Experimental Study on Compressive Response of Large Rupture Strain FRP Confined Reinforced Concrete

Abstract

External confinement of fiber-reinforced polymer (FRP) composites can effectively control the unstable concrete dilation. However, presence of internal steel reinforcement, particularly poorly detailed, can limit the efficiency of FRP confinement by imposing high stress concentrations due to buckling of the longitudinal bars. The adverse effect of bar buckling can be mitigated by delaying the premature FRP rupture to high strain levels using confining materials with a large rupture strain (LRS) capacity. In this paper, experimental results on the compressive response of poorly detailed reinforced concrete (RC) column specimens externally confined with polyethylene terephthalate (PET) FRP, which possesses an LRS, are presented. Experimental results indicated that buckling of steel bars in specimens was a noticeable event. The results also indicated the high efficiency of PET FRP in controlling the unstable dilation of confined concrete with internal steel reinforcement. Furthermore, PET FRP efficiently sustained the local stress concentrations due to bar buckling and redistributed the internal concrete damage, which makes it an attractive option for seismic retrofitting.