Numerical and Experimental Study of Coupling Beams in Reinforced Concrete Shear Walls with Diagonal Steel Members

The seismic performance of coupling beams in reinforced concrete shear walls is a critical factor in ensuring the safety and resilience of high-rise buildings, particularly in earthquake-prone regions.According to ACI 318, diagonally reinforced coupling beams are designed to deliver superior seismic performance, including ductility and energy dissipation.However, the intricate layout and congestion of diagonal reinforcement pose significant challenges during construction.To address these issues, this study proposes a new type of reinforcement approach-Equivalent Diagonal Reinforcement (EDR)utilizing diagonal steel elements (DSE) in the form of L-and box-shaped profiles.This study involves both analytical and experimental investigations on three coupling models: one with conventional diagonal reinforcement in accordance with ACI 318 (DRAC) and two, incorporating the proposed EDR system.The EDR-based models use diagonal steel elements in either box-shaped or L-shaped profiles.Experimental and numerical approaches were utilized to assess the seismic behavior of the coupling beams.Cyclic loading tests were conducted to analyze crack propagation, failure modes, and energy absorption, while finite element simulations using ABAQUS/CAE 2022 were employed to validate the experimental findings and provide further insights into stress distribution and post-peak behavior.The findings demonstrate that the proposed EDR system with diagonal steel elements effectively addresses reinforcement congestion issues while achieving desirable performance in terms of stiffness degradation, energy dissipation, and ductility improvement.This study suggests that EDR can serve as a viable alternative to conventional diagonal reinforcement, enhancing both constructability and structural performance.