# What is the practical limit on tall buildings? **URL:** \ **Category:** Factual Questions\ **Created:** [April 19, 2014, 2:12pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485 "2014-04-19T14:12:13Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![SirRay](https://avatars.discourse-cdn.com/v4/letter/s/cc9497/32.png) [@SirRay](https://boards.straightdope.com/u/SirRay)\ **Post date:** [April 22, 2014, 4:58pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/41 "2014-04-22T16:58:39Z")
> [@Incubus](#): > > I’ve also heard that the wind hitting the tower will cause it to sway slightly. On higher floors this sway is more significant, so you would get people on upper floors getting “seasick” from the slight motion. [Tuned Mass Damping is your friend](http://en.wikipedia.org/wiki/Tuned_mass_damper#Dampers_in_buildings_and_related_structures) to reduce wind swaying in tall buildings. > [@msmith537](#): > > Whenever someone advocates these self-contained multi-use “archologies”, I don’t think of utopias. [I think of the Sim City 2000 arcologies](http://simcity.wikia.com/wiki/Arcologies), which would launch if you reached a certain level: > [@](#): > > The Launch arco trick can be done in the Windows version of Sim City 2000. After building 450 launch arcos, a message will appear saying: “The exodus has begun” and the arcos will explode and show another message: “Your launch arcos have departed into space to find new worlds. You have been compensated for the construction.” ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [April 22, 2014, 5:20pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/42 "2014-04-22T17:20:32Z")
> [@Really\_Not\_All\_That\_Bright](#): > > I still think plumbing is going to be an issue. What issue are you thinking of? We already have to pump water up to supply anything higher than a few stories. [The Willis Tower has pumps in the basement, 31st floor, 64th floor, and 88th floor.](http://www.straightdope.com/columns/read/224/when-a-toilet-atop-the-sears-tower-is-flushed-do-the-contents-fall-110-floors) Want to go higher? Add another pump every 20-30 stories or so until you reach the top of your arbitrarily high building. Likewise, the drain problem has already been solved, too (see link). ---
**Author:** ![Cartooniverse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cartooniverse/32/3084_2.png) [@Cartooniverse](https://boards.straightdope.com/u/Cartooniverse)\ **Post date:** [April 22, 2014, 5:26pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/43 "2014-04-22T17:26:12Z")
> [@Wesley\_Clark](#): > > Another issue is the elevators. People will have to use multiple elevators, and it will take several minutes to get to where you want to go. Not meaning to be a wise-ass at all with this statement: Perception is reality. I clearly remember several visits to the World Trade Centers in NYC. A few tourist visits to the Observation Deck, a few working trips using the series of freight elevators to move gear up to Windows On The World restaurant. The express elevators that ferried people to Windows On The World [took 58 seconds for the trip](http://www.nytimes.com/2001/09/19/dining/windows-that-rose-so-close-to-the-sun.html). > [@](#): > > Within a year of opening, in April 1976, Windows on the World was one of the most talked-about restaurants in New York, and a prime draw for tourists, who lined up to take the 58-second elevator ride to the 107th floor. It always seemed a very long elevator ride- and yet in the context of very tall buildings, a single-shot 58-second ride really is not so long. A bit tough on the inner ear, if you know what I mean. Taking the freight elevators was brutal. One had to give the better part of a day to drive into the underground loading docks complex, download, check in with normal building security, roll down the dock to the hallway to the Freight Elevators. Then wait your turn. And wait and wait and wait and wait and wait and wait. It was stunning how long it took. ( Yes, there were quite a few Freight Elevator cars, not just one. Cannot remember how man. 4? 6? ). And I do seem to remember that they - unlike the Windows On The World trip- were staggered. No way to do a straight shot ride up to the top in those. ---
**Author:** ![Cartooniverse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cartooniverse/32/3084_2.png) [@Cartooniverse](https://boards.straightdope.com/u/Cartooniverse)\ **Post date:** [April 22, 2014, 5:33pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/44 "2014-04-22T17:33:15Z")
[The article discussing the methods employed to reduce sway](http://en.wikipedia.org/wiki/World_Trade_Center) > [@](#): > > The World Trade Center towers used high-strength, load-bearing perimeter steel columns called Vierendeel trusses that were spaced closely together to form a strong, rigid wall structure, supporting virtually all lateral loads such as wind loads, and sharing the gravity load with the core columns. [2-Plane Vierendeel Truss](http://www.transportscotland.gov.uk/files/documents/reports/j10568c/j10568c-g06.jpg) ---
