Axial compressive behavior and design-oriented model for large-rupture-strain (LRS) FRP-confined concrete in rectangular columns

• Published in: Journal of Building Engineering 2023-09, Vol.75, p.106925, Article 106925
• Main Authors: Zeng, Jun-Jie, Liao, JinJing, Zhu, De-Hua, Li, Peng-Da
• Format: Article
• Language: English
• Subjects: Aspect ratio; Axial compression; Confinement efficiency; Design-oriented model; Polyethylene terephthalate (PET) FRP; Rectangular short columns
• ISSN: 2352-7102; 2352-7102
• DOI: 10.1016/j.jobe.2023.106925

Polyethylene terephthalate (PET) fiber-reinforced polymer (FRP) composites, which is a kind of low-carbon production and have a large rupture strain, may have prosperous application outlooks. PET FRP wrap has been explored as confining reinforcement for concrete, and the majority of investigations are limited to PET FRP-confined concrete in circular and square columns, whereas PET FRP-confined rectangular columns have barely been touched. To fill this research gap and gain a fundamental understanding of the confinement mechanism, comprehensive compressive tests on 36 columns were conducted in this study, in which the confinement thickness, cross-section aspect ratio, and specimen size were the focal points. All specimens exhibited a three-segment behavior (i.e., strain hardening-softening-hardening response). In addition, it is demonstrated that specimen size had an insignificant effect on the axial stress-strain response of small and medium columns with a height less than 400 mm, provided that their confinement levels were the same (or similar). Furthermore, the minimum effective confinement stiffness for PET FRP-confined rectangular columns to achieve sufficient confinement was 0.004, which was extracted from all available test results. A design-oriented model with improved performance was proposed and the simulated full axial stress-strain showed close agreements with the test results. •Axial compression tests on 24 PET FRP-confined concrete in rectangular columns.•The minimum confinement stiffness ratio for a sufficient confinement is 0.004.•The specimen size effect is not evident.•A design-oriented model is proposed and assessed to have improved accuracy.