Combination of line sampling and important sampling for reliability assessment of buried pipelines

In this article, a novel approach for estimating the time-dependent reliability of a buried pipe under the impact of internal and external stresses by combining line sampling and important sampling is proposed. The stresses are analysed given the severe effect of corrosion on the performance of underground pipeline. The effect of corrosion during the design life of buried pipe decreases the capability of the pipe wall to sustain the stresses that occur internally or externally. Herein, the failure conditions of total axial stress and the ovality–stress due to point load in conjunction with the adverse effect of corrosion are examined using the proposed computational framework. The quantification of pipe failure due to these stresses is usually challenging because of the imprecision in the determination of the structural parameters. Therefore, the approach is used to capture and evaluate the influence of randomness behaviour of the parameters of pipe and soil in estimating the structural reliability. The proposed method can be applied to any structural engineering problems. In this study, a buried pipe under a roadway is examined and the effect of the underground water table on the performance of buried pipe over time is investigated. The outcome shows that a continuous increase in underground water table can aggravate the likelihood of the buried pipeline to fail. A parametric and sensitivity assessment of corrosion parameters shows their significant contribution to the probability of failure.