Fully nonlinear analysis of steel-concrete composite girder with web local buckling effects

A reliable and advanced program for nonlinear inelastic analyses of steel girders and steel-concrete composite girders subjected to flexural loadings has been developed in the current article. Effects of geometric nonlinearities, material nonlinearities, and residual stresses on flexural behaviors of different steel girders and steel-concrete composite girders have been thoroughly investigated. The concrete slab and steel I-beam cross-sections are discretized into fiber elements to formulate an equivalent effective cross-section. The P - delta effect of beam-column elements is investigated by using stability functions, wherein the plasticity spreading phenomena in the element cross-section are captured at different integration points along the longitudinal direction of the element based on constitutive relations in each fiber. The local buckling phenomenon that possibly occurs in web plates of non-compact composite sections has been considered by considering its effective width formulas for the first time. The generalized displacement control method is applied to solve nonlinear equilibrium equations. The proposed program validated by experimental results shows its accuracies in capturing the structure behaviors and its efficiencies in computing time compared with finite element analyses performed in ABAQUS. Different parametric studies are conducted yielding notable observations. The proposed program might be used as an efficient tool in practical advanced analyses and designs of steel girders and steel-concrete composite girders with high nonlinearities and complexity.