HomeMy WebLinkAboutOAKRIDGE CROSSING (AFFORDABLE SENIOR HOUSING) - PDP - PDP160009 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTGeotechnical Engineering Report
Oakridge Crossing
Southeast of Oakridge Drive and McMurry Avenue
Fort Collins, Colorado
March 10, 2016
Terracon Project No. 20165021
Prepared for:
McDermott Properties
Centennial, Colorado
Prepared by:
Terracon Consultants, Inc.
Fort Collins, Colorado
TABLE OF CONTENTS
Page
EXECUTIVE SUMMARY ............................................................................................................ i
1.0 INTRODUCTION .............................................................................................................1
2.0 PROJECT INFORMATION .............................................................................................1
3.0 SUBSURFACE CONDITIONS ........................................................................................2
3.1 Typical Subsurface Profile ...................................................................................2
3.2 Laboratory Testing ...............................................................................................3
3.3 Corrosion Protection (Water-Soluble Sulfates) .....................................................3
3.4 Groundwater ........................................................................................................3
4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION ......................................4
4.1 Geotechnical Considerations ...............................................................................4
4.1.1 Potentially Unstable Clay Subgrade Soils .................................................4
4.1.2 Groundwater .............................................................................................4
4.1.3 Expansive Soils ........................................................................................4
4.1.4 Foundation Recommendations .................................................................5
4.2 Earthwork.............................................................................................................5
4.2.1 Site Preparation ........................................................................................5
4.2.2 Excavation ................................................................................................5
4.2.3 Subgrade Preparation ...............................................................................6
4.2.4 Fill Materials and Placement ......................................................................7
4.2.5 Compaction Requirements ........................................................................7
4.2.6 Utility Trench Backfill ................................................................................8
4.2.7 Grading and Drainage ...............................................................................8
4.2.8 Exterior Slab Design and Construction .....................................................9
4.3 Foundations .........................................................................................................9
4.3.3 Post-Tensioned Slabs – Construction Considerations ............................12
4.3.4 Spread Footings - Design Recommendations .........................................12
4.3.5 Spread Footings - Construction Considerations ......................................14
4.3.6 Overexcavation Beneath Footings ..........................................................14
4.4 Seismic Considerations......................................................................................15
4.5 Lateral Earth Pressures ...........................................................................................15
4.6 Pavements .........................................................................................................17
4.6.1 Pavements – Subgrade Preparation .......................................................17
4.6.2 Pavements – Design Recommendations ................................................17
4.6.3 Pavements – Construction Considerations .............................................20
4.6.4 Pavements – Maintenance .....................................................................20
5.0 GENERAL COMMENTS ...............................................................................................20
TABLE OF CONTENTS (continued)
Appendix A – FIELD EXPLORATION
Exhibit A-1 Site Location Map
Exhibit A-2 Exploration Plan
Exhibit A-3 Field Exploration Description
Exhibits A-4 to A-11 Boring Logs
Appendix B – LABORATORY TESTING
Exhibit B-1 Laboratory Testing Description
Exhibit B-2 Atterberg Limits Test Results
Exhibits B-3 to B-7 Grain-size Distribution Test Results
Exhibits B-8 to B-9 Swell-consolidation Test Results
Exhibits B-10 to B-11 Unconfined Compression Test Results
Exhibit B-12 Water-soluble Sulfate Test Results
Appendix C – SUPPORTING DOCUMENTS
Exhibit C-1 General Notes
Exhibit C-2 Unified Soil Classification System
Exhibit C-3 Description of Rock Properties
Exhibit C-4 Laboratory Test Significance and Purpose
Exhibits C-5 and C-6 Report Terminology
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March 10, 2016 ■ Terracon Project No. 20165021
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EXECUTIVE SUMMARY
A geotechnical investigation has been performed for the proposed Oakridge Crossing to be
constructed southeast of Oakridge Drive and McMurry Avenue in Fort Collins, Colorado. A total of
eight (8) exploratory borings, presented as Exhibits A-4 through A-11 were completed to depths of
approximately 10 to 25 feet below existing site grades. This report specifically addresses the
recommendations for the proposed structure. Borings performed in these areas are for informational
purposes and will be utilized by others.
Based on the information obtained from our subsurface exploration, the site can be developed for
the proposed project. However, the following geotechnical considerations were identified and will
need to be considered:
n The proposed buildings may be supported on a post-tensioned slab foundation bearing
on the stiff to very stiff native soil or on newly placed engineered fill.
n The amount of movement of foundations, exterior concrete flatwork, pavements, etc. will be
related to the wetting of underlying supporting soils. Therefore, it is imperative the
recommendations discussed in the 4.2.7 Grading and Drainage section of this report be
followed to reduce potential movement.
n The 2012 International Building Code, Table 1613.5.2 IBC seismic site classification for this
site is D.
n Close monitoring of the construction operations discussed herein will be critical in achieving
the design subgrade support. We therefore recommend that Terracon be retained to
monitor this portion of the work.
This summary should be used in conjunction with the entire report for design purposes. It should
be recognized that details were not included or fully developed in this section, and the report must
be read in its entirety for a comprehensive understanding of the items contained herein. The section
titled GENERAL COMMENTS should be read for an understanding of the report limitations.
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GEOTECHNICAL ENGINEERING REPORT
Oakridge Crossing
Southeast of Oakridge Drive and McMurry Avenue
Fort Collins, Colorado
Terracon Project No. 20165021
March 10, 2016
1.0 INTRODUCTION
This report presents the results of our geotechnical engineering services performed for the
proposed Oakridge Crossing Project to be located southeast of the intersection between Oakridge
Drive and McMurry Avenue in Fort Collins, Colorado (Exhibit A-1). The purpose of these services
is to provide information and geotechnical engineering recommendations relative to:
n subsurface soil and bedrock conditions n foundation design and construction
n groundwater conditions n floor system design and construction
n grading and drainage n pavement construction
n lateral earth pressures n earthwork
n seismic considerations
Our geotechnical engineering scope of work for this project included the advancement of eight
test borings to depths ranging from approximately 10 to 25 feet below existing site grades,
laboratory testing for soil engineering properties and engineering analyses to provide foundation,
floor system and pavement design and construction recommendations.
Logs of the borings along with an Exploration Plan (Exhibit A-2) are included in Appendix A. The
results of the laboratory testing performed on soil and bedrock samples obtained from the site
during the field exploration are included in Appendix B.
2.0 PROJECT INFORMATION
2.1 Site Location
Item Description
Location The site is located southeast of the intersection of Oakridge Drive and
McMurry Avenue in Fort Collins, Colorado.
Existing improvements Aerial photography suggests the site is currently vacant land surrounded by
commercial and retail properties.
Current ground cover The ground surface appears to be covered with native grasses and weeds.
Existing topography The site appears to be relatively flat.
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2.2 Project Description
Item Description
Proposed construction
We understand the proposed project includes a new, 3-story, mixed-use
senior apartments and approximately 5,000 square feet of ground floor
commercial office space. The apartment building will consist of 110 units, a
“great room”, fire place, library, game room, physical fitness center,
community kitchen, storage units, and a computer area. The project will also
include access drives and 103 parking spaces.
Building construction
We anticipate the apartment building will be constructed of steel, wood,
and/or masonry. We understand the design team is considering post-
tensioned slabs for the foundation system and wood exterior framing.
Maximum loads
Columns: 20 to 40 kips (assumed)
Walls: 2 to 5 klf (assumed)
Slabs: 150 psf max (assumed)
Cut and fill slopes
We anticipate minor cuts and fills on the order of 5 feet or less will be
required for the construction at this site with deeper cuts and fills up to about
8 feet being required for the installation of new utilities.
Below-grade areas No below-grade areas are planned for this site.
3.0 SUBSURFACE CONDITIONS
3.1 Typical Subsurface Profile
Specific conditions encountered at each boring location are indicated on the individual boring logs
included in Appendix A. Stratification boundaries on the boring logs represent the approximate
location of changes in soil types; in-situ, the transition between materials may be gradual. Based
on the results of the borings, subsurface conditions on the project site can be generalized as
follows:
Material Description Approximate Depth to
Bottom of Stratum (feet) Consistency/Density/Hardness
Lean clay with varying amounts of
sand and gravel
About 5 to 19 feet below
existing site grades.
Medium stiff to stiff
Sand with varying amounts of clay
and gravel
About 10 to 24 feet below
existing site grades. Loose to dense
Interbedded Sandstone and
Claystone bedrock
To the maximum depth of
exploration of about 25 feet. Weathered to very hard
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3.2 Laboratory Testing
Representative soil samples were selected for swell-consolidation testing and exhibited 0.8 swell
to 2.4 percent compression when wetted. Two samples of clay soils exhibited unconfined
compressive strengths of approximately 740 and 3,200 pounds per square foot (psf). Samples of
site soils and bedrock selected for plasticity testing exhibited low to high plasticity with liquid limits
ranging from non-plastic to 51 and plasticity indices ranging from 9 to 28. Laboratory test results
are presented in Appendix B.
3.3 Corrosion Protection (Water-Soluble Sulfates)
Results of water-soluble sulfate testing indicate that ASTM Type II, portland cement should be
specified for all project concrete on and below grade. Foundation concrete should be designed
for moderate sulfate exposure in accordance with the provisions of the ACI Design Manual,
Section 318, Chapter 4.
3.4 Groundwater
The boreholes were observed while drilling and after completion for the presence and level of
groundwater. In addition, delayed water levels were also obtained in some borings. The water levels
observed in the boreholes are noted on the attached boring logs, and are summarized below.
Boring Number Depth to groundwater
while drilling, ft.
Depth to groundwater
5 days after drilling, ft.
Elevation of
groundwater 8 days
after drilling, ft.
1 9 9.9 90.3
2 11 8.9 89.9
3 12 9.9 89.6
4 11 10.4 89.6
5 Not encountered 11.0 90.0
P1 Not encountered Not encountered Not encountered
P2 Not encountered Not encountered Not encountered
P3 Not encountered Not encountered Not encountered
These observations represent groundwater conditions at the time of the field exploration, 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, and other factors.
Groundwater level fluctuations occur due to seasonal variations amount of rainfall, runoff and
other factors not evident at the time the borings was/were performed. Therefore, groundwater
levels during construction or at other times in the life of the structure(s) may be higher or lower
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than the levels indicated on the boring logs. The possibility of groundwater level fluctuations
should be considered when developing the design and construction plans for the project.
Fluctuations in groundwater levels can best be determined by implementation of a groundwater
monitoring plan. Such a plan would include installation of groundwater piezometers, and periodic
measurement of groundwater levels over a sufficient period of time.
4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION
4.1 Geotechnical Considerations
Based on subsurface conditions encountered in the borings, the site appears suitable for the
proposed construction from a geotechnical point of view provided certain precautions and design
and construction recommendations described in this report are followed. We have identified
geotechnical conditions that could impact design and construction of the proposed structures,
pavements, and other site improvements.
4.1.1 Potentially Unstable Clay Subgrade Soils
Based on our experience in the area, the data suggests that portions of the upper lean clay soils
may be at moisture contents that could result in unstable conditions below the proposed
foundations, exterior concrete flatwork, and pavements. Exposure to significant precipitation
events, snowmelt, or repeated rubber tire traffic could also develop unstable conditions. We
believe some subgrade areas below the site will require stabilization. It may be prudent to include
a separate bid item for subgrade stabilization.
4.1.2 Groundwater
As previously stated, groundwater was measured at depths ranging from about 8.9 to 11.0 feet
below existing site grades. Terracon recommends maintaining a separation of at least 3 feet
between the bottom of proposed below-grade foundations and measured groundwater levels.
Groundwater levels below this site may fluctuate seasonally as well as during periods of drought
and prolonged precipitation.
4.1.3 Expansive Soils
Laboratory testing indicates the native clay soils exhibited low expansive potential at the samples
in-situ moisture content. However, it is our opinion these materials will exhibit a higher expansive
potential if the clays undergo a significant loss of moisture.
