Experimental study on seismic performance of novel fabricated T-joint with replaceable steel hinges

Beam-column joint plays an important role in structural integrity as well as the mechanical behaviour of precast concrete structure, which has been widely applied in civil infrastructures. To improve the seismic performance and the earthquake resilience of precast concrete structure, a novel replaceable steel hinges was applied in the fabricated T-joint in this paper. The T-joint is composed of prefabricated column, prefabricated beam, a replaceable steel hinge with a steel damper, and the core area of the steel damper is constrained by steel sleeves. Pseudo-static tests on the seismic performance of the fabricated T-joint with replaceable steel hinges and the monolithic reinforced concrete joint were first carried out, and then the repaired fabricated T-joint after replacing the damaged steel damper in steel hinge was tested again under cyclic loading. The failure mode, hysteretic behaviour, degradation in strength and stiffness were discussed, and earthquake resilience of the proposed joint was evaluated. The results demonstrated that the bearing capacity, energy dissipation capacity, and ductility of the novel fabricated T-joint with replaceable steel hinges were better than that of the monolithic reinforced concrete joint. It was observed that the damage region of the novel fabricated T-joint was concentrated in the steel dampers of the replaceable steel hinge, while the prefabricated column remained in elastic state without visible cracks. Moreover, the repaired fabricated T-joint could develop desired bearing capacity, ductility, energy dissipation compared with the original specimen, though the stiffness of the repaired fabricated T-joint decreased a bit in the early stage. It was validated that the function of the damaged fabricated joint could be well restored after replacing the damage elements, therefore, the novel fabricated T-joint with replaceable steel hinges could develop favourable earthquake resilience.