By Bruce Karnick

As drivers have experienced the last week, MnDoT crews have been performing maintenance on the Highway 61 bridge over the Mississippi River. The bridge utilizes an automatic de-icing system. While this is great for winter driving conditions, it does cause additional maintenance issues. One such issue is the coating on the painted surfaces requires a gel coating. When the gel coating cracks, the paint underneath can be affected by the elements as well as the de-icing agent. Part of the crew doing the maintenance is sealing any cracks in the paint and gel coating on all the vertical surfaces.

Another, more important repair is taking place in the northern expansion joint. The expansion joint allows the bridge to expand and contract as needed based on the current temperature. These joints are sealed with a specialized rubber piece. The seal prevents the de-icing agent from leaking down into the support structure of the bridge causing premature corrosion. The maintenance supervisor for MnDoT, Tony, ran through the process with The Journal on September 30th. “We’ve been down a few times over the last year to try to patch it, but the patches haven’t held as long as we would have liked.” He said. Think of patching a really big, thick bike tire. “I think the problem is road debris. Something hard and sharp finds its way into the seal and then a vehicle drives over it, driving it through like a knife.” Tony explained. That has led to a full-on replacement of the entire seal. Drivers can expect lane closures through at least October 9th, possibly longer. “It all depends on the weather. If the weather cooperates, we should be done by Friday.”

They will have multiple crews working on the bridge deck and the rails. Please slow down and drive safely around the workers. Additional details and updates to the project can be found at 511mn.org

Members of the MnDoT maintenance team work to repair the seal on the expansion joint at the north end of the Hwy. 61 Bridge.