HomeMy WebLinkAboutEXECUTIVE STORAGE FACILITY - Filed SEPD-SURFACE EXPLORATION/PAVEMENT DESIGN REPORT - 2018-03-074396 GREENFIELD DRIVE
WINDSOR, COLORADO 80550
(970) 545-3908 FAX (970) 663-0282
February 27, 2017
Grow Your Storage, LLC
2504 Rigel Drive
Colorado Springs, Colorado 80906
Attn: Mr. Brandon Grebe (brandon@growyourstorage.com)
Re: Subsurface Exploration Report
Executive Storage Facility – 6020 South College Avenue
Fort Collins, Colorado
EEC Project No. 1172005
Mr. Grebe:
Enclosed, herewith, are results of the geotechnical subsurface exploration completed for the
proposed Executive Storage Facility located south of Skyway Drive and west of South College
Avenue at 6020 South College Avenue in Fort Collins, Colorado. Results of the exploration
completed and geotechnical recommendations concerning design and construction of the
proposed building, adjacent pavements, and preliminary recommendations for the City of Fort
Collins roadway are provided within this report. In addition, preliminary percolation rates of site
soils for assistance with the proposed rain garden and detention pond design are provided herein.
This subsurface exploration was performed in general accordance with our proposal dated
February 1, 2017.
In summary, the subsurface soils encountered beneath the surficial topsoil and/or vegetation,
generally consisted of sandy lean clay to clayey sand which extended to the bedrock formation
below. Siltstone/sandstone bedrock was encountered in each of the borings at relatively shallow
depths of approximately ½ to 6 feet below existing site grades and extended to the depths
explored, approximately 10 to 25 feet. At the time of drilling, free water was encountered in
boring B-1 at an approximate depth of 12 feet below site grade while free water was not
encountered in the remaining borings to maximum depths explored. Subsequent groundwater
measurements were performed approximately 24 hours after drilling and free water was observed
in boring B-1 at an approximate depth of 9 feet below existing site grade.
Based on the subsurface conditions encountered in the test borings as well as the anticipated
maximum loading conditions, we recommend the proposed building with garden level walk-out
construction be supported on a conventional spread footing foundation system bearing on and/or
SUBSURFACE EXPLORATION REPORT
EXECUTIVE STORAGE FACILITY
6020 SOUTH COLLEGE AVENUE
FORT COLLINS, COLORADO
EEC PROJECT NO. 1172005
February 27, 2017
INTRODUCTION
The subsurface exploration for the proposed Executive Storage Facility planned for construction at
6020 South College Avenue in Fort Collins, Colorado, has been completed. As a part of this
exploration, six (6) foundation related borings (borings B-1 through B-6), two (2) pavement related
borings (borings B-7 and B-9), one (1) rain garden related boring (boring B-8) and two (2) shallow
soil percolation related borings (borings P-1 and P-2) were drilled at the approximate locations
shown on the boring location diagram included with this report. This exploration was completed in
general accordance with our proposal dated February 1, 2017.
Foundation related soil borings completed within the proposed improvement areas were extended to
depths of approximately 15 to 25 feet below existing site grades, the pavement related soil borings
extended to depths of approximately 10 feet below existing site grades, and the rain garden related
soil boring extended to an approximate depth of 15 feet below existing site grade. In conjunction
with the rain garden soil profile boring, two (2) soil percolation borings were completed within the
proposed rain garden area, borings P-1 and B-2, and extended to depths of approximately 5 and 10
feet below existing site grades, respectively, to assist the design team in designing the rain garden
and detention basin for this project. Individual boring logs are provided with this report. Site
photographs of the property at the time of our exploration are also provided with this report.
We understand the proposed facility would include an approximate 36,000 square foot, 3-story
building with garden level walk-out to the east, a rain garden and detention basin south of the
building, on-site pavement improvements around the building, along with a proposed City of Fort
Collins street section just west of the proposed development area as indicated on the enclosed site
diagram. Foundation loads for the new building are estimated to be light to moderate with
continuous wall loads less than 4 klf and maximum column loads less than 250 kips. Floor loads are
expected to be light.
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EEC Project No. 1172005
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The purpose of this report is to describe the subsurface conditions encountered in the test borings,
analyze and evaluate the test data and provide geotechnical recommendations concerning design and
construction of foundations and support of floor slabs, exterior flatwork, and pavements for the
proposed development, as well as provide preliminary percolation rates for site soils.
EXPLORATION AND TESTING PROCEDURES
The boring locations were established in the field by representatives from Earth Engineering
Consultants, LLC (EEC) by pacing and estimating angles from identifiable site features. Those
approximate boring locations are indicated on the attached boring location diagram. The locations
of the borings should be considered accurate only to the degree implied by the methods used to make
the field measurements. Photographs of the site taken at the time of drilling are included with this
report.
The test borings were completed using a truck mounted, CME-55 drill rig equipped with a hydraulic
head employed in drilling and sampling operations. The boreholes were advanced using 4-inch
nominal diameter continuous flight augers. Samples of the subsurface materials encountered were
obtained using split barrel and California barrel sampling procedures in general accordance with
ASTM Specifications D1586 and D3550, respectively.
In the split barrel and California barrel sampling procedures, standard sampling spoons are advanced
into the ground with a 140-pound hammer falling a distance of 30 inches. The number of blows
required to advance the split barrel and California barrel samplers is recorded and is used to estimate
the in-situ relative density of cohesionless soils and, to a lesser degree of accuracy, the consistency
of cohesive soils and hardness of weathered bedrock. In the California barrel sampling procedure,
relatively intact samples are obtained in removable brass liners. All samples obtained in the field
were sealed and returned to our laboratory for further examination, classification, and testing.
Laboratory moisture content tests were completed on each of the recovered samples. Atterberg
Limits and washed sieve analysis tests were completed on selected samples to evaluate the quantity
and plasticity of fines in the subgrade samples. Swell/consolidation tests were completed on
selected samples to evaluate the potential for the subgrade materials to change volume with variation
in moisture and load. Soluble sulfate tests were completed on selected samples to evaluate potential
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EEC Project No. 1172005
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adverse reactions to site-cast concrete. Results of the outlined tests are indicated herein and/or on
the attached boring logs and summary sheets.
As part of the testing program, all samples were examined in the laboratory by an engineer and
classified in general accordance with the attached General Notes and the Unified Soil Classification
System, based on the soil’s texture and plasticity. The estimated group symbol for the Unified Soil
Classification System is indicated on the boring logs and a brief description of that classification
system is included with this report. Classification of the bedrock was based on visual and tactual
observation of disturbed samples and auger cuttings. Coring and/or petrographic analysis may reveal
other rock types.
SITE AND SUBSURFACE CONDITIONS
The proposed facility is planned for construction south of Skyway Drive and west of South College
Avenue and vacant Outlot B at 6020 South College Avenue. The development parcel is presently
undeveloped with sparse vegetation and topsoil. Ground surface in this area exhibits relief across
the site from west to east on the order of approximately 12 feet and from the southwest to northeast
corners on the order of approximately 20 feet.
