HomeMy WebLinkAboutAGNEW CAR WASH - PDP - 32-06 - SUBMITTAL DOCUMENTS - ROUND 1 - RECOMMENDATION/REPORTUNIFIED SOIL CLASSIFICATION SYSTEM
Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests"
Soil Classification
Group
Symbol
Group Namea
Coarse Grained Soils
Gravels
Clean Gravels
Cu z 4 and 1 s Cc s 3E
GW
Well -graded gravel`
More than 50% retained
More than 50% of coarse
fraction retained on
Less than 5% fines`
Cu <4 and/or 1 > Cc> 31
GP
Poorly graded gravel`
on No. 200 sieve
No. 4 sieve
Gravels with Fines More Fines classify as ML or MH
GM
Silty gravel`•`•"
than 12% finesc
Fines classify as CL or CH
GC
FGH
Clayey gravel
Sands
Clean Sands
Cu a 6 and 1 s Cc s 36
SW
Well -graded sand'
50% or more of coarse
fraction passes
Less than 5% fines°
Cu < 6 and/or 1 > Cc > 3E
SP
Poorly graded sand'
No. 4 sieve
Sands with Fines
Fines classify as ML or MH
SM
Silty sand'"'
More than 12% fines°
Fines Classify as CL or CH
SC
Clayey sands"'
Fine -Grained Soils
Sifts and Clays
inorganic
PI > 7 and plots on or above "A" line'
CL
Lean clay""
50% or more passes the .
Liquid limit less than 50
PI <4 or plots below "A" line'
ML
Silt"`
No. 200 sieve
organic
Liquid limit - oven dried
Organic day"" "'
< D.75
OL
Liquid limit - not dried
Organic SiltK 1 M O
Silts and Clays
inorganic
PI plots on or above "A" line
CH
Fat clay"•""
Liquid limit 50 or more
PI lots below 'A* line
MH
Elastic Silt""'
organic
Liquid limit - oven dried
Organic clay'
<0.75
OH
Liquid limit - not dried
Organic siltK-'�O
Highly organic soils
Primarily organic matter, dark in
color, and organic odor
PT
Peat
"Based on the material passing the 3-in. (75-mm) sieve
e If field sample contained cobbles or boulders, or both, add "with cobbles
or boulders, or both" to group name.
°Gravels with 5 to 12% fines require dual symbols: GW-GM well -graded
gravel with silt, GW-GC well -graded gravel with clay, GP -GM poorly
graded gravel with silt, GP -GC poorly graded gravel with clay.
°Sands with 5 to 12% fines require dual symbols: SW-SM well -graded
sand with silt, SW -SC well -graded sand with clay, SP-SM poorly graded
sand with silt, SP-SC poorly graded sand with clay
z
FCu = Deo/Dro Cc = (D,,
Dio X Deo
F If soil contains >_ 15% sand, add 'with sand" to group name.
off fines classify as CL-ML, use dual symbol GC -GM, or SC-SM.
60
50
d
W 40
Z
Y 30
U
g20
n-
10
7
4
"If fines are organic, add "with organic fines" to group name.
If soil contains > 15% gravel, add "with gravel" to group name.
' If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay.
K If soil contains 15 to 29% plus No. 200, add "with sand" or "with
gravel," whichever is predominant.
L If soil contains >_ 30% plus No. 200 predominantly sand, add
"sandy" to group name.
°Alf soil contains >_ 30% plus No. 200, predominantly gravel, add
"gravelly" to group name.
"PI >_ 4 and plots on or above "A" line.
°PI < 4 or plots below "A" line.
PI plots on or above "A" line.
OR plots below "A" line.
— --r_
j
—
For classification of fine-grained
soils and fine-grained fraction
_of coarse -grained soils ___
_—�xp0,'� I ce
Equation of "A" • line
Horizontal at P1=4 to LL=25.5.
F_ then PI=0.73 (LL-2o)
i
Equation of "U" -line
O
dI,
'--
Vertical at LL=16 to PI=7,
--'--
—�
�— then PI=0.9 (LL-8)
O
I I
'
MH or OH
_
77;
ML or OL
I
�
0 10 16 20 30 40 50 60 70 90 90 100 110
LIQUID LIMIT (ILL)
Irerracon
Fom 111--6/98
GENERAL NOTES
DRILLING & SAMPLING SYMBOLS
SS:
Split Spoon - 1 3/8" I.D., 2" O.D., unless otherwise noted
HS:
Hollow Stem Auger
ST:
Thin -Walled Tube - 2" O.D., unless otherwise noted
PA:
Power Auger
RS:
Ring Sampler- 2.42" I.D., 3" O.D., unless otherwise noted
HA:
Hand Auger
DB:
Diamond Bit Coring - 4", N, B
RB:
Rock Bit
BS:
Bulk Sample or Auger Sample
WB:
Wash Boring or Mud Rotary
The number of blows required to advance a standard 2-inch O.D. split -spoon sampler (SS) the last 12 inches of the total 18-inch
penetration with a 140-pound hammer falling 30 inches is considered the "Standard Penetration" or "N-value". For 3" O.D. ring samplers
(RS) the penetration value is reported as the number of blows required to advance the sampler 12 inches using a 140-pound hammer
falling 30 inches, reported as "blows per foot," and is not considered equivalent to the "Standard Penetration"or "N-value ".
WATER LEVEL MEASUREMENT SYMBOLS
WL:
Water Level
WS:
While Sampling N/E: Not Encountered
WCI:
Wet Cave in
WD:
While Drilling
DCI:
Dry Cave in
BCR:
Before Casing Removal
AB:
After Boring
ACR:
After Casing Removal
Water levels indicated on the boring logs are the levels measured in the borings at the times indicated. Groundwater levels at other
times and other locations across the site could vary. In pervious soils, the indicated levels may reflect the location of groundwater. In
low permeability soils, the accurate determination of groundwater levels may not be possible with only short-term observations.
DESCRIPTIVE SOIL CLASSIFICATION: Soil classification is based on the Unified Classification System. Coarse Grained Soils have
more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine
Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic,
and silts if they are slightly plastic or non -plastic. Major constituents may be added as modifiers and minor constituents may be added
according to the relative proportions based on grain size. In addition to gradation, coarse -grained soils are defined on the basis of their
in -place relative density and fine-grained soils on the basis of their consistency.
CONSISTENCY OF FINE-GRAINED SOILS
Standard
Unconfined
Penetration or
Compressive
N-value (SS)
Strength, Qu, psf
Blows/Ft.
