Lumber Property Relationships for Engineering Design Standards
Keywords:
Modulus of rupture, modulus of elasticity, ultimate tensile stress, ultimate compression stress, coefficient of variationAbstract
Data from the In-Grade Testing Program for visually graded dimension lumber are used to identify lumber property relationships for engineering design standards. The properties studied are modulus of rupture (MOR), modulus of elasticity (MOE), ultimate tensile stress parallel to grain (UTS), and ultimate compression stress parallel to grain (UCS). The relationships identified between UCS and either MOR or UTS vary little with species, lumber grade, and lumber width. The data show a closer relationship between UCS and MOR than between UTS and MOR. The historical basis for assigning allowable properties to machine stress-rated (MSR) lumber is reviewed. The UCS-MOR and UTS-MOR relationships presented in the paper are shown to be consistent with historical data obtained with visually graded lumber but different from relationships currently assumed for MSR lumber. The effects of species, moisture content, test span, lumber width, and presence or absence of pith on strength property relationships are discussed. Strength property relationships are shown to be a result of inherent growth characteristics of the lumber. Finally, a procedure is provided for estimating coefficient of variation as a function of grade that may be useful in reliability-based engineering design standards.References
Aplin, E. N., D. W. Green, J. W. Evans, and J. D. Barrett. 1986. The influence of moisture content on the flexural properties of Douglas-fir dimension lumber. Res. Pap. FPL 475. U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. Madison, WI.nASTM. 1989. Designations D198-84 (p. 80), D245-88 (p. 99), D2555-88 (p. 368), D2915-88 (p. 404), and D4761-88 (p. 507). Annual Book of ASTM Standards, Wood, vol. 04.09. American Society for Testing and Materials, Philadelphia. PA.nBarrett, J. D., and H. Griffin. 1989. Size effect and property relationship for Canadian 2-inch dimension lumber. Proceedings of CIB W18A, Berlin, German Democratic Republic.nCanadian Wood Council. 1988. Mechanical properties of visually graded lumber: A summary. Ottawa, Ontario. 38 pp.nCurry, W. T., and A. R. Fewell. 1977. The relations between the ultimate tension and ultimate compression strength of timber and its modulus of elasticity. Building Research Establishment, Current Paper CP 22/77. Princes Risborough Laboratory, Aylesbury, Bucks, England.nDoyle, D. V., and L. J. Markwardt. 1966. Properties of southern pine in relation to strength grading of dimension lumber. Res. Pap. FPL 64. U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, Madison, WI.nDoyle, D. V., and L. J. Markwardt. 1967. Tension parallel-to-grain properties of southern pine dimension lumber. Res. Pap. FPL 84. U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, Madison, WI.nEvans, J. W., R. E. Johnson, and D. W. Green. 1984. Estimating the correlation between variables under destructive testing: Or how to break the same board twice. Technometrics 26(3):278-297.nFewell, A. R. 1989. Stress classes for structural lumber. Fourth draft of CEN standard xxx2. Document CEN/TC/WG 2 N66E. British Standards Institute.nGalligan, W. L., C. C. Gerhards, and R. L. Ethington. 1979. Evolution of tensile design stresses for lumber. Gen. Tech. Rep. FPL 28. U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, Madison, WI.nGerhards, C. C., and R. L. Ethington. 1974. Evaluation of models for predicting tensile strength of 2- by 4-inch lumber. Forest Prod. J. 24(12):46-54.nGlos, P., and A. R. Fewell. 1989. The determination of characteristic values of mechanical properties and density of timber. Fourth draft of CEN standard xxxl. Document CEN/TC/WG 2 N66E. British Standards Institute.nGreen, D. W., and J. W. Evans. 1987. Mechanical properties of visually graded lumber. Volume 1: A summary. Publication PB-88-159-389. National Technical Information Service, U.S. Department of Agriculture, Springfield, VA.nGreen, D. W., and J. W. Evans. 1988. Evaluating lumber properties: Practical concerns and theoretical restraints. Proceedings of the 1988 International Conference on Timber Engineering. Pages 203-217 in R. Y. Itani, ed. Weston Hotel, Seattle, WA, September 19-22.nGreen, D. W., and D. E. Kretschmann. 1989. A discussion of lumber property relationships in Eurocode 5. Proceedings of CIB W18A, Berlin, German Democratic Republic.nGreen, D. W., and D. E. Kretschmann. 1990. Stress class systems: An idea whose time has come. Res. Pap. FPL 500, U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, Madison, WI.nGreen, D. W., B. E. Shelley, and H. P. Vokey, eds. 1989. Proceedings: In-grade testing of structural lumber. Forest Products Laboratory, April 1988, Proceedings 47363. Forest Products Research Society, Madison, WI.nGreen, D. W., R. F. Pellerin, J. W. Evans, and D. E. Kretschmann. 1990. Moisture content and the tensile strength of Douglas-fir dimension lumber Res. Pap. FPL 497. U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, Madison, WI.nHoyle, R. J. 1968. Background to machine stress grading. Forest Prod. J. 18(4):87-98.nJohnson, L. A., J. W. Evans, and D. W. Green. 1989. Volume effect adjustments of the in-grade data. D. W. Green, B. E. Shelley and H. P. Vokey, eds. Pages 56-67 in Proceedings: In-grade testing of structural lumber. Forest Products Laboratory, April, 1988, Proceedings 47363. Forest Products Research Society, Madison, WI.nMcKean, H. B., and R. J. Hoyle. 1964. Stress-grading method for dimension lumber. ASTM Special Technical Publication 353. American Society for Testing and Materials, Philadelphia, PA.nMcLain, T. E., A. L. De Bonis, D. W. Green, F. J. Wilson, and C. L. Link. 1984. The influence of moisture content on the flexural properties of southern pine dimension lumber. Res. Pap. FPL 447. U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, Madison, WI.nMurphy, J. F. Chair. 1988. Load and resistance factor design for engineered wood construction. ASCE prestandard report. March. American Society of Civil Engineers, New York, NY.nOrosz, I. 1968. Some nondestructive parameters for prediction of strength of structural lumber. Res. Pap. FPL 100. U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, Madison, WI.nTsehaye, A., J. C. F. Walker, and A. H. Buchanan. 1989. In-grade testing of juvenile wood. Pages 87-91 in Proceedings of the Second Pacific Timber Engineering Conference. University of Auckland, New Zealand. August 28-31, Centre for Continuing Education, U. of Auckland, vol. I.nUSDA. 1987. Wood handbook: Wood as an engineering material. Agric. Handb. 72. U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, Madison, WI.nWWPA. 1981. Standard lumber grading rules. Western Wood Products Association, Portland, OR.n
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