斜拉桥拉索雨风振机理探讨

MECHANISM OF RAIN-WIND-INDUCED VIBRATIONS OF CABLES IN CABLE-STAYED BRIDGES

斜拉桥拉索在雨和风联合作用的特定条件下,会产生大幅强烈的振动。其振动机理引起了人们极大关注。将风场中带水线的拉索简化为二维含水线影响的拉索绕流问题进行了流场分析。通过计算得到了拉索的气动载荷,根据这些气动载荷,采用水线相对拉索运动和不运动的两种简化模型进行了拉索的振动分析,结果表明雨风振是涡振和驰振耦合作用的结果。

Under combined actions of both wind and rain, the cables in cable-stayed bridges would vibrate very extensively and strongly. The mechanism of the rain-wind-induced vibrations has received great concerns. The fluid field around a cable with a water-line was simplified into a 2-D flow over the cable section problem to compute the aerodynamic loadings. With these loadings, two simplified vibration models of the cable and the water line, were adopted to study the stability of motions of the cable and the water-line. Computational results show that the rain-wind-induced vibrations are due to the coupling action of vortex-induced vibrations and galloping vibrations of wake.