ABSTRACT
Pipelines that convey different materials like gas, water, petroleum, waste water, etc., are prone to damages caused by strong earthquakes. Because these infrastructures are mostly buried in the ground, they are affected by not only pipeline properties and seismic characteristics of the earthquake but also ground movements around the pipelines. Observed pipeline damages in the past earthquakes indicate that there is a strong correlation between pipeline damages and ground movement characteristics. Furthermore, the pipeline damages are particularly high in permanent ground deformation zones such as in liquefaction areas. The loads applied to pipelines by ground movements and resistance of pipelines against those loads should be taken into account in the design or assessment of pipelines. However, both the loading and resistance portions of the analysis contain many parameters with uncertainties associated with them. By using reliability analyses, utility companies may obtain predicted damage levels from future earthquakes, perform risk management, determine risk levels for different hazards and consequently improve their systems, or design their systems accordingly at planning stages. This chapter presents and discusses the probabilistic approach and performance function-based reliability analysis methods namely first-order second-moment (FOSM) and Monte Carlo simulation method applications on buried pipelines. Sensitivity analyses involving the key parameters and the respective uncertainties of these parameters required in the reliability analyses are discussed. The sensitivity analyses provide the classification of key seismic, pipe and ground variables quantitatively according to their importance and will be useful for reducing the risks of damage to pipelines due to the earthquakes. Case studies from past earthquakes are presented to illustrate the application and limitation of reliability and sensitivity analyses to assess the effects of ground movements during earthquakes on buried pipelines.
