Seismic actions may cause the breakdown of the dowel and aggregate interlocks mechanisms of RC beams, after which the stirrups are the only viable mean of shear resistance. In the zone of the RC beam with vertical cracks, however, also the stirrups do not provide any contribution to the shear capacity. FRP reinforcement epoxy-bonded onto the web is the only viable mean of retrofitting such RC beams, provided that side bonded sheets with diagonal fibers are used. This paper presents an analytical model devoted to this special shear state, together with a test and two applications.