6546-A RPT OCHOCO RANGER STATION ROAD OVERLAY PAVEMENT EVALUATION Report.pdf

Pavement Evaluation

OR CROOK 123(1)

Ochoco Ranger Station Road Overlay Crook County, Oregon

December 14, 2021

(ISSUED: 02/28/2022)

Prepared for

David Evans and Associates, Inc.

2100 SW River Parkway

Portland, OR 97201

Prepared by

9750 SW Nimbus Avenue Beaverton, OR 97008-7172

(503) 641-3478 | www.gri.com

GRI 6546-A – Ochoco Ranger Station Road Overlay Report December 14, 2021 (Issued: 02/28/2022)

TABLE OF CONTENTS

1 INTRODUCTION

2 PROJECT DESCRIPTION

3 PAVEMENT DESIGN APPROACH

4 FIELD INVESTIGATIONS AND LABORATORY TESTING

4.1 Site Conditions

4.2 Subsurface Explorations

4.3 Dynamic Cone Penetration (DCP) Testing

4.4 GPR Data Collection

4.5 Laboratory Testing

5 PAVEMENT DESIGN ANALYSIS

5.1 Design Subgrade Resilient Modulus

5.2 Traffic-Loading Analysis

5.3 Flexible Pavement Rehabilitation Analysis

5.4 Flexible Pavement Full Depth Repair Analysis

6 PAVEMENT DESIGN RECOMMENDATIONS

6.1 Rehabilitation

6.2 Full-Depth Repair with Reconstruction

7 RECOMMENDATIONS FOR MATERIALS AND CONSTRUCTION

7.1 Standard Specifications

7.2 Construction Considerations

8 DESIGN REVIEW AND CONSTRUCTION SERVICES

9 LIMITATIONS

10 REFERENCES

TABLES

Table 4-1: Boring Summary Table Table 5-1: 2018 FLAP Application Traffic Information Table 7-1: Recommended Material Specifications

FIGURE

Figure 1: Site Plan

APPENDICES

Appendix A: Field Investigation and Laboratory Testing Appendix B: Ground-Penetrating Radar Appendix C: Pavement Design Calculations

GRI 6546-A – Ochoco Ranger Station Road Overlay Report Page 1

1 INTRODUCTION

As subconsultant to David Evans and Associates, Inc. (DEA), GRI completed a pavement evaluation for OR CROOK 123 (1), Ochoco Ranger Station Road in Crook County near Prineville, Oregon. This evaluation project is part of a 2018 Federal Lands Access Program (FLAP) application submitted by Crook County (County). This work follows up on the September 2020 report prepared by DEA titled, “Ochoco Ranger Station Road Overlay Final Scoping Design Report.”

2 PROJECT DESCRIPTION

The Ochoco Ranger Station Road is located approximately 15 miles southeast of Prineville, in Crook County, Oregon, and the project limits are from US Highway 26 (US 26) to approximately Coyle Creek Road. Ochoco Ranger Station Road is an 8.12-mile-long, asphalt concrete (AC)-surfaced, two-lane, two-way, major collector. Ochoco Ranger Station Road is a popular access point for outdoor recreation in the Ochoco National Forest, Walton Lake, and Big Summit Prairie areas. The road also provides access for timber-harvesting logging trucks.

We understand the County would like to place an AC overlay to preserve the current pavement condition and extend the life of the road. Other project components, to be completed by DEA, include safety improvements such as adding shoulder rock, striping, and upgrading guardrails.

3 PAVEMENT DESIGN APPROACH

GRI accomplished the pavement design analysis in general accordance with the guidelines given in the 1993 American Association of State Highway and Transportation Officials (AASHTO) Guide for Design of Pavement Structures (AASHTO Guide), the Oregon Department of Transportation (ODOT) Pavement Design Guide (ODOT Guide), and the Federal Highway administration (FHWA) Project Development Design Manual. Details of our field explorations and laboratory testing program are provided in Appendix A.

Discussion of our GPR testing and analysis is provided in Appendix B. A summary of our traffic-loading analysis and pavement-design analysis are provided in Appendix C.

4 FIELD INVESTIGATIONS AND LABORATORY TESTING

4.1 Site Conditions

The roadway is located in a shallow valley and generally follows Ochoco Creek. There is an elevation gain of approximately 600 feet from US 26 to the east end of the project. To assist us in characterizing the subgrade conditions at the site, we reviewed the U.S.

Department of Agriculture (USDA) Web Soil Survey Map (Version 17, June 11, 2020) to compare the near-surface soils shown on the USDA map with our field reconnaissance observations. The roadway alignment comprises several soil series. In a typical profile, the upper subgrade of these soil series contain low-plasticity silty, clayey soils with varying

GRI 6546-A – Ochoco Ranger Station Road Overlay Report Page 2 amounts of sand. In some areas, the soils transition to gravelly and cobbly around 18 inches below the ground surface. Our site investigation discussed in this report generally agrees with the mapped USDA soil units on Ochoco Ranger Station Road.

Based on our visual observations, the roadway appears to be in good condition. We generally observed climate-related distresses such as transverse, thermal cracking, and distresses common to chip seals such as AC bleeding/flushing and raveling.

4.2 Subsurface Explorations

4.2.1 General

The subsurface materials and conditions at the site were investigated on October 19, 2021, with nine borings designated B-1 through B-9, to a depth of about 5 feet below ground surface (BGS).

4.2.2 Pavement

In our explorations, we observed AC thickness ranging from about 6½ to 8¾ inches. The AC was underlain by an oil mat ranging in thickness from about 1 inch to 2½ inches.

Exploration B-6 was the only location we did not encounter an oil mat below the AC. The relative condition of the recovered AC pavement ranges from good to poor, with three of the cores exhibiting top-down cracking and six exhibiting delamination or stripping damage. We encountered aggregate base (AB) beneath the AC at all core locations, with thicknesses ranging from about 5 inches to about 14½ inches. The pavement-layer thicknesses are summarized in Table 4-1. A plot summarizing pavement core thicknesses and characteristics is provided on Figure 1A in Appendix A. Boring logs are presented on Figures 2A through 6A in Appendix A. Photographs of the pavement cores are provided on Figures 7A through 15A in Appendix A.

Table 4-1: BORING SUMMARY TABLE

Number

Location

Thickness, inches

Core Over Crack?

Type of Crack

Depth of Crack, inches AC

Oil Mat AB

B-1 EB OWT 8 1 12 Yes Top Down 2

B-2 WB OWT 8½ 1½ 8 Yes Top Down 2

B-3 EB OWT 7½ 1½ 11 No NA NA

B-4 WB OWT 7½ 1½ 13 No NA NA

B-5 EB OWT 8½ 2½ 9 No NA NA

GRI 6546-A – Ochoco Ranger Station Road Overlay Report Page 3

Number

Location

Thickness, inches

Core Over Crack?

Type of Crack

Depth of Crack, inches AC

Oil Mat AB

B-6 WB OWT 6½ NA 14½ No NA NA

B-7 EB OWT 8¾ 2½ 7¾ No NA NA

B-8 WB OWT 7¾ 2¼ 5 Yes Top Down 7¾

B-9 EB OWT 7 2½ 12½ No NA NA

Abbreviations: AC = Asphalt Concrete; AB = Aggregate Base; EB = Eastbound; NA = Not Applicable;

OWT = Outer Wheel Track.

4.2.3 Subgrade Soils

The subgrade soils at the core locations generally range from silty gravel to silty sand. We also encountered silt and clay in four of the nine explorations.

