Seismic functional reliability analysis of water distribution networks

Abstract

Due to the huge destructive power of strong earthquakes, many breaks appear on water pipelines after such events. As a result, water leaks from these breaks, causing function loss of water distribution networks (WDNs). In order to evaluate the seismic performance of WDNs, these leaks cannot be ignored. In this paper, by adding a leakage model to the hydraulic equation of WDNs in a daily operation state, a new hydraulic equation is established to describe WDNs after the occurrence of earthquakes. As it is a stochastic equation, a random perturbation method is used to solve the equation and give the mean, standard deviation and skewness of the nodal head. In the meantime, a performance function is established to evaluate the reliability of WDNs. Three reliability analysis methods, a mean first-order second-moment method and two third-moment methods, are used to give the seismic functional reliability of WDNs. Meanwhile, two networks, a small WDN and an actual WDN which suffered serious damages during the Wenchuan Earthquake, 2008, are studied to compare the efficiency and precision of the three reliability methods.