考虑风速空间分布的三塔悬索桥静风稳定分析

Aerostatic stability analysis of suspension bridge with three towers considering spatial distribution of wind speed

为了研究平均风速空间分布对大跨桥梁静风稳定性的影响,将风速空间分布系数引入到大跨桥梁静风稳定性计算中,建立了考虑风速空间分布的静风稳定分析方法.以马鞍山大桥为算例,分析了平均风沿展向的不均匀分布对三塔悬索桥静风失稳临界风速和失稳形态的影响.结果表明:风速非对称分布且风速最大值位于任一跨跨中时的静风失稳临界风速最低.风速非对称分布时,低风速下两跨扭转位移和竖向位移的变化趋势类似,随着风速增长,风速较大的一跨变形加剧,由于主缆的牵扯作用,另一跨只能以相反的趋势变化.风速空间分布对三塔悬索桥静风稳定具有较大影响,不可忽略.

To study the effects of the spatial distribution of the average wind speed on the aerostatic stability of long-span bridges,the aerostatic stability analysis method considering the spatial distribution of the wind speed was put forw ard by introducing the wind speed spatial distribution coefficient.By taking the M aanshan Bridge as an example,the effects of the wind speed spatial non-uniformity along the deck on the critical wind speed and the aerostatic instability configuration were analyzed.The results show that the critical wind speed of the aerostatic instability is the lowest when the wind speed is asymmetrically distributed and the maximum wind speed is at the one of the two midspans.When the wind speed is asymmetrically distributed,the torsional and the vertical displacements at the lower wind speeds exhibit the same change tendency. How ever,the deformations of the span with the higher wind speeds intensify with the increase of the wind speed,and those of the other span change with the opposite trend due to the dragging influence of the main cables. The spatial distribution of the wind speed has a considerable and non-negligible effect on the aerostatic stability of suspension bridges with three towers.