Performance of circular CFST column to steel beam frames under lateral cyclic loading

This paper presents the study on the behavior of composite frames with circular concrete filled steel tubular (CFST) columns to steel beam. Six composite frames were tested under a constant axial load on the CFST columns and a lateral cyclic load on the frame. Each frame specimen consisted of two CFST columns and a steel beam to represent an interior frame in a building. A finite element analysis (FEA) model was developed to investigate the behavior of the composite frame. The results obtained from the FEA model were verified against those experimental results. Detailed analysis was carried out on longitudinal stress in steel beams, axial stress distribution in concrete, concrete stress along the column height and at the connection panel. Parametric studies were conducted to investigate the influence of axial load level, beam to column linear stiffness ratio on the structural behavior of composite frames. A simplified hysteretic lateral load (P)(P) versus lateral displacement (Δ)(Δ) model was proposed for such composite frames.

Research highlights
► Experiments on frames consisting of CFST columns subjected to cyclic loading.
► Finite element simulation of the nonlinear behavior of the composite frames.
► Simple technique for approximating the hysteresis response of composite frame.