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Official Journal of the Japan Wood Research Society

Journal of Wood Science Cover Image
  • Open Access

Estimation of stiffness and strength in timber knee joints with adhesive and verification by experiment

Journal of Wood ScienceOfficial Journal of the Japan Wood Research Society200652:802

  • Received: 22 October 2004
  • Accepted: 18 November 2005
  • Published:


The use of adhesive joints is gradually increasing, especially those with glued-in steel rods (GIRs). There are, however, some problems with the design methods when used for moment-transmitting applications. In this article, design methods for GIRs and cross-lapped glued joints (CLJs) are proposed. For CLJs, we made a hypothesis that both rotational deformation of CLJ and stress of the glue line occurred with bending and shearing deformation of the timber. Using this hypothesis and Kelvin’s theorem, a mechanical model of CLJ is proposed. For GIRs, the axial stress component of the rod and the lateral stress component of the rod were taken into account using the theory of a beam on an elastic foundation. From the comparisons between calculations and experimental results, it was recognized that the stiffness and strength of CLJs and GIRs could be predicted precisely using our proposed models.

Key words

  • Glued-in rod
  • Knee joint
  • Timber
  • Crosslapped joint
  • Mechanical model