Based on results of the field borings and laboratory testing, subsurface conditions can be generalized
as follows. The near surface materials in the test borings generally consisted of a thin layer of
topsoil and/or vegetation. Underlying the thin layer of topsoil and/or vegetation, in general, was
sandy lean clay to clayey sand which extended to depths of approximately 1 to 6 feet below existing
site grades, except for boring B-3. In general, the sandy lean clay to clayey sand overburden
materials demonstrated medium stiff to stiff / medium dense to dense consistency / relative density
and low to moderate bearing capacity characteristics.
Underlying the thin layer of topsoil and/or vegetation in borings B-3 and underlying the sandy lean
clay to clayey sand in the remaining borings, in general, was the siltstone/sandstone bedrock
formation. Siltstone/sandstone bedrock with occasional well cemented sandstone zones was
encountered in each of the borings at depths of approximately ½ to 6 feet below existing site grades
and extended to the depths explored, approximately 10 to 25 feet. The siltstone/sandstone bedrock,
in general, was poorly cemented to cemented at the overburden/bedrock interface, demonstrated
moderate to high bearing capacity characteristics, and low to nil swell potential.
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The stratification boundaries indicated on the boring logs represent the approximate locations of
changes in soil and rock types. In-situ, the transition of materials may be gradual and indistinct.
GROUNDWATER CONDITIONS
Observations were made while drilling and after completion of the borings to detect the presence and
depth to hydrostatic groundwater. At the time of drilling, free water was encountered in boring B-1
at depth of approximately 12 feet, while free water was not observed in the remaining borings to the
depths explored. Boreholes B-1 and B-8 were left open following measurements to allow for
additional water level measurements while the remaining borings were backfilled. Subsequent
groundwater measurements were performed approximately 24 hours after drilling and free water was
observed in boring B-1 at an approximate depth of 9 feet below site grade while boring B-8 was still
dry to the depths drilled. The bore holes were backfilled upon completion of the subsequent water
level measurements; subsequent groundwater measurements were not obtained.
Fluctuations in groundwater levels can occur over time depending on variations in hydrologic
conditions and other conditions not apparent at the time of this report. Longer term monitoring of
water levels in cased wells, which are sealed from the influence of surface water would be required to
more accurately evaluate fluctuations in groundwater levels at the site. We have typically noted
deepest groundwater levels in late winter and shallowest groundwater levels in mid to late summer.
Zones of perched and/or trapped water can be encountered at times throughout the year in more
permeable zones in the subgrade soils and perched water is commonly observed in subgrade soils
immediately above lower permeability bedrock.
ANALYSIS AND RECOMMENDATIONS:
General Considerations
The site appears suitable for the proposed development based on the subsurface conditions observed at
the test boring locations; however, certain precautions will be required in the design and construction
addressing the variable depths to the bedrock formation and penetration of the underlying well
cemented sandstone bedrock lenses.
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Depending upon the depth of excavation for the western portion of the proposed building for basement
/ below grade construction, consideration should be given to installing a perimeter drainage system to
intercept surface water infiltration and/or perched water from impacting the below grade level. In
addition, for portions of the garden level walk-out construction, extension of the foundations to bear on
undisturbed siltstone/sandstone bedrock will be required.
It is anticipated that excavations for the proposed construction can be accomplished with
conventional earthmoving equipment. However, excavations penetrating the well-cemented
sandstone bedrock may require the use of specialized heavy-duty equipment such as a rock hammer
to achieve final design elevations. Consideration should be given to obtaining a unit price for
difficult excavation in the contract documents for the project.
Although evidence of fill materials or underground facilities were 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.
Swell/Consolidation Test Results
As a part of our laboratory testing, we conducted seven (7) swell/consolidation tests on samples of
the site siltstone/sandstone bedrock formation. The swell index values for the samples analyzed
revealed low swell characteristics when inundated with water and pre-loaded at 150 psf, 500 psf, and
1000 psf loads. Results of the laboratory swell tests are indicated in the table below, on the attached
boring logs, and on the enclosed summary sheets.
TABLE I - Swell Consolidation Test Results
Boring
No.
Depth,
ft.
Material Type
In-Situ Moisture
Content, %
Dry Density,
PCF
Inundation
Pressure, psf
Swell Index,
(+/-) %
B-1 4 Siltstone/Sandstone 8.7 113.8 500 (+) 0.3
B-3 9 Sandstone 10.9 124.5 1000 (+) 0.4
B-4 4 Sandstone 6.3 102.5 500 (+) 1.1
B-5 2 Siltstone/Sandstone 5.2 115.8 500 (+) 0.7
B-6 9 Sandstone 9.7 113.8 500 (+) 0.4
B-7 2 Siltstone/Sandstone 7.2 117.2 150 (+) 1.7
B-9 2 Siltstone/Sandstone 11.4 110.0 150 (+) 0.7
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The Colorado Association of Geotechnical Engineers (CAGE) uses the following information to
provide uniformity in terminology between geotechnical engineers to provide a relative correlation risk
performance to measured swell. “The representative percent swell values are not necessarily measured
values; rather, they are a judgment of the swell of the soil and/or bedrock profile likely to influence
slab performance.” Geotechnical engineers use this information to also evaluate the swell potential
risks for foundation performance based on the risk categories.
TABLE II: Recommended Representative Swell Potential Descriptions and Corresponding
Slab Performance Risk Categories
Slab Performance Risk
Category
Representative Percent Swell
(500 psf Surcharge)
Representative Percent Swell
(1000 psf Surcharge)
Low 0 to < 3 0 < 2
Moderate 3 to < 5 2 to < 4
High 5 to < 8 4 to < 6
Very High > 8 > 6
Based on the laboratory test results, the in-situ samples of the siltstone/sandstone bedrock formation
were generally in the low risk range.
Site Preparation
Prior to placement of any fill and/or improvements, we recommend any existing vegetation, topsoil,
and any unsuitable materials be removed from the planned improvement areas. After stripping,
completing all cuts, and removing unacceptable materials/soils, if encountered, and prior to
placement of any fill or site improvements, we recommend the exposed soils be scarified to a depth
of 9-inches, adjusted in moisture content to within ±2% of standard Proctor optimum moisture
content for essentially cohesive materials or to a workable moisture content for essentially
cohesionless materials, and compacted to at least 95% of the material's standard Proctor maximum
dry density as determined in accordance with ASTM Specification D698. If, after the various cuts
as required extend into the undisturbed siltstone/sandstone bedrock, scarification, moisture
conditioning and compaction of the siltstone/sandstone bedrock would not be necessary.
