Reliability based design method for coastal structures in shallow seas

Abstract

Reliability based approach is considered an important component in risk assessment of coastal related projects. Such an approach is mandatory during the initial planning stage of coastal projects thereby providing information on the failure of structures. The damage to a structure can result from various environmental forcing and moreover depends on where the structure is located. As a case study, an existing coastal jetty at Andaman Sea was chosen which was subjected to extreme waves during a cyclonic episode prevalent in the Bay of Bengal. Wave information encompassing this coastal jetty was investigated using a very high resolution state-of-art SWAN wave model run in non-stationary mode. Wave forces are estimated using Sainflou and Miche-Rundgren methods along structural length of this jetty. In addition, wave run-up and wave overtopping were estimated using SWAN model generated wave information. A Level-II reliability analysis was carried out for this coastal jetty, subjected to various levels of assumed uncertainty. Further, lifetime and encounter probability under various degrees of uncertainty in load and resistance for this coastal jetty has been investigated and analyzed. Based on analysis, it is believed the significance of this work can lead vital information for assessment studies in integrated coastal zone management.