Dynamic Response Analysis And Vibration Control Of A Pedestrian Bridge

With the rapid development of modern science and technology,pedestrian bridges are developing in the direction of large span,softness and beauty,but some drawbacks are inevitably exposed.Some pedestrian bridges with low self-vibration frequency and small structural damping may be motivated by pedestrian walking.However,the resonance phenomenon of pedestrian bridges affects the comfort of pedestrians and causes panic.Therefore,it is especially important to control the vibration comfort during the design stage of the footbridge.However,so far,there is no regulation on the vibration comfort of the footbridge in China.In this context,this paper has carried out research on human-induced vibration test,dynamic response analysis,comfort evaluation and vibration control of a steel box beam pedestrian bridge.The main work is as follows:Firstly,the vibration test of the pedestrian bridge under the pedestrian load is carried out.The natural frequency and damping ratio of the pedestrian bridge and the dynamic response of different pedestrian density are measured by the data acquisition and analysis system.The gait parameters of pedestrians in the footbridge were counted,and the walking characteristics and parameters of pedestrians on the footbridge were obtained.Secondly,the finite element analysis software Midas Civil was used to establish the model of beam element and plate element for the footbridge,and the dynamic characteristics of the footbridge analyzed by the two model elements were compared with the experimental results based on the principle of combination of test and finite element analysis.The results were basically consistent with each other,thus verifying the accuracy of the test and model.On this basis,the selection of the ISO standards and the building vibration load standard of pedestrian load model,on the pedestrian bridge dynamic response analysis under different density of pedestrians,the standard of evaluating and refer to the corresponding to the footbridge is evaluated,and proposed to peak acceleration as the footbridge vibration comfort evaluation index in our country,steel box girder footbridge peak vertical vibration acceleration limit of0.45 m/s2.Finally,the vibration control measures of the footbridge are studied.By comparing the advantages and disadvantages of different vibration control methods,the vertical damping control of the pedestrian bridge is carried out by means of an additional tuned mass damper,and this is designed according to the parameter optimization formula.The TMD and MTMD models of the footbridge have a dynamic response analysis of the footbridge after the additional vibration-damping control device.From the analysis results,whether the single TMD or the MTMD system work together,the footbridge is after the additional damping device,thevibration comfort meets the specifications,but the MTMD system has better stability and practicability than a single TMD.