Fill soils required for developing site subgrades, after the initial zone has been prepared, should
consist of approved, low-volume-change materials, which are free from organic matter and debris. It
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is our opinion the on-site sandy lean clay to clayey sand material could be used as general site fill
material, provided adequate moisture treatment and compaction procedures are followed. In
addition, the on-site siltstone/sandstone bedrock could be crushed and used as fill in these areas,
provided fragments larger than 3 inches are removed and adequate moisture treatment and
compaction procedures are followed. Approved structural fill material graded similarly to a CDOT
Class 5, 6 or 7 aggregate base with sufficient fines to prevent ponding of water within the fill could
also be considered. We recommend the fill soils be placed in loose lifts not to exceed 9-inches thick
and adjusted in moisture content and compacted as recommended for the scarified soils.
If fill materials are required for preparation of the interior floor subgrade, approved structural fill
material placed in loose lifts not to exceed 9-inches thick, adjusted to a workable moisture content
and compacted to at least 95% of standard Proctor maximum dry density could be considered.
Care should be exercised after preparation of the subgrades to avoid disturbing the subgrade
materials. Positive drainage should be developed away from the structure to avoid wetting of
subgrade materials.
Foundation Systems – General Considerations
The site appears suitable for the proposed construction based on the results of our field exploration and
our understanding of the proposed building. With the proposed 3-story building with garden level
walk-out to the east, conventional spread footings bearing on undisturbed siltstone/sandstone bedrock or
properly placed and compacted structural fill materials extending to the undisturbed siltstone/sandstone
bedrock should be considered.
Conventional Spread Footing Foundations
Based on the subsurface conditions observed in the test borings and on the anticipated foundation
loads, we recommend supporting the proposed building with garden-level walk-out construction on
undisturbed siltstone/sandstone bedrock formation. For design of footing foundations bearing on
and/or into the poorly cemented to cemented siltstone/sandstone bedrock, we recommend using a net
allowable total load soil bearing pressure not to exceed 5,000 psf. The net bearing pressure refers to
the pressure at foundation bearing level in excess of the minimum surrounding overburden pressure.
Total load should include full dead and live loads.
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In areas where the footing foundation bearing elevations would be above the competent
siltstone/sandstone bedrock or where the bedrock materials have been disturbed, we recommend
those footings be extended to bear on competent in-situ siltstone/sandstone bedrock to reduce the
potential for differential movement of dissimilar materials.
Exterior foundations and foundations in unheated areas should be located at least 30 inches below
adjacent exterior grade to provide frost protection. We recommend formed continuous footings have
a minimum width of 12 inches and isolated column foundations have a minimum width of 24 inches.
Trenched foundations or grade beam foundations should not be used to allow for more thorough
evaluation of anticipated bearing soils at the time of construction.
Care should be taken to thoroughly evaluate anticipated bearing materials at the time of
construction. All footings for the structure should bear on uniform/similar materials to reduce the
potential for differential movement between soil types.
We estimate the long term-settlement of footing foundations designed and constructed as outlined
above would be less than 1-inch.
Seismic Site Classification
The site soil conditions consist of approximately 1 to 6 feet of stiff to very stiff, medium dense to
dense overburden soils overlying poorly cemented to cemented siltstone/sandstone bedrock. For
those site conditions, the 2015 International Building Code indicates a Seismic Site Classification of
C.
Lateral Earth Pressures
The proposed building will be constructed over garden level walk-out construction. In addition, any
site retaining walls or similar structures would also be subject to lateral soil forces. Passive lateral
earth pressures may help resist the driving forces for retaining wall or other similar site structures.
Active lateral earth pressures could be used for design of structures where some movement of the
structure is anticipated, such as retaining walls. The total deflection of structures for design with
active earth pressure is estimated to be on the order of one half of one percent of the height of the
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down slope side of the structure. We recommend at-rest pressures be used for design of structures
where rotation of the walls is restrained, including the below grade parking structure walls. Passive
pressures and friction between the footing and bearing soils could be used for design of resistance to
movement of retaining walls.
Coefficient values for backfill with anticipated types of soils for calculation of active, at-rest and
passive earth pressures are provided in the table below. Equivalent fluid pressure is equal to the
coefficient times the appropriate soil unit weight. As appropriate, buoyant weights and hydrostatic
pressures should be considered. Those coefficient values are based on horizontal backfill with
backfill soils consisting of on-site sandy lean clay / clayey sand subsoils with assumed friction
angles of 25 degrees, processed siltstone/sandstone bedrock with assumed friction angles of 30
degrees, or imported structural fill material with assumed friction angles of at least 35 degrees. The
assumed values should be verified through laboratory testing. For the at-rest and active earth
pressures, slopes away from the structure would result in reduced driving forces with slopes up away
from the structures resulting in greater forces on the walls. The passive resistance would be reduced
with slopes away from the wall. The top 30-inches of soil on the passive resistance side of walls
could be used as a surcharge load; however, should not be used as a part of the passive resistance
value. Frictional resistance is equal to the tangent of the friction angle times the normal force.
Table III: Lateral Earth Pressure Coefficients
Soil Type On-Site Essentially
Cohesive Subsoils
On-Site Processed
Siltstone/Sandstone
Imported Granular
Structural Fill
Wet Unit Weight 115 125 135
Saturated Unit Weight 135 135 140
Friction Angle (ϕ) – (assumed) 25° 30° 35°
Active Pressure Coefficient 0.40 0.33 0.27
At-rest Pressure Coefficient 0.58 0.50 0.43
Passive Pressure Coefficient 2.46 3.0 3.70
Surcharge loads or point loads placed in the backfill can also create additional loads on below grade
walls. Those situations should be designed on an individual basis.
The outlined values do not include factors of safety nor allowances for hydrostatic loads and are
based on assumed friction angles, which should be verified after potential material sources have
been identified.
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Care should be taken to develop appropriate drainage systems behind below grade walls to eliminate
potential for hydrostatic loads developing on the walls. Those systems would likely include
perimeter drain systems extending to sump areas or free outfall where reverse flow cannot occur into
the system. Where necessary, appropriate hydrostatic load values should be used for design.
Floor Slab and Flatwork Subgrades
After stripping and completing all cuts and prior to placement of any fill, floor slabs, or flatwork, we
recommend the in-place materials be proof rolled with heavy construction equipment to help locate
any soft or loose materials in the exposed subgrades.
After stripping and completing all cuts, and prior to placement of floor slabs or flatwork, we
recommend the top 9 inches of the exposed subgrades be scarified, moisture conditioned and
compacted as outlined in the Site Preparation section of this report. We recommend fill materials
required to develop the subgrades consist of approved, low-volume change materials which are free
from organic matter and debris as recommended in the Site Preparation section of this report.
Positive drainage should be developed away from the building and site improvements to reduce
potential for wetting of the bearing soils or subgrades and/or infiltration of water into the building
areas. Typically, a minimum slope away from the building of 1 inch per foot for the first 10 feet is
recommended. Flatter slopes may be used in flatwork areas.
Perimeter Drainage System
The test borings did not encounter groundwater in most of the borings while drilling; however,
groundwater was encountered at a depth of approximately 12 feet in boring B-1 while drilling and at
an approximate depth of 9 feet below present site grade approximately 24 hours after drilling. As
previously discussed, fluctuations can occur in groundwater depths depending on variations in
hydrologic conditions and other conditions not apparent at the time of this report.
