ABSTRACT In this study, the reinforcement of wood by screws for partial compression perpendicular to the grain was studied. For the estimation of stiffness and strength, the reinforcement effect of screws depending on their position under the loading plate was evaluated by taking into account the internal displacement distribution of the wood. The finite element analysis (FEA) was used to investigate the internal displacement distribution of the wood. Then an approximate function that can be applied to various internal displacement distributions under loading plate was proposed. From the shear resistance mechanism between the screw and wood by taking their relative displacement distribution into consideration, the equations to estimate the initial stiffness and yield strength of the bearing performance of the wood reinforced by screws were derived. Then partial compression test was carried out for wood reinforced by screws with setting screw thread at various positions. The values obtained by the equations corresponded with the tendency of the experimental results. It was found that the screw reinforcement is more effective when its thread is positioned as much as distant from the contact surface.
Cite this paper
S. Murakami, A. Kitamori, K. Jung, I. Hassel and K. Komatsu, "Evaluation of Screw Reinforcement on Bearing Performance of Wood Depending on Screw Position," Open Journal of Civil Engineering, Vol. 2 No. 3, 2012, pp. 160-166. doi: 10.4236/ojce.2012.23021.
 T. Holmes and R. Harris, “Use of Non-Metallic Dowels to Control Vertical Movement in Platform Timber Frame Buildings,” Master’s Thesis, Bath University, 2011.
 I. Bejtka and H. J. Blass: “Self-Tapping Screws as Reinforcements in Beam Supports,” CIB-W18, Florence, Italy, 2006.
 I. Bejtka, “Verst?rkung von Bauteilen aus Holz mit Vollgewindeschrauben,” Band 2 der Reihe Karlsruher Berichte zum Ingenieurholzbau. Herausgeber, Karlsruhe University, Karlsruhe Germany, 2005 (In German).
 H. Tanahashi, H. Shimizu and Y. Suzuki, “Elastic Surface Displacements of Orthotropic Wood Due to Partial Compression Based on Pasternak Model,” Journal of Structural Construction Engineering, Vol. 609, 2006, pp. 129-136. (In Japanese).
 V. Z. Vlasov and N. N. Leont’ev, “Beams, Plates and Shell of Elastic Foundation,” Israel Program for Scientific Translations, 1966.
 B. Madsen, R. F. Hooley and C. P. Hall, “A Design Method for Bearing Stresses in Wood,” Canadian Journal of Civil Engineering, Vol. 9, No. 2, 1982, pp. 338-349.
 Forest Research Institute of Forestry Agency, “Handbook of Wood Industry,” Maruzen, Tokyo, 1982 (In Japanese).
 EN 408: 2003 Timber Structures. Structural Timber and Glued Laminated Timber, Determination of Some Physical and Mechanical Properties, 2006
 Architectural Institute of Japan, Standard for Structural Design of Timber Structures, Maruzen, Tokyo, 2006, pp. 108-109 (In Japanese).
 M. Karube, M. Harada and T. Hayashi, “A Proposal of Bi-Linear Modeling Tool for Assess Its Method and Problems in Common Tool for Load-Deformation Curves of Wooden Structures,” Digests of Annual Meeting of Architectural Institute of Japan, C-1, III, 2001, pp. 215-216 (In Japanese).