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GEOTECHNICAL ENGINEERING REPORT
58.6 ROAD (KIMBALL CREEK)
58.9 ROAD TO 58.7 ROAD MESA COUNTY, COLORADO
February 9, 2018
Prepared By:
Prepared For:
Mr. Eric Krch, P.E. SGM, Inc. 744 Horizon Court, Suite 250 Grand Junction, CO 81506
Project No. 17-079G-G1
58.6 Road (Kimball Creek) Project No. 17-079G-G1 Mesa County, Colorado
i
TABLE OF CONTENTS
1.0 PROJECT INFORMATION .................................................................................. 1
1.1 Purpose and Scope .................................................................................. 1 1.2 Site Conditions ......................................................................................... 1 1.3 Proposed Construction ............................................................................. 1
2.0 SITE INVESTIGATION ........................................................................................ 2
2.1 Subsurface Investigation .......................................................................... 2 2.2 Subsurface Conditions ............................................................................. 2 2.2.1 Groundwater ........................................................................................ 3
3.0 SITE GRADING ................................................................................................... 3
4.0 RETAINING WALL RECOMMENDATIONS ......................................................... 4
4.1 Lateral Earth Pressures ............................................................................ 5 5.0 CONCRETE ........................................................................................................ 6
6.0 PAVEMENT RECOMMENDATIONS ................................................................... 6
6.1 Subgrade Strength Evaluation .................................................................. 6 6.2 Hot Mix Asphalt Pavement Design ........................................................... 7 6.2.1 Hot Mix Asphalt Type ........................................................................... 8
6.3 Pavement Subgrade Preparation ............................................................. 8 6.4 Drainage Considerations .......................................................................... 9
7.0 LIMITATIONS ...................................................................................................... 9
LIST OF FIGURES
Figure 1 – Approximate Test Hole Locations
LIST OF APPENDICES
Appendix A – Logs of Exploratory Borings
Appendix B – Laboratory Test Results
Appendix C – Pavement Calculations
58.6 Road (Kimball Creek) Project No. 17-079G-G1 Mesa County, Colorado
1
1.0 PROJECT INFORMATION 1.1 Purpose and Scope
This report presents the results of our geotechnical investigation and pavement design for the
58.6 Road (Kimball Creek Road) improvements from 58.9 Road (Buzzard Creek Road) to 58.7
Road in Mesa County, Colorado. The project includes improvements and realignment of this
portion of 58.6 Road, also known as Kimball Creek Road. The purpose of this study was to
evaluate the geotechnical characteristics of the on-site soils and provide retaining wall
recommendations and pavement designs for the proposed roadway.
The site investigation consisted of geologic reconnaissance and exploratory test hole drilling to
investigate subsurface conditions. Test hole drilling was observed by a representative of RJ
Engineering. Samples obtained during the field exploration were examined by the project
personnel and representative samples were subjected to laboratory testing to determine the
engineering characteristics of materials encountered. This report summarizes our field
investigation, the results of our analyses, and our conclusions and recommendations based on
the proposed construction, site reconnaissance, subsurface investigation, and results of the
laboratory testing.
1.2 Site Conditions The project area is located on Kimball Creek Road from 58.9 Road (Buzzard Creek Road) to
58.7 Road in Mesa County, Colorado. The roadway steeply climbs upward from Buzzard Creek
Road to 58.7 Road. The total elevation change is about 120 feet. The adjacent properties
consist of gently to steeply sloping topography with localized areas of very steep cut slopes on
the uphill side and very steep fill slopes on the downhill side of the roadway. A residential drive
accesses the roadway near the top of the hill on the northern end of the site.
