HomeMy WebLinkAboutPOUDRE GARAGE - BDR160007 - SUBMITTAL DOCUMENTS - ROUND 2 - GEOTECHNICAL (SOILS) REPORTGEOTECHNICAL EXPLORATION REPORT
POUDRE GARAGE – 148 REMINGTON STREET
FORT COLLINS, COLORADO
EEC PROJECT NO. 1162021
Prepared for:
Poudre Garage, LLC
C/o Diehl Management
148 Remington Street
Fort Collins, Colorado 80524
Attn: Ms. Tricia Diehl (tricia@diehlmanagement.com)
Prepared by:
Earth Engineering Consultants, LLC
4396 Greenfield Drive
Windsor, Colorado 80550
4396 GREENFIELD DRIVE
WINDSOR, COLORADO 80550
(970) 545-3908 FAX (970) 663-0282
www.earth-engineering.com
March 30, 2016
Poudre Garage, LLC
C/o Diehl Management
148 Remington Street
Fort Collins, Colorado 80524
Attn: Ms. Tricia Diehl (tricia@diehlmanagement.com)
Re: Geotechnical Exploration Report
Poudre Garage – 148 Remington Street
Fort Collins, Colorado
EEC Project No. 1162021
Ms. Diehl:
Enclosed herewith, are the results of the subsurface exploration completed by Earth Engineering
Consultants, LLC for the referenced project. For this exploration, three (3) soil borings were
extended to depths of approximately 30 feet below existing site grades within the proposed
building location. This subsurface exploration was completed in general accordance with our
proposal dated February 17, 2016.
In summary, the subsurface conditions encountered in the test borings generally consisted of
approximately 6 inches of a surficial gravel layer underlain by an apparent fill material which
extended to depths of approximately 2 to 5 feet below site grades. The fill generally consisted of
clayey sand with gravel. Underlying the apparent fill was native clayey sand, which was
underlain by silty to poorly graded sand and gravel encountered at approximate depths of 8 to 9
feet and extended to the underlying siltstone/sandstone bedrock. The bedrock formation was
encountered at depths of approximately 16 to 17 feet and extended to the depths explored,
approximately 30 feet. The near surface soils showed generally low swell potential with light to
moderate bearing capacity characteristics. The underlying silty to poorly graded sand and gravel
showed moderate bearing capacity characteristics while the underlying siltstone/sandstone
bedrock showed moderate to high bearing capacity characteristics. Groundwater was not
observed in any of the borings at the time of drilling to the maximum depths explored,
approximately 30 feet below site grades. After completing the drilling operations groundwater
was observed in borings B-1 and B-2 at approximate depths of 19 and 16 feet, respectively.
Groundwater was not observed in boring B-3. The borings were backfilled upon completion of
GEOTECHNICAL EXPLORATION REPORT
POUDRE GARAGE – 148 REMINGTON STREET
FORT COLLINS, COLORADO
EEC PROJECT NO. 1162021
March 30, 2016
INTRODUCTION
The geotechnical subsurface exploration for the proposed development planned for construction
northeast of the intersection of Remington Street and Oak Street and east of the existing structure
located at 148 Remington Street in Fort Collins, Colorado has been completed. As a part of this
exploration, three (3) foundation related borings (borings B-1 through B-3) were drilled at the
approximate locations as shown on the boring location diagram included with this report. The soil
borings completed within the proposed building footprint were extended to depths of approximately
30 feet below existing site grades. 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 development involves the construction of an approximate 2,604 square
foot in plan line dimensions, 4-story, slab-on-grade building. The bottom level is expected to
include new storage areas, retail space, lobby area, and garage with the upper levels expected to be
apartments. It is our understanding the 2nd and 3rd stories will have walk out patios that extend to the
adjacent roof of the existing building to the west at 148 Remington Street. Foundation loads for the
structure are expected to be moderate with continuous wall loads on the order of 4 kips per lineal
foot and individual column loads on the order of 60 kips. Floor loads are expected to be light. Small
grade changes are expected to develop site grades for the proposed improvements.
The purpose of this report is to describe the subsurface conditions encountered in the test borings,
analyze and evaluate the field and laboratory test data and provide geotechnical recommendations
concerning design and construction of foundations and support of floor slabs, and exterior flatwork
for the proposed development.
EXPLORATION AND TESTING PROCEDURES
The boring locations were established in the field by a representative of Earth Engineering
Consultants, LLC (EEC) by pacing and estimating angles from identifiable site features based on the
specific boring locations identified by JVA, Inc., the project’s structural engineers. Based on
“Google Earth” the ground surface elevations with gravel parking areas where the 3 borings were
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March 30, 2016
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completed is approximately 4987 (+/-). The locations of the borings should be considered accurate
only to the degree implied by the methods used. Photographs of the site at the time of drilling are
included with this report and the approximate locations of the borings are indicated on the attached
boring location diagram.
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 in the
foundation related borings 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 by means of 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 undisturbed samples are obtained in removable brass liners. All samples
obtained in the field were sealed and returned to the 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. 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. Water soluble sulfate was determined on select samples of site overburden and
underlying bedrock materials to estimate the potential for sulfate attack on site-cast Portland cement
concrete. Results of the outlined tests are indicated on the attached boring logs and summary sheets.
