Effect of FRP Anchor Inclination Angle on Shear Strengthening of Reinforced Concrete T-beams

Abstract

The purpose of this paper is to study the effect of anchoring carbon fiber-reinforced polymer (CFRP) U-Wrapped laminates by CFRP splay anchors to strengthen shear deficient reinforced concrete (RC) T-beams. Recent investigations in this field has proved that CFRP anchors could delay or prevent debonding of CFRP laminates. However, few tests were conducted to study the effect of the FRP anchors on the strength and ductility of RC beams externally strengthened in shear with CFRP sheets. In addition, there are no design guidelines for the anchors in the current strengthening design codes of practice. For the aforementioned reasons, one-point loading tests were conducted on six shear deficient RC T-beams. Five specimens were strengthened with U-Wrapped CFRP laminates, four of which were anchored with different configurations of CFRP splay anchor systems, and one T-beam was left unstrengthened to serve as a benchmark specimen. The parameter investigated in this study is the anchor inclination angle. The angles examined are 0º, 25º, 45º, and 90º, respectively. Test results showed that the anchors delayed CFRP debonding, improved the shear strength, and significantly enhanced the ductility of the unanchored RC beam specimen. In addition, small anchor inclination angles performed better in terms of enhancing the shear strength and ductility of RC T-beams than perpendicular anchors. This study will contribute in the development of design recommendations of FRP anchor splay systems.