Flow-based seismic risk assessment of a water transmission network employing probabilistic seismic hazard analysis

In this study, a seismic risk assessment model was proposed to evaluate the seismic reliability of a water transmission network. The proposed risk assessment model involves earthquake generation and hydraulic analysis modules. To consider a comprehensive approach, the numerical simulation strategy includes probabilistic seismic hazard analysis, buried pipeline deterioration, numerical modeling of network facilities, and the interdependency between pumping plant and substation. For this purpose, a flow-based MATLAB code has been developed that enables iterative hydraulic analysis using EPANET software. For numerical simulation, the epicenter and earthquake magnitudes were determined based on probabilistic seismic hazard analysis, and a real water transmission network in South Korea was constructed. From the numerical results, two performance indicators (system serviceability and nodal serviceability) and four mean normal status ratios of facilities were adopted to evaluate the network performance. In addition, a component importance measure of facilities in a network system was calculated by introducing a reduction factor. The numerical results using the proposed flow-based model show that the system performance is affected by buried pipeline deterioration and network interdependency, as well as the location and magnitude of the input earthquake. It is thus concluded that the seismic risk assessment of a water transmission network should be performed using a model with a comprehensive approach.