Axial compressive behavior and stress-strain model analysis of FRP-confined corroded RC columns with different-sized circular sections

Abstract

Compared to the non-corroded counterparts, very few studies have focused on the size effect on the mechanical performance and stress-strain behavior of FRP-confined corroded RC columns. To fill this research gap, this paper experimentally studied the axial compressive behavior and stress-strain response of several CFRP-confined corroded RC columns with different-sized circular sections. 96 circular RC columns were designed and the critical test parameters mainly included the column size, corrosion rate, and the number of CFRP layers. Subsequently, the effects of corrosion rate, the number of CFRP layers, and size effect on the failure modes, load-displacement curves, stress-strain curves, ultimate conditions, and FRP confining efficiency of the specimens were extensively examined. The results indicated that there was no significant size effect on the stress-strain behavior of FRP-confined corroded concrete (i.e., the damaged concrete due to rebar corrosion), but it would be more pronounced when the specimen size was small and the columns were under higher corrosion rates. In addition, by incorporating the influence of rebar corrosion on the damage of concrete and FRP confining efficiency, this study proposed the improved stress-strain models for FRP-confined corroded concrete and the analytical ultimate axial load model for the FRP-confined corroded RC columns. It is observed that the proposed models could yield better prediction results than the existing models available in the literature.