4.2.4 Groundwater

Groundwater was not encountered in our subsurface explorations. We anticipate the groundwater levels will fluctuate in response to seasonal variation of the nearby Ochoco Creek.

4.3 Dynamic Cone Penetration (DCP) Testing

We performed DCP testing, designated DCP-1 through DCP-9, at the core locations shown on Figure 1. We encountered refusal at exploration B-2 and B-8; therefore, we were unable to complete a DCP test at these locations. The results of the DCP tests are shown on Figures 17A through 23A and summarized in Table 2A in Appendix A.

4.4 GPR Data Collection

GRI conducted a longitudinal GPR survey along the roadway segment (i.e., parallel to the roadway centerline) for the purposes of estimating pavement surfacing depth and to identify delamination. We used our 2-gigahertz (GHz), truck-mounted antenna in each lane of travel. The length of our survey totaled approximately 85,500 linear feet. Further details of our GPR equipment and survey process are provided in Appendix B along with the results on Figures 1B through 3B.

4.5 Laboratory Testing

GRI performed laboratory testing to note the physical characteristics and modified the field classifications of the collected soil samples, where necessary. The laboratory testing program included determinations of natural moisture contents and performing Atterberg limits on subgrade soil samples.

GRI 6546-A – Ochoco Ranger Station Road Overlay Report Page 4

5 PAVEMENT DESIGN ANALYSIS

Our pavement-design analysis was conducted in order to estimate the structural requirements to meet a 20-year design period based on the existing roadway structural capacity, subgrade support conditions, and estimated traffic loading.

5.1 Design Subgrade Resilient Modulus

We used the DCP test data summarized in Appendix A to estimate the design subgrade resilient modulus value within the project limits. The DCP test results are used to estimate the California bearing ratio, which is correlated to the subgrade resilient modulus based on relationship developed by Chen, et al (1999). We estimated a design subgrade resilient modulus value of 6,100 pounds per square inch (psi) based on the 2.3-percentile value divided by 0.70. This procedure follows the statistical-reliability assumptions in the AASHTO Guide design procedure, which is based on using the average subgrade modulus as the design value provided the coefficient of variation (CoV) does not exceed 15%.

5.2 Traffic-Loading Analysis

The traffic-loading estimate for Ochoco Ranger Station Road is based on the 20-year average daily traffic (ADT) provided by the County in the 2018 FLAP application. The County provided the ADT data summarized in Table 5-1.

Table 5-1: 2018 FLAP APPLICATION TRAFFIC INFORMATION

Location 20-Year Traffic Projections

ADT 1281

Percent Trucks 3%

For our analysis, we used the critical traffic loading, which is the data listed for the north end of the project in Table 5-1. Additionally, based on a conversation with the County, we understand the typical truck traffic comprises primarily delivery or garbage trucks, occasional construction trucks, and historically trucks associated with logging operations.

In order to estimate the cumulative 18-kip Equivalent Single-Axle Load (ESAL) repetitions (traffic loading) for a 20-year design period, we used the inputs and assumptions shown in Table 1C of Appendix C. The 20-year traffic-loading estimate for Ochoco Ranger Station Road is 117,000 ESALs.

5.3 Flexible Pavement Rehabilitation Analysis

We developed rehabilitation recommendations by performing analysis in accordance with the procedures described in the 1993 AASHTO Guide using the design parameters shown in Tables 2C and 3C in Appendix C, for overlay and inlay, respectively. We took into consideration crack penetration depths and lift lines observed from the cores in selecting the milling depths evaluated for rehabilitation.

GRI 6546-A – Ochoco Ranger Station Road Overlay Report Page 5

5.4 Flexible Pavement Full Depth Repair Analysis

Using the approximated traffic-loading values and design subgrade resilient modulus value described above, we evaluated full-depth reconstruction options for localized repairs using conventional flexible pavement (i.e., AC on AB) placed over a subgrade geotextile.

We conducted the analysis in accordance with the procedures described in the 1993 AASHTO Guide using the design parameters shown in Table 4C in Appendix C.

6 PAVEMENT DESIGN RECOMMENDATIONS

Our pavement-design recommendations for the 20-year design period are given below.

6.1 Rehabilitation

Our recommendations for rehabilitation include a 2-inch overlay and a 3-inch mill and inlay. As discussed above, we observed transverse cracking, which is typically temperature related and extends the full depth of the AC surfacing. If reflective cracking is a concern, we recommend selecting rehabilitation with mill and inlay. Removing the upper portion of the AC will help to reduce the crack width, which can help to slow the progression of reflective cracking. Another alternative that may help to reduce the reflective cracking potential or slow the progression of reflective cracking is to use fibers for asphalt mixtures such as FORTA-FI®. Our recommendations for rehabilitation are as follows:

Overlay 2.0-inch-thick, ½-inch-size Dense Asphalt Concrete Pavement (ACP), Performance

Grade (PG) 64-28 (one lift) Tack Coat

Mill and Inlay 3.0-inch-thick, ½-inch-size Dense ACP, PG 64-28 (one lift) Tack Coat 3.0-inch-thick Cold Plane Pavement Removal

6.2 Full-Depth Repair with Reconstruction

During our initial field investigation, we did not identify areas with load-related fatigue cracking that would indicate the potential need for full-depth repair. We also completed visual survey using drone technology, and at the time of the survey, we did not observe areas requiring full-depth repair. Due to the time that may lapse between design and construction, for estimating purposes, we recommend assuming up to 1% of the roadway area may require full-depth repair. We recommend using the following pavement section for full-depth repair.

Full-Depth Repair with Geotextile 6.0-inch-thick, ½-inch-size Dense ACP, PG 58-28 (two equal lifts) 10.0-inch-thick, 1-inch or ¾-inch-0 Dense-Graded Aggregate Base (AB)

GRI 6546-A – Ochoco Ranger Station Road Overlay Report Page 6

Nonwoven Subgrade Geotextile Undisturbed Subgrade

7 RECOMMENDATIONS FOR MATERIALS AND CONSTRUCTION

7.1 Standard Specifications

Construction materials and procedures should comply with the applicable sections of FHWA FP-14, Standard Specifications for Construction of Road and Bridges on Federal Highway Projects, with the modifications or supplements given below.

Table 7-1: RECOMMENDED MATERIAL SPECIFICATIONS

Materials/Activity FHWA FP-14 Specification Comments

Subgrade Geosynthetics Section 207 Provide a Class 1 Type B nonwoven geotextile according to Table 714-1.

Aggregate Base Section 302 Provide surface course aggregate that meets Grading Designation D or E according to Table 703-2 and Section 703.05(c) requirements.

Cold Plane Pavement Removal Section 413 Traffic may be allowed to travel up to seven days after milling and before the new AC is placed.

Tack Coat Section 412

Asphalt Binder Section 702 Asphalt cement should be PG 64-28.

Asphalt Concrete Pavement Section 403 Place the AC section using a lift thickness between 2 to 3 inches. The ESAL range for the HMA mix design criteria should be <0.3 million.

7.2 Construction Considerations

The pavement sections provided above assume pavement construction will be accomplished during warm, dry conditions and all workmanship and materials will conform to the applicable specifications. In areas requiring full-depth repair during periods of wet weather or when wet-ground conditions exist, it may be necessary to increase the thickness of the AB in order to support construction equipment and protect the potentially moisture-sensitive subgrade soils from disturbance.

Adequate drainage is critical for a well-performing pavement. The design team should verify there is positive drainage in order to move water away from the AB layer. Failure to provide adequate drainage may result in the entrapment of water in the AB layer, which may lead to a reduced pavement life.

