GEOTECHNICAL_EVALUATION_AND_PAVEMENT_DESIGN_REPORT.pdf

20155113/TUL15R24734-REV Page i of iv August 14, 2015 © 2015 Kleinfelder

GEOTECHNICAL EVALUATION

AND PAVEMENT DESIGN REPORT

OK FLAP MEDICINE PARK TRAIL

SH 49 WIDENING AND RESURFACING

COMANCHE COUNTY, OKLAHOMA

FEDERAL HIGHWAY ADMINISTRATION

CENTRAL FEDERAL LANDS HIGHWAY DIVISION

TASK ORDER NUMBER: DTFH68-12-D-00013/0052

AUGUST 14, 2015

Copyright 2015 Kleinfelder All Rights Reserved

ONLY THE CLIENT OR ITS DESIGNATED REPRESENTATIVES MAY USE THIS DOCUMENT AND ONLY FOR THE SPECIFIC

PROJECT FOR WHICH THIS REPORT WAS PREPARED.

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TABLE OF CONTENTS

SECTION PAGE

1 INTRODUCTION

1.1 PURPOSE AND OBJECTIVE

1.2 SCOPE OF SERVICES

1.3 PROJECT LOCATION AND DESCRIPTION

2 GEOLOGY

2.1 GEOLOGY

3 GEOTECHNICAL EXPLORATIONS

3.1 GENERAL

3.2 FIELD EXPLORATIONS

3.2.1 Borings

3.2.2 Sampling and Classification

4 LABORATORY RESULTS

4.1 GEOTECHNICAL LABORATORY TESTING

5 SUBSURFACE CONDITIONS

5.1 PAVEMENT BORINGS

5.2 CUT SECTION BORINGS

5.3 EMBANKMENT BORINGS

5.4 GROUNDWATER

6 PAVEMENT DESIGN, PAVEMENT MATERIALS, AND CONSTRUCTION

CONSIDERATIONS

6.1 PAVEMENT DESIGN

6.1.1 Subgrade Materials and Strength

6.1.2 Pavement Distress Survey

6.1.3 Traffic Information

6.1.4 Design Sections

6.2 PAVEMENT MATERIALS

6.2.1 Asphalt Mix

6.2.2 Crushed Aggregate Base Course

6.2.3 Milling, Crack Sealing and Overlay

6.2.4 Tack and Prime Coat

6.3 CONSTRUCTION CONSIDERATIONS

6.3.1 Subgrade Preparation

6.3.2 Drainage

6.3.3 Pavement Maintenance

7 ROADWAY WIDENING

7.1 GENERAL

7.2 SLOPE STABILITY SHEAR STRENGTH PARAMETERS

7.3 SUMMARY OF SLOPE STABILITY RESULTS

7.4 CONSTRUCTION CONSIDERATIONS

7.4.1 Excavation Characteristics

7.4.2 Structural Fill

7.4.3 Compaction Requirements

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7.4.4 Construction in Wet or Cold Weather

8 ADDITIONAL SERVICES

9 LIMITATIONS

10 REFERENCES

11 ACRONYMS DEFINED

FIGURES

1 Site Location Diagram 2 to 9 Boring Location Diagram(s)

APPENDICES

A Site Location Diagram and Boring Location Diagram B Boring Logs C Geotechnical Laboratory Testing Results D Slope Stability Analyses Results E DARWin Analyses F Rock Core Pictures

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GEOTECHNICAL EVALUATION

AND PAVEMENT DESIGN REPORT

OK FLAP MEDICINE PARK TRAIL

SH 49 WIDENING AND RESURFACING

COMANCHE COUNTY, OKLAHOMA

FEDERAL HIGHWAY ADMINISTRATION

CENTRAL FEDERAL LANDS HIGHWAY DIVISION

TASK ORDER NUMBER: DTFH68-12-D-00013/0052

1 INTRODUCTION

1.1 PURPOSE AND OBJECTIVE

Kleinfelder, Inc. (Kleinfelder) was retained by HDR Engineering, Inc. (HDR) to perform a geotechnical evaluation and pavement design for the proposed improvements related to the State

Highway (SH) 49 widening and resurfacing project, as part of the Federal Lands Access Program

(FLAP) at Medicine Park Trail in Comanche County, Oklahoma. The location of the project is shown on Figure 1, Site Location Diagram. The purpose of this report is to present the results of our fieldwork, laboratory testing, and our conclusions and recommendations related to pavement thickness design and pavement construction for the widening of the existing roadway. The information presented in this report will be used to support the preparation of construction plans, specifications, and engineering estimates for the Federal Highway Administration (FHWA), Central Federal Lands Highway Division (CFLHD) for the proposed roadway rehabilitation on SH

49. The project is described in Section B, Project Summary, of the Scope of Work (SOW) prepared by HDR for the Medicine Park Trail-SH49 Widening and Resurfacing, OK FLAP. The conclusions and recommendations provided in this report are subject to provisions outlined in

Section 9, Limitations.

The objective of our geotechnical explorations was to collect site-specific pavement and subgrade information, as well as subsurface information for the proposed widening. This information was used to characterize the pavement and subsurface conditions, provide engineering properties of the materials, and develop recommendations for pavement design, roadway widening, and construction associated with the proposed improvements of SH 49.

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1.2 SCOPE OF SERVICES

The scope of services performed for this project included the following:

• Conducting research related to the project scoping reports, historical roadway work, geotechnical/geological features, structures, as-builts, maintenance records, preliminary design criteria, project setting including regional and local geology, annual precipitation, frost depths, seismicity, soil conditions, surface and groundwater conditions, and any other related information;

• Development of a final geotechnical field investigation plan described in Step 3, Geotechnical Investigations of Section G (Geotechnical) and Section I (Pavement) of the

SOW;

• Performing subsurface field investigation preparation, coordination, and execution;

• Performing laboratory testing of soil samples;

• Developing Preliminary Recommendations;

• Preparation of this report summarizing our field investigation and pavement thickness design, and roadway widening recommendations.

