Dynamic behaviour of asphalt concrete substructure ballastless track system in long-span railway bridge

In this paper, the dynamic behaviour of asphalt concrete substructure ballastless track system (ACSBTS) in the application of long-span railway bridge (LSRB) is clarified. Firstly, the finite element model of full LSRB was established, which considered the viscoelastic properties of asphalt concrete and the vibrational load condition of high-speed train. Particularly, the asphalt concrete properties were characterised using generalised Maxwell model. Then, the dynamic responses of different components in ACSBTS were calculated and compared with those of cement concrete substructure ballastless track system (CCSBTS). Moreover, the LSRB vibration modes were discussed. Lastly, the effect of different influence factors was investigated. Results show that asphalt concrete substructure can mitigate the mechanical responses induced by dynamic train load. It is suggested that the asphalt concrete substructure thickness should preferably not exceed 350 mm and its modulus could be increased appropriately. Findings contribute to the application of ACSBTS in LSRB.