HomeMy WebLinkAboutHARMONY MARKET PUD, 9TH FILING - PRELIMINARY & FINAL - 54-87X - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTTHIS GEOTECHNICAL REPORT IS FOR HARMONY
MARKET 9TH FILING, NOT THE 6TH FILING AS
INDICATED IN THE TEXT.
GEOTECHNICAL ENGINEERING REPORT
PROPOSED CONVENIENCE STORE
HARMONY MARKEV,.6TH FILING
FORT COLLINS, COLORADO
ELI PROJECT NO. 20945132
A Division of
The Terracon Companies, Inc.
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GEOTECHNICAL ENGINEERING REPORT
PROPOSED CONVENIENCE STORE
41 HARMONY MARKET 6TH FILING
FORT COLLINS, COLORADO
ELI PROJECT NO. 20945132
Prepared for.
TYCO OIL COMPANY
3512 LOCKWOOD DRIVE
FORT COLLINS, COLORADO 80525
ATTN: MR. MARK TINGERY
Empire Laboratories, Inc.
A Division of the Terracon Companies, Inc.
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Empire Laboratories, Inc.
A Division of The Terracon Companies, Inc.
P.O. Box 503 • 301 No. Howes
Fort Collins. Colorado 80522
(303) 484-0359
FAX No. (303) 484-0454
Chester C. Smith, P.E.
Neil R. Sherrod, C.PG.
June 29, 1994
Tyco Oil Company
3512 Lockwood Drive
Fort Collins, Colorado 80525
Attn: Mr. Mark Tingery
Re: Geotechnical Engineering Report, Proposed Convenience Store
Harmony Market 6th Filing
Fort Collins, Colorado
ELI Project No. 20945132
Empire Laboratories, Inc. (ELI) has completed a geotechnical engineering exploration for the
proposed convenience store to be located at southwest corner of Harmony Road and South Lemay
Avenue in southeast Fort Collins, Colorado. This study was performed in general accordance with
our proposal number D2094218 dated June 22, 1994.
The results of our engineering study, including the boring location diagram, laboratory test results,
test boring records, and the geotechnical recommendations needed to aid in the design and
construction of foundations and other earth connected phases of this project are attached.
The subsurface soils at the site consisted of lean clay with sand and sandy lean clay underlain by
clayey sand with gravel. The information obtained from the field exploration and laboratory testing
indicates the soils have low expansive potential and moderate bearing characteristics.
Groundwater was encountered at approximate depths of 8'/z feet.
Based on the geotechnical engineering analyses, subsurface exploration and laboratory test results,
we recommend that the proposed building be supported on a spread footing and/or grade beam
foundation system. Slab -on -grade may be utilized for the interior floor system provided that care
is taken in the placement and compaction of the subgrade soil. Due to the depth to groundwater,
anchoring of the proposed underground storage tanks may be required.
Other design and construction details, based upon geotechnical conditions, are presented in the
report.
Offices of The Terracon Companies, Inc. Geotechnical, Environmental and Materials Engineers
Arizona: Tucson ■ Colorado: Colorado Springs, Denver, Ft. Collins, Greeley. Longmont ■ Idaho: Boise ■ Illinois. Bloomington,
Chicago, Rock Island ■ Iowa: Cedar Falls, Cedar Rapids, Davenport, Des Moines, Storm Lake ■ Kansas: Lenexa, Topeka,
Wichita ■ Minnesota: St. Paul ■ Missouri: Kansas City ■ Nebraska: Lincoln, Omaha ■ Nevada: Las Vegas
■ Oklahoma: Oklahoma City, Tulsa ■ Texas: Dallas, Fort Worth ■ Utah: Salt Lake City ■ Wyoming: Cheyenne
QUALITY ENGINEERING SINCE 1965
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Tyco Oil Company Terracon
ELI Project No. 20945132
We have appreciated being of service to you in the geotechnical engineering phase of this project
and are prepared to assist you during the construction phase as well. If you have any questions
concerning this report or any of our testing, inspection, design and consulting services, please do
not hesitate to contact us.
Sincerely,
EMPIRE LABORATORIES, INC.
A Division of The Terracon Companies, Inc. ,kl-PG , a
Z G f.
Neil R. Sherrod
Senior Engineering Geologist
Reviewed by: ```\�N
. P O RED jsT
G.
(3L&AI
<�73_ _ \ _ _
:v• Fr.p�
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22750
Larry G. O'Dell, P.E.
Office Manager�.� •.• �`�
NRS/LGO/cic "/ONAL,�U
Copies to: Addressee (3)
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Tyco Oil Company
ELI Project No. 20945132
TABLE OF CONTENTS
Terracon
Page No.
Letterof Transmittal................................................... ii
INTRODUCTION.....................................................
1
PROPOSED CONSTRUCTION ...........................................
1
SITE EXPLORATION ..................................................
2
Field Exploration
2
...............................................
LaboratoryTesting ..............................................
2
SITECONDITIONS ................................................... 3
3
SUBSURFACE CONDITIONS ............................................
3
Geology.....................................................
4
SoilConditions ...............................................
4
LaboratoryTest Results ..........................................
4
GroundwaterConditions ..........................................
CONCLUSIONS AND RECOMMENDATIONS .................................
5
5
Site Development Considerations .....................................
5
FoundationSystems .............................................
