Limiting Width-Thickenss Ratios

[ToadJones]

Anyone know the reason why certain cross sectional elements have no compact criteria.

 

[MiketheEngineer]

Cause they have low torsional stability. They roll over and die!!

 

[ToadJones]

They should consider adding that to the commentary

 

[nutte]

What cross sectional elements are you looking for?

 

[JoshPlumSE]

Mike -

Do you have a reference for this? I'm just interested in looking up additional information.

 

[ToadJones]

nutte-
I do a lot of analysis of existing structures some of which are old.
I run into built up shapes fairly often that dont fit the cookbook of table B.4 (or whatever it is).

Today I was dealing with a plate girder built up from a single web plate with angles for flanges---essentially making a giant channel and it also had a longitudinal channel with the flange of the angle welded to the web of the built up shape 1/4 of the depth from the top.
You can see where there is a lot of width-thickness ratios to check.

I have always thought the tables were poorly explained. AISC 360-05 is much better than the Green Book but I still think the commentary is lacking.

Josh-
I too was after some more literature