Fatigue properties of RC beams reinforced with ECC layer and steel plate

Pasting steel plates on the tensile side of reinforced concrete (RC) beams to improve their flexural capacity is a standard strengthening method. However, the increase in the RC beam bearing ability is limited, and it is easy to induce “over-reinforced beam” failure. In this paper, therefore, the ECC layer and steel plate are employed for the flexural strengthening of RC beams and the static, and fatigue properties of RC beams are investigated through experiments. A total of seven test beams were made. The static failure test and fatigue performance test were conducted to measure the ultimate bearing ability, flexibility, strain of steel and concrete, mid-span deflection, and residual bearing ability of the three kinds of RC beams after specific fatigue times. The experimental results demonstrate that the flexural capacity of the RC beam with the ECC layer and steel plate is more than twice that of the non-reinforced beam, and its flexibility is 1.77 times that of the non-reinforced beam. The residual bearing ability is 96.2% of the static loading test after 200 thousand times of fatigue loading. Additionally, no apparent damage occurs after 2 million times of fatigue loading, and the residual bearing ability is 94.2% of the static loading test. The strain range of the tensile rebar and concrete of the beam reinforced with the ECC layer and steel plate significantly decrease. Thus, RC beams reinforced with the ECC layer and steel plate possess a good fatigue performance.