Manual calculation method of embedment stiffness of partial compression parallel to the grain and its strength properties

We, in this article, propose a manual calculation method of the embedment stiffness of partial compression parallel to the grain. The calculation method was derived from the mechanical model based on the mechanics. The embedment displacement was thought as the series system, surface of the timber at the bearing parts, and timber deformation. The timber deformation was modeled using the mechanics, assuming the stress diffusion angle was 18 degree. The validity of the proposed calculation method was confirmed by the experimental results whose parameters were the size effect, the length of timber, and the edge distance of timber. Using the average stiffness of the each condition, the calculation stiffness and experimental results were good coincident. And the size effect factor of the embedment strength of partial compression parallel to the grain was derived from the experimental results.