港珠澳大桥大挑臂钢箱梁涡激振动特性及抑振措施

Vortex-induced vibration of steel box girder with large projecting slab and its mitigation countermeasures for Hong Kong-Zhuhai-Macao Bridge

港珠澳大桥采用的大挑臂钢箱梁外形较钝,在常遇风速下易发生涡激振动。该文通过一系列节段模型和全桥气动弹性模型风洞试验,详细研究了各种气动措施和阻尼措施对此类断面涡激振动性能的影响。结果表明:大挑臂钢箱梁截面存在2个竖向涡振区和1个扭转涡振区;依据涡振振幅和发振风速区间,通航孔斜拉桥需关注第2个竖向涡振区,非通航孔连续梁桥需关注第1个竖向涡振区;在栏杆上安装弧形扰流板的气动措施可有效改善其涡激振动性能;增加结构阻尼可显著降低其涡振振幅,阻尼比达到1.0%时,涡激振动基本消失,该阻尼限值可作为港珠澳大桥的调谐质量阻尼器的依据;最后,利用三维非线性涡振分析方法对节段模型和全桥气弹模型风洞试验结果的一致性进行了讨论。

Steel box girder with large projecting slab applied in Hong Kong-Zhuhai-Macao Bridge(HZMB),is very prone to vortex-induced vibration(VIV)due to its bluff configuration.A series of section models and full aeroelastic bridge models wind tunnel tests were conducted to investigate the effects of aerodynamic measures and additional damping measures for mitigating the VIV of HZMB.The results show that two vertical VIV regions and one torsional VIV region were observed during the wind tunnel tests.According to the VIV amplitude and wind speed range of each case,the particular attention should be paid on the second vertical VIV region for the cable-stayed bridges of navigable span and the first vertical VIV region for the continuous beam bridges of non-navigable span.The VIV performance of the bridges was efficiently improved by installing arc-shaped guide vane on guardrails.In addition,the VIV amplitude were reduced significantly by increasing additional damping,and the VIV phenomenon disappeared when the damping ratio increases to 1.0%,which can be used for the design of the tuned mass damper(TMD)for HZMB.Finally,the consistency of wind tunnel test results between section model and full bridge aeroelastic model was discussed by three-dimensional nonlinear VIV analysis method.