Effects of uniformly distributed side corrosion on thin-walled open cross-section steel columns

Abstract

Compressive capacity of the thin-walled steel columns, corroded uniformly over their entire side surface length is analysed in this paper. The thin-walled profile steel columns are often used for bridges, rail and road building constructions. Loss of the profile mass that appears due to corrosion growth reduces the cross-sectional area and influences column compressive capacity. Computational models of the structure are assumed based on the observation of existing corroded columns. The theory of thin-walled profiles is taken for the analysis. Models simulating the walls weakening due to corrosion growth are considered on the example of three thin-walled steel profiles: semi-closed channel section, two semi-closed channel section connected by webs and HKS profiles. Different patterns and degrees of corrosion growth were considered and, as a result, changes of the profile cross-sectional geometry were observed. Theoretical considerations of thin-walled compressed corroded steel columns stability are illustrated by bearing capacity calculations. Geometric cross-sectional characteristics are determined and the system of stability equations is solved. The calculation results are presented in the form of graphs illustrating the effects caused by the geometry change due to corrosion defects. The reduction of column compressive strength in each of the considered case is observed. Moreover a variation of the buckling mode from flexural one into warping is noticed in one of the analysed items. It has been found that more dangerous corrosion growth pattern appears when asymmetric loss of the profile wall thickness arises. That may change the form of buckling from flexural one into warping.