Experimental investigation of built-up cold-formed steel stub column with and without concrete-filled

Cold-formed steel (CFS) is a steel-based material formed from sheet steel over the rolling and pressing process. CFS is used broadly in the storage rack, wall panel and roof truss system, and discussed here to expand its usage as an important main structural element such as column and beam. Nowadays, CFS applications becoming popular in construction activities, but some of the buckling failures experienced due to poor cross-section and thin surface. These buckling failures; for example, local, distortional, global and lateral buckling should be solved. The production of a built-up section and a combination of materials is one of the modes to solve buckling failure. The objective of this study is to establish a built-up with a channel section which easily available in the construction market and determine their mechanical properties by using experiments. Four experimental activities conducted in the study by analysing the material properties of the channel section and concrete, mechanical properties of the connection test and mechanical properties of the stub column. The ultimate load result of the built-up CFS stub column with two channels section with different arrangements and fastener still obtained the ultimate load value in the same range. However, the ultimate load is increased by 49% when the built-up section is filled with concrete and increased approximately by 50% when the built-up section added another four channels section. In conclusion, the ultimate load of the CFS stub column is increased with increasing the number of channels section, weight and area.