Elasto plastic behavior of steel beam to square concrete filled steel tube (CFT) column connections

This paper proposes a non-linear load deformation relation model for the panel zone of steel beam to square CFT column connections for predicting an elasto plastic behavior of the panel zone. The model is based on superimposition of the tri-linear relation for the steel tube and the infill concrete. For the ultimate strength of the infill concrete, an evaluation method for load resistance is proposed, assuming a new theoretical arch mechanism. The analytical results agree approximately with the experimental results up to a large shear deformation of 0.04 radians, of which strength of the steel tube and the infill concrete is ranged from ordinary to high, with internal diaphragm, external diaphragm and other stiffening parts.