**Author:** ![fiddlesticks](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fiddlesticks/32/18129_2.png) [@fiddlesticks](https://boards.straightdope.com/u/fiddlesticks)\ **Post date:** [April 22, 2014, 5:36pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/45 "2014-04-22T17:36:40Z")
I remember reading that the swaying in the Burj Khalifa’s upper floors have a pretty serious “seasickness” effect, so no doubt the Saudi building will be even worse in that regard. However, I also remember that the “Life After People” series showed the Burj surviving 250 years before collapsing from corrosion effects (after losing its glass windows early on), so it’s a pretty stable structure. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [April 22, 2014, 7:49pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/46 "2014-04-22T19:49:38Z")
> [@Lumpy](#): > > If you can build a space elevator at all, it’s possible; but I’m not sure what the point would be. From a structural point of view you would be hanging dead weight on the end of the tether that would have to be supported by the rest of the structure. Dani Eder (formerly of Boeing) has expressed the opinion that a tall tower built upwards would be a useful accessory to a space elevator. The elevator hangs down from orbit to meet the top of a 50km tower, which supports its own weight, and can presumably withstand the effects of the Earth’s atmosphere better than a thin tape under tension. See [http://yarchive.net/space/exotic/tower\_launch.html](http://yarchive.net/space/exotic/tower_launch.html) ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [April 22, 2014, 10:01pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/47 "2014-04-22T22:01:33Z")
I didn’t go through the entire discussion thoroughly, but my gist of it was that it was a minimal weight construct to try to lift launch elements above the atmosphere, not the extra sheer dead weight that a living building full of people would engender. And Geoff Landis got one thing wrong that’s pertinent here: Wright did not “design” a mile high building in the 1930s. At best, [he sketched one in 1956](http://www.wbez.org/blog/john-r-schmidt/2011-08-25/frank-lloyd-wrights-mile-high-building-90793). Nobody today seriously believes it could have been built then, and Wright never provided enough information for us to know if it could be built today. BTW, he was 89 at the time. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [April 23, 2014, 2:06am UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/48 "2014-04-23T02:06:50Z")
Here’s a paper by Geoff Landis on the subject of tall buildings; > **[20030022661.pdf](https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20030022661.pdf)** > > 74.53 KB another science fiction author, Neal Stevenson, has also produced some theoretical work on tall towers, see [http://www.fastcodesign.com/3018510/straight-out-of-sci-fi-cyberpunk-author-plans-tallest-skyscraper-ever](http://www.fastcodesign.com/3018510/straight-out-of-sci-fi-cyberpunk-author-plans-tallest-skyscraper-ever) he and his collaborator seem to think that the problem of wind will be significant, despite designing the structure as an open lattice. ---
**Author:** ![Mr\_Downtown](https://avatars.discourse-cdn.com/v4/letter/m/8e8cbc/32.png) [@Mr\_Downtown](https://boards.straightdope.com/u/Mr_Downtown)\ **Post date:** [April 23, 2014, 3:35am UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/49 "2014-04-23T03:35:08Z")
As a Chicago tour guide, the subject of sway (structural drift) has interested me for several years. I can find standards that specify how much drift is permissible, but no one ever tells what the period of oscillation is. I would have thought the period would be 30 to 60 seconds, yet people always tell stories of sloshing in the toilet bowls. Has anyone in this discussion ever witnessed that _personally?_ ---
**Author:** ![Little\_Pig](https://avatars.discourse-cdn.com/v4/letter/l/c57346/32.png) [@Little\_Pig](https://boards.straightdope.com/u/Little_Pig)\ **Post date:** [April 23, 2014, 4:03am UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/50 "2014-04-23T04:03:19Z")
[In a mile high tower](http://vimeo.com/4937909) not all users of the building would be going to the top. Make the top third condos and shopping/services for residents. Regarding elevators - [The John Hancock Center does boast the world’s fastest elevator, flying you up 1,000 feet to the 94th floor observatory in a thrilling 40 seconds!](http://www.smartdestinations.com/chicago-attractions-and-tours/360-chicago/_attr_Chi_Att_360_Chicago_John_Hancock_Tower.html) (Its not all that thrilling coming down after a night at the 95th floor bar.) Pizza delivery mightl be a bitch. On the other hand, I am not an architect. Nor do I deliver pizzas. ---
**Author:** ![Siam\_Sam](https://avatars.discourse-cdn.com/v4/letter/s/d78d45/32.png) [@Siam\_Sam](https://boards.straightdope.com/u/Siam_Sam)\ **Post date:** [April 23, 2014, 4:34am UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/51 "2014-04-23T04:34:48Z")
> [@Diceman](#): > > Something that hasn’t been mentioned yet: where is the food for all of these people going to come from? Soylent Green. ---
