Model uncertainty in the estimation of the resistance of circular reinforced concrete columns confined by carbon fiber reinforced polymer

摘要

Utilisation of carbon fibre-reinforced polymers (CFRP), for confinement of concrete, has proved to be a viable alternative in the strengthening of reinforced concrete (RC) columns with circular cross-sections. However, a large research effort is still necessary in order to select analytical models that properly estimate the ultimate strength and strain of RC columns confined by FRP and transversal steel (FRP-RC). Different models have been proposed, but most of the available FRP-confinement models have been validated by experimental results of cylinders of plain concrete, not taking into account the influence of longitudinal and transversal steel which occurs in the strengthening of existing RC columns. The statistical description of the model error', representing uncertainty in the prediction of column resistance, is required information in the reliability analysis of FRP-RC columns. In this study, four representative confinement models are evaluated. A comprehensive experimental database encompassing RC columns with longitudinal and transversal steel confined by CFRP is compiled from the literature. A statistical analysis is performed in order to describe the model errors associated to the estimation of ultimate stress, (f), and ultimate strain, (epsilon). For the confinement models considered in this work, the coefficients of variation are in the range 0.23-0.49 ((f)) and 0.54-1.43 ((epsilon)).