Experimental simulation of tsunami surge and its interaction with coastal structure

Abstract

Following the tsunamis occurred in Japan (2011) and Indian Ocean (2004), investigating interaction between coastal structures and tsunamis became necessary. Although several attempts have been made to estimate the tsunami forces acting on the coastal structures, there still remain inconsistencies among the published design guidelines. This research includes an experimental study to investigate the interaction between a tsunami surge and a coastal structure. The tsunami surge was generated using a novel dam-break system, capable of generating higher tsunami surges than the previous simulations. The relations between surge velocity, surge depth, and surge-induced pressure on the structure were presented. In the surge-induced pressure–time histories, there were three identified force components, namely, run-up, impulsive and quasi-steady hydrodynamics. Furthermore, this research presents a comparison made between the experimental results and existing tsunami guidelines. The ratio of impulsive force to hydrodynamic force was found around 2.4 for each tsunami surge. The hydrodynamic forces were found to be higher with respect to those determined using the ‘Federal Emergency Management Agency’ FEMA P646 guidelines, whereas they were approximately in agreement with those obtained by FEMA 55. Moreover, the results showed that the ‘Structural Design Method of Building for Tsunami Resistance’ overestimates the impulsive force.