As part of the testing program, all samples were examined in the laboratory 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 auger
cuttings and disturbed samples. Coring and/or petrographic analysis may reveal other rock types.
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SITE AND SUBSURFACE CONDITIONS
The proposed development is planned for construction northeast of the intersection of Remington
Street and West Oak Street and east of the existing structure at 148 Remington Street. The
development parcel is presently a gravel surfaced area used as parking for 148 Remington Street.
Ground surface in this area is relatively flat.
The near surface materials in the test borings generally consisted of approximately 6 inches of
gravel. Apparent fill, on the order of 2 to 5 feet, was observed in the borings underlying the gravel
surface materials and was generally classified as clayey sand with gravels. Underlying the gravel
and underlying the apparent fill was relatively dry to moist, loose to medium dense clayey sand. The
slightly cohesive soils exhibited generally low swell potential in laboratory testing at in-situ
moisture and density. The slightly cohesive soils extended to depths of approximately 8 to 9 feet
and were underlain by silty to poorly graded sand and gravel which extended to depths of
approximately 16 to 17 feet, and were underlain by siltstone/sandstone bedrock. The silty to poorly
graded sand and gravel was relatively dry, dense to very dense and exhibited no plasticity and
moderate bearing capacity characteristics. The siltstone/sandstone bedrock was encountered in the
borings at approximate depths of 16 to 17 feet and extended to the depths explored, approximately
30 feet below existing site grades. The siltstone/sandstone bedrock exhibited low to no plasticity,
moderate to high bearing capacity characteristics, and low swell potential.
The stratification boundaries indicated on the boring logs represent the approximate locations of
changes in soil and bedrock 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 groundwater was not observed in any
of the borings. After drilling, groundwater levels were obtained by National Inspection Services
(NIS) personnel conducting a Limited Phase II Environmental Subsurface Investigation and
provided them to EEC personnel. After drilling groundwater levels for borings B-1 and B-3 were
detected at 19 and 16 feet, respectively. Groundwater was not observed in boring B-3. The borings
were backfilled upon completion of the water sampling conducted by NIS; therefore subsequent
groundwater measurements were not performed.
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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. Perched groundwater is
commonly observed in subgrade soils overlying less permeable bedrock. We have typically noted
deepest groundwater levels in late winter and shallowest groundwater levels in mid to late summer.
ANALYSIS AND RECOMMENDATIONS
Swell – Consolidation Test Results
The swell-consolidation test is performed to evaluate the swell or collapse potential of soils or bedrock
to help determine foundation, floor slab, and pavement design criteria. In this test, relatively
undisturbed samples obtained directly from the California barrel sampler are placed in a laboratory
apparatus and inundated with water under a predetermined load. All inundated samples are monitored
for swell and consolidation. The swell-index is the resulting amount of swell or collapse after
inundation, expressed as a percent of the sample’s initial thickness. After the initial inundation period,
additional incremental loads are applied to evaluate the swell pressure and consolidation.
For this assessment, we conducted four (4) swell-consolidation tests on samples recovered from
various intervals/depths. The swell index values for the samples analyzed in the overburden clayey
sand soils revealed generally low swell characteristics of approximately (-) 0.1% to (+) 0.1% at 150,
500, and 1000 psf dead loads. The laboratory swell-consolidation test results are summarized in the
table below and the swell test data sheets are provided with this report.
TABLE I – Summary of Swell Test Results
Boring
No.
Depth
(ft) Material Type
Swell Consolidation Test Results
Dry
Density,
(pcf)
In-Situ
Moisture
Content
(%)
Inundation
Pressure
(psf)
Swell
Index
(%)
Swell
Pressure
(psf)
1 2’ Clayey Sand (SC) 117.4 15.3 150 (+/-) 0.0 <150
2 4’ Clayey Sand (SC) 117.4 12.8 500 (-) 0.1 <500
2 24’ Siltstone/Sandstone 113.3 12.9 1000 (+) 0.1 1400
3 4’ Clayey Sand (SC) 118.2 11.3 500 (+/-) 0.0 <500
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Colorado Association of Geotechnical Engineers (CAGE) uses the following information presented
below to provide uniformity in terminology between geotechnical engineers to provide a relative
correlation of performance risk 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 swell samples analyzed for this project at current moisture
contents and dry densities conditions were generally in the low to nil range.
Site Preparation
Prior to placement of any fill and/or improvements, we recommend any existing undocumented fill,
and any unsuitable materials be removed from the planned improvement areas. In the areas of any
existing improvements to be removed, all existing elements should be removed. Care should be
taken to remove any previously placed fill material with unknown origin or compaction verification.
After removal of all existing fill materials and any existing improvements within the planned
development area, as well as removal of unacceptable or unsuitable subsoils and removal of
overexcavation materials, and prior to placement of fill the exposed soils should be scarified to a
depth of 9 inches, adjusted in moisture content to within (+/-) 2% of standard Proctor optimum
moisture content and compacted to at least 95% of the material's standard Proctor maximum dry
density as determined in accordance with ASTM Specification D698.
