Numerical Analysis on Seismic Behavior of Steel Tubular Column-Shear Wall Transformation Nodes

This study investigates the seismic performance of steel columns with different heights of concrete core fill under the combined action of axial compression and low-cycle reversed loading. The comparison between finite element modeling and experimental results is employed to validate the seismic performanceaccuracy of finite element modeling method. The fundamental parameters studied in the finite element model include the height of the core concrete, core concrete strength, steel material strength of the outer steel tube, axial load ratio, and the diameter-to-thickness ratio of the members, among others, all of which have a significant impact on the seismic performance of steel columns. The finite element analysis primarily focuses on hysteresis loops, skeleton curves, initial stiffness, stiffness degradation curves, and energy dissipation capacity. The following findings were obtained: Firstly, the height of the core concrete significantly influences the seismic performance of steel columns. Steel columns with lower concrete fill heights exhibit lower peak loads and failure displacements due to the smaller volume of concrete fill. As the concrete height increases from 0.25 times the column height to 0.5 times the column height, both peak loads and failure displacements increase significantly, along with a notable increase in the total number of cyclic loading cycles. This underscores the importance of considering concrete filling height in the design of steel columns to ensure adequate seismic performance. Secondly, the influence of the strength of the core concrete and steel material on seismic performance is relatively minor. High-strength concrete and steel do not significantly increase the initial stiffness of steel columns. This suggests that within a certain range, different concrete and steel materials can be chosen without a substantial impact on seismic performance. However, practical engineering still requires the selection of appropriate materials based on specific strength and stiffness requirements. Finally, an increase in the axial load ratio and the diameter-to-thickness ratio of members can enhance seismic performance to some extent, particularly in terms of energy dissipation capacity. Increasing the axial load ratio improves the load-carrying capacity of steel columns, while increasing the diameter-to-thickness ratio enhances their stiffness, thereby improving their seismic performance. Therefore, practical design considerations should comprehensively account for take these two parameters into account to optimize the seismic performance of steel columns. In summary, this study, through a detailed parameter analysis, elucidates the significant impact of core concrete height on the seismic performance of steel columns and provides a robust basis for the design and optimization of steel column structures.