This report provides recommendations to help mitigate the effects of soil shrinkage and
expansion. However, even if these procedures are followed, some movement and cracking in
the structures, pavements, and flatwork should be anticipated. The severity of cracking and other
damage such as uneven floor slabs will probably increase if any modification of the site results in
excessive wetting or drying of the expansive clays. Eliminating the risk of movement and distress
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is generally not feasible, but it may be possible to further reduce the risk of movement if
significantly more expensive measures are used during construction. It is imperative the
recommendations described in section 4.2.7 Grading and Drainage of this report be followed to
reduce movement.
4.1.4 Foundation Recommendations
The proposed building may be supported on a post-tensioned slab system bearing on properly
prepared on-site soils or properly placed imported fill.
4.2 Earthwork
The following presents recommendations for site preparation, excavation, subgrade preparation
and placement of engineered fills on the project. All earthwork on the project should be observed
and evaluated by Terracon on a full-time basis. The evaluation of earthwork should include
observation of over-excavation operations, testing of engineered fills, subgrade preparation,
subgrade stabilization, and other geotechnical conditions exposed during the construction of the
project.
4.2.1 Site Preparation
Prior to placing any fill, strip and remove existing vegetation and any other deleterious materials
from the proposed construction areas.
Stripped organic materials should be wasted from the site or used to re-vegetate landscaped areas
after completion of grading operations. Prior to the placement of fills, the site should be graded to
create a relatively level surface to receive fill, and to provide for a relatively uniform thickness of fill
beneath proposed structures.
If fill is placed in areas of the site where existing slopes are steeper than 5:1 (horizontal:vertical),
the area should be benched to reduce the potential for slippage between existing slopes and fills.
Benches should be wide enough to accommodate compaction and earth moving equipment, and
to allow placement of horizontal lifts of fill.
4.2.2 Excavation
It is anticipated that excavations for the proposed construction can be accomplished with
conventional earthmoving equipment.
The excavated soils can vary significantly across the site as their 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.
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Although evidence of fills or underground facilities such as septic tanks, vaults, basements, and
utilities was not observed during the site reconnaissance, such features could be encountered
during construction. If unexpected fills or underground facilities are encountered, such features
should be removed and the excavation thoroughly cleaned prior to backfill placement and/or
construction.
Any over-excavation that extends below the bottom of foundation elevation should extend laterally
beyond all edges of the foundations at least 8 inches per foot of over-excavation depth below the
foundation base elevation. The over-excavation should be backfilled to the foundation base
elevation in accordance with the recommendations presented in this report.
Depending upon depth of excavation and seasonal conditions, surface water infiltration and/or
groundwater may be encountered in excavations on the site. It is anticipated that pumping from
sumps may be utilized to control water within excavations.
The subgrade soil conditions should be evaluated during the excavation process and the stability
of the soils determined at that time by the contractors’ Competent Person. Slope inclinations flatter
than the OSHA maximum values may have to be used. 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.
As a safety measure, it is recommended that all vehicles and soil piles be kept a minimum lateral
distance from the crest of the slope equal to the slope height. The exposed slope face should be
protected against the elements
4.2.3 Subgrade Preparation
After the deleterious materials have been removed from the construction areas, the top 8 inches
of the exposed ground surface should be scarified, moisture conditioned, and recompacted to at
least 95 percent of the maximum dry unit weight as determined by ASTM D698 before any new
fill or foundation or pavement is placed.
If pockets of soft, loose, or otherwise unsuitable materials are encountered at the bottom of the
foundation excavations and it is inconvenient to lower the foundations, the proposed foundation
elevations may be reestablished by over-excavating the unsuitable soils and backfilling with
compacted engineered fill or lean concrete.
After the bottom of the excavation has been compacted, engineered fill can be placed to bring the
building pad and pavement subgrade to the desired grade. Engineered fill should be placed in
accordance with the recommendations presented in subsequent sections of this report.
The stability of the subgrade may be affected by precipitation, repetitive construction traffic or
other factors. If unstable conditions develop, workability may be improved by scarifying and
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drying. Alternatively, over-excavation of wet zones and replacement with granular materials may
be used, or crushed gravel and/or rock can be tracked or “crowded” into the unstable surface soil
until a stable working surface is attained. Lightweight excavation equipment may also be used to
reduce subgrade pumping.
4.2.4 Fill Materials and Placement
The on-site soils or approved granular and low plasticity cohesive imported materials may be used
as fill material. The soil removed from this site that is free of organic or objectionable materials,
as defined by a field technician who is qualified in soil material identification and compaction
procedures, can be re-used as fill for the building pad and pavement subgrade. It should be noted
that on-site clayey soils may require reworking to adjust the moisture content to meet the
compaction criteria.
Imported soils (if required) should meet the following material property requirements:
Gradation Percent finer by weight (ASTM C136)
4” 100
3” 70-100
No. 4 Sieve 50-100
No. 200 Sieve 15-50
Soil Properties Values
Liquid Limit 35 (max.)
Plastic Limit 6 (max.)
Maximum Expansive Potential (%) Non-expansive1
1. Measured on a sample compacted to approximately 95 percent of the maximum dry unit weight as
determined by ASTM D698 at optimum moisture content. The sample is confined under a 100 psf
surcharge and submerged.
4.2.5 Compaction Requirements
Engineered fill should be placed and compacted in horizontal lifts, using equipment and
procedures that will produce recommended moisture contents and densities throughout the lift.
Item Description
Fill lift Thickness
9 inches or less in loose thickness when heavy, self-
propelled compaction equipment is used
4 to 6 inches in loose thickness when hand-guided
equipment (i.e. jumping jack or plate compactor) is used
Minimum compaction requirements 95 percent of the maximum dry unit weight as determined
by ASTM D698
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Item Description
Moisture content cohesive soil (clay) -1 to +3 % of the optimum moisture content
Moisture content cohesionless soil
(sand) -3 to +3 % of the optimum moisture content
1. We recommend engineered fill be tested for moisture content and compaction during placement.
Should the results of the in-place density tests indicate the specified moisture or compaction limits
have not been met, the area represented by the test should be reworked and retested as required
until the specified moisture and compaction requirements are achieved.
2. Specifically, moisture levels should be maintained low enough to allow for satisfactory compaction to
be achieved without the fill material pumping when proofrolled.
3. Moisture conditioned clay materials should not be allowed to dry out. A loss of moisture within these
materials could result in an increase in the material’s expansive potential. Subsequent wetting of
these materials could result in undesirable movement.
4.2.6 Utility Trench Backfill
All trench excavations should be made with sufficient working space to permit construction including
backfill placement and compaction.
All underground piping within or near the proposed structures should be designed with flexible
couplings, so minor deviations in alignment do not result in breakage or distress. Utility knockouts
should be oversized to accommodate differential movements. It is imperative that utility trenches be
properly backfilled with relatively clean materials. If utility trenches are backfilled with relatively
clean granular material, they should be capped with at least 18 inches of cohesive fill in non-
pavement areas to reduce the infiltration and conveyance of surface water through the trench
backfill.
Utility trenches are a common source of water infiltration and migration. All utility trenches that
penetrate beneath the buildings should be effectively sealed to restrict water intrusion and flow
through the trenches that could migrate below the buildings. We recommend constructing an
effective clay “trench plug” that extends at least 5 feet out from the face of the building exteriors.
The plug material should consist of clay compacted at a water content at or above the soil’s optimum
water content. The clay fill should be placed to completely surround the utility line and be compacted
in accordance with recommendations in this report.
It is strongly recommended that a representative of Terracon provide full-time observation and
compaction testing of trench backfill within building and pavement areas.
4.2.7 Grading and Drainage
All grades must be adjusted to provide effective drainage away from the proposed buildings during
construction and maintained throughout the life of the proposed project. Infiltration of water into
foundation excavations must be prevented during construction. Landscape irrigation adjacent to
foundations should be minimized or eliminated. Water permitted to pond near or adjacent to the
perimeter of the structures (either during or post-construction) can result in significantly higher
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soil movements than those discussed in this report. As a result, any estimations of potential
movement described in this report cannot be relied upon if positive drainage is not obtained and
maintained, and water is allowed to infiltrate the fill and/or subgrade.
Exposed ground (if any) should be sloped at a minimum of 10 percent grade for at least 10 feet
beyond the perimeter of the proposed buildings, where possible. The use of swales, chases
and/or area drains may be required to facilitate drainage in unpaved areas around the perimeter
of the buildings. Backfill against foundations and exterior walls should be properly compacted and
free of all construction debris to reduce the possibility of moisture infiltration. After construction
of the proposed buildings and prior to project completion, we recommend verification of final
grading be performed to document positive drainage, as described above, has been achieved.
Flatwork and pavements will be subject to post-construction movement. Maximum grades
practical should be used for paving and flatwork to prevent areas where water can pond. In
addition, allowances in final grades should take into consideration post-construction movement
of flatwork, particularly if such movement would be critical. Where paving or flatwork abuts the
structures, care should be taken that joints are properly sealed and maintained to prevent the
infiltration of surface water.
Planters located adjacent to structures should preferably be self-contained. Sprinkler mains and
spray heads should be located a minimum of 5 feet away from the building line(s). Low-volume,
drip style landscaped irrigation should not be used near the building. Roof drains should
discharge on to pavements or be extended away from the structures a minimum of 10 feet through
the use of splash blocks or downspout extensions. A preferred alternative is to have the roof
drains discharge by solid pipe to storm sewers or to a detention pond or other appropriate outfall.
4.2.8 Exterior Slab Design and Construction
Exterior slabs on-grade, exterior architectural features, and utilities founded on, or in backfill or
the site soils will likely experience some movement due to the volume change of the material.
Potential movement could be reduced by:
n Minimizing moisture increases in the backfill;
n Controlling moisture-density during placement of the backfill;
n Using designs which allow vertical movement between the exterior features and
adjoining structural elements; and
n Placing control joints on relatively close centers.
4.3 Foundations
The proposed building can be supported by a post-tensioned slab foundation system. Design
recommendations for foundations for the proposed structure and related structural elements are
presented in the following paragraphs.
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4.3.1 Post-Tensioned Slab Design Recommendations
Based on the soil conditions encountered, use of post-tensioned slabs is feasible for support of
structures provided some potential for movement can be tolerated and:
n The post-tensioned slab foundations are properly designed and constructed.
n Approved materials underlying the foundation are properly placed and compacted.
n Proper surface drainage is maintained throughout the life of the structures.
n Managed landscaping measures are used.
In our opinion, total foundation movements on the order of about 1 inch should be expected,
provided our recommendations are followed. Proper drainage should be provided on the design
and during construction to reduce potential movement.
Provided foundations are properly designed, foundation movements could result in periodic, and
possibly seasonal, cosmetic distress to drywall, window frames, door frames and other features.
We would anticipate that the frequency of distress and amount of movement would generally
diminish with time provided proper drainage is established and/or maintained. If the amount of
movement and potential distress discussed cannot be tolerated, the use of drilled pier foundations
and structural floor systems should be considered.
It should be noted that the presences of 1 to 2-foot steps within long spans of post-tensioned
slabs could create a situation where the slabs at different elevations perform independently of
one another unless the steps are properly reinforced and designed to tie the slabs together to act
as one rigid structure. We strongly recommend that joints be designed within the full height of
the structure of the building over each step in order to help the structure be capable of
withstanding movements on the order of 1 inch or more.
Based on the subsurface conditions and the recommended modification of the on-site materials,
post-tensioned slabs should be designed using criteria outlined by the Post-Tensioning Institute4
based on the following:
Post-tensioned Slab Design Parameter PTI, Third Edition
Edge moisture variation distance, em(feet)
Center Lift Condition 9
Edge Lift Condition 5
Differential soil movement, ym (inches)
Center Lift Condition 1-1/2
Edge Lift Condition 1-1/4
Description Value
Foundation subgrade soils Native clay soils
1 (2004, Third Edition), Design (and Construction) of Post-Tensioned Slabs-on-Ground, Post-
Tensioning Institute.
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Maximum allowable bearing pressure (psf) 1,500
Slab-subgrade friction coefficient, m
on polyethylene sheeting 0.75
on cohesionless soils 1.00
on cohesive soils 2.00
Post-tensioned slabs, thickened or turndown edges and/or interior beams should be designed
and constructed in accordance with the requirements of the PTI and the American Concrete
Institute (ACI).
It should be noted that ym is the estimated vertical movement at the edges of a uniformly loaded
slab. These are theoretical values that are used in the design of post-tensioned slabs-on-grade
and do not represent the movements that would be expected from the actual loading conditions.
