Thin-walled double-skin concrete-filled steel-box stub columns with perfobond connections: axial compressive behaviour

Abstract

Thin-walled double-skin concrete-filled steel tube (CFDST) stub columns with perfobond (PBL) ribs stiffened have broad application prospects in prefabricated modular buildings, bridge pylons and tunnels. To evaluate its application potential in engineering, this paper designed nine thin-walled CFDST box stub columns stiffened with PBL ribs and conducted axial loading tests. The failure modes, load-displacement curves, local buckling response, ultimate bearing capacity and ductility of the specimens are discussed. Test results show that PBL ribs constrain the local buckling of columns. Through analysis, the influence of the slenderness ratio, the hole distance and the hole diameter of the PBL rib on the axial compression behavior of the specimen was clarified. In addition, a finite element model was established and the accuracy of the model was verified through experimental results. Subsequently, extensive parametric studies were conducted to obtain the effects of section hollow ratio, steel ratio of the section, steel strength, and concrete strength on the bearing capacity and ductility of PBL ribs stiffened CFDST box stub columns. Finally, a prediction formula for the bearing capacity of PBL ribs stiffened CFDST box stub columns considering local buckling was proposed.