How not to floating crane (video). - Page 1
Forum section: electronics / general

author: ElectroIrradiator
author_rank: Frequent Contributor
timestamp: August 03, 2015, 06:35:57 pm
content: This happened today in The Netherlands. Discuss.

author: Ian.M
author_rank: Super Contributor
timestamp: August 03, 2015, 06:54:47 pm
content: Somebody %%%%ed up their stability calcs. The problem with using ordinary cranes afloat is the smart load safety alarm systems assume the crane is on a fixed surface. It might have gone better if a spud (jackup) barge has been used.Seehttp://www.independent.co.uk/news/world/europe/netherlands-crane-collapse-at-least-20-injured-as-equipment-falls-on-houses-10435877.htmlfor coverage in English.

author: rx8pilot
author_rank: Super Contributor
timestamp: August 03, 2015, 07:00:31 pm
content: 1. I hope that everyone survived.2. The bkg music is hilarious considering what just happened.3. Looks/sounds like a mechanical failure from the snapping sound. It will probably not take too long to find the point of failure and decide why it failed. The geometry and physics of a complicated lift are hared to plan especially wind and water. It seems that someone did not understand the dynamics in play and the stresses were focused on a single point. It seems that most crane failures are balance related, but this seems to be a rigging fail.

author: free_electron
author_rank: Super Contributor
timestamp: August 03, 2015, 07:04:04 pm
content: what is the clonking sound just prior to the piece falling ( even before the first crane starts tipping. This sound to me like steel cables that snap ...is it possible the hoist could not take the load, the cables ruptured , the load fell down on one corner , tipping the barge and making the cranes topple ?

author: HighVoltage
author_rank: Super Contributor
timestamp: August 03, 2015, 07:34:16 pm
content: Quote from: free_electron on August 03, 2015, 07:04:04 pmIt really does sound like a cable snapped and added a huge impulse to the load.But then, it seems there was no counterweight on the other side of the barge and something would have happened, even if the cable would not have snapped.

author: nctnico
author_rank: Super Contributor
timestamp: August 03, 2015, 07:37:29 pm
content: Quote from: ElectroIrradiator on August 03, 2015, 06:35:57 pmI used to ride my bicycle over that bridge almost daily for many years... First to school and later on to my first employer. I even got a ticket for ignoring the red light while on by bike (I ignored that red light every day like everyone else). BTW one of the cranes nearly hit the building where the local electronics shop was (now long gone).I think one of the cranes slipped on the smooth surface of the barge. Look at how the trailer moves around like a toy on the barge in the front. It's just plain stupid to put freestanding cranes on a barge like that.

author: free_electron
author_rank: Super Contributor
timestamp: August 03, 2015, 07:59:26 pm
content: Quote from: HighVoltage on August 03, 2015, 07:34:16 pmIf you watch carefully and listen , here is what i make outthe cranes start pulling the bridge piece between them.at 0:14 the first snap is heard , followed by a second one immediately after.at 0:14 look at the surface of the bridge piece and look at the moving shadows on itsomething is clearly moving at high speed judging from the shadows. it looks like a tabilising rod that was held by cables was flung across ( from the shadow movement )at 0:20 you see that the top of bridge piece is no longer horizontal but tilted .. the bottom right corner is lower .. this probably caught something on the deck. further pulling by the back crane caused pressure on the deck making the barge start to list.at 23 the list is enough to destabilise the rear crane and all goes to snot ...i am not an expert but i strongly believe somewhere a cable gave out. that sound at 0.10 is so remarkable.

author: AndreasF
author_rank: Frequent Contributor
timestamp: August 03, 2015, 08:31:13 pm
content: It seems like the workers on the ground were already running almost from the beginning of the video. I wonder if the incident actually began even slightly before what's shown in the clip. Anyway, I hope nobody died.