1.3 PROJECT LOCATION AND DESCRIPTION

The proposed roadway improvement project is on SH 49, starting from Granite Ridge Drive in

Medicine Park, and extending east approximately 2.6 miles to SH 58 in Comanche County, Oklahoma. The roadway alignment is adjacent to the entrance of the Wichita Mountains Wildlife

Refuge. SH 49 provides access to private properties and the Wichita Mountains Wildlife Refuge.

The existing SH 49 alignment is an approximately 24 foot wide, two-lane, two-way roadway with grass covered shoulders. The existing alignment was built on a combination of at-grade, cut and fill sections. The existing SH 49 is classified as a highway, with a posted speed of 45 miles per hour. The roadway is maintained by the Oklahoma Department of Transportation (ODOT) District

7. The existing pavement is comprised of an asphaltic concrete surface with a thin layer of granular aggregate base. The existing pavement at the east end of the project limit is comprised of Portland cement concrete pavement.

After a site visit and completion of survey, the proposed modifications and improvements to SH

49 roadway included in this project are as follows:

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• Widening of the existing roadway;

• Mill and overlay of the existing asphaltic concrete pavement, except on the east end of the project limit as the existing Portland Cement concrete pavement will be replaced with new Asphaltic Concrete pavement;

• Construction of paved shoulders as the width of the shoulder is approximately 7-feet and will be comprised of asphaltic concrete pavement over aggregate base;

• Subgrade construction for the proposed widening;

• Ditch grading;

• Minor drainage structures and riprap placement;

• Signing, striping, and guardrails;

• Seeding and erosion control, and;

Based on discussions with CFLHD and HDR, and preliminary plans provided to us by HDR, it is our understanding that the following option is now being considered for the proposed roadway improvements:

• Mill the existing pavement sections by 2-inches, and overlay with new asphaltic concrete pavement. The overlay section will be designed by Kleinfelder based on the provided traffic counts, and the results of the field exploration and laboratory testing. The existing roadway will be widened by cutting into the existing slopes at the cut sections, and modifying the existing slopes with a steeper slope at the existing embankment sections. The original plan of using retaining walls for the widening in the cut and embankment sections were eliminated by allowing narrower shoulders, minimizing the cut into the existing slopes and drainage ditches, and modifications to the existing embankment.

The proposed improvements will be designed and constructed in accordance with the standards of ODOT, CFLHD, and FHWA.

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2 GEOLOGY

2.1 GEOLOGY

The project area is located in north central Comanche County of Southwestern Oklahoma.

According to the "Engineering Classification of Geologic Materials – Division Seven" from the

Oklahoma Department of Transportation, 1968, the majority of the alignment appears to be located within the Igneous Rock Unit (Cr) with a small portion appearing to be located within the

Post Oak Unit (Ppo) and Hennessey Unit (Phy).

Igneous Rocks Unit (Cr): This unit consists of granite and other rocks of similar material formed from a molten state. Other rocks within this group include gabbro, rhyolite, diorite, and anorthosite. The rocks are hard, massive, and sometimes resemble sedimentary rocks because of folding after solidification. The total thickness of the unit is undetermined but a drilled well within this unit has indicated that it is at least 4,500 feet thick.

The unit outcrops throughout northwestern Comanche County of Division 7. It is dissected by numerous faults. The Lower Arbuckle Unit normally overlies this unit but erosion has removed it from much of the area and subsequently the much younger Hennessey and Post Oak Units overlie the Igneous Rocks Unit throughout most of the Wichita Mountains.

Topographically, the unit forms the prominent mountains of the Wichita Mountains such as Mt.

Scott which stands some 1,100 feet above the surrounding area. The general topography varies from rugged barren rock exposures to rounded tree-covered hills. The more gently sloping areas are dominantly prairies.

Post Oak Unit (Ppo): This unit consists of detritus eroded from the Wichita Mountains and cemented to form conglomerates. The conglomerates may be divided into essentially two types:

(1) limestone conglomerate and (2) granite wash or conglomerate derived from igneous rocks.

The limestone conglomerate is prominent in southern Caddo County and along the northeastern limits of the Wichita Mountains in Comanche County. Here, the unit consists of limestone cobbles and pebbles derived from the adjacent limestones of the Upper and Lower Arbuckle Units of the

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Limestone Hills. The conglomerates are generally loosely cemented but locally tightly cemented and hard. The conglomerates are interbedded with red shale and local sandstones. The granite wash conglomerates grade southward from coarse boulders near the mountains into coarse cross-bedded arkosic sandstones which become interbedded with red shales. The total thickness of the unit ranges from 400 to 600 feet.

The Post Oak Unit outcrops in Comanche County and southwestern Caddo County of Division 7.

Here, it outcrops in various areas adjacent to the Wichita Mountains. Its outcrop is limited to an area within 6 to 10 miles of the mountains. The unit is gradational into the shales and sandstones of the Addington and Hennessey Units.

Topographically, the limestone conglomerate forms a gently sloping cobble-covered prairie bench that overlooks the lower valleys formed by the adjacent shales. The granite wash and interbedded shales form a gently sloping prairie covered slope which rises to the mountains.

Hennessey Unit (Phy): This unit consists dominantly of reddish-brown platy to blocky clay shales and mudstone with minor amounts of sandstone. Much of the shale is massive and breaks with sharp-edged conchoidal fractures. The red clay shale of the Hennessey Unit is characterized by numerous bands or streaks of white or light green color ranging from a few inches to four feet in thickness. Small spheres of light green color up to 10 inches in diameter are also an odd characteristic of the unit. Locally, in Stephens County, the shales are more gray than red. Soft buff massive sandstones are prominent near the base of the unit in Carter and Stephens Counties.

