PROBABILISTIC ESTIMATION OF REMAINING LIFE OF A PIPELINE IN THE PRESENCE OF ACTIVE CORROSION DEFECTS

A methodology is presented for the assessment of remaining life of a p ressurised pipeline containing active corrosion defects. A probabilist ic approach is adopted to this methodology and the associated variable s are represented by normal or non-normal probabilistic distributions. A failure pressure model based on fracture mechanics is adopted for t he assessment of pipeline failure pressure and linear idealisation of the long-term corrosion growth rate is carried out. Because of the pre sence of nonlinearity in the limit state function and also of the pres ence of non-normal variables, the Level II advanced first order second moment iterative method is employed for carrying out reliability anal yses. The methodology is applied to an example pipeline and the remain ing useful life of this pipeline is assessed. Relative contribution of the random variables and the sensitivity of the reliability index to the change in variance of the random variables is also investigated. ( C) 1998 Elsevier Science Ltd. All rights reserved.