HomeMy WebLinkAboutSCHRADER PROPANE OFFICE & MINOR VEHICLE REPAIR - PDP - PDP170015 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTGEOTECHNICAL SUBSURFACE EXPLORATION REPORT
PROPOSED SCHRADER PROPANE OFFICES
LOTS 15 & 16, BLOCK 3, EVERGREEN PARK REPLAT
FORT COLLINS, COLORADO
SOILOGIC # 16-1158
JULY 18, 2016
Soilogic, Inc.
3050 67th Avenue, Suite 200 Greeley, CO 80634 (970) 535-6144
P.O. Box 1121 Hayden, CO 81639 (970) 276-2087
July 18, 2016
WG Architects
P.O. Box 270788
Fort Collins, Colorado 80527
Attn: Mr. Don Shields
Re: Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
Lots 15 & 16, Block 3, Evergreen Park Replat
Fort Collins, Colorado
Soilogic # 16-1158
Mr. Shields:
Soilogic, Inc. (Soilogic) personnel have completed the geotechnical subsurface
exploration you requested for the proposed Schrader Propane office building to be
constructed on Lots 15 & 16, Block 3 of the Evergreen Park Replat industrial
development in Fort Collins, Colorado. The results of our subsurface exploration and
pertinent geotechnical engineering recommendations are included with this report.
In general, the subsurface materials encountered in the completed site borings consisted
of a thin mantle of vegetation and topsoil underlain by rust/brown lean clay with sand.
The lean clay was very stiff in terms of consistency, exhibited no to moderate swell
potential at in-situ moisture and density conditions and extended to depths ranging from
approximately 3½ to 4½ feet below ground surface, where it transitioned to rust/brown
silty sand and gravel and cleaner sand and gravel with depth. The silty sand and gravel
was medium dense in terms of relative density, would be expected to be non-expansive or
possess low swell potential based on the material’s physical properties and engineering
characteristics and extended to the bottom of all borings at depths ranging from
approximately 10 to 15 feet below present site grade. Groundwater was encountered in
the completed site borings at depths ranging from approximately 7 to 8 feet below ground
surface when checked immediately after the completion of drilling. When checked
approximately 24 hours after completion of drilling, groundwater was measured in
borings B-2 and B-4 at depths of approximately 7½ and 7 feet below ground surface
Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
Lots 15 & 16, Block 3, Evergreen Park Replat
Fort Collins, Colorado
Soilogic # 16-1158
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respectively. Dry cave-ins were measured in borings B-1 and B-3 at depths of
approximately 7½ and 6½ feet below grade respectively at that time.
Based on the subsurface conditions encountered in the completed site borings, results of
laboratory testing and type of construction proposed, it is our opinion the proposed office
building could be constructed with conventional spread footing foundations and floor
slabs bearing on a mat of properly moisture-conditioned and compacted
overexcavation/backfill consisting of on-site overburden lean clay or similar soils.
Extending footing foundations to bear on low-swelling silty sand and gravel at greater
depth could also be considered, precluding the need for overexcavation/backfill beneath
footing foundations. However, overexcavation/backfill procedures beneath the building
floor slab would still be required. The overexcavation/backfill procedures will help
develop LVC-potential foundation bearing and floor slab support across the building
footprint and reduce the potential for total and differential movement of those supported
elements subsequent to construction. The risk of some movement cannot be eliminated.
Similar methods should be used in order to develop LVC-potential pavement and exterior
flatwork subgrades. Overexcavation/backfill beneath gravel-surfaced pavements would
not be required. Other opinions and recommendations concerning design criteria and
construction details for the proposed site improvements are included with this report.
Recommendations concerning design and construction of a site retaining wall and
pavement section design options are also included.
Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
Lots 15 & 16, Block 3, Evergreen Park Replat
Fort Collins, Colorado
Soilogic # 16-1158
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We appreciate the opportunity to be of service to you on this project. If you have any
questions concerning the enclosed information or if we can provide any further
assistance, please do not hesitate to contact us.
Very Truly Yours,
Soilogic, Inc. Reviewed by:
Wolf von Carlowitz, P.E. Darrel DiCarlo, P.E.
Principal Engineer Senior Project Engineer
36746 44271
GEOTECHNICAL SUBSURFACE EXPLORATION REPORT
PROPOSED SCHRADER PROPANE OFFICES
LOTS 15 & 16, BLOCK 3, EVERGREEN PARK REPLAT
FORT COLLINS, COLORADO
SOILOGIC # 16-1158
July 18, 2016
INTRODUCTION
This report contains the results of the completed geotechnical subsurface exploration for
the proposed Schrader Propane office building to be constructed on Lots 15 & 16, Block
3 of the Evergreen Park Replat industrial development in Fort Collins, Colorado. The
purpose of our exploration was to describe the subsurface conditions encountered in the
completed site borings and develop the test data necessary to provide recommendations
concerning design and construction of the proposed building foundations and support of
floor slabs, exterior flatwork and site pavements. The conclusions and recommendations
outlined in this report are based on the results of the completed field and laboratory
testing and our experience with subsurface conditions in this area.
PROPOSED CONSTRUCTION
Based on the provided site plan, we understand the proposed office building will have a
plan area of approximately 5,500 square feet and be a single-story steel structure
constructed as slab-on-grade containing both office and service bay areas. Foundations
loads for the building are anticipated to be relatively light, with maximum continuous
wall loads on the order of 3.5 kips per lineal foot and individual column loads less than
100 kips. Paved drive and parking areas are also anticipated as part of the proposed site
improvements. Small grade changes are anticipated to develop finish site grades in
building and pavement areas.
SITE DESCRIPTION
The development property includes Lots 15 and 16, Block 3 of the Evergreen Park Replat
industrial development in Fort Collins, Colorado. At the time of our site exploration, the
lot was undeveloped, contained a moderate growth of weed and grass vegetation and was
relatively level, with the maximum difference in ground surface elevation across the
Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
Lots 15 & 16, Block 3, Evergreen Park Replat
Fort Collins, Colorado
Soilogic # 16-1158
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property estimated to be less than 2 feet. Evidence of prior building construction was not
observed in the proposed construction areas at the time of our exploration.
