HomeMy WebLinkAboutProject Narrative6SGM
MEMORANDUM
TO: John Plano, arfield County Building Official
FROM: D v'd4 , P.E.
DATE: March 5, 2026
RE: Elk Mesa Grading Permit Narrative
This narrative addresses the application requirements, contains a link to the stamped
26Mb project plans, and intends to aid County review of the project. Please feel free to
call me for clarification on any aspect of this project.
Excerpts from the application are listed below with SGM response in blue.
GRADING PERMIT REQUIREMENTS PERMIT APPLICATION & SUBMITTAL
REQUIREMENTS (1 copy required):
• Complete application (a one -page form is available from the County) $400 check,
completed one -page form and a full-size stamped plan set were delivered to Brooke at
planning desk this morning (3/5/26). Per our discussion yesterday, 8'/2" x 11" items will
be provided electronically. SGM can provide any additional hard copies the County
requires.
The stamped project plans are available at the following link:
EM-Add1-02262026-Grading Permit-stamoed.pdf
• Vicinity Map indicating section, township and range of site, proposed location of
grading, and the site's relation to surrounding roads, municipal boundaries, and water
bodies. Shown on cover sheet of project plans.
• Site plan that shows the following within 100 feet of the proposed grading: Refer to the
plan set for below items.
i. Existing and proposed contours (see exemption below for pipelines)
ii. Delineation of area to be disturbed by grading activities
iii. Existing structures
iv. Existing and proposed roads and driveway
118 W. 6h St, Ste 200 Glenwood Springs, CO 81601 Phone: 970-945-1004 Fax: 970-945-5948
v. Property boundaries, rights -of -way sand easements Shown on plans. Note a new plat
will be recorded this year which will create lots as shown and vacate old easements as
appropriate.
vi. Floodplains, intermittent streams, wetlands and other bodies of water There are no
floodplains, streams or known wetlands on the property. The National Wetlands
Inventory Map does not show any wetlands on the property.
- Erosion Control Plan and Details. Plan shows the location of all erosion control
measures. Refer to sheet C30.
- MAJOR GRADING PERMIT ONLY:
i. Revegetation and Reclamation Plan. See attached requirements. Plans and spec
require topsoil stripping, stockpiling and replacement on disturbed areas. Specs reference
"Garfield County non -irrigated seed mix" but we'd like GarCO Vegetation Mgmt to
comment on what they'd like to see for this area/elevation.
ii. Financial security for site reclamation. Please allow the County to review the
reclamation cost estimate before providing security.OK. The Bid Schedule contemplates
9 acres of disturbed area requiring reclamation.
iii. For major grading permits, the plans must be prepared and stamped by a qualified
Colorado Professional engineer. Full-size delivered and link attached.
- Approved State Stormwater Permit if the area disturbed by grading is greater than one
acre. Owner is waiting for feedback from GarCO Planning re: 2/20/26 meeting topics.
We plan to pay for and obtain in advance of May 1 Construction Start Date. We kindly
request review of this grading permit with the understanding it's conditioned on obtaining
the State Permit.
- Soils Report: A soils report may not be required if the maximum depth of cut or fill
depth is less than 15 feet and native slopes are less than 25%.RJE Geotech report
attached.
- Drainage Report: will be required if the County believes that grading may change
drainage patterns with regard to adjacent properties, wetlands/water bodies or slopes
greater than 25%This project preserves existing drainage patterns. Dry detention ponds
are included to release stormwater at historic rates. This project has been carefully
designed so there is no development on slopes > 20%. Refer to the following link for s
"Slope Analysis" exhibit.
EM-Slope Analysis-3-3-26.pdf
Please contact me directly at cell (970)379-9792 or davek(a,sgm-inc.corn if there are any
questions regarding this project.
-------------------------------------------------------------DM K-------------------------------------------------------------
118 W. 61h St, Ste 200 Glenwood Springs, CO 81601 Phone: 970-945-1004 Fax: 970-945-5948
GEOTECHNICAL ENGINEERING REPORT
ELK MESA
GARFIELD COUNTY, COLORADO
June 17, 2025
Prepared By:
R�
PO Box 1080
Silt, CO 81652 (970) 230-9206
Project No. 25-021 R-01
Prepared For:
