Behaviour of concrete-filled corrugated steel tubes under axial compression

Concrete-filled tubular (CFT) structures are exposed to increasingly complex environments with ever-broadening applications. Anticorrosion maintenance is generally difficult and expensive for established structures exposed to the air. Due to the superior corrosion resistance and the high lateral stiffness of the corrugated steel pipe (CSP), concrete-filled corrugated steel tube (CFCST) is proposed which has the similar working mechanism with the tube confined concrete columns. Such innovative composite member has advantages such as free of maintenance, ease of construction, high load-bearing capacity, good ductility and strong interlocking effect between CSP and concrete. In order to verify the load bearing reliability of concrete-filled corrugated steel tube (CFCST), twenty-one short columns including twelve CFCSTs were tested under axial compression. It was found that the CFCST is a tube confined concrete member and behaves slightly better than tubed-concrete columns. The strain and stress of CSP are discussed in detail to clarify the confinement effect. As well, solid nonlinear finite element models (FEM) were established to investigate the influence of key factors including geometries of CSP and strength of materials, which were summarized in the confinement index. Based on early studies on steel tube confined concrete and the parameter analysis in this paper, a suitable design method to predict the ultimate axial compressive load capacity for CFCST columns is proposed in this paper.