开槽变截面人行桥的气动性能与TMD减振研究

Study on aerodynamic performance and TMD vibration damping of foot bridge with slotted variable cross-section

针对开槽变截面这一新型桥梁断面,为研究其颤振与涡振性能,以某人行桥为工程背景,制作缩尺比为1/29的全桥气弹模型进行风洞试验。设计电涡流杠杆式和悬臂式TMD,研究其减振效率。研究表明:在0°和±3°风攻角和0°,15°,30°,45°,60°和90°风偏角下,主梁颤振临界风速均大于颤振检验风速(104.4 m/s);设计基准风速范围(0~58.4 m/s)内,在0°和±3°风攻角及0°,15°和30°风偏角下,主梁发生1阶竖弯、1阶扭转及2阶竖弯涡振;与0°风攻角相比,在+3°风攻角下,1阶与2阶竖弯涡振风速锁定区间有延迟,振幅分别减小和增大;布置TMD之后,涡振风速锁定区间几乎不变,振幅最大值对应的风速减小,振幅分别减少46%,47%和77%。

In order to study the flutter and vortex-induced vibration performance of bridge with the slotted variable cross-section,the whole-bridge aeroelastic model of a foot bridge was made for wind tunnel test with a scale of 1/29.The TMD of lever and cantilever type were designed to test their vibration reduction efficiency.The results show that the critical flutter wind speed of the main girder is higher than that of the flutter test wind speed(104.4 m/s)at wind attack angle of 0°,±3°and wind deflection angle of 0°,15°,30°,45°,60°,90°;within the design reference wind speed(0~58.4 m/s),the main girder has vortex-induced vibration of first-order vertical bending,first-order torsion and second-order vertical bending at wind attack angle of 0°,±3°and wind deflection angle of 0°,15°,30°.Compared with 0°wind attack angle,the wind speed lock range of first and second order vertical bending vortex-induced vibration has delay at+3°wind attack angle,and the amplitude decreases and increases,respectively;After TMD is installed,the locking range of vortex-induced vibration wind speed is almost unchanged,and the wind speed corresponding to the maximum amplitude decreases,the amplitude is reduced by 46%,47%and 77%,respectively.