Experimental Study on Shear Behavior of Reinforced-Concrete Members Fully Wrapped with Large Rupture-Strain FRP Composites

Abstract

Experimental study on shear behavior of reinforced concrete members fully wrapped with large rupture strain FRP composites This paper presents an experimental study on the shear behavior of reinforced concrete (RC) members fully wrapped with polyethylene terephthalate (PET) fiber reinforced polymer (FRP) composites, which are a new type of FRP material characterized with a much larger rupture strain (LRS) compared to conventional FRPs (i.e., made of carbon, glass, and aramid fibers). A total of ten PET fully-wrapped RC beams, which were designed to fail in shear and with different shear-span to effectivedepth ratios, transverse reinforcement ratios and shear strengthening ratios, were tested under four-point bending loads. The overall load-deflection responses and the shear deformation of the beams as well as the strain development of the transverse steel reinforcement and the FRP jackets were carefully observed. Based upon the extensive strain measurements, the shear contributions by concrete, FRP and transverse reinforcement are differentiated. It was found that the use of PET FRP composites as the jacket material of RC members can shift the mode of shear failure from a brittle one to an ideal ductile one while the ultimate state of the members is no longer caused by FRP fracture. In order to efficiently predict the shear strength of RC members wrapped by LRS FRPs, the effective strain in LRS FRPs and the degradation of concrete at the peak member shear strength must be appropriately considered. No.Have all the authors contributed to the study and approved the final version?All authors must have contributed to the study, seen the final draft of the manuscript, and accept responsibility for its contents. It is unethical to list someone as a coauthor who does not want to be associated with the study and who has never seen the manuscript.Yes.Was an earlier version of the paper previously considered and declined by ASCE?Declined manuscripts are sent through the review process again. If your manuscript has been submitted to us before under a different title, please provide that title in the space provided below. It is our policy to inform an editor that a manuscript has been previously reviewed, even when it has been reviewed by a different Division, Institute, or Council within ASCE.No. composites, which are a new type of FRP material characterized with a much larger rupture strain (LRS) 26 compared to conventional FRPs (i.e., made of carbon, glass, and aramid fibers). A total of ten PET fully-27 wrapped RC beams, which were designed to fail in shear and with different shear-span to effective-depth 28 ratios, transverse reinforcement ratios and shear strengthening ratios, were tested under four-point 29 bending loads. The overall load-deflection responses and the shear deformation of the beams as well as 30 the strain development of the transverse steel reinforcement and the FRP jackets were carefully observed. 31Based upon the extensive strain measurements, the shear contributions by concrete, FRP and transverse ...

Full-range FRP failure behaviour in RC beams shear-strengthened with FRP wraps

“…This phenomenon was first observed in FRP-wrapped columns under cyclic loading (Priestley et al, 1996;Priestley and Seible, 1995). More recently, the existence of this adverse shear interaction was clearly observed by Jirawattanasomkul Jirawattanasomkul et al (2013) in RC beams shear-strengthened by FRP wraps and by Chen et al (2016) in RC beams shear-strengthened with well-anchored FRP U-strips (failing by FRP rupture). Using accurately measured FRP strains, it was shown that the concrete shear contribution started to decrease while that of FRP was still increasing.…”

“…RC beams shear-strengthened with FRP side strips, or strengthened with U-strips predominantly fail due to the debonding of FRP strips from the beam sides (Chen and Teng, 2003a, b;). However, often the failure of RC beams shear strengthened with FRP wraps (Jirawattanasomkul et al, 2013; and in some cases with FRP U-jackets [e.g. FRP U-jackets with anchorage (Chen et al, 2016;Kim et al, 2014;Mofidi et al, 2012)], are due to the rupture of FRP, usually preceded by FRP debonding (Cao et al, 2005;.…”

“…When FRP with large rupture-strain (e.g. >6%) was used, shear contribution of concrete was found to degrade by 056.4%, depending on the amount of FRP used, shear-span to beam depth ratio, and the member size (Jirawattanasomkul et al, 2013).…”

Shaking Table Evaluation of Reinforced Concrete Bridge Columns Repaired Using Fiber-Reinforced Polymer Jackets

“…In the past three decades, the FRP repair and strengthening technique has been extensively used in practice and evaluated by many experimental research activities focusing on improving the confining properties, ductility and strength [9], [40], [42], [49]- [52], [54]. However, very limited experimental research has given attention to assessing the validity of FRP repair of RC bridge columns using the dynamic testing with shaking [28], [60]. To the best of author's knowledge no such dynamic load assessment exists in the literature considering the realistic combined effect of lateral and vertical ground motion excitations.…”

Effect of PET Wrapping on Shear Performance of Corroded Reinforced Concrete Columns

“…However, due to low fracturing strain capacity of conventional FRPs [around 1.5% for carbon FRP (CFRP), 2% for glass FRP (GFRP), and 3% for aramid FRP (AFRP)], the fiber materials tend to fail sooner due to fiber breakage, which causes a loss of confinement and hence the load-carrying capacity as well as the ductility potential. New fiber materials, such as polyacetal fiber (PAF), polyethylene naphthalate (PEN), and polyethylene terephthalate (PET), have properties of large fracturing strain and low stiffness in comparison to aramid, carbon, and glass fibers (Jirawattanasomkul, Dai, Zhang, Senda, & Ueda, 2013). Previous studies (Anggawidjaja, Ueda, Dai, & Nakai, 2006;Dai, Bai, & Teng, 2011;Dai, Lam, & Ueda, 2012) proved that concrete or RC members wrapped by PET and PEN fiber sheets with large fracturing strain could efficiently enhance the ductility of concrete or RC members, regardless of their low stiffness.…”