Fill materials used to replace the overexcavated zone and establish grades in the foundation, floor
slab and flatwork areas, after the initial zone has been prepared as recommended above, should
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consist of approved on-site clayey sand, similar import material or approved structural fill material
which is free from organic matter and debris. If on-site slightly cohesive subsoils or similar import
materials are used as engineered fill, they should be placed in maximum 9-inch loose lifts, moisture
conditioned and compacted as recommended for the scarified soils. If structural fill materials are
used they should be graded similarly to a CDOT Class 5, 6 or 7 aggregate base with sufficient fines
to prevent ponding of water within the fill. Structural fill material should be 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 as determined by ASTM Specification D698.
Fill soils to develop the floor slab and flatwork subgrades should consist of approved, low-volume-
change materials, which are free from organic matter and debris. It is our opinion the on-site near
surface soils, similar import fill soils, or import structural fill could be used as fill in these areas,
provided adequate moisture treatment and compaction procedures are followed. We recommend 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 and/or backfill soils. If the site clayey sand soils are
used as fill material, care will be needed to maintain the recommended moisture content and
densities prior to and during construction of overlying improvements. Subgrade soils allowed to
become dry or densified by construction traffic may show increased swell potential.
Care should be exercised after preparation of the subgrades to avoid disturbing the subgrade
materials. Positive drainage should be developed away from the structures and flatwork to avoid
wetting of subgrade materials. Subgrade materials becoming wet subsequent to construction of the
site improvements can result in unacceptable performance.
Foundation System – General Considerations
Based on an initial cursory observation of the existing 1 to 2-story building exterior constructed in
approximately 1936, there are no noticeable structural issues. At this time it is our understanding the
type of foundation system for the existing building is unknown. We also understand that the
proposed 4-story building to be built immediately to the east will be kept completely separate for the
existing building (i.e. not tied/doweled together) to reduce the effects on the existing building,
although second and third story apartments will have walkout balconies that step onto the existing
buildings roof.
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Notwithstanding the performance of the existing structure, placing foundation loads on subsoils
outside of the existing building footprint will result in some settlement of those footings as the loads
are applied. Since the existing foundations have experienced loading over a period of approximately
80 years we do not expect additional settlement will occur in those foundations caused by minor
additional loads being placed on those footings. However, new footing loads placed in close
proximity to the existing foundations, if the existing foundation system is conventional shallow
spread footings, can result in increased stresses in the subgrade soils below existing foundations and
result in some small settlements of existing footings from the adjacent loads in close proximity.
The site appears suitable for the proposed construction based on the results of our field exploration and
our understanding of the proposed development. The following foundation systems were evaluated for
use on the site for the proposed building.
Due to the necessity to overexcavate and replace the existing previously placed near surface fill
subsoils to accommodate an approved bearing stratum for portions of the proposed building
foundations as well as the potential for applying additional loads to the existing building
foundation, consideration could be given to supporting the proposed buildings on a grade beam
and straight shaft drilled pier/caisson foundation system extending into the underlying bedrock
formation. Consideration should also be given to the use of a structural floor slab in
conjunction with a drilled pier/caisson foundation system; however, an overexcavation and
replacement with an imported structural fill material and/or on-site engineered fill material to
allow for a slab-on-grade could also be considered.
Conventional type spread footings bearing on approved in-situ native subsoils and/or on a zone
of approved engineered fill material with the understanding of greater possible movement and
potential movement of the existing building foundation system.
Drilled Piers/Caissons Foundations
Based on the subgrade conditions observed in the test borings and on the anticipated foundation loads,
as well as to minimize impact to the existing building, we recommend as a primary alternative of
supporting the proposed building on a grade beam and straight shaft drilled pier/caisson foundation
system extending into the underlying bedrock formation. Particular attention will be required in the
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construction of drilled piers due to the presence of silty to poorly graded sand and gravel, groundwater,
and the potential for well cemented sandstone lenses.
For axial compression loads, the drilled piers could be designed using a maximum end bearing pressure
of 40,000 pounds per square foot (psf), along with a skin-friction of 4,000 psf for the portion of the pier
extended into the underlying firm and/or harder bedrock formation. Straight shaft piers should be
drilled a minimum of 10-feet into competent or harder bedrock, with minimum shaft lengths of 25-feet
are recommended, whichever results in the longer shaft length. With bedrock observed at depths of
approximately 16 to 17 feet below existing site grades, pier lengths of 26 feet and greater should be
expected. Lower values may be appropriate for pier “groupings” depending on the pier diameters and
spacing. Pile groups should be evaluated individually.
