Experimental study of earthquake-resilient prefabricated composite joint with T-shape connector

Abstract

Based on the idea of damage control, a new type of earthquake-resilient prefabricated composite joint (ERPCJ) with the T-shape connector has been proposed. On the premise of considering the composite action of concrete slab and beam-column joint, the seismic behavior, post-earthquake recoverability and failure mode of concrete slab under different loading protocols are studied. By changing the connection mode between flange cover plate (FCP) and beam, the influence of the relative slip between FCP and beam on the bearing capacity and energy dissipation capacity of the specimen are also studied. The low frequency cyclic loading tests and low cyclic fatigue tests of six specimens show that the basic and repaired specimens of the prefabricated composite joints with recoverable functions show good seismic behavior. The plastic damage of steel joint is concentrated on FCP, while the main structural members such as beam and column still maintain elasticity. The collaborative work of T-shape connector with foams, concrete slab and the gaps between concrete slab and column can reduce the plastic damage of concrete slab. The main reason of concrete slab damage is the strong squeezing effect between concrete slab and T-shape connector in negative moment zone. Whether FCP can slip or not can make a great difference in the bearing capacity and energy dissipation capacity of the joint. The damage and deformation of FCP are small when FCP and beam can slide relatively, but the bearing capacity and energy dissipation capacity of the joint are low. The bearing capacity and energy dissipation capacity of the joint are high when FCP and the beam cannot slip relatively, but FCP will cause serious plastic damage and even fracture.