1.3 Proposed Construction The project consists of reconstruction of Kimball Creek Road from Buzzard Creek Road to 58.7
Road. Plans were not available at the time of this report. We anticipate cut walls will be
planned on the uphill side of the roadway to accommodate drainage and widening of the
roadway. In addition, fill walls or reinforced slopes may be planned on the downhill side of the
58.6 Road (Kimball Creek) Project No. 17-079G-G1 Mesa County, Colorado
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road. Cut walls will likely be a soil nail system, and fills walls will be gravity, MSE or
conventional cast-in-place. We anticipate maximum wall heights of 10 to 15 feet.
2.0 SITE INVESTIGATION 2.1 Subsurface Investigation
Five test holes were drilled on January 9, 2018. The approximate locations of the test holes are
presented on Figure 1. All test holes were drilled within the existing roadway. All test holes
were advanced with a CME 55 rubber track rig using 4-inch continuous flight auger to pre-
determined depths where a modified California or standard split-spoon sampler was used to
record blow counts and obtain samples. Bulk samples were also obtained at depths indicated
on the test hole logs presented in Appendix A.
To perform the modified California penetration resistance tests, a 2.0-inch inside diameter
sampler was seated at the bottom of the test hole, then driven up to 12 inches with blows of a
standard hammer weighing 140 pounds and falling 30 inches utilizing an “auto” hammer (ASTM
D1586). The number of blows (Blow Count) required to drive the sampler 12 inches or a
fraction thereof, constitutes the N-value. The N-value, when properly evaluated, is an index of
the consistency or relative density of the material tested. Split spoon samples are obtained in
the same manner, but with a 1.5-inch inside diameter sampler. Test hole logs and legend are
presented in Appendix A.
2.2 Subsurface Conditions Subsurface conditions generally consisted of asphalt underlain by varying amounts of fill or
sand with gravel, cobbles and boulders. Asphalt and base coarse was encountered at select
test hole locations. Table 1 below summarizes asphalt and base course thicknesses
encountered. Fill consisting of clay with sand and gravel underlain by a natural clay was
encountered in test hole TH-4. Sand with gravel and abundant cobbles and boulders was
encountered in the remaining test holes. Sandstone bedrock was encountered at a depth of 13
feet in test hole TH-3. The fill and natural clay was generally stiff to very stiff. The sands were
medium dense to very dense.
58.6 Road (Kimball Creek) Project No. 17-079G-G1 Mesa County, Colorado
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Table 1 – Asphalt and Base Course Thicknesses
Test Hole Asphalt Thickness (inches)
Base Course Thickness (inches)
TH-1 8 10
TH-2 5 19
TH-3 4 None detected
TH-4 5 None detected
TH-5 None None detected
Two fill and natural clay samples had 53 and 82 percent fines (material passing the No. 200
sieve). Atterberg limit testing indicated the fill sample had a liquid limit of 32 percent and
plasticity index of 17 percent. Seven sand samples had 22 to 46 percent fines and liquid limits
of 20 to 32 percent and plasticity indices of 3 to 15 percent. The existing fill sample classified as
sandy, low plasticity clay (CL), the clay sample classified as a silty, low plasticity clay (CL), and
the sands as silty to slightly clayey with gravel (SC-SM, SM and SC) according to the Unified
Soil Classification System (USCS). A combination sample of test holes TH-3 and 4 was
subjected to Hveem (R-value) testing (ASTM 2844) and resulted in an R-value of 30 at an
exudation pressure of 300 psi. Chemical testing results for water soluble sulfate content are
presented under section 5.0. Results of the laboratory testing are included in Appendix B and
are summarized in the Summary of Laboratory Test Results.
2.2.1 Groundwater
Groundwater was not encountered in any test holes during drilling. The test holes were
backfilled after drilling for public safety. Variations in groundwater conditions may occur
seasonally. Local structure could cause localized areas of perched groundwater. In addition,
the amount of spring snowmelt, duration and intensity of precipitation, and the surface and
subsurface drainage characteristics of the surrounding area could also cause areas of localized
ground water.
