超长斜拉索风阻系数及风雨激振的试验研究

结合主跨为1088m的世界最大跨度斜拉桥苏通大桥,对拉索的抗风问题进行了系统的研究。通过横桥向、顺桥向拉索风阻系数的风洞测量试验,得到了光索、螺旋线及压痕凹坑3种表面情况拉索的风阻系数;并模拟人工降雨,在风洞中重现了拉索的风雨激振现象,研究了风速、降雨量、拉索表面情况以及机械阻尼对风雨激振的影响。结果表明,拉索的阻力系数与表面情况、倾角、Re数密切相关,螺旋线、压痕凹坑及机械阻尼均可有效抑制拉索风雨激振现象。本文的试验方法及结果为超长斜拉索抗风研究提供了有益的参考。

Investigation on Drag Coefficients and Rain-Wind Induced Vibration of Extremely Long Stay Cables in Wind Tunnel

Wind tunnel tests of drag coefficients and rain-wind induced vibration of stay cables were carried out in this paper. Smooth cables, cables with helical wires, and dimpled surface cables were investigated in the tests. The test results were applied to Sutong Bridge with a main span 1 088 m long. The drag coefficients of wind perpendicular to bridge axis and wind along bridge axis of cables obtained from tests were functions of surface processing, inclination angle, and Re number. The phenomenon of rain-wind induced vibration of cable models was then re-produced under the condition of simulation of rain and wind. Through the tests, the effects of some parameters, such as wind velocity, rain intensity, surface processing, and mechanical damper, on the rain-wind induced vibration were studied. The test results showed that cables with helical wires, dimpled surface cables, and mechanical damper could effectively mitigate the rain-wind induced vibration.