GEOTECHNICAL REPORT Mainline Roadway Interstate 57 and Interstate 294 Interchange Project IDOT Job: P-91-186-08 (PTB 146, ITEM 1) Cook County,

Prepared by:

Geo Services, Inc. 805 Amherst Court Suite 204 Naperville, Illinois 60565 (630) 305-9186

JOB NO. 08015

January 2009

January 30, 2009

T. Y. Lin International 200 South Wacker Drive Suite 1400 , Illinois 60606

Attn: Mr. Dean Kiesling Job No. 08015

Re: Geotechnical Report Interstate 57 Mainline Roadway Report - Kedzie Avenue to 147th Street Interstate 294 and Interstate 57 Interchange Project Cook County, Illinois IDOT Job Number: P-91-186-08 PTB 146, Item # 1

Dear Mr. Kiesling:

The following report presents the geotechnical analysis and recommendations for the widening of Interstate 57 (I-57) for the proposed Interstate I-57 and Interstate 294 (I- 294) interchange from approximately Kedzie Avenue to 147th Street. Geo Services, Inc. (GSI) completed a total of fifty-two (52) roadway soil borings (I57 S-01 through I57 S- 52) at the site. In addition, thirty-four (34) cores were retrieved and used for the pavement evaluation. Copies of these boring logs, including pavement core information and soil boring location diagrams are included in this report.

If there are any questions regarding the information submitted herein, please do not hesitate to contact us.

Very truly yours,

GEO SERVICES, Inc.

Alex Barlan, E.I.T. Andrew J. Ptak, P.E. Staff/Field Engineer Office Manager enc.

805 Amherst Court, Suite 204  Naperville, IL 60565-3448  Phone (630) 305-9186  Fax (630) 355-2838 www.geoservicesinc.net

TABLE OF CONTENTS

INTRODUCTION...... 2

PROJECT DESCRIPTION...... 2

GEOLOGY ...... 3

CLIMATIC CONDITIONS...... 4

SUBSURFACE INVESTIGATION PROCEDURES ...... 5

LAB TESTING PROGRAM...... 5

SUBSURFACE CONDITIONS...... 6

PAVEMENT CONDITIONS...... 7

WATER TABLE CONDITIONS...... 7

ANALYSIS AND RECOMMENDATIONS ...... 7

GENERAL QUALIFICATIONS ...... 9

APPENDIX A – Site Location Map APPENDIX B – Soil Boring Location Diagrams APPENDIX C – Boring Logs APPENDIX D – Pavement Core Summary APPENDIX E – Pavement Core Photo Logs APPENDIX F – USDA National Resources Conservation Service Soil Survey Map APPENDIX G – IDOT BDE 508A Sheets APPENDIX H – IDOT Textural Triangle

MAINLINE ROADWAY GEOTECHNICAL REPORT IDOT CONTRACT NO: P-91-186-08 I-57 AND I-294 INTERCHANGE PROJECT I-57 MAINLINE ROADWAY, COOK COUNTY, IL GSI PROJECT NUMBER 08015 PTB 146, ITEM 1

INTRODUCTION

This report presents the results of the geotechnical investigation for the proposed mainline pavement widening along Interstate 57 for the Interstate 57 (I-57) and Interstate 294 (I-294) Interchange Project between approximately Kedzie Avenue and 147th Street in Cook County, Illinois, IDOT Project Number: P-91-186-08. The results of the fifty-two (52) roadway borings (I57 S-01 through I57 S-52) and thirty-four (34) cores completed by Geo Services, Inc., along with a site location map, soil boring location diagrams and laboratory test results, are included with this report.

Boring locations were selected by Geo Services, Inc. and were reviewed and approved by T.Y. Lin International and the Illinois Department of Transportation (IDOT). Boring locations were laid out in the field by Geo Services, Inc personnel at the proposed locations. Elevations were estimated from a topographic map provided by T.Y. Lin International, and the as-drilled locations are illustrated on the soil boring location diagrams in Appendix B.

This report includes recommendations pertaining to the design and construction of the roadway widening, a description of soil, rock and groundwater conditions, general construction considerations for the site, location diagram, boring logs, and pavement core logs.