3.0 SITE GRADING Site grading plans were not available at the time of our investigation. We anticipate minor cuts
and fills within the roadway alignment to achieve final grades. For wall areas, we anticipate cuts
58.6 Road (Kimball Creek) Project No. 17-079G-G1 Mesa County, Colorado
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and fills of up to about 10 to 15 feet. Based on our drilling and observations, we believe that the
materials encountered can be excavated by conventional construction equipment. We
recommend cut and fill slopes be constructed no steeper than 2H:1V. However, to reduce the
potential for erosion and surface instability, fill slopes of 3H:1V should be considered. If steeper
fill slopes are necessary, reinforced soil slopes can be designed to accommodate areas where
steeper fill slopes are required.
The on-site (cut) soils can be used in site grading fills provided the material is substantially free
of organic material, debris and particles are no larger than 6 inches. Onsite soils should not be
used below pavement areas. Areas to receive fill should be stripped of vegetation, organic soils
and debris. Topsoil is not recommended for fill material. Fill should be placed in thin, loose lifts
of 8 inches thick or less. We recommend fill materials be moisture conditioned to within 2
percent of optimum moisture content and compacted to at least 95 percent of maximum
standard Proctor dry density (ASTM D 698). Placement and compaction of fill should be
observed and tested by a geotechnical engineer.
4.0 RETAINING WALL RECOMMENDATIONS We anticipate soil nail walls will be required on the downhill side at 58.9 Road intersection to
accommodate phased construction and to provide room for the intersection realignment. For
soil nail walls, design parameters are typically selected by the engineer based on anticipated
installation and equipment used for constructing the wall. We are available to discuss design
options and alternatives for soil nail systems.
Fill walls may be necessary on the downhill side of the roadway to accommodate a wider
roadway platform and reduce the height of uphill cut walls. As an alternative, reinforced soil
slopes may be used in lieu of retaining walls on the downhill side of the roadway.
Foundations should be constructed on undisturbed natural soils. Loose, disturbed soils
encountered at foundation level should be removed and the foundation should be extended to
natural soils and/or replaced with properly compacted fill. We recommend fill be placed in
accordance with the specifications presented in section 3.0. The proposed retaining wall could
58.6 Road (Kimball Creek) Project No. 17-079G-G1 Mesa County, Colorado
5
be constructed as a cast-in-place concrete, gravity or MSE wall or a soil nail wall system. The
type of wall selected would depend on space constraints, wall height and budget.
1. Footings should be placed on undisturbed natural soils. Foundations can be designed for a maximum allowable soil pressure of 2,500 psf. Based on experience, we anticipate settlement of footings designed and constructed as recommended will be about 1-inch or less.
2. Using Load Resistance Factor Design criteria (LRFD), a nominal bearing capacity can be determined for shallow spread footing foundations placed on properly placed and compacted structural fill using the following equation based on a minimum footing width of 6 feet:
qn = 6.36 + 0.32*(B-2*e) where: qn – nominal bearing capacity in ksf B – footing width in feet e – eccentricity in feet
3. A coefficient of friction of 0.30 may be used for the calculation of sliding resistance when performing an external stability check.
4. Passive pressure against the sides of the footings can be used for sliding resistance and
can be calculated using an equivalent fluid unit weight of 350 pcf if granular backfill is used.
5. The soils below foundations should be protected from freezing. We recommend the bottom of foundations be constructed at least 3.0 feet below finished grade or as required by local municipal code for cast-in-place structures. For MSE walls, we recommend a minimum embedment of 1-foot below finish grade.
6. Retaining walls acting as retaining structures should be designed to resist lateral earth pressures as discussed in section 4.1 below.
7. All foundation excavations should be observed by a representative of a geotechnical engineer prior to placement of concrete.