Consistency
< 500
<2
Very Soft
500 — 1,000
2-3
Soft
1,001 — 2,000
4-6
Medium Stiff
2,001 — 4.000
7-12
Stiff
4,001 — 8,000
13-26
Very Stiff
8,000+
26+
Hard
RELATIVE PROPORTIONS OF SAND AND GRAVEL
Descriptive Term(s) of other
Percent of
constituents
Dry Weight
Trace
< 15
With
15 — 29
Modifier
> 30
RELATIVE PROPORTIONS OF FINES
Descriptive Term(s) of other
Percent of
constituents
Dry Weight
Trace < 5
With 5-12
Modifiers > 12
RELATIVE DENSITY OF COARSE -GRAINED SOILS
Standard
Penetration or
N-value (SS)
Ring Sampler (RS)
Blows/Ft.
Blows/Ft.
Relative Density
0-3
0-6
Very Loose
4-9
7-18
Loose
10-29
19-58
Medium Dense
30 — 49
59-98
Dense
50+
99+
Very Dense
GRAIN SIZE TERMINOLOGY
Maior Component
of Sample Particle Size
Boulders
Over 12 in. (300mm)
Cobbles
12 in. to 3 in. (300mm to 75 mm)
Gravel
3 in. to #4 sieve (75mm to 4.75 mm)
Sand
#4 to #200 sieve (4.75mm to 0.075mm)
Silt or Clay
Passing #200 Sieve (0.075mm)
PLASTICITY DESCRIPTION
Term Plasticity Index
Non -plastic
0
Low
1-10
Medium
11-30
High
30+
Irerracon
r_>a»CHI MMR
lrerracon
-6
-4
-2
Cn
M
m
r oil
0
n
O
z
O
r
0 2
D
1
O
z
4
6
8
0.01 0.1 1 10
APPLIED PRESSURE, TSF
e
Specimen Identification
Classification
Y
m
11
0
J
h Notes:
Z
O
U
a
C7
m
0
N
O
O
O
z
CONSOLIDATION TEST
a
Project: Proposed Car Wash Facility
Irerracon
Site: S/E/C of Mulbery St. and Lemay Ave. Fort Collins, Colorado
N
0
Job #: 20065109
Date: 8-14-06
Ya, pcf
WC,%
•
4 1.Oft
FILL MATERIAL: CLAYEY SAND
122
7
cn
m
m
r
r
0
0
0
Z
N
O
r
O
D
O
Z
3L
J.1
APPLIED PRESSURE, TSF
Specimen Identification
Classification
Yd, pcf
WC,%
G
3 4.Oft
1 SANDY LEAN CLAY
115
7
Notes:
Z CONSOLIDATION TEST
a
y Project: Proposed Car Wash Facility
Irerracon Site: S/E/C of Mulbery St. and Lemay Ave. Fort Collins, Colorado
o Job M 20065109
U
F Date: 8-14-06
0)
m
m
r
r
n
O
z
cn
O
r
v
D
--I
O
z
6
4
2
00
4
6
8
0.1
1 11
APPLIED PRESSURE, TSF
Specimen Identification
Classification
Ya, pcf
WC,%
101
1 4.Oft
SANDY LEAN CLAY
103
12
Notes:
CONSOLIDATION TEST
Project: Proposed Car Wash Facility
Irerracon Site: S/E/C of Mulbery St. and Lemay Ave. Fort Collins, Colorado
Job M 20065109
60
CL CH
50
P
L
A
40
s
T
I
C
T 30
Y
I
N 20
D
E
X
10
ML
EH
CL-ML
20 40 60 80 100
LIQUID LIMIT
Specimen Identification
LL
PL
PI
%Fines
Classification
•
2 4.0ft
NP
NP
NP
25
SILTY SAND with GRAVEL(SM)
m
4 2.Oft
31
13
18
49
CLAYEY SAND(SC)
's
i
t
,
,
,
Irerracon
ATTERBERG LIMITS RESULTS
Project: Proposed Car Wash Facility
Site: S/E/C of Mulbery St. and Lemay Ave. Fort Collins, Colorado
Job #: 20065109
Date: 8-14-06
APPENDIX B
LOG OF BORING NO. 4
Page 1 of 1
CLIENT
ARCHITECT / ENGINEER
John Agnew
SITE S/E/C of MulberySt. and Lemay Ave.
PROJECT
Fort Collins, Colorado
Proposed Car Wash Facility
SAMPLES
TESTS
0
DESCRIPTION
p
Co
o 0
Cn
m
z
z
LLo
zoco
�
a
U
iaU
I
Wz
00
>
W
U
Approx.
Surface Elev.: 97.48 ft
o
Z)
z
HIt
Cn m
of
0a
z
FILL MATERIAL
Clayey Sand
Brown, stiff to very stiff, trace gravel
CL
1 IRS1
12
34
6.8
122
CL
2 �SS
1
12
32
4.5
3
94.5
SILTY SAND WITH GRAVEL
SM
3
SS
NR
31
Brown, dense to very dense
5
t
SM
4
JACI
'.
g 88.5
0.8
BOTTOM OF BORING
* "AC" DENOTES AUGER CUTTINGS
COLLECTED DUE TO HOLE COLAPSE
e
m
0
Z
0
U
Q
K
Wd'
F
The stratification lines represent the approximate boundary lines
o between soil and rock types: in -situ, the transition may be gradual.
o WATER LEVEL OBSERVATIONS, ft
BORING STARTED 7-21-06
m WL �Z DRY WD IT 6 AB
ifierracon
BORING COMPLETED 7-21-06
WL
RIG CME-55
FOREMAN CMG
o WL
m
Water Level Reading on 8/15/06
APPROVED DAR I
JOB # 20065109
LOG OF BORING NO. 3
Page 1 of 1
CLIENT
ARCHITECT! ENGINEER
John Agnew
SITE S/E/C of Mulbery St. and Lemay Ave.
PROJECT
Fort Collins, Colorado
Proposed Car Wash Facility
SAMPLES
TESTS
DESCRIPTION
O
❑ a
Z
L)UL
3
}
r
F
cn
W
W
O
?�
0Z
"
Approx. Surface Elev.: 98.96 ft
o
z
r
(t
v, m
F-Z
� o
}
o a
Z) v~i
FILL MATERIAL
Sandy Lean Clay with Gravel
Brown, stiff to very stiff
2
97
SANDY LEAN CLAY
Brown, hard
CL
1
RS
12
36
6.9
115
5
6 93
SILTY SAND WITH GRAVEL
Brown, dense to very dense, trace cobbles
encountered
SM
2
1 SS
12
50/0.1
4.3
�
10
SM
3
JACI
12
5.4
14 85
BOTTOM OF BORING
0
"'AC DENOTES AUGER CUTTINGS
COLLECTED DUE TO HOLE COLAPSE
0
i
0
U
Q
K
WK
F
The stratification lines represent the approximate boundary lines
o between soil and rock types: in -situ, the transition may be gradual.
o WATER LEVEL OBSERVATIONS, ft
N
Irerracon
BORING STARTED 7-21-06
WL
-7 DRY WD
IT 10.0 AB
7-21-06
COME
0 WL
s
RIG55EDFOREMAN
CMG
m WL
Water Level Reading on 8/15/O6
APPROVED DAR
JOB # 20065109
LOG OF BORING NO. 2
Page 1 of 1
CLIENT
ARCHITECT / ENGINEER
John Agnew
SITE S/E/C of Mulbery St. and Lemay Ave.
