Since building a taller building allows you to split the cost of the land by that much, there must be a reason that tall buildings are not ubiquitous. In my city, few buildings are above 3 stories (+basement level).
I understand that above a certain number of stories, you need elevators and that those imply a significant surface sacrifice. After how many stories do they become a practical requirement?
What are the other sources of costs increases for taller buildings? Are there thresholds beyond which some costs increase significantly?
Elevators aren’t just a problem with surface area. Speed and capacity become a real issue the higher you get. Really tall skyscrapers sometimes need multiple stages of elevators to get from the ground floor to the top floor because it isn’t practical to build a straight elevator shaft that runs the whole vertical length of the building. Elevators aren’t just for people either. You need freight elevators to move the larger things and the shafts introduce engineering and design challenges.
There is are also safety concerns like fast evacuation plans and engineering concerns like water pressure and plumbing performance on the higher floors. All of these things can be worked out if you have to but that brings us to the next point. There isn’t a shortage of land in most places, especially the U.S., enough to make it worthwhile to build really tall buildings. Manhattan is an exceptional case because they really do have a land shortage but the skyscraper was an odd fad and they were built in places they weren’t needed. That probably won’t be the case as much in the future.
Most cities have much more stringent building code requirements for buildings over 4 or 5 stories. Besides elevators, you now have greater foundation and structural costs, fire safety and exiting requirements.
Additionally, you have a zoning code that limits where such buildings are allowed, and a limited number of Americans interested in living in them.
The John Hancock Building in Chicago (one of the world’s tallest buildings) has at least one elevator that runs from the ground floor to the observation deck.
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It’s not a matter of it being physically impossible, but rather a matter of making sure that someone who works/lives on the 74th floor doesn’t have to make 72 stops between the ground and his/her destination. If I remember correctly, the elevator up to the observation deck at the John Hancock Building is dedicated solely to taking people from the ground level up to the 94th floor. In fact, the Hancock was also the first building to use a sky lobby and multi-stage elevators.
The cost per-floor grows as you go up since you need architects who can build such massive buildings without them collapsing, blowing over, having too much pressure and blowing out its own windows, etc. so you have to pay what the architects who have those skills charge – which will be much higher than a run-of-the-mill architect’s; you need to have a blend of materials that are heavy and strong at the bottom, but light and of minimum strength at the top and other such engineering specifics that add complexity (which equates to cost); you need to dig a lot deeper to get a proper foundation; etc.
Unless there’s a great demand for businesses be within a particular, small geographic area, you actually can’t compete with smaller buildings. You can throw up a small building more cheaply per floor, which means that you charge tenants less.
Frank Lloyd Wright was neither the first nor the last to propose a mile-high tower but he’s the most famous. That Wiki page summaries pretty much the same arguments made here.
There are additional social factors that come into play. How many people need to live or work in such a building to make it profitable? How do you transport them to the building if they don’t live there? Would that many people overwhelm sidewalks, buses, subways, etc.? How do you feed, service, employ that many people? What does a building that size do to the streetscape? (New York was particularly plagued by the shadows thrown on its narrow streets by tall buildings.) What about the wind effects that create powerful breezes at street level? What are the power consumption needs and how does the building tie into the rest of the system? What environmental factors have to be taken into account?
Tall buildings are a particular ecosystem. They can only be made economically feasible in situations of enormous population density. (Dubai is learning what happens when you build supersized buildings out of vanity and an economic downturn hits. Though you need to remember that the Empire State Building was called the Empty State Building because it was never even half-filled in the first decade after it was built.) There are lots and lots of middling height buildings even in New York. They are simply more economical. (There are many books about building the Empire State Building that get into the economics of the day. Oddly, the economics have changed little over the decades. You can see that by the way single-story malls, factories, and schools spread over cheap land in the suburbs. There is an inverse relationship between the price of land and the number of stories economical to build.)
The practical limit for buildings pre-elevator was six or seven stories. The poor were the only people willing to walk up that many stairs to the top. (This model started in ancient Rome.) Elevators turned buildings upside down. The highest floors were now the most desirable. But there’s still a limit of how much time and trouble people are willing to spend just to travel to their very high apartment or office. The higher a building gets, the more limited the audience willing to make the tradeoff. There is no specific formula, since it depends entirely on location, time, fashion, and purpose.
Wright also wanted to build his mile-high tower in Phoenix. Even as recently as the last decade, I’ve heard plans floated to build it on the outskirts of the Valley. The problems that always seem to kill this project are: 1) the FAA considers it a flight hazard and 2) The building would have more office space than all the other buildings in the valley combined. This would make it impractical to fill.
I saw it pointed out in the wake of 9/11 that no building code in the world would allow a quarter-mile long one-story building with exits only on one end. And yet, turn it on its side, and that’s fine.
Yeah, like above 1 story.
ADA requirements for handicapped accessibility pretty much require elevators in any building over 1 story. Plus if any of your customers are elderly, fat, or lazy, they will also expect you to have an elevator in the building, or lose their business.
Anyone who’s ever played the SimTower game will know that it’s all about the elevators.