8 DESIGN REVIEW AND CONSTRUCTION SERVICES

We welcome the opportunity to review and discuss construction plans and specifications for this project as they are being developed. In addition, GRI should be retained to review all geotechnical-related portions of the plans and specifications to evaluate whether they are in conformance with the recommendations provided in our report and to observe

GRI 6546-A – Ochoco Ranger Station Road Overlay Report Page 7 compliance with the intent of our recommendations, the design concepts, and the plans and specifications. Our construction-phase services will allow for timely design changes if site conditions are encountered that are different from those described in our report. If we do not have the opportunity to confirm our interpretations, assumptions, and analyses during construction, we cannot be responsible for the application of our recommendations to subsurface conditions different from those described in this report.

9 LIMITATIONS

This report has been prepared to aid the project team in the design of this project. The scope is limited to the specific project and location described in this report, and our description of the project represents our understanding of the significant aspects of the project relevant to design and construction on Ochoco Ranger Station Road. In the event that any changes in the design and location of the project elements as outlined in this report are planned, we should be given the opportunity to review the changes and modify or reaffirm the conclusions and recommendations of this report in writing.

The conclusions and recommendations in this report are based on the data obtained from the subsurface explorations at the locations shown on Figure 1 and other sources of information discussed in this report. In the performance of subsurface investigations, specific information is obtained at specific locations at specific times. However, it is acknowledged that variations in subsurface conditions may exist between exploration locations. This report does not reflect variations that may occur between these explorations. The nature and extent of variation may not become evident until construction. If, during construction, subsurface conditions differ from those encountered in the explorations, we should be advised at once so we can observe and review these conditions and reconsider our recommendations where necessary.

Submitted for GRI, Lindsi Hammond, PE Todd Scholz, PhD, PE

Principal Principal

This document has been submitted electronically.

Renews: 06/2023

GRI 6546-A – Ochoco Ranger Station Road Overlay Report Page 8

10 REFERENCES

American Association of State Highway and Transportation Officials (AASHTO), 1993, AASHTO Guide for Design of Pavement Structures, Washington, D.C.

ASTM International, ASTM STP 1375, Third Volume, Tayabji, D., and Lukanen, E.O., Eds., pp.

14-22.

Chen, Jianzhou, Mustaque Hossain, and Todd M. Latorella. "Use of falling weight deflectometer and dynamic cone penetrometer in pavement evaluation."

Transportation Research Record 1655, no. 1 (1999): 145-151.

Soil Survey Staff, 2020, Natural Resources Conservation Service, United States Department of Agriculture, Web soil survey, available online at http://websoilsurvey.nrcs.usda.gov/, accessed 07/10/20.

SITE PLAN

DEC. 2021 JOB NO. 6546-A FIG. 1

Not to Scale

PAVEMENT EXPLORATIONS & DYNAMIC CONE PENETROMETER TESTING

COMPLETED BY GRI (OCTOBER 19, 2021)

PAVEMENT EXPLORATIONS TESTING COMPLETED BY GRI

(OCTOBER 19, 2021)

PROJECT LIMITS

APPENDIX A

Field Explorations and Laboratory Testing

GRI 6546-A – Ochoco Ranger Station Road Overlay Report Page A-1

APPENDIX A

FIELD EXPLORATIONS AND LABORATORY TESTING

A.1 FIELD EXPLORATIONS

A.1.1 General

GRI completed nine pavement cores/shallow borings (B-1 through B-9) within the project limits on October 19, 2021. The approximate locations of the subsurface explorations are shown on Figure 1. We drilled through the pavement surface and advanced the pavement core/boring explorations, referred to as full-depth pavement borings, to a depth of about 5 feet below ground surface (BGS). The field-exploration and laboratory-testing programs completed for this project are described below.

A.1.2 Pavement Core Explorations We conducted nine pavement cores/shallow borings for the purposes of evaluating the type, thickness, and condition of subsurface materials present at the site. GRI completed the pavement core explorations and we retained Custom Hole Drilling, Inc. (CHD) of Molalla, Oregon, to conduct the shallow borings. A GRI representative advanced a 6-inch-diameter, diamond-tipped core drill bit through the bound pavement layers using an electric core drill. CHD advanced the shallow borings into the subgrade soils using solid-stem auger techniques with a Dandy Digger Model 25-30T. An experienced representative of GRI’s engineering staff observed the explorations and maintained logs of the type, thickness, and condition of cores and the materials and conditions encountered during the drilling operations. A summary of pavement thickness and condition at the core locations is provided on Figure 1A. Logs of the pavement boring explorations are provided on Figures 2A through 6A, and photographs of the core locations and core samples are shown on Figures 7A through 15A.

We collected disturbed soil samples at approximately 1-foot intervals of depth within the pavement boring explorations. Our staff examined the soil samples in the field and retained portions of the materials in sample jars for further examination and physical testing in our laboratory. The terms and symbols used to describe the subsurface materials encountered in the explorations are defined in Table 1A.

A.1.3 Dynamic Cone Penetration Tests We completed DCP testing in general accordance with ASTM International (ASTM) D6951 to a depth of about 40 inches BGS using a Kessler dynamic cone penetrometer manufactured by KSE Testing Equipment. We completed the testing at the core locations by driving a ⅝-inch-diameter steel rod with a cone tip into the soil using a 17.6-pound sliding hammer dropped from a fixed height of 22.6 inches. We recorded the number of hammer drops, or blows, required to advance the cone tip at approximately one-inch increments. We used the DCP blow counts to estimate a California bearing ratio (CBR) and

GRI 6546-A – Ochoco Ranger Station Road Overlay Report Page A-2 resilient modulus value for the in-situ subgrade soil at each test location. The Kessler DCP results are shown on Figures 17A and 23A. A summary of the minimum values observed on the figures is provided in Table 2A, below.

Table 2A: DCP SUMMARY TABLE

DCP Test Number Estimated Subgrade Modulus, psi

1 7,470

2 Refusal

3 6,020

4 4,220

5 5,930

6 4,960

7 7,790

8 Refusal

9 15,390

Average Subgrade Modulus, psi 7,397

Standard Deviation 3,745

Coefficient of Variation 51

Design Subgrade Modulus (2.3-percentile value divided by 0.70), psi

6,100

A.2 LABORATORY TESTING

A.2.1 General

We brought all samples obtained from the field-exploration program to our laboratory for examination and testing. We noted the physical characteristics and modified the field classifications where necessary. The laboratory-testing program included determinations of natural moisture contents and performing Atterberg limits on subgrade soil samples.

A.2.2 Natural Moisture Content We determined the natural moisture content in conformance with ASTM International D2216. The results are summarized in Table 2A.

A.2.2 Atterberg Limits We performed an Atterberg-limits test on one subgrade soil sample in conformance with ASTM International D4318. The test result is summarized on the Plasticity Chart, Figure 16A; on Figure 4A; and in Table 2A.

February 28, 2022

Table 1A

GUIDELINES FOR CLASSIFICATION OF SOIL

Description of Relative Density for Granular Soil

Relative Density Standard Penetration Resistance (N-values) blows/foot

Very Loose 0 - 4

Loose 4 - 10

Medium Dense 10 - 30

Dense 30 - 50

Very Dense over 50

Description of Consistency for Fine-Grained (Cohesive) Soils

Consistency

Standard Penetration Resistance (N-values) blows/foot

Torvane or Undrained Shear

Strength, tsf

Very Soft 0 - 2 less than 0.125

Soft 2 - 4 0.125 - 0.25

Medium Stiff 4 - 8 0.25 - 0.50

Stiff 8 - 15 0.50 - 1.0

Very Stiff 15 - 30 1.0 - 2.0

Hard over 30 over 2.0

Grain-Size Classification Modifier for Subclassification

Boulders:

>12 in.

