HomeMy WebLinkAboutSCOTT PLAZA - FDP - FDP140004 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTGeotechnical Engineering Report
Proposed Student Housing
Scott Avenue and West Plum Street
Fort Collins, Colorado
September 18, 2013
Terracon Project No. 20135030
Prepared for:
Taylor Fitzpatrick Capital, Inc.
Scottsdale, Arizona
Prepared by:
Terracon Consultants, Inc.
Fort Collins, Colorado
TABLE OF CONTENTS
Page
EXECUTIVE SUMMARY ............................................................................................................ i
1.0 INTRODUCTION .............................................................................................................1
2.0 PROJECT INFORMATION .............................................................................................2
2.1 Project Description ...............................................................................................2
2.2 Site Location and Description...............................................................................3
3.0 SUBSURFACE CONDITIONS ........................................................................................3
3.1 Typical Subsurface Profile ...................................................................................3
3.2 Laboratory Testing ...............................................................................................4
3.3 Groundwater ........................................................................................................4
4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION ......................................4
4.1 Geotechnical Considerations ...............................................................................4
4.1.1 Existing, Undocumented Fill .....................................................................5
4.1.2 Shallow Groundwater ...............................................................................5
4.1.3 Expansive Soils ........................................................................................5
4.2 Earthwork.............................................................................................................5
4.2.1 Demolition ................................................................................................6
4.2.2 Site Preparation ........................................................................................6
4.2.3 Excavation ................................................................................................6
4.2.4 Subgrade Preparation ...............................................................................7
4.2.5 Fill Materials and Placement ......................................................................7
4.2.6 Compaction Requirements ........................................................................9
4.2.7 Utility Trench Backfill .................................................................................9
4.2.8 Grading and Drainage .............................................................................10
4.2.9 Exterior Slab Design and Construction .....................................................11
4.2.10 Corrosion Protection ................................................................................11
4.3 Foundations .......................................................................................................11
4.3.1 Drilled Piers Bottomed in Bedrock - Design Recommendations ..............11
4.3.2 Drilled Piers Bottomed in Bedrock - Construction Considerations ...........12
4.4 Seismic Considerations......................................................................................13
4.5 Floor Systems ....................................................................................................13
4.5.1 Floor System - Design Recommendations ..............................................13
4.5.2 Floor Systems - Construction Considerations .........................................14
4.6 Lateral Earth Pressures .....................................................................................15
4.7 Hydraulic Conductivity Testing .................................................................................16
4.7.1 Hydraulic Conductivity – Field Investigation ............................................16
4.7.2 Hydraulic Conductivity - Discussion ........................................................17
4.8 Pavements .........................................................................................................17
4.8.1 Pavements – Conventional Subgrade Preparation .................................17
4.8.2 Pavements – Permeable Pavers Subgrade Preparation .........................18
4.8.3 Pavements – Design Recommendations ................................................18
4.8.4 Pavements – Maintenance .....................................................................20
5.0 GENERAL COMMENTS ...............................................................................................21
TABLE OF CONTENTS (continued)
Appendix A – FIELD EXPLORATION
Exhibit A-1 Site Location Map
Exhibit A-2 Boring Location Plan
Exhibit A-3 Field Exploration Description
Exhibits A-4 to A-9 Boring Logs
Appendix B – LABORATORY TESTING
Exhibit B-1 Laboratory Testing Description
Exhibit B-2 Atterberg Limits Test Results
Exhibits B-3 Grain-size Distribution Test Results
Exhibits B-4 to B-5 Swell-consolidation Test Results
Exhibit B-6 Field Hydraulic Conductivity 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
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
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EXECUTIVE SUMMARY
A geotechnical investigation has been performed for the proposed Student Housing project to be
constructed southwest of the intersection of Scott Avenue and West Plum Street in Fort Collins,
Colorado. Four (4) borings, presented as Exhibits A-4 through A-7 and designated as Boring No.
1 through Boring No. 4, were performed to depths of approximately 10 to 30 feet below existing site
grades. Additionally, two (2) field hydraulic conductivity tests, presented as exhibits A-8 and A-9
and designated as Boring Nos. H-1 and H-2, were performed to depths of approximately 5 feet
below existing site grades. This report specifically addresses the recommendations for the
proposed building and associated pavements. 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:
Existing, undocumented fill was encountered in the borings performed on this site to depths
of about 3 feet below existing site grades. The existing fill soils should be removed and
replaced with engineered fill beneath proposed pavements and floor slabs.
Samples of the site soils selected for swell/consolidation testing exhibited slight
compression to 3.7 percent swell when wetted. The lean clay soils are considered low
swelling and were encountered at anticipated foundation levels in the southern portion of
the site during our field investigation.
The proposed building may be supported on a drilled pier foundation system bottomed in
bedrock.
Considering the low swelling soils encountered in our borings on the northern portion of
the site where floor slabs may be constructed, we believe a slab-on-grade floor system
may be used for the proposed building provided about 1 inch of movement can be
tolerated. If the estimated movement cannot be tolerated, structural floors, supported
independent of the subgrade materials, are recommended.
It is our understanding that the existing structures on the site will be razed. Based on
our site observations, some of the existing structures have basement construction. Care
should be taken during site preparation to include complete removal of the foundation
systems and basements as well as backfilling the resulting excavations within the
proposed construction areas.
The 2009 International Building Code, Table 1613.5.2 IBC seismic site classification for this
site is C.
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Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
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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
Proposed Student Housing
Scott Avenue and West Plum Street
Fort Collins, Colorado
Terracon Project No. 20135030
September 18, 2013
1.0 INTRODUCTION
This report presents the results of our geotechnical engineering services performed for the
proposed Student Housing to be located at the southwest corner of the intersection of Scott
Avenue and West Plum Street in Fort Collins, Colorado. The purpose of these services is to
provide information and geotechnical engineering recommendations relative to:
subsurface soil and bedrock conditions foundation design and construction
groundwater conditions floor slab design and construction
grading and drainage pavement construction
lateral earth pressures earthwork
seismic considerations
Our geotechnical engineering scope of work for this project included the initial site visit, the
advancement of six test borings to depths ranging from approximately 5 to 30 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 a Boring Location 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.
Previously, Terracon prepared a Geotechnical Engineering Report (Project No. 20085059; report
dated August 21, 2008) for a proposed student housing project that included completion of two (2)
borings on this project site. We also prepared a Geotechnical Engineering Report (Project No.
20115026; report dated November 2, 2011) and Addendum No. 1 (report dated October 29, 2012)
for The District at CSU (a.k.a. The District at Campus West) project located directly north of this
site. The services performed for this current study were completed to supplement the
geotechnical data previously obtained on and near this site.
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
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2.0 PROJECT INFORMATION
2.1 Project Description
Item Description
Site layout Refer to the Boring Location Plan (Exhibit A-2 in Appendix A)
Structures We understand a 4 to 5-story multi-family apartment building is
planned for this site.
