how skyscrapers, arenas and stadiums are safely built when they are so high up that machinery can’t reach the top
In: Engineering
Unless I was taught wrong they build using a crane. Then remove the cross section of the crane and use the vertical portion as the elevator shaft. (Skyscrapers) Having watched them build Miller Park (Now American Family Field baseball stadium Milwaukee) I can verify that they have mobile cranes that are actually big/tall enough to build stadiums and arenas. It is VERY dangerous, however, as was proven when wind caused the partial collapse of the roof while they were building Miller Park, killing 3 construction workers.
They use cranes which can be placed on the part of the building that’s been built so far. The machine itself can’t get as tall as the building, but put the machine on top of what you already have and the CABLE can still reach the ground.
They also use something called [slip forming.](https://en.wikipedia.org/wiki/Slip_forming) The concrete form for the building is constantly moving upwards. Fresh concrete gets poured up top, hard cured concrete comes the bottom. The forms moves up by jacks secured to the hardened concrete.
[https://www.youtube.com/watch?v=XEAc11FHzpY](https://www.youtube.com/watch?v=XEAc11FHzpY)
[https://www.youtube.com/watch?v=rIMxXsyzzM8](https://www.youtube.com/watch?v=rIMxXsyzzM8)
Cranes can then be attached to the top, like others have mentioned, to haul up all the other stuff like cladding and mechanical equipment.
There is an entire engineering branch that design how to do it. The hardest are bridges. 90% of a bridge design is how to put it there.
Skyscrapers are pretty easy in comparison, you build 10 floors, than put a crane on the 10th floor and make another 10 floors, until you get to the top. Stadiums are even easier, except for the roof, stadium cover is as complex as a bridge to be put in place.
[Self-climbing cranes](https://youtu.be/oSyC8pxJdeQ ). We’ve got one on my site and it blows me away every time it jacks itself up.
The video is long but informative.
They use what’s called tower cranes. https://youtu.be/oSyC8pxJdeQ. pretty interesting video on how the tower crane gets built higher as construction continues. They can get built crazy high
In the case of some radio towers, they’re often built from the top down. Build the top, then keep building the body beneath it, stacking the pieces as you go.
Because the lower levels are build to withstand the weight of the higher ones, therefore they can also fit the machinery required to work on it. Cranes do a lot of the heavy lifting, and then other specialized machines are lifted to where they’re needed
There is an interesting documentary on building The Shard in London where novel methods were employed.
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