The total thickness of the unit thickens both westward and northeastward from a minimum of 130 feet in central Stephens County. It is 200 feet thick in the western part of Caddo County and about 400 feet thick in northeastern Stephens County.

In Division 7, the Hennessey Unit outcrops in an irregular 3 to 10 mile wide band around the nose of the Anadarko Basin; it then covers several square miles surrounding the Wichita Mountains in

Comanche and western Caddo Counties. Within ten miles of the Wichita Mountains, the strata of the Hennessey and Addington Units are gradational into the conglomerates of the Post Oak

Unit.

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Topographically, the unit is near level to gently rolling prairies but much of the more level outcrops of the unit are cultivated.

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3 GEOTECHNICAL EXPLORATIONS

3.1 GENERAL

During the scoping phase of the project, the field explorations included performing 7 pavement borings (P-1 to P-7), 4 cut section borings (B-1, B-3, B-4, and B-9) and 5 embankment/wall borings

(B-2, B-5, B-6, B-7 and B-8). The pavement borings were drilled to 5 feet below the existing ground surface. Cut section borings were drilled to depths ranging from 15 to 22 feet below exiting ground surface. Embankment borings were drilled to approximately 25 feet below existing ground surface or to top of bedrock, whichever occurred first. Cut section Boring B-3 was eliminated due to site access constraints.

3.2 FIELD EXPLORATIONS

3.2.1 Borings

The geotechnical exploration program was performed from June 17 to 19, 2015 and included advancing the following borings at the approximate locations indicated on the attached Figures 2 through 9, Boring Location Diagram(s). The approximate locations of the borings were estimated using a hand held GPS with an accuracy of 10 feet. A summary of the boring explorations is presented in Table 3-1.

TABLE 3-1. SUMMARY OF EXPLORATIONS1

Boring Approx.

Station

Approx.

Offset

(CL)

Boring Depth

(ft)

Existing

AC2

Thickness (inches)

Granular Base

Thickness (inches)

GWT Depth (ft)

Pavement Borings

P-1 109+21 10’ Rt. 5.0 6.0 3.0 NGWE1

P-2 128+74 7’ Lt. 5.0 6.0 3.0 NGWE1

P-3 146+92 7.5’ Rt. 4.03 6.0 3.0 NGWE1

P-4 166+00 7.5’ Lt. 5.0 7.0 3.0 NGWE1

P-5 189+17 11’ Rt. 5.0 6.5 1.5 NGWE1

P-6 212+75 7’ Lt. 5.0 5.5 4.5 NGWE1

P-7 236+78 7.5’ Rt. 5.0 8.0 2.0 NGWE1

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TABLE 3-1. SUMMARY OF EXPLORATIONS1

Boring Approx.

Station

Approx.

Offset

(CL)

Boring Depth

(ft)

Existing

AC2

Thickness (inches)

Granular Base

Thickness (inches)

GWT Depth (ft)

Cut Section Borings

B-1 130+78 60’ Lt. 17.5 N/A N/A NGWE1

B-4 167+85 48’ Rt. 18.0 N/A N/A NGWE1

B-9 196+27 60’ Lt. 16.0 N/A N/A NGWE1

Embankment Borings

B-2 136+04 7.5’ Lt. 14.0 6.0 3.0 NGWE1

B-5 171+35 7.5’ Rt. 23.5 6.0 2.5 NGWE1

B-6 172+85 7.5’ Rt. 23.5 6.0 3.0 NGWE1

B-7 180+05 7.0’ Rt. 18.5 8.0 2.0 NGWE1

B-8 181+05 7.5’ Rt. 14.0 7.0 3.0 13.5

1. NGWE = No groundwater was encountered in the boring, or dry prior to rock coring.

2. AC=Asphaltic Concrete

3. Auger refusal encountered at terminated depth

3.2.2 Sampling and Classification

A Kleinfelder geologist logged the borings by visually identifying and field classifying soils in general accordance with ASTM International Standard D2488 and the Unified Soil Classification

System (USCS). Upon completion of laboratory testing, soil classifications were further evaluated in general accordance with ASTM D2487 and are presented on the boring logs in Appendix B.

The exploratory borings were advanced with an ATV-mounted CME-550C drill rig using a combination of solid flight and rock coring techniques (cut section borings). Bulk and/or grab disturbed soil samples were obtained from pavement borings. Split-barrel sampling (ASTM

D1586) and thin-walled tube sampling methods (ASTM D1587) were conducted in the embankment/wall borings. The bedrock encountered in Borings B-1, B-4 and B-9 was cored using

NQ-diamond bit coring procedures. The samples were packaged and sealed in the field to reduce moisture loss and disturbance, and sent for laboratory testing. Upon completion of drilling, borings were backfilled with bentonite chips and patched at the surface with materials similar to the existing ground surface.

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The lines defining boundaries between material types on the logs are based on drill rig behavior and interpolation between samples, and are therefore approximate. Transition between material types may be abrupt or may be gradual.

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4 LABORATORY RESULTS

4.1 GEOTECHNICAL LABORATORY TESTING

Laboratory testing was conducted on materials collected from the subsurface borings during the field investigation. The intent was to run classification and strength tests on select representative materials obtained from the borings. The actual performed laboratory testing is modified from those described in the scoping reports in order to provide better subsurface information for the proposed improvements modified from the original scope in the SOW.

Table 4-1 summarizes the number and type of laboratory tests performed. Laboratory results are presented in Appendix C. Select lab results are also shown on the boring logs in Appendix B.

TABLE 4-1. SUMMARY OF GEOTECHNICAL LAB TESTING PROGRAM

TEST AASHTO/ASTM NO.

