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Crane fail

old-iron-habit

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Looks to me that they properly evacuated the homes in the cranes danger area before hoisting. That sound practice may have possibly saved some lives. If not, they were damn lucky.
 

Tones

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Wondered if anyone else noticed :D
 

crane operator

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Actually, if you look closely, it seems as if the outriggers aren't extended on the side it tipped to.

They were likely extended all the way, but not pinned. Most of the big AT's have manual lock pins on the outriggers, some guys don't pin them out of laziness/ lack of knowledge. If you don't pin them, when you get close to chart, the crane will "get up on its toes", putting extra pressure on the outrigger extension beams.

When it starts to tip (getting really out of chart- or if it gets shock loaded etc.), the outrigger extension beam cylinders can't hold the pressure of the whole crane standing up on them, and the crane weight will just shove the outrigger beams in, especially if they aren't pinned.

In the pictures this will make it look like the beams weren't at full extension, but likely they were, but with the crane standing up on them, it will just shove them in. My 100 ton you can feel it slide over and pop tension on the outrigger pins when you get close to capacity at larger radius. Its why you need to put the pins in. It kind of startles you when it hits the pins, even when you know its coming.

Just guessing, but the pictures show the crane doesn't have all of its counterweight on. There's a big gap between the upper and lower weight. It wouldn't be the first person to forget to change the computer to the current configuration, rather than the full counterweight setting in the computer. It would be easy to put it up on its toes with less than full counterweight, and not have the computer tell you to stop, if you don't tell the computer the right counterweight.

So- not pinning the outriggers and less than full counterweight. Not a great combination.
 

lantraxco

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Looks like they set it up tight to the curb for a left side lift. Operator might have swung the wrong way, but really with the boom that high, makes me wonder what did actually cause it to tip.
 

crane operator

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Here's a similar incident from this spring in georgia. Big link belt, not all the counterweight on, and a lot of boom out. Got up on its toes, and shoved the front outrigger in, and it landed on the building.

In the second picture, you can see how far he slid over from where his mats were, when the outrigger came in.

I found the billboards kind of ironic.

link belt crane over.jpg link belt crane over 2.jpg link belt crane over 3.jpg
 

crane operator

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i'm not putting the boom over anyone who is not on board with the pick and has to be there.

That's easy to say, not actually always doable. So the other day at the hospital, its seven floors of people. Evacuate all of them? Did a HVAC the other day at a old people's home. Same deal, they aren't moving all those old people on ventilators etc.

The extension we were helping with on the school building, those kids are all in school yet. I wasn't actively lifting over the classrooms, but if something went wrong, I think the classrooms beyond where we were working were occupied. We do a lot of mechanical work on occupied apartment, motel/hotel and condo buildings. We're lucky if we get a few parking spaces to put the crane in, they aren't asking 5-6 floors of guests to disappear for the day, nor are they not booking those rooms.

The guys working in any major metropolitan area face the same issues. Their tower crane might be able to reach 4 other 50 story buildings in a accident, they aren't closing all those buildings down while they build the next highrise. If it all goes bad, they are hitting some other buildings on the way down and there are people at risk.

Same story in the big refineries or a power plant, some guy running a 700ton crawler can hit half of the site at any time, the work goes on around them because there's no way to keep everyone out.

We finished up the big tree job house the other day, and there was a lady home. She asked if she could stay, and I told her I would rather she didn't. I don't think anything is going to come through the roof, but it wouldn't be the first time a big dead branch had fallen off when removing trees. She was fine with that and disappeared for the day. I don't care if she wants to stand across the road and watch, I'd just rather they weren't inside if I can help it.

I'm all for emptying the scene if I can, but it isn't a perfect world. I'm not busting your chops about this, but its easy for a lot of people afterwards to say "there should be no one in a working area of a crane". I just recertified for my crane license, and its easy to read the book and give all the book answers on how everything should be done. But there's always the book answer, and there's what ends up happening in the real world.

And while I'll harp on the fact that this guy probably didn't have his outriggers pinned, I'll confess mine, I cut my own corners:

We do our initial set up on jobsites with the 100 ton on half outriggers, no counterweight, and suspension locked. I'll leave a lot of the suspension weight on the tires, just so I don't punch through with my small mats. Then we use the crane to set my larger steel mats for the outriggers. Its kind of industry standard way of doing it. We do similar just getting in and out of the boom dolly.

But I don't lock my pins on 1/2 when we're doing that. I'm mostly making a "on rubber" pick, with extra stability from the 1/2 outriggers. I don't reach out more than 15-20' of radius setting the mats, and I'd like to think I know what I'm doing. But its not how it shows doing it in the book, because there's no configuration in the book for 1/2 outriggers with no counterweight. But I can't legal travel with counterweight on, and I've got to get out of the dolly somehow, and I've got to get on the mats to put on weights, so we do what we do....
 

skyking1

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you present scenarios where that is true. I have been able to do the other thing because they were new construction sites and we could at the very least have anyone's attention. I think reaching over a neighbor's occupied house to pick trees is dumb. Maybe i'm not cut out for the rental business.
I also don't consider where I could reach if it tipped over as 'under the boom' . I am talking about that space between me and the load under control.
As far as setting steel plates with half outriggers unpinned, that is just practical. I've set my own steel off the wood pads too, then backed up onto the steel. I also don't ' air out " under the tires to do so.
 

CM1995

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When it starts to tip (getting really out of chart- or if it gets shock loaded etc.), the outrigger extension beam cylinders can't hold the pressure of the whole crane standing up on them, and the crane weight will just shove the outrigger beams in, especially if they aren't pinned.

In the pictures this will make it look like the beams weren't at full extension, but likely they were, but with the crane standing up on them, it will just shove them in.

That's what went through my mind when I saw the pic but don't know enough about cranes to comment. I wasn't aware of the locking pins in the outriggers but thought if that crane goes over the weight will blow the cylinders in the outriggers like crumpling a drinking straw.

Learned something new.
 
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crane operator

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I wasn't aware of the locking pins in the outriggers but thought if that crane goes over the weight will blow the cylinders in the outriggers like crumpling a drinking straw.

None of the older domestic cranes have the locking pins. Its mostly a european thing, but my newest 40 ton grove truck crane has them just for the 1/2 outrigger position. Some of the newer domestic rough terrain and truck cranes have them, also for the 1/2 outrigger position, because you don't have the same amount of friction pressure on 1/2 outriggers to hold them out.
 

Natman

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A lot of the boom trucks have the pins for the halfway point on the outrigger beams also, the trick is remembering to pull them before trying to retract.

Crane accidents are right up there with plane accidents in grabbing the media and the public's attention. That's why I have yet to take a picture of me flying under the boom of my rig, though it would be safe and easy enough to do. A plane/crane accident combined would be national news!
 

skyking1

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Classic boom truck is boring that way. It is all or nothing. it makes for some long-winded setups, trying to get it all to fit.
rocktruck.jpg

IMG-20190215-132632.jpg
 
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