Design of concrete-filled steel tubular CHS connections in tension

Based on the experimental investigation of concrete-filled steel tubular CHS (circular hollow section) connections, a finite element model was established using ABAQUS and verified against test results. It is shown that the developed model predict the ultimate strength and failure mode of test specimens well. Material properties, sizes of weld and contact interaction between concrete and steel were considered in the developed finite element model. Modified Mohr-Coulomb criterion for ductile fracture was used to define fracture criterion of the steel tube. Distribution of shear stress at the punching shear face was examined and a general equation describing stress distribution was proposed. Parametric study was performed to determine the parameters in the proposed equations. Finally, design equations for ultimate strengths of concrete-filled steel tubular CHS connections failed in chord punching shear failure were proposed.