Bending Capacity Calculation Method for Corroded Reinforced Concrete Beams

The corrosion state of longitudinally stressed steel bars in corroded reinforced concrete beams is very complicated. Moreover, the form of the load applied to beams is variable. In order to obtain the bending capacity of corroded RC (reinforced concrete) beams, the corroded RC beam with simple support is taken as the object, which is regarded as a composite beam composed of steel bars and concrete with bond and slip. Based on the deformation coordination conditions between corroded steel bars and concrete, the equilibrium differential equation of corroded reinforced concrete beam is expressed by deflection. By the homogeneous solution of the differential equilibrium equation that is used as the unit shape function, the element stiffness matrix, the equivalent node load matrix, and the internal force calculation formula of the corroded reinforced concrete beam is derived under each load step. The calculation method for the bending capacity of corroded reinforced concrete beams which can reflect the corrosion condition of the steel and the load form is established. The analytical method is validated with the test data of 17 corroded reinforced concrete beams. The average ratio of test results to predicted results is 1.06 and the variance is 0.012, which shows good agreement between test and prediction results, and desirable accuracy of the calculation method.