Numerical modeling of rectangular concrete-filled double-skin steel tubular columns with outer stainless-steel skin

Abstract

Concrete-filled double-skin steel tubular (CFDST) columns composed of outer stainless-steel skin have grown increasingly popular in structural applications on account of their attractive appearance, ductility, resistance to corrosion, fire resistance and easy maintenance. However, only one numerical study of the behavior of rectangular CFDST short columns with outer stainless steel tube has been reported. This paper presents the numerical analysis and design of axially loaded rectangular CFDST short columns where the outer tube is made of stainless-steel. A finite element model is created for analyzing the responses of rectangular CFDST short columns. The numerical analysis accounts for the confinement mechanism of concrete, strain hardening of stainless steel and imperfection of steel tubes. A comparative study of numerically predicted and experimentally observed behavior is presented to gain an appreciation for the accuracy of the developed numerical model. A parametric study is undertaken, investigating the performance of a series of rectangular CFDST columns by varying the concrete strength, load distribution, cross-section shape and tube thickness. The ultimate axial strengths predicted using Australia/New Zealand Standard for composite structures are compared against experimental results. It is demonstrated that the numerical model predicts well the responses of CFDST columns where the outer skin is made of stainless steel. Australia/New Zealand Standard yields the accurate predictions of the ultimate axial strengths of rectangular CFDST columns with outer stainless-steel tube.