FRP-CONFINED RC COLUMNS UNDER COMBINED BENDING AND COMPRESSION: A COMPARATIVE STUDY OF CONCRETE STRESS-STRAIN MODELS

摘要

Many stress-strain models have been proposed for FRP-confined concrete, but there is still a lack of consensus as to which model is the most suitable for use in the analysis of RC columns confined by FRP jackets. In this paper, different stress-strain models are compared in terms of their predictions of the ultimate strength and the flexural ductility of FRP-confined RC short columns subject to combined bending and axial compression. These comparisons show that the predicted ultimate strength depends mainly on the compressive strength of the confined concrete model while the predicted ultimate curvature depends mainly on the ultimate strain of the confined concrete model. For design use, a stress-strain model with a lower bound prediction of the ultimate strain of confined concrete should be used so that conservative predictions of flexural ductility can be expected, while the predictions of the ultimate strength are similar to those predicted using a best-fit value of the ultimate strain.