Assessing the Seismic Performance of Prefabricated Coupling Beams Using Double-Lap Sleeves: An Experimental and Numerical Investigation

To advance the application of prefabricated structures, this study proposes a novel sleeve connection for reinforced concrete coupling beams, aiming to balance the construction efficiency with seismic performance in prefabricated structures. Quasi-static tests and numerical simulations were conducted, investigating the effects of span-to-depth ratio, connection type, and casting method. The experimental results demonstrate that the proposed sleeve-connected beams exhibit seismic performance comparable to, and in some cases superior to, their cast-in-place counterparts. Specifically, the prefabricated specimen with a span-to-depth ratio of 4 achieved approximately 85% of the energy dissipation capacity of its cast-in-place counterpart. However, as the span-to-depth ratio decreased, the energy dissipation capacity of the prefabricated beams increased significantly, reaching up to 2.5 times that of the cast-in-place specimens. Numerical simulations, which showed good agreement with experimental results in terms of failure modes and hysteresis curves, further revealed that concrete compressive strength has a limited influence on seismic behavior. In contrast, increasing the reinforcement ratio effectively improved stiffness and ductility. Notably, increasing the rebar diameter from 18 mm to 22 mm resulted in approximately 25% improvement in energy dissipation capacity. The findings provide novel insights and a scientific basis for the practical application of this innovative prefabricated solution.