2011 Fiscal Year Final Research Report
Estimation of lateral resistance timber joints considering dynamic responsive characteristics
| Project/Area Number |
21380105
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Wood science
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| Research Institution | Hokkaido University |
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Principal Investigator |
HIRAI Takuro 北海道大学, 大学院・農学研究院, 教授 (20173205)
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| Co-Investigator(Kenkyū-buntansha) |
SAWATA Kei 北海道大学, 大学院・農学研究院, 助教 (10433145)
UEMATSU Takeyishi 北海道立総合研究機構, 建築研究本部・北方建築総合研究所・環境科学部, 研究員 (60462347)
TODA Masahiko 北海道立総合研究機構, 森林研究本部・林産試験場・性能部, 研究員 (60446317)
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| Project Period (FY) |
2009 – 2011
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| Keywords | 強度 / 木質構造 |
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| Research Abstract |
Dynamic tests of nailed joints are conducted under harmonic and white-noise waves. The principal results are as follows : (1)Dynamic response of nailed timber joints is clearly frequency dependent. (2)Under harmonic waves, nailed timber joints break in failure modes typical under static loading in resonance with the frequencies corresponding to safety limit stiffness. (3)Nailed timber joints once respond sensitively to the frequencies corresponding to damage limit stiffness, however, they do not break immediately in failure modes typical under static loading because of cyclic degradation. On the other hand, nailed timber joints may break in low-cyclic bending fatigue failure when they are subjected to many cycles, even if input accelerations are low. (4)The dynamic behavior above under harmonic waves is observed under white-noise waves consisting of similar frequency components. (5)Dynamic behavior of nailed shear walls, which are a model of multiple joint systems, behave in the same way as predicted from the behavior of single nailed joints. These test results show that the responsive characteristics of timber constructions vary due to change in equivalent stiffness along the static load-slip curves of single joints, structural subassemblies and whole structures. Test results also show that the low-cyclic bending fatigue failure of nails may lead timber constructions to critical collapse when the seismic forces act for many seconds and/or repeatedly, even if the maximum accelerations are below the damage limit.
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