FRP-confined concrete in circular sections: Review and assessment of stress-strain models

This paper presents the results of a recent study conducted to refine the design-oriented stress–strain model originally proposed by Lam and Teng for fiber-reinforced polymer (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 writers’ 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 present...

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Refinement of a design-oriented stress-strain model for FRP-confined concrete

A large number of experimental studies have been conducted over the last two decades to understand the behavior of FRP-confined concrete columns. This paper presents a comprehensive test database constructed from the results of axial compression tests on 832 circular FRP-confined concrete specimens published in the literature. The database was assembled through an extensive review of the literature that covered 3042 test results from 253 experimental studies published between 1991 and the middle of 2013. The suitability of the results for the database was determined using carefully chosen selection criteria to ensure a reliable database. This database brings reliable test results of FRP-confined concrete together to form a unified framework for future reference. Close examination of the test results reported in the database led to a number of important observations on the influence of important parameters on the behavior of FRP-confined concrete. A new design-oriented model that was developed to quantify these observations is presented in the final part of the paper. It is shown that the predictions of the proposed model are in close agreement with the test results and the model provides improved predictions of the ultimate conditions of FRP-confined concrete compared to any of the existing models.

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Axial compressive behavior of FRP-confined concrete: Experimental test database and a new design-oriented model

Effect of cross-sectional aspect ratio on the strength of CFRP-confined rectangular concrete columns

Unified stress–strain model of concrete for FRP-confined columns

In this paper, a stress–strain model for concrete confined by fiber reinforced polymer (FRP) composites is developed. The model is based on the results of a comprehensive experimental program including large-scale circular, square and rectangular short columns confined by carbon/epoxy and E-glass/epoxy jackets providing a wide range of confinement ratios. Ultimate stress, rupture strain, jacket parameters, and cross-sectional geometry were found to be significant factors affecting the stress–strain behavior of FRP-confined concrete. Such parameters were analyzed statistically based on the experimental data, and equations to theoretically predict these parameters are presented. Experimental results from this study were compared to the proposed semi-empirical model as well as others from the literature.

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Marwan N. Youssef

Papers

Stress-strain model for concrete confined by FRP composites