Patrick SALCHER
Dynamic effect of high-speed trains on simple bridges
This thesis deals with the dynamic behaviour of railway bridges for high-speed trains. In particular, resonance phenomena need to be investigated utilizing dynamic analysis, since bridge spans and train velocities are increasing nowadays. These analyses need a lot of effort. Thus, there is a demand for quick and yet accurate methods to evaluate the dynamic response of these bridges. The Bernoulli-Euler beam model is used to create a numerical model of railway bridges. Both, simply-supported single-span and continuous two-span beams are examined. A repetition of concentrated loads moving with constant speed models the impact of trains on the bridge. The mechanical problem of vibrating beams is solved using the modal superposition method. The influence of the number of modes on the dynamic response is studied. Furthermore, the impact of the span length to wagon length ratio and other parameters on the resonance behaviour is subject of the present investigation. However, the main objective of this thesis is to generate diagrams, which can be used by the practicing engineer as simple design tool to determine the dynamic peak bridge response (such as deflection, acceleration, bending moment). Application of these diagrams requires only the knowledge of the non-dimensional maximum travel speed and the type of train.