基于二维相干性自锚悬索桥非一致激励地震响应分析

Analysis of Seismic Responses with Non-uniform Excitations of Self-anchored Suspension Bridge Based on a 2D-coherence Model

一般在非一致地震激励的模拟中采用一维相干模型,即模型中只含有沿地震波传播方向的变量,当垂直于地震波传播方向两点距离较远(如横桥向),则支点间的相干性对地震响应有一定影响.基于二维相干模型,应用三角级数法,考虑频率对视波速的影响、地震波传播滞后对非平稳调制函数的影响,生成某自锚式悬索桥各支点的人工地震波.利用该地震波,应用大质量法对自锚式悬索桥非线性地震响应进行时程分析,分别考虑几何非线性、材料非线性的影响,研究不同激励作用下结构的响应,并与基于一维相干的地震响应结果进行了对比,从中得到一些有意义的结论.

Usually a seismic excitation, including only one variation which travels along a seismic wave motion, is simulated on a 1Dcoherence model. However, when two excitation points have a distance in between （e. g. a lateral bridge）, which are vertical to the seismic wave, they influence each other. Based on a 2D-coherence model, this paper, employing the method of triangular series, analyzes the effect of frequency on wave velocity, the effect of seismic wave lag on non-uniformly modulation and the function to simulate artificial seismic waves at the very support of a self-anchored suspension. With the help of these waves, the paper, considering geometric and material nonlinear influences and using the great mass method, analyzes the seismic time-history responses of the self-anchored suspension bridge and explores its different responses under different excitations. After a comparison with the results on the 1D-coherence model, it finally obtains some valuable conclusions.