Analytical modeling of concrete columns confined by FRP

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Becque, Jurgen
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FRP-encased concrete columns benefit from a confining effect due to the restraint of the lateral expansion. This effect increases the strength and the ductility of the concrete inside the FRP shell. A number of empirical models predicting the behaviour of steel- and FRP-confined concrete have been presented in literature. However, a more accurate model for FRP-confined columns is needed. This thesis proposes a model for concrete columns confined by an FRP shell, where the axial load is applied to the concrete core only and the shell is used as a confining jacket. A second model is proposed for the case where both the FRP and the concrete carry the compressive axial load. The latter model is modified to include configurations with an inner centered void and configurations with a double shell. All of these models satisfy the conditions of equilibrium and strain compatibility between both materials. Also a finite element model for FRP-confined columns, based on the Drucker-Prager criterion, is presented. The proposed models are verified by comparing the predictions to experimental data published by different researchers, including an experimental program carried out at the University of Manitoba. The proposed models are used to examine the influence of key parameters, believed to determine the behaviour of composite sections.