A framework for performing dynamic analysis of coupled road vehicle and long span cable-stayed bridge systems under cross winds in the time domain has been developed in this dissertation. In this framework, the mechanical model of a cable-stayed bridge is established using the conventional finite element method. A road vehicle is modelled as a combination of several rigid bodies connected by a series of springs, dampers, and pivots, in which both the lateral and vertical vibration of the vehicle are included. Different from the conventional investigation of vehicle-bridge interaction, a special damper, of which the damping coefficient is dependent on unknown motion of the vehicle and the bridge, is introduced to consider the possible sideslip of the vehicle tire relative to the bridge deck in the lateral direction. The random road surface roughness is simulated through an inverse Fourier transform from a given power spectrum of road roughness. The time histories of turbulent wind velocity in the horizontal and vertical directions along with the bridge deck are generated based on a modified spectral representation approach. The turbulent wind velocity used in the calculation of wind forces on the vehicle is kept compatibility with those used in the calculation of wind forces on the bridge. Buffeting forces and self-exciting forces are simulated in the time domain using a rational function approximation approach, the aerodynamic admittance functions, the aerodynamic coefficients, and the flutter derivatives. The wind forces acting on the road vehicles are, however, assumed to be steady wind forces because of the lack of relevant test data. The equations of motion of the coupled road vehicle-bridge system under crosswinds are assembled using a fully computerised approach, taking into consideration the full interaction among the vehicles, the bridge and the crosswind. Comprehensive computer programs have been accordingly developed. A case study on the safety and ride comfort of high-sided road vehicles running over a real long span cable-stayed bridge under cross winds is finally performed, and the effects of road surface roughness, mean wind velocity, and vehicle speed are investigated. The accident vehicle speeds due to a sudden crosswind gust are obtained from a great deal of computation work, which provide a reference to traffic control of the cable-stayed bridge during windy periods. The oscillation of the cable-stayed bridge affects the accident vehicle speed considerably under higher mean wind velocity after a comparison of the safety of the vehicle running on the bridge and the ground under a sudden crosswind gust. The vertical and lateral ride comfort of the concerned road vehicle running on the bridge subjected to cross winds can meet the specified comfort criteria when the vehicle speed and mean wind are less than 80km/h and 15.0m/s, respectively.
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