An experimental and theoretical study of rail irregularities andtheir effects on railway bridge dynamics

Vertical track irregularities represent an important source of excitation during the passage of vehicles over railway bridges. The rail irregularities are usually modelled as random stationary and ergodic processes in space, characterized by their power spectral density function. In this study, the track irregularities are treated as known quantities by using the data measured from an Italian railway near Messina. Such measurements have been carried out to investigate the causes of a recent railway disaster. The train-rails-bridge system is modelled by applying a recently proposed substructure approach, which enables to handle simultaneously the dynamic responses of the vehicles, rails and bridge, taking into account the interaction among the three subsystems. The substructure model in conjunction with the experimental data is used to investigate the influence of vertical track irregularities on both bridge and vehicle vibrations.