Investigation of local and distortional buckle behavior in cold-formed steel columns with circular body cavity under axial load

Nowadays, light steel structures are gaining popularity due to their flexibility, rapid assembly possibilities, and various usage advantages. However, there arises a need to leave certain openings in the columns of these structures in line with structural requirements or architectural design demands. These openings can be created to allow the passage of electrical installations and mechanical systems or may be preferred for aesthetic concerns. However, the impact of these openings on the mechanical performance of the columns has not been sufficiently studied. The presence of openings can negatively affect critical mechanical properties such as the load-bearing capacity, buckling mode, and energy absorption capabilities of the columns. The influence of the geometry and size of the openings on the local and overall buckling behavior of the columns has also not been clearly defined. This thesis aims to thoroughly examine the effects of circular openings left in light steel structures on mechanical performance. A comprehensive experimental study was conducted using a total of 16 samples. The samples were divided into two groups: 8 elements exposed to normal temperature and 8 elements exposed to high temperature. In both groups, columns with a height of 500 mm and 300 mm, without openings and with circular openings of different diameters, were included. These openings have diameters of 0 mm (no openings), 48 mm, 96 mm, and 144 mm, respectively. In the experiments, the behavior of each sample under axial load was examined, and the obtained data were analyzed. As a result of these analyses, the effects of different opening diameters and exposure to high temperatures on the load-bearing capacity, buckling resistance, and energy absorption capabilities of the columns were evaluated in detail. The results of this study aim to establish a stronger foundation for the safety and performance of columns used in the design and construction of light steel structures.