Experimental study on seismic behavior of concrete-filled double skin steel tubular column and steel-concrete beam composite joints.

The results of an experimental research involving the testing of six bolted moment-resisting connections under simulated seismic loading conditions were presented. The test specimens modeled the interior joint of a moment-resisting frame consisting of concrete-filled double skin tubular column and H-shape steel beams with reinforced concrete slab using high-strength bolts and T-stub connectors. To investigate the seismic behavior of the composite joints, the failure modes, hysteretic performance, shear strength, bearing capacity degradation, rigidity degradation, energy dissipation and strain were evaluated in detail. The test parameters varied including the axial load level on the column, the stiffener, the size of T-stub, the thickness of slab and the reinforcement ratio in slab. The experimental results indicate that the compressive capacity in column and the shearing capacity in joint are improved by the inserted tube. In some extent, the increase of reinforcement ratio in slab (1% ≤ ρ ≤ ρmax) and the decrease of the loading level on the column (n ≤ 0.3) will improve the total energy dissipation and reduce the ductility of joint, without obvious influence on the joint the bearing capacity. The seismic behavior of joint will be affected by the thickness of T-stub flange and the stiffener. [ABSTRACT FROM AUTHOR]