ABSTRACT
Underground pipelines are vital to a nation’s economy, environment, and public well-being, and often regarded as societal lifelines. However, they are vulnerable to seismic actions, necessitating fragility analysis as part of lifecycle management. This paper proposes a probabilistic method to assess pipeline seismic fragility, considering uncertainties in earthquake occurrence and intensity. Ground motions are generated using a random function-spectrum model, and nonlinear dynamic analyses simulate pipeline responses under varying peak ground accelerations. By repeating these steps, the pipeline’s dynamic response statistics and probability distribution function are obtained. Given an acceptable response limit, a limit state function can be constructed, and failure probability can be determined using structural reliability methods. For different acceptable limits, a fragility curve can be plotted for different peak ground accelerations. A worked example is presented to demonstrate the method’s accuracy and efficiency. This analysis provides a scientific basis for pipeline design, operation, and risk management.
