Failure mode-based calculation method for bending bearing capacities of normal cross-sections of corroded reinforced concrete beams

Abstract

This paper proposed a failure mode-based calculation method for bending bearing capacities of corroded reinforced concrete (RC) beams with corroded tensile steel bars and/or corroded compressive steel bars. Three balanced failures and corresponding three balanced corrosion ratios of tensile steel bars were identified. Based on three balanced corrosion ratios, four failure modes were identified and corresponding calculation methods for bending bearing capacities under different failure modes were proposed for corroded RC beams. Subsequently, the proposed calculation method, as well as modified conventional methods, was compared with tested ultimate bending moments of 421 corroded and 96 non-corroded control RC beams. Moreover, several examples were designed and calculated by the proposed method and modified conventional methods to illustrate the differences among different calculation methods. The comparisons and analyses showed that the bending bearing capacities predicted by the proposed method had good match with the test results in the full range of corrosion ratios of tensile steel bars, but the modified conventional methods theoretically remained valid only in partial ranges of corrosion ratios. The proposed failure mode-based calculation method will contribute to both accurate performance assessment of existing RC structures and efficient reliability analysis of new planned RC structures.