As previously discussed, the use of post-tensioned slabs assumes that some potential movement
and cosmetic distress is considered acceptable.
If portions of the buildings floor slab will be unheated, such as patios and entryways, consideration
should be given to structurally separating these areas of the slab from the remaining interior
portion of the slab. Exterior slab areas may be cantilevered portions of the slab which are subject
to uplift from frost heave and swelling of the expansive soils, sometimes beyond those used for
design, due to over watering of adjacent landscaped areas. Such movement in the exterior slabs
can result in change in slab grade to the point where negative grade results and water ponds
adjacent to the interior areas of the slab. Repairs of such conditions are difficult and costly,
particularly if the floor slabs are post-tensioned slabs.
Exterior slabs in unheated areas are subject to frost heave beneath the slab. Therefore, in design
of the exterior slabs, potential movement from frost heave should be considered in the design. As
the slabs are subject to frost development beneath the slab, the perimeter beams around exterior
post-tensioned slabs need not be 36 inches in depth as frost protection is not possible.
Masonry walls should be detailed and reinforced as necessary to reduce the potential for distress
caused by differential foundation movement. The use of joints at openings or other discontinuities
in masonry walls is recommended.
4.3.2 Post-Tensioned Slab Construction Considerations
The above outlined movement estimates should also be considered as the potential amount of
tilting of the structure, which could be caused by non-uniform, significant wetting of the subsurface
materials below the post-tensioned slab. Failure to maintain soil water content below the slab
and to maintain proper drainage around the structure will nullify the movement estimates provided
above.
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4.3.3 Post-Tensioned Slabs – Construction Considerations
Post-tensioned slabs, thickened or turndown edges and/or interior beams should be designed
and constructed in accordance with the requirements of the PTI and the American Concrete
Institute (ACI).
As previously discussed, foundations should be protected from frost heave using insulation. If
traditional post-tensioned slab foundations are selected, exterior slab edges should be placed a
minimum of 30 inches below finished grade for frost protection. Finished grade is the lowest
adjacent grade for perimeter beams. Extending exterior slab edges to depths of at least 30 inches
will likely encroach upon soft to very loose and nearly saturated to wet soils requiring stabilization
of subgrade prior to construction.
If portions of the building floor slab will be unheated, such as patios and entryways, consideration
should be given to structurally separating these areas of the slab from the remaining interior
portion of the slab. Exterior slab areas may be cantilevered portions of the slab which are subject
to uplift from frost heave and swelling of the expansive soils, sometimes beyond those used for
design, due to over watering of adjacent to landscaped areas. Such movement in the exterior
slabs can result in change in slab grade to the point where negative grade results and water ponds
adjacent to the interior areas of the slab. Repairs of such conditions are difficult and costly,
particularly if the floor slabs are post-tensioned slabs.
Exterior slabs in unheated areas are subject to frost heave beneath the slab. Therefore, in design
of the exterior slabs, potential movement from frost heave should be considered in the design.
It should be noted that the presences of 1 to 2-foot steps within long spans of post-tensioned
slabs could create a situation where the slabs at different elevations perform independently of
one another unless the steps are properly reinforced and designed to tie the slabs together to act
as one rigid structure. We strongly recommend that joints be designed within the full height of
the structure of the building over each step in order to help the structure be capable of
withstanding movements on the order of 1 inch.
The estimated movement should also be considered as the potential amount of tilting of the
structure, which could be caused by non-uniform, significant wetting of the subsurface materials
below the post-tensioned slab, resulting in potential movement. Failure to maintain soil water
content below the slab and to maintain proper drainage around the structure will nullify the
movement estimates provided above.
4.3.4 Spread Footings - Design Recommendations
Some structural elements or site features may be constructed on shallow spread footing
foundations. However, there are certain precautions we recommend to reduce risk for significant
foundation movements and to enhance performance
Blow counts recorded during sampling of the upper soils within the borings suggest shallow
footing foundations may settle without any ground modification. We recommend over-excavating
Geotechnical Engineering Report
Oakridge Crossing ■ Fort Collins, Colorado
March 10, 2016 ■ Terracon Project No. 20165021
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the soils below these shallow footing foundations to a depth of 2 feet and replacing with
recompacted engineered fill. On-site soils or imported granular fill may be reused as over-
excavation backfill (engineered fill). Subgrade soils at the base of the over-excavation should be
properly scarified, moisture conditioned, and compacted as described in the 4.2 Earthwork
section of our initial report. Design recommendations for spread footing foundations and related
structural elements are presented in the following paragraphs.
Description Values
Bearing material Properly prepared on-site soil
Maximum allowable bearing pressure 1 1,500 psf
Lateral earth pressure coefficients 2
Active, Ka = 0.41
Passive, Kp = 2.46
At-rest, Ko = 0.58
Sliding coefficient 2 µ = 0.37
Moist soil unit weight ɣ = 125 pcf
Minimum embedment depth below finished
grade 3 30 inches
Estimated total movement 4 About 1 inch
Estimated differential movement 4 About ½ to ¾ of total movement
1. The recommended maximum allowable bearing pressure assumes any unsuitable fill or soft soils, if
encountered, will be over-excavated and replaced with properly compacted engineered fill. The
design bearing pressure applies to a dead load plus design live load condition. The design bearing
pressure may be increased by one-third when considering total loads that include wind or seismic
conditions.
2. The lateral earth pressure coefficients and sliding coefficients are ultimate values and do not include
a factor of safety. The foundation designer should include the appropriate factors of safety.
3. For frost protection and to reduce the effects of seasonal moisture variations in the subgrade soils.
The minimum embedment depth is for perimeter footings beneath unheated areas and is relative to
lowest adjacent finished grade, typically exterior grade.
4. The estimated movements presented above are based on the assumption that the maximum footing
size is 4 feet for column footings and 1.5 feet for continuous footings.
Footings should be proportioned to reduce differential foundation movement. As discussed, total
movement resulting from the assumed structural loads is estimated to be on the order of about 1
inch. 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 and throughout the life of the structure. Failure to maintain the proper drainage as
recommended in the 4.2.7 Grading and Drainage section of this report will nullify the movement
estimates provided above.
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Oakridge Crossing ■ Fort Collins, Colorado
March 10, 2016 ■ Terracon Project No. 20165021
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4.3.5 Spread Footings - Construction Considerations
Spread footing construction should only be considered if the estimated foundation movement can
be tolerated. Subgrade soils beneath footings should be moisture conditioned and compacted as
described in the 4.2 Earthwork section of this report. The moisture content and compaction of
subgrade soils should be maintained until foundation construction.
Footings and foundation walls should be reinforced as necessary to reduce the potential for distress
caused by differential foundation movement.
Unstable surfaces will need to be stabilized prior to backfilling excavations and/or constructing
the building foundation, floor slab and/or project pavements. The use of angular rock, recycled
concrete and/or gravel pushed or “crowded” into the yielding subgrade is considered suitable
means of stabilizing the subgrade. The use of geogrid materials in conjunction with gravel could
also be considered and could be more cost effective.
Unstable subgrade conditions should be observed by Terracon to assess the subgrade and
provide suitable alternatives for stabilization. Stabilized areas should be proof-rolled prior to
continuing construction to assess the stability of the subgrade.
Foundation excavations should be observed by Terracon. If the soil conditions encountered differ
significantly from those presented in this report, supplemental recommendations will be required.
4.3.6 Overexcavation Beneath Footings
If unsuitable bearing soils are encountered in footing excavations, the excavations could be
extended deeper to suitable soils and the footings could bear directly on these soils at the lower
level or on lean concrete backfill placed in the excavations. As an alternative, the footings could
also bear on properly compacted backfill extending down to the suitable soils. Over-excavation
for compacted backfill placement below footings should extend laterally beyond all edges of the
footings at least 8 inches per foot of over-excavation depth below footing base elevation. The
over-excavation should then be backfilled up to the footing base elevation with approved granular
materials placed in lifts of 9 inches or less in loose thickness (6 inches or less if using hand-guided
compaction equipment) and compacted to at least 98 percent of the maximum dry unit weight as
determined by ASTM D698. The over-excavation and backfill procedure is described in the
following figure.
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4.4 Seismic Considerations
Code Used Site Classification
2012 International Building Code (IBC) 1 D 2
1. In general accordance with the 2012 International Building Code, Table 1613.5.2.
2. The 2012 International Building Code (IBC) requires a site soil profile determination
extending a depth of 100 feet for seismic site classification. The current scope requested
does not include the required 100 foot soil profile determination. The borings completed for
this project extended to a maximum depth of about 25½ feet and this seismic site class
definition considers that similar soil and bedrock conditions exist below the maximum depth
of the subsurface exploration. Additional exploration to deeper depths could be performed to
confirm the conditions below the current depth of exploration. Alternatively, a geophysical
exploration could be utilized in order to attempt to justify a more favorable seismic site class.
However, we believe a higher seismic site class for this site is unlikely.
4.5 Lateral Earth Pressures
Reinforced concrete walls with unbalanced backfill levels on opposite sides should be designed
for earth pressures at least equal to those indicated in the following table. Earth pressures will be
influenced by structural design of the walls, conditions of wall restraint, methods of construction
and/or compaction and the strength of the materials being restrained. Two wall restraint
conditions are shown. Active earth pressure is commonly used for design of free-standing
cantilever retaining walls and assumes wall movement. The "at-rest" condition assumes no wall
movement. The recommended design lateral earth pressures do not include a factor of safety
and do not provide for possible hydrostatic pressure on the walls.
Geotechnical Engineering Report
Oakridge Crossing ■ Fort Collins, Colorado
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EARTH PRESSURE COEFFICIENTS
Earth Pressure
Conditions
Coefficient for Backfill
Type
Equivalent Fluid
Density (pcf)
Surcharge
Pressure,
p1 (psf)
Earth
Pressure,
p2 (psf)
Active (Ka)
Imported Fill - 0.27
Lean Clay - 0.41
34
51
(0.27)S
(0.41)S
(34)H
(51)H
At-Rest (Ko)
Imported Fill - 0.43
Lean Clay - 0.58
54
72
(0.43)S
(0.58)S
(54)H
(72)H
Passive (Kp)
Imported Fill - 3.69
Lean Clay - 2.46
460
300
---
---
---
---
Applicable conditions to the above include:
n For active earth pressure, wall must rotate about base, with top lateral movements of about
0.002 H to 0.004 H, where H is wall height;
n For passive earth pressure to develop, wall must move horizontally to mobilize resistance;
n Uniform surcharge, where S is surcharge pressure;
n In-situ soil backfill weight a maximum of 125 pcf;
n Horizontal backfill, compacted between 95 and 98 percent of maximum dry unit weight as
determined by ASTM D698;
n Loading from heavy compaction equipment not included;
n No hydrostatic pressures acting on wall;
n No dynamic loading;
n No safety factor included in soil parameters; and
n Ignore passive pressure in frost zone.
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To control hydrostatic pressure behind the wall we recommend that a drain be installed at the
foundation wall with a collection pipe leading to a reliable discharge. If this is not possible, then
combined hydrostatic and lateral earth pressures should be calculated for lean clay backfill using
an equivalent fluid weighing 90 and 100 pcf for active and at-rest conditions, respectively. For
granular backfill, an equivalent fluid weighing 85 and 90 pcf should be used for active and at-rest,
respectively. These pressures do not include the influence of surcharge, equipment or floor
loading, which should be added. Heavy equipment should not operate within a distance closer
than the exposed height of retaining walls to prevent lateral pressures more than those provided.
4.6 Pavements
4.6.1 Pavements – Subgrade Preparation
On most project sites, the site grading is accomplished relatively early in the construction phase.
Fills are typically placed and compacted in a uniform manner. However as construction proceeds,
the subgrade may be disturbed due to utility excavations, construction traffic, desiccation, or
rainfall/snow melt. As a result, the pavement subgrade may not be suitable for pavement
construction and corrective action will be required. Additionally, existing undocumented fill was
encountered on this site that may not provide adequate support for new pavements. The
subgrade should be carefully evaluated at the time of pavement construction for signs of
disturbance or instability. We recommend the pavement subgrade be thoroughly proofrolled with
a loaded tandem-axle dump truck prior to final grading and paving. All pavement areas should
be moisture conditioned and properly compacted to the recommendations in this report
immediately prior to paving.
