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Comment by TravisCooper | Hacker News Reader

This is awesome. A lot of good comes from colocating office work into a central building so the outlying areas can be used for "life affirming" purposes.

Housing, parks, churches, restaurants, entertainment etc.

We should want more "lone wolf" office buildings like this in every city.

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They're rather expensive though, so you might be able to get more of what you like using the money differently.... instead of a single $750m 100-story tower in one block, build ten 10-story towers over 10* blocks, and you'd probably have $500m left over.

* Realistically, you could pack the equivalent square footage into less space than this, because you can build shorter buildings wider.

How do you figure this? One tower has less than 10x the elevators, less than 10x the footings, less than 10x the roof area, etc etc etc., vs 10 smaller buildings 1/10 the size. There are massive economies of scale to density.

Construction costs don't scale linearly with height, so I'd imagine the sweet spot of cost per square foot is a mid-rise building. But I admit I don't have the hard figures on hand.

You might need more elevator banks per floor, though - a high capacity office building usually has more worries about routing the elevators and might have extra banks on middle floors that you switch to, etc

I would definitely expect the elevator set up to be complex in a 90 floor building.

A single skyscraper with 10x the floors needs more than 10x the structural mass to stay up, involves far more complexity and they're actually notoriously inefficient for elevators and stairs (you need to provide 100 stories of just enough capacity to service your top 10 floors, not 10 stories, and end up with potentially 30 to 40% of your overall floor area as a service core)

The economy of scale comes from using up less high value land; everything else costs more

Sometimes skyscrapers have split elevators with lobbies at higher floors. To get to the very top you disembark half way up and then the capacity of these upper elevators can be less.

Actually, tall towers have many more elevators. Usually a set of express and local elevators, because someone on the top floor should not have a ten minute journey on an elevator making all stops.

It’s why tall buildings taper as they get taller, to minimize the amount of people transported to higher floors.

Physics probably has more to with the tapering than number of people transported

number of people transported dictates how many elevator shafts are needed, and express elevators to the top mean less leaseable space on lower floors. so less people at the top means more leaseable space.

there is a lot of work going into optimizing elevators so that as few shafts can be built as possible while keeping wait times to a minimum.

That's an understandable and interesting challenge

I can't think of a good way to say this, apologies if it comes across poorly.

I commented because it felt like cause and effect are backwards

Like, I'd easily believe it's more due to stability than being able to say "aw shucks, we wanted to put elevators there but we can't fit them"

It's like saying the skyscraper has an upside down pyramid to create a choke point. Just do that, don't fight physics too.

People don't go to floors just to fill the space, but the space kind of informs it. It's circular, as I ramble I understand better

Developers are in the business of renting out space, so anything that reduces rentable space is bad for business.

It's also why tall towers only get financed during times of easy credit; they don't make much financial sense otherwise. Most supertall buildings take many years to reach full occupancy, if they ever do at all; it is why the World Trade Center complex has not been fully completed to this date.

Have many architect friends. More stories (especially at common break points of >1, >10) means much more complicated design for elevators, emergency regulations, design against elements etc.

My assumption is like the other replies, taller is expensiver, but apparently sometimes there is a sweet spot for more height in one building, eg browsing around Wikipedia as a result of OP, the tallest building in Tulsa Oklahoma:

https://en.wikipedia.org/wiki/BOK_Tower

> BOK Tower was built for the Williams Companies, whose CEO at the time, John Williams, was impressed by the Twin Towers and originally wanted to build two 25-story replicas in Tulsa. However, prior to construction, Williams was informed that having two separate towers would require more elevators than a single, larger tower.[citation needed] The plan for a quarter scale replica was then changed to a single 52-story tower, double the height of the two planned towers.

Hopefully someone fills in a citation!

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