

Ask HN: Why is the tallest manmade structure only 2,722 feet? - a3voices

I don&#x27;t get why nobody built a simple tower with a narrow base to best that. Is it really that hard to do, or that expensive? Why aren&#x27;t there any 10,000 foot towers?
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zachlipton
Elevators. I mean obviously there are significant structural concerns as well,
but elevators are a big part of what makes building super-tall buildings
uneconomic and impractical. The Elevator Conundrum, as Wikipedia dubs it
([https://en.wikipedia.org/wiki/Skyscraper_design_and_construc...](https://en.wikipedia.org/wiki/Skyscraper_design_and_construction#The_elevator_conundrum)),
means that as you build a taller building, you need more elevators to service
the floors. More elevators take up more space, meaning less rentable space for
occupants. While skylobbies, double-deck elevators, and other tricks can help,
they don't eliminate the problem, especially since no one is willing to
transfer elevators four times to get up/down. We also run into the issue of
how to build a 10,000 foot elevator, which is so far outside the competence of
manufacturers that it would represent a huge risk to the completion of the
entire building project.

I am, of course, assuming you plan to build a useful tall building instead of
an empty 10,000 foot tall shell for no particular reason.

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Pyrodogg
The elevator problem is partially solved by never leaving your section of the
mega tower!

Work on level 120 Sleep on 73 Recreation on 145 Skyway connections to
neighboring mega towers every 50-75 levels.

Actually travelling to the surface world would be akin to driving for hours
across the state. It's a trip and would be planned for accordingly, and happen
rarely.

~~~
27182818284
>Actually travelling to the surface world would be akin to driving for hours
across the state. It's a trip and would be planned for accordingly, and happen
rarely.

I must be missing something. 10,000ft is 1.8ish miles. That's like an 8 minute
bike ride not a cross-state drive. Even if it took 30 minutes by elevator,
that's a reasonable commute in cities like Chicago.

~~~
Pyrodogg
Yea, I went funny with the scale. Jumped straight from skycraper to something
the size of a GSV from the Culture series.

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brudgers
Ok, let's give your skyscraper a nice 80' x 200' floor plate. A 100 stories
up, and you've probably spent a billion dollars on construction and land and
entitlement...at least in the US. Less some other parts of the world, more in
others.

You're only half way to matching the tallest building, have just put an
additional million and a half feet of expensive space into the local real-
estate market, and your costs are only going up.

But that doesn't really paint the right picture about how expensive it is to
build upward beyond a half dozen stories or so rather than building outward or
just cramming more into less space.

No to put the cost of building upward in perspective: the great pyramid was
the tallest building for nearly 4000 years. Lincoln Cathedral was then the
tallest ever built for more than 500 [250 years if you want to say it lost the
title when the spire collapsed, which brings up the point that the great
pyramid would have been, but for erosion the tallest structure from 1647 to
1874, but was still the second tallest in the age of steam and iron].

So yeah, it's expensive and hard and unless you're the Pharaoh doesn't serve
much purpose.

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mikeevans
Relevant: [http://what-if.xkcd.com/94/](http://what-if.xkcd.com/94/)

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gus_massa
Some of the thecnical problems are discussed in "Billion-Story Building"
[https://what-if.xkcd.com/94/](https://what-if.xkcd.com/94/)

Another problem is the cost. Who is going to pay it? Do you want to pay it???

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VLM
Assuming you want a serious answer, a very HN one is to discuss scalability,
and unlike rope or cables or fiber, towers most certainly do NOT scale merely
linearly with length. Its way, way worse. Or if you prefer to think of it this
way, we don't have enough income inequality and/or world wide wealth for one
plot of land to "deserve" a 10 kilofoot tower.

Another fun term to google for is Euler and column buckling. That's why we
don't have 75000 foot tall radio towers, which at least superficially would
seem to be a great idea that could get past the scaling costs because
potential revenue would scale even better with surface area within line of
sight. Or even more interesting a 75 kilofoot rocket launching tower so you
could use higher Isp vacuum rated nozzles at launch (if you tried that at
ground level they'd buckle from the outside in)

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gdewilde
I suggest a giant snow man

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dekhn
ask yourself, why do you need a taller building, and if so, are you sure you
want to spend the money to engineer it?

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joeclark77
They say that the tall skyscrapers sway a lot with the wind. It's perfectly
safe, but it freaks people out. I've never been to the top of one to see for
myself.