SITE EXPLORATION
Field Exploration
To develop subsurface information for the proposed site improvements, a total of four (4)
soil borings were completed. Two (2) borings were advanced in the area of the proposed
office building to a depth of approximately 15 feet below present site grade. Two (2)
additional borings were completed in the site pavement areas to a depth of approximately
10 feet below ground surface. The boring locations were established in the field by
Soilogic, Inc. (Soilogic) personnel based on a provided site plan, using a mechanical
surveyor's wheel and estimating angles from identifiable site references. The boring
locations should be considered accurate only to the degree implied by the methods used
to make the field measurements. A diagram indicating the approximate boring locations
is included with this report. Graphic logs of each of the auger borings are also included.
The test holes were advanced using 4-inch diameter continuous-flight auger, powered by
a truck-mounted CME-45 drill rig. Samples of the subsurface materials were obtained at
regular intervals using California and split-barrel sampling procedures in general
accordance with ASTM specification D-1586. As part of the D-1586 sampling
procedure, standard sampling barrel are driven into the substrata using a 140-pound
hammer falling a distance of 30 inches. The number of blows required to advance the
sampler a distance of 12 inches is recorded and helpful in estimating the consistency or
relative density of the soils encountered. In the California barrel sampling procedure,
lesser disturbed samples are obtained in removable brass liners. Samples of the
subsurface materials obtained in the field were sealed and returned to the laboratory for
further evaluation, classification and testing.
Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
Lots 15 & 16, Block 3, Evergreen Park Replat
Fort Collins, Colorado
Soilogic # 16-1158
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Laboratory Testing
The samples collected were tested in the laboratory to measure natural moisture content
and visually or manually classified in accordance with the Unified Soil Classification
System (USCS). The USCS group symbols are indicated on the attached boring logs.
An outline of the USCS classification system is included with this report.
As part of the laboratory testing, a calibrated hand penetrometer (CHP) was used to
estimate the unconfined compressive strength of essentially cohesive specimens. The
CHP also provides a more reliable estimate of soil consistency than tactual observation
alone. Dry density, Atterberg limits, -200 wash and swell/consolidation tests were
completed on selected samples to help establish specific soil characteristics. Atterberg
limits tests are used to determine soil plasticity. The percent passing the #200 size sieve
(-200 wash test) is used to determine the percentage of fine grained materials (clay and
silt) in a sample. Swell/consolidation tests are performed to evaluate soil volume change
potential with variation in moisture content. The results of the completed laboratory tests
are outlined on the attached boring logs and swell/consolidation test summaries. Water
Soluble Sulfates (WSS) tests were also completed on two (2) selected soil samples to
evaluate corrosive soil characteristics with respect to buried concrete and results
discussed subsequently in this report.
SUBSURFACE CONDITIONS
In general, the subsurface materials encountered in the completed site borings consisted
of a thin mantle of vegetation and topsoil underlain by rust/brown lean clay with sand.
The lean clay was very stiff in terms of consistency, exhibited no to moderate swell
potential at in-situ moisture and density conditions and extended to depths ranging from
approximately 3½ to 4½ feet below ground surface, where it was underlain by rust/brown
silty sand and gravel and cleaner sand and gravel with depth. The sand and gravel was
medium dense in terms of relative density, would be expected to be non-expansive or
possess low swell potential based on the material’s physical properties and engineering
characteristics and extended to the bottom of all borings at depths ranging from
approximately 10 to 15 feet below present site grade.
Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
Lots 15 & 16, Block 3, Evergreen Park Replat
Fort Collins, Colorado
Soilogic # 16-1158
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The stratigraphy indicated on the included boring logs represents the approximate
location of changes in soil types. Actual changes may be more gradual than those
indicated.
Groundwater was encountered in the completed site borings at depths ranging from
approximately 7 to 8 feet below ground surface when checked immediately after the
completion of drilling. When checked approximately 24 hours after completion of
drilling, groundwater was measured in borings B-2 and B-4 at depths of approximately
7½ and 7 feet below ground surface respectively. Dry cave-ins were measured in borings
B-1 and B-3 at depths of approximately 7½ and 6½ feet below grade at that time.
Groundwater levels will vary seasonally and over time based on weather conditions, site
development, irrigation practices and other hydrologic conditions. Perched and/or
trapped groundwater conditions may also be encountered at times throughout the year.
Perched water is commonly encountered in soils overlying less permeable soil layers
and/or bedrock. Trapped water is typically encountered within more permeable zones of
layered soil and bedrock systems. The location and amount of perched/trapped water can
also vary over time.
ANALYSIS AND RECOMMENDATIONS
General
The near-surface lean clay soils encountered at this site exhibited no to moderate swell
potential at in-situ moisture and density conditions. Total and differential heaving of site
improvements placed directly on or immediately above the expansive clay soils would be
expected as the moisture content of those materials increases subsequent to construction.
Based on the subsurface conditions encountered and results of laboratory testing, it is our
opinion overexcavation/backfill procedures could be completed beneath the building
footing foundations and floor slabs to reduce the potential for movement of those
supported elements subsequent to construction. The risk of some movement cannot be
eliminated. Extending footing foundations through expansive near-surface clay to bear
Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
Lots 15 & 16, Block 3, Evergreen Park Replat
Fort Collins, Colorado
Soilogic # 16-1158
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on low-swelling silty sand and gravel, anticipated to be encountered at depths ranging
from approximately 3½ to 4½ feet below grade, could also be considered as an
alternative to overexcavation/backfill procedures. If extending footing foundations to
bear at greater depth will be completed, overexcavation/backfill procedures beneath the
building floor slab would still be required. Recommendations concerning
overexcavation/backfill procedures to redevelop foundation and floor slab support for the
building are outlined below. If some structural and floor slab movement and associated
distress cannot be tolerated, a drilled pier and structural floor system should be employed.
Drilled pier foundations and structural floor systems would offer the most effective
system for mitigating the potential for total and differential movement of the building and
building floor slab subsequent to construction in the expansive soils environment.
Drilled piers would anchor the building into site bedrock, significantly reducing the
potential for movement of the structure. If drilled pier foundations are to be used,
structural flooring systems or overexcavation/backfill procedures to develop low volume
change (LVC) floor slab subgrades would be required. Recommendations concerning the
design and construction of drilled pier foundations can be provided at your request.
