Assessment of the significance of the bridge-train interaction in dynamic analysis of bridges subjected to moving loads

The paper reports the applications of a numerical package DBTI developed by the authors to a study on bridge-train dynamics and interaction. Within the package, bridges were modelled with beam-type finite elements and trains are represented by sets of multi-body vehicle models. The main aim of this study was to investigate key parameters governing the dynamic response of bridge-train systems and to assess the significance of the bridge-train interaction in relation to these parameters. A number of factors were considered that included speed, as well as frequency and mass parameters. Dynamic response of bridge-train systems was comprehensively analysed by means of displacement-based and strain-based dynamic amplification factors, as well as bridge accelerations. The significance of the bridge-train interaction was assessed for each of these response indicators. This represents progress in comparison with previous studies where normally, no more than two-types of response indicators were used to investigate the bridge-train dynamics. The level of the bridge-train interaction was found to vary significantly with the speed parameter. The interaction was also shown to become increasingly important for higher values of the frequency and mass parameters. Based on the study, general criteria for neglecting the bridge-train interaction are provided in the paper.