Prediction of Lateral Confinement Stress for Concrete Filled Steel Tube Column

Structural columns that are made up of two or more different materials are known as composite columns. Studying composite structures is beneficial since it is a new and modern way to build structures and benefit from materials in a different way. Concrete- filled steel tubular structures makes the composite column a very stiff, more ductile, cost effective (as compared to reinforced concrete structures) and consequently a structurally efficient member in building and bridge constructions. In this study a numerical simulation of a circular composite column was conducted. In order to achieve the study objectives, Finite Element Method (FEM) based software (ABAQUS) was used due to many advantages including saving time of the calculation and providing a simulation of the behavior of the member. A load-deflection curve of a circular composite column was plotted by considering the stress-strain curve of normal concrete and compared with the experimental results. It was found that the load capacity was less than that of experimental results. The reason of this underestimation was the confinement effect. A correction factor for lateral confining pressure of 1.5 was found for circular sections since the equation used for confining pressure obtain from literature was applicable to square composite columns.