HomeMy WebLinkAboutGEICO OFFICE BUILDING - PDP - PDP130039 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTGEOTECHNICAL SUBSURFACE EXPLORATION REPORT
GEICO INSURANCE OFFICE BUILDING
2024 EAST HARMONY ROAD
FORT COLLINS, COLORADO
EEC PROJECT NO. 1132073
Prepared for:
Geico Insurance
115 East Harmony Road, #110
Fort Collins, Colorado 80525
Attn: Mr. Steve Allen (SAllen@geico.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
EARTH ENGINEERING
CONSULTANTS, LLC
October 14, 2013
Geico Insurance
115 East Harmony Road, #110
Fort Collins, Colorado 80525
Attn: Mr. Steve Allen (SAllen@geico.com)
Re: Geotechnical Subsurface Exploration Report
Geico Insurance Office Building
2024 East Harmony Road
Fort Collins, Colorado
EEC Project No. 1132073
Mr. Allen:
Enclosed, herewith, are the results of the geotechnical subsurface exploration completed by
Earth Engineering Consultants, LLC (EEC) for the referenced project. For this
exploration, four (4) soil borings were drilled on September 20, 2013 within the proposed
development area to obtain information on the existing subsurface conditions. The borings
were extended to approximate depths of 20 feet below present site grades within the
proposed building footprint and approximately 10 feet below existing site grades within
the proposed site pavement areas. It should be noted this site at one time was a former gas
station. This geotechnical engineering subsurface exploration study/report does not address
any potential environmental related issues regarding the site’s former usage. An
environmental site assessment is beyond the scope of our services. This exploration was
completed in general accordance with our proposal dated September 3, 2013.
In summary, the subsurface soils encountered beneath the surficial vegetation/topsoil
materials generally consisted of sandy lean clay. Groundwater was encountered at depths
of approximately of 15 to 17 feet below existing site grades.
Based on the subsurface conditions encountered at the site and the anticipated maximum
loading conditions, we believe the proposed structure could be supported on conventional
spread footing foundations supported on natural, stiff sandy lean clay and/or on a zone of
placed and approved fill material. The building floor slabs/pavements/flatwork could also
be supported on the site sandy lean clay soils or approved fill although care will be needed
to mitigate areas of higher swelling dry/dense subgrades. Geotechnical recommendations
concerning design and construction of the proposed building foundations and site
floors/pavements are detailed in the attached report.
GEOTECHNICAL SUBSURFACE EXPLORATION REPORT
GEICO INSURANCE OFFICE BUILDING
2024 EAST HARMONY ROAD
FORT COLLINS, COLORADO
EEC PROJECT NO. 1132073
October 11, 2013
INTRODUCTION
The geotechnical subsurface exploration for the proposed two-story office building to be located
at 2024 East Harmony Road in Fort Collins, Colorado, has been completed. For this exploration,
two (2) soil borings were advanced to depths of approximately 20 feet within the proposed
building area to obtain information on existing subsurface conditions. Two (2) other borings
were advanced to depths of approximately 10 feet below existing ground surface in proposed
drive and parking areas west of the building location. This exploration was completed in general
accordance with our proposal for this project dated September 3, 2013.
We understand the new office building will be two (2) story, slab-on-grade with a plan area of
approximately 2,500 square feet. The new structure will be wood frame construction with light
foundation and floor loads. The site drive and parking areas are expected to carry low volumes of
light vehicular traffic. We anticipate small cuts and fills will be necessary to develop final site
grades. Prior site structures have been demolished and removed from the site.
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 and pavements.
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
Earth Engineering Consultants, LLC
EEC Project No. 1132073
October 11, 2013
Page 2
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 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. 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 samples. Swell/consolidation tests were
completed on selected samples to evaluate the potential for the subgrade materials to change
volume with variation in moisture content and load. 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
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.
SITE AND SUBSURFACE CONDITIONS
The development parcel was relatively level at the time of our field exploration; however, areas
of removal of the prior structures were evident. Some site grading associated with the building
removal was also evident.
In the areas of the completed testing borings, the ground surface was generally covered with
sparse vegetation and/or topsoil. The surficial pavement/topsoil materials were underlain by
sandy lean clay. A portion of the near surface lean clay appeared to be reworked native soils or
Earth Engineering Consultants, LLC
EEC Project No. 1132073
October 11, 2013
Page 3
placed fill materials. The sandy lean clay was generally stiff to very stiff with low to moderate
plasticity and generally low swell potential at current moisture and density. Higher swell was
measured in one sample of dry, dense lean clay from pavement area boring B-4. The lean clay
soils extended to the bottom of the borings at depths of approximately 10 or 20 feet below current
site grades.
