Numerical Investigation on the Performance of Concrete-Filled Double-Skin Tube Columns Under Blast Loading

In recent years, Concrete-Filled Double-Skin Tube (CFDST) columns have become a promising structural system, demonstrating improved strength, ductility, and sustainability when compared to conventional column designs. CFDST columns comprise two steel tubes placed concentrically infilled with concrete. Square and circular hollow steel sections are commonly used in CFDST. The higher strength-to-weight ratio is a primary factor in preferring CFDST columns over Concrete-Filled Steel Tube (CFST) columns. In this study, a circular CFDST column is modeled and validated using the Finite Element Analysis-based software ABAQUS. The response of the CFDST column under blast loading is explored. The influence of variables such as axial loading, outer steel tube thickness, hollowness ratio, angle of incidence, and scaled distance on blast resistance is determined through the parametric study. The study also explores the effectiveness of the introduction of steel reinforcement in the concrete infill of the CFDST column for enhancement of blast resistance. The results highlight that increasing the outer steel tube thickness and incorporating steel reinforcement lead to an enhanced blast resistance of structures. However, the study does not find definitive evidence indicating that the hollowness ratio affects the behavior of the CFDST column.