Abstract:Large-span footbridges are difficult to meet the requirements of current norms in China that the vertical natural frequency of footbridges should not be less than 3Hz. In order to study the human-induced vibration and comfort evaluation criteria of footbridges, taking a steel truss pedestrian landscape bridge in a scenic area as a case, a finite element model is established by using MIDAS Civil software for the analysis on the dynamic characteristics of the bridge. According to the German EN03 norm, the acceleration response analysis and comfort evaluation are carried out for the structure under different pedestrian densities. And by optimizing the parameters of tuned mass damper (TMD), the influence of TMD installation position and quantity on the acceleration response of the structure is analyzed, and the reasonable damping scheme is determined. The results show that with the increase of TMD mass ratio, the peak value of vertical acceleration of the structure decreases and the damping ratio increases. However, the damping effect does not increase linearly with the increase of mass ratio. When the mass ratio is greater than 2%, the damping effect has tended to be gentle. Combined with the engineering practice, the comfort of structure reaches a “very comfortable” level when the mass ratio is 1% and two TMD are set in mid-span, which can effectively control the human-induced vibration. The research results can provide some reference values for the design of similar footbridges.
