Design models for shear strengthening of reinforced concrete beams with externally bonded FRP composites: a statistical vs reliability approach

Abstract

[Excerpt] Introduction: Experimental studies conducted worldwide on reinforced concrete (RC) beams strengthened in shear with externally bonded (EBR) fiber-reinforced polymers (FRP) over the last years evince the reliability and efficacy of such technique for structural retrofitting. For elements with shear resistance deficiencies, an higher load carrying capacity may be achieved by bonding FRP reinforcement systems with the fibers as orthogonal as practically possible to the critical shear crack plane for an optimal configuration, or with the fibers normal to the beam axis for a more practical setting. Common configurations of strengthening (Fig.1) include the full wrapping of the cross section (O), U jacketing along 3 sides (U) and side bonding in the beam web (S). Additional mechanical anchorage systems can be provided to enhance the behavior of U or S configurations where the available bond length is short (U+ and S+). [...]