Seismic effectiveness of top-story mass dampers for inelastic two-way asymmetric-plan buildings

Self-mass dampers, which use intrinsic parts of structures as tuned mass dampers, are economically advantageous in terms of the materials and space required. Previous research proposed using the top story of a two-way asymmetric-plan building as a self-mass damper, referred to as a top-story mass damper (TSMD), for suppressing the seismic response of an elastic building. In light of the promising results of that research, this study further explores the seismic effectiveness of TSMDs when two-way asymmetric-plan buildings become inelastic under earthquake loads. Furthermore, this study explores the possibility of using a pair of elastic TSMDs to alleviate the detuning effects caused by yielding of the main structure. One TSMD of the pair is designed according to the previous research and is responsible for suppressing the vibrations of the target building in elastic states. The other TSMD is designed based on the properties of collective force-deformation relationships and is responsible for suppressing the vibrations of the target building in inelastic states. The collective force-deformation relationships are the pushover curves of the target building when subject to the collective modal inertia force vectors of the first triplet of vibration modes of the building. This study looks at one single-story building and one 20-story building, which are shaken into various damage states, as the numerical examples for evaluating the seismic effectiveness of TSMDs for inelastic two-way asymmetric-plane buildings.