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An elevator in a Chicago skyscraper fell 84 floors, requiring a dramatic rescue
- bradknowles 8y agoPay walled.
- neonate 8y agoIncognito.
- Simulacra 8y agoA 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-down https://www.newyorker.com/magazine/2008/04/21/up-and-then-do...
- jamesrcole 8y agoThat'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.
- nabla9 8y agoElevators 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.
- elhudy 8y agoI 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
- jsiepkes 8y agoThere 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 https://youtu.be/Ys0rDAxdd-g (warning its not graphic but obviously a disturbing thing to see)
- SmellyGeekBoy 8y agoWhy wouldn't the counterweight also have its own emergency braking system? Seems like an obvious oversight.
- jsiepkes 8y agoA free fall safe guard is often mandated by law / regulation. A "shoot up slam into ceiling safe guard" is not. That makes it simply a cost thing. Since most people don't know about this risk and there aren't many accidents there is simply too little incentive.
- craftyguy 8y agoThe title says nothing about free fall or injuries, you did.
- codeisawesome 8y agoWhile 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 8y agoTrue, 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 8y agoYeah, 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 8y agoMy 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.
- busterarm 8y agoAs someone who was in an elevator that dropped ~20 floors out of nowhere and then functioned normally (Zeckendorf Towers), I imagine that's true.
- Someone 8y agoThat, and this was an express elevator, so safety features have to kick in at higher speed. Safety features also can’t decelerate the cage too fast. If, say, the elevator fell from floor 70 to floor 40 before safety features kicked in, it makes sense to use most of the remaining space for deceleration.
- sparrish 8y agoOK, I'm going to avoiding elevators for a while now. I shouldn't have read that.
- Doxin 8y agoAs 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.
- deleted 8y ago[deleted]
- tdeck 8y agoCable 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 8y agoYou 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.
- icebraining 8y agoPlus even such a "non-event" is news, because it happens to rarely.
- starpilot 8y agoYeah, 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 8y agoPer 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".
- Rjevski 8y agoNo-bullshit link: http://archive.is/BDOWO 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.
- yesenadam 8y agoI 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 https://www.youtube.com/watch?v=1Uh_N1O3E4E
- IIAOPSW 8y agoI'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 https://www.youtube.com/watch?v=a9b9IYqsb_U Deviant is a pentester focused on physical sec. Not just elevators.
- Bayart 8y agoThere's also his "The Search for the Perfect Door" talk https://www.youtube.com/watch?v=4YYvBLAF4T8 https://www.youtube.com/watch?v=4YYvBLAF4T8
- yesenadam 8y agoThat 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 8y agoYes! This talk was fantastic!
- unixhero 8y agoYou 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]
- 8y ago
- 333c 8y agoLittle 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?
- adjkant 8y agoI 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 8y agoIt’s the 3rd largest city by population. I think that’s where they’re getting the number.
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- mikekchar 8y agoKind 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 8y agoThey 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 https://youtu.be/VnvGwFegbC8
- wiredfool 8y agoThere 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.
- slavik81 8y ago
- shrumm 8y agoThis 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 8y agoThey 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?
- icebraining 8y agoIf 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.
- Doxin 8y agoIt's also very possible they were falling slowly because the brakes kicked in. As far as I know having the lift slowly hit the buffer at the bottom shouldn't be a problem other than having to reset the buffer.
- credit_guy 8y agoThis happened to me as a kid in Eastern Europe about 30 years ago. I was with my parents and my sister, going from a high story to the ground level. We were pretty much at the ground level when the cable broke. There was a sudden jolt, I don't know if it was the brakes engaging, or the cabin hitting the buffer. Then a bit of silence, and after about one or two seconds the cable came crashing on the top of the cabin. I guess the cabin was quite sturdy, that nothing happened. My Dad just opened the doors (they were and still are mechanical, rather than the motorized gliding doors you see in the US), and we left. None of us was harmed in any way.
- mirimir 8y agoFrom Rjevski's "[flagged] [dead]" comment: http://archive.is/BDOWO http://archive.is/BDOWO Otherwise, I couldn't have read the article.
- parliament32 8y agoThank you, same here.
- nwah1 8y agoFor anyone getting a paywall. https://www.latimes.com/nation/la-na-chicago-elevator-fall-20181120-story.html https://www.latimes.com/nation/la-na-chicago-elevator-fall-2...
- PeterStuer 8y agoThe LA Times has the 'fuck your privacy rights' wall.
- larkeith 8y ago(Solution: disable javascript for no paywall or accept-cookies wall on either. Also helps against tracking.)
- anotheryou 8y agodon't they have automatic brakes that activate through centrifugal force when the cabin moves too fast?
- Doxin 8y agoPresumably 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.
- anotheryou 8y agoIt'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)
- Doxin 8y agoYour average elevator has iirc 7 or 8 cables, each individually capable of bearing twice the load of a full cabin. Cable slip is very unlikely (though not impossible). Something definitely went awry in that situation which is very rare.
- qaq 8y agoOn the bright side everyone is OK and soon will be significantly richer.
- empath75 8y agoLol not likely. What are their damages?
- cesarb 8y agoThe 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 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.
- HashBasher 8y agoHow far would an elevator have to fall to entirely take out a building?
- SomeHacker44 8y agoMy 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 8y agoBecause 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 8y agoI 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 8y 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 8y agoAnd what did the professor make of your excuse for missing class?