The bridge will remain closed as a safety precaution until further investigation can be completed and repairs can be made. The Plymouth Avenue Bridge is a post-tensioned box girder bridge, a type of bridge design that includes multiple redundancies in the structure, and which is not a fracture-critical design.
The City of Minneapolis inspects all of its bridges annually. During routine maintenance and repair work completed, workers found signs of corrosion in the bridge tendons, which are tensioned cables running through the concrete structure of the bridge. These cables are not visible from the exterior of the bridge. Additional investigation led engineers to conduct an examination of the interior of the bridge structure to determine the extent of the corrosion. That examination was done this morning, and due to the level of corrosion, Public Works officials decided that as a safety measure, the bridge should be closed while further evaluation is being done.
The Plymouth Avenue Bridge connects north and northeast Minneapolis, and is located six blocks south of the Broadway Avenue Bridge, which is the recommended detour. Transportation officials do not believe the closure will significantly slow traffic because the detour route is relatively short.