HomeMy WebLinkAboutBMC WEST PUD - PRELIMINARY - 1-96 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORT11
Geotechnical Engineering Exploration Terracon
Proposed Warehouse-BMC West
Terracon Project No. 20955203
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.
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Geotechnical Engineering Exploration Terracon
Proposed Warehouse-BMC West
Terracon Project No. 20955203
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load distribution. It is suggested that clean, graded gravel compacted to 75
percent of Relative Density ASTM D4253 be used as bedding. Where utilities
are excavated below groundwater, temporary dewatering will be required during
excavation, pipe placement and backfilling operations for proper construction.
Utility trenches should be excavated on safe and stable slopes in accordance
with OSHA regulations as discussed above. Backfill should consist of the on -
site soils or existing bedrock. If bedrock is used, all plus 6-inch material should
be removed from it prior to its use. The pipe backfill should be compacted to
a minimum of 95 percent of Standard Proctor Density ASTM D698.
• Corrosion Protection: Results of soluble sulfate testing indicate that ASTM Type
1-II Portland cement is suitable for all concrete on or 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 eventthat
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.
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 confirm 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
J requirements have been met. It would be logical for Terracon Consultants Western,
Inc. to provide these additional services for continuing from design through construction
and to determine the consistency of field conditions with those data used in our
I 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 re-evaluate the recommendations of this report.
L Our professional services were performed using that degree of care and skill ordinarily
—1 exercised, under similar circumstances, by reputable geotechnical engineers practicing
LJ 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
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Geotechnical Engineering Exploration Terracon
Proposed Warehouse-BMC West
Terracon Project No. 20955203
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 5 percent for at least 10 feet from
perimeter walls. Backfill against footings, exterior walls and in utility and
sprinkler line trenches should be well 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.
• Subsurface Drainage: Free -draining, granular soils containing less than five
percent fines (by weight) passing a No. 200 sieve should be placed adjacent to
walls which retain earth. A drainage system consisting of either weep holes or
perforated drain lines (placed near the base of the wall) should be used to
intercept and discharge water which would tend to saturate the backfill. Where
used, drain lines should be embedded in a uniformly graded filter material and
provided with adequate clean -outs for periodic maintenance. An impervious soil
should be used in the upper layer of backfill to reduce the potential for water
infiltration.
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:
L,J • minimizing moisture increases in the backfill
• controlling moisture -density during placement of backfill
• using designs which allow vertical movement between the
,y exterior features and adjoining structural elements
• placing effective control joints on relatively close centers
-� • allowing vertical movements in utility connections
I
• Underground Utility Systems: All piping should be adequately bedded for proper
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Geotechnical Engineering Exploration
Proposed Warehouse-BMC West
Terracon Project No. 20955203
Material
Terracon
Minimum Percent
(ASTM D698)
Subgrade soils beneath fill areas ..................... 95
�. On -site soils or approved imported fill:
Beneath foundations ......................... 98
Beneath slabs ............................. 95
Beneath pavements 95
Utilities ....................................... 95
Aggregate base (beneath slabs) ...................... 95
Miscellaneous backfill ............................. 90
5. Granular soils should be compacted within a moisture content range of 3
percent below to 3 percent above optimum unless modified by the project
geotechnical engineer.
6. Clay soils placed around or beneath foundations should be compacted within
a moisture content range of optimum to 2 percent above optimum. Clay soils
placed beneath pavement should be compacted within a moisture content
range of 2 percent below to 2 percent above optimum.
• Shrinkage: For balancing grading plans, estimated shrink or swell of soils and
bedrock when used as compacted fill following recommendations in this report are
as follows:
Material
Estimated Shrink(-) Swell W
Based on ASTM D698
On -site soils:
Clay ..................................... .15 to -20%
Sand and Gravel .............................. -5 to -10%
Drainage:
• Surface Drainage:
1. Positive drainage should be provided during construction and maintained
throughout the life of the proposed facility. Infiltration of water into
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�J Geotechnical Engineering Exploration Terracon
�.I Proposed Warehouse-BMC West
Terracon Project No. 20955203
l • 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 retaining walls.
