(Radio Iowa) – The bridge over the Mississippi River between Lansing, Iowa and DeSoto, Wisconsin is again closed to traffic for at least a week. Clayton Burke, an engineer with the Iowa Department of Transportation, says they had to close the structure on Saturday night.

“Our monitoring system was identifying that the bridge had moved beyond our safety thresholds and the engineering firm performing the monitoring was recommending that we close the bridge,” Burke says. “Now we’re trying to figure out what happened and analyze the bridge to see if it’s still safe to reopen.”

Burke says they have not determined a reason for the apparent movement of the bridge, but they’re focusing on two possibilities. “We did have construction work going on adjacent to the bridge on Saturday that involved driving some pipe pile with a vibratory hammer, which previously we had tested and found that it did not affect the bridge,” Burke says. “We’re also looking into if there were any un-permitted or any oversized loads that were crossing the bridge.”

Mississippi River bridge at Lansing. (File photo, Iowa DOT)

All of the instrumentation involved is being double-checked. “If the sensors are accurate, then it’s going to come down to, we have to do a detailed and thorough analysis to make sure the bridge is still safe to open,” Burke says, “and that could maybe take a week or so.” A new bridge is being built beside the current bridge and construction work on that new structure is also being halted.

“We have to make sure that everybody’s safe, the public and the contractor,” Burke says. “While we don’t know the condition of the existing bridge, we don’t feel that it’s safe for the contractor to be working next to it until we evaluate the structure and deem that it is safe.”

The bridge was closed for a similar reason in February and March of 2024. The nearest bridges for vehicle traffic to cross the Mississippi River are at La Crescent, Minnesota/Lacrosse, Wisconsin, or Marquette, Iowa/Prairie du Chien, Wisconsin.