The vortex-induced vibration performance of a flat streamlined steel box-shaped girder with airflow-suppressing board,and that without any aerodynamic countermeasures were investigated,measuring the surface pressure of the flat streamlined steel box-shaped girder during its vibration. Means and standard deviations of fluctuated pressure,and correlations between local and total aerodynamic forces in time domain as well as power spectra of fluctuated pressure,phase spectra,coherence function of local and total aerodynamic forces in frequency domain analyzed. It was shown that the severe fluctuation of pressure with the same dominant frequencies in the middle and downstream regions or the reattachment regions,at the upper face,and the high correlation between local and total aerodynamic forces at the bottom face with the same dominant frequencies cause the vortex-induced vibration; the airflow-suppressing board destroys the severe fluctuation of pressure in the middle and downstream regions at the upper face and the high correlation between local and total aerodynamic forces at the bottom face,so the vortex-induced vibration is effectively suppressed.%通过测量大比例流线形扁平钢箱梁模型(1∶20)涡激共振时表面压力,研究典型钢箱梁常用设计断面涡激振动、静止、以及安装抑流板后涡激共振性能.综合对比分析三种工况模型表面压力系数均值、根方差、局部气动力与涡激气动力相关系数等时域统计特性；表面压力脉动的功率谱、局部测点气动力与总体断面气动力间的在模型竖弯频率处的相位谱和相干函数等频域统计特性.研究发现:竖弯涡激共振产生原因是流线模型上表面下游的气流再附区域强烈压力脉动以及箱梁下表面与总气动力具有较强相关性的压力脉动,整体断面各测点脉动压力具有相同的卓越频率.针对本项研究试验实例,抑流板措施减弱了箱梁中下游位置压力脉动的分布强度和作用时序的相关性,可以有效地抑制涡振.
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