Enhancing the shear ductility in RC beams: A novel fiber reinforced polymer-rubber support composite (FRP-RSC) strengthening approach

Abstract

At present, fiber-reinforced polymer (FRP) is extensively utilized to strengthen steel-reinforced concrete (RC) beams, thereby augmenting their structural shear capacity. Nonetheless, the potential for brittle shear failure in FRP-strengthened RC beams remains a challenge, as the sudden rupture of a specific FRP strip may occur without fully exploiting the other strips. To address this issue, this study introduces rubber support composite (RSC) to the bottom of RC beams and, forming a series of plastic hinges. In the event of debonding of a particular FRP strip, the shear load can be transferred to adjacent FRP strips, facilitating a uniform stress/strain redistribution across the RC beam and safeguarding the FRP from abrupt failure. Experimental outcomes reveal that an increase in CFRP layers may result in earlier and larger RSC compressive deformation for bonded FRP-beam cases (1:1.42:2.89 for 1–3 FRP layers) but has no significant effect on unbonded FRP-beam cases (1:1.45:1.32 for 1–3 FRP layers). Compared to the conventional FRP reinforced beam, the proposed FRP-RSC strengthening system effectively enhances the shear performance of RC beams, exhibiting comparable structural shear capacity, 2.1–104.1% higher ductility and 9.3–128.3% advanced energy dissipation than conventional FRP reinforced beam. Moreover, the effectiveness of the FRP-RSC system is demonstrated through comparisons with other conventional reinforcing treatments. Given its cost-effectiveness, ease of implementation, and suitability for practical engineering applications, the FRP-RSC system is anticipated to have promising prospects for future utilization.