New Anchorage Technique for FRP Shear-Strengthened RC T-Beams Using CFRP Rope

Abstract

This study investigates the effectiveness of a new anchorage technique for fiber-reinforced polymer (FRP) shear-strengthened reinforced concrete T-beams using carbon fiber-reinforced polymer (CFRP) ropes. The rope is a bundle of flexible CFRP strands held together using a thin tissue net. In this technique, holes are drilled through the web at the web-flange intersection, where the CFRP ropes are inserted and flared onto the two free ends of the U-wrap scheme. This converts the U-wrap scheme to a full-wrap scheme. The experimental program includes three series based on the number of steel stirrups. No steel stirrups are provided in the first series, whereas the spacing between steel stirrups is 260 and 175 mm in the second and the third series, respectively. Each series includes a control specimen, with no external CFRP for shear strengthening, a specimen strengthened with CFRP sheets, a specimen strengthened with CFRP L-strips, and a specimen strengthened with CFRP L-strips and anchored with CFRP ropes. Two strengthening procedures are used in this study to investigate the effect of the FRP-width to concrete-width ratio. In the anchored specimens, the CFRP rope covers half the depth of the L-strips. The results of this study reveal that the beams anchored with CFRP ropes achieve an enhanced contribution to the shear resistance compared to the beams with CFRP sheets and CFRP L-strips with no rope. In addition, the method eliminates CFRP debonding and achieves rupture of steel stirrups.