MnDOT's state bridge engineer Dan Dorgan says bridge inspectors were on the bridge this week as part of the state's review of its truss bridges. Dorgan says inspectors found rust and corrosion on the gusset plates.
"Not on the main spans but on the approach spans, and that was the reason we closed the bridge was because of that corrosion on those gussets, and the possible loss of capacity on those gussets," Dorgan said.
Gusset plates are the connectors that hold steel beams together. One of the bridge's gusset plates also showed signs of distortion. Dorgan says that leads to buckling, which could result in the bridge's collapse.
"The bridge was scheduled for replacement, but that schedule date was 2017, although that was being looked at with the new legislation as far as if it could be advanced," Dorgan said. "But I think the immediate need to restore traffic we'll be looking at repair. So that we can reopen as soon as possible."
Dorgan says the department is still trying to get a sense of the severity of damages to the bridge. He says he doesn't know when the bridge might reopen, or if any emergency traffic might be allowed to use the bridge while it's being repaired.
Minnesota owns the bridge, so while the state will coordinate with Wisconsin on a detour, Minnesota will be wholly responsible for repairs.
In the meantime, travellers will need to use the Wabasha or LaCrescent bridges to get across the Mississippi. Both bridges are 30 miles from Winona. Round-trip the detour is 60 miles.
Nearly 12,000 vehicles cross the bridge everyday.
Winona mayor Jerry Miller says this detour will have a significant economic impact on businesses and residents.
"Winona has a pretty strong industrial base, and we have a lot of people from Wisconsin that come over here to work everyday, and we also have people from Winona who go over to Wisconsin to Ashley or Gold-n-Plump in Arcadia to work. So you know that has a big effect," Miller said. "Plus we're a regional center, a lot of people come in to shop."
Miller is also concerned about the region's medical needs. Winona Health is the first responder for emergencies in Wisconsin's border counties. The nearest hospitals on that side of the river are in La Crosse, Wis., or Eau Claire, Wis.
Miller says MnDOT officials assured him that within the next three weeks they would have a handle on the status of the bridge, and a plan for emergency vehicles.
In the meantime, Miller is meeting with business owners to consider ways to minimize the impact of this closure. Busing is one option.
"Somebody brought up how about a ferry with people with boats bringing people across the river. We're also looking at available rental on this side. Say you work over here, you come over here and stay here for the week instead of having to drive all the way around," said Miller.
While Miller and others move ahead, many Winona residents are still stunned by the closure of their bridge. Winona City Council Member-at-Large Tim Breza says the news of the bridge's condition was shocking.
"And it's deplorable that the maintenance has not been kept up on the bridges in the state of Minnesota and our bridge in Winona," said Breza.
This is the second bridge to be closed as a result of concerns over gusset plates. The DeSoto bridge in St. Cloud is closed, and is scheduled to be replaced.
All of this concern stems from the collapse of the I-35W bridge last year. That bridge had an undersized gusset plate that made it prone to collapse.
MnDOT officials say inspectors will conclude their investigation of truss bridges in Minnesota by the end of June.