Building and Pavement/Exterior Flatwork Subgrade Development
To develop low-volume-change (LVC) potential foundation and floor slab support, and
reduce the potential for total and differential movement of the building and building floor
slab subsequent to construction, we recommend a zone of reconditioned soil be
developed beneath those supported elements. The reconditioned mat will provide a zone
of material immediately beneath the building foundations and floor slabs which will have
low potential for volume change subsequent to construction. The LVC mat and
surcharge loads placed on the underlying soils by the reconditioned mat would reduce the
potential for total and differential movement of the supported improvements subsequent
to construction. The reconditioned zone would also assist in distributing movement in
the event that some swelling of the materials underlying the reconditioned zone occurs.
The overexcavation zone should extend to low-swelling silty sand and gravel, anticipated
to be encountered at depths ranging from approximately 3½ to 4½ feet below grade. The
Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
Lots 15 & 16, Block 3, Evergreen Park Replat
Fort Collins, Colorado
Soilogic # 16-1158
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overexcavation area should extend a minimum of 8 inches laterally past the exterior
perimeter of the building footing foundations for every 12 inches of overexcavation
depth.
Since movement of site pavements and exterior flatwork is generally less consequential
than structural and floor slab movement, it is our opinion the overexcavation zone
beneath site pavements and exterior flatwork could be reduced to a minimum of 18
inches below finish subgrade level. The 18-inch thick zone can be developed through
any combination of overexcavation/backfill and fill placement procedures.
Overexcavation/backfill procedures would not be required beneath gravel-surfaced
pavements.
Soils used as overexcavation/backfill should consist of approved materials free from
organic matter, debris and other objectionable materials. Based on results of the
completed laboratory testing, it is our opinion the site lean clay could be used as
overexcavation/backfill provided care is taken to develop the proper moisture content in
those materials at the time of placement and compaction. Essentially-granular imported
structural fill materials could also be used as overexcavation/backfill in the building area
where complete removal of the expansive near surface lean clay will be completed.
Essentially granular structural fill soils should not be used in pavement and exterior
flatwork where partial removal of the expansive lean clay soils will be completed due to
the ability of those materials to pond and transmit water.
All existing topsoil and vegetation should be removed from the building, pavement and
exterior flatwork areas. After stripping and completing all cuts and overexcavation
procedures and prior to placement of any new fill, overexcavation/backfill or gravel
surfacing, we recommend the exposed subgrades be scarified to a depth of 9 inches,
adjusted in moisture content and compacted to at least 95% of the materials standard
Proctor maximum dry density. The moisture content of the scarified soils should be
adjusted to be within the range of -1 to +3% of standard Proctor optimum moisture
content for the site lean clay and ±2% of standard Proctor optimum moisture content for
essentially granular sand and gravel at the time of compaction. Fill and
overexcavation/backfill materials consisting of the site lean clay or imported structural
Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
Lots 15 & 16, Block 3, Evergreen Park Replat
Fort Collins, Colorado
Soilogic # 16-1158
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fill should be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture
content and compacted as outlined for the scarified soils above. At the high end of the
above recommended moisture content range, some pumping of the lean clay
overexcavation/backfill soils may be observed and would be expected.
Care should be taken to maintain the proper moisture content in the bearing/subgrade
soils prior to foundation and floor slab concrete placement and/or paving. The prepared
structural mat should not be left exposed for extended periods of time. In the event that
the reconditioned soils are allowed to dry out or if rain, snowmelt or water from any
source is allowed to infiltrate the bearing/subgrade soils, reworking of those materials or
removal/replacement procedures may be required.
Inherent risks exist when building in areas of expansive soils. The overexcavation/
backfill procedures outlined above will reduce but not eliminate the potential for
movement of the building, building floor slab, site pavements and exterior flatwork
subsequent to construction. Some movement of lightly-loaded site pavements and
exterior flatwork should be expected.
Footing Foundations
For design of footing foundations bearing on suitable overexcavation/backfill soils placed
and compacted as outlined above or natural undisturbed silty sand and gravel if extending
footing foundations to bear at greater depth will be completed, we recommend using a
maximum net allowable soil bearing pressure of 1,500 psf. As a precaution, we
recommend the footing foundations be designed to maintain a minimum dead-load
pressure of 500 psf on the supporting soils. A minimum dead load pressure would not be
required for footing foundations extended to bear on low-swelling silty sand and gravel.
Exterior footings should bear a minimum of 30 inches below finished adjacent exterior
grade to provide frost protection. We recommend formed strip footings have a minimum
width of 12 inches and isolated pad foundations have a minimum width of 24 inches in
order to facilitate construction and reduce the potential for development of eccentrically
loaded footings. Actual footing widths should be designed by a structural engineer.
Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
Lots 15 & 16, Block 3, Evergreen Park Replat
Fort Collins, Colorado
Soilogic # 16-1158
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For design of footing foundations and foundation walls to resist lateral movement, a
passive equivalent fluid pressure value of 250 pcf could be used. The top 30 inches of
subgrade could be considered a surcharge load but should not be used in the passive
resistance calculations. A coefficient of friction of 0.35 could be used between
foundation and floor slab concrete and the bearing/subgrade soils to resist sliding. The
recommended passive equivalent fluid pressure value and coefficient of friction do not
include a factor of safety.
We estimate settlement of footing foundations supported on a suitable mat of properly-
placed and compacted fill and/or overexcavation/backfill or natural undisturbed silty sand
and gravel encountered with depth and resulting from the assumed structural loads would
be less than 1 inch. Differential settlement could approach the amount of total settlement
estimated above. If water from any source is allowed to infiltrate the foundation bearing
soils, additional movement of those supported elements could occur.
Seismicity
Based on the results of our exploration and our review of the International Building Code
(2003), a soil profile type D could be used for the site strata. Based on our review of
United States Geologic Survey (USGS) mapped information, design spectral response
acceleration values of SDS = .219 (21.9%) and S
D1 = .093 (9.3%) could be used.
Floor Slabs
The building floor slab could be supported directly on the overexcavation/backfill
material placed and compacted as outlined above. A modulus of subgrade reaction (k)
value of 150 pci could be used for design of floor slabs supported on overexcavation/
backfill soils consisting of the on-site clay or similar soils. Disturbed subgrades or
subgrade materials that have been allowed to dry out or become wet and softened should
be removed and replaced or reconditioned in place prior to concrete placement.