3. Frozen soils should not be used as fill or backfill.
4. Imported soils (if required) should conform to the following or be approved
by the Project Geotechnical Engineer:
Percent finer by weight
Gradation (ASTM C136)
6"......................................... 100
3"....................................... 70-100
No. 4 Sieve .................................. 50-80
No. 200 Sieve .. ......................... 30 (max)
• Liquid Limit ...... 30 (max)
• Plasticity Index ......................... 10 (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. No fill should be placed over frozen ground.
3. Materials should be compacted to the following:
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Geotechnical Engineering Exploration Terracon
Proposed Warehouse-BMC West
Terracon Project No. 20955203
minimum depth of 8 inches, conditioned to near optimum moisture content,
and compacted.
6. The finished subgrade below slabs should be placed a
minimum of 3 feet above existing groundwater.
• 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.
3. On -site clay soils in proposed pavement areas may pump or become unstable
or unworkable at high water contents. Workability may be improved by
scarifying and drying. Overexcavation of wet zones and replacement with
granular materials may be necessary. Lightweight excavation equipment may
be required to reduce subgrade pumping. Minimizing construction traffic on -
site is recommended.
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.
Proof -rolling of the subgrade may be required to determine stability prior to
Jpaving.
8. Due to the shallow depth to groundwater, pavement subgrade stabilization
is anticipated. With properly designed stabilization, reductions in the
pavement section may be possible.
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Geotechnical Engineering Exploration Terracon
Proposed Warehouse-BMC West
Terracon Project No. 20955203
�JI 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.
Earthwork:
• Site Clearing and Subgrade Preparation:
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. All existing fill should be removed from below slab and/or footing areas and
the upper two feet of the existing fill should be removed from below all paved
areas. 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 backf ill placement.
I ] 3. Stripped materials consisting of vegetation and organic materials should be
wasted from the site or used to revegetate exposed slopes after completion
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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. The site should be initially graded to create a relatively level surface to
receive fill, and to provide for a relatively uniform thickness of fill beneath
proposed building structures.
5. All exposed areas which will receive fill, floor slabs and/or pavement, once
properly cleared and benched where necessary, should be scarified to a
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Geotechnical Engineering Exploration
Proposed Warehouse-BMC West
Terracon Project No. 20955203
Terracon
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.
The performance of all pavements can be enhanced by minimizing excess moisture which
d can reach the subgrade soils. The following recommendations should be considered at
d 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;
J• 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.
JPreventative maintenance should be planned and provided for 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.
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Geotechnical Engineering Exploration
Proposed Warehouse-BMC West
Terracon Project No. 20955203
Terracon
which meets strict specifications for quality and gradation. Use of materials meeting
Colorado Department of Transportation (CDOT) Class 5 or 6 specifications is recommended
for base course.
Aggregate base course and select subbase should be placed in lifts not exceeding six inches
and should be compacted to a minimum of 95% Standard Proctor Density (ASTM D698).
Asphalt concrete and/or 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 and/or asphalt concrete should conform to approved mix designs
stating the Marshall or Hveem properties, optimum asphalt content, job mix formula and
recommended mixing and placing temperatures. Aggregate used in plant -mixed bituminous
base course and/or asphalt concrete should meet particular gradations. Material meeting
Colorado Department of Transportation Grading C or CX specification is recommended for
asphalt concrete. Aggregate meeting Colorado Department of Transportation Grading G or
C specifications is recommended for plant -mixed bituminous base course. Mix designs
should be submitted prior to construction to verify their adequacy. Asphalt material should
be placed in maximum 3-inch lifts and should be compacted to a minimum of 95% of
Hveem density (ASTM D1560).
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 psi minimum
• Strength Requirements ............................ ASTM C94
• Minimum Cement Content ..................... 6.5 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 the time the water is added to the mix. Other specifications outlined by the
Colorado Department of Transportation should be followed.
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Geotechnical Engineering Exploration Terracon
Proposed Warehouse-BMC West
y Terracon Project No. 20955203
JFor structural design of concrete slabs -on -grade, a modulus of subgrade reaction of 100
pounds per cubic inch (pci) may be used for floors supported on existing or engineered fill
consisting of on -site soils.
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 12 as the
criterion for pavement design, the following minimum pavement thicknesses are
recommended:
Recommended Pauerrient Section Thjdkness (inches
gig
Ater
native
Asphalt
Aggregate i
Select
PPrit Mixed ,
Portland
Concrete
Base
Subbase
Bituminous :
Cement
Total
Surface
Course
...
