 5 at a depth of three (3) feet below
the surface and extends to greater depths. The silty clay is
plastic, contains varying amounts of sand and/or gravel and
exhibits moderate bearing characteristics in its dry natural
condition.
4) Claystone-Siltstone Bedrock: The bedrock was encountered in
all borings at depths of one and one-half (1-1/2) to seven and
one-half (7-1 /2) feet below the surface and extends to greater
depths. The upper one and one-half (1 -1/2) to two and
one-half (2-1 /2) feet of the bedrock is highly weathered;
however, the underlying claystone interbedded with siltstone is
firm and exhibits high bearing characteristics. When wetted,
the claystone and Siltstone bedrock exhibits high swell
potential.
5) Ground Water: Three days after drilling, no free ground water
was encountered at the site to the depths explored. Water
levels in this area are subject to change due to seasonal
variations and irrigation demands on and/or adjacent to the
site. In addition, it is our opinion that surface water may
percolate through the upper subsoils and become trapped on the
relatively impervious bedrock, forming a perched ground water
condition.
3-
RECOMMENDATIONS AND DISCUSSION
It is our understanding that single-family residences are to be
constructed at the site. The residences will be served by a local
residenti a street.
Site Grading, Excavation and Utilities
Specifications pertaining to site grading are included below and in
Appendix C of this report. It is recommended that the upper six (6) '
inches of topsoil sbelow building, filled and paved areas be stripped and
stockpiled for reuse in planted areas. The upper six (6) inches of the
subgrade below building, paved and filled areas should be scarified and
recompacted two percent (2%) wet of optimum moisture to at least
ninety-five percent (95%) of Standard Proctor Density ASTM D 698-78.
See Appendix C.) Fill should consist of the on -site soils oe imported -
granular material approved by the geotechnical engineer. Fill should be
placed in uniform six (6) to eight (8) inch lifts and mechanically
compacted two percent (2%) wet of optimum moisture to at least
ninety =five percent (9.5%) of Standard Proctor Density ASTM D 698-18.
For stability, cut and fill slopes should be designed on grades no
steeper than 3:1.
Bedrock encountered at the site may be used as fill material in
selected areas. Heavy-duty construction equipment equivalent to a D-8
tractor and/or track mounted excavator having a gross weight of ninety
thousand (90,000) pounds may be needed to excavate the firm bedrock,
and bedrock used as fill should be broken into pieces less than six (6)
inches in diameter. Proper placement of the bedrock as fill may be
difficult, and a' disc or other mixing equipment may be needed to obtain
uniform moisture and proper compaction. The bedrock should be used in
open and planted areas or in the lower portion. of fill below paved areas.
In computing earthwork quantities, an estimated shrinkage factor
of eighteen percent (18%) to twenty-three percent (23%) may be used for
the on -site clays compacted to the above -recommended density.
All excavations should be dug on safe and stable slopes. It is
suggested that excavated soil slopes be on minimum grades of 1-1 /2:1 or.
4-
flatter, Firm bedrock may be excavated on near -vertical slopes. The
slope of the sides of the excavations should comply with local codes or_:
OSHA regulations. The side slopes of the excavation should be
maintained under safe conditions until completion of backfilling. In
addition, heavy construction equipment should be kept a safe distance
from the edge of the excavation.
Where utilities are excavated below ground water, dewatering will be
needed during placement of pipe and backfilling for proper construction.
All piping should be adequately bedded for proper load distribution.
Backfill placed in utility trenches in open and planted areas should be
compacted in uniform lifts at optimum moisture to at least ninety percent
90%) of Standard Proctor Density ASTM D 698-78 the full depth of the
trench. The upper four (4) feet of backfill placed in utility trenches
under roadways and paved areas should be compacted at or near optimum
moisture to at least ninety-five percent (95%) of Standard Proctor
Density ASTM D 698-78, and the lower portion of these trenches should
be compacted to at least ninety percent (90%) of Standard Proctor
Density ASTM D 698-78. Addition of moisture to and/or drying of the
subsoils may be needed for proper compaction. Proper placement of the
bedrock as backfill may be difficult.
