Monday, December 27, 2010

April 30th, 2009

Chernvtsi, Ukraine A small self erecting tower crane suffered what appears to be a structural failure during the dismantling process killing a man. These old self-erectors often dropped the jib tip of the crane to the ground then maneuvered the mast down and eventually the jib would be stored horizontally. In this one we see what appears to be a fresh structural failure. I don't know if it was the cause of the accident or a result. But what is clear is that some of the best practices aren't being observed in the maintenance of this crane.

You can see the clean gray steel that appears to have ripped and or fractured. The top appears to have a fractured drop forged piece of steel on what I assume is a top chord. 

On this picture it's clear at the red arrow that the dead leg and the live leg are clamped together. This severely weakens the ability of the load line to sustain the load. If you look at the blue arrow, you'll see that it's pointing at a wedge and socket on the opposite side and it appears to be loose. I don't have enough details to see if that's due to a broken line or due to a luffing drum failure. Either way, this isn't the right way to do it. Add a slug of wire to the dead leg. Add enough length to the dead end to clamp it back to itself which would prevent it from being able to run. Or, even better, use a Crosby Terminator which takes most of the work out of the issue. Just maintain the cranes properly. 

If you speak Russian, there is a lengthy News story here that might get more of the story out for you. If you want the original link, here it is

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