Influence of ballast models in the dynamic response of railway viaducts

This paper presents an investigation of the numerical, dynamic response of medium-span railway viaducts by taking into account the influence of the ballasted track and the loadmodelling methodologies. Three models for the track and two loading procedures (the Moving Forces procedure and the Train-Structure Interaction procedure) were used. The comparison was made using three case studies. Model calibration using available response-acceleration measurements showed that time variation of the first natural frequency must be assumed to reproduce the measured time histories. The influence of track models was detectable in the time domain for only the maximum accelerations. When response is analysed in the frequency domain, results show that track models act as a filter for the high-frequency components. When the Moving Forces load model was used, the effect of the track models was less significant but consistent with the previous conclusion.