Axial behaviour of concrete-filled corrugated steel tubular column embedded with structural steel

摘要

Concrete-filled galvanized corrugated steel tubular (CFCST) columns have been proposed as new composite members to improve the corrosion resistances and reduce the anticorrosion maintenance costs of concrete-filled steel tubular (CFST) structures. In this study, the axial behaviour of CFCST columns embedded with structural steel (CFCST-S) was investigated using comparative experiments and non-linear finite clement analysis accompanied by multiple monitoring and in-depth discussions. The study revealed that, even when they are not configured with transverse reinforcements, the local stability and post-peak behaviour of the CFCST-S are competitive owing to the effectiveness of the confinements provided by the thin-walled corrugated steel tube (CSP). The unique local bending effect in the CSP was verified and discussed to reveal the mechanical nature of CSP-concrete columns. Next, a theoretical model of the non-uniform stress distribution, after fully considering the bidirectional curvature of the CSP, was developed. It is found that the CSP mainly provides hoop confinements for the infilled components instead of bearing the axial load owing to its "circumferential tight effect" and "vertical offset effect". Based on equivalent simplifications and parametric studies, the current formula to calculate the nominal hoop stress in the CSP was modified. Finally, a design method was proposed for the prediction of the axial bearing capacity of the CFCST-S. (C) 2020 Elsevier Ltd. All rights reserved.