The stratification boundaries indicated on the boring logs represent the approximate locations of
changes in soil 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 observed in the test
borings in the building area at approximate depths of 15 to 17 feet below ground surface. The
bore holes were backfilled upon completion of our drilling operations with auger cuttings;
additional water level 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, overlying lower permeability bedrock and/or within
permeable seams in the bedrock.
ANALYSIS AND RECOMMENDATIONS
Swell/Consolidation Test Results
Swell-consolidation testing was performed on relatively undisturbed specimens obtained from the
California barrel sampler. Swell-consolidation testing was performed to evaluate the swell
potential, collapse potential, and consolidation response of the relatively undisturbed specimens.
The swell-consolidation testing is used, in part, to predict heave and/or settlement of the site
improvements.
Earth Engineering Consultants, LLC
EEC Project No. 1132073
October 11, 2013
Page 4
For this exploration a total of four (4) specimens were tested for swell/consolidation. The
laboratory specimens subjected to swell-consolidation testing were inundated with water under a
surcharge pressure of 150 or 500 psf. The surcharge pressure was selected based on the
estimated future vertical pressure on the soil as a result of the planned site improvements. The
results of the swell-consolidation testing are shown on the attached laboratory swell-
consolidation testing summary sheets.
Results of the laboratory testing indicate generally low swell potential in the lean clay soils with
swells of 0.0% to + 0.1% under a 500 psf dead load. In the pavement area, one (1) small sample
showed expansion of 8.3% under a dead load of 150 psf. That sample was relatively dry and
dense.
Site Preparation
Prior buildings on the site have been recently demolished with apparent surficial grading
completed in the prior building areas. Care should be taken to see that all prior building
foundations, floor slabs, and any previously placed backfill or recently placed uncontrolled
backfill associated with the prior structures be completely removed from the improvement areas.
Within the development area, any existing trees and their entire root system should be removed.
Any dry and desiccated soils surrounding the root systems should also be removed. Any existing
vegetation and topsoil should be removed from improvement and/or fill areas on the site.
Any observed fill material should be removed from the development area. Care should be taken
to thoroughly evaluate the site for any addition fill and/or backfill placed during any prior
building construction and/or demolition on the site. If encountered, those fill materials should be
removed or evaluated by a geotechnical engineer.
Care should be taken to further evaluate the near surface clay subgrades to identify areas of
dry/dense cohesive soils with higher swell potential. To help reduce the potential swell of the
subgrades in the building/parking and pavement areas, we recommend all in-situ dry/dense
cohesive soils be removed to a depth of 2 feet below proposed top-of-subgrade elevation or 2 feet
below current surface elevation, whichever is deeper. Removal and replacement of a zone of the
in-situ moderately expansive subgrade soils will reduce the potential for post-construction
Earth Engineering Consultants, LLC
EEC Project No. 1132073
October 11, 2013
Page 5
heaving. However, the potential for movement will not be eliminated with the relatively shallow
overexcavation depths outlined. Greater overexcavation depth would further reduce the post-
construction movement potential; use of structural floor with a void space between the subgrade
and the floor would be required to eliminate movement potential.
After stripping, completing all cuts, and prior to placement of any fill or site improvements, we
recommend the exposed soils be scarified to a minimum depth of 9 inches, adjusted in 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. The moisture content should be
adjusted to within ±2% for cohesive soils and ±3% for essentially granular soils.
Fill soils required for developing the site grades and backfilling of any removed structures, trees
or prior fills and overexcavation required should consist of approved, low-volume-change
materials, which are free from organic matter and debris. Fill soils should be graded similar to
the site sandy lean clays. However, if importing materials is necessary, imported fill materials
should consist of essentially granular material such an aggregate base similar to a CDOT Class 5,
Class 6 or Class 7.
We recommend fill soils be placed in loose lifts not to exceed 9 inches thick and adjusted in
moisture content and compacted to at least 95% of the materials maximum dry density as
determined in accordance with ASTM Specification D698, the standard Proctor procedure. The
moisture content of the fill soils should be adjusted to within ±2% of optimum moisture content
for cohesive soils and ±3% of optimum moisture for essentially granular materials.
Footing Foundations
It is our opinion the proposed building could be supported on conventional spread footing
foundations bearing on the natural stiff sandy lean clays or on newly placed and compacted fill
placed as outlined in the section titled “Site Preparation.”
