Numerical study and seismic design of corroded circular RC columns strengthened by C-FRCM

Abstract

This study aims to numerically investigate the behaviour of corroded circular reinforced concrete (RC) columns strengthened by carbon-fabric-reinforced cementitious matrix (C-FRCM) composites. Three-dimensional finite element (FE) models of the corroded circular RC columns with and without strengthening were set up and validated against previous experimental results. Based on the validated FE models, the parametric studies were carried out to investigate the effects of axial compression ratio, degree of corrosion and layer of carbon fabrics on the behaviour of corroded RC columns under cyclic loading. It shows that the lateral load resistance increased when the axial compression ratio ranged from 0.3 to 0.4, but decreased when the axial compression ratio ranged from 0.4 to 0.6; also the ductility of the corroded RC columns reduced with increasing axial compression ratio. The ultimate capacity of corroded RC columns decreased gradually with the increasing degree of corrosion. Based on the results of parametric studies, equations were developed to estimate the ultimate capacity and displacement of the corroded RC columns repaired by the C-FRCM. The proposed equations can well estimate the ultimate lateral load resisting capacity and ultimate displacement of the corroded circular RC columns strengthened by C-FRCM.