Experimental study on interior precast concrete beam-column connections with UHPC core shells

Abstract High-performance materials are increasingly being used in precast connections to improve their mechanical performance and simplify the construction process. In this study, a novel precast beam-column connection with an ultrahigh-performance concrete (UHPC) core shell is proposed, which works as the permanent joint formwork in the precast stage and the strengthening overlay during normal service. To investigate the seismic performance of the proposed connection, a total of three precast specimens and one reference monolithic specimen were tested through the quasi-static method. The main variables in this study were the thickness of the UHPC shell and the layout and ratio of stirrups in the joint zone. The test results indicated that the UHPC core shells effectively limited the shear behavior, delayed cracking in the joint zone, and provided plump hysteretic performance. With the assembly configuration, the proposed connection had good ductility and an efficient energy dissipation capacity. The UHPC shell configurations with variable stirrup layouts and ratios led to different crack patterns in the joint core zone. In addition, strengthened by the UHPC shells, the joint cores could be reinforced with fewer stirrups than demanded by code.