HomeMy WebLinkAboutPOUDRE PLAINS SUBDIVISION - PRELIMINARY - 72-87 - SUBMITTAL DOCUMENTS - ROUND 1 - STREET RELATED DOCUMENT •
REPORT
OF A
PAVEMENT DESIGN
FOR
•
POUDRE PLAINS SUBDIVISION
FORT COLLINS, COLORADO
MR. JIM SABIN
TIMNATH, COLORADO
PROJECT NO. 7321-87
BY
EMPIRE LABORATORIES, INC.
301 NORTH HOWES STREET
FORT COLLINS, COLORADO 80521
4110
•
TABLE OF CONTENTS
Table of Contents
Letter of Transmittal
Report 1
Appendix A i A-1
Test Boring Location Plan A-2
Key to Borings A-3
Log of Borings A-4
Appendix B B-1
Hveem Stabilometer Data B-2
Summary of Test Results B-3
Appendix C C-1
0 . • •
. • Empire Laboratories, Inc. -
- P.O.Box 503 • (303)484-0359
GEOTECHNICAL ENGINEERING&MATERIALS TESTING 301 No.Howes • Fort Collins,Colorado 80522
December 16, 1987
Mr. Jim Sabin
P. O. Box 125
Timnath, Colorado 80547
Dear Mr. Sabin:
We are pleased to submit our Report of a Pavement Design prepared for
the Poudre Plains Subdivision located on West Vine Drive in northwest
Fort Collins,. Colorado. ,
The accompanying report presents our findings in the subsurface and our
recommendations for pavement design based upon these findings.
Very truly yours,
;
EMPIRE LABORA RIES, INC. -,5�� �",'r,i i; .''e,,
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Senior Engineering Geologist Fy�...,,,• -;; ,> /
E/(R . C.,.„,
Reviewed by: .,%%. ar '''.f.4:://:::40..e.........2d, ...t:::.•\>.,,,...,.. •... li, ..4.•
Chester C. Smith P.E. :" o
President • 4808 }'
fs.'e ?, ';o'''*
CIO. • '• jT ,
cc: Stewart & Associates Mr. Dick RI th rford
p� Branch Offices
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Z. P.O.Box 1135 P.O.Box 1744 P.O.Box 10076
Longmont,Colorado 80502 Greeley,Colorado 80632 Cheyenne,Wyoming 82003
�� �? (303)776-3921 (303)351-0460 (307)632 9224
Member of Consulting Engineers Council
Afie
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REPORT
OF A .
PAVEMENT DESIGN
SCOPE
This report presents the results of a pavement design prepared for
Poudre Court, North Briarwood Road and the widening of West Vine Drive
in the Poudre Plains Subdivision in northwest Fort Collins, Colorado.
The scope of the project included test borings and laboratory testing of
samples obtained from these borings.
The objectives of this study were to (1) determine the soil and
ground water conditions at the site, (2) develop criteria for determining
pavement design, and (3) 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 December 7, 1987, consisted of
drilling, logging, and sampling two (2) test borings. 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 operation,
a field engineer from Empire Laboratories, Inc. was present and made
continuous observations of the soils encountered.
SITE LOCATION AND DESCRIPTION
The proposed site is located on West Vine Drive west of Taft Hill
Road in northwest Fort Collins, Colorado. More particularly, the site is
described as Poudre Plains Subdivision, a tract of land situate in the
-1
Northeast 1 /4 of Section 9, Township 7 North, Range 68 West of the Sixth
P.M. , Larimer County, Colorado.
The site consists of an open field vegetated with grass and weeds.
The property is relatively flat and has minor drainage to the south.
Small irrigation laterals traverse the site from northwest to the southeast.
An existing church is located to the east, residences to the west and
open areas to the south. The property is bordered on the north by West.
Vine Drive.
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,
laboratory resistivity, pH, sulfides, oxidation-reduction potential, pH,
and the Atterberg limits were determined. A summary of the test results
is included in Appendix B. A Hveem stabilometer test was run to
determine the "R" value of representative subgrade material at the site,
and a curve showing this,data is 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 ) Topsoil: The area tested is overlain by a one (1) foot layer of
silty topsoil. The upper six (6) inches of the topsoil has been
penetrated by root growth and organic matter and should not
be used as a roadway subgrade. It is recommended that the
topsoil be stripped and stockpiled for reuse in planted areas or
wasted from the site.
