Abstract
In breakwaters covered with wave-dissipating blocks, outer walls of the caisson may show local failure in repeated collision of the blocks. Local failure induces drainage of the filling in the caisson so that the self-weight of the caisson would be reduced. This failure of the outer wall decreases stability of the caisson against sliding and harbor calmness. The design and verification method of the caisson and the preventive measures against such accidental impact loads are necessary to be developed while they have not been established so far. When the preventive measures are implemented, it is important that the life-cycle cost (LCC) would be considered. This paper investigated the advantageous conditions of the preventive measures from the viewpoint of LCC reduction considering the ratio of failed caisson to total ones, by comparing the cost for the preventive measures and the cost for post-failure repair.