PROJECT
Fort Collins, Colorado
Proposed Car Wash Facility
SAMPLES
TESTS
DESCRIPTION
F
Z
U
U
0
42
z
_
z
F
zz
S
ad
rn
W
coW
O
zco
0
�
OW
(D
Approx. Surface Elev.: 97.93 ft
W
o
(n
D
z
}
W
Of
d�
U) m
a0
3 0
ofz�
o a
7) rn
FILL MATERIAL
Sandy Lean Clay with Gravel
Brown, stiff to very stiff
3 95
SILTY SAND WITH GRAVEL
Brown, dense to very dense, trace cobbles
encountered
SM
1
RS
12
50/0.6133.0
5
i
SM
2
SS
12
50/0.1
1.1
10
SM
3
�AC
12
3.2
14 &4
BOTTOM OF BORING
"AC" DENOTES AUGER CUTTINGS
COLLECTED DUE TO HOLE COLAPSE
i
i
The stratification lines represent the approximate boundary lines
between soil and rock types: in -situ, the transition may be gradual.
WATER LEVEL OBSERVATIONS, ft
Irerraccin
BORING STARTED 7-21-06
i WL
DRY WD
Z 6 AB
COMPLETED7 -21-06
WL
�
Y
ROBING
CME-55I
FOREMAN CMG
WL
Water Level Reading on 8/15/06
APPROVED DAR
JOB # 20065109
LOG OF BORING NO. 1
Page 1 of 1
CLIENT
ARCHITECT / ENGINEER
John Agnew
SITE S/E/C of Mulbery St. and Lemay Ave.
PROJECT
Fort Collins, Colorado
Proposed Car Wash Facility
SAMPLES
TESTS
c9
DESCRIPTION
J
m
}
o
w n
U_
Z
LL~
ui
U)
U)
W
m
W
O
z�
W�
?
ZZ
OW
Approx. Surface Elev.: 98.96 ft
❑
ai
❑
7
z
r
w
Q�
a
U) m
QO
3: ❑
K
❑ a
zlr
❑ U)
FILL MATERIAL
Sandy Lean Clay with Gravel
CL
1
SS
12
26
4.7
Brown, very stiff
3 96
SANDY LEAN CLAY
Brown, very stiff
SM
2
RS
12
5010.6
12.2
103
5
7 92
SILTY SAND WITH GRAVEL
Brown, dense to very dense, trace cobbles
encountered
SM
3
SS
12
50/0.1
2.1
10
J':14
SM
4
AC
12
5.6
85
BOTTOM OF BORING
e
"'AC" DENOTES AUGER CUTTINGS
COLLECTED DUE TO HOLE COLAPSE
Z
0
U
Q
cc
WC
F
The stratification lines represent the approximate boundary lines
o between soil and rock types: in -situ, the transition may be gradual.
N
o WATER LEVEL OBSERVATIONS, ft
N
Irerracon
BORING STARTED 7-21-06
WL
4 DRY WD
1 10.5 AB
COMPLETED7 1-06
o WL
w
BORING
CMG
m WL
Water Level Reading on 8/15/06
APPROVED DAR
JOB # 20065109
MULBERRY ST. FRONTAGE RD.
rTBM
I
w I
w
_ #1
O
U)
cD
z
0
J_
DO
S
U #2
o
w
0-
O
0-
0
a
/1 #3
LEGEND
FIGURE 1: SITE DIAGRAM & TEST BORING LOCATIONS
- APPROXIMATE TEST BORING LOCATIONS.
PROPOSED CAR WASH BUILDING
S/E/C OF MULBERRY ST. & LEMAY AVE.
- TBM = TEMPORARY BENCH MARK, SURVEYOR'S
FORT COLLINS, COLORADO
CONTROL POINT, ASSUME ELEV. = 100.0'
Project Mngr. Project No.
Designed ay. DAR 20065109
Designed
lrerracan Scale -
DAR
Checked By: DAR 301 N. Howes Street Date: 8115106
Approved BY Fort Collins, Colorado 80521 Drawn By
DIAGRAM IS FOR GENERAL LOCATION ONLY,
DAR DJS
AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES.
File Name: 20065109-1 Figure No. 1
APPENDIX A
Geotechnical Engineering Report 1rerramn
Proposed Car Wash Facility
SIEIC of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
Surface Drainage
Positive drainage should be provided during construction and maintained throughout the
life of each structure on the site. Infiltration of water into utility or foundation excavations
must be prevented during construction. Planters and other surface features, which could
retain water in areas adjacent to the building or pavements, should be sealed or
eliminated. In areas where sidewalks or paving do not immediately adjoin the structure,
we recommend that protective slopes be provided with a minimum grade of approximately
10-percent for at least 10 feet from perimeter walls. Backfill against footings, exterior
walls, and in utility and sprinkler line trenches should be well compacted and free of all
construction debris to reduce the possibility of moisture infiltration.
Downspouts, roof drains or scuppers should discharge into splash blocks or extensions
when the ground surface beneath such features is not protected by exterior slabs or
paving. Sprinkler systems should not be installed within 10-feet of foundation walls.
Landscaped irrigation adjacent to the foundation system should be minimized or
eliminated.
GENERAL COMMENTS
Terracon should be retained to review the final design plans and specifications so comments can
be made regarding interpretation and implementation of our geotechnical recommendations in the
design and specifications. Terracon also should be retained to provide testing and observation
during excavation, grading, foundation and construction phases of the project.
The analysis and recommendations presented in this report are based upon the data obtained
from the borings performed at the indicated locations and from other information discussed in this
report. This report does not reflect variations that may occur between borings, across the site, or
due to the modifying effects of weather. The nature and extent of such variations may not
become evident until during or after construction. If variations appear, we should be immediately
notified so that further evaluation and supplemental recommendations can be provided.
The scope of services for this project does not include either specifically or by implication any
environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or
prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the
potential for such contamination or pollution, other studies should be undertaken.
