Eccentricity-based design-oriented model of fiber-reinforced polymer-confined concrete for evaluation of load-carrying capacity of reinforced concrete rectangular columns
This study aimed to evaluate the load-carrying capacity of reinforced concrete rectangular columns confined with fiber-reinforced polymer composites and subjected to small eccentric loading. Seven design-oriented models of fiber-reinforced polymer-confined concrete were implemented in OpenSees software to establish the theoretical axial force-moment interaction diagram for rectangular columns. The examined models were categorized into two types: stress–strain models developed for fiber-reinforced polymer-confined non-circular concrete tested under the effect of concentric loading and others designed for fiber-reinforced polymer-confined non-circular concrete subjected to eccentric loading. The accuracy of these models was examined against the experimental results of eccentrically loaded fiber-reinforced polymer-confined reinforced concrete rectangular columns. Results indicated that the local stress–strain law obtained from the concentric compression tests would not reflect very well the local behavior of the compression zone of fiber-reinforced polymer-reinforced concrete members subjected to the combined effect of flexural and axial loadings. Adoption of a rational approach reflecting the impacts of eccentric loadings on the stress–strain relationship of the fiber-reinforced polymer-confined concrete revealed a much better evaluation of the load-carrying capacity of both reinforced concrete rectangular columns and plain concrete square columns under the effect of axial loads with various eccentricities.