Beam Bearing Stiffeners for 2010 AISC Section J10

[vincentpa]

Does anyone have a design methodology or can anyone point me to a design guide for the design of partial-depth web and flange stiffeners according to the 2010 Edition of the AISC Steel Code section J10? I cannot find any guidance on how to design these elements anywhere. The description of the procedure for full-depth stiffeners is spelled out clearly in the code. The only item I would need to clarify for full-depth stiffeners is the force used to design stiffener to web weld.

 

[TheMoonlitKnight]

Did you try this thread?: [URL unfurl="true"]http://www.eng-tips.com/viewthread.cfm?qid=271480[/url]

 

[vincentpa]

Yes I did. Thanks. But, what I don't necessarily agree with is designing the plate to resist bending without considering the contribution of the flange. The plate and the flange will act like a T section. I found an example somewhat similar to this in Blodgett on page 3.3-25 and 3.3-26. The example is of a stiffened base plate. I was hoping AISC would have a methodology since they address stiffeners in the code. Maybe I'll have to wait until the next time AISC remakes their code for them to provide an example.

 

[vincentpa]

Plus, AISC specifically tells the engineer to what forces to design the well to the flanges and the webs. Neither of those forces address bending.

 

[JoshPlumSE]

What's the load path. The load comes in from above the beam and gets into the flanges, then it gets into the stiffeners.... If you don't carry the load to the other side with a full depth stiffener, then you have to design that stiffener so that it can transfer that full load into the beam web. After all, you can't just assume the load disappears after it gets into the stiffener.

I believe AISC Design Guide 13 (which is really meant more for moment connections designed to LRFD 2nd edition) addresses partial depth stiffeners like this.

 

[dhengr]

Vincentpa:
As Josh suggests, the whole idea of those stiffeners is to get that concentrated load into the web. They may, but don’t have to run all the way to the other flange. Of course, their loading must be reasonably balanced or they will tend to punch through the web at their middle termination, and that would be a reason for running them (or a single stiffener) to the opposite flange. The welds are checked for bearing at the flg./stiff. joint, and for shear flow over their height vs. your loading at the web/stiff. joint. Reread Blodgett, he doesn’t suggest ignoring combined stress and the potential of a bending component, but explains why it can usually be played down. Taller stiffeners will reduce this bending component, as will running the stiff. to the opp. flg. Also, consider, most of the load is transferred in bearing immediately around the beam web/flg. fillet and near this region in bearing on the flg./stiff. welds, at fairly favorable lever arms, not out at the tip of the stiff.