Numerical investigation and calculation method of concrete-filled bimetallic tubes subjected to concentric tension

Abstract

Concrete-filled stainless steel (outer)-carbon steel (inner) bimetallic tubes (CFBT) are potential to be applied as structural members in the corrosion-prone environments. A detailed numerical investigation on the mechanical performance and calculation method of CFBT members under concentric tension is carried out in this paper. A finite element analysis (FEA) model adopting three-dimensional elements is established, and related experimental results of conventional concrete-filled carbon steel tubes (CFST) and concrete-filled stainless steel tubes (CFSST) are used to validate the FEA model. Then, the calibrated FEA model is used to investigate the performance of CFBT tensile members, especially the composite actions and stress distribution laws between the two tube-layers and the infilled concrete, which play the key role in the load-carrying capacity of the composite member. To quantitatively determine the influence of different parameters on the load-carrying capacity of CFBT tensile members, a wide-range parametric analysis is performed. Finally, a calculation model is proposed to be used to predict the ultimate tensile strength of CFBT members subjected to concentric tension, and the model-predicted values show good agreement with the FEA-computed results.