Seismic Resilience Evaluation of Urban Multi-Age Water Distribution Systems Considering Soil Corrosive Environments

Evaluating the seismic resilience (SR) of water distribution systems (WDSs) can support decision-making in optimizing design, enhancing reinforcement, retrofitting efforts, and accumulating resources for earthquake emergencies. Owing to the complex geological environment, buried water supply pipelines exhibit varying degrees of corrosion, which worsens as the pipelines age, leading to a continuous degradation of their mechanical and seismic performance, thereby impacting the SR of WDSs. Consequently, this study proposes an SR evaluation method for WDSs that takes into account the corrosive environment and the service age of buried pipelines. Utilizing the analytical fragility analysis method, this research establishes seismic fragility curves for pipelines of various service ages and diameters in diverse corrosive environments, in combination with the Monte Carlo simulation method to generate seismic damage scenarios for WDSs. Furthermore, the post-earthquake water supply satisfaction is utilized to characterize the system performance (SP) of WDSs. Two repair strategies are employed for damaged pipes: assigning a single repair crew to address damages sequentially and deploying a repair crew to each damage location simultaneously, to assess the minimum and maximum SR values of WDSs. The application results indicated that the maximum decrease in SP across 36 conditions was 32%, with the lowest SR value of WDSs being 0.838. Under identical seismic intensities, the SR value of WDSs varied by as much as 16.2% across different service ages and soil conditions. Under rare earthquake conditions, the effect of the corrosive environment significantly outweighs the impact of service age on the SP of WDSs. Post-disaster restoration resources can minimize the impact of the corrosive environment and service age on the SR of WDSs.