In this study, a repairing of preloaded RC beams with openings strengthened with steel plate was studied by using finite element package ANSYS14.5. To ensure that the elements, convergence criteria, and material properties are adequate to model the behavior of the RC beam and to ensure that the simulation process is correct, the FE ANSYS was calibrated with published experimental data. The effect of pre-damage level and loading mechanism were considered as main parameters. Furthermore, birth and death technique was used to model the cracks before strengthening stage. In this technique, loading was first applied till the objective cracking, followed by steel plate application, and then the load was continued to failure. The result showed that pre- damage levels and the steel plate strengthening have a great effect on the failure mode and ultimate load of RC beam. In addition, the results showed good agreement with those obtained from published experimental tests. Based on FE using ANSYS an ACI guidelines, an analytical equation for predicting the shear capacity of RC beams with openings strengthened by steel plate under sustained load was then proposed. A comparison of these results yielded valuable conclusions.