HomeMy WebLinkAboutSTONERIDGE PUD, THIRD FILING PRELIMINARY - 21 92F - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTGEOTECHNICAL ENGINEERING REPORT
PROPOSED PAVEMENT
STONE RIDGE FILING THREE
FORT COLLINS, COLORADO
ELI PROJECT NO. 20935273
Prepared for:
MR. LESTER KAPLAN
1060 SAILORS REEF
FORT COLLINS, COLORADO 80525
Empire Laboratories, Inc.
A Division of The Terracon Companies. Inc.
Mr. Lester Kaplan
ELI Project No. 20935273
Local drainage characteristics of proposed pavements areas are considered to vary from fair to
good depending upon location on the site. For purposes of this design analysis, fair drainage
characteristics are considered to control the design. These characteristics, coupled with the
approximate duration of saturated subgrade conditions, results in a design drainage coefficient of
1.0 when applying the AASHTO criteria for design.
For flexible pavement design of low traffic volume streets, a terminal serviceability index of 2.0
was utilized along with an inherit reliability of 70%. Using the correlated design R-value,
appropriate ESAL/day, environmental criteria and other factors, the structural numbers (SN) of the
pavement sections were determined on the basis of the 1986 AASHTO design equation.
In addition to the flexible pavement design analyses, a rigid pavement design analysis was
completed, based upon AASHTO design procedures. Rigid pavement design is based on an
evaluation of the Modulus of Subgrade Reaction of the soils (K-Value), the Modulus of Rupture of
the concrete, and other factors previously outlined. The design K-value of 100 for the subgrade
soil was determined by correlation to the laboratory test results. A Modulus of Rupture of
650 psi (working stress 488 psi) was used for pavement concrete. The rigid pavement thicknesses
for each traffic category were determined on the basis of the AASHTO design equation.
Recommended alternatives for flexible and rigid pavements, summarized for each traffic area, are
as follows:
Recommended Pavement Section Thickness
(Inches)
Traffic Area
Alterna-
tive
Asphalt
Aggregate
Plant Mix
Portland
Concrete
Base
Bituminous
I
Cement
TOTAL
Surface
Course
Base Course
Concrete
Light Traffic,
A
3"
7"
10"
B
2"
3'/:"
5Yz"
Residential
Streets and
Cut -De -Sacs
C
6"
6"
Each alternative should be investigated with respect to current material availability and economic
conditions. In view of the subgrade soil conditions and projected traffic, either full -depth asphalt
or rigid concrete pavement sections should be considered in areas of main traffic corridors, drive
bays or truck access. Rigid concrete pavement is recommended at the location of dumpsters
where trash trucks will, park and load.
5
Mr. Lester Kaplan
ELI Project No. 20935273
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 Class 5 or 6 specifications is recommended.
Aggregate base course should be placed in lifts not exceeding six inches and should be compacted
to a minimum.of 95% StandardProctor density (ASTM D-698), within a moisture content range
of 2 percent below, to 2 percent above optimum.
Asphalt concrete should be obtained from an approved mix design stating the Marshall or Hveem
properties, optimum asphalt content, job mix formula, and recommended mixing and placing
temperatures. Aggregate used in asphalt concrete should meet a particular gradation. Use of
materials meeting Colorado Department of Transportation Grading C or CX specifications is
recommended. The mix design should be submitted prior to construction to verify its adequacy.
The asphalt material should be placed in maximum 3-inch lifts, and should be compacted to a
minimum of 95% Hveem density (ASTM D-1561).
Where rigid pavements are used the concrete should be obtained from an approved mix design
with the following minimum properties:
• Compressive Strength @ 28 days ................... 3750 psi minimum
• 'Modulus of Rupture @ 28 days ..................... 650 psi minimum
• Strength Requirements ............................... ASTM C-94
• Minimum Cement Content .......................... 5.5 sacks/cu.yd.
• Cement Type .................................... Type I Portland
o Entrained Air Content ................................. 6% + 2%
• Concrete Aggregate ................ ASTM C-33 and CDOT Section 703
• Aggregate Size ................................. 1 inch maximum
• Maximum Water Content ....................... 0.49 lb/lb of cement
0 Maximum Allowable Slump ........................... .. 4 inches
Concrete should be deposited by truck mixers or agitators and placed a maximum of 90 minutes
from the time the water is added to the mix. Other specifications outlined by the Colorado
Department of Transportation should be followed.
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 and should be spaced (in feet), at roughly twice the slab thickness (in
inches), on center in either direction. Sawed joints should be cut within 24-hours of concrete
placement, and should be a minimum depth of 25% of slab thickness plus 1/4 inch. All joints
H.
Mr. Lester Kaplan
ELI Project No. 20935273
should be sealed to prevent entry of foreign material and dowelled where necessary for load
transfer. Where dowels cannot be used at joints accessible to wheel loads,, pavement thickness
should be increased by 25 percent at the joints and tapered to regular thickness in 5 feet.
Future performance of pavements constructed on the clay soils at this site will be dependent upon
several factors, including:
• Maintaining stable moisture content of the subgrade soils; and,
• Providing for a planned program of preventative maintenance.
Since the clay soils on the site have shrink/swell characteristics, pavements could crack in the
future primarily because of expansion of the soils when subjected to an increase in moisture
content to the subgrade. The cracking, while not desirable, does not necessarily constitute
structural failure of the pavement.
The performance of all pavements, but in particular the recommended asphalt sections, can be
enhanced by minimizing excess moisture which can reach the subgrade soils. The following
recommendations should be considered at minimum:
• Site grading at a minimum 2% grade away from the pavements;
• Compaction of any utility trenches for landscaped areas to the same criteria as the
pavement subgrade;
• Sealing all landscaped areas in, or adjacent to pavements.to minimize or prevent
moisture migration to subgrade soils;
• Placing compacted 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.
Preventative maintenance should be planned and provided for through an on -going pavement
management program in order to enhance future pavement performance. Preventative
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 sealing and patching)
and global maintenance (e.g. surface sealing). Preventative maintenance is usually the first priority
7
Mr. Lester Kaplan
ELI Project No. 20935273
when implementing a planned pavement maintenance program and provides the highest return on
investment for pavements.
Recommended preventative maintenance policies for asphalt and jointed concrete pavements,
based upon type and severity of distress, are provided in Appendix D. Prior to implementing any
maintenance, additional engineering observation is recommended to determine the type, and
extent of preventative maintenance.
