Cyclic behaviour and design of cold-formed round-ended concrete-filled steel tube columns

This paper presents a detailed investigation of the performance cold-formed round-ended concrete-filled steel tubular (RECFT) columns under cyclic loading via experimental and numerical approaches. Experimental tests observations this type novel composite column are presented, its failure modes, hysteretic curves, ductility ratio, energy dissipation, stiffness, strength degradation revealed. A nonlinear finite element (FE) model RECFT is established verified by test results. Additional parametric analyses on effect material strength, axial compression diameter/thickness aspect direction subsequently performed using validated FE methodology. Simplified prediction methods proposed to assess initial flexural ultimate displacement, descending stiffness lateral force. The results indicate that modes mainly include concrete crushing, local buckling, fracture tube. with section exhibits good behaviour, high ductility, sufficient energy-dissipation capacity.