On Fri, 21 Nov 2014 09:09:04 -0500, "Pete C."
wrote:


Ignoramus11173 wrote:

On 2014-11-21, Pete C. wrote:

Ignoramus11173 wrote:

Scary situation.

http://www.machinerymoverschicago.com/blog/Crane-Fail/

Wow! It's difficult to tell from the perspective in the picture, but it
looks to me like the crane was set excessively far away from the lift
point and had the boom at too shallow an angle, looking 45 degrees or
so.

[I added one more picture]

Yes, I agree with that. It was a risky lift and somehow or other, it
was riskier than they thought.

A couple years ago I got to play with a 60T Grove moving 40' containers
and we had it setup only about 40' from the crane boom pivot point to
the lift point and the boom extended to give probably a 60 degree angle
with loads of around 12,000# for a container and a small amount of
contents.

I would have expected that commercial crane services , like that one,
should have load moment indicators and other tools to prevent such
incidents.

i

Those cranes do have computers monitoring and giving warning alarms, but
it's still possible for things to go bad too fast to react or to
miscalculate your load. If the computer gave them a load rating based on
the boom angle that was just a bit over the presumed weight of the tank,
and the tank snagged and added extra load mid lift it could well have
been all over by the time the operator recognized the alarm.

I worked on German made Tower Cranes with horizontal booms, twenty
years ago, that had a load limiting device on them. They wouldn't
pick up a load that was too heavy for them and if you picked a load up
close to the tower and tried to move it out the boom to a position
where the load was too heavy for the crane the in/out function stopped
any further outward movement.

I was told by the crane operator that this feature was common on tower
cranes.
--
cheers,

John D.Slocomb