Earthwork:
• General Considerations: The conclusions contained in this report for the proposed
construction are contingent upon compliance with recommendations presented in this
section.
Although fills or underground facilities; such as septic. tanks, cesspools, basements, or
utilities, were not observed during site reconnaissance, such features might be encountered
during construction.
• Site Clearing:
1. Strip and remove existing vegetation, debris, and other deleterious materials from
proposed building and pavement areas. All exposed surfaces should be free of
mounds and depressions which could prevent uniform compaction.
2. If unexpected fills or underground facilities are encountered during site clearing,
such features should be removed, the excavation thoroughly cleaned and backfilled.
All excavations should be observed by the geotechnical engineer prior to backfill
placement.
3. Stripped materials consisting of organic materials should be wasted from the site,
or used to revegetate exposed slopes after completion of grading operations. If it
is necessary to dispose of organic materials on -site, they should be placed in non-
structural areas, and in fill sections not exceeding 5 feet in height.
4. 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
structures.
N.
Mr. Lester Kaplan
ELI Project No. 20935273
5. All exposed areas which will receive fill, once properly cleared and benched where
necessary, should be scarified to a minimum depth of eight inches, conditioned to
near optimum moisture content, and compacted.
• Excavation:
1. It is anticipated that excavations for the proposed construction can be accomplished
with conventional eartlimoving equipment.
2. Depending upon depth of excavation and seasonal conditions, groundwater may be
encountered in excavations on the site. Pumping from sumps may be utilized to
control water within excavations. Well points may be required for significant
groundwater flow, or where excavations penetrate groundwater to a significant
depth.
• ,Pavement Subwade Preparation:.• The subgrade should be scarified, moistened as required,
..and rec.ompacted fora minimun7.depth of 8 inches prior to placement of fill and pavement
materials.
1. Due to the plastic nature of the subsoils, the need for subgrade stabilization is
anticipated. On -site clay soils may pump or become unstable or unworkable at high
water contents. 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. Adequate laboratory testing should be
performed to evaluate the effectiveness of each chosen method of stabilization.,
Lightweight excavation equipment may be required to reduce subgrade pumping.
• Fill Materials:
1. Clean on -site soils or approved imported materials may be used as fill material for
the following:
• general site grading • pavement areas
2. Frozen soils should not be used as fill or backfill.
N
• Mr. Lester Kaplan
ELI Project No. 20935273
3. Imported soils (if required) should conform to the following:
O Gradation (ASTM C136):
percent finer by weight
6.. .............................................. 100
3"........................................... 70-100
No. 4 Sieve ........ 50-100
No. 200 Sieve .................................. 35 (max)
• Liquid Limit .................................. 35 (max)
• Plasticity Index .................................. 15 (max)
O Minimum "R"Value.................................... 7
4. Aggregate base should conform to Colorado Department of Transportation Class 5
or 6 specifications.
• Placement and Compaction:
1. Place and compact fill in horizontal lifts, using equipment and procedures that will
produce recommended moisture contents and densities throughout the lift.
2. Uncompacted fill lifts should not exceed 10 inches loose thickness.
- 3. No fill should be placed over frozen ground.
4. Materials should be compacted to the following:
Material
Minimum Percent
Compaction (ASTM D698)
On -site soils:
Beneath pavements ................................... 95
Imported fill:
Beneath pavements ................................... 95
Miscellaneous backfill....................................... 90
10
Mr.. Lester Kaplan
ELI Project No. 20935273
5. On -site clay soils should be compacted within a moisture content range of 2 percent
below optimum moisture to 2 percent above optimum. Imported granular soils
should be compacted within a moisture range of 2. percent .below to 2 percent
above optimum.
Compliance: Recommendations for pavement elements supported on compacted fills or
prepared subgrade depend upon compliance with "Earthwork" recommendations. To
assess compliance, observation and testing should be performed under the direction of the
geotechnical engineer.
GENERAL COMMENTS
It is recommended that the Geotechnical Engineer be retained to provide a general review of final
design plans and specifications in order that grading and pavement recommendations may be
interpreted and implemented. In the event that any changes of the proposed project are planned,
the conclusions and recommendations contained in this report should be reviewed and the report
modified or supplemented as necessary.
The Geotechnical Engineer should also be retained to provide services during excavation, grading,
pavement and construction phases of the work. Construction testing of fill placed on the site is
considered part of continuing geotechnical engineering service for the project. Field and laboratory
testing of concrete and asphalt should be performed to determine whether applicable requirements
have been met. It would be logical for Empire Laboratories, Inc. to provide these services since
we are most qualified to determine consistency of field conditions with those data used in our.
analyses.
The analyses and recommendations in this report are based in part upon data obtained from the
field exploration. The nature and extent of variations beyond the location of test borings may not
become evident until construction. If variations then appear evident, it may be necessary to
reevaluate the recommendations of this report.
Our professional services were performed using that degree of care and skill ordinarily exercised,
under similar circumstances, by reputable geotechnical engineers practicing in this or similar
localities. No warranty, express or implied, is made. We prepared the report as an aid in design
of the proposed project. This report is not a bidding document. Any contractor reviewing this
11
• Mr. Lester Kaplan
ELI Project No. 20935273
report must draw his own conclusions regarding site conditions and specific construction
techniques to be used on this project.
This report is for the exclusive purpose of providing geotechnical engineering and/or testing
information and recommendations. The scope of services for this project does not include, either
specifically or by implication, any environmental assessment. of the site or identification of
contaminated or hazardous materials or conditions. If the owner is concerned about the potential
for such contamination, other studies should be undertaken. We are available to discuss the scope
of such studies with you.
12
..LI r 25Z75
_.1c70�:d i Groi
Empire Laboratories, Inc.
A Division of The Terracon Companies, Inc.
LOG OF BOPJNG NO. 1
page 1 of 1
CLIENT
ARCHITECT/ENGINEER
Lester Kaplan
RBD Inc.
SITE
PROJECT
Fort Collins, Colorado
Stone Ridge Fi ing Three
SAMPLES
TESTS
g
>
o
CD
0
o
J
U_
>-
W
W
W
Z S
x H
>-
Ir
z\
ce
z
HH-
W n-
HDESCRIPTION
=
S
N
W
�
I co
H
0
ZZ
�Fy-J
(L
H--
O:
(A
U
m
E
W
a-
O
U
3
FO
(A
. H
}LL
O W
UQ:LLL
W H n.
F£\
W
(A
O
>-
W
D-J
O
.E
D:U
ZH(A
hHJ
O
O
7
Z
H-
0:
Nm
❑C.
