Analysis of Pipeline Failure Probability Caused by Earthquake Based on the Allowable Strain

The earthquake happened in WenChuan city, SiChuan province of China on twelfth June 2008 had greatly impacted the integrity of LanChengYu pipeline, which is the only way of providing product oil to SiChuan province. The pipeline designers have paid more attention to the threat of earthquake after that. This paper reviewed the traditional methods of calculating pipeline failure frequency caused by earthquake, and pointed out their shortcomings. In addition, a new method was provided. Firstly researchers should calculate the additional strains of pipe caused by earthquake which related to the peak ground acceleration (PGA). The method of additional strains calculation was provided in the Chinese industry standard SY/T 0450. Secondly the uncertainty calculation was conducted to get the rule of distribution. Finally the additional strain was compared to the allowable strain of pipe, and the probability of exceeding is the pipeline failure frequency caused by earthquake. Further An example was followed. The parameters needed were listed, and the pipeline failure frequency along the station was illustrated. The result may be useful to pipeline designers.