PROJECT DESCRIPTION

The existing I-57 roadway is an access-controlled interstate highway carrying three through-lanes of traffic in both northbound and southbound directions. Access to and from the interstate, within the project area, are through entrance/egress ramps at 147th Street. Bridge structures at 147th Street and I-294 carry I-57 over these intersections. At the I-57 underpass, the Kedzie Avenue Bridge is proposed to be extended.

Proposed improvements to I-57 have yet to be finalized at the time this report was prepared; improvements may range from complete reconstruction of the expressway and the addition of a fourth lane of traffic in each direction or may be limited to patchwork, scarification and pavement overlay work. Work including the construction of new ramps to provide access and egress to I-294, the widening/reconstruction of the various grade separation structures and retaining walls and other ancillary structures will be addressed in separate reports.

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GEOLOGY

ISGS 20-ft Surficial Map for South Cook County: Surficial soils along the entire project corridor are generally identified as consisting of discontinuous layers of the Carmi Member of the Equality Formation which are underlain by soils belonging to the Wadsworth Till Member of the Wedron Formation. There is a small area identified near the far south end of the corridor where that may have thin discontinuous deposits of Parkland Sands. The Carmi Member soils generally consist of bedded silts and sands that accumulated in ancient glacial lakes and the Wadsworth Till soils generally consist of gray clayey and silty clay tills. These soils were deposited during Woodfordian Substage of the Wisconsinan glaciation between 12,500 to 22,000 years ago. The Parkland Sands consist of windblown dune deposits of fine-grained materials.

ISGS Circular #542 Stack Map: The 50-ft Stack Map confirms the soils in the vicinity of the project corridor are as identified above and that bedrock is in excess of 50-ft deep. A review of the ISGS Digital Water Well records for well logs immediately adjacent to the project corridor encountered bedrock within a depth range of 42.0-f to 57.0-ft (elevation 553 to 575). Borings performed from the bridge structural geotechnical reports performed for the same project as this investigation encountered bedrock typically in this elevation range.

ISGS Berg Circular #532: The far southwest end of the project corridor is noted to be located in an AX Zone then alternates between E and B1 Zones as it runs to the northeast. AX Zones are defined as an area with surficial deposits of alluvium deposits of a mixture of gravel, sand, silt, and clay deposited along streams and may be variable in composition and thickness. E Zones are defined as an area with relatively uniform impermeable silty or clayey till at least 50-ft thick with no evidence of interbedded sand and gravel. B1 Zones are defined as an area with less than 20-ft of sand and gravel deposits that are underlain by relatively impermeable till or bedrock.

USDA National Resources Conservation Service Soil Survey Database: The northern portion of the project corridor north of I-294 is noted to be in an unmapped area for which no data is available. Surficial soils in the southern portion of the corridor are noted to consist mostly of sandy loam to loam soils. None of the mapped soils are considered to be highly organic and only the Selma Loam (125A) and Gilford fine sandy loam (210A) soils, which make up approximately 24% of the soils located between I-294 to the north and to the south, are noted to be highly susceptible to frost action. These soils are identified in red on the Frost Action Map included in Appendix F.

US Fish & Wildlife Service Database: The project corridor is not noted to run through any naturally occurring wetland areas and the only nearby identified wetland area north of the I-57/294 interchange is a 0.9 acre Palustrine-Emergent wetland located approximately 300-ft north of I-57 and 100-ft east of I-294 that is noted to be seasonally flooded. There are four (4) small wetland areas located within 100-ft to 200-ft of the north side of I-57 between Kedzie Avenue and 155th street ranging in size from 0.3 to

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5.6 acres. These wetland areas are noted to generally consist of Palustrine-Forested wetlands that range from being semi-permanently to seasonally flooded.

ISGS Coal Mine & Seismic Maps: No historical coal mines are identified in the vicinity of the project corridor and it is noted to be located in a low seismic activity area.

In general, the geologic conditions are comparable to the soils encountered in the boring logs. The roadway borings presented in this report only went to a maximum depth of 10 feet, but the additional borings completed for the structural bridge reports for this project confirm the geology conditions above. Silty, clayey soils are typically encountered until an approximate depth of 50’ (approximate elevation of 565) where the soil transitions to bedrock.

