Elucidation of the mechanism of restoring force characteristics on screw joints in timber structures

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K18721
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Wood science
• Research Institution: Shizuoka University
• Principal Investigator: Kenji Kobayashi 静岡大学, 農学部, 准教授 (90576240)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 接合部 / 繰り返し加力 / 低サイクル疲労 / スクリュー / 木質構造

Outline of Final Research Achievements

In recent years, a self-tapping screw (STS) has come to be widely used in wood-based buildings. While the STSs have high strength, some STSs show brittle failure.
In this study, constant amplitude cyclic bending tests of STSs and nails were conducted and a good correlation between the amplitude and the number of cycles to failure was observed. In addition, we estimated the load-deformation characteristics of the joint taking into consideration the failure of the fasteners, and compared the value calculated by proposed estimation method with the experimental value, and the validity was confirmed. Furthermore, it was confirmed that the proposed estimation method can also be used for the evaluation of moment-resistance joints with screws.

Free Research Field

木質構造

Academic Significance and Societal Importance of the Research Achievements

日本は地震国であり、建築物は繰り返し作用する地震力に対して安全でなければならない。繰り返し加力による接合具の破壊はスクリューだけでなく他の接合具でも生じうるもので、適切な評価法が望まれてきた。
本成果を応用することにより、スクリューや釘などの接合具を用いた様々な接合部や構造要素の繰り返し履歴に対する特性を適切に把握することが可能となり、 安全な建築物の普及が期待される。