Experimental and numerical study on axial compression behavior of slender CFST columns with localized pitting corrosion damage

In order to investigate the axial compression behavior of slender circular concrete-filled steel tubes (CFSTs) with localized pitting corrosion damage, an experimental and numerical study was performed in this paper. In the experimental study, mechanically drilled cylindrical pits were employed to simulate localized pitting corrosion damage. Seven specimens were tested, with six specimens containing corrosion pits located at mid-height and one intact specimen. The experimental results showed that the localized pitting corrosion damage degraded the axial compression behavior of the specimens. Numerical models were developed and validated by the experimental results and used to consider the random characteristics of corrosion pits. A parametric analysis was then performed based on the validated numerical models. It was revealed that the ultimate strength of CFST was influenced by the location and dimensions of the pitting corrosion. Considering the random nature of localized pitting corrosion damage located at the midheight, practical calculation models for predicting the ultimate strength of CFSTs were put forward based on the methods provided in existing codes. On account of the obtained data pool, the predictions were verified against the results from the tests and parametric analysis. In addition, considering the random locations of the pitting region on the surface of the member, a method based on the controlling section was proposed to determine whether the corrosion should be considered and to calculate the ultimate strength.