truss base sizing help

[temper]

Hey all. So, I inherited 4 pieces of AL triangular truss (12" maybe?) about 8' long. Along with that I inherited 2 bases for standing the truss vertically. These are just a sheet of plywood, 4' in diameter, with a socket that the truss fits into. So, since I've never really worked with truss before, I thought I'd ask where I can find a table or chart about the recommended size of bases for truss (for a certain height) and how much weight should be added (if any). Is there a reference that describes this? Or, what's the proper way of sizing bases for vertical truss?

 

[bishopthomas]

There's no chart, just good old fashion common sense. Well, there's some science in there somewhere too. There are too many variables to make a chart. Wood/metal? What type of wood/metal? Construction? Size. Weight. Condition. If it's just plywood I'd be careful about putting anything on it. I built a pair of 36" square 3/4" birch bases. I put 1x4 around the bottom edges to elevate the base enough to get a bolt underneath (obviously, you want the bolt head on the bottom and the nut to come in from the top for the lowest profile possible).

 

[Les]

Gemini rents out 36" square metal base plates with their 12"x12" truss sticks as standard, so that may be a good place to start. They also recommend three sand bags per base assuming it's an 8' tower.

 

[techieman33]

It's going to depend on what your putting on it too. A couple of pars won't need much, and a big mover could require a big base with lots of weight.

 

[bishopthomas]

BML sells some pretty cool bases. They accept truss in various sizes and configurations as well as 1.5" pipe. I bought this one but they have other sizes as well. I plan on buying four of the 24" ones next month.

24" Base
30" Base
36" Base

Notice that they're all heavy duty metal (steel? iron?) bases and not plywood.

 

[temper]

Thanks for the replies. It seems to me that a 36" square base with about 100lb of weight total is about standard from everyone's responses. So, for once, something I inherited isn't going to need mods to make it safe! Hooray!

 

[David Ashton]

just a comment, indoors no problem, but outdoors with strong winds, big potential problem.

 

[temper]

Yes, this is for indoor use only. Good tip though.