Experimental, numerical and theoretical research on compressive-bending behaviour of tapered high strength CFDST columns with large hollow ratios for support structures of wind turbines

This study investigates the compressive-bending bearing capacity of tapered large hollow ratio concrete-filled double-skin steel tubular (TLH-CFDST) structures, which are widely used in critical applications such as large-capacity wind power equipment, high-rise buildings, and offshore platforms. Experimental tests and finite element (FEM) analysis were conducted on six high-strength steel TLH-CFDST columns to analyze failure modes and bearing capacity influences. A full-process prediction model was developed based on the section-space stress integration (SSI) theory and validated through FEM results and parametric analysis . A calculation method incorporating edge yield and full plasticity theories was proposed for the compressive-bending bearing capacity by introducing the section yield coefficient. The results show that the SSI model's moment-displacement curves align well with experimental and FEM data, and the proposed method provides more accurate and stable N-M curve predictions compared to existing specifications. This study offers a reliable theoretical and practical framework for TLH-CFDST structure design. • Six high-strength steel TLH-CFDST specimens with large hollow ratios were tested to study compression-bending behavior. • The FE model incorporating material damage effect of sandwich concrete was established and verified. • Influence of geometric parameters, material strengths was discussed in parametric study. • A full-process model based on SSI theory was developed and validated via FEM and parametric analysis. • Compressive-bending capacity method integrating edge yield and full plasticity theories via section yield coefficient.