4.6.2 Pavements – Design Recommendations
Design of new privately-maintained pavements for the project has been based on the procedures
described by the National Asphalt Pavement Associations (NAPA) and the American Concrete
Institute (ACI).
We assumed the following design parameters for NAPA flexible pavement thickness design:
n Automobile Parking Areas
· Class I - Parking stalls and parking lots for cars and pick-up trucks, with
Equivalent Single Axle Load (ESAL) up to 7,000 over 20 years
n Main Traffic Corridors
· Class II – Parking lots with a maximum of 10 trucks per day with Equivalent
Single Axle Load (ESAL) up to 27,000 over 20 years (Including trash trucks)
n Heavy Traffic Areas
· Class III – Collector streets with a maximum of 10 trucks per day with
Equivalent Single Axle Load (ESAL) up to 110,000 over 20 years
n Subgrade Soil Characteristics
· USCS Classification – CL, classified by NAPA as poor
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We assumed the following design parameters for ACI rigid pavement thickness design based
upon the average daily truck traffic (ADTT):
n Automobile Parking Areas (Light Duty)
· ACI Category A: Automobile parking with an ADTT of 1 over 20 years
n Main Traffic Corridors (Medium Duty)
· ACI Category B: Entrance and service lanes with an ADTT of up to 300 over
20 years (Including trash trucks)
n Truck Entrance and Exterior Lanes (Heavy Duty)
· ACI Category C: Entrance and exterior lanes with an ADTT of up to 700 over
20 years
n Subgrade Soil Characteristics
· USCS Classification – CL
n Concrete modulus of rupture value of 600 psi
We should be contacted to confirm and/or modify the recommendations contained herein if actual
traffic volumes differ from the assumed values shown above.
Recommended alternatives for flexible and rigid pavements are summarized for each traffic area
as follows:
Traffic Area
Alternative
Recommended Pavement Thickness (Inches)
Asphaltic
Concrete
Surface
Aggregate
Base
Course
Portland
Cement
Concrete
Total
Automobile Parking
(light duty)
A 3 6 -- 9
B -- -- 5½ 5½
Main Traffic Corridors
(medium duty)
A 4½ 6 -- 10½
B -- -- 6 6
Truck Entrance and Exterior Lanes
(heavy duty)
A 6 6 -- 12
B -- -- 7 7
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 (CDOT) Class 5 or 6 specifications is recommended for aggregate
base course. Aggregate base course should be placed in lifts not exceeding 6 inches and
compacted to a minimum of 95 percent of the maximum dry unit weight as determined by ASTM
D698.
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March 10, 2016 ■ Terracon Project No. 20165021
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Asphaltic concrete should be composed of a mixture of aggregate, filler and additives (if required)
and approved bituminous material. The asphalt concrete should conform to approved mix
designs stating the Superpave properties, optimum asphalt content, job mix formula and
recommended mixing and placing temperatures. Aggregate used in asphalt concrete should
meet particular gradations. Material meeting CDOT Grading S or SX specifications or equivalent
is recommended for asphalt concrete. Mix designs should be submitted prior to construction to
verify their adequacy. Asphalt material should be placed in maximum 3-inch lifts and compacted
within a range of 92 to 96 percent of the theoretical maximum (Rice) density (ASTM D2041).
Where rigid pavements are used, the concrete should be produced from an approved mix design
with the following minimum properties:
Properties Value
Compressive strength 4,000 psi
Cement type Type I or II portland cement
Entrained air content (%) 5 to 8
Concrete aggregate ASTM C33 and CDOT Section 703
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. Longitudinal and transverse joints should be provided
as needed in concrete pavements for expansion/contraction and isolation per ACI 325. The
location and extent of joints should be based upon the final pavement geometry. Joints should
be sealed to prevent entry of foreign material and doweled where necessary for load transfer.
For areas subject to concentrated and repetitive loading conditions such as dumpster pads, truck
delivery docks and ingress/egress aprons, we recommend using a portland cement concrete
pavement with a thickness of at least 6 inches underlain by at least 4 inches of granular base.
Prior to placement of the granular base, the areas should be thoroughly proofrolled. For dumpster
pads, the concrete pavement area should be large enough to support the container and tipping
axle of the refuse truck.
Pavement performance is affected by its surroundings. In addition to providing preventive
maintenance, the civil engineer should consider the following recommendations in the design and
layout of pavements:
n Site grades should slope a minimum of 2 percent away from the pavements;
n The subgrade and the pavement surface have a minimum 2 percent slope to promote
proper surface drainage;
n Consider appropriate edge drainage and pavement under drain systems;
n Install pavement drainage surrounding areas anticipated for frequent wetting;
n Install joint sealant and seal cracks immediately;
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Oakridge Crossing ■ Fort Collins, Colorado
March 10, 2016 ■ Terracon Project No. 20165021
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n Seal all landscaped areas in, or adjacent to pavements to reduce moisture migration to
subgrade soils; and
n Placing compacted, low permeability backfill against the exterior side of curb and gutter.
4.6.3 Pavements – Construction Considerations
Openings in pavement, such as landscape islands, are sources for water infiltration into
surrounding pavements. Water collects in the islands and migrates into the surrounding subgrade
soils thereby degrading support of the pavement. This is especially applicable for islands with
raised concrete curbs, irrigated foliage, and low permeability near-surface soils. The civil design
for the pavements with these conditions should include features to restrict or to collect and
discharge excess water from the islands. Examples of features are edge drains connected to the
storm water collection system or other suitable outlet and impermeable barriers preventing lateral
migration of water such as a cutoff wall installed to a depth below the pavement structure.
4.6.4 Pavements – Maintenance
Preventative maintenance should be planned and provided for an ongoing pavement
management program in order to enhance future pavement performance. Preventive
maintenance consists of both localized maintenance (e.g. crack and joint 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.
5.0 GENERAL COMMENTS
Terracon’s Scope of Services has been provided under the belief that this site will be used as
apartments. As such, Terracon would like to inform the Client that if this apartment project is
converted at any time to another purpose such as condominiums, the Client understands the
services Terracon is providing is not applicable for a condominium project and that a separate
consultant will need to be retained for such services. Terracon will have no liability for any such
unintended use of our services and Client agrees to defend, indemnify, and hold harmless
Terracon for any such unintended usage.
Terracon should be retained to review the final design plans and specifications so comments can
be made regarding interpretation and implementation of our geotechnical recommendations in
the design and specifications. Terracon also should be retained to provide observation and testing
services during grading, excavation, foundation construction and other earth-related construction
phases of the project.
The analysis and recommendations presented in this report are based upon the data obtained
from the borings performed at the indicated locations and from other information discussed in this
report. This report does not reflect variations that may occur between borings, across the site, or
due to the modifying effects of construction or weather. The nature and extent of such variations
may not become evident until during or after construction. If variations appear, we should be
Geotechnical Engineering Report
Oakridge Crossing ■ Fort Collins, Colorado
March 10, 2016 ■ Terracon Project No. 20165021
Responsive ■ Resourceful ■ Reliable 21
immediately notified so that further evaluation and supplemental recommendations can be
provided.
The scope of services for this project does not include either specifically or by implication any
environmental or biological (e.g., mold, fungi, and bacteria) assessment of the site or identification
or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about
the potential for such contamination or pollution, other studies should be undertaken.
This report has been prepared for the exclusive use of our client for specific application to the
project discussed and has been prepared in accordance with generally accepted geotechnical
engineering practices. No warranties, either express or implied, are intended or made. Site
safety, excavation support, and dewatering requirements are the responsibility of others. In the
event that changes in the nature, design, or location of the project as described in this report are
planned, the conclusions and recommendations contained in this report shall not be considered
valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this
report in writing.
APPENDIX A
FIELD EXPLORATION
SITE LOCATION MAP
Oakridge Crossing
Southeast of Oakridge Drive and McMurry Avenue
Fort Collins, CO
TOPOGRAPHIC MAP IMAGE COURTESY OF THE U.S. GEOLOGICAL SURVEY
QUADRANGLES INCLUDE: FORT COLLINS, CO (1984) and LOVELAND, CO (1984).
1901 Sharp Point Dr Ste C
Fort Collins, CO 80525-4429
20165021
Project Manager:
Drawn by:
Checked by:
Approved by:
KFS
EDB
EDB
1”=2,000’
3/4/16
Project No.
Scale:
File Name:
Date: A-1
EDB Exhibit
SITE
0’ 20’ 40’
APPROXIMATE SCALE
Scale:
EDB
KFS
EDB
EDB
Project Manager:
Drawn by:
Checked by:
Approved by:
EXPLORATION PLAN
Oakridge Crossing
Southeast of Oakridge Drive and McMurry Avenue
Fort Collins, Colorado A-2
20165021 Exhibit
3/10/16
1=40’
Project No.
File Name:
DIAGRAM IS FOR GENERAL LOCATION ONLY, AND Date:
IS NOT INTENDED FOR CONSTRUCTION PURPOSES
1 APPROXIMATE BORING LOCATION
LEGEND
B-1
B-4
B-5
1901 Sharp Point Drive, Suite C Fort Collins, Colorado 80525
PH. (970) 484-0359 FAX. (970) 484-0454
P-1
P-2
P-3
B-2
B-3
TBM
TBM APPROXIMATE LOCATION OF
TEMPORARY BENCHMARK
(CONCRETE CURB-ASSUMED
ELEVATION 100.0)
Geotechnical Engineering Report
Oakridge Crossing ■ Fort Collins, Colorado
March 10, 2016 ■ Terracon Project No. 20165021
Responsive ■ Resourceful ■ Reliable Exhibit A-3
Field Exploration Description
The locations of borings were based upon the proposed development shown on the provided site
plan. The borings were located in the field by measuring from property lines and existing site
features. The ground surface elevation was surveyed at each boring location referencing the
temporary benchmark shown on Exhibit A-2 using an engineer’s level.
The borings were drilled with a CME-75 truck-mounted rotary drill rig with solid-stem augers.
During the drilling operations, lithologic logs of the borings were recorded by the field engineer.
Disturbed samples were obtained at selected intervals utilizing a 2-inch outside diameter split-
spoon sampler and a 3-inch outside diameter ring-barrel sampler. Penetration resistance values
were recorded in a manner similar to the standard penetration test (SPT). This test consists of
driving the sampler into the ground with a 140-pound hammer free-falling through a distance of
30 inches. The number of blows required to advance the ring-barrel sampler 12 inches (18 inches
for standard split-spoon samplers, final 12 inches are recorded) or the interval indicated, is
recorded as a standard penetration resistance value (N-value). The blow count values are
indicated on the boring logs at the respective sample depths. Ring-barrel sample blow counts are
not considered N-values.
A CME automatic SPT hammer was used to advance the samplers in the borings performed on this
site. A greater efficiency is typically achieved with the automatic hammer compared to the
conventional safety hammer operated with a cathead and rope. Published correlations between the
SPT values and soil properties are based on the lower efficiency cathead and rope method. This
higher efficiency affects the standard penetration resistance blow count value by increasing the
penetration per hammer blow over what would be obtained using the cathead and rope method. The
effect of the automatic hammer's efficiency has been considered in the interpretation and analysis of
the subsurface information for this report.
The standard penetration test provides a reasonable indication of the in-place density of sandy
type materials, but only provides an indication of the relative stiffness of cohesive materials since
the blow count in these soils may be affected by the moisture content of the soil. In addition,
considerable care should be exercised in interpreting the N-values in gravelly soils, particularly
where the size of the gravel particle exceeds the inside diameter of the sampler.
Groundwater measurements were obtained in the borings at the time of site exploration and
several days after drilling. After subsequent groundwater measurements were obtained, the
borings were backfilled with auger cuttings. Some settlement of the backfill may occur and should
be repaired as soon as possible.
