茅草街大桥主桥的地震反应分析

以湖南茅草街大桥为研究对象,采用大型有限元分析软件ANSYS建立了该钢管混凝土系杆拱桥的三维有限元模型并对其进行模态分析,在此基础上运用反应谱法计算了该桥的纵向、横向和竖向地震响应,探讨了主要结构参数对中承式钢管混凝土系杆拱桥地震响应的影响,可为大跨钢管混凝土拱桥的抗震设计提供理论参考。

Seismic Response Spectrum Analysis of Maocaojie Bridge

Maochaojie Bridge with a main span of 368 m is a concrete filled steel tubular arc bridge. In this paper, a 3 dimensional model for the bridge is established. Based on the model and the dynamical equation of MDOF structural system, model analysis and seismic response spectrum analysis are carried out by use of CQC, a vibration combination method and SRSS, a space combination method. The effects of primary structural factors on seismic response is studied. Analytical results are as follows: 1.The maximum seismic stress of the concrete filled steel tubular arc bridge appears in arc buttress; 2.If in plane effect is considered only, the structure order is affected lesser by transverse earthquake input. But because the first order vibration shape is the main arc and the bridge deck crosses the bridge symmetrically, the out plane effect by transverse earthquake input is very important to the structure and should not be neglected in bridge design; 3.The structure is also influenced greatly by vertical earthquake input. Moreover, seismic stress in some parts of the bridge is dominated by this kind of earthquake input, to which attention should be paid in bridge design; 4.Compared with other load conditions, the seismic stress is smaller and does not dominate the bridge design; The results obtained in this paper possess reference values for seismic resistance design of large span concrete filled steel tubular arc bridge.