Dynamic Analysis of Railway Bridges Considering the Nonlinear Amplitude-Dependent System Behaviour - Simulation and in-Situ Tests

Abstract

The train-induced forced vibration responses of railway bridges are investigated and evaluated under consideration of nonlinear effects. The considered nonlinearities refer to the amplitude dependency of the natural frequencies, which was observed during in-situ measurements conducted by the authors for several existing railway bridges of different construction type. The nonlinearities detected during dynamic measurements on existing railway bridges are presented and discussed. The focus is on single-span steel and concrete slab bridges with ballasted superstructure. Numerical simulations of train crossings are carried out under assumption of nonlinear beam models for the considered railway bridges. The amplitude dependency of the natural frequencies is considered in these nonlinear simulations and the structural responses during train crossing are presented in the form of resonance curves. For comparison purposes, the calculations are also carried out on linear beam models with constant natural frequencies and the resulting deviations are discussed. The influence of the investigated nonlinearities on the vibration response behavior of railway bridges is highlighted and recommendations for the future consideration of these effects in dynamic calculations of train crossing are given.