NUMBER OF

TESTS

Sieve Analysis (Coarse and Fines) AASHTO T 27/ASTM D 422 19

Atterberg Limits (plasticity index) AASHTO T 90/ASTM D 4318 19

Moisture Content AASHTO T 255 19

CBR1 AASTHO T 193/ASTM D 1883 3

Moisture-Density Relation With Standard Effort

AASHTO T 99 3

Unconfined Compression Test AASHTO T 206/ASTM D 2166 4

1 Based on sample molded to 95% of maximum dry density, and optimum moisture content as determined from AASHTO T 99

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5 SUBSURFACE CONDITIONS

The following description of the subsurface conditions encountered in the borings from our exploration program has been simplified for ease of report presentation. A more detailed description of the subsurface conditions encountered along the alignment is presented on the boring logs in Appendix B.

5.1 PAVEMENT BORINGS

Various thicknesses of pavement were encountered in the pavement borings. Asphaltic concrete pavement was encountered in all pavement borings with thicknesses ranging from about 5.5 to

8.0 inches. Aggregate base with thicknesses ranging from about 1.5 to 4.5 inches was encountered underneath the asphaltic concrete pavement. The approximate pavement thickness encountered at each pavement boring location (measured to the nearest 0.25-inch) is summarized in Table 3-1.

Fill materials comprised predominantly of sand with varying amounts of clay, silt, and gravel, and lean to fat clay with varying amounts of sand were encountered under the existing pavement section and continued to approximate depths ranging from approximately 1.3 to 4 feet below existing ground surface.

Weathered granite bedrock was encountered below the fill material in Borings P-1 through P-3 at approximate depths ranging from 2 to 2.5 feet below existing ground surface. Power auger refusal in granite bedrock was encountered in Boring P-3 at approximately 4 feet below ground surface.

Native soils comprised of sand with varying amounts of clay and gravel, and lean clay with varying amounts of silt and sand were encountered under the fill material and continued to the bottom of the exploration in Borings P-4 through P-7.

5.2 CUT SECTION BORINGS

Cut section borings B-1, B-4 and B-9 were drilled at the top of the existing cut slopes that were accessible to an all-terrain-vehicle (ATV) mounted drill rig. Approximately 1 to 2 inches of topsoil

20155113/ TUL15R24734-REV Page 12 of 32 August 14, 2014 was encountered in these borings. Overburden soils comprising gravel with varying amounts of sand and sand with varying amounts of silt were encountered under the topsoil and continued to approximately 3.5 feet below existing ground surface in Borings B-4 and B-9. Sandstone bedrock was encountered under the overburden soils and continued to the bottom of the exploration in

Borings B-4 and B-9. The upper 2 feet of the sandstone bedrock was generally weathered. The sandstone bedrock was generally poorly cemented and yellowish brown to brown in color. Granite was encountered under the topsoil and continued to the bottom of the exploration in Boring B-1.

The upper one foot of the granite was generally weathered. The granite was generally medium strong to strong and reddish brown, yellowish brown and gray in color.

5.3 EMBANKMENT BORINGS

The embankment borings were performed on the existing pavement. Asphaltic concrete pavement with thicknesses ranging from about 6 to 8 inches was encountered in the borings.

Aggregate base with thicknesses ranging from about 2 to 3 inches was encountered underneath the asphaltic concrete pavement.

Fill materials comprised of sand with varying amounts of clay, silt and gravel, gravel with varying amounts of clay and sand, and lean clay with varying amounts of sand were encountered under the pavement and continued to depths ranging from approximately 8 to 16.5 feet below existing ground surface.

Native soils comprised of clayey sand with gravel (in borings B5, B-6 and B-8) and sandy lean clay (in boring B-7) were encountered below the fill material and continued to approximate depths ranging from 13.5 to 18.8 feet below existing ground surface. The relative density of the clayey sand with gravel was generally medium dense and black, dark gray and yellowish brown in color.

The consistency of the native sandy lean clay encountered in Boring B-7 was generally firm and dark brown to dark gray in color.

Bedrock consisting of weathered granite, granite, and weathered sandstone was encountered underneath the overburden materials and continued to the bottom of the borings. The weathered granite and granite encountered in Borings B-2, B-5 and B-6 were generally weak to medium strong and reddish brown in color. The weathered sandstone encountered in Borings B-7 and B-

8 were generally poorly cemented with light gray and yellowish brown in color.

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5.4 GROUNDWATER

Groundwater was not encountered in the borings with the exception of Boring B-8 where groundwater was encountered at approximately 13.5 feet below existing ground surface during drilling operations. The borings were backfilled immediately following completion of drilling operations in order to open the road to traffic; thus, 24-hr groundwater readings were not obtained.

Additionally, drilling fluid was introduced in the borings where rock coring was performed.

Therefore groundwater levels in these borings were not measured at the end of the drilling.

The subsurface conditions encountered at this site are favorable for developing perched water table conditions on top of the weathered granite, granite and weathered sandstone bedrock.

Perched water table conditions can develop during wet seasons and should be considered for the design.

It should be noted that soil moisture levels and groundwater levels commonly vary over time depending upon seasonal precipitation, irrigation practices, land use and runoff conditions. The soil moisture and groundwater data in this report pertain only to the locations and times at which the explorations were performed. They can be extrapolated to other locations and times only with caution. It should be noted that Kleinfelder has not performed a hydrologic study to assess the seasonal groundwater conditions.

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6 PAVEMENT DESIGN, PAVEMENT MATERIALS, AND CONSTRUCTION

CONSIDERATIONS

6.1 PAVEMENT DESIGN

A pavement section is a layered system designed to distribute concentrated traffic Ioads to the subgrade. The performance of a pavement structure is directly related to the physical properties of the subgrade soils, pavement materials and thicknesses, surface drainage, and traffic loading.

