Strengthening of shear-dominant reinforced concrete beams with ultra-high-performance concrete jacketing

This study investigates the behavior of shear-dominant beams strengthened with 150 MPa ultra-high-performance concrete (UHPC) through the experiments of the thirteen full-scale test specimens. Test variables are the strengthening method (side- and U-shaped strengthening), thickness of the UHPC jackets, and fiber volume fraction of the UHPC. The test results showed that the failure mode, load-resistance capacity, ductility, and stiffness were significantly affected by the thickness of the UHPC jackets and strengthening type. Due to the UHPC jacketing, the shear-dominant beam was converted into a flexural beam. These results greatly contributed to the improvement of the load resistance and ductility of the strengthened beam. The UHPC jacketing technique increased the load resistance of the shear-dominant RC beam by up to 35 % and 88 % for side- and U-shaped strengthening. Furthermore, this technology improved ductility and stiffness of existing RC beams by 21 %∼61 % and 9 %∼77 %, respectively. Finally, based on the experimental results, the flexural and shear strength of the UHPC strengthened beam was proposed.