FE model for nonlinear analysis of reinforced concrete beams considering shear deformation

In this paper, a finite element (FE) model for nonlinear analysis of reinforced concrete (RC) beams, considering shear deformation, is developed. The model is based on the Timoshenko Beam Theory and utilizes 3-noded bar elements with a total of 7 degrees of freedom. The Fiber Model is adopted, with the element section discretized into overlaid concrete and longitudinal reinforcement layers. Transverse reinforcement, when present, is considered to be smeared and embedded in the concrete layers. The Modified Compression Field Theory with some modifications is utilized for the material constitutive models, and a tension-stiffening model developed by the authors is included. The FE model was implemented into a computer program named ANALEST, developed by the authors, which allows for material and geometrical nonlinear analysis of RC beams and frames. The proposed model is validated via comparison with experimental results from tests on simply supported and continuous RC beams. Comparisons with numerical results from a Bernoulli-beam model are also included, and a few recommendations regarding the use of different FE models are given at the end.