开口截面斜拉桥涡激共振风洞试验及减振措施研究

对某大跨开口截面斜拉桥进行节段模型风洞试验,测试了主梁成桥状态的气动性能.试验结果表明,该桥主梁在设计风速范围内出现了明显的竖弯以及扭转涡激共振现象.参数化的试验研究表明,该桥的涡激共振现象在相当广泛的阻尼比范围内均存在,即使将竖弯以及扭转阻尼比提高到1%以上仍然存在明显的涡激共振现象,且振动幅值仍超过规范允许值.为了抑制主梁的涡激共振,通过风洞试验设计了有效的气动措施减振方案.测试表明,所采用的减振措施能有效地消除该桥涡激共振的发生.

Vortex-induced Vibration and Control Method for a Cable-stayed Bridge with Open Cross Section

The aerodynamic performances of a long-span cable-stayed bridge in its completion state, which has a deck girder of open cross section, were investigated with sectional model tests in wind tunnel. Experiment results have shown that the deck of the bridge concerned suffers remarkable vortex-induced resonances within the designed wind velocity, both vertical and torsional. Parametric experiment study has shown that this vortex-induced resonance exists in an extensive scope of structural damping ratios, with amplitudes overstepping the permitted value based on recognized standard even if both the vertical and torsional damping ratios of the section model increase up to 1%. In order to suppress the vortex-induced deck oscillation, an effective vibration control scheme has been brought forward in virtue of wind tunnel tests. Model tests have shown that the adopted mitigation measure can eliminate the vortex-induced resonance effectively. Aerodynamic measure put forward will be helpful to the wind-resistance design of analogous bridges.