DEFLECTION CALCULATION OF REINFORCED CONCRETE BEAMS UNDER CORROSION-FATIGUE COUPLING ACTION

Three sets of corrosion-fatigue coupling bearing tests of reinforced concrete (RC) beams under different stress amplitudes are designed to study the structural mechanical behavior and stiffness degradation of reinforced concrete beams under corrosion-fatigue coupling effect, and the fatigue life and stiffness evolution law of each test beam are analyzed as well. The results indicate that, the coupling effect of corrosion and fatigue reduces the fatigue life of reinforced concrete members, and the deflection development curves of fatigue beams and corrosion-fatigue coupled beams both show a 'sudden increase-stable-sudden increase' change law. And the deflection development rate in the second stage is much larger than that of the fatigue-loaded beam under the same stress amplitude. On the basis of existing codes, the stiffness calculation method of existing fatigue beams and corrosion-fatigue coupled beams is improved. The proposed method systematically considers the effects of fatigue, stress amplitude, concrete elastic modulus degradation and steel corrosion. And a good agreement is observed between theoretical results and experimental values, which verifies the accuracy of the stiffness calculation model.