Cobbles:

3-12 in.

Gravel:

¼ - ¾ in. (fine) ¾ - 3 in. (coarse) Sand:

No. 200 - No. 40 sieve (fine) No. 40 - No. 10 sieve (medium) No. 10 - No. 4 sieve (coarse) Silt/Clay:

Pass No. 200 sieve

Adjective

Primary Constituent SAND or GRAVEL

Primary Constituent SILT or CLAY

Percentage of Other Material (By Weight) trace: 5 - 15 (sand, gravel) 5 - 15 (sand, gravel) some: 15 - 30 (sand, gravel) 15 - 30 (sand, gravel) sandy, gravelly: 30 - 50 (sand, gravel) 30 - 50 (sand, gravel) trace: <5 (silt, clay) Relationship of clay and silt determined by plasticity index test some: 5 - 12 (silt, clay) silty, clayey: 12 - 50 (silt, clay)

B-1 S-1 1.0 -- 9 -- -- -- -- GRAVEL

S-2 2.5 -- 9 -- -- -- -- Silty GRAVEL S-3 4.0 -- 31 -- -- -- 45 Silty SAND

S-4 4.5 -- 23 -- -- -- -- SILT

B-2 S-1 1.0 -- 14 -- -- -- -- GRAVEL

S-2 1.5 -- 18 -- -- -- -- Silty GRAVEL S-3 2.5 -- 14 -- -- -- -- Silty GRAVEL S-4 4.5 -- 10 -- -- -- -- Silty GRAVEL

B-3 S-1 1.0 -- 13 -- -- -- -- GRAVEL

S-2 2.0 -- 18 -- -- -- -- CLAY

S-3 4.5 -- 12 -- -- -- -- Silty SAND

B-4 S-1 1.0 -- 11 -- -- -- -- GRAVEL

S-2 2.5 -- 24 -- -- -- -- CLAY

S-3 4.5 -- 21 -- -- -- -- Silty SAND

B-5 S-1 1.0 -- 14 -- -- -- -- GRAVEL

S-2 2.0 -- 23 -- -- -- -- CLAY

S-3 3.0 -- 38 -- 74 45 -- CLAY

S-4 4.5 -- 29 -- 42 15 -- Sandy SILT

B-6 S-1 1.0 -- 6 -- -- -- -- GRAVEL

S-2 2.5 -- 28 -- -- -- -- CLAY

S-3 4.5 -- 20 -- -- -- -- SILT

B-7 S-1 1.0 -- 15 -- -- -- -- GRAVEL

S-2 2.0 -- 10 -- -- -- 25 Silty SAND S-3 4.5 -- 12 -- -- -- -- Silty SAND

B-8 S-1 1.5 -- 4 -- -- -- -- Silty GRAVEL S-2 2.5 -- 11 -- -- -- -- Silty SAND S-3 4.5 -- 11 -- -- -- -- Silty SAND

B-9 S-1 1.0 -- 6 -- -- -- -- GRAVEL

S-2 2.5 -- 26 -- -- -- -- SILT

S-3 3.5 -- 24 -- -- -- -- SILT

S-4 4.5 -- 15 -- -- -- -- Gravelly SILT

Table 3A

SUMMARY OF LABORATORY RESULTS

Sample Information Atterberg Limits

Soil Type Fines

Content, % Plasticity Index, %

Liquid Limit, %

Dry Unit Weight, pcf

Moisture Content, %Elevation, ftSampleLocation Depth, ft

PAVEMENT CORE SUMMARY

DEC. 2021 JOB NO. 6546-A FIG. 1A

Abbreviations: AC = Asphalt Concrete; C = Core; EB = Eastbound; WB = Westbound; OWT = Outer Wheelpath

Abbreviations: Dir = Direction; Loc = Location; STA = Station

GRAVEL; clean to some silt, clay, and sand

Sandy GRAVEL; clean to some silt and clay

Silty GRAVEL; up to some clay and sand

Clayey SAND; up to some silt and gravel

Gravelly CLAY; up to some silt and sand

Sandy CLAY; up to some silt and gravel

Silty CLAY; up to some sand and gravel

Symbol Description

Flush-mount monument set in concrete

Concrete, well casing shown where applicable

Filter pack, machine-slotted well casing shown where applicable

1-in.-diameter solid PVC

FIELD MEASUREMENTS

Typical Description

Groundwater level after drilling and date measured

Symbol Typical Description

BASALT

MUDSTONE

SILTSTONE

PEAT

Symbol

FILL

Clayey GRAVEL; up to some silt and sand

SAND; clean to some silt, clay, and gravel

SILT; up to some clay, sand, and gravel

Gravelly SILT; up to some clay and sand

Sandy SILT; up to some clay and gravel

Clayey SILT; up to some sand and gravel

CLAY; up to some silt, sand, and gravel

Grab Sample

Rock core sample interval

Sonic core sample interval

INSTALLATION SYMBOLS

Symbol

Bentonite seal, well casing shown if applicable

Vibrating-wire pressure transducer

SymbolBEDROCK SYMBOLS

SOIL SYMBOLS

Typical Description

SAMPLER SYMBOLS

Sampler DescriptionSymbol

LANDSCAPE MATERIALS

Gravelly SAND; clean to some silt and clay

Silty SAND; up to some clay and gravel

Shelby tube sampler with recovery

(ASTM D1587)

Grout, vibrating-wire transducer cable shown where applicable

1-in.-diameter hand-slotted PVC

Grout, inclinometer casing shown where applicable

Groundwater level during drilling and date measured

SANDSTONE

SURFACE MATERIAL SYMBOLS

Symbol Typical Description

BORING AND TEST PIT LOG LEGEND

Rock quality designation (RQD, %)

Asphalt concrete PAVEMENT

Portland cement concrete PAVEMENT

Crushed rock BASE COURSE

2.0 in. O.D. split-spoon sampler and Standard Penetration Test with recovery (ASTM D1586)

3.0 in. O.D. split-spoon sampler with recovery

(ASTM D3550)

Push probe sample interval

Rock/sonic core or push probe recovery (%)

B O

R

IN

G A

N D

T E

S T

P

IT

L O

G L

E G

E N

D G

R I D

A T

A T

E M

P

LA

T E

.G D

T

2/ 9/

ASPHALT CONCRETE (8 inches) over OIL MAT (1 inch) over AGGREGATE BASE (12 inches)

Silty GRAVEL, some sand, dark brown, moist, medium dense

Silty SAND, light gray, moist, medium dense SILT, some gravel, some sand, dark brown, moist, stiff (10/19/2021)

Date Started:

Excavated by: Equipment:

Note:

TORVANE SHEAR STRENGTH, TSF

0.50

J. HeidgerkenLogged By:

1.0

10/19/21 Custom Hole Drilling, Inc. Dandy Digger 25-30T

See Legend for Explanation of Symbols

B-1 Surface Elevation: Not Available

GPS Coordinates: Not Available

SA

M

PL

E

N O

G R

AP

H

IC

L

O G

EL

EV

AT

IO

N , F

T D

EP

TH

, F T

D

EP

TH

, F

T

COMMENTS AND

ADDITIONAL TESTS

SA

M

PL

E

TY

PECLASSIFICATION OF MATERIAL

PLASTIC LIMIT, %

LIQUID LIMIT, %

FINES CONTENT, %

MOISTURE CONTENT, %

FIG. 2A

BORINGS

G R

I H A

L O

G

G P

S

P P

G R

I D A

T A

T E

M P

LA

T

E .G

D T

2/

9/

ASPHALT CONCRETE (8-1/2 inches) over OIL MAT (1-1/2 inches) over AGGREGATE BASE (8 inches)

