Hao Liang¹, Yanling Guo^2,

To study the axial compression performance of high-strength recycled concrete columns with built-in square steel tubes, ABAQUS software was used to model and analyze two existing test specimens, verifying the accuracy of the model. On the basis of a reliable model, parameter analysis was conducted on 13 specimens, with variable parameters including square steel tube thickness, square steel tube strength, and slenderness ratio. The results showed that the established finite element model exhibited longitudinal reinforcement buckling and steel tube tearing deformation consistent with the experimental results, and the height of the load axial displacement curve was consistent. The average error of the ultimate bearing capacity was within 5%; The increase in steel tube thickness has little effect on the axial compression bearing capacity and stiffness, while the increase in steel tube yield strength has a significant impact on the axial compression bearing capacity and residual bearing capacity; With the increase of slenderness ratio, the axial compression stiffness and ultimate bearing capacity of composite columns are obviously degraded. A numerical calculation method between the axial compression stability coefficient and slenderness ratio is fitted, which can be used as a reference for the design of composite columns.

Built-in square steel tube, High strength recycled concrete, Stacked column, Axial compression performance, finite element analysis