This report has been prepared for the exclusive use of our client for specific application to the
project discussed and has been prepared in accordance with generally accepted geotechnical
17
Geotechnical Engineering Report lrerracon
Proposed Car Wash Facility
S/E/C of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
Additional Design and Construction Considerations
Exterior Slab Design and Construction
Compacted subgrade or existing clay soils will expand with increasing moisture content;
therefore, exterior concrete grade slabs may heave, resulting in cracking or vertical
offsets. The potential for damage would be greatest where exterior slabs are constructed
adjacent to the building or other structural elements. To reduce the potential for damage,
we recommend:
• exterior slabs be supported on fill with no, or very low expansion potential
• strict moisture -density control during placement of subgrade fills
• placement of effective control joints on relatively close centers and
isolation joints between slabs and other structural elements
• provision for adequate drainage in areas adjoining the slabs
• use of designs which allow vertical movement between the exterior slabs
and adjoining structural elements
In those locations where movement of exterior slabs cannot be tolerated or must be
reduced, consideration should be given to:
• Constructing slabs with a stem or key -edge, a minimum of 6 inches in
width and at least 12 inches below grade;
• supporting keys or stems on drilled piers; or
• providing structural exterior slabs supported on foundations similar to the
building.
Underground Utility Systems
All piping should be adequately bedded for proper load distribution. It is suggested that
clean, graded gravel compacted to 75 percent of Relative Density ASTM D4253 be used
as bedding. Utility trenches should be excavated on safe and stable slopes in accordance
with OSHA regulations as discussed above. Backfill should consist of the on -site soils or
imported material approved by the geotechnical engineer. The pipe backfill should be
compacted to a minimum of 95 percent of Standard Proctor Density ASTM D698.
16
Geotechnical Engineering Report lliwacon
Proposed Car Wash Facility
S/E/C of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
• Liquid Limit.................................................................................. 30 (max)
• Plasticity Index............................................................................. 15 (max)
• Group Index................................................................................. 10 (max)
Engineered fill should be placed and compacted in horizontal lifts, using equipment and
procedures that will produce recommended moisture contents and densities throughout
the lift. It is recommended all fill material to placed on the site be compacted to at least
95 percent of Standard Proctor Density ASTM D698.
On -site clay soils should be compacted within a moisture content range of 2 percent
below, to 2 percent above optimum. Imported granular soils should be compacted within a
moisture range of 3 percent below to 3 percent above optimum unless modified by the
project geotechnical engineer.
Excavation and Trench Construction
Excavations into the on -site soils will encounter a variety of conditions. Excavations into
the clays can be expected to stand on relatively steep temporary slopes during
construction. However, caving soils and groundwater may also 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.
The soils to be penetrated by the proposed excavations may vary significantly across the
site. The preliminary soil classifications are based solely on the materials encountered in
widely spaced exploratory test borings. The contractor should verify that similar conditions
exist throughout the proposed area of excavation. If different subsurface conditions are
encountered at the time of construction, the actual conditions should be evaluated to
determine any excavation modifications necessary to maintain safe conditions.
As a safety measure, it is recommended that all vehicles and soil piles be kept to a
minimum lateral distance from the crest of the slope equal to no less than the slope height.
The exposed slope face should be protected against the elements.
15
Geotechnical Engineering Report
Proposed Car Wash Facility
S/E/C of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
1rerracnn
Exposed areas, which will receive fill, once properly cleared and benched where
necessary, should be scarified to a minimum depth of 12-inches, conditioned to near
optimum moisture content, and compacted.
It is anticipated that excavations for the proposed construction can be accomplished with
conventional earthmoving equipment.
Based upon the subsurface conditions determined from the geotechnical exploration, the
majority of the underlying subgrade soils exposed during construction are anticipated to be
relatively stable; however soft compressible and/or unstable areas will be encountered
during construction in close proximity to groundwater, or where the cohesive soils have a
high moisture content. The stability of the subgrade may be affected by precipitation,
repetitive construction traffic or other factors. If unstable conditions develop, workability
may be improved by scarifying and drying. Overexcavation of wet zones and replacement
with granular materials may be necessary. Use of lime, fly ash, kiln dust, cement or
geotextiles could also be considered as a stabilization technique. Laboratory evaluation is
recommended to determine the effect of chemical stabilization on subgrade soils prior to
construction. Lightweight excavation equipment may be required to reduce subgrade
pumping.
Subgrade Preparation
Subgrade soils beneath interior and exterior slabs should be scarified; moisture
conditioned and compacted to a minimum depth of 12-inches below proposed controlled
fill material. The moisture content and compaction of subgrade soils should be maintained
until slab or pavement construction.
Fill Materials and Placement
Approved imported materials may be used as fill material and are suitable for use as
compacted fill beneath interior or exterior floor slabs.
Imported soils (if required) should conform to the following:
Gradation
Percent finer by weight
(ASTM C136)
3"......................................................................................................... 100
No. 4 Sieve..................................................................................... 50-100
No. 200 Sieve.............................................................................. 35 (max)
14
Geotechnical Engineering Report lrerraron
Proposed Car Wash Facility
S/E/C of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
investment for pavements. Prior to implementing any maintenance, additional engineering
observation is recommended to determine the type and extent of preventive maintenance.
Site grading is generally accomplished early in the construction phase. However as construction
proceeds, the subgrade may be disturbed due to utility excavations, construction traffic,
desiccation, or rainfall. As a result, the pavement subgrade may not be suitable for pavement
construction and corrective action will be required. The subgrade should be carefully evaluated at
the time of pavement construction for signs of disturbance or excessive rutting. If disturbance has
occurred, pavement subgrade areas should be reworked, moisture conditioned, and properly
compacted to the recommendations in this report immediately prior to paving.
Please note that if during or after placement of the stabilization or initial lift of pavement, the area
is observed to be yielding under vehicle traffic or construction equipment, it is recommended that
Terracon be contacted for additional alternative methods of stabilization, or a change in the
pavement section.
Earthwork
General Considerations
The following presents recommendations for site preparation, excavation, subgrade
preparation and placement of engineered fills on the project.
All earthwork on the project should be observed and evaluated by Terracon. The
evaluation of earthwork should include observation and testing of engineered fill, subgrade
preparation, foundation bearing soils, and other geotechnical conditions exposed during
the construction of the project.
Site Preparation
Strip and remove any existing debris or other deleterious materials from proposed building
and pavement areas. All exposed surfaces should be free of mounds and depressions
that could prevent uniform compaction.
After the required overexcavation is performed, the site should be initially graded to create
a relatively level surface to receive fill, and to provide for a relatively uniform thickness of
fill beneath proposed building addition.
13
Geotechnical Engineering Report
Proposed Car Wash Facility
S/E/C of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
lrerrmon
base course. Aggregate base course should be placed in lifts not exceeding six inches and
should be compacted to a minimum of 95% Standard Proctor Density (ASTM D698).