Concrete
A
3
5
8
Automobile
B
2
3
5
Parking
C
5
A
3
10
13
Main
Traffic
B
2
4 1 /2
6 1 /2
Corridors
C
6
6
Each alternative should be investigated with respect to current material availability and
economic conditions.
The pavement sections presented herein are based on design parameters selected by
Terracon based on experience with similar projects and soils conditions. Design parameters
such as design life, terminal serviceability index, modulus of rupture of concrete and
inherent reliability may vary with specific project. Variation of these parameters may
change the thickness of the pavement sections presented. Terracon is prepared to discuss
the details of these parameters and their effects on pavement design and reevaluate
pavement design as appropriate.
Aggregate base course (if used on the site) should consist of a blend of sand and gravel
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Geotechnical Engineering Exploration Terracon
Proposed Warehouse-BMC West
Terracon Project No. 20955203
Fill against grade beams and retaining walls should be compacted to densities specified in
"Earthwork". Medium to high plasticity clay soils should not be used as backfill against
retaining walls. 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.
Floor Slab Design and Construction: Non -expansive, or only low expansive 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 increase 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. All existing fill should be removed from below
slabs on grade.
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. Joints should be a minimum of 25% of slab thickness plus
A inch.
• Interior trench backfill placed 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 in
warehouse areas a minimum 6 inches of aggregate base course should be
placed below interior slabs.
• 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.
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Geotechnical Engineering Exploration
Proposed Warehouse-BMC West
Terracon Project No. 20955203
Terracon
recompaction. Any additional fill should be placed prior to foundation construction to allow
for some consolidation of the subsoils from the added weight of the new fill.
Exterior footings should be placed a minimum of 30 inches below finished grade for frost
protection. Finished grade is the lowest adjacent grade for perimeter footings.
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 settlement resulting from the assumed structural loads
is estimated to be on the order of 3/4 inch. Proper drainage should be provided in the final
design and during construction to reduce the settlement potential.
Lateral Earth Pressures: For soils above any free water surface, recommended equivalent
fluid pressures for unrestrained foundation elements are:
• Active:
Cohesive soil backfill (site clay) ....................... 40 psf/ft
Cohesionless soil backfill (on -site sand or gravel) ............ 35 psf/ft
• Passive:
Cohesive soil backfill (clay) ......................... 360 psf/ft
Cohesionless soil backfill (on -site sand or gravel) .......... 450 psf/ft
• Coefficient of base friction sand or gravel .................... .30
• Adhesion at base of footing (clay) ...................... 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 or gravel) 55 psf/ft
The lateral earth pressures herein are not applicable for submerged soils. Additional
recommendations may be necessary if such conditions are to be included in the design.
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Geotechnical Engineering Exploration Terracon
Proposed Warehouse-BMC West
Terracon Project No. 20955203
J Based upon review of U.S. Geological Survey maps ('Hillier, et al, 1983), regional
groundwater is expected to be encountered in unconsolidated alluvial deposits on the site,
at depths ranging from 0 to 5 feet below the existing ground surface.
CONCLUSIONS AND RECOMMENDATIONS
Geotechnical Considerations: The site appears suitable for the proposed construction.
Existing fill and the shallow depth to groundwater encountered at the site will require
particular attention in the design and construction.
The following foundation systems were evaluated for use on the site:
• spread footings bearing on undisturbed soils; and,
• spread footings bearing on engineered fill.
Design criteria for alternative foundation systems is subsequently outlineda Use of the
alternative foundation systems outlined in this report should be determined for individual
residential structures on the basis of supplemental geotechnical exploration of each lot prior
to construction.
Slab -on -grade construction is considered acceptable for use provided that design and
Jconstruction recommendations are followed. Existing fill should be removed from below
slabs on grade and the upper two feet of fill should be removed from below paved areas.
Foundation Systems: Due to the presence of non- to low -swelling soils on the site, spread
footing foundations bearing upon undisturbed subsoils or engineered fill are recommended
for support for the proposed structure. Footings should not be placed on existing fill or on
structural fill placed on existing fill. The footings may be designed for a maximum bearing
pressure of 1500 psf. The design bearing pressure applies to dead loads plus design live
1 load conditions. The design bearing pressure may be increased by one-third when
considering total loads that include wind or seismic conditions.
