Corrosion-Inhibiting Powder Protects Bridge Cables During Construction
The St. Croix Crossing, dedicated August 2, 2017, is a significant new structure connecting Oak Park Heights, Minnesota, with St. Joseph, Wisconsin. The new bridge is expected to promote regional economic development and reduce congestion by replacing the historic but aging Stillwater Lift Bridge (destined for pedestrian traffic) with an engineering masterpiece. The new St. Croix Crossing is designed to carry tens of thousands of vehicles in uninhibited travel across the St. Croix National Scenic Riverway every day.
Because of its unique environment, the approximately one mile long crossing was specially designed as an extra dosed bridge (combination box girder and cable stay bridge) to minimize the environmental and visual impact of the structure on the St. Croix River Valley. As one of only two of its kind in the United States, it is a model of engineering and design ingenuity. Cable stays support the bridge at five pier locations in the river, while approximately 1,000 pre-cast boxlike segments are connected by post-tensioning (PT) cables that are tensioned and grouted in place. PT was also used in the crossbeams connecting upstream and downstream towers at each of the five pier sites.