Barbara Neal
Elk Mesa Properties, LLC
500 North Michigan Ave.
Suite 1700
Chicago, IL 60611
Elk Mesa
Garfield County, Colorado
Project No. 25-021 R-01
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........................................................................................1
2.1 Subsurface Investigation..........................................................................1
2.2 Subsurface Conditions.............................................................................2
2.2.1 Groundwater........................................................................................3
3.0 SITE GRADING...................................................................................................3
4.0 PAVEMENT RECOMMENDATIONS...................................................................4
4.1 Subgrade Strength Evaluation..................................................................4
4.2 Chip Seal and Hot Mix Asphalt Pavement Design....................................4
4.2.1 Hot Mix Asphalt Type...........................................................................6
4.3 Pavement Subgrade Preparation.............................................................6
4.4 Drainage Considerations..........................................................................7
5.0 UTILITIES............................................................................................................7
6.0 LIMITATIONS......................................................................................................8
LIST OF FIGURES
Figure 1 — Approximate Site Location
Figure 2 — Approximate Test Pit Locations
LIST OF APPENDICES
Appendix A — Logs of Exploratory Borings
Appendix B — Laboratory Test Results
Appendix C — Pavement Calculations
Elk Mesa Project No. 25-021 R-01
Garfield County, Colorado
1.0 PROJECT INFORMATION
1.1 Purpose and Scope
This report presents the results of our geotechnical investigation and pavement design for Elk
Mesa in Garfield County, Colorado. The project roadway construction and utility installation for
the proposed subdivision. The purpose of this study was to evaluate the geotechnical
characteristics of the on -site soils and provide pavement designs for the roadways.
The site investigation consisted of geologic reconnaissance and exploratory test pit excavation
to investigate subsurface conditions. Test pit excavations were 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 north of the existing Elk Springs Subdivision in Garfield County,
Colorado (See Figure 1). The site consists of pastures and farmland with areas of natural
slopes. The adjacent properties consist of gently to steeply sloping topography.
1.3 Proposed Construction
The project consists of construction of roadways and installation of utilities to service 16 planned
lots. Plans indicated lots will be 35 to 55 acres each. We anticipate cuts and fills on the order
of 0 to 13 feet to achieve final grades.
2.0 SITE INVESTIGATION
2.1 Subsurface Investigation
Twenty-three (23) test pits were excavated on May 16, 2025. The approximate locations of the
test pits are presented on Figure 2. Test pit locations were staked by SGM. Test pits TP-5 and
6 were not excavated because permission to access these locations was not provided. All test
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Elk Mesa
Garfield County, Colorado
Project No. 25-021 R-01
pits were excavated with a Cat 314E rubber track excavator. Bulk samples were obtained at
depths indicated on the test pit logs presented in Appendix A.
2.2 Subsurface Conditions
Subsurface conditions generally consisted of topsoil underlain by varying amounts clay and/or
basalt rock. The excavator could not advance the pits to planned depths in TP-1, 7, 9, 12, 15,
20, 24, and 25 due to very hard basalt rock. Table 1 below presents the depth at which basalt
rock was encountered. The clays were generally medium stiff to stiff. The basalt rock was very
hard to extremely hard. NOTE: FINISHED GRADES REVISED
AFTER GEOTECH REPORT
Table 1 — Depth to Basalt Rock
Test Pit
Depth
feet
Planned Grade
Chan e feet
Refusal Depth
inches
TP-1
4
-3
Refusal at 8.5
TP-2
NE to 5
+5
TP-3
7
-5
TP-4
NE to 5
+12.5
TP-7
2
0
Refusal at 4.5
TP-8
3
-1
TP-9
1.5
0
Refusal at 3
TP-10
NE to 5
-1
TP-11
1.5
+1
TP-12
2
0
Refusal at 3
TP-13
NE to 5
0
TP-14
NE to 5
-1.5
TP-15
3
0
Refusal at 4
TP-16
NE to 5
0
TP-17
3
0
TP-18
2
0
TP-19
3
-1
TP-20
1.5
+3.5
Refusal at 3
TP-21
2
+1.5
TP-22
2.5
+1
TP-23
4
0
TP-24
1.5
+0.5
Refusal at 4.5
TP-25
2
0
Refusal at 3
NE — Not Encountered
2 ®✓
Elk Mesa Project No. 25-021 R-01
Garfield County, Colorado
Two topsoil samples had 16 and 47 percent fines (material passing the No. 200 sieve).
