Experimental study on seismic performance of self-centering steel column base with buckling-restrained bar

Abstract:

A self-centering steel column base with buckling-restrained bar was proposed, and its stress mechanism was analyzed. The self-centering parameter (β_sc) and axial force of column were used as design parameters, and four specimens were designed and manufactured. Low cyclic loading test was conducted to compare and analyze the load transfer mechanism, self-centering capability, deformation capability, and energy dissipation capability of the specimens. Test results show that the plastic deformation of the specimens was concentrated on the buckling-restrained bars, and the seismic performance of the structure could be quickly restored by replacing the damaged buckling-restrained bars, indicating that the design intention was realized. The load-displacement hysteretic curves of the specimens were “double flag-shaped”, and the residual story drift was only 0.001 rad after unloading, which means the structure had good self-centering capability. Analysis on the displacement ductility coefficient and equivalent viscous damping coefficient showed that the structure had good deformation capability and energy dissipation capability. With the increase of β_sc, the self-centering capability of the column base increased, and the bearing capability and energy dissipation capability decreased, while the deformation capability was less affected. With the increase of the axial force of the column, the self-centering capability and bearing capability increased, and the deformation capability decreased, while the energy dissipation capability was less affected.