As a precaution, we recommend all partition walls supported above at-grade floor slabs
be constructed as floating walls to help reduce the potential for slab movement causing
Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
Lots 15 & 16, Block 3, Evergreen Park Replat
Fort Collins, Colorado
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distress in upper sections of the building. A minimum 1½ inch void space is
recommended beneath all partition walls. Special attention to stair systems, door
framing, drywall installation, garage door tracks and trim carpentry should be taken to
isolate those elements from the floor slab, allowing for some movement of the floor slab
to occur without transmitting stresses to the overlying structure.
We do not expect a floor covering will be used in a majority of the shop area of this
building. Depending on the type of floor covering and floor covering adhesive used in
office and other finished areas, a vapor barrier may be required immediately beneath the
facility floor slab in those areas in order to maintain flooring product manufacturer
warranties. A vapor barrier would help reduce the transmission of moisture through the
floor slab. However, the unilateral moisture release caused by placing concrete on an
impermeable surface can increase slab curl. The amount of slab curl can be reduced by
careful selection of an appropriate concrete mix. Slab curl cannot be eliminated. We
recommend the owner, architect and flooring contractor consider the performance of the
slab in conjunction with the proposed flooring products to help determine if a vapor
barrier will be required and where best to position the vapor barrier in relation to the floor
slab. Additional guidance and recommendations concerning slab on grade design can be
found in American Concrete Institute (ACI) section 302.
Pavement and Exterior Flatwork Subgrades
Pavement and exterior flatwork subgrades should be developed as outlined in the
“Building and Pavement/Exterior Flatwork Subgrade Development” section of this
report. Concrete and asphalt pavements and exterior flatwork could be supported directly
on the overexcavation/backfill soils placed and compacted as outlined in that section of
this report. Overexcavation/backfill procedures would not be required beneath gravel-
surfaced pavements, such that gravel surfacing could be supported directly on
reconditioned subgrade soils and/or suitable fill soils also placed and compacted also as
outlined above. Care should be taken to avoid disturbing the reconditioned subgrades
and site fill and overexcavation/backfill soils prior to placement of site pavements and
exterior flatwork. In addition, efforts to maintain the proper moisture content in the
subgrade soils should be made. If subgrade soils are disturbed or allowed to dry out or
Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
Lots 15 & 16, Block 3, Evergreen Park Replat
Fort Collins, Colorado
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become elevated in moisture content, those materials should be reworked in place or
removed and replaced prior to paving and/or concrete placement.
Some movement of site pavements and exterior flatwork should be expected as the
moisture content of the subgrade soils increases subsequent to construction. Deeper
overexcavation/backfill procedures could be considered beneath site pavements and
exterior flatwork to further reduce the potential for post-construction movement of those
supported improvements. Care should be taken to ensure that when site pavements and
exterior flatwork move, positive drainage will be maintained away from the structure.
Pavements
The site lean clay would be subject to low remolded shear strength. A resistance value
(R-value) of 5 was estimated for the site lean clay and used in the pavement section
design. Traffic loading on site pavements is expected to consist of areas of low volumes
of automobiles and light trucks as well as areas of higher light vehicle traffic volumes
and occasional heavier trash, delivery and emergency vehicle traffic. Equivalent 18-kip
single axle loads (ESAL’s) were estimated for the quantity of site traffic anticipated.
Two (2) general design classifications are outlined below in Table I. Standard duty
pavements could be considered in automobile drive and parking areas. Heavy duty
pavements should be considered for access drives and other areas of the site expected to
receive higher traffic volumes or heavier trash, delivery and emergency truck traffic.
Proofrolling of the pavement subgrades should be completed to help identify unstable
areas. Areas which pump or deform excessively (greater than 1 inch) should be mended
prior to asphalt, PCC or aggregate base course placement. Isolated areas of subgrade
instability can be mended on a case-by-case basis. If more extensive areas of subgrade
instability are observed and depending on the in-place moisture content of the subgrade
soils immediately prior to paving, the time of year when construction occurs and other
hydrologic conditions, overall stabilization of the subgrade soils may become necessary
to develop a suitable paving platform. If required, we recommend consideration be given
to stabilization of the pavement subgrades with Class C fly ash. With the increase in
support strength developed by the fly ash stabilization procedures, it is our opinion some
credit for the stabilized zone could be included in the pavement section design, reducing
Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
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Fort Collins, Colorado
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the required thickness of overlying asphaltic concrete and aggregate base course. Fly ash
stabilization can also eliminate some of the uncertainty associated with attempting to
pave during periods of inclement weather. Pavement section design options
incorporating some structural credit for the fly ash-stabilized subgrade soils are outlined
below in Table I.
TABLE I – PAVEMENT SECTION DESIGN
Standard Duty Heavy Duty
Option A – Composite
Asphaltic Concrete (Grading S or SX)
Aggregate Base (Class 5 or 6)
4”
6”
5”
8”
Option B – Composite on Stabilized Subgrade
Asphaltic Concrete (Grading S or SX)
Aggregate Base (Class 5 or 6)
Fly Ash Stabilized Subgrade
3”
4”
12”
4”
6”
12”
Option C - Portland Cement Concrete Pavement
PCCP
5”
6”
Asphaltic concrete should consist of a bituminous plant mix composed of a mixture of
aggregate, filler, binders and additives (if required) meeting the design requirements of
the City of Fort Collins. Aggregate used in the asphaltic concrete should meet specific
gradation requirements such as Colorado Department of Transportation (CDOT) grading
S (¾-inch minus) or SX (½-inch minus) specifications. Hot mix asphalt designed using
“Superpave” criteria should be compacted to within 92 to 96% of the materials Maximum
Theoretical Density. Aggregate base should be consistent with CDOT requirements for
Class 5 or Class 6 aggregate base, placed in loose lifts not to exceed 9 inches thick,
adjusted to within ±2% of standard Proctor optimum moisture content and compacted to
at least 95% of the materials standard Proctor maximum dry density.
If fly ash stabilization procedures will be completed, we recommend the addition of 13%
Class ‘C’ fly ash based on component dry unit weights. A 12-inch thick stabilized zone
should be constructed by thoroughly blending the fly ash with the in-place subgrade soils.
