南水北调丹江口加高工程施工栈桥结构模态分析

振动模态分析是桥梁结构设计的重要步骤。利用大型有限元软件ANSYS,对南水北调丹江口大坝加高工程38号-25号坝后架设的临时施工运输栈桥结构进行模态分析,计算了栈桥结构的前八阶固有频率与主振型。研究认为,当受到外部激励的频率与固有频率接近时,有可能产生共振,从而严重损害栈桥结构;栈桥第4、5、6、8跨是其薄弱环节,使用过程中应避免同频率的车辆在上面停留。研究结果为栈桥结构的动力学设计提供了重要依据,也可为其他同类型的结构设计提供参考。

Modal Analysis of Construction Trestle Structure of Danjiangkou Heightening Project in the South-to-North Water Diversion Project

Vibration modal analysis is essential for the design of construction trestle. The modal analysis was performed on the temporary construction transportation trestle behind the 38 # ~ 25 # dam of the Danjiangkou dam heightening project in the South-to-North Water Diversion Project using the finite element analysis software ANSYS, and the natural frequencies and principal vibration modes for the first 8-order modals were determined. The results showed that the construction trestle might resonate when the frequencies of external drive are close to the natural frequencies of the construction trestle, which can cause serious damage to the structure of construction trestle. Moreover, the fourth, fifth, sixth, and eighth strides were weaker than other strides, therefore the stay of the cars with similar frequencies should be avoided. The results can provide significant basis for the dynamic design of trestle structure and the design of other structures.