Failure of beams made of Steel Fiber Reinforced Concrete (SFRC) and strengthened with plates of Fiber Reinforced Polymer (FRP) typically occurs after the detachment of the FRP plate, and depends on the content of steel fibers. Relevant finite element simulations are few, and, usually, neglect the modeling of the detachment process. On the contrary, the proposed regularized eXtended Finite Element Model (XFEM) focuses on the detachment process. In particular, the present approach takes into account the fiber-bridging effect exerted by the steel fibers at the detachment zone, while modeling the detachment through a mechanism-based procedure. The obtained results are fully consistent with the experimental data.