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.