Abstract
The understanding of interactions between tsunami and structure is very important to consider tsunami countermeasures, though the interaction includes complex phenomena. For example, two-phase flow can be found when the tsunami hits a bridge structure with entrapping air beneath it. The air sometimes affects forces acting on the bridge, and the effect of entrapped air has to be taken into account to investigate the tsunami forces. This study is intended to investigate the tsunami forces acting on the bridge with using two-phase flow model. Three bridge models were tested in this study, where the slab bridge without girders beneath it, the slab with two girders, and the slab with three girders. The simulation results were compared with the results obtained from one-phase flow simulation, and also verified with experimental ones. This study revealed that, in the investigation of tsunami forces acting on the slab bridge without girder, the results of both one-phase simulation and two-phase one agree well with experimental results. In the simulation on the slab bridge with girders, the results from two-phase simulation correlate better with experimental results in comparison with the results from one-phase simulation. Furthermore, the entrapped air between girders highly affects the characteristic of uplift force.