4.1 Lateral Earth Pressures Retaining walls should be designed to resist lateral earth pressure. Retaining walls can be
backfilled with on-site or imported granular soils. For a horizontal backslope for properly placed
and compacted fill, the unfactored earth pressure can be estimated using an equivalent fluid
pressure of 50 pcf for the active condition and 65 pcf for an at-rest condition. For wall backfill
consisting of CDOT Class 1 structure backfill, walls can be designed using an equivalent fluid
58.6 Road (Kimball Creek) Project No. 17-079G-G1 Mesa County, Colorado
6
density of 40 pcf for active or 60 pcf for at rest conditions. Site retaining walls that can be
expected to deflect to mobilize the full active earth pressure condition could be designed using
an equivalent fluid pressure for active conditions. These values assume that the backfill
materials are not saturated. Wall designs should consider the influence of surcharge loading
such as traffic, construction equipment and/or sloping backfill.
Retaining walls and structures should be constructed with a drainage system to drain away any
excess water immediately behind the wall. The drainage system may consist of free-draining
gravel, pipes, drain board and/or weep holes are commonly used for wall drainage.
5.0 CONCRETE Two subsoil samples were subjected to water-soluble sulfate testing. The samples exhibited
concentrations of 0.019 and 0.096 percent which are considered negligible/low (Class 0
exposure) degree of sulfate attack for concrete exposed to these materials. The degree of
attack is based on a range of 0.00 to less than 0.10 percent water-soluble sulfates as presented
in the American Concrete Institute Guide to Durable Concrete. Due to the negligible/low
degree, no special requirements for concrete are necessary for this site.
6.0 PAVEMENT RECOMMENDATIONS Traffic information for the design of 58.6 Road was provided by the client. Twenty-year flexible
pavement Equivalent Single Axle Loads (ESALs) were calculated and used for thickness
designs. Table 2 presents a summary of the ESAL values used as pavement design inputs.
Traffic calculations and information used in the designs is presented in Appendix C.
Table 2 – Design Traffic Loading
Roadway Segment 20-Year Flexible ESALs
58.6 Road 220,088
6.1 Subgrade Strength Evaluation Based on the results of our field exploration and laboratory testing, the subgrade materials
below pavements as classified by the American Association of State Highway and
58.6 Road (Kimball Creek) Project No. 17-079G-G1 Mesa County, Colorado
7
Transportation Officials (AASHTO) consisted of A-2-4 to A-6(6). R-value testing was performed
and resulted in an R-value of 30 for the A-6 material. A design R-value of 30 was selected
based on our experience.
We recommend new fill material placed within the proposed roadway alignment below the
aggregate base course (ABC) meet a minimum R-value of 30. Aggregate base course (ABC)
should meet CDOT Class 6 specifications and have a minimum R-value of 78. The subbase
should meet CDOT Class 2 or 3 specifications and have a minimum R-value of 59.
6.2 Hot Mix Asphalt Pavement Design For the hot mix asphalt (HMA) pavement thickness designs, resilient modulus of 6,849 psi was
calculated from the R-value of 30 using the AASHTO Design Manual. Table 3 presents the
input design parameters used for the designs of flexible pavement sections for 58.6 Road.
Table 3– Flexible Pavement Design Parameters for 58.6 Road HMA Design Inputs
Initial Serviceability 4.2 Reliability Level, % 90
Terminal Serviceability 2.5 Subgrade Resilient Modulus, MR, psi 6,849
Design Subgrade R-value 30 HMA Str. Layer Coefficient 0.44
20 Year Design ESAL 220,088 ABC Str. Layer Coefficient 0.15
Subbase Str. Layer Coefficient 0.11
A pavement section is a layered structure designed to disperse dynamic traffic loads to the
subgrade. The performance of the pavement structure depends on the traffic loadings and
physical properties of the subgrade materials. Recommended pavement design thickness
sections are summarized below.
HMA pavement design calculations were performed using the guidelines from the AASHTO
Design Manual. Calculations for all pavement designs are presented in Appendix C. HMA
pavement thicknesses presented are rounded up to the nearest half-inch. HMA pavement
thicknesses are based on 20-Year ESAL loadings and are presented in Table 4.
