Modified Goda formula to simulate sliding of composite caisson breakwater

Caisson breakwaters can continue to maintain their function if a limited amount of sliding or tilting occurs. Although this has been the focus of much research during the last years, little attention has been paid to the design of composite caisson breakwaters (i.e. caissons protected with armour layers). The present paper outlines laboratory experiments that were carried out to propose a modification of the Goda formula (1974) that takes into account the increased pressures that can be exerted by waves due incomplete armour layers at the seaside face of the caisson. The effect that this modification can have on the expected deformations in the rubble mound after one storm are also evaluated by means of a Monte Carlo Simulation, showing how incomplete armour layers will result in much greater expected vertical movements in the caisson.