[TowerTalk] Assembled tower; lifting by Crane
w8ji at contesting.com
Wed Mar 16 05:56:21 EST 2005
> lift from a single point, without damaging the tower. Or
said another way,
> how long of a Rohn 25 tower can you lift, assembled:
> 1. from a mid point?
Not as much as around 2/3 up.
Think of it as a series of levers and fulrums. The largest
stress is at the first when you start to lift and it is all
nearly horizontal. When you grab at 2/3 (empty tower) you
have the upper 2/3 about balanced. The bottom of the bottom
1/3 is on the ground (With PVC pipe and caps over the open
so the pivot point of the crane and tower hanging at the top
counterweights the long section below reducing stress.
> 2. From one the top, with the base on the ground?
Well, I think the middle might sag a bit then. You can watch
it carefully as they lift and see.
I'm sure there is some limit to how much you can have on the
top at a given tower length.
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