HMA pavement should be composed of a mixture of aggregate, filler, binders, and additives, if
required, and approved bituminous material in accordance with the LCUASS Pavement Design
Criteria. The HMA should conform to an approved mix design stating the Hveem and/or
Superpave properties, optimum asphalt content, job mix formula and recommended mixing and
placing temperatures. Aggregate used in the HMA should meet particular gradations, such as the
Colorado Department of Transportation Grading S, SX or SG specifications. Mix designs should
be submitted prior to construction to verify their adequacy. Asphalt material should be placed in
maximum 3-inch lifts and should be compacted to a within a range of 92 to 96 % of Maximum
Theoretical Density.
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:
• Site grading at a minimum 2% grade away from the pavements;
• The subgrade and the pavement surface have a minimum % inch per foot slope to promote
proper surface drainage.
• Consider appropriate edge drainage and pavement under drain systems,
• 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 subgrade soils without the use of base
course materials.
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
12
Geotechnical Engineering Report
Proposed Car Wash Facility
S/E/C of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
lrerracon
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 alternatives for flexible and rigid pavements, summarized for each traffic area, are
as follows:
",; `
s
r
RECOMMENDED MINIMUM PAVEMENT KNESS "INCHES
THICt
4�
. t
�!
to n : `
Aggregate Base
,
Traffic Area '
Alte matrves
F
a HMA Surtace x
,a HMA Surtace
Class 5
Rr � AshµTreatedPo�and
F
,
r
n
,- �
Grading S or SX
Grading SG
{Course t
Y
n +;Sub Baser-
Cement
�-
Total
�iA
1.5
2.5
6.0
10.0
Automobile
B
3.5
6.0
12.0
21.5
Parking Areas
C —1
6.0
6.0
C — 2
12.0
5.5
17.5
(3) A
2.0
3.0
7.0
12.0
Heavy
B
1.5
2.5
6.0
12.0
22.0
Dutyrrruck
Traffic Areas
C —1
7.0
7.0
C — 2
12.0
6.0
18.0
(1) If the HMA surface course is to consist of Grading S, then the required minimum lift/thickness
placed should be 2-inches. If the HMA surface course is to consist of Grading SX, the
required minimum lift/thickness placed should be 1-1/2-inches.
(2) If fly ash is utilized for the on -site pavement improvement areas to mitigate the soft subgrade
materials, it is recommended that at least the upper 12-inches of the prepared subgrade be
treated with fly ash. Terracon is available to provide the required laboratory soil and fly ash
mix design as well as placement recommendations upon request.
(3) Alternative A assumes a minimum of 2-feet of approved moisture conditioned/non-expansive
fill material is positioned beneath the planned paved sections, after an approved proof -roll has
been completed.
Due to the properties of the existing cohesive on -site soils, full depth HMA pavement is not
recommended.
Each alternative should be investigated with respect to current material availability and economic
conditions. Aggregate base course (if used on the site) should consist of a blend of sand and
gravel, which meets strict specifications for quality and gradation. Use of materials meeting
Colorado Department of Transportation (CDOT) Class 5 or 6 specifications is recommended for
11
Geotechnical Engineering Report
Proposed Car Wash Facility
S/E/C of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
lferrecon
consolidometer apparatus and inundated after a predetermined load, (approximately 150 psf to
simulate the actual loading conditions experienced within an asphalt paved section underlain by
an aggregate base course), is placed. The swell index is the resulting amount of swell as a
percent of the sample's thickness after the inundation period.
The swell potential for the subgrade soils, (i.e. subsoil samples collected approximately 1-foot
below existing site grades in Test Boring No. 4), based on the LCUASS Pavement Design
laboratory testing procedures, resulted in swell index value of (+) 5.0 %. This value exceeds the
maximum 2 percent criteria established for determining if swell -mitigation procedures in the
pavement sections are required. Therefore, it will be necessary to mitigate the cohesive subgrade
soils prior to pavement operations due to swelling soils. Due to the relatively dry, stiff and swell
potential characteristics of the existing fill material it is recommended to remove the fill material to
the native subsoils below. The fill material is suitable for reuse provided the recommendations
contained in the Earthwork" section are followed. We provide herein, site -specific
recommendations for subgrade stabilization if necessary after proofrolling the subgrade section.
Stabilization may include incorporation of a chemical treatment such as kiln dust, and/or fly ash to
mitigate swell potential soils. An alternate would be to over -excavate and replace with approved
materials or provide 2-feet of non -expansive granular soils.
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.
If the fly ash section is selected, Terracon recommends incorporating approximately 12 percent 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. Based on
the subsurface conditions encountered at the site, and the laboratory test results, it is
recommended the on -site private drives and parking areas be designed using a minimum R-value
of 7.
Pavement design methods are intended to provide structural sections with adequate thickness
over a particular subgrade such that wheel loads are reduced to a level the subgrade can support.
The support characteristics of the subgrade for pavement design do not account for shrink/swell
movements of an expansive clay subgrade such as the soils encountered on this project. Thus,
the pavement may be adequate from a structural standpoint, yet still experience cracking and
10
Geotechnical Engineering Report lferracon
Proposed Car Wash Facility
S/E/C of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
• 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.
• A minimum 2-inch void space should be constructed above or below non -bearing
partition walls placed on slabs on grade. Special framing details should be
provided at doorjambs and frames within partition walls to avoid potential
distortion. Partition walls should be isolated from suspended ceilings.
• Interior trench backfill placed beneath slabs should be compacted in accordance
with recommended specifications outlined below.
• In areas subjected to normal, loading, a minimum 4-inch layer of clean -graded
gravel or aggregate base course should be placed beneath upper level interior
slabs.
• Floor slabs should not be constructed on frozen subgrade.
• Other design and construction considerations, as outlined in the ACI Design
Manual, Section 302.1 R are recommended.
Pavement Design and Construction
Based on the subsurface conditions encountered during the site exploration, it is our opinion the
proposed on -site pavement areas are feasible provided the following recommendations are
implemented. The subsoils encountered throughout the site are generally plastictcohesive soils
exhibiting low subgrade strength characteristics and low to high swell/expansive potential. This
report provides recommendations to help mitigate the effects of soil shrinkage and expansion.
Even if these recommendations are followed some pavement distress and exterior slab
movement should be anticipated.
To evaluate the existing on -site soils for use as subgrade material beneath on -site pavement
sections, we elected to use the design criteria established in the Larimer County Urban Area
Street Standards (LCUASS) Pavement Design document as a guideline. In the LCUASS
guidelines, undisturbed samples usually obtained directly from a ring barrel sampler, California
Barrel or a cylindrical Shelby Tube device are placed in a laboratory one-dimensional
S
Geotechnical Engineering Report
Proposed Car Wash Facility
S/E/C of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
lferrecon
The lateral earth pressures herein do not include any factor of safety and are not applicable for
submerged soils/hydrostatic loading. Additional recommendations may be necessary if
submerged conditions are to be included in the design.
