Design-oriented stress-strain model for FRP-confined concrete in rectangular columns

The behavior of fiber reinforced polymer (FRP)-confined concrete in circular columns has been extensively studied, but much less is known about concrete in FRP-confined rectangular columns in which the concrete is nonuniformly confined and the effectiveness of confinement is much reduced. This paper presents a simple design-oriented stress-strain model for FRP-confined concrete in rectangular columns. To this end, existing theoretical models are first reviewed. A database of existing test results collected by the authors is next presented, which is then augmented by a new set of results from tests conducted by the authors. The augmented test database is next employed to assess the existing theoretical models. Finally, a stress-strain model is presented, which is an extension of a recent design-oriented stress-strain model developed for concrete uniformly-confined with FRP based on test results of circular concrete specimens. The proposed stress-strain model is shown to provide satisfactory predictions of the stress-strain curves obtained from the authors' new tests.