桥塔风效应对异形斜拉桥抖振响应的影响

Influence of tower wind effect on buffeting response of special-shaped cable-stayed bridge

异形斜拉桥桥塔刚度小,受力情况复杂,主梁和桥塔的气动耦合现象强。目前关于桥塔风效应对桥梁风致抖振响应的研究大多是基于普通多塔斜拉桥和悬索桥的,针对异形斜拉桥桥塔风效应的影响鲜有研究。分别利用风洞试验及数值模拟的方法得到了某异形斜拉桥主梁及桥塔截面的三分力系数,以及主梁、桥塔的脉动风速时程,并基于准定常理论得到气动自激力的时域化模型。在此基础上,分别研究了自激力及桥塔风效应对该桥抖振响应的影响。研究表明:主梁竖向位移受桥塔风效应影响较小,但桥塔横向位移响应及主梁横向、扭转位移响应受桥塔风效应影响较大,且桥塔横向位移响应增大幅度较为明显;自激力会使该桥主梁位移响应略微减小,但影响很小。

The towers of special-shaped cable-stayed bridges have low stiffness and complex stress conditions,with strong aerodynamic coupling phenomena between the girder and the towers.Current research on the impact of wind effects on bridge buffeting responses primarily focused on conventional multi-tower cable-stayed bridges and suspension bridges,with few studies addressing the wind effects on towers of special-shaped cable-stayed bridges.In this paper,wind tunnel experiments and numerical simulations were used to obtain three-component coefficients of the girder and tower sections of a special-shaped cable-stayed bridge,as well as the fluctuating wind speed time histories.Based on the quasi-steady theory,a time-domain model of the aerodynamic self-excited forces was developed.On this basis,the influences of self-excited forces and wind effects on the buffeting response of the bridge were studied separately.The results indicate that the vertical displacement of the girder is minimally affected by the wind effects on the towers,while the lateral displacement response of the towers and the lateral and torsional displacement responses of the girder are significantly influenced by the wind effects,with a noticeable increase in the lateral displacement response.Additionally,the self-excited forces slightly reduce the displacement response of the girder,but the impact is minimal.