Path following strategies for non-linear analysis of steel-concrete composite sections: a bi-axial bending evaluation

Resumo

The present study aims at the non-linear analysis of steel-concrete composite cross-sections. The strain compatibility method (SCM) is used to describe the 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. Concomitantly, the strain-control strategy is implemented as an alternative numerical approach and used for comparison, since the bending moment limit points do not prevent the complete construction of the cross-section equilibrium path. The constitutive relationships are addressed explicitly, as well as the residual stresses present in the steel sections. To validate the proposed numerical formulation, the results obtained are compared with the numerical and experimental data available in the literature. To validate the proposed numerical formulation, the results obtained here are compared with the numerical data available in the literature. Additionally, the softening effect on the concrete was increased to induce descending stretches in the moment-curvature relationship, and this condition was correctly evaluated.