Fill against grade beams and retaining walls should be compacted to densities specified in
Earthwork. Medium to high plasticity clay soils should not be used as backfill against retaining
walls. Compaction of each lift adjacent to walls should be accomplished with hand -operated
tampers or other lightweight compactors. Overcompaction may cause excessive lateral earth
pressures, which could result in wall movement.
Seismic Considerations
The project site is located in Seismic Risk Zone I of the Seismic Zone Map of the United States
as indicated by the 1997 Uniform Building Code. Based upon the nature of the subsurface
materials, Soil Profile Type "Sc" should be used for the design of structures for the proposed
project (1997 Uniform Building Code, Table No. 16-J). A site classification "C" should be used
for the design of structures for the proposed project (2003 International Building Code, Table
No. 1615.1.1).
Floor Slab Design and Consideration
Conventional -type slab -on -grade construction procedures are feasible for the site. As presented
on the enclosed boring logs and swell -consolidation test results low to high expansive soils are
present on this site. This report provides recommendations to help mitigate the effects of soil
shrinkage and settlement. However, even if these procedures are followed, some movement and
at least minor cracking in the structure's foundation and slabs should be anticipated. The severity
of cracking and other cosmetic damage such as uneven floor slabs will probably increase if any
modification of the site results in excessive wetting or drying of the compressible materials.
Eliminating the risk of movement and cosmetic distress may not be feasible, but it may be
possible to further reduce the risk of movement if significantly more expensive measures are used
during construction. Some of these options, such as the use of structural floors or mechanically
stabilizing the soft compressible materials are discussed in this report. We would be pleased to
discuss other construction alternatives with you upon request.
Additional floor slab design and construction recommendations for upper and lower level slabs
are as follows:
C
Geotechnical Engineering Report
Proposed Car Wash Facility
S/E/C of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
1rerracon
dead -load pressure will also reduce differential settlement between adjacent footings. Total
movement resulting from the assumed structural loads is estimated to be about 1-inch. Additional
foundation movements could occur if water from any source infiltrates the foundation soils;
therefore, it is imperative proper drainage should be provided and maintained in the final design
and during construction for each structure. if the subsoils become wetted below the proposed
structures, movement exceeding 1-inch is likely. If this type of movement can not be tolerated
and the subsurface soils become wetted, consideration should be given to an overexcavation and
replacement . procedure to minimize/reduce the swell potential. If this alternative is to be
considered additional recommendations can be provided upon request.
Final recommendations during 'open -hole" or foundation excavation observations may vary
depending upon conditions at that time, additional overlot grading procedures or design
elevations. Foundation excavations should be observed by the geotechnical engineer. If the soil
conditions encountered differ significantly from those presented in this report, supplemental
recommendations will be required. Foundation and walls should be reinforced as necessary to
reduce the potential for distress caused by differential foundation movement. The use of joints at
openings or other discontinuities in walls is recommended.
Lateral Earth Pressures
For soils above any free water surface, recommended equivalent fluid pressures for
unrestrained foundation elements are:
• Active:
Cohesive soil backfill (on -site clay soils).................................45 psf/ft
Cohesionless soil backfill (granular imported soils).................35 psf/ft
• Passive:
Cohesive soil backfill (on -site clay soils)...............................250 psf/ft
Cohesionless soil backfill (granular imported soils)...............350 psf/ft
• Adhesion at base of footing.....................................................500 psf
Where the design includes restrained elements, the following equivalent fluid pressures are
recommended:
At rest:
Cohesive soil backfill (on -site clay soils).................................60 psf/ft
Cohesionless soil backfill (granular imported soils).................50 psf/ft
7
Geotechnical Engineering Report 1irracon
Proposed Car Wash Facility
S/E/C of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
ENGINEERING ANALYSES AND RECOMMENDATIONS
Geotechnical Considerations
The site appears suitable for the proposed construction from a geotechnical engineering point of
view. It is important to establish and maintain good/positive surface drainage, especially in the
immediate area of the proposed building footprints during and after construction.
The following foundation system was evaluated for use on the site for the proposed addition:
• Conventional -type spread footings bearing on approved native subsoils, or engineered
fill material, which extends to the native, undisturbed subsoils below. Footings should
not be placed on the existing overlot fill material in its in -situ condition.
Conventional slab -on -grade construction procedures are considered acceptable for use, provided
the design and construction recommendations presented herein are followed. Consideration
should be given to installing a perimeter drainage system around the foundation areas discharging
into a sump pit or day lighting away from the buildings.
Foundation Systems — Conventional Type Spread Footings
Due to the anticipated loads, the type of construction proposed and the soil conditions
encountered within test borings analyzed to date, it is recommended the proposed building be
supported by the use a conventional type spread footing foundation systems bearing upon the
native subsoils or engineered controlled fill material which extends to the native subsoils below.
Due to the moderate swell potential of the existing on -site fill material and the uncontrolled
characteristics, it is recommended that all footings bear on the native undisturbed subsoils or on
engineered fill material, which extends to the native subsoils below. The on -site fill materials
suitable for reuse provided the recommendations contained in the Earthwork" section of this report
are followed.
Footings for the proposed buildings should be designed using a maximum net allowable bearing
pressure of 2,000 pounds per square foot (psf). In addition, all footings should be designed to
maintain a minimum dead load pressure of 500 psf. Exterior footings should be placed a
minimum of 30 inches below finished grade for frost protection and to provide confinement for the
bearing soils. Finished grade is the lowest adjacent grade for perimeter footings.
Footings should be proportioned to reduce differential foundation movement. Proportioning on
the basis of equal total movement is recommended; however, proportioning to relative constant
Geotechnical Engineering Report
Proposed Car Wash Facility
S/E/C of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
lferraran
Recommended Representative Swell Potential Descriptions and Corresponding
Slab Performance Risk Categories
J
Representative Percent Swell
Representative Percent,3well
r, Slab Performance Risk Category
� � �
j � P� 9' j
� '�(f 000 psf Surcharge) �
Low
0 to < 3
0 < 2
Moderate
3 to < 5
2 to < 4
High
5to<8
4to<6
Very High
> 8
> 6
Based on the laboratory test results, the samples of the native cohesive material analyzed for this
project generally were within the low range, however the overlot grading fill material exhibited high
swell potential. Due to the potential movement to occur if the underlying, relatively dry to moist,
stiff cohesive foundation bearing strata increases in moisture content we recommend positive
drainage be maintained prior to during and post construction to reduce the potential for surface
water infiltration from impacting the on -site cohesive soils.
Groundwater Conditions
Groundwater was not encountered during the initial field exploration and when checked several
days after drilling dry cave in (DCI) measurements were recorded at approximate depths of 6 to
10 % -feet below site grades. These observations represent groundwater conditions at the time of
the field exploration, and may not be indicative of other times, or at other locations. Groundwater
levels can be expected to fluctuate with varying seasonal and weather conditions and the flow
levels of the nearby Poudre River.
