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基于Harichandran-Vanmarcke相干函数模型和改进的Kanai-Tajimi过滤白噪声自谱模型,以及Amin-Ang非平稳化函数模型,采用MATLAB语言程序,引入快速傅里叶变换(FFT)算法,编制了基于Geodatis改进型谱表示法的考虑地震动空间变异性的非平稳人工加速度时程。分别采用线性加速度积分法和FFT变换频域积分法将加速度时程转化为位移时程作为地震动激励。运用双线性恢复力模型,引入ANSYS中的COMBIN40单元来模拟双肢薄壁墩墩顶、墩底塑性铰截面的材料非线性关系,同时,考虑桥墩大位移而导致的几何非线性,建立桥梁结构双重非线性有限元模型,得出高墩连续刚构桥在罕遇地震作用下的非线性受力特性和塑性铰截面的延性特性。其分析方法和结果对同类桥梁结构在罕遇地震动激励下的抗震设计与研究具有一定的参考价值。
Based on the Harichandran-Vanmarcke coherence function model and the improved Kanai-Tajimi filtered white noise auto-spectral model and the Amin-Ang non-stationary function model, a MATLAB language program was introduced to introduce the Fast Fourier Transform (FFT) Nonstationary Artificial Accelerometer Time Series Considering Spatial Variability of Earthquake Ground Based on Improved Spectral Representation. The acceleration time history is transformed into the displacement time history using the linear acceleration integral method and the FFT frequency-domain integral method respectively as the earthquake excitation. By using the bilinear restoring force model, COMBIN40 element in ANSYS is introduced to simulate the material nonlinearity of the plastic hinge at the top and bottom of thin-walled piers with double limbs. At the same time, considering the geometric nonlinearity caused by the large displacement of bridge pier, a bridge is established The results show that the nonlinear behavior of high rigid continuous rigid frame bridge under rare earthquakes and the ductility of plastic hinge section are obtained. The analysis methods and results have certain reference value for the aseismic design and research of similar bridge structures under the rare earthquake excitation.