Wednesday, December 1, 2010

August 1st, 2010

Harbin, China. A Tower Crane being climbed in Harbin China collapsed after being erected. I don't have any details on the number of people injured or dead as the video is the only source that I have found on this. The link to the original video doesn't have an exact date on it and only lists it as about 4 months ago. So that date listed is just an approximate.

The tower sections are short, and so is the climber. Clearly the climber is broken, but likely that's from the side loading once the collapse began. What strikes me when I look at the tower sections that were bent is that even though they are short, only two are broken. Does this climber only reach down 12 feet or so? Does that allow the spread of the load across enough surface of the tower sections? Does that allow for enough ductility in the structure of the climber itself? Is this a design problem? The quality of Chinese steel is under question to begin with.

In terms of practice, the crane appears to have gone over to the side. So was the tower properly plumbed to 1:500? Was there wind at the time of the accident? It's noticeably calm during the report so that doesn't strike me as likely. Given that there is little twist in the tower, I wouldn't expect that the crane wasn't slewed off kilter. The only other thing that strikes me as a potential is the human error of running the climber over the top of the tower. Often there isn't a terrible amount of play given here, and if you went past the mid rollers, this would be a likely result. Original Link 

中國哈爾濱, 塔式起重機倒塌, 塔式起重機事故

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