RELIABILITY OF UNDERGROUND PIPELINES SUBJECT TO CORROSION

The present paper is concerned with estimating the reliability of unde rground pipelines subject to externally applied loading and to corrosi on, either externally or internally, or both. This affects the strengt h of the pipeline in resisting the applied loads so that the reliabili ty would be expected to decrease with time. Corrosion is a phenomenon about which there is a great deal of uncertainty. One way of allowing for this is through probabilistic modeling of the material loss as a n onlinear function of time. This approach is explored in the present pa per, using a nonlinear function first postulated for atmospheric corro sion. This model is incorporated into expressions for stress resulting from externally applied loading and internal pressure to provide a li mit state function expressing the boundary between survival and failur e of the system. The probability of system failure is then evaluated u sing techniques developed for structural reliability analysis.