6
UndergroundStorage Tanks .......................................
6
Lateral Earth Pressures ...........................................
7
Seismic Considerations ...........................................
7
Floor Slab Design and Construction ..................................
Pavement Design and Construction ..................................
8
12
Earthwork...................................................
SiteClearing
12
............................................
12
Excavation.............................................
12
Slab Subgrade Preparation ...................................
13
PavementSubgrade Preparation ...............................
FillMaterials
13
............................................
14
Placementand Compaction ..................................
15
Slopes................................................
15
Compliance.............................................
15
Excavation and Trench Construction ............................
16
Drainage....................................................
16
SurfaceDrainage .........................................
17
Additional Design and Construction Considerations ......................
17
Exterior Slab Design and Construction ..........................
17
Corrosion Protection .......................................
17
GENERAL COMMENTS ...............................................
Tyco Oil Company Terracon
ELI Project No. 20945132
TABLE OF CONTENTS (Cont'd)
Page No.
APPENDIX A
Figure No.
SitePlan ...................................................... 1
Logs of Borings .......................................... Al thru A3
APPENDIX B
Swell -Consolidation Test .......................................... B 1
Summary of Test Results ......................................... B2
APPENDIX C: GENERAL NOTES
Drilling & Exploration ............................................ C1
Unified Soil Classification ......................................... C2
Laboratory Testing, Significance and Purpose ........................... C3
Report Terminology ............................................. C4
APPENDIX D
Recommended Preventative Maintenance -Asphalt Concrete Pavements ......... D1
Recommended Preventative Maintenance -Jointed Concrete Pavements ......... D2
■ GEOTECHNICAL ENGINEERING REPORT Terracon
PROPOSED CONVENIENCE STORE
HARMONY MARKET 6TH FILING
FORT COLLINS, COLORADO
ELI PROJECT NO. 20945132
JUNE 29, 1994
INTRODUCTION
. This report contains the results of our geotechnical engineering exploration for the convenience
store to be located in the 6th Filing of Harmony Market at the southwest corner of Lemay Avenue
t and Harmony Road in southeast Fort Collins, Colorado. The site is located in the Northeast 1 /4
of Section 1, Township 7 North, Range 69 West of the 6th Principal Meridian.
. The purpose of these services is to provide information and geotechnical engineering
recommendations relative to:
• subsurface soil conditions
• groundwater conditions
. • foundation design and construction
• lateral earth pressures
0 floor slab design and construction
• pavement design and construction
• earthwork
. 0 drainage
The conclusions and recommendations contained in this report are based upon the results of field
. and laboratory testing, engineering analysis, and experience with similar soil and structural
conditions.
. PROPOSED CONSTRUCTION
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The project as we understand it will be to construct a convenience store consisting of a store, car
wash and pump island. The store and car wash will be single -story, slab -on -grade, masonry
structures. Four underground storage tanks will be placed in the area between the convenience
store and car wash. A pump island with overhead canopy is planned north and west of the store.
Parking and drive areas will surround the structure. A small detention area will be located in the
southeast corner of the site. An existing drainage swale through the property will be filled. The
finished first floor of the new convenience store and car wash will be at or slightly above existing
grade. It is anticipated the proposed buildings will exhibit light loads.
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Tyco Oil Company Terracon
ELI Project No. 20945132
SITE EXPLORATION
The scope of the services performed for this project included a site reconnaissance by an
engineering geologist, a subsurface exploration program, laboratory testing and engineering
analysis.
Field Exploration: A total of three test borings were drilled on June 23, 1994 to depths of 15 feet
at the locations shown on the Site Plan, Figure 1. Two borings were drilled within the footprint
of the proposed buildings, and one boring was drilled in the area of proposed pump island and
canopy. All borings were advanced with a truck -mounted drilling rig, utilizing 4-inch diameter
solid stem auger.
The borings were located in the field from existing adjacent buildings. Elevations were taken at
each boring location by measurements with an engineer's level from a temporary bench mark
(TBM) shown on the Site Plan. The accuracy of boring locations and elevations should only be
assumed to the level implied by the methods used.
Continuous lithologic logs of each boring were recorded by the engineering geologist during the
drilling operations. At selected intervals, samples of the subsurface materials were taken by
pushing thin -walled Shelby tubes, or driving split -spoon samplers.
Penetration resistance measurements were obtained by driving the split -spoon into the subsurface
materials with a 140-pound hammer falling 30 inches. The penetration value is a useful index to
the consistency, relative density or hardness of the materials encountered.
aGroundwater measurements were made in each boring at the time of site exploration, and 24
hours after drilling.
Laboratory Testing: All samples retrieved during the field exploration were returned to the
laboratory for observation by the project geotechnical engineer and were classified in accordance
with the Unified Soil Classification System described in Appendix C. At that time, the field
descriptions were confirmed or modified as necessary, an applicable laboratory testing program
was formulated to determine engineering properties of the subsurface materials.
Selected soil samples were tested for the following engineering properties:
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Tyco Oil Company Terracon
ELI Project No. 20945132
IN
• Water content • Expansion
• Dry density • Plasticity
• Consolidation • Soluble sulfate content
• Compressive strength
The significance and purpose of each laboratory test is described in Appendix C. Laboratory test
9 P P Y PP
results are presented in Appendix B, and were used for the geotechnical engineering analysis, and
the development of foundation and earthwork recommendations. All laboratory tests were
performed in general accordance with the applicable ASTM, local or other accepted standards.
