A Class of Finite Elements for Nonlinear Analysis of Composite Beams

In this paper, we investigate the performance of three finite element formulations for continuous composite beam analysis. These formulations include displacement-based, force-based and mixed models. Specific attention is devoted on how to take into account discrete connection which seems, in some cases, to be more representative of the actual behavior. The nonlinear behavior of concrete is modeled using a softening plasticity model. The parameters of the models are obtained by matching the uniaxial stress-strain relationship provided by the CEB-FIP 90 model. Tension-stiffening is taken into account as well. A consistent time-integration is performed using the Euler backward scheme. The predictions of the FE models are compared and the study shows good performance of the mixed formulation.