Fatigue Behavior of Cracked Steel Beams Reinforced by Using CFRP Materials

Carbon Fiber Reinforced Polymer (CFRP) strips externally bonded on a damaged steel beams are effective under monotonic loads. Less information is available on the fatigue behavior. Experimental tests were then performed at the Politecnico di Milano on flexural strengthening of cracked steel beams with CFRP strips of different thickness. The results in term of fatigue crack propagation curves showed that CFRPs bonded around the tip zone reduce the fatigue crack growth and extend the fatigue life. In addition, high strain concentration was recorded in the CFRP strip close to the cracked section. This indicates that the cracked zone is a potential debonding area of the CFRP strips from the steel substrate.