To satisfy forces in the horizontal direction, piers may be designed for lateral loads using a modulus
of 33 tons per cubic foot (tcf) for the portion of the pier in native cohesive soils, 50 tcf for
engineered fill, and 267 tcf in bedrock for a pier diameter of 18 inches. The coefficient of subgrade
reaction for varying pier diameters are as follow and generally conform to the formula of, (kh =
50/D, 75/D, or 400/D respectively for cohesive soils, non-cohesive soils, and bedrock, in which
D=pier diameter):
TABLE III - Coefficient of Subgrade Reaction for Varying Pier Diameters
Pier Diameter (inches)
Coefficient of Subgrade Reaction (tons/ft3)
Cohesive Soils
Engineered Fill or
Granular Soils
Bedrock
18 33 50 267
24 25 38 200
30 20 30 160
36 17 25 133
When the lateral capacity of drilled piers is evaluated by the L-Pile computer programs, we recommend
that internally generated load-deformation (P-Y) curves be used. To satisfy forces in the horizontal
direction using L-piles computer programs, shafts/piers may be designed using the following lateral
load criteria:
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TABLE IV – L-Pile Design Parameters
Parameters On-Site Soils –
Cohesive Soils
Native Granular Soils or
Structural Fill Bedrock
Unit Weight of Soil (pcf) 115(1)
130(1)
125(1)
Average Undrained Shear Strength (psf) 2,000 0 5,000
Angle of Internal Friction (degrees) 20 35 25
Coefficient of Subgrade Reaction, ks & kc (pci)
500-static
200 – cyclic
800-static
500 – cyclic
2,000 – static
800 - cyclic
Strain, 50 (%)
(2) 0.007 --- 0.004
*Notes: 1) Reduce by 64 PCF below the water table
2) The 50 values represent the strain corresponding to 50 percent of the maximum principal stress
difference. The modulus of subgrade reaction for static (ks) and cyclical (kc) are used by the L-Pile
computer programs to generate the slope of the initial portion of the “p-y curves.”
All piers should be reinforced full-depth for the applied axial, lateral and uplift stresses imposed.
Minimum reinforcement of at least one percent of the cross-sectional area of each pier should be
specified. For this project, use of a minimum pier diameter of 18 inches is recommended.
For axial loading, a minimum horizontal spacing between piers of at least 3 diameters should be
maintained, and adjacent piers should bear at or near the same elevation. The capacity of individual
piers must be reduced when considering the effects of group action. Capacity reduction is a function of
pier spacing and the number of piers within a group. At one diameter, (essentially piers in contact with
each other), the skin friction load reduction factor for each pier should be reduced by 50 percent. End
bearing values would not be reduced provided the end-bearing stratum is essentially the same.
Piers in-line with the direction of lateral loads should have a minimum spacing of at least 6 pier
diameters, from the center to center, based upon the larger diameter pier. Due to the complexity of
the project, if a closer pier spacing configuration is required, the modulus of subgrade reaction for
the initial and trailing piers should be reduced. The effective modulus of subgrade reaction for the
first pier, at a spacing of 3 pier diameters, should be calculated by multiplying the respective Kh, Ks,
and Kc values by 0.6, while the trailing piers at a spacing of 3-pier diameters, the effective subgrade
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modulus would be calculated by multiplying the respective Kh, Ks, and Kc values by 0.40. Linear
interpolation can be utilized for spacing between the 3 to 6 diameters as presented herein.
Reductions to the modulus of subgrade reaction can be accomplished in L-Pile by inputting the
appropriate modification factors for p-y curves. Reducing the modulus of subgrade reaction in
trailing piers will result in greater computed deflections on these piers. In practice, the grade beam
can force deflections of all piers to be essentially equal. Load-deflection graphs can be generated for
each pier using the appropriate p-y multiplier values. The sum of the pier lateral load resistance at
selected deflections can be used to develop a total lateral load versus deflection graph for the system
of piers.
For lateral loads perpendicular to the line of piers, a minimum spacing of 3 diameters can be used
with no bearing capacity reduction. At one diameter, (essentially piers in contact with each other),
the piers can be analyzed as one element. Interpolation can be used for intermediate pier spacing
conditions.
Drilling caissons to design depth should be possible with conventional heavy-duty single flight power
augers equipped with rock teeth on the majority of the site. Due to the presence of silty to poorly
graded sand and gravel and groundwater at approximate depths of 16 to 19 feet below site grades,
maintaining open shafts for the caissons may be difficult without stabilizing measures. We expect
temporary casing will be required to adequately/properly drill and clean piers prior to concrete
placement. In addition, areas of well-cemented sandstone bedrock lenses may be encountered
throughout the site at various depths where specialized drilling equipment and/or rock excavating
equipment may be required. Excavation penetrating the well-cemented sandstone bedrock may require
the use of specialized heavy-duty equipment, together with rock augers and/or core barrels.
Consideration should be given to obtaining a unit price for difficult caisson excavation in the contract
documents for the project.
Groundwater should be removed from each pier hole prior to concrete placement. Pier concrete should
be placed immediately after completion of drilling and cleaning. A maximum 3-inch depth of
groundwater is acceptable in each pier prior to concrete placement. If pier concrete cannot be placed in
dry conditions, a tremie should be used for concrete placement. Due to potential sloughing and
raveling, foundation concrete quantities may exceed calculated geometric volumes. Pier concrete with
slump in the range of 6 to 8 inches is recommended. Casing used for pier construction should be
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withdrawn in a slow continuous manner maintaining a sufficient head of concrete to prevent infiltration
of soil/water or the creation of voids in pier concrete.
Foundation excavations should be observed by the geotechnical engineer. A representative of the
geotechnical engineer should inspect the bearing surface and pier configuration. If the soil conditions
encountered differ from those presented in this report, supplemental recommendations may be
required.
We estimate the long-term settlement of drilled pier foundations designed and constructed as outlined
above would be less than 1-inch.
