Entwerfen von Eisenbahnbrücken für dynamische Einwirkungen aus dem Hochgeschwindigkeitsverkehr

Design of high-speed railway bridges to dynamic exposure

This article deals with the dynamic behaviour of high-speed railway bridges due to crossing trains and shows the impact of specific adjustments to the dynamic response of the superstructure. Initially the dynamic behaviour of single span beams is being observed, which are, as sequential sinlge span beams, imaginably an unfavourable structure in terms of efficiency and aesthetics. Therefore, alternative structural systems are being investigated, to influence the dynamic characteristics of railway bridges during the early design stages. Because of the interaction between the crossing train and the superstructure, the impact of changes in the structural system can hardly be estimated. Continuous beams with an overall length of more than 30 m show lower dynamic responses than single span beams and can be used with much higher velocities, even with the same cross section. Especially those natural frequencies, whose natural modes show a curvature at the supports, can be increased by adding haunches. Shortening the side spans lead to an increase of all natural frequencies and resonant velocities. By using the knowledge presented in this article, the dynamic stability of high-speed railway bridges can be improved even during the early design stages.