Predicting the Effective Flange Width of a CLT Slab in Timber Composite Beams
Publication: Journal of Structural Engineering
Volume 144, Issue 7
Abstract
A timber composite beam consists of a cross-laminated timber (CLT) panel attached to a girder such as a laminated veneer lumber (LVL) beam. Under positive bending moment, part of the CLT panel acts as the flange of the LVL girder and resists compression. When the spacing between LVL girders becomes large, simple beam theory is not applicable because the compressive stresses in the flange vary with the distance from the LVL girder web, and the flange area over the web is more highly stressed than the extremities. This phenomenon is termed shear lag. For the design of steel-concrete composite sections, the effective flange width concept has been introduced into national and international design specifications. Despite the large number of studies regarding steel and concrete composite structures, comparative, comprehensive research has not been conducted on timber composite structures. In this study, a numerical model is developed and experimentally validated for analyzing different configurations of timber composite beams. Based on a parametric study, a formula is proposed for determining the effective flange width of timber composite beams.
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Acknowledgments
The authors would like to thank the laboratory technicians Mark Byrami and Andrew Virtue for their contribution in preparing the test setup. Gratitude is extended to Milad Naghibi, Daniel Lowe, and Soroosh Haji Hosseinnejad for providing ideas and support with ABAQUS. Finally, the authors thank photographer and graphic designer Nariman Valizadeh and Navid Masoudnia for providing great photos and figures.
References
Fahmy, E. H., and Robinson, H. (1985). “Effective slab widths for simple composite beams with ribbed metal deck.” Model. Simul. Control B, 3(1), 19–36.
AASHTO. (1998). AASHTO LRFD bridge design specifications, 2nd Ed., Washington, DC.
ABAQUS [Computer software]. Dassault Systemes Simula Corp., Providence, RI.
ACI (American Concrete Institute). (2002). “Building code requirements for reinforced concrete.”, Farmington Hills, MI.
Adekola, A. O. (1968). “Effective widths of composite beams of steel and concrete.” Struct. Eng., 46(9), 285–289.
Adekola, A. O. (1974). “The dependence of shear lag on partial interaction in composite beams.” Int. J. Solids Struct., 10(4), 389–400.
Ahn, I. S., Chiewanichakorn, M., Chen, S. S., and Aref, A. J. (2004). “Effective flange width provisions for composite steel bridges.” Eng. Struct., 26(12), 1843–1851.
AISC. (2001). Manual of steel construction: Load and resistance factor design, Chicago.
Amadio, C., and Fragiacomo, M. (2002). “Effective width evaluation for steel-concrete composite beams.” J. Constr. Steel Res., 58(3), 373–388.
Ardalany, M., Fragiacomo, M., Moss, P., and Deam, B. (2013). “An analytical model for design of reinforcement around holes in laminated veneer lumber (LVL) beams.” Mater. Struct., 46(11), 1811–1831.
Aref, A. J., Chiewanichakorn, M., Chen, S. S., and Ahn, I. S. (2007). “Effective slab width definition for negative moment regions of composite bridges.” J. Bridge Eng., 339–349.
Bodig, J., and Jayne, B. A. (1993). Mechanics of wood and wood composites, Krieger, Malabar, FL.
BSI (British Standard Institution). (1994). “Design of composite steel and concrete structures. Part 2: Composite bridges and Part 1.1, general rules and rules for buildings.” DD ENV 1994-2:2001, Eurocode 4, London.
Buchanan, A. (1999). Timber design guide, New Zealand Timber Industry Federation, Wellington, New Zealand.
Castro, J. M., Elghazouli, A. Y., and Izzuddin, B. A. (2007). “Assessment of effective slab widths in composite beams.” J. Constr. Steel Res., 63(10), 1317–1327.
Chen, S. S., Aref, A. J., Chiewanichakorn, M., and Ahn, I. S. (2007). “Proposed effective width criteria for composite bridge girders.” J. Bridge Eng., 325–338.
