Edge Angle Drag Members

[theshearstud]

If you are trying to squeeze out all of the capacity of an edge angle drag member that is spanning perpendicular to steel joists, do any of you think it is defensible to use a K=0.5 when calculating compression buckling capacity of the edge angle? Thanks

 

[KootK]

It's dubious and would depend on your connections and the buckling mode under consideration. Even then, we usually take theoretically fixed to mean about k=0.65 in practice. New build or existing?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Guastavino]

If it's on block wall can you use the bond beam? Or if it's on a steel beam can you use the girder?

 

[mike20793]

Can the joist seats take the shear to the frame/wall below? The 2 1/2" seats don't have much capacity in them and it gets much lower as the seat height increases, so we usually just provide an angle/tube between the joist seats.

 

[theshearstud]

It's new construction. Drawings already went out. Luckily this is only at one spot. I guess the best thing to do would be just to put a piece of tube at a couple of spots to chop that unbraced length like mike said. Njlutzwe- its spanning the joist seats so we can't count on the beam.

Back to using the joist seat to transfer load to the beam, I have constantly been told that Vulcraft does not allow it, but they have published examples in their Design Guide. Does anybody know the reason for this? Is it a true statement that joist seats CANNOT be used?

 

[KootK]

Vulcraft has done it for me in the past to the tune of about 2500 #/seat max for a 2.5" seat. I could see why they wouldn't want to do it. The mechanics are pretty sketchy, particularly if your collector angle is significantly offset in plan from your intended drag strut below.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[theshearstud]

Thanks for all the input fellas.