Simulation Analysis of Steel Frames Supported by Foundations at Different Ground Levels with the Self-Centering Column Base Joints on the Upper Ground

Due to the strong constraint conditions, the column on the upper ground of frames supported by foundations at different ground levels will have large residual deformation after the earthquake, the self-centering structure is useful to reduce the residual deformation. At present, there is no research on the application of self-centering structure to the structures supported by foundations at different ground levels. Therefore, in this paper, the self-centering structure is applied to the upper grounding to study the seismic performance of the steel structures supported by foundations at different ground levels. The seismic performance of the frame is simulated by finite element software and the results are analyzed. To study the seismic performance of steel frames, the structure of the self-centering column base joints and the form of steel frames are designed. Considering three design parameters, including the size of the slotted hole of the buckling restrained steel (BRS) plate and the connecting plate on foundation, the width of the dissipated section of the BRS plate and whether the connecting plate on foundation is arranged, five frame models are established by using the finite element software ABAQUS to simulate under the lateral cyclic loading. The effects of hysteretic curves, stiffness degradation, energy dissipation capacity, residual deformation and other seismic properties of each specimen were compared and analyzed. Research results show that the steel frame with the self-centering column on the upper ground has good self-center ability. However, the parameters of the steel frame with the self-centering column on the upper ground will affect the self-centering ability and seismic performance. The slotted hole can delay the plastic time of BRS plate, but has little effect on the overall residual deformation. The width of the dissipating position has a great influence on the self-centering effect and energy-dissipating capacity of the whole specimen. With the increase of the width, the dissipating capacity and stiffness of the structure increase, but the self-centering effect decreases. The connecting plate on foundation can provide certain energy dissipation capacity and stiffness under earthquake, but the overall residual deformation will increase.