Silty GRAVEL, some sand, gray, moist, medium dense to dense --- gray-brown at 2-1/2 feet

--- medium dense at 4 feet

(10/19/2021)

Date Started:

Excavated by: Equipment:

Note:

TORVANE SHEAR STRENGTH, TSF

0.50

J. HeidgerkenLogged By:

1.0

10/19/21 Custom Hole Drilling, Inc. Dandy Digger 25-30T

See Legend for Explanation of Symbols

B-2 Surface Elevation: Not Available

GPS Coordinates: Not Available

S-1

S-2

S-3 S-4

1.7

4.0 4.5 5.05

DEC. 2021 JOB NO. 6546-A

S-1 S-2

S-3

S-4

1.5

5.05

0 100

0 100

ASPHALT CONCRETE (7-1/2 inches) over OIL MAT (1-1/2 inches) over AGGREGATE BASE (11 inches)

CLAY, some gravel, trace sand, dark brown to gray, moist, stiff

Silty SAND, some gravel, brown, moist, medium dense

(10/19/2021)

Date Started:

Excavated by: Equipment:

Note:

TORVANE SHEAR STRENGTH, TSF

0.50

J. HeidgerkenLogged By:

1.0

10/19/21 Custom Hole Drilling, Inc. Dandy Digger 25-30T

See Legend for Explanation of Symbols

B-3 Surface Elevation: Not Available

GPS Coordinates: Not Available

SA

M

PL

E

N O

G R

AP

H

IC

L

O G

EL

EV

AT

IO

N , F

T D

EP

TH

, F T

D

EP

TH

, F

T

COMMENTS AND

ADDITIONAL TESTS

SA

M

PL

E

TY

PECLASSIFICATION OF MATERIAL

PLASTIC LIMIT, %

LIQUID LIMIT, %

FINES CONTENT, %

MOISTURE CONTENT, %

FIG. 3A

BORINGS

G R

I H A

L O

G

G P

S

P P

G R

I D A

T A

T E

M P

LA

T

E .G

D T

2/

9/

ASPHALT CONCRETE (7-1/2 inches) over OIL MAT (1-1/2 inch) over AGGREGATE BASE (13 inches)

CLAY, some sand and gravel, brown to dark brown, moist, stiff

Silty SAND, some gravel, light brown, moist, medium dense

(10/19/2021)

Date Started:

Excavated by: Equipment:

Note:

TORVANE SHEAR STRENGTH, TSF

0.50

J. HeidgerkenLogged By:

1.0

10/19/21 Custom Hole Drilling, Inc. Dandy Digger 25-30T

See Legend for Explanation of Symbols

B-4 Surface Elevation: Not Available

GPS Coordinates: Not Available

S-1

S-2

S-3

1.7

3.5

5.05

DEC. 2021 JOB NO. 6546-A

S-1

S-2

S-3

1.8

3.5

5.05

0 100

0 100

ASPHALT CONCRETE (8-1/2 inches) over OIL MAT (2-1/2 inches) over AGGREGATE BASE (9 inches)

CLAY, some gravel, trace sand, dark gray, moist, stiff

--- light brown, gravel absent at 3 feet

Sandy SILT to silty SAND, light brown, moist, medium stiff or loose

(10/19/2021)

Date Started:

Excavated by: Equipment:

Note:

TORVANE SHEAR STRENGTH, TSF

0.50

J. HeidgerkenLogged By:

1.0

10/19/21 Custom Hole Drilling, Inc. Dandy Digger 25-30T

See Legend for Explanation of Symbols

B-5 Surface Elevation: Not Available

GPS Coordinates: Not Available

SA

M

PL

E

N O

G R

AP

H

IC

L

O G

EL

EV

AT

IO

N , F

T D

EP

TH

, F T

D

EP

TH

, F

T

COMMENTS AND

ADDITIONAL TESTS

SA

M

PL

E

TY

PECLASSIFICATION OF MATERIAL

PLASTIC LIMIT, %

LIQUID LIMIT, %

FINES CONTENT, %

MOISTURE CONTENT, %

FIG. 4A

BORINGS

G R

I H A

L O

G

G P

S

P P

G R

I D A

T A

T E

M P

LA

T

E .G

D T

2/

9/

ASPHALT CONCRETE (6-1/2 inches) over AGGREGATE BASE (14-1/2 inches)

CLAY, trace sand and gravel, light brown to orange, moist, medium stiff to stiff

SILT, some gravel, trace sand, dark gray, moist, medium stiff (10/19/2021)

Date Started:

Excavated by: Equipment:

Note:

TORVANE SHEAR STRENGTH, TSF

0.50

J. HeidgerkenLogged By:

1.0

10/19/21 Custom Hole Drilling, Inc. Dandy Digger 25-30T

See Legend for Explanation of Symbols

B-6 Surface Elevation: Not Available

GPS Coordinates: Not Available

S-1

S-2

S-3

S-4

1.7

3.5

5.05

DEC. 2021 JOB NO. 6546-A

S-1

S-2

S-3

1.8

4.5 5.05

0 100

0 100

ASPHALT CONCRETE (8-3/4 inches) over OIL MAT (2-1/2 inches) over AGGREGATE BASE (7-3/4 inches)

Silty SAND, some gravel, light brown, moist, medium dense

(10/19/2021)

Date Started:

Excavated by: Equipment:

Note:

TORVANE SHEAR STRENGTH, TSF

0.50

J. HeidgerkenLogged By:

1.0

10/19/21 Custom Hole Drilling, Inc. Dandy Digger 25-30T

See Legend for Explanation of Symbols

B-7 Surface Elevation: Not Available

GPS Coordinates: Not Available

SA

M

PL

E

N O

G R

AP

H

IC

L

O G

EL

EV

AT

IO

N , F

T D

EP

TH

, F T

D

EP

TH

, F

T

COMMENTS AND

ADDITIONAL TESTS

SA

M

PL

E

TY

PECLASSIFICATION OF MATERIAL

PLASTIC LIMIT, %

LIQUID LIMIT, %

FINES CONTENT, %

MOISTURE CONTENT, %

FIG. 5A

BORINGS

G R

I H A

L O

G

G P

S

P P

G R

I D A

T A

T E

M P

LA

T

E .G

D T

2/

9/

ASPHALT CONCRETE (7-3/4 inches) over OIL MAT (2-1/4 inches) over AGGREGATE BASE (5 inches) Silty GRAVEL, some sand, light brown to brown, moist, dense --- contains cobbles from 1-1/4 feet to 2-1/2 feet Silty SAND, some gravel, brown, moist, medium dense --- trace gravel, light brown at 3-1/2 feet

(10/19/2021)

Date Started:

Excavated by: Equipment:

Note:

TORVANE SHEAR STRENGTH, TSF

0.50

J. HeidgerkenLogged By:

1.0

10/19/21 Custom Hole Drilling, Inc. Dandy Digger 25-30T

See Legend for Explanation of Symbols

B-8 Surface Elevation: Not Available

GPS Coordinates: Not Available

S-1

S-2

S-3

1.5

5.05

DEC. 2021 JOB NO. 6546-A

S-1

S-2

S-3

1.3

2.5

5.05

0 100

0 100

ASPHALT CONCRETE (7 inches) over OIL MAT (2-1/2 inches) over AGGREGATE BASE (12-1/2 inches)

