Ohio River Span a Variation on Conventional Tied Arch

摘要

When completed, the Blennerhas-sett Island Bridge will be the longest in West Virginia, but the structure is notable for more than its length. For one thing, it will fill the last remaining gap in Corridor D, a 300 mi (483 km) long highway project that was originally authorized by Congress 40 years ago as part of the Appalachian Development Highway System (ADHS). With a construction cost of approximately $120 million, the bridge project represents the largest highway contract in state history. As it passes over the Ohio River just west of Parkersburg, West Virginia, the 4,008 ft (1,222 m) long bridge crosses a secondary channel, then the western end of Blennerhassett Island, and finally the main navigational channel. The approach spans range in length from 140 ft (43 m) to 400 ft (122 m). The bridge's 880 ft (268 m) long, 100 ft (30 m) wide main span takes the tried-and-true form of a tied arch, but the cables descending from the arch ribs to support the deck are not vertical. Instead, they are inclined in two directions, crossing each other to form a network in the plane of each rib.