That is the general rule for towers built with the typical cast in place or steel framed construction, but these days there are new cheaper ways to build 10 story buildings. Recently there are prefab/modular construction methods being used that allow builders to build up to and over 10 stories relatively cheaply. The new tower at
Whittier choice is 10 stories and it was built with 8 stories of prefab modules stacked on top of each other above 2 concrete floors and a concrete core.
Heres an article on modular construction for mid-high rise structures.
https://www.base-4.com/modular-p4-steel-unit/
For the above building in this thread “the caldwell”
34 munroe st. there arent many construction pics I can find but it appears to be using prefabricated light weight framing built on top of a single concrete base floor.
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Dellbrook
Heres a couple articles talking about this type of construction.
https://buildsteel.org/prefabrication/chicago-project-with-tight-laydown-area-goes-steel/
https://www.directorsteelstructure....teel-structure-buildings-and-other-buildings/
“Cost reduction and rapid construction are the two main advantages of prefabricated steel structures.”
These methods are pretty new in north America, but theyre picking up steam and should help a lot with buildings that fall into that grey zone where they used to be too expensive for the height.