Π型叠合梁斜拉桥涡振性能及气动控制措施研究

为研究Π型开口截面主梁的涡振性能并提出合理性控制措施，以某跨海叠合梁斜拉桥为研究对象，进行一系列节段模型风洞试验。研究表明，Π型开口截面主梁在低风速下易发生涡激共振，且该桥涡振现象在阻尼比<1%以下范围内均存在；桥面防撞栏杆及检修道护栏采用圆截面形式有利于减小涡振振幅；改尖角度风嘴能显著抑制涡激共振，且风嘴角度越小控制效果越好；桥梁断面底部双主肋转角处设置水平隔流板能有效减小甚至消除涡激振动，在一定范围内增加板的悬挑宽度对控制效果有利。

Vortex-induced vibration performance of a cable-stayed bridge with Π shaped composite deck and its aerodynamic control measures

To study the vortex-induced vibration (VIV) and its control measures for a Π shaped deck, the aerodynamic performance of a cross-sea cable-stayed bridge was investigated through section-model wind tunnel tests. The research results show that the Π shaped deck concerned suffers remarkable VIV at low wind velocity, which exists under the structural damping ratios of 1%. Crash barrier and maintenance way railings with cylinder shape are conducive to decrease VIV amplitude, both vertical and torsional. The VIV can be mitigated via sharpening wind fairings and the vibration mitigation effect is more significant with the smaller wind fairing angle. The horizontal flow-isolating plate (HFIP), jutting out of the inner edge of the girder bottom plates, can mitigate and even eliminate the VIV effectively. Generally, within certain limits, the wider the HFIP is, the better the mitigation effect.