Stripping, grubbing, subgrade preparation, and fill and backfill
placement should be accomplished under continuous observation of the
geotechnical engineer. Field density tests should be taken daily in the
compacted subgrade, fill, and backfill under the. direction of the
geotechnical engineer.
Laboratory resistivity tests, pH, oxidation-reduction and sulfide
tests performed in the laboratory indicate that the subsoils at the site
are slightly corrosive, and protection of metal utility pipe, in our
opinion, should be considered.
Foundations
In view of the loads transmitted by the proposed residential
construction and the soil conditions encountered at the site, it is
recommended that the structure be supported by a drilled -pier
MMI
foundation system. Using this type of foundation system, the structure
is supported by piers drilled into the bedrock stratum and structural
grade beams spanning the piers. Piers should be straight -shaft and
should be drilled within plumb tolerances of one and one-half percent
1-1 /2%) relative to the length of the pier. The piers are supported by
the bedrock stratum partially through end bearing and partially through
skin friction. It is recommended that all piers have minimum ten (10)
foot lengths and that they be drilled a minimum of three, (3) feet into
the firm bedrock stratum. Piers founded at the above level may be
designed for a maximum allowable end bearing pressure of fifteen
thousand (15,000) pounds per square foot. It is estimated that a skin
friction of one thousand five hundred (1500) pounds per square foot will
be developed for that portion of the pier embedded three (3) feet into
the firm bedrock stratum. To counteract swelling pressures which will
develop if the subsoils become wetted, all piers should be designed for a
minimum dead load of seven thousand five hundred (7500) pounds per
square foot. Where this minimum dead load requirement cannot be
satisfied, it is recommended that skin friction from additional embedment
into the firm bedrock be used to resist uplift. To help provide the
required skin friction, the sides of the pier drilled into the bedrock
stratum should be. roughened. All piers should be reinforced their full
length to resist tensile stresses created by swelling pressures acting on
the pier. It is recommended that all grade beams have a minimum four
4) inch void between the bottom of the beam and the soil below. The
predicted settlement under the above maximum loading should be
negligible. Drilled piers should be designed to resist all induced lateral
forces. It is recommended all piers should have minimum ten (10) inch
diameters.
it is strongly recommended that: the geotechnical engineer be
present during the drilling operations to (1) identify the firm bedrock
stratum, (2) assure that proper penetration is obtained into the sound
bedrock stratum, (3) ascertain that all drill holes are thoroughly
roughened, cleaned and dewatered prior to placement of any foundation
concrete, (4) check all drill holes to assure that they are plumb and of
4-
the proper diameter, and (5) ensure proper placement of concrete and
reinforcement.
Basements, Dewatering Systems and Slabs on Grade
Since no free ground water was encountered at the site to the
depths explored, it is our opinion the proposed basement construction is
feasible. However, since the potential for a perched water table- to
develop on top of the bedrock exists at the site, it is recommended that
all structures founded in or within three (3) feet of the bedrock stratum
be provided with a complete dewatering system. Basements should be
excavated on safe and stable slopes as discussed in the "Site Grading,
Excavation and Utilities" section of this report.
The dewatering system should contain a four (4) inch diameter
perforated pipe, underslab gravel, a sump and pump, and/or other
suitable drain outlet. The perforated pipe should be placed around the
entire perimeter of the lower basement area or any portions of the
structure placed in or within three (3) feet of the bedrock stratum. All
piping in the perimeter trench should be surrounded by clean, graded
gravel' from three -fourths (3/4) inch to the #4 sieve in accordance with
ASTM C 33-78, Size No. 67. The gravel should extend from at least
three (3) inches below the. bottom of the pipe to a minimum of two (2)
feet above the bedrock above the pipe, the full width of the trench. To
minimize the cost of gravel backfil.l, it is suggested that the excavation
be limited to the area necessary for construction; however, the trench
should be a minimum of twelve (12) to eighteen (18) inches wide. The
top of the gravel backfill adjacent to foundation walls should be covered
with an untreated building paper to help minimize clogging of the medium
with earth backfill. To minimize the potential for surface water to enter
the system, it is recommended that a clay backfill be placed over the
system and compacted at or near optimum moisture to at least ninety
percent (90%) of Standard Proctor. Density ASTM D 698-78. (See
Appendix C.) We recommend that the drainage pipe be placed at least
one (1) foot below finished slab and have a minimum grade of one -eighth
1 /8) inch per foot. All lower level slabs surrounded by perimeter
7-
drains should be underlain by a minimum of eight (8) inches of clean,
graded gravel or crushed rock devoid of fines. The drainage system
should empty into a sewer underdrain or storm drain adequately sized to
accept the anticipated flows at the site, or the water from the dr an
should empty into a sump provided in the lower basement area. The
sump should be a minimum of eighteen (18) inches in diameter and three
3) feet deep. A minimum of one (1) foot of clean, graded gravel
meeting the above specifications should be placed adjacent to the bottom
and sides of the sump. The sump should be provided with a pump
designed to discharge all flow to the sump. Water from the sump should
be pumped into an adequate storm drain or sewer underdrain.