Footing Foundations
A secondary alternative for supporting the proposed building, consideration could be given for the use
of conventional spread foundations bearing on approved on-site native subgrade soils or a zone of
approved/placed and compacted engineered fill. Close evaluation for the use of spread footings would
be required to minimize impact to the adjacent building’s foundation system. For design of footing
foundations supported on properly placed and compacted engineered fill as outlined in the section “Site
Preparation” or on approved native subgrade soils, we recommend using a maximum net allowable
total load soil bearing pressure of 2,000 psf. A minimum dead load pressure would not be required.
The net bearing pressure refers to the pressure at foundation bearing level in excess of the minimum
surrounding overburden pressure. Total load would include full dead and live loads.
Exterior foundations and foundations in unheated areas should be located at least 30 inches below
adjacent exterior grades to provide frost protection. Formed continuous footings should have a
minimum width of 16 inches and isolated column foundations should have a minimum width of 30
inches.
Care should be taken to thoroughly evaluate anticipated bearing materials at the time of construction.
All footings for the structures should bear on uniform/similar materials to reduce the potential for
differential movement between soil types. We estimate the long term settlement of footings designed
and constructed as outlined would be less than 1-inch.
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Seismic
The site soil conditions generally consist of loose to medium dense clayey sand with underlying
dense to very dense silty to poorly graded sand and gravel materials with underlying
siltstone/sandstone bedrock at approximate depths of 16 to 17 feet below existing site grades. For
those site conditions, the 2012 International Building Codes indicates a Seismic Site Classification
of C.
Floor Slabs and Flatwork Subgrades
Subgrades for floor slabs and flatwork should be prepared as outlined in the “Site Preparation”
section of this report. We estimate the long-term movement of floor slabs with properly prepared
subgrade subsoils as outlined above would be about one-inch or less assuming reasonable moisture
accumulation in the subgrade materials. Excessive moisture accumulation from any source can
result in additional movements.
For structural design of concrete slabs-on-grade, a modulus of subgrade reaction of 100 pounds per
cubic inch (pci) may be used for floors supported on a zone of reconditioned engineered fill.
Care should be taken after preparation of the subgrades to avoid disturbing the subgrade materials.
Materials which are loosened or materials which become dry and desiccated or wet and softened
should be removed and replaced prior to placement of the overlying floor slabs. Care should be
taken to maintain proper moisture contents in the subgrade soils prior to placement of any overlying
improvements. An underslab gravel layer or thin leveling course could be used underneath the
concrete floor slabs to provide a capillary break mechanism, a load distribution layer, and as a
leveling course for the concrete placement.
Additional floor slab design and construction recommendations are as follows:
Positive separations and/or isolation joints should be provided between slabs and all
foundations, columns or utility lines to allow independent movement.
Control joints should be provided in slabs to control the location and extent of
cracking.
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Interior trench backfill placed beneath slabs should be compacted in a similar manner
as previously described for on-site or imported structural fill material.
Floor slabs should not be constructed on frozen subgrade.
Other design and construction considerations, as outlined in the ACI Design Manual,
Section 302.1R are recommended.
Soil Corrosivity
The water soluble sulfate (SO4) testing of the on-site overburden and underlying bedrock material
taken during our subsurface exploration is 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 subsoils.
TABLE V - Water Soluble Sulfate Test Results
Sample Location Description
Soluble Sulfate Content
(mg/kg)
Soluble Sulfate Content
(%)
B-1, S-2 at 4’ Clayey Sand (SC) 210 0.02
B-2, S-7 at 29’ Siltstone/Sandstone 280 0.03
B-3, S-4 at 14’ Silty Sand and Gravel 240 0.02
Based on the results as presented in the table above, ACI 318, Section 4.2 indicates the site
overburden soils have a low risk of sulfate attack on Portland cement concrete. Therefore Class 0
and/or Type I/II cement could be used for concrete on and below site grade within the overburden
soils or underlying 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
Cementatious 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
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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. Care should be taken in
planning of landscaping, (if required), adjacent to the buildings to avoid features which would pond
water adjacent to the foundations or stemwalls. 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. Irrigation systems should not be placed within 5 feet of the perimeter
of the building. Spray heads should be designed not to spray water on or immediately adjacent to
the structure. Roof drains should be designed to discharge at least 5 feet away from the structure.
Excavations into the on-site clayey sand can be expected to stand on relatively steep, temporary
slopes during construction. Deeper excavations into the underlying silty to poorly graded sand and
gravel have the potential for caving/sloughing side walls. 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.
