Experimental and numerical research of the steel frames with replaceable column foot

Abstract

For steel moment-resisting frames, the plastic hinge often occurs in column foot under the action of earthquakes and it is difficult to repair the column foot developed plastic. To avoid the damage concentration effect of column foot, the innovative replaceable column foot is proposed in this paper, which can protect the column on the bottom floor and reduce the residual drifts of column. The stiffness and deformation of the replaceable column foot were investigated and compared with conventional rigid column foot. The pseudo-static test program of a one-third scaled steel frame with the replaceable column foot was carried out. The design approaches were recommended and verified based on the test results. The residual drifts, ductility and load-bearing capacity of the steel frame with replaceable column foot were investigated by finite element analysis and the results were compared to the steel frame with rigid column foot. It was found that the replaceable column foot can reduce the damage concentration effect of column on the bottom floor and the plastic deformations of replaceable column foot were mainly concentrated in energy dissipating components as expected. The residual drifts of the steel frame with replaceable column foot are less than that of the structure with rigid column foot. The parametric analysis of the replaceable column foot with different values of rational stiffness was performed. The results showed that the residual drifts, initial stiffness and load-bearing capacity of replaceable column foot can be accurately evaluated by the proposed design approaches. By the rational design of rational stiffness of replaceable column foot, different levels of stiffness and load-bearing capacity demand can be satisfied.