13
14
14
20
16
91
90
76
4-4-5
N=9
7-11
5-13-27
N=40
50/2"
50/6"
50/5"
9.0
10.0
24.4
SANDY LEAN CLAY, fine to coarse grained, brown to
reddish-brown, stiff
WEATHERED BEDROCK, CLAYEY SAND, light
brown, dense
INTERBEDDED SANDSTONE AND CLAYSTONE,
light brown to olive, very hard
Boring Terminated at 24.4 Feet
Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic
GRAPHIC LOG
THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20165021.GPJ TERRACON2015.GDT 3/10/16
Oakridge Drive and McMurry Avenue
Fort Collins, CO
SITE:
Page 1 of 1
Advancement Method:
4-inch continuous flight auger
Abandonment Method:
Borings backfilled with soil cuttings upon completion.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
Notes:
Project No.: 20165021
Drill Rig: CME-75
Boring Started: 2/25/2016
BORING LOG NO. 1
CLIENT: McDermott Properties
Centennial, Colorado
Driller: ROB
Boring Completed: 2/25/2016
Exhibit: A-4
See Exhibit A-3 for description of field procedures.
See Appendix B for description of laboratory
procedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.
PROJECT: Oakridge Crossing
UNCONFINED
COMPRESSIVE
STRENGTH (psf)
PERCENT FINES
WATER
31
11
16
18
26
19
27-13-14
NP
90
86
84
73.5
9-10
10-17
3-5-4
N=9
4-4-7
N=11
50/6"
50/3"
9.0
13.0
15.0
25.3
SANDY LEAN CLAY, fine to coarse grained, brown to
reddish-brown, stiff
CLAYEY SAND (SC), light brown, loose
INTERBEDDED SANDSTONE AND CLAYSTONE,
light brown to olive, medium dense, highly weathered
INTERBEDDED SANDSTONE AND CLAYSTONE,
light brown to olive, very hard
very hard lense from 24 to 24.7
Boring Terminated at 25.3 Feet
Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic
GRAPHIC LOG
THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20165021.GPJ TERRACON2015.GDT 3/10/16
Oakridge Drive and McMurry Avenue
Fort Collins, CO
SITE:
Page 1 of 1
Advancement Method:
4-inch continuous flight auger
Abandonment Method:
Borings backfilled with soil cuttings upon completion.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
Notes:
Project No.: 20165021
Drill Rig: CME-75
Boring Started: 2/25/2016
BORING LOG NO. 2
CLIENT: McDermott Properties
Centennial, Colorado
Driller: ROB
Boring Completed: 2/25/2016
Exhibit: A-5
See Exhibit A-3 for description of field procedures.
See Appendix B for description of laboratory
procedures and additional data (if any).
See Appendix C for explanation of symbols and
743 67
96
20
23
21
22
19
17
86 27-18-9
51-23-28
92.5
85.5
82.5
75
4-6-5
N=11
5-7
2-3-3
N=6
5-8-8
N=16
19-21-36
N=57
50/6"
7.0
14.0
17.0
24.5
SANDY LEAN CLAY WITH GRAVEL (CL), light brown
to reddish-brown, stiff
SANDY LEAN CLAY, light brown, medium stiff, trace
of crystalline precipitate, moist
WEATHERED BEDROCK, CLAYEY SAND, fine to
coarse grained, brown, medium dense, trace of iron
oxides
INTERBEDDED SANDSTONE AND CLAYSTONE
(CH), brown to olive, hard
Boring Terminated at 24.5 Feet
Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic
GRAPHIC LOG
THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20165021.GPJ TERRACON2015.GDT 3/10/16
Oakridge Drive and McMurry Avenue
Fort Collins, CO
SITE:
Page 1 of 1
Advancement Method:
4-inch continuous flight auger
Abandonment Method:
Borings backfilled with soil cuttings upon completion.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
Notes:
Project No.: 20165021
Drill Rig: CME-75
Boring Started: 2/25/2016
BORING LOG NO. 3
CLIENT: McDermott Properties
Centennial, Colorado
Driller: ROB
Boring Completed: 2/25/2016
19 44
23
5
31-13-18
89.5
88
85
82
75.5
11-17
5-8
1-1-2
N=3
3-3-4
N=7
8-17-19
N=36
50/3"
10.5
12.0
15.0
18.0
24.3
SANDY LEAN CLAY WITH GRAVEL, brown to
reddish-brown, soft to very stiff
WELL GRADED SAND WITH GRAVEL, brown, loose
SANDY LEAN CLAY WITH GRAVEL, brown
POORLY GRADED SAND, brown, loose
SEDIMENTARY BEDROCK - SANDSTONE, fine to
coarse grained, brown to gray, firm to very hard
Boring Terminated at 24.3 Feet
Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic
GRAPHIC LOG
THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20165021.GPJ TERRACON2015.GDT 3/10/16
Oakridge Drive and McMurry Avenue
Fort Collins, CO
SITE:
Page 1 of 1
Advancement Method:
4-inch continuous flight auger
Abandonment Method:
Borings backfilled with soil cuttings upon completion.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
Notes:
Project No.: 20165021
Drill Rig: CME-75
Boring Started: 2/25/2016
BORING LOG NO. 4
CLIENT: McDermott Properties
Centennial, Colorado
Driller: ROB
Boring Completed: 2/25/2016
Exhibit: A-7
See Exhibit A-3 for description of field procedures.
See Appendix B for description of laboratory
procedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.
PROJECT: Oakridge Crossing
3241 59
70
12
12
14
22
23
12
10
97 39-17-22
30-15-15
NP
82
77
76
9-14-15
N=29
5-18
2-3-2
N=5
3-4-2
N=6
10-12-14
N=26
17
50/4"
19.0
24.0
24.8
SANDY LEAN CLAY (CL), fine to coarse grained, dark
brown to light brown, medium stiff to very stiff, trace
sulfate
WELL GRADED SAND WITH CLAY AND GRAVEL,
brown, medium dense
SEDIMENTARY BEDROCK - SANDSTONE, brown,
hard, trace iron oxide
Boring Terminated at 24.8 Feet
Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic
GRAPHIC LOG
THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20165021.GPJ TERRACON2015.GDT 3/10/16
Oakridge Drive and McMurry Avenue
Fort Collins, CO
SITE:
Page 1 of 1
Advancement Method:
4-inch continuous flight auger
Abandonment Method:
Borings backfilled with soil cuttings upon completion.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
Notes:
Project No.: 20165021
Drill Rig: CME-75
Boring Started: 2/25/2016
BORING LOG NO. 5
CLIENT: McDermott Properties
Centennial, Colorado
Driller: ROB
Boring Completed: 2/25/2016
Exhibit: A-8
4
16
20
19
13
103
25-13-12
95.5
90
-2.38/500
3-3-3
N=6
4-7
2-3-3
N=6
3-3-3
N=6
5.0
10.5
SANDY LEAN CLAY, reddish-brown to brown, medium
stiff to stiff
WELL GRADED SAND WITH CLAY AND GRAVEL
(SW), reddish-brown to brown, loose
Boring Terminated at 10.5 Feet
Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic
GRAPHIC LOG
THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20165021.GPJ TERRACON2015.GDT 3/10/16
Oakridge Drive and McMurry Avenue
Fort Collins, CO
SITE:
Page 1 of 1
Advancement Method:
4-inch continuous flight auger
Abandonment Method:
Borings backfilled with soil cuttings upon completion.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
Notes:
Project No.: 20165021
Drill Rig: CME-75
Boring Started: 2/25/2016
BORING LOG NO. P1
CLIENT: McDermott Properties
Centennial, Colorado
Driller: ROB
Boring Completed: 2/25/2016
Exhibit: A-9
See Exhibit A-3 for description of field procedures.
See Appendix B for description of laboratory
procedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.
PROJECT: Oakridge Crossing
UNCONFINED
COMPRESSIVE
STRENGTH (psf)
PERCENT FINES
WATER
CONTENT (%)
DRY UNIT
17
14
113
92.5
91.5
89.5
8-8-9 1.4/250
26-23
6-6-4
10-6
7.0
8.0
10.0
SANDY LEAN CLAY, light brown, very stiff
POORLY GRADED SAND, light brown, medium dense
SANDY LEAN CLAY, light brown, stiff
Boring Terminated at 10 Feet
Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic
GRAPHIC LOG
THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20165021.GPJ TERRACON2015.GDT 3/10/16
Oakridge Drive and McMurry Avenue
Fort Collins, CO
SITE:
Page 1 of 1
Advancement Method:
4-inch continuous flight auger
Abandonment Method:
Borings backfilled with soil cuttings upon completion.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
Notes:
Project No.: 20165021
Drill Rig: CME-75
Boring Started: 2/25/2016
BORING LOG NO. P2
CLIENT: McDermott Properties
Centennial, Colorado
Driller: ROB
Boring Completed: 2/25/2016
Exhibit: A-10
See Exhibit A-3 for description of field procedures.
See Appendix B for description of laboratory
procedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.
PROJECT: Oakridge Crossing
UNCONFINED
COMPRESSIVE
STRENGTH (psf)
PERCENT FINES
WATER
CONTENT (%)
DRY UNIT
WEIGHT (pcf)
ATTERBERG
LIMITS
LL-PL-PI
Surface Elev.: 99.49 (Ft.)
ELEVATION (Ft.)
SAMPLE TYPE
68
24
21
21
25
105
36-15-21
90.5
2-4-4
N=8
3-5-7
N=12
8-7
4-4-4
10.5 N=8
SANDY LEAN CLAY (CL), dark brown to
reddish-brown, stiff
Boring Terminated at 10.5 Feet
Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic
GRAPHIC LOG
THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20165021.GPJ TERRACON2015.GDT 3/10/16
Oakridge Drive and McMurry Avenue
Fort Collins, CO
SITE:
Page 1 of 1
Advancement Method:
4-inch continuous flight auger
Abandonment Method:
Borings backfilled with soil cuttings upon completion.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
Notes:
Project No.: 20165021
Drill Rig: CME-75
Boring Started: 2/25/2016
BORING LOG NO. P3
CLIENT: McDermott Properties
Centennial, Colorado
Driller: ROB
Boring Completed: 2/25/2016
Exhibit: A-11
See Exhibit A-3 for description of field procedures.
See Appendix B for description of laboratory
procedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.
PROJECT: Oakridge Crossing
UNCONFINED
COMPRESSIVE
STRENGTH (psf)
PERCENT FINES
WATER
CONTENT (%)
DRY UNIT
WEIGHT (pcf)
ATTERBERG
LIMITS
LL-PL-PI
Surface Elev.: 101.16 (Ft.)
ELEVATION (Ft.)
APPENDIX B
LABORATORY TESTING
Geotechnical Engineering Report
Oakridge Crossing ■ Fort Collins, Colorado
March 10, 2016 ■ Terracon Project No. 20165021
Responsive ■ Resourceful ■ Reliable Exhibit B-1
Laboratory Testing Description
The soil and bedrock samples retrieved during the field exploration were returned to the laboratory
for observation by the project geotechnical engineer. At that time, the field descriptions were
reviewed and an applicable laboratory testing program was formulated to determine engineering
properties of the subsurface materials.
