stainless steel bolt FoS

[NS4U]

I've read this document (

http://www.ssina.com/download_a_file/fasteners.pdf)

it indicates that a 1974 stainless steel design manual by AISI used a FoS=3 to calculate SS bolt allowable strength. Now, I also read AISC DG 27 (Structural Stainless steel design), which uses a FoS=2 to calculate SS bolt allowable strength. Both documents calculate the nominal (unfactored) bolt strength essentially the same, the only significant difference is that they use a different FoS.

It seems like there was a shift from a FoS=3 to FoS=2 over the last 40 years. Anyone have any background info? FoS=3 seems high. Are the codes today more informed, thus justifying a lower FoS?

 

[SlideRuleEra]

Design Guide 27, what page?

In the SSINA document, found the reference on Page 9.

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[NS4U]

pg 49 of DG 27. Omega=2.0

Sorry- should have given page numbers!

 

[mike20793]

The appendix typically justifies the values of strength reduction factors and factors of safety for each mode of failure. It is consistent with testing and AISC 360.

 

[SlideRuleEra]

NS4U - The answer is probably related to the meaning of "ASD"...

In 1974, calculation would have been performed using ASD. It meant "Allowable Stress Design". Even LRFD was not introduced until 1986.

In 2013 (DG 27), it means "Allowable Strength Design"

They are not the same.

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