Building construction
Final design of the proposed building was not available at the time
this report was submitted. We anticipate the proposed building will
be constructed with reinforced concrete support members, wood or
steel framing, and reinforced concrete deck floors.
Finished floor elevation
We anticipate the finished floor elevations for the proposed
buildings will be slightly above existing site grades. Depending on
the final design, the lower level parking areas may extend up to 8
or 15 feet below grade.
Maximum loads
Building:
Column Loads: 40 kips max (assumed)
Wall loads: 4 to 5 klf max (assumed)
Slab-on-grade: 150 psf max (assumed)
Grading in building area
We assume cuts and fills on the order of 5 feet or less will be
required for the construction of the proposed building. Deeper cuts
and fills may be necessary for the demolition of existing site
features, installation of new utilities, and deeper lower level parking
areas.
Grading in parking area
Preliminary designs indicate pavement areas will slope from the
north to the south to facilitate infiltration of storm water to areas
planned for permeable pavements.
Traffic loading
The portion of Scott Avenue proposed to be reconstructed is
categorized by the Larimer County Urban Area Street Standards
(LCUASS) as a residential, two-lane road with an Estimated Daily
Load Application (EDLA) of 5 and a design life of 20-years.
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2.2 Site Location and Description
Item Description
Location The project site is located southwest of the intersection of Scott
Avenue and West Plum Street in Fort Collins, Colorado.
Existing site features
The site is currently occupied by single-family residential and retail
buildings. Paved parking occupies a portion of the site with
landscaped areas and mature trees on a portion of the property.
The surrounding roadways are paved with asphalt and concrete
with curb and gutter.
Surrounding developments
The site is bordered to the north, east, and west by multi-family
residential housing. Commercial retail borders the site to the
south.
Existing topography The site slopes down from the north to the south.
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
Fill materials consisting of lean clay,
silt, sand, and gravel
About 3 below existing site
grades in Boring Nos. 2, 3, and
H-1 only.
--
Sand with silt, clay, and gravel
About 6 to 14½ feet below
existing site grades.
Loose to medium dense
Lean clay
About 6 feet below existing site
grades in Boring No. 4 and H-2
only.
Very stiff
Poorly-graded gravel with sand
About 8 to 15.5 feet below
existing site grades.
--
Claystone bedrock
To the maximum depth of
exploration of about 30 feet.
Hard to very hard
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Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
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3.2 Laboratory Testing
Representative soil samples were selected for swell-consolidation testing and exhibited slight
compression to 3.7 percent swell when wetted. Samples of site soils and bedrock selected for
plasticity testing exhibited low to medium plasticity with liquid limits ranging from 21 to 35 and
plasticity indices ranging from 3 to 21. Laboratory test results are presented in Appendix B.
3.3 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
1 day after drilling, ft.
Elevation of
groundwater 8 days
after drilling, ft.
1 11 11.5 89.7
2 13 12.9 89.2
3 Not encountered Backfilled after drilling Backfilled after drilling
4 7 7.2 89.2
H-1 Not encountered Not encountered Not encountered
H-2 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 in the amount of rainfall, runoff
and other factors not evident at the time the borings were performed. Therefore, groundwater
levels during construction or at other times in the life of the structure may be higher or lower
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.
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
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
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identified geotechnical conditions that could impact design and construction of the proposed
structure, pavements, and other site improvements.
4.1.1 Existing, Undocumented Fill
As previously noted, existing undocumented fill was encountered to depths up to about 3 feet in
the borings drilled at the site. Deeper fills are likely present where existing basements and
buried utilities are present. We do not possess any information regarding whether the fill was
placed under the observation of a geotechnical engineer.
Support of floor slabs and pavements on or above existing fill soils is discussed in this report.
However, even with the recommended construction testing services, there is an inherent risk for
the owner that compressible fill or unsuitable material within or buried by the fill will not be
discovered. This risk of unforeseen conditions cannot be eliminated without completely
removing the existing fill, but can be reduced by performing additional testing and evaluation.
4.1.2 Shallow Groundwater
As previously stated, groundwater was measured at depths ranging from about 7.2 to 12.9 feet
below existing site grades. Terracon recommends maintaining a separation of at least 3 feet
between the bottom of proposed site improvements and measured groundwater levels. If
below-grade parking areas are planned for this project, construction and permanent dewatering
will be necessary for improvements extending into groundwater. It is also possible and likely
that groundwater levels below this site may rise.
4.1.3 Expansive Soils
Laboratory testing indicates the native clay soils exhibited up to 3.7 percent swell 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 is generally not be 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.
4.2 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
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
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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 Demolition
Demolition of the existing buildings should include complete removal of all foundation systems,
below-grade structural elements, pavements, and exterior flatwork within the proposed
construction area. This should include removal of any utilities to be abandoned along with any
loose utility trench backfill or loose backfill found adjacent to existing foundations. All materials
derived from the demolition of existing structures and pavements should be removed from the
site. The types of foundation systems supporting the existing structures are not known. If some or
all of the existing buildings are supported by drilled piers, the existing piers should be truncated a
minimum depth of 3 feet below areas of planned new construction.
Consideration could be given to re-using the concrete provided the materials are processed and
uniformly blended with the on-site soils. Concrete materials should be processed to a maximum
size of 2-inches and blended at a ratio of 30 percent concrete to 70 percent of on-site soils.
4.2.2 Site Preparation
Prior to placing any fill, strip and remove existing vegetation, the full depth of undocumented
existing fill, 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.
4.2.3 Excavation
It is anticipated that excavations for the proposed construction can be accomplished with
conventional earthmoving equipment. Demolition of existing site features will require specialized
excavation equipment.
The soils to be excavated 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.
Although evidence of underground facilities such as septic tanks and vaults 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.
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
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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. Well points may be required for
significant groundwater flow, or where excavations penetrate groundwater to a significant depth.
Groundwater seepage should be anticipated for excavations approaching the level of bedrock.
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.
4.2.4 Subgrade Preparation
After completion of demolition and the existing fill and deleterious materials have been removed
from the construction area, 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, foundation, or pavement is placed.
The exposed subgrade below portions of this site to receive permeable pavements should not
be compacted. If the soil below portions of the site to receive permeable pavements is
compacted, the calculated hydraulic conductivity may be reduced and infiltration of water may
be lower than anticipated.
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 section 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
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.
4.2.5 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,
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
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as defined by a field technician who is qualified in soil material identification and compaction
procedures, can be re-used as fill for the floor slabs and pavement subgrade. It should be
noted that on-site soils will 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 Value
Liquid Limit 30 (max.)
Plastic Limit 15 (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.
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4.2.6 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
Moisture content cohesive soil (clay) -1 to +3 % of the optimum moisture content
Moisture content cohesionless soil
(sand)
-3 to +2 % 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.
4.2.7 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
in foundation walls 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 building (if any) should be effectively sealed to restrict water intrusion and
flow through the trenches that could migrate below the building. We recommend constructing an
effective clay “trench plug” that extends at least 5 feet out from the face of the building exterior.
The plug material should consist of clay compacted at a water content at or above the soil’s
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
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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.
