钢桥塔涡振气动控制措施研究

Aerodynamic mitigation measures for vortex-induced vibration of steel tower

杭州之江大桥桥塔为曲线型钢桥塔,刚度与阻尼较小,桥塔自立状态出现涡振的可能性较大。为确定桥塔的涡振风速锁定区间及涡振振幅,进行了全塔气弹模型试验。试验结果显示,在横桥向来流的作用下,桥塔顺桥向涡振振幅过大,需要采取气动控制措施加以控制。试验中所采用的气动措施包括:在桥塔凹角处增加扰流栏杆、多孔角型扰流器和多孔扰流板等控制措施。进一步的试验结果显示,多孔扰流板的涡振控制效果显著,能有效降低涡振振幅,满足规范的限值要求。多孔扰流板的减振机理是其允许适量的气流穿过其孔洞,从而扰乱或削弱桥塔两侧角部有规律的旋涡脱落。

The tower of Hangzhou Zhijiang Bridge is a curved steel tower with lower stiffness and damping.Its free-standing construction state is thus liable to vortexinduced vibration.An aeroelastic model test of full tower was carried out to determine the vibration amplitude and the corresponding lock-in range of wind speed.The test results show that the amplitude of the longitudinal vortex-induced vibration is excessive and needs to reduce through proper aerodynamic measures.The aerodynamic measures investigated in this paper include： flow-disturbing rail,multi-orifice angle-shape flow disturbers and multi-orifice flow-disturging plates mounted at the corners of the tower model.The further tests indicate that the measure of multi-orifice flow-disturbing plates is very effective in decreasing the amplitude of vortex-induced vibration to meet the relevant requirement of the wind resistant code.The mechanism of vibration reduction of the multi-orifice flow-disturbing plates is that the plates can disorder or weaken the regular vortices shedding at the tower corners via allowing some appropriate quantity of air flow passing their orifices.