Some “fluffing” of the finish subgrade level should be expected with the stabilization
procedures. The blended materials should be adjusted in moisture content to within the
range of ±2% of standard Proctor optimum moisture content and compacted to at least
Geotechnical Subsurface Exploration Report
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Fort Collins, Colorado
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95% of the material’s standard Proctor maximum dry density within two (2) hours of fly
ash addition.
For areas subjected to truck turning movements and/or concentrated and repetitive
loading such as dumpster or truck parking and loading areas, we recommend
consideration be given to the use of Portland cement concrete pavement with a minimum
thickness of 6 inches. The concrete used for site pavements should be entrained with 4%
to 8% air and have a minimum 28-day compressive strength of 4,200 psi and maximum
water cement ratio of 0.44. Woven wire mesh or fiber entrained concrete should be
considered to help in the control of shrinkage cracking.
The proposed pavement section designs do not include an allowance for excessive
loading conditions imposed by heavy construction vehicles or equipment. Heavily
loaded concrete or other building material trucks and construction equipment can cause
some localized distress to site pavements. The recommended pavement sections are
minimums and periodic maintenance efforts should be expected. A preventative
maintenance program can help increase the service life of site pavements.
Gravel Surfaced Pavements
The subgrade soils for all-weather surfaced areas should be developed as outlined in the
“Building and Pavement/Exterior Flatwork Subgrade Development” section of this
report. Gravel surfacing could be supported directly on the reconditioned subgrade soils
and/or suitable fill soils placed and compacted as outlined in that section. Care will be
required at the time of construction to ensure stable subgrade soils are developed
immediately prior to surfacing.
The load-carrying capacity of the all-weather surfacing would be most dependent on
subgrade strength. The lean clay subgrade soils would be subject to strength loss when
elevated in moisture content such that care should be taken to develop adequate drainage
across the surface of the gravel-surfaced areas and away from the edges of the gravel
pavement. Water which is allowed to pond on or adjacent to the gravel-surfaced areas
Geotechnical Subsurface Exploration Report
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Fort Collins, Colorado
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can result in a loss of subgrade support and unsatisfactory performance of the aggregate
surfacing over time.
Materials used to develop all-weather/gravel surfaced areas should consist of select
granular materials meeting CDOT Class 5 or 6 sieve analysis specifications. Aggregate
base course, recycled asphalt pavement (RAP) or recycled concrete materials could be
considered for use. We recommend a minimum of four (4) inches of granular surfacing
be developed for the all-weather pavement areas of the site. Thicker gravel sections may
be appropriate for areas expected to service greater traffic volumes and/or heavy truck
traffic. Aggregate surfacing should be placed in loose lifts not to exceed 9 inches thick,
adjusted to within ±2% of standard Proctor optimum moisture content and compacted to
at least 95% of the material’s standard Proctor maximum dry density. With the intrinsic
qualities of gravel-surfaced drive/parking areas, periodic maintenance efforts should be
expected.
Site Retaining Wall
A concrete retaining wall is anticipated in the southeast corner of the subject property
where a storm water detention area is anticipated. As a precaution, we recommend the
retaining wall footing foundation in this area be extended to bear on low-swelling silty
sand and gravel. Overexcavation/backfill procedures as outlined above could also be
considered in this area to develop low volume change potential retaining wall foundation
support. The retaining wall footing foundation should bear a minimum of 30 inches
below grade at the front of the wall to provide frost protection. For design of retaining
wall footing foundations bearing on natural, undisturbed silty sand and gravel or properly
placed and compacted overexcavation/backfill developed as outlined above, we
recommend using a maximum net allowable soil bearing pressure of 1,500 psf. We
estimate settlement of the retaining wall footing foundation resulting from the assumed
structural loads would be less than 1 inch. Differential settlement along the length of the
wall could approach the amount of total settlement estimated above.
Care should be taken to prevent the development of unbalanced hydrostatic loads on the
retaining wall. A drainage blanket consisting of 12 inches of free-draining rock placed
Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
Lots 15 & 16, Block 3, Evergreen Park Replat
Fort Collins, Colorado
Soilogic # 16-1158
14
behind the wall and extending the full height of the wall from approximate grade at the
front of the wall to approximately 12 to 18 inches below finish grade on the retained soil
side of the wall should be constructed. We recommend ¾-inch or larger washed rock be
used to construct the drainage blanket. The top 12 to 18 inches of retaining wall backfill
should consist of an essentially cohesive soil to reduce the potential for immediate
surface water infiltration into the wall backfill. A filter fabric should be employed
between all free-draining aggregate and adjacent soil interfaces to reduce the potential for
the migration of finer-grained soils into the gap-graded rock.
Weep holes or other approved methods should be employed to help transfer any collected
water to the front of the wall. A water collection system, similar to a perimeter drain
system could also be considered. A typical collection drain system would consist of 4-
inch diameter rigid perforated pipe surrounded by a minimum of 6 inches of the free-
draining aggregate and placed at the base of the retained soils side of the wall. The invert
of the drain pipe at the high point of the system should be placed at approximate front-of-
wall grade and sloped a minimum of ⅛-inch per foot to facilitate efficient water removal
to an appropriate outfall. Flap gates or other approved methods should be employed at all
free outfalls to reduce the potential for animal access and reverse flow in the system.
Retaining wall backfill should consist of approved low-volume-change (LVC) and
essentially granular materials free from organic matter and debris. Essentially-granular
soils offer better stacking characteristics and are less prone to movements associated with
freezing through the face of the walls than finer-grained materials. Materials consistent
with Colorado Department of Transportation (CDOT) Class 7 aggregate base course or
Class I structure backfill could be used as retaining wall backfill. Retaining wall backfill
should be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture content
and compacted to at least 95% of the materials standard Proctor maximum dry density.
The moisture content of the backfill soils should be adjusted to within ±2% of standard
Proctor optimum moisture content at the time of compaction.
Excessive lateral stresses can be imposed on retaining walls during backfilling when
using heavier mechanical compaction equipment. We recommend compaction of
Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
Lots 15 & 16, Block 3, Evergreen Park Replat
Fort Collins, Colorado
Soilogic # 16-1158
15
retaining wall backfill be completed using light mechanical or hand compaction
equipment.
