Evaluation of Railway Bridge Responses to Blast Vibrations and Earthquake Ground Motions Based on Numerical Simulation

In this study, the dynamic responses of railway bridges generated by both blast motions and earthquakes are comparatively studied. A numerical model of a three-span continuous prestressed concrete (PSC) box girder bridge, a representative type of railway structure, was developed to investigate its dynamic performance. Dynamic analyses were conducted under two blast-induced ground motions and four earthquake ground motions, and the structural responses at the girder top were employed to evaluate the dynamic behavior of the railway bridge. The results indicate that the blast-induced bridge responses are relatively small compared to the earthquake-induced bridge responses (2–3% of the bridge response). This implies that the blast vibration limit provided in the Korean standard manual could be excessively conservative when applied to the railway bridges. Also, the results show that the blast vibration limit should be revisited, with a consideration of different structures and conditions.