Saturday, June 21, 2008
Wednesday, June 18, 2008
Sunday, June 15, 2008
In all of this there is one good thing to report... there was a school bus crushed with the driver inside being one of the fatalities. Fortunately this was not a loaded school bus.
As a result California has been inspecting their cranes since the early 90's. Their crane fatalies have dropped dramatically and I am not aware of another collapse in California since then. Inspection will not catch everything, but as California shows, it will reduce deaths.
If anyone can find any pictures of this accident I'd be very interested in seeing them as I have never found one.
věžový jeřáb kolaps, věžový jeřáb nehoda
Heavy winds down a Potain in Prague. I wish that I spoke more Czech but I'm not sure if there were any injuries and cannot find references in English. When you see that you can find them in a country like Czech not being reported outside the borders because it isn't important, how many are we really not finding?
věžový jeřáb nehoda, věžový jeřáb kolaps
The date is what is listed on the camera. I'm having difficulty finding stills of this accident.
A self erector was hoisting a water tank into place when the ground pressures became too much for the soil. The tank and crane fall taking three men with it. It sounds as though two men survive it and two die. The website is a Czech website and Pad Jerabu means falling crane. It was caught on video and took place in New Providence Iowa as best I can tell.
Tracy Roth, 29, of Cottage Grove, was on a five-member J.H. Findorff and Son crew that successfully erected the vertical sections of a crane at an addition to the Sandburg Hall dormitory.
But at 2:50 p.m., Roth was assembling horizontal sections 220 feet off the ground when part of the crane apparently struck him in the chest, said Richard Lynch, Findorff executive vice president.
The accident occurred so quietly that many people near the work site only learned of it later. ``There was no physical damage to the machine, no property ...
You have to know how to stay clear of pinch points. This iron worker may have been good most of the time, but a sad misplacement of his body got him crushed. When you have a 30,000 lbs jib coming at you we want to stop it from hitting the crane too hard, but always know your escape route!
Thursday, June 12, 2008
Check your hoist lines daily.
Friday, June 6, 2008
In the video and other videos you'll hear people state that it has to spin in the wind. It has to be able to move with the direction of the wind. I don't see a tornado over head and this is not what spinning with the wind means. The tower is being worked excessively hard while the crane is spinning that fast. The crane itself cannot swing that fast so the moment load kps are growing beyond intended loads. The grease in the motors and Rotec are low rpm. So you start spinning at 5 times the rated speed and heat will generate. If a motor or bearing were to seize due to over use like this, that crane would dismount like a gymnast on a pommel horse.
A cure is to let the swing brakes drag a bit to prevent this from happening again. If the crane can vane before 40 mph it's better than letting it tear itself apart. This is just like anyone who's tit is about to be in a ringer... nope, everything is just fine here. this happens all of the time, you've just never seen it. Shenanigans!
Edit: I found a link while searching for new accidents in Arabic. The crane collapsed either during the dismantle or during a climbing operation. The translation leaves much to desire -"we do unzip the tower crane, which weighs 140 tons and the final phase of the jaw upset their balance and fell on us" said one of the injured workers. You can clearly see the climber is on the crane and the article notes that people had to be present above. When he mentions an upset balance, and I see the jib in the picture of the downed crane, I picture this being a climbing operation.
New picture found
I've found information on the accident recently due to Google improvements. The crane was an inverted jib, which makes me read, old crane. Krolls and Lindens were known for having the inverted jib. The crane was a total loss as it came down and injured six people. The jib was strewn across the street having crashed into motorcycles and over the building that it was working on. Additionally it took out the power lines in the area which must have been a mess because like many developing countries the poles have a plethora of lines on them.
The crane itself was 100 meters tall with 45 meters of boom. It was working on getting at least 22 stories on the building. It sounds as if the building was scheduled to open in the Spring of 2008. Link
Suspected metal fatigue may have caused this jib failure. Micro cracking is a condition that can only be seen with the naked eye while the crane is loaded.
The problem with some of the older cranes is the steel as flexed so much that it developed stress cracking. It's hard to tell the difference between a stress crack and metallic cracking. as a result and due to the liabilities of construction, I personally don't like cranes over 20 years old.
Think about how close this was for the operator in terms of being struck by that jib and possibly having the cab ripped off the crane.
Another operator fell in Wyoming within months of this accident due to ice. The Wyoming operator lived because the crane had fall protection in place since the crane had a vertical ladder.
For one reason or another this crane was ready to be climbed. Tower cranes have back moment (they weight more in the back then the front) so in order to be climbed they must be balanced. You can guess pretty closely at the balance point of a crane. Since you are supposed to pin or bolt the climber off to positively attach the crane to the climber, you only have to be in the ball park. These idiots didn't connect the climber to the superstructure and removed the bolts from the mast to the superstructure. The result is a beautiful dismount fortunately not killing anyone.
Fortunately a gentleman caught in on camera and you can see it here.
In the Middle East right now there is so much growth that a large portion of the workers come from the Philipines or India. Much like say a Russian or Mexican crew here in the US, you end up with language barriers and an inability to teach people proper safety practices. From what is reported and the number of cranes there, they have a stellar safety record in that area. But we have to make sure that people don't take chances because of a language barrier. The life lost might not be the dumbass's, it might be yours.
The climbing section fell hitting collar below that was holding the crane to the building. The collar failed to support it's new load and the climber continured to fall to the next collar which stopped the fall. Sadly the father of the team not being tied off fell to his death.
Dismantling a collar can naturally be an impressive shock to the crane. I can only imagine how a instant removal would react and then to have the crane above it's max free standing height... Miami is fortunate that this crane did not fall from 400 feet plus.
As is the normal course of action, attorney's have valuable information about this buried and we'll only get to guess about how to learn from it. I stopped riding climbers down after this accident. In hindsight, it's illegal anyways.
Second crane with man basket? Relieve pressure and use a proper tool to get clearance such as a sleever bar? I wasn't there but I can't imagine that there wasn't a less cowboy way to acomplish this task.
The researcher may have fallen while in a man basket and operating the crane via remoted control. He should not have been alone and that policy must be adhered to.
Luffing tower cranes must be boomed down to a specific radius given it's configuration to allow it to weather vane. If it is not then if pointed into the wind, the jib can literally be blown over backwards. This happens all to often and later I'll link a video of a crane here in Seattle swinging around rapidly. The claim is that it was working perfectly fine, but it was the shenanigans of nothing to see here, move along. I'll get into that in that story later.