Geotechnical_Report.pdf

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DRAFT REPORT

STRUCTURE FOUNDATION EXPLORATION

SHEPHERD STREET BRIDGE REPLACEMENT

(OVER LOONEY CREEK)

HARLAN COUNTY, KENTUCKY

Prepared For:

WOOLPERT

One Easton Oval, Suite 310

Columbus, Ohio 43219

Prepared by:

NATIONAL ENGINEERING AND ARCHITECTURAL SERVICES INC.

2800 Corporate Exchange Drive, Suite 240

Columbus, Ohio 43231

NEAS PROJECT 16-0156

MARCH 29, 2017

- 1 - NEAS Project 16-0156 March 29, 2017

EXECUTIVE SUMMARY

The Nashville District of the United States Army Corps of Engineers (USACE) has proposed a bridge replacement project for the existing bridge located along Shepherd Street within the City of Cumberland, Harlan County, Kentucky. The referenced project is part of the City of Cumberland, Kentucky Flood Damage Reduction Project as authorized by Section 202 of the Energy and Water Development Act of 1981 (PL96-367). The overall project is part of a phased channel widening flood reduction project for Looney Creek and the subject project objectives are to replace the existing Shepherd Street Bridge including associated modifications and relocations of the approach roadways in a way that incorporates the overall flood reduction project.

National Engineering & Architectural Services, Inc. (NEAS) has been contracted to perform geotechnical engineering services for the bridge replacement project. The purpose of the geotechnical engineering services was to perform geotechnical explorations within the project limits to obtain information concerning the subsurface soil and groundwater conditions relevant to the design and construction of the project. Between December 9, 2016 and December 14, 2016, NEAS performed the site reconnaissance and exploration program for the project. The subsequent document presents the results of the structure foundation exploration with respect to the proposed Shepherd Street Bridge replacement. As part of the project, NEAS advanced 2 project borings, performed 1 geotechnical rockline sounding, and conducted laboratory testing to characterize the soils for engineering purposes. The existing Shepherd Street Bridge is a single span concrete cast-in-place slab bridge carrying Shepherd Street over Looney Creek that was originally built in the 1950s with an asphalt pavement surface.

The subsurface profile at the bridge replacement site is generally consistent with the geological model for the project in regards to the materials encountered. The subsurface profile within the proposed project area consists of surficial materials comprised of an existing pavement section, underlain by 4 to 7 ft of possible fill soils comprised of silt and sand mixtures over natural alluvial soils to depths ranging from 14 to 21 ft below ground surface (bgs) (approximate elevations 1429.5 ft and 1422.5 ft above mean sea level (amsl)). Bedrock consisting of shale and shale interbedded with siltstone was encountered immediately below the natural soils within each of the borings and geotechnical rockline sounding performed. The possible fill soils generally consisted of various mixtures of sand, silt and gravel with either a consistency of very stiff to hard (cohesive mixtures) or a relative density of medium dense to dense (non-cohesive mixtures). The natural alluvial soils generally encountered at depths ranging from depths of 4 to 7 ft bgs and extending to bedrock were comprised of medium dense to very dense silty sands.

Bridge analyses of deep foundation systems were performed for the two substructure locations of the bridge based on developed soil profiles at the referenced boring locations. For the analyses, HP12X53 steel "H" piles were considered and the maximum total factored loads on a single pile provided by Woolpert (project structural engineer) were assumed. Based on our analyses, it is recommended that the piles be placed within pre-bored holes, embedded at least 3 ft into bedrock and encased in grout. Piles installed in accordance with the recommendations provided within this report, will be point bearing piles seated in shale bedrock or in the weathered shale directly above the shale bedrock at elevations ranging from 1420 to 1426 ft amsl. At the indicated pile tip elevations it is anticipated that the piles will bear on sound bedrock that will provide sufficient resistance for the design loads and provide the minimum pile embedment depth of at least 10 ft below the bottom of pile cap elevation. With respect to global stability and settlement at the proposed bridge replacement location, as approach embankments have been fully formed since the original construction of the bridge and there are no planned significant changes to their configuration, the existing slopes are expected to remain stable and settlement will be minimal. It should be noted that an evaluation of pile drivability is not applicable to the recommended pile installation method (pre-bored hole) and therefore is not presented within this report.

Structure Foundation Exploration - DRAFT Shepherd Street Bridge Replacement City of Cumberland, Kentucky

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TABLE OF CONTENTS

1. INTRODUCTION

1.1. GENERAL

1.2. PROPOSED CONSTRUCTION

2. GEOLOGY AND OBSERVATIONS OF THE PROJECT

2.1. GEOLOGY AND PHYSIOGRAPHY

2.2. HYDROLOGY/HYDROGEOLOGY

2.3. HISTORICAL RECORDS

2.4. SITE RECONNAISSANCE

3. GEOTECHNICAL EXPLORATION

3.1. FIELD EXPLORATION PROGRAM

3.2. LABORATORY TESTING PROGRAM

3.2.1. Classification Testing

3.2.2. Standard Penetration Test Results

3.2.3. Streambed Grain Size Distribution

3.2.4. Unconfined Compressive Strength Of Rock Cores

3.2.5. Slake Durability Test Results

4. GEOTECHNICAL FINDINGS

4.1. SUBSURFACE CONDITIONS

4.1.1. Overburden Soil

4.1.2. Groundwater

4.1.3. Bedrock

5. ANALYSES AND RECOMMENDATIONS

5.1. SOIL PROFILE FOR ANALYSIS

5.2. BRIDGE FOUNDATION ANALYSIS

5.2.1. Deep Foundation Analysis

5.2.1. Pile Drivability ...................................................................... Error! Bookmark not defined.

