Numerical analysis, resistance, and behaviour of concrete-filled double-skin corrugated steel tubular short columns

Currently, research and engineering communities have a substantial increase in interest in the design and behaviour of novel arrangements for double-skin composite columns. This includes the concrete-filled double-skin corrugated steel tubular (CFDSCST) columns. Accordingly, this paper investigates the resistance and behaviour of CFDSCST short columns under axial compression. Finite element (FE) models for CFDSCST short columns were generated and validated using available experimental tests. Then, a parametric study was generated to suggest a new lateral confining pressure for the sandwiched concrete. This is followed by exploring these columns' axial resistance and behaviour, considering different influencing factors, such as the depth-to-thickness ratio, concrete cylindrical compressive strength, hollow ratio and steel strength. Two main column configurations were considered: outer corrugated steel tubes (OCs) and inner corrugated steel tubes (ICs). The FE-predicted resistances were then compared with the codified resistances of the British, European, and Chinese. Generally, these methods produced conservative predictions for both OC and IC columns. Hence, based on the so-called confinement-based design, a new resistance was provided for the CFDSCST short columns based on the proposed power-law formulae for the lateral confining pressure caused by the tubes with corrugations. It was found that IC columns provide more confinement and a lower ductility index compared to OC columns. Concerning the behaviour, it was found that increasing tube thickness and concrete strength leads to increased column resistance, while increasing the concrete strength produces a column of reduced ductility. Additionally, increasing the hollow ratio, which reduces the sandwich concrete cross-sectional area, leads to a decreased column resistance, while increasing the steel strength, while maintaining the sandwich concrete cross-sectional area, increases the column resistance.