Influence of Ballast Track on Vertical Response of Multi-span Simply-Supported Bridges Under Railway Traffic

In this contribution the vertical response of multi-span single-track simply-supported railway bridges is addressed. The main objective is to assess the influence of the track components and its continuity on the bridge acceleration response under the passage of railway convoys. To this end, a preliminary bidimensional numerical model is presented including a discrete model for the track. The model is calibrated with the proof load test results performed on the structure in the past. A sensitivity analysis is performed showing the effect the track components stiffness and damping considered under resonant and non-resonant conditions. Finally, a recent experimental campaign performed by the authors on an existing bridge is presented and the structural response under two trains is compared with numerical predictions. Preliminary conclusions regarding the effect of the track components and the ballast coupling between adjacent decks are finally extracted.