A new higher-order elastoplastic beam model for reinforced concrete

The present paper introduces a new elastoplastic beam model for reinforced concrete based on a higher-order beam model previously developed (Int J Numer Methods Eng. https://doi.org/10.1002/nme.5926 , 2018 ). Steel and concrete are both defined as elastoplastic materials. The beam model represents the concrete body whereas rebars are given a specific discretization. A Rankine criterion is used for concrete in both tension and compression, and a closed-form solution for the local projection of the trial stress on the yield surface is formulated. Steel rebars are modelled with 1D bar elements and added to the global stiffness of the concrete beam model. The kinematics of the higher-order beam model is enriched by a systematic method with displacement modes. This extension of the kinematics leads to local accuracy and yields results comparable to 3D computations. The present reinforced concrete model is validated through a set of case studies. Implemented within the software programs of the company Strains Engineering, the objective is to develop a fast computing and efficient model that can be directly used by engineers.