Comparative Study of Design Methods for Sliding of Perforated-wall Caisson Breakwater

摘要

The conventional performance-based design method for the solid-wall caisson breakwater has been extended and applied to the perforated-wall caisson.The mathematical model to calculate the sliding distance of a perforated-wall caisson is verified against hydraulic experimental data.The developed performance-based design method is then compared with the conventional deterministic method in different water depths.Both the expected sliding distance and the exceedance percentage of total sliding distance during the structure lifetime decrease with decreasing water depth outside the surf zone,but they increase with decreasing water depth inside the surf zone.The performance-based design method is either more economical or less economical than the deterministic method depending on which design criterion is used.If the criterion for the ultimate limit state is used,the former method is less economical than the latter outside the surf zone,whereas the two methods are equally economical inside the surf zone.However,if the breakwater is designed to satisfy the criterion for the repairable limit state,the former method is more economical than the latter in all water depths.