For design of retaining walls protected from hydrostatic loading and backfilled with
select granular fill, we recommend using an angle of internal friction of Φ=30° and active
equivalent fluid pressure value of 40 pounds per cubic foot in addition to any surcharge
loads. The equivalent fluid pressure value outlined above is based on an active stress
distribution analysis in which some rotation of the retaining wall is assumed. The angle
of internal friction and equivalent fluid pressure values outlined above do not include a
factor of safety. Sloped backfill geometry, surcharge loads on the retained soil side of the
walls or point loads developed in the wall backfill can add to the lateral forces on
retaining walls. If parking areas are anticipated at the top of site retaining walls, we
recommend the walls be designed to include surcharge loads from parked vehicles in
these areas.
The lateral driving forces on the walls will be resisted through a combination of the
sliding friction of the footing foundations and passive earth pressure against the
embedded portion of the wall below frost depth. A passive equivalent fluid pressure
value of 275 pcf could be used for that portion of the wall extended below frost depth,
considered to be 30 inches in this area. A coefficient of friction of 0.45 could be used
between foundation concrete and the bearing soils to resist sliding. The recommended
passive equivalent fluid pressure value and coefficient of friction do not include a factor
of safety.
Corrosive Soil Characteristics
We measured the soluble sulfate concentration of two (2) representative samples of the
subsoils which will likely be in contact with structural concrete. The sulfate
concentrations measured in the samples varied from 0 to 150 parts per million. ACI rates
the measured concentrations as being a negligible risk of concrete sulfate attack;
therefore Type I cement should be suitable for concrete members on and below grade.
As an added precaution, Type I/II Portland cement could be considered for additional
Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
Lots 15 & 16, Block 3, Evergreen Park Replat
Fort Collins, Colorado
Soilogic # 16-1158
16
sulfate resistance of construction concrete. Foundation concrete should be designed in
accordance with the provisions of the ACI Design Manual, Section 318, Chapter 4.
Drainage
Positive drainage is imperative for satisfactory long-term performance of the proposed
building and associated site improvements. We recommend positive drainage be
developed away from the structure during construction and maintained throughout the
life of the site improvements, with twelve (12) inches of fall in the first 10 feet away from
the building. Shallower slopes could be considered in hardscape areas. In the event that
some settlement of the backfill soils occurs adjacent to the building, the original grade
and associated positive drainage outlined above should be immediately restored.
Care should be taken in the planning of landscaping to avoid features which could result
in the fluctuation of the moisture content of the foundation bearing and/or flatwork
subgrade soils. We recommend watering systems be placed a minimum of 5 feet away
from the perimeter of the site structure and be designed to discharge away from all site
improvements. Gutter systems should be considered to help reduce the potential for
water ponding adjacent to the building with the gutter downspouts, roof drains or
scuppers extended to discharge a minimum of 5 feet away from structural, flatwork and
pavement elements. Water which is allowed to pond adjacent to site improvements can
result in unsatisfactory performance of those improvements over time.
LIMITATIONS
This report was prepared based upon the data obtained from the completed site
exploration, laboratory testing, engineering analysis and any other information discussed.
The completed borings provide an indication of subsurface conditions at the boring
locations only. Variations in subsurface conditions can occur in relatively short distances
away from the borings. This report does not reflect any variations which may occur
across the site or away from the borings. If variations in the subsurface conditions
anticipated become evident, the geotechnical engineer should be notified immediately so
that further evaluation and supplemental recommendations can be provided.
Geotechnical Subsurface Exploration Report
Proposed Schrader Propane Offices
Lots 15 & 16, Block 3, Evergreen Park Replat
Fort Collins, Colorado
Soilogic # 16-1158
17
The scope of services for this project does not include either specifically or by
implication any biological or environmental assessment of the site or identification or
prevention of pollutants or hazardous materials or conditions. Other studies should be
completed if concerns over the potential of such contamination or pollution exist.
The geotechnical engineer should be retained to review the plans and specifications so
that comments can be made regarding the interpretation and implementation of our
geotechnical recommendations in the design and specifications. The geotechnical
engineer should also be retained to provide testing and observation services during
construction to help determine that the design requirements are fulfilled.
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 the generally accepted
standard of care for the profession. No warranties express or implied, are made. The
conclusions and recommendations contained in this report should not be considered valid
in the event that any changes in the nature, design or location of the project as outlined in
this report are planned, unless those changes are reviewed and the conclusions of this
report modified and verified in writing by the geotechnical engineer.
