Design of an active mass damper to simultaneously mitigate seismic acceleration in superstructures and substructures of a mid-story isolation building

This paper proposes a design method for the active mass damper (AMD) applied to super high-rise buildings designed as a building mass damper (BMD)The BMD is a seismic response control devicewitha soft layer at a relatively high position in the building,and makes the part above the soft layer work as a tuned mass damper. It is designed to decrease the seismic response of the part below the soft layer by amotion of the superstructure. However, since the displacement of the soft layer is limited, any displacement exceeding the allowable clearance must be suppressed. The displacement of the soft layer can be reduced withadditional damping and/or springs. However, the addition ofdamping and/or springshasthe countereffect of increasing the seismic response of the building. To solve this problem, we proposed the design method for the AMD,which aims to make the BMD with additional damper and/or springsact like a BMD with no additional element. The effectivenessof the proposed method was demonstrated through numerical calculations.