Experimental and Numerical Study of the Concrete‐Filled Double‐Skin Columns With Stainless Steel Outer Tubes Subjected to Cyclic Loading

ABSTRACT This paper investigates experimentally and numerically the behavior of the concrete‐filled double‐skin columns with a stainless steel outer tube (CFDSST) subjected to cyclic loading and constant axial load, which the use of these types of columns in tall buildings can be widely useful. In order to achieve this, a total of six specimens were created and tested. The specimens include two cross‐section combinations: circular–circular and circular–square, with varying diameters and lengths of the inner tubes. The purpose of the test is to examine how the geometry and dimension of the inner tube affect the lateral load–displacement ( P‐Δ ) hysteresis and envelope curves, dissipated energy, and stiffness degradation. The test results indicate that the specimens with a circular–circular cross‐section exhibit better behavior compared to the specimens with a circular–square cross‐section under cyclic loading conditions. This behavior is also improved by increasing the diameter of the inner tube. To verify the results, a finite element (FE) model was created, which shows that the lateral load–displacement ( P‐Δ ) hysteresis curves and the deformation shape have good agreement with the experimental results.