4.2.8 Grading and Drainage
All grades must be adjusted to provide effective drainage away from the proposed building and
pavements 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 structure (either during or post-
construction) can result in significantly higher 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 building, 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 building. Backfill against footings 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 building 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
structure, care should be taken that joints are properly sealed and maintained to prevent the
infiltration of surface water.
Planters located adjacent to structure 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 structure 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.
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
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4.2.9 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:
Minimizing moisture increases in the backfill;
Controlling moisture-density during placement of the backfill;
Using designs which allow vertical movement between the exterior features
and adjoining structural elements; and
Placing control joints on relatively close centers.
4.2.10 Corrosion Protection
Results of water-soluble sulfate testing indicate that ASTM Type I or II portland cement should
be specified for all project concrete on and below grade. Foundation concrete should be
designed for low sulfate exposure in accordance with the provisions of the ACI Design Manual,
Section 318, Chapter 4.
4.3 Foundations
The proposed building may be supported by a drilled pier foundation system bottomed in
bedrock.
4.3.1 Drilled Piers Bottomed in Bedrock - Design Recommendations
Description Value
Minimum pier length 25 feet
Minimum pier diameter 18 inches
Minimum bedrock embedment 1 10 feet
Maximum allowable end-bearing pressure 30,000 psf
Allowable skin friction (for portion of pier embedded into bedrock) 2,500 psf
Void thickness (beneath grade beams) 4 inches
1. Drilled piers should be embedded into hard or very hard bedrock materials.
Site grading details were not fully understood at the time we prepared this report. If significant
fills are planned in the proposed building areas, longer drilled pier lengths may be required.
Piers should be considered to work in group action if the horizontal spacing is less than three
pier diameters. A minimum practical horizontal clear spacing between piers of at least three
diameters should be maintained, and adjacent piers should bear at the same elevation. The
capacity of individual piers must be reduced when considering the effects of group action.
Capacity reduction is a function of pier spacing and the number of piers within a group. If group
action analyses are necessary, capacity reduction factors can be provided for the analyses.
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
Responsive Ŷ Resourceful Ŷ Reliable 12
To satisfy forces in the horizontal direction using LPILE, piers may be designed for the following
lateral load criteria:
Parameters Clay Sand and
Gravel
Claystone
Bedrock
LPILE soil type1
Stiff clay
without free
water
Sand
(submerged)
Stiff clay
without free
water
Unit weight (pcf) 120 125 130
Average undrained shear strength (psf) 500 N/A 9,000
Average angle of internal friction, ) (degrees) N/A 35 N/A
Coefficient of subgrade reaction, k (pci)*
100 - static
30 - cyclic
60
2,000- static
800 – cyclic
Strain, H50 (%) 0.010 N/A 0.004
1. For purposes of LPILE analysis, assume a groundwater depth of about 12 feet below existing
ground surface (approximately Elev. 89.0 feet).
4.3.2 Drilled Piers Bottomed in Bedrock - Construction Considerations
Drilling to design depth should be possible with conventional single-flight power augers on the
majority of the site; however, specialized drilling equipment may be required for very hard bedrock
layers. In addition, possible caving soils and groundwater indicate that temporary steel casing
may be required to properly drill the piers prior to concrete placement.
Groundwater should be removed from each pier hole prior to concrete placement. Pier concrete
should be placed immediately after completion of drilling and cleaning. If pier concrete cannot
be placed in dry conditions, a tremie should be used for concrete placement. The use of a
bottom-dump hopper, or an elephant's trunk discharging near the bottom of the hole where
concrete segregation will be minimized, is recommended. Due to potential sloughing and
raveling, foundation concrete quantities may exceed calculated geometric volumes.
Casing should be withdrawn in a slow continuous manner maintaining a sufficient head of
concrete to prevent infiltration of water or caving soils or the creation of voids in pier concrete.
Pier concrete should have a relatively high fluidity when placed in cased pier holes or through a
tremie. Pier concrete with slump in the range of 5 to 7 inches is recommended.
We recommend the sides of each pier should be mechanically roughened in the claystone
bearing strata. This should be accomplished by a roughening tooth placed on the auger. Shaft
bearing surfaces must be cleaned prior to concrete placement. A representative of the
Terracon should observe the bearing surface and shaft configuration.
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
Responsive Ŷ Resourceful Ŷ Reliable 13
4.4 Seismic Considerations
Code Used Site Classification
2009 International Building Code (IBC) 1 C 2
1. In general accordance with the 2009 International Building Code, Table 1613.5.2.
2. The 2009 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 30 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 Floor Systems
Discussions with other design members indicate the northern portion of the building may be built
on-grade. A slab-on-grade may be utilized for the interior floor system for the proposed building
provided the recommendations of section 4.2 Earthwork of this report are followed. If the
estimated movement cannot be tolerated, a structurally-supported floor system, supported
independent of the subgrade materials, is recommended.
Prior to the construction of slabs-on-grade, remove the undocumented existing fill, the subgrade
soils beneath interior and exterior slabs should be scarified to a depth of at least 8 inches,
moisture conditioned and compacted. The moisture content and compaction of subgrade soils
should be maintained until slab construction.
Swelling lean clay soils were encountered on the southern portion of this site. If clay soils are
encountered during the excavation and/or construction of the slab-on-grade floor system, the
clay soils will need to be over-excavated a minimum of 2 feet, the bottom of the over-excavation
will need to be scarified and compacted as presented in section 4.2.4 Subgrade Preparation
section of this report, and the clay soils must be replaced with engineered fill as presented in
4.2.5 Fill Materials and Placement section of this report.
4.5.1 Floor System - Design Recommendations
Even when bearing on properly prepared soils, movement of the slab-on-grade floor system is
possible should the subgrade soils undergo an increase in moisture content. We estimate
movement of about 1 inch is possible.
For structural design of concrete slabs-on-grade subjected to point loadings, a modulus of
subgrade reaction of 100 pounds per cubic inch (pci) may be used for floors supported on re-
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
Responsive Ŷ Resourceful Ŷ Reliable 14
compacted existing soils at the site. A modulus of 200 pci may be used for floors supported on
at least 1 foot of non-expansive, imported granular fill.
Additional floor slab design and construction recommendations are as follows:
Positive separations and/or isolation joints should be provided between slabs and all
foundations, columns, or utility lines to allow independent movement.
Control joints should be saw-cut in slabs in accordance with ACI Design Manual,
Section 302.1R-37 8.3.12 (tooled control joints are not recommended) to control the
location and extent of cracking.
Interior utility trench backfill placed beneath slabs should be compacted in accordance
with the recommendations presented in the 4.2 Earthwork section of this report.
Floor slabs should not be constructed on frozen subgrade.
A minimum 2-inch void space should be constructed below non-bearing partition walls
placed on the floor slab. Special framing details should be provided at doorjambs and
frames within partition walls to avoid potential distortion. Partition walls should be
isolated from suspended ceilings.