5.3. FOUNDATION RECOMMENDATIONS

6. QUALIFICATIONS

LIST OF TABLES

TABLE 1: PROJECT BORING SUMMARY

TABLE 2: STREAMBED GRAIN SIZE ANALYSIS RESULTS

TABLE 3: UNCONFINED COMPRESSIVE STRENGTH OF A ROCK CORE TEST RESULTS

TABLE 4: SLAKE DURABILITY TEST RESULTS

TABLE 5: BEDROCK SUMMARY

TABLE 6: REAR ABUTMENT - SOIL PROFILE AND ESTIMATED ENGINEERING PROPERTIES (B-001-0-16) TABLE 7: FORWARD ABUTMENT - SOIL PROFILE AND ESTIMATED ENGINEERING PROPERTIES (B-002-0-16 &

S-001-0-16)

TABLE 8: ESTIMATED PILE LENGTHS SUMMARY

LIST OF APPENDICES

APPENDIX A: STRUCTURE FOUNDATION EXPLORATION SHEETS

APPENDIX B: SOIL BORING LOGS & LABORATORY TEST RESULTS

APPENDIX C: DRIVEN ANALYSIS

APPENDIX D: DRIVABILITY ANALYSIS

City of Cumberland, Kentucky

- 3 - NEAS Project 16-0156

1. INTRODUCTION

1.1. General

NEAS presents our Structure Foundation Exploration Report for the proposed Shepherd Street Bridge replacement project. The referenced bridge is located in Harlan County, Kentucky within the limits of the City of Cumberland and carries Shepherd Street over Looney Creek. In addition to replacement of the bridge, the referenced project will include associated modifications and relocations of the approach roadways. The planned project is to be performed as part of and in conjunction with the City of Cumberland, Kentucky Flood Damage Reduction Project and associated phased channel widening of Looney Creek. This report presents a summary of the encountered surficial and subsurface conditions and our recommendations for bridge foundation design and construction in accordance with the Load and Resistance Factor Design (LRFD) method as set forth in AASHTO's Publication LRFD Bridge Design Specifications, 7th Edition with 2015 interim revisions (BDS) (AASHTO, 2014), Kentucky Transportation Cabinet's (KYTC's) 2005 Structural Design Guidance Manual (KYTC [1], 2005) with 2008 revisions within KYTC's Transmittal Memo 08-01, and KYTC's Geotechnical Guidance Manual

(GGM) (KYTC [2], 2005).

The exploration was conducted in general accordance with Barr Engineering, Inc. DBA National Engineering and Architectural Services Inc's (NEAS's) proposal to Woolpert dated August 29, 2016 and with the provisions of KYTC's GGM (KYTC [2], 2005).

The scope of work performed by NEAS as part of the referenced project included: a review of published geotechnical information; performing 2 test borings and 1 geotechnical rockline sounding; laboratory testing of soil samples in accordance with the GGM; performing geotechnical engineering analysis to assess foundation design and construction considerations; and development of this summary report.

1.2. Proposed Construction

The existing Shepherd Street Bridge consists of a single span concrete cast-in-place slab, built in the 1950s with an asphalt pavement surface. The existing structure has a span of about 39 ft (back of abutment to back of abutment) with a width of about 26 ft (edge to edge) and a clear roadway width of 18 ft. The structure carries two lanes of traffic on the concrete slab which is supported by wall type abutments and either a shallow spread foundation or deep pile foundation.

Based on the Cumberland, Kentucky - Shepherd Street Bridge Replacement over Looney Creek - 60% Site Plans dated January 27, 2017 provided by Woolpert on January 30, 2017, the existing structure will likely be replaced with a pre-cast composite box beam superstructure on semi-integral abutments. The replacement structure is proposed to have a span of about 70 ft, a total width of about 30 ft and a clear roadway with of 22 ft. The proposed bridge will be supported by the natural soil/rock through the use of a deep foundation system.

2. GEOLOGY AND OBSERVATIONS OF THE PROJECT

2.1. Geology and Physiography

The site of the Shepherd Street bridge over Looney Creek is relatively flat in the immediate vicinity of the bridge site. The City of Cumberland is located within a valley region and the bridge site is located within the northeastern portion, near the approximate valley edge with topography sloping upward to east and to the north within approximately 400 ft of the site.

City of Cumberland, Kentucky

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The project site is located within the Cumberland Escarpment physiographic region that is located within the eastern edge of the Eastern Kentucky Coal Field region (KGS, 2015). This region forms the western edge of the Cumberland Plateau and consists of a resistant sandstone belt of cliffs and steep sided, narrow crested valleys in eastern Kentucky. The geology can be described as resistant Pennsylvanian-age sandstones, conglomerates, shales, and siltstones.

The Quaternary geology of the bridge site is mapped as alluvium and consists of a combination of sand, gravel, silt and clay. As much as 5 feet of bedded sand, silt, and clay with scattered pebbles overlies channel gravel in terrace deposits where flood plains are broad. Channel gravel is composed of flat, rounded cobbles and boulders of sandstone and siltstone from nearby outcrops. (KGS, 2016). Alluvium occurs mainly in poorly stratified, unconsolidated deposits on valley bottoms. The bedrock beneath the bridge site has been mapped as interbedded Pennsylvanian-age shale, siltstone, sandstone, coal, and conglomerate with siltstone as the major lithological constituent and is within the lower part of the Breathitt Formation (USGS & KGS, 1988). The bedrock is anticipated to be encountered at similar elevations to the Blair Street bridge, expected at elevations between 1420 and 1425 ft amsl. This places bedrock at a depth between 15 and 25 ft bgs at the bridge site.

The soils at the bridge site have been mapped (Web Soil Survey) by the Natural Resources Conservation Service as Udorthents-Urban Land Complex (USDA, 2015). Udorthents are identified as soils that have been disturbed by cutting or filling and not rated for local roads.

2.2. Hydrology/Hydrogeology

Groundwater can be expected at an elevation consistent with that of the immediately adjacent Looney Creek and the Poor Fork Cumberland River, as they are the most dominant hydraulic influences in the immediate vicinity with the topography in the immediate area sloping towards the Poor Fork Cumberland River. Based on available topographic information, the streambed elevation of Looney Creek at this location is estimated at approximately 1433 to 1435 ft amsl. This elevation may be generally representative of the local groundwater table.

The bridge site is located within a regulatory floodway as well as within a 1% Annual Chance Flood Hazard area based on available mapping by the Federal Emergency Management Agency's (FEMA) National Flood Hazard mapping program (FEMA, 2016).

2.3. Historical Records

A historic record search was performed; however, no historic boring information was available for review within the limits of the bridge replacement project.

2.4. Site Reconnaissance

A field reconnaissance visit for the project site was conducted on December 9, 2016 along Shepherd Street at the proposed bridge replacement site.

