超高層建物の下層階に部分配置する履歴型ダンパーの効果と影響に関する検討: 長周期地震動を想定した耐震改修

摘要

大都市を中心に存在する超高層建物群は社会の中枢機能を担ってrnいる。超高層建物は，設計用地震動に対する時刻歴応答解析に基づrnき，最大層間変形角0.01rad以下等の制限値を満たすように剛性やrn強度が決められてきた。しかし，海溝型の巨大地震により生じる長rn周期地震動は，超高層建物に設計用地震動と異なる揺れを与え，rn従来の制限値を超える変形を多数回繰り返し生じさせる可能性があrnる。%In long-period ground motions, high-rise buildings are subjected to large cumulative deformations as well as large story drifts. Retrofitting with dampers may be one of the most effective solutions to reduce such seismic responses, This study examines the influences of steel dampers partially installed into the lower part of high-rise buildings. A series of dynamic response analyses are conducted for typical steel high-rise buildings. A long-period ground motion is adopted whose energy spectrum has a peak amplitude at three seconds, and twenty-one story buildings and thirty-five story buildings are substituted by frame models. The results show that the total energy absorption of the dampers installed into forty-percent stories can be equivalent to that of the dampers installed into the whole stories. Oh the other hand, the maximum drift of the story located right on the lower part having dampers would become 1.4 times larger than those of the lower part.