Eccentric Compression Behavior of RCFST Columns with Web Perforated T-Shaped Stiffeners

Based on the previous axial compression tests by the authors, this study investigates the eccentric compression behavior of rectangular concrete-filled steel tubular (RCFST) columns with web-perforated T-shaped stiffeners through finite element analysis. Finite element models (FEM) of RCFST columns were established and validated against failure modes and load-displacement curves obtained from axial compression tests. Subsequently, a detailed parametric analysis of RCFST columns under eccentric compression was conducted, including the stiffening details (i.e., material strength, the number, and dimension of stiffeners). Results show that the stiffening method enhances the RCFST ultimate bearing capacity. Increasing the number and dimensions of stiffeners, as well as the strengths of steel and concrete, leads to higher peak loads, whereas an increase in the slenderness ratio results in a reduction in ultimate capacity. Finally, an N-M (axial force-moment) interaction curve calculation method for RCFST columns with web-perforated T-shaped stiffeners was proposed, simplifying the calculation process for stiffeners and incorporating the correction factors for eccentric columns. The results indicate that this method can achieve higher accuracy while ensuring safety, whereas the calculations based on CECS 28 are overly conservative.