Overtopping Formulas for Caisson Breakwaters with Nonbreaking 3D Waves

Abstract

From the analysis of an extensive series of two-dimensional and three-dimensional hydraulic model tests on the overtopping response of various types of caisson breakwaters, general design formulas and graphs have been derived. Exponential relationships relate the mean discharge and the percentage of overtopping waves with the relative freeboard. The parametric influence of geometrical changes and of wave obliquity and multidirectionality is described by reduction factors referred to the case of simple vertical structure under long-crested head-on wave attack. Comparisons are made with the three-dimensional overtopping response of sloping structures. Overtopping volumes per wave have also been measured and their distribution fitted with a universal probability function. Even the effects of overtopping waves on pedestrians behind the crownwall were statistically evaluated to allow an upgrading of the existing criteria for the admissible rates over breakwaters.