SITE CONDITIONS
The site is a relatively flat area located between an existing lube shop and bank under
■ construction. The area is vegetated with grasses and alfalfa. A natural drainage runs southeast
through the center of the site, and drainage is to the swale and southeastward.
SUBSURFACE CONDITIONS
i_ Geology: The project area is located within the Colorado Piedmont section of the Great Plains
physiographic province. The Colorado Piedmont, formed during Late Tertiary and Early quaternary
time (approximately 2,000,000 years ago), is a broad, erosional trench which separates the
Southern Rocky Mountains from the High Plains:. Structurally, the site lies along the western flank
of the Denver Basin. During the Late Mesozoic and Early Cenozoic Periods (approximately
■ 70,000,000 years ago), intense tectonic activity occurred, causing the uplifting of the Front Range
and associated downwarping of the Denver Basin to the east. Relatively flat uplands and broad
. valleys characterize the present-day topography of the Colorado Piedmont in this region. The site
is underlain by the Cretaceous Pierre formation. It is estimated the Pierre shale underlies the site
_ at approximate depths of 20 feet. The Pierre shale is overlain by residual and alluvial soils of
Pleistocene and/or Recent age.
Mapping completed by the Colorado Geological Survey ('Hart, 1972), indicates the site in an area
of "Moderate Swell Potential". Potentially expansive materials mapped in this area include
bedrock, weathered bedrock and colluvium (surficial units).
. 'Hart, Stephen S., 1972, Potenha/y Swe/Iing Sof7 and Rock in the Front Range Urban Corridor, Colorado, Colorado
Geological Survey, Environmental Geology No. 7.
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ELI Project No. 20945132
Soil Conditions: As presented on the Logs of Boring, the subsurface soils were encountered in
. order of increasing depths as follow:
• Silty Topsoil and Fill Material: The majority of the area tested is overlain by a 6-inch layer
. of silty topsoil. The topsoil has been penetrated by root growth and organic matter. A 1-
- foot layer of fill material was encountered at the surface of Boring 2. The fill consists of
lean clay with sand and gravel. It is not known whether the fill has been uniformly or
properly compacted. The fill is moist and very stiff in consistency.
• Lean Clay With Sand: This stratum underlies the topsoil and/or fill and extends to depths
of 1'/2 to 3%2 feet below the surface. The brown lean clay contains varying amounts of
sand, is moist and stiff to very stiff in consistency.
• Sandy Lean Clay: This stratum underlies the upper clays at depths of 1 %2 to 3'/2 feet and
extends to depths of 7 % to 12 feet. A lower layer of the clay stratum was encountered
in Boring 2 at a depth of 12 feet and extends beyond the depths explored. The red sandy
lean clay is moist to wet and medium to very stiff in consistency.
• Clayey Sand With Gravel: This stratum was encountered at depths of 7 %2 to 12 feet and
extends to depths of 12 feet to greater than 15 feet below the surface. The clayey sand
is slightly plastic, contains varying amounts of fine gravel, is wet and medium dense to
dense in relative density.
Laboratory Test Results: Laboratory test results indicate the subsoils at shallow depth have slight
swell potential and moderate bearing characteristics.
Groundwater Conditions: Groundwater was observed at approximate depths of 8 %2 to 9'/2 feet
in the test borings at the time of field exploration. When checked 24 hours after drilling,
groundwater was measured at approximate depths of 8'/2 feet. These observations represent only
current groundwater conditions, and may not be indicative of other times, or at other locations.
Groundwater levels can be expected to fluctuate with varying seasonal and weather conditions.
Based upon review of U.S. Geological Survey maps (2 Hillier, et al, 1983), regional groundwater
is expected to be encountered in unconsolidated alluvial deposits on the site, at depths ranging
from 10 to 20 feet below the existing ground surface at the project site.
ZHillier, Donald E.; Schneider, Paul A., Jr.; and Hutchinson, E. Carter, 1983, Depth to Water Table (1979) in the Boulder -Fort
Collins -Greeley Area, Front Range Urban Corridor, Colorado, United States Geological Survey, Map 1-855-I.
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ELI Project No. 20945132
The possibility of groundwater fluctuations should be considered when developing design and
construction plans for the project.
aCONCLUSIONS AND RECOMMENDATIONS
Site Development Considerations: The site appears suitable for the proposed construction.
Potentially expansive soils and the relatively shallow depth to groundwater will require particular
attention in the design and construction.
Because of the engineering properties of the on -site soils, foundation bearing levels, anticipated
light structural loads, and proposed final grades, the following foundation systems were evaluated
for use on the site:
• spread footings and/or grade beams bearing on undisturbed soils; and,
• spread footings and/or grade beams bearing on engineered fill.
Slab -on -grade construction is considered acceptable for the on -site soils provided that design and
construction recommendations are followed. Anchoring of underground storage tanks may be
required due to shallow depths to groundwater.
Foundation Systems: Due to the presence of non- to low -swelling soils on the site, spread footing
foundations bearing upon undisturbed subsoils and/or engineered fill are recommended for support
for the proposed structure. The footings may be designed for a maximum bearing pressure of
1,500 psf. In addition, the footings should be sized to maintain a minimum dead -load pressure
of 250 psf. Exterior footings should be placed a minimum of 30 inches below finished grade for
frost protection. Interior footings should bear a minimum of 12 inches below finished grade.