For pavement design, parameters were chosen in general accordance with Chapter 11 of the

FHWA Project Development and Design Manual, 2008 Edition (PDDM). Kleinfelder performed the flexible pavement design using the AASHTOWare Program DARWin, which is based on the

1993 AASHTO Guide for Design of Pavement Structures (AASHTO 93).

Initial pavement improvement includes reclamation of the existing pavement to be used as subbase materials, and constructing a new pavement section for this project. However, based on the site visit, field exploration, and laboratory test results, the pavement improvement has been modified to mill and overlay of the existing pavement. Additionally, based on the thickness of the existing pavement sections, and the subgrade materials, the project alignment is divided into 2 sections. These 2 sections are:

Section 1: Western portion of project from Station 101+96.55 to Station 185+00

Section 2: Eastern portion of project from Station 185+00 to Station 242+86.72

6.1.1 Subgrade Materials and Strength

Based on the field exploration and laboratory test results, the strength of the subgrade soils were estimated based on the CBR test results and the results are summarized below:

Section 1: Representative Subgrade CBR of 12.5

Section 2: Representative Subgrade CBR of 4.3

These CBR values are based on the remolded subgrade samples prepared to approximately 95%

20155113/ TUL15R24734-REV Page 15 of 32 August 14, 2014 of the maximum dry density and at optimum moisture content, as determined from moisture-density relationship tests with standard effort (AASHTO T 99). It is estimated that the existing in-situ subgrade will have similar or better CBR values, based on the moisture contents of the subgrade soils, and SPT N values in the embankment borings.

These representative CBR values were used to calculate values for the subgrade resilient modulus. The subgrade soils resilient modulus (Mr) values within the project limits were estimated as 10,800 and 5,080 psi for Sections 1 and Section 2, respectively. The Mr values were estimated using the correlation between resilient modulus and other soil properties suggested by FHWA, and from Huang, 1993.

6.1.2 Pavement Distress Survey

A pavement distress survey was conducted by Kleinfelder on the existing asphalt pavement in general accordance with procedures outlined in ASTM D6433-11, which requires approximately 10 percent of the project length be surveyed. The pavement distress surveys were conducted at 7 sections along the SH 49 alignment within the project limits. Each pavement distress survey section covers an area of approximately 12 feet wide by 200 feet long. The pavement condition index (PCI) values were estimated based on the field observations. The pavement distress survey results are summarized in Table 6-1.

TABLE 6-1. PAVEMENT DISTRESS SURVEY RESULTS

Section No.

Direction

Approximate Pavement

Boring Location

Estimated Pavement Condition Index (PCI)

PCI Rating

1 Eastbound P-1 91 Good

2 Eastbound P-3 62 Fair

3 Eastbound P-5 77 Satisfactory

4 Eastbound P-7 63 Fair

5 Westbound P-2 92 Good

6 Westbound P-4 88 Good

7 Westbound P-6 56 Fair

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The primary pavement distresses identified within the project alignment were longitudinal and transverse cracking, edge cracking, and alligator cracking. These distresses were observed to have a severity of low to medium. Procedures outlined in Chapter 5 “Rehabilitation Methods with

Overlays” of the AASHTO Guide for Design of Pavement Structures (1993) should be followed for preparing and repairing existing pavements for overlaying.

6.1.3 Traffic Information

Based on traffic data provided by HDR, SH 49 has an average daily traffic (ADT) value of approximately 1,700, with the percentage of truck traffic ranging from 5% to 10%. The performance life of the pavement section is assumed to be 20 years. A truck percentage of 7% and annual growth percentage of 3% was selected for the pavement design for this project.

An average 20 year, 18-kip Equivalent Single Axle Load (ESAL) value of 944,866 was calculated using 18-kip ESAL factors from the FHWA PDDM and the AASHTO 93 pavement design method as presented in Appendix E.

6.1.4 Design Sections

Our designs are based on laboratory test results for the subgrade soils, the AASHTO 93 design criteria, and our experience. We calculated a 20-year design 18-kip ESAL of 944,866. If traffic studies indicate values that are significantly different, we should be contacted to review these recommendations. As requested by ODOT, the shoulder pavement section is assumed to have the same traffic data as the pavement sections. Tables 6-2 and 6-3 below present our design parameters and strength coefficients that are utilized in our pavement thickness calculations:

TABLE 6-2. SUMMARY OF PAVEMENT DESIGN PARAMETERS

Parameter Section 1

Value Section 2

Value Shoulder Value

Design Life 20 years 20 years 20 years

18-kip ESAL 944,866 944,866 944,866

Reliability 75% 75% 75%

Overall Standard Deviation 0.49 0.49 0.49

Initial Serviceability Index 4.2 4.2 4.2

Terminal Serviceability Index 2.5 2.5 2.5

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TABLE 6-3. SUMMARY OF STRENGTH COEFFICIENTS

Parameter Section 1

Value Section 2

Value Section 1 Shoulder

Section 2 Shoulder

ACP Structural Coefficient 0.44 0.44 0.44 0.44

Existing Pavement Structure Coefficient 0.25 0.25 N/A N/A

ACP Drainage Coefficient 1.0 1.0 1.0 1.0

Aggregate Base Structural Coefficient 0.12 0.12 0.14 0.14

Aggregate Base Drainage Coefficient 1.0 1.0 1.0 1.0

Roadbed Soil Resilient Modulus 10,800 psi 5,080 psi 10,080 psi 5,080 psi

Structural coefficients for the Asphalt Concrete Pavement (ACP) and Aggregate Base were chosen in accordance with Exhibit 11.2-C in Section 11.2.1.4 of the 2008 FHWA PDDM, corresponding with values for Bid Item 401 ACP (Superpave mix) and Bid Item 301 Crushed

Aggregate Base.

Based on the chosen design parameters and strength coefficients, the composite sections presented in Table 6-4 are recommended. These sections will meet the typical 20-year pavement design life.

