An elevator in a Chicago skyscraper fell 84 floors, requiring a dramatic rescue

https://www.washingtonpost.com/nation/2018/11/19/i-believed-we-were-going-die-an-elevator-chicago-skyscraper-fell-floors-requiring-dramatic-rescue-six-people/

by danso • 8 years ago

203 144 8 years ago

washingtonpost.com

bradknowles• 8 years ago

Pay walled.

neonate• 8 years ago

Incognito.

Simulacra• 8 years ago

A great article on elevators, their construction, and uses is worth a read and found here: https://www.newyorker.com/magazine/2008/04/21/up-and-then-do...

jamesrcole• 8 years ago

That's a pretty misleading headline. It wasn't a free-fall, and it doesn't sound like the passengers were even injured when it came to a stop.

From the article: The malfunction had been caused by a snapped “hoist rope,” or elevator cable, Maloney said. Other cables were still attached, keeping the elevator from plummeting to the floor.

elhudy• 8 years ago

I was under the impression that the way elevators are designed, it's physically impossible for them to free fall upon failure.

Source: documentary on the first elevators

jsiepkes3• 8 years ago

There are indeed a whole bunch of security features which prevent a lift from free-falling.

However there is another risk of it flying up and slamming into the ceiling for most types of lifts. For that kind of malfunction there is often no safe guard. A lot of lifts are of the type where they use a large weight which is about half the weight of the maximum load capacity of the lift. This weight is used as a contra weight and hangs in the elevator shaft (so it goes down if the lift goes up). If the brakes in the engine on top of the lift shaft fail there is nothing stopping the contra weight and the lift will fly up.

This is a YouTube video of that happening: https://youtu.be/Ys0rDAxdd-g (warning its not graphic but obviously a disturbing thing to see)

craftyguy• 8 years ago

The title says nothing about free fall or injuries, you did.

nabla9• 8 years ago

Elevators don't go into free-fall even if all the cables are cut at once. The safety chain is just one of the two or three safety measures.

The clack-clack-clack sound they reported was probably safety clamps attached to the rails. When the speed of the elevator exceeds some limit they start automatically breaking.

codeisawesome• 8 years ago

While it must have been a terrifying experience - the headline makes it sound like the thing fell 84 floors to Zero - it actually stopped at floor 11 so the safety mechanisms kicked in. Thanks goodness.

SkyMarshal• 8 years ago

True, thought the fact that it took 84 floors for the safety mechanisms to kick in seems problematic. What heuristics did those automated mechanisms have to work through before triggering, and why did they take 84 floors to do it, I wonder.

hn_throwaway_99• 8 years ago

Yeah, I was really hoping the article would address this. Were the safety measures designed to kick in at the 11th floor, or were the passengers just lucky that they were at the 95th floor instead of, say, the 80th floor when the elevator took 84 floors for the safety measures to stop the elevator?

marcinzm• 8 years ago

My guess is that there's some sort of velocity/acceleration threshold. So since the elevator car was still attached by other cables it didn't fall fast enough to trigger the mechanism earlier.

thaumasiotes3• 8 years ago

Clearly, it didn't take 84 floors for the safety mechanisms to kick in. If it had, the passengers would have been in free fall for 84 floors, and suffered the same physical consequences as you would if you jumped off the 84th floor of a building.

Falling 84 floors isn't less dangerous if you end 10 stories above the ground than it is if you end on the ground.

sparrish• 8 years ago

OK, I'm going to avoiding elevators for a while now. I shouldn't have read that.

tdeck• 8 years ago

Cable elevators are one of the safest vehicles you can be in. In fact, I wouldn't be surprised if they were safer than taking the stairs. There are so many redundant safety mechanisms in there you should feel extremely safe.

rococode• 8 years ago

You can look at it from another point of view: elevators have so many safety mechanisms nowadays that they can fall 84 floors and still not cause any injuries to their passengers.