The structure is expected to be supported on conventional spread footing foundations bearing on the
siltstone/sandstone bedrock. With potential infiltration of surface water adjacent to the building and
potential perched water in subgrade soils immediately above the lower permeability bedrock, we
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anticipate water could accumulate next to the below grade walls and result in hydrostatic loading on
those walls and, potentially, infiltration of water into the below grade areas. We suggest a perimeter
drain system be installed at the below grade portions of the building to remove surface water
infiltration and/or perched water from the area adjacent to the below grade walls and reduce the
likelihood of development of hydrostatic loads on the walls and/or water infiltration into the below
grade area.
In general, a perimeter drain system would consist of properly sized perforated metal or plastic pipe
placed at the approximate bottom of the spread footing foundations and sloped to drain to a sump
area where accumulated water can be removed without reverse flow into the system. The drain line
should be surrounded by at least 6 inches of free draining granular fill with either the drain line or
granular fill wrapped in an appropriate filter fabric to prevent the intrusions of fines in the system.
Backfill above the drain line should consist of approved, low volume change material.
Installation of the drain system will reduce, not eliminate, the potential for infiltration of surface
and/or groundwater into the below grade areas and development of hydrostatic loads on structure
components. Pumps and other components require periodic inspections and maintenance to
maintain the system in functioning condition.
Pavements
Subgrades for site pavements should be prepared as outlined in the section titled Site Preparation.
In addition, according to Larimer County Urban Area Street Standards (LCUASS), a minimum 3-
foot separation between bottom of pavement section and undisturbed bedrock should be provided.
However, this is not necessarily a jurisdictional project; therefore, this concern may be waived at the
owner’s discretion. If the owner elects to generally comply with LCUASS; depending on final site
grades, overexcavation and replacement of siltstone/sandstone bedrock may be required to maintain
the 3-foot separation. For the portion of the roadway that would be considered City of Fort Collins
roadway, the 3-foot separation would be required. Backfilled materials should be prepared and
placed as outlined in the section titled Site Preparation.
A final pavement design for the City of Fort Collins roadway may not be necessary if the
recommendations provided in this report are followed and construction observation and material
testing is conducted according to City of Fort Collins / LCUASS specifications. The City of Fort
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Collins should determine if a final pavement design in general accordance with LCUASS for the
roadway will be required when the utilities are installed and backfilled, and the roadway is at or near
final subgrade elevation.
We expect the site pavements will include areas designated for low volume automobile and light
truck traffic. We are using an assumed equivalent daily load axle (EDLA) rating of 7 for the on-site
pavements while we are using an assumed EDLA of 25, typical for minor collectors, for the City of
Fort Collins roadway section.
Proof rolling and recompacting the subgrade is recommended immediately prior to placement of the
aggregate road base section and selected pavement section. Soft or weak areas delineated by the
proof rolling operations should be undercut or stabilized in-place to achieve the appropriate
subgrade support. Based on the subsurface conditions encountered at the site, and the laboratory test
results, it is recommended the on-site private drives and parking areas and City of Fort Collins
roadway be designed using an R-value of 10.
Hot Mix Asphalt (HMA) underlain by crushed aggregate base course and non-reinforced concrete
pavement could be considered for the proposed on-site paved sections. HMA pavements may show
rutting and distress in areas of heavy truck traffic or in trash truck loading and turning areas. Concrete
pavements should be considered in those areas. Pavement design methods are intended to provide
structural sections with adequate thickness over a particular subgrade such that wheel loads are reduced
to a level the subgrade can support. The support characteristics of the subgrade for pavement design do
not account for shrink/swell movements of an expansive clay subgrade or consolidation of a wetted
subgrade. Thus, the pavement may be adequate from a structural standpoint, yet still experience
cracking and deformation due to shrink/swell related movement of the subgrade. It is, therefore,
important to minimize moisture changes in the subgrade to reduce shrink/swell movements.
Recommended pavement sections are provided below in the table below. The hot bituminous
pavement (HBP) for on-site pavements could be grading SX (75) or S (75) with PG 58-28 oil, while
the City of Fort Collins roadway section should be S (75) with PG 58-28 oil. The HMA should be
designed in accordance with LCUASS design criteria. HMA should be compacted to achieve 92 to
96% of the mix’s theoretical maximum specific gravity (Rice Value). The aggregate base should be
Class 5 or Class 6 base. Portland cement concrete for pavements should be a pavement design mix
with a minimum 28-day compressive strength of 4000 psi and should be air entrained.
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TABLE IV - RECOMMENDED MINIMUM PAVEMENT SECTIONS
On-Site Pavements City of Fort Collins Roadway
18-kip EDLA
18-kip ESAL
Reliability
Resilient Modulus (R-Value = 10)
PSI Loss
7
51,100
75%
3562 psi
2.5
25
182,500
75%
3562 psi
2.2
Design Structure Number 2.47 3.03
Composite
Hot Mix Asphalt
Aggregate Base Course
Structure Number
4" @ 0.44 = 1.76
7" @ 0.11 = 0.77
(2.53)
5" @ 0.44 = 2.20
8" @ 0.11 = 0.88
(3.08)
PCC (Non-reinforced) – placed on a stable subgrade 5-1/2" --
The recommended pavement sections are minimums and periodic maintenance should be expected.
Longitudinal and transverse joints should be provided as needed in concrete pavements for
expansion/contraction and isolation. The location and extent of joints should be based upon the final
pavement geometry. Sawed joints should be cut in general accordance with ACI recommendations.
All joints should be sealed to prevent entry of foreign material and dowelled where necessary for load
transfer.
Since the site essentially cohesive soils and siltstone/sandstone bedrock have some swell/consolidation
potential, pavements could crack in the future primarily because of the volume change of the soils
when subjected to an increase in moisture content to the subgrade. The cracking, while not desirable,
does not necessarily constitute structural failure of the pavement.
The collection and diversion of surface drainage away from paved areas is critical to the satisfactory
performance of the pavement. Drainage design should provide for the removal of water from paved
areas in order to reduce the potential for wetting of the subgrade soils. Long-term pavement
performance will be dependent upon several factors, including maintaining subgrade moisture levels
and providing for preventive maintenance. The following recommendations should be considered
the minimum:
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The subgrade and the pavement surface should be adequately sloped to promote proper surface
drainage.
Install pavement drainage surrounding areas anticipated for frequent wetting (e.g. garden centers,
wash racks)
Install joint sealant and seal cracks immediately,
Seal all landscaped areas in, or adjacent to pavements to minimize or prevent moisture migration
to subgrade soils;
Placing compacted, low permeability backfill against the exterior side of curb and gutter; and,
Placing curb, gutter, and/or sidewalk directly on approved proof rolled subgrade soils.
