Fatigue Bond Stress-Slip Behavior of Lap Splices in the Reinforcement of Unwrapped and FRP-Wrapped Concrete Beams

This paper presents an experimental study on the effect of fiber-reinforced polymer (FRP) wrapping on the fatigue performance and bond strength of reinforced concrete beams containing a lap splice at a constant moment region under cyclic loading. In addition, the study presents the slip response of the steel bars. Fifteen beams were investigated that were divided into three groups, namely: unwrapped, glass fiber-reinforced polymer (GFRP) wrapped, and carbon fiber-reinforced polymer (CFRP) wrapped. The test variables were the presence or absence of FRP wrapping, the type of the FRP wrapping (GFRP or CFRP), the type of loading (monotonic or fatigue loading), and the fatigue load range. The results of the tests under monotonic load showed a significant increase in load and deflection for the FRP-wrapped beams compared to the unwrapped beams. The increase in the unwrapped beams load deflection results for the CFRP-wrapped beams was greater than that for the GFRP-wrapped beams. Also, the FRP-wrapped beams had higher fatigue strengths than the unwrapped beams. The bond stress slip response under monotonic and fatigue loading is compared. (C) 2016 American Society of Civil Engineers.