TABLE 6-4. SUMMARY OF RECOMMENDED PAVEMENT SECTIONS

Section Mill and Overlay

(Sta. 101+96.55 to Sta. 185+00)

Mill 2” of Existing Asphaltic Concrete Pavement Overlay with 4” ACP

(Sta. 185+00 to Sta. 242+86.72)

Mill 2” of Existing Asphaltic Concrete Pavement Overlay with 5.5” ACP

Section

Hot Asphalt Concrete Pavement (ACP) overlying

Crushed Aggregate Base Course (ABC);

(New Pavement Section)

Shoulder 1 (Sta. 101+96.55 to Sta. 185+00)

4” ACP

9” ABC

Shoulder 2 (Sta. 185+00 to Sta. 242+86.72)

5.5” ACP

9” ABC

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6.2 PAVEMENT MATERIALS

6.2.1 Asphalt Mix

A ACP Superpave design mix, or a State Department of Transportation asphalt concrete pavement mixture as specified in Section 403 of the FP-14 (FP-14), Standard Specifications for

Construction of Roads and Bridges on Federal Highway Projects, is recommended. A commercially produced, heat stable liquid anti-strip additive should be added to the asphalt mix to prevent separation of the asphalt from the aggregates. Based on the ODOT “Suggested

Guidelines for Asphalt Pavements”, PG 64-22 is recommended to be used as asphalt binder for the shoulder, and overlay section that is deeper than 4-inches below the final grade. Asphalt binder PG 70-28 is recommended to be used within the top 4-inches of the pavement.

6.2.2 Crushed Aggregate Base Course

Untreated aggregate base course in accordance with Section 301 of the FP-14, is recommended with a maximum size of 1-inch. Crushed aggregate base course should be uniformly graded, and free of organic matter, lumps or balls of clay, and other deleterious materials. The maximum dry density of the ABC should be determined according to AASHTO T 180, method D. ABC should be compacted to at least 95 percent of maximum density and within 2 percent of the optimum moisture content, and should be spread in layers not exceeding 6-inches in compacted thickness.

The new ABC should have a Hveem R-Value of at least 80.

6.2.3 Milling, Crack Sealing and Overlay

Mill and overlay is anticipated on the existing pavement. Milling of the existing pavement should be performed in accordance with Section 413 of FP-14, Asphalt Pavement Milling. After milling, repairing of deteriorated areas to include crack sealing should be performed prior to overlay. The crack sealing should be performed in accordance with Section 414 of FP-14, Asphalt Pavement

Crack and Joint Sealing. Construction of an Asphaltic Concrete (AC) overlay of the existing pavement consists of the following tasks:

1. Repairing deteriorated areas including crack sealing;

2. Correcting surface rutting by milling or placing a leveling course;

3. Constructing widening;

4. Applying a tack coat; and

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5. Placing Asphaltic Concrete overlay.

Guidelines outlined in Chapter 5 “Rehabilitation Methods with Overlays” of the AASHTO Guide for Design of Pavement Structures (1993), ODOT “Standard Specifications for Highway

Construction (2009), and FP-14 should be followed for mill and overlay.

6.2.4 Tack and Prime Coat

Prime coat should also be applied to prepare the ABC at a rate as specified in Section 411 of FP-

14. Application should take place when it is not foggy or rainy and when air temperature in the shade is above 50 degrees F and rising. Allow tacked surfaces to cure for at least 24 hours before placing the covering course.

Per Section 412 of the FHWA FP-14, a tack coat should be applied if the HACP is applied in more than one lift, at a rate of 0.03 to 0.15 gal/yd2 between each lift of HACP. Prior to application, prepare the existing surface by removing deleterious substances and ensure that the surface is dry and unfrozen, and that the air temperature in the shade is above 35 degrees F and rising.

Allow tacked surfaces to cure and place the covering course within 4 hours of placing tack coat.

Emulsified asphalt specified in subsection 702.02 of FP-14 should be used.

6.3 CONSTRUCTION CONSIDERATIONS

Unless other Federal or local agency requirements or specifications apply or are specifically incorporated into the project, roadway construction should be performed per the FHWA Standard

Specifications for Construction of Roads and Bridges on Federal Highway Projects (FP-14). The following sections provide recommendations associated with design and performance of the proposed pavement section as provided herein.

6.3.1 Subgrade Preparation

Any obviously unsuitable materials present (e.g. debris, organic materials, waste) larger than 6-inches should be completely removed from the top 6-inches of subgrade. Remove the stripped materials for offsite disposal in accordance with Section 204.14 of FP-14.

Prior to placement of new embankment fill or pavement sections, processing of the subgrade should be performed per Section 303 of FP-14. Per subsection 204.10 of FP-14, the subgrade

20155113/ TUL15R24734-REV Page 20 of 32 August 14, 2014 should be scarified to a minimum depth of 6-inches, and surface irregularities removed. The subgrade surface should be moisture conditioned to the moisture content shown in Table 7-6, and compacted to a minimum 95% (AASHTO T 180 or T 99, see Section 204.11 of FP-14) of the laboratory maximum dry density for pavement subgrade and existing base course.

The construction of the shoulder subgrade will encounter clay soils (in-place or imported) in portions of the project limits. If the construction is performed during wet seasons, soft and unstable subgrade soils should be anticipated. Undercutting the soft surficial soils, replacement with structural fill materials or scarifying, moisture conditioning and compacting of the subgrade soils should be anticipated. Alternatively, soil stabilization with lime or cement can also be performed. The modifications to the subgrade soils can impact the budget of the project significantly and should be taken into consideration.

Prior to placing the pavement section including aggregate base course, the pavement subgrade should be proof-rolled with compression-type rollers at speeds less than 6 feet per second and vibratory rollers at speeds less than 3 feet per second. Areas that pump or deform significantly under heavy wheel loads are not stable and should be removed and replaced to achieve a stable subgrade prior to paving. Care should be taken to ensure areas around manholes or other utility protrusions are proof-rolled adequately.