SILT, some sand, trace gravel, dark brown, moist, medium stiff

--- some gravel at 3-1/2 feet

--- gravelly at 4-1/2 feet

(10/19/2021)

Date Started:

Excavated by: Equipment:

Note:

TORVANE SHEAR STRENGTH, TSF

0.50

J. HeidgerkenLogged By:

1.0

10/19/21 Custom Hole Drilling, Inc. Dandy Digger 25-30T

See Legend for Explanation of Symbols

B-9 Surface Elevation: Not Available

GPS Coordinates: Not Available

SA

M

PL

E

N O

G R

AP

H

IC

L

O G

EL

EV

AT

IO

N , F

T D

EP

TH

, F T

D

EP

TH

, F

T

COMMENTS AND

ADDITIONAL TESTS

SA

M

PL

E

TY

PECLASSIFICATION OF MATERIAL

PLASTIC LIMIT, %

LIQUID LIMIT, %

FINES CONTENT, %

MOISTURE CONTENT, %

FIG. 6A

BORINGS

G R

I H A

L O

G

G P

S

P P

G R

I D A

T A

T E

M P

LA

T

E .G

D T

2/

9/

S-1

S-2

S-3

S-4

1.8

5.05

DEC. 2021 JOB NO. 6546-A

0 100

Core B-1 Location

Core B-1 Sample

PAVEMENT CORE PHOTOGRAPHS

DEC. 2021 JOB NO. 6546-A FIG. 7A

Core B-2 Location

Core B-2 Sample

DEC. 2021 JOB NO. 6546-A FIG. 8A

Core B-3 Location

Core B-3 Sample

DEC. 2021 JOB NO. 6546-A FIG. 9A

Core B-4 Location

Core B-4 Sample

DEC. 2021 JOB NO. 6546-A FIG. 10A

Core B-5 Location

Core B-5 Sample

DEC. 2021 JOB NO. 6546-A FIG. 11A

Core B-6 Location

Core B-6 Sample

DEC. 2021 JOB NO. 6546-A FIG. 12A

DEC. 2021 JOB NO. 6546-A FIG. 13A

Core B-7 Location

Core B-7 Sample

Core B-8 Location

Core B-8 Sample

OCHOCO ROAD

OVERLAY

PAVEMENT EVALUATION

DEC. 2021 JOB NO. 6546-A FIG. 14A

Core B-9 Location

Core B-9 Sample

DEC. 2021 JOB NO. 6546-A FIG. 15A

0 10 20 30 40 50 60 70 80 90 100

S-3

S-4

3.0

4.5

CLAY, trace sand, light brown

Sandy SILT to silty SAND, light brown

Classification PL

Sample MC, %

PL

A

ST

IC

IT

Y

IN

D

EX

LIQUID LIMIT, %

Location Depth, ft

PLASTICITY CHART

B-5

B-5

LL PI

OL

ML

CL

INORGANIC CLAYEY SILTS TO VERY FINE

SANDS OF SLIGHT PLASTICITY

INORGANIC CLAYS OF HIGH PLASTICITY

UNIFIED SOIL CLASSIFICATION

FINE-GRAINED SOIL GROUPS

GROUP

SYMBOL

GROUP

SYMBOL

OH

MH

CH

ORGANIC SILTS AND ORGANIC SILTY

CLAYS OF LOW PLASTICITY

A T

T E

R B

E R

G -P

LA

S

T

IC

IT

Y

P

E R

P A

G E

G R

I D A

T A

T E

M P

LA

T

E .G

D T

2/

9/

CH

CL

MH or OH

CL-ML

ML or OL

INORGANIC CLAYS OF LOW TO MEDIUM

PLASTICITY

ORGANIC CLAYS OF MEDIUM TO HIGH

PLASTICITY, ORGANIC SILTS

INORGANIC SILTS AND CLAYEY SILT

UNIFIED SOIL CLASSIFICATION

FINE-GRAINED SOIL GROUPS

JOB NO. 6546-ADEC. 2021 FIG. 16A

JOB NO.: 6546-A DRAWN BY: JGH

DCP-1 Surface Type Subgrade

Ochoco Ranger Station Road Hammer 17.6 pounds

0.0 0 0 ---

0.7 18 1 0.06

1.2 31 3 0.15

1.9 47 8 0.31

2.8 70 13 0.22

3.9 100 18 0.17

5.0 127 21 0.11

6.5 164 24 0.08

8.6 219 27 0.05

10.2 258 30 0.08

11.3 286 33 0.11

11.9 303 36 0.18

12.4 316 39 0.23

13.2 336 42 0.15

14.7 373 45 0.08

DEC. 2021 JOB NO.6546-A FIG. 17A

DYNAMIC CONE PENETROMETER

Location

Depth, inches Depth, millimeters Cumulative Blows Slope

Test Number

KESSLER DYNAMIC CONE PENETROMETER LOG

TESTING DATE: 10/19/2021

Resilient Modulus ~7,470 pounds per square inch

0 50

Cu m ul at iv e

Pe ne tr at io n

(m m

Cumulative Blows

DCP-1

DCP-3 Surface Type Subgrade

Ochoco Ranger Station Road Hammer 17.6 pounds

0.0 0 0 ---

0.8 21 1 0.05

1.7 43 2 0.05

2.0 52 3 0.11

2.4 61 4 0.11

2.9 73 5 0.08

3.6 91 7 0.11

5.1 129 9 0.05

6.7 170 11 0.05

8.5 216 13 0.04

9.3 236 15 0.10

9.9 251 17 0.13

10.7 273 19 0.09

12.2 309 21 0.06

DEC. 2021 JOB NO.6546-A FIG. 18A

Test Number

KESSLER DYNAMIC CONE PENETROMETER LOG

TESTING DATE: 10/19/2021

Location

Depth, inches Depth, millimeters Cumulative Blows Slope

DYNAMIC CONE PENETROMETER

Resilient Modulus ~6,020 pounds per square inch

0 50

Cu m ul at iv e

Pe ne tr at io n

(m m

DCP-3

DCP-4 Surface Type Subgrade

Ochoco Ranger Station Road Hammer 17.6 pounds

0.0 0 0 ---

1.8 45 1 0.02

3.5 88 2 0.02

4.9 124 3 0.03

6.1 154 4 0.03

7.2 182 5 0.04

DEC. 2021 JOB NO.6546-A FIG. 19A

Test Number

KESSLER DYNAMIC CONE PENETROMETER LOG

TESTING DATE: 10/19/2021

Location

Depth, inches Depth, millimeters Cumulative Blows Slope

DYNAMIC CONE PENETROMETER

Resilient Modulus ~4,220 pounds per square inch

0 50

Cu m ul at iv e

Pe ne tr at io n

(m m

DCP-4

DCP-5 Surface Type Subgrade

Ochoco Ranger Station Road Hammer 17.6 pounds

0.0 0 0 ---

2.0 50 3 0.06

3.1 80 6 0.10

4.4 112 10 0.13

5.6 143 20 0.32

7.1 180 30 0.27

8.7 220 42 0.30

9.7 246 49 0.27

10.2 258 51 0.17

10.7 271 53 0.15

11.8 299 55 0.07

13.1 332 57 0.06

DEC. 2021 JOB NO.6546-A FIG. 20A

DYNAMIC CONE PENETROMETER

Location

Depth, inches Depth, millimeters Cumulative Blows Slope

Test Number

KESSLER DYNAMIC CONE PENETROMETER LOG

TESTING DATE: 10/19/2021

Resilient Modulus ~5,930 pounds per square inch

Resilient Modulus ~6,740 pounds per square inch

Resilient Modulus ~10,380 pounds per square inch

0 50 100

Cu m ul at iv e

Pe ne tr at io n

(m m

Cumulative Blows

DCP-5

Equivalent subgrade resilient modulus ~8,180 pounds per square inch based on Odemark's Method of Equivalent Thickness