Existing fill should not be used for support of foundations without removal and recompaction.
Finished grade is the lowest adjacent grade for perimeter footings and floor level for interior
footings. The design bearing capacities apply to dead loads plus design live load conditions. The
design bearing capacity may be increased by one-third when considering total loads that include
wind or seismic conditions.
Footings should be proportioned to minimize differential foundation movement. Proportioning on
the basis of equal total settlement is recommended; however, proportioning to relative constant
dead -load pressure will also reduce differential settlement between adjacent footings. Total or
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Tyco Oil Company Terracon
ELI Project No. 20945132
differential settlement resulting from the assumed structural loads are estimated to be on the order
of 3/4 inch, provided that foundations are constructed as recommended.
Additional foundation movements could occur if water from any source infiltrates the foundation
. soils; therefore, proper drainage should be provided in the final design and during construction.
Footings for the proposed canopy may be designed to resist uplift using the equation presented
below:
T„=.IxYxDZx(B+L)+W
Where: T„ = Ultimate uplift capacity (Ibs)
Y = Unit weight of soil (Ibs/ft3) *
D = Depth to base of footing foundation below final grade (ft)
B = Width of footing foundation (ft)
L = Length of footing foundation (ft)
W = Weight of footing + weight of soil directly over the top of the
footing/block (Ibs)
*A unit weight (Y) of 125 pcf is recommended for soil (either undisturbed
or compacted backfill) at this site.
. The design uplift resistance should be calculated by dividing the ultimate resistance obtained from
the equation above by an appropriate factor of safety. A factor of safety of at least 2 is
recommended for live uplift loads in the analysis.
Underground Storage Tanks: We understand the underground storage tanks will be 8-feet in
diameter. In view of this, it is anticipated the bottom of the tanks will be placed at or below
existing groundwater. Therefore, temporary dewatering will be required during excavation for the
tanks, and anchoring of the tanks may be necessary to resist hydrostatic uplift. Foundations for
the tanks should be designed using the soil data described above.
Lateral Earth Pressures: For soils above any free water surface, recommended equivalent fluid
pressures for unrestrained foundation elements are:
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ELI Project No. 20945132
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Terracon
• Active:
Cohesive soil backfill (on -site clay) .......................... 40 psf/ft
Cohesionless soil backfill (on -site sand) ....................... 35 psf/ft
• Passive:
Cohesive soil backfill (on -site clay) ......................... 350 psf/ft
Cohesionless soil backfill (on -site sand) ...................... 450 psf/ft
• Coefficient of base friction ................................. 0.30
• Adhesion at base of footing ............................... 500 psf
Where the design includes restrained elements, the following equivalent fluid pressures are
recommended:
• At rest:
Cohesive soil backfill (on -site clay) .......................... 60 psf/ft
Cohesionless soil backfill (on -site sand) ....................... 55 psf/ft
In addition, hydrostatic pressures below groundwater should be taken into account in the design
of the tanks.
Fill against grade beams and retaining walls should be compacted to densities specified in
"Earthwork". Compaction of each lift adjacent to walls should be accomplished with hand -
operated tampers or other lightweight compactors. Overcompaction may cause excessive lateral
earth pressures which could result in wall movement.
Seismic Considerations: The project site is located in Seismic Risk Zone I, of the Seismic Zone
Map of the United States as indicated by the Uniform Building Code. Based upon the nature of
the subsurface materials, a seismic site coefficient, "s" of 1.0 should be used for the design of
structures for the proposed project (Uniform Building Code, Table No. 23-J).
Floor Slab Desiqn and Construction: Low -swelling natural soils or engineered fill will support the
floor slab. Some differential movement of a slab -on -grade floor system is possible should the
subgrade soils become elevated in moisture content. Such movements are considered within
general tolerance for normal slab -on -grade construction. To reduce any potential slab movements,
the subgrade soils should be prepared as outlined in the earthwork section of this report.
• Tyco Oil Company Terracon
ELI Project No. 20945132
For structural design of concrete slabs -on -grade, a modulus of subgrade reaction to 100 pounds
per cubic inch (pci) may be used for floors supported on existing or engineered fill consisting of
on -site soils.
0 Additional floor slab design and construction recommendations are as follows:
• Positive separations and/or isolation joints should be provided between slabs and
all foundations, columns or utility lines to allow independent movement.
• Contraction joints should be provided in slabs to control the location and extent of
cracking. Maximum joint spacing of 15 to 20 feet in each direction is
recommended.
• Interior trench backf ill paced beneath slabs should be compacted in accordance with
recommended specifications outlined below.
• In areas subjected to normal loading, a minimum 4-inch layer of clean -graded gravel
should be placed beneath interior slabs. For heavy loading, 6 inches of crushed
aggregate base course should be used.
• If moisture sensitive floor coverings are used on interior slabs, consideration should
be given to the use of barriers to minimize potential vapor rise through the slab.
• Floor slabs should not be constructed on frozen subgrade.
• Other design and construction considerations, as outlined in the ACI Design Manual,
Section 302.1 R are recommended.
