Input energy of base-isolated structures using complex stiffness dampers

This paper shows comparison of earthquake input energy to two types of base-isolated structures. Earthquake input energy for a base-isolated structure incorporated with a magneto-rheological fluid damper using the acceleration reduction control rule is found to be smaller than that of a structure with a viscous damper having the same equivalent damping coefficient. Complex damping is employed to model the magneto-rheological fluid damper and it is shown that the difference of the phase angles of the complex velocity transfer functions for the viscous and complex damped models causes the difference of the earthquake input energy.