Performance evaluation and codal assessment of double-skinned solid-core CFST columns with varying steel configurations

This experimental study explores the behaviour of columns with double-skinned solid core concrete-filled steel tubular (DS-CFST) sections. Many experimental studies have been conducted on double-skinned hollow CFST sections so far, and this research has involved evaluating the performance of various configurations of steel tube geometry (square and circular combinations) of solid-core CFST specimens. Eight CFST short columns were subjected to axial compression, each measuring 410 mm in height (H). The study investigated the effects of various parameters, including concrete strength, steel area, width-to-thickness ratio, steel and concrete core percentage, and inner steel embedment position, on CFST short columns with slenderness ratios (λ) ranging from 9.4 to 10.9. The test results showed improvements in DS-CFST column axial compression, ductility, stiffness, failure modes, and structural behaviour due to adequate steel inner tube embedment. The CFSC specimens exhibited 6.64 times higher results than the steel tubes and 2.33 times greater strength than the CFST specimens, while other steel tube embedded specimens demonstrated significant strength improvements. The results are checked with the current codal provisions, ANSI/AISC-360, EC-4 and modelled by an artificial neural network (ANN).