Development and Validation of Fragility Functions for Buried Pipelines Based on Canterbury Earthquake Sequence Data

Abstract

This paper presents parametric fragility functions for buried pressurized water pipelines based on data collected following the 22 February and 13 June 2011 events in the Canterbury, New Zealand earthquake sequence. The fragility of buried pipelines is expressed as a repair rate and utilizes the peak ground velocity, pipe characteristics, and soil liquefaction susceptibility expressed by the cyclic resistance ratio. The model explicitly takes into account both within-model uncertainty (the misfit to the data) and between-model uncertainty based on unknown model parameters such that for each unknown parameter, the between-model uncertainty increases. The adopted framework enables a wide application of these fragility functions to analyze the seismic performance of pressurized water pipeline networks, irrespective of the available information on the analyzed system. Utilized in a retrospective analysis via Monte Carlo simulations, the proposed fragility functions yield good predictive results.