icebraining2• 8 years ago

Plus even such a "non-event" is news, because it happens to rarely.

starpilot• 8 years ago

Yeah, I'd be way more interested in the safety mechanism behind how these people got out unscathed vs the rescue effort. This is really impressive engineering.

snuxoll• 8 years ago

Per mile travelled, (modern) elevators are literally the safest form of transit ever developed by our species. They are rather impressive devices from a safety perspective, somebody else linked the video in the thread so I'll chime in and say I highly recommend the defcon video "From the Pit to the Penthouse".

th0ma5• 8 years ago

Otis said in a PBS special that the only people that die in elevators in the US anymore are people that work on them, unfortunately, but even that is only a few each year. I do remember an accident several years ago at Ohio State where some students were crushed at a dorm by trying to stuff it full. Anyway, like others have said, they're statistically safer than many other things.

slavik813• 8 years ago

I was browsing through a list of elevator accidents a while back and noticed that the two main causes of death seemed to be people stepping blindly into empty elevator shafts and people who tried to get out of the elevator when stuck.

So, my recommendations for elevator safety are: watch where you're going, and wait for help to arrive if there's an elevator malfunction.

ams61103• 8 years ago

I never understood the stepping into an empty shaft, because AFAIK the outer doors are opened by the inside doors on the car. So they can't open on their own if the car isn't there. Might be possible on older elevators with manual doors?

mrnobody_67• 8 years ago

thanks for the tip

Doxin6• 8 years ago

As long as you don't step into an empty shaft or fuck around with the doors if the elevator is stuck between floors your risk of injury is just about 0. The lift in the article didn't fall 84 floors, that'd have kicked in the governor. A lift is still perfectly safe if a single cable snaps.

Rjevski• 8 years ago

No-bullshit link: http://archive.is/BDOWO

Also I'd like to point out just how scummy this site is. The paywall offers a "Premium EU Ad-Free Subscription" with the following perk:

No on-site advertising or third-party ad tracking

But trying to buy it paints a whole different story:

By subscribing, you agree to the use by us and our third-party partners of technologies such as cookies to personalize content and perform analytics. Please see our Terms of Service, Digital Products Terms of Sale and Privacy Policy for more information.

Assholes.

yesenadam3• 8 years ago

I learnt a lot more than I ever wanted to know about every aspect of elevators from Elevator Hacking: From the Pit to the Penthouse with Deviant Ollam (who seems to be like a professional elevator pen tester) & Howard Payne, from DEFCON 22. Highly recommended. You'll be talking elevatorese like a pro after you watch that.

https://www.youtube.com/watch?v=1Uh_N1O3E4E

IIAOPSW• 8 years ago

I've watched it twice before. I also recommend "This key is your key, this key is my key"

https://www.youtube.com/watch?v=a9b9IYqsb_U

Deviant is a pentester focused on physical sec. Not just elevators.

Bayart• 8 years ago

There's also his "The Search for the Perfect Door" talk https://www.youtube.com/watch?v=4YYvBLAF4T8

yesenadam3• 8 years ago

That key one is crazy. (i.e. most 'security' using keys seems to be nonexistent) Surely there must be less crime and criminals around than one is led to believe, or this system wouldn't last a day, let alone decades.

borgel• 8 years ago

Yes! This talk was fantastic!

unixhero• 8 years ago

You are not wrong. That is an excellent talk. Maybe one of the very best conference talks I've watched.

But in fact, an ever better version of the one you posted exist.

The non-sensored, +1 hour expanded version from the HOPE X con. Elevator Hacking: From the Pit To The Penthouse [Duration: 1h55min]

yesenadam3• 8 years ago

Ohh thank you! I suspected the one I saw was longer than 1 hour. Here's the link to the HOPE X one you mention:

https://www.youtube.com/watch?v=rOzrJjdZDRQ

333c3• 8 years ago

Little off-topic, but from the article:

“This is the second most important building in Chicago? And this is the third most important city in the United States?” he questioned.

