Stiffened T-Shape Concrete Filled Tubular Tall Columns Axial-Bending Interaction

Abstract

The recent emergence of concrete-filled steel tube (CFST) columns represents a significant advancement in composite column technology. This innovative approach synergistically combines concrete and steel, where the steel tube acts as a confining medium that enhances the concrete's strength and ductility, while the concrete in turn mitigates the risk of both internal and local buckling in the steel tube. The primary benefits of CFST columns over traditional concrete columns include the elimination of the need for reinforcement and formwork, faster construction times, cost savings, reduced column dimensions, and improvements in load capacity, ductility, and energy absorption capabilities. This research investigates the impact of T-type steel stiffeners on the behavior of square CFST columns through numerical modeling. Utilizing the ABAQUS software, the study analyzed ten specimens to understand this effect comprehensively. A total of fifty CFST specimens reinforced with T stiffeners were modeled to assess varying parameters, such as wall thickness, stiffener depth, and steel grade, under axial loads and bending moments. For each specimen, a P-M (axial force-bending moment) diagram was generated. The outcomes of this analysis culminate in the proposal of an axial force-bending moment interaction diagram specifically for CFST columns reinforced with T stiffeners, providing valuable insights for the design and application of these columns in structural engineering.