BEHAVIOR OF CFST-COLUMN TO STEEL-BEAM JOINTS IN THE SCENARIO OF COLUMN LOSS

As a connecting component in structures, the mechanical property of joint is one of the critical factors, especially to prevent progressive collapse.In the scenario of column loss, the joints are subjected to bending moment combined with tension to redistribute loads, which is different from the behavior of joint in an undamaged structure.According to this specific loading condition, two concrete-filled steel tubular column-steel beam joints under bending moment combined with tensile force were tested.In the test, a new kind of semi-rigid joint was proposed, whilst an outer-ring configuration was adopted in a rigid joint for comparison.Meanwhile a finite element model of the new joint was developed by using ABAQUS.The results show that new semi-rigid joint possesses good rotation capacity under pure bending moment.The initial stiffness and moment resistance of the new joint are both smaller than those of the outer-ring joint.The moment-tension relationship of new joint keeps linear.The behavior of joint under moment combined with tensile force may be uniformly described by a power function correlation expression.The influence of width of short-limb connected to tube wall and the limb thickness on the initial stiffness and strength of new joint is obvious whilst the influence of width of long-limb connected to beam flange is not evident.