January 25th, 2009

Bern, Switzerland. A man working around a Self-Erecting Tower Crane was killed when it "slipped" off to the side. He was killed in the accident.

The information shown doesn't give any clear indications as to potential causes. There is only on brief moment in the news story that seems to show the crane with out riggers folded out as if it were sitting on the outriggers. It's clear that there is considerable snow in the area. As a point of consideration in these scenarios, if you are going to set up over snow, you'll want a shovel. You should not be setting up metal outriggers on snow or even frozen ground. It's important to use wood in these cases. The reason it's important is not for compression, but rather torsion. A metal outrigger on frozen ground will have little resistance to slipping if the ground is not level, or sliding if the crane is slewed. There are torsional resistance requirements on cranes. It's rare that this becomes a problem, but this is a case where it may have been a concern that should have been heeded. So at the time of year when Europe and North America are covered in the white stuff, make sure you take the extra 5 minutes to remove the snow whether it's on a Tower Crane on pads or a Mobile. Do this both under the pads and or under the matting used.

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