Effect of Lamination Anisotropy and Lay-Up in Glued-Laminated Timbers
Publication: Journal of Structural Engineering
Volume 131, Issue 7
Abstract
This paper presents the analysis of glued-laminated timbers (glulam) subjected to tension perpendicular to the fiber direction, hereby taking into account the cylindrical anisotropy of the individual laminations and specific lay-up configurations. The investigations include two- and three-dimensional finite element analyses of prismatic specimens and curved beams. The influences of the board width and the location of the board’s material coordinate system, i.e., of the sawing pattern, were studied parametrically. The stress distributions obtained deviate considerably from results based on simplified orthotropic constitutive theory, which is commonly applied in the analysis of glulam. The study showed a strong influence of the lamination sawing pattern and of the grouping within the glulam cross section. The maximum stress values exceeded the stresses obtained assuming rhombic orthotropy by a factor of about 2–4. The strength relevant Weibull stresses, which smooth the true uneven stress distributions, revealed increases of about 1.4–1.9. This work provides enhanced understanding of glued-laminated timbers in transverse tension loading and can be used as a theoretical tool for optimization of lay-ups.
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Acknowledgment
The financial support of the Deutsche Forschungsgemeinschaft via a grant to Sonderforschungsbereich 381, subproject A8 “Damage and non-destructive testing of the natural fiber composite material wood” is gratefully acknowledged.
References
Aicher, S., and Dill-Langer, G. (1996). “Influence of cylindrical anisotropy of wood and loading conditions on off-axis stiffness and stresses of a board in tension perpendicular to the grain.” Otto-Graf J., 7, 216–242.
Aicher, S., and Dill-Langer, G. (1997a). “Climate induced stresses perpendicular to the grain in glulam.” Otto-Graf J., 8, 209–231.
Aicher, S., and Dill-Langer, G. (1997b). “DOL effect in tension perpendicular to the grain of glulam depending on service classes and volume.” Proc., CIB W18, Meeting 30, 30-9-1, Vancouver, Canada.
Aicher, S., Dill-Langer, G., and Höfflin, L. (2001). “Effect of polar anisotropy of wood loaded perpendicular to grain.” J. Mater. Civ. Eng., 13(1), 2–9.
Aicher, S., Dill-Langer, G., and Ranta-Maunus, A. (1998). “Duration of load effect in tension perpendicular to the grain of glulam in different climates.” Holz Roh-Werkst., 56(5), 295–305.
Barrett, J. D. (1974). “The effect of size on tension perpendicular-to-grain strength of Douglas-Fir.” Wood Fiber Sci., 6, 126–143.
Barrett, J. D., Foschi, R. O., and Fox, S. P. (1975). “Perpendicular-to grain strength of Douglas-Fir.” Can. J. Civ. Eng., 2(1), 50–57.
Buchmann, W. (1969). “Berechnung polarorthotroper Kreisbogenscheiben konstanter Dicke unter reiner Biegebeanspruchung.” Bautechnik, 1, 27–32 (in German).
Dahlblom, O., and Ormarsson, S. (1993). “Analysis of stress distribution.” Fiber reinforcement of glulam: Summary and report 1-7, Report TVSM-7083, Div. Struc. Mech., University of Lund, Sweden.
Dill-Langer, G. (2004). “Schädigung von Brettschichtholz bei Beanspruchung rechtwinklig zur Faserrichtung.” PhD thesis, Otto-Graf-Institute, University of Stuttgart, Germany (in German).
Ehlbeck, J., and Kürth, J. (1994). “Verteilung der Querzugspannungen in gekrümmten Satteldachträgern unter Streckenlast und Vergleich mit dem vereinfachten Verfahren nach DIN ENV 1995, Teil 1-1.” Research Rep., Versuchsanstalt für Stahl, Holz und Steine, Univ. of Karlsruhe, Germany (in German).
Foschi, R. O. (1970). “Point-matching analysis of curved timber beams.” J. Struct. Div. ASCE, 96(1), 35–48.
Foschi, R. O., and Fox, S. P. (1970). “Radial stresses in curved timber beams.” J. Struct. Div. ASCE, 96(10), 1997–2008.
Hanhijärvi, A., and Ranta-Maunus, A. (1996). “Computational analysis of the effect of transverse anisotropy and annual ring pattern in cross-sections of curved glulam beams on the size effect of strength.” European Workshop on Application of Statistics and Probabilistics in Wood Mechanics, Bordeaux, France.
Hoffmeyer, P., Damkilde, L., and Pedersen, T. N. (2000). “Structural timber and glulam in compression perpendicular to grain.” Holz Roh-Werkst., 58, 73–80.
Larsen, H. J. (2003). “Design of structures based on glulam, LVL and other timber products.” Timber engineering, S. Thelanderson and H. J. Larsen, eds., Wiley, New York.
Ranta-Maunus, A. (1996). “The influence of changing state of stress caused by mechano-sorptive creep on the duration of load effect.” Proc., Int. Conf. Wood Mech., Stuttgart, Germany, 187–201.
Ranta-Maunus, A. (1998). “Duration of load effect in tension perpendicular to grain in curved glulam.” Proc., CIB W18, Meeting 31, 31-9-1.
Wilson, T. R. C. (1939). “The glued-laminated wooden arch.” U.S. Dept. Agr. Tech. Bull. No. 691, Washington, D.C.
Wood handbook. Wood as an engineering material. (1999). Forest Products Society, Madison, Wis.
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© 2005 ASCE.
History
Received: Dec 26, 2000
Accepted: Dec 20, 2004
Published online: Jul 1, 2005
Published in print: Jul 2005
Notes
Note. Associate Editor: J. Daniel Dolan
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