Atterberg limit testing indicated the samples had liquid limits of 39 to 43 percent and plasticity
indices of 20 to 26 percent. Eighteen clay samples had 54 to 92 percent fines and liquid limits
of 31 to 60 and plasticity indices of 13 to 30. Eleven basalt rock samples had 11 to 60 percent
fines. The topsoil samples classified as clayey sand (SC), and the clay samples classified as
silty, low plasticity clay (CL) according to the Unified Soil Classification System (USCS).
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 pits during excavation. The test pits were
backfilled immediately after excavation and sampling 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 groundwater.
3.0 SITE GRADING
We anticipate cuts of up to 5 feet and fills up to 13 feet within the roadway alignment to achieve
final grades. Based on our observations, we believe that the clay subsoils encountered can be
excavated by conventional construction equipment. Significant excavations into the basalt rock
will likely require heavy ripping, hydraulic breakers, or possibly blasting to excavate. Table 1
presents the depths at which the basalt rock was encountered. 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:1 V 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 and under the roadway platform provided
the material is substantially free of organic material, debris and particles are no larger than 6
inches. 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
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Elk Mesa
Garfield County, Colorado
Project No. 25-021 R-01
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 PAVEMENT RECOMMENDATIONS
Traffic information for the design of the roadways was estimated based on the proposed 16 lots.
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 Loadin
Roadway Segment
20-Year Flexible
ESALs
Internal Drives
6,300
4.1 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
Transportation Officials (AASHTO) consisted of A-6(4) to A-7-6(27). Based on our experience
and published literature, a design R-value of 10 was selected.
We recommend new fill material placed within the proposed roadway alignment below the
aggregate base course (ABC) meets a minimum R-value of 20. Fill should be placed in
accordance with Section 3.0 above. 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 69.
4.2 Chip Seal and Hot Mix Asphalt Pavement Design
For the chip seal (CS) and hot mix asphalt (HMA) pavement thickness designs, resilient
modulus of 3,562 psi was calculated from the R-value of 10 using the AASHTO Design Manual.
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Elk Mesa
Garfield County, Colorado
Project No. 25-021 R-01
Table 3 presents the input design parameters used for the designs of flexible pavement
sections.
Table 3— Flexible Pavement Desiqn Parameters
HMA Design Inputs
Initial Serviceability
4.2
Reliability Level, %
90
Terminal Serviceability
2.5
Subgrade Resilient Modulus, MR, psi
3,803
Design Subgrade R-value
12
HMA Str. Layer Coefficient
0.44
20 Year Design ESAL
99,094
j ABC Str. Layer Coefficient
0.15
Chip Seal Str. Layer Coefficient
0.22
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. CS and HMA
pavement thicknesses are based on 20-Year ESAL loadings and are presented in Table 4. A
geogrid alternative is presented. The geogrid should consist of a biaxial grid with material
separator such as a Tensar InterAx NX750. If a biaxial grid without separator is selected, the
grid should be installed in the center of the aggregate base course and a separate layer of
separator fabric be installed at the base of the aggregate base course.
Table 4 — Recommended Pavement Sections
Roadway
Pavement Type
Design Life
(years)
Thickness (inches)
CS + ABC
20
1 " CS + 11 " ABC
Internal
CS + ABC + Geogrid
20
1" CS + 6" ABC + Geogrid
Drives
CS + ABC + Subbase
20
1" CS + 6" ABC + 7" Subbase
HMA
20
4.5" HMA
5
Elk Mesa Project No. 25-021 R-01
Garfield County, Colorado
4.2.1 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.
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 two to 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.
4.3 Pavement Subgrade Preparation
We recommend that the top 12 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 for the entire project. 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 %-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 0
Elk Mesa
Garfield County, Colorado
Project No. 25-021 R-01
4.4 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.
5.0 UTILITIES
Utilities such as electrical, communication and water are planned. Typically, electrical and
communication lines are installed relatively shallow. However, we anticipate water lines to be
installed at a depth of 7 feet. Extremely hard basalt rock will likely be encountered and will
require heavy ripping, hydraulic breakers or possibly blasting. Table 5 shows the anticipated
areas where basalt rock will likely be encountered during water line installation based on the
preliminary design. Backfill above and below utilities should be placed in accordance with
Section 4.0 above. The type of backfill should conform to manufacturer's recommendations.
7 0
Elk Mesa
Garfield County, Colorado
Project No. 25-021 R-01
NOTE: FINISHED GRADES REVISED
AFTER GEOTECH REPORT
Table 5 — Basalt Rock Depth within Water Line Trenches
Test Pit
Depth
feet
Planned Grade
Change feet
Encounter
Basalt Rock?