During our field reconnaissance, no geohazards were observed within the immediate vicinity of the project. Existing stream bank slopes at the bridge abutment locations were observed to be relatively steep with reinforced concrete wing walls extending to either side of both abutments. The wing walls appeared to be in good condition with no observable signs of distress. The stream bank on either side of Looney Creek appeared to consist of large pieces of buried debris (i.e., concrete rubble, stone, etc.) mixed with soil (See Photograph 1). Vegetation consisting of heavy vines, shrubs, trees and other vegetation generally covered the stream bank material. Furthermore, it appeared that berms had been constructed at roadway grade on either side of the creek along the stream bank.

City of Cumberland, Kentucky

- 5 - NEAS Project 16-0156

The bridge site appeared to be well drained with no observable signs of standing water on the roadway.

The water level in the stream was relatively low at the time of the reconnaissance with stream depths up to about 18 inches at the base of the southern abutment and exposed stream bed along the northern abutment. It should be noted that possible signs of erosion or scour were observed along the base of the southern abutment.

The overall condition of the structure appeared to be in good condition with very little signs of distress (See Photograph 2). Some minor deterioration of the concrete deck was observed on the east side of the existing deck as well as some minor cracking on the southern abutment. The pavement condition along the bridge appeared to be in good condition with very little signs of notable distress. Furthermore, no geotechnical related distress was apparent at the bridge site during our reconnaissance.

Photograph 1: Existing stream bank and southern abutment

Photograph 2: Overall bridge looking north

City of Cumberland, Kentucky

- 6 - NEAS Project 16-0156

3. GEOTECHNICAL EXPLORATION

3.1. Field Exploration Program

The exploration for this bridge was conducted by NEAS on December 13 and 14, 2016 and included two

(2) borings (B-001-0-16 and B-002-0-16) drilled to depths of between 24.5 and 27.0 ft bgs, and one

(1) geotechnical rockline sounding (S-001-0-16) drilled to a depth of 21.3 ft bgs. The boring and sounding locations were selected by NEAS in general accordance with the guidelines contained in KYTC's GGM with the intent to evaluate subsurface soil and groundwater conditions. Exploration locations were typically located at/near proposed substructure locations that were not restricted by maintenance of traffic, underground utilities or dictated by terrain (i.e., steep embankment slopes). Each exploration location was established in the field by measuring from the existing structure (two perpendicular distances) utilizing a cloth measuring tape. Ground surface elevations and coordinate location information for each established exploration location were interpolated from the topographic survey data included in USACE’s Topographic Survey of Shepherd Street, Cumberland, KY (Drawing 1 of 1), dated October 14, 2016. Each individual project boring and sounding log (included within Appendix B) includes the determined boring coordinate location (based on the surveyed Kentucky South, NAD83, location) and the corresponding ground surface elevation. Stationing, offsets and elevations of the explorations are shown on Table 2 and the locations are depicted on the Boring Location Plan provided in Appendix A.

Table 1: Project Boring Summary

Borings were drilled using a CME 55 truck mounted drilling rig utilizing 3.25-inch diameter hollow stem augers and NQ2 coring equipment. Soil samples were generally recovered at 2.5-ft intervals to a depth of 10 ft bgs and at 5.0-ft intervals thereafter using a split spoon sampler (ASTM D1586 “Standard Test Method for Standard Penetration Test (SPT) and Split-Barrel Sampling of Soils”). The soil samples obtained from the exploration program were visually observed in the field by the NEAS field representative and preserved for review by a Geologist and possible laboratory testing. Standard Penetration Tests (SPT) were conducted using a CME auto hammer that has been calibrated to be 81.8% efficient as indicated on the boring logs. When bedrock was encountered, rock cores were collected in 5.0-ft runs utilizing an NQ2, triple tube, core barrel with water as the circulating fluid.

Field boring logs were prepared by drilling personnel, and included lithological description, SPT results recorded as blows per 6-inch increment of penetration, and estimated unconfined shear strength values on specimens exhibiting cohesion (estimated by means of hand-penetrometer). Groundwater level observations were recorded both during and after the completion of drilling. These groundwater level observations are included on the individual boring logs. After completing the borings, the boreholes were backfilled with either auger cuttings, grout, or a combination of these materials.

Location (Sta/Offset)

Northing Easting Elevation

(NAVD 88) (ft) Depth (ft) Structure

Notes:

1. As-drilled exploration location (Kentucky South, NAD83) and corresponding ground surface elevation interpolated from the topographic survey data included in USACE’s Topographic Survey of Shepherd Street, Cumberland, KY., dated October 14, 2016.

1444.0

1443.5

27.0 Rear Abutment

B-002-0-16 11+67, 5' LT 1886576.946

S-001-0-16 11+67, 30' RT 1886550.686 2448049.133 1443.5 21.3 Forward Abutment

Forward Abutment

Boring ID

B-001-0-16 10+74, 17' LT 1886522.386

24.52448026.029

2447949.357

City of Cumberland, Kentucky

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3.2. Laboratory Testing Program

The laboratory testing program consisted of classification testing, unconfined compressive strength of rock cores, slake durability testing, and moisture content determinations. The individual laboratory data sheets and results are included in Appendix B. Additionally, where possible, data from the laboratory testing program was incorporated onto the final borings logs. Soil samples are retained at the laboratory for 60 days following report submittal, after which time they will be discarded.

3.2.1. Classification Testing

Representative soil samples were selected for index properties (Atterberg Limits) and gradation testing for classification purposes on approximately 40% of the samples. At each boring location, samples were selected for testing with the intent of identification and classification of all significant soil units. Soils not selected for testing were compared to laboratory tested samples/strata and classified visually. Moisture content testing was conducted on all samples. The laboratory testing was performed in general accordance with applicable ASTM specifications.

A final classification of the soil strata was made in accordance with ASTM D 2487 “Standard Practice for Classification of soils for Engineering Purposes (Unified Soil Classification System) once laboratory test results became available. The results of the soil classification are presented on the boring logs in Appendix B.

