Seismic fragility curve for railway track constructed in railway bridge based on numerical method

In this study, a series of dynamic numerical analyses of railway bridges was performed to develop seismic fragility curves for track structures constructed on railway bridges. A 3-span continuous PSC box girder bridge, widely used for the railway structure, was numerically modeled, and the dynamic analysis of the bridge under various earthquake motions was performed. The dynamic response of the bridge at the top of the girder was used to evaluate the performance of the railway track during an earthquake. The damage states of the track structures were derived using maintenance guidelines in Korea. Seismic fragility curves for the track structure constructed on the railway bridge were established based on the dynamic numerical analysis results and the damage state according to the lateral displacement. According to the proposed seismic fragility curve, the probabilities of slight, moderate, and extensive damage by an earthquake with a return period of 1,000 years were 29%, 19%, and 8%, respectively.