Laboratory tests were conducted on selected soil and bedrock samples. The results of these
tests are presented on the boring logs and in this appendix. The test results were used for the
geotechnical engineering analyses, and the development of foundation and earthwork
recommendations. The laboratory tests were performed in general accordance with applicable
locally accepted standards. Soil samples were classified in general accordance with the Unified
Soil Classification System described in Appendix C. Rock samples were visually classified in
general accordance with the description of rock properties presented in Appendix C. Procedural
standards noted in this report are for reference to methodology in general. In some cases variations
to methods are applied as a result of local practice or professional judgment.
n Water content n Plasticity index
n Grain-size distribution
n Consolidation/swell
n Unconfined compressive strength
n Dry density
n Water-soluble sulfate content
0
10
20
30
40
50
60
0 20 40 60 80 100
CL or OL CH or OH
ML or OL
MH or OH
Boring ID Depth PL PI Description
CLAYEY SAND
SANDY LEAN CLAY
FAT CLAY
CLAYEY SAND
SANDY LEAN CLAY
LEAN CLAY with SAND
SILTY SAND with GRAVEL
WELL-GRADED SAND with GRAVEL
SANDY LEAN CLAY
SC
CL
CH
SC
CL
CL
SM
SW
CL
Fines
P
L
A
S
T
I
C
I
T
Y
I
N
D
E
X
LIQUID LIMIT
"U" Line
"A" Line
27
27
51
31
39
30
NP
25
36
13
18
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
100 10 1 0.1 0.01 0.001
GRAIN SIZE IN MILLIMETERS
PERCENT FINER
3/4 1/2
3/8
SIEVE
(size)
D60
30 40
3 60
U.HYDROMETERS. SIEVE OPENING IN INCHES
% FINES % CLAY USCS
1
2
2
0.0
0.0
0.0
0.0
4.5
0.0
43.1
64.0
89.1
31.0
()
CLAYEY SAND (SC)
POORLY GRADED SAND with SILT
(SP-SM)
0.004 0.125
0.088 0.28 0.186
1.15
26.0
DEPTH
GRAIN SIZE
16 20
100
90
80
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
100 10 1 0.1 0.01 0.001
GRAIN SIZE IN MILLIMETERS
PERCENT FINER
3/4 1/2
3/8
SIEVE
(size)
D60
30 40
3 60
U.HYDROMETERS. SIEVE OPENING IN INCHES
% FINES % CLAY USCS
3
3
4
0.0
0.0
1.7
0.0
31.6
4.2
35.2 34.9
SANDY LEAN CLAY (CL)
FAT CLAY (CH)
()
0.002
0.054
29.9
DEPTH
GRAIN SIZE
16 20
100
90
80
70
60
50
40
30
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
100 10 1 0.1 0.01 0.001
GRAIN SIZE IN MILLIMETERS
PERCENT FINER
3/4 1/2
3/8
SIEVE
(size)
D60
30 40
3 60
U.HYDROMETERS. SIEVE OPENING IN INCHES
% FINES % CLAY USCS
4
5
5
0.0
0.0
2.2
6.7
0.3
46.9
34.2
29.4
CLAYEY SAND (SC)
SANDY LEAN CLAY (CL)
LEAN CLAY with SAND (CLCL)
0.257 0.079
DEPTH
GRAIN SIZE
16 20
100
90
80
70
60
50
40
30
20
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
100 10 1 0.1 0.01 0.001
0.102
GRAIN SIZE IN MILLIMETERS
PERCENT FINER
3/4 1/2
3/8
SIEVE
(size)
D60
30 40
3 60
U.HYDROMETERS. SIEVE OPENING IN INCHES
% FINES % CLAY USCS
5
P1
P2
0.0
0.0
0.0
15.5
24.3
0.0
72.5
71.2
54.9 26.4
SILTY SAND with GRAVEL (SM)
WELL-GRADED SAND with GRAVEL
(SW)
()
0.178 0.527 0.009
1.55 2.276 0.203
0.30 1.19
18.7
DEPTH
GRAIN SIZE
16 20
100
90
80
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
100 10 1 0.1 0.01 0.001
GRAIN SIZE IN MILLIMETERS
PERCENT FINER
3/4 1/2
3/8
SIEVE
(size)
D60
30 40
3 60
U.HYDROMETERS. SIEVE OPENING IN INCHES
% FINES % CLAY USCS
P3 0.0 0.0 32.3
SANDY LEAN CLAY (CL)
DEPTH
GRAIN SIZE
16 20
100
90
80
70
60
50
40
30
20
10
0
REMARKS
COBBLES SILT OR CLAY
GRAVEL SAND
medium
67.7
U.S. SIEVE NUMBERS
4 4 6 100
3 2
fine coarse
SOIL DESCRIPTION
CU
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
100 1,000 10,000
AXIAL STRAIN, %
PRESSURE, psf
SWELL CONSOLIDATION TEST
ASTM D2435
NOTES: Sample exhibited 1.4% swell at an applied load of 250 psf.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
PROJECT: Oakridge Crossing PROJECT NUMBER: 20165021
SITE: Oakridge Drive and McMurry
Avenue
Fort Collins, CO
CLIENT: McDermott Properties
Centennial, Colorado
EXHIBIT: B-9
Specimen Identification Classification , pcf
113 17
WC, %
P2 2 - 3.5 ft SANDY LEAN CLAY
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. 65155045-SWELL/CONSOL 20165021.GPJ TERRACON2012.GDT 3/10/16
-10
-8
-6
-4
-2
0
2
4
100 1,000
AXIAL STRAIN, %
PRESSURE, psf
SWELL CONSOLIDATION TEST
ASTM D4546
NOTES: Sample exhibited 2.4% compression at an applied load of 500 psf.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
PROJECT: Oakridge Crossing PROJECT NUMBER: 20165021
SITE: Oakridge Drive and McMurry
Avenue
Fort Collins, CO
CLIENT: McDermott Properties
Centennial, Colorado
EXHIBIT: B-8
Specimen Identification Classification , pcf
103 20
WC, %
P1 4 - 5 ft SANDY LEAN CLAY
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. 65155045-SWELL/CONSOL 20165021.GPJ TERRACON2012.GDT 3/10/16
0
100
200
300
400
500
600
700
800
0 1.0 2.0 3.0 4.0
2.40
5.35
743
Assumed Specific Gravity:
27 18 9
Unconfined Compressive Strength (psf)
Undrained Shear Strength: (psf)
Calculated Void Ratio:
Height / Diameter Ratio:
SPECIMEN FAILURE MODE SPECIMEN TEST DATA
2.23
2.99
Moisture Content: %
Dry Density: pcf
COMPRESSIVE STRESS - psf
DESCRIPTION: SANDY LEAN CLAY(CL)
23
371
LL PL PI Percent < #200 Sieve
67
AXIAL STRAIN - %
Remarks:
ASTM D2166
UNCONFINED COMPRESSION TEST
Failure Mode: Shear (dashed)
Diameter: in.
Height: in.
Calculated Saturation: %
Failure Strain: %
Strain Rate: in/min
86
SAMPLE TYPE: D&M RING SAMPLE LOCATION: 3 @ 4 - 5 feet
PROJECT NUMBER: 20165021
PROJECT: Oakridge Crossing
SITE: Oakridge Drive and McMurry Avenue
Fort Collins, CO
CLIENT: McDermott Properties
Centennial, Colorado
EXHIBIT: B-10
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. UNCONFINED 20165021.GPJ TERRACON2012.GDT 3/10/16
0
500
1,000
1,500
2,000
2,500
3,000
3,500
0 1 2 3 4 5 6 7 8
2.40
5.96
3241
Assumed Specific Gravity:
39 17 22
Unconfined Compressive Strength (psf)
Undrained Shear Strength: (psf)
Calculated Void Ratio:
Height / Diameter Ratio:
SPECIMEN FAILURE MODE SPECIMEN TEST DATA
2.48
5.04
Moisture Content: %
Dry Density: pcf
COMPRESSIVE STRESS - psf
DESCRIPTION: SANDY LEAN CLAY(CL)
14
1620
LL PL PI Percent < #200 Sieve
59
AXIAL STRAIN - %
Remarks:
ASTM D2166
UNCONFINED COMPRESSION TEST
Failure Mode: Bulge (dashed)
Diameter: in.
Height: in.
Calculated Saturation: %
Failure Strain: %
Strain Rate: in/min
97
SAMPLE TYPE: D&M RING SAMPLE LOCATION: 5 @ 4 - 5 feet
PROJECT NUMBER: 20165021
PROJECT: Oakridge Crossing
SITE: Oakridge Drive and McMurry Avenue
Fort Collins, CO
CLIENT: McDermott Properties
Centennial, Colorado
EXHIBIT: B-11
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. UNCONFINED 20165021.GPJ TERRACON2012.GDT 3/10/16
TASK NO: 160302082
Analytical Results
Terracon, Inc. - Fort Collins
Eric D. Bernhardt
Company:
Report To:
Company:
Bill To:
1901 Sharp Point Drive
Suite C
Fort Collins CO 80525
Accounts Payable
Terracon, Inc. - Lenexa
13910 W. 96th Terrace
Lenexa KS 66215
Date Reported: 3/9/16
Task No.: 160302082
Matrix: Soil - Geotech
Date Received: 3/2/16
Client Project:
Client PO:
Customer Sample ID 20165019 B2 4-6
Test Method
Lab Number: 160302082-01
Result
Sulfate - Water Soluble 0.010 % AASHTO T290-91/ ASTM D4327
Customer Sample ID 20165021 1 @ 2
Test Method
Lab Number: 160302082-02
Result
Sulfate - Water Soluble 0.064 % AASHTO T290-91/ ASTM D4327
Customer19 Sample ID 20165021 4 @
Test Method
Lab Number: 160302082-03
Result
Sulfate - Water Soluble 0.005 % AASHTO T290-91/ ASTM D4327
Customer Sample ID 20165021 3 @ 4
Test Method
Lab Number: 160302082-04
Result
Sulfate - Water Soluble 0.107 % AASHTO T290-91/ ASTM D4327
240 South Main Street / Brighton, CO 80601-0507 / 303-659-2313
Mailing Address: P.O. Box 507 / Brighton, CO 80601-0507 / Fax: 303-659-2315
DATA APPROVED FOR RELEASE BY
Abbreviations/ References:
160302082
AASHTO - American Association of State Highway and Transportation Officials.
ASTM - American Society for Testing and Materials.
ASA - American Society of Agronomy.
DIPRA - Ductile Iron Pipe Research Association Handbook of Ductile Iron Pipe.
APPENDIX C
SUPPORTING DOCUMENTS
Exhibit: C-1
Unconfined Compressive Strength
Qu, (psf)
500 to 1,000
2,000 to 4,000
4,000 to 8,000
1,000 to 2,000
less than 500
> 8,000
Non-plastic
Low
Medium
High
DESCRIPTION OF SYMBOLS AND ABBREVIATIONS
SAMPLING
WATER LEVEL
FIELD TESTS
GENERAL NOTES
Over 12 in. (300 mm)
12 in. to 3 in. (300mm to 75mm)
3 in. to #4 sieve (75mm to 4.75 mm)
#4 to #200 sieve (4.75mm to 0.075mm
Passing #200 sieve (0.075mm)
Particle Size
< 5
5 - 12
> 12
Percent of
Dry Weight
Descriptive Term(s)
of other constituents
RELATIVE PROPORTIONS OF FINES
0
1 - 10
11 - 30
> 30
Plasticity Index
Soil classification is based on the Unified Soil Classification System. Coarse Grained Soils have more than 50% of their dry
weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have
less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and
silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be
added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined
on the basis of their in-place relative density and fine-grained soils on the basis of their consistency.
LOCATION AND ELEVATION NOTES
Percent of
Dry Weight
Major Component
of Sample
Trace
With
Modifier
RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY
Trace
With
Modifier
DESCRIPTIVE SOIL CLASSIFICATION
Boulders
Cobbles
Gravel
Sand
UNIFIED SOIL CLASSIFICATION SYSTEM
Exhibit C-2
Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests A
Soil Classification
Group
Symbol Group Name B
Coarse Grained Soils:
More than 50% retained
on No. 200 sieve
Gravels:
More than 50% of
coarse fraction retained
on No. 4 sieve
Clean Gravels:
Less than 5% fines C
Cu 4 and 1 Cc 3 E GW Well-graded gravel F
Cu 4 and/or 1 Cc 3 E GP Poorly graded gravel F
Gravels with Fines:
More than 12% fines C
Fines classify as ML or MH GM Silty gravel F,G,H
Fines classify as CL or CH GC Clayey gravel F,G,H
Sands:
50% or more of coarse
fraction passes No. 4
sieve
Clean Sands:
Less than 5% fines D
Cu 6 and 1 Cc 3 E SW Well-graded sand I
Cu 6 and/or 1 Cc 3 E SP Poorly graded sand I
Sands with Fines:
More than 12% fines D
Fines classify as ML or MH SM Silty sand G,H,I
Fines classify as CL or CH SC Clayey sand G,H,I
Fine-Grained Soils:
50% or more passes the
No. 200 sieve
Silts and Clays:
Liquid limit less than 50
Inorganic:
PI 7 and plots on or above “A” line J CL Lean clay K,L,M
PI 4 or plots below “A” line J ML Silt K,L,M
Organic:
Liquid limit - oven dried
0.75 OL
Organic clay K,L,M,N
Liquid limit - not dried Organic silt K,L,M,O
Silts and Clays:
Liquid limit 50 or more
Inorganic:
PI plots on or above “A” line CH Fat clay K,L,M
PI plots below “A” line MH Elastic Silt K,L,M
Organic:
Liquid limit - oven dried
0.75 OH
Organic clay K,L,M,P
Liquid limit - not dried Organic silt K,L,M,Q
Highly organic soils: Primarily organic matter, dark in color, and organic odor PT Peat
A Based on the material passing the 3-inch (75-mm) sieve
B If field sample contained cobbles or boulders, or both, add “with cobbles
or boulders, or both” to group name.
