Steel Ultimate Stress Range

[abusementpark]

Does anyone know why some steel specifications in the AISC manual give a range for the ultimate stress range( i.e. 58-80), but some specs only give a specific number for the ultimate stress?

 

[JStephen]

I'm not sure I understand the question. But anyway, some steel specifications (such as A36, if I remember right) give only a minimum ultimate strength, while others give a minimum and a maximum. I'm not sure of why that is the case. I assume the maximum is actually to help make sure toughness and weldability are reasonable, not so much that high strength by itself is undesirable. And, I haven't checked, but it may be the older specifications that give only the minimums.

 

[ishvaaag]

Maximum actual strength is important for overstrength checks where the full force of some structural item or part of Fu limit strength has to be taken assuredly by another.

Specifying a precise range may be also an indicator of the structural properties of the steel, mainly if allayed or ordinary structural. For seismic applications lower strength structural steels are known to behave with more ductility, and are sometimes selected or even mandated.

Respect the actual reason of the inclusion in the code with the precisions given, it must be, in my view, that are those for what the specifications are thought to be applicable.

 

[HgTX]

Further clarification--it's not "range" vs. "specific", it's "range" vs. "minimum".

Hg

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