Research On Multi-Mode Vibration Control Of Footbridge Based On Tmd

With the development of social economy and the rapid growth of urban population,in some areas,a large number of footbridges have been built to alleviate traffic pressure and ensure pedestrian safety.With the modernization development of the city,footbridges have become part of the urban landscape,thus many fashionable,beautiful but light,long-span,flexible footbridges have been born.These footbridges are less frequent,when the natural vibration frequency is close to the range of human walking frequency,the comfort of the bridge will be reduced,and even a human bridge resonance phenomenon may cause a safety accident.In order to solve the problem of excessive vibration of footbridge,the most simple and effective way adopted at home and abroad is to install tuned mass damper(TMD)on the footbridge.This paper first introduces the parameter optimization theory of TMD.Then,taking a pedestrian arch bridge and a pedestrian suspension bridge as examples,TMD is designed and vibration reduction analysis is carried out.Finally,the seismic reduction effect of TMD is analyzed.The main research contents are as follows:(1)The parameter optimization theory of TMD is introduced.Firstly,the most widely used TMD parameter optimization theory is introduced,including fixed-point theory and extended fixed-point theory,STMD parameter optimization theory and MTMD parameter optimization theory.Then the modal analysis of multi-degree-of-freedom main vibration system is introduced.Finally,the evaluation method of bridge comfort and the mode of pedestrian load are briefly introduced.(2)Vibration reduction analysis of a pedestrian arch bridge and a pedestrian suspension bridge.Firstly,the finite element model is established,and the vibration mode that needs to be controlled is determined through eigenvalue analysis,and the TMD is designed Then,under the action of fixed-point harmonic force,the dynamic response law of footbridge with TMD is analyzed,and the appropriate mass ratio range of TMD is determined.Then,the vibration reduction effect of TMD layout in theory and practice is compared,and the vibration reduction effect of TMD under various pedestrian load modes is analyzed,as well as how to distribute the TMD quality that controls the two-order mode when the TMD total mass is constant.(3)Shock absorption analysis of a pedestrian arch bridge and a pedestrian suspension bridge.By adding the TMD designed according to the pedestrian load mentioned above,the dynamic response of the footbridge under seismic action is analyzed,and the seismic reduction effect of TMD is determined.