土-结构相互作用1:4钢框架-筏板基础模型激振试验研究

Experimental Investigation of Soil-structure Interaction on the Excitation Test of 1:4 Scaled Steel Frame-raft Foundation Model

为了了解土与结构的相互作用,在土槽中进行1∶4钢框架的激振试验,试验通过改变上部结构刚度,分别输入高斯白噪声测自振周期,EL波和Taft波研究其动力反应及土体对上部结构的减震效果,与有限元软件SAP2000模拟刚性地基上的钢框架做动力反应分析对比,发现自振周期有一定差异,上部结构刚度越大附加周期越大,附加周期最大值达到0.22 s。土体对钢框架有一定的减震效果,这种减震效果主要跟上部结构刚度变化有关,由于土-结构相互作用,钢框架在土槽中激振时顶层加速度峰值比在刚性地基上激振时减小,折减系数达0.661,而顶层位移峰值则增大。

In order to understand the soil-structure interaction, the excitation test of 1：4 scaled steel frame-raft foundation model was carried out in the soil bin. By changing the stiffness of the superstructure, Gaussian white noise was inputted to measure vibration peri- od, EL wave and Taft wave was inputted to known dynamic response and the shock absorption effected about the soil to the upper struc- ture,the finite element software SAP2000 was used to simulate the steel frame-raft on rigid foundation, and then the dynamic response was analyzed. The results showed that the greater the additional period the upper part of the greater structural stiffness. The maximum of the additional period reaches 0.22 s. The soil has shock absorbing effect to the steel frame, and the effect is mainly with the change of structure stiffness. Because of the soil-structure interaction, the peak acceleration of the top storey is reduced while the steel framework is excited in the soil bin than on rigid foundation, the reduction factor is reached 0.661, and the peak displacement of the top storey is increased.