Based upon review of U.S. Geological Survey maps ('Hillier, et al, 1983), regional groundwater is
expected to be encountered in unconsolidated alluvial deposits on the site, at depths ranging from
10 to 20-feet below the existing ground surface at the project site.
1 Hillier, Donald E.; Schneider, Paul A., Jr.; and Hutchinson, E. Carter, 1983, Depth to Water Table (1979) in the Boulder -
Fort Collins -Greeley Area, Front Range Urban Corridor, Colorado, United States Geological Survey, Map 1-855-I.
5
Geotechnical Engineering Report lrerracon
Proposed Car Wash Facility
S/E/C of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
Field and Laboratory Test Results
Field and laboratory test results indicate the overlot fill material exhibits moderate to high swell
potential when inundated with water and low to moderate bearing capabilities. However at this
time, we do not possess adequate information regarding whether the fill was placed under
controlled conditions to warrant placement of footings, floor slabs, or pavement sections on the fill
material encountered without additional testing. The native cohesive soils and clayey sand soils
exhibited low swell potential when inundated with water and low to moderate bearing capabilities.
Swell — Consolidation Test Results
The swell -consolidation test is commonly performed to evaluate the swell or collapse potential of
soils or bedrock for determining foundation, floor slab and pavement design criteria, as well as the
rate of consolidation. In this test, relatively undisturbed samples obtained directly from the ring
barrel sampler or Shelby Tube sampling devices are placed in a laboratory apparatus and
inundated with water under a predetermined load. The swell -index is the resulting amount of swell
or collapse as a percent of the sample's thickness after the inundation period. Samples obtained
at the 0.5 to 1-foot intervals for pavement analyses are typically pre -loaded and inundated with
water at approximately 150 pounds per square foot (psf) to simulate actual pavement loading
conditions. Samples obtained at the 3 to 4-foot intervals are generally pre -loaded and inundated
with water at approximately 500 pounds per square foot (psf), while samples obtained at the 7 to
9-foot intervals are pre -loaded and inundated with water at approximately 1,000 psf to simulate
the overburden soil pressures. After the inundation period additional incremental loads are applied
to evaluate the rate of consolidation.
For this assessment, we conducted 3 swell -consolidation tests at various intervals/depths
throughout the site. The swell index values for the soil samples tested at the 150 psf, 500 psf and
1,000-psf inundation pressures revealed low to moderate swell characteristics on the order of (+)
1.2 to (+) 5.0 %.
Colorado Association of Geotechnical Engineers (CAGE) uses the following information to provide
uniformity in terminology between geotechnical engineers to provide a relative. correlation of slab
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.
4
Geotechnical Engineering Report lrerracon
Proposed Car Wash Facility
S/E/C of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
Laboratory tests were conducted on selected soil and bedrock samples and are presented in
Appendix B. The test results were used for the geotechnical engineering analyses, and the
development of foundation and earthwork recommendations. All laboratory tests were performed
in general accordance with the applicable local or other accepted standards. Selected soil and
bedrock samples were tested for the following engineering properties:
• Water Content • Atterberg Limits and % (-) No. 200 Sieve
• Dry Density • Swell — Consolidation
• Grain Size Analysis
SITE CONDITIONS
The site for the proposed carwash facility is presently a vacant tract of land located at the
southeast comer of Mulberry Street and Lemay Avenue. The property is sparsely vegetated with
native grass and weeds, along with a row of deciduous trees running parallel with Mulberry Street
on the south side of the lot near the Poudre River. The parcel is relatively flat, exhibiting positive
surface drainage in the south and east directions toward the Poudre River. A minor drainage
swale runs along the north side of the site, running parallel with Mulberry Street. Mulberry Street
borders the north side of the parcel and Lemay Avenue borders the site to the west. Existing
single story commercial buildings border the east side of the lot and the Poudre River boarders
the south side.
SUBSURFACE CONDITIONS
Soil Conditions
The subsurface soils at the site consisted of an approximate 2 to 3 feet of overlot grading fill
material underlain by native sandy lean clay and/or clayey sand, which extended to the granular
stratum below. Silty sand with gravel was encountered at an approximate depth of 3 to 7-feet
below existing site grades and extended to the depths explored, approximately 15-feet below
existing site grades. The stratification boundaries shown on the enclosed boring logs represent
the approximate locations of changes in soil types; in -situ, the transition of materials may be
gradual.
OR
Geotechnical Engineering Report lferramon
Proposed Car Wash Facility
S/E/C of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
SITE EXPLORATION
The scope of the services performed for this project included a site reconnaissance by an
engineering geologist, a subsurface exploration program, laboratory testing and engineering
analyses.
Field Exploration
For this study a total of four (4) test borings were drilled on July 21, 2006, at the locations shown
on the Test Boring Location Diagram, Figure 1 included in Appendix A. The test borings were
drilled to approximate depths of 10 to 15-feet below existing site grades and were advanced with a
truck -mounted drilling rig, utilizing 4-inch diameter solid stem augers.
The borings were located in the field by using a hand held GPS unit referenced to existing site
features. Ground surface elevations at each boring location were determined by the use of an
engineer's level and referenced to a temporary benchmark (TBM), which consisted of a surveyors
control point (CP) situated near the northwest comer of the site and using an assumed elevation
of 100 feet. The accuracy of boring locations and elevations should only be assumed to the level
implied by the methods used.
Lithologic logs of each boring were recorded by the engineering geologist during the drilling
operations. At selected intervals, samples of the subsurface materials were taken by means of
driving split -spoon and ring barrel samplers.
Penetration resistance measurements were obtained by driving the split -spoon (SS) and ring
barrel (RS) into the subsurface materials with a 140-pound hammer falling 30 inches. The
penetration resistance value is a useful index in estimating the consistency, relative density or
hardness of the materials encountered.
Laboratory Testing
All samples retrieved during the field exploration were returned to the laboratory for observation by
the project geotechnical engineer and were classified in general accordance with the Unified Soil
Classification System described in Appendix C. At that time, the field descriptions were confirmed
or modified as necessary and an applicable laboratory testing program was formulated to
determine engineering properties of the subsurface materials. Boring logs were prepared and are
presented in Appendix A.
9
GEOTECHNICAL ENGINEERING REPORT
PROPOSED CARWASH FACILITY — 2'/2 - ACRE PARCEL
SOUTHEAST CORNER OF MULBERRY STREET AND LEMAY AVENUE
FORT COLLINS, COLORADO
TERRACON PROJECT NO.20065109
AUGUST 15, 2006
INTRODUCTION
This report contains the results of our geotechnical engineering exploration for the proposed
carwash facility to be located at a vacant tract of land situated the southeast corner of Mulberry
Street and Lemay Avenue in Fort Collins, Colorado. The site is located in the Southwest % of
Section 7, Township 7 North, Range 68 West of the 6th Principal Meridian, Larimer County, Fort
Collins, Colorado.
