Predicting the Effect of Moisture Content on the Flexural Properties of Southern Pine Dimension Lumber

Authors

  • David W. Green
  • Carol L. Link
  • A. Louis DeBonis
  • Thomas E. McLain

Keywords:

Analytical models, mechanical properties, bending, moisture content, dimension lumber

Abstract

Current procedures for adjusting lumber properties for changes in moisture content are based on trends observed with the mean properties. This study was initiated to develop analytical procedures for adjusting the flexural properties of 2-inch-thick southern pine dimension lumber applicable to all grades and sizes as well as all levels of the cumulative frequency distribution. Equations are derived for adjusting modulus of rupture (MOR), modulus of elasticity (MOE), moment capacity (RS), and flexural stiffness (EI) for changes in moisture content. The best of these equations are significantly more accurate than current procedures for adjusting strength properties (MOR and RS). Because MOE and EI are less affected by changes in moisture content, most of the equations, including the current American Society for Testing and Materials procedure, work well for these properties.

References

American Society for Testing and Materials. 1930. Standard specifications for structural wood joist and planks, beams and stringers, and posts and timbers. ASTM D 245-30. Philadelphia, PA.nAmerican Society for Testing and Materials. 1974. Standard method for evaluating allowable properties for grades of structural lumber. ASTM D 2915-74. Philadelphia, PA.nAmerican Society for Testing and Materials. 1984. Establishing structural grades and related allowable properties for visually-graded lumber. ASTM D 245-81. Philadelphia, PA.nAplin, N. E., D. W. Green, J. W. Evans, and J. D. Barrett. 1985. The influence of moisture content on the flexural properties of Douglas-fir dimension lumber. Manuscript in preparation. USDA For. Serv., For. Prod. Lab., Madison, WI.nCline, M., and A. L. Heim. 1912. Tests of structural timbers. USDA Forest Serv. Bull. No. 108. For. Prod. Lab., Madison, WI.nGalligan, W. L., D. W. Green, D. S. Gromala, and J. H. Haskell. 1980. Evaluation of lumber properties in the United States and their application to structural research. For. Prod. J. 30(10):45-51.nGerhards, C. C. 1968. Four-inch southern pine lumber: Seasoning factors for modulus of elasticity and modulus of rupture. For. Prod. J. 18(11):27-35.nGerhards, C. C. 1970. Further report on seasoning factors for modulus of elasticity and modulus of rupture. For. Prod. J. 20(5):40-44.nGreen, D. W. 1982. Adjusting the static strength of lumber for changes in moisture content. Proceedings, Workshop on how the environment affects lumber design: Assessments and recommendations. For. Prod. Lab., Madison, WI., May 28-30, 1980.nGreen, D. W. 1983. In-grade testing: Impetus for change in the utilization of structural lumber. Proceedings of the conference. From stump thru mill: Recent advances in spruce-fir utilization technology. University of Maine at Orono, August 17-19.nHoffmeyer, P. 1978. Moisture content-strength relationship for spruce lumber subjected to bending, compression, and tension along the grain. Proceedings, IUFRO wood engineering group meeting, Vancouver, B.C. Pp. 72-91.nMadsen, B. 1975. Moisture content-strength relationship for lumber subjected to bending. Canadian J. Civil Eng. 2(4):466-473.nMadsen, B. 1982. Recommended moisture adjustment factors for lumber stresses. Canadian J. Civil Eng. 9:602-610.nMadsen, B., W. Janzen, and J. Zwaagstra. 1980. Moisture effects in lumber. Structural Research Series, Rep. No. 27. Dept. Civil Eng,. University of British Columbia, Vancouver.nMcLain, T. E., A. L. DeBonis, 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. USDA For. Serv. Res. Pap. 447. For. Prod. Lab., Madison, WI.nUnited States Forest Products Laboratory. 1974. Wood handbook: Wood as an engineering material. USDA Agr. Handb. 72, rev. U.S. Department of Agriculture.nWilson, T. R. C. 1932. Strength-moisture relations for wood. Technical Bulletin No. 282. U.S. Department of Agriculture.n

Downloads

Published

2007-06-28

Issue

Number 1 / January 1986

Section

Research Contributions

License

The copyright of an article published in Wood and Fiber Science is transferred to the Society of Wood Science and Technology (for U. S. Government employees: to the extent transferable), effective if and when the article is accepted for publication. This transfer grants the Society of Wood Science and Technology permission to republish all or any part of the article in any form, e.g., reprints for sale, microfiche, proceedings, etc. However, the authors reserve the following as set forth in the Copyright Law:

1. All proprietary rights other than copyright, such as patent rights.

2. The right to grant or refuse permission to third parties to republish all or part of the article or translations thereof. In the case of whole articles, such third parties must obtain Society of Wood Science and Technology written permission as well. However, the Society may grant rights with respect to Journal issues as a whole.

3. The right to use all or part of this article in future works of their own, such as lectures, press releases, reviews, text books, or reprint books.