斜交高墩大跨度连续箱梁桥动力特性及其颤振分析

Analysis of dynamic characteristics and flutter for large span continuous box girder bridge with high skew piers

以湖南省张花高速公路酉水大桥(80+145+80)m斜交高墩大跨度悬臂浇筑预应力混凝土连续箱梁桥为工程背景,运用有限元方法分析斜交高墩大跨度连续箱梁桥在最高墩施工阶段、最大悬臂施工阶段以及成桥阶段的动力特性,对比HBM动力测试仪现场测试的自振特性,对桥梁结构的刚度进行评价;计算桥梁结构的颤振临界风速,分析桥梁在自然风作用下的颤振稳定性。研究结果表明:桥梁在3个施工阶段纵向刚度最小,最大悬臂施工阶段扭转刚度最小,为自然风颤振最不利阶段,其颤振临界风速大于颤振检验风速,桥梁结构颤振稳定。

On the background of Youshui bridge, a 80 m plus 145 m plus 80 m prestressed large span continuous box girder continuous bridge with high skew piers, constructed with cantilever method on Zhanghua highway Hunan province, dynamic characteristics of large span continuous box girder bridge with skew piers were analyzed by using the finite element method in the construction stage of the highest pier, the largest cantilever and the formation of overall bridge, and vibration characteristics were compared with that by the HBM dynamic test on field. The stiffness of bridge structure was evaluated and the critical flutter speed of bridge structure was calculated. Meanwhile, the flutter stability of the bridge was investigated under the action of natural wind. The results show that the longitudinal stiffness of the bridge is the smallest in the three stages of construction, and the torsional stiffness of the bridge is the smallest in the stage of the largest cantilever, which is the most unfavorable stage under the action of natural wind. When the critical the bridge structure would remain stable. flutter speed is greater than the checking flutter speed,