独柱式变截面倾斜桥塔气动特性风洞试验研究

Wind tunnel test on aerodynamic characteristics of inclined single-column pylons with variable cross section

独柱式桥塔易发生风致振动,当塔柱倾斜且采用变截面形式时,风的作用下常表现出复杂的三维流动效应。为考察独柱式变截面斜塔静动力气动性能,通过桥塔刚性模型测力风洞试验测试了不同风向角下桥塔气动力系数,对比分析了桥塔三维绕流的影响。通过桥塔气弹模型测振风洞试验,测试了涡激振动起振风速及振幅,对比了来流风向及阻尼比对桥塔涡激振动的影响。研究结果表明,桥塔整体气动力系数及断面等效气动力系数沿塔高的变化规律受来流风向角的影响显著,顺桥向风作用下倾斜桥塔易发生横桥向涡激振动,提高结构阻尼比,可有效抑制涡振。

The inclined single-column pylon with variable cross section of a cable stayed bridge, usually exhibiting complicated spatial ambient flow in the atmospheric field is prone to vi brate. In order to investigate the static aerodynamic performance, the rigid model test in wind tunnel was carried out to study the aerodynamic coefficients under different wind yaw angles, and spatial ambient flow effect on the pylon was analysed. The oscillatory velocities and amplitudes under different damping ratios and different wind yaw angles were tested and compared by the aeroelastic model test. The research results indicate that the integral coefficients and equivalent section aerodynamic coefficients were influenced by spatial ambient flow remarkably and the in clined pylon suffers notable lateral vortex-induced resonances within the longitudinal wind. In- creasing the damping ratio in transverse direction will be helpful to the vibration resistance.