Comparative Performance of Long-Term Loaded Wood Composite I-Beams and Sawn Lumber
Keywords:
I-beams, lumber, load duration, creep, composite wood assembliesAbstract
Solid sawn southern pine lumber (2 x 10 and 2 x 12) and wood composite I-beams having machine stress-rated southern pine flanges and composite panel webs (plywood, oriented strand board, and waferboard) were subjected to long-term loading in a stable hygrothermal environment and then destructively tested so that residual load-deflection characteristics could be measured. A 4-element viscoelastic model was fitted to the creep data on a specimen-by-specimen basis. Load history had a minor effect on the stiffness performance of I-beams, but did not influence load capacity or deflection at maximum load. Large variations in the lumber data obscured the subtle effects a load history might impose. Failure modes and locations in destructively tested specimens indicated that load history did not play a role in the ultimate failure mechanism.References
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