Experimental study on a single-sided resilient composite beam–column joint

This paper presents an experimental study on a single-sided resilient composite beam–column joint, in which a nonreplaceable concrete slab and connection plate and a replaceable buckling-restrained cover plate (BRCP) are installed at the top and bottom flanges, respectively. The seismic performance and replaceability of the proposed joint were investigated considering the influence of the concrete slab. One specimen was cyclically loaded under 2 % rotation, and then the damaged core plate of the BRCP was replaced to form a new specimen that was cyclically loaded under 4 % rotation. The results showed that the neutral axis was shifted upward to the top flange, which made the damage concentrate in the core plate, and only minor damage occurred to the connection plate and concrete slab under 2 % rotation. The hysteresis curve after replacement was almost the same as that before replacement under 2 % rotation and showed full and stable loops without decrease in load capacity under 4 % rotation, implying good seismic performance and replaceability. In addition, the proposed joint was compared with a bare steel joint to examine the effects of concrete slabs. Further, a numerical model of the specimen was developed and verified by comparison with the test results to better understand the test and study the influence of connection plates. Finally, the formulas for the yield moment and initial stiffness of the joint were derived and compared with test results to verify the accuracy of the formulas. The influence of the reduction in core plate area on the joint stiffness and neutral axis position was discussed using the formulas.