Return to Seohae Grand Bridge (thing)

The [Seohae Grand Bridge] is the longest [bridge] in [South Korea].

It is a [cable-stayed] bridge crossing the [Asan Bay] 65 km south of [Seoul]. The [bridge] is 9.4 km long with a 870 m cable-stayed portion. The [main span] is 470 m long and is 62 m above the water.

The bridge accomodates six traffic lanes between [P'yongtaek] to the north and [Dangjin] to the south. It was designed by T.Y. Lin International, of [San Francisco]. The construction of bridge took seven years to complete. It was opened to [traffic] in November 2000.

The Seohae Grand Bridge is particularly remarkable for two reasons: the inclusion of [piston]-like [lock-up device]s and the design of the cable-staying [pylon]s.

The lock-up devices (LUDs) are fluid-filled chambered cylinders joined to the bridge girders. When the bridge changes shape, fluid flows through holes in the chamber division to compensate for the change. The size and shape of the holes and the [viscosity] of the fluid can be adjusted to make the piston react differently to different loads. These LUDs are "tuned" to allow slow movements such as those due to temperature change, [shrinkage] of building materials, or creep. Quicker and more abrupt forces, like those resulting from [seismic] activity or the high winds common to Asan Bay, "freeze" the LUDs and prevent movement.

The pylons of the bridge consist of two 180 m tall hollow [concrete] [tower]s. Each tower is "H" shaped, a variation from most cable-stayed bridges which use "A" or inverted "Y" shapes. The cables supporting the bridge deck are spread out through the vertical portion of the pylon. There are three horizontal [crossbeam]s, one near the bridge deck and two roughly one-third of the way from the top of the pylons. This double crossbeam style was chosen by the owner (the Korean Highway Corporation) for aesthetic reasons.

I recommend going to the ASCE web site below for excellent pictures of the bridge during construction and after completion.

Sources: [ASCE] 2002 calendar,