two "k" values listed in3rd ed AISC manual?

[samdamon]

Gents, this is probably a dumb question but I don't understand why there are two "k" values listed in the steel tables for wide flanges in the 3rd AISC manual. One value is decimal and one is fractional, and they aren't equal. Can someone explain this? There must be a logical explanation. Which value should be used for detailing? Thanks

 

[SacreBleu]

This a "theory"- I am guessing that the fractional is for detailing purposes, and is the largest possible k dimension. The decimal is for computation of section properties, and is the "lower bound" dimension, since the k-dimension varies per manufacturer.

 

[Taro]

Correct. See this 2001 advisory from AISC...

http://www.aisc.org/PressRelease/DocumentDisplay.cfm?Document=Eng_advisory_tkandk1.pdf

 

[UcfSE]

Notice also that the radius where the flange meets the web is not a true circular radius so it will have a different dimension vertically or horizontally to the point of tangency with the web or flange. They will also vary slightly depending on the manufacturer I believe.

 

[samdamon]

Thanks for your replies. Taro, the link was useful.

A confession. Up to very recently I have been using the green book (ASD 9th ed) (Sacre bleu!) so when this change waa first made I was not aware of it.