Seismic reliability analysis of underground pipelines based on probability density evolution method

In this paper, a new approach for the dynamic reliability assessment of finite element modelled underground pipeline structures under earthquake excitations with uncertain parameters is proposed. The approach is established based on the thoughts of the newly developed probability density evolution method, which is capable of capturing the instantaneous probability density function (PDF) and its evolution of the responses of nonlinear stochastic structures. Associated with the physics-based stochastic earthquake model and the finite element method, the instantaneous probability density and the evolution process for the seismic response of underground pipeline can be studied effectively. The first-passage reliability problem is investigated from the level-crossing process to analyze the reliability of underground pipelines under seismic excitations. Using the proposed method, numerical examples are investigated considering stochastic input and soil parameters simultaneously. The examples show that the proposed method is of high application in analyzing the reliability of underground pipeline.