Use of grooving method for shear strengthening of RC beams with UHPFRC panels

Abstract

The aversion of sudden shear failure in reinforced concrete (RC) beams and structures requires effective strengthening methods. This study investigated the efficacy of precast ultra-high-performance fiber-reinforced concrete (UHPFRC) panels for shear strengthening of RC beams. The focus was on the effect of concrete surface preparation on strengthening. The grooving method (GM), specifically the externally bonded reinforcement on grooves (EBROG) technique, has been proposed as an alternative to the EBR method. Experimental results from four-point loading tests on five RC beams revealed that the EBROG method significantly increased the load-carrying capacity and energy dissipation over that of the EBR method. Optimized groove classes and appropriate groove angles further improved its performance, transitioning failure modes and debonding mechanisms. The EBROG method increased the beam ultimate load 1.78-fold and energy dissipation 11.36-fold compared to the control specimens. The failure modes transitioned from shear to flexure-shear, and the debonding modes shifted from surface to deep debonding. An analytical approach is developed to predict the shear capacity, incorporating panel properties and installation methods. This research underscores the potential of UHPFRC panels and the EBROG technique for effective shear strengthening of RC structures.

Keywords

• RC beams
• Shear strengthening
• UHPFRC panels
• Grooving method
• Groove classes