I-90 Jane Addams Memorial Tollway Reconstruction

Milepost 73.3 (Oakton Street) to Milepost 78.8 (Kennedy Expressway), ISTHA Contract I-11-4015

Project Description

The overall project consisted of reconstruction and widening of existing mainline and ramp pavements, reconstruction and/or rehabilitation and widening of existing bridges, construction of proposed earth retention walls, construction of new sign structures, and construction of new drainage structures and modification of the existing drainage system. Subsurface exploration, geotechnical analysis, and reporting were required for the planned roadway, bridge, retaining walls, culvert extensions, and sign structures.


We developed an exploration program in accordance with the Tollway requirements and guidelines.  All work was completed in accordance with the Tollway and IDOT Geotechnical Manuals, the IDOT Standard Specifications for Road and Bridge Construction, and the latest AASHTO LRFD Bridge Specifications. Exploration for this project included:

  • Advanced a total of 205 borings to a depth of 10 feet each for approximately 5.5 miles of roadway.  GSG completed laboratory testing program and engineering analysis and prepared Roadway Geotechnical Report (RGR).
  • Completed subsurface exploration for 19 bridge structures, completed engineering analysis and foundation recommendation, and prepared Structural Geotechncial Report (SGR) for all structures.
  • Completed subsurface exploration fo 24 retaining walls, with a total length of approximately 15,000 linear feet, including 365 borings to depths up to 80 feet below grade. Prepared SGR for each structure, including analysis of the slope stabilty of the proposed retaining walls, foundation recommendations, and anticipated construction considerations.
  • Completed subsurface exploration  for 22 new sign structures, includinga total of 63 borings to depths up to 90 feet. GSG prepared SGR, including recommendations for the proposed foundations as well as overturning analysis and construction considerations.

Completed subsurface exploration for 4 culverts including a total of 14 borings to a depth of up to 55 feet and prepared SGRs including recommendations for design and construction.

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