Axial compressive behavior of double-skin steel-plate composite walls with parallel CFST columns

This study analyzed the axial compressive behavior of double-skin steel-plate composite walls with parallel CFST columns (P-CFST-DSCWs) to improve structural stability and performance under axial loading conditions. Four specimens underwent axial compression tests, focusing on key design factors such as steel plate thickness, CFST column spacing, and aspect ratio. Experimental and finite element analyses were performed to examine load-bearing mechanisms, record failure modes (including steel bulging, concrete crushing, and overall instability), and confirm model accuracy. Results indicated that increasing steel tube thickness significantly enhanced initial stiffness, peak load capacity, and confinement effects on the concrete core, contributing to improved structural integrity. Reducing CFST column spacing lowered post-peak ductility, suggesting that closer spacing could limit deformation capacity under extreme loads. Specimens with greater aspect ratios demonstrated susceptibility to global buckling, leading to compromised ductility and reduced load capacity. Comparative analysis revealed close alignment between finite element predictions and experimental findings, supporting the reliability of the model in simulating axial compression behavior in P-CFST-DSCWs. A calculation model for axial compressive capacity was introduced, integrating steel confinement effects and steel-concrete synergy; results demonstrated greater accuracy and stability compared to traditional methods. This research provided essential insights for optimizing P-CFST-DSCW design to enhance load-bearing capacity and energy dissipation.