Fatigue Crack Propagation of Notched Steel Rebar in RC Beams Repaired with Externally Bonded CFRP

Abstract

This paper presents the results of an experimental study on the fatigue performance of RC beams strengthened with different externally bonded carbon fiber-reinforced polymer (CFRP) systems. Seven specimens were fabricated; three had no CFRP, while the remaining four had one of two CFRP systems. The objective of the research reported in this paper was to determine the effect the CFRP repair had on the growth rate of a fatigue crack initiating from a notch in the tensile rebars. The steel reinforcement was selected for focus because similar studies have found this reinforcement to be the limiting fatigue component in RC beams. The experimental results reported in this paper showed an extended fatigue life and a slowed crack growth rate in specimens repaired with both CFRP systems. The crack growth rates were used to determine material constants for the Paris law, which describes growth of a stable fatigue crack. These results are then used to propose recommendations for design of CFRP repair systems for a specific fatigue life.