Component-wise approach to reinforced concrete structures

With the rapid development of engineering constructions, especially transportation facilities, the structural models for the simulation of large-scale structures shall be eventually enhanced for predicting the complete three-dimensional stress and strain fields in reinforced concrete-made components. This paper proposes a component-wise approach for the modeling of reinforced concrete structures in which steel rebars and the concrete part are considered as two independent one-dimensional entities. Lagrange polynomials are used to express the cross-section deformations and different component-wise subdomains are joined by simply imposing displacement continuity at the chosen Lagrange points along the component boundary. The Finite Element (FE) method is applied to provide numerical solutions whereas Carrera Unified Formulation (CUF) is used to generate the related stiffness matrices in a compact and straightforward way. The classical case of homogenized beam solutions, as well as the one in which a virtual layer is associated with the steel zones, are implemented too. The three solutions are compared for a number of reinforced concrete beam problems, from single to double reinforced beam, including a T-shape cross-section. A final study considering transverse stiffeners (steel stirrups) is investigated. These stiffeners are modeled component-wise as well. Results clearly show the advantages and superiority of the component-wise FE-CUF based model to completely capture the three-dimensional strain and stress states, including shear ones, of reinforced concrete structures.