(2) Sandy and/or Sandy Gravelly Silty Clay: This stratum
underlies the topsoil and extends to the sand and gravel below
-2-
0
and/or the depths explored. The silty clay contains varying
amounts of silt and/or gravel, is moderately plastic, and is dry
to damp in situ. When wetted, the clay stratum exhibits low
subgrade bearing characteristics.
(3). Clayey Sand and Gravel: A layer of clayey sand and gravel
underlies the sandy silty clay in Boring 1 at a depth of five
and one-half (5-1 /2) feet-below the surface and extends beyond
the depths explored. The sand and gravel contains varying
amounts of clay, is poorly graded, and is medium dense.
(4) Ground Water: At the time of the investigation, 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.
-RECOMMENDATIONS AND DISCUSSION
It is our understanding that Poudre Court and North Briarwood Road
to be constructed at the site are residential streets. West Vine Drive,
which is to be widened adjacent to the project area, is classified as an
arterial street by the City of Fort Collins.
Site Grading and Utilities_.
•
It is recommended that the upper six (6) inches of topsoil
encountered at the site be stripped and stockpiled for reuse in planted
areas. The upper six (6) inches of the natural subgrade below should be
scarified and recompacted at or wet of optimum moisture to at least
ninety-five percent (95$) of Standard Proctor Density ASTM D 698-78.
(See Appendix C.)
All fill should consist of the on-site soils or imported material having
an "R" value of 10 or greater, and this material should be approved by
the geotechnical engineer. Any fill placed at the site should be placed in
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111
uniform six (6) to eight (8) inch lifts and compacted at or wet of optimum
moisture to at least ninety-five percent. (95%) of Standard Proctor Density
ASTM D 698-78. The finished subgrade in cut sections below streets
should be scarified a minimum of six (6) inches and recompacted at or wet
of optimum moisture to at least ninety-five percent (95%) of Standard
Proctor Density ASTM D 698-78. In areas where subgrade compaction
cannot be met due to unstable conditions, ' the subgrade should be
stabilized by use of granular pit run or geotextiles. Each successive lift
of fill placed on slopes should be benched slightly into existing grade.
Utility trenches dug four (4) feet or more into the upper soils
should be excavated on safe -and stable slopes in accordance with OSHA
regulations, or the excavations should be properly shored. 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 Gifts 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 streets 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.
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
noncorrosive, and protection of metal utility pipe, in our opinion, will not
be required.
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411
Flexible 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 asphaltic concrete underlain by crushed aggregate base course
or asphaltic 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 2.0 for Poudre Court and North
Briarwood Road and 2.5 for West Vine Drive, a regional factor of 1 .0, an
"R" value of 10, a twenty ' (20) year design life, eighteen (18) kip
equivalent daily load applications of 5 for Poudre Court, 10 for North
Briarwood Road and 130 for West Vine Drive, and weighted structural
numbers of 2.10 for Poudre Court, 2.35 for North Briarwood Road and
3.70 for West Vine Drive, the following minimum pavement thicknesses are.
recommended:
Poudre Court
Asphaltic Concrete 3"
Crushed Aggregate Base Course 7"
Total Pavement Thickness 10"
Asphaltic Concrete 2"
Plant Mix Bituminous Base Course 31"
Total Pavement Thickness 51" -
North Briarwood Road
Asphaltic Concrete 3"
Crushed Aggregate Base Course 9"
Total Pavement Thickness 12"
Asphaltic Concrete 2"
Plant Mix Bituminous Base Course 41"
Total Pavement Thickness 61"
-5-
' *
West Vine Drive
Asphaltic Concrete 3"
Plant Mix Bituminous Base Course 7"
Total Pavement Thickness 10"
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 and Utilities" section of this report. Upon proper
preparation of the subgrade, the subbase and base course should be
placed and compacted at optimum moisture to at least ninety-five percent
(95%) of Standard Proctor Density ASTM D 698-78. (See Appendix C. )
It is recommended that the asphaltic 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 asphaltic concrete shall meet City of
Fort Collins specifications and should be placed in accordance with these
specifications. The crushed aggregate base course shall have an "R"
value of 78 or greater, the plant mix bituminous base course shall have
an Rt value of 90 or greater, and the asphaltic 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
asphaltic 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 five (105) pounds
per square inch per inch based on an "R" value of 10, 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 thicknesses are recommended:
-6-
Poudre Court and North Briarwood Road
Nonreinforced Concrete - 5"
West Vine Drive
Nonreinforced Concrete - 7"
Subgrade below proposed streets should be prepared in accordance with
the recommendations discussed in the "Site Grading 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 shalt conform to ASTM C-33
specifications. The concrete 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 COMMENTS
This report has been prepared to aid in the evaluation of the
property and to assist the engineer in the design of this project. In the
event that any changes in the street grade or designs are planned, the
-7-
conclusions and recommendations contained in this report will not be
considered valid 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 feasible. Variations in soil and ground water
conditions 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 subgrade preparation, fill
placement, and paving 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 subgrade
preparation and pavement placement.