3.2.2. Standard Penetration Test Results

Standard Penetration Tests and split-barrel (commonly known as split-spoon) sampling of soils were performed at varying intervals (i.e., 2.5-ft or 5.0-ft intervals) in the project borings performed. To account for the high efficiency (automatic) hammers used during SPT sampling, field SPT N-values were converted based on the calibrated efficiency (energy ratio) of the specific drill rig's hammer. Field N-values were converted to an equivalent rod energy of 60% (N60) for use in analysis or for correlation purposes. The resulting N60 values are presented on the boring logs provided in Appendix B.

3.2.3. Streambed Grain Size Distribution

At the approximate streambed elevation in Borings B-001-0-16 and B-002-0-16, SPT sampling was performed to obtain representative samples of potential streambed soils. Based on the material encountered, each identified strata were selected for grain size distribution testing to develop D95 and D50 values (i.e., the diameter in the particle-size distribution curve corresponding to 95% and 50% finer) for use in scour analysis. The calculated D95 and D50 values are presented in Table 2 below and grain size distribution charts for both borings are provided in Appendix B.

Table 2: Streambed Grain Size Analysis Results

Sample ID Sample Depth

(ft) Elevation

(NAVD 88) (ft) Classification D95 (mm) D50 (mm)

Notes:

1.

31.043 0.270

B-001-0-16 SS-5 15.0 - 16.3 1429.0 - 1427.7 Silty Sand with Gravel (SM) 22.712 0.272

B-001-0-16 SS-4 10.0 - 11.5 1434.0 - 1432.5 Silty Sand with Gravel (SM)

Boring ID

Ground surface elevation interpolated from the topographic survey data included in USACE’s Topographic Survey of Shepherd Street, Cumberland, KY., dated October 14, 2016.

23.535 0.374

B-002-0-16 SS-4 10.0 - 11.5 1433.5 - 1432.0 Silty Sand with Gravel (SM) 19.405 0.361

B-002-0-16 SS-2 5.0 - 6.5 1438.5 - 1437.0 Silty Sand with Gravel (SM)

City of Cumberland, Kentucky

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3.2.4. Unconfined Compressive Strength Of Rock Cores

An Unconfined Compressive Strength of a Rock Core Test was conducted in accordance with ASTM D 7012 "Standard Test Methods for Compressive Strength and Elastic Moduli of Intact Rock Core Specimens under Varying States of Stress and Temperatures" on one rock core sample obtained during the exploration program. The sample tested was obtained from boring B-001-0-16 at a depth of 20.3 to

20.7 ft bgs (approximate elevations 1423.7 to 1423.3 ft amsl). The rock is classified as moderately strong, gray Shale. The Unconfined Compressive Strength of a Rock Core Test results are shown in Table 3 below and provided in Appendix B.

Table 3: Unconfined Compressive Strength of a Rock Core Test Results

3.2.5. Slake Durability Test Results

Slake Durability Tests were conducted in accordance with ASTM D 4644 "Standard Test Method for Slake Durability of Shales and Other Similar Weak Rocks" on two sample samples of rock obtained within the rock core runs performed as part of the exploration program. The samples tested were obtained from a depth of 17 to 19 ft bgs (approximate elevations 1427.0 to 1425.0 ft amsl) in Boring B-001-0-16 and at a depth of 18.5 to 19.5 ft bgs (approximate elevations 1425.0 to 1424.0 ft amsl) in Boring B-002-016. The rock is classified as dark gray or gray Shale. The Slake Durability Tests results are shown in Table 4 below and provided in Appendix B.

Table 4: Slake Durability Test Results

4. GEOTECHNICAL FINDINGS

The subsurface conditions encountered during NEAS’s explorations are described in the following subsections and on each boring log presented in Appendix B. The boring logs represent NEAS’s interpretation of the subsurface conditions encountered at each boring location based on our site observations, field logs, visual review of the soil samples by NEAS's geologist, and laboratory test results.

The lines designating the interfaces between various soil strata on the boring logs represent the approximate interface location; the actual transition between strata may be gradual and indistinct. The subsurface soil and groundwater characterizations included herein, including summary test data, are based on the subsurface findings from the geotechnical explorations performed by NEAS as part of the referenced project, results of available historical explorations, and consideration of the geological history of the site.

4.1. Subsurface Conditions

The subsurface profile at the bridge replacement site is generally consistent with the geological model for the project in regards to the materials encountered. The subsurface profile within the proposed project area consists of surficial materials comprised of an existing pavement section, underlain by 4 to 7 ft of

Depth of Sample (ft)

Classification Moisture

Content (%) Dry Unit Weight

(pcf)

Unconfined Compressive Strength

(psi) Strain (%)

0.9%

Boring Number

B-001-0-16 20.3 - 20.7 Gray, Shale 0.9 5520162.6

Sample ID Sample Depth

(ft) Classification

Slake Durability Index (Id2)

Retained Material Type

43.5% T2 - Retained material consists of large and small pieces.

B-002-0-16 NQ2-1 18.5 - 19.5 Gray, Shale 92.2% T1 - Retained pieces remain virtually unchanged.

Boring ID

B-001-0-16 NQ2-1 17.0 - 19.0 Dark gray, Shale

City of Cumberland, Kentucky

- 9 - NEAS Project 16-0156 possible fill soils comprised of silt and sand mixtures over natural alluvial soils to depths ranging from 14 to 21 ft bgs (approximate elevations 1429.5 ft to 1422.5 ft amsl). Bedrock consisting of shale and shale interbeded with siltstone was encountered immediately below the natural soils within each borings and geotechnical sounding performed. The possible fill soils generally consisted of various mixtures of sand, silt and gravel with either a consistency of medium stiff (cohesive mixtures) or a relative density of medium dense to dense (non-cohesive mixtures). The natural alluvial soils generally encountered between depths of 4 and 21 ft bgs were comprised of medium dense to very dense silty sands.

4.1.1. Overburden Soil

At the proposed bridge site, two different materials were encountered below the existing pavement sections. In general, the overburden materials consisted of: 1) possible fill soils; and, 2) natural alluvial deposited soil. These materials and the general profile is further described below.

Soil visually identified as possible fill was encountered in each boring (B-001-0-16 and B-002-0-16).

