地震・津波作用下における津波避難ビルの動的解析
Abstract
2011年の東北地方太平洋沖地震では,多くの鋼構造建物が損壊し,柱脚部の破壊や1階の層崩壊,杭の破壊や引き抜きによる転倒などの被害が見られた.地震動を受けた鋼構造建物に津波が押し寄せ,建物に作用する荷重が増加したことで被害が拡大したものと考えられている.この震災を受け,構造上安全性の高い津波避難ビルの必要性が高まり,高台が近くに存在しない海岸地域では,多くの自治体で避難ビルの設置を検討している.また,各関係機関は,津波避難ビル等の構造上の要件に係わる暫定指針を提案した.この指針では,浮力や津波荷重の設計式の提案,建物の倒壊や転倒などの複合的な被害に対して検討されており,指針に基づいて津波避難ビルの具体的な設計例も示された.
Since the 2011 Great East Japan Earthquake, the need for tsunami refuge buildings which contribute to protect human lives during tsunami disasters has been increased. The main objective of this study is to carry out safety evaluation of a tsunami refuge building by dynamic analysis using the Adaptively Shifted Integration (ASI)-Gauss code. This code is a finite element code that provides higher computational efficiency than the conventional code and can cope with strong non-linear and discontinuous behaviors such as member fracture and elemental contact. In this study, the following two load conditions were considered; a seismic excitation, a fluid force which contains buoyant force and tsunami force. By performing the analysis with the loads consecutively applied to the tsunami refuge building, it was confirmed that a tsunami load had a great effect on the damage of the building.