大跨隔震结构竖向非线性反应谱

Vertical nonlinear response spectrum of long-span isolated structure

提出大跨隔震结构的简化计算模型,推导了大跨隔震结构在多点激励和一致激励下竖向运动控制方程;基于该简化模型,建立大跨屋盖的竖向加速度非线性反应谱,并与规范反应谱进行比较,研究多点激励对竖向非线性响应的影响规律;最后,与两层大跨隔震结构缩尺模型的振动台试验结果进行对比,验证竖向非线性反应谱的准确性。结果表明:多点激励对竖向非线性反应谱影响比较明显,对结构的影响随周期的增大而减小,随跨度的增大而增大;当采用规范反应谱曲线对大跨隔震结构进行抗震设计时,结果存在较大偏差,而新建竖向非线性反应谱进行抗震设计时,得到的结果比用规范谱计算得到的结果更接近真实值。

A simplified model for long-span isolated structure was proposed.The vertical motion equation of long-span isolated structure under multi-support excitations and uniform excitation were derived.Based on the simplified model,nonlinear response spectra of vertical acceleration were established and compared with seismic design code response spectra.The influence of multi-point excitations on vertical nonlinear response was analyzed,and the accuracy of nonlinear response spectrum was verified with the shaking table test on two layer model of large-span isolated structure.Results indicated multi-point excitations had significant influence on vertical nonlinear response spectra,and the influence decreased with the increase of structure period while increased with the increase of span.It had a large deviation if performing the seismic design of long-span isolated structure according to code response spectrum.The calculated vertical nonlinear response spectra established were in good agreements with the experimental ones.