Study on Deterioration Behavior of Wooden Houses Subjected to Repeated Large Earthquakes and Proposal of the Evaluation Method

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H04943
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Building structures/Materials
• Research Institution: Building Research Institute (2019); Tokyo Institute of Technology (2017-2018)
• Principal Investigator: Yamazaki Yoshihiro 国立研究開発法人建築研究所, 材料研究グループ, 主任研究員 (70644425)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 木造耐力壁 / 性能劣化 / 応答スペクトル / エネルギースペクトル / 等価減衰定数 / 累積損傷則

Outline of Final Research Achievements

Force and deformation capacity of timber shear walls is affected by loading protocol due to the fatigue behavior. Therefore, repeated severe earthquakes have a high possibility of increasing seismic damages of buildings even though they are designed following current design codes. This research proposes evaluation method of strength and equivalent damping ratio of timber shear walls subjected to various deformation history. Static loading tests and shaking table tests for wooden brace walls and plywood sheathing walls were conducted, and the behavior could be predicted by proposed formulae. Then, hysteresis model for time history analysis was proposed. The model could precisely trace the hysteresis loop, and analyze the maximum deformation of shaking table test. Finally, maximum response prediction method considering energy spectrum as well as response spectrum was also proposed. The prediction method could simulate the test results with acceptable accuracy.

Free Research Field

建築構造

Academic Significance and Societal Importance of the Research Achievements

現行の耐震設計では、限界耐力計算は最大応答を、エネルギー法は累積応答を設計規範としているが、実際の建築構造物の倒壊現象は、最大応答・累積応答の両者が関連付けられることが知られている。本研究では、累積応答による性能低下を考慮しつつ、最大応答を予測する既存設計法に展開する手法を提案しており、新たな設計規範を構築するための理論整備を行うことができた。本設計法は、一度大地震を継続した後の継続使用性、および残余性能の評価に活用することができ、地震後の経済的損失を抑えることに貢献できる。