Analysis of Mechanically Laminated Timber Beams Using Shear Keys
Publication: Journal of Structural Engineering
Volume 137, Issue 1
Abstract
Small timber layers can be mechanically laminated into a larger timber cross section using shear keys to prevent slip between the layers. These mechanically laminated beams are commonly referred to as keyed beams and their use has a strong historical precedence. Current building codes and design standards do not provide adequate guidelines for the analysis of keyed beams. This project examined the applicability of an interlayer slip model to predict the partially composite behavior of the keyed beams. Solutions to the interlayer slip model for common loading configurations were developed, as were stiffness parameters for the semirigid wooden shear keys used to provide composite action. Small and full-scale testing of timber components was also performed to verify the interlayer slip model’s ability to predict the stiffness of specific keyed beam specimens. A comparison of the interlayer slip model to historical keyed beam test data was also conducted. The interlayer stiffness model, as well as the analytical shear key stiffness parameters, was able to accurately predict both the behavior for the full-scale keyed beams tested specifically for this research as well as the historic keyed beam behavior. Shear key configuration, moisture content, and clamping connector stiffness all played significant roles in the actual keyed beam stiffness.
Get full access to this article
View all available purchase options and get full access to this article.
References
American Forest and Paper Association (AF&PA). (2005). National design specification for wood construction, Washington, D.C.
ASTM. (2007). 2007 annual book of ASTM standards, 04.10 wood, Philadelphia.
Bodig, J., and Jayne, B. A. (1982). Mechanics of wood and wood composites, Van Nostrand Reinhold, New York.
Coduto, D. (2001). Foundation design, 2nd Ed., Prentice-Hall, Upper Saddle River, N.J.
Durm, J., and Esselborn, K. (1908). Lehrbuch des Hochbaues, Wilhelm Engelmann, Leipzig, Germany.
European Committee for Standardization (CEN). (2004). “Design of timber structures.” Eurocode 5, CEN, Brussels, Belgium.
Faella, C., Martinelli, E., and Nigro, E. (2002). “Steel and concrete composite beams with flexible shear connection: “Exact” analytical expression of the stiffness matrix and applications.” Comput. Struct., 80, 1001–1009.
Forchheimer, P. (1892). “Ueber zusammengesetzte Balken.” Z. Ver. Dtsch. Ing., 36, 100–103.
Forest Products Laboratory. (1999). Wood handbook, FPL-GTR-113, Madison, Wis.
Goodman, J. R. (1967). “Layered wood systems with interlayer slip.” Ph.D. dissertation, Univ. of California, Berkeley, Berkeley, Calif.
Goodman, J. R., and Popov, E. P. (1968). “Layered beam systems with interlayer slip.” J. Struct. Div., ST 11, 2535–2547.
Granholm, H. (1949). “Om sammansatta balkar och pelare med sarskild hansyn till spikade trakonstrucktioner.” Transactions, Vol. 88, Chalmers Tekniska Hogskolas Handlingar, Gottenburg, Sweden.
Jacoby, H. (1909). Structural details or elements of design in heavy framing, Wiley, New York.
Karlsen, G., and Slitsskouhov, Y. (1989). Wooden and plastic structures, A. B. Kuznetsov, translator, Mir Publishers, Moscow.
Karlsen, G. G. (1967). Wooden structures, W. L. Goodman, translator, Mir Publishers, Moscow.
Kidwell, E. (1898). “The efficiency of built-up wooden beams.” Trans. Am. Inst. Min., Metall. Pet. Eng., 1898, 977–993.
Leupold, J. (1726). Theatrum pontificiale: Oder Schauplatz der Bruecken und Bruecken-Baues, Christoph Zunkel, Leipzig, Germany.
Mahan, D. H. (1886). A treatise of civil engineering, Wiley, New York.
Miller, J. F. (2009). “Design and analysis of mechanically laminated timber beams using shear keys.” Ph.D. dissertation. Michigan Technological Univ., Houghton, Mich.
Newmark, N. M., Siess, C. P., and Viest, I. M. (1951). “Tests and analysis of composite beams with incomplete interaction.” Proc. Soc. Exp. Stress Anal., 9(1), 75–92.
Pleshkov, P. F. (1952). Teoriia rascheta dereviannykh sostavnnykh sterzhnei.
Rankine, W. J. M. (1889). A manual of civil engineering, 17th Ed., Charles Griffin & Company, London.
Ranzi, G., and Bradford, M. A. (2006). “Time-dependent analysis of composite beams with partial interaction using the direct stiffness approach.” UNICIV Rep. No. R-423, Univ. of New South Wales, Kensington, New South Wales, Australia.
Ranzi, G., and Bradford, M. A. (2007). “Direct stiffness analysis of a composite beam-column element with partial interaction.” Comput. Struct., 85, 1206–1214.
Ranzi, G., Gara, F., and Ansourian, P. (2006). “General method of analysis for composite beams with longitudinal and transverse partial interaction.” Comput. Struct., 84, 2373–2384.
Schnabl, S., Saje, M., Turk, G., and Planinc, I. (2007). “Analytical solution of two-layer beam taking into account interlayer slip and shear deformation.” J. Struct. Eng., 133(6), 886–894.
Strukel, M. (1900). Der Brückenbau, O. W. Backman, Kuopio, Finland.
Thelandersson, S., and Larsen, H. J. (2003). Timber engineering, Wiley, West Sussex, England.
Trautwine, J. C. (1862). Civil engineer’s pocket book, Wiley, New York.
Tredgold, T. (1820). Elementary principles of carpentry, E & FN Spon, London.
Wangaard, F. F. (1981). Wood: Its structure and properties, Penn State Univ., University Park, Pa.
Wheat, D. L., and Calixto, J. M. (1994). “Nonlinear analysis of two-layered wood members with interlayer slip.” J. Struct. Eng., 120(6), 1909–1929.
Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 137 • Issue 1 • January 2011
Pages: 124 - 132
Copyright
© 2011 ASCE.
History
Received: Sep 17, 2009
Accepted: Jul 10, 2010
Published online: Jul 15, 2010
Published in print: Jan 2011
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.