Wood Design and Ultimate Strength

[Perception]

Hello everyone,

I'm new to LRFD Wood Design, and I can't find a good source that discusses the stress-strain curve of wood as it relates to ultimate strength. For steel one of the main additions in the introduction of LRFD was the use of ultimate strengths that looked at where the material ruptured. Has wood gone through a similar development where ASD capacities were based on the material yield point, but with LRFD the capacity of wood is based on rupture instead of yield? I realize that LRFD Wood Design accounts for all the other facets of the methodology (Load Factors, Strength Reduction Factors, etc.), but I can't find a source that definitively states whether LRFD Wood Design includes a transition from utilizing the yield point to utilizing the rupture point.

Thanks

 

[JAE]

In steel, ASD and LRFD both use yield points and ultimate rupture points in the derivation of strength.

In wood - I'm not sure they are using yield as I don't believe there is really a yield point in the wood significantly prior to the ultimate strength.
Rather, I think they provide "allowable" stresses in wood members based off the wood's ultimate strength.
In wood LRFD, they simply use the same failure points but with the safety factors used with phi and load factors.

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