Compressive Behavior of Large-Scale PEN and PET FRP–Confined RC Columns with Square Cross Sections

Abstract

This paper presents results of a first-ever experimental study on the axial compressive behavior of large-scale square reinforced concrete (RC) columns confined with polyethylene naphthalate (PEN)/terephthalate (PET) fiber–reinforced polymer (FRP) composites, which is a new type of FRP with a large rupture strain (LRS) of over 5%. In total, 10 large-scale square RC columns were tested under axial compression, including 8 LRS FRP–wrapped RC columns and 2 RC columns, which served as control specimens. The key experimental parameters were the sectional corner radius and the thickness and type of LRS FRP. The test results show that the effective confinement stiffness ratio of an FRP jacket, as determined by the corner radius and FRP thickness, has a significant effect on the axial compressive behavior of LRS FRP–jacketed large-scale square RC columns. Based on the experimental results, this paper presents an evaluation of two existing LRS FRP–confined concrete models for noncircular columns. Finally, based on the test findings, a refined model for LRS FRP–confined large-scale square columns is presented to provide more accurate predictions of the compressive behavior of these columns.