O(n0-
QJJ
0.5 6" TOPSOIL
1
SS
6"
5
16.1
30/17/13
CL
PA
LEAN CLAY WITH SAND
Brown, moist, medium
3.0
7.
CL
2
SS
12"
6
11.2
5
PA
SANDY LEAN CLAY
WITH GRAVEL
Red, moist to wet, medium
8.0
POORLY GRADED GRAVEL
GP
3
SS
11"
50111
1.3
WITH SAND AND CLAY
Brown, dry to wet
10
PA
Dense to very dense
4
SS
12"
41
16.5
15.0
15
BOTTOM OF BORING
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS
Empire Laboratories
BORING STARTED 10-26-93
WL
Q W.D.IT
13,8" A.B.
BORING COMPLETED 10-26-93
iNTone
Incorporated
Division of Terracon
WL
RIG CD1E-55
FOREMAN TK
WL
Checked 24 Hrs. A.B.
APPROVED NTRS
JOB k 20935273
November 10, 1993
Mr. Lester Kaplan
1060 Sailors Reef
Fort Collins, Colorado 80525
Re: Geotechnical Engineering Report, Proposed Pavement
Stone Ridge Filing Three
Fort Collins, Colorado
ELI Project No. 20935273
Empire Laboratories, Inc. (ELI) has completed a geotechnical engineering exploration for the
proposed pavement to be located in Stone Ridge Filing Three. This study was performed in
general accordance with our proposal number D2093155 dated October 14, 1993.
The results of our engineering study, including the boring location diagram, laboratory test results,
test boring records, and the geotechnical recommendations needed to aid in the design and
construction of foundations and other earth connected phases of this project are attached.
The subsurface exploration indicated soil conditions which are typical of soils commonly found in
the southeast portion of the Fort Collins area. The subsurface soils at the site consisted of lean
clay with sand underlain by sandy lean clay and poorly graded gravel with sand and clay. The
information obtained by the results of field exploration and laboratory testing completed for this
study indicates that the soils at the site are plastic and have low subgrade strength characteristics.
Based on the geotechnical engineering analyses, subsurface exploration and laboratory test results,
we recommend that the proposed pavement consist of (1) asphalt concrete underlain by crushed
aggregate base course, (2) asphalt concrete underlain by plant mix bituminous base course or (3)
nonreinforced concrete pavement. Due to the plastic nature of the subsoil subgrade, stabilization
may be required.
Other design and construction details, based upon geotechnical conditions, are presented in the
report.
r-I
LOG OF BORING NO. 2
Page 1 of 1
CLIENT
ARCHITECT/ENGINEER
Lester Kaplan
RBD Inc.
SITE
PROJECT
Fort Collins, Colorado
Stone Ride Filing Three
SAMPLES
TESTS
�
�
F
o
ca
0
o
0
W
Z
U-
E
>-
W
N
2
DESCRIPTION
N
W
Z\
�
W
LLLD
H
2
x
m
O
3
OW
0_
F_
O.
W
U
E
W
a
U
F-O
CA
H
>_IL
UCr- LL
LD
W
fn
>
>-
W
D-J
O
frU
ZF_cn
L7
O
O
Z
F-
C
W0
E
Od
MNIL
',." �
0.5 6" TOPSOIL
1
SS
6"
6
20.7
PA
T_.R_AN CLAY WITH SAND _
Brown, moist, soft to medium
CL
2
ST
12"
18.4
103 14110
3
SS
12"
2
20.3
5
PA
6.0
SANDY LEAN CLAY_
WITH GRAVEL
CL
4
SS
12"
4
18.0
Red, moist to wet, medium
PA
10
_
Z
Q
5
SS
12"
5
21.2
15.0
IS
BOTTOM OF BORING
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS
BORING STARTED 10-26-93
Empire Laboratories
wL
g 131211 W.D.
IT 12'9'1 A.B.
BORING COMPLETED 10-26-93
Incorporated
Division of Termcon
RL
RIG CME-55
FOREMAN TIC
wL
Checked 24 Hn. A.B.
APPROVED NRS
JOB k 20935273
LOG OF BORING NO. 3
Page 1 of i
CLIENT
ARCHITECT/ENGINEER
Lester Kaplan
RBD Inc.
SITE
PROJECT
Fort Collins, Colorado
Stone Rid a Filing Three
SAMPLES
TESTS
F_
o
0
r,
o
J
DESCRIPTION
}
W
Z\
W
z
H�
w a
H
=
2
V7
W
�
10
1-
p
Zz
yJ
=F-
a
cc
-
H-
O-
to
U
no
E
W
O-
O
U
3
FO
to
H
YLL
O W
U�LL
W HO.
HZ\
W
W
0
>
>-
W
O_J
O
O:U
ZF-(A.
FHJ
L
O
7
Z
F-
W
wo
S
oa
�(na.
¢JJ
0.5 6"GRAVEL BASE COURSE
1.0 FILL Lean clay with sand
Brown, moist
PA
34/19/15
WITH SAND
1
SS
12"
4
17.6
LEAN CLAY
Brown, moist to wet, medium
PA
CL
2
SS
12"
6
15.4
5
PA
6.0
fF
3
ST
20.1
105
3140
"
SANDY LEAN CLAY
CL
4
SS
12"
6
21.1
WITH GRAVEL
Red, moist to wet, medium
PA
10
5
SS
12"
4
16.7
15.0
15
BOTTOM OF BORING
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS
BORING STARTED 10-26-93
Empire Laboratories
Incorporated
Division of Terracon
WT-
g 12'6" W.D.
12'2" A.B.
BORING COMPLETED 10-26-93
WL
RIG CME-55
FOREMAN TK
WL
Checked 24 Hrs. A.B.
APPROVED NRS
JOB q 20935273
LOG OF BORING NO. 4
Page 1 of 1
CLIENT
ARCHITECT/ENGINEER
Lester Kaplan
RBD Inc..
SITE
PROJECT
Fort Collins, Colorado
Stone Rid a Filing Three
SAMPLES
TESTS
g
\
>-
0
c)
DESCRIPTION
r
W
z�
W
z
HI—
<r
a
U
z
0-
U
F- o
H
O LL,
v W U.
o�F_crn
z
oEo0osa
c�a
un
n.
c
0.5 6" TOPSOIL
1
SS
6"
7
17.8
PA
LEAN CLAY WITH SAND
Brown, moist, soft to medium
CL
2
ST
12"
22.2
99
2210
3
SS
12"
2
24.9
5
PA
7.0
SANDY LEAN CLAY
CL
4
SS
12"
3
17.0
Brown, moist to wet, medium
PA
10
1
Q
5
SS
12"
7
18.3
-
15.0
15
BOTTOM OF BORING
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS
BORING STARTED 10-26-93
Empire Laboratories
WL
g 1490" W.D.