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
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 of Poudre Garage, LLC c/o Diehl Management
for specific application to the project discussed and has been prepared in accordance with generally
Earth Engineering Consultants, LLC
EEC Project No. 1162021
March 30, 2016
Page 15
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
1
2
B-2
B-1
B-3
Boring Location Diagram
Poudre Garage - 148 Remington St
Fort Collins, Colorado
EEC Project #: 1162021 Date: March 2016
Approximate Boring
Locations
1
EARTH ENGINEERING CONSULTANTS, LLC
Legend
Site Photos
(Photos taken in approximate
location, in direction of arrow)
POUDRE GARAGE – 148 REMINGTON STREET
FORT COLLINS, COLORADO
EEC PROJECT NO. 1162021
MARCH 2016
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
GRAVEL - 6" _ _
CLAYEY SAND - FILL 1
brown / black _ _
with gravel 2
_ _ % @ 150 psf
CLAYEY SAND (SC) CS 3 50 9000+ 15.3 117.4 29 14 43.1 <150 psf None
brown / tan / red _ _
dense to medium dense 4
with calcareous deposits _ _
SS 5 18 8000 16.7
_ _
6
_ _
7
_ _
8
_ _
9
_ _
SILTY SAND & GRAVEL (SM/GM) CS 10 50 -- 2.0 128.4 7.0
brown / tan _ _
dense to very dense 11
with cobbles _ _
no recovery 12
_ _
13
_ _
14
_ _
SS 15 50/4" -- 2.2
_ _
16
_ _
SILTSTONE / SANDSTONE 17
grey _ _
cemented to well cemented 18
_ _
19
_ _
SS 20 50/2" -- 6.0
_ _
21
_ _
22
_ _
23
_ _
24
_ _
SS 25 50/4" -- 13.8
Continued on Sheet 2 of 2 _ _
Earth Engineering Consultants, LLC
A-LIMITS SWELL
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
Continued from Sheet 1 of 2 26
_ _
SILTSTONE / SANDSTONE 27
grey / brown _ _
cemented to well cemented 28
_ _
29
_ _
SS 30 50/3" 9000+ 13.2
_ _
BOTTOM OF BORING DEPTH 30.5' 31
_ _
32
_ _
33
_ _
34
_ _
35
_ _
36
_ _
37
_ _
38
_ _
39
_ _
40
_ _
41
_ _
42
_ _
43
_ _
44
_ _
45
_ _
46
_ _
47
_ _
48
_ _
49
_ _
50
_ _
Earth Engineering Consultants, LLC
A-LIMITS SWELL
N/A
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
GRAVEL - 6" _ _
1
CLAYEY SAND - FILL _ _
brown / red / black 2
with gravel _ _
SS 3 6 5000 13.5
_ _
4
_ _
CS 5 9 5000 12.8 115.1 27 10 41.3 <500 psf None
CLAYEY SAND (SC) _ _
red / brown 6
loose _ _
7
_ _
8
_ _
SILTY SAND & GRAVEL (SM/GM) 9
brown / tan _ _
dense to very dense SS 10 50/5" -- 4.4
with cobbles _ _
11
_ _
12
_ _
13
_ _
14
_ _
SS 15 52 -- 3.4 12.0
_ _
16
_ _
17
SILTSTONE / SANDSTONE _ _
brown / grey / rust 18
cemented to well cemented _ _
19
_ _
SS 20 50/3" -- 13.8
_ _
21
_ _
22
_ _
23
_ _
24
*classifies as SILTY SAND (SM) _ _ % @ 1000 psf
CS 25 50/5" 9000+ 12.9 113.3 NL NP 23.5 1200 psf 0.1%
Continued on Sheet 2 of 2 _ _
Earth Engineering Consultants, LLC
A-LIMITS SWELL
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
Continued from Sheet 1 of 2 26
_ _
SILTSTONE / SANDSTONE 27
brown / grey / rust _ _
cemented to well cemented 28
_ _
29
_ _
grey SS 30 50/4" -- 15.2
_ _
BOTTOM OF BORING DEPTH 30.5' 31
_ _
32
_ _
33
_ _
34
_ _
35
_ _
36
_ _
37
_ _
38
_ _
39
_ _
40
_ _
41
_ _
42
_ _
43
_ _
44
_ _
45
_ _
46
_ _
47
_ _
48
_ _
49
_ _
50
_ _
Earth Engineering Consultants, LLC
A-LIMITS SWELL
N/A
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
GRAVEL - 6" _ _
1
CLAYEY GRAVEL - FILL _ _
brown / black 2
loose _ _
with gravel CS 3 6 -- 6.7
no recovery; auger cuttings _ _
4
CLAYEY SAND (SC) _ _
brown / red / tan CS 5 9 8000 11.3 118.2 27 14 45.3 <500 psf None
loose _ _
6
_ _
7
_ _
8
_ _
9
SILTY SAND & GRAVEL (SM/GM) _ _
brown / tan SS 10 32 -- 3.1
dense to very dense _ _
with cobbles 11
_ _
12
_ _
13
_ _
14
_ _
SS 15 50/7" -- 1.8 12.5
_ _
16
_ _
17
_ _
SILTSTONE / SANDSTONE 18
brown / grey / rust _ _
cemented to well cemented 19
_ _
SS 20 50/3" -- 12.5
_ _
21
_ _
22
_ _
23
_ _
24
grey _ _
SS 25 50/3" 4000 14.1 108.1
Continued on Sheet 2 of 2 _ _
