An analysis method of vehicle-bridge coupling vibration considering effects of expansion joint parameters and its application

Parameters' change of expansion joints has significant impact on the vehicle-induced dynamic response of bridges. However, it is uneconomical to conduct health monitoring to evaluate the technical condition of expansion joint. To indirectly evaluate the service performance of expansion joint and clarify the impacts from variations of the expansion joint parameters on the vehicle-bridge coupling vibration response, an analysis method of vehicle-expansion joint-bridge coupling vibration (VBCV-J) was established and verified. Then, taking a long-span concrete filled steel tubular arch bridge as the prototype, the vehicle-bridge coupling vibration response were studied using the VBCV-J model while considering the cases of design parameters and variation parameters of the expansion joint. The results show that, for the design parameters, the dynamic amplification factor (DAF) of the expansion joint and the beam-end measuring points of the main girder are significant. The DAFs of the short suspenders near the expansion joint is also greater than that of suspenders in the 1/4 span and 1/2 span. For the variable parameters, the variation in the height difference between the middle transverse girder and the side transverse girder will lead to a significant increase in the vehicle-induced impact on the end of the main girder, the short suspender, and in the reaction force of the supports. The decrease of the support stiffness will also make the DAFs of the above components exceed the design value. The variation of the vehicle-induced dynamic response of main beam-end and suspenders can indirectly reflect the service performance of expansion joint.