Abstract:
Concrete-filled steel tubular (CFST) columns are widely used in high-rise and super high-rise buildings, bridges, industrial plants, and other engineering structures. However, existing research is mostly limited to single-column models, failing to truly reflect the impact of beam-column connections on the mechanical behavior of columns in practical engineering. To more accurately reflect the mechanical behavior of CFST columns in structural systems, this paper, based on the data from a quasi-static test of a double-column CFST specimen, employs the finite element method to establish a numerical model of double columns. It investigates the influence of beam-column construction on the restoring force characteristics of CFST columns and compares it with the traditional single-column model. The study finds that an increase in axial compression ratio can enhance the peak load capacity of the skeleton curve but significantly reduce the ductility of the component. Compared to the single-column model, the double-column model exhibits a slower decline in bearing capacity after yielding, with a gentler descending segment in the skeleton curve, demonstrating superior ductility and slower stiffness degradation. The results indicate that the restraining effect of beams has a significant impact on the hysteretic behavior and deformation capacity of CFST columns. The double-column model can more accurately reflect their actual mechanical deformation characteristics. The research findings can provide references for numerical modeling and theoretical analysis in the seismic design and performance evaluation of CFST columns, carrying significant theoretical and practical value.