Comparative Evaluation of Topological and Flow-Based Seismic Resilience Metrics for Rehabilitation of Water Pipeline Systems

Abstract

Whereas the continuous functioning of water distribution pipeline systems is important during normal times, it is paramount in the event of disasters such as earthquakes that are usually followed by fire accidents. Past earthquakes resulted in severe damage to water pipelines rendering supply systems dysfunctional in a short period of time. Consequently, it is imperative to make water supply systems sufficiently resilient to seismic hazards in order to ensure better performance and faster recovery after earthquakes. There are several types of resilience metrics that were previously proposed for aiding the seismic resilience enhancement of water supply systems. This paper evaluates two such popular types, namely, topology-based and flow-based metrics, by investigating their respective capabilities in enhancing system resilience to seismic hazards. A serviceability index is defined and used to compare the performances of rehabilitated water systems for each type of resilience metric. A section of a large-scale water supply system that is vulnerable to earthquakes is leveraged in this study for the comparative performance analysis. It is found that the topology-based seismic resilience metric is on average only 80% as efficient as the flow-based metric for the studied water network. Although the flow-based metric seemed relatively superior, it suffers from the need for significant computational time. The resulting trade-off needs to be further investigated using water networks operated in multiple seismic regions.