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2005 Fiscal Year Final Research Report Summary

Study on the Optimum design of Steel Washers for Timber.

Research Project

Project/Area Number 16580128
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 林産科学・木質工学
Research InstitutionIwate University

Principal Investigator

TSUJINO Tetsuji  Iwate University, Faculty of Education, professor, 教育学部, 教授 (20003965)

Co-Investigator(Kenkyū-buntansha) HIRAI Takuro  Hokkaido University, Graduate School of Agriculture, professor, 大学院・農学研究科, 教授 (20173205)
Project Period (FY) 2004 – 2005
KeywordsWasher / Embedment / RBSM
Research Abstract

In practical design, allowable or working bolt-withdrawal resistance does not come from tensile resistance or allowable elongation of bolts but mostly comes from allowable embedment of steel washers into timber. Embedding resistance of steel washers or side plates also has a positive effect on the ultimate lateral resistance of bolted joints. It is because their embedding stiffness causes the secondary axial forces of the bolts that increase the ultimate lateral resistance and ductility of the bolted joints.
In this study, load-embedment relationships of steel washers into timber are analyzed applying the "Rigid Bodies-Springs Model", which is an analytical model proposed by T.Kawai. In the analyses, a steel washer on timber is regarded as a plate on a foundation. This plate is assumed to consist of finite rigid elements connected with finite spring elements supported on external springs normal to the plate. This modeling can also be applied to estimate the plate-bending deformation of steel side plates of bolted joints. Bearing spring constants of timber under rigid blocks must be given for each joint configuration because the bearing stiffness are affected by margins and depths of timber. Then, the bearing constants are calculated introducing a concept of "effective foundation width" derived from the previous results of partial bearing tests considering various margins and depths.
Plate-bending deformation of steel square washers supported on timber and their embedment into timber are analyzed using the bearing spring constants calculated based on the "effective foundation width". The analyzed results are verified with washer-timber bearing tests with steel square washers of nine combinations of three kinds of width and three kinds of thickness.
Then some knowledges were obtained by simulation based on numerical analysis.

  • Research Products

    (4 results)

All 2006 2004 Other

All Journal Article (4 results)

  • [Journal Article] Steel Washers on Timber2006

    • Author(s)
      Takuro Hirai, Tetsuji Tsujino, Yoshihisa Sasaki
    • Journal Title

      Proc. of the 9th World Conference on Timber Engineering 2006, Portland

      Pages: a schedule

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] ワッシャのめり込みに関する研究2004

    • Author(s)
      辻野哲司, 平井卓郎, 竹内則雄
    • Journal Title

      第54回日本木材学会研究発表要旨集

      Pages: 110

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Study on Embedment of Steel Washers2004

    • Author(s)
      Tetsuji Tsujino, Takuro Hirai, Norio Takeuchi
    • Journal Title

      Abstracts of the 54^<th> Annual Meeting of the Japan Wood Research Society

      Pages: 110

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Steel Washers on Timber.

    • Author(s)
      Takuro Hirai, Tetsuji Tsujino, Yosihisa Sasaki
    • Journal Title

      Proc.of the 9th World Conference on Timber Engineering 2006 Portland. (We are scheduled to give a presentation at the conference.)

    • Description
      「研究成果報告書概要(欧文)」より

URL: 

Published: 2007-12-13  

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