CLIMATIC CONDITIONS

The climate within the area of this project fall within the temperate humid, continental range and is characterized by cold conditions in the winter and warm conditions in the summer. The winter average daily temperature is 25o F. The summer average temperature is 71o F and the summer average daily maximum temperature is 81o F. The total annual precipitation for this area is 35.8" with approximately 63% falling between April and September. The average seasonal snowfall for this area is 38.7".

Local Climatatological Data, as measured at O’Hare International Airport (ORD), for the three (3) month period prior to and during drilling, including total precipitation, average temperature and snowfall are summarized in the following Table 1 – Climate Conditions:

Table 1 – Climate Conditions

ppt (in) Temp (EF) Snow (in) MONTH-Yr Total Departure Average Departure Total Monthly From Norm Temp. From Norm Norm July-08 4.76 +1.25 74.0 +0.7 0.0 0.0 August-08 3.73 -0.89 72.7 +1.0 0.0 0.0 Sept-08 13.63 +10.36 66.2 +2.4 0.0 0.0 Oct-08 2.07e -0.64 52.7 +0.6 Trace 0.3 Nov-08 1.81e -1.2 39.2e 0.0 0.6 1.9

• e: estimated

Total precipitation during the three months preceding drilling was higher than normal with very heavy rainfalls in September. Temperatures were also higher than normal. During the period drilling was performed, total precipitation was less than normal and

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temperatures were above normal. Even with total precipitation levels slightly lower from October to December, the heavy precipitation levels in September are expected to generate higher surficial moisture content and lower strength than normal.

SUBSURFACE INVESTIGATION PROCEDURES

The borings were performed during the months of late October and early November, 2008, with a truck-mounted drilling rig and were advanced by means of hollow stem augers or rotary drilling techniques. Representative soil samples were obtained employing split spoon sampling procedures in accordance with AASHTO Method T-206. Samples obtained in the field were returned to our laboratory for further examination and testing.

Split spoon sampling involves driving a 2.0-inch outside diameter split-barrel sampler into the soil with a 140-pound weight falling freely through a distance of 30 inches. Blow counts are recorded at 6" intervals and the blow counts are shown on the boring logs. The number of blows required to advance the sampler the last 12 inches is termed the Standard Penetration Resistance (N). The N value is an indication of the relative density of the soil.

The pavement cores were performed from the 11th to the 16th of September, 2008 and December 11th, 2008 using a 4-inch diameter diamond bit core barrel and Milwaukee coring machine. The core was extended through the existing pavement to the underlying subbase materials below. Subbase materials were hand augured to the depth of subgrade or a maximum of 2-foot depth from the surface. Thicknesses for the pavement and subbase were recorded before pavement core holes were patched. Results are included with this report and can be found in the Pavement Core Summary, found in Appendix D.

LAB TESTING PROGRAM

The test procedures were performed in accordance with test procedures discussed in the IDOT Geotechnical Manual. All split-spoon samples obtained from the drilling operation were visually classified in the field. Cohesive samples were tested for unconfined compressive strength using an IDOT modified RIMAC test device and/or calibrated penetrometer in the field.

The soil testing program included performing water content, density and either unconfined compression and/or calibrated penetrometer tests on the cohesive samples recovered. Water content tests were performed on the non-cohesive samples recovered. These tests were performed upon representative portions of the samples obtained in the field. The results of the above testing, along with a visual classification of the material based upon both the Illinois textural classification and the AASHTO Soil

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Classification System, are indicated on the boring logs. In addition, unconfined compressive testing was performed on rock cores obtained from the field and are indicated on the rock core logs.

In addition to the general soils testing program, soil samples were tested for Atterberg Limits and Particle Size Analyses. Atterberg Limits were tested in compliance with AASSHTO T89/T90 and Particle Size Analyses were tested in compliance with AASHTO T80. The results of the additional testing can be found in the appendices and are summarized in Appendix G - BDE 508A Sheets

SUBSURFACE CONDITIONS

Roadway borings were generally taken from the shoulder areas approximately 3300 feet south of Kedzie Avenue to 1100 feet north of 147th Street. These borings indicated that the existing shoulder along the I-57 mainline is composed of 12.0-24.0 inches of asphalt. Underlying materials consisted primarily of silty loam and granular fill and brown and gray silty clay loam. These materials were underlain by more brown and gray silty clay loam or brown and gray clay interstratified with occasional stratum of sandy loams and granular material. Laboratory testing indicates that the naturally occurring silty clay loam found throughout the project area was classified as an A-6 or lean A-7 soil with a plasticity index ranging from 11 to 26. Moisture contents in the silty clay loam ranged were generally well below 25.0 per cent.

