Crane flips, operator bails out

[Rock knocker]

I was the rig foreman who got to work with the diver to pick this 18-ton hydraulic crane out of 120-feet of water. It was setting on the bridge deck where the two guys are standing.

How'd they manage to dump the rig? I don't remember hearing any skittle-butt, which is funny considering where you were.

Link HSP's belong on the bottom of the ocean.

 

[Shield Arc]

How'd they manage to dump the rig? I don't remember hearing any skittle-butt, which is funny considering where you were.

Link HSP's belong on the bottom of the ocean.

That was on the 3rd Lake Bridge. On the Mercer Island side, I was on the Seattle side when it happened. I had to pick anchors before daylight the next morning and move into position, and make the pick at daylight so the local news would not show up!
I was told an apprentice operator was running the crane. Had a skip box on the hook, boomed out flat holding the skip box while labors filled it with dried concrete over flow. I was on a different radio channel, but was told, the kid running the crane radioed the labor foreman and said "hey I think I'm getting a little light". The labor foreman replied "just a little more".

 

[Rock knocker]

That was on the 3rd Lake Bridge. On the Mercer Island side, I was on the Seattle side when it happened. I had to pick anchors before daylight the next morning and move into position, and make the pick at daylight so the local news would not show up!
I was told an apprentice operator was running the crane. Had a skip box on the hook, boomed out flat holding the skip box while labors filled it with dried concrete over flow. I was on a different radio channel, but was told, the kid running the crane radioed the labor foreman and said "hey I think I'm getting a little light". The labor foreman replied "just a little more".

That explains it. There would have been a field day for the media, just like it was a little later ( I assume ) when the bridge went down.

 

[roadhunter]

Wow. That was horrible. If they couldn't get the dozer down there without a crane how in the world will they ever get all that equipment back up. Seems they now have to build a road to get down there.

Amamzing how fast it can hit the fan.

MoKelly

Get a bigger crane.

 

[Rock knocker]

Get a bigger crane.

Yup, that's normally how they do it.

 

[Shield Arc]

That explains it. There would have been a field day for the media, just like it was a little later ( I assume ) when the bridge went down.

That was the LVM Bridge, just south of the 3rd Lake Bridge. I thought it was funny watching the LVM Bridge sink on TV:laughing:. Until about 10:00 that night when the telephone rang:shocked:. I was told to get out to the bridge and start setting temporary anchors to secure the 3rd Lake Bridge. When the LVM Bridge went down it cut 13-anchor wires on the 3rd Lake bridge. My company hired every available tractor tug in Puget Sound to push on the 3rd Lake bridge to try and save it. Then later we got the contract to build the replacement for the LVM Bridge.

 

[orezok]

:smiley_aafz::thumbdown:Actually completely and utterly wrong :laughing:. Working off the rear of a truck crane is your strongest configuration because you have the cab and engine up front acting as additional counterweight. On RT's, you are most stable over the front because they have the engine in the rear. Lifting over the back is safest on TC's, boom trucks and AT's.:mur:

I would have to disagree with the "counterweight" theory. While the cab and engine will act as a counterweight, the long moment arm of the front of the crane far exceeds the counterweight effect. It becomes a very long stabilizer and is far better at resisting overturning.

In other words you have to push the cab into the ground to overturn it just as you would have to push a stabilizer into the ground on a side lift.

 

[Rock knocker]

I would have to disagree with the "counterweight" theory. While the cab and engine will act as a counterweight, the long moment arm of the front of the crane far exceeds the counterweight effect. It becomes a very long stabilizer and is far better at resisting overturning.

In other words you have to push the cab into the ground to overturn it just as you would have to push a stabilizer into the ground on a side lift.

Are you an operator? Talk to an operator, thats not the way it works generally. Here is a load chart for a small boom truck. The chart is unrestricted except for when operating over the front.

http://www.rhodescrane.com/assets/rhodescrane/file/equipment/load-chart-28-ton-manitex-2892s.pdf

 

[Rock knocker]

An article of pertinence. While this is for RT's, it is applicable in that it demonstrate that cranes are most stable when operating opposite the engine, over the rear for boom trucks and truck cranes, over the front for all RT's I am aware of

How to Keep an RT Crane on Its Wheels | Construction Equipment

 

[aczlan]

Are you an operator? Talk to an operator, thats not the way it works generally. Here is a load chart for a small boom truck. The chart is unrestricted except for when operating over the front.
http://www.rhodescrane.com/assets/rhodescrane/file/equipment/load-chart-28-ton-manitex-2892s.pdf

Can you point me to the page that shows this restriction? The only one I see is on page 8 which says "The front tires must be on the ground when operating on this area" that makes sense as it provides a longer lever that has to be moved before the crane can tip and the front outriggers are behind the cab.

Aaron Z