How do they get cranes off HUGE buildings when they are finished building them.?

Question

I have always wondered how they get cranes off the top of huge buildings when they finish building them.

I have had many people tell me how they THINK the cranes are taken off. But I want to know for sure. Can anyone give me some evidence? A web site or something??

When I say big building I mean like 100 storeys.

I have been told things ranging from

"a helicopter takes them off"

To

"They build tracks down the side of the building and drive it down"

And

"They pull it to pieces and take it down the elevator".

These MAY be real but sound like wild guesses to me.

So does anyone know the answer?

Answer 1

http://science.howstuffworks.com/tower-crane4.htm the link says it all...a typical tower crane grows as the structure grows...it has an internal self lift system that "jacks" the main section to allow for subsequent sections to be added...

I have seen helicopters raise and lower sections but never have I seen a set of tracks or elevator used...not to say that it isn't possible but I have only worked big buildings in NYC...maybe things are done differently elsewhere in the world

Answer 2

1

Answer 3

Large "hammer-head" cranes are usually jacked-up or winched-up a section at
a time as the building rises. The jacking/winching is usually done near the
top where there is a telescoping section. Jack/winch it up one story which
temporarily lengthens the telescoping section, hoist and bolt new support
steel in place, and you're set to go. Reverse the process for disassembly.

See www.towercrane.com.