LOG OF BORING B-1
1/1 CME 45
4" CFA
Automatic
BMc
Estimated Swell % Passing
SOIL DESCRIPTION Depth "N" MC DD qu
% Swell @ Pressure # 200 Sieve
(ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%)
5" VEGETATION & TOPSOIL -
1
-
CL LEAN CLAY WITH SAND 2
rust/brown -
very stiff 3 CS 31 10.0 116.5 9000+ 3.5% 4500 29 15 74.2%
-
4
-
5 CS 27 1.0 - N/A - - - - -
-
SP-GP SAND AND GRAVEL 6
rust/brown -
medium dense 7
-
8
-
9
-
10 CS 28 1.6 - N/A - - - - -
-
11
-
12
-
13
-
14
-
15 CS 32 6.1 - N/A - - - - -
BOTTOM OF BORING 15' -
16
-
17
-
18
-
19
-
20
-
21
-
22
-
23
-
24
-
25
-
LOG OF BORING B-2
1/1 CME 45
4" CFA
Automatic
BMc
Estimated Swell % Passing
SOIL DESCRIPTION Depth "N" MC DD qu
% Swell @ Pressure # 200 Sieve
(ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%)
7" VEGETATION & TOPSOIL -
1
-
CL LEAN CLAY WITH SAND 2
rust/brown -
very stiff 3
-
4
-
5 CS 25 2.3 120.5 9000+ None <500 - - -
-
6
-
SP-GP SAND AND GRAVEL 7
rust/brown -
medium dense 8
-
9
-
10 CS 35 4.0 - N/A - - - - -
-
11
-
12
-
13
-
14
-
15 CS 26 6.7 - N/A - - - - -
BOTTOM OF BORING 15' -
16
-
17
-
18
-
19
-
20
-
21
-
22
-
23
-
24
-
25
-
LOG OF BORING B-3
1/1 CME 45
4" CFA
Automatic
BMc
Estimated Swell % Passing
SOIL DESCRIPTION Depth "N" MC DD qu
% Swell @ Pressure # 200 Sieve
(ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%)
5" VEGETATION & TOPSOIL -
1
-
CL LEAN CLAY WITH SAND 2
very stiff -
3 CS 29 15.2 111.5 9000+ 3.7% 6000 - - -
-
4
-
5 CS 15 18.5 108.1 8000 - - - - -
-
6
SP-GP SAND AND GRAVEL -
rust/brown 7
medium dense -
8
-
9
-
10 CS 26 10.1 - N/A - - - - -
BOTTOM OF BORING 10' -
11
-
12
-
13
-
14
-
15
-
16
-
17
-
18
-
19
-
20
-
21
-
22
-
23
-
24
-
25
-
LOG OF BORING B-4
1/1 CME 45
4" CFA
Automatic
BMc
Estimated Swell % Passing
SOIL DESCRIPTION Depth "N" MC DD qu
% Swell @ Pressure # 200 Sieve
(ft) (%) (pcf) (psf) 500 psf (psf) LL PI (%)
6" VEGETATION & TOPSOIL -
1
CL LEAN CLAY WITH SAND -
rust/brown 2
very stiff -
3 CS 25 8.2 106.5 9000+ 1.2% 1500 33 17 84.2%
-
4
-
5 CS 20 1.5 - N/A - - - - -
SP-GP SAND AND GRAVEL -
rust/brown 6
medium dense -
7
-
8
-
9
-
10 CS 19 10.7 - N/A - - - - -
BOTTOM OF BORING 10' -
11
-
12
-
13
-
14
-
15
-
16
-
17
-
18
-
19
-
20
-
21
-
22
-
23
-
24
-
25
-
Liquid Limit 29
Plasticity Index 15
% Passing #200 74.2%
Dry Density 116.5 pcf
Final Moisture 18.7%
% Swell @ 500 psf 3.5%
Swell Pressure 4500 psf
Sample ID: B-1 @ 2'
Sample Description: Brown/Rust Lean Clay with Sand (CL)
Initial Moisture 10.0%
SCHRADER PROPANE OFFICES
LOTS 15 & 16, BLOCK 3, EVERGREEN PARK REPLAT, FORT COLLINS, COLORADO
Project # 16-1158
July 2016
SWELL/CONSOLIDATION TEST SUMMARY
-12
-10
-8
-6
-4
-2
0
2
4
6
8
10
12
10 100 1000 10000 100000
---------
Applied Load (psf)
Liquid Limit -
Plasticity Index -
% Passing #200 -
Dry Density 120.5 pcf
Final Moisture 13.8%
% Swell @ 500 psf None
Swell Pressure <500 psf
Sample ID: B-2 @ 4'
Sample Description: Rust/Brown Silty Sand and Gravel (SM-GM)
Initial Moisture 2.3%
SCHRADER PROPANE OFFICES
LOTS 15 & 16, BLOCK 3, EVERGREEN PARK REPLAT, FORT COLLINS, COLORADO
Project # 16-1158
July 2016
SWELL/CONSOLIDATION TEST SUMMARY
-12
-10
-8
-6
-4
-2
0
2
4
6
8
10
12
10 100 1000 10000 100000
---------
Applied Load (psf)
Liquid Limit -
Plasticity Index -
% Passing #200 -
Dry Density 111.5 pcf
Final Moisture 19.0%
% Swell @ 150 psf 3.7%
Swell Pressure 6000 psf
Sample ID: B-3 @ 2'
Sample Description: Brown/Rust Lean Clay with Sand (CL)
Initial Moisture 15.2%
SCHRADER PROPANE OFFICES
LOTS 15 & 16, BLOCK 3, EVERGREEN PARK REPLAT, FORT COLLINS, COLORADO
Project # 16-1158
July 2016
SWELL/CONSOLIDATION TEST SUMMARY
-12
-10
-8
-6
-4
-2
0
2
4
6
8
10
12
10 100 1000 10000 100000
---------
Applied Load (psf)
Liquid Limit -
Plasticity Index -
% Passing #200 -
Dry Density 106.5 pcf
Final Moisture 19.2%
% Swell @ 150 psf 1.2%
Swell Pressure 1500 psf
Sample ID: B-4 @ 2'
Sample Description: Brown/Rust Lean Clay with Sand (CL)
Initial Moisture 8.2%
SCHRADER PROPANE OFFICES
LOTS 15 & 16, BLOCK 3, EVERGREEN PARK REPLAT, FORT COLLINS, COLORADO
Project # 16-1158
July 2016
SWELL/CONSOLIDATION TEST SUMMARY
-12
-10
-8
-6
-4
-2
0
2
4
6
8
10
12
10 100 1000 10000 100000
---------
Applied Load (psf)
UNIFIED SOIL CLASSIFICATION SYSTEM
Criteria for Assigning Group Symbols and Group Names Using Laboratory TestsA Soil Classification
Group
Symbol
Group NameB
Clean Gravels Cu ! 4 and 1 " Cc " 3E GW Well graded gravelF
Less than 5% finesC Cu
< 4 and/or 1 > Cc > 3E GP Poorly graded gravelF
Fines classify as ML or MH GM Silty gravelF,G, H
Coarse Grained Soils
More than 50% retained
on No. 200 sieve
Gravels
More than 50% of coarse
fraction retained on
No. 4 sieve Gravels with Fines More
than 12% finesC Fines classify as CL or CH GC Clayey gravelF,G,H
Clean Sands Cu ! 6 and 1 " Cc " 3E SW Well graded sandI
Less than 5% finesD Cu
< 6 and/or 1 > Cc > 3E SP Poorly graded sandI
Fines classify as ML or MH SM Silty sandG,H,I
Sands
50% or more of coarse
fraction passes
No. 4 sieve Sands with Fines
More than 12% finesD Fines classify as CL or CH SC Clayey sandG,H,I
Silts and Clays PI > 7 and plots on or above “A” lineJ CL Lean clayK,L,M
Liquid limit less than 50
Inorganic
PI < 4 or plots below “A” lineJ ML SiltK,L,M
Liquid limit - oven
dried
Organic clayK,L,M,N
Fine-Grained Soils
50% or more passes the
No. 200 sieve
Organic
Liquid limit - not
dried
< 0.75 OL
Organic siltK,L,M,O
Inorganic PI plots on or above “A” line CH Fat clayK,L,M
Silts and Clays
Liquid limit 50 or more
PI plots below “A” line MH Elastic siltK,L,M
Organic Liquid limit - oven dried Organic clayK,L,M,P
Liquid limit - not dried
< 0.75 OH
Organic siltK,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-in. (75-mm) sieve
B If field sample contained cobbles or boulders, or both, add “with cobbles
or boulders, or both” to group name.