Due to the swelling pressures exerted by the materials at subgrade,
it is our opinion that the only pi)sitive solution for construction of
the sla b where movement will not occur is a structural floor with a void
beneath it. However, the cost of this ty pe of system may be prohibitive.
It is our opinion that, with certain precautions and knowing that some` -
risk is involved, a floating floor slab may be a reasonable alternative.
If -the owner is willing to assume the risk of future slab movement and.
related structural damage, the following recommendations may reduce slab
movement and its adverse effects.
Subgrade below slabs on grade at the upper level should be prepared
in accordance with the recommendations .discussed in the "Site Grading,
Excavation and Utilities" section of this report. If the subgrade below
slabs on grade is allowed to cfry below the required moisture, the
subgrade should be rescarified and recompacted to two percent (2%) wet
of optimum moisture to the required density just prior to placement of
underslab gravel and concrete. Slabs on grade at the upper level
should be underlain by a minimum, of four (4) inches of clean, graded
gravel or crushed rock devoid of fines. Slabs surrounded by perimeter
drains should be underlain by a minimum of eight. (8) inches of clean,
graded gravel or crushed rock devoid of fines. Garage slabs should be.
reinforced with wire mesh running through the control joints. Slabs on:
grade should be designed and constructed structurally independent of
bearing members.
Ma
To minimize and control shrinkage cracks which may develop in slabs
on grade, we suggest that control joints be placed every fifteen (15) to
twenty (20) feet and that the total area contained within these joints
be no greater than four hundred (400) square feet. In addition, if
building construction is done during winter months, it is recommended.
that slabs on grade not be placed on frozen ground and that they be
protected from freezing temperatures until they are properly cured.
We further recommend that nonbearing partitions placed on floor
slabs be provided with a slip joint (either top or bottom). Slip joints
reduce pressure applied by heaving floor slabs and thus minimize damage
to the portion of the structure above. It is emphasized that if the
subsoils are kept dry, movement of slabs on grade should be minimal.
However, if moisture is permitted to reach the subsoils •below the slabs.,
heaving will probably occur.
Pavement
It is our opinion that flexible pavement is suitable for the proposed
street construction at the site. A flexible pavement alternate should
consist of asphalt concrete underlain by crushed aggregate base course
and subbase or asphalt concrete underlain by plant mix bituminous base
course. Using the City of Fort Collins "Design Criteria and Standards
for Streets". dated July 1986, a serviceability index of 2, a regional
factor of 1, an. "R" value of 5, a twenty (20) year design life, eighteen
18) kip equivalent daily load applications of 5 for the majority of the
street area and 10 for the entrance portion of the street area, and
weighted structural numbers of 2.35 and 2.65, respectively, the
following minimum pavement thicknesses are recommended:
Maiority of Street
Asphalt Concrete 3"
Crushed Aggregate Base Course 4"
Select Subbase 6"
Total Pavement Thickness 13" .
9-
To minimize and control shrinkage cracks which may develop in slabs
on grade, we suggest that control joints be placed every fifteen (15) to
twenty (20) feet and that. the total area contained within these joints
be no greater than four hundred (400) square feet. In addition, if
building construction is done during winter months, it is recommended
that slabs on grade not be placed on frozen ground and that they be
protected from freezing temperatures until they are properly cured.