These possible fill soils were encountered immediately below the surficial materials and extended to depths ranging from 4 to 7 ft bgs (approximate elevations 1439.5 to 1437.0 ft amsl). Based on a visual review of the possible fill samples obtained, the fill at the site is generally comprised of sand with silt and gravel (SW-SM) or silt with sand (ML). With respect to the soil strength of the sand with silt and gravel possible fill recovered, the soil can be described as having a relative density of medium dense to dense correlating to converted SPT-N values (N60) of 12 and 33 blows per foot (bpf). With respect to the relative consistency of the encountered silt with sand possible fill recovered, the soil was medium stiff correlating to an N60 value of 5 bpf.

The soil stratum encountered immediately beneath the possible fill consisted of relatively coarse grained alluvial deposited soils. These soils were encountered at depths ranging from 4 to 7 ft bgs (approximate elevations 1439.5 to 1437.0 ft amsl) and extended to bedrock in each boring. The coarse grained deposits in this stratum are primarily comprised of sand with variable percentages of gravel, silt and clay. The soil in this strata is generally classified on the boring logs as silty sand with gravel (SM). With respects to the relative density of the alluvial soil recovered, the descriptions varied from medium dense to very dense, correlating to N60 values between 25 bpf and SPT refusal (where less than 6 inches of penetration is achieved for 50 blows). Natural moisture contents of the alluvial soil ranged from 8 to 12 percent.

4.1.2. Groundwater

Groundwater measurements were taken during the boring drilling procedures and immediately following the completion of each borehole. Groundwater was observed during drilling in each boring performed as part of the referenced project. Based on the project borings, groundwater was encountered at depths of 8.0 and 9.0 ft bgs (elevations 1436.0 and 1434.5 feet amsl) in Borings B-001-0-16 and B-002-0-16, respectively. It should be noted that groundwater is affected by many hydrologic characteristics in the area and may vary from those measured at the time of the exploration. The specific groundwater readings are included on the boring logs located within Appendix B.

4.1.3. Bedrock

Bedrock was encountered in each boring performed at project site and was classified as shale or interbeded shale and siltstone. Based on each of the borings as well as the geotechnical rockline sounding performed at the site, the bedrock surface was present at depths between about 14 and 21 feet bgs. Based on the estimated bedrock surface across the bridge site it appears that the bedrock surface generally slopes downward from west to east and varies in elevation of about 1429.5 to 1422.5 feet amsl.

City of Cumberland, Kentucky

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Rock coring was performed at each of the borings once auger refusal was encountered. Based on the rock core samples obtained from the boreholes, the bedrock is described as highly weathered to slightly weathered with a relative strength ranging from very weak to strong. Recovery of the bedrock core samples ranged from 63 to 90 percent while and Rock Quality Designation (RQD) values ranged from 45 to 94 percent. A summary of the bedrock data is presented below in Table 3.

Table 5: Bedrock Summary

5. ANALYSES AND RECOMMENDATIONS

We understand that the existing 39-ft long, single span Shepherd Street bridge structure, spanning Looney Creek on Shepherd Street in Harlan County, Kentucky is proposed to be replaced with a new structure. It is our understanding that the likely replacement structure will be a single span pre-cast composite box beam superstructure on semi-integral abutment supported by the natural subsurface material through the use of a deep foundation system. For analysis purposes, it is assumed that the proposed bearing elevation for each abutment will be 1437.0 ft and 1434.5 ft amsl at the rear and forward abutment, respectively.

A foundation review was completed for a deep foundation pile system for the referenced bridge. A deep pile foundation will be designed according to LRFD criteria. A shallow foundation system was not reviewed as the depth to top of bedrock from the proposed finish grade elevation ranges from 14.0 to

22.5 ft; which extends near or below the depth (from proposed grade) at which KYTC generally prefers the use of deep foundations (20 ft) in accordance with GT-605-1 of the GGM. Furthermore, the use of cast-in-place (CIP) pipe piles were not reviewed because the encountered overburden soils may make it difficult to drive CIP pile to sufficient depths (pile should be a minimum of 10 feet below the bottom of the pile cap). The computer program Driven developed by the Federal Highway Administration was used to estimate the driven pile length needed to achieve the required nominal bearing resistance to support the total factored load for a single pile. Input information for the Driven program was based on the soil characteristics gathered during the geotechnical exploration (i.e., SPT results, laboratory test results, etc.)

and our geotechnical experience. Tables 6 and 7 in Section 5.1 of this report present each soil strata and their engineering properties that were used in the pile foundation review. Uplift resistance of the deep foundation (a single pile) was also evaluated in accordance with LRFD criteria.

Based on our evaluation of the subsurface conditions and our geotechnical engineering analysis of the proposed bridge replacement project, it is our opinion that the bridge foundations can be supported on HP12X53 steel "H" piles placed within pre-bored holes, embedded into bedrock and encased in grout. It is our opinion that, piles installed in accordance with the recommendations provided within this report, will be point bearing piles seated in shale bedrock or in the weathered shale directly above the shale bedrock at elevations ranging from 1420 to 1426 ft amsl. At the indicated pile tip elevations it is anticipated that the piles will bear on sound bedrock that will provide sufficient resistance for the design loads. With respect to global stability and settlement at the proposed bridge replacement location, as approach embankments have been fully formed since the original construction of the bridge and there are no planned significant changes to their configuration, the existing slopes are expected to remain stable and settlement will be minimal. It should be noted that an evaluation of pile drivability is not applicable to

Bedrock Depth (ft)

Bedrock Elevation (ft)

Bedrock Recovery (%)

Bedrock RQD

63 (NQ2-1) 45 (NQ2-1)

98 (NQ2‐2) 94 (NQ2‐2)

90 (NQ2-1) 64 (NQ2-1)

Boring ID

B-001-0-16 16.3 1427.7

B-002-0-16 14.0 1429.5

S-001-0-16 21.0 1422.5 - -

City of Cumberland, Kentucky

- 11 - NEAS Project 16-0156 the recommended pile installation method (pre-bored hole) and therefore is not presented within this report.

5.1. Soil Profile for Analysis

For analysis purposes, each substructure location (boring log) was reviewed and a generalized material profile was developed for analysis. Utilizing the generalized soil profile, engineering properties for each soil strata were estimated based on their field (i.e., SPT N60 values, hand penetrometer values, etc.) and laboratory (i.e., Atterberg Limits, grain size, etc.) test results using our experience as well as correlations provided in published engineering manuals, research reports and guidance documents. The developed soil profile and estimated engineering soil properties used in our analysis is summarized per substructure location (per boring) within Tables 6 and 7, below.

