T 型钢-圆钢管混凝土组合异形短柱轴压性能试验研究

To facilitate assembly connections between concrete-filled steel tubes (CFST) and beams or walls, this study proposed welding multiple T-shaped steels to the exterior of a circular steel tube, forming a new type of composite special-shaped column called T-steel concrete-filled steel tube (TCFST) column. This research designed and tested four TCFST columns with different cross-sectional shapes (I-shaped, L-shaped, T-shaped, and cross-shaped) and one standard CFST column under axial compression. The experimental phenomena and failure modes of the specimens were analyzed and compared, focusing on how the T-steels influence the failure patterns and stress-strain relationships of the CFST components. The results show that I-shaped and L-shaped TCFST columns exhibit shear failure consistent with that of the standard CFST column. In contrast, the circular steel tubes in T-shaped and cross-shaped TCFST columns transition to steel tube buckling due to the constraint provided by the T-shaped steel segments. For TCFST columns with single-axis symmetric cross-sections, the stiffness center shifts gradually toward the T-shaped steel side as the axial load increases, inducing additional bending moments. Based on the experimental findings, a superposition method was developed to calculate the axial compressive capacity of TCFST columns. The computed results align well with the experimental data.