Shear strengthening performance of post-tensioned UFC panel on reinforced concrete beams

Abstract

The ultra high strength fiber reinforced concrete (UFC) is an advanced cementitious material which grants the high performances in strength, durability, and ductility. Because of these high performances, in this study, it was applied into the new idea for shear strengthening to RC beams, namely the post-tensioned UFC panel. It is the prefabricated UFC panel prestressed by some prestressing force. Three parameters (i.e., the number of post-tensioned UFC panel, the amount of prestressing rods, and the prestressing level in the UFC panels) were studied from eight strengthened beams for investigating the shear strengthening performance. All specimens were subjected to four-point bending. The results of the strengthened beams and the non-strengthened beam revealed that the strengthening by post-tensioned UFC panel increases the shear capacity, stiffness, and ductility of the beams. Moreover, the prestressing level also influenced the delay of the initial cracking load and the yielding of stirrups. Finally, the shear capacity carried by the post-tensioned UFC panel was proposed by using the force equilibrium along the assumption of imaginary diagonal crack.