58.6 Road (Kimball Creek) Project No. 17-079G-G1 Mesa County, Colorado
8
Table 4 – Recommended Pavement Sections for 58.6 Road
Roadway Pavement Type Design Life (years) Thickness (inches)
58.6 Road
HMA 20 6.5” HMA
HMA + ABC 20 5” HMA + 5” ABC
HMA + ABC + Subbase 20 5” HMA + 4” ABC + 4” Subbase
6.2.1 Hot Mix Asphalt Type
We recommend that the asphalt mix for this project meet the specifications for Grading SX (75)
in accordance with the specifications. The number of SuperPave Gyratory revolutions (Ndes)
for the asphalt mixes should be at 75 gyrations is recommended if the design ESALs are below
3 million. We recommend that unmodified performance grade asphalt binder meeting the
CDOT requirements for performance grade PG 58-28 be used in both the lower and top lifts for
58.6 Road. PG 58-28 is a 98% reliability binder for both binder rutting resistance and thermal
cracking for the Collbran area based on data from the FHWA Binder Selection Program, LTPP
Bind. The lower lift should meet the requirements for SX (75) and be placed at thicknesses of
three inches. The top 2-inch lift should conform to SX (75) with PG 58-28 binder.
Aggregates for hot plant mix bituminous pavement should be of uniform quality, composed of
clean, hard, durable particles of crushed stone, gravel, or slag. Excess of fine material should
be wasted before crushing. The specified gradations for the above mixes are published in
Tables 703-4 and 703-5 of the 2017 CDOT Standard Specifications.
6.3 Pavement Subgrade Preparation We recommend that the top 6 inches of the subgrade for the entire roadway width be scarified
and recompacted in compliance with CDOT Standard Specifications. We recommend that a
separator geotextile Class 1 conforming to the requirements listed in Section 712.08 of the 2017
CDOT Standard Specifications be placed between the subgrade and the ABC Class 6 or Class
2 in conformance with Section 420.07 where subgrade soils consist of clay. Based on our
58.6 Road (Kimball Creek) Project No. 17-079G-G1 Mesa County, Colorado
9
investigation, clay was encountered in the area of test hole TH-4. The subgrade and ABC
should be compacted in accordance with the requirements shown in Section 203.07 of the 2017
CDOT Standard Specifications.
The pavement subgrade should be proof rolled with a heavily loaded pneumatic-tire vehicle.
Areas that deform more than ½-inch under heavy wheel loads should be removed, replaced if
necessary and reworked to achieve a stable subgrade prior to paving. We recommend that
proof rolling and compaction tests be observed and documented by a representative of the
engineer.
6.4 Drainage Considerations The collection and diversion of surface drainage away from paved areas is critical to the
satisfactory performance of the pavement. Proper drainage design should include prevention of
ponding of water on or immediately adjacent to pavement areas. Concentrated runoff should be
avoided in areas susceptible to erosion. Slopes and other stripped areas should be protected
against erosion by re-vegetation or other methods.
7.0 LIMITATIONS This study was conducted in accordance with generally accepted geotechnical engineering
practices in this area for use by the client for design purposes. The conclusions and
recommendations submitted in this report are based upon the data obtained from exploratory
test holes, field reconnaissance and anticipated construction. The nature and extent of
subsurface variations across the site may not become evident until excavation is performed. If
during construction, conditions appear to be different from those described herein; this office
should be advised at once so reevaluation of the recommendations may be made. We
recommend on-site observation of excavations by a representative of the geotechnical
engineer.
The scope of services for this project did not include, specifically or by implication, any
environmental or biological (e.g., mold, fungi, and bacteria) assessment of the site or
identification or prevention of pollutants, or conditions or biological conditions. If the owner is
58.6 Road (Kimball Creek) Project No. 17-079G-G1 Mesa County, Colorado
10
concerned about the potential for such contamination, conditions or pollution, other studies
should be undertaken.