Preventive maintenance should be planned and provided for through an on-going pavement
management program. Preventive maintenance activities are intended to slow the rate of pavement
deterioration, and to preserve the pavement investment. Preventive maintenance consists of both
localized maintenance (e.g. crack and joint sealing and patching) and global maintenance (e.g. surface
sealing). Preventive maintenance is usually the first priority when implementing a planned pavement
maintenance program and provides the highest return on investment for pavements. Prior to
implementing any maintenance, additional engineering observation is recommended to determine the
type and extent of preventive maintenance.
Site grading is generally accomplished early in the construction phase. However, as construction
proceeds, the subgrade may be disturbed due to utility excavations, construction traffic, desiccation, or
rainfall. 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, such as but not limited to drying, or excessive rutting. If
disturbance has occurred, pavement subgrade areas should be reworked, moisture conditioned, and
properly compacted to the recommendations in this report immediately prior to paving.
Please note that if during or after placement of the initial lift of pavement, the area is observed to be
yielding under vehicle traffic or construction equipment, it is recommended that EEC be contacted
for additional alternative methods of stabilization, or a change in the pavement section.
Earth Engineering Consultants, LLC
EEC Project No. 1172005
February 27, 2017
Page 15
Water Soluble Sulfates (SO4)
The water soluble sulfate (SO4) testing of the on-site bedrock materials taken during our subsurface
exploration at varying depths are provided in the table below. Based on the reported sulfate content
test results, this report includes a recommendation for the CLASS or TYPE of cement for use for
contact in association with the on-site overburden and bedrock.
TABLE V - Water Soluble Sulfate Test Results
Sample Location Description
Soluble Sulfate Content
(mg/kg)
Soluble Sulfate Content
(%)
B-3, S-2 @ 4’ Sandstone 200 0.02
B-9, S-1 @ 2’ Sandstone 470 0.05
Based on the results as presented in the table above, ACI 318, Section 4.2 indicates the site bedrock
generally has a low risk of sulfate attack on Portland cement concrete. Therefore, Class 0 and Type
I or Type I/II cement could be used for concrete on and below site grades within the bedrock.
Foundation concrete should be designed in accordance with the provisions of the ACI Design
Manual, Section 318, Chapter 4. These results are being compared to the following table.
TABLE VI - Requirements to Protect Against Damage to Concrete by Sulfate Attack from External Sources of Sulfate
Severity of Sulfate exposure Water-soluble sulfate (SO4)
in dry soil, percent
Water-cement ratio,
maximum
Cementitious material
Requirements
Class 0 0.00 to 0.10% 0.45 Class 0
Class 1 0.11 to 0.20% 0.45 Class 1
Class 2 0.21 to 2.00% 0.45 Class 2
Class 3 2.01 of greater 0.45 Class 3
Rain Garden / Detention Pond Overview
We understand a rain garden and detention pond area are proposed near the south end of the proposed
project site. Subsurface conditions within boring B-8 in this area consisted of approximately 6 feet of
sandy lean clay to clayey sand with underlying siltstone/sandstone bedrock to the depth explored,
approximately 15 feet. Groundwater was not encountered to maximum depth of exploration in boring
B-8 or the soil percolation borings P-1 and P2.
Earth Engineering Consultants, LLC
EEC Project No. 1172005
February 27, 2017
Page 16
For this project, we conducted two (2) soil percolation tests, one at P-1 within the near surface
overburden soils to 4 feet below site grades and one at P-2 within the underlying siltstone/sandstone
bedrock up to 9 feet below site grades to develop percolation rates. Soil percolation testing within
the proposed location of the rain garden and detention pond area, conducted for a period of
approximately 150 minutes after an initial “24-hour soaking period”, resulted in a percolation rate
for the overburden soils on the order of 20 minutes/inch and a percolation rate for the underlying
siltstone/sandstone bedrock on the order of 10 minutes/inch.
Other Considerations
Positive drainage should be developed away from the structure with a minimum slope of 1-inch per
foot for the first 10-feet away from the improvements in landscape areas. Flatter slopes could be
used in hardscapes areas although positive drainage should be maintained. Care should be taken in
planning of landscaping adjacent to the building and site improvement areas to avoid features which
would pond water adjacent to those elements. Placement of plants which require irrigation systems
or could result in fluctuations of the moisture content of the subgrade material should be avoided
adjacent to site improvements.
Excavations into the on-site soils may encounter a variety of conditions. If excavations extend into
the underlying cohesionless granular strata, caving soils may be encountered. 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.
Depending upon the depth of any lower level construction, a shoring plan will be necessary to
protect the adjacent sidewall slopes. The project design team should use the subsurface information
provided herein to properly design a mechanism for shoring protection.
GENERAL COMMENTS
The analysis and recommendations presented in this report are based upon the data obtained from
the soil borings performed at the indicated locations and from any other information discussed in this
report. This report does not reflect any variations, which may occur between borings or across the
Earth Engineering Consultants, LLC
EEC Project No. 1172005
February 27, 2017
Page 17
site. The nature and extent of such variations may not become evident until construction. If
variations appear evident, it will be necessary to re-evaluate the recommendations of this report.
It is recommended that the geotechnical engineer be retained to review the plans and specifications
so comments can be made regarding the interpretation and implementation of our geotechnical
recommendations in the design and specifications. It is further recommended that the geotechnical
engineer be retained for testing and observations during earthwork phases to help determine that the
design requirements are fulfilled.
This report has been prepared for the exclusive use for Grow Your Storage, LLC for specific
application to the project discussed and has been prepared in accordance with generally accepted
geotechnical engineering practices. No warranty, express or implied, is made. In the event that any
changes in the nature, design, or location of the project as outlined in this report are planned, the
conclusions and recommendations contained in this report shall not be considered valid unless the
changes are reviewed and the conclusions of this report are modified or verified in writing by the
geotechnical engineer.
Earth Engineering Consultants, LLC
DRILLING AND EXPLORATION
DRILLING & SAMPLING SYMBOLS:
SS: Split Spoon ‐ 13/8" I.D., 2" O.D., unless otherwise noted PS: Piston Sample
ST: Thin‐Walled Tube ‐ 2" O.D., unless otherwise noted WS: Wash Sample
R: Ring Barrel Sampler ‐ 2.42" I.D., 3" O.D. unless otherwise noted
PA: Power Auger FT: Fish Tail Bit
HA: Hand Auger RB: Rock Bit
DB: Diamond Bit = 4", N, B BS: Bulk Sample
AS: Auger Sample PM: Pressure Meter
HS: Hollow Stem Auger WB: Wash Bore
Standard "N" Penetration: Blows per foot of a 140 pound hammer falling 30 inches on a 2‐inch O.D. split spoon, except where noted.
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 Casting Removal
Water levels indicated on the boring logs are the levels measured in the borings at the time indicated. In pervious soils, the indicated
levels may reflect the location of ground water. In low permeability soils, the accurate determination of ground water levels is not
possible with only short term observations.
