Influence of free edge stress concentration on effectiveness of FRP confinement

The use of fiber-reinforced polymers (FRP) composite materials have been widely used and have been extensively studied in the last decades in the form of jacketing to enhance axial strength as well as ductility of confined columns. Their effectiveness has been extensively proven in many research programs investigating confined concrete column behavior. Despite a large research effort, a proper analytical tool to predict the behavior of FRP-confined concrete has not yet been established due to the many factors jeopardizing the reliability of such tools. The aim of the present study is to analyze the effect of interlaminar stresses at the free edge of the FRP jacket to determine a potential reason for the premature failure of the strengthening system. Numerical examples and a parametric study are presented to illustrate the governing parameters that control the stress concentrations at the edge of the FRP jacket in the overlapping zone.