Retrofitting of Shear-Deficient RC Beams Using UHP-FRC

Abstract

The shear-deficient structural elements affect the designed serviceability of structures. The early decay in serviceability reduces the functionality of the structures and leads to global failure of the structure. The retrofitting offers a greater flexibility to restore the serviceability by restrengthening the distressed structural elements. The concrete, ferrocement and fiber-reinforced polymers (FRPs) jacketing are some of the retrofitting techniques tried in the past. But all these techniques have their associated advantages and disadvantages; for example, one of the disadvantages of FRP jacketing is a brittle failure due to debonding of FRP. These failures restrained the serviceability of retrofitted structure elements. In the current study, the newly developed material, i.e., ultra-high-performance fiber-reinforced concrete (UHP-FRC), is being used to retrofit the shear-deficient reinforced concrete beam. The high compressive strength (above 110 MPa), high tensile strength due to the addition of fibers, high flexural strength, very low permeability and high workability of UHP-FRC are expected to improve the performance of retrofitted RC members. Hence, the performance of UHP-FRC as a retrofit material for beams deficient in shear is explored in the present experimental study. The beams designed deficient in shear are initially stressed to 60% of the ultimate failure load and then retrofitted by UHP-FRC. The U-type retrofitting and external side face jacketing are used to retrofit the initially stressed beams. The results show that the behavior of retrofitted RC beams improved in terms of ultimate load carrying capacity, ductility and energy absorption. Further, it is observed that the U-type retrofitting is better than side face jacketing retrofitting.