Practical Methods of Estimating Tilting Failure of Caisson Breakwaters Using a Monte-Carlo Simulation

Abstract

The authors propose a new method to estimate the tilting failure of caisson breakwaters, using a Monte-Carlo simulation that can quantitatively and stochastically estimate failure probability. An index, referred to as "Expected Frequency Exceeding of a Critical Load (EFEC)" that expresses the potential tilting failure probability of caisson breakwaters is proposed and adopted in this model. Application of the model to 40 breakwaters in Japan reveals that the threshold value of EFEC that specifies whether a caisson breakwater is safe or unsafe could lie in the range from 0.02 to 0.04. The authors also found that unstable caisson geometry, showing a large value in the aspect ratio of the caisson, can provide additional indication of when tilting failure is likely to occur. It is expected that the present method can provide a practical way for engineers to judge the possibility of tilting failure in caisson breakwaters.

Probabilistic Risk Evaluation for Overall Stability of Composite Caisson Breakwaters in Korea

“…In Europe, Level 1 and Level 2 probabilistic analyses have been developed, while Level 3 has been successfully carried out in Japan [19]. Notably, the Level 1 and Level 2 reliability design methods are based on the mean value first-order second-moment (MVFOSM), and first-order reliability method (FORM), respectively [11,12], whereas the Level 3 reliability design method is related to the estimation of the caisson sliding distance [18,19,21,22] or the expectation of damages occurring in the armor blocks of horizontal composite BRWs [23]. In this study, the safety of nine typical Korean vertical BRWs is estimated using different reliability analysis methods, MVFOSM, FORM, and the Monte Carlo Simulation (MCS).…”