Investigating the impact resistance of self-compacting alkali-activated slag concrete-filled steel tubular columns

This research presents a comprehensive investigation into the behaviour of self-compacting alkali-activated slag concrete-filled steel tubular (SACFST) members when subjected to lateral impact loading. By integrating alkaliactivated slag concrete (AASC) with concrete-filled steel tubes (CFST), the study creates a novel composite material that leverages the advantages of both components. AASC, an eco-friendly alternative to conventional concrete, promotes sustainability, while CFST enhances structural performance by delaying local buckling and preventing inward collapse of columns. The study utilizes finite element analysis to evaluate the SACFST specimens, validating the accuracy of the experimental results and subsequently conducting a parametric sensitivity analysis on full-scale CFST specimens. The analysis focuses on critical parameters such as tube diameter (D), thickness (T), impact velocity (Vo), and hammer mass (M). The diameters considered are 300, 400, and 500 mm, with thicknesses of 3, 6, and 9 mm, impact velocities of 10, 15, and 20 m/s, and hammer masses of 1000, 1500, and 2000 kg. Using Taguchi's Design of Experiments, nine specimens were tested based on an L9 orthogonal array. CFST7 exhibited the highest impact force (7829.4 kN), while CFST1 showed the lowest (2474.0 kN). Maximum residual displacement was observed in CFST3 (392.94 mm), whereas CFST9 had the lowest (25.81 mm). The study highlights critical dynamic responses, including plastic deformation and failure modes, offering insights into CFST column behaviour under lateral impact.