Structural Performance of RC Beams Strengthened with Prestressed Near-Surface-Mounted CFRP Tendons

Abstract

This paper describes how fiber reinforced polymer (FRP) composites have been widely used as externally bonded reinforcements to strengthen or rehabilitate deteriorated concrete structures. However, premature debonding failure, due to the limitation of bond at the FRP-concrete interface,is often encountered, which limits FRP material potential for flexural strength increase. In order to minimize debonding failures and mechanical damage such as vehicular traffic and impact, etc., near surface mounted (NSM) FRP technology has emerged as another structural rehabilitation method. This study aims at evaluating a new strengthening using prestressed NSM carbon fiber reinforced polymer (CFRP) tendons. Although NSM FRP tendons are less susceptible to debonding than externally bonded FRP laminates, the load-carrying capacity of RC structures with NSM reinforcements is still likely to be governed by “premature” debonding failure. An experimental program with design variables such as prestress level and bonding agents was carried out to study the strengthening performance in terms of stiffness, cracking behavior and load-carrying capacity. The experimental results are presented and discussed in this paper. Experimentally validated bonding method is also proposed in this study.