Modeling of size effect on compressive behavior of CFRP-confined rectangular RC columns: Influence of corner radius and aspect ratio

Abstract

Taking into consideration the concrete heterogeneity, a three-dimensional meso-scale approach was established to model the failure of axially loaded rectangular reinforced concrete (RC) columns confined with carbon FRP (CFRP). This meso-scale method was first verified by the available test data. The investigation on the influences of edge sharpness from 0.07 to 0.20 and aspect ratios of 1.0, 1.5 and 2.0 on compressive behavior of CFRP-confined rectangular RC columns with different cross-sectional heights (300 mm, 600 mm, and 900 mm) was performed using the verified numerical model. Similar failure model was observed from the geometrically-similar columns, while a significant size effect was exhibited in the compressive strength. As the structural size increased, the effective confinement area ratio calculated from axial stress distribution decreased, illustrating that the confinement of CFRP jackets on concrete existed a size effect. Moreover, as the edge sharpness increased, the size effect on confinement was weakened, and this weakening effect was reduced with the aspect ratio increasing. Finally, considering the influence of the new arch action model and structural size, a modified model was proposed to predict compressive strengths of rectangular RC columns strengthened with CFRP.