Parametric Study on the Behavior of Coupled Shear Walls with High-Performance Fiber-Reinforced Concrete Coupling Beams: Influence of Key Design Parameters

Coupling beams significantly influence the performance of coupled shear wall systems under lateral forces. To ensure adequate behavior under lateral load-induced deformations and stresses, coupling beams are typically reinforced with complex reinforcement configurations, such as diagonal bars and confinement reinforcement. However, these reinforcement schemes can complicate construction. In slender coupling beams with an aspect ratio of approximately 3.0, the shallow angle of the diagonal reinforcement (less than 20 degrees) relative to the beam's longitudinal axis raises questions about the effectiveness of this reinforcement. This study investigates the impact of utilizing tensile strain-hardening high-performance fiber-reinforced concrete (HPFRC) in coupling beams. A nonlinear static analysis using the Applied Element Method was conducted to assess the behavior of coupling beams with HPFRC. The analysis was validated using previously tested specimens. A parametric study was performed, considering factors such as the material type (HPFRC vs. regular concrete), the longitudinal reinforcement ratio in coupling beams, the incorporation of HPFRC within the coupled walls, the presence of diagonal reinforcement with or without confining stirrups, the coupling beam's aspect ratio, and the fiber ratio. The results indicated that the use of HPFRC enhances the beam's capacity and provides superior energy dissipation compared to traditional reinforced concrete.