Compression Strength Adjustments for Moisture Content in Douglas-Fir Structural Lumber

Authors

  • J. D. Barrett
  • Wilson Lau

Keywords:

Moisture content, compression strength, structural lumber

Abstract

The effect of moisture content on the compression parallel to grain strength of Douglas-fir dimension lumber was evaluated using full-size on-grade members. Compression parallel to grain strength properties increased with drying throughout the entire property range.

The influence of moisture content on compression strength was observed to be strength level dependent. Linear and quadratic surface models are used to represent the relations between member moisture content and compression strength (or capacity) as a function of property level. Model parameters were derived using a Douglas-fir data set. Douglas-fir results are compared with the limited data available for the hem-fir and S-P-F commercial species groups. The comparisons suggest that the relationship between compression strength and moisture content is generally consistent for these species.

References

ASTM. 1988. American Society for Testing and Materials. Annual book of standard, vol. 04.09. Philadelphia, PA.nAplin, E. N., D. W. Green, J. W. Evans, and J. D. Barrett. 1986. Moisture content and the flexural properties of Douglas-fir dimension lumber. USDA Forest Service, Research Paper, FPL 475. Forest Prod. Lab., Madison, WI.nBarrett, J. D., and Wilson Lau. 1991. Bending strength adjustments for moisture content for structural lumber. Wood Sci. Technol. Vol. 25 (in press).nGreen, D. W. 1980. Adjusting the static strength of lumber for changes in moisture content. In D. E. Lyon and W. L. Galligan, co-ch. Proceedings of workshop on how the environment affects lumber design: Assessments and recommendations; May 28-30, 1980, Madison, Wisconsin. U.S. Department of Agriculture, Forest Service, Forest Products Laboratory.nGreen, D. W. 1989. Moisture content and the shrinkage of lumber. USDA Forest Serv. Research Paper, FPL-RP-489. Forest Prod. Lab., Madison, WI.nGreen, D. W., C. L. Link, A. L. DeBonis, and T. E. McLain. 1986. Predicting the effect of moisture content on the flexural properties of southern pine dimension lumber. Wood Fiber Sci. 18:134-156.nGreen, D. W., J. W. Evans, J. D. Barrett, and E. N. Aplin. 1988. Predicting the effect of moisture content on the flexural properties of Douglas-fir dimension lumber. Wood Fiber Sci. 20:107-131.nJessome, A. P., and S. B. Bellosillo. 1985. In-grade compression strength of Douglas-fir lumber-Final report. Forintek Canada Corp., Ottawa.nLittleford, T. W., and R. A. Abbott. 1978. Parallel-to-grain compressive properties of dimension lumber from western Canada. Information Report VP-X-180. Western Forest Products Laboratory, Vancouver.nMadsen, B. 1982. Recommended moisture adjustment factors for lumber stresses. Can. J. Civil Eng. 9(4):602-610.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 Forest Serv. Res. Pap. FPL 447. Forest Prod. Lab., Madison, WI.n

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Published

2007-06-28

Issue

Number 4 / October 1991

Section

Research Contributions

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