St. Croix Crossing is an extradosed bridge, a hybrid between a girder bridge and a cable-stayed bridge, chosen because its signature qualities complement the natural attributes of the river valley. In this structure, the weight of the bridge and its users is supported by the piers and the external cables. Its foundations originate in sandstone up to 100 feet below the river bottom. The main river crossing has four equal spans of 600 feet, and the driving surface is about 110-150 feet above the river, shortest near the Minnesota shore and tallest near the Wisconsin shore. Each pier tower rises about 65 feet above the bridge deck. The bridge deck was constructed using about 1,000 individual segments, each up to 18 feet tall and 48 feet wide, placed one at a time from each pier until they met at mid-span between the towers. The bridge opened to traffic in 2017.

Photo: Fitzie Heimdahl

Houlton, Wisconsin · USA