= 12'0" A.B.
BORING COMPLETED 10-26-93
Incorporated
Division of Terracon
WI.
RIG CME-J5
FOREMAN TK
Checked 24 Hrs. A.B.
APPROVED NRS
JOB q 20935273
LOG OF BORING NO. 5
page 1 of 1
CLIENT
ARCHITECT,'E.NGINEER
Lester Kaplan
RBD Ine.
SITE
PROJECT
Fort Collins, Colorado
Stone Ridge Filing Three
SAMPLES
TESTS
r
—1
O
U.
r_
>-
U.
W
Ln
z S
DESCRIPTION
y
w
z�
�
w
U-0
H
W
H
m
O
3
N.
O
OW
a.a.
to
W
n.
U
E
0-
L)
F O
- H
r W
U C LL
W
(n
:3>-
W
G.J
O
CU
ZF-fA
LD
c
M
z
C
vIm
r_
oa
:Dcno.
A A
0.5 6" TOPSOIL
1
SS
6"
7
21.3
PA
LEAN CLAY WITH SAND
Brown, moist, soft
CL
2
SS
12"
3
122.0
5
PA
7.0
3
ST
12"
19.1
100
1680
SANDY LEAN CLAY
CL
4
SS
12"
1
22.4
Brown, moist to wet
Very soft to medium
PA
10
t
Q
5
SS
12"
5
20.6
15.0
15
BOTTOM OF BORING
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS
Empire Laboratories
BORING STARTED 10-26-93
wL
11w.D.
g 1398
Y 13'r A.B.
BORING COMPLETED_ 10-26-93
Incorporated
W,
RIG CNIE-55
FGREI.uN TK
Division of Terracon
wL
Checked 24 Hrs. A.B.
APPROVED NRS
JOB p 20935273
11
LOG OF BORING NO. 6
Page 1 of 1
CLIENT
ARCHIT'ECTIEN GINEER
Lester Kaplan
RBD Inc.
SITE
PROTECT
Fort Collins, Colorado
Stone Ridge Filing Three
SAMPLES
TESTS
O
OUL
}
�
U
DESCRIPTION
Z\
ex
z
HI=—
w a-
I..F
_
2
fJ7
C=
W
W
=0
I (n
O
F-.
W
O
LL O
ZZ
ra W \
CF-J
Q
F-
0.
0
U
m
E
W
M
O
U
3
F-O
W
H
>-LL
O W
U=LL
LUHo_
F-E\
U)
WO
Z
F
x
Nm
E
Od
�Nd
QJJ
CD
8" ASPHALT
PA
31/20/11
0.7
1.3 7" BASE COURSE
1
SS
12"
9
118.5
PA
LEAN CLAY WITH SAND
CL
2
ST
12"
20.2
117
2540
Brown, moist, very soft to medium
3
SS
12"
1
119.5
5
PA
8.0
CL
4
ISSI
12"
6
17.9
SANDY LEAN CLAY
PA
Brown, moist to wet, medium
10
t
5
SS
12"
7
119.0
15.0
15
BOTTOM OF BORING
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS
Empire Laboratories
BORING STARTED 10-26-93
WL
g None W.D.IT
13,51, A.B.
BORING COIMPLETED 10-26-93
Incorporated
Division of Terracon
WL
RIG CME-;;
FOREMAN TK
WZ
Checked 24 I3rs. A.B.
APPROVED NRS
lOB H 20935273
..I
RESISTANCE R-VALUE AND EXPANSION PRESSURE
OF COMPACTED SOIL
Fi'STM - D 2844
CLIENT: LESTER KAPLAN
PROJECT: STONE RIDGE SUBDIVISION 3RD FILING,
LOCATION OF SAMPLE: COMPOSITE SAMPLE BORING NO. 3 @ 0.5' = 4.0'
TEST SPECIMEN
COMPACTION PRESSURE - PSI
DENSITY - PCF
MOISTURE -
EXPANSION PRESSURE - PSI
HORIZONTAL PRESSURE @ 160 psi
SAMPLE HEIGHT - in.
EXUDATION PRESSURE - PSI
UNCORRECTED R-VALUE
CORRECTED P.-VALUE
SAMPLE DATA
1
2
3
a
140
.104.7
108.4
116.7
21.8
18.8
15.1
0.06
0.12
0.61
151
146
130
2.48
2.50
2.50
175
259
418
3.6
5.9
13.6
3.6
5.9
13.6
R-VALUE AT 300 PSI EXUDATION PRESSURE = 7.3
100
W 60
J
S
.i
Q 40
20
0 w
10
EXUDAT I Otl PRESSURE — psi
EMPIRE LFIBO .'F1TORIE:3 INC.
SUAI ARY OF TEST RESULTS
Boring
No.
Depth
Ft.
Moisture
%
Dry
Density
(PCI)
Compressive
Strengdt
(PSI)
Swell
Pressure
(PSF)
Soluble
Sulfates
%
pli
Liquid
Limit
%
Plasticity
Index
%
Group
Index
Classification
AASIPI70
USCS
Resistivity
(01IM-CM)
Penetration
Blow/In.
1
.5-1.5
16.1
4/12
4-5
11.2
6/12
9-9.9
1.3
50/11
14-15
16.5
41/12
Comp.
Samp.
.5-4.0
30.2
12.6
8.5
A-6(9); CL
2
.5-1.5
20.7
6/12
3-4
18.4
103.0
4380
4-5
20.3
2/1.2
8-9
18.0
4/12
14-15
21.2
5/12
3
.5-1.5
17.6
4/12
4-5
15.4
6/12
7-8
20.1
105.0
1 3140
8-9
21.1
6/12
14-15
16.7
4/12
Comp.
Samp.
.5-4.0
34.2
14.9
10.0
A-6(10); CL
4
.5-1.5
17.8
7/12
3-4
22.2
98.7
2210
4-5
24.9
2/12
8-9
17.0
3/12
SUMMARY OF TEST RESULTS
t.
