Axial compressive behavior of grout-filled double-skin tubular (GFDST) columns with stainless-steel outer tubes: Experimental investigation

In this paper, the axial compression performance of GFDST columns with stainless-steel outer tubes was investigated. A total of 24 column specimens were fabricated and tested. The test specimens' parameters include the thickness of the stainless-steel tube, the width of the carbon steel tube, and the grouting, if any, between the stainless-steel tube and the carbon steel tube. Failure mode, load-displacement curve, and ultimate strength were investigated. Results show that the local buckling of the stainless-steel tube occurs, while the carbon steel tube shows no obvious deformation when there is no grout interlayer. The local buckling of the carbon steel tube occurs when there is a grout interlayer. Before reaching the peak load, the N-Δ curves first shows linearity, then a transition to plasticity. The ultimate strength increases by 31.56%–78.02% with increase in the thickness of stainless-steel tube. When there is no grout between the stainless-steel tube and the carbon steel tube, increasing the width of the carbon steel tube can increase the ultimate strength by 97.03%. The ultimate strength of the specimens filled with grout can be improved by 66.73%.