SHEAR CAPACITY OF CONCRETE BEAMS STRENGTHENED WITH CEMENT BASED COMPOSITE MATERIALS

In the paper, the shear capacity of reinforced concrete beams strengthened with externally bonded PBO (short of Polypara-phenylene-benzo-bisthiazole) fibre reinforced cementitious mortar (FRCM) is investigated from both an experimental and a theoretical point of view. The main items being related to the influence of the PBO reinforcement ratio and the configuration of the PBO-FRCM shear strengthening system. At this aim tests on seven PBO-FRCM strengthened reinforced concrete beams has been performed and obtained results discussed. By tests results the effectiveness of the PBO-FRCM as shear strengthening system, the failure modes of strengthened beams, and, the influence of mechanical and geometrical parameters involved in the shear resistance of strengthened beams have been evaluated. In addition, predictions of theoretical models commonly used for the evaluation of the shear capacity of fiber reinforced composite materials (FRP) strengthened reinforced concrete beams have been adopted for a comparison with experimental results.