| Local bucling of H-shape steel columns caused by earthquake loading often causes bearing capacity falls down quickly in the monment-resisting frame. In order to solve this problem, Professor Xiao proposed an additional confinement. It can prevent or delay the inelastic buckling of H-shape steel columns at the potential plastic zones. Bearing capacity of H-shape steel columns falls down slowly because confinement prevents or delays the inelastic buckling of H-shape steel column. Expermental study of steel hoop confined H-shape steel columns indicated confined H-shape steel columns exhibited improved seismic performance with ductility compared with conventional H-shape steel columns. In this paper, experiment of RC confined H-shape steel columns is carried out under constant axial load and cyclic lateral forces. Confinement was made of the concrete block filled in flange girth and reinforcement hoop. The main work is summarized as follows:(1) State of art about the characteristics and application of hot-rolled H-shape steel is given. We also review the experimental and analytical research work of hot-rolled H-shape and steel columns.(2) Four large-scale H-shape steel columns were designed to simulate typical columns in multi-story building in seismic regions. The four columns were devided into two groups, in which three were for strong axis bending and one was for weak axis bending.(3) All confined columns were tested under constant axial load and cyclic lateral forces. The failure mode, strength degradation, stiffness degradation, ductility and energy dissipation were reported to investigate the seismic behavior of RC confined columns. Comapred with the conventional H-shape steel comumns, the confined ones exhibited significantly improved seismic performance with large ducility. At the same time, the paper reported different character of RC and steel hoop confined columns.(4) The paper proposed the mode of stress-strain of steel with confinement. We calculated the detail of moment-curve and load-displacement, and discussed the mechanics of confined H-shape steel columns. |
