Skyscrapers
-
https://www.worksinprogress.co/issue/why-skyscrapers-are-so-short/
The economic height of buildings is lower than what’s physically capable of being built, and once that economic height rises high enough we will start to see legal restrictions spring up that further limit building height.
Read on to learn about load-bearing, sway prevention, and why buildings don't go much higher.
One major limit is elevators. A tall building requires speedy elevator service to make the upper floors usable, as long elevator waits reduce the rent that can be charged. Like with other conveyance technology, elevator system size is governed by traffic at peak loading times, generally at noon for an office building. As a building gets taller, more and more elevators are needed to service the upper floors, which intrude on the floors below. The result is that a taller building must devote proportionally more and more of its space to elevators. There are ways to squeeze more capacity out of a smaller number of elevator shafts (such as by using double-decker elevators, or transfer floors at higher levels), but they don’t alter the fundamental dynamic. Residential buildings, which have fewer occupants per unit area and lower peak traffic volume, have it somewhat easier here.
Everything in a tall building faces a similar sort of dynamic. Building taller requires more complex mechanical and plumbing systems, due to the higher water pressure and the complexities of handling outside air (which may, for instance, be moving at a high speed). It requires larger and more expensive lateral resisting systems and foundations. While the building is under construction, it takes more time to move workers and materials to the upper floors, resulting in higher construction costs. This all combines to make construction more and more expensive as the building gets taller.
