Joining Existing Angles

[Plainsboro]

I have two angles 3x3x3/8 x 12'-0" long with back to back separated 1-1/2". They are exisiting and horz leg is on top. There is a nut every 2" about 1/4 inch dia protruding in 1-1/2" gap b/w 2 L's ( so a restriction). I need to somehow join these angles. Shall I use a strap every 12" c/c? any better idea. one more thing , prefer accessibilty is from top but can be reached from below.(one reason to do it is that I can avoid single angle design, tough criterion given on page 5-309 AISC-ASD).

 

[Ron]

If there is a potential for reversal of load, you should provide gusset between angles, even with the nut restrictions. This will help prevent crippling under compression. Straps on top will work for the top "flange" of this "Tee" section, but won't do much to help the "web" if placed in compression or lateral load.

 

[Grizzman]

a few questions:
Why must you join the two angles?
how are the angles being utilized?
what are the bolts connecting to the angle?

why not calculate the maximum compression you need in the dbl angle, then calculate the max span each single angle can span to achieve the same allowable compression. that'll give you the frequency of connections required.
I agree that a gusset between the angles is a better connection, though you could go top and bottom with plates.