The Highway 243 bridge over the St. Croix River, which connects the Wisconsin town of Osceola with Franconia Township in Minnesota, will be closed from Sept. 12 to 28 for repairs. It will also be closed for one unspecified day in the middle of October.

The work will seek to repair and resurface the bridge’s deck and erosion on a neighboring hill. The bridge was closed for a weekend in July for emergency repairs after a two-foot hole appeared in the bridge deck.

Traffic will be detoured to the Highway 8 bridge in Taylors Falls, about seven miles upriver.

The Saint Croix National Scenic Riverway’s Osceola Landing will remain open and accessible from the Minnesota side of the bridge during construction.

The Highway 243 bridge was built in 1953 and rebuilt in 1980. Highway and bridge expert John Weeks III writes on his excellent website that the bridge “gained a bit of fame after the I-35W bridge collapse in 2007” because its deck truss design is obsolete.

“The reasons include being fracture critical (i.e., non-redundant, which means that any one piece breaking can result in the entire bridge failing), they are very hard to inspect (the structure is under the road rather than above the road), they are easily damaged by road salt (which can leak though cracks in the deck and cause the steel to rust), and truss bridges are far more costly to maintain,” Weeks explains.

The bridge is inspected every other year, but it is not considered deficient, and no replacement is planned in the near future.

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