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Design Guide 13 Errata

Design Guide 13 Errata

(OP)
The Errata for Design Guide 13 list a correction for page 9 that I would like to ask about.

The original text shows two equations for "alpha sub" one for a four bolt extended end plate and one for an eight bolt extended end plate.
The Errata seems to say that the two equations should be replaced with one equation that is the same as the four bolt pattern equation.
Is this correct, if so is the difference for the two configurations taken into account in the "b sub s" term?

thanks

David

RE: Design Guide 13 Errata

I believe you mean 'alpha sub m", correct?

Design guide 13 is now a bit dated now (published in 199) I'd look at the 2nd edition of Design Guide 4 (published in 2003) for a more up to date column flange bending equations based on yield line theory for the column flange. This newer criteria has different formulas for stiffened vs unstiffened flanges and for 4 vs 8 bolt end plate connections.

RE: Design Guide 13 Errata

(OP)
Thank you for the response.
I actually had moved to using Design Guide 4 instead, so I am glad to see that is the preferred guide.
If you would indulge me I do have a question about the procedure.

On the column side, in using the flange thickness required calculation I have determined that I need stiffeners (8ES) at the flange.
The flange thickness of my column is good only if I use the Yc of the stiffened flange.
You are then shown to find the flange flexural strength, and subtract from that the minimum of the 5 or 6 limit state strengths that follow in order to find the required stiffener strength.
However none of my limit states are less than the flange flexural strength.
This leaves me with a negative number when the limit state strength is subtracted from the flexural strength (R sub ust).

I believe this is because the flange thickness requirements are based on the moment based on the bolt capacity and the subsequent calculations are based on the actual moment.
Do I just pick a stiffener thickness close to the flange thickness and call it good?

Thank you

RE: Design Guide 13 Errata

There are two column flange bending strengths that you calculated.... the UN-Stiffened strength and the stiffened strength.

If you use the Un-stiffened strength for Phi*Rn in equation 3.32 then you should have a positive requirement for the required stiffener strength.

Essentially, the stiffener must be designed for the difference in strength between the unstiffened strength of the column and the demand strength of the loading.

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