Vibrating-rocking motion of caisson breakwater under breaking wave impact

The possible motions of a caisson breakwater under dynamic load excitation include vibrating, vibrating-sliding and vibrating- rocking motions. The mo dels of vibrating motion and vibrating-sliding motion have been proposed in an early paper. In this paper, a model of vibrating- rocking motion of cai sson breakwaters under breaking wave impact is presented, which can be used to simulate the histories of vibrating-rocking motion of caisson breakwate rs. The effect of rocking motion on the displacement, rotation, sliding for ce and overturning moment of breakwaters is investigated, In case the overt urning moment exceeds the stability moment of a caisson, the caisson may on ly rock. The caisson overturns only in case the rocking angle exceeds the c ritical angle, It is shown that the sliding force and overturning moment of breakwaters can be reduced effectively due to the rocking motion, It is pr oposed that some rocking motion should be allowed in breakwater design.