Earth Engineering Consultants, LLC
A-LIMITS SWELL
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
Continued from Sheet 1 of 2 26
_ _
SILTSTONE / SANDSTONE 27
grey _ _
cemented to well cemented 28
_ _
29
_ _
brown / grey / rust SS 30 50/4" -- 13.7
_ _
BOTTOM OF BORING DEPTH 30.5' 31
_ _
32
_ _
33
_ _
34
_ _
35
_ _
36
_ _
37
_ _
38
_ _
39
_ _
40
_ _
41
_ _
42
_ _
43
_ _
44
_ _
45
_ _
46
_ _
47
_ _
48
_ _
49
_ _
50
_ _
Earth Engineering Consultants, LLC
A-LIMITS SWELL
N/A
Project:
Location:
Project #:
Date:
Poudre Garage - 148 Remington Street
Fort Collins, Colorado
1162021
March 2016
Beginning Moisture: 15.3% Dry Density: 117.4 pcf Ending Moisture: 13.2%
Swell Pressure: <150 psf % Swell @ 150: None
Sample Location: Boring 1, Sample 1, Depth 2'
Liquid Limit: 29 Plasticity Index: 14 % Passing #200: 43.1%
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown, Tan, Red Clayey Sand (SC)
-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:
Poudre Garage - 148 Remington Street
Fort Collins, Colorado
1162021
March 2016
Beginning Moisture: 12.8% Dry Density: 117.4 pcf Ending Moisture: 13.0%
Swell Pressure: <500 psf % Swell @ 500: None
Sample Location: Boring 2, Sample 2, Depth 4'
Liquid Limit: 27 Plasticity Index: 10 % Passing #200: 41.3%
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Red, Brown Clayey Sand (SC)
-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:
Poudre Garage - 148 Remington Street
Fort Collins, Colorado
1162021
March 2016
Beginning Moisture: 12.9% Dry Density: 113.3 pcf Ending Moisture: 22.3%
Swell Pressure: 1400 psf % Swell @ 1000: 0.1%
Sample Location: Boring 2, Sample 6, Depth 24'
Liquid Limit: NL Plasticity Index: NP % Passing #200: 23.5%
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown, Grey, 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:
Poudre Garage - 148 Remington Street
Fort Collins, Colorado
1162021
March 2016
Beginning Moisture: 11.3% Dry Density: 118.2 pcf Ending Moisture: 13.9%
Swell Pressure: <500 psf % Swell @ 500: None
Sample Location: Boring 3, Sample 2, Depth 4'
Liquid Limit: 27 Plasticity Index: 14 % Passing #200: 45.3%
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown, Red, Tan Clayey Sand (SC)
-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
2 1/2" (63 mm)
2" (50 mm)
1 1/2" (37.5 mm)
1" (25 mm)
3/4" (19 mm)
1/2" (12.5 mm)
3/8" (9.5 mm)
No. 4 (4.75 mm)
No. 8 (2.36 mm)
No. 10 (2 mm)
No. 16 (1.18 mm)
No. 30 (0.6 mm)
No. 40 (0.425 mm)
No. 50 (0.3 mm)
No. 100 (0.15 mm)
No. 200 (0.075 mm)
Project: Poudre Garage - 148 Remington Street
Location: Fort Collins, Colorado
Project No: 1162021
Sample ID: B-1, S-3, 9'
Sample Desc.: Silty/Poorly Graded Sand & Gravel (SM/GM-SP/GP)
Date: March 2016
23
20
17
11
7.0
59
48
39
37
31
100
85
81
73
64
100
EARTH ENGINEERING CONSULTANTS, LLC
SUMMARY OF LABORATORY TEST RESULTS
Sieve Analysis (AASHTO T 11 & T 27 / ASTM C 117 & C 136)
Sieve Size Percent Passing
Gravel
Coarse Fine
Sand
Coarse Medium Fine
EARTH ENGINEERING CONSULTANTS, LLC
Summary of Washed Sieve Analysis Tests (ASTM C117 & C136)
Date:
Poudre Garage - 148 Remington Street
Fort Collins, Colorado
1162021
B-1, S-3, 9'
Silty/Poorly Graded Sand & Gravel (SM/GM-SP/GP)
March 2016
Project:
Location:
Project No:
Sample ID:
Sample Desc.:
Cobble Silt or Clay
6"
5"
4"
3"
2.5"
2"
1.5"
1"
3/4"
1/2"
3/8"
No. 4
No. 8
No. 10
No. 16
No. 30
No. 40
No. 50
No. 100
No. 200
0
10
20
30
40
50
60
70
80
90
100
1000 100 10 1 0.1 0.01
Fines by Weight (%)
Grain Size (mm)
Standard Sieve Size
2 1/2" (63 mm)
2" (50 mm)
1 1/2" (37.5 mm)
1" (25 mm)
3/4" (19 mm)
1/2" (12.5 mm)
3/8" (9.5 mm)
No. 4 (4.75 mm)
No. 8 (2.36 mm)
No. 10 (2 mm)
No. 16 (1.18 mm)
No. 30 (0.6 mm)
No. 40 (0.425 mm)
No. 50 (0.3 mm)
No. 100 (0.15 mm)
No. 200 (0.075 mm)
