It's opening: A milestone for the Tri-State, a wider Mile Long Bridge for drivers
Spanning two railroads and three waterways, it's not surprising the new southbound Mile Long Bridge on the Tri-State took 34,000 cubic yards of concrete, 52 steel beams and uncounted cups of coffee to build.
The towering structure -- expected to last 100 years -- replaces the existing southbound bridge with a transition between the two starting Tuesday evening and ending by early afternoon Wednesday.
It's not apparent when you're driving on it, but the Mile Long Bridge is actually two side-by-side structures dating back to 1958.
Construction of a new northbound bridge began in 2019 and finished in 2020. Work on its southbound twin started in 2021.
The 4,800-foot-long bridges are five lanes wide compared to the original four. Inside shoulder lanes will be used for emergency vehicles and to accommodate vehicles when necessary, as well as for transit, such as express buses.
"The Mile Long Bridge project was a tremendously complex undertaking," Acting Chief Engineer Manar Nashif said. "The challenges included planning and constructing a bridge while maintaining traffic volume of 150,000 per day."
The entire project cost $500 million and is part of a massive $4 billion widening of the Central Tri-State (Interstate 294) between Rosemont and Oak Lawn.
Completion of the southbound Mile Long Bridge is a significant milestone in the Central Tri-State program, tollway Executive Director Cassaundra Rouse said.
"Replacing bridges, including the Mile Long Bridge structures, throughout the 22-mile corridor will allow us to deliver the new and improved roadway on schedule to our customers," she said in a statement.
The project was an engineering Rubik's Cube -- spanning the Canadian National and BNSF railways, a UPS distribution center, 75th Street, the Des Plaines River, the Illinois and Michigan Canal, and the Chicago Sanitary and Ship Canal.
Adding to the complexities are underground gas lines and a jet fuel line to O'Hare International Airport.
It's like "we're spanning a whole city," officials described the challenge in 2019.
"The bridge consists of large concrete and steel beams that support the deck of the bridge," Manar noted. "The beams required special transport, which included police escort due to their sheer size. Also, the placement of the beams was performed through use of an innovative gantry system that was positioned on top of the bridge."
Removal of the original southbound bridge will be completed in 2023.