Abstract:
In order to evaluate the dynamic response of common continuous girder bridges under vehicle-bridge coupling in detail, this paper uses numerical simulation method to establish the finite element model of five-span continuous girder bridges with general drawings of bridges and culverts, and analyzes its dynamic responses under vehicle loads: deflection, stress. The corresponding dynamic amplification factor is calculated, and the variation law of dynamic amplification factor under the influence of vehicle frequency, bridge frequency and disturbance frequency is compared. The research shows that the fundamental frequency of the continuous beam bridge in the general drawing is 4.44 Hz. When the vehicle frequency is close to the fundamental frequency of the bridge, the resonance effect will be produced and a larger dynamic amplification factor will be produced. The variation law and numerical value of the dynamic amplification factor at the middle position of the middle span and the middle position of the secondary side span obtained from the calculation are close to each other, but there are some differences with the dynamic amplification factor at the middle position of the side span, which shows that the structure with one end simply supported at the side span has a great influence on the dynamic amplification factor here. Vehicle frequency, bridge frequency and driving disturbance frequency all affect the dynamic amplification factor, so the impact coefficient in the bridge specification is only a function of the fundamental frequency of the bridge, which is far from the reality and needs to be improved.