This paper discusses a semiactive control strategy with MR dampers integrated for base-isolated buildings. In this proposed strategy, MR dampers are utilized as variable slip-force level dampers. By controlling only the magnitude of its slip-force, the damper can exhibit hysteresis in any seismic event, then working as an efficient variable friction damper and achieving a high level of energy dissipation. The proposed scheme controls the magnitude of the slip-force level of the MR damper based upon the measurement of absolute acceleration responses, taking into account a simply approximated yet useful relationship between the supply electric voltage and the set slip-force level. The proposed algorithm could be applied to a variety of isolation systems. Indeed, the employed algorithm can be applied to linear and friction isolation systems without changing any parameters involved in the algorithm. The performance resulting from the proposed control scheme is compared with those provided by employing the clipped optimal and skyhook damper-based semiactive control schemes, respectively, for the linear isolation and friction isolation systems. The results obtained from the proposed scheme demonstrate that this control algorithm can reduce the base displacement without increasing the base shear or the structural shear forces.
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