Evaluation of a steel railway bridge for dynamic and seismic loads

In this study, dynamic and seismic assessment of a railway bridge system with four discrete spans giving service on a double track railway line and located in an earthquake-prone region in Turkey is presented. A three-dimensional computer model of the bridge was generated using a commercial general finite element analysis software. Field measurements such as static and dynamic tests as well as material tests were conducted on the bridge system. Validation of the finite element model was performed based on the results of these tests. The calibrated 3D model of the bridge structure was then used for necessary calculations regarding structural assessment and evaluation according to train loads as well as seismic loads. Additional members were proposed to transmit seismic loads to supports. The fourth span, which had a permanent imperfection due to truck collision was studied in detail. Results have shown that due to excessive amount of capacity loss, the only choice was to write off the fourth span.