•
•Comprcssivc
•Strcngdi
Swell
---won
Pressure
Plasticity
Index
Classification
AAS11T0
USCS
Resistivity
•
Penetration
Blow/in.
7/12
7/12
3/12
5/12
7/12
1/12
6/12
7/12
DRILLING AND EXPLORATION
DRILLING & SAMPLING SYMBOLS:
R : Ring Barrell - 2.42" I.D., 3" O.D., unless otherwise noted
SS : Split Spoon - 1%" I.D., 2" O.D., unless otherwise noted
PS : Piston Sample
ST : Thin -Walled Tube- 2" O.D.; unless otherwise noted
WS : Wash Sample
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
DC :,Dutch Cone
WB : Wash Bore
Penetration Test: 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 groundwater. In low permeability soils, the accurate determination of
groundwater 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-2487 and D-2488.
Coarse Grained Soils have more 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 PROPORTIONS OF
SAND AND GRAVEL
Descriptive Term(s)
(of Components Also
Percent of
Present in Sample)
Dry Weight
Trace
< 15
With
15 - 29
Modifier
> 30
RELATIVE PROPORTIONS OF FINES
Descriptive Term(s)
(of Components Also
Percent of
Present in Sample)
Dry Weight
Trace
< 5
With
5 - 12
Modifier
> 12
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
GRAIN SIZE TERMINOLOGY
Major Component
of Sample
Size Range
Boulders
Over 12 in. (300mm)
Cobbles
12 in, to 3 in.
(300mm to 75mm)
Gravel
3 in. to #4 sieve
(75mm to 4.75mm)
Sand
#4 to #200 sieve
(4.75mm to 0.075mm)
Silt or Clay
Passing #200 Sieve
(0.075mm)
Empire Laboratories, Inc.
A Division of The Terracon Companies, Inc.
bvjIFIED SOIL CLASSIFICATION SYSTEM
Clean Gravels Less
than 5% finest
Cu > 4 and 1 < Cc <3E
— — —
Cu < 4 and/or 1 > Cc > 3E
Gravels with Fines c
more than 12% fines
Fines classify as ML or MH
Fines classify as CL or CH
Clean Sands Less
Cu > 6 and 1 < Cc < 3E
than 5% finesE
Cu < 6 and/or 1 > Cc > 3E
Sands with Fines
Fines classify as ML or MH
more than 12% fines°
Fines Classify as CL or CH
inorganic
PI > 7 and plots on or above "A line'
PI < 4 or plots below "A" line
organic
Liquid limit - oven dried
< 0.75
Liquid limit - not dried
inorganic
PI plots on or above "A" line
PI lots below "A" line
organic
Liquid limit - oven dried
< 0.75
Liquid limit - not dried
ABased on the material passing the 3-in.
(75-mm) sieve
'if field sample contained cobbles or
•`Cu'Di61D10 Cc'
D:6 x D66
boulders, or both, add "with cobbles or
boulders, or both" to group name.
cGravels with 5 to 12% fines require dual
ref soil contains > 15% sand, add "with
symbols:
sand" to group name.
GW-GM well -graded gravel with silt
'If fines classify as CL-ML, use dual symbol
GW-GC well -graded gravel with clay
GC -GM, or SC-SM.
GP -GM poorly graded gravel with silt
"If fines are organic, add "with organic fines"
GP -GC poorly graded gravel with clay
to group name.
"Sands with 5 to 12% fines require dual
'If soil contains > 15% gravel, add "with
symbols:
gravel" to group name.
SW-SM well -graded sand with silt
'If Anerberg limits plot in shaded area, soil is
SW -SC well -graded sand with clay
a CL-ML, silty clay.
SP-SM poorly graded sand with silt
SP-SC poorly graded sand with clay
60
Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests"
Coarse -Grained
Soils more than
50% retained on
No. 200 sieve
Fine -Grained Soils
50% or more
passes the
No. 200 sieve
Gravels more than
50% of coarse
fraction retained on
No. 4 sieve
Sands 50% or more
of coarse fraction
passes No. 4 sieve
Silts and Clays
Liquid limit less
than 50
Silts and Clays
Liquid limit 50
or more
Soil Classification
Group pGroup Name
E
GW Well -graded graveP
GP
Poorly graded grave
GM
Silty gravel,G,H
GC
Clayey gravelr•C•"
SW
Well -graded sand'
SP
Poorly graded sand
SM
Silty sand°•"I°'"
SC
Clayey sand"
CL
Lean clav"-L"
OL
Organic silt"'-0
CH Fat clay L""' MH Elastic SiltLL
OH
Highly organic soils Primarily organic matter, dark In color, and organic odor PT Peat
`If soil contains 15 to 290/6 plus No. 200, add
.with sand" or "with gravel", whichever is
predominant.
`if soil contains > 30% plus No. 200
predominantly sand, add "sandy" to group
name.
MY soil contains > 30% plus No. 200,
predominantly gravel, add "gravelly" to group
name.
"Pl > 4 and plots on or above "A" line.
°PI < 4 or plots below "A" line.
'PI plots on or above "A" line.
°PI plots below "A" line.
s IItRLM.O
hr Ncs 0,e6en el Me-pmined mil.
i
and !nerolned Iroeilen or eoene-
'
6raned eew
t\ ,
\�
�'
McNmnq 0.]] ILL to 2C)
p
r
Ew.l� d V
venlcd a LL - 16 le R " 7.
Ncn R " 0.6 ILL
i •
O�
G\.
i
MH OR
OH
i
d ktalt+sc
-
ML oR OL
i
0
0 +6 +6 20 00
b 00 60 70 W W +00 lee
LIQUID LIMIT (LL)
Empire Laboratories, Inc.
A Division of The Terracon Companies, Inc.
Mr. Lester Kaplan
ELI Project No. 20935273
We have appreciated 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 do
not hesitate to contact us.
Sincerely, fF' °; ,'.r = ,` :•.
EMPIRE LABORATORIES, INC.
A Division of The Terracon Companies, Inc. (; Ai3
Nei . Sherrod
Senior Engineering Geologist -�
Reviewed by: -•
a'
Chester C. Smith, P.E. - `
Division Manager
NRS/CCS/cic .3',�``'
Copies to: Addressee (2)
RBD, Inc. - Mr. Stan Meyers (1)
LABORATORY TESTS
SIGNIFICANCE AND PURPOSE
TEST
SIGNIFICANCE I
PURPOSE
California
Used to evaluate the potential strength of subgrade soil, subbase,
Pavement
Bearing
and base course material, including recycled materials for use in
Thickness
Ratio
road and airfield pavements.
