Stanley Consultants provided engineering services for the extensive reconstruction of the Tri-State Tollway between Roosevelt Road and St. Charles Road in Illinois. This transformative project involved the complete redesign and reconstruction of the I-290/I-88 Interchange at I-294 to significantly improve operations and safety in this highly congested interchange. The work encompassed two miles of roadway with up to twelve mainline lanes, multiple collector-distributor roads, ramps and an array of complex infrastructure components. The project required the design of 30 intricate bridge structures, 20 retaining walls, over a mile and a half of noise abatement walls, as well as comprehensive drainage systems, lighting, intelligent transportation systems (ITS), tolling facilities and utility relocations.
The reconstruction, delivered through more than six reconstruction contracts totaling over $700 million, demanded innovative engineering solutions. These solutions addressed the challenges of complex maintenance of traffic and construction staging to improve the safety of both the 300,000 vehicles that travel this portion of the Tri-State daily, as well as the contractors and engineers working to deliver the improvement. Stanley Consultants led the design efforts for the southbound roadway, seven ramps and numerous bridges, including mainline, ramp and crossroad bridges. Among these structures were the tri-level, two-span and three-span bridges over I-88 and direct-connect ramps, which incorporated curved designs, steel plate girders and post-tensioned straddle bents for enhanced performance and durability. The project also included retaining walls and noise abatement walls designed to support the expansive infrastructure.
In addition to design responsibilities, Stanley Consultants played a critical role in conducting constructability workshops and reviews, helping to develop practical, effective solutions for the project’s unique challenges. The collaborative approach and dedication to delivering high-quality designs contributed to the success of this significant infrastructure project, which improves traffic flow and connectivity for one of the region’s busiest corridors.