A Grand New bridge

Approximately 65 km south of Seoul, rising above the Asan Bay, the Seohae Grand Bridge now stands as the longest bridge in South Korea. The 9.4 km long cable-stayed bridge, which runs from Pyongtaek on the north side of the bay to Dangjin on the south, took seven years to build. The bridge incorporates piston-like lock-up devices (LUDs) that allow movement under temperature changes, creep, and shrinkage but resist such dynamic loads as aerodynamic motions from high winds and earthquakes. These devices are of cardinal importance, because a primary design challenge for the Seohae Bridge is its location in a high-wind area. The main bridge, which is 990 m long, consists of an 870 m long cable-stayed structure and two 60 m long end spans of simply supported composite girders. The cable-stayed portion has three spans—a 470 m center span and two 200 m side spans. The center span provides a 62 m high navigation channel above the high sea level of 4.7 m.