[khris]

Is it possible for skyscrapers to be built without any mechanicals on the top of the building? See this for example:
http://www.worldarchitecturenews.com/index.php?fuseaction=wanappln.projectview&upload_id=23698

I realize that's a rendering, and it might not end up looking like that, but I don't see any room left for mechanicals on the roof or below the roof. Where else could they put the HVAC, etc?

 

[dt_toronto_geek]

Perhaps it's cleverly hidden behind the glass folds?

 

[officedweller]

Sure -
case in point - the Swiss Re: Building 30 St. Mary Axe:

http://www.30stmaryaxe.com/photo_top.html

 

[jahvon09]

The Willis Tower, as far as I know, has no rooftop mechanical equipment.

All I see are the 2 or 3 tall antenna atop the building.

Well, the only thing up there are the window washing scalfolds that work like an elevator.

 

[ChesterCopperpot]

Whlist not on the roof - there are a few mechanical floors at the top of the Willis Tower

 

[NorthWill]

Yes.

Mechanical and electronics equipment uses up valuable floor area (just like elevator shafts), so while planned to allow for sufficient redundancy in the services they provide, a buildings mechanical and electronics equipment is situated in a way that minimizes the number of mechanical floors and mechanical floor area.

Though the percentage may vary widely, depending on structural, mechanical, and aesthetic concerns, a typical rule of thumb would be that a skyscraper requires a mechanical floor for every 10 tenant floors (10% space allocation).

In some buildings they are spread evenly, in others they are clustered to divide the building into segments, whereas in many others they are mostly concentrated at the top.