The use of a vapor retarder should be considered beneath concrete slabs that will be
covered with wood, tile, carpet or other moisture sensitive or impervious floor
coverings, or when the slab will support equipment sensitive to moisture. When
conditions warrant the use of a vapor retarder, the slab designer and slab contractor
should refer to ACI 302 for procedures and cautions regarding the use and placement
of a vapor retarder.
Other design and construction considerations, as outlined in the ACI Design Manual,
Section 302.1R are recommended.
4.5.2 Floor Systems - Construction Considerations
Movements of slabs-on-grade using the recommendations discussed in previous sections of this
report will likely be reduced and tend to be more uniform. The estimates discussed above
assume that the other recommendations in this report are followed. Additional movement could
occur should the subsurface soils become wetted to significant depths, which could result in
potential excessive movement causing uneven floor slabs and severe cracking. This could be
due to over watering of landscaping, poor drainage, improperly functioning drain systems,
and/or broken utility lines. Therefore, it is imperative that the recommendations presented in
this report be followed.
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
Responsive Ŷ Resourceful Ŷ Reliable 15
4.6 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.
EARTH PRESSURE COEFFICIENTS
Earth Pressure
Conditions
Coefficient for
Backfill Type
Equivalent Fluid
Density (pcf)
Surcharge
Pressure,
p1 (psf)
Earth
Pressure,
p2 (psf)
Active (Ka)
Granular - 0.33
Lean Clay - 0.42
40
50
(0.33)S
(0.42)S
(40)H
(50)H
At-Rest (Ko)
Granular - 0.46
Lean Clay - 0.58
55
70
(0.46)S
(0.58)S
(55)H
(70)H
Passive (Kp)
Granular - 3.0
Lean Clay - 2.4
360
288
---
---
---
---
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
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Applicable conditions to the above include:
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;
For passive earth pressure to develop, wall must move horizontally to mobilize resistance;
Uniform surcharge, where S is surcharge pressure;
In-situ soil backfill weight a maximum of 120 pcf;
Horizontal backfill, compacted between 95 and 98 percent of maximum dry unit weight as
determined by ASTM D698;
Loading from heavy compaction equipment not included;
No hydrostatic pressures acting on wall;
No dynamic loading;
No safety factor included in soil parameters; and
Ignore passive pressure in frost zone.
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.
4.7 Hydraulic Conductivity Testing
During our field investigation, two (2) field hydraulic conductivity test borings were completed to
a depth of approximately 5 feet below existing site grades. The field hydraulic conductivity test
borings were completed in areas of the site planned for permeable pavements. One of the field
hydraulic conductivity test borings (H-1) was completed in the area of the existing Scott Avenue.
The second field hydraulic conductivity test boring (H-2) was completed in the southern portion
of the site where we believe an existing detention area is present. Logs of the borings (Exhibits
A-8 and A-9) along with a Boring Location Plan (Exhibit A-2) are included in Appendix A.
4.7.1 Hydraulic Conductivity – Field Investigation
Field hydraulic conductivity test borings were drilled with a CME-55 truck mounted drill rig with 4-
inch outer diameter solid-stem augers. During the drilling operations, lithologic logs of the borings
were recorded by the field engineer. Slotted PVC pipe was placed in each of the field hydraulic
conductivity test holes full-depth and the annulus surrounding the slotted PVC pipe was filled with
clean filter sand. The borings were then saturated with water and left to stabilize for several days.
The soils encountered in H-1 were visually classified in the field and consisted of existing fill
materials comprised of clayey sand with gravel. The existing fill was slightly moist to moist. The
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
Responsive Ŷ Resourceful Ŷ Reliable 17
soils encountered in H-2 were also visually classified in the field and consisted of lean clay with
a trace of gravel. The soils encountered in H-2 were also slightly moist to moist.
Groundwater was not encountered in the field hydraulic conductivity test borings. During
delayed groundwater measurements taken in other borings completed on the site, groundwater
was measured in Boring No. 2 (located near hydraulic conductivity test boring H-1) at a depth of
12.9 feet and Boring No. 4 (located near hydraulic conductivity test boring H-2) at a depth of
approximately 7.2 feet below the existing ground surface. The groundwater levels measured in
our borings at the time of our field study were used when calculating the field hydraulic
conductivity at this site.
4.7.2 Hydraulic Conductivity - Discussion
The field hydraulic conductivity testing performed as part of our study was developed by the
U.S. Bureau of Reclamation and was referred to as the well permeameter method. The field
hydraulic conductivity tests were performed by adding water to the test holes to maintain a
constant water level (constant head test). The calculated hydraulic conductivity value for field
hydraulic conductivity test holes H-1 and H-2 were 19 feet per day (ft/day) and 5 ft/day,
respectively. The calculated values for each test are within the expected ranges for the soil
types encountered in our borings and are considered to be representative values. The
calculated value for the hydraulic conductivity test in test hole H-2 is the limiting hydraulic
conductivity. The size of the rock reservoir and/or storage tank should be determined using the
lower hydraulic conductivity calculated in test hole H-2. The test results and schematics of the
field hydraulic conductivity test hole details are included in Appendix B.
The field hydraulic conductivity test results and soils encountered in our borings completed at
the site indicate infiltration of storm water retained in a reservoir below permeable pavements
into the soils underlying this site will be favorable for the design of permeable pavements.
However, shallow groundwater conditions may limit the allowable depth of the retention area
below permeable pavements. The slotted PVC pipe was left in place for future groundwater
readings.
4.8 Pavements
4.8.1 Pavements – Conventional 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 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. The subgrade should be carefully evaluated
at the time of pavement construction for signs of disturbance or instability. We recommend the
pavement subgrade for conventional pavements be thoroughly proofrolled with a loaded
tandem-axle dump truck prior to final grading and paving. All conventional pavement areas
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
Responsive Ŷ Resourceful Ŷ Reliable 18
should be moisture conditioned and properly compacted to the recommendations in this report
immediately prior to paving.
Samples of the on-site lean clay soils selected for swell-consolidation testing swelled
approximately 3.7 percent when wetted under an applied pressure of 200 psf which is greater
than the maximum 2 percent criteria established for determining if swell-mitigation procedures in
the pavement sections are required per LCUASS standards. Movements up to approximately 2
inches are possible for pavements constructed on the lean clay soils encountered on this site.
Where lean clay soils are present at pavement subgrade areas for conventional pavements, we
recommend over-excavating a minimum of 2 feet below proposed conventional pavements,
scarifying the exposed subgrade and replacing with engineered fill as presented in section 4.2
Earthwork of this report.
4.8.2 Pavements – Permeable Pavers Subgrade Preparation
Unlike conventional pavements, porous pavement subgrades are not compacted. When
preparing the subgrade for porous pavements, care should be taken to excavate the required
reservoir storage volume without disturbing the underlying soils. It may be prudent to scarify the
subgrade soils prior to placement of the materials for the rock reservoir.
Final site grading plans were not available at the time this report was prepared, we estimate
movements on the order of 2 inches are possible for permeable pavers planned for this site.
