An efficient elastoplastic model for the analysis of reinforced concrete shells

Shell structures made of Reinforced Concrete (RC) are used in many civil engineering applications. However, their analysis can frequently require a high computational cost, since fine mesh discretisations are needed for accurate solutions. In this work, a Finite Element (FE) for the analysis of RC shells is presented. It has four nodes and 24 degrees of freedom and both generalised stresses and displacements are interpolated. In particular, the assumed stress field a-priori satisfies equilibrium equations, thereby ensuring good accuracy and convergence properties. The heterogeneous material is described through a layer-wise approach in which a 3D stress yield function is used for concrete. Results confirm that the proposed FE is accurate on coarse meshes and shows good convergence properties if compared with state-of-art alternatives. The approach can be readily extended to model additional material layers, for example reinforcements applied for retrofitting purposes.