By what metric is Chicago the third most important city in the United States? I'd argue that NYC and DC are the top two (not necessarily in that order) and either San Francisco or Los Angeles (or both) also rank above Chicago.

Thoughts?

adjkant9• 8 years ago

I have a good friend from Chicago and IMO the midwest is a bit of a cult and Chicago is the epicenter of it. The practical result of this is a lot of local pride in Chicago. Chicago is the city that represents basically all of the Midwest from an urban perspective while other regions usually have multiple epicenters.

I can't find the stat at the moment but I believe there's an abnormally high return rate for people born in the Chicago area to come back to it. It's even very cyclical where young people live in the city, then they move out to the suburbs, have kids who go to college somewhere like OSU or Michigan then come back and work in Chicago and the cycle repeats. Nowhere else really has such a clear cycle like Chicago does, and I think it's because of the way Chicago is viewed by people in the area. Don't get me wrong it's a solid city but in terms of cities in the US I'd want to live in it probably comes out to #6 or so. In importance, I'd agree with your assessment as well.

All of this to say that I think Chicagoans find some odd reasons to put themselves high up in importance. I've heard a lot about O'Hare being the air travel epicenter of the US where every connecting flight goes through, the (now fading) financial epicenter Chicago used to be, a top food scene, the list goes on. I think it has local importance and I think locals have a bit of a chip on their shoulder about others not viewing it as being so important.

Edit: It's unclear if this is a local or international tourist in this specific case. Curious what the perspective is for an international tourist on the criteria.

camjohnson26• 8 years ago

It’s the 3rd largest city by population. I think that’s where they’re getting the number.

333c3• 8 years ago

Thanks for the frank perspective! I'm a California native currently in my first year of college in the Midwest, so I'll have to keep an ear out for this attitude about Chicago.

almost_usual6• 8 years ago

Chicago has the third largest population and GDP for a metro area in the U.S.

The Bay Area ranks 6th in the U.S. GDP wise. Dallas Ft Worth and DC are both higher.

If you’re ranking cities by tourism I’d think Chicago would fall below SF or DC.

vasilipupkin4• 8 years ago

you seem to be obsessed with assessing Chicago's importance - more so than anybody I've ever met from Chicago

here is importance not by population, but by GDP https://en.wikipedia.org/wiki/List_of_U.S._metropolitan_area...

wenc2• 8 years ago

All of this to say that I think Chicagoans find some odd reasons to put themselves high up in importance.

This comment doesn't ring true in general.

My experience is that most Chicagoans usually correctly rate their city. Chicago has been historically perceived as one of the great American cities, with indisputably great achievements (Chicago architecture, economics, transportation, mercantilism, etc.). And today, people love living in Chicago because it's a major cultural center that has many things to offer over smaller U.S. metropolitan areas, while still being much more affordable than coastal cities.

But unless they are very young, immature and non-world-savvy, most Chicagoans usually also confess there are problems with crime, crooked politicians and (ever increasing Cook County) taxes. Chicago today feels like NYC in the late 80s, but with modern infrastructure.

Not that many Chicagoans will gush unreservedly about their city. Chicago is not the kind of city that invites unexamined boosterism.

debt• 8 years ago

“but in terms of cities in the US I'd want to live in it probably comes out to #6”

Ah so you’ve never lived in Chicago then

slyfocks• 8 years ago

The Chicago metropolitan area is not only the third most populous in the U.S., it also has the third highest GDP by a fair margin.

More generally, it tends to be regarded as a much more global city than SF or DC. New York is clearly #1 as far as international importance, but Chicago generally places third behind LA in any serious ranking of U.S. cities based on economic and cultural importance.

almost_usual6• 8 years ago

If you look at GDP ranking Chicago comes 3rd in the U.S.

Also, the 3rd most populous city in the U.S.

