Seismic behaviour of full-scale prefabricated RC beam–CFST column joints connected by reinforcement coupling sleeves

Abstract

This study evaluated a new type of joint for connecting reinforced concrete (RC) beams with a concrete-filled steel tube (CFST) column that consists of U-shaped steel end plates and longitudinal reinforcement coupling sleeves. The proposed joint configuration was designed to fully realise the advantages of prefabricated structures, including a short construction period, easy construction control and low environmental impact. Low-cycle reversed loading tests were conducted to evaluate the seismic behaviour of three full-scale joint specimens, namely a cast-in-place joint and two prefabricated RC beam–CFST column joints connected using reinforcement coupling sleeves. The results indicate that the prefabricated joints exhibited plumper load–displacement curves and a good connection behaviour. The prefabricated joints failed in bending, thereby resembling the failure of the cast-in-place RC beam–CFST column joint. The failure region was concentrated in the area outside of the U-shaped end plate. The coupling sleeve connection was reliable, and the plastic hinge at the beam end moved further outward. Compared to the cast-in-place joint, the prefabricated RC beam–CFST column joints exhibited a similar bending capacity. The ductility coefficients of the prefabricated RC beam–CFST column joints increased about 5.2% and 2.6%, respectively. The average energy dissipation coefficient increased by 0.71% and 1.74%. The cumulative energy consumption and working index showed no significant difference.