Fracture mechanics based calculation model of flexed RC elements strengthened with FRP

Abstract

In this paper calculation model of RC structures strengthened with prestressed and not prestressed various EB and NSM FRP reinforcements have been presented. Proposed model is based on the theory of fracture mechanics of solids. The science of fracture mechanics could be used for the analysis of the fracture development in flexural reinforced concrete beams. The critical parameters of normal cracks caused by stress state are used for such analysis. The numerical results are compared with experimental ones. 71 RC beams, strengthened with CFRP and GFRP sheets, plates, strips and rods, mounted by EBR or NSM methods, are analysed in this comparison. Experimental results were collected from various scientific publications. The reduction of overall member stiffness because of the slip between concrete and FRP was estimated by reducing the FRP stress in accordance with built-up bars theory.