施工中大桥桥塔的TMD减振研究

施工中大桥桥塔的风致振动对施工具有很大的危害,采用调谐质量阻尼器(TMD)对其进行减振。首先,通过一个二自由度的振动模型来阐述TMD装置的工作原理,并导出了TMD参数和外激励频率与减振效果的之间的关系。然后,在讨论大桥桥塔结构按一阶模态向一个单自由度系统的等效简化问题中,提出了一种基于固有频率的等效质量简便算法。最后,结合崖门大桥的桥塔施工进行实例TMD减振分析, 实测结果表明TMD的减振效果非常好但其设计过程也很复杂。

REDUCTION OF VIBRATION DURING CONSTRUCTION OF BRIDGE TOWERS BY TMD

The wind-induced vibration of the bridge towers is detrimental to the safety of construction. In this paper, the Tuned Mass Damper (TMD) is used to reduce the wind-induced vibration. First, a vibration model of two freedom degrees is introduced to describe the mechanism of TMD by the relation of the vibration amplitude to both the parameters of TMD and the frequency of exterior excitation. Secondly, a simple method, which is based on the first eigen-frequency, is designed to compute the equivalent mass of the tower according to its first mode. A practical example about reduction of vibration of the large cable-stayed Yamen bridge is presented. It is demonstrated that the reduction of vibration by TMD to the tower of bridge is very effective despite the complicity involved in the design process.