Any soft and/or wet areas exposed during the excavation process may need to be stabilized prior to placement of new fill and pavement sections to create a stable and firm construction platform per Section 204.07 of FP-14. The method and extent of stabilization will depend on the actual conditions encountered, and the more appropriate method of stabilization will likely be best determined in the field at the time of excavation, by Kleinfelder representatives. Typical stabilization methods may include rock stabilization utilizing geo-grid such as Tensar TX140 or

TX160, and Aggregate Base Course (or similar) to form a stable base on which to place the pavement section. Installation typically includes placement of the geo-grid directly on subgrade with on the order of 12 to 18-inches of ABC above the grid. Rock aggregate size and depth of mitigation will vary depending on actual conditions encountered and would require adjustment during construction.

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6.3.2 Drainage

Proper drainage is of paramount importance in enhancing pavement performance. To avoid distress to pavement from wet, soft subgrade soils, we recommend the maintenance of good drainage away from all pavements. Possible water sources include storm runoff, irrigation of landscaping adjacent the pavement and localized groundwater seepage, among others. Joints in the pavement or at asphalt/concrete interfaces should be sealed. Any cracks or openings in the finished pavement surface should be sealed and/or repaired as quickly as possible.

6.3.3 Pavement Maintenance

Annual maintenance generally refers to crack filling and general surface sealers. We recommend implementation of an at least annual if not more frequent pavement crack sealing program. This is very important to prevent surface water from entering cracks and wetting the subgrade. Due to temperature fluctuations significant separations can also occur at interfaces between the asphalt pavement concrete elements, and other features. These areas generally result in a high rate of premature distress and failure that can propagate well beyond the original problem area.

Any cracks or openings in the finished pavement surface should be sealed and/or repaired as quickly as possible.

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7 ROADWAY WIDENING

7.1 GENERAL

Initially, it was intended to utilize retaining wall structures for the roadway widening. After the site visits, and discussions with CFLHD and ODOT, it was decided to widen the roadway with narrower shoulders and modifications to the drainage ditches to minimize the widening of the roadway. As the result, it is proposed to construct the roadway widening in the embankment areas by using steeper slopes and “sliver” fills. Minor excavation into the existing cut slope is also anticipated in one area for the widening. To evaluate the stability of the proposed steeper embankment slopes for the roadway widening, we performed slope stability analyses for two different potential failure modes: 1) end of construction of the embankment (short term/undrained case) and 2) long term

(drained case). The slope stability analyses were performed using the computer program

"Slope/W" which calculates the factor of safety (FOS) of a slope using the Spencer limit equilibrium method of slices. The analyses were performed using the provided cross-sections at

Stations 136+50, 171+00 and 180+50. The FOS, by definition, is equal to the ratio of resisting forces to driving forces. The minimum required slope stability FOS against failure for the purpose of this project has been taken as 1.3 for the undrained case and 1.5 for the drained case.

Additionally, we estimated the rippability of the bedrock encountered based on the rock cores, and unconfined compression test results of the cores. The slope stability of the rock cut sections is beyond the scope of the work for this project.

7.2 SLOPE STABILITY SHEAR STRENGTH PARAMETERS

Shear strength parameters for the existing embankments were estimated based on our experience with native soils in the area, field explorations, and laboratory testing results. Slope stability analyses were performed assuming that “sliver” fills will be constructed with either cohesive soils (clay) or the cohesionless soils (sand). The estimated shear strength parameters used in the analyses are presented in Table 7-1, 7-2 and 7-3 for Station 136+50, 171+00 and

180+50, respectively, and again in the graphical Slope/W output files presented in Figures D-1 through D-11, in APPENDIX D of this report.

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TABLE 7-1. SHEAR STRENGTH PARAMETERS AT STATION 136+50

Material

Unit

Weight

, pcf

Undrained

(Short Term)

Drained

(Long Term)

Friction angle, degrees

Cohesion, psf

Friction angle, degrees

Cohesion, psf

Cohesionless Sliver Fill 125 36 0 36 0

Cohesive Sliver Fill 125 0 1,000 26 100

Existing Sandy Embankment 125 34 50 34 50

Existing Clayey Gravel Fill

(Broken Granite) 125 36 0 36 50

Granite Bedrock (Impenetrable)

TABLE 7-2. SHEAR STRENGTH PARAMETERS AT STATION 171+00

Unit

Weight

, pcf

Undrained

(Short Term)

Drained

(Long Term)

Friction angle, degrees

Cohesion, psf

Friction angle, degrees

Cohesion, psf

Cohesionless Sliver Fill 125 36 0 36 0

Cohesive Sliver Fill 125 0 1,000 26 100

Existing Sandy Embankment 125 34 50 34 50

Native Clayey Sand w/

Gravel 125 34 0 34 0

Granite Bedrock (Impenetrable)

TABLE 7-3. SHEAR STRENGTH PARAMETERS AT STATION 180+50

Unit

Weight, pcf

Undrained

(Short Term)

Drained

(Long Term)

Friction angle, degrees

Cohesion, psf

Friction angle, degrees

Cohesion, psf

Cohesionless Sliver Fill 125 36 0 36 0

Cohesive Sliver Fill 125 0 1,000 26 100

Existing Sandy Embankment 125 32 50 32 50

Native Sand Soil (SM) 125 32 0 32 0

Sandstone Bedrock (Impenetrable)

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7.3 SUMMARY OF SLOPE STABILITY RESULTS

The factors of safety computed for the section analyzed are summarized in Table 7-4, and graphical Slope/W output files are provided in Figures D-1 through D-11 in APPENDIX D. As indicated by the stability analyses results, the proposed cross-sections and slopes generally exhibit an acceptable calculated FOS against overall slope failure in the short-term and long-term

(≥1.3 or 1.5, respectively). If instability of the embankment slope is observed during construction, all fill placement activities should cease immediately and the geotechnical engineer should be contacted.

The slope stability analyses were performed based on the estimated shear strength properties of the “sliver” fill materials. The shear strength parameters of the soils used for sliver fill should be evaluated once the potential borrow material source has been selected. Additional slope stability analyses may be required to assess the influence of the shear strength parameters of the selected fill material(s).