DESCRIPTIVE SOIL CLASSIFICATION
Soil Classification is based on the Unified Soil Classification
system and the ASTM Designations D‐2488. Coarse Grained
Soils have move than 50% of their dry weight retained on a
#200 sieve; they are described as: boulders, cobbles, gravel or
sand. Fine Grained Soils have less than 50% of their dry weight
retained on a #200 sieve; they are 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 relative in‐
place density and fine grained soils on the basis of their
consistency. Example: Lean clay with sand, trace gravel, stiff
(CL); silty sand, trace gravel, medium dense (SM).
CONSISTENCY OF FINE‐GRAINED SOILS
Unconfined Compressive
Strength, Qu, psf Consistency
< 500 Very Soft
500 ‐ 1,000 Soft
1,001 ‐ 2,000 Medium
2,001 ‐ 4,000 Stiff
4,001 ‐ 8,000 Very Stiff
8,001 ‐ 16,000 Very Hard
RELATIVE DENSITY OF COARSE‐GRAINED SOILS:
N‐Blows/ft Relative Density
0‐3 Very Loose
4‐9 Loose
10‐29 Medium Dense
30‐49 Dense
50‐80 Very Dense
80 + Extremely Dense
PHYSICAL PROPERTIES OF BEDROCK
DEGREE OF WEATHERING:
Slight Slight decomposition of parent material on
joints. May be color change.
Moderate Some decomposition and color change
throughout.
High Rock highly decomposed, may be extremely
broken.
Group
Symbol
Group Name
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
Fines classify as ML or MH GM Silty gravel
G,H
Fines Classify as CL or CH GC Clayey Gravel
F,G,H
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
Fines classify as ML or MH SM Silty sand
G,H,I
Fines classify as CL or CH SC Clayey sand
G,H,I
inorganic PI>7 and plots on or above "A" Line CL Lean clay
K,L,M
PI<4 or plots below "A" Line ML Silt
K,L,M
organic Liquid Limit - oven dried Organic clay
K,L,M,N
Liquid Limit - not dried Organic silt
K,L,M,O
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 Organic clay
K,L,M,P
Liquid Limit - not dried Organic silt
K,L,M,O
Highly organic soils PT Peat
(D30)2
D10 x D60
GW-GM well graded gravel with silt NPI≥4 and plots on or above "A" line.
GW-GC well-graded gravel with clay OPI≤4 or plots below "A" line.
GP-GM poorly-graded gravel with silt PPI plots on or above "A" line.
GP-GC poorly-graded gravel with clay QPI plots below "A" line.
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
Earth Engineering Consultants, LLC
IIf soil contains >15% gravel, add "with gravel" to
group name
JIf Atterberg limits plots shaded area, soil is a CL-
ML, Silty clay
Unified Soil Classification System
EXECUTIVE STORAGE FACILITY
6020 S COLLEGE AVENUE
FORT COLLINS, COLORADO
EEC PROJECT NO. 1172005
FEBRUARY 2017
1
2
B-7
B-1 B-2
B-3
B-5 B-6
B-4
B-8
P-1 P-2
B-9
Boring Location Diagram
Executive Storage
6020 S College Ave - Fort Collins, Colorado
EEC Project Number: 1172005
February 2017
EARTH ENGINEERING CONSULTANTS, LLC
B-1 thru B-6:
Foundation Related
Borings
1
Legend
Site Photos
(Photos taken in approximate
location, in direction of arrow)
B-7 & B-9: Pavement
Related Borings
B-8: Rain Garden
Related Boring
P-1 & P-2: Soil
Percolation /
Infiltration Borings
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
SPARSE VEGETATION _ _
1
SANDY LEAN CLAY (CL) / CLAYEY SAND (SC) _ _
brown 2
medium stiff to stiff / medium dense to dense _ _
3
_ _
4
_ _
CS 5 50/8.5" 4500 8.7 105.3 NL NP 22.7 1000 psf 0.3%
SANDSTONE _ _
brown / rust 6
poorly cemented to cemented _ _
7
_ _
8
_ _
9
_ _
SS 10 50/6" -- 11.1
_ _
11
_ _
12
_ _
13
_ _
14
_ _
CS 15 50/1" 9000+ 16.5
_ _
16
_ _
17
_ _
18
_ _
19
_ _
SS 20 50/2" 8000 17.3
_ _
BOTTOM OF BORING DEPTH 20.5' 21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
SOIL DESCRIPTION
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
TOPSOIL & VEGETATION _ _
1
SANDY LEAN CLAY (CL) / CLAYEY SAND (SC) _ _
brown 2
medium stiff to stiff / medium dense to dense _ _
3
_ _
4
SANDSTONE _ _
brown / rust CS 5 50/1.5" -- 2.6
poorly cemented to cemented _ _
6
_ _
7
_ _
8
_ _
9
brown / rust _ _
SS 10 50/4" -- 9.5
_ _
11
_ _
12
_ _
13
_ _
14
_ _
CS 15 50/4" 7000 10.1 100.9
_ _
16
_ _
17
_ _
18
_ _
19
grey _ _
SS 20 50/2.5" -- 10.9
_ _
21
_ _
22
_ _
23
_ _
24
_ _
CS 25 Bounce -- 4.5
BOTTOM OF BORING DEPTH 25.0' _ _
Earth Engineering Consultants, LLC
SOIL DESCRIPTION
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
SPARSE VEGETATION _ _
1
SANDSTONE _ _
brown / rust 2
weathered / poorly cemented to cemented _ _
CS 3 50/3" -- 4.9 100.5
_ _
4
_ _
SS 5 50/5" 4000 10.4
_ _
6
_ _
7
_ _
8
_ _
9
_ _ % @ 1000 psf
CS 10 50/3" 9000+ 10.9 108.1 2500 psf 0.4%
_ _
11
_ _
12
_ _
13
_ _
14
_ _
SS 15 50/3" 1000 10.4
_ _
BOTTOM OF BORING DEPTH 15.5' 16
_ _
17
_ _
18
_ _
19
_ _
20
_ _
21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
SOIL DESCRIPTION
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
SPARSE VEGETATION _ _
SANDY LEAN CLAY (CL) / CLAYEY SAND (SC) 1
brown _ _
medium stiff to stiff / medium dense to dense 2
_ _
SANDSTONE 3
brown / rust _ _
poorly cemented to cemented 4
_ _
CS 5 50/5" 2500 6.3 93.3 1700 psf 1.1%
_ _
6
cemented lense _ _
7
_ _
8
_ _
9
_ _
SS 10 50/4" 1000 11.3
_ _
11
_ _
12
_ _
13
_ _
14
_ _
CS 15 50/3.5" 9000+ 12.3 108.9
BOTTOM OF BORING DEPTH 15.0' _ _
16
_ _
17
_ _
18
_ _
19
_ _
20
_ _
21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
SOIL DESCRIPTION
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
SPARSE VEGETATION _ _
SANDY LEAN CLAY (CL) / CLAYEY SAND (SC) 1
brown _ _
medium stiff to stiff / medium dense to dense 2
_ _
CS 3 50/10" 9000+ 5.2 117.2 26 6 21.0 1800 psf 0.7%
