Behaviour of concrete-filled spiral-welded mild-steel and stainless-steel tubes under eccentric axial loading and under pure bending

For concrete-filled steel tubes, cost-benefits result if spiral welding, rather than longitudinal welding, is used for tube fabrication. However, spiral-welded tubes contain unique residual stress and surface imperfection distributions. To consider their structural implications, experimental testing is warranted. Accordingly, the behaviour of concrete-filled spiral-welded mild- and stainless-steel tubes under eccentric axial loading and pure bending was experimentally investigated. For such loadings, existing codified guidelines were found to be directly applicable, while the failure mode was seemingly independent of the steel and fabrication type. Furthermore, load capacities predicted by numerical modelling methods were either conservative or close to the experimental values.