HomeMy WebLinkAboutCARGILL EXPANSION - PDP/FDP - FDP130043 - SUBMITTAL DOCUMENTS - ROUND 1 - RECOMMENDATION/REPORTEARTH ENGINEERING
CONSULTANTS, LLC
April 19, 2013
Dohn Construction, Inc.
2642 Midpoint Drive
Fort Collins, Colorado 80525
Attn: Mr. Todd Annand (tannand@dohnconstruction.com)
Re: Geotechnical Exploration Report
Proposed Greenhouse Additions
Cargill Food Services
2540 East County Road 42 (Drake Road)
Fort Collins, Colorado
EEC Project No. 1132019
Mr. Annand:
As requested, Earth Engineering Consultants, LLC (EEC) personnel have completed an
evaluation of soil conditions in the area of the proposed greenhouse additions to be
constructed at the Cargill Food Service facility at 2540 East Drake Road in Fort Collins,
Colorado. Results of that subsurface evaluation are provided with this report.
We understand the proposed greenhouse additions will be single-story structures with
plan dimensions of approximately 104 feet by 108 feet and 104 feet by 42 feet. We
expect foundation loads for the structures will be light with column loads less than 50
kips. We understand the larger addition would be supported on shallow pier foundations
and the smaller addition on conventional footing/stem walls as site conditions allow.
Floor loads will be light. Small grade changes are expected in the area of the new
greenhouse additions to develop final site grades.
The purpose of this report is to describe the subsurface conditions encountered in the test
borings completed on the site and provide geotechnical recommendations concerning
design and construction of foundations and support of floor slabs.
Earth Engineering Consultants, LLC
EEC Project No. 1132019
April 19, 2013
Page 2
As a part of our evaluation, three (3) soil borings were extended to depths of
approximately 20 feet below present site grades to develop information on existing
subsurface conditions in the area of the proposed structures. The anticipated location of
the structures was identified in the field by others. An EEC field engineer was on site
during drilling to evaluate the subsurface conditions encountered and direct the drilling
activities. Samples of the subsurface materials encountered were obtained from split
barrel and California barrel sampling procedures. All samples obtained in the field were
sealed and returned to our laboratory for further examination, classification and testing.
Laboratory testing on the recovered samples included moisture content and visual
classification of all samples. The unconfined strength of appropriate samples was
estimated with a calibrated hand penetrometer. In addition, the quantity and plasticity of
the fines in the subgrade was evaluated with washed sieve analysis and Atterberg limits
tests. Swell/consolidation tests were performed on representative samples to evaluate the
soil's tendency 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.
Based on results of field borings and laboratory testing on the recovered samples,
subsurface conditions can be generalized as follows. Vegetation and topsoil was
encountered at the surface at the boring locations. The vegetation/topsoil was underlain
by brown sandy lean clay. The lean clay soils were stiff to very stiff and extended to
depths of approximately 18 feet. Swell test results indicate generally low swell potential
although the sample from a depth of 2 feet in boring B-2 showed higher swell. The sandy
lean clays were underlain by dense sands and gravels. The granular soils extended to the
bottom of the borings at depths of approximately 20 feet below present site grades. The
stratification boundaries indicated on the boring logs represent the approximate locations
of changes in soil types. The material change in-situ can be gradual and indistinct.
Observations were made at the time of drilling to evaluate the presence and depth to the
hydrostatic groundwater table. Free water was observed at depths of approximately 19
feet in each of the borings at the time of drilling. 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.
Earth Engineering Consultants, LLC
EEC Project No. 1132019
April 19, 2013
Page 3
ANALYSIS AND RECOMMENDATIONS
Foundations – Drilled Piers
We understand the client would prefer the new larger greenhouse structure be supported
on shallow drilled piers. Based on the materials observed at the boring locations, it is our
opinion the proposed lightly loaded structure could be supported on shallow drilled piers
bearing in the natural site soils. Allowable end bearing and skin friction values for
shallow drilled pier design are provided below in Table 1.
Table 1: Recommended Drilled Pier Allowable End Bearing and Skin Friction
Depth Below Surface
(feet)
End Bearing
Qp (psf)
Skin Friction
fs (psf)
4 1500 150
6 1750 175
8 2000 200
10 2250 225
For design of drilled pier foundations bearing on the natural stiff to very stiff sandy lean
clay, pier lengths can be determined once column loads are known using the values
provided in Table 1. Skin friction should be neglected for the upper 3 feet below
adjacent ground surface. Linear interpolation may be used between the table values.
Total structure load should include full dead and live loads. The pier foundations should
have a minimum pier length of 6 feet.
Care should be taken during pier construction to avoid sloughing of the drilled excavation
sidewalls into the open pier hole. Based on the materials observed in the borings, we do
not believe temporary casing will be needed to construct the drilled piers. However, free
water and granular soils were observed at depths of approximately 18 feet; piers
extending below that depth would require additional evaluation and potentially deeper
exploration borings.
