【摘要】 介绍了室内土槽中1∶4钢框架模型的低频激振试验,利用激振器输出地震波激振钢框架模型,拾振器测量楼层加速度和位移响应,通过频谱分析测得模型的基频和自振周期,求得减震系数。采用SAP 2000对刚性地基上模型输入与试验相同的地震波,计算出模型的基频、自振周期、顶层加速度峰值和顶层位移峰值,并与试验值进行对比。结果表明,考虑土-结构相互作用后,结构的自振周期均有所延长,刚度相同、楼层质量大的模型周期延长比较大,顶层位移峰值增大,加速度峰值减小。绘制出位移放大系数和加速度折减系数随结构刚度的变化曲线,对位移放大系数和加速度折减系数随结构槡k/m的变化规律进行拟合,得到可供工程抗震设计参考的拟合曲线。更多还原

【Abstract】 Low-frequency excitation experiment of a 1:4 scaled steel frame model was performed in an indoor soil bin.Using an exciter which can output different seismic waves to excite the steel frame,vibration picking devices were used to measure the acceleration and displacement responses of floors.By spectral analysis the fundamental frequency and natural period of the model were obtained,and the shock absorption coefficient was calculated.Using SAP2000 to simulate the model on rigid foundation,the same seismic waves were input on the model to calculate the fundamental frequency,natural period,peak acceleration and displacement of the top floor of the model.Compared with the results of experiment,several conclusions are drawn.After considering soil-structure interaction,natural period of the model is elongated.With the same stiffness,the greater the mass of the floor is,the more obvious the elongation effect is.The peak displacement of top floor increases,while the peak acceleration decreases.Curves of displacement amplification and acceleration reduction coefficients versus structural stiffness were drawn.It is found that the displacement amplification and acceleration reduction coefficients vary in accordance with k/m,which can be defined by two fitted curves obtained by regression analysis.The curves can be referred in practical seismic design.更多还原