Meso-scale analysis of shear performance and size effect of CFRP sheets strengthened RC beams

Abstract

In order to reflect and reveal the shear failure process and mechanism of carbon fiber reinforced plastic (CFRP) sheets strengthened reinforced concrete (RC) beam, a mechanical analysis model is established by using a 3D meso-scale simulation method. The model considers the heterogeneity of concrete materials, the interaction behaviors between reinforcements and concrete, and the complex interaction behaviors between CFRP sheets and concrete, simultaneously. Different types of meso-scale models of RC beam strengthened with CFRP sheets are designed to explore the influences of stirrup ratio and CFRP fiber ratio on the nominal shear strength and size effect behaviors. Test results indicate that: 1) The action mechanisms of stirrups and CFRP sheets are similar; 2) The nominal shear strength of CFRP sheets strengthened RC beams increases with the increase of stirrup ratio and CFRP fiber ratio, while the degree of the increasing range decreases; 3) The nominal shear strength of RC beams strengthened with CFRP sheets decreases with the increase of section size, nevertheless increasing the stirrup ratio and the CFRP fiber ratio will weaken the size effect; 4) Based on the numerical test results, a novel size effect law simultaneously considering the stirrup ratio, the CFRP fiber ratio and the mutual effects between them is proposed.