TP-1
4
-3
Yes
TP-2
NE to 5
+5
No
TP-3
7
-5
Yes
TP-4
NE to 5
+12.5
No
TP-7
2
0
Yes
TP-8
3
-1
Yes
TP-9
1.5
0
Yes
TP-10
NE to 5
-1
Yes
TP-11
1.5
+1
Yes
TP-12
2
0
Yes
TP-13
NE to 5
0
No
TP-14
NE to 5
-1.5
Yes
TP-15
3
0
Yes
TP-16
NE to 5
0
Yes
TP-17
3
0
Yes
TP-18
2
0
Yes
TP-19
3
-1
Yes
TP-20
1.5
+3.5
Yes
TP-21
2
+1.5
Yes
TP-22
2.5
+1
Yes
TP-23
4
0
Yes
TP-24
1.5
+0.5
Yes
TP-25
2
0
Yes
NE — Not Encountered
Note: Values based on preliminary design.
6.0 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 pits, 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
8 0
Elk Mesa
Garfield County, Colorado
Project No. 25-021 R-01
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
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.
Principal
a.
.... Earth
25A21 R-01 EIk IJaae. G.A.W CwKy. CO
NOT TO SCALE Approximate 17d
NOTE: Base plan by Google Earth. Site Location
NOTE: FINISHED GRADES REVISED
AFTER GEOTECH REPORT
NOTE: Base plan by SGM dated 01.16.2025
LEGEND
TP-8 Indicales approximate test We location
TP-6 Indicates test pill TPs &W TP-6 could not be excavated because
pennlssian could not be *toned for access.
Elk Mesa, Garfield County, CO
a Approximate (Figure
SCALE: 1": Test Pit Locations 2
Elk Mesa
Garfield County, Colorado
Project No. 25-021 R-01
APPENDIX A
Logs of Exploratory Borings
0
Sample Types
® Bulk sample obtained from excavation at depths indicated.
Other Symbols
It Indicates excavation could not be advanced due to extremely hard subsoils.
Soil Lithology
0 TOPSOIL
ECLAY, silty to sandy, gravelly with cobbles and boulders, medium stiff to stiff, slightly moist, brown, dark brown, tan (CL)
BASALT ROCK with varying amounts of silt, clay and sand infill, gravelly, slightly moist, very to extremely hard, gray, dark gray with tan infill
(GM, ML, SM, SC)
NOTES:
1. Test pits were excavated on May 16, 2025 using a Cat 314E track mounted excavator
2. Groundwater was not encountered during excavations.
3. Test pits descriptions are subject to explanations contained in this report.
LEGEND FOR EXPLORATORY TEST PITS
Project: Project No.:
Elk Mesa, Garfield County, CO 25-021 R-01
Figure A-1
TP-1 TP-2
Final Grade Final Grade
-3 ft. +5 ft.
0
5 +
m
+
a�
+
L
O.
tv
10
15
TP-3 TP-4 TP-5
Final Grade Final Grade Not Excavated
-5 ft. +12.5 ft. (Permission to
.access not
granted)
NOTE: FINISHED GRADES REVISED
AFTER GEOTECH REPORT
TP-6 TP-7 TP-8 TP-9 TP-10
Not Excavated Final Grade Final Grade Final Grade Final Grade
(Permission to 0 ft. -1 ft. 0 ft. -1 ft.
0 access not
granted)
+ +
5 +
a�
a�
L
a
a�
10
15
LOGS OF EXPLORATORY BORINGS
- Project:
Elk Mesa, Garfield County, CO
0
15
111
15
eCt No.:
25-021R-01
Figure A-2
IJ
5
10
15
0
5
10
15
TP-11 TP-12
Final Grade Final Grade
+1 ft. 0 ft.
+
+
TP-13 TP-14
Final Grade Final Grade
0 ft. -1.5 ft.
NOTE: FINISHED GRADES REVISED
AFTER GEOTECH REPORT
TP-15 TP-16 TP-17
Final Grade Final Grade Final Grade
0 ft. 0 ft. 0 ft.
+
TP-18
Final Grade
0 ft.
LOGS OF EXPLORATORY BORINGS
Elk Mesa, Garfield County, CO
n
15
A
15
25-021 R-01
Figure A-3
TP-19 TP-20 TP-21 TP-22
Final Grade Final Grade Final Grade Final Grade
-1 ft. +3.5 ft. +1.5 ft. +1 ft.
