ABSTRACT
Along with the escalation of train speed, effect of foundation on train-bridge coupling vibration response becomes more and more significant. As for a 24 m single-track double T beam on the 3-span bridge of an existing line, it is measured that 7.85 mm lateral amplitude at pier top and 8.21 mm at mid-span when a train passing through within speed of 50-70 km/h. Such violent vibration will endanger running safety. In order to find out main cause of such big displacement, a train-bridge-foundation coupling dynamic analysis model is built. In this model, the effect of foundation is simplified as the equivalent moveable and rotational spring stiffnesses at pier bottom. Result of simulation analysis shows that relative weak foundation rigidity is the major factor. On the basis of this result, several kinds of reinforcement plans are studied respectively, one is main beam reinforcement plan, another is pier reinforcement plan and the third is foundation reinforcement plan. Finally, suggestions are put forward according to dynamic simulation analyses.
