Abstract
Flap-gate tsunami breakwater, which lies down on the seabed and rises up with its buoyancy in occurrence of tsunamis has been developing. Flap-gate usually has buoyancy and mooring systems keep it lying down so as to shorten a rising time after earthquakes. Dynamic mooring forces of the gate have to be estimated to design these systems since they have to support wave pressure acting on the lying gate in addition to buoyancy of the gate. This study evaluated these forces through model experiments, field experiments, and calculation using equations of motions of the gate. As a result, it was confirmed that the mooring system that allows slight motions of the gate reduced mooring forces, and a method to estimate these forces was obtained. We can realize reliable coastal structures against tsunamis by using this result.
