Active variable stiffness system with non-resonant control

The active variable stiffness (AVS) system is proposed as a seismic respons e control system. It actively controls structural stiffness of a building t o establish a non-resonant state against earthquake excitations, thus suppr essing the building's response. It consumes a relatively small amount of en ergy and maintains the safety of the building in moderate to severe earthqu akes. In order to accumulate and analyse practical data, a building was con structed as a trial structure about ten years ago. This paper describes the control algorithm, the applied system, some observed earthquake records, v erification of control effectiveness based on simulation analyses, and some issues concerning system maintenance. Through earthquake observations, it was confirmed that the system could select the appropriate stiffness that a ssures a non-resonant state, which results in a minimum response. Copyright (C) 2001 John Wiley & Sons, Ltd.