**Author:** ![TroutMan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/troutman/32/6721_2.png) [@TroutMan](https://boards.straightdope.com/u/TroutMan)\ **Post date:** [April 29, 2014, 9:57pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/52 "2014-04-29T21:57:46Z")
Randall Monroe tackled this question today in his [What If](http://what-if.xkcd.com/94/) series. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [April 29, 2014, 11:21pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/53 "2014-04-29T23:21:51Z")
Not only did he apparently steal that from us, we did a much better job at answering the question. 🆒 ---
**Author:** ![SpyOne](https://avatars.discourse-cdn.com/v4/letter/s/82dd89/32.png) [@SpyOne](https://boards.straightdope.com/u/SpyOne)\ **Post date:** [April 30, 2014, 2:35pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/54 "2014-04-30T14:35:34Z")
> [@buddha\_david](#): > > The limiting factor in building supertall skyscrapers is providing enough space for elevators to move people around. We could conceivably construct a building five kilometers tall, but the logistics of transporting people between the top and bottom floors in any reasonable timeframe would be a significant challenge. This was true when the Empire State Building was built. I have heard experts say that if the Empire State Building had the proper number of elevators to serve its office space, the entire first floor would be nothing but elevators. But this problem was solved by the time they built the Sears Tower: multiple elevators in the same shaft. So in one shaft there will be an elevator serving floors 1-9, then above it one that serves 10-19, then above that one that serves 20-29 and so on. Then there are express elevators from 1 to 10 or 20. People would need to change elevators two times to reach their floor (three, for _really_ tall buildings), but each ride would be pretty short, with the last one being the longest (although some folks on the 15th floor might prefer to take the express to 20, walk down one flight, then catch an empty elevator down from 19). The big limit on elevators seems to be this: if they accelerate (or decelerate) faster than 1/10g, that will cause some people to vomit. Sears Tower found this out, and had to slow their elevators down. The elevator problem got solved decades ago. The limits today are: 1. strength of building materials. The higher you build, the more weight is trying to crush the bottom floors (or the support columns). 2. nature-proofing. As mentioned above, the wind gets faster the higher you go, and lets not forget earthquakes and stuff. 3. making financial sense. Most super-tall buildings cost so much to build that it would have been cheaper to build two buildings half that height, even after buying more land. (As also was noted above) ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [April 30, 2014, 2:50pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/55 "2014-04-30T14:50:48Z")
> [@TroutMan](#): > > Randall Monroe tackled this question today in his [What If](http://what-if.xkcd.com/94/) series. Can someone explain the ‘Keira’ joke? ---
**Author:** ![SpyOne](https://avatars.discourse-cdn.com/v4/letter/s/82dd89/32.png) [@SpyOne](https://boards.straightdope.com/u/SpyOne)\ **Post date:** [April 30, 2014, 2:54pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/56 "2014-04-30T14:54:55Z")
> [@Exapno\_Mapcase](#): > > There’s no economical way to have all emergency services on call in house 24 hours a day for such a limited population and rare emergencies. I lived in a small city of 15,000 people which had a full-time fire department and 10 police cruisers on duty at all times. I don’t see how making the city vertical instead of horizontal makes that less practical. Any building big enough to have its own zip code is going to need its own emergency services, regardless of how it is oriented. ---
**Author:** ![SpyOne](https://avatars.discourse-cdn.com/v4/letter/s/82dd89/32.png) [@SpyOne](https://boards.straightdope.com/u/SpyOne)\ **Post date:** [April 30, 2014, 3:03pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/57 "2014-04-30T15:03:02Z")
> [@Habeed](#): > > To make this work, you have to have the buildings interconnected horizontally as well as vertically. Instead of 1 single supertower, you need a network of dozens of supertowers. You’d use elevator lobbies, and have skybridges or even automated horizontal elevator cars interconnecting the towers at each elevator lobby level (which might be every 30 -50 floors or so) Dude, skyscrapers _move_. Building skybridges between towers is super hard, because the towers move in relation to each other. They move _a lot_. Wind blowing between the two towers of the World Trade Center would create a low pressure zone that drew the two buildings towards each other, and if I recall correctly the gap between them changing by 20 feet was not uncommon. It would be WAY simpler to make a single tower that is just bigger at the bottom, with tunnels through it for the streets. So the solution to the critical mass problem with arcologies probably isn’t “lots of towers”, but “massive tower” instead. ---
