Numerical Simulation of Washed Process of Girder Bridge by Tsunami Run-up

The earthquake off the west coast of Northern Sumatra and the resultant giant tsunami in the Indian Ocean in 2004 caused enormous damages in coutries around the Indian Ocean. As one of them, it was reported that a girder bridge crossing a river was washed away. In this study, numerical simulations by the particle method, which is suitable to treat a moving object and track a water surface, were carried out to examine the relation of a tsunami velocity and motion of a girder bridge. The calculated results showed good agreement with ones in a previous hydraulic experiment. In addition, in the case of a tsunami with drift woods and a bridge with handrail, the washed process of a girder bridge was simulated.