Earth Engineering Consultants, LLC
EEC Project No. 1132019
April 19, 2013
Page 4
Pier concrete should be placed as soon as possible after completion of the drilled
excavations. We recommend the pier concrete have a minimum slump of 5 inches and
maximum slump of 8 inches.
We estimate the long-term settlement of the drilled pier foundations designed and
constructed as outlined above would be less than 1 inch.
Foundations - Conventional Footings
We understand the smaller greenhouse addition would be supported on a conventional
footing/stem wall foundation system. Footing foundations could be supported on the
natural, stiff to very stiff sandy lean clay using a net allowable total load soil bearing
pressure not to exceed 1,500 psf. The net bearing pressure refers to pressure at
foundation bearing level in excess of the minimum surrounding overburden pressure.
Exterior perimeter foundations and foundations in unheated areas should bear at least 30
inches below adjacent exterior grade to provide frost protection. We recommend formed
continuous footings have a minimum width of 24 inches.
The soil at a depth of 2 feet in boring B-2 showed low moisture and high density with
resulting moderate swell potential. Care should be taken at the time of construction to
see that the footings (and floor slabs) are not supported on or directly above expansive
subgrade materials. Support of the footings on dry, dense expansive clays may result in
unacceptable movement of the site structure.
We estimate the long term settlement of footing foundations designed and constructed as
outline above would be less than 1 inch.
Floor and Slab-on-Grade Subgrades
All existing vegetation and/or topsoil should be removed from floor and exterior slab-on-
grade areas. In addition, the in-place subgrades should be closely observed for dry, dense
cohesive near surface material at the time of construction. As identified in boring B-2,
Earth Engineering Consultants, LLC
EEC Project No. 1132019
April 19, 2013
Page 5
higher swells may be observed in dry, dense subgrade materials. If observed at the time
of construction, those materials should be removed from below any floor slabs and/or
flatwork. We suggest removing 12 to 18 inches of in-place material prior to scarification
of exposed subgrades could be considered to address potential in-place moderately
expansive material. The removed materials could be used for fill to develop site
subgrades with appropriate moisture/density control as outlined below.
After stripping and completing all cuts and prior to placement of any fill, floor slabs or
exterior slabs, we recommend the in-place soils be scarified to a minimum depth of 9
inches, adjusted in moisture content and compacted to at least 95% of the material's
maximum dry density as determined in accordance with ASTM Specification D-698, the
standard Proctor procedure. The moisture content of the scarified soils should be
adjusted to be within the range of 2% of standard Proctor optimum moisture at the time
of compaction.
Fill soils required to develop structure subgrades should consist of approved, low-volume
materials which are free from organic matter and debris. The near surface sandy lean
clay could be used as fill beneath the floor slabs or exterior slab-on-grade with
appropriate moisture/density control. We recommend those fill soils be placed in loose
lifts not to exceed 9 inches thick, adjusted in moisture content as recommended for the
scarified materials and compacted to at least 95% of the material's standard Proctor
maximum dry density.
After preparation of the subgrades, care should be taken to avoid disturbing the in-place
materials. Soils which are loosened or disturbed by the construction activities or
materials which become dry and desiccated or wet and softened should be reworked in
place or removed and replaced prior to placement of the overlying improvements.
Particular care will be needed in the sandy clay subgrades to maintain the outlined
moisture and density in the subgrades prior to placement of overlying floors or flatwork.
Earth Engineering Consultants, LLC
EEC Project No. 1132019
April 19, 2013
Page 6
Other Considerations
Positive drainage should be developed away from the new structure with a minimum
slope of 1 inch per foot for the first 10 feet away from the building. Care should be taken
in landscaping adjacent to the structure to avoid features which pond water next to the
building or in placement of plants next to the building which create moisture fluctuations
in the subgrades.
Soluble sulfate testing of the site soils indicated a soluble sulfate content of
approximately 14mg/kg as SO4. The low soluble sulfate content indicates low potential for
sulfate attack on site cast concrete.
General
The analysis and recommendations presented in this report are based upon the data
obtained from the borings completed 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 that 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 and foundation construction phases to help determine that
the design requirements are fulfilled.
