Thursday, December 9, 2010
December 12th, 2008
Lindenthal, Germany (suburb of Cologne). Two Tower crane erectors suffered leg injuries that were described as severe and were taken to the hospital. Looking at the pictures, I can almost promise that it's broken legs, and lets get to why.
In the picture we have a crane boom that has been set down on the ground. The journalist isn't sure if this crane was going up, down or was dropped. I would suggest that this boom was set on the ground that was uneven. Even at this point, it still looks like it's not all of the way down on the ground on the sidewalk.
The lower chord pin at the Red Arrow appears to have been removed while the jib was partially airborne with the jib touching at each end. The jib is under tremendous stress at this point. Either the jib should remain suspended by crane while only the lower chord pins beyond the rigging points are removed, or the jib should be set down on dunnage (wood) to support the jib at either side of each splice. If you have wood under each sectional connection, you can safely remove the pins. But even then, there are two measures the erector should do to protect themselves, and I don't think that they did either.
First, when you are removing these lower chord pins, stand on the lower chord. If you have your feet planted on the ground and the jib shifts violently, you become the target. If you are standing on the lower chords, you go for a bit of a ride and might end up smirking due to surprise only. The second thing is the hammers used. Yes, hammers, plural. Don't just use a sledge alone. When the pin gets close being ready to be driven out, if there is any tension on it, you should use a B&O (backing out) Hammer. With one hand hold the snout on the pin. With the second hand you swing the larger sledge on to the face of the B&O. The long snout protects the hole from being marred by strikes. Additionally, when the pin frees, the snout will follow through. This will prevent the radical shift of the piece. When you are dismantling, this tool is incredibly useful, especially in the air.
A quick story, a rookie Iron Worker was with myself and another journeyman. We set a jib down on uneven ground. We had a second (assist) crane so we were going to pull the pins after we had the jib supported by the second crane. I'm off disconnecting the fall protection. Keith is bending keepers so that we can move quickly when we start to work with the crane. The Apprentice starts to drive the pins at a point where there is significant clearance between the ground and the lower chord. I walk by and say, "Hey, get up on that jib. Your feet are in the bite." He gets in the right spot and I walk away. He's swinging away at this pin and it isn't moving well. He puts his feet back on the ground and Keith see's it. "Hey, didn't Gaytor just tell you to stand on the lower chord?" He gets back to where we told him to be. He swings a couple of times and again puts his feet on the ground. The pin comes free, the jib shifts down and breaks one of his feet. Sigh... In the US we have a saying, "You can lead a horse to water, but you can't make him drink" He's a nice guy, but he was one of those young Iron Workers who is the son of an Iron Worker so somehow he knew best through his genes.
Stand on that lower chord, support the jib, use a B&O and you'll never have broken bones in your legs and feet from a loaded jib.
Turmdrehkran Demontage Unfall
Posted by Gaytor Rasmussen at 10:45 PM