0 0
+
5 5
L L
O d
tU N
� 0
10 10
15 L 115
NOTE: FINISHED GRADES REVISED
AFTER GEOTECH REPORT
TP-23 TP-24 TP-25
Final Grade Final Grade Final Grade
0 ft. +0.5 ft. 0 ft.
0 0
+
+
5 5
a� a)
L L
0-
a)
10 10
15 15
LOGS OF EXPLORATORY BORINGS
Project: Project No
Elk Mesa, Garfield County, CO 25-021R-01
Figure A-4
Elk Mesa
Garfield County, Colorado
Project No. 25-021 R-01
APPENDIX B
Laboratory Test Results
0
RJ Engineering & Consulting, Inc.
Summary of Laboratory Test Results
Project No: 25-021R-01 Project Name: Elk Mesa, Garfield County, CO
Sample Location
Moisture
Content
(%)
Dry
Density
(pcf)
Grain Size Analysis
Atterberg Limits
Water
Soluble
Sulfate
AASHTO
Description
Test Pit
Depth (ft}
Sample
Type
Gravel
a�
Sand
°
Fines
< #200
LL
°
PL
°
PI
°
TP-1
3-4
BULK
16.6
84
38
17
21
A-6 (17)
CLAY, sandy (CL)
5-6
BULK
20.3
7
33
60
A-4
BASALT ROCK, silt, sandy (ML)
TP-2
2-4
BULK
10.6
87
37
17
20
A-6 (17)
CLAY, sandy (CL)
TP-3
5-7
BULK
133
90
38
15
23
A-6 (20)
CLAY, sandy (CL)
TP-4
2-3
BULK
186
76
35
16
19
A-6 (13)
CLAY, sandy (CL)
TP-7
1-2
BULK
12.6
86
38
17
21
A-6 (18)
CLAY, sandy (CL)
2-4
BULK
121
18
41
41
A-4
BASALT ROCK, sand, silty (SM)
TP-8
1.5-2.5
BULK
11.4
81
37
16
21
A-6 (16)
CLAY, sandy (CL)
TP-9
0.5-1.5
BULK
11.0
81
38
16
22
0.000
A-6 (17)
CLAY, sandy (CL)
2-3
BULK
17
42
37
21
NL
NP
NP
A-1-b (0)
BASALT ROCK, gravel, silty (GM)
TP-10
2-4
BULK
16.6
91
39
16
23
A-6 (21)
CLAY, sandy (CL)
TP-11
3-4
BULK
19.2
18
28
54
A-4
BASALT ROCK, silt, sandy (ML)
TP-12
1-2
BULK
14.7
54
33
20
13
A-6 (4)
CLAY, sandy (CL)
2-3
BULK
24.8
44
28
28
NIL
NP
NP
A-2-4 (0)
BASALT ROCK, gravel, silty (GM)
TP-13
3-5
BULK
10
92
32
17
1 15
A-6 (13)
CLAY, sandy (CL)
TP-14
3-5
BULK
10.6
87
43
16
27
A-7-6 (23)
CLAY, sandy (CL)
TP-15
2-3
BULK
15.3
91
46
17
29
A-7-6 (27)
CLAY, sandy (CL)
3-4
BULK
10.6
10
17
73
0.000
A-4
BASALT ROCK, silt, sandy (ML)
TP-16
3-5
BULK
12.9
88
37
17
20
A-6 (17)
CLAY, sandy (CL)
TP-17
2-3 1
BULK 1
131
75
44
19
25
A-7-6 (18)
CLAY, sandy (CL)
CA -Indicates modified California sampler
SS -Indicates standard split spoon sampler
Bulk -Indicates bulk sample from auger cuttings or ground surface
NL-Indicates non -liquid
NP-Indicates non -plastic
Page 1 of 2
Project No: 25-021 R-01
RJ Engineering $ Consulting, Inc.