DCP-6 Surface Type Subgrade

Ochoco Ranger Station Road Hammer 17.6 pounds

0.0 0 1 ---

0.8 21 2 0.05

1.7 43 3 0.05

2.7 69 4 0.04

3.8 97 5 0.04

4.9 124 6 0.04

5.9 149 7 0.04

6.8 173 8 0.04

7.8 197 9 0.04

8.7 222 10 0.04

9.5 241 11 0.05

10.1 257 12 0.06

11.2 284 13 0.04

DEC. 2021 JOB NO.6546-A FIG. 21A

Test Number

KESSLER DYNAMIC CONE PENETROMETER LOG

TESTING DATE: 10/19/2021

Location

Depth, inches Depth, millimeters Cumulative Blows Slope

DYNAMIC CONE PENETROMETER

Resilient Modulus ~4,960 pounds per square inch

0 50

Cu m ul at iv e

Pe ne tr at io n

(m m

DCP-6

DCP-7 Surface Type Subgrade

Ochoco Ranger Station Road Hammer 17.6 pounds

0.0 0 0 ---

0.7 18 1 0.06

1.2 30 6 0.42

1.6 41 11 0.45

2.0 50 16 0.56

2.6 67 21 0.29

3.4 87 26 0.25

4.5 114 31 0.19

5.7 146 36 0.16

6.6 167 41 0.24

7.4 189 46 0.23

8.5 217 51 0.18

9.9 251 56 0.15

10.9 278 59 0.11

12.0 306 62 0.11

13.1 332 65 0.12

13.9 354 68 0.14

14.5 368 71 0.21

15.2 385 74 0.18

DEC. 2021 JOB NO.6546-A FIG. 22A

DYNAMIC CONE PENETROMETER

Location

Depth, inches Depth, millimeters Cumulative Blows Slope

Test Number

KESSLER DYNAMIC CONE PENETROMETER LOG

TESTING DATE: 10/19/2021

Resilient Modulus ~7,790 pounds per square inch

Resilient Modulus ~11,550 pounds per square inch

Resilient Modulus ~9,280 pounds per square inch

0 50 100

Cu m ul at iv e

Pe ne tr at io n

(m m

Cumulative Blows

DCP-7

Equivalent subgrade resilient modulus ~8,480 pounds per square inch based on Odemark's Method of Equivalent Thickness

DCP-9 Surface Type Subgrade

Ochoco Ranger Station Road Hammer 17.6 pounds

0.0 0 0 ---

0.7 18 10 0.56

1.4 36 25 0.83

2.1 54 40 0.83

3.2 81 55 0.56

4.3 109 65 0.36

5.5 140 75 0.32

6.6 167 85 0.37

7.1 181 95 0.71

DEC. 2021 JOB NO.6546-A FIG. 23A

DYNAMIC CONE PENETROMETER

Location

Depth, inches Depth, millimeters Cumulative Blows Slope

Test Number

KESSLER DYNAMIC CONE PENETROMETER LOG

TESTING DATE: 10/19/2021

Resilient Modulus ~15,380 pounds per square inch

Resilient Modulus ~12,080 pounds per square inch

0 50 100 150

Cu m ul at iv e

Pe ne tr at io n

(m m

Cumulative Blows

DCP-9

Equivalent subgrade resilient modulus ~13,010 pounds per square inch based on Odemark's Method of Equivalent Thickness

APPENDIX B

Ground-Penetrating Radar

GRI 6546-A – Ochoco Ranger Station Road Overlay Report Page B-1

APPENDIX B

GROUND-PENETRATING RADAR

B.1 GENERAL

We conducted a ground-penetrating radar (GPR) survey of Ochoco Ranger Station Road in order to determine the pavement surfacing thickness and identity potential delamination in the asphalt layers between the project limits.

B.2 BACKGROUND

GPR is a geophysical technique used for detecting subsurface features such as rebar in concrete, pavement-surfacing thickness, soil strata boundaries and bedrock depth, and underground storage tanks and utilities. Our GPR system transmits high-frequency electromagnetic pulses (waveforms) into the ground and records the time between transmission and receipt of the waveforms reflected from buried features or from stratigraphic boundaries. Reflections of the waveforms occur at boundaries of electrically dissimilar materials, such as at the interface between aggregate backfill and the top of a metal pipe. More specifically, reflections of the transmitted pulse occur at locations where a change in dielectric permittivity occurs. In simplified terms, dielectric permittivity is a unitless measure of the capacity of a material to hold an electric charge when exposed to an electric field. Given that dielectric permittivity varies among materials, it was normalized to air through the dielectric constant, where the constant for air has been defined as unity (one). Materials that are denser than air and/or contain moisture have a dielectric constant greater than air. Given that the dielectric constant of a given material is directly related to the velocity of the electromagnetic pulse traveling through the material, the dielectric constant is used to relate time of waveform travel through the material to the depth (distance) at which a reflection occurs. In this way, and based on the chosen or assumed dielectric constant, GPR data can be used to estimate the depth at which waveforms are reflected off subsurface features.

B.3 GPR DATA COLLECTION

We conducted a longitudinal GPR survey along the roadway segment (i.e., parallel to the roadway centerline) for the purposes of estimating pavement surfacing depth and depths to potential delamination interfaces. We conducted the survey using a 2-GHz, truck-mounted horn antenna, Model 42000S, manufactured by Geophysical Survey Systems, Inc.

(GSSI) along the outside wheel tracks of the travel lanes in each direction on October 19, 2021.

B.4 DATA PROCESSING AND RESULTS

We analyzed the GPR data using RADAN 7 to identify pavement-surfacing depths and depths to potential delamination interfaces. We adjusted the depths to ground-truth

GRI 6546-A – Ochoco Ranger Station Road Overlay Report Page B-2 information obtained from the pavement cores (i.e., pavement surfacing thickness and delamination depths, when present, at core locations) to account for differences between the assumed dielectric constant used during data collection and calculated dielectric constant based on actual depths to reflections. A summary of the results is presented on Figures 1B through 3B in this appendix, which shows the estimated pavement-surfacing depths and depth to delamination interface along the alignment.

GPR

STA 825+00 TO 1025+00

DEC. 2021 JOB NO. 6546-A FIG. 1B

Abbreviations: AC = Asphalt Concrete; STA = Station

STA 1025+00 TO 1175+00

DEC. 2021 JOB NO. 6546-A FIG. 2B

STA 1175+00 TO 1315+00

DEC. 2021 JOB NO. 6546-A FIG. 3B

APPENDIX C

Pavement Design Analysis

GRI 6546-A – Ochoco Ranger Station Road Overlay Report Page C-1

APPENDIX C

PAVEMENT DESIGN ANALYSIS

C.1 GENERAL

We used the guidance and methodologies presented in the 1993 AASHTO Guide for Design of Pavement Structures (1993 AASHTO Guide) to develop pavement designs for rehabilitation and full-depth repair with reconstruction. Our traffic-loading approximations are based on the truck volumes’ data provided in the 2018 FLAP application. Details of our traffic-loading analysis are provided in Table 1C in this appendix.

Pavement design parameters used to the design pavement structure for a 20-year design period are shown in the flexible pavement design worksheets (Tables 2C through 4C) in this appendix.

C.2 REFERENCE

American Association of State Highway and Transportation Officials (AASHTO), 1993, AASHTO guide for design of pavement structures, Washington, D.C.