We further recommend that nonbearing partitions placed on floor
slabs be provided with a slip joint (either top or bottom). Slip joints
reduce pressure applied by heaving floor slabs and thus minimize damage
to the portion of the structure above. It is emphasized that if the
subsoils are kept dry, movement of slabs on grade should be minimal.
However, if moisture is permitted to reach the subsoils below the slabs,
heaving will probably occur.
Pavement
It is our opinion that flexible pavement is suitable for the proposed
street construction at the site.. A flexible pavement alternate should
consist of. asphalt concrete underlain by crushed aggregate base course
and subbase or asphalt concrete underlain by plant mix bituminous base
course. Using the City of Fort Collins "Design Criteria and Standards
for Streets" dated July 1986, a serviceability index of 2, a regional
factor of 1 , an "R" value of 5, a twenty (20) year design life, eighteen
18) kip equivalent daily load applications of 5 for the majority of the
street area and 10 for the entrance portion of the street area, and
weighted structural numbers of 2.35 and 2.65, respectively, the
following minimum pavement thicknesses are recommended:
Maioritv of Street
Asphalt Concrete 3"
Crushed Aggregate Base Course 4"
Select Subbase 6"
Total Pavement Thickness 13"
9-
Asphalt Concrete 2"
Plant Mix Bituminous Base Course 41 '
Total Pavement Thickness 6J"
Entrance Portion of Street ,
Asphalt Concrete 3"
Crushed Aggregate Base Course 4"
Select Subbase 9"
Total Pavement Thickness 16"
Asphalt Concrete 2"
Plant Mix Bituminous Base Course 5"
Total Pavement Thickness 7"
The select subbase should meet City. of Fort Collins Class 1 specifications,
and the crushed aggregate base course should meet City of Fort Collins
Class 5 or 6 specifications. The subgrade below the proposed asphalt
pavement should be prepared in accordance with the recommendations
discussed in the "Site Grading, Excavation and Utilities" section of this
report. It is extremely important that the subgrade be at or slightly
wet of optimum moisture just prior to placement of the pavement to
minimize swell potential of the clay soil. Due to the plastic nature of the
clay soils at the site, consideration should - be given to reducing the
plasticity and swell potential of the soil by stabilizing the subgrade with
lime, fly ash or kiln dust. This will reduce the potential for swelling of
the subgrade and may increase the life of the pavement structure. Use
of the stabilizing material may also increase the "R" value characteristics
of the subgrade allowing for reduction in the pavement section.
Additional laboratory tests will be required to determine the "R" value
characteristics if stabilization is utilized. Finished subgrade below
pavement sections should be placed a minimum of three (3) feet above
the bedrock. stratum. Where bedrock is encountered within three (3)
feet of street subgrade, it is recommended that subdrains be constructed'
to intercept potential perched water. ` The drainage system should empty
10-
into a storm drain, a sewer underdrain, the existing irrigation ditch or
be disposed of by other suitable means.
It is recommended that the asphalt concrete and/or plant mix
bituminous base course be placed in two (2) to three (3) inch lifts. All
plant mix bituminous base course and asphalt concrete shall meet City of
Fort Collins specifications and should be placed in accordance with these
specifications. All subbase material shall have an "R" value between 50
and 69, the crushed aggregate base course shall have an "R" value
between 70 and 77, the plant mix bituminous base course shall have an Rt
value of 90 or greater, and the asphalt concrete shall have an Rt value of
95 or greater. The "R" value of the pavement materials used should be
verified by laboratory tests. Field density tests should be taken in the
aggregate base course, bituminous base course, and asphalt concrete
under the direction of the geotechnical engineer. .
Rigid Pavement
A feasible pavement alternate at the site would be rigid pavement.
