| Summary: | The Canadian lumber industry undertook two large-scale test
programs for the verification of lumber design properties of
Canadian species combinations. The visual lumber in-grade test
program was begun in 1983 (with a prior program undertaken in
1975), while a similar program for machine graded lumber (MSR
lumber) was undertaken in 1988. Some of the results of the MSR
lumber in-grade test program are examined in this thesis.
Stiffness and strength results from the visual lumber in-grade
program are used for comparison, as are values from the MSR
lumber standard.
The importance of differences in methods of testing
properties, particularly Modulus of Elasticity (MOE), is
shown. Differences in results occur due to changes in the test
span to depth ratios, measurement techniques and location of
defects.
The importance of knots as a cause of failure in both bending
and tension is examined. The high incidence of lumber failures
initiating at points where no defect was visible to the human
eye is also studied. === Forestry, Faculty of === Graduate
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