A Unified Nonlinear Fiber-Based Framework for Predicting Axial–Flexural Interaction in Reinforced Concrete Shear Walls
Islam Ibrahim Shoheb1,*, Moustafa Metwally2, Intan Rohani Endut2
1Technical Manager, MAS Engineering and Construction Company Ltd., KSA
2 Graduate School of Management (GSM), Management and Science University, Shah Alam, Malaysia
Emails: Eslamshohip03@gmail.com; 012024021443@gsm.msu.edu.my; Intan_rohani@msu.edu.my
Purpose - Reinforced concrete (RC) shear walls are critical lateral-load resisting elements; however, reliable prediction of their axial–flexural interaction behavior remains difficult, particularly for irregular geometries and nonuniform reinforcement layouts. This study aims to develop an accurate and versatile analytical framework to evaluate the global axial–flexural response of RC shear walls. Design/methodology/approach - A fully nonlinear, code-independent numerical framework is formulated based on strain compatibility, equilibrium enforcement, and curvature-controlled sectional analysis. The model incorporates advanced stress–strain relationships for confined and unconfined concrete, a bilinear steel constitutive law, and a high-resolution fiber discretization scheme capable of representing arbitrary cross-sectional shapes. The framework generates complete moment–curvature responses and axial–moment (P–M) interaction diagrams under uniaxial bending. Findings - The results exhibit strong agreement with established analytical models and reported experimental trends. The framework accurately captures nonlinear degradation, neutral-axis migration, confinement effects, and the influence of reinforcement distribution on axial–flexural capacity. Practical implications - The proposed model provides a reliable tool for performance-based assessment, design, and optimization of RC shear walls beyond simplified code provisions. Originality/value - The study introduces a geometry-independent, fully nonlinear modeling approach that enables detailed evaluation of irregular RC shear walls with enhanced accuracy and practical applicability.
Keywords: Axial-flexural behavior; Confined concrete; Fiber modelling; Interaction diagrams; Nonlinear analysis; Reinforcement optimization; Shear walls