Behaviour of Geometrically Nonlinear Columns: Towards an Accurate Structural Design of Columns Made Using Hot Rolled-Open Steel Section

Geometrically nonlinear columns have been used for a variety of reasons in buildings, and their use has become even more prevalent in our time. Much research has been carried out regarding columns and arches, but geometrically nonlinear columns have not been extensively covered. Thus, this paper sheds a light on the behaviour of nonlinear columns when subjected to loading. For that purpose, two different cases of geometrical nonlinearities were considered. These columns were modelled using a validated Finite Element (FE) model. Each of the columns was loaded up to the buckling load and the displacement was recorded. Length of the column, the included angle (i.e., shallowness or span/reach ratio) and boundary conditions were taken as variables and the behaviour of columns noted each time. Additionally, a brief review of the available guidance from building codes showed a gap when it comes to nonlinear steel columns design. The results of this study showed a similarity between these columns and arches in terms of their behaviour up to the point of buckling. A parametric study was also performed to highlight the sensitivity of this hypothesis to changes in the studied parameters