International Journal of BIM and Engineering Science IJBES 2571-1075 10.54216/IJBES https://www.americaspg.com/journals/show/4271 2021 2021 Technical Manager, MAS Engineering and Construction Company Ltd., KSA Islam Islam Graduate School of Management (GSM), Management and Science University, Shah Alam, Malaysia Moustafa Metwally Graduate School of Management (GSM), Management and Science University, Shah Alam, Malaysia Intan Rohani Endut Purpose: This study develops a code-agnostic, mechanics-first framework to quantify the parametric sensitivity of axial flexural (N-M) interaction in reinforced concrete (RC) shear walls and to produce transferable rankings of key “design knobs” controlling N–M response metrics. Designmethodologyapproach: A strain-compatibility, fiber-based sectional solver is formulated for rectangular, T, IH, and U-shaped wall sections. The mechanics engine is decoupled from a modular code-profile layer (ACI-EC2-BS-consistent mappings) to enable cross-code comparisons. Interaction curves are normalized to isolate mechanics-driven shape effects, and scalar metrics are extracted at multiple axial levels (e.g., M^* (N^*=0.1,0.3,0.5), Mmax, and balanced-point indicators). Sensitivity is quantified using local elasticities, Morris screening, and Sobol variance-based indices; numerical reproducibility is verified through convergence and mesh-independence controls. Findings: Normalization collapses most cross-code variability in curve shape, while design-level curves retain separable safety-format differences. Sensitivity rankings vary with axial level and section family, revealing nonlinear interactions and regime shifts especially for irregular sections where flange participation can dominate near peak or balanced states.  Practical implications: The framework supports cross-code traceability and efficiency-based design guidance (steel and boundary efficiency) across axial regimes, highlighting diminishing returns and marginal benefits. Originalityvalue: The study delivers a reproducible, code agnostic N–M engine integrated with rigorous global sensitivity analysis to bridge the gap between sectional mechanics and design-oriented decision-making. 2026 2026 75 96 10.54216/IJBES.120105 https://www.americaspg.com/articleinfo/22/show/4271