Seismic vulnerability assessment of buried corroded steel pipes under different site conditions

A nonlinear interaction analysis model for pipelines and soils is established to evaluate the anti-seismic performance of corroded steel pipes buried in different sites. Based on the incremental dynamic time-history analysis method, the seismic vulnerability of corroded steel pipes in different sites is analyzed by taking the structural strain of buried steel pipes as the performance parameter. The results show that under the same site condition and service age, the probability of pipelines in a basically intact state decreases gradually, while that in a seriously damaged state increases gradually with the increase of earthquake intensity. Under the same site condition, the slope of the curve of moderately damaged limit becomes significantly larger than that of the curve of basic ally intact limit, but the failure rate of pipelines decreases gradually with the increase of their service age. In the weak site, the pipelines with 50 years of service age are moderately damaged when the seismic fortification intensity is 8 degrees. Under the same earthquake intensity and service age, the failure probability of the pipelines that reaches the basically intact limit and moderately damaged limit gradually increases with the decrease of the site equivalent shear wave velocity. The failure probability is the highest in the weak field. Under the same service age, the peak acceleration of ground motion that the pipelines reach the moderate damage or severe damage decreases obviously with the decrease of the site equivalent shear wave velocity. The damage of pipelines in soft field at lower seismic intensity is even higher than that in hard field at higher seismic intensity. This study may provide reference for the earthquake damage prediction and post-disaster loss assessment of buried corroded pipelines in different sites.