Prediction of transportation volume loss by earthquake in railway network based on functionality loss curves and OD matrix method

This study proposes a methodology for predicting the extent of transportation loss in a newly developed railway network during seismic events. In this process, a direct estimation method for the OD (Origin-Destination) matrix was employed to derive the population movement ratio for each railway line, which was then used to estimate the approximate volume of transported population across the railway network. The transportation volume was estimated using the actual boarding and alighting data from a railway line in Seoul and a destination-based OD Matrix model. Next, the functionality loss of each structural component in the railway network was derived by integrating seismic fragility curves with restoration curves. The functionality loss of individual railway infrastructure components was evaluated for earthquake magnitudes ML=6 and ML=7, using the Korean ground motion attenuation equation, epicentral distance, and short-period amplification factors. Subsequently, the overall average functionality loss of the railway network was calculated by incorporating the functionality loss and length of each railway line. For a more conservative assessment, the maximum functionality loss within each segment was also considered. As a result, for an earthquake with magnitude ML=6, the transportation loss of the simulated railway network was estimated to be 7.65% when reflecting the average functionality loss, and 15.13% when reflecting the maximum functionality loss. Subsequently, under an ML=7 earthquake scenario, the transportation loss for the simulated railway network was predicted to be 19.37% when reflecting average functionality loss and 30.14% when reflecting maximum functionality loss.