Tuesday, December