A new load surface based approach to reliability analysis of caisson type breakwater is proposed. Uncertainties of horizontal and vertical wave load acting on breakwater are considered by using the so called load surfaces which can be estimated as a function of wave height, water level, and etc. Then, gradient based reliability analysis such as First Order Reliability Method(FORM) can be applied to find out probability of failure under wave action. Therefore, reliability analysis of breakwaters with uncertainties both in wave height and water level can be possible. In addition, uncertainty in wave breaking can be taken into account by using wave height ratio which relates significant wave height with maximum one. In numerical examples, proposed approach was applied to reliability analysis of caisson breakwater under wave attack which may undergo partial or full wave breaking. |