不对称钢箱梁涡激振动性能及制振措施研究

Research on Vortex-induced Vibration Performance and Vibration Control Measures of Asymmetric Steel Box Girder

锦江人行天桥全长698 m,主桥部分上部结构为桅杆式斜拉桥,下部结构采用V形钢桥墩,主梁断面为左右不对称钢箱梁。为研究不对称钢箱梁断面的涡激振动特性,同时消除可能存在的涡激振动对主桥运营安全的影响,对主梁断面开展了1∶20节段模型风洞测振试验,针对主梁受气动干扰敏感和可调节气动外形的区域进行涡激振动气动措施研究。试验结果表明:不对称钢箱梁在前后两侧来流工况下,主梁均出现了涡激振动现象,但各工况下的涡振现象和风速锁定区间不同;对比了去除主梁栏杆和对栏杆间隔封闭的气动措施,采用对栏杆隔三封一能够抑制主梁的涡激振动。本研究所提出的制振措施可为类似工程研究提供参考。

The Jinjiang pedestrian bridge totals 698m,the superstructure of main bridge is mast type cable-stayed bridge,the substructure adopts V-shaped steel pier,and the main beam section is asymmetric steel box girder.In order to study the vortex-induced vibration characteristics of asymmetrical steel box girder section and eliminate the possible influence of vortex-induced vibration on the operation safety of the main bridge,a 1:20section wind tunnel vibration test is carried out on the main beam section,and the vortex-induced vibration aerodynamic measures are studied in the area of the main beam that is sensitive to aerodynamic interference and adjustable aerodynamic shape.The test results show that the vortex-induced vibration of the main girder occurs in both the finished and the construction state under the condition of the flow coming from the front and back sides of the asymmetric steel box girder,but the vortex-induced vibration and the wind velocity locking range are different under each condition.The aerodynamic measures of removing the railing of the main beam and sealing the railing are compared.The vortexinduced vibration of the main beam can be restrained by the pneumatic measure of sealing one at every three intervals for the main beam railing.The vibration control measures proposed in this study can provide reference for similar engineering research.