The purpose of these services is to provide information and geotechnical engineering
recommendations relative to:
• subsurface soil conditions
• groundwater conditions
• foundation design and construction
• floor slab design and construction
• lateral earth pressures
• pavement design and construction
• earthwork
• drainage
The recommendations contained in this report are based upon the results of field and laboratory
testing, engineering analyses, and experience with similar soil conditions, structures and our
understanding of the proposed project.
PROPOSED CONSTRUCTION
The project as we understand it is to construct a single -story slab on grade carwash building
ranging in plan dimensions from approximately 3,500 square feet to 4,000 square feet. The
building will be constructed with load bearing masonry walls and steel framed members having
assumed wall and column loads on the order of 1 to 4 kips per lineal foot and 15 to 150 kips,
respectively. The project also will have associated parking and driveway areas as depicted on
the enclosed site plan. We assume that finished floor elevation will at or slightly above existing
site grades.
TABLE OF CONTENTS
Page No.
Letterof Transmittal.....................................................................................................I
INTRODUCTION............................................................................................................................. 1
PROPOSEDCONSTRUCTION..................................................................................................... 1
SITEEXPLORATION..................................................................................................................... 2
FieldExploration................................................................................................................... 2
LaboratoryTesting................................................................................................................ 2
SITECONDITIONS......................................................................................................................... 3
SUBSURFACECONDITIONS....................................................................................................... 3
SoilConditions...................................................................................................................... 3
Field and Laboratory Test Results........................................................................................ 4
Swell - Consolidation Test Results....................................................................................... 4
GroundwaterConditions....................................................................................................... 5
ENGINEERING ANALYSES AND RECOMMENDATIONS.......................................................... 6
Geotechnical Considerations................................................................................................
6
Foundation Systems - Conventional Type Spread Footings ................................................
6
Lateral Earth Pressures........................................................................................................
8
SeismicConsiderations........................................................................................................
8
Floor Slab Design and Consideration...................................................................................
8
Pavement Design and Construction.....................................................................................
9
Earthwork..............................................................................................................................
9
General Considerations............................................................................................
13
SitePreparation........................................................................................................
13
SubgradePreparation...............................................................................................
14
Fill Materials and Placement.....................................................................................
14
Excavation and Trench Construction........................................................................
15
Additional Design and Construction Considerations..........................................................
16
Exterior Slab Design and Construction.....................................................................
16
Underground Utility Systems....................................................................................
16
SurfaceDrainage.......................................................................................................
17
GENERALCOMMENTS.............................................................................................................. 17
APPENDIX A
Boring Location Diagram
Logs of Borings
APPENDIX B
Laboratory Test Results
APPENDIX C
General Notes
Geotechnical Engineering Report
Proposed Car Wash Facility
S/E/C of Mulberry Street and Lemay Avenue
Fort Collins, Larimer County, Colorado
Project No. 20065109
1rerrecon
We appreciate being of service to you in the geotechnical engineering phase of this project, and
are prepared to assist you during the construction phases as well. If you have any questions
concerning this report or any of our testing, inspection, design and consulting services please feel
free to contact us.
Sincerely,
TERRACON
Christopher . Gemperline,
Engineeri g Geologist
Copies to: Addressee (4)
David A. Richer, P.E.
Geotechnical Enqinei
iger
August 15, 2006
Mr. John Agnew
P.O. Box 827
Frisco, Colorado 80443
Re: Geotechnical Engineering Report
Proposed Car Wash Facility — 2 % -Acre Parcel
Southeast Corner of Mulberry Street and Lemay Avenue
Fort Collins, Colorado
Terracon Project No. 20065/09
Irerracon
Consulting Engineers & Scientists
Terracon Consultants, Inc.
301 North Howes
Fort Collins, Colorado 80521
Phone 970.484.0359
Fax 970.484.0454
www.terracon.com
Terracon has completed a geotechnical engineering exploration for the proposed car wash facility
and associated pavement areas to be located on vacant tract of land situated at southwest corner
of Mulberry Street and Lemay Avenue in Fort Collins, Colorado. This study was performed in
general accordance with Terracon's Proposal No. D2006239, dated June 30, 2006.
The results of our recenf engineering study for the proposed car wash facility including the boring
location diagram, laboratory test results, test boring records, and geotechnical recommendations
needed to aid in the design and construction of foundations, floor slabs, on -site pavement areas,
and other earth connected phases of this project are attached.
Test Boring Nos. 1 through 3 were drilled within the proposed building footprint, while Boring No. 4
was drilled within the proposed pavement area to be constructed north and east of the carwash
building. The subsurface soils at the site consisted of an approximate 2 to 3 feet of overlot grading
fill material underlain by native sandy lean clay and/or clayey sand, which extended to the granular
stratum below. Silty sand with gravel was encountered at an approximate depth of 3 to 7-feet
below existing site grades and extended to the depths explored, approximately 15-feet below
existing site grades. Groundwater was not encountered during the initial field exploration and
when checked several days after drilling dry cave in (DCI) measurements were recorded at
approximate depths of 6 to 10'/z -feet below site grades.
The results of our field exploration and laboratory testing completed for this study indicated the
overlot fill material exhibits low to moderate swell potential when inundated with water and low to
moderate bearing capabilities. However at this time, we do not possess adequate information
regarding whether the fill was placed under controlled conditions to warrant placement of footings,
floor slabs, or pavement sections on the fill material encountered without additional testing. The
native cohesive soils and clayey sand soils exhibited low swell potential when inundated with
water and low to moderate bearing capabilities. Based on the subsurface conditions encountered,
the proposed car wash building could be supported by conventional spread footings bearing on
the native subsoils, or on approved engineered fill material, which extends to the undisturbed
subsoils below. .
Conventional floor slab construction is feasible for the site provided the recommendations
contained herein are followed. Other design and construction recommendations based upon
geotechnical conditions are presented in the report.
Delivering Success for Clients and Employees Since 1965
More Than 70 Offices Nationwide
GEOTECHNICAL ENGINEERING REPORT
PROPOSED CARWASH FACILITY — 2'/z -ACRE PARCEL
SOUTHEAST CORNER OF MULBERRY STREET AND LEMAY AVENUE
FORT COLLINS, COLORADO
TERRACON PROJECT NO.20065109
AUGUST 15, 2006
Prepared for:
MR JOHN AGNEW
P.O.BOX 827
FRISCO, COLORADO 80443
Prepared by:
Terracon
301 North Howes Street
Fort Collins, Colorado 80521
Irerracon