Author(s)

Julio C. Miranda

Abstract

This paper presents the mathematical model of an energy-formulated approach for the passive control of buildings isolated at several levels. Viscous energy dissipating devices are also inserted in parallel with the isolators. These levels may occur naturally, such as at the base of setbacks, the base proper, or may be selected so as to obtain a desired seismic performance. With that aim, using modal analysis the present paper formulates the response of buildings idealized as two degree of freedom systems, in terms of the kinetic energy imparted upon each mass. The resulting equations provide the corresponding modal properties such as mode shapes, frequencies, damping, and participation factors, m a manner easy to understand and rationalize. These results are applicable to the passive control of the seismic response, in the measure that the isolation and damping devices are manufactured to correspond to the selected values. It is hoped that this paper presents an innovative way of thinking in the manner in which engineers can control the behavior of their designs. It extends the range of applications thus far envisaged for state-of-the-art protecting devices such as isolators and dampers.

Keywords