Hybrid and patch anchors for prevention of IC debonding in RC planks flexurally strengthened using FRP

Abstract

One of the predominant failure modes of reinforced concrete (RC) members strengthened in flexure using fiber reinforced polymers (FRP) is intermediate crack induced (IC) debonding.This failure mode is usually brittle, premature and constitutes a significant underutilisation of the FRP material. To address this type of failure, design guidelines enforce strict limitations on the allowable FRP strain level which can be used in design. In order to suppress IC debonding failure modes, researchers have explored various anchorage systems with varying degrees of success. This paper investigates the use of patch anchors and hybrid anchors to suppress IC debonding failure. An experimental program is presented where RC planks are strengthened with FRP laminates and sheets and anchored using different arrangements. The results show that the addition of two hybrid anchors to the ends of the FRP plate results in significant load and deformation increases compared with unanchored planks.