Failure mode-based calculation method for bearing capacities of corroded RC columns under eccentric compression

Abstract

This paper proposed a failure mode-based calculation method for bearing capacities of corroded RC columns under eccentric compressive loads, which considered corrosion-induced mechanical property degradation of steel bars, cross-sectional reduction of steel bars and cross-sectional reduction of concrete. Through analyzing the stress and strain distributions over the normal cross-section, four balanced failures and six failure modes were identified for corroded RC columns under eccentric compressive loads. Balanced corrosion degrees were defined and methods to calculate them were proposed. Based on corrosion degree and balanced corrosion degrees, the failure mode of an eccentrically compressed corroded RC column could be predetermined in advance. Then, the methods to calculate the eccentric compressive bearing capacity under each failure mode were proposed. Subsequently, a dataset of eccentric compressive tests on 118 corroded and 27 non-corroded RC columns was established. The eccentric compressive bearing capacities calculated by the proposed failure mode-based method were found in good agreement with the test results, which demonstrated the validity of the proposed method. The failure mode-based calculation method will contribute to not only rapid and accurate performance evaluation of existing corroded RC columns, but also fast and efficient time-dependent reliability analysis for planned RC columns.