The shear crack angle is a key parameter in the calculation of the FRP contribution to the shear capacity of a strengthened concrete beam. A non-linear finite element model has been developed to simulate the behavior of six beams grouped in three series according to their dimensions. One un-strengthened beam of each series was used as a benchmark and its behavior was compared to that for a beam strengthened with U-wrap jackets. It was found that the numerical model is able to successfully simulate the characteristics of the shear-strengthened beams. The numerical predictions compare very well with the experimental data in terms of load−deflection relationships. The analysis of the slip profiles along the FRP strip is helpful for understanding the bond behavior between the concrete and FRP strips. The interfacial slip profiles are used to predict the crack formation angle along the shear span, and these predictions agree very well with the experimental measurements. The numerical results give failure modes that are identical to those obtained experimentally.