Table 1C - 20-YEAR TRAFFIC LOADING ANALYSIS

Information from 2018 Oregon FLAP Application 2018 Average Daily Traffic

(ADT)

North End of Project 1281 Total Percent Trucks 3% Total Number of Trucks 38

Traffic Loading Analysis Design Period, yrs: 20

(1) (2) (3) (4) (5) FHWA % No. of Total Truck

Truck Class Trucks Trucks/day LEF 20-Yr Design Period Class 5 75.0% 29 104 59,280 Class 6 22.5% 9 284 48,564 Class 9 2.5% 1 466 8,854

Totals 116,698

20 Year Design Traffic Loading, ESALs: 117,000

(1) Information regarding the FHWA truck classification distribution was not provided. Based on our observation during a site visit, and the 2018 FLAP application we selected the distribution of trucks shown above.

(2) No. of trucks/day = % trucks (from column (2))* approximated ADT total number of trucks

(4) LEF = load equivalency factor (i.e. number of equivalent 18-kip single axle loads, ESALs, per truck), based on ODOT.

(5) 20-Yr Traffic = No. of trucks/day * LEF * 20-years

Table 2C - PAVEMENT DESIGN WORKSHEET

REHABILITATION WITH AC OVERLAY

Flexible Pavement Overlay Design Project Segment: Ochoco Ranger Station Road

AASHTO Design Parameters: Notes Design Period, Yrs: 20 Denotes user data field

Cumulative ESAL Repetitions: 117,000 Denotes calculated field Design Reliability: 80 per ODOT Pavement Design Guide

Overall Standard Deviation, So: 0.5 per ODOT Pavement Design Guide Initial Serviceability, Po: 4.2 per ODOT Pavement Design Guide

Terminal Serviceability, Pt: 2.5 per ODOT Pavement Design Guide New AC Layer Coefficient: 0.5 per ODOT Pavement Design Guide

Existing Pavement Conditions:

Average Existing AC/Oil Mat Thickness, inches: 9.50

Average Layer Coefficient of Existing Asphalt Concrete (AC)/Oil Mat: 0.32 based on surface condition & AASHTO 93 Part III Table 5.2 Aggregate Base Course (AB), inches: 10.00

Average Modulus of Base Material below AC, psi: 17,000 based on layer coefficient & AASHTO 93 Part II Figure 2.6 Average Layer Coefficient of AB Material: 0.08 based on surface condition & AASHTO 93 Part III Table 5.2

Estimated SNeff: 3.03 based on core results Subgrade Mr, psi: 6,100 based on DCP results

Calculated Values:

Subgrade Mr, psi: 6,100

Total SN required above subgrade: 2.48 Total SN Deficiency: -0.54

AC SN required above base layer: 1.66 Effective AC SN: 3.03

AC SN Deficiency: -1.37 AC Thickness Deficiency, inches: -1.09

Overlay Design:

Thickness, in.

Layer Coeff. SN

AC overlay above existing pavement surface: 2.00 0.50 1.00 AC inlay below existing pavement surface: 0.00 0.50 0.00

Existing AC removed by inlay: 0.00 0.318421 0 Existing AB removed by inlay: 0.00 0.08 0 Net SN above existing base : 4.03 >1.66 required above base - OK

Net Total SN: 4.03 >2.48 required above subgrade - OK

Table 3C - PAVEMENT DESIGN WORKSHEET

REHABILITATION WITH AC MILL AND INLAY

Flexible Pavement Mill and Inlay Design Project Segment: Ochoco Ranger Station Road

AASHTO Design Parameters: Notes Design Period, Yrs: 20 Denotes user data field

Cumulative ESAL Repetitions: 117,000 Denotes calculated field Design Reliability: 80 per ODOT Pavement Design Guide

Overall Standard Deviation, So: 0.5 per ODOT Pavement Design Guide Initial Serviceability, Po: 4.2 per ODOT Pavement Design Guide

Terminal Serviceability, Pt: 2.5 per ODOT Pavement Design Guide New AC Layer Coefficient: 0.5 per ODOT Pavement Design Guide

Existing Pavement Conditions:

Average Existing AC/Oil Mat Thickness, inches: 9.50

Average Layer Coefficient of Existing Asphalt Concrete (AC)/Oil Mat: 0.32 based on surface condition & AASHTO 93 Part III Table 5.2 Aggregate Base Course (AB), inches: 10.00

Average Modulus of Base Material below AC, psi: 17,000 based on layer coefficient & AASHTO 93 Part II Figure 2.6 Average Layer Coefficient of AB Material: 0.08 based on surface condition & AASHTO 93 Part III Table 5.2

Estimated SNeff: 3.03 based on core results Subgrade Mr, psi: 6,100 based on DCP results

Calculated Values:

Subgrade Mr, psi: 6,100

Total SN required above subgrade: 2.48 Total SN Deficiency: -0.54

AC SN required above base layer: 1.66 Effective AC SN: 3.03

AC SN Deficiency: -1.37 AC Thickness Deficiency, inches: -1.09

Overlay Design:

Thickness, in.

Layer Coeff. SN

AC overlay above existing pavement surface: 0.00 0.50 0.00 AC inlay below existing pavement surface: 3.00 0.50 1.50

Existing AC removed by inlay: 3.00 0.318421 -0.96 Existing AB removed by inlay: 0.00 0.08 0 Net SN above existing base : 3.57 >1.66 required above base - OK

Net Total SN: 3.57 >2.48 required above subgrade - OK

Table 4C- PAVEMENT DESIGN WORKSHEET

FULL-DEPTH REPAIR WITH AGGREGATE STABILIZATION AND GEOTEXTILE

AASHTO Design Parameters & Input Values: Notes Design Period, Years: 20

Cumulative ESAL Repetitions: 117,000 Design Reliability: 85 per ODOT Pavement Design Guide

Overall Standard Deviation, So: 0.5 per ODOT Pavement Design Guide Initial Serviceability, Po: 4.2 per ODOT Pavement Design Guide

Terminal Serviceability, Pt: 2.5 per ODOT Pavement Design Guide Effective Subgrade MR, psi: 6,100 Design Modulus Based on DCP

Aggregate Subbase (ASB) Modulus, psi: 14,741 computed by Dorman & Metcalf formula Aggregate Base (AB) Modulus, psi: 20,000 per ODOT Pavement Design Guide

Asphalt Concrete (AC) Layer Coefficient: 0.42 per ODOT Pavement Design Guide AB Layer Coefficient: 0.10 per ODOT Pavement Design Guide

ASB Layer Coefficient: 0.08 per AASHTO Guide relationship (limited to max of 0.08) AB/ASB Drainage Coefficient: 1.0 per ODOT Pavement Design Guide

10.0

SN required above subgrade: 2.58 SN required above ASB: 1.83 SN required above AB: 1.61

Pavement Section

Layer Description Thickness, inches Layer

Coefficient SN

SN

Subtotals Notes Level 2, 1/2-inch Dense HMAC 3.00 0.42 1.26 PG 64-28 Level 2, 1/2-inch Dense HMAC 3.00 0.42 1.26 2.52 >1.61 required above AB - OK PG 64-28 1-inch-0 or 3/4-inch-0 CSBC 10.00 0.10 1.00 3.52 >1.83 required above ASB - OK 1.5-inch-0 Ballast Subbase 0.00 0.08 0.00 3.52 >2.58 required above subgrade - OK Geotextile NA Total Depth 16.00

Denotes user data field Denotes calculated field

Minimum ASB thickness on geotextile for support of construction, in.: per Giroud & Han procedure