TERRA was part of a team retained by the Illinois Tollway to reconfigure the I-94 / Grand Avenue Interchange near Gurnee, Illinois. TERRA was responsible for the surveying, landscaping, erosion control plans, Storm Water Pollution Protection Plan (SWPPP) and design of a 10-foot-high, 1,300-foot-long soldier pile retaining wall to accommodate an additional auxiliary exit ramp in the south east quadrant of the interchange.
The retaining wall was designed to incorporate drainage structures in front of the wall and drainage laterals through the foundation. Drainage behind the wall was accomplished through a concrete swale formed at the top, and immediately behind, the wall to transport water to a drainage structure located at the end of the structure.
TERRA also generated landscape and erosion control plans as a part of the design.