Utilization of hybrid approach towards advanced database of concrete beams strengthened in shear with FRPs

This paper concerns the shear behavior of reinforced concrete beams externally strengthened with composite materials. The study gathers numerous experiments on concrete beams, strengthened in shear with FRPs, from the international literature and develops an experimental database. The database is utilized to assess the predictive accuracy of significant existing design recommendations, with respect to the vertical load capacity of the tested beams. The crucial parameters for predicting the shear capacity of FRP strengthened beams are identified. Some of these parameters are disregarded in the reported results of several experimental programs or are difficult to measure. The research utilizes the available full load-deformation curves for numerous tests as well as the predictive accuracy and easy to apply modified compression field theory (MCFT). Reverse MCFT analysis of beams may provide significant information concerning the angle of main shear crack, the average crack width of concrete and the average effective deformation of the FRP and of internal steel, given the failure load. Thus, a hybrid approach is followed to enrich the experimental database with analytically derived significant parameters towards an advanced database. The hybrid experimental–analytical database is further elaborated and recent studies on shear behavior of concrete members are taken into account. The study explores the influence of different crucial parameters and proposes suitable modifications of existing design equations towards remarkably improved shear force resistance predictions.