SILTSTONE / SANDSTONE _ _
brown / rust 4
poorly cemented to cemented _ _
SS 5 Bounce -- 1.8
_ _
6
with intermittent cemented lenses _ _
7
_ _
8
_ _
9
_ _
CS 10 50/3" 9000+ 10.8 112.6
_ _
11
_ _
12
_ _
13
_ _
14
_ _
SS 15 50/2" -- 9.7
_ _
16
_ _
17
_ _
18
_ _
19
_ _
CS 20 50/2" 9000+ 10.7 110.1
BOTTOM OF BORING DEPTH 20.0' _ _
21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
SOIL DESCRIPTION
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
SPARSE VEGETATION _ _
1
SANDY LEAN CLAY (CL) / CLAYEY SAND (SC) _ _
brown 2
medium stiff to stiff / medium dense to dense _ _
with calcareous deposits CS 3 27 9000+ 5.7 102.2
_ _
4
*intermittent SILTY SAND lense _ _
SS 5 14 7500 7.8
_ _
6
SANDSTONE _ _
brown / rust 7
poorly cemented to cemented _ _
8
_ _
9
_ _
CS 10 50/3" 9000+ 9.7 110.8 1000 psf 0.4%
_ _
11
_ _
12
_ _
13
_ _
14
_ _
SS 15 50/2" 9000+ 11.6
_ _
16
_ _
17
_ _
18
_ _
19
grey _ _
CS 20 50/2" 9000+ 10.7 130.2
BOTTOM OF BORING DEPTH 20.0' _ _
21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
SOIL DESCRIPTION
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
SPARSE VEGETATION _ _
SANDY LEAN CLAY (CL) / CLAYEY SAND (SC) 1
brown _ _
medium stiff to stiff / medium dense to dense 2
with calcareous deposits _ _ % @ 150 psf
CS 3 50/10" 9000+ 7.2 113.5 NL NP 17.1 2000 psf 1.7%
SANDSTONE _ _
brown / rust 4
poorly cemented to cemented _ _
SS 5 50/3" 8000 8.4
_ _
6
_ _
7
_ _
8
_ _
9
_ _
SS 10 50/1" -- 11.3
_ _
BOTTOM OF BORING DEPTH 10.5' 11
_ _
12
_ _
13
_ _
14
_ _
15
_ _
16
_ _
17
_ _
18
_ _
19
_ _
20
_ _
21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
SOIL DESCRIPTION
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
SPARSE VEGETATION _ _
1
SANDY LEAN CLAY (CL) / CLAYEY SAND (SC) _ _
brown 2
medium stiff to stiff / medium dense to dense _ _
with calcareous deposits 3
_ _
4
_ _
CS 5 22 8000 6.3 103.4 32 18 36.9
_ _
6
_ _
SANDSTONE 7
brown / rust _ _
poorly cemented to cemented 8
_ _
9
_ _
SS 10 50/3" 7000 8.9
cemented lense _ _
11
_ _
12
_ _
13
_ _
14
_ _
CS 15 50/1.5" 9000+ 10.7
BOTTOM OF BORING DEPTH 15.0' _ _
16
_ _
17
_ _
18
_ _
19
_ _
20
_ _
21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
SOIL DESCRIPTION
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
SPARSE VEGETATION _ _
SANDY LEAN CLAY (CL) / CLAYEY SAND (SC), brown 1
_ _
SANDSTONE 2
brown / rust _ _ % @ 150 psf
poorly cemented to cemented CS 3 50/6" 7500 11.4 110.6 NL NP 17.3 750 psf 0.7%
_ _
4
_ _
SS 5 50/5" -- 13.6
_ _
6
_ _
7
_ _
8
_ _
9
_ _
SS 10 50/1.5" -- 12.3
_ _
BOTTOM OF BORING DEPTH 10.5' 11
_ _
12
_ _
13
_ _
14
_ _
15
_ _
16
_ _
17
_ _
18
_ _
19
_ _
20
_ _
21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
SOIL DESCRIPTION
Project:
Location:
Project #:
Date:
Executive Storage Facility
Fort Collins, Colorado
1172005
February 2017
Beginning Moisture: 8.7% Dry Density: 113.8 pcf Ending Moisture: 20.7%
Swell Pressure: 1000 psf % Swell @ 500: 0.3%
Sample Location: Boring 1, Sample 1, Depth 4'
Liquid Limit: NL Plasticity Index: NP % Passing #200: 22.7%
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown / Rust Siltstone / Sandstone
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Consolidatio Swell
Water Added
Project:
Location:
Project #:
Date:
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown / Rust Sandstone
Sample Location: Boring 3, Sample 3, Depth 9'
Liquid Limit: - - Plasticity Index: - - % Passing #200: - -
Beginning Moisture: 10.9% Dry Density: 124.5 pcf Ending Moisture: 14.1%
Swell Pressure: 2500 psf % Swell @ 1000: 0.4%
Executive Storage Facility
Fort Collins, Colorado
1172005
February 2017
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Consolidatio Swell
Water Added
Project:
Location:
Project #:
Date:
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown / Rust Sandstone
Sample Location: Boring 4, Sample 1, Depth 4'
Liquid Limit: - - Plasticity Index: - - % Passing #200: - -
Beginning Moisture: 6.3% Dry Density: 102.5 pcf Ending Moisture: 22.1%
Swell Pressure: 1700 psf % Swell @ 500: 1.1%
Executive Storage Facility
Fort Collins, Colorado
1172005
February 2017
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Consolidatio Swell
Water Added
Project:
Location:
Project #:
Date:
Executive Storage Facility
Fort Collins, Colorado
1172005
February 2017
Beginning Moisture: 5.2% Dry Density: 115.8 pcf Ending Moisture: 16.8%
Swell Pressure: 1800 psf % Swell @ 500: 0.7%
Sample Location: Boring 5, Sample 1, Depth 2'
Liquid Limit: 26 Plasticity Index: 6 % Passing #200: 21.0%
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown / Rust Siltstone / Sandstone
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Consolidatio Swell
Water Added
Project:
Location:
Project #:
Date:
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown / Rust Sandstone
Sample Location: Boring 6, Sample 3, Depth 9'
Liquid Limit: - - Plasticity Index: - - % Passing #200: - -
Beginning Moisture: 9.7% Dry Density: 113.8 pcf Ending Moisture: 18.3%
Swell Pressure: 1000 psf % Swell @ 500: 0.4%
Executive Storage Facility
Fort Collins, Colorado
1172005
February 2017
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Consolidatio Swell
Water Added
Project:
Location:
Project #:
Date:
Executive Storage Facility
Fort Collins, Colorado
1172005
February 2017
Beginning Moisture: 7.2% Dry Density: 117.2 pcf Ending Moisture: 18.5%
Swell Pressure: 2000 psf % Swell @ 150: 1.7%
