Assessments of current models for FRP shear strengthened reinforced concrete beams

The problem of the evaluation of the shear strength in RC beams reinforced by fibre reinforced polymers (FRP), is a very complex subject. The actual most important codes/recommendations quantify the nominal shear strength by means of a simple sum of the contributions of concrete (Vc), steel (Vs), and FRP (Vf). This kind of approach has been discussed by various authors [1-6], which observed that the presence of the FRP could influence the effective stress in the internal steel. Furthermore, the problem of estimating the angle of the concrete compressed strut in the strengthened beam is actually an issue under discussion. This paper presents a broad comparison between the experimental results sourced from a number of experimental investigations and the analytical formulation of the most important codes/recommendations available in literature. The database is made by the results of 166 RC beams strengthened with different configurations and subdivided according to the presence or not of internal stirrups. Comparisons between these experimental results and the corresponding analytical formulations are presented and discussed.