Skyscraper Heights

**LF22** · August 28th, 2003, 02:26 PM

Has anybody in this forum ever noticed how one skyscraper that is taller than other can sometimes be many stories shorter? An example of this would be the new Shanghai World Finance Center under construction and the old World Trade Center in New York. I have chosen to compare these two buildings im particular because they are both massive in scale and are inhabited to thier full structural height. The interesting thing is that while the Shanghai World Finance Center is taller at 1,614 feet compared to 1,368 for the WTC, the WTC actually contains more stories than the SWFC at 110 compared to 101 for the SWFC. If you divide the building's heights by their number of stories you will find that the average height per story in the WTC is roughly 12.5 feet while the average height per story in the SWFC is roughly 16 feet. This is a difference of 3.5 feet per story or roughly 20%. This may sound not like much but if both buildings were 110 stories you would find that the SWFC would be almost 400 feet higher than the WTC! Although minor height differences per story in skyscrapers are the norm, I don't get why the SWFC has 3.5 extra feet per story than the WTC. There seems to be a growing trend that modern skyscrapers have more height per story which seems to me like an awful waste of space. After all, doesn't logic dictate that the more stories you put in a building of equal size the more floor space you have therefore the building should be more economically viable? I don't know if I just have too much time on my hands or what but can someone please explain to me why different skyscrapers have vastly different heights-per-story.

Stumped

**Gulcrapek** · August 28th, 2003, 02:31 PM

It has to do with a number of things. I don't know all the reasons, but one is the increase in floor thickness for various ducts and newer systems. Also, by taking into account the total height of these two buildings it's not accounting for some mechanical space and nonfunctional structure above SWFC's skybridge etc. so the FTF height would be a little lower.

**LF22** · August 28th, 2003, 02:48 PM

Actually since the skybridge is on the 80th-90th floor that means that by logic the structure above must still be inhabited by floor space.

**Gulcrapek** · August 28th, 2003, 02:53 PM

I should have been more specific, I meant the hole containing the skybridge.

**Chicagoan** · August 28th, 2003, 09:49 PM

LF22 , you ask a good question, but the only reason why the issue is an issue is that you assume that naturally floor height MUST be similar. There is no such rule, all things being equal that is.

When Sears and the S- WTC were numbers 1 and 2 for WTB, both towers HAD 110 floors, but Sears was a full 100 feet (+/-) more.

Some apartment tower developers like to use a standard 8.5 feet and some like to go to a generous 10 feet. We could clab all buildings in cheap aluminum of shimmering glass, or warm brick.

Just accept it as just some of the diversity and variety that makes tall buildings and their construction wonderful.

**DominicanoNYC** · August 28th, 2003, 11:36 PM

Great answer Chicagoan. Also don't forget the spire factor. Some buildings (although I can tell when a spire is included in the height, but I thin k there was a thread on this subject) get a boost from the spire.

(Edited by DominicanoNYC at 11:39 pm on Aug. 28, 2003)