MOLINE, Ill. — While demolition on the old I-74 Bridge continues, two lead engineers gave a presentation at Western Illinois University's Quad Cities campus on how their teams are overcoming challenges.
"The biggest challenge is anytime you're working on a river, whether high water, low water, there are a lot of different things," I-74 Quad Cities corridor manager George Ryan said.
A key concern of dismantling the bridge was the impact on the Mississippi River and the surrounding environment.
"In this instance, there were a lot of endangered mussels on the Illinois side between the lateral dam and the Illinois bank, and those were certainly a concern," Ryan said.
He explained that careful planning was required along with cooperation among several departments.
"Illinois EPA, Iowa DNR, fish and wildlife, and the Corps and the Coast Guard — there was a lot of coordination with a lot of regulatory agencies," Ryan said. "They take a real hard look at plans to do these things, just to make sure that we're protecting the environment."
Experts determined the best approach was dismantling the bridge and carefully excavating its concrete, as opposed to imploding it.
"There's a lot of engineering that goes into those processes of dismantling the bridge and deciding how big of segments we can take at a time, weight calculations and sizing equipment crane-wise to be able to lower the segments," Helm Group project leader Tom Schebler said.
He explained that this approach doesn't just save money and protect the environment.
"We're in an active waterway here," Schebler added, "so we can't block commercial traffic for long periods of time."
The demolition contract costs around $23 million and crews are hoping to finish the work in early 2024.
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