Size Effects in Visually Graded Softwood Structural Lumber
Publication: Journal of Materials in Civil Engineering
Volume 7, Issue 1
Abstract
A unified size-effect model based on the weakest-link brittle fracture theory has been developed to represent statistical size effects in visually graded structural lumber. Test results from published studies and new results from a comprehensive study of strength properties of Canadian visually graded lumber have been used to develop the model parameters. Analyses have shown that size-effect factors are not statistically different across grades, species, or strength levels. For international harmonization of size-effect adjustment procedures for characteristic lumber strength properties, factors have been suggested for (1) Length and width effects for tension and bending members to equal 0.2; and (2) length and width effects for compression members to equal 0.1.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Barrett, J. D.(1974). “Effect of size on tension perpendicular to grain strength of Douglas-fir.”Wood and Fiber, 6(2), 126–143.
2.
Barrett, J. D., and Fewell, A. R. (1990). “Size factors for the bending and tension strength of structural lumber.”Proc., CIB Working Commission W18A—Timber Structures, Meeting 23, Conseil International de Batiment pour la Recherche, l'Etude et la Documentation (CIB).
3.
Barrett, J. D., Foschi, R. O., and Fox, S. P.(1975). “Perpendicular-to-grain strength of Douglas-fir.”Can. J. Civ. Engrg., 2(1), 50–57.
4.
Bohannan, B. (1966). “Effect of size on bending strength of wood members.”Res. Paper FPL 56, USDA Forest Service, Forest Products Lab., Madison, Wisc.
5.
Bury, K. V. (1976). Statistical models in applied science . John Wiley & Sons, Inc., New York, N.Y.
6.
Bury, K. V. (1979). Statistical analysis of NLGA tension tests . Dept. of Mech. Engrg., Univ. of British Columbia, Vancouver, Canada.
7.
Colling, F. (1986). “Influence of volume and stress distribution on the shear strength and tensile strength perpendicular to grain.”Proc., IUFRO Wood Engrg., Florence, Italy.
8.
Czmoch, I., Thelandersson, S., and Larsen, H. J. (1991). “Effect of within member variability on bending strength of structural lumber.”Proc., CIB Working Commission W18—Timber Structures: CIB-W18/24-6-3, Oxford, England.
9.
Foschi, R. O., Folz, B. R., and Yao, F. Z. (1989). “Reliability-based design of wood structures.”Struct. Res. Ser. Rep. No. 34, Dept. of Civil Engrg., Univ. of British Columbia, Vancouver, Canada.
10.
Foschi, R. O., and Barrett, J. D.(1976). “Longitudinal shear strength of Douglas-fir.”Can. J. Civ. Engrg., 3(2), 198–208.
11.
Green, D. W., and Evans, J. W. (1989). “Mechanical properties of visually graded lumber: Vol. I, a summary.”Publ. No. PB-88-159-389, Nat. Tech. Information Service, Springfield, Va.
12.
In-grade testing of structural lumber. (1989). Forest Products Research Society, Madison, Wisc.
13.
Johnson, L. A., Evans, J. W., and Green, D. W. (1989). “Volume effect adjustments for the in-grade data.”Ingrade testing of structural lumber, Forest Products Res. Society, Madison, Wisc.
14.
Kunesh, R. H., and Johnson, J. W.(1974). “Effect of size on tension strength of clear Douglas-fir and hem-fir dimension lumber.”Forest Products J., 24(8), 32–36.
15.
Lam, F., and Varoglu, E.(1990). “Effect of length on the tensile strength of lumber.”Forest Products J., 40(5), 37–42.
16.
Littleford, T. W. (1978). “Flexural properties of dimension lumber from western Canada.”Information Rep. VP-X-179, Western Forest Products Lab., Vancouver, Canada.
17.
Madsen, B.(1990). “Length effects in 38 mm spruce-pine-fir dimension lumber.”Can. J. Civ. Engrg., 17(2), 226–237.
18.
Madsen, B. (1992). Structural behavior of timber . Timber Engrg. Ltd., North Vancouver, B.C., Canada.
19.
Madsen, B., and Buchanan, A. H.(1986). “Size effects in timber explained by a modified weakest link theory.”Can. J. Civ. Engrg., 13(2), 218–232.
20.
Madsen, B., and Nielsen, P. (1976). “In-grade testing—size investigation on lumber subjected to bending.”Struct. Res. Ser. Rep. No. 15, Dept. of Civil Engrg., Univ. of British Columbia, Vancouver, Canada.
21.
Madsen, B., and Nielsen, P. (1978a). “In-grade testing: bending tests in Canada. June 1977–May 1978.”Struct. Res. Ser. Rep. No. 25, Dept. of Civ. Engrg., Univ. of British Columbia, Vancouver, Canada.
22.
Madsen, B., and Nielsen, P. (1978b). “In-grade testing: tension tests in Canada.”Prepared for National Lumber Grades Authority, Dept. of Civil Engrg., Univ. of British Columbia, Vancouver, Canada.
23.
Madsen, B., and Tomoi, M.(1991). “Size effects occurring in defect-free spruce-pine-fir bending specimens.”Can. J. Civ. Engrg., 18(4), 637–643.
24.
McGowan, W. M., Rovner, B., and Littleford, T. W. (1977). “Parallel-to-grain tensile properties of dimension lumber from several western Canadian species.”Information Rep. VP-X-172, Western Forest Products Lab., Vancouver, Canada.
25.
Schniewind, A. P., and Lyon, D. E.(1971). “Tensile strength of redwood dimension lumber—I: relation to grade and working stress.”Forest Products J., 21(7), 18–27.
26.
Sharp, D. J., and Suddarth, S. K.(1991). “Volumetric effects in structural composite lumber.”Proc., Int. Timber Engrg. Conf., London, England, 3, 427–433.
27.
Showalter, K. L., Woeste, F. E., and Bendsten, B. A. (1987). “Effect of length on the tensile strength of lumber.”Res. Paper FPL-RP-482, USDA Forest Service, Forest Products Lab., Madison, Wisc.
28.
Standard test methods for mechanical properties of lumber and wood-base structural material; D 4761–88. (1991). ASTM, Philadelphia, Pa.
29.
Weibull, W. (1939). “A statistical theory of the strength of materials.”Proc., Royal Swedish Inst., No. 151, Stockholm, Sweden.
Information & Authors
Information
Published In
Journal of Materials in Civil Engineering
Volume 7 • Issue 1 • February 1995
Pages: 19 - 30
Copyright
Copyright © 1995 American Society of Civil Engineers.
History
Published online: Feb 1, 1995
Published in print: Feb 1995
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.