斜拉桥拉索风雨激振的试验研究

Experimental Study on Rain-wind Induced Vibration of Cables in Cable-stayed Bridge

风雨激振现象是斜拉桥拉索在风雨共同作用下经常发生的一种激烈的大幅振动,危害性很大,涉及固、液、气三态,情况复杂.为了揭示风雨激振的一些内在规律,进行了人工降雨雨振试验和人工水线雨振试验.通过人工降雨雨振试验,再现了拉索风雨激振现象,通过人工水线雨振试验,研究了水线的大小和位置、斜拉索动力参数及偏转角等对风雨激振的影响.试验结果表明:在拉索表面形成一定大小的上水线是拉索发生风雨激振的必要条件,且上水线要在拉索表面特定的范围内形成;增大阻尼和自振频率可有效减小拉索的风雨激振振幅;拉索的风雨激振现象只能发生在一个特定的偏转角范围内.

Rain-wind-induced vibration is a destructive large-amplitude vibration,which often occurs under the combined influence of wind and rain.Rain-wind-induced vibration is a very complex phenomenon concerned with rain,wind,and cable,and its mechanism is not well explained yet.In this paper,the rain-wind-induced vibration tests with artificial rain or artificial upper rivulet are carried out to clarify the mechanism of rain-wind-induced vibration.The phenomenon of rain-wind-induced vibration of a cable model is re-produced under condition of simulation of rain and wind.A cable model with artificial upper rivulet has also been tested,and the effects of some parameters,such as the size and position of rivulet,the dynamic parameters of cable model,and wind yaw angle etc.,on the rain-wind-induced vibration are experimentally investigated.The results show that the upper rivulet which must be larger than a threshold and on some scope of the cable surface seem the prerequisite for the appearance of rain-wind-induced vibration of the cable,and that vibration amplitude of rain-wind-induced vibration will decrease obviously with the increase of frequency and damping of a cable,and that cables are susceptible to rain-wind-induced vibration at wind angles between 0° and 30°.