Sample Location: Boring 7, Sample 1, Depth 2'
Liquid Limit: NL Plasticity Index: NP % Passing #200: 17.1%
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown / Rust Siltstone / Sandstone
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Consolidatio Swell
Water Added
Project:
Location:
Project #:
Date:
Executive Storage Facility
Fort Collins, Colorado
1172005
February 2017
Beginning Moisture: 11.4% Dry Density: 110 pcf Ending Moisture: 18.8%
Swell Pressure: 750 psf % Swell @ 150: 0.7%
Sample Location: Boring 9, Sample 1, Depth 2'
Liquid Limit: NL Plasticity Index: NP % Passing #200: 17.3%
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown / Rust Siltstone / Sandstone
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Consolidatio Swell
Water Added
EXECUTIVE STORAGE FACILITY
FORT COLLINS, COLORADO
PROJECT NO: 1172005 LOG OF BORING B-9 FEBRUARY 2017
SHEET 1 OF 1 WATER DEPTH
START DATE 2/7/2017 WHILE DRILLING None
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 2/7/2017 AFTER DRILLING N/A
A-LIMITS SWELL
EXECUTIVE STORAGE FACILITY
FORT COLLINS, COLORADO
PROJECT NO: 1172005 LOG OF BORING B-8 FEBRUARY 2017
SHEET 1 OF 1 WATER DEPTH
START DATE 2/7/2017 WHILE DRILLING None
SURFACE ELEV N/A 24 HOUR None
FINISH DATE 2/7/2017 AFTER DRILLING N/A
A-LIMITS SWELL
EXECUTIVE STORAGE FACILITY
FORT COLLINS, COLORADO
PROJECT NO: 1172005 LOG OF BORING B-7 FEBRUARY 2017
SHEET 1 OF 1 WATER DEPTH
START DATE 2/7/2017 WHILE DRILLING None
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 2/7/2017 AFTER DRILLING N/A
A-LIMITS SWELL
EXECUTIVE STORAGE FACILITY
FORT COLLINS, COLORADO
PROJECT NO: 1172005 LOG OF BORING B-6 FEBRUARY 2017
SHEET 1 OF 1 WATER DEPTH
START DATE 2/7/2017 WHILE DRILLING None
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 2/7/2017 AFTER DRILLING N/A
A-LIMITS SWELL
EXECUTIVE STORAGE FACILITY
FORT COLLINS, COLORADO
PROJECT NO: 1172005 LOG OF BORING B-5 FEBRUARY 2017
SHEET 1 OF 1 WATER DEPTH
START DATE 2/7/2017 WHILE DRILLING None
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 2/7/2017 AFTER DRILLING N/A
A-LIMITS SWELL
EXECUTIVE STORAGE FACILITY
FORT COLLINS, COLORADO
PROJECT NO: 1172005 LOG OF BORING B-4 FEBRUARY 2017
SHEET 1 OF 1 WATER DEPTH
START DATE 2/7/2017 WHILE DRILLING None
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 2/7/2017 AFTER DRILLING N/A
A-LIMITS SWELL
EXECUTIVE STORAGE FACILITY
FORT COLLINS, COLORADO
PROJECT NO: 1172005 LOG OF BORING B-3 FEBRUARY 2017
SHEET 1 OF 1 WATER DEPTH
START DATE 2/7/2017 WHILE DRILLING None
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 2/7/2017 AFTER DRILLING N/A
A-LIMITS SWELL
EXECUTIVE STORAGE FACILITY
FORT COLLINS, COLORADO
PROJECT NO: 1172005 LOG OF BORING B-2 FEBRUARY 2017
SHEET 1 OF 1 WATER DEPTH
START DATE 2/7/2017 WHILE DRILLING None
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 2/7/2017 AFTER DRILLING N/A
A-LIMITS SWELL
EXECUTIVE STORAGE FACILITY
FORT COLLINS, COLORADO
PROJECT NO: 1172005 LOG OF BORING B-1 FEBRUARY 2017
SHEET 1 OF 1 WATER DEPTH
START DATE 2/7/2017 WHILE DRILLING 12'
SURFACE ELEV N/A 24 HOUR 9'
FINISH DATE 2/7/2017 AFTER DRILLING N/A
A-LIMITS SWELL
Soil Classification
Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests
Sands 50% or more
coarse fraction
passes No. 4 sieve
Fine-Grained Soils
50% or more passes
the No. 200 sieve
<0.75 OL
Gravels with Fines
more than 12%
fines
Clean Sands Less
than 5% fines
Sands with Fines
more than 12%
fines
Clean Gravels Less
than 5% fines
Gravels more than
50% of coarse
fraction retained on
No. 4 sieve
Coarse - Grained Soils
more than 50%
retained on No. 200
sieve
CGravels with 5 to 12% fines required dual symbols:
Kif soil contains 15 to 29% plus No. 200, add "with sand"
or "with gravel", whichever is predominant.
<0.75 OH
Primarily organic matter, dark in color, and organic odor
ABased on the material passing the 3-in. (75-mm)
sieve
ECu=D60/D10 Cc=
HIf fines are organic, add "with organic fines" to
group name
LIf soil contains ≥ 30% plus No. 200 predominantly sand,
add "sandy" to group name.
MIf soil contains ≥30% plus No. 200 predominantly gravel,
add "gravelly" to group name.
DSands with 5 to 12% fines require dual symbols:
BIf field sample contained cobbles or boulders, or
both, add "with cobbles or boulders, or both" to
group name. FIf soil contains ≥15% sand, add "with sand" to
GIf fines classify as CL-ML, use dual symbol GC-
CM, or SC-SM.
Silts and Clays
Liquid Limit less
than 50
Silts and Clays
Liquid Limit 50 or
more
0
10
20
30
40
50
60
0 10 20 30 40 50 60 70 80 90 100 110
PLASTICITY INDEX (PI)
LIQUID LIMIT (LL)
ML OR OL
MH OR OH
For Classification of fine-grained soils and
fine-grained fraction of coarse-grained
soils.
Equation of "A"-line
Horizontal at PI=4 to LL=25.5
then PI-0.73 (LL-20)
Equation of "U"-line
Vertical at LL=16 to PI-7,
then PI=0.9 (LL-8)
CL-ML
HARDNESS AND DEGREE OF CEMENTATION:
Limestone and Dolomite:
Hard Difficult to scratch with knife.
Moderately Can be scratched easily with knife.
Hard Cannot be scratched with fingernail.
Soft Can be scratched with fingernail.
Shale, Siltstone and Claystone:
Hard Can be scratched easily with knife, cannot be
scratched with fingernail.
Moderately Can be scratched with fingernail.
Hard
Soft Can be easily dented but not molded with
fingers.
Sandstone and Conglomerate:
Well Capable of scratching a knife blade.
Cemented
Cemented Can be scratched with knife.
Poorly Can be broken apart easily with fingers.
Cemented