Updating Failure Probability of Jacket Platform in Malaysian Waters

Reliability analytical studies the uncertainties in load, geometry, material properties, operational environment and other uncertainties. Usually the system is performed under two conditions, specified service condition and specified period of time. Structure lifetime has its own limit state or constraint. When the design meets the requirement imposed on the structural behavior met within the range according to the code of standard, it is classified as satisfied and safe. In this study, the paper describes a method to determine the failure probability and evaluate the failure probability when the structure has experienced a wave loading by men of updating the probability using Bayesian method and truncation method of updating. This paper also brings about the variation of experienced wave height of RSR 1.0 and 1.5 at different direction on the failure probability of the selected jacket platform. This study found out that, the updated failure of probability shows a significant decrement when the experienced wave loading is increasing. The design probability of failure is 3.0 x10-5.Using RSR value of 2.0 gives a much lower failure probability and updated failure probability compared to the RSR value of 1.5. When the updating is made at RSR 1.5, the failure reduces down to 1 x 10-4 when the experienced wave height is at 15m, and met the requirement of the ISO 19902 code and consider safe for extension of life. This study is further discussed by evaluating the probability of failure at different current velocity profile to see the variation on the updating probability of failure.