Existing fill on the site should not be used for support of foundations without removal and
'Hillier, 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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Geotechnical Engineering Exploration
Proposed Warehouse-BMC West
Terracon Project No. 20955203
and Recent Age.
Terracon
Soil and Bedrock Conditions: The following describes the characteristics of the primary soil
strata in order of increasing depths:
• Fill material: The area tested is overlain by a 1.0 to 3.5 foot
layer of fill material. The fill consists of a mixture of sandy
lean clay with gravel. The fill is moist and stiff to very stiff.
• Sandy Lean Clay: The clay stratum was encountered in
borings 4, 6 and 7 below the fill and extends to the sand or
gravel below. The clay is moist and stiff to very stiff in
consistency.
• Silty Sand: A layer of silty sand was encountered in borings
1 and 3 at depths of 2 to 3.5 feet and extends to the gravel
layer below. The silty sand is loose and moist to wet.
• Well graded Gravel with Sand and Cobbles: The gravel layer
was encountered in all borings at depths of 1.5 to 76.5 feet
below the surface. The gravel contains varying amounts of
sand and cobbles ranging in size up to 8 inches in diameter.
The gravel is moist to wet and medium dense to extremely
dense.
Field and Laboratory Test Results: Field test results indicate that the clay soils are
moderately plastic and exhibit low bearing characteristics. The granular soils are non -
expansive and exhibit moderate to high bearing characteristics.
Groundwater Conditions: Groundwater was encountered in all borings at approximate
Jdepths of 4 to 6 feet in the test borings at the time of field exploration. When checked 2
days after drilling, groundwater was measured at approximate depths of 3 to 5 1 /2 feet
J below the surface. 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.
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Geotechnical Engineering Exploration Terracon
Proposed Warehouse-BMC West
Terracon Project No. 20955203
Selected soil samples were tested for the following engineering properties:
• Water content • Plasticity Index
• Dry density • Water soluble sulfate content
• Consolidation
• Compressive strength
JExpansion
J The significance and purpose of each laboratory test is described in Appendix C. Laboratory
test results are presented in Appendix B, and were used for the geotechnical engineering
analyses, and the development of foundation and earthwork recommendations. All
J laboratory tests were performed in general accordance with the applicable ASTM, local or
other accepted standards.
JSITE CONDITIONS
This is a vacant area vegetated with weeds and grasses. Several small trees are located
along Timberline Road. The site is relatively flat and has generally poor surface drainage.
The property is bordered on the north by a Western Mobile Northern Gravel Pit, to the east
by Spring Creek, to the south by the existing BMC West facility and to the west by
Timberline Road which is gravel surfaced. A chainlink fence borders the south edge of the
site. Piles of fill were observed on the site. Fill piles include soil, concrete, tree stumps,
logs, metal, plastic and other unsuitable materials.
SUBSURFACE CONDITIONS
Geology:
The proposed 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. It is anticipated the bedrock underlies the site at
depths of 20 to 25 feet. The bedrock is overlain by alluvial gravels and clays of Pleistocene
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Geotechnical Engineering Exploration Terracon
Proposed Warehouse-BMC West
Terracon Project No. 20956203
Field Exploration: A total of 7 test borings were drilled on December 8, 1995 to depths of
10 to 15 feet at the locations shown on the Site Plan, Figure 1. Five borings were drilled
within the proposed building location, and 6 borings were drilled in the area of proposed
J pavements. All borings were advanced with a truck -mounted drilling rig, utilizing 4-inch
diameter solid stem auger.
J The. borings were located in the field by pacing from existing site features. Elevations were
taken at each boring location by measurements with a hand level from the temporary bench
J 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 by 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
Jresistance value is a useful index to the consistency, relative density or hardness of the
materials encountered.
JGroundwater measurements were made in each boring at the time of site exploration, and
2 to 6 days 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 and an applicable
laboratory testing program was formulated to determine engineering properties of the
subsurface materials. Boring logs were prepared and are presented in Appendix A.
