Effect of using steel corner tubes on the static compressive and cyclic behaviour of concrete-filled double-skin fabricated columns

The high strength of Concrete Filled Tubular (CFT) sections and Concrete-Filled Double-Skin Tubular (CFDST) sections distinguishes these sections from other conventional structural sections. In this study, an innovative fabrication strategy is implemented to enhance the performance of CFDSTs. Based on this strategy, four ultra-high strength steel tubes are welded to the corners of CFDST columns. Several specimens strengthened with this strategy are subjected to axial compressive and lateral cyclic loading. The static compressive experiments are performed on the short column specimens with one meter length while uniaxial and biaxial cyclic experiments are conducted on the selected three meter long specimens. Thus, through this experimental study, the efficiency of employing corner steel tubes in the improvement of the structural performance of CFDST sections is examined. It is proved that the employed fabrication strategy improves the resistance and the stability of the CFDSTs under the applied loading scenarios.