Fatigue Performance of Corroded Reinforced Concrete Beams Strengthened with Carbon Fiber Reinforced Polymer Sheets

The paper presents the results of an experimental and analytical study on fatigue performance of corroded reinforced concrete (RC) beam strengthened with carbon fiber reinforced polymer (CFRP) sheets. Five beams were constructed. One specimen was strengthened and not corroded to serve as a reference; another four specimens were corroded and was strengthened with CFRP sheets. Five specimens were tested in fatigue. The results showed that corrosion of the main reinforcing bars can results in a significant reduction of fatigue life. Although CFRP strengthening improved the structural behavior of beams after corrosion and results in a longer fatigue life, it did not completely restore the strength lost because of corrosion or bring the fatigue life up to the level of the virgin beam unless a sufficient number of CFRP sheets are bonded to the beam to reduce the stress in corroded reinforcing bars to a level that will give the same fatigue life as the virgin beam. Steel bars obtained from tested beams after fatigue loading were tested in tension. The results showed that the yield strength, the ultimate strength and the ultimate elongation of the steel bar severely deteriorate and the yield plateau of steel bar almost disappears with the development of corrosion and the increase of fatigue damage.