Experimental Research On Seismic Behavior Of Concrete-Filled Square Steel Tubular Repaired Frame

As the development of constructional material and technology, the structure of concrete-filled square steel tubular (CFST) column has been increasingly popular in high-rise or super high-rise structures. So far, the majority of research concentrates on the aspects of beam, column and joint, and there are few researches on the frame consisted with CFST columns and steel beams. Moreover, it is easy to appear the crack for the joints of concrete-filled steel tubular frame. There are lots of methods strengthening and repairing the damaged joints, but it is necessary to validate them through some experiments. Base on the above two points, the experiment was done.The primary frame is a two-lay, three-story model of concrete-filled square steel tubular frame, which has no initial damage. In the first experiment, it was damaged under low-cycle reversed loading. Then the damaged frame was been repaired in this experiment, and the seismic behavior of the repaired frame was investigated experimentally under low-cycle reversed loading, including the hysteretic behavior, the failure characteristics, the ductility characteristics and so on, which may be referred for practical design and investigation. Based on the experimental results, the two conclusions could be generally drawn. The first one is the repaired frame still has good seismic behavior. The second one is that the design of strengthening and repairing is feasible because the seismic behavior of the repaired frame is better than the primary one, such as bearing capacity, deformation, the hysteretic behavior, dissipation capacity and so on.In addition, the finite element analysis was done to simulate the experiment, and the simulative curve of the hysteretic behavior was given. The curve indicates the analytical results generally tally with the experimental ones.