为研究变截面钢桁梁人行桥人致振动舒适度及调谐质量阻尼器(tuned mass damper,TMD)的减振效果,以某京杭大运河钢桁梁人行桥为研究对象,采用有限元模拟和现场实测 2 种方式,研究钢桁梁人行桥人致振动响应.基于有限元模型,分析未安装TMD之前的桥梁振动响应,确定行人舒适度水平,讨论行人密度、阻尼比和人群激励频率等参数对其的影响,以此给出TMD设计参数,并分析了TMD质量比对减振效果的影响;对安装TMD之后的人行桥进行了现场实测,并在实测基础上,采用加速度时程和频谱分析对相应工况进行桥梁人致振动响应研究.研究结果表明:安装TMD之前,该桥加速度响应超过规范限值,需要考虑人致振动的影响;其加速度响应在一定范围内随着行人密度增长而增大,随着阻尼比的增大而减小;当行人步频接近桥梁某阶振动频率时,振动响应明显增大;安装TMD之后,该桥实测的人致振动响应有所降低,其响应规律与模拟结果较为一致.文中的研究成果可为变截面钢桁梁人行桥人致振动研究提供理论支持.
Research on human-induced vibration and vibration control of variable cross-section steel truss girder pedestrian bridge
To study the comfort level of human-induced vibration of a variable section steel-truss pedestrian bridge and the vibration reduction effect of tuned mass damper(TMD),a steel truss girder pedestrian bridge on the Beijing Hangzhou Grand Canal was taken as the research object.Finite element simulation and on-site measurement were used to study the human-induced vibration response of the steel truss pedestrian bridge.Based on the finite element model,the vibration response of the bridge before installation of TMD was analyzed,the pedestrian comfort level was determined,and the influence of pedestrian density,damping ratio and crowd excitation frequency on the bridge was discussed.In this way,the TMD design parameters were given,and the influence of TMD mass ratio on the vibration reduction effect was analyzed.On site measurements were conducted on the pedestrian bridge after the installation of TMD,and based on which acceleration time history and frequency spectrum analysis were used to study the human-induced vibration response of the bridge under corresponding operating conditions.Comparison of the results shows that before installing the TMD,the acceleration response of the bridge exceeds the specification limit,and the effect of human-induced vibration should be considered.In a certain range,the acceleration response increases with the increase of pedestrian density and decreases with the increase of damping ratio.The vibration response increases significantly when the pedestrian step frequency is close to a certain order of the vibration frequency of the bridge.After the installation of TMD,the measured human-induced vibration response of the bridge is reduced,and its response is consistent with the simulation results.The research results in this paper can provide theoretical support for the study of human-induced vibration of variable section steel truss bridge.
steel truss girderhuman-induced vibration testhuman induced vibration simulationcomfort evaluationtuned mass dampervibration control
万方数据
维普
