Local and post-buckling behavior of corroded axially-compressed steel columns

To investigate the effect of corrosion on the local and post-buckling behavior of axially-compressed steel members, H-shaped Q345B steel columns with different corrosion degrees were obtained by accelerated corrosion test. Then, an axial compression test was performed to analyze the relationships between the failure mode, local buckling load, and ultimate load and the corrosion degree. Finally, more than 80 finite element models of steel columns with different corrosion parameters were established in the software ABAQUS, and a modified direct strength method for corroded axially-compressed steel stub columns considering local buckling was proposed. The results showed that the axial-load capacity of the axially-compressed steel column decreased gradually with the increased degree of corrosion. The yield load, ultimate load and local buckling load of the most seriously corroded specimen decreased by 15.0%, 18.9% and 21.4%, respectively. The corrosion changed the failure modes of specimens and gradually decreased the half-wavelength, which weakened the plastic deformation capability of specimens and led to the failure mode of the steel columns transforming from strength failure to stability failure. In addition, the corrosion pits had less of an effect on the axial-load capacity of specimens than the thickness loss. Under the same corrosion type, the location and size of the corrosion would not affect the ultimate load of the axially-compressed members, which only depended on the damage degree of weakest section. Finally, the proposed formula can accurately predict the post-buckling behavior and ultimate load of corroded H-shaped axially-compressed steel columns by comparing the experimental data with the finite element results and the results in the existing literature.