For design of footing foundations bearing on natural stiff sandy lean clay or on a zone of
approved fill material, we recommend using a net allowable total load soil bearing pressure not to
exceed 1,500 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 for the structure. Close evaluation of the foundation bearing strata materials will be
necessary during the construction phase.
Earth Engineering Consultants, LLC
EEC Project No. 1132073
October 11, 2013
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Exterior foundations and foundations in unheated areas should be located a minimum of 30
inches below adjacent exterior grade to provide frost protection. We recommend formed
continuous footings have a minimum width of 16 inches and isolated column foundations have a
minimum width of 30 inches. Trenched and/or grade beam foundations should not be used in the
near surface soils.
We estimate the long term settlement of footing foundations designed and constructed as
recommended as above would be less than 1 inch.
Seismic
The site soil conditions consist of greater than 20 feet of overburden lean clay soils. For those
site conditions, the 2009 International Building Code indicates a Seismic Site Classification of D.
Floor/Pavement/Flatwork Subgrades
Based on the subgrades observed at the site, we anticipate the near surface
floors/pavements/flatwork would be supported on a zone of at least 2 feet of newly placed and
compacted fill soils or on in-place low volume dense natural sandy lean clay soils.
The pavement/flatwork areas should be prepared as recommended in the section titled Site
Preparation. We recommend the exposed subgrades be scarified to at least 9 inches in depth,
adjusted in moisture content and compacted to at least 95% of standard Proctor (ASTM D698)
maximum dry density. The moisture content of the scarified soils should be adjusted to within
±2% of optimum moisture content.
Fill materials to develop the subgrade elevations should consist of approved, low volume change
material, free from organic matter and debris. In our opinion the native soils could be used
provided the required moisture contents are maintained in subgrades prior to placement of
overlying improvements. Fill materials should be moisture conditioned and compacted as
outlined for the scarified soils.
Care should be taken after preparation of the subgrades to avoid disturbing the subgrade
materials. Materials which are loosened or disturbed by the construction activities or materials
which become dry and desiccated or wet and softened should be removed and replaced prior to
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EEC Project No. 1132073
October 11, 2013
Page 7
placement of flatwork or pavements. Over densification of the subgrade soils under construction
traffic could significantly increase the potential for post-construction heaving in the cohesive
subgrades. Care should be taken to maintain proper moisture contents in the subgrade soils prior
to placement of any overlying improvements.
Field percolation tests were completed at three (3) locations on the site. The test locations and
measured percolation rates are shown on the boring location diagram. The percolation rates
ranged from 120 minutes/inch to “did not perc”. We expect the site lean clays where compacted
for support of site pavements would show low percolation rates.
Pavement Design Sections
We expect the site pavements will include areas designated for automobile traffic and areas for
possible slightly heavier duty drive lanes. For design of heavy-duty areas, we have assumed an
equivalent daily load axle (EDLA) rating of 10 and an EDLA of 7 for exclusive automobile areas.
Proofrolling and recompacting the subgrade is recommended immediately prior to placement of
the aggregate road base section. Soft or weak areas delineated by the proofrolling 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 pavement areas be designed using an R-value of 5, based on the soils
classifications of the subsoils on-site.
Subgrade stabilization to mitigate for potentially compressible conditions/pumping subgrades in
isolated areas may include incorporation of a chemical treatment such as fly ash to enhance the
subgrade integrity. An alternate would be to over-excavate or “cut to grade” to accommodate a
minimum of 12 inches of non-expansive granular soils to be placed and compacted beneath the
pavement section.
If the fly ash alternative stabilization approach is selected, EEC recommends incorporating
approximately 12% (by weight) Class C fly ash, into the upper 12-inches of subgrade. Hot Mix
Asphalt (HMA) underlain by crushed aggregate base course with or without a fly ash treated
subgrade, and non-reinforced concrete pavement are feasible alternatives for the proposed on-site
paved sections.
Earth Engineering Consultants, LLC
EEC Project No. 1132073
October 11, 2013
Page 8
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 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 TABLE I. The hot mix asphalt (HMA)
pavement should be grading S (75) or SX (75) with PG 58-28 oil. The aggregate base should be
Class 5 or Class 6 base. Portland cement concrete should be a pavement design mix with a
minimum 28-day compressive strength of 4000 psi and should be air entrained. HMA pavements
may show rutting and distress in truck loading or turning areas. Concrete pavements should be
considered in those areas.
