Research On Behavior Of Concrete-filled Rectangular Steel Tubular Columns Under Cyclical Loading

In recent years, as the architectural technical developments, the concrete-filled steel structures has gradually been applied in the architectural structure especially in the high buildings. Compared with the circular concrete-filled steel tubular, concrete-filled rectangular steel tubular have some advantages: easier to connect with beams; better stability; and the low cost of fire prevention etc. Compared with the solid concrete-filled rectangular steel tubular(SCFRST); Concrete filled rectangular double skin steel Tubes (CFDRST) have some advantages:easier to connect with beams; ethereal of deadweight; and the low cost of fire prevention etc.But few research studies have been dealt with in this area in the past,so the study of it possesses important theoretic and engineering reference value.In this paper, based on the finite element program of ANSYS, on the basis of the stress-strain models of determining the steel and concrete under dynamic actions; In this paper, 4 series 13 specimens of SCFRST columns which around the weak-axis bending and 4specimens of CFDRST columns which around the strong-axis bending are tested under cycle loading, the main parameters are axial compressive force ratio, steel ratio, slenderness ratio and section height to width ratio. The results of the experiment have been analysed and compared, which in cludes the rule of P-â–³behavior, hysteretic behavior, axial shortening, stiffness decay, energy dissipation, skeleton curve, ductility capacity. The test results show that:â‘ the SCFRST columns which around the weak-axis bending has plump hysteretic loops; good ductility and evening deformation ability after the joints reach ultimate load;The energy dissipation coefficient is between 2.64 and 2.94,which shows that the SCFRST columns which around the weak-axis bending has superior seismic behavior and energy dissipation ability;â‘¡Through analyzing the curves we can know that the influence of the axial compressive force ratio, steel ratio, slenderness ratio and section height to width ratio on the hysteretic behavior of the SCFRST columns is concluded, and the axial compressive force ratio, steel ratio, slenderness ratio and section height to width ratio are the main keys influence factor for the hysteretic behavior;â‘¢The CFDRST columns which around the strong-axis bending has plump hysteretic loops; good ductility and evening deformation ability after the joints reach ultimate load; With the hollow section ratio increased, the level of bearing capacity of the manufacturing increases, but the energy dissipation coefficient decreased gradually reduce, and its seismic behavior decreased gradually reduce.The paper analyzes bearing capacity of the SCFRST columns which around the weak-axis bending and the CFDRST columns which around the weak-axis bending under the monotone circle load deeply. It is valuable to modify related codes, and to direct practical engineering design. It is a good foundation for earth-quake resistance of the concrete filled steel-tubular structure.