The $18.5 million replacement and rehabilitation of the I-90/94 Interchange at Ohio Street in Chicago, Illinois, featured innovative design services that reduced construction and maintenance costs, and incorporated methods to avoid major lane and ramp restrictions and minimize negative impact on the 300,000+ daily users.
The Illinois Department of Transportation (IDOT) selected Collins to provide design services for the reconstruction and realignment of the ramp pavement and structures carrying westbound Ontario Street to both directions of I-90/94 (Kennedy Expressway).
Working with IDOT, Collins developed the concept that replaced the existing seven-span structure with two separate smaller structures—a three-span and a single-span—separated by mechanically stabilized earth (MSE) retaining walls. This provided a simplified design and produced cost savings in terms of less steel and less overall structure to maintain in the future.
The demolition of the existing curved concrete box beam ramp/bridge structure presented a significant challenge. The existing one-piece structure had to be removed all at once and required a large work zone. Collins developed a bridge demolition sequence and traffic staging scheme that called for a portion of the interstate to be shut down over the course of three weekends in June 2014, starting at 10:00 p.m. each Friday and ending by 5:00 a.m. the following Monday.
Through intensive project coordination and planning, the demolition was completed in two weekends instead of three. Additionally, the interstate was opened to traffic each weekend by Sunday morning, one full day ahead of schedule, significantly reducing the construction’s impact on the motoring public.
The new structures and realigned ramp improve traffic safety, capacity, and mobility thereby reducing noise and enhancing air quality. The new ramps increased merge lengths and sight lines providing an improved overall user experience.