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 =
GENERAL NOTES
DRILLING & SAMPLING SYMBOLS:
SS: Split Spoon - 1⅜" I.D., 2" O.D., unless otherwise noted HS: Hollow Stem Auger
ST: Thin-Walled Tube – 2.5" O.D., unless otherwise noted PA: Power Auger
RS: Ring Sampler - 2.42" I.D., 3" O.D., unless otherwise noted HA: Hand Auger
CS: California Barrel - 1.92" I.D., 2.5" O.D., unless otherwise noted RB: Rock Bit
BS: Bulk Sample or Auger Sample WB: Wash Boring or Mud Rotary
The number of blows required to advance a standard 2-inch O.D. split-spoon sampler (SS) the last 12 inches of the total 18-inch
penetration with a 140-pound hammer falling 30 inches is considered the “Standard Penetration” or “N-value”. For 2.5” O.D.
California Barrel samplers (CB) the penetration value is reported as the number of blows required to advance the sampler 12
inches using a 140-pound hammer falling 30 inches, reported as “blows per inch,” and is not considered equivalent to the
“Standard Penetration” or “N-value”.
WATER LEVEL MEASUREMENT SYMBOLS:
WL: Water Level WS: While Sampling
WCI: Wet Cave in WD: While Drilling
DCI: Dry Cave in BCR: Before Casing Removal
AB: After Boring ACR: After Casing Removal
Water levels indicated on the boring logs are the levels measured in the borings at the times indicated. Groundwater levels at other
times and other locations across the site could vary. In pervious soils, the indicated levels may reflect the location of groundwater.
In low permeability soils, the accurate determination of groundwater levels may not be possible with only short-term observations.
DESCRIPTIVE SOIL CLASSIFICATION: Soil classification is based on the Unified 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.
FINE-GRAINED SOILS COARSE-GRAINED SOILS BEDROCK
(CB)
Blows/Ft.
(SS)
Blows/Ft.
Consistency
(CB)
Blows/Ft.
(SS)
Blows/Ft.
Relative
Density
(CB)
Blows/Ft.
(SS)
Blows/Ft.
Consistency
< 3 0-2 Very Soft 0-5 < 3 Very Loose < 24 < 20 Weathered
3-5 3-4 Soft 6-14 4-9 Loose 24-35 20-29 Firm
6-10 5-8 Medium Stiff 15-46 10-29 Medium Dense 36-60 30-49 Medium Hard
11-18 9-15 Stiff 47-79 30-50 Dense 61-96 50-79 Hard
19-36 16-30 Very Stiff > 79 > 50 Very Dense > 96 > 79 Very Hard
> 36 > 30 Hard
RELATIVE PROPORTIONS OF SAND AND
GRAVEL
GRAIN SIZE TERMINOLOGY
Descriptive Terms of
Other Constituents
Percent of
Dry Weight
Major Component
of Sample
Particle Size
Trace < 15 Boulders Over 12 in. (300mm)
With 15 – 29 Cobbles 12 in. to 3 in. (300mm to 75 mm)
Modifier > 30 Gravel 3 in. to #4 sieve (75mm to 4.75 mm)
Sand
Silt or Clay
#4 to #200 sieve (4.75mm to 0.075mm)
Passing #200 Sieve (0.075mm)
RELATIVE PROPORTIONS OF FINES PLASTICITY DESCRIPTION
Descriptive Terms of
Other Constituents
Percent of
Dry Weight
Term Plasticity Index
Trace
With
Modifiers
< 5
5 – 12
> 12
Non-plastic
Low
Medium
High
0
1-10
11-30
30+
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.
HIf 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.
26
-
27
-
28
-
29
-
30
SCHRADER PROPANE OFFICES
LOTS 15 & 16, BLOCK 3, EVERGREEN PARK REPLAT, FORT COLLINS, COLORADO
Project # 16-1158
July 2016
Sheet Drilling Rig: Water Depth Information
Start Date 6/22/2016 Auger Type: During Drilling 7'
Finish Date 6/22/2016 Hammer Type: After Drilling 7'
Surface Elev. - Field Personnel: 24 Hours After Drilling 7'
USCS
Sampler
Atterberg Limits
26
-
27
-
28
-
29
-
30
SCHRADER PROPANE OFFICES
LOTS 15 & 16, BLOCK 3, EVERGREEN PARK REPLAT, FORT COLLINS, COLORADO
Project # 16-1158
July 2016
Sheet Drilling Rig: Water Depth Information
Start Date 6/22/2016 Auger Type: During Drilling 7.5'
Finish Date 6/22/2016 Hammer Type: After Drilling 7.5'
Surface Elev. - Field Personnel: 24 Hours After Drilling DCI @ 6.5'
USCS
Sampler
Atterberg Limits
26
-
27
-
28
-
29
-
30
Surface Elev. - Field Personnel: 24 Hours After Drilling 7.5'
USCS
Sampler
Atterberg Limits
Start Date 6/22/2016 Auger Type: During Drilling 7.5'
Finish Date 6/22/2016 Hammer Type: After Drilling 7.5'
SCHRADER PROPANE OFFICES
LOTS 15 & 16, BLOCK 3, EVERGREEN PARK REPLAT, FORT COLLINS, COLORADO
Project # 16-1158
July 2016
Sheet Drilling Rig: Water Depth Information
26
-
27
-
28
-
29
-
30
SCHRADER PROPANE OFFICES
LOTS 15 & 16, BLOCK 3, EVERGREEN PARK REPLAT, FORT COLLINS, COLORADO
Project # 16-1158
July 2016
Sheet Drilling Rig: Water Depth Information
Start Date 6/22/2016 Auger Type: During Drilling 8'
Finish Date 6/22/2016 Hammer Type: After Drilling 8'
Surface Elev. - Field Personnel: 24 Hours After Drilling DCI @ 7.5'
USCS
Sampler
Atterberg Limits