Table 6: Rear Abutment - Soil Profile and Estimated Engineering Properties (B-001-0-16)

Table 7: Forward Abutment - Soil Profile and Estimated Engineering Properties (B-002-0-16 & S-001-0-16)

5.2. Bridge Foundation Analysis

5.2.1. Deep Foundation Analysis

Based on the determined soil profile and our estimated engineering soil properties, a pile analysis was performed using the computer program Driven to determine the estimated nominal geotechnical resistance of a single pile at each substructure location (Driven Results can be found in Appendix C).The calculated required nominal pile bearing resistance was determined in accordance with Section 10.7.3.8.6 of the LRFD BDS (AASHTO, 2014). Based on the results of our analysis, a single HP12x53 pile is

Notes:

1. Values calculated from Terzaghi and Peck (1967) if N1 60<52, else Stroud and Butler (1975) was used.

2. Values interpreted from Terzaghi and Peck (1967)

3. Value based on estimated Shear Strength values for weathered, low RQD shale

4. Value based on Unconfined Compressive Strength of Rock Core test results from B-001-0-16 NQ2-1 rock core.

164 -

164 -

Elevation (1437 ft - 1427.7 ft)

Weathered Shale Bedrock(3)

Elevation (1427.7 - 1425.2)

Moderately Strong Shale Bedrock(4)

Elevation (1425.2 - 1419.0)

Unit Weight (pcf)

Effective

Friction Angle(2)

(degrees)

Sand with Silt and Gravel (SW-SM)

Soil Description

Elevation (1444 ft - 1437 ft) Silty Sand with Gravel (SM)

Undrained Shear

Strength(1)

(psf)

Effective Cohesion

(psf)

Weak Rock

Weak Rock

0.00018

0.00005

Rock Mass Modulus, Em

(psi)

N/A

N/A

8,550

375,000

Shepherd Street Bridge: Rear Abutment, B-001-0-16

L-pile p-y Model

Sand (Reese)

Sand (Reese) p-y Modulus of Subgrade

Reaction, k or krm

0 0

0 0

72,000 -

397,440 -

Notes:

1. Values calculated from Terzaghi and Peck (1967) if N1 60<52, else Stroud and Butler (1975) was used.

2. Values interpreted from Terzaghi and Peck (1967)

3. Value based on estimated Shear Strength values for weathered, low RQD shale

4. Value based on Unconfined Compressive Strength of Rock Core test results from B-001-0-16 NQ2-1 rock core.

9,000

375,000

Shepherd Street Bridge: Forward Abutment, B-002-0-16 & S-001-0-16

L-pile p-y Model p-y Modulus of Subgrade

Reaction, k or krm

Rock Mass Modulus, Em

(psi)

Sand (Reese) 26 N/A

Sand (Reese) 245 N/A

Weak Rock

Weak Rock

0.00018

0.00005

600 75

72,000 -

397,440 -

Undrained Shear

Strength(1)

(psf)

Effective Cohesion

(psf)

Unit Weight (pcf)

Effective

Friction Angle(2)

(degrees)

Silt with Sand (ML)

Soil Description

Elevation (1443.5 ft - 1439.5 ft) Silt Sand with Gravel (SM)

Elevation (1439.5 ft - 1422.5 ft)

Weathered Shale Bedrock(3)

Elevation (1422.5 - 1420.0)

Moderately Strong Shale Bedrock(4)

Elevation (1420.0 - 1417.0)

164 -

164 -

City of Cumberland, Kentucky

- 12 - NEAS Project 16-0156 expected to achieve a nominal geotechnical pile resistance of 29 kips and 40 kips within the overburden soils (prior to reaching bedrock) at the rear and forward abutment locations, respectively.

Based on the maximum total factored loads on a single pile provided by Woolpert via email on March 22, 2017, it was concluded that an HP12X53 pile would not provided adequate geotechnical resistance within the overburden soil and should extend to bedrock. Based on the borings and the geotechnical rockline sounding performed at the project site, it is anticipated that bedrock will be encountered at approximate elevations of: 1) 1429 ft and 1432 ft amsl on the western (left) side of the rear and forward abutments, respectively; and, 2) 1423 ft and 1425 ft amsl on the eastern (right) side of rear and forward abutments, respectively. As a result of our analysis, it was determined that the proposed piles will be point bearing in bedrock and therefore, the factored geotechnical resistance of a single pile is controlled by the maximum factored structural resistance of the recommended pile.

5.2.2. Pile Uplift Resistance

The uplift resistance of HP piles bearing on bedrock is calculated in accordance with LRFD 10.7.3.10.

The static analysis method is used to determine the nominal uplift resistance due to side resistance of the overburden soils; however, as the piles are to be placed in pre-bored holes, embedded into bedrock and encased in grout, the side resistance of the overburden soil was ignored in our analysis. NEAS's analysis for uplift resistance was performed based on: 1) the Cumberland, Kentucky - Shepherd Street Bridge Replacement over Looney Creek - 60% Site Plans dated January 27, 2017 provided by Woolpert on January 30, 2017; 2) Sections 10.7.3.10 of AASHTO's LRFD BDS; 3) the determined soil profile and our estimated engineering soil properties; 4) an 24-inch diameter pre-bored hole embedded 3 ft into the encountered bedrock; and, 5) the pile is encased/set in Non-Shrink Grout in accordance with Section 601.03.03B of KYTC's Standard Specifications for Road and Bridge Construction (7-day compressive strength of 4,500 psi). The results of our analysis indicate that a single pile (HP12x53) installed as indicated above, will provide a total factored uplift resistance of 48.9 kips.

5.3. Foundation Recommendations

We recommend that a pile foundation be used for support on this bridge, with the piles consisting of HP12X53 steel "H" pile placed in pre-bored holes, embedded into bedrock and encased/set in grout. The HP12X53 piles are recommend to: 1) have a minimum pre-bored hole diameter of 24-inches; 2) have a minimum embedment of 3 ft within bedrock determined to be below the depth of scour; and, 3) extend a minimum of 10 ft below bottom of pile cap elevation. Furthermore; it is recommended that the piles be encased/set in Non-Shrink Grout in accordance with Section 601.03.03B of KYTC's Standard Specifications for Road and Bridge Construction (7-day compressive strength of 4,500 psi).

