Stress-strain behavior of large-scale circular columns confined with FRP composites

For a reliable and efficient design of fiber reinforced polymer (FRP) wrapping reinforcement, an accurate stress-strain prediction of reinforced concrete (RC) columns confined with FRP composites is essential. The stress-strain characteristics of FRP-confined concrete have been extensively studied, testing small-scale cylindrical specimens. In this paper, the stress-strain response of axially loaded large-scale columns confined with FRP wrapping reinforcement is investigated. The effective circumferential FRP failure strain and the effect of increasing confining action on the stress-strain behavior of RC columns confined with FRP are examined. Different models for the prediction of the stress-strain behavior of FRP-confined concrete have been reviewed. The existing stress-strain models are applied to predict the stress-strain response of the experimental results presented in this study. A comparison between the experimental results and those predicted by the existing models are presented. Few of the available models that were derived based on small-size cylinders were found to accurately predict the stress-strain response of large-scale columns.