Seismic behavior and shear capacity calculation of a new type of self-centering steel-concrete composite joint

Abstract Based on post-earthquake resilience principles, this study proposes a novel self-centering steel-concrete composite joint. The joint employs prestressed connections, where an assembled column with an embedded steel sleeve in the core region is connected to a steel-concrete composite beam via high-strength bolts. Energy dissipation is achieved through dedicated energy-dissipating plates. Three interior joint specimens were designed and modeled using ABAQUS finite element software to investigate their seismic performance under low reversed cyclic loading. The effects of energy-dissipating plates and prestressed steel strands on joint behavior, including bearing capacity, failure mode, self-centering capability, and energy dissipation, were systematically analyzed. Furthermore, the formula for calculating the joint’s shear capacity was derived using the superposition method. Two joint specimens derived from the prestressed self-centering (PSC) prototype were designed to benchmark the proposed formula’s computational results against finite element analysis outcomes, thereby validating the formula’s accuracy in assessing the actual shear capacity of joint core regions. Results demonstrate that the proposed joint exhibits high bearing capacity, excellent energy dissipation, and effective self-centering. Prestressed steel strands significantly reduce residual drift and provide self-centering capability, while energy-dissipating plates mitigate stress fluctuations in the strands, preventing premature yielding. Crucially, damage localizes primarily within the replaceable energy-dissipating plates, enabling post-earthquake functional recovery through plate replacement. The load-bearing mechanism of the novel self-centering steel-concrete composite joint conforms to the strut-and-tie mechanism. The calculated values from the formula show good agreement with the results obtained from finite element simulations.