非对称异型箱梁斜拉桥涡振性能试验研究

Experimental study on vortex induced vibration performance of asymmetric special shaped box girder cable stayed bridge

随着现代桥梁美学的不断发展,非对称异型断面主梁在景观桥、人行桥中的应用逐渐广泛,但其气动性能受断面外形影响显著。以某异型箱梁斜拉桥为工程背景,在风洞中测试了在桥梁栏杆处安装分流板、安装主梁断面风嘴、改变栏杆外形等措施的主梁涡振性能。试验结果表明:在设计风速内异型主梁存在明显的竖向涡振,且超过了规范规定的最大幅值;当主梁钝体面迎风时,在栏杆处安装分流板能达到较好的抑制涡振的效果,但当非钝体面迎风时,却产生了负面影响;在主梁断面安装风嘴同样仅在钝体面迎风时达到了较好的抑制涡振的效果,但当非钝体面迎风时不能抑制涡振;改变栏杆外形及安装风嘴的组合措施可抑制主梁涡激共振,且能满足颤振稳定性要求。

With the continuous development of modern bridge aesthetics,the asymmetric special shaped section girder is becoming more and more widely used in landscape bridge and pedestrian bridge.However,the aerodynamic performance is significantly affected by the shape of the section.Based on the engineering background of a special-shaped box girder cable-stayed bridge,the vortex vibration performance of the main girder was tested in the wind tunnel.In test,the splitter plate was added at the railing,the cross section nozzle of main beam was installed,and the shape of railing was changed.The results show that the obvious vertical vortex vibration is induced within the design wind speed,and the vibration exceeds the maximum amplitude specified in the code.The vortex-induced vibration will be restrained by flow suppression plate at the railing,when the blunt face of the main girder is windward side.However,the negative effect can be caused,when the non-blunt face is windward side.Furthermore,the similar results are obtained by installing the cross-section nozzle of the main girder.By changing the shape of the railing and installing the air nozzle,the vortex induced resonance of the main girder can be successfully suppressed,and the requirement of flutter stability can be met.