基于节段模型试验的宽幅箱梁涡振性能气动措施优化

为了研究宽幅流线型箱梁断面的涡振性能,以某跨越长江的大跨悬索桥为背景,进行1∶50节段模型风洞试验。分析了检修轨道、人行道栏杆等涡振敏感构件的影响,研究了改变人行道栏杆形式、附加斜腹板导流板以及风嘴分流板等气动措施的制振效果。研究结果表明,宽幅箱梁涡振性能随来流攻角增大而逐渐变差,且由于漩涡Strouhal数的变化易诱发多区间涡振,扭转涡振幅值随阻尼增加线性衰减显著。人行道栏杆是此类断面的涡振敏感构件,去掉栏杆踢脚石能明显改善涡振性能;斜腹板导流板对改善其涡振性能效果微弱;风嘴分流板具有显著的制振效果,不仅能有效地抑制主梁涡振的发生,且能提高颤振临界风速。

On the Aerodynamic Optimization Measures for Vortex-Induced Vibration Performance of Wide Box Girder based on Section Model Experiment

In order to investigate the vortex-induced vibration (VIV) performance of wide streamline box girder,taking a large span suspension bridge across Yangtze River as background,wind tunnel experiment for 1∶50 section model was carried out.In this paper,the influence of overhaul track,sidewalk guardrail and other vortex-induced vibration sensitive components was analyzed,and vibration suppression effect of aerodynamics optimization measures,such as changing the form of sidewalk guardrail,the additional oblique web guide plate and nozzle split plate was studied.Results show that the vortex-induced vibration performance of wide box girder is gradually become worse with the increase of flow attack angle;due to the change of vortex strouhal is easy to induce multi section vortex vibration,the linear attenuation of torsional vortex amplitude is more obvious with the increase of damping.Sidewalk guardrail is a vortex-induced vibration sensitive component for this type section,removing stone railing skirting can significantly improve the performance of vortex-induced vibration.The effect of oblique web guide plate on improving performance of vortex-induced vibration is weak.Nozzle split plate has obvious effect on vibration suppression.It can not only effectively suppress the occurrence of vortex-induced vibration on main beam,but also can raise the critical flutter wind speed.