大跨度钢拱桥吊杆减振的新型电涡流TMD开发与应用

Development and Application of a New-type Eddy Current TMD for Vibration Control of Hangers of Long-span Steel Arch Bridges

针对吊杆频率低、阻尼小、易发生风振的弱点,以厦深线榕江特大桥钢吊杆为工程背景,首先通过风洞试验、理论分析和现场实测评估了吊杆的抗风稳定性以及减振设计所需参数。然后基于被动控制和电涡流耗能原理,采用等强度悬臂梁开发了一款耐疲劳、免维护的新型电涡流TMD(被动调谐质量阻尼器)用于改善吊杆风振性能。最后通过强迫振动法实测了吊杆-TMD系统的等效阻尼比以评估其减振效果。试验结果表明:开发的新型减振系统可以使长吊杆强轴(横桥向)和弱轴(顺桥向)的阻尼比分别达到1%和3%以上,完全满足台风区钢拱桥吊杆减振的需要。

Aimed at the hangers with low natural frequencies, light damping and frequently suffered from wind-induced vibrations, on the basis of the practical engineering of Rongjiang Bridge of Xiashen Line, the wind-resistance stability and the parameters for vibration control of hangers were evaluated through wind tunnel test, theoretical analysis and field measurement. Then a novel on eddy current TMD （tuned mass damper） device, with anti-fatigue and maintenance-free was developed to improve the hangers＇ wind-resistance stability on the basis of passive control, eddy current consumption theory and intensity equivalent beam. Finally, the hanger-TMD system＇s equivalent damping ratio was obtained by the forced vibration method to evaluate the vibration control effect. The results show that the measured mechanical damping ratios of hangers with the new-type eddy at strong axis current TMD devices are respectively improved to the level of over 1% cross bridge direction and 3% at weak axis along bridge direction, which can fully meet the needs of the vibration control of hangers in long-span steel arch bridges in typhoon areas.