A new flexural strength model of CFRP-strengthened RC beams with intermediate crack induced debonding failure. (15th March 2023)

• Record Type: Journal Article
• Authors: Li, Guibing; Zhang, Aihui; Jin, Weiliang; Xiao, Yifei; Li, Huaying
• Is Part Of: Composite structures. Volume 308(2023)
• Publication Date: 2023-03-15
• Subjects: RC beam -- CFRP -- IC-induced debonding -- CFRP strain -- Flexural strength -- Debonding strain limit; Composite construction -- Periodicals; Composites -- Périodiques; 624.18
• DOI: 10.1016/j.compstruct.2023.116681
• Languages: English
• ISSNs: 0263-8223

Abstract

Abstract: The ACI440.2R and other codes advice that the concrete can reach the compressive strain of 0.003 and there is no FRP debonding at the ultimate limit state of FRP-strengthened RC beams. However, many flexural tests have shown that intermediate crack (IC) induced debonding is the main failure mode of FRP-strengthened RC beams and the ultimate compressive strain of the concrete cannot reach 0.003, in most cases, even much less than 0.003 at initial debonding of CFRP reinforcements. Moreover, the FRP debonding strain limit proposed by the codes can not effectively prevent debonding failure. This study takes the initial debonding as the ultimate limit state of CFRP-strengthened RC beams with IC debonding failure, and then develops a new model for calculating CFRP strain and flexural strength according to the theoretical analysis and test results. Six CFRP-strengthened RC beams are tested to investigate the initiation of CFRP debonding in order to get clear pictures of the tensile strains in CFRP reinforcements, load-carrying capacity, concrete compressive strain, and cracks at the initial debonding. The new model is able to provide a more accurate evaluation of the CFRP strain and flexural strength of CFRP-strengthened RC beams with IC debonding failure than code models.