Design
Consolidation
Used to develop an estimate of both the rate and amount of both
Foundation
differential and total settlement of a structure.
Design
Used to determine the consolidated drained shear strength of soil
Bearing Capacity,
Direct
or rock.
Foundation Design &
Shear
Slope Stability
Dry
Used to determine the in -place density of natural, inorganic, fine-
Index Property
Density
grained soils.
Soil Behavior
Expansion
Used to measure the expansive potential of fine-grained soil and to
Foundation & Slab
provide a basis for swell potential classification.
Design
Gradation
Used for the quantitative determination of the distribution of
Soil
particle sizes in soil.
Classification
Liquid &
Used as an integral part of engineering classification systems to
Soil
Plastic Limit,
characterize. the fine-grained fraction of soils, and to specify the
Classification
Plasticity Index
fine-grained fraction of construction materials.
Oxidation-
Used to determine the tendency of the soil to donate or accept
Corrosion
Reduction
electrons through a change of the oxidation state within the soil.
Potential
Potential
Used to determine the capacity of soil or rock to conduct a liquid
Groundwater
Permeability
or gas.
Flow Analysis
Used to determine the degree of acidity or alkalinity of a soil.
Corrosion
PH
Potential
Resistivity
Used to indicate the relative ability of a soil medium to carry
Corrosion
electrical currents.
Potential
Used to evaluate the potential strength of subgrade soil, subbase,
Pavement
R-Value
and base course material, including recycled materials for.use in
Thickness
road and airfield pavements.
Design
Soluble
Used to determine the quantitative amount of soluble sulfates
Corrosion
Sulphate
within a soil mass.
Potential
Used to determine the quantitative amounts of sulfides within a
Corrosion
Sulfide Content
soil mass.
Potential
To obtain the approximate compressive strength of soils that
Bearing Capacity
Unconfined
possess sufficient cohesion to permit testing in the unconfined
Analysis for
Compression
state.
Foundations
Water
Used to determine the quantitative amount of water in a soil mass.
Index Property
Content
Soil Behavior
Empire Laboratories, Inc.
A Division of The Terracon Companies, Inc.
REPORT TERMINOLOGY
(Based on ASTM D653)
Allowable Soil
The recommended maximum contact stress developed at the interface of the
Bearing Capacity
foundation element and the supporting material.
Alluvium
Soil, the constituents of which have been transported in suspension by flowing
water and subsequently deposited by sedimentation.
Aggregate Base
A layer of specified material placed on a subgrade or subbase usually beneath
Course
slabs or pavements.
Backfill
A specified material placed and compacted. in a confined area.
Bedrock
A natural aggregate of mineral grains connected by strong and permanent
cohesive forces. Usually requires drilling, wedging, blasting or other methods of
extraordinary force for excavation.
Bench
A horizontal surface in a sloped deposit.
Caisson (Drilled pier
A concrete foundation element cast in a circular excavation which may have an
or Shaft)
enlarged base. Sometimes referred to as a cast -in -place pier or drilled shaft.
Coefficient of
A constant proportionality factor relating normal stress and the corresponding
Friction
shear stress at which sliding starts between the two surfaces.
Colluvium
Soil, the constituents of which have been deposited chiefly by gravity such as
at the foot of a slope or cliff.
Compaction
The densification of a soil by means of mechanical manipulation.
Concrete Slab -on-
A concrete surface Layer cast directly upon a base, subbase or subgrade, and
Grade
typically used as a floor system.
Differential
Unequal settlement or heave between, or within foundation elements of a
Movement
structure.
Earth Pressure
The pressure or force exerted by soil on any boundary such as a foundation
wall.
ESAL
Equivalent Single Axle Load, a criteria used to convert traffic to a uniform
standard, (18,000 pound axle loads).
Engineered Fill
Specified material placed and compacted to specified density and/or moisture
conditions under observations of a representative of a geotechnical engineer.
Equivalent Fluid
A hypothetical fluid having a unit weight such that it will produce a pressure
against a lateral support presumed to be equivalent to that produced by the
actual soil. This simplified approach is valid only when deformation conditions
are such that the pressure increases linearly with depth and the wall friction is
neglected.
Existing Fill (or
Materials deposited through the action of man prior to exploration of the site.
man-made fill)
Existing Grade
The ground surface at the time of field exploration.
Empire Laboratories, Inc.
A Division of The Terracon Companies, Inc.
REPORT TERMINOLOGY
(Based on ASTM D653)
Expansive Potential The potential of a soil to expand (increase in volume) due to absorption of
moisture.
Finished Grade
The final grade created as, a part of the project.
Footing
A portion of the foundation of a structure that transmits loads directly to the
soil.
Foundation
The lower part of a structure that transmits the loads to the soil or bedrock.
Frost Depth
The depth of which the ground becomes frozen during the winter season.
Grade Beam
A foundation element or wall, typically constructed of reinforced concrete,
used to span between other foundation elements such as drilled piers.
Groundwater
Subsurface water found in the zone of saturation of soils, or within fractures
in bedrock.
Heave
Upward movement.
Lithologic
The characteristics which describe the composition and texture of soil and
rock by observation.
Native Grade
The naturally occuring ground surface.
Native Soil
Naturally occurring on -site soil, sometimes referred to as natural soil.
Optimum Moisture
The water content at which a soil can be compacted to a maximum dry unit
Content
weight by a given compactive effort.
Perched Water
Groundwater, usually of limited area maintained above a normal water
elevation by the presence of an intervening relatively impervious continuing
stratum.
Scarify
. To mechanically loosen soil or break down existing soil structure.
Settlement
Downward movement.
Skin Friction (Side
The frictional resistance developed between soil and an element of structure
Shear)
such as a drilled pier or shaft.
Soil (earth)
Sediments or other unconsolidated accumulations of solid particles produced
by the physical and chemical disintegration of rocks, and which may or may
not contain organic matter.
Strain
The change in length per unit of length in a given direction.
Stress
The force per unit area acting within a soil mass.
Strip
To remove from present location.
Subbase
A layer of specified material in a pavement system between the subgrade and
base course.
Subgrade
The soil prepared and compacted to support a structure, slab or pavement
system.
Empire Laboratories, Inc.
A Division of The Terracon Companies, Inc.
