Fatigue Behavior of Reinforced Concrete Beams Strengthened with Different FRP Laminate Configurations

Synopsis: This paper presents testing results of thirteen small-scale beams strengthened using carbon fiber-reinforced polymer composites tested under repeated loads to investigate their fatigue behavior. The beams were strengthened using different thicknesses and widths of composite laminates to identify parameters that would generate different failure modes. Two predominant fatigue failure modes were identified through these tests: fatigue fracture of the steel reinforcement with subsequent debonding of the composite laminate, or fatigue fracture of the concrete layer below the tension reinforcing steel (concrete peel off). Test results indicate that peak stress applied to the reinforcing steel in combination with composite laminate configuration are the main parameters that affect the controlling failure mode. Tests on large-scale components are required to verify the results presented in this paper.