No abstract

No abstract

No abstract

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 designoriented 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.

No abstract

No abstract

Many stress-strain models have been developed for fibre-reinforced polymer (FRP)-confined concrete. These models fall into two categories: (a) design-oriented models in simple closed-form expressions for direct use in design; and (b) analysis-oriented models in which the stress-strain curve is generated via an incremental process. This paper is concerned with analysis-oriented models, and in particular, those models based on the commonly accepted approach in which a model for actively-confined concrete is used as the base model. The paper first provides a critical review and assessment of existing analysis-oriented models for FRP-confined concrete. For this assessment, a database of 48 recent tests conducted by the authors' group is presented; this database includes 23 new tests which have not previously been published. This assessment clarifies how each of the key elements forming such a model affects its accuracy and identifies a recent model proposed by the authors' group as being the most accurate. The paper then presents a refined version of this model, which provides more accurate predictions of the stress-strain behaviour, particularly for weakly-confined concrete.

This paper presents the results of a recent study conducted to refine the designoriented stress-strain model originally proposed by Lam and Teng for FRP-confined concrete under axial compression. More accurate expressions for the ultimate axial strain and the compressive strength are proposed for use in this model. These new expressions are based on results from recent tests conducted by the authors' group under well-defined conditions and on results from a parametric study using an accurate analysis-oriented stress-strain model for FRP-confined concrete. They allow the effects of confinement stiffness and the jacket strain capacity to be separately reflected and accounts for the effect of confinement stiffness explicitly instead of having it reflected only through the confinement ratio. The new expressions can be easily incorporated into Lam and Teng's model for more accurate predictions. Based on these new expressions, two modified versions of Lam and Teng's model are presented. The first version involves only the updating of the ultimate axial strain and compressive strength equations. The second version caters for stress-strain curves with a descending branch, which is not covered by the original model. This is the Pre-Published Version.