Using the eighteen (18) kip equivalent daily load application described
above, a modulus of subgrade reaction of one hundred (100) pounds per
square inch per inch based on an "R" value of 5, a design life of twenty
20) .years, and concrete designed with a modulus of rupture of six
hundred (600) pounds per square inch, the following minimum pavement
thickness recommended:
All Streets within Subdivision
Nonreinforced Concrete - 5"
Subgrade below proposed streets should be prepared in accordance with
the recommendations discussed above and in the "Site Grading,
Excavation and Utilities" section of this report. Concrete pavement
should be placed directly on the subgrade that has been uniformly and
properly prepared in accordance with the above recommendations. All
concrete used in the paving shall meet ASTM specifications, and all
aggregate shall conform to ASTM C-33 specifications. The concrete
11-
should be designed with a minimum modulus of rupture of six hundred
600) pounds per square inch in twenty-eight (28) days. it is
recommended that laboratory mix designs be done to determine the
proper proportions of aggregates, cement, and water necessary -to meet
these requirements. It is essential that the concrete have a low
water -cement ratio, an adequate cement factor, and sufficient quantities
of entrained air. Joints should be carefully designed and constructed in
accordance with the City of Fort Collins "Design Criteria and Standards
for Streets" to ensure good performance of the pavement. It is
recommended that all concrete pavement be placed in accordance with
City of Fort Collins specifications. If paving is done during cold
weather, acceptable cold weather procedures as 'outlined in the City
specifications should be utilized. The concrete pavement should be
properly cured and protected in accordance with the above
specifications. Concrete injured by frost should be' removed and
replaced. It is recommended that the pavement not be opened to traffic
until a flexural strength of four hundred (400) pounds per square inch is
obtained or a minimum of fourteen (14) days after the concrete has been
placed.
GENERAL RECOMMENDATIONS
1) Laboratory test results indicate that water soluble sulfates in
the soil are negligible, and a Type 1-11 cement may be used in
concrete exposed to subsoils. Slabs on grade subjected to
de-icing chemicals should be composed of a more durable
concrete with low water -cement ratios and higher air contents.
2) Finished grade should be sloped away from the structures on all
sides to give positive drainage. Ten percent (10%) for the first
ten (10) feet away from the structures is the suggested slope.
3) Backfill around the outside perimeter of the structures should
be mechanically compacted at optimum moisture to at least ninety
percent (90%) of Standard Proctor Density ASTM D 698-78.
12-
See Appendix C.) Puddling should not be permitted as a
method of compaction.
4) Gutters 'and downspouts should be designed to carry roof
runoff water well beyond the backfill area.
5) Underground sprinkling systems should be designed such that
piping is placed a minimum of five (5) feet outside the backfill
of the structures. Heads should be designed so that irrigation
water. is not sprayed onto the foundation walls. These
recommendations should be taken into account in the landscape
planning.
6) Plumb,ilg under slabs should be eliminated wherever possible
since plumbing failures are quite frequently the source of free
water which may cause slab heave.
7) Pier -sizes should be proportioned . to equalize the unit loads
applied to the soil and thus minimize differential settlements.
8) It is recommended that compaction requirements specified herein
be verified in the .field with density tests performed under the
direction of the geotechnical engineer.
9) It is recommended that a registered professional engineer design
the substructures and that he take into account the findings
and recommendations of this report.
G MERAL COMMENTS
This report has been prepared to aid in the evaluation of the
property and to assist the architect and/or engineer in the design of
this project. In the event that any changes in the design of the
structures or their locations are planned, the conclusions and
recommendations contained in this report will not be considered valid
13-
unless said changes are reviewed and conclusions of this report modified
or approved in writing by Empire -Laboratories, Inc., the geotechnical
engineer of record.
Every effort was made to provide comprehensive site coverage
through careful locations of the test borings, while keeping the site
investigation economically viable. Variations in soil and ground water
cond.itions between test borings may be encountered during
construction. In order to permit correlation between the reported
subsurface conditions and the actual conditions encountered during
construction and to aid in carrying out the plans and specifications as
originally contemplated, it is recommended that Empire Laboratories,
Inc. be retained to perform continuous construction review during the
excavation and foundation phases of the work. Empire Laboratories,
Inc. assumes no responsibility for compliance with the recommendations
included in this report unless they have been retained to perform
adequate on -site construction review during the course of construction.
14-
APPENDIX A.
PEST BORING LOCATION PLAN
5•r! GoR•t 2
LLA®
0
0
n :'ti•
A-?