Metro area rankings by GDP are the following.

https://en.m.wikipedia.org/wiki/List_of_U.S._metropolitan_ar...

phil21• 8 years ago

What is the metric for ranking? By my metric, DC doesn't really qualify as a city - it's a giant barely functional suburb. Most metro areas in the US would seem to be similar.

But my ranking is irrelevant really. Most silly rankings like this put chicago around #3 based on population/GDP/transport/etc.

For me - it's one of maybe 3-4 cities in the entire US where you can live comfortably without a car - meaning there is at least semi-competent public transportation at a "World City" level. LA, SF, and DC don't qualify at all by that metric so I'm not sure how useful it is :)

I guess in my minds eye I put the "top 3" cities in the US as NYC, LA, Chicago in that order - but it's also based on somewhat dated and historical information.

Redoubts• 8 years ago

Top 3 are NYC, LA, and CHI by any measure. Not sure why SF was even mentioned, it doesn’t even place.

mcguire• 8 years ago

Population.

https://en.wikipedia.org/wiki/List_of_United_States_cities_b...

mikekchar2• 8 years ago

Kind of random and OT, but I remember a long time ago thinking about the safety of staircases. I was in a mall and on the top floor there was a movie theatre. To get to the movie theatre, there was a staircase which bridged the 4th and 5th floor. The staircase was literally a bridge that spanned over a central atrium. It wasn't suspended or supported by anything -- it only stayed up due to the rigidity of the structure. The movie theatre didn't like people crowding the lobby, so they had the queue go down the staircase. I remember thinking, "I wonder if the architects/engineers considered the possibility that there would be 3 people standing on every single step of this staircase". As far as I could tell there was no indication of what kind of load it could take. It never broke, so I guess they did think of it, but I never wen to that theatre. Waiting on that staircase was waaay too scary for me :-)

jonp888• 8 years ago

They do think of that. I've seen old bridges where extra barriers had been installed to prevent the full width being used because it was judged not capable of supporting the weight of being filled with people by modern standards.

On the other hand, sometimes it all goes wrong: https://youtu.be/VnvGwFegbC8

wiredfool• 8 years ago

There were a series of issues with the Hyatt Regency walkways, and at this point I'd expect every structural engineer knows the story.

1) The engineer designed something that was not easily buildable. (The bridge had to be jacked 2 stories up along threaded rods that supported it, and nuts rotated up that distance)

2) The contractor modified the design in the shop drawings to make it more buildable, (split the threaded rod into two sections, with the lower half hanging from the upper walkway) but in doing so doubled the stress on a particular piece that itself was replaced by a less capable similar item. (box section vs welded C sections)

3) The Engineering firm signed off on the change to the shop drawings without realizing the significance of the changes.

Nikaoto2• 8 years ago

What does OT stand for?

Jonnax• 8 years ago

Off topic.

the_mitsuhiko• 8 years ago

I wonder if the architects/engineers considered the possibility that there would be 3 people standing on every single step of this staircase

I find it interesting that you assume they did not. The job of a structural engineer is to ensure exactly that.

tialaramex• 8 years ago

You say that, but there will be a document somewhere telling people what the requirement is, and it will probably NOT say "Imagine the maximum possible amount of people that could physically fit, now add ten percent". And you might even find you need to track down the rationale in the engineering paperwork to know if the structural engineer envisioned this as a route crammed full of people or just a fun decorative element of the building that would technically be open to the public but rarely used. Not everything, build everywhere has to obey the same loading rules, many private homes have stairways that would be far too narrow, steep and poorly lit to be legal in commercial buildings for example.

When there was a balcony collapse in a foreign country I got interested and read the code where I live, the building regulations specify that a balcony or similar structure, which essentially hangs off the side of a building and so is unsupported at one side, must handle up to a certain load per square metre. Enough that a modest residential balcony can certainly hold two lovers, someone's spare bicycle and the decorative concrete flower beds they've put down to make it feel "outside". But what if instead of two lovers standing under the moonlight it's as many of the university rugby club as will physically fit? Ah, well then you're going to exceed the designed capacity and a code-compliant balcony might very well collapse.