Some boreholes encountered buried topsoil. Boring S-10 (Station 211+00) had sandy topsoil at a depth of 4.0 – 5.5 feet. Boring S-14 (Station 217+00) had moderately wet, black topsoil encountered at a depth of 4.0 – 5.0 feet. Boring S-23 (Station 238+00) had wet, black topsoil found at a depth of 4.5 – 6.0 feet. Boring S-26 (Station 242+50) had sandy topsoil at a depth of 6.0 – 7.5 feet. Boring S-17 (Station 244+00) had sandy topsoil at a depth of 9.0 – 10.0 feet.

Borings I57 S-41 and S-43 were obtained along the existing ramp for northbound I-57 exiting to 147th Street. Boring S-41 showed a pavement consisting of 18.0 inches of asphalt over stiff gray and black clay loam fill. Moisture contents ranged from 13-19 per cent in this material. S-43 indicated 6.0 inches of asphalt over 8.0 inches of concrete underlain by very stiff to hard gray A-6 silty clay loam with a moisture content of 18 per cent over medium dense to dense silty loam.

Borings I57 S-45 and S-49 were taken along the existing entrance ramp from 147th Street to northbound I-57. Boring S-45 indicated a 21.0 inch asphalt pavement over 1.0 foot of medium dense clay loam, 5.0 feet of medium dense to dense sandy loam and dense sand. S-49 showed 10.0 inches of asphalt and 12.0 inches of concrete over dark brown and gray very stiff to hard clay loam fill. Both borings showed moisture contents generally decreasing with depth.

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Borings KED S-01 through S-04 were taken along Kedzie Avenue east and west of the I-57 structure. These borings were taken through the Kedzie Avenue pavement indicating a pavement structure consisting of 3.0 inches of asphalt over 10.0-13.0 inches of concrete underlain by stiff to hard brown and gray A-6 silty clay loam fill. Moisture contents ranged from 11- 25 per cent.

Specific soil conditions are shown on the soil boring logs contained in Appendix C.

PAVEMENT CONDITIONS

The pavement cores were performed along the driving lane of Interstate 57. The existing pavement consisted of approximately 4.5 inches of asphalt pavement overlying 9 inches of concrete pavement. Underlying these pavement sections, 3 manners of pavement support were encountered. Some core holes showed approximately 4 inches of asphalt base while others indicated approximately 4 inches of granular/screening subbase and the third encountered clay subgrade below the pavement.

Specific core conditions are shown on the core summary located in Appendix D.

WATER TABLE CONDITIONS

The majority of borings taken for this investigation showed dry conditions within the borehole both during and after the completion of drilling. When water was encountered during drilling, it was found at a depth of 6.0 to 9.0 feet (corresponding to an elevation range of approximately 604 to 610) with the exception of S-21 (Station 235+00). The water level was indicated below the pavement, and it is expected that this situation is a perched water condition sealed in by the hard clay encountered below the shoulder. We estimate the long term water table throughout the length of this improvement to be at an elevation of 606 or below according to the coloration change in the soils of brown and gray to gray. Fluctuations in the amount of water accumulated and in the hydrostatic water table can be anticipated depending on variations in precipitation and surface runoff.

ANALYSIS AND RECOMMENDATIONS

It is expected that the proposed pavement improvements will match or be similar to existing grade and alignment conditions along the existing I-57 corridor. For purposes of this analysis, we have assumed a typical roadway section to include a 4-inch bituminous asphalt pavement section, a 9-inch Portland Cement Concrete pavement section and a 12-inch aggregate subgrade and that existing grades along I-57 will remain nearly unchanged from current elevations. We recommend that the subgrade

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soils are suitable for support of the roadway with exception of the areas outlined on the following Table 2 – Remedial Treatment Recommendations.