DESCRIPTION OF ROCK PROPERTIES
Exhibit C-3
WEATHERING
Fresh Rock fresh, crystals bright, few joints may show slight staining. Rock rings under hammer if crystalline.
Very slight Rock generally fresh, joints stained, some joints may show thin clay coatings, crystals in broken face show
bright. Rock rings under hammer if crystalline.
Slight Rock generally fresh, joints stained, and discoloration extends into rock up to 1 in. Joints may contain clay. In
granitoid rocks some occasional feldspar crystals are dull and discolored. Crystalline rocks ring under hammer.
Moderate Significant portions of rock show discoloration and weathering effects. In granitoid rocks, most feldspars are dull
and discolored; some show clayey. Rock has dull sound under hammer and shows significant loss of strength
as compared with fresh rock.
Moderately severe All rock except quartz discolored or stained. In granitoid rocks, all feldspars dull and discolored and majority
show kaolinization. Rock shows severe loss of strength and can be excavated with geologist’s pick.
Severe All rock except quartz discolored or stained. Rock “fabric” clear and evident, but reduced in strength to strong
soil. In granitoid rocks, all feldspars kaolinized to some extent. Some fragments of strong rock usually left.
Very severe All rock except quartz discolored or stained. Rock “fabric” discernible, but mass effectively reduced to “soil” with
only fragments of strong rock remaining.
Complete Rock reduced to ”soil”. Rock “fabric” not discernible or discernible only in small, scattered locations. Quartz may
be present as dikes or stringers.
HARDNESS (for engineering description of rock – not to be confused with Moh’s scale for minerals)
Very hard Cannot be scratched with knife or sharp pick. Breaking of hand specimens requires several hard blows of
geologist’s pick.
Hard Can be scratched with knife or pick only with difficulty. Hard blow of hammer required to detach hand specimen.
Moderately hard Can be scratched with knife or pick. Gouges or grooves to ¼ in. deep can be excavated by hard blow of point of
a geologist’s pick. Hand specimens can be detached by moderate blow.
Medium Can be grooved or gouged 1/16 in. deep by firm pressure on knife or pick point. Can be excavated in small
chips to pieces about 1-in. maximum size by hard blows of the point of a geologist’s pick.
Soft Can be gouged or grooved readily with knife or pick point. Can be excavated in chips to pieces several inches in
size by moderate blows of a pick point. Small thin pieces can be broken by finger pressure.
Very soft Can be carved with knife. Can be excavated readily with point of pick. Pieces 1-in. or more in thickness can be
broken with finger pressure. Can be scratched readily by fingernail.
Joint, Bedding, and Foliation Spacing in Rock
a
Spacing Joints Bedding/Foliation
Less than 2 in. Very close Very thin
2 in. – 1 ft. Close Thin
1 ft. – 3 ft. Moderately close Medium
3 ft. – 10 ft. Wide Thick
More than 10 ft. Very wide Very thick
a. Spacing refers to the distance normal to the planes, of the described feature, which are parallel to each other or nearly so.
Rock Quality Designator (RQD) a Joint Openness Descriptors
RQD, as a percentage Diagnostic description Openness Descriptor
Exceeding 90 Excellent No Visible Separation Tight
90 – 75 Good Less than 1/32 in. Slightly Open
75 – 50 Fair 1/32 to 1/8 in. Moderately Open
50 – 25 Poor 1/8 to 3/8 in. Open
Less than 25 Very poor 3/8 in. to 0.1 ft. Moderately Wide
a. RQD (given as a percentage) = length of core in pieces Greater than 0.1 ft. Wide
4 in. and longer/length of run.
References: American Society of Civil Engineers. Manuals and Reports on Engineering Practice - No. 56. Subsurface Investigation for
Design and Construction of Foundations of Buildings. New York: American Society of Civil Engineers, 1976. U.S.
Department of the Interior, Bureau of Reclamation, Engineering Geology Field Manual.
Exhibit C-4
LABORATORY TEST
SIGNIFICANCE AND PURPOSE
Test Significance Purpose
California Bearing
Ratio
Used to evaluate the potential strength of subgrade soil,
subbase, and base course material, including recycled
materials for use in road and airfield pavements.
Pavement Thickness
Design
Consolidation
Used to develop an estimate of both the rate and amount of
both differential and total settlement of a structure. Foundation Design
Direct Shear
Used to determine the consolidated drained shear strength
of soil or rock.
Bearing Capacity,
Foundation Design,
and Slope Stability
Dry Density
Used to determine the in-place density of natural, inorganic,
fine-grained soils.
Index Property Soil
Behavior
Expansion
Used to measure the expansive potential of fine-grained soil
and to provide a basis for swell potential classification.
Foundation and Slab
Design
Gradation
Used for the quantitative determination of the distribution of
particle sizes in soil. Soil Classification
Liquid & Plastic Limit,
Plasticity Index
Used as an integral part of engineering classification
systems to characterize the fine-grained fraction of soils, and
to specify the fine-grained fraction of construction materials.
Soil Classification
Permeability
Used to determine the capacity of soil or rock to conduct a
liquid or gas.
Groundwater Flow
Analysis
pH Used to determine the degree of acidity or alkalinity of a soil. Corrosion Potential
Resistivity
Used to indicate the relative ability of a soil medium to carry
electrical currents. Corrosion Potential
R-Value
Used to evaluate the potential strength of subgrade soil,
subbase, and base course material, including recycled
materials for use in road and airfield pavements.
Pavement Thickness
Design
Soluble Sulfate
Used to determine the quantitative amount of soluble
sulfates within a soil mass. Corrosion Potential
Unconfined
Compression
To obtain the approximate compressive strength of soils that
Exhibit C-5
REPORT TERMINOLOGY
(Based on ASTM D653)
Allowable Soil
Bearing Capacity
The recommended maximum contact stress developed at the interface of the foundation
element and the supporting material.
Alluvium
Soil, the constituents of which have been transported in suspension by flowing water and
subsequently deposited by sedimentation.
Aggregate Base
Course
A layer of specified material placed on a subgrade or subbase usually beneath slabs or
pavements.
Backfill A specified material placed and compacted in a confined area.
Bedrock
A natural aggregate of mineral grains connected by strong and permanent cohesive forces.
Usually requires drilling, wedging, blasting or other methods of extraordinary force for
excavation.
Bench A horizontal surface in a sloped deposit.
Caisson (Drilled
Pier or Shaft)
A concrete foundation element cast in a circular excavation which may have an enlarged base.
Sometimes referred to as a cast-in-place pier or drilled shaft.
Coefficient of
Friction
A constant proportionality factor relating normal stress and the corresponding shear stress at
which sliding starts between the two surfaces.
Colluvium
Soil, the constituents of which have been deposited chiefly by gravity such as at the foot of a
slope or cliff.
Compaction The densification of a soil by means of mechanical manipulation
Concrete Slab-on-
Grade
A concrete surface layer cast directly upon a base, subbase or subgrade, and typically used
as a floor system.
Differential
Movement Unequal settlement or heave between, or within foundation elements of structure.
Earth Pressure The pressure exerted by soil on any boundary such as a foundation wall.
ESAL
Equivalent Single Axle Load, a criteria used to convert traffic to a uniform standard, (18,000
pound axle loads).
Engineered Fill
Specified material placed and compacted to specified density and/or moisture conditions
under observations of a representative of a geotechnical engineer.
Equivalent Fluid
A hypothetical fluid having a unit weight such that it will produce a pressure against a lateral
support presumed to be equivalent to that produced by the actual soil. This simplified
approach is valid only when deformation conditions are such that the pressure increases
linearly with depth and the wall friction is neglected.
Existing Fill (or
Man-Made Fill) Materials deposited throughout the action of man prior to exploration of the site.
Existing Grade The ground surface at the time of field exploration.
Exhibit C-6
REPORT TERMINOLOGY
(Based on ASTM D653)
Expansive Potential The potential of a soil to expand (increase in volume) due to absorption of moisture.
Finished Grade The final grade created as a part of the project.
Footing A portion of the foundation of a structure that transmits loads directly to the soil.
Foundation The lower part of a structure that transmits the loads to the soil or bedrock.
Frost Depth The depth at which the ground becomes frozen during the winter season.
Grade Beam
A foundation element or wall, typically constructed of reinforced concrete, used to span between
other foundation elements such as drilled piers.
Groundwater Subsurface water found in the zone of saturation of soils or within fractures in bedrock.
Heave Upward movement.
Lithologic The characteristics which describe the composition and texture of soil and rock by observation.
Native Grade The naturally occurring ground surface.
Native Soil Naturally occurring on-site soil, sometimes referred to as natural soil.
Optimum Moisture
Content
The water content at which a soil can be compacted to a maximum dry unit weight by a given
compactive effort.
Perched Water
Groundwater, usually of limited area maintained above a normal water elevation by the
presence of an intervening relatively impervious continuous stratum.
Scarify To mechanically loosen soil or break down existing soil structure.
Settlement Downward movement.
Skin Friction (Side
Shear)
The frictional resistance developed between soil and an element of the structure such as a
drilled pier.
Soil (Earth)
Sediments or other unconsolidated accumulations of solid particles produced by the physical
and chemical disintegration of rocks, and which may or may not contain organic matter.
Strain The change in length per unit of length in a given direction.
Stress The force per unit area acting within a soil mass.
Strip To remove from present location.
Subbase A layer of specified material in a pavement system between the subgrade and base course.
Subgrade The soil prepared and compacted to support a structure, slab or pavement system.
possess sufficient cohesion to permit testing in the
unconfined state.
Bearing Capacity
Analysis for
Foundations
Water Content
Used to determine the quantitative amount of water in a soil
mass.
Index Property Soil
Behavior
C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded
gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly
graded gravel with silt, GP-GC poorly graded gravel with clay.
D Sands with 5 to 12% fines require dual symbols: SW-SM well-graded
sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded
sand with silt, SP-SC poorly graded sand with clay
E Cu = D60/D10 Cc =
10 60
2
30
D x D
(D )
F If soil contains 15% sand, add “with sand” to group name.
G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM.
H If fines are organic, add “with organic fines” to group name.
I If soil contains 15% gravel, add “with gravel” to group name.
J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay.
K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,”
whichever is predominant.
L If soil contains 30% plus No. 200 predominantly sand, add “sandy” to
group name.
M If soil contains 30% plus No. 200, predominantly gravel, add
“gravelly” to group name.
N PI 4 and plots on or above “A” line.
O PI 4 or plots below “A” line.
P PI plots on or above “A” line.
Q PI plots below “A” line.
Silt or Clay
Descriptive Term(s)
of other constituents
N
(HP)
(T)
(DCP)
(PID)
(OVA)
< 15
15 - 29
> 30
Term
PLASTICITY DESCRIPTION
Water levels indicated on the soil boring
logs are the levels measured in the
borehole at the times indicated.
Groundwater level variations will occur
over time. In low permeability soils,
accurate determination of groundwater
levels is not possible with short term water
level observations.
Water Level After
a Specified Period of Time
Water Level After a
Specified Period of Time
Water Initially
Encountered
Modified
Dames &
Moore Ring
Sampler
Standard
Penetration
Test
Unless otherwise noted, Latitude and Longitude are approximately determined using a hand-held GPS device. The accuracy
of such devices is variable. Surface elevation data annotated with +/- indicates that no actual topographical survey was
conducted to confirm the surface elevation. Instead, the surface elevation was approximately determined from topographic
maps of the area.
Standard Penetration Test
Resistance (Blows/Ft.)
Hand Penetrometer
Torvane
Dynamic Cone Penetrometer
Photo-Ionization Detector
Organic Vapor Analyzer
STRENGTH TERMS
Standard Penetration or
N-Value
Blows/Ft.
Descriptive Term
(Consistency)
Descriptive Term
(Density)
CONSISTENCY OF FINE-GRAINED SOILS
(50% or more passing the No. 200 sieve.)