Pavement Design and Construction: The required total thickness for the pavement structure is
dependent primarily upon the foundation soil or subgrade and upon traffic conditions. Based on
the soil conditions encountered at the site, the type and volume of traffic and using a group index
of 10 as the criterion for pavement design, the following minimum pavement thicknesses are
recommended:
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Tyco Oil Company Terracon
ELI Project No. 20945132
Recommended Pavement Section Thickness
(Inches)
Traffic Area
Alterna-
tive
Asphalt
Aggregate
Plant Mix
Portland
Concrete
Base
Bituminous
Cement
TOTAL
Surface
Course
Base Course
Concrete
A
3"
6"
9"
B
2"
3"
5"
Automobile
Parking
C
5"
5"
A
3"
10"
13"
B
2"
4'/2 "
E6"
Drive Areas
C
6"
Each alternative should be investigated with respect to current material availability and economic
conditions.
Aggregate base course (if used on the site) should consist of a blend of sand and gravel which
meets strict specifications for quality and gradation. Use of materials meeting Colorado
Department of Transportation Class 5 or 6 specifications is recommended.
Aggregate base course should be placed in lifts not exceeding six inches and should be compacted
to a minimum of 95% Standard Proctor density (ASTM D698), within a moisture content range
of 2 percent below to 2 percent above optimum. Where base course thickness exceeds 6 inches,
the material should be placed and compacted in two or more lifts of equal thickness.
Asphalt concrete should be obtained from an approved mix design stating the Hveem properties,
optimum asphalt content, job mix formula, and recommended mixing and placing temperatures.
Aggregate used in asphalt concrete should meet a particular gradation. Use of materials meeting
Colorado Department of Transportation Grading C or CX specification is recommended. The mix
design should be submitted prior to construction to verify its adequacy. The asphalt materials
should be placed in maximum 3-inch lifts and should be compacted to a minimum of 95% Hveem
density (ASTM D1561).
Plant -mixed bituminous base course should be composed of a mixture of aggregate, filler and
additives if required and approved bituminous material. The bituminous base should conform to
an approved mix design stating the Hveem properties, optimum asphalt content, job mix formula,
and recommended mixing and placing temperatures. Aggregate used in plant -mixed bituminous
base course should meet a particular gradation. Use of aggregates meeting Colorado Department
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of Transforation Grading G or C specifications is recommended. The mix design should be
submitted prior to construction to verify it adequacy. The asphalt material should be placed in
maximum 3-inch lifts, and should be compacted to a minimum of 95% Hveem density (ASTM
D1561).
Where rigid pavements are used, the concrete should be obtained from an approved mix design
with the following minimum properties:
• Modulus of Rupture @ 28 days ........................ 650 minimum
• Strength Requirements ................................ ASTM C94
• Minimum Cement Content ......................... 5.5 sacks/cu. yd.
• Cement Type .................................... Type I Portland
• Entrained Air Content ................................... 6 to 8%
• Concrete Aggregate ................. ASTM C33 and CDOT Section 703
• Aggregate Size ................................. 1 inch maximum
• Maximum Water Content 0.49 lb/lb of cement
• Maximum Allowable Slump ............................... 4 inches
Concrete should be deposited by truck mixers or agitators and placed a maximum of 90 minutes
from time the water is added to the mix. Other specifications outlined by the Colorado
Department of Transportation should be followed.
Longitudinal and transverse joints should be provided as needed in concrete pavements for
expansion/contraction and isolation. The location and extent of joints should be based upon the
final pavement geometry and should be placed (in feet), at roughly twice the slab thickness (in
inches), on center in either direction. Sawed joints should be cut within 24-hours of concrete
placement, and should be a minimum of 25% of slab thickness plus 1/4 inch. All joints should
be sealed to prevent entry of foreign material and dowelled where necessary for load transfer.
Where dowels cannot be used at joints accessible to wheel loads, pavement thickness should be
increased by 25 percent at the joints and tapered to regular thickness in 5 feet.
Future performance of pavements constructed on the clay soils at this site will be dependent upon
several factors, including:
• maintaining stable moisture content of the subgrade soils; and,
• providing for a planned program of preventative maintenance.
Since the clay soils on the site have shrink/swell characteristics, pavements could crack in the
future primarily because of expansion of the soils when subjected to an increase in moisture
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ELI Project No. 20945132
content to the subgrade. The cracking, while not desirable, does not necessarily constitute
. structural failure of the pavement.
The performance of all pavements, but in particular the recommended asphalt sections, can be
. enhanced by minimizing excess moisture which can reach the subgrade soils. The following
recommendations should be considered at minimum:
. • Site grading at a minimum 2% grade away from the pavements;
• Compaction of any utility trenches for landscaped areas to the same criteria as the
pavement subgrade;
• Sealing all landscaped areas in or adjacent to pavements to minimize or prevent
moisture migration to subgrade soils;
• Placing compacted backfill against the exterior side of curb and gutter; and,
• Placing curb, gutter and/or sidewalk directly on subgrade soils without the use of
base course materials.
Preventative maintenance should be planned and provided for through an on -going pavement
management program in order to enhance future pavement performance. Preventative
maintenance activities are intended to slow the rate of pavement deterioration, and to preserve
the pavement investment.
