Water Distribution System Postearthquake Service Ratio Prediction with Repair Rate and Graph Index

A water distribution system is one of the lifeline systems of an urban area. Water distribution systems have been significantly damaged in past earthquakes. In this study, polynomial equations were developed to predict the postearthquake service ratio of water distribution systems. With these equations, the design of more robust water distribution systems will be possible. Parameters of the equations were service ratio of the system, repair rate of the pipes, and a graph index of water distribution system topology. The repair rate of pipes depends on the pipe, soil, and earthquake parameters, while the graph index is related to the topology of the system network. In this study, the medium articulation graph index was used. Two thousand Monte Carlo simulations were performed and mean service ratios were calculated for nine hypothetical water distribution systems with six different repair rates for each by means of GIRAFFE software. Thus, 54 mean service ratios were used in the regression analysis. Coefficients of three polynomial models were determined after regression analysis. © 2019 American Society of Civil Engineers.