Experimental Investigation on New Ring-Beam Connections for a Concrete-Filled Tubular Column and RC Beam

This paper introduces a new type of connections—reinforced concrete (RC) ring beam joints between concrete-filled steel tubes (CFSTs) column and RC beam. In this connection, the continuous load transferring in the frame beams are achieved by the transitional ring beam encircling the CFST column. Bidirectional cyclic loading tests on four interior column joint specimens were conducted to evaluate the seismic performance of this new connection system and the influence of the reinforcement on the joint behavior. Test results indicated the multi-directional nature of the force system in the ring beam. RC ring beam should be designed against the combination of multi-directional forces including axial load, bending, torsion, and shear due to the interaction of ring beam and CFST column under external load. The connections with reasonable design were observed to have good ductility and suitable for seismic resistant application.