一軸偏心した1層木質構造物の終局耐震性能評価耐力偏心がもたらす捩れ振動の終局変位モードの予測と評価指標の提案

摘要

Displacement mode including torsion in ultimate state is clearly related to strength balance of each frame while elastic torsional vibration is characterized by stiffness balance. Therefore, this paper presents displacement mode prediction method especially focusing on timber structure having large strength eccentricity. The method also considers variability of response due to earthquake characteristics. Finally, seismic performance index of torsionally coupled structure which indicates necessary additional strength is formulated by calculating potential energy of each shear wall until ultimate state. The accuracy of the evaluation method is demonstrated via numerous time history analyses and shaking table test.%構造物における耐震要素の配置のバランスが悪いと地震時に捩れが生じ、一部の剛性ゃ耐力が低い構面の局所的な損傷によって層の終局状態が決定され、耐震的に不利になる。そのため、現行耐震基準では偏心率が0.15以上のパランスの悪い構造物に対し、そのペナルティとして形状係数の中の偏心率による割増係数F_eにより、必要保有水平耐力の割り増しが要求される。