Mechanical Behavior of CFRP Composites in Confined Concrete Columns

Fiber orientation is one of important parameters that affect strength and ductility of FRP-confined concrete columns. A number of studies have conducted on various fiber orientations and wrap thicknesses, but have not carried out a comprehensive study on tensile properties of FRP with various fiber orientations and their effects on confined concrete. In aerospace applications, significant researches have shown nonlinear behaviors in the off-axis direction in FRP structures. This paper presents the results of experimental studies about mechanical properties of high-strength carbon fiber reinforced polymer (CFRP) composites. In this study, 24 coupons of CFRP composites were tested in axial tension under displacement control mode. Eight ply configurations were prepared with fibers oriented at 0, ±45 and 90 from the axial direction and with 1, 2, 3 or 4 plies. It was found that stress-strain behavior is basically depended to fiber orientation. The behavior at pure longitudinal or matrix direction shows perfectly linear-elastic with brittle rupture, but at pure angle orientations is fully nonlinear and closed to elastic-perfect plastic with high ductility. At combination of longitudinal and angle orientations, the stress-strain curve shows a nonlinear behavior up to a maximum strength, and then down to a ductile failure with a nonlinear softening.

کلیدواژه ها:

Experimental study ، CFRP ، fiber orientation ، strengthening ، concrete column