Chiewanichakorn, M., Aref, A. J., Chen, S. S., and Ahn, I. S. (2004). “Effective flange width definition for steel-concrete composite bridge girder.” J. Struct. Eng., 2016–2031.
CSA (Canadian Standards Association). (2001). “Limit state design of steel structures.” CAN/CSA-S16-01, Rexdale, Canada.
Davalos, J. F., and Salim, H. A. (1993). “Effective flange width for stress-laminated T-system timber bridges.” J. Struct. Eng., 938–953.
Elkelish, M. S., and Robinson, H. (1986). “Longitudinal cracking of composite beams with ribbed metal deck.” Can. J. Civ. Eng., 13(6), 733–740.
Gagnon, S., and Pirvu, C. (2011). CLT handbook: Cross-laminated timber, AISC, Chicago.
Gilun, A., and Meronk, J. (2006). “Stress-laminated timber T-beam and box-beam bridges.” Master’s thesis, Chalmers Univ. of Technology, Gothenburg, Sweden, 141.
Heins, C. P., and Fan, H. M. (1976). “Effective composite beam width at ultimate load.” J. Struct. Div. ASCE, 102(11), 2163–2179.
Mackey, S., and Wong, F. K. C. (1961). “Effective width of composite tee-beam flang.” Struct. Eng., 39(9), 277–285.
Masoudnia, R., Hashemi, A., and Quenneville, P. (2016). “Evaluation of effective flange width in the CLT composite T-beams.” Proc., World Conf. on Timber Engineering, Vienna Univ. of Technology, Vienna, Austria.
Masoudnia, R., and Quenneville, P. (2013). “Stub girder flooring system for timber construction.”, Univ. of Auckland, Auckland, New Zealand.
Masoudnia, R., and Quenneville, P. (2014). “Stub girder flooring system for timber construction.” Proc., World Conf. on Timber Engineering, Quebec.
Metzer, W. (1929). “Die mittragende breite.” Luftfahrtforschung, 4, 1–20 (in German).
Miller, A. B. (1929). “The effective width of a plate supported by a beam.”, Institution of Civil Engineers, London.
Nassif, H., Abu-Amra, T., and El-Tawil, S. (2005). “Effective flange width criteria for composite steel girder bridges.” Proc., Transportation Research Board 84th Annual Meeting, Transportation Research Board, Washington, DC.
Ozelton, E., and Baird, J. (2008). Timber designers’ manual, C. L. Staples, London.
Pearson, H., Evernden, M., and Harris, R. (2012). “Analysis of engineered timber panels using a strut and tie model for use in folded plate structures and deep beams.” Proc., World Conf. on Timber Engineering, P. Quenneville, ed., Vol. 9, New Zealand Timber Design Society, Auckland, New Zealand, 344–353.
Popovski, M., and Karacabeyli, E. (2012). “Seismic behavior of cross-laminated timber structures.” Proc., World Conf. on Timber Engineering, New Zealand Timber Design Society, Auckland, New Zealand.
Porteous, J., and Kermani, A. (2013). Structural timber design to Eurocode 5, Wiley, Chichester, U.K.
Salama, T., and Nassifb, H. (2011). “Effective flange width for composite steel beams.” J. Eng. Res., 8(1), 28–43.
Timoshenko, S., and Gere, J. (2009). Theory of elastic stability, Courier Dover Publications, Mineola, NY.
Yam, L. C. P., and Chapman, J. C. (1968). “The inelastic behavior of simply supported composite beams of steel and concrete.” Proc. Inst. Civ. Eng., 41, 651–683.
Zou, B., Chen, A., Davalos, J. F., and Salim, H. A. (2011). “Evaluation of effective flange width by shear lag model for orthotropic FRP bridge decks.” Comp. Struct., 93(2), 474–482.
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Published In
Journal of Structural Engineering
Volume 144 • Issue 7 • July 2018
Copyright
©2018 American Society of Civil Engineers.
History
Received: Oct 1, 2016
Accepted: Aug 25, 2017
Published online: May 8, 2018
Published in print: Jul 1, 2018
Discussion open until: Oct 8, 2018
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