19.08.2011

Lifting in the structural zone

Most crane load charts are split into structural and stability sectors, when overloading in the stability are we know what happens the crane tips. When overloading in the structural part, only the design engineers have any idea what will fail first.

The following photos were sent to us from Central America but look as though they came from somewhere in the Middle East. We know that the incident occurred at the end of July, but not much else.
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It seems that the crane lifted a heavy load off the truck

Looking at the photo graph it looks as though the crane was offloading a container or other load from the truck. The Tadano Rough Terrain crane has clearly been moved in as close as possible to the load and must have lifted it well clear on a half extended main boom at full elevation.

It then seems that the load was excessive and something had to give- in this case the boom lift cylinder where the rod buckled in a manner we have not seen before.
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The lift cylinder buckled

Overloading used to be a fairly common occurrence – and clearly still goes on - however do it in the structural area of the chart at your peril. In this case the issue has been highlighted immediately – although this might not have been the first time this job was carried out? More frequently the damage is not self-evident and only shows up at a later date, when the crane might be carrying out a relatively small load well within the cranes load chart.