Axial behavior of double skin corrugated steel tube columns filled with normal strength concrete

In this research an experimental study is carried out on four concrete filled double skin steel tubular (CFDST) and concrete filled double skin corrugated steel tube CFDSCST slender columns. This research is considered as a second part of a previous one done by the authors on CFDST stub columns. A verified finite element (FE) program (ABAQUS) is used to give better understanding of the behavior of CFDSCST under axial load. A parametric analysis was then produced in order to show the axial behavior of these columns while taking into account several affecting elements, including the steel strength, hollow ratio, concrete compressive strength, length, and depth-to-thickness ratio. It was found that using the corrugated steel in the inner tube offer more confinement and a lower ductility compared to using corrugated steel in outer tube. It was found that increasing concrete strength cause reduction in a column ductility, increasing tube thickness and concrete strength increases column resistance. Increasing hollow ratio result in decreasing columns strength as a result of decreasing the sandwiched concrete. Euro code and AISC is evaluated against FE model results.