Axial compressive behavior of tapered CFDST column with large hollow ratio

Abstract

This study investigates the axial compression performance of tapered large hollow ratio concrete-filled double-skin steel tubular column (TLH-CFDST) with high strength steel through test and finite element analysis. Seven specimens were subjected to axial compression tests to reveal the failure modes that occurred at the top section of the columns. Based on the test results, a validated finite element model (FEM) and parametric analysis were developed to analyze the influence of key parameters on compressive performance. A full-process prediction theory for axial compression, based on continuum mechanics equations with a recommended intermediate principal stress coefficient of b = 0.3 under the unified strength theory (UST), was proposed. It demonstrated high accuracy compared with Tresca and Von-Mises criteria, with mean values (MV) of 0.996 for capacity and 0.963 for stiffness, and coefficients of variation (CV) of 0.023 and 0.056, respectively. Based on the elasto-plastic solution of a thick-walled cylinder under plane strain conditions, a theoretical formula for predicting axial compression capacity was derived with a coefficient of determination (R²) of 0.987 and coefficients of variation (CV) of 0.091. The results provide a reliable theoretical and practical basis for the design and application of high-strength TLH-CFDST structures in engineering practice.