Shear strengthening of RC shear-deficient beams with highly ductile fiber-reinforced concrete

Abstract

This study presents an experimental investigation of reinforced concrete (RC) beams strengthened in shear with highly ductile fiber-reinforced concrete (HDC) jacket. Two batches of beam specimens were loaded under the three-point bending test to determine their ultimate shear capacities. The test variables in this experiment included the presence or absence of original stirrups, thickness of the U–shaped jacket (15 and 25 mm), and the presence or absence of strengthening stirrups in jackets. The failure modes, load–deflection curves, and load–strain curves were described and analyzed. The test results reveal that the HDC strengthened RC beams have improved failure modes and cracking patterns than the unstrengthened beams. The maximum gain in the shear capacity of the strengthened beams ranged from 8.4 to 80.67 % with respect to the reference beam. Moreover, peak deflection can be increased by up to 160.6 %. The strengthening stirrups and original stirrups exhibit a similar strain growth trend, which indicates that the HDC jacket and RC beam work well together, enabling the strengthening stirrups to be effectively utilized. Furthermore, in order to calculate the shear capacity of the HDC strengthened beams, three methods were employed and evaluated.