TIME-VARYING BEARING CAPACITY EVALUATION OF BRIDGE UNDER COUPLING ACTION OF CORROSION AND FATIGUE

For the reinforced concrete bridges, the degeneration phenomenon such as corrosion, bond degradation and fatigue damage will occur under the double action of environmental effect and loading. The comprehensive action of the three factors cannot be entirely considered according to the current bearing capacity calculation methods. The influence of corrosion, bond degradation and fatigue damage on the bearing capacity of RC bridge was intensively elaborated based on the existing achievements, and the reduction of reinforcement area under the coupling action of corrosion and fatigue was analyzed. The analytic expression of cross section cooperative work coefficient was deduced according to the deformation coordination relationship between corroded steel bar and concrete interface, and the bearing capacity calculation method considering corrosion, bond degradation and fatigue damage was proposed. Taking one reinforced concrete simply supported beam as an example, the degradation process of bearing capacity was analyzed by the finite element method and the theoretical method proposed in this study, respectively. The results show that the evaluation method of bearing capacity considering coupling effects can reasonably represent the degradation process of bearing capacity under the action of fatigue and corrosion. The new method can be used as an effective reference for evaluating the bearing capacity of RC bridges under the coupling action due to corrosion and fatigue.