KEY TO BORING LOGS
TOPSOIL GRAVEL
FILL SAND & GRAVEL
J-*
SILT e i A SILTY SAND & GRAVEL
i71 CLAYEY SILT ono COBBLES
DSANDY SILT SAND, GRAVEL & COBBLES
CLAY WEATHERED BEDROCK
SILTY CLAY SILTSTONE BEDROCK
SANDY CLAY CLAYSTONE BEDROCK
SAND SANDSTONEBEDROCK
SILTY SAND LIMESTONE
CLAYEY SAND GRANITE
SANDY SILTY CLAY
SHELBY TUBE SAMPLE
STANDARD PENETRATION DRIVE SAMPLER
WATER TABLE 3 DAYS AFTER DRILLING
C
T
HOLE CAVED
5/12 Indicates that 5 blows of a 140 pound hammer falling 30 inches was required to penetrate 12 inches.
A-3
LOG OF 901 NG4
95
90
85
75 --
10111 southwest corner of intersection., elevation= 100.0'.
A-4
EMPIRE LABORATORIES, INC.
Q
LOG Of BORINGS
95
ER
1
m
75
8
A-5
EMPIRE LABORATORIES, INC.
APPENDIX B.
640
60
560
20
SWELL - CONSOLIDATION TEST PRE. 8045
25,20111MOISTURE:
MEN 110 INII
e m m
0.1 0.25 0.5 1.0 5 10
APPLIED PRESSURE — TSF
8 .'0
J
J
W 4.'0
ifj
X
0.0
WRTER ADDED
16 .0
0.1 0.25 0.5 1.0 5
APPLIED PRESSURE - TSF
10
F'IFIP.E LABORATORIES INC
B-2
RESISTANCE R-VALUE AND EXPANSION PRESSURE
OF COMPACTO SOIL
ASTM — D 2844
CL I EllT: FA I RF I ELD HOMES
PROJECT: THE JETTY — BOARDWALK & LANDINGS DRIVE
LOCATI011 OF SAMPLE: COMPOSITE SAMPLE BORING 1-10. 5 @ 0.5' — 4.0'
SAMPLE DATA
TEST SPECIMEN 1 2 3
COMPACTION PRESSURE PSI 0 0 0
DENSITY - PCF 91.8 98.0 102.2
MOISTURE - 28.7 25.1 22.8
EXPANSION PRESSURE PSI 0.00 0.00 0.00
HORIZONTAL PRESSURE @ 160 Psi 154 151 148
SAMPLE HEIGHT - in. 2.48 2.50 2.50
EXUDATION PRESSURE PSI 139 239 438
UNCORRECTED R=VALUE 2.4 4.2 5.8
CORRECTED R-VALUE 2.4 4.2 5.8
R-VALUE AT 300 PSI EXUDATION PRESSURE = 5.1
100
80
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EXUDATION PRESSURE — psi
ElIFIRE LABORATORIES INC
B-3
700 800
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SUMMARY OF TEST RESULTS
Boring Depth % Oxidation -Reduction Resistivity
Flo. (ft) Moi.sture Potential W ohm -cm Sulfide pH
4 0.5-4.0 33.8 .261 1200 trace 7.8
B-6
APPENDIX C.
APPENDIX C.
Suggested Minimum Specifications for Placement of Compacted
Earth Fill and/or Backfills
GENERAL
The geotechnical engineer shall be the owner's, architect's,
engineer's or contractor's representative to observe placement of
compacted fill and/or backfill on the project. The geotechnical engineer
or his representative shall approve all earth materials prior to their use,
the method of placement and the degree of compaction.
MATERIALS -
Soils used for all compacted fill and backfill shall be approved by
the geotechnical engineer or his representative- prior to their use. Fill
material shall be free from organic matter, frozen material and other
unsuitable substance and shall not contain rocks or lumps having a
diameter greater than six (6) inches.
SUBGRADE PREPARATION
All topsoil, vegetation, trees, brush, timber, debris, rubbish and all
other unsuitable material shall be removed to a depth satisfactory to the
geotechnical engineer or his representative. The material shall be
disposed of by suitable means prior to beginning preparation of the
subgrade. The subgrade shall be scarified a minimum depth of six (6)
Inches, moisture conditioned as necessary and compacted In a suitable
manner prior to placement of fHl material. Fill shall not be placed until
approval by the geotechnical engineer or his representative; and in no
case, shall fill material be placed on frozen or unstable ground.
