Effect of Short-Crestedness and Obliquity on Non-Breaking and Breaking Wave Forces Applied to Vertical Caisson Breakwaters

This paper addresses wave forces applied to vertical caisson breakwaters. Design diagrams are proposed to evaluate the reduction of the wave force induced by breaking and non-breaking short-crested oblique waves with increasing horizontal length of the caisson units. Results are derived by testing a model of a typical Italian vertical breakwater with moderately high rubble mound in the CRF-LSF (Wallingford, UK) wave basin equipped with a multidirectional wave generator. Seven adjacent caisson modules were instrumented with synchronized force transducers. Non-breaking and breaking wave loads are distinguished on the basis of the frequency content. The reduction factor of the load per unit span is derived by the measured spatial correlation, following the argument developed by G.I. Taylor for random movements.