Mohammed Jalil Jihad Karakosh - Assistant Lecturer, Department of Building & Construction Technical Engineering, Al-NajafEngineering Technical College, University of Al-Furat Al-Awsat Technical ,Najaf, Iraq
Reza Moradi - PhD in structure Engineering, Department of Civil Engineering, Faculty of Engineering, RaziUniversity, Kermanshah, Iran

Considering that the CFDST column is a combination of concrete and steel, which has a set of advantages of reinforced concrete columns and steel columns, the composite column is more malleable than concrete columns, and their connections are similar to steel buildings. Adding concrete inside the column not only increases the bearing capacity of the steel section but also improves its lateral stiffness, which is very useful in terms of controlling the relative displacement of the floors. Examining the types of common constructions shows that despite the advantages that are listed for these types of structures, their use is not yet widespread and one of the reasons for this can be the lack of sufficient and extensive research in this regard. Therefore, it seems necessary to carry out more investigations on mixed structures. Therefore, the main goal of this research is to investigate numerically and experimentally the factors affecting the behavior of composite columns.

Steel columns, concrete-filled steel tubes, concrete, steel, composite