Vibration Test for Frame Structure of Concrete-Filled Square Steel Tubular Column

This paper presents the results of experimental research on the dynamic behavior of a frame structure consisting of a concrete-filled square tubular steel column. It is said that the concrete-filled Square column, the so-called composite column, possesses good strength and ideal ductility. However, its characteristic of vibration under strong earthquakes is not clear enough at present. We conducted experiments to compare the effect of the composite frame with that of the noncomposite frame using a shaking table. In these experiments the following were observed. The composite structure was superior to the noncomposite one in terms of stiffness. The damping ratio increased remarkably outside of the elastic domain.