大跨钢箱梁悬索桥地震响应有限元分析

根据某大跨钢箱梁悬索桥的设计图纸,采用ANSYS建立其有限元模型,采用壳单元对主梁进行模拟.通过不断调试找出最佳的主缆初始应力,完成悬索桥的初始找形分析.对悬索桥进行预应力模态分析,采用瑞利阻尼理论,通过悬索桥有限元模型的前2阶圆频率计算模型的质量阻尼和刚度阻尼.采用动力时程分析法对悬索桥进行地震响应有限元分析.结果表明:横桥向位移的最大峰值由横桥向地震波输入决定,纵桥向位移的最大峰值以及竖桥向位移的最大峰值主要由重力载荷工况决定,地震载荷工况对其贡献非常小.

Finite element analysis on seismic response of large-span steel box girder suspension bridge

Based on a large-span steel box girder suspension bridge as the background, firstly, according to the design drawings of suspension bridge, use the general finite element software ANSYS to build the finite element model of suspension bridge which girder is simulated by shell elements. Secondly, through continuous debugging, find out the best initial stress of the main cables, to complete the initial form-finding analysis of suspension Bridges. Again, do prestressed modal analysis of suspension bridge. Using the Rayleigh damping theory, calculate the mass damping and the stiffness damping of the model through the first two order circular frequency of the finite element model of suspension bridge. Finally, use the dynamic time history analysis method to calculate the seismic responses finite element analysis of the suspension bridge. The results show that, the maximal peak value of displacement in the transverse direction of bridge is determined by the seismic load input in the transverse direction of bridge, the maximal peak value of displacement in the longitudinal direction of the bridge and the maximal peak value of displacement in the vertical direction of the bridge are determined by the gravity load, to which the seismic load input makes a little contribution.