author: G7PSK
author_rank: Super Contributor
timestamp: August 03, 2015, 08:51:40 pm
content: It looks to me that the slewing was not quite in sync and as the load was moved across from the left to right of camera the crane nearest to camera was pushing the load and other crane I think the noise sounds more like metal clashing on metal than cable snapping which tends to sound more like a pistol shot. Passing loads like that requires very skilled crane drivers.

author: Ian.M
author_rank: Super Contributor
timestamp: August 03, 2015, 08:54:18 pm
content: Watch the first 15 seconds again and pay attention to the crew on the taglines.At 0:04 there's a noise like a chain falling.At 0:05, there's a shout. The crew start running off the barge.By 0:08, the tagline handlers abandon their lines. The far barge starts heeling.Quote from: free_electron on August 03, 2015, 07:59:26 pmAt 0:25, there is a loud clanging noise, the far barge flattens out and the crane starts to collapse.IMHO the lift had gone bad at 0:04.

author: HighVoltage
author_rank: Super Contributor
timestamp: August 03, 2015, 09:19:18 pm
content: Quote from: Ian.M on August 03, 2015, 08:54:18 pmI agree, watching it in high resolution you notice that some crew members know that something is going wrong, very early on in this clip.

author: Ian.M
author_rank: Super Contributor
timestamp: August 03, 2015, 09:38:00 pm
content: Longer video starting 40 seconds earlier:I *THINK* the far barge is starting to heel at 0:32, and the load starts swinging 12 seconds earlier than the chain noise at 0:04 in the other video.

author: rx8pilot
author_rank: Super Contributor
timestamp: August 03, 2015, 09:47:59 pm
content: IMHO, those buildings should have been emptied during the lift. Too many variables to guarantee safety and clearly a fault unfolds in seconds.

author: HighVoltage
author_rank: Super Contributor
timestamp: August 03, 2015, 10:08:00 pm
content: Here are some more videoshttp://www.rtlnieuws.nl/nieuws/binnenland/burgemeester-geen-slachtoffers-alphen-aan-den-rijn

author: BillyD
author_rank: Regular Contributor
timestamp: August 03, 2015, 10:46:46 pm
content: I think this may be the original video shot by webak1, it starts from earlier and runs longer than the one above.It may have been a combination of wind and the larger barge listing. From looking at the birds and a flag in the image, the wind is blowing left to right. You can also hear it on the soundtrack.

author: MikeW
author_rank: Regular Contributor
timestamp: August 03, 2015, 10:55:47 pm
content: The far end of the barge seems quite a long way down in the water relative to the near end.Or is that just perspective?

author: free_electron
author_rank: Super Contributor
timestamp: August 03, 2015, 11:08:57 pm
content: when you hear the guys yelling it looks like the bottom orange part of the bridge is slamming into the rear crane. moments later the top of the bridge slams into the rear crane's arm.so that would be the sound i thought was a cable snapping. there is delay between sound and video ...

author: TerraHertz
author_rank: Super Contributor
timestamp: August 03, 2015, 11:23:56 pm
content: Does anyone know what they were trying to do with it? Clearly lifting it off that slanted support stand (which isn't on the main barge), but then what?Was it supposed to end up standing vertically on the barge, for transport?I think this accident started several days before the event.

author: BillyD
author_rank: Regular Contributor
timestamp: August 03, 2015, 11:32:09 pm
content: Quote from: TerraHertz on August 03, 2015, 11:23:56 pmHave a look at this rather excellent video also by webak1 which was presumably shot very shortly beforehand.My guess is that they were transferring it onto the larger barge, and then going to move the larger barge complete with its 2 cranes about 100m to the background to reinstall it. But once the large barge began to list, nothing could save it.

author: MikeW
author_rank: Regular Contributor
timestamp: August 03, 2015, 11:34:37 pm
content: Quote from: TerraHertz on August 03, 2015, 11:23:56 pmMinor point but transporting anything vertically rarely makes sense.I do agree that this accident started in the planning stages though.Edit: And if anyone says space shuttle please refer to 'rarely'

author: ElectroIrradiator
author_rank: Frequent Contributor
timestamp: August 03, 2015, 11:41:53 pm
content: So each crane was on its own barge.That is an ... interesting solution.

