Experimental and numerical investigations into the compressive behaviour of circular concrete-filled double-skin steel tubular columns with bolted shear studs

Abstract

Eight medium-length circular concrete-filled double-skin steel tubular (CFDST) columns were examined under axial compression to evaluate the influence of bolted shear studs on the axial performance of CFDST columns. The specimens comprised six columns with bolted shear studs with longitudinal spacings of 100 mm, 75 mm, and 50 mm, and two control columns without bolted shear studs for comparison. The investigated parameters were the failure mechanisms, load-displacement curves, initial axial stiffness, compressive strength, toughness, ductility, residual strength, as well as load-strain responses. Besides, a finite element (FE) model was developed and validated against experimental results to further investigate the performance of columns. The test results demonstrated that the bolted shear studs avoided shear failure and significantly increased the ductility of the specimens. Reducing the bolted shear stud spacing reduced the intensity of local buckling in the outer tube and improved the confinement effect. Additionally, the confinement effect provided by the outer tube was remarkably improved by introducing the bolted shear studs.