Preventative maintenance consists of both localized maintenance (e.g. crack sealing and patching)
- and global maintenance (e.g. surface sealing). Preventative maintenance is usually the first priority
when implementing a planned pavement maintenance program and provides the highest return on
investment for pavements.
Recommended preventative maintenance policies for asphalt and jointed concrete pavements,
based upon type and severity of distress, are provided in Appendix D. Prior to implementing any
maintenance, additional engineering observation is recommended to determine the type and extent
of preventative maintenance.
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ELI Project No. 20945132
Earthwork:
• Site Clearing:
1. Strip and remove existing vegetation, debris, and other deleterious materials from
proposed building and pavement areas. All exposed surfaces should be free of
mounds and depressions which could prevent uniform compaction.
2. If unexpected fills or underground facilities are encountered during site clearing,
such features should be removed and the excavation thoroughly cleaned prior to
backfill placement and/or construction. All excavations should be observed by the
geotechnical engineer prior to backfill placement.
3. Stripped materials consisting of vegetation and organic materials should be wasted
from the site, or used to revegetate exposed slopes after completion of grading
— operations. If it is necessary to dispose of organic materials on -site, they should be
placed in non-structural areas, and in fill sections not exceeding 5 feet in height.
4. All exposed areas which will receive fill, once properly cleared and benched where
necessary, should be scarified to a minimum depth of eight inches, conditioned to
near optimum moisture content, and compacted.
0 • Excavation:
1. It is anticipated that excavations for the proposed construction can be accomplished
with conventional earthmoving equipment.
2. Depending upon depth of excavation and seasonal conditions, groundwater may be
encountered in excavations on the site. Pumping from sumps may be utilized to
control water within excavations. Well points may be required for significant
groundwater flow, or where excavations penetrate groundwater to a significant
depth.
• Slab Subarade Preparation:
1. Where existing clay soils will support floor slab, the soils should be scarified,
moisture conditioned and compacted to a minimum depth of 8 inches.
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ELI Project No. 20945132
2. A minimum 4-inch layer of clean -graded gravel should be placed beneath slabs.
Slabs supporting heavy loads should be underlain by a minimum of 6 inches of
crushed aggregate base course.
a• Pavement Subgrade Preparation:
1. The subgrade should be scarified, moistened as required, and recompacted for a
minimum depth of 8 inches prior to placement of fill and pavement materials.
2. On -site clay soils may pump or become unstable or unworkable at high water
contents. Workability may be improved by scarifying and drying. Wet or saturated
soils may be encountered near existing grade in the swale which traverses the site.
Extensive drying or stabilization of the subgrade is anticipated in this area.
Overexcavation of wet zones and replacement with granular materials may be
necessary. Lightweight excavation equipment may be required to reduce subgrade
pumping.
Use of lime, fly ash, kiln dust, cement or geotextiles could also be considered as a
stabilization technique. Laboratory evaluation is recommended to determine the
effect of chemical stabilization on subgrade soils prior to construction.
• Fill Materials:
1. Clean on -site soils or approved imported materials may be used as fill material for
the following:
• general site grading • exterior slab areas
• foundation areas • pavement areas
• interior floor slab areas • foundation backfill
2. Select granular materials should be used as backfill behind walls which retain earth.
3. Frozen soils should not be used as fill or backfill.
4. Imported soils (if required) should conform to the following:
13
Tyco Oil Company
ELI Project No. 20945132
•
• Gradation (ASTM C136):
percent finer by weight
Terracon
6..
...................................................
100
3..
......................................
No.4 Sieve ...........................................
50-70
No. 200 Sieve ....................................... 25 (max)
• Liquid Limit ......................................... 30 (max)
• Plasticity Index ...................................... 15 (max)
5. Aggregate base should conform to Colorado Department of Transportation Class 5
or 6 specifications.
Placement and Compaction:
1. Place and compact fill in horizontal lifts, using equipment and procedures that will
produce recommended moisture contents and densities throughout the lift.
2. Uncompacted fill lifts should not exceed 10 inches loose thickness.
3. No fill should be placed over frozen ground.
4. Materials should be compacted to the following:
Minimum Percent
Material Compaction (ASTM 13698)
On -site soils:
Beneath foundations ............................ 98
Beneath slabs ................................ 95
Beneath pavements ............................ 95
Imported fill:
Beneath foundations ............................ 98
Beneath slabs ................................ 95
Beneath pavements ............................ 95
Aggregate base (beneath slabs) ......................... 95
14
IL
Tyco Oil Company Terracon
ELI Project No. 20945132
Miscellaneous backfill................................ 90
5. If a well defined maximum density curve cannot be generated by impact compaction
in the laboratory for any fill type, engineered fill should be compacted to a minimum
of 70 percent relative density by determined by ASTM D4253.
6. On -site and imported soils should be compacted within a moisture content range of
2 percent below, to 2 percent above optimum.
• Slopes:
1. For permanent slopes in compacted fill areas, recommended maximum
configurations for on -site materials are as follows:
Maximum Slope
` Material Horizontal:Vertical
Cohesive soils (clays and silts) ..................... 2 %2 :1
Cohesionless soils ............................... 3:1
Detention pond slopes ............................ 3:1
If steeper slopes are required for site development, stability analyses should be
completed to design the grading plan.
2. The face of all slopes should be compacted to the minimum specification for fill
embankments. Alternately, fill slopes can be over -built and trimmed to compacted
material.
