Shear transferring mechanism of the FPR-to-concrete bonded joint with end U-jacketing: A theoretical study

Abstract

Installation of fiber reinforced polymer (FRP) U-jackets is an effective method for improving the low utilization rate of the expensive FRP material in the application of flexural strengthening of the reinforced concrete (RC) beam. The stress transfer mechanism of the FPR-to-concrete bonded joint with end U-jacket still remains poorly understood. This study proposed a new analytical model to predict the interfacial debonding process and the load carrying capacity of the joint with end U-jacket. The failure process of the FRP-to-concrete joint with an inclined U-jacket features five stages including elastic, elastic-softening, elastic-softening-debonding, softening-debonding and completely debonding stages. Expressions for the interfacial shear stress distribution and load–displacement relation are derived for these five stages. The load–displacement curve predicted by the analytical model, indicating that the bearing capacity of the joint with end U-jacket has increased by 200%, is in good agreement with the experimental and FE analysis results. Finally, the results from analytical solutions are presented to clarify the effects of the bond length, the FRP plate stiffness and the elasticity coefficient of end U-jacket on the load–displacement relations, the ultimate load and the effective bond length.