2021 Fiscal Year Final Research Report
Experimental Study on Efficient Seismic Retrofitting using Ductile Knee Steel Braces for Timber Frame Joints
| Project/Area Number |
19K15081
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 22020:Structure engineering and earthquake engineering-related
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| Research Institution | Yamaguchi University (2020-2021)
Ishikawa National College of Technology (2019) |
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Principal Investigator |
Honma Sayuri 山口大学, 大学院創成科学研究科, 助教 (60772499)
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | 制震部材 / 方杖型 / 木質軸組 / 薄鋼鈑 |
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| Outline of Final Research Achievements |
In timber frame construction, it is common practice to use the shaft framework with diagonal bracings as bearing walls to resist horizontal loads during earthquakes excitations. The diagonal bracings are also applied to retrofit existing building frames seismically, but they have a disadvantage in preventing the openings in the exterior walls of the buildings. Therefore, the possibility of seismic reinforcement of the timber frames and retain the existing openings with knee bracings was investigated. In this study, a ductile steel knee brace, which were originally developed for steel building structures, were applied to existing timber residential buildings to determine their optimal shape.
Monotonic and cyclic loading tests were conducted on a ductile steel knee brace using thin steel plates, and nonlinear frame analysis was performed on a timber frame with a ductile knee brace, considering the joints of the timber frame, to investigate the effect of the ductile steel knee brace.
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| Free Research Field |
鋼構造
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| Academic Significance and Societal Importance of the Research Achievements |
これまでに、鋼構造に対して、損傷制御となる方杖型の制震部材の研究を行った結果、制震部材の導入により架構の耐力・剛性を極端に向上しないことが分かった。そこで、本研究では、主架構に損傷を与えずに主架構全体の剛性・耐力を向上させるため、薄鋼板を用いた方杖型の制震部材を木造軸組構造への適用を検討した。また、半剛接合となる仕口部の回転剛性を活用し、制震機能についても検討した。その結果、地震動による水平力を受けた際の木造軸組における仕口の回転変形（スリップ型の履歴）を活用し、木造軸組の架構に合わせて方杖部材の剛性・耐力を調整することで、同部材が早期に降伏し、ダンパーとしての機能を果たすことが分かった。
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