Moisture Effects on Load-Duration Behavior of Lumber. Part I. Effect of Constant Relative Humidity

Authors

  • Kenneth J. Fridley
  • R. C. Tang
  • Lawrence A. Soltis

Keywords:

Load-duration, failure, relative humidity, moisture content, lumber

Abstract

The effect of moisture content on the load-duration behavior for structural lumber is presented. Select Structural and No. 2 Douglas-fir 2 by 4 specimens were tested in bending at relative humidities (RH) of 35%, 50%, and 95% with a constant temperature of 73 F maintained during the tests. Constant loads based on the 15th percentile of the static strength distribution for each grade at 73 F and 50% RH were used to load the beams. The results indicate a trend toward shorter times-to-failure at higher moisture contents subjected to equal mechanical stress ratios. The effect, however, was no more evident in the No. 2 grade specimens than in the Select Structural specimens. Survival rates were likewise reduced at higher humidities.

References

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Published

2007-06-28

Issue

Number 1 / January 1991

Section

Research Contributions

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