TABLE D1
RECOMMENDED PREVENTATIVE MAINTENANCE POLICY
FOR ASPHALT CONCRETE PAVEMENTS
Distress
Distress
Recommended
Distress
Distress
Recommended
Type
Severity
Maintenance
Type
Severity
Maintenance
Low
None
Low
None
Alligator
Cracking
Patching &
. Utility Cut
Patching
Medium
Full Depth
Asphalt Concrete
Patch
Medium
Full -Depth
Asphalt Concrete
Patch
High
High
Low
None
Low
Bleeding
Polished
Aggregate
No
Medium
Surface Sanding
Medium .
High
Shallow AC Patch
High
Fog Seal
Low
None
Low
Shallow AC Patch
Medium
Clean &
Seal
Medium
Full -Depth
Asphalt Concrete
Block
Cracking
Potholes
High
All Cracks
High
Patch
Bumps &
s
Sags
Low
None
Railroad
Crossing
Low
No Policy
for
This Project
Medium
Shallow AC Patch
Medium
High
Full -Depth Patch
High
Low
None
Low
None
Medium
Full -Depth
Asphalt Concrete
Medium
Shallow AC Patch
Corrugation
Rutting
High
Patch
High
Full -Depth Patch
Low
None
Low
None
Medium
Shallow AC Patch
Medium
Mill &
Shallow AC
Depression
Shoving
High
Full -Depth Patch
High
Patch
Low
None
Low
None
Medium
Seal Cracks
Medium
Shallow
Asphalt Concrete
Edge
Cracking
Slippage
Cracking
High
Full -Depth Patch
High
Patch
Low
Clean &
Low
None
Joint
Reflection
Seal
All Cracks
Swell
Medium
Medium
Shallow AC Patch
High
Shallow AC Patch
High
Full -Depth Patch
Low
None
Low
Lane/Shoulder
Drop -Off
Weathering
& Ravelling
Fog
Seal
Medium
Medium
Shoulder
ed
Mium
High
High
Low
None
Longitudinal &
Transverse
Cracking
Empire Laboratories, Inc.
Medium
Clean &
sea'
High
All Cracks
A Division of The Terracon Companies, Inc.
TABLE D2
RECt....MENDED PREVENTATIVE MAINTENANCc POLICY
FOR JOINTED CONCRETE PAVEMENTS
Distress
Distress
Recommended
Distress
Distress
Recommended
Type
Severity
Maintenance
Type
Severity
Maintenance
Low
None
No
Polished
Severity
Groove Surface
Blow-up
Medium
Full -Depth
Aggregate
Levels
or
Concrete Patch/
Overlay
High
Slab Replacement
Defined
Low
Seal Cracks
No
Comer
Break
Popouts
Severity
Levels
None
Medium
Full -Depth
High
Concrete Patch
Defined
Low
Seal Cracks
No
Underseal,
DSlab
Seven
Seal cracks/joints
Medium
Slab
Pumping
Levels
and
Replacement
Defined
Restore
Load Transfer
High
Low
None
Low
Seal Cracks
Medium
Full -Depth Patch
Medium
Full -Depth
Durability
Punchout
Cracking
Concrete
High
Slab Replacement
High
Patch
Low
None
Low
No
Faulting
Railroad
Crossing
Policy
for this
Medium
Medium
Grind
High
High
Project
Low
None
Scaling
Low
None
Medium
Reseal
Medium
Slab Replacement,
Joint
Map Cracking
Seal
Crazing
Full -depth Patch,
High
Joints
High
or Overlay
Low
Regrade and
No
Lane/Shoulder
Medium
Fill Shoulders
Shrinkage
Severity
None
Drop-off
to Match
Cracks
Levels
i
High
Lane Height
Defined
Linear Cracking
Low
Clean &
Low
None
Longitudinal,
Transverse and
Medium
Seal all Cracks
Spalling
(Comer)
Medium
Partial -Depth
High
Full -Depth Patch
High
Diagonal
Cracks
Concrete Patch
Love
None
Low
None
Large Patching
Spelling
and
Medium
Seal Cracks or
(Joint)
Medium
Partial -Depth Patch
High
High
Reconstruct Joint
Utility Cuts
Replace Patch
Low
None
Medium
Replace
Small
Patching
Patch
Empire Laboratories, Inc.
Hi h
9
A Division of The Terracon Companies, Inc.
Mr. Lester Kaplan
ELI Project No. 20935273
TABLE OF CONTENTS
Page No.
Letterof Transmittal................................................... i
INTRODUCTION.............................................:.... 1
PROPOSED CONSTRUCTION ........................................... 1
SITE EXPLORATION .................................................. 2
Field Exploration ................................................ 2
LaboratoryTesting .............................................. 2
SITE CONDITIONS ................................................... 3
SUBSURFACE CONDITIONS .................................. ........ .3
Soil Conditions ................................................. 3
Laboratory Test Results .......................................... 4
Groundwater Conditions .......................................... 4
CONCLUSIONS AND RECOMMENDATIONS ................................. 4
Pavement Design and Construction .................................. 4
Earthwork................................................... 8
General Considerations ...................................... 8
Site Clearing ............................................. 8
Excavation .............................................. 9
Pavement Subgrade Preparation ................................ 9
Fill Materials ............................................. 9
Placement and Compaction .................................. 10
Compliance............................................. 11
GENERAL COMMENTS ............................................... 11
APPENDIX A
Figure No.
SITEPLAN ......................................................... 1
Logs of Borings .......................................... Al thru A6
APPENDIX B
Laboratory Test Data:
Hveem Stabilometer Test .................................... B1
Summaryof Test Results .................................... B2
Mr. Lester Kaplan
ELI Project No. 20935273
TABLE OF CONTENTS (Cont'd)
Page No.
APPENDIX C: GENERAL NOTES
Drilling & Exploration ............................................ C1
.Unified Soil Classification ......................................... C2
Laboratory Testing,Significance and Purpose ........................... C3
Report Terminology ............................................. C4
APPENDIX D
Recommended Preventative Maintenance -Asphalt Concrete Pavements ......... D1
Recommended Preventative Maintenance -Jointed Concrete Pavements ......... D2
v
GEOTECHNICAL ENGINEERING REPORT
PROPOSED PAVEMENT
STONE RIDGE FILING THREE
FORT COLLINS, COLORADO
ELI PROJECT NO. 20935273
NOVEMBER 10, 1993
INTRODUCTION
This report contains the results of our geotechnical engineering exploration for the proposed
streets to be constructed in Stone Ridge Filing Three and the widening of Horsetooth Road
adjacent to Filing Three located in southeast Fort Collins, Colorado. The site. is located in the
South 1 /2 of Section 21, Township 7 North, Range 68 West of the 6th.Principal Meridian.
