搭载给水管的宽幅流线型钢箱梁涡振性能及抑振措施研究

Research on vortex vibration performance and vibration suppression measuresof wide streamlined steel box girder with water supply pipe

为研究给水管不同设置位置对宽幅流线型钢箱梁的涡振性能影响及涡振抑制措施,以某大跨度扁平钢箱梁斜拉桥为研究对象,制作缩尺比为1:50的钢箱梁刚性节段模型进行风洞试验和数值模拟计算。首先对比分析了风攻角为0°、±3°时,给水管设置在主梁风嘴内(Ⅰ型)和设置在桥面上(Ⅱ型)两种不同断面形式的主梁涡振特性;并采用数值模拟探究了给水管对主梁涡振性能影响的作用机理。其次,研究了结构阻尼比对Ⅰ型断面主梁涡振性能的影响;最后,通过试验测试了栏杆透风率、栏杆抑流板等气动措施对Ⅰ型断面主梁涡振性能的影响。试验结果表明:给水管是涡振敏感构件,对于Ⅰ型断面,风攻角为-3°时,主梁未出现涡振现象;风攻角为0°时,有小幅涡振响应;风攻角为+3°时,出现明显的涡振现象;Ⅱ型断面主梁无涡振现象发生。数值模拟结果显示,给水管放置在主梁外部可以有效降低上表面旋涡的尺寸,从而抑制涡振的产生。增大结构阻尼比可以有效抑制主梁的涡振;改变栏杆透风率抑振效果不明显;设置抑流板对抑振效果明显。

In order to study the effect of different locations of water supply pipes on the vortex-induced vibration(VIV)performance of a wide streamline steel box girder and the suppression measures of VIV,a large-span flat steel box girder cable-stayed bridge was taken as the research object,and a rigid section model of the steel box girder with a scale of 1∶50 was made for wind tunnel tests and numerical simulation calculations.Firstly,the VIV characteristics of the main beam were compared and analyzed when the wind attack angle was 0°and±3°,with the water supply pipe installed in the main beam wind faring(Type I)and on the bridge deck(Type II).And the mechanism of the effect of water supply pipes on the VIV performance of the main beam was explored through numerical simulation.Secondly,the influence of structural damping ratio on the VIV performance of I-shaped section main beams was studied.Finally,the effects of aerodynamic measures such as railing ventilation rate and railing flow suppression plate on the VIV performance of the I-section main beam were tested through experiments.Experimental results show that the water supply pipe is a vortex sensitive component,and for the I-shaped section,when the wind attack angle is-3°,there is no VIV phenomenon in the main beam.When the wind attack angle is 0°,there is a small amplitude of vortex response.When the wind attack angle is+3°,there is a significant VIV phenomenon.There is no VIV phenomenon in the main beam of Type II section.Numerical simulation results show that placing the water supply pipe outside the main beam can effectively reduce the size of the upper surface vortex,thereby suppressing the generation of VIV.Increasing the structural damping ratio can effectively suppress the VIV of the main beam.The effect of changing the ventilation rate of the railing to suppress vibration is not significant.Setting up a flow suppression plate has a significant effect on vibration suppression.