Abstract
In this study, the optimal threshold for preventive maintenance to minimize the maintenance cost is determined for the wave dissipating blocks covering caisson breakwater by using a theoretical model. It is necessary to determine the probability distribution of the damage of block layer caused by a storm in this model, and the Weibull distribution is used on the basis of result of Monte Carlo method utilizing a stability formula for wave dissipating block. Secondly, it is confirmed that the stability of breakwater to the horizontal wave force is maintained by the theoretical optimal threshold for preventive maintenance based on comparison with the experimental results. Furthermore the theoretical optimal threshold agrees with the simulated result that is obtained from Monte Carlo method considering the variation of repairing cost and the validity of the theoretical model is verified.