TABLE 2 - REMEDIAL TREATMENT RECOMMENDATIONS

Station (Boring) Subgrade Unconfined Remedial Remedial Description Compressive Treatment Treatment (water content) Strength (tsf) Depth (inches)* Station 194+50 to Clay Loam 197+50 Southbound 1.25 12 PGES (w=24%) (S-4) Station 200+50 to Clay Loam 203+50 Southbound 1.5 12 PGES (w=21%) (S-6) Station 224+50 to Clay 227+50 Southbound 1.75 12 PGES (w=21%) (S-16) Station 227+50 to Clay 230+50 Southbound 1.25 12 PGES (w=18%) (S-18) Station 280+00 to Clay Loam 283+00 1.25 12 PGES (w=99%) (S-41) *verified undercuts in field

Undercutting should be performed in such a manner as to minimize disturbance to the undercut subgrade. Heavy equipment traffic directly on the undercut subgrade should be minimized. The actual need for the recommended treatment should be determined in the field at the time of construction based on guidelines presented in the Illinois Department of Transportation Geotechnical Manual under the direction of a licensed geotechnical engineer. Evaluation of soils in the field should be performed based on the guidelines presented in the IDOT Subgrade Stability Manual.

The clay, silty clay and silty clay loam soils which form the subgrade for the majority of the alignment have a Subgrade Support Rating (SSR) of Fair to Poor. It is recommended that an IBR of 2.0 be used. Also, we recommend a shrinkage factor of 15% for fill material volume calculations for cohesive or granular soils.

Prior to placing any fill at the site, it is recommended that the exposed surface at or near grade be proofrolled with the heaviest available equipment to determine if there are any localized deposits of soft or unsuitable materials. During the proofrolling procedure, the exposed surface is rolled with the heaviest piece of construction equipment available at the site, such as a heavily loaded tandem axle dump truck having a gross weight of not less than 25 tons. Any such deposits, as observed by deflection of the subgrade under the wheels of the proofrolling equipment, should be removed and replaced with an approved fill free of organic matter and debris. The silty clay loam soils are sensitive to moisture changes and some softening/disturbance of the exposed soils should be

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expected following periods of precipitation. Provisions should be included for some remediation of these soils during construction. The remediation may include lime stabilization or undercutting and placement of a stabilization stone such as IDOT gradation CA-1 or PGEs materials. However, due to time, monetary and/or space restraints, lime stabilization may not be desired.

Fill materials placed at the site should be consist of an inorganic approved material, compacted to a minimum 95% of AASHTO T-99 (ASTM D-698), standard proctor method. Moisture levels for fill material should be maintained within a maximum +/- 3% of the optimal moisture content or as directed by the engineer.

Traverse pavement underdrains should be installed at lowpoints in the road and in undercut areas to improve drainage. The drains should be 4-inch diameter, placed at a depth of 30 inches and installed in accordance with Check Sheet No. 19 of the Supplemental Specifications and Recurring Special Provisions adopted January 1, 2008.

Care should be taken in the design and construction of paved areas to provide rapid drainage of surface water and to develop surface drainage patterns that will divert water away from the pavement edges. When water is allowed to pond on or adjacent to the pavement, the subgrade may become saturated and accelerate pavement deterioration.

Construction of the proposed roadway improvements should be performed in accordance with the current Illinois Department of Transportation (IDOT) “Standard Specifications for Road and Bridge Construction. In particular, refer to Section 202, “Earth and Rock Excavation”, Section 205, “Embankment” and Section 301, “Subgrade Preparation”.

GENERAL QUALIFICATIONS

The analysis and recommendations presented in this report are based upon the data obtained from the soil borings performed at the indicated locations and from any other information discussed in this report. This report does not reflect any variations that may occur between borings or across the site. In addition, the soil samples cannot be relied on to accurately reflect the strata variations that usually exist between sampling locations. The nature and extent of such variations may not become evident until construction. If variations appear evident, it will be necessary to reevaluate the recommendations of the report. In addition, it is recommended that Geo Services Inc. be retained to perform construction observation and thereby provide a complete professional geotechnical engineering service through the observational method.

This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No other warranties, either expressed or implied, are intended or made. In the event that any changes in the nature, design or location of

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the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the conclusions of this report modified or verified in writing by the geotechnical engineer. Also note that Geo Services Inc. is not responsible for any claims, damages, or liability associated with any other party’s interpretation of this report’s subsurface data or reuse of the report’s subsurface data or engineering analyses without the express written authorization of Geo Services Inc.

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APPENDIX A

SITE LOCATION MAP

APPENDIX B

BORING LOCATION DIAGRAMS