The purpose of these services is to provide information and geotechnical engineering
recommendations relative to:
Y subsurface soil conditions
• groundwater conditions
e pavement design and construction
• earthwork
The conclusions and recommendations contained in this report are based upon the results of field
and laboratory testing, engineering analyses, and experience with similar soil and structural
conditions.
PROPOSED CONSTRUCTION
The proposed construction will consist of the construction of residential streets within Stone Ridge
Filing Three and the widening and improvements to Horsetooth Road adjacent to the south edge
of the site.
Final site grading plans were not available prior to preparation of this report. Final subgrade is
anticipated at, or near existing site grade with only minor cuts and fills anticipated. Traffic data
for the proposed streets were not available at the time this report was prepared. Pavement
thicknesses have been provided for low volume traffic, local streets and cul-de-sacs.. Additional
pavement sections will be provided when traffic data becomes available.
Mr: Lester Kaplan
ELI Project No. 20935273
SITE EXPLORATION
The scope of the services performed for this project included site reconnaissance by an
engineering geologist, a subsurface exploration program, laboratory testing and engineering
analyses.
Field Exploration: A total of six test borings were drilled to depths of 15 feet at the locations
shown on the Site Plan, Figure 1. The borings were drilled in the area of proposed streets and the
widening of Horsetooth Road. All borings were advanced with a truck -mounted drilling rig,
utilizing 4-inch diameter solid stem auger.
The location of borings were positioned in the field by measurements from existing street
intersections and topographic features. The accuracy of boring locations should only be assumed
to the level implied by the methods used to determine each.
Continuous 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 pushing thin -walled Shelby tubes, or by driving split -spoon samplers. Representative
bulk samples of subsurface materials were obtained from selected borings..
Penetration resistance measurements were taken with each sampling with the split -spoon by
driving the sampler with a 140 pound hammer falling 30 inches. When properly interpreted, the
penetration resistance is a useful index to the consistency, relative density or hardness of the
materials encountered.
Groundwater conditions were evaluated in each boring at the time of site exploration, and one day
after drilling.
Laboratory Testing: All samples retrieved during the field exploration were returned to the
laboratory for evaluation by the project geotechnical engineer, and were classified in accordance
with the Unified Soil Classification system described in Appendix C. At that time, the field
descriptions were confirmed or modified as necessary, final boring logs prepared, and an applicable
laboratory testing program was formulated to determine engineering properties of the subsurface
materials. Boring Logs for the project are presented in Appendix A.
Selected soil samples were tested for the following engineering properties:
2
Mr. Lester Kaplan
ELI Project No. 20935273
• Water content • Plasticity
• Dry density • Soluble sulphate content
• Unconfined compression • R-Value
The significance and purpose of each laboratory test is described in Appendix C. Laboratory test
results are presented in Appendix B, and were used for the geotechnical engineering analyses, and
the development of foundation and earthwork recommendations. All laboratory test were
performed in general accordance with applicable ASTM, local or other accepted standards.
SITE CONDITIONS
The site is currently a vacant area located just east of the portion of Stone Ridge currently being
developed. The property is vegetated with grass and weeds, is relatively flat and has minor
drainage to the northeast. The site is surrounded by open farmland to the north, a single-family
residential development to the west, Horsetooth Road to the south and vacant land to the east.
SUBSURFACE CONDITIONS
Soil Conditions: As presented on Logs of Borings, the subsurface soils encountered at the site are
described in order of increasing depths:
• Pavement: Eight inches of asphalt underlain by seven inches of gravel base course were
encountered in Boring 6. drilled through the existing pavement of Horsetooth Road. A 6-
inch layer of gravel base course was encountered at the surface of Boring 3.
• Fill Material: A 6-inch layer of fill material was encountered below the gravel surfacing in
Boring 3. The fill consists of lean clay with sand. The lean clay is moist and moderately
plastic.
• Lean Clay With Sand: This stratum underlies the asphalt and fill and extends to depths of
3 to 8 feet below the surface. The lean clay is brown, moist, moderately plastic and
contains varying amounts of sand.
• Sandy Lean Clay: This stratum underlies the upper clay and extends to the gravel below
and/or the depths explored. The lower red sandy lean clay is moist to wet and moderately
plastic.
3
Mr. Lester Kaplan
ELI Project No. 20935273
o Poorly Graded Gravel With Sand and Clay: This stratum was encountered in Boring 1 at
a depth of 8 feet and extends beyond the depths explored. The gravel contains varying
amounts of sand and/or clay, minor amounts of gravel, cobbles ranging in size up to 4 to
6 inches, is moist to wet and dense to very dense.
Laboratory Test Results: Laboratory test results indicate that the subsoils at shallow depth are
moist, moderately expansive and exhibit low subgrade bearing characteristics.
Groundwater Conditions: Groundwater was encountered at depths of 12'/2 to 14 feet in Borings
2 through 5 at the time of field exploration. No groundwater was encountered in Borings 1 and
6 at the time of drilling. When checked 24 hours after drilling, groundwater was measured at
depths of 12 to 13YZ feet in all test borings. These observations represent only current
groundwater conditions, 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 irrigation demands on and adjacent to the site. In addition, water levels may be effected by
the subdrain construction below the sewer at the site.
Fluctuations in groundwater levels can best be determined by implementation of a groundwater
monitoring plan. Such a plan would include installation of groundwater monitoring wells, and
periodic measurement of groundwater levels over a sufficient period of time.
CONCLUSIONS AND RECOMMENDATIONS
Pavement Design and Construction: Traffic criteria for pavement thickness designs for light
traffic, residential streets and cul-de-sacs include Equivalent Single Axle Loads of 36,500. At the
time of the site exploration, traffic data was not available forthe proposed streets within the
subdivision. When traffic data becomes available, additional pavement sections will be provided
in an addendum to this report.
Design of pavements for the project have been based on the procedures outlined in the 1986
Guideline for Design of Pavement Structures by the American Association of State Highway and
Transportation Officials (AASHTO).
Based upon AASHTO criteria, Colorado is located within Climatic Region VI of the United States.
This region is characterized as being dry, with hard ground freeze and spring thaw. The spring
thaw condition typically results in saturated or near -saturated subgrade soil moisture conditions.
The AASHTO criteria suggests that these moisture conditions are prevalent for approximately
12.5% of the annual moisture variation cycle.
n