• Compliance: Recommendations for slabs -on -grade, foundations and pavement elements
supported on compacted fills or prepared subgrade depend upon compliance with
"Earthwork" recommendations. To assess compliance, observation and testing should be
performed under the direction of the geotechnical engineer.
• Excavation and Trench Construction: Excavations into the on -site soils will encounter a
variety of conditions. Excavations into the clays can be expected to stand on relatively
15
I
Tyco Oil Company Terracon
ELI Project No. 20945132
steep temporary slopes during construction. However, caving of the clayey sand and
gravel soils may occur. Temporary dewatering will be required where trenches are
excavated below groundwater. The individual contractor(s) should be made responsible
for designing and constructing stable, temporary excavations as required to maintain
stability of both the excavation sides and bottom. All excavations should be sloped or
shored in the interest of safety following local, and federal regulations, including current
. OSHA excavation and trench safety standards.
The soils to be penetrated by the proposed excavations may vary significantly across the
. site. The preliminary soil classifications are based solely on the materials encountered in
widely spaced exploratory test borings. The contractor should verify that similar conditions
. exist throughout the proposed area of excavation. If different subsurface conditions are
encountered at the time of construction, the actual conditions should be evaluated to
determine any excavation modifications necessary to maintain safe conditions.
As a safety measure, it is recommended that all vehicles and soil piles be kept to a
minimum lateral distance from the crest of the slope equal to no less than the slope height.
The exposed slope face should be protected against the elements.
The contractor should retain a geotechnical engineer to monitor the soils exposed in all
excavations and provide engineering services for slopes. This will provide an opportunity
to monitor the soil types encountered and to modify the excavation slopes as necessary.
. It also offers an opportunity to verify the stability of the excavation slopes during
construction.
■ Drainage:
. • Surface Drainage:
1. Positive drainage should be provided during construction and maintained throughout
the life of the proposed facility. Infiltration of water into utility or foundation
excavations must be prevented during construction. Planters and other surface
features which could retain water in areas adjacent to the building or pavements
should be sealed or eliminated.
. 2. In areas where sidewalks or paving do not immediately adjoin the structure, we
recommend that protective slopes be provided with a minimum grade of
approximately 10 percent for at least 10 feet from perimeter walls. Backfill against
footings, exterior walls, and in utility and sprinkler line trenches should be well
16
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Tyco Oil Company
ELI Project No. 20945132
Terracon
compacted and free of all construction debris to reduce the possibility of moisture
infiltration.
3. Downspouts, roof drains or scuppers should discharge into splash blocks or
extensions when the ground surface beneath such features is not protected by
exterior slabs or paving.
4. Sprinkler systems should not be installed within 5 feet of foundation walls.
Landscaped irrigation adjacent to the foundation system should be minimized or
eliminated.
Additional Design and Construction Considerations:
• Exterior Slab Design and Construction: Exterior slabs -on -grade, exterior architectural
features, and utilities founded on, or in backfill may experience some movement due to the
volume change of the backfill. Potential movement could be reduced by:
• minimizing moisture increases in the backfill
• controlling moisture -density during placement of backfill
• using designs which allow vertical movement between the exterior features
and adjoining structural elements
• placing effective control joints on relatively close centers
• allowing vertical movements in utility connections
• Corrosion Protection: Results of soluble sulfate testing indicate that ASTM Type 1-II
Portland cement is suitable for all concrete on and below grade. Foundation concrete
should be designed in accordance with the provisions of the ACI Design Manual, Section
318, Chapter 4.
GENERAL COMMENTS
It is recommended that the Geotechnical Engineer be retained to provide a general review of final
design plans and specifications in order to confirm that grading and foundation recommendations
have been interpreted and implemented. In the event that any changes of the proposed project
are planned, the conclusions and recommendations contained in this report should be reviewed
and the report modified or supplemented as necessary.
17
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Tyco Oil Company Terracon
ELI Project No. 20945132
The Geotechnical Engineer should also be retained to provide services during excavation, grading,
foundation and construction phases of the work. Observation of footing excavations should be
performed prior to placement of reinforcing and concrete to conform that satisfactory bearing
materials are present and is considered a necessary part of continuing geotechnical engineering
services for the project. Construction testing, including field and laboratory evaluation of fill,
backfill, pavement materials, concrete and steel, should be performed to determine whether
applicable project requirements have been met. It would be logical for Empire Laboratories, Inc.
to provide these additional services since we are most qualified to determine consistency of field
conditions with those data used in our analyses.
The analyses and recommendations in this report are based in part upon data obtained from the
field exploration. The nature and extent of variations beyond the location of test borings may not
become evident until construction. If variations then appear evident, it may be necessary to
reevaluate the recommendations of this report.
Our professional services were performed using that degree of care and skill ordinarily exercised,
under similar circumstances, by reputable geotechnical engineers practicing in this or similar
localities. No warranty, express or implied, is made. We prepared the report as an aid in design
of the proposed project. This report is not a bidding document. Any contractor reviewing this
report must draw his own conclusions regarding site conditions and specific construction
techniques to be used on this project.
This report is for the exclusive purpose of providing geotechnical engineering and/or testing
information and recommendations. The scope of services for this project does not include, either
specifically or by implication, any environmental assessment of the site or identification of
contaminated or hazardous materials or conditions. If the owner is concerned about the potential
for such contamination, other studies should be undertaken.
