Performance evaluation of base-isolated structures with sliding hydromagnetic bearings

Abstract

Being an efficient technique for mitigating the seismic response of structures, base isolation is widely used in earthquake engineering practice. The sliding hydromagnetic bearing is viewed as a promising isolation system for seismic protection, owing to its adaptive damping energy dissipation, mild deformation constraint, and easy assembly and maintenance. To verify the applicability and efficiency of sliding hydromagnetic bearings, a performance evaluation of base-isolated structures with a sliding hydromagnetic base-isolation system is carried out in this paper. Numerical simulations are performed to explore the dynamic behaviors of sliding hydromagnetic bearings fabricated recently, for which two models, the power function and polynomial models, are proposed. Parameter identification and model validation are carried out using the data from numerical simulations and quasi-static tests. Backward differential formulas are employed to solve the stiff differential equation invoked by the Coulomb friction associated with the models, which bypasses the computational challenges inherent in conventional integral schemes. For a real-time definition of the instantaneous frequency in the models, the Hilbert–Huang transform is utilized. Comparative studies reveal that the sliding hydromagnetic bearing has an advantage over the lead rubber bearing and the curved surface slider in the control of structural displacement, structural velocity, and structural acceleration. Furthermore, the residual displacement yielded in the sliding hydromagnetic base-isolation system merely shifts the starting position of the bearing on the next movement, and the sliding surface and deformation constraints remain approximately as the initial condition.