Project: Poudre Garage - 148 Remington Street
Location: Fort Collins, Colorado
Project No: 1162021
Sample ID: B-2, S-4, 14'
Sample Desc.: Silty/Poorly Graded Sand & Gravel (SM/GM-SP/GP)
Date: March 2016
36
30
25
17
12.0
76
68
59
57
48
100
100
96
86
80
100
EARTH ENGINEERING CONSULTANTS, LLC
SUMMARY OF LABORATORY TEST RESULTS
Sieve Analysis (AASHTO T 11 & T 27 / ASTM C 117 & C 136)
Sieve Size Percent Passing
Gravel
Coarse Fine
Sand
Coarse Medium Fine
EARTH ENGINEERING CONSULTANTS, LLC
Summary of Washed Sieve Analysis Tests (ASTM C117 & C136)
Date:
Poudre Garage - 148 Remington Street
Fort Collins, Colorado
1162021
B-2, S-4, 14'
Silty/Poorly Graded Sand & Gravel (SM/GM-SP/GP)
March 2016
Project:
Location:
Project No:
Sample ID:
Sample Desc.:
Cobble Silt or Clay
6"
5"
4"
3"
2.5"
2"
1.5"
1"
3/4"
1/2"
3/8"
No. 4
No. 8
No. 10
No. 16
No. 30
No. 40
No. 50
No. 100
No. 200
0
10
20
30
40
50
60
70
80
90
100
1000 100 10 1 0.1 0.01
Fines by Weight (%)
Grain Size (mm)
Standard Sieve Size
2 1/2" (63 mm)
2" (50 mm)
1 1/2" (37.5 mm)
1" (25 mm)
3/4" (19 mm)
1/2" (12.5 mm)
3/8" (9.5 mm)
No. 4 (4.75 mm)
No. 8 (2.36 mm)
No. 10 (2 mm)
No. 16 (1.18 mm)
No. 30 (0.6 mm)
No. 40 (0.425 mm)
No. 50 (0.3 mm)
No. 100 (0.15 mm)
No. 200 (0.075 mm)
Project: Poudre Garage - 148 Remington Street
Location: Fort Collins, Colorado
Project No: 1162021
Sample ID: B-3, S-3, 9'
Sample Desc.: Silty/Poorly Graded Sand & Gravel (SM/GM-SP/GP)
Date: March 2016
37
33
30
20
12.5
73
64
54
52
45
100
100
92
84
79
100
EARTH ENGINEERING CONSULTANTS, LLC
SUMMARY OF LABORATORY TEST RESULTS
Sieve Analysis (AASHTO T 11 & T 27 / ASTM C 117 & C 136)
Sieve Size Percent Passing
Gravel
Coarse Fine
Sand
Coarse Medium Fine
EARTH ENGINEERING CONSULTANTS, LLC
Summary of Washed Sieve Analysis Tests (ASTM C117 & C136)
Date:
Poudre Garage - 148 Remington Street
Fort Collins, Colorado
1162021
B-3, S-3, 9'
Silty/Poorly Graded Sand & Gravel (SM/GM-SP/GP)
March 2016
Project:
Location:
Project No:
Sample ID:
Sample Desc.:
Cobble Silt or Clay
6"
5"
4"
3"
2.5"
2"
1.5"
1"
3/4"
1/2"
3/8"
No. 4
No. 8
No. 10
No. 16
No. 30
No. 40
No. 50
No. 100
No. 200
0
10
20
30
40
50
60
70
80
90
100
1000 100 10 1 0.1 0.01
Fines by Weight (%)
Grain Size (mm)
Standard Sieve Size
3/16/2016 AFTER DRILLING None
SURFACE ELEV 24 HOUR N/A
FINISH DATE
SHEET 2 OF 2 WATER DEPTH
START DATE 3/16/2016 WHILE DRILLING None
POUDRE GARAGE - 148 REMINGTON STREET
FORT COLLINS, COLORADO
PROJECT NO: 1162021 LOG OF BORING B-3 MARCH 2016
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 3/16/2016 AFTER DRILLING None
SHEET 1 OF 2 WATER DEPTH
START DATE 3/16/2016 WHILE DRILLING None
POUDRE GARAGE - 148 REMINGTON STREET
FORT COLLINS, COLORADO
PROJECT NO: 1162021 LOG OF BORING B-3 MARCH 2016
3/16/2016 AFTER DRILLING 16.2'
SURFACE ELEV 24 HOUR N/A
FINISH DATE
SHEET 2 OF 2 WATER DEPTH
START DATE 3/16/2016 WHILE DRILLING None
POUDRE GARAGE - 148 REMINGTON STREET
FORT COLLINS, COLORADO
PROJECT NO: 1162021 LOG OF BORING B-2 MARCH 2016
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 3/16/2016 AFTER DRILLING 16.2'
SHEET 1 OF 2 WATER DEPTH
START DATE 3/16/2016 WHILE DRILLING None
POUDRE GARAGE - 148 REMINGTON STREET
FORT COLLINS, COLORADO
PROJECT NO: 1162021 LOG OF BORING B-2 MARCH 2016
3/16/2016 AFTER DRILLING 19.1'
SURFACE ELEV 24 HOUR N/A
FINISH DATE
SHEET 2 OF 2 WATER DEPTH
START DATE 3/16/2016 WHILE DRILLING None
POUDRE GARAGE - 148 REMINGTON STREET
FORT COLLINS, COLORADO
PROJECT NO: 1162021 LOG OF BORING B-1 MARCH 2016
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 3/16/2016 AFTER DRILLING 19.1'
SHEET 1 OF 2 WATER DEPTH
START DATE 3/16/2016 WHILE DRILLING None
POUDRE GARAGE - 148 REMINGTON STREET
FORT COLLINS, COLORADO
PROJECT NO: 1162021 LOG OF BORING B-1 MARCH 2016
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