Further Experiments on Creep-Rupture Life Under Cyclic Environmental Conditions


  • Arno P. Schniewind
  • Duane E. Lyon


Pseudotsuga menziesii, elastic properties, creep rupture strength, load duration factor, moisture content, temperature


An increase in beam size from 10 by 20 mm to 2 by 2 inches increased the mean time to failure at a load level of 70% of modulus of rupture of specimens subjected to moisture content cycling by more than one order of magnitude. The effect of temperature cycling appears to depend on moisture content. The results indicate that the present load duration factor for wood is adequate under normal conditions, but that adjustments are needed when loaded members are small or when there are severe cyclic changes in ambient conditions.


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