Earthquake Reliability of Lifeline Networks


Abstract: Lifelines such as pipelines, transportation, communication and power transmission systems are networks which extend spatially over large geographical regions. The quantification of the reliability (survival probability) of a lifeline under seismic threat requires attention, since the proper functioning of these systems during or after a destructive earthquake is vital. In this study, a comprehensive probabilistic model for the assessment of the reliability of lifelines under earthquake loads is developed. Network reliability analysis mainly deals with the evaluation of the performance of a network in terms of its ability to withstand the failure of its components. A lifeline is idealized as an equivalent network with the capacity of its elements being random and spatially correlated. The seismic hazard that the network is exposed to is described by a probability distribution derived from past earthquake data. The seismic hazard analysis is based on the ``classical'' seismic hazard analysis model (Cornell, 1968) with some modifications. For the evaluation of the network reliability, an efficient algorithm developed by Yoo and Deo (1988) is utilized. This algorithm eliminates the CPU time and memory capacity problems that are encountered in large networks. A software package, called LIFEPACK, is coded to carry out the numerical computations. Two detailed case studies are presented to show the implementation of the proposed method.

Keywords: Network reliability, lifelines, earthquake, seismic hazard analysis, spatial correlation.

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