Summary
Effects of moisture content on bending strength and section capacity have been studied assuming that strength properties are linearly related to moisture content below the fiber saturation point. The models developed using the linear strength vs. moisture content relationships are compared with quadratic models developed earlier. The linear representation of strength variation with moisture content leads to predicted member bending capacity relationships which show that increases in member bending strength with moisture content will compensate for section property decreases at all bending strength property levels. Comparisons of bending strength and bending capacity models show that the two modelling approaches lead to similar predicted member performance. Simplified procedures are provided for adjusting member bending strength for moisture content which are suitable for materials properties codes or standards.
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References
Aplin, N. E.; Green, D. W.; Evans, J. W.; Barrett, J. D. 1986: Moisture content and the flexural properties of Douglas-fir dimension lumber. USDA Forest Service, Research Paper, FPL 475. Madison WI: Forest Prod. Lab.
ASTM 1988: Establishing structural grades and related allowable properties for visually graded lumber. ASTM D245-81, Philadelphia PA
ASTM 1988: Standard method for evaluating allowable properties for grades of structural lumber. ASTM D2915-80. Philadelphia PA
Green, D. W. 1982: Adjusting the static strength of lumber for changes in moisture content. In: Proceed. Workshop on How the Environment Affects Lumber Design: Assessments and Recommendations., p 86–105. Madison WI: Forest Prod. Lab.
Green, D. W.; Link, C. L.; DeBonis, A. L.; McLain, T. E. 1986: Predicting the effect of moisture content on the flexural properties of southern pine dimension lumber. Wood Fiber Sci. 18: 134–156
Green, D. W.; Evans, J. W. 1987: Mechanical properties of visually graded lumber. Vol. 1. A Summary Report. NTIS, VA
Green, D. W.; Evans, J. W.; Barrett, J. D.; Aplin, E. N. 1988: Predicting the effect of moisture content on the flexural properties of Douglas-fir dimension lumber. Wood Fiber Sci. 20: 107–131
Green, D. W. 1989: Moisture content and the shrinkage of lumber. USDA Forest Serv. Research Paper, FPL-RP-489. Madison WI: Forest Prod. Lab.
Hoffmeyer, P. 1978: Moisture content-strength relationship for spruce lumber subjected to bending, compression and tension along the grain. In: Proceed. IUFRO — Wood Eng. Group Meeting, Vancouver B.C.
Jessome, A. P. 1971: The bending strength of lumber in structural sizes. Dept. of the Environment. Can. Forest Ser., Publication No. 1305. Ottawa
Madsen, B. 1975: Moisture content-strength relationships for lumber subjected to bending. Can. J. Civil Eng. 2: 466–473
Madsen, B.; Janzen, W.; Zwaagstra, J. 1980: Moisture effects in lumber. Struc. Research Series, Rep. No. 27. Dep. Civil Eng., Univ. of B. C., Vancouver
Madsen, B. 1982: Recommended moisture adjustment factors for lumber stresses. Can. J. Civil Eng. 9: 602–610
McLain, T. E.; DeBonis, A. L.; Green, D. W.; Wilson, F. J.; Link, C. L. 1984: The influence of moisture content on the flexural properties of southern pine dimension lumber. USDA Forest Serv. Res. Pap. FPL 447. Madison WI: Forest Prod. Lab.
Wilson, T. R. C. 1932: Strength-moisture relations for wood. US Forest Serv. Tech. Bull. No. 282. Madison WI: Forest Prod. Lab.
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Barrett, J.D., Lau, W. Bending strength adjustments for moisture content for structural lumber. Wood Sci.Technol. 25, 433–447 (1991). https://doi.org/10.1007/BF00225236
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DOI: https://doi.org/10.1007/BF00225236