The contribution at hand focuses on the introduction of a new constitutive approach at finite deformations to represent an initially anisotropic material behavior accounting for fibers within a microplane model. To capture
the specific behavior of concrete structures, a formulation is chosen, which is characterized by damage and plasticity phenomena. To achieve a consistent formulation for finite strain plasticity, a description relative to the plastic intermediate configuration is adopted. Therefore, a simulation of fiber reinforced concrete is enabled at large strains, which overcomes downsides of previous formulations. To overcome numerical instabilities, which can occur in softening phenomena, an implicit gradient enhancement is utilized. The novel formulations, within the microplane framework, enable a sufficiently close approximation of fiber reinforced concrete structures. In the numerical examples, it is demonstrated, that the newly introduced fiber formulation leads to physically meaningful results. Furthermore, a validation of the proposed model is carried out for concrete undergoing more than 30 % strain. Additionally, the fiber formulation is compared to tension tests carried out on textile reinforced concrete. It can be demonstrated, that the proposed formulations can be applied for different volume percentages of fiber reinforcement in concrete structures. As a consequence, it is now possible to simulate fiber reinforced concrete structures consistently for arbitrarily large strains.