Investigation of the effective factors for eliminating the defect in the CFT columns with an asymmetric L-shaped columns by the finite element Analysis

The use of CFT-filled steel columns is increasing worldwide due to the proper co-operation of concrete and steel, with more concrete steel columns being implemented in circular shapes, which is due to the fact that the core concrete is more enclosed with the circular cross-sections, but sometimes it is impossible to use symmetrical cross sections and other forms such as L-shaped crosses are used, which create less confinement for the core because of their asymmetry. This issue decreases the bearing capacity on these columns formed by an asymmetric L-section. The aim of this study was to study the asymmetric L-shaped cross-section of steel-filled concrete columns in order to provide the reduction of confinement due to effective parameters such as height, steel cross-section thickness and compressive stress. In this investigation, steel wall thickness, height, and compressive strength of concrete on the effect of securing core concrete confinement in L-shaped sections under finite element analysis were observed that the effect of steel wall thickness (t) in L-shaped cross-sections is one of the most effective parameters to remove the confinement defect that the impact of this effect is, on average, about 18.31% more higher than the  parameters of height and compressive strength of concrete. Finally, it was concluded that the asymmetric L-shaped sections would be more confined by changing the thickness of the steel wall compared to the concrete compressive strength and height parameter.