Path‐following strategies for nonlinear analysis of steel‐concrete composite cross‐sections: a bi‐axial bending evaluation

Abstract The present study focuses on nonlinear cross‐sectional analysis utilizing the Strain Compatibility Method (SCM) to accurately capture the deformation profile of cross‐sections throughout an incremental‐iterative numerical process. To comprehensively analyze moment‐curvature relationships, the SCM is integrated with path‐following techniques, enabling the numerical solution to extend beyond critical bending moment points and fully describe the mechanical behavior of cross‐sections. This research explicitly considers both the constitutive relationships and residual stresses inherent in steel sections. Evaluations are conducted for oblique composite bending scenarios, involving combinations of bending moments around the principal major and minor axes, while systematically varying the inclination of the neutral axis under different normal force conditions. Validation of the numerical formulation is accomplished by comparing the results obtained from this study with existing numerical and experimental data from the literature, demonstrating excellent agreement. Computational implementations successfully reproduced expected behaviors documented in prior research. Additionally, by incorporating increased concrete softening effects, the descending branches in the moment‐curvature relationships were effectively computed and accurately assessed.