Path-following strategies for nonlinear analysis of steel-concrete composite cross-sections: a bi-axial bending evaluation
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The present study aims at the nonlinear analysis of steel-concrete composite cross-sections. The strain compatibility method (SCM) is used to describe the cross-sections deformed shape in each step of the incremental-iterative solution process. For the full analysis of the moment-curvature relationship, the SCM is coupled to path-following strategies (adapted generalized displacement technique and adapted minimum residual displacement method) to go beyond the critical bending moment points in the construction of the relations that describe the complete cross-section mechanical behavior. The research explicitly addresses the constitutive relationships, as well as the residual stresses present in the steel sections. For each applied normal force, evaluations of oblique composite bending are conducted, considering combinations of bending moments around the major and minor axes, and considering different inclinations of the cross-section neutral axis. To validate the proposed numerical formulation, the numerical results obtained here are compared with the numerical and experimental data available in the literature. The successful computational implementations mirrored the expected results found in the literature. By increasing the softening effect on the concrete, descending branches in the moment-curvature relationship are calculated and correctly evaluated this condition.