Reliability of water distribution networks subjected to seismic hazard: Application of an improved entropy function

•A practical framework is developed for seismic reliability assessment of Water Distribution Networks (WDNs).•An improved entropy function is suggested to assess reliability of WDNs considering both total and partial failure.•The proposed entropy function can take into account different failure patterns caused by different hazard levels.•The efficiency of the developed reliability assessment framework is demonstrated through several practical examples. This study aims at improving an entropy-based measure considering both total and partial failure, for assessing the reliability and redundancy of Water Distribution Networks (WDNs) during seismic events, which was not explicitly addressed in previous literature. In order to capture the effects of connectivity order of the network nodes as well as the seismic hazard of the site in reliability studies, new entropy calculation method is proposed using hazard information of seismic regions and fragility curve of pipelines. Subsequently, the effect of failure of each pipe due to a seismic event, which results in reducing the serviceability and reliability of a WDN, is investigated using the proposed entropy calculation. The results indicate that the proposed entropy function is capable of estimating the reliability trend of WDNs considering different failure patterns caused by different hazard levels. The proposed method enables the engineers and practitioners to find a proper optimum design approach for the water supply network and plays an important role in assessing the performance of WDNs and mitigating the chance of total failure of WDN in hazardous zones.