Takedown of overhead bridge cranes

Overhead bridge cranes, at auctions, sell either for outrageous money, or for next to nothing. The reason is that, while expensive to order
and install, they are difficult to take down and built to suit a particular building. So, unless there is an auction bidder who needs this crane, there is no one to bid on them.
And here comes my thinking, I want to be able to bid on them and and remove, economically and safely, for scrap metal.
I am talking about the "big ones", say 30 ton capacity and 60 feet sapan, not little ones.
The $64,000 question is how to take them down.
I have a 30,000 lbs capacity forklift and a 11 foot boom for it, that can be raised by forklift to about 11 feet, giving me about 22 feet of vertical reach. I also have a number of smaller forklifts like 15,000, 18,000 etc.
What do you think, can I take down biggish cranes with it, if they are say at the height of 20 feet?
I am not stupid and I can think of various possibilities and attachments, however I also see that things can go very wrong at such great heights and leverages.
Anyone seen this done?
Maybe add outriggers to the forklift?
i
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Another option besides Gunner's is to rig 'keeper' tackle on both ends, to the masts, before you start trying to fork the beam down. With adequate strength of cable and some 'snubbers' to cushion a short fall, you could fork down in increments, adjusting the rigging each time you want to go lower.
LLoyd
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Ignoramus3507 wrote:

Three forklifts makes it sort of easy. Position one forklift mid span, and two on either side of it some reasonable distance away. Make sure all three are adequately supporting the load, then torch/plasma cut out the middle section and remove. Move the mid forklift over to one side to support the span from the track and cut the section that the other forklift is supporting loose. Repeat as necessary. If you throw four or five people at this you should be able to play musical forklifts and have the whole thing down safely in an hour or less.
A lot of resources at it, but not a lot of time, so you need to do the math to see if it makes sense. Obviously for lighter spans you could support with two forklifts near the ends, chain the ends to the tracks and cut out and lower the entire span in one shot, then just grab the ends with the forklifts, unchain and lower. Either way, you have enough equipment to attack the project with overwhelming force and just get it done quickly.
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Hey Iggy,
I don't recall seeing an overhead crane removed, but I've seen 5 that I can recall being installed. Each of those was done with a crane on the ground outside the building lifting the cross-beam from the floor of the building through a 4' X 4' access cut in the roof for the purpose. The beam is most often (still) on a semi-trailer, so there is no need to have it off-loaded beforehand. After installation is complete, the access hole is then made into a sky-light.
Take care
Brian Lawson. XXXXXXXXXXXXXXX
On Sat, 01 Nov 2014 18:18:27 -0500, Ignoramus3507

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