All those tower blocks in England that are being retro-fitted because of the ones that burned down in London, their architects would have told you at the time they were definitely built to code, no extraordinary risk of fire. Then a bunch of people die in an out-of-control tower fire and - surprise - the politicians now claim the code meant you shouldn't ever have done that, and those towers were all built wrong but now they need to "clarify" the meaning. Sure.

mikekchar2• 8 years ago

I'm a software developer :-) What we usually call "software engineering" often doesn't take these kinds of issues into consideration. Even when I've worked with actual engineers (including P.Engs) the amount of "engineering" I've seen in my career as been vanishingly small. For example, I've worked in real time systems and we've had a performance budget. The number of times I've asked, "What did you do to ensure this will fit in the budget" and had people reply with something like "My code is fast. I don't think anyone can make it go faster" is ridiculous. Over time I've developed a kind of doubting attitude -- unless I see some evidence that you've done the due diligence, then I assume you've not.

Of course, what's common in my industry would obviously be fatal in other industries. I often tell my wife, "I don't have an unreasonable fear of heights. I have an unreasonable fear of engineers" :-) Still, I haven't died from having a bridge collapse under me yet, so I must be doing something right!

ubernostrum• 8 years ago

Relevant to your question: https://en.wikipedia.org/wiki/Hyatt_Regency_walkway_collapse

jaclaz• 8 years ago

JFYI (and it may depend on each country's building regulations) -anything (being it slabs, rooms, corridors, terraces, staircases) in "public" buildings is required by norm to be calculated for a "dense crowd" (cannot say if that is the proper term in English) which equates usually to between 400 (static) and 600 Kg/m2 (dynamic).

This roughly equates to 4-6 people per square meter.

shrumm• 8 years ago

This reminds me of an undergrad assignment I had when taking real time C programming. We were each given a programmable lift controller that looked very lego-ish. We were meant to write a multi threaded C program to react in real time to button presses etc to control the lift. I finished and tested every scenario i could think of - it worked great. Was feeling pretty proud of myself.

The professor gets to my table, presses a few buttons and everything works fine. He nods to himself. Then he starts yanking wires out and the lift kept going. He looks at me, shakes his head and says “safety”. I forgot to make the lift stop if anything unexpected happened :)

Thank goodness there was a safety system on this lift, even if it had to fall 84 floors for it to kick in.

tachikomagenius• 8 years ago

They were really lucky. If they were 12 floors lower then it would have ended horribly. I wonder why didn't the emergency brakes work immediately. Shouldn't it clamp down as soon as any elevator cable snaps?

icebraining2• 8 years ago

If they were 12 floors lower then it would have ended horribly

It's not clear how fast they were falling; it may be that the brakes didn't kick in because the fall was slow.

InclinedPlane• 8 years ago

They probably weren't going fast enough for the brakes to kick in.

aaaaaaaaaab• 8 years ago

Multi-threaded program for controlling safety-critical systems? What could go wrong...

jhbruhn• 8 years ago

This is were time-triggered architectures [1] can kick in! You divide your program into tasks and messages passed between tasks, and can then assign each task to a separate processor with a precise execution time. Same goes for messages.

[1] https://pdfs.semanticscholar.org/8e26/a95a24569b284271a54397...

yk• 8 years ago

You just need to acquire the global elevator lock.

mirimir• 8 years ago

From Rjevski's "[flagged] [dead]" comment: http://archive.is/BDOWO

Otherwise, I couldn't have read the article.

parliament32• 8 years ago

Thank you, same here.

nwah1• 8 years ago

For anyone getting a paywall.

https://www.latimes.com/nation/la-na-chicago-elevator-fall-2...