Conventional swell mitigation techniques such as over-excavation, moisture conditioning, and
recompaction of the clay subgrade soils will negatively affect infiltration rates below permeable
pavers. To reduce the possibility for movements due to swelling soils, we recommend removing
the lean clay soils directly below the elevation of the rock reservoir to a depth of at least 2 feet
and replacing with non-expansive granular fill or extending the rock reservoir to the lower
elevation.
Groundwater was encountered at depths of about 7.2 and 12.9 feet below existing site grades in
the portion of the site planned for porous pavers. Shallow groundwater will reduce infiltration
rates as the water stored within the rock reservoir layer infiltrates into the ground.
4.8.3 Pavements – Design Recommendations
Design of pavements for the project have been based on the procedures outlined in the 1993
Guideline for Design of Pavement Structures prepared by the American Association of State
Highway and Transportation Officials (AASHTO) and the Larimer County Urban Area Street
Standards (LCUASS).
Traffic patterns and anticipated loading conditions were not available at the time that this report
was prepared. However, we anticipate that the new parking areas (i.e., light-duty) will be
primarily used by personal vehicles (cars and pick-up trucks). Delivery trucks and refuse
disposal vehicles will be expected in the drive lanes and loading areas (i.e., medium-duty). A
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
Responsive Ŷ Resourceful Ŷ Reliable 19
maximum of 10 trucks per week were considered developing our recommendations. If heavier
traffic loading is expected, Terracon should be provided with the information and allowed to review
these pavement sections.
Rigid pavement design is based on an evaluation of the Modulus of Subgrade Reaction of the
soils (k-value), the Modulus of Rupture of the concrete, and other factors previously described.
A Modulus of Subgrade Reaction of 200 pci, and a Modulus of Rupture of 600 psi, was used for
pavement concrete. The rigid pavement thickness was determined on the basis of the AASHTO
design equation.
Recommended minimum pavement sections are provided in the table below.
Traffic
Area Alternative
Recommended Pavement Thickness (inches)
Asphaltic
Concrete
(AC)
Aggregate
Base Course
(ABC)
Portland Cement
Concrete
(PCC)
Porous
Pavers Total
Automobile
Parking
(light duty)
A 3 4 - - 7
B - - 5 - 5
C - 3 - ǩ“ ǩ”
Drive Lanes
(medium
duty)
A 4 6 - - 10
B - 4 5 -
9
Terracon recommends the design and construction of porous pavers should be completed by a
specialty contractor who has demonstrated experience with placing, compacting, finishing,
edging, jointing, and protecting porous pavers. There are several choices for base course
depending upon which type of porous paver is chosen. Terracon recommends constructing
perimeter curbing around porous pavers and between conventional and porous pavers to
reduce infiltration of water below moisture sensitive subgrades.
Where rigid pavements are used, portland cement 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 cement
Entrained air content (%) 5 to 8
Concrete aggregate ASTM C33 and CDOT Section 703
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
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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.
Although not required for structural support, a minimum 4-inch thick aggregate base course
layer is recommended for the PCC pavements in medium duty areas to help reduce the
potential for slab curl, shrinkage cracking, and subgrade “pumping” through joints. Proper joint
spacing will also be required for PCC pavements to prevent excessive slab curling and
shrinkage cracking. All joints should be sealed to prevent entry of foreign material and dowelled
where necessary for load transfer.
For areas subject to concentrated and repetitive loading conditions such as 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.
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:
Site grades should slope a minimum of 2 percent away from the pavements;
The subgrade and the pavement surface have a minimum 2 percent slope to promote proper
surface drainage;
Consider appropriate edge drainage and pavement under drain systems;
Install pavement drainage surrounding areas anticipated for frequent wetting;
Install joint sealant and seal cracks immediately;
Seal all landscaped areas in, or adjacent to pavements to reduce moisture migration to
subgrade soils; and
Placing compacted, low permeability backfill against the exterior side of curb and gutter.
4.8.4 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.
Porous pavers require periodic inspection and cleaning. Consideration should be given to
installing signage to restrict heavily loaded vehicles (i.e. trash trucks, delivery trucks, etc.) from
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
Responsive Ŷ Resourceful Ŷ Reliable 21
driving on porous paver areas. Also, maintenance of porous pavers should be completed by
properly trained workers.
5.0 GENERAL COMMENTS
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 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, 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
A-1
20135030
9/9/2013
EDB
BCJ
EDB
EDB
Not to Scale
Project Manager:
Drawn by:
Checked by:
Approved by:
Project No.
Scale:
File Name:
Date:
Exhibit
Project Site
Student Housing at Scott Ave. and W. Plum St.
Scott Avenue and West Plum Street
1901Colorado Sharp Point Drive, Suite C Fort Collins, Colorado 80525 Fort Collins,
PH. (970) 484-0359 FAX. (970) 484-0454
DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT
INTENDED FOR CONSTRUCTION PURPOSES
1901 Sharp Point Drive, Suite C Fort Collins, Colorado 80521
PH. (970) 484-0359 FAX. (970) 484-0454
A-2
BORING LOCATION PLAN EXHIBIT
Student Housing at Scott Ave and W. Plum St.
Scott Avenue and West Plum Street
Fort Collins, Colorado
Project Manager:
Drawn By:
Check By:
Approved By:
EDB
BCJ
EDB
EDB
Project No.
Scale:
File Name:
Date:
20135030
1”=40’
9/10/2013
0’ 20’ 40’
Approximate Scale
LEGEND
Approximate boring location
1
1
2
3
4
Approximate location of temporary benchmark
(Top of manhole cover– assumed elevation
100.0’)
H-1
H-2
H-1
Approximate field hydraulic conductivity test
location
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
Responsive Ŷ Resourceful Ŷ 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 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-55 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. Disturbed bulk samples were
obtained from auger cuttings. 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
approximately one day after drilling. After subsequent groundwater measurements were
obtained, the borings were backfilled with auger cuttings and sand (if needed). Some
settlement of the backfill may occur and should be repaired as soon as possible.
0.3
14.5
15.0
17.0
29.9
VEGETATIVE LAYER - LANDSCAPED GRASS, 3
inches
WELL GRADED SAND WITH SILT AND GRAVEL
(SW-SM), red to brown, loose to medium dense
POORLY GRADED GRAVEL WITH SAND,
medium dense
WEATHERED SEDIMENTARY BEDROCK -
CLAYSTONE, brown rust to gray
SEDIMENTARY BEDROCK - CLAYSTONE, brown
rust to gray, hard
Boring Terminated at 29.9 Feet
101
86.5
86
84
71.5
12
4
3
17
18
17
17
15
6-5
8-14
5-8
2-9-7
N=16
18-20-30
N=50
21-50/6"
N=71/12"
22-50/5"
N=72/11"
111
21-18-3
See Exhibit A-2
Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic
LOCATION
DEPTH
Latitude: 40.576423° Longitude: -105.098624°
GRAPHIC LOG
THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20135030.GPJ TERRACON2012.GDT 9/16/13
Scott Avenue and West Plum Street
Fort Collins, Colorado
SITE:
While drilling
24-hour measurement
WATER LEVEL OBSERVATIONS
PROJECT: Student Housing at Scott Ave.
