Long-Term Modelling of Wave Run-Up and Overtopping during Sea Storms

This paper is concerned with the determination of the return period of a sea storm in which response (run-up or overtopping) of a coastal structure exceeds a fixed threshold. The method is based on long-term statistical analysis of the sea states interacting with the structure and on practical formulas proposed in the past decades for determining response of coastal structures. The proposed methodology accounts for nonstationarity of sea states in time domain by the equivalent triangular storm model, which allows us to determine closed-form solutions of the return period of a storm where maximum significant wave height is larger than a fixed threshold. In this paper the analytical solution is supplemented by a practical application pertaining calculation of the response of a coastal structure. A rubble-mound breakwater is supposed to be placed at a known water depth, and then, starting from offshore significant wave height data, the return period of a given response threshold is calculated.