地震动频谱特性对隔震结构非线性地震响应的影响

Effects of nonlinear seismic response of isolated structures on spectrum characteristics of ground motions

采用等效线性化方法建立隔震结构不同周期的单质点分析模型,用加速度反应谱平均周期(Tr)表征地震动频谱特性,对不同特性的隔震结构输入Tr在0.3～5.5 s的地震波,研究这些不同频谱特性地震波对不同周期以及不同屈重比隔震结构的影响。结果表明:当隔震周期大于4.0 s时,上部结构的加速度和隔震层位移随着Tr的增大而增大。当隔震周期小于4.0 s时,上部结构的加速度和隔震层位移随着Tr的增大先增大后减小。随着Tr的增大,上部结构加速度先随着屈重比的增大而增大,一定范围后,随着屈重比的增大而减小,隔震层的位移随着屈重比的增大而减小。地震动的频谱特性对隔震结构的减震效果影响很大,但隔震结构周期为4.0 s左右时可以取得最佳的减震效果。

The equivalent linear design method was used based on the single degree of freedom （ SDOF system for isolated building with different periods. Acceleration average response spectral period （ Tr） was used to characterize the spectrum characteristics of ground motions. Seismic waves with different periods were input to the isolated structures to obtain the effects on the isolated structures with different periods and different flexion weight ratios. Studies showed that when the period of isolated structures was greater than 4.0 s, the acceleration of the super-structure and the isolation layer displacement increased with the increasing of Tr. When the period of isolated structures was less than 4.0 s, the acceleration of the super- structure and the isolation layer displacement firstly increased, and then decreased with the increasing of Tr. With the increasing of Tr, the acceleration of the superstructure firstly increased with the increasing of flexion weight ratio, then the acceleration of the superstructure reduced with the increasing of flexion weight ratio. The isolation layer displacement reduced with the increasing of flexion weight ratio. The spectral characteristics of ground motions had a great influence on damping effect of the isolated structure, but it obtained the best damping effect when the isolated structure period was 4. 0 s.