I have been contacted about a Tower crane accident from January of this year that occurred in Worsley Australia. Somewhere in my research I had attributed it to Yarwun Australia. Both locations have aluminum refineries and so it's an important detail that I have either researched incorrectly or reposted from the media incorrectly. Either way, please note the correction.
Wednesday, March 17, 2010
Singapore, A tower crane collapsed today killing one 32 year old worker and injuring three others. The crane was being dismantled at the time.
The story describes the collapse of the boom. The included picture shows a turntable that separated from the mast. You can see the pin holes with no pins in place. I'm wondering where they are. Two possibilities come to mind. The crane was being climbed down and the climber was not attached to the turntable. If it were they (the climber) almost invariably come with the turntable. I don't see structure or pins there so they assumption of a climbing operation explaining the missing pins doesn't ring true. Is it possible that the pins from the turntable to the mast were removed before all of the horizontal was removed? I can't imagine why and can only point to one potential cause... The workers taken to the hospital included a Thai, Chinese, and Bangladeshi. They were working in Singapore. What language did they use? How well did they communicate amongst each other?
When I see these stories of multi-national teams working on tower canes I shudder to think of the dangers of not understanding each other. I don't have nearly enough information to determine the cause of this accident. What I can say is that I wouldn't work on a crane where everyone didn't speak English. If I was the odd man out, fine. It's the safer choice.
I worked in Hawaii 3-7 days a month for 4 years. The challenge of speaking the same language with vast accent differences was tough enough, not to mention the difference in phrasing. Eventually it became normal, but it was a learning curve. To take that to another language, I can't see any good coming from that. No matter what country you are from, think of how hard it is to understand a foreigner who speaks the same language in a quiet room. Now stand 40 feet apart on a noisy construction site and explain what pins to remove and which ones not to? That has disaster written all over it.
Edit Pictures have come out overnight that show a climber resting near the top of the tower. It doesn't answer many questions, but it's certainly a point of interest and raises more questions.
The first image is from Images by XiaoFanSu aka Sapphire, via Punggol.org
Posted by Gaytor Rasmussen at 7:55 PM
Sunday, March 14, 2010
Atlantic City, New Jersey A tower crane collapsed on the Revel Casino project during high winds. The cranes on the project appear to be Potain 485's as of November there were six on site and it is't clear as to how many are currently on site. The job appears to be wrapping up and the visibility of the cranes is poor in the news stories. It's clear that there are two cranes still on the high rise even though one of them now simply consists of the mast of the crane. It would appear that the entire super structure was ripped off the crane.
The winds were severe enough to take down two houses during gusts. I haven't been able to find what kind of gusting there was at 500 feet yet, but on the ground, taking out two houses is pretty severe. A local firefighter that was interviewed noted that it was the worst wind storm he had ever seen.
The collapse appears to have damaged enough of the building that debris was flying up to six blocks away. A police officer was struck by debris inside his cruiser and was taken to the hospital.
When erecting cranes you do need to consider what the winds in the area are like. If you are in Florida where hurricanes come every few years, it might not be a good idea to erect a max free standing crane to 300 feet even with the larger bases. Wind speeds climb quickly as you gain in elevation. The added surface area lends to the winds ability to push the crane around, plus it adds leverage in the winds favor in terms of the over turning moment. In this particular case, it may be that the accident was virtually unavoidable and simply caused by nature.
Posted by Gaytor Rasmussen at 12:14 PM
Thursday, March 11, 2010
Pretoria, South Africa A truck travelling down the N1 highway lost control slamming into four cars and a tower crane that was erected in what appears to be the median between the two directions. It was assisting in the building of a bridge. One report says that the crane was moved over a meter with the supports damaged. Looking at the picture the crane is clearly out of plumb but still standing which is a testament to the cruciform base design that it is sitting on.
The base is ballasted with knee braces running up to the first tower. The concrete ballast generally sits on the steel beams that support the tower without much to secure it. Under normal circumstances there is little to no movement at this point on the crane so it's rare that the weights would be subjected to movement. The shock of the truck hitting the crane hard enough to move it and knock it out of plumb could have easily knocked off the ballast and then there would be little chance of the crane remaining vertical.
The crane was dismantled and they will start over with a new crane to protect the public. The only lesson to take away is think of the worst case scenario and maybe build a reinforced concrete wall around the crane when it is exposed to traffic. This happened one other time, to my knowledge, in 2007 when a car hit a concrete pedestal that a crane was sitting on. The engineers whom designed this crane, the pad, and otherwise, did an outstanding job and this is why the crane stood possibly saving multiple lives as traffic would have been careening towards a falling crane with no where to go.
Posted by Gaytor Rasmussen at 7:33 AM
Saturday, March 6, 2010
James Lomma is set to turn himself in and face Manslaughter charges. He is the owner of New York Crane which had the Kodiak Tower Crane that collapsed on 91st Street.
I've told the back story before, so i'll be brief. The crane was taken down in an emergency just under two years before the collapse. The Oiler on the crane was lubing the crane in the turntable when he saw daylight coming through the tub at the flange that transitions between the round tub and the bearing connection. I'm told that this connection on those old Kodiaks was 3 inches thick, so daylight should normally have difficulty in penetrating this.
After the crane was dismantled the shopping began. A Ohio company bid $120,000 + compared to $20,000 bid by a Chinese company. When the Chinese company got a better understanding of what it is they needed to do they tried to decline the work but some how, they were convinced that they could to the work . Less than a year after the crane went back up, it collapsed killing two men, stopping a job, taking out multiple apartments, etc.
The other part of the story is that the man whom approved the repairs from the city was a former employee of New York Crane. The previous head of the Department of Buildings Crane Division was concerned about the repair as she left. She started an email chain that ended with a former employee accepting the repair. I would suggest that it would be a good practice for the Department of Buildings to have their employees recuse themselves from any case where impartiality might come into question. It may not have made a difference here, but it's good practice.
I'm not for people going to jail for mistakes. Much of the talk in the crane world is that there was some crane grease thrown out to get the repair company to perform the work. If this is what the prosecutors are finding, I'm all for prosecution. We have a responsibility to ensure the safety of our equipment for the general public and the users. If the crane was not going to be able to be made safe in a cost effective manner, then it's 24 years of service should have been the end of the crane's service life and the death of these two men is no accident. Time will ferret out the truth.
New York Times Full Story
Posted by Gaytor Rasmussen at 6:08 AM