エネルギーの釣合に基づく1層NCブレース架構の地震応答予測

摘要

The authors have proposed Z-type and anti-Z-type NC braced frames that reduce elastic acceleration response by elastic energy accumulation due to incremental deformation. Numerical analyses of these NC braced frames as well as an X-type brace were carried out to examine their seismic response behavior. A method for predicting their seismic response values based on the principle of energy balance is formulated and prediction accuracy is verified by numerical results. Maximum acceleration, maximum story-drift deformation and residual story-drift deformation by incremental deformation under elastic vibration, as well as accumulated plastic deformation ratio of the brace, and residual story-drift deformation by incremental deformation under elasto-plastic vibration can be calculated with excellent accuracy by the energy balance method.%地震時の変位，絶対加速度応答低減のため，安価で性能の安定し た鋼材ダンパーが多用されているが，ダンパーが弹性となる地震時 にはエネルギー消費が行えず，構造物が高剛性を維持するので絶対 加速度が高くなりやすい構造部材が弾性に留まる程度の地震動に おいても，絶対加速度等が比較的高い場合には室内什器の転倒や滑 りといった被害が生じる可能性が指摘されており,早期から地震応 答を低減することが重要となる.ダンパーを早期降伏させることで 絶対加速度の上昇を抑制可能だが，比較的発生頻度が高い地震動レ ベルからダンパーを損傷させる必要がある.