PeterStuer• 8 years ago

The LA Times has the 'fuck your privacy rights' wall.

larkeith• 8 years ago

(Solution: disable javascript for no paywall or accept-cookies wall on either. Also helps against tracking.)

anotheryou2• 8 years ago

don't they have automatic brakes that activate through centrifugal force when the cabin moves too fast?

Doxin6• 8 years ago

Presumably the cabin didn't move too fast. An elevator doesn't just snap a cable, drop 84 floors in freefall, and only /then/ apply the brakes. A lift isn't suspended by a single cable in any case, it's suspended by 7. I suspect the media is making this all sound a lot more exciting than it was in reality.

anotheryou2• 8 years ago

It's more than one cable?

I had a cable slip on my once... doors open it went down until it bottomed out. (and faster than normal, but far from free-falling)

cesarb• 8 years ago

The article says they were in a blind shaft, which made the rescue more complicated. In the WTC bombing (http://www.interfire.org/res_file/pdf/Tr-076.pdf), there were also many people stuck in elevators in blind shafts, also complicating their rescue. Perhaps there should be a requirement to have an inspection access every other floor on blind shafts, to make rescue in these situations easier.

qaq• 8 years ago

On the bright side everyone is OK and soon will be significantly richer.

empath75• 8 years ago

Lol not likely. What are their damages?

HashBasher• 8 years ago

How far would an elevator have to fall to entirely take out a building?

SomeHacker44• 8 years ago

My intuition is that no elevator could destroy its building even in free fall. Considerations: terminal velocity (air drag, weight, friction on the rails), mass, the surrounding part of the building, etc. Even a very heavy elevator in a half mile tall building would seem to be relatively low energy.

10,000 kg hitting at 400 km/s is equivalent to about the energy of 15 kg of TNT. The first WTC bombing was much more and the building withstood it.

petee• 8 years ago

Because the elevator decended 84 floors doesn't mean the cable snapped immediately at the start -- express elevators are fast and shakey, there's no way to determine at what floor the cable actually snapped.

It could have accelerated too fast, and the cables snapped only when it started to slow down, which it probably would have anyways for the remaining 10 floors. they may have only free fell one or two floors, if at all. Cable probably snapped just before they started to hear the clack clack clack

bonyt• 8 years ago

I once spent an hour or so trapped in an elevator. It was a small building, only six stories or so. A bit of a rumble, and it was just stuck, a few inches out of alignment with the exterior door. I didn't know it at the time, but the elevator had actually fallen up, because it was counter-weighted and I was alone inside, well below its weight limit. It was very old and a relatively small building, so I had no idea that this happened, and I thought it was just jammed at my destination on the first floor.

The emergency brake had kicked in at the top floor, but the doors wouldn't open when misaligned like that. Most of the time I spent in there was the technicians (and, for some reason, they sent the police to talk to me) looking for me. I had thought I was on one of the lower floors, and that's what I told the person on the emergency phone, so they were looking for me in the wrong place.

The elevator was old enough that I guess it didn't have any mechanism for reporting its location, and may have even been a relay-controlled system, which explains why they couldn't find me. After they showed up, it took a fair bit of prying on both sides to get the doors to open. I was surprised when I left and found out that I had been on the top floor the whole time, as they didn't tell me until I was freed. Then I took the other elevator back down to the lobby with the technicians, showed my professor the card from the police officer and explained why I missed class.

The one thing I wonder while reading the article is how they managed to figure out where the elevator was if it was in a blind shaft - they couldn't just go from floor to floor listening like they did for me. I used to live in an apartment in at all building that shared a wall with a blind elevator shaft, and I didn't even realize it for a while because the walls were so thick that the shaft was silent.

TheSpiceIsLife• 8 years ago

The one thing I wonder while reading the article is how they managed to figure out where the elevator was if it was in a blind shaft

Can't the technicians just open any of the outer lift doors and have a look?

mmsimanga• 8 years ago

And what did the professor make of your excuse for missing class?

An elevator in a Chicago skyscraper fell 84 floors, requiring a dramatic rescue

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