18
A�
��.•.I, 1i�-riT 1� o. Z 32
Empire Laboratories, Inc.
A Division of The Terracon Companies, Inc.
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LOG OF BORING No. 1 Page 1 of 1
CLIENT
ARCHITECT/ENGINEER
Tyco Oil Company
SITE Harmony Market 6th Filing
PROJECT
Fort Collins, Colorado
Proposed Convenience Store
SAMPLES
TESTS
F-
V
>-
F—
0
CD
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J
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DESCRIPTION
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W
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F- O
to
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ow
U X LL
WHO..
F- E\
0
Approx. Surface Elev.: 97.5 ft.
W
O
O
z
Z
r
F-
W
D:
U) J
Um
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U
0 0-
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^^^^^
6" TOPSOIL 97.0
1
SS
12"
10
19.6
35/18/17
^
0.5
LEAN CLAY WITH SAND
CL
1.5 Brown, moist, stiff 96.0
SANDY LEAN CLAY
Tan/red, moist to wet, medium stiff
CL
2
ST
12"
23.5
97
2270
3
SS
12"
4
24.0
5
4
ST
12"
19.9
104
1320
5
SS
12"
3
1
f4.0
SZ
10
12.0 85.5
SC
CLAYEY RAND WITH GRAVEL
Red, wet, medium dense
6
SS
12"
14
13.4
15.0 82.5
15
BOTTOM OF BORING
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS
Empire Laboratories
Incorporated
BORING STARTED 6-23-94
WL,
9 9.3' W.D.
8.6+ A.B.
BORING COMPLETED 6-23-94
RIG CME-55
FOREMAN DML
wL
Division of Termcon
ti�L
Water Checked 24 hrs. A.B.
APPROVED I1jR$
JOB N 20945132
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0
0
0
0
L_
LOG OF BORING No. 2
Page 1 of 1
CLIENT
ARCHITECT/ENGINEER
Tyco Oil Company
SITE Harmony Market 6th Filing
PROJECT
Fort Collins. Colorado
Proposed Convenience Store
SAMPLES
TESTS
i-
o
o
0
o
J
ao
LU
H
DESCRIPTION
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w
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3
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-1 u)
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F- O
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U G: LL
W LU LL
LD
Approx. Surface Elev.: 98.0 ft.
w
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FILL -Lean clay with
1
SS
12"
13
18.6
1.0 Sand and gravel 97.0
Brown, moist, very stiff
LEAN CLAY WITH SAND
CL
Brown, moist, very stiff
3.5 94.5
125
CL
2
ST
12"
18.1
109
4430
3
SS
12"
5
17.6
SANDY LEAN CLAY
Red/tan, moist, medium
5
7.5 90.5
SC
4
ST
12"
13.8
110
840
5
SS
12"
25
9.3
CLAYEY SAND WITH GRAVEL
Red, moist to wet, medium dense -
10
12.0 86.0
CL
SANDY LEAN CLAY
Tan/red, wet, medium
6
SS
12"
7
21.3
15.0 83.0
15
..
BOTTOM OF BORING
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS
Empire Laboratories
incorporated
Division of Tenacon
BORING STARTED 6-23-94
wL
UZ 8.8' W.D.
z 8.8' A.B.
BORING COMPLETED 6-23-94
wL
RIG CME-55
FOREMAN DML
WL
Water Checked 24 hrs. A.B.
APPROVED NRS
JOB # 20945132
I
0
I
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LOG OF BORING No. 3 Page 1 of 1
CLIENT
ARCHITECT/ENGINEER
Tyco Oil Company
SITE Harmony Market 6th Filing
PROJECT
Fort Collins, Colorado
Proposed Convenience Store
SAMPLES
TESTS
�
W
o7
z
W
D_
>-
LU
=>
O
U
X
U_
z
I (n
3
Ho
U) m
\
W
r
(n
H
z
H
(n
W
0
>- LL
o a.
W
Z 2
L1_ LD
zz
O W
U Q_ LL
N a
W
Qf
_j(o
J O
W W LL
W EL a-
.J
_
O_
ED
DESCRIPTION
Approx. Surface Elev.: 97.0 ft.
F-
U_
=
H
D_
M
m
E
(n
(n
U
"^"^"
0.5 6" TOPSOIL 96.5
LEAN CLAY WITH SAND
1
SS
12"
12
18.7
Brown, moist, stiff
CL
3.5 93.5
245
2
ST
12"
15.9
118
6820
CL
3
SS
12"
5
18.5
SANDY LEAN CLAY
5
Tan/red, moist to wet
Medium to very stiff
4
ST
12"
21.6
101
5460
5
SS
12"
4
26.1
SZ
10
12.0 85.0
Sc
CLAYEY SAND WITH GRAVEL
Red, wet, dense
6
SS
12"
39
22.1
15.0 82.0
15
BOTTOM OF BORING
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS
Empire Laboratories
Incorporated
Division of Tereacon
BORING STARTED 6-23-94
WL
Q 9.2' W.D.
s g.8, A.B.
BORING COMPLETED 6-23-94
WL
Ww
RIG CME-55
FOREMAN DML
Water Checked 24 hrs. A.B.
APPROVED NRS
JOB # 20945132