& W. Plum St.
Page 1 of 1
Advancement Method:
4-inch solid stem flight auger
3.0
14.5
15.5
17.0
29.4
FILL - SANDY LEAN CLAY WITH GRAVEL, brown
SILTY CLAYEY SAND WITH GRAVEL, red to
brown, loose
POORLY GRADED GRAVEL WITH SAND, dense
WEATHERED SEDIMENTARY BEDROCK -
CLAYSTONE, brown rust to gray
SEDIMENTARY BEDROCK - CLAYSTONE (CL),
brown rust to gray, hard to very hard
Boring Terminated at 29.4 Feet
-0.04
99
87.5
86.5
85
72.5
89
8
7
16
9
13
13
15
9-8
6-6
3-5
8-17-18
N=35
50/12"
N=50/12"
29-50/3"
N=79/9"
50/5"
N=50/5"
110
35-14-21
See Exhibit A-2
Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic
LOCATION
DEPTH
Latitude: 40.576059° Longitude: -105.098246°
GRAPHIC LOG
THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20135030.GPJ TERRACON2012.GDT 9/16/13
Scott Avenue and West Plum Street
Fort Collins, Colorado
SITE:
While drilling
24-hour measurement
WATER LEVEL OBSERVATIONS
PROJECT: Student Housing at Scott Ave.
& W. Plum St.
Page 1 of 1
Advancement Method:
4-inch solid stem flight auger
Abandonment Method:
0.6
3.0
6.0
8.0
10.0
VEGETATIVE LAYER, 7 inches
FILL - SILTY CLAYEY SAND WITH GRAVEL,
brown, medium dense
SILTY CLAYEY SAND WITH GRAVEL (SC-SM),
trace cobbles, red, medium dense
POORLY GRADED GRAVEL WITH SAND, brown
LEAN CLAY, light brown to brown, stiff
Boring Terminated at 10 Feet
101
98.5
95.5
93.5
91.5
13
3
2
17
13-10
11-19
5-8 110
22-16-6
See Exhibit A-2
Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic
LOCATION
DEPTH
Latitude: 40.576168° Longitude: -105.098108°
GRAPHIC LOG
THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20135030.GPJ TERRACON2012.GDT 9/16/13
Scott Avenue and West Plum Street
Fort Collins, Colorado
SITE:
No free water observed while drilling, backfilled upon completion.
WATER LEVEL OBSERVATIONS
PROJECT: Student Housing at Scott Ave.
& W. Plum St.
Page 1 of 1
Advancement Method:
4-inch solid stem flight auger
Abandonment Method:
Borings backfilled with soil cuttings and sand upon
completion.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
Notes:
Project No.: 20135030
Drill Rig: CME-55
Boring Started: 9/3/2013
BORING LOG NO. 3
CLIENT: Taylor Fitzpatrick Capital, Inc.
Scottsdale, Arizona
Driller: Drilling Engineers, Inc.
Boring Completed: 9/3/2013
Exhibit: A-6
See Exhibit A-3 for description of field
procedures.
0.5
6.0
8.0
11.5
12.0
VEGETATIVE LAYER, 6 inches
LEAN CLAY, trace gravel, brown, very stiff
POORLY GRADED GRAVEL WITH SAND
SANDY LEAN CLAY WITH GRAVEL, red brown to
olive, very stiff
SEDIMENTARY BEDROCK - CLAYSTONE, brown
rust to olive
Boring Terminated at 12 Feet
<1
3.7
96
90.5
88.5
85
84.5
11
11
10
13-20
13-19
12-18
107
See Exhibit A-2
Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic
LOCATION
DEPTH
Latitude: 40.575552° Longitude: -105.098391°
GRAPHIC LOG
THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20135030.GPJ TERRACON2012.GDT 9/16/13
Scott Avenue and West Plum Street
Fort Collins, Colorado
SITE:
While drilling
24-hour measurement
WATER LEVEL OBSERVATIONS
PROJECT: Student Housing at Scott Ave.
& W. Plum St.
Page 1 of 1
Advancement Method:
4-inch solid stem flight auger
Abandonment Method:
Borings backfilled with soil cuttings and sand upon
completion.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
Notes:
Project No.: 20135030
Drill Rig: CME-55
Boring Started: 9/3/2013
BORING LOG NO. 4
CLIENT: Taylor Fitzpatrick Capital, Inc.
Scottsdale, Arizona
Driller: Drilling Engineers, Inc.
Boring Completed: 9/3/2013
Exhibit: A-7
0.6
3.0
5.0
VEGETATIVE LAYER, 7 inches
SILTY CLAYEY SAND WITH GRAVEL, brown, very
stiff
SILTY CLAYEY SAND WITH GRAVEL, trace
cobbles, red
Boring Terminated at 5 Feet
101
98.5
96.5
See Exhibit A-2
Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic
LOCATION
DEPTH
Latitude: 40.576149° Longitude: -105.09811°
GRAPHIC LOG
THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20135030.GPJ TERRACON2012.GDT 9/16/13
Scott Avenue and West Plum Street
Fort Collins, Colorado
SITE:
No free water observed
WATER LEVEL OBSERVATIONS
PROJECT: Student Housing at Scott Ave.
& W. Plum St.
Page 1 of 1
Advancement Method:
4-inch solid stem flight auger
Abandonment Method:
Slotted PVC pipe was inserted into test hole with sand
filling the annulus around the PVC pipe.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
Notes:
Project No.: 20135030
Drill Rig: CME-55
Boring Started: 9/3/2013
BORING LOG NO. H-1
CLIENT: Taylor Fitzpatrick Capital, Inc.
Scottsdale, Arizona
Driller: Drilling Engineers, Inc.
Boring Completed: 9/3/2013
Exhibit: A-8
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.
SULFATES (ppm)
SWELL (%)
ELEVATION (Ft.)
PERCENT FINES
WATER
CONTENT (%)
FIELD TEST
RESULTS
SAMPLE TYPE
WATER LEVEL
0.5
5.0
VEGETATIVE LAYER, 6 inches
LEAN CLAY, trace gravel, brown
Boring Terminated at 5 Feet
96
91.5
See Exhibit A-2
Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic
LOCATION
DEPTH
Latitude: 40.575551° Longitude: -105.09836°
GRAPHIC LOG
THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 20135030.GPJ TERRACON2012.GDT 9/16/13
Scott Avenue and West Plum Street
Fort Collins, Colorado
SITE:
No free water observed
WATER LEVEL OBSERVATIONS
PROJECT: Student Housing at Scott Ave.
& W. Plum St.
Page 1 of 1
Advancement Method:
4-inch solid stem flight auger
Abandonment Method:
Slotted PVC pipe was inserted into test hole with sand
filling the annulus around the PVC pipe.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
Notes:
Project No.: 20135030
Drill Rig: CME-55
Boring Started: 9/3/2013
BORING LOG NO. H-2
CLIENT: Taylor Fitzpatrick Capital, Inc.