2
GEOTECHNICAL ENGINEERING REPORT
PROPOSED WAREHOUSE-BMC-WEST
TIMBERLINE ROAD
FORT COLLINS, COLORADO
Terracon Project No. 20955203
January 2, 1996
IINTRODUCTION
JThis report contains the results of our geotechnical engineering exploration for the proposed
warehouse addition to the BMC West facility to be located on the extension to Timberline
Road north of East Prospect Road in east Fort Collins, Colorado. The site is located in the
Southwest Quarter of Section 17, Township 7 North, Range 68 West of the 6th Principal
Meridian.
The purpose of these services is to provide information and geotechnical engineering
recommendations relative to:
• subsurface soil and bedrock conditions
• groundwater conditions
• foundation design and construction
• lateral earth pressures
l • floor slab design and construction
J • pavement design and construction
• earthwork
• drainage
The conclusions and recommendations contained in this report are based upon the results
of field and laboratory testing, engineering analyses, and experience with similar soil
conditions, structures and our understanding of the proposed project.
PROPOSED CONSTRUCTION
The proposed construction as we understand it is to construct a 150 x 270 foot dock
height warehouse. The structure will be surrounded by paved parking, driveway and loading
areas to the south and west.
SITE EXPLORATION
The scope of the services performed for this project included site reconnaissance by an
1 engineering geologist, a subsurface exploration program, laboratory testing and engineering
analysis.
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Geotechnical Engineering Exploration
Proposed Warehouse-BMC West
Terracon Project No. 20955203
TABLE OF CONTENTS (Cont'd)
Figure No.
APPENDIX A
SitePlan ................................................. 1
Logs of Borings ..................................... Al thru A7
APPENDIX B
Swell -Consolidation Test ................................ 61 thru B4
APPENDIX C: GENERAL NOTES
Drilling & Exploration ....................................... C1
Unified Soil Classification .................................... C2
Bedrock Classification, Sedimentary Bedrock ....................... C3
Bedrock Classification, Igneous Bedrock .......................... C3
Bedrock Classification, Metamorphic Bedrock ...................... C3
Laboratory Testing, Significance and Purpose ...................... C4
Report Terminology ...................... C5
APPENDIX D
Recommended Preventative Maintenance -Asphalt Concrete Pavements .... D1
Recommended Preventative Maintenance -Jointed Concrete Pavements .... D2
Geotechnical Engineering Exploration
Proposed Warehouse-BMC West
Terracon Project No. 20955203
TABLE OF CONTENTS
Page No.
Letter of Transmittal ...............................................
INTRODUCTION ................................................ 1
PROPOSED CONSTRUCTION ....................................... 1
1
SITE EXPLORATION .............................................
2
1 Field Exploration ..........................................
2
J Laboratory Testing
3
1 SITE CONDITIONS ...............................................
CLIRCI IRFACF CONDITIONS ....................................... 3
rPnlnnV---'...................................... 3
Soil and Bedrock Conditions .................................. 4
Field and Laboratory Test Results .:............................. 4
Groundwater Conditions ................................. .. 4
CONCLUSIONS AND RECOMMENDATIONS ............................ 5
Geotechnical Considerations .................................. 5
Foundation Systems ........................................ 5
Lateral Earth Pressures ...................................... 6
Floor Slab Design and Construction ............................. 7
Earthwork ...................
11
Site Clearing and Subgrade Preparation ...................... 11
Excavation .......... 12
Fill Materials ........................................ 12
Placement and Compaction .............................. 13
Shrinkage 14
Drainage................................................ 14
Surface Drainage ..................................... 14
Subsurface Drainage ................................... 15
Additional Design and Construction Considerations .................. 15
Exterior Slab Design and Construction ...................... 15
Underground Utility Systems ............................. 15
Corrosion Protection ................................... 16
GENERAL COMMENTS ........................................... 16
GEOTECHNICAL ENGINEERING REPORT
PROPOSED WAREHOUSE-BMC WEST
TIMBERLINE ROAD
FORT COLLINS, COLORADO
TERRACON PROJECT NO. 20955203
January 3, 1996
Prepared for.
BMC-West
1007 Ogden Court
Fort Collins, Colorado 80526
Attn: Jimmy Pask
lrerracon
GEOTECHNICAL ENGINEERING REPORT
PROPOSED WAREHOUSE-BMC WEST
TIMBERLINE ROAD
FORT COLLINS, COLORADO
TERRACON PROJECT NO. 20955203
January 3, 1996
Irerracon