In this paper, the implementation of an elastoplastic constitutive model with cracking is presented for analyzing reinforced concrete structures using The Finite Element Method (FEM). This implementation was made through the UPF (User Programmable Features), a customization tool available in ANSYS (version 14.5). By using the UPF features, a new constitutive model for concrete was created (in USERMAT3D), adding new subroutines in FORTRAN language to the main program. The main advantage of the implementation of this model is the possibility of using quadratic twenty-node three-dimensional elements (SOLID186) with the element-embedded rebar model (REINF264), making the solution considerably faster and more effective, when compared to typically available options. In order to validate the subroutines added to the system, the beams tested by Leonhardt and Walther (1962) were simulated, covering a wide variety of behaviors, including bending and shear failures. Analyses of the stresses in the concrete and in the reinforcement are made and load-displacement diagrams are presented. The comparisons that are done between numerical and experimental results demonstrate the validity of the results found.
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