Removing one interchange bridge and replacing it with another is the kind of job that can give a contractor more than a few headaches. But when the job is in the heart of Chicago on an expressway that sees an average of 260,000 vehicles daily, that headache can quickly morph into a major nightmare.
That was the task contractors faced this June as they brought down the Ontario Street bridge exit onto I-90/94, also known as the Kennedy Expressway, as part of the Ohio Street interchange project. The project was slated for three weekends when they would close parts of the expressway to traffic and create detours around the work.
The potential for any number of problems was great, but instead the work went off with barely a hitch and with the rare outcome of not only finishing on time — but early.
The bridge was originally constructed in 1959. It was a three-unit, eight span concrete structure cast in place, said Jae Miller, spokesperson of the Illinois Department of Transportation.
“It needed to be repaired and they felt that just rebuilding it would be more cost effective in the long run rather than repairing it here and there,” Miller said. “They’ve been working on it for years. Anything of this nature takes funding, so there was much legwork to get the project completed. The last couple of months, we worked really closely with city of Chicago. Because it was over a major expressway and that involved closing it down. We had to really work closely to make it move smoothly. The city was really concerned what it might do to the city and the traffic flow. So many events happening. We had to be really careful to be sure we had the necessary equipment.”
The $16.5 million project originally called for backhoes to be on the site, but at the height of the job, the contractor more than doubled that, bringing 10 backhoes to the scene.
They closed off the expressway, sanded the road beneath it to protect the pavement from crumbling concrete and the equipment operators went to work.
“You’re talking a lot of folks on the road,” Miller said. “They created a two lane diversion so that in theory if you were traveling along the Kennedy you could still get through. The challenge was to make sure the public was well aware of the alternate routes. There was a huge media effort. The local media and media in surrounding states were aware months in advance making sure people were off the roadways. We were able to get the trucks in quicker because less vehicles on the road. Those backhoes just pinched away at the bridge. They kept chipping away, chipping away and it came down.”
The new bridge is already in place and features a three-span, steel girder structure over I-90/94 and a single span, steel girder structure over the eastbound I-90/94 to eastbound Ohio Street exit ramp. The project also involved the extension and deck beam replacement of the westbound Ontario Street to westbound I-90/94 ramp tunnel structure. Other minor work included the construction of a retaining wall along the westbound Ontario Street to the eastbound I-90/94 ramp, drainage improvements and new roadway lighting under the tunnel structure.
In the course of the project, contractors worked with backhoes with breakers as well as backhoes with processors to separate rebar, two front end loaders, one bobcat, two sweepers, 16 dump trucks and two steel haulers. A crew of 124 worked in two shifts of 62 each, along with four Illinois State Police on continuous service and staff from the IDOT communications center and Office of Emergency Management.
In the end, despite the inauspicious starting date and full moon of Friday the 13th, something few failed to notice, the project finished a full week early, an unexpected bonus that Miller credits to the contractor bringing in the extra equipment at the start.
“It was smooth sailing both weekends,” Miller said. “We got so much completed that first weekend, were able to shave down that one weekend.”
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