Estimation of failure probability using boundary conditions of failure pressure model of buried pipelines

This paper presents the effects of boundary conditions of failure pressure model for buried pipelines on failure prediction by using a failure probability model. The first order Taylor series expansion of the limit state function is used in order to estimate the probability of failure associated with varying corrosion defects for long exposure periods in year. A failure pressure model based on a failure function composed of failure pressure and operation pressure is adopted for the assessment of pipeline failure. The effects of random variables such as defect depth, pipe diameter, defect length, fluid pressure, corrosion rate, material yield stress, material ultimate tensile strength and pipe thickness on the failure probability of the buried pipelines are systematically studied by using a failure probability model for the corrosion pipeline. Furthermore, the probabilities of each failure pressure model are compared in terms of exposure time under varying boundary conditions after the first inspection period.