This report has been prepared for the exclusive use of Dohn Construction, Inc. 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
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:
CARGILL GREENHOUSE ADDITIONS
FORT COLLINS, COLORADO
EEC PROJECT NO. 1132019
APRIL 2013
DATE:
RIG TYPE: CME45
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: MANUAL
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
TOPSOIL & VEGETATION _ _
1
SANDY LEAN CLAY (CL) _ _
brown 2
stiff to very stiff _ _
3
_ _
4
_ _
CS 5 10 9000+ 11.7 94.2 30 9 80.7 1050 psf 0.9%
_ _
6
_ _
7
_ _
8
_ _
9
_ _
brown / red SS 10 9 9000+ 15.3
_ _
11
_ _
12
_ _
13
_ _
14
_ _
brown / red / tan CS 15 16 -- 17.1 114.2
_ _
16
_ _
17
_ _
18
_ _
SAND & GRAVEL (SP/GP) 19
very dense _ _
SS 20 50 -- 10.3
_ _
BOTTOM OF BORING DEPTH 20.5' 21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
A-LIMITS SWELL
DATE:
RIG TYPE: CME45
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: MANUAL
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
TOPSIL & VEGETATION _ _
1
SANDY LEAN CLAY (CL) _ _
brown 2
stiff to very stiff _ _ % @ 150 psf
CS 3 17 9000+ 7.2 110.6 34 18 79.1 1250 psf 4.5%
_ _
4
_ _
CS 5 5 9000+ 8.2
_ _
6
_ _
7
_ _
8
_ _
9
_ _
brown / red SS 10 16 9000+ 13.2 120.9 34 20 60.7 1400 psf 0.7%
with traces of gravel _ _
11
_ _
12
_ _
13
_ _
14
_ _
brown / grey / rust SS 15 11 6000 15.0
_ _
16
_ _
17
_ _
18
_ _
SAND & GRAVEL (SP/GP) 19
very dense _ _
SS 20 50 -- 10.6
_ _
BOTTOM OF BORING DEPTH 20.5' 21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
A-LIMITS SWELL
DATE:
RIG TYPE: CME45
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: MANUAL
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
TOPSOIL & VEGETATION _ _
1
SANDY LEAN CLAY (CL) _ _
brown 2
stiff to very stiff _ _
3
_ _
4
_ _
CS 5 7 9000+ 8.6 70.9 34 18 83.4 1150 psf 0.9%
_ _
6
_ _
7
_ _
8
_ _
9
brown / red _ _
SS 10 10 9000+ 13.4
_ _
11
_ _
12
_ _
13
_ _
14
_ _
with traces of gravel CS 15 12 8000 15.9 115.6
_ _
16
_ _
17
_ _
18
_ _
SAND & GRAVEL (SP/GP) 19
dense _ _
SS 20 28/7" 9000+ 8.6
_ _
BOTTOM OF BORING DEPTH 20.5' 21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
A-LIMITS SWELL
Project:
Location:
Project #:
Date:
Cargill Greenhouse Additions
Fort Collins, Colorado
1132019
April 2013
Beginning Moisture: 11.7% Dry Density: 96.5 pcf Ending Moisture: 25.0%
Swell Pressure: 1050 psf % Swell @ 500: 0.9%
Sample Location: Boring 1, Sample 1, Depth 4'
Liquid Limit: 30 Plasticity Index: 9 % Passing #200: 80.7%
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 2'
Liquid Limit: 34 Plasticity Index: 18 % Passing #200: 79.1%
Beginning Moisture: 7.2% Dry Density: 103.1 pcf Ending Moisture: 23.4%
Swell Pressure: 1250 psf % Swell @ 150: 4.5%
Cargill Greenhouse Additions
Fort Collins, Colorado
1132019
April 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 / Red Sandy Lean Clay (CL)
Sample Location: Boring 2, Sample 3, Depth 9'
Liquid Limit: 34 Plasticity Index: 20 % Passing #200: 60.7%
Beginning Moisture: 13.2% Dry Density: 119.1 pcf Ending Moisture: 14.3%
Swell Pressure: 1400 psf % Swell @ 500: 0.7%
Cargill Greenhouse Additions
Fort Collins, Colorado
1132019
April 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 3, Sample 1, Depth 4'
Liquid Limit: 34 Plasticity Index: 18 % Passing #200: 83.4%
Beginning Moisture: 8.6% Dry Density: 100.2 pcf Ending Moisture: 26.5%
Swell Pressure: 1150 psf % Swell @ 500: 0.9%
Cargill Greenhouse Additions
Fort Collins, Colorado
1132019
April 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
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 4/8/2013 AFTER DRILLING N/A
SHEET 1 OF 1 WATER DEPTH
START DATE 4/8/2013 WHILE DRILLING 19.0'
CARGILL GREENHOUSE ADDITIONS
FORT COLLINS, COLORADO
PROJECT NO: 1132019 LOG OF BORING B-3 APRIL 2013
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 4/8/2013 AFTER DRILLING N/A
SHEET 1 OF 1 WATER DEPTH
START DATE 4/8/2013 WHILE DRILLING 19.0'
CARGILL GREENHOUSE ADDITIONS
FORT COLLINS, COLORADO
PROJECT NO: 1132019 LOG OF BORING B-2 APRIL 2013
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 4/8/2013 AFTER DRILLING N/A
SHEET 1 OF 1 WATER DEPTH
START DATE 4/8/2013 WHILE DRILLING 19.5'
CARGILL GREENHOUSE ADDITIONS
FORT COLLINS, COLORADO
PROJECT NO: 1132019 LOG OF BORING B-1 APRIL 2013
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