TABLE I – RECOMMENDED PAVEMENT SECTIONS
Automobile Parking Heavy Duty Areas
EDLA
Reliability
Resilient Modulus
PSI Loss
7
65%
3025
2.5
10
75%
3025
2.2
Design Structure Number 2.50 2.79
Composite: Alternative A
Hot Bituminous Pavement
Aggregate Base
Design Structure Number
4"
7"
(2.53)
4-1/2"
8"
(2.86)
Composite: Alternative B
Hot Bituminous Pavement
Aggregate Base
(1) Fly Ash Treated Subgrade
Design Structure Number
3"
6"
12"
(2.58)
3-1/2"
6"
12"
(2.80)
(1) For use of fly ash in the on-site pavement areas for stabilization purposes, it is recommended that at least
the upper 12-inches of the prepared subgrade be treated with approximately 13% fly ash (by weight) of
Class C fly ash.
Earth Engineering Consultants, LLC
EEC Project No. 1132073
October 11, 2013
Page 9
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 as outlined by ACI criteria. All joints
should be sealed to prevent entry of foreign material and dowelled where necessary for load
transfer.
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:
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.
Earth Engineering Consultants, LLC
EEC Project No. 1132073
October 11, 2013
Page 10
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, rutting, or excessive drying. 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 stabilization or 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.
Other Considerations
Positive drainage should be developed away from the structure and pavement areas 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 adjacent to the building and parking and
drive areas to avoid features which would pond water adjacent to the pavement, 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.
Lawn watering systems should not be placed within 5 feet of the perimeter of the building and
parking areas. Spray heads should be designed not to spray water on or immediately adjacent to
the structure or site pavements. Roof drains should be designed to discharge at least 5 feet away
from the structure and away from the pavement areas.
Excavations into the on-site soils may encounter a variety of conditions. Excavations into the on-
site clays can be expected to stand on relatively steep temporary slopes during construction.
However, if excavations extend into the underlying 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.
Earth Engineering Consultants, LLC
EEC Project No. 1132073
October 11, 2013
Page 11
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. Site-specific explorations should be
completed to develop site-specific recommendations for each of the site buildings.
This report has been prepared for the exclusive use for Mr. Steve Allen/Geico Insurance 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.
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.
HARDNESS AND DEGREE OF CEMENTATION:
GEICO OFFICE BUILDING
FORT COLLINS, COLORADO
EEC PROJECT NO. 1132073
SEPTEMBER 2013
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
SPARSE VEGETATION _ _
APPARENT FILL MATERIAL 1
Sandy Lean Clay with trace Gravel _ _
2
_ _
CS 3 8 4000 10.5 117.6
_ _
4
SANDY LEAN CLAY (CL) _ _
brown SS 5 8 8000 16.8
stiff to very stiff _ _
6
_ _
7
_ _
8
_ _
9
_ _
brown / red CS 10 8 7000 16.4 110.4 35 18 67.6 <500 None
with traces of gravel _ _
11
_ _
12
_ _
13
_ _
14
_ _
SS 15 2 -- 14.8
_ _
16
_ _
17
gravel seams _ _
18
_ _
19
_ _
CS 20 13 6000 21.1 107.5
BOTTOM OF BORING DEPTH 20.0' _ _
21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
GEICO OFFICE BUILDING
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
SPARSE VEGETATION _ _
APPARENT FILL MATERIAL 1
Sandy Lean Clay with trace Gravel _ _
2
_ _
3
SANDY LEAN CLAY (CL) _ _
brown 4
stiff to very stiff _ _
CS 5 11 4000 16.9 107.8 41 26 65.9 600 psf 0.1%
_ _
6
_ _
7
_ _
8
_ _
9
_ _
brown / red SS 10 11 3000 7.3
with traces of gravel _ _
11
_ _
12
_ _
13
_ _
14
_ _
CS 15 3 3000 10.1 112.2
_ _
16
_ _
17
_ _
18
_ _
19
_ _
SS 20 13 7000 18.5
_ _
BOTTOM OF BORING DEPTH 20.5' 21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
GEICO OFFICE BUILDING
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
SPARSE VEGETATION _ _
APPARENT SURFICIAL LAYER OF FILL MATERIAL 1
Sandy Lean Clay , brown _ _
2
SANDY LEAN CLAY (CL) _ _ % @ 150 psf
brown CS 3 15 9000 16.9 109.5 39 22 72.4 1700 psf 2.0%
