In this paper, a hidden ring beam (HRB) joint suitable for steel-tube-reinforced concrete (ST-RC) composite columns is proposed. The seismic performance was evaluated experimentally by hysteresis loading tests on reinforcement anchorage construction and reinforced concrete (RC) slabs, which was evaluated by several indices to assess the strength, ductility, stiffness degradation and energy dissipation capacity. The results showed that the HRB joints have reliable seismic safety performance. The ultimate failure of all the specimens occurred in the plastic hinge regions of the RC beams. The specimens with different reinforcement anchorage construction methods exhibited excellent anchorage performance, maintaining effective anchorage between beam longitudinal bars and ring bars under cyclic loading. The RC slab increased the joint strength and the initial stiffness, with only a reduction in the ductility coefficient, and the average equivalent viscous damping coefficient reached 0.155. In addition, a joint numerical model was established, and the accuracy was validated against the test results, with the predicted strength differing from the test results by no more than 6%. A parametric analysis using numerical simulations revealed that the ring–longitudinal ratio, bearing stirrup diameter, RC slab constraints and axial load ratio were critical factors influencing the seismic performance of the joints. On the basis of the results of the parametric analysis, a moment capacity calculation method is proposed for HRB joints, providing a practical reference for seismic design in engineering applications.
Ling et al. (Thu,) studied this question.