Scottsdale, Arizona
Driller: Drilling Engineers, Inc.
Boring Completed: 9/3/2013
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.
SULFATES (ppm)
SWELL (%)
ELEVATION (Ft.)
PERCENT FINES
WATER
CONTENT (%)
FIELD TEST
RESULTS
SAMPLE TYPE
WATER LEVEL
OBSERVATIONS
Surface Elev.: 96.5 (Ft.)
DEPTH (Ft.)
5
DRY UNIT
APPENDIX B
LABORATORY TESTING
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Ŷ Fort Collins, Colorado
September 18, 2013 Ŷ Terracon Project No. 20135030
Responsive Ŷ Resourceful Ŷ 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.
Water content Plasticity index
Grain-size distribution
Consolidation/swell
Dry density
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
PL PI
4.0
19.0
4.0
Boring ID Depth Description
WELL-GRADED SAND with SILT and GRAVEL
LEAN CLAY
SILTY, CLAYEY SAND with GRAVEL
SW-SM
CL
SC-SM
Fines
P
L
A
S
T
I
C
I
T
Y
I
N
D
E
X
LIQUID LIMIT
"U" Line
"A" Line
21
35
22
18
14
16
3
21
6
12
89
13
LL USCS
1
2
3
ATTERBERG LIMITS RESULTS
ASTM D4318
1901 Sharp Point Drive, Suite C
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
6 16
20 30
40 50
1.5 6 200
810
11.7
12.6
20.7
31.7
14
LL PL PI
%Silt %Clay
1 4
3/4 1/2
60
fine
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS HYDROMETER
18
16
3
6
1.54
D100
Cc Cu
SILT OR CLAY
4
D30 D10 %Gravel %Sand
1
3
WELL-GRADED SAND with SILT and GRAVEL(SW-SM)
SILTY, CLAYEY SAND with GRAVEL(SC-SM)
21
22
0.453
0.511
2.159
2.767
19
-3
-2
-1
0
1
2
3
100 1,000 10,000
AXIAL STRAIN, %
PRESSURE, psf
SWELL CONSOLIDATION TEST
ASTM D4546
NOTES: Sample exhibited 0.04 percent compression upon wetting under an applied pressure of
1,000 psf.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
PROJECT NUMBER: 20135030
PROJECT: Student Housing at Scott Ave. &
W. Plum St.
SITE: Scott Avenue and West Plum Street
Fort Collins, Colorado
CLIENT: Taylor Fitzpatrick Capital, Inc.
Scottsdale, Arizona
EXHIBIT: B-4
Specimen Identification
9.0 ft
Classification , pcf
2 110 16
WC, %
WELL-GRADED SAND with SILT and GRAVEL(SW-SM)
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. CONSOL_STRAIN-USCS 20135030.GPJ TERRACON2012.GDT 9/16/13
-3
-2
-1
0
1
2
3
100 1,000 10,000
AXIAL STRAIN, %
PRESSURE, psf
SWELL CONSOLIDATION TEST
ASTM D4546
NOTES: Sample exhibited 3.7 percent swell when wetted under an applied pressure of 200 psf.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
PROJECT NUMBER: 20135030
PROJECT: Student Housing at Scott Ave. &
W. Plum St.
SITE: Scott Avenue and West Plum Street
Fort Collins, Colorado
CLIENT: Taylor Fitzpatrick Capital, Inc.
Scottsdale, Arizona
EXHIBIT: B-5
Specimen Identification
2.0 ft
Classification , pcf
4 107 11
WC, %
LEAN CLAY (CL)
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. CONSOL_STRAIN-USCS 20135030.GPJ TERRACON2012.GDT 9/16/13
Geotechnical Engineering Report
Student Housing at Scott Ave. and W. Plum St. Fort Collins, Colorado
September 10, 2013 Terracon Project No. 20135030
gallons gallons
7:00:00 AM 0 0.00 7:00:00 AM 0 0.00
7:30:00 AM 8.05 0.97 7:30:00 AM 0.92 0.11
8:00:00 AM 15.28 2.80 8:00:00 AM 1.24 0.26
8:30:00 AM 13.25 4.39 8:30:00 AM 1.14 0.40
9:00:00 AM 13.75 6.04 9:00:00 AM 0.84 0.50
9:30:00 AM 12.93 7.59 9:30:00 AM 1.48 0.67
10:00:00 AM 12 9.03 10:00:00 AM 1.19 0.82
10:30:00 AM 16.1 10.97 10:30:00 AM 1.1 0.95
11:00:00 AM 14.43 12.70 11:00:00 AM 1.08 1.08
11:30:00 AM 15.58 14.57 11:30:00 AM 1.72 1.29
12:00:00 PM 14.22 16.28 12:00:00 PM 0.99 1.40
12:30:00 PM 14.46 18.01 12:30:00 PM 1.34 1.57
1:00:00 PM 13.85 19.68 1:00:00 PM 1.17 1.71
1:30:00 PM 13.41 21.29 1:30:00 PM 1.43 1.88
2:00:00 PM 15.21 23.11 2:00:00 PM 1.14 2.01
2:30:00 PM 14.86 24.90 2:30:00 PM 1.29 2.17
2:45:00 PM 7.03 25.74 2:45:00 PM 0.72 2.26
kavg = 19.00 ft/day kavg = 4.96 ft/day
6.70E-03 cm/sec 1.75E-03 cm/sec
h= 4.80 feet h= 2.31 feet
d= 4.25 inches d= 4.25 inches
r= 0.18 feet r= 0.18 feet
Tu= 12.60 feet Tu= 6.90 feet
Q= 0.524 ft3/min Q= 0.046 ft3/min
T 23.59 T 23.59
20 20.50 20 20.50
T = 70 oF T = 70 oF
k= 0.0132 feet/min k= 0.0034 feet/min
19.00 feet/day 4.96 feet/day
h = hydraulic head in test hole (ft)
d = diameter of test hole (ft)
r = radius of test hole (ft)
Tu = depth of unsaturated strata (ft)
Q =
T = viscocity of water at temperature T
20 = viscocity of water at 68oF
T= temperature of water used (oF)
k = hydraulic conductivity feet/min
h< Tu < 3h
Cumulative Water
75.26
91.36
105.79
192.52
11.7
(lbs)
0
0.92
2.16
3.3
4.14
5.62
6.81
7.91
Field Hydraulic Conductivity Test Results
Student Housing at Scott Ave. and W. Plum St., Fort Collins, Colorado
APPENDIX C
SUPPORTING DOCUMENTS
Exhibit: C-1
Unconfined
Compressive
Strength
Qu, (tsf)
0.25 to 0.50
1.00 to 2.00
> 4.00
less than 0.25
0.50 to 1.00
2.00 to 4.00
Non-plastic
Low
Medium
High
DESCRIPTION OF SYMBOLS AND ABBREVIATIONS
Hand Penetrometer
Torvane
Dynamic Cone Penetrometer
Photo-Ionization Detector
Organic Vapor Analyzer
SAMPLING
WATER LEVEL
FIELD TESTS
(HP)
(T)
(DCP)
(PID)
(OVA)
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
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
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.