As indicated in section 5.2.1 of this report, the factored resistance for piles embedded into bedrock is typically controlled by the structural resistance of the pile as opposed to bearing resistance for friction piles; therefore, the nominal resistance of any single HP12X53 pile is anticipated to be 760 kips (maximum nominal structural resistance). This nominal pile resistance (single pile) for an HP12X53 pile may be used to support the abutment foundations under the following conditions: 1) piles are installed in accordance with recommendations provided within this report; 2) the piles are axially loaded pile with negligible moment; 3) steel piles have a yield strength of 50 kips per square inch (ksi); 4) assumed no appreciable loss of section due to deterioration throughout the life of the structure; 5) the appropriate structural resistance factor (based on Section 6.5.4.2 of the LRFD BDS) is applied to the indicated nominal pile resistance to obtain the total factored pile resistance considering the pile installation method;

and, 6) the piles are fully braced along their length. These values should not be used for piles that are subjected to bending moments or are not supported by soil for their entire length (i.e., no soil scour below the pile cap). If it is determined any of these conditions are not satisfied at the referenced bridge site, the

City of Cumberland, Kentucky

- 13 - NEAS Project 16-0156 pile's maximum factored structural resistance should be re-evaluated. With respect to potential scour, it is recommended that abutment piles achieve a minimum embedment of 3 ft into bedrock at a depth below the determined scour elevation

With a minimum embedment of 3 ft into bedrock (at a depth below scour) and a minimum pile embedment of 10 ft below bottom of pile cap elevation, pile tip elevations are estimated to range from about 1420 to 1426 ft amsl. Pile lengths at the left end, center and right end of both abutments based on:

1) our Deep Foundation Analysis (presented in Section 5.2.1); 2) the assumed bottom of pile cap elevations for each abutment; and, 3) the anticipated bedrock profile along the length of the abutment based on the performed explorations, are shown in Table 8.

Table 8: Estimated Pile Lengths Summary

Furthermore, it is our opinion that it will be necessary to case the pile shafts as they are being drilled to maintain the pile shaft walls. Following placement of the casing, we recommend that the pile be placed within the shaft and the indicated non-shrink grout be tremmied from the bottom of the shaft to displace any water or sand/silt at the shaft bottom. We recommend that the grout completely encase the pile to the top of the pile shaft and the casing removed once the grout is tremmied to the top of the drilled shaft.

Following casing removal, it is recommended that any subsidence/permeation of the grouted shaft be backfilled or "topped-off" with grout back to the top of the pre-bored hole.

6. QUALIFICATIONS

This investigation was performed in accordance with accepted geotechnical engineering practice for the purpose of characterizing the subsurface conditions at the Shepherd Street Bridge replacement site in Cumberland, KY. This report has been prepared for Woolpert, the USACE and their design consultants to be used solely in evaluating the soils underlying the bridge site and presenting geotechnical engineering recommendations specific to this project. The assessment of general site environmental conditions or the presence of pollutants in the soil, rock and groundwater of the site was beyond the scope of this geotechnical exploration. Our recommendations are based on the results of our field explorations, laboratory tests results from representative soil samples, and geotechnical engineering analyses. The results of the field explorations and laboratory tests, which form the basis of our recommendations, are presented in the appendices as noted. This report does not reflect any variations that may occur between the borings or elsewhere on the site, or variations whose nature and extent may not become evident until a later stage of construction. In the event that any changes in the nature, design or location of the proposed bridge project is made, the conclusions and recommendations contained in this report should not be

Notes:

1. Geotechnical Pile Tip Elevation equals the assumed top of rock elevation minus 3-ft minimum embedment into bedrock. It should also be noted that the indicated Geotechnical Pile Tip Elevations are estimated under the assumption that the indicated top of rock elevations are below the depth of scour.

Pile Type Location Along

Abutment Bottom of Pile Cap

Elevation (ft) Assumed Top of

Rock Elevation (ft) Geotechnical Pile

Tip Elevation(1) (ft)

HP12X53 Center 1437.0 1425.5 1422.5

HP12X53 Left 1437.0 1429.2 1426.2

HP12X53 Left 1434.5 1432.0 1424.5

1434.5 1425.5 1422.5

HP12X53 Center 1434.5 1429.0 1424.5

12.0

Rear Abutment Summary

Forward Abutment Summary

Geotechnical Pile Length (ft)

10.8

14.5

10.0

10.0

1437.0 1423.6 1420.6 16.4HP12X53 Right

HP12X53 Right

City of Cumberland, Kentucky

- 14 - NEAS Project 16-0156 considered valid until they are reviewed, and have been modified or verified in writing by a geotechnical engineer.

It has been a pleasure to be of service to Woolpert in performing this geotechnical exploration for the Shepherd Street Bridge replacement project. Please call if there are any questions, or if we can be of further service.

Respectfully Submitted, Brendan P. Andrews, P.E. Kevin C. Arens, E.I.

Geotechnical Engineer Staff Geotechnical Engineer

City of Cumberland, Kentucky

- 15 - NEAS Project 16-0156

REFERENCES

AASHTO. (2014). LRFD Bridge Design Specifications. Washington, D.C.: American Association of State Highway and Transportation Officials.

FEMA. (2016). National Flood Hazard Layer kmz v3.0. Federal Emergency Management Agency.

KGS. (2015). Kentucky's Physiographic Regions: Kentucky Geological Survey, University of Kentucky.

Lexington, KY.

KGS. (2016). Kentucky Geologic Map Information Service. Lexington: University of Kentucky.

KYTC [1]. (2005). Structural Design Guidance Manual. Frankfort, KY: Kentucky Transportation Cabinet: Division of Structural Design. Retrieved from http://transportation.ky.gov/Structural- Design/Manuals/Chapters.pdf

KYTC [2]. (2005). Geotechnical Guidance Manual. Frankfort, KY: Kentucky Transportation Cabinet:

Geotechnical Branch. Retrieved from http://transportation.ky.gov/Organizational- Resources/Policy%20Manuals%20Library/Geotechnical.pdf

USDA. (2015, September). Web Soil Survey. Retrieved from http://websoilsurvey.nrcs.usda.gov

USGS & KGS. (1988, June). Geologic Units of Kentucky. ohgeol.kmz. United States Geologic Survey.