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•
•
APPENDIX A.
0
TEST BORING LOCATION PLAN
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A-2
EMPIRE LABORATORIES. INC.
• • KEY TO BORING LOGS
i 00� TOPSOIL • GRAVEL
FILL ,• .•' SAND& GRAVEL
•/e SILT •i SILTY SAND&GRAVEL
i i ,•
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:ice CLAYEY SILT oo O COBBLES
•
•i�' SANDY SILT d• SAND,GRAVEL&COBBLES
CLAY imin WEATHERED BEDROCK
SILTY CLAY SILTSTONE BEDROCK
SANDY CLAY aimCLAYSTONE BEDROCK
.v '• ' SAND ® SANDSTONE BEDROCK
/ ••,� SILTY SAND MINE LIMESTONE
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CLAYEY SAND ® GRANITE
A SANDY SILTY CLAY
a
SHELBY TUBE SAMPLE
{I STANDARD PENETRATION DRIVE SAMPLER
WATER TABLE 24 HOURS AFTER DRILLING
r. HOLE CAVED
5/12 Indicates that 5 blows of a 140 pound hammer falling 30 inches was required to penetrate 12 inches.
A-3
_____._ _.._..__ _ FMPIRF I At ORATORIES Illr,.
•
LOG OF BORINGS
E.VArloL1 1-10. 00.0
100
• . •
6/12
95 ' ' • i.
13/12 ; 4/12
3/12 •••• '.
•: 3/12 • 7•
•
90
37/12
35
IBM, center line West Vine Drive opposite nortfitvest property
corner, el eeati on = 100.0' .
A-4
EMPIRE LABORATORIES, INC.
APPENDIX B.
•
RESISTANCE R-VALUE AND EXPANSION PRESSURE
•
OF COMPACTED SOIL
ASTM D 2844 •
•
CLIENT: JIM SABIN
PROJECT: POUDRE PLAINS SUBDIVISION •
LOCATION OF SAMPLE: BORING 2 COMPOSITE @ 1 . U'-3. 0'
•
SAMP.LE_.DATA
TEST SPECIMEN 1 2 ._ 3
COMPACTION PRESSURE - PSI 80 ' 11.0 130
DENSITY - PCF 105. 6 113. 1 114. 5
MOISTURE - •i. 20. 5 18. 1 17. 2
EXPANSION PRESSURE - PSI 0. 00 0. 00 0. 00
HORIZONTAL PRESSURE-0 160 psi 141-. 131 125
SAMPLE HEIGHT - in. 2. 53 2. 44 • 2, 46
EXUDATION PRESSURE PSI 205 380 493
UNCORRECTED R-VALUE 7.7 14. 4 17. 2
CORRECTED R-VALUE 7. 7 14. 0 17. 2
R-VALUE AT 300 .PSI EXUDATION PRESSURE = 10. 6
1.00
1.1 60 P _ p........... ......4.----..-..
x
Q4 0 ............
• 100 . 200 300 400 500 800 700 800
• EXUDATION PRESSURE - psi
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SUMMARY OF TEST RESULTS
Boring Depth Resistivity Oxidation-Reduction
No. (Ft. ) (ohm/cm) Potential (mV) Sulfide pH
2 1.0-3.0 3200 163 trace 8.0
B-4
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 fill 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 proposed for use as fill shall be approved by the
geotechnical engineer or his representative prior to use. Proposed import
material shall be approved.... by the geotechnical engineer or his
representative prior to hauling to the project site. Fill material shall be
• 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 sheepsfoot 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 D 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
3017 (nuclear methods). Material not meeting the required compaction
and/or moisture specifications shall be recompacted and/or moisture
conditioned until the required percent compaction 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