Consistency determined by laboratory shear strength testing, field
visual-manual procedures or standard penetration resistance
Standard Penetration or
N-Value
Blows/Ft.
(More than 50% retained on No. 200 sieve.)
Density determined by Standard Penetration Resistance
RELATIVE DENSITY OF COARSE-GRAINED SOILS
Hard > 30
> 50 Very Stiff 15 - 30
Stiff
Medium Stiff
Very Soft 0 - 1
Medium Dense
Loose Soft
Very Dense
Dense 30 - 50 8 - 15
10 - 29 4 - 8
4 - 9 2 - 4
Very Loose 0 - 3
BORING ID
10 14
6 50
1.5 8 200
1 140
coarse fine
COEFFICIENTS
% COBBLES % GRAVEL % SAND
D30
D10
CC
PERCENT FINER BY WEIGHT
PERCENT COARSER BY WEIGHT
% SILT
100.0
99.31
97.71
95.21
91.66
85.55
67.7
GRAIN SIZE DISTRIBUTION
ASTM D422
CL
1 1/2"
1"
3/4"
1/2"
3/8"
#4
#10
#20
#40
#60
#100
#200
9 - 10.5
PROJECT NUMBER: 20165021
PROJECT: Oakridge Crossing
SITE: Oakridge Drive and McMurry Avenue
Fort Collins, CO
CLIENT: McDermott Properties
Centennial, Colorado
EXHIBIT: B-7
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS 1 20165021.GPJ 35159097 - ATTERBERG ISSUE.GPJ 3/10/16
70
60
50
40
30
20
10
0
REMARKS
COBBLES SILT OR CLAY
GRAVEL SAND
medium
12.0
4.5
U.S. SIEVE NUMBERS
4 4 6 100
3 2
fine coarse
SOIL DESCRIPTION
CU 22.73 22.23
BORING ID
10 14
6 50
1.5 8 200
1 140
coarse fine
COEFFICIENTS
% COBBLES % GRAVEL % SAND
D30
D10
CC
PERCENT FINER BY WEIGHT
PERCENT COARSER BY WEIGHT
% SILT
GRAIN SIZE DISTRIBUTION
ASTM D422
SM
SW
24 - 24.8
9 - 10.5
9 - 10
PROJECT NUMBER: 20165021
PROJECT: Oakridge Crossing
SITE: Oakridge Drive and McMurry Avenue
Fort Collins, CO
CLIENT: McDermott Properties
Centennial, Colorado
EXHIBIT: B-6
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS 1 20165021.GPJ 35159097 - ATTERBERG ISSUE.GPJ 3/10/16
10
0
REMARKS
COBBLES SILT OR CLAY
GRAVEL SAND
medium
43.5
59.1
70.2
U.S. SIEVE NUMBERS
4 4 6 100
3 2
fine coarse
SOIL DESCRIPTION
CU
BORING ID
10 14
6 50
1.5 8 200
1 140
coarse fine
COEFFICIENTS
% COBBLES % GRAVEL % SAND
D30
D10
CC
PERCENT FINER BY WEIGHT
PERCENT COARSER BY WEIGHT
% SILT
92.55
92.55
92.55
90.39
85.82
76.86
67.63
59.57
52.6
43.5
100.0
95.79
95.11
93.29
90.89
86.27
81.46
76.48
69.86
59.12
100.0
99.66
99.39
98.84
97.75
95.37
89.11
70.25
GRAIN SIZE DISTRIBUTION
ASTM D422
SC
CL
CL
1 1/2"
1"
3/4"
1/2"
3/8"
#4
#10
#20
#40
#60
#100
#200
9 - 10.5
4 - 5
14 - 15.5
PROJECT NUMBER: 20165021
PROJECT: Oakridge Crossing
SITE: Oakridge Drive and McMurry Avenue
Fort Collins, CO
CLIENT: McDermott Properties
Centennial, Colorado
EXHIBIT: B-5
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS 1 20165021.GPJ 35159097 - ATTERBERG ISSUE.GPJ 3/10/16
20
10
0
REMARKS
COBBLES SILT OR CLAY
GRAVEL SAND
medium
66.7
95.7
U.S. SIEVE NUMBERS
4 4 6 100
3 2
fine coarse
SOIL DESCRIPTION
CU
BORING ID
10 14
6 50
1.5 8 200
1 140
coarse fine
COEFFICIENTS
% COBBLES % GRAVEL % SAND
D30
D10
CC
PERCENT FINER BY WEIGHT
PERCENT COARSER BY WEIGHT
% SILT
GRAIN SIZE DISTRIBUTION
ASTM D422
CL
CH
4 - 5
19 - 20.5
4 - 5
PROJECT NUMBER: 20165021
PROJECT: Oakridge Crossing
SITE: Oakridge Drive and McMurry Avenue
Fort Collins, CO
CLIENT: McDermott Properties
Centennial, Colorado
EXHIBIT: B-4
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS 1 20165021.GPJ 35159097 - ATTERBERG ISSUE.GPJ 3/10/16
70
60
50
40
30
20
10
0
REMARKS
COBBLES SILT OR CLAY
GRAVEL SAND
medium
31.5
10.9
U.S. SIEVE NUMBERS
4 4 6 100
3 2
fine coarse
SOIL DESCRIPTION
CU 2.54
BORING ID
10 14
6 50
1.5 8 200
1 140
coarse fine
COEFFICIENTS
% COBBLES % GRAVEL % SAND
D30
D10
CC
PERCENT FINER BY WEIGHT
PERCENT COARSER BY WEIGHT
% SILT
100.0
99.45
80.7
70.0
56.93
100.0
99.05
95.46
90.53
81.46
70.22
57.27
45.7
31.47
100.0
99.76
98.44
96.88
92.2
36.78
10.86
GRAIN SIZE DISTRIBUTION
ASTM D422
SC
SP-SM
1 1/2"
1"
3/4"
1/2"
3/8"
#4
#10
#20
#40
#60
#100
#200
2 - 3.5
9 - 10.5
19 - 19.5
PROJECT NUMBER: 20165021
PROJECT: Oakridge Crossing
SITE: Oakridge Drive and McMurry Avenue
Fort Collins, CO
CLIENT: McDermott Properties
Centennial, Colorado
EXHIBIT: B-3
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS 1 20165021.GPJ 35159097 - ATTERBERG ISSUE.GPJ 3/10/16
23
13
17
15
NP
13
15
14
9
28
18
22
15
NP
12
21
31
67
96
44
59
70
12
4
68
LL USCS
2
3
3
4
5
5
5
P1
P3
ATTERBERG LIMITS RESULTS
ASTM D4318
9 - 10.5
4 - 5
19 - 20.5
9 - 10.5
4 - 5
14 - 15.5
24 - 24.8
9 - 10.5
9 - 10.5
PROJECT NUMBER: 20165021
PROJECT: Oakridge Crossing
SITE: Oakridge Drive and McMurry Avenue
Fort Collins, CO
CLIENT: McDermott Properties
Centennial, Colorado
EXHIBIT: B-2
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. ATTERBERG LIMITS 20165021.GPJ TERRACON2015.GDT 3/4/16
CL-ML
SAMPLE TYPE
WATER LEVEL
OBSERVATIONS
DEPTH (Ft.)
5
10
SWELL-CONSOL /
LOAD (%/psf)
FIELD TEST
RESULTS
DEPTH
LOCATION See Exhibit A-2
Latitude: 40.52133196° Longitude: -105.047601°
No free water observed during drilling
No free water measured 3/1/16
WATER LEVEL OBSERVATIONS
WATER LEVEL
OBSERVATIONS
DEPTH (Ft.)
5
10
SWELL-CONSOL /
LOAD (%/psf)
FIELD TEST
RESULTS
DEPTH
LOCATION See Exhibit A-2
Latitude: 40.52070198° Longitude: -105.047747°
No free water observed during drilling
No free water measured 3/1/16
WATER LEVEL OBSERVATIONS
WEIGHT (pcf)
ATTERBERG
LIMITS
LL-PL-PI
Surface Elev.: 100.69 (Ft.)
ELEVATION (Ft.)
SAMPLE TYPE
WATER LEVEL
OBSERVATIONS
DEPTH (Ft.)
5
10
SWELL-CONSOL /
LOAD (%/psf)
FIELD TEST
RESULTS
DEPTH
LOCATION See Exhibit A-2
Latitude: 40.52077901° Longitude: -105.048449°
No free water observed during drilling
No free water measured 3/1/16
WATER LEVEL OBSERVATIONS
See Exhibit A-3 for description of field procedures.
See Appendix B for description of laboratory
procedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.
PROJECT: Oakridge Crossing
UNCONFINED
COMPRESSIVE
STRENGTH (psf)
PERCENT FINES
WATER
CONTENT (%)
DRY UNIT
WEIGHT (pcf)
ATTERBERG
LIMITS
LL-PL-PI
Surface Elev.: 100.96 (Ft.)
ELEVATION (Ft.)
SAMPLE TYPE
WATER LEVEL
OBSERVATIONS
DEPTH (Ft.)
5
10
15
20
SWELL-CONSOL /
LOAD (%/psf)
FIELD TEST
RESULTS
DEPTH
LOCATION See Exhibit A-2
Latitude: 40.52117698° Longitude: -105.047385°
No free water observed during drilling
Water level on 3/1/16
WATER LEVEL OBSERVATIONS
UNCONFINED
COMPRESSIVE
STRENGTH (psf)
PERCENT FINES
WATER
CONTENT (%)
DRY UNIT
WEIGHT (pcf)
ATTERBERG
LIMITS
LL-PL-PI
Surface Elev.: 100.02 (Ft.)
ELEVATION (Ft.)
SAMPLE TYPE
WATER LEVEL
OBSERVATIONS
DEPTH (Ft.)
5
10
15
20
SWELL-CONSOL /
LOAD (%/psf)
FIELD TEST
RESULTS
DEPTH
LOCATION See Exhibit A-2
Latitude: 40.52084598° Longitude: -105.04755°
While drilling
Water level on 3/1/16
WATER LEVEL OBSERVATIONS
Exhibit: A-6
See Exhibit A-3 for description of field procedures.
See Appendix B for description of laboratory
procedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.
PROJECT: Oakridge Crossing
UNCONFINED
COMPRESSIVE
STRENGTH (psf)
PERCENT FINES
WATER
CONTENT (%)
DRY UNIT
WEIGHT (pcf)
ATTERBERG
LIMITS
LL-PL-PI
Surface Elev.: 99.55 (Ft.)
ELEVATION (Ft.)
SAMPLE TYPE
WATER LEVEL
OBSERVATIONS
DEPTH (Ft.)
5
10
15
20
SWELL-CONSOL /
LOAD (%/psf)
FIELD TEST
RESULTS
DEPTH
LOCATION See Exhibit A-2
Latitude: 40.520433° Longitude: -105.047213°
While drilling
Water level on 3/1/16
WATER LEVEL OBSERVATIONS
abbreviations.
PROJECT: Oakridge Crossing
UNCONFINED
COMPRESSIVE
STRENGTH (psf)
PERCENT FINES
WATER
CONTENT (%)
DRY UNIT
WEIGHT (pcf)
ATTERBERG
LIMITS
LL-PL-PI
Surface Elev.: 98.82 (Ft.)
ELEVATION (Ft.)
SAMPLE TYPE
WATER LEVEL
OBSERVATIONS
DEPTH (Ft.)
5
10
15
20
25
SWELL-CONSOL /
LOAD (%/psf)
FIELD TEST
RESULTS
DEPTH
LOCATION See Exhibit A-2
Latitude: 40.52054901° Longitude: -105.047874°
While drilling
Water level on 3/1/16
WATER LEVEL OBSERVATIONS
CONTENT (%)
DRY UNIT
WEIGHT (pcf)
ATTERBERG
LIMITS
LL-PL-PI
Surface Elev.: 100.21 (Ft.)
ELEVATION (Ft.)
SAMPLE TYPE
WATER LEVEL
OBSERVATIONS
DEPTH (Ft.)
5
10
15
20
SWELL-CONSOL /
LOAD (%/psf)
FIELD TEST
RESULTS
DEPTH
LOCATION See Exhibit A-2
Latitude: 40.52041498° Longitude: -105.048557°
While drilling
Water level on 3/1/16
WATER LEVEL OBSERVATIONS