钢结构人行桥的人致振动舒适度分析

Analysis of human induced vibration comfort of steel structure corridor bridge

利用有限元软件MIDAS gen对某两层大跨度、大悬挑的钢结构人行桥进行人致振动舒适度分析,依据竖向振动模态找出人行荷载施加部位(悬挑段或柱跨间),研究了不同行人密度(0.5、1、1.5和2人/m^(2))的影响,并根据振动加速度对舒适度等级进行评价,对加速度响应最敏感的部位设置调谐质量阻尼器(TMD)进行减振控制。研究表明:同时在两层的悬挑段施加人行荷载所产生的加速度响应可视为单独在某层施加人行荷载时的累加,而在柱跨间施加人行荷载时不具有累加效应;在柱跨间施加不同工况的人行荷载时,加速度响应最大值均不超过0.5m/s^(2),满足CL1舒适度等级;同时在两层的悬挑段施加人行荷载,且行人密度为1~2人/m^(2)时,悬挑段端部的加速度响应最大值大于0.5m/s^(2);设置TMD可有效降低人致振动时程响应,减振效率可达55%,减振后舒适度等级达CL1。

The finite element software MIDAS gen was used to analyze the human-induced vibration comfort of a two-story long-span, large cantilever steel pedestrian bridge. Find out the application position(cantilever section or column span) of pedestrian load according to the vertical vibration mode. The effects of different pedestrian densities(0.5,1, 1.5 and 2person/m^(2)) were studied, and judge the comfort level according to the vibration acceleration. Tuned Mass Damper(TMD) was set at the most sensitive part of acceleration response to reduce vibration. The research shows that the acceleration response caused by the pedestrian loads applied to the cantilevered section of the two floors can be regarded as the accumulation of the pedestrian loads applied to a certain floor alone, but there is no accumulation effect when the pedestrian load is applied between the column spans;when the pedestrian loads under different working conditions were applied between the column span, the maximum acceleration response does not exceed 0.5m/s^(2). meeting the CL1 comfort level. When the pedestrian loads were applied to the cantilever section of the two floors together, and the pedestrian density is 1~2person/m^(2), the maximum acceleration response at the end of the cantilever section is greater than 0.5m/s^(2). Setting TMD can effectively reduce the time history response of human induced vibration, and the vibration reduction efficiency can reach 55%, and the comfort level after vibration reduction can reach CL1.