APPENDIX A

SOIL BORING LOCATION PLAN

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SCALE: J-•IO:

SOIL BORING LOCATION PLAN

SHEPHERD STREET BRIDGE

CUMBERLAND, KY

Ea st

M ai n St re et

Shepherd Street

M ar tin A ve nu e

APPENDIX B

SOIL BORING LOGS & LABORATORY TEST RESULTS

1443.7 1443.0

1437.0

1427.7

1422.4

1417.0

SW-SM

(V)

SW-SM

(V)

SM (V)

SM

SM

CORE

CORE

SS-1

SS-2

SS-3

SS-4

SS-5

NQ2-1

NQ2-1

50/4"

3.0", ASPHALT

9.0", GRANULAR BASE

MEDIUM DENSE TO DENSE, BROWN, DARK BROWN,

AND ORANGISH BROWN, WELL-GRADED SAND WITH

SILT AND GRAVEL, TRACE CLAY, DAMP

MEDIUM DENSE TO VERY DENSE, BROWN AND

ORANGISH BROWN, SILTY SAND WITH GRAVEL,

TRACE CLAY, MOIST

@7.5'; SS-3 CONTAINS 1.0" LIMESTONE FRAGMENT

@15.0'; SS-5 BECOMES BROWN AND BLACK, SILTY

SAND, LITTLE GRAVEL

SHALE, DARK GRAY TO BLACK, MODERATELY

WEATHERED, VERY WEAK TO WEAK, LAMINATED,

FISSILE, FOSSILIFEROUS, BEDDING AND JOINT

DISCONTINUITIES: LOW ANGLE, MODERATELY

FRACTURED, HIGHLY FRACTURED FROM 17.0' - 17.5'

AND 19.5' - 19.8', NARROW TO OPEN, SLIGHTLY TO VERY

ROUGH, DISINTIGRATED TO

BLOCKY/DISTURBED/SEAMY, GOOD SURFACE

CONDITION; RQD 45%, REC 62.7%.

INTERBEDDED SILTSTONE (85%) AND SHALE (15%),

RQD 93.8%, REC. 98.5%;

SILTSTONE, LIGHT GRAY TO GRAY, SLIGHTLY

WEATHERED, STRONG, LAMINATED TO THIN BEDDED,

FOSSILIFEROUS, CONTAINS BROWN STRONG SHALE

INCLUSIONS, BEDDING DISCONTINUITIES: LOW ANGLE,

SLIGHTLY FRACTURED, HIGHLY FRACTURED FROM 26.8'

- 27.0', NARROW TO OPEN, SLIGHTLY ROUGH, BLOCKY,

GOOD SURFACE CONDITION;

SHALE, DARK GRAY, MODERATELY STRONG.

NP

NP

NP

NP

NP

NP

ENERGY RATIO (%): 81.8

DRILLING METHOD: 3.25" HSA / NQ2

START: 12/13/16 END: 12/13/16

SAMPLING FIRM / LOGGER: NEAS / ASHBAUGH

DRILLING FIRM / OPERATOR: NEAS / ASHBAUGH

EOB: 27.0 ft.

HAMMER: CME AUTOMATIC

DRILL RIG: CME 55

CALIBRATION DATE: 12/3/15

ALIGNMENT:

SAMPLING METHOD: SPT / NQ2

PAGE

EXPLORATION ID

B-001-0-16

1444.0

ELEVATION: 1444.0 (MSL)

PROJECT: SHEPHERD ST. BRIDGE STATION / OFFSET: 10+74, 17.0 LT

COORD: 1886522.386 N, 2447949.357 E

CLIENT: WOOLPERT, INC.

TYPE: BRIDGE

REC

ELEV. USCS

CLASSGR

DEPTHS

SAMPLE

ID

SPT/

RQD CS MS FS SI CL

MATERIAL DESCRIPTION

AND NOTES

HOLE

SEALEDLL PL PI WC

HP

(tsf)

GRADATION(%) ATTERBERG

N60

S T

A N

D A

R D

O D

O T

S O

IL

B

O R

IN

G

L O

G

8.

X

1)

O H

D O

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D T

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3:

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LU

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B U

S

LA

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IV

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JE

C

T S

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IV

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O

IL

P R

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P H

E R

D S

T

B R

ID

G

E \G

IN

T

F

IL

E S

\U S

A C

E S

H E

P H

E R

D S

T

B R

ID

G

E .G

P J

NOTES: GROUNDWATER ENCOUNTERED AT 8.0' DURING DRILLING. HOLE DID NOT CAVE.

ABANDONMENT METHODS, MATERIALS, QUANTITIES: PLACED 0.5 BAG ASPHALT PATCH; PUMPED 90 LB. CEMENT

EOB

TR

1443.1 1442.7

1439.5

1429.5

1419.0

ML (V)

SM

SM (V)

SM

CORE

3.75 - 4.5+

SS-1

SS-2

SS-3

SS-4

SS-5

NQ2-1

50/3"

5.0", ASPHALT

5.0", GRANULAR BASE

VERY STIFF TO HARD, BROWN AND GRAY, SILT WITH

SAND, TRACE GRAVEL, TRACE CLAY, MOIST

DENSE, BROWN, SILTY SAND WITH GRAVEL, TRACE

CLAY, DAMP TO MOIST

@5.0'; SS-2 AND SS-3 CONTAIN ANTHRACITE COAL

FRAGMENTS

@14.0'; SS-5 NO RECOVERY

INTERBEDDED SHALE (72%) AND SILTSTONE (28%),

RQD 64%, REC. 90%;

SHALE, DARK GRAY, MODERATELY TO HIGHLY

WEATHERED, MODERATELY STRONG, LAMINATED TO

VERY THIN BEDDED, FISSILE, BEDDING

DISCONTINUITIES: LOW ANGLE, JOINT

DISCONTINUITIES: HIGH ANGLE FROM 16.8' -…