Abstract
It is reported that protective barriers such as coastal dikes and roughness of ground surface may reduce tsunami wave force acting on land structures. The purpose of the present study is to develop an estimating method of reducing effect of tsunami wave force through hydraulic model tests and analytical model studies. The hydraulic model test applying Froude similarity's law with the scale of 1 to 100 was conducted in order to clarify the characteristics of wave force reduction by protective barriers. It was found out that tsunami wave force is reduced according to the height of costal dike, roughness of ground surface and the distance from the coast line. It was confirmed that drug coefficient changes according to the Froude number. A simple analytical method to compute the change of Froude number considering effects of discharge reduction and energy consumption was developed. The computed results are in good agreement with the experiment data.
