风屏障对分体式钢箱梁桥涡振性能影响的风洞试验研究

Wind tunnel test study on the effect of wind barrier on the vortex-induced vibration of twin steel box girder

分体式钢箱梁颤振性能好,但涡振性能差,有效抑制分体式钢箱梁涡激振动是这类桥梁建设与运维必须要解决的关键问题。以某在建大跨分体式钢箱梁斜拉桥为工程背景,本文通过节段模型风洞试验,研究了护栏、中央透气格栅和风屏障等常见气动措施对分体式钢箱梁断面涡振性能的影响,提出了一种风屏障和中央透气格栅联合抑振的气动措施方案。研究结果表明:(1)分体式双箱梁断面在5个风攻角(α为0°,±3°,±5°)中均观测到大幅涡激振动,需进行主梁抑振措施研究。(2)封堵护栏不能有效改善主梁涡振性能,采用风屏障可明显降低主梁涡振振幅。(3)中央透气格栅可大幅抑制主梁涡激振动,但会出现2个涡振风速区间。(4)联合风屏障和中央透气格栅可基本抑制主梁涡激振动。

Twin steel box girder has good flutter performance,but poor vortex-induced vibration(VIV)performance.Effectively suppressing the VIV of twin steel box girder is a key issue that must be addressed in the construction and maintenance of such bridges.Taking a large-span twin steel box girder cable-stayed bridge under construction as the engineering background,the influence of common aerodynamic countermeasures such as guardrails,central breathable grilles,and wind barriers on the VIV performance of the twin steel box girder was studied through section model wind tunnel tests,and a combined VIV suppression aerodynamic countermeasures scheme consisting of wind barriers and central breathable grilles was proposed.The research results show that:(1)The section of the twin steel box girder showed significant VIV at five wind attack angles(0°,±3°,±5°),and further research on main girder vibration suppression measures is required.(2)sealing guardrails cannot effectively improve the VIV performance of the main girder,but using wind barriers can significantly reduce the VIV amplitude of the main girder.(3)the central breathable grille can greatly suppress the VIV of the main girder,but there will be two VIV wind speed ranges.(4)the combined use of wind barriers and central breathable grilles can effectively suppress the VIV of the main girder.The research findings can provide a reference for the design of aerodynamic measures for suppressing VIV of similar twin steel box girder.