Monday, October 11, 2010
October 6th, 2010
Seoul Korea, I think that we have at least two cranes involved in an accident with two people dead. I have found video of the site, but it only leaves me with questions. The Video is slow to load at this site, but it will get there. This screenshot, at the top of the blog, is from another video that I couldn't get to load and it shows a crane that appears to have collapsed at the turntable. Assuming the timing of the videos are similar, and they are according to the dates loaded, it would seem that we must have had one crane collapse at the turntable, fell, and in the process struck the other tower crane boom.
The immediate reports are that this is a Comedil flat top crane and the Cat Head bolts are to blame. The suggestion according to the translation of the article is that the bolts should be periodically replaced. There seems to be questions about the type of bolt used and the manufacturing of them. Admittedly, this is from a terrible translation. You can read the article here.
I don't have a Comedil manual on hand to verify whether or not those Cat Head to Turntable bolts must be changed out each time. If they do, well, you should, obviously, change them out. The type of bolt that I'm used to seeing is of the same finish and visually appears to be the same material used in the tower bolts. I don't know if they are tightened to their yield, but I doubt it because they are tightened with a torque wrench if I'm not mistaken. Either way, follow the manufacturers plan on bolts and do not skimp on what bolts to purchase.
UPDATE: This is a copy from a translation of a Japanese story on the Korean Collapse. The short version -TLDR: Cat Head bolts were changed out to a smaller and weaker version. Link to story
Posted by Gaytor Rasmussen at 10:15 PM