The report was prepared in substantial accordance with the generally accepted standards of
practice for geotechnical engineering as exist in the site area at the time of our investigation.
No warranties, express or implied, are intended or made.
Respectfully Submitted:
RJ Engineering & Consulting, Inc.
Richard D. Johnson, P.E. Project Manager
TH-1
TH-2
TH-3
TH-4
TH-5
TH-1
LEGEND:
Indicates approximate test hole location
1. Base drawing from Google Earth.
NOTES:
Approximate
Test Hole Locations
0 100'200'
Figure
1
SCALE: 1" = 200'
N
58.6 Road (Kimball Creek), Mesa County
PROJECT NO:PROJECT:
17-079G-G1
58.6 Road (Kimball Creek) Project No. 17-079G-G1 Mesa County, Colorado
APPENDIX A
Logs of Exploratory Borings
58.6 Road (Kimball Creek) Project No. 17-079G-G1 Mesa County, Colorado
APPENDIX B
Laboratory Test Results
Project No:
Grain Size Analysis Atterberg Limits
TH-1 0-4 Bulk 7.2 24 50 26 20 17 3 SAND, silty (SM)
TH-2 4 CA 8.4 109 31 SAND, silty (SM)
10-18 Bulk 3.9 19 59 22 SAND, silty (SM)
TH-3 0-4 Bulk 5.0 29 21 15 6 SAND, silty to clayey (SC-SM)
4 CA 11.9 112 46 0.096 SAND, silty (SC)
10-13 Bulk 5.6 21 40 39 SAND, clayey (SC)
TH-4 0-4 Bulk 11.4 53 32 15 17 FILL, clay, sandy (CL)
4 CA 18.8 96 82 0.019 CLAY, sandy (CL)
TH-5 0-4 Bulk 6.4 44 32 17 15 SAND, clayey (SC)
TH-3 & 4 0-4 Combo 6.6 16 43 41 25 14 11 30 SAND, clayey (SC)
LL (%)
58.6 Road, Mesa County
PI (%)
Description
Water Soluble Sulfate
(%)
R-value at 300
psi
RJ Engineering & Consulting, Inc.
Sample Type
Dry Density (pcf)
Gravel > #4 (%)
Moisture Content
(%)PL (%)
Sample Location
Test Hole Depth (ft)
Summary of Laboratory Test Results
Sand (%)
17-079G-G1 Project Name:
Fines < #200
(%)
CA-Indicates modified California samplerBulk-Indicates bulk sample from auger cuttings Page 1 of 1
Sample Description: Gravel (%) 24 Liquid Limit (%) 20From: Sand (%) 50 Plastic Limit (%) 17
Silt & Clay (%) 26 Plasticity Index (%) 3
Sample Description: Gravel (%) 19 Liquid Limit (%)From: Sand (%) 59 Plastic Limit (%)
Silt & Clay (%) 22 Plasticity Index (%)
17-079G-G1B-1
SAND, silty (SM)TH-1 at 0-4 feet
SAND, silty (SM)TH-2 at 10-18 feet
SIEVE ANALYSIS Project No.:Figure No.:
0
10
20
30
40
50
60
70
80
90
100
0.010.11101001000
Perc
ent P
assi
ng
Particle Size (mm)
20040103/8" 41/2"3/4"3"12" 6" 1" 30 508 16
Sieve Analysis Hydrometer Analysis
Sieve Opening in Inches U.S. Standard Sieves Size in mm
1002"
0
10
20
30
40
50
60
70
80
90
100
0.010.11101001000
Perc
ent P
assi
ng
Particle Size (mm)
Sieve Analysis Hydrometer Analysis
Sieve Opening in Inches U.S. Standard Sieves Size in mm
20040103/8" 41/2"3/4"3"12" 6" 1" 30 508 16 1002"
