Experimental seismic study of an innovative precast steel-concrete composite beam-column joint

In this study, three innovative precast composite interior beam-column joints (BCJs) were proposed for convenient construction, high efficiency, and higher seismic performance of precast moment-resisting frames. These composite joints do not have concrete cast-in-place in their core areas. Each specimen of these BCJs consisted of a precast column with a built-in steel skeleton having two end-plates, a precast beam with a built-in H-steel beam, and connecting parts. Three precast specimens and a monolithic reinforcement concrete (RC) reference specimen were tested under reversed cyclic loading to investigate their seismic performance. The test variables were the type of steel skeleton and the beam-column connecting method. The seismic performance of the specimens was evaluated based on the cracking patterns, hysteretic behaviour, stiffness, and energy dissi-pation. The results showed that the proposed composite BCJs exhibited improved bearing capacity and energy dissipation. In addition, the joint cores of the composite specimens maintained their integrity owing to the re-straint imparted to the concrete by the steel skeleton. Furthermore, the shear strength was enhanced signifi-cantly. The beam-column connecting part and precast beam of each precast specimen exhibited flexural failure. This conformed to the standard specification of strong column-weak beam. The steel skeleton and beam-column connecting part functioned reasonably as the force transmission components between beams and column. Thereby, the steel skeleton and beam-column connecting part could effectively aid the construction and improve the seismic performance of the BCJs of the precast moment-resisting frame. Finite element analysis was con-ducted on two recommended precast composite joints, and the simulation results agreed with the test results.