Author(s): Takaaki Abe; Jungo Funaki; Yasuhiro Yoshikawa; Toshihito Toyabe
Keywords: No Keywords
Abstract: This paper investigates the characteristics of the wave force exerted on bridge girders in the case of a severe river tsunami with ice floes. In cold snowy regions, tsunamis in rivers can cause river ice floes to be transported and, consequently, to strike river structures. This study aims to clarify the characteristics of river-tsunami wave force on bridges by a series of hydraulic experiments and, on that basis, to develop a practical tool for simulating interactions between tsunamis, river ice floes and river structures. The numerical method we use is based on the Moving Particle Semi-implicit (MPS) method, which is capable of simulating a wide variety of hydraulic problems, such as solid-liquid two-phase flows and the blocking of river structures by drifts. The experimental and simulated results show that ice floe drifts can cause the water level downstream to increase and can cause wave force to act on bridges, which can result in tsunami overflow or, in the worst case, a bridge collapse. In addition, the flow field obtained from the numerical model clearly shows that these rises in wave force are induced by continuous dynamic water pressure. This work highlights the potential risks of ice floes and quantifies the forces exerted on structures by river tsunamis with ice drifts.