Reliability analysis of long term pitting corrosion of welded marine steel pipelines

Quantification of long term integrity for steel marine pipelines and containing structures is important for predicting future remaining service life. Often that is limited by the occurrence of wall perforation. The present paper outlines a statistical extreme value analysis that considers the variability of the maximum pit depth and its changing behaviour with long-term exposure. Pitting in the weld heat affected zone is considered critical in the analysis. To assess the effect of the level of variability of the random variables on the failure probability a sensitivity study is carried out for a typical example problem. The results show that pit diameter has a high influence, followed by the pitting corrosion parameters, on the probability of failure.