Unconfined
Compression
To obtain the approximate compressive strength of soils
that 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.
Trace
With
Modifier
RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY
Trace
With
Modifier
DESCRIPTIVE SOIL CLASSIFICATION
Boulders
Cobbles
Gravel
Sand
Silt or Clay
Descriptive Term(s)
of other constituents
< 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.
STRENGTH TERMS
BEDROCK
Loose
Medium Dense
Dense
0 - 3
4 - 9
10 - 29
30 - 50
7 - 18
19 - 58
Very Soft
Soft
Medium-Stiff
Stiff
Very Stiff
Standard
Penetration or
N-Value
Blows/Ft.
2 - 4
4 - 8
8 - 15
< 3
5 - 9
19 - 42
> 42
30 - 49
50 - 89
20 - 29
Medium Hard
Very Dense
RELATIVE DENSITY OF COARSE-GRAINED
SOILS
Descriptive
Term
(Density)
Very Loose
> 50
Ring
Sampler
Blows/Ft.
0 - 6
59 - 98
> 99
Descriptive
Term
(Consistency)
Hard
0 - 1
Ring
Sampler
Blows/Ft.
3 - 4
10 - 18
Ring
Sampler
Blows/Ft.
< 30
90 - 119
Standard
Penetration or
N-Value
Blows/Ft.
Descriptive
Term
(Consistency)
Weathered
Firm
Very Hard
CONSISTENCY OF FINE-GRAINED SOILS
(More than 50% retained on No. 200 sieve.)
Density determined by
Standard Penetration Resistance
(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.
_ 15 - 30
> 30
> 119
< 20
30 - 49
50 - 79
>79
Hard
Terracon Project No. 20135030
Hydraulic Conductivity Test #1 (H-1) Hydraulic Conductivity Test #2 (H-2)
Time Water
Added (lbs)
Cumulative Water Time
Water
Added (lbs)
saturated flow rate of water to
maintain a constant head in test hole
(ft3/min)
(lbs)
0
8.05
23.33
36.58
50.33
63.26
207.38
214.41
Parameters for DP - 1
121.37
135.59
150.05
163.9
177.31
8.99
10.71
Parameters for DP - 1
13.04
14.21
15.64
16.78
18.07
18.79
k = ( ( ) )
h
SLOTTED PVC
PIPE
FILTER
SAND
GROUND
SURFACE
d
Tu
WATER TABLE OR
IMPERVIOUS LAYER
Exhibit B-6
25
1
3
4.0 35.11
4.0
GRAIN SIZE IN MILLIMETERS
PERCENT FINER BY WEIGHT
coarse fine
3/8 3 100
3 2 140
COBBLES
GRAVEL SAND
USCS Classification
67.6
55.7
D60
coarse medium
4.0
4.0
Boring ID Depth
Boring ID Depth
GRAIN SIZE DISTRIBUTION
ASTM D422
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
PROJECT NUMBER: 20135030
PROJECT: Student Housing at Scott Ave. &
W. Plum St.
SITE: Scott Avenue and West Plum Street
Fort Collins, Colorado
CLIENT: Taylor Fitzpatrick Capital, Inc.
Scottsdale, Arizona
EXHIBIT: B-3
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS-2 20135030.GPJ TERRACON2012.GDT 9/16/13
Fort Collins, Colorado
PROJECT NUMBER: 20135030
PROJECT: Student Housing at Scott Ave. &
W. Plum St.
SITE: Scott Avenue and West Plum Street
Fort Collins, Colorado
CLIENT: Taylor Fitzpatrick Capital, Inc.
Scottsdale, Arizona
EXHIBIT: B-2
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. ATTERBERG LIMITS 20135030.GPJ TERRACON2012.GDT 9/16/13
CL-ML
WEIGHT (pcf)
ATTERBERG
LIMITS
LL-PL-PI
OBSERVATIONS
Surface Elev.: 101.5 (Ft.)
DEPTH (Ft.)
5
DRY UNIT
WEIGHT (pcf)
ATTERBERG
LIMITS
LL-PL-PI
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.
SULFATES (ppm)
SWELL (%)
ELEVATION (Ft.)
PERCENT FINES
WATER
CONTENT (%)
FIELD TEST
RESULTS
SAMPLE TYPE
WATER LEVEL
OBSERVATIONS
Surface Elev.: 96.4 (Ft.)
DEPTH (Ft.)
5
10
DRY UNIT
WEIGHT (pcf)
ATTERBERG
LIMITS
LL-PL-PI
See Appendix B for description of laboratory
procedures and additional data (if any).
See Appendix C for explanation of symbols and
abbreviations.
SULFATES (ppm)
SWELL (%)
ELEVATION (Ft.)
PERCENT FINES
WATER
CONTENT (%)
FIELD TEST
RESULTS
SAMPLE TYPE
WATER LEVEL
OBSERVATIONS
Surface Elev.: 101.5 (Ft.)
DEPTH (Ft.)
5
10
DRY UNIT
WEIGHT (pcf)
ATTERBERG
LIMITS
LL-PL-PI
Borings backfilled with soil cuttings and sand upon
completion.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
Notes:
Project No.: 20135030
Drill Rig: CME-55
Boring Started: 9/3/2013
BORING LOG NO. 2
CLIENT: Taylor Fitzpatrick Capital, Inc.
Scottsdale, Arizona
Driller: Drilling Engineers, Inc.
Boring Completed: 9/3/2013
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
abbreviations.
SULFATES (ppm)
SWELL (%)
ELEVATION (Ft.)
PERCENT FINES
WATER
CONTENT (%)
FIELD TEST
RESULTS
SAMPLE TYPE
WATER LEVEL
OBSERVATIONS
Surface Elev.: 102.1 (Ft.)
DEPTH (Ft.)
5
10
15
20
25
DRY UNIT
WEIGHT (pcf)
ATTERBERG
LIMITS
LL-PL-PI
Abandonment Method:
Borings backfilled with soil cuttings and sand upon
completion.
1901 Sharp Point Drive, Suite C
Fort Collins, Colorado
Notes:
Project No.: 20135030
Drill Rig: CME-55
Boring Started: 9/3/2013
BORING LOG NO. 1
CLIENT: Taylor Fitzpatrick Capital, Inc.
Scottsdale, Arizona
Driller: Drilling Engineers, Inc.
Boring Completed: 9/3/2013
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.
SULFATES (ppm)
SWELL (%)
ELEVATION (Ft.)
PERCENT FINES
WATER
CONTENT (%)
FIELD TEST
RESULTS
SAMPLE TYPE
WATER LEVEL
OBSERVATIONS
Surface Elev.: 101.2 (Ft.)
DEPTH (Ft.)
5
10
15
20
25
DRY UNIT
WEIGHT (pcf)
ATTERBERG
LIMITS
LL-PL-PI