stiff to very stiff _ _
4
_ _
SS 5 7 9000 20.8
_ _
6
_ _
7
_ _
8
_ _
9
_ _
brown / red SS 10 7 8000 20.1
_ _
BOTTOM OF BORING DEPTH 10.5' 11
_ _
12
_ _
13
_ _
14
_ _
15
_ _
16
_ _
17
_ _
18
_ _
19
_ _
20
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21
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22
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23
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24
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25
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Earth Engineering Consultants, LLC
GEICO OFFICE BUILDING
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
SPARSE VEGETATION _ _
1
SANDY LEAN CLAY (CL) _ _
brown 2
stiff to very stiff _ _ % @ 150 psf
with calcareous deposits CS 3 22 9000+ 12.6 116.8 36 18 63.4 6500 psf 8.3%
_ _
4
_ _
SS 5 11 9000+ 14.7
_ _
6
_ _
7
_ _
8
_ _
9
brown / red _ _
SS 10 6 6000 15.5
_ _
BOTTOM OF BORING DEPTH 10.5' 11
_ _
12
_ _
13
_ _
14
_ _
15
_ _
16
_ _
17
_ _
18
_ _
19
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20
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21
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22
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23
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24
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25
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Earth Engineering Consultants, LLC
GEICO OFFICE BUILDING
Project:
Location:
Project #:
Date:
Geico Office
Fort Collins, Colorado
1132073
September 2013
Beginning Moisture: 16.4% Dry Density: 113 pcf Ending Moisture: 19.2%
Swell Pressure: <500 psf % Swell @ 500: None
Sample Location: Boring 1, Sample 3, Depth 9'
Liquid Limit: 35 Plasticity Index: 18 % Passing #200: 67.6%
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown Sandy Lean Clay (CL)
-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 Sandy Lean Clay (CL)
Sample Location: Boring 2, Sample 1, Depth 4'
Liquid Limit: 41 Plasticity Index: 26 % Passing #200: 65.9%
Beginning Moisture: 16.9% Dry Density: 113.3 pcf Ending Moisture: 19.0%
Swell Pressure: 600 psf % Swell @ 500: 0.1%
Geico Office
Fort Collins, Colorado
1132073
September 2013
-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 Lean Clay with Sand (CL)
Sample Location: Boring 3, Sample 1, Depth 2'
Liquid Limit: 39 Plasticity Index: 22 % Passing #200: 72.4%
Beginning Moisture: 16.9% Dry Density: 116.4 pcf Ending Moisture: 18.8%
Swell Pressure: 1700 psf % Swell @ 150: 2.0%
Geico Office
Fort Collins, Colorado
1132073
September 2013
-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 Sandy Lean Clay (CL)
Sample Location: Boring 4, Sample 1, Depth 2'
Liquid Limit: 36 Plasticity Index: 18 % Passing #200: 63.4%
Beginning Moisture: 12.6% Dry Density: 116.8 pcf Ending Moisture: 17.2%
Swell Pressure: 6500 psf % Swell @ 150: 8.3%
Geico Office
Fort Collins, Colorado
1132073
September 2013
-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
FORT COLLINS, COLORADO
PROJECT NO: 1132073 LOG OF BORING B-4 SEPTEMBER 2013
SHEET 1 OF 1 WATER DEPTH
START DATE 9/20/2013 WHILE DRILLING None
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 9/20/2013 AFTER DRILLING N/A
A-LIMITS SWELL
FORT COLLINS, COLORADO
PROJECT NO: 1132073 LOG OF BORING B-3 SEPTEMBER 2013
SHEET 1 OF 1 WATER DEPTH
START DATE 9/20/2013 WHILE DRILLING None
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 9/20/2013 AFTER DRILLING N/A
A-LIMITS SWELL
FORT COLLINS, COLORADO
PROJECT NO: 1132073 LOG OF BORING B-2 SEPTEMBER 2013
SHEET 1 OF 1 WATER DEPTH
START DATE 9/20/2013 WHILE DRILLING 15.0'
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 9/20/2013 AFTER DRILLING N/A
*close evaluation of fill material should be provided
during foundation excavation phase prior to
placement of foundation forms
A-LIMITS SWELL
FORT COLLINS, COLORADO
PROJECT NO: 1132073 LOG OF BORING B-1 SEPTEMBER 2013
SHEET 1 OF 1 WATER DEPTH
START DATE 9/20/2013 WHILE DRILLING 17.0'
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 9/20/2013 AFTER DRILLING N/A
*close evaluation of fill material should be provided
during foundation excavation phase prior to
placement of foundation forms
A-LIMITS SWELL
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