Subgrade which is not stable may require the use of imported granular
material, geotextiles or other methods for stabilization as approved by .the
geotechnical engineer.
FILL PLACEMENT
Fill material shall not be placed during unfavorable weather
conditions. Material
geotechnical engineer
proposed for use as fill shall be
or his representative prior to use.
approved by the
Proposed import
material shall be approved by the geotechnical
Fill
engineer or his
material shall berepresentativepriortohaulingtotheprojectsite.
C-2
uniformly mixed such as to preclude the formation of lenses of material
differing from the surrounding material. All clods shall be broken .into
small pieces. The contractor shall construct the fill in approximately
horizontal lifts extending the entire length of the fill. The thickness of
the layers before compaction shall not be greater than eight (8) inches.
Fill being placed on slopes or hillsides shall be benched into the existing
slope. A minimum two (2) foot horizontal bench shall be cut into the
existing excavated slope for each four (4) feet vertical of fill, or each lift
should be benched slightly into the existing grade.
MOISTURE CONTROL
Prior to and during compaction operations, the fill material being
placed shall be maintained within the range of optimum moisture specified.
A general recommendation is to maintain the fill material within two--
percent (2%) plus or minus of optimum moisture so that proper compaction
to the specified density may be obtained with a minimal effort. In
building pad and paved areas, material exhibiting swelling potential shall
be maintained between optimum moisture and two percent (2%) wet of
optimum moisture content. The moisture content of the fill material shall
be maintained uniform throughout the fill. The contractor may be
required to add necessary moisture to the fill material and to uniformly
mix the water with the fill material if, in the opinion of the geotechnical
engineer, it is not possible to obtain uniform moisture content by adding
water on the fill surface. If,. in the opinion of the geotechnical engineer, .
the material proposed for use in the compacted fill is too wet to permit
adequate compaction, it shall be dried in an acceptable manner prior to
placement and compaction. Uniform mixing may require discing, blading
or other methods approved by the geotechnical engineer or his
representative.
Adjustments of moisture content shall be made on the basis of
determinations of moisture content by field tests as construction
progresses.
COMPACTION
The contractor shall furnish and operate the necessary types and
kinds of equipment to perform the operations required to obtain the
specified compaction. This equipment may include approved tamping
rollers, rubber. tired rollers, smooth wheeled rollers and vibratory
rollers. If a sKeepsfoot roller is used, it shall be provided with cleaner
bars so attached as to prevent the accumulation of. material between the
tamper feet. Fill areas which are not accessible to full-sized construction
equipment shall be placed in maximum four (4) inch lifts and compacted,
with power tampers to the specified density.
C-3
Compaction should meet the minimum percentages of maximum density
as set forth in the project specifications or the recommendations .of the
report. The contract specifications supercede the recommendations. given
in this report.
MOISTURE DENSITY RELATIONSHIP DETERMINATION
Samples of representative fill materials to be placed shall be
furnished by the contractor to the geotechnical engineer for determination
of maximum density and optimum moisture or relative density. Sufficient
laboratory moisture density or relative density curves will be made to
determine the optimum moisture content and -maximum density for the
various soils placed as . fill. Tests for this determination will. be made
using the appropriate method conforming to the requirements of ASTM D
698 (Standard Proctor) ; --ASTM- D-1557 (Modified Proctor)- -or--ASTM 0-4253, -
D 4254 (Relative Density). The materials used for fill shall be classified
In accordance with ASTM D 2487 in order to permit correlation between
the moisture -density relationship data and the material being placed and
compacted.- Copies of the results of these tests; will be furnished to the
client and others as directed by the client. These test results shall be
the basis of control for all compaction effort.
FIELD DENSITY AND MOISTURE TESTS
The In -place density and moisture content of compacted fill will be
determined by the geotechnical engineer or his representative in
accordance with ASTM D 1556 (sand cone method) or ASTM D 2922, D
3011 (nuclear methods). Material not meeting the required compaction
and/or moisture specifications shall be recompacted and/or moisture
conditioned until the required percent compactlone and/or moisture content Is
obtained. Sufficient compaction tests shall be made and submitted to support
the geotechnical engineer's or his representative's recommendations.
The results of density tests will also be furnished to the
client and others as directed. C-
4