Torsional strengthening of reinforced concrete beams with externally bonded composites: A state of the art review

The use of externally bonded (EB) fiber reinforced composites to strengthen reinforced concrete (RC) structures has been explored extensively in recent decades. While many studies have been conducted on the flexural, shear, and axial strengthening of RC members, far fewer studies have been conducted on torsional strengthening. Thus, the knowledge on the behavior of RC members strengthened in torsion with EB composites is rather limited. The aim of this paper was to present a comprehensive review and evaluation of torsional strengthening of RC beams using EB composites. A detailed survey of the literature was conducted, and a database of experimental tests was developed. The database includes beams reinforced with EB fiber reinforced polymer (FRP) and EB fiber reinforced cementitious matrix (FRCM) composites. The effectiveness of the strengthening system was examined in terms of geometrical and mechanical characteristics of the RC beam, composite type, and composite wrapping configuration. Different modes of failure of the strengthened beams were also discussed. Additionally, analytical and numerical methods developed to predict the torsional response of RC beams strengthened with EB composites were summarized and discussed. Finally, design provisions were examined based on the knowledge gained from this study. (C)2019 Elsevier Ltd. All rights reserved.