author: idpromnut
author_rank: Unknown
timestamp: August 03, 2015, 11:43:45 pm
content: Looks like a gust of wind (you can hear it on the audio feed) starts the bridge piece moving. It seems that the two cranes + guide holders can't keep it from swinging and an object once in motion, tends to stay in motion. Until hitting a crane.Thoroughly agreed on the planning of this seems cock-eyed at best.

author: nctnico
author_rank: Super Contributor
timestamp: August 03, 2015, 11:45:20 pm
content: Quote from: TerraHertz on August 03, 2015, 11:23:56 pmThe bridge is in the rear. I think they wanted to lift it and then tow the barges to put the moving part of the bridge back in place.Appearantly they removed the moving part of the bridge a couple of months ago using a similar (reversed) method.Quote from: MikeW on August 03, 2015, 11:34:37 pmThe water is too narrow to transport such a large item in any other position. They could have opted for rebuilding the bridge on-site though. It's closed for traffic anyway.

author: TerraHertz
author_rank: Super Contributor
timestamp: August 04, 2015, 02:02:42 am
content: Quote from: BillyD on August 03, 2015, 11:32:09 pmCool video. Yes, from that viewpoint it's clear the bridge section was intended to go into that bridge in the background.Quite a bit of barge and crane shuffling needed to get it there.Anyway... now we know the true cause of accident: Crane operators distracted by quadcopter flying around.Not sure I should be joking about an accident where people were hurt. I'll probably go to Atheist's Hell. See you guys there.But still. This is now my favorite crane accident video. Beating out:Oz big crane accident. Language. Still has the funniest 'Dong!" sound. But the background music in the Dutch vid is excellent.

author: nctnico
author_rank: Super Contributor
timestamp: August 04, 2015, 06:58:22 am
content: According to the latest news nobody got hurt in the accident from yesterday.

author: G7PSK
author_rank: Super Contributor
timestamp: August 04, 2015, 07:58:29 am
content: As I said before it looks like the slewing of the cranes was not in sync and the one nearest the camera was a tad faster than the other, this along with any wind forced the load into the far cranes hydraulic stays and that's the loud clang. The far crane and its barge are clearly being pushed over before the load impacts on the crane.

author: Jeroen3
author_rank: Super Contributor
timestamp: August 04, 2015, 08:21:59 am
content: I think the rotation of the crane was a result of the center of gravity already moving beyond any control.The barges, which are already blamed by many captain-hindsight's, behave as predictable. As soon as the load center moves outside the center line of the barge, it starts rotating. And as soon as that happens the instability is unavoidable.There is a large collective knowledge of people with floating heavy lifting in the Netherlands. Such as Mammoet Maritime.I'd think somewhere a technical failure is to blame. Because IIRC these bridge are often lifted in vertically, since the counterweight has to fit inside the already constructed bridge pillar.At another recently assembled bridge they've "driven" a large span-bridge on a barge to move it the center of the canal. Edit: i've found ithttps://youtu.be/IqVYVKZoryk?t=454

author: ElectroIrradiator
author_rank: Frequent Contributor
timestamp: August 04, 2015, 08:35:14 am
content: Quote from: nctnico on August 04, 2015, 06:58:22 amThat is amazing news. The Danish media is still talking about 20 being injured yet no fatalities.

author: PA0PBZ
author_rank: Super Contributor
timestamp: August 04, 2015, 08:53:28 am
content: Quote from: ElectroIrradiator on August 04, 2015, 08:35:14 amAlready in the first news items about this they talked about 20 being injured, my guess is they all picked this up from each other without knowing where it came from. As it stands now there is one person lightly injured on his leg, he was in one of the houses that were hit.(And one dog was killed...)