Behavior and modeling of fiberreinforced polymer-confined concrete in elliptical columns

Conversion of rectangular columns into elliptical columns (i.e. shape modification) followed by fiber-reinforced polymer jacketing provides an attractive alternative strengthening method than direct fiber-reinforced polymer jacketing of rectangular reinforced concrete columns (with corner rounding). For this method to be widely used in practice, a design method for the fiber-reinforced polymer jacket needs to be developed, and the key to such a design method is a reliable and yet relatively simple stress–strain model for fiber-reinforced polymer-confined concrete in elliptical reinforced concrete columns. This article presents a combined experimental and finite element study from which a stress–strain model for fiber-reinforced polymer-confined concrete in elliptical columns was derived. The article first presents the experimental program designed to examine the effects of key parameters. The accuracy of a finite element model for fiber-reinforced polymer-confined elliptical concrete columns is then demonstrated through comparisons with the test results. Finally, on the basis of the test data as well as the numerical results obtained with the verified finite element model, a simple and accurate stress–strain model for fiber-reinforced polymer-confined concrete in elliptical columns is formulated for use in design.