Effect of Ring Beam Diameter on Mechanical Properties of CFST Column-RC Beam Joints

As a new type of combined member with high bearing capacity, high stiffness and good ductility, concrete-filled steel tubular(CFST) structure is widely used in super high-rise structures. The connection of CFST columns and reinforced concrete(RC) beams has been a key issue of concern for scholars and engineers at home and abroad. In this paper, the influence of different ring beam diameters on the mechanical properties of the new CFST column-RC beam joint is investigated by using finite element analysis. The results showed that when the diameter of the ring beam was increased from 500 mm to 700 mm, the initial stiffness, peak load, peak displacement and reinforcement stress level of the specimens increased by 4.2%, 11.4%, 7.5% and 4.6%, respectively, which indicated that the increase in the diameter of the ring beam could increase the bearing capacity of the joint with limited effect.