Truss Towers/goalpost structure

[lbird08]

Hi guys, I just wanted to run something by you.

 

I want to build a truss structure consisting of 3 upright truss 'towers' all connected by a horizontal section at the top. Each tower will be about 6.5m tall. The top, horizontal section will be attached to an existing fixed LX bar using right angle truss couplers. Outriggers will be used at the base of each tower and obviously base plates aswell.

Steels will also be run from each of the towers and the horizontal section to rawbolts in the back wall of the stage. (structural!)

I want to put 2 movers on each upright section - 1 mac 250E and 1 mac 500 on each.

The truss being used is Prolyte X30D triangular truss.

 

Does all of this sound ok?

 

Cheers!

 

Lawrence

[paulears]

On the face of it, it does look like you've taken sensible precautions. If the top sections are in essence a fixed truss, attached to a fixed bar which is strong enough, then you've just got the equivalent of a boom - just a stronger one. I don't pretend to be a mechanical engineer, but I'd consider using something like this, as long as I was certain the ground and the LX bar were suitable.

 

I'd also guess that somebody will pop up and say the usual "if you have to ask......." post, but here you are not using any truss specific method of assessment, simply fixing a vertical support to something above. You really have to look at what you have and decide if you think it's ok, and put your name to it. I don't think anyone here can really say yes or no without seeing the venue it's going into.

 

The confusion arises from the goalpost title. Freestanding goal post systems always generate concern, but that isn't really your query. Your is to do with the side mounted movers on a vertical support, which will try to move the top one way, or the bottom the other - these are your real issues once the strength of the support bar has been checked.