考虑土与结构相互作用的钢筋混凝土框架子结构抗震性能试验研究

Experimental research on seismic behavior of reinforced concrete frame substructure considering soil-structure interaction

独立基础-钢筋混凝土框架结构在遭遇地震时会出现底层柱破坏严重并且柱端出现大量塑性铰的破坏形态,同时考虑到独立基础对底层柱的约束能力会影响上部结构塑性铰的发展顺序,应对土与结构相互作用对混凝土框架抗震性能的影响进行研究。为此,对一榀独立基础-框架子结构开展低周反复荷载试验,分析考虑土与结构相互作用下结构的抗震性能。结果表明:独立基础-框架子结构具有良好的耗能能力和延性;结构屈服机制为梁铰机制,整个试验过程中结构刚度退化明显,刚度退化主要发生在结构屈服之前;中柱和边柱柱下独立基础最大转角分别为1/60和1/80,基础基底反力近似呈直线分布。

In the earthquake disaster area, several columns at the bottom floors of the independent foundation-reinforced concrete frames were severely damaged and a large number of plastic hinges appeared at the end of the column. The restraint capacity of the independent foundation on the bottom column will affect the development order of plastic hinges in the upper structure. Therefore, to study the effect of soil-structure interaction on the seismic performance of the concrete frame, low cyclic reversed loading tests on an independent foundation-frame substructure were carried out, and the seismic performance of structure considering the effect of foundation soil was analyzed. The test results show that the independent foundation-frame substructure has good energy dissipation and ductility. The yielding mechanism of the structure is beam hinge yield mechanism. The stiffness degradation of the structure is obvious during the whole test process, and the stiffness degradation mainly occurs before the structure yields. The maximum rotation angles of the independent foundation under the central column and the side column are 1/60 and 1/80, respectively, and the contact pressure of the foundation basement is approximate linear distribution.