This study proposes a seismic response control device which prevents mid- and low-rise buildings from collapsing at specific story under severe earthquake ground motions. The device consists of the frame and the passive damper, which are mounted outside of the building. First, we constructed an analytical model of the device using a mass-spring-damper system and then performed time history seismic response analysis of the four-story steel buildings. We confirmed that the proposed device equalizes deflection of all the stories and reduces the maximum story deflection without excessive increase of the maximum response acceleration.
