Seismic performance of T-shaped CFST column to U-shaped steel composite beam joints

U-shaped steel-concrete composite beams have the advantages of high bearing capacity, excellent fire resistance and quick construction, when it is used with special-shaped concrete-filled steel tube columns could achieve the architectural effect of no exposed beams and columns in the interior, showing great application potential in residential buildings. In this study, three full-scale T-shaped CFST column to U-shaped steel composite beam joints with different configurations were tested under cyclic loads. The damage modes, and hysteresis performance of the joint were discussed in detail. The test results indicated that the three joints with side plate connection all showed plastic hinge damage at the beam ends of which hysteresis curves show bowed shape, with excellent energy dissipation. The setting of truss reinforcement within the U-shaped steel beam could effectively improve the ductility of the member. Based on the validated finite element model, the effects of side plate configuration, the side plate position, and tube wall thickness on the seismic performance of the joints are investigated. The design methods for the bending capacity of the joints have also been proposed.