**Author:** ![SpyOne](https://avatars.discourse-cdn.com/v4/letter/s/82dd89/32.png) [@SpyOne](https://boards.straightdope.com/u/SpyOne)\ **Post date:** [April 30, 2014, 3:14pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/58 "2014-04-30T15:14:28Z")
> [@Incubus](#): > > I’ve also heard that the wind hitting the tower will cause it to sway slightly. On higher floors this sway is more significant, so you would get people on upper floors getting “seasick” from the slight motion. This can, interestingly, be partially fixed by the shape of the building. I saw a tv show about two guys who designed a building they called “The Millennium Tower” (because if they could find somebody who wanted to build it, it could be finished by 2000). Their design was round and conical, and wind tunnel testing of a model showed that, accidentally, it was very stable in high winds. I believe they said that as wind hit a large vertical area of the building, say 40 floors, the wind at the top would be faster than the wind at the bottom because the part of the building it was going around was smaller. This caused the wind to effectively hold the top part in place against the force of the wind on the lower part. Maybe I’m remembering that wrong. I saw it a few times, but that was decades ago. If you don’t fix that somehow, “slightly” isn’t the word I’d use. IIRC it is the John Hancock Tower where the residents of upper floors have to bolt their artwork to the walls to keep it from falling as the building sways. Tenants of the World Trade Center near the middle of its height reported windy days making them seasick, of a hallway that was “pitching like the deck of a ship in a storm”, and how anything left on your desk would migrate overnight due to the motion of the building. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [April 30, 2014, 3:23pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/59 "2014-04-30T15:23:46Z")
> [@SpyOne](#): > > But this problem was solved by the time they built the Sears Tower: multiple elevators in the same shaft. So in one shaft there will be an elevator serving floors 1-9, then above it one that serves 10-19, then above that one that serves 20-29 and so on. I don’t know what you mean by this. The Willis (nee Sears) Tower has 16 double-deck (i.e. multiple floor) elevators, but I don’t think it has multiple elevators in a single shaft. In fact. I don’t think any tall building does. There are schemes to accomplish this, like the [Levilator](http://levitators.pejaver.com/Levitators.htm), but I’m not aware they have been put into practice anywhere. Certainly not extensively. > [@](#): > > Then there are express elevators from 1 to 10 or 20. > People would need to change elevators two times to reach their floor (three, for _really_ tall buildings), but each ride would be pretty short, with the last one being the longest (although some folks on the 15th floor might prefer to take the express to 20, walk down one flight, then catch an empty elevator down from 19). This introduces long wait times into almost every elevator ride instead of just some. Wait times are already a limiting factor. > [@](#): > > The big limit on elevators seems to be this: if they accelerate (or decelerate) faster than 1/10g, that will cause some people to vomit. Sears Tower found this out, and had to slow their elevators down. The Willis Tower elevators - they have 104, BTW, top out at 8.1 m/s. The Taipei 101 building has elevators that top out at 16.8 m/s. > [@](#): > > The elevator problem got solved decades ago. I disagree. > [@SpyOne](#): > > I lived in a small city of 15,000 people which had a full-time fire department and 10 police cruisers on duty at all times. I don’t see how making the city vertical instead of horizontal makes that less practical. The emergency needs for a tall building are different from those of a city of separate smaller builders with varying degrees of construction safety built in. > [@SpyOne](#): > > Dude, skyscrapers _move_. > Building skybridges between towers is super hard, because the towers move in relation to each other. They move _a lot_. > Wind blowing between the two towers of the World Trade Center would create a low pressure zone that drew the two buildings towards each other, and if I recall correctly the gap between them changing by 20 feet was not uncommon. The Petronas Towers in Kuala Lumpur are connected by a skybridge that is designed partly to increase support during sway. The World Trade Center towers swayed from 1-3 feet in a heavy wind. ---
**Author:** ![Siam\_Sam](https://avatars.discourse-cdn.com/v4/letter/s/d78d45/32.png) [@Siam\_Sam](https://boards.straightdope.com/u/Siam_Sam)\ **Post date:** [April 30, 2014, 3:39pm UTC](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485/60 "2014-04-30T15:39:41Z")
I’ve heard that the sway in skyscrapers helps them during earthquakes, that because of it the building stands a better chance of riding out an earthquake than does a low-rise building that ends up a pile of matchsticks. True or no? [Previous page](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485.md?page=2) [Next page](https://boards.straightdope.com/t/what-is-the-practical-limit-on-tall-buildings/686485.md?page=4)