From: Ron Kean <firstname.lastname@example.org>
>The tallest buildings use steel for structural strength. The
>tallest non-guyed buildings are the twin Petronas Towers in Kuala
>Lumpur, 1455 feet, I think. They are office buildings, possibly
>with some residential units. They are right next to each other
>and are connected by a catwalk about halfway up. The tallest
>guyed towers are for TV transmitting antennas and are as high as
>about 1400 to 2000 feet. I think the tallest one was in Poland,
>but it fell sometime in the 1980s.
The Petronas towers are a joke, an 80 something story building with a twenty story spike on top, the fact is from the observation deck of the Sears tower you look down on the Petronas towers. The clowns that decide all this had to change the criteria as to what made a building the tallest, they came up with 5 requirements. The Petronas Towers got one, the World trade center got one, and the Sears tower got three.
>All else being equal, for a non-guyed structure, a tapered design,
>like the Transamerica building in San Francisco, should allow for
>greater height. A practical problem with very tall
>office/residential buildings is that the overhead associated with
>servicing the upper floors takes up so much space on the lower
>floors, and costs so much, that the building becomes uneconomical.
>Many elevators must be provided, for example, to service a very
>tall building, as the occupants would not want to wait 40 minutes
>every time they want to take an elevator. The infrastructure of
>emergency stairs, water supply, fire protection, sewage service,
>electrical and communications cables, heating, air conditioning,
>ventilation, and maintenance service elevators takes up a lot of
>space. Water pumps, pressure tanks, electrical transformers, and
>emergency systems are needed throughout much of the building. It
>becomes overwhelming and the building chokes on its own
The Sears tower solved the elevator problem by having three elevators in each shaft, you have to transfer about every 33 floors, only a few elevators go all the way. Trivia question: How many elevators does the Sears tower have? Answer: same as the number of floors, 110.
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