Sample Description: Gravel (%) 21 Liquid Limit (%)From: Sand (%) 40 Plastic Limit (%)
Silt & Clay (%) 39 Plasticity Index (%)
Sample Description: Gravel (%) 16 Liquid Limit (%) 25From: Sand (%) 43 Plastic Limit (%) 14
Silt & Clay (%) 41 Plasticity Index (%) 11
17-079G-G1B-2
SAND, silty (SC-SM)TH-3 at 10-13 feet
SAND, clayey (SC)TH-3 & 4 at 0-4 feet
SIEVE ANALYSIS Project No.:Figure No.:
0
10
20
30
40
50
60
70
80
90
100
0.010.11101001000
Perc
ent P
assi
ng
Particle Size (mm)
20040103/8" 41/2"3/4"3"12" 6" 1" 30 508 16
Sieve Analysis Hydrometer Analysis
Sieve Opening in Inches U.S. Standard Sieves Size in mm
1002"
0
10
20
30
40
50
60
70
80
90
100
0.010.11101001000
Perc
ent P
assi
ng
Particle Size (mm)
Sieve Analysis Hydrometer Analysis
Sieve Opening in Inches U.S. Standard Sieves Size in mm
20040103/8" 41/2"3/4"3"12" 6" 1" 30 508 16 1002"
58.6 Road (Kimball Creek) Project No. 17-079G-G1 Mesa County, Colorado
APPENDIX C
Pavement Calculations
TRAFFIC LOADINGFlexible (HMA) Design58.6 Road (Kimball Creek) Project No. 17-079G
Current ADT: 161 vehicles per day Design Life = 20 yearsProjected ADT: 235 vehicles per dayAverage ADT: 198 vehicles per day Growth Rate = 1.9% per year
Projected ADT = 235 vehicles per day
Separate Equivalency EquivalentADT Factor ADT
Combination Trucks: 22% 44 1.087 47Single Unit Trucks: 5% 10 0.249 2Cars & Light Trucks: 73% 145 0.003 0
100% 198 50
Total ESAL: 366,814Lanes per direction: 1 lane(s)Lane Factor: 0.6
Design ESAL: 220,088
Anticipated Traffic
AASHTO PAVEMENT DESIGNFlexible (HMA) Design58.6 Road (Kimball Creek) Project No. 17-079G
R-value = 30S1 = 5.214Mr = 6,849 psiW18 = 220,088Log(W18)= 5.343Reliability = 90 %ZR = -1.282Deviation, So = 0.49po = 4.2
pt = 2.5∆psi = 1.7Log(W18)= 5.343Difference = 0.000
Design SN = 2.86
Structural Drainage Thickness Width Calculated SNLayer Material Coefficient Coefficient (inches) (feet) (inches)
HMA 0.44 1 6.5 12 2.86Totals - - 6.5 - 2.86
Structural Drainage Thickness Width Calculated SNLayer Material Coefficient Coefficient (inches) (feet) (inches)
HMA 0.44 1 5.0 12 2.20ABC 0.15 1 5.0 12 0.75
Totals - - 10.0 - 2.95
Structural Drainage Thickness Width Calculated SNLayer Material Coefficient Coefficient (inches) (feet) (inches)
HMA 0.44 1 5.0 12 2.20ABC 0.15 1 4.0 12 0.60
Subbase 0.11 1 4.0 12 0.44Totals - - 13.0 - 3.24
ABC - Aggregate Base Course consisting of CDOT Class 6 (R-value > 78)Subbase - Subbase consisting of CDOT Class 1 or 2 (R-value > 69)
Full Depth Hot Mix Asphalt (HMA)
Hot Mix Asphalt (HMA) over Aggregate Base Course (ABC)
Hot Mix Asphalt (HMA) over Aggregate Base Course (ABC) over Subbase