Engineering question

Is there a physical limit to the height of a building? How tall could a building be until it becomes structurely unsound?

i cant remember the specs but this question was a factor in the attempts to build a ladder to space so we could send satellites out that way.

The article i read was in either discover or popular science, it said something like wood only goes 800ft and steel only goes 3000 feet, so they’d have to use carbon nanotubes. That 800 & 3000ft are just guestimates from what i remember though.

There are a few answers to this question, but from what I understand (as a mechanical engineer and not civil) is that there is no real physical limit. To each structrual problem there would be a coresponding structural answer. The most obvious problem is that has you add more levels, each bears down on the ones below it. But that can be accounted for by adjusting the size of the base (like a pyramid). Then there is the problem of wind, earthquakes, and soil density.

As a mechanical engineering I know there are three huge problems: 1.) elevators 2.) low atmospheric pressure and 3.) water pressure.

There is a physical limit to how high cable elevators can go because the cables start to oscilate. This can be overcome by having “stages” of elevators, but its unlikely that people would want to switch elevators several times on their way to the top. Its then going to take a really long time to get up there which again people don’t like. Imagine comuting for an hour and then commuting for another 30min on the elevator, standing up…

The other problem was that has you get higher the pressure gets lower so you have to seal and pressurize the building. This means that you can’t open windows, and people don’t like that. Because the building is sealed you have to very extensively control the air that flows in and out of the building. (don’t forget its cold up there…)

It also takes a huge amount of power to pump water up that high, so its unlikely that you’d want a shower on the 253rd floor.

Another problem (as evident during 9/11) is that I believe the highest ladder the fire department has reaches to the 15th floor, correct me if I’m wrong. It becomes very difficult to evacuate people from floors above that.

So to conclude, the Discovery Channel type answer is “no, engineers can find a way to build as tall a building as you can afford. But its unlikely anyone would want to work/live up that high.”

Hopefully a civil/structrual engineer will be along soon.

This is a very random recollection from some book/magazine I read…so take it for what it’s worth:

But ISTR a fact that the compressive forces at the base of a building would create enough heat to rise above the melting temperature of any known material by the time the building reached 1/100 the radius of the earth.

But that’s about 40 miles tall, or 160 times taller than anything we’ve built so far.