Summary of Laboratory Test Results
Project Name: Elk Mesa, Garfield County, CO
Sample Location
Moisture
Content
Dry
D(pcf)
Grain Size Analysis
Attert.)era_ Limits
Water
Soluble
Sulfate
AASHTO
Description
Test Pit
Depth (ft)
Sample
Gravel
o�
Sand
Fines
1#200
oL
PL
%
TP-18
3-5
BULK
16.3
32
39
29
0.060
A-2-4
BASALT ROCK, sand, silty (SM)
TP-19
2-3
BULK
11.7
0
40
60
41
19
22
A-7-6 (10)
CLAY, sandy (CL)
TP-20
2-3
BULK
19.1
22
48
30
45
26
19
A-2-7 (0)
BASALT ROCK, sand, clayey (SC)
TP-21
0-2
BULK
15.2
16
39
19
20
A-2-6 (0)
TOPSOIL, SAND, clayey (SC)
4-5
BULK
12.7
27
40
33
A-2-4
BASALT ROCK, sand, silty (SM)
TP-22
1-2
BULK
13.5
66
45
15
30
A-7-6 (17)
CLAY, sandy (CL)
TP-23
2-4
BULK
12.9
74
45
19
26
A-7-6 (18)
CLAY, sandy (CL)
TP-24
0-1.5
BULK
13.9
47
43
17
26
A-7-6 (8)
TOPSOIL, SAND, clayey (SC)
1.5-2 5
BULK
19.3
45
29
26
60
38
22
A-2-7 (0)
BASALT ROCK, gravel, silty (GM)
TP-25
1-2
BULK
11.5
88
31
17
14
A-6 (11)
CLAY, sandy (CL)
2-3
BULK
18.1
63
26
11
0.000
A-1-a
BASALT ROCK, gravel, silty (GM)
*Laboratory testin b others
CA -Indicates modi�iedyCalifornia sampler
SS -Indicates standard split spoon sampler
Bulk -Indicates bulk sample from auger cuttings or ground surface
NIL -Indicates non -liquid
NP-Indicates non -plastic
Page 2 of 2
G'J�
d Coasullmg,
Engineering
d Consulting, Inc.,
Engineering
& Constilling, live,
Engineering
8 Consulting. Inc.
Engineering
�8 Consak1nu. Inc.
Engineering
& Comilling. lnc.A
Elk Mesa
Garfield County, Colorado
Project No. 25-021 R-01
APPENDIX C
Pavement Calculations
0
TRAFFIC LOADING using Volume
Flexible (HMA and Chip Seal) Design
Elk Mesa
Current ADT:
55 vehicles per day
Projected ADT:
55 vehicles per day
Average ADT:
55 vehicles per day
Project No. 25-021 R-01
Design Life = 20 years
Separate
Equivalency
Equivalent
Anticipated Traffic
ADT
Factor
ADT
Combination Trucks: 1.0%
1
1.087
0.6
Single Unit Trucks: 5.0%
3
0.249
0.7
Cars & Light Trucks: 94%
52
0.003
0.2
100% 55 1.4
Total ESAL: 10,495
Lanes per direction: 1 lane(s)
Lane Factor: 0.6
Design ESAL: 1 6,297
AASHTO PAVEMENT DESIGN using Volume
Flexible (HMA and Chip Seal) Design
Elk Mesa Project No. 25-021 R-01
R-value =
10
S1 =
3.443
Mr =
3,562 psi
W18 -
6,297
Log(W 18)=
3.799
Reliability =
80 %
ZR =
-0.841
Deviation, So =
0.49'
po =
4.2
pt =
2.5
Opsi =
1.7
Log(W18)=
3.799
Difference =
0.000
Design SN = 1 1.87
Full
Depth Hot Mix Asphalt (HMA)
Layer Material
Structural
Coefficient
Drainage
Coefficient
Thickness
inches
Width
feet
Calculated SN
inches
HMA
0.44
1
4.5
12
1.98
Totals
-
-
4.5
-
1.98
Chip Seal over Aggregate Base Course (ABC)
Layer Material
Structural
Coefficient
Drainage
I Coefficient
Thickness
inches
I Width
feet
Calculated SN
inches
Chip Seal
0.22
1
1.0
12
0.22
ABC
0.15
1
11.0
12
1.65
Totals
-
-
12.0
-
1.87
Chip Seal over Aggregate Base Course (ABC) over Subbase
Layer Material
Structural
Coefficient
Drainage
Coefficient
Thickness
inches
Width
(feet)
I Calculated SN
(inches)
Chip Seal
0.22
1
1.0
12
0.22
ABC
0.15
1
6.0
12
0.90
Subbase
0.11
1
7.0
12
0.77
Totals
-
-
14.0
-
1.89
AbL, - Aggregate base t;ourse consisting of c;uu I Gass 6 (K-value > 18)
Subbase - Subbase consisting of CDOT Class 1 or 2 (R-value > 69)