Compressive behavior of concrete-filled double skin steel tubular short columns with the elliptical hollow section

Recently, many researchers have shown a great interest in single skin concrete-filled steel tubular (CFST) columns with circular and rectangular sections, as well as elliptical sections that contain the performance of both sections. On the other hand, elliptical concrete-filled double skin steel tubular (CFDST) columns are a new member of the CFDST family and developed form of elliptical CFST columns. In the literature, there are a limited number of studies focusing on this new structural element. So, doing both experimental and analytical investigations on the elliptical CFDST column is required to provide an opportunity for its covering in the design codes. Herein, a finite element (FE) method was used to constitute a model for investigating the axial compressive performance of elliptical CFDST short columns. The software ABAQUS was employed to describe the nonlinear behavior of materials and the complex interplay between the steel and concrete components. The developed model was also verified by comparing with the experimental results. Additionally, two widely used design codes (AISC and Eurocode 4) were applied. After verification of the developed FE model, the ultimate axial strength, axial load-displacement curve, failure mode, and stress analysis of elliptical CFDST short columns were studied comparatively. The results indicate that the generated FE model could be employed in the estimation of the behavior of elliptical CFDST short columns. Besides, the parametric study revealed that the thickness of the outer steel tube, steel yield strength, concrete compressive strength, and aspect ratio of the elliptical section exert an influence on the performance of the elliptical CFDST short columns.

Automated summary

Researchers have shown great interest in elliptical concrete-filled double skin steel tubular (CFDST) columns and conducted experimental and analytical investigations to provide an opportunity for its inclusion in design codes. A finite element method was used to study the axial compressive performance of CFDST columns, revealing factors influencing their behavior, with the developed model verified against experimental results.