TABLE 7-4. SLOPE STABILITY ANALYSIS RESULTS

Station

Granular Embankment Fill Cohesive Embankment Fill

Short Term (Undrained)

Long Term (Drained)

Short Term (Undrained)

Long Term (Drained)

136+50 1.37 1.59 1.56 1.61

171+00 1.73 1.72 1.78 1.74

180+50 1.68 1.68 1.83 1.69

For embankments constructed from cohesionless soils (sand, gravel or combinations thereof) slope stability was analyzed using a minimum slip surface depth of 5 feet. The use of this constraint ignores failure surfaces shallower than 5 feet in depth, as shallow surface or “skin” slides are generally considered a maintenance issue and should be addressed through operations and maintenance (O&M) procedures, such as observation of the slope on a periodic basis and after prolonged precipitation events.

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Embankments constructed with cohesionless materials are subject to erosion and scour due to water flow over the embankment face. Although erosion analysis is beyond the scope of our analysis, it is generally recommended that embankment slopes be armored and/or well vegetated

(with appropriate grass cover) to assist in reducing the influence of water that may flow over the face of the embankment, regardless of embankment material type. Water should be channeled away from the slope face to reduce the possibility of erosion due to water flow.

Where the new sliver embankment ties into the existing embankments, we recommend that new fill be benched laterally into the existing slopes at least 5 feet to allow compaction of any loose zones. This bench must be done in a manner that will not reduce the stability of the existing slopes. It is recommended benches have a maximum height of 3 feet. The existing slopes should be monitored each day both visually and with elevation points to detect zones of instability. If fill placement during construction of the embankments is not continuous, the surface of each lift should be scarified and moisture conditioned prior to placement of the next lift.

7.4 CONSTRUCTION CONSIDERATIONS

7.4.1 Excavation Characteristics

Excavation into the overburden soil material can likely be accomplished utilizing conventional standard duty earth moving equipment. A seismic refraction survey to determine the rippability of the bedrock was beyond the scope of this study. Rippability of the bedrock was estimated based on the results of point load tests (correlated to unconfined compression tests), and the fracture/discontinuity spacing of the bedrock cores based on the “Excavatability Assessment

Chart” published by “Pettifer and Fookes, 1994”. The granite and sandstone bedrock is rated as easy to hard ripping materials. However, pneumatic hammer is anticipated to be required during construction. Pictures of the rock cores obtained during this investigation are presented in Appendix F.

Groundwater was not encountered in our borings during this investigation, except in Boring B-8 where groundwater was encountered at a depth of approximately 13.5 feet below the ground surface at the end of drilling operations. However, based on our experience in the area and shallow bedrock in the borings, localized areas of shallow groundwater, perched water table or surface drainage can develop in the vicinity and localized groundwater seepage can be

20155113/ TUL15R24734-REV Page 26 of 32 August 14, 2014 encountered at random locations and elevations within the soils and is subject to seasonal precipitation events. Therefore, where operations encounter shallow groundwater or surface water construction dewatering may be required. Utilizing appropriate construction dewatering equipment/systems, such as well points, sumps, and trenches, will be the responsibility of the contractor. A dewatering expert should be retained as appropriate. In addition, trenching into wet and/or saturated overburden soils will require temporary shoring, where the construction of safe unshored slopes is not feasible.

All excavations must comply with the Section 204 of FP-14, ODOT “Standard Specifications for

Highway Construction (2009)” Section 202, and any applicable local, State and Federal safety regulations, and particularly with the excavation standards of the Occupational Safety and Health

Administration (OSHA). Construction site safety, including excavation safety, is the sole responsibility of the Contractor as part of its overall responsibility for the means, methods and sequencing of construction operations. Kleinfelder’s recommendations for excavation support are intended for the Client’s use in planning the project, and in no way relieve the Contractor of its responsibility to construct, support and maintain safe slopes. Under no circumstances should the following recommendations be interpreted to mean that Kleinfelder is assuming responsibility for either construction site safety or the Contractor’s activities.

We believe that the near-surface soils on this site will classify as Type C materials using OSHA criteria. OSHA requires that unsupported cuts be laid back to ratios no steeper than 1.5H:1V

(horizontal to vertical) up to 20-feet in height. In general, we believe that these slope inclinations will be temporarily stable under unsaturated conditions. Where groundwater seepage/saturated conditions occur, flatter slopes will be appropriate. Please note that the actual determination of soil type and allowable sloping must be made in the field by an OSHA-qualified “competent person.”

7.4.2 Structural Fill

Structural fill refers to material that is appropriate for placement beneath structure components, embankment fill, and pavement subgrade. If imported fill is required to meet proposed site grades, it should consist of a non-expansive, sandy lean clay or clayey sand material meeting the requirements presented in Table 7-5. This table is modified based on the Table 704-1, Section

704.07 of FP-14. The modifications for the structural fill materials is intending to provide more stable sliver fill slopes.

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A sample of any proposed imported structural fill should be submitted to our office for review and testing at least 3 days prior to stockpiling at the site. The native subgrade to receive structural fill should be prepared in accordance with Section 6.3.1.

TABLE 7-5. IMPORTED STRUCTURAL FILL CRITERIA

Gradation Requirements

Standard Sieve Size Percent Passing

3 inch 100

1 inch 70-100

No. 4 30-70

No. 200 30-65

Plasticity Requirements (Atterberg Limits)

Liquid Limit 30 or less

Plasticity Index 5 to 15

A representative of Kleinfelder should perform testing and observation of the subgrade structural fill placement.

7.4.3 Compaction Requirements

Soil and aggregate materials should be placed on a horizontal plane and placed in loose lifts not to exceed 6-inches in compacted thickness, unless otherwise accepted by the geotechnical engineer. Materials should be moisture-conditioned and compacted according to following criteria specified in Table 7-6.

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