If you have a lot of elevators to give speedy service to all floors, you wind up with more elevators than usable (eg: income-producing) floor space on the lower levels. I’ve been in plenty of buildings where there’s about a 25-foot wide span of floor space from the building core to the windows. With all of the other mechanical systems needed, you can easily have
If you have elevators that stop at every floor, people get cranky and soon start to look for other buildings to move to. If you make people take a series of elevators to get anywhere, such as an express from the lobby to the 50th floor skylobby, then another express to the 75th floor, then walk down the hall and around the corner to get a “local” that will take them to their 89th floor office, they get crabby. The first time or two that they do this, they’ll also get lost. They get really peeved if they need to go all the way back to street level and back up if they need to go from their 89th floor office to their dentist on the 32nd floor.
Another limitation that nobody’s mentioned yet is humans. Not everyone wants to be in a tall building, especially when it starts swaying in the wind, and there are plenty of people who just panic at the thought of being 100+ floors up.
The ultimate limitation in the United States is the FAA - they set maximum heights to not be hazards to aviation. Limits vary from place to place, depending on their proximity to airports. I believe their ultimate limit is 2000 feet.
But middling in much of Manhattan is 20 stories, right? Does anybody know how to calculate the optimal number of floors for a given building site? Presumably it rises with the cost of land. Ok, the answer probably is, “There’s no strict formula”, but surely there’s an underlying relationship.
Very tall buildings rarely have a single tenant or a group of tenants that benefit from networking. Does anybody know the tallest building with a single tenant? I understand that the building with the greatest volume is owned by Boeing and is used to construct the 747, etc.
Can you imagine living on the top floor of a 100 storey building in a power failure? in my office building, there was a false fire alarm (students like to do this during exams–or just for the hell of it) and they were having trouble restarting the elevators after the alarm was canceled. I had been teaching in a basement classroom, so I didn’t have my coat or backpack. Eventually I walked up to the ninth floor to get my stuff. No fun.
These incredibly tall buildings are just fancy prestige items. I once read somewhere (sorry, no cite–it was a long time ago) that the physical limit for a building built of stone was 500 storeys, about a mile. Doubtless better materials would allow you go higher.
I once heard–I cannot vouch for this–that when the Calgary Tower was built one foot higher than the CN Tower in Toronto, the CN simply excavated 2 feet from the base of their tower. Illustrating how much of this is prestige.
Yes, highrise developers. They are pretty good at solving the multivariate equation of what the land costs, what the market will absorb, how much construction costs will increase, what the zoning will allow, how much unrentable core there will be, how much windowline to floorplate they will get, and how long it will take to deliver the building to the impatient preleased tenants.
In Chicago, with 330 x 330-foot blocks, the sweet spot for an office highrise seems to be about 50 stories or 1,000,000 sq feet on a quarter-block site. That’s small enough that you can get two or three big tenants preleased (about a quarter of the building), so the bank will lend you the money—but you generally have to deliver the space in 30 months or less. You can serve it with only two elevator banks and two escape stairways so you have an efficient core layout. The office floors don’t end up too deep to lease or use efficiently.
One of the more severe airport flight path limitations is that affecting San Jose, CA. Buildings in the downtown core are limited to about 300 feet. The downtown is directly in the flight path of the airport, which is only two miles away. Probably contributes to the perception of San Jose being much smaller than it is - no impressive skyscrapers in its skyline, with a lot of buildings at about that limit:
OTOH, while Mineta is a crappy airport in many regards, having an airport that isn’t located somewhere 20 miles out of town has its advantages.
I’ve been to lots of science fiction conventions that overwhelmed the elevator system in hotels. When I was young I could walk down from the 20th floor. Today I couldn’t do it from the third. It’s a serious issue.
Stone hits its height limit in 5% or less of a mile. That’s why all those medieval cathedrals need buttresses to stay erect. Only modern materials could possibly work, and it’s not even sure that the steel of the era would have sufficed when the Empire State Building was built.
The Calgary Tower was built many years before the CN Tower, and is hundreds of feet shorter.
You may be thinking of the height race between the Chrysler Building and the Empire State Building (and a building on Wall St.) in which stunts and last minutes changes were an ongoing part of the process to come up with the tallest building.
Another factor is finding enough matching steel girders in naturally-occurring formations of girder ore.
Or at least that’s what Rosie O’Donnell seems to believe, since she asserted “steel doesn’t melt” in reference to the WTC collapse. Apparently we have to find pre-formed steel parts, since we can’t melt them and cast, extrude, weld or form them.
Thus large skyscrapers are only built occasionally, when a lucky find of pre-formed steel in the right sizes and shapes permits.
Also, there is the question of tectonic stability.* I personally don’t feel comfortable being up too high, because a small part of my brain is always aware of the possibility of The Big One hitting, and it tends to get noisy and panicky if I get too far above or below surface level. I know that seismic reinforcement technology has continued to improve, but still - given the option, I’d prefer to have as few floors above or below me as possible. I don’t think I’m alone, either. It’s part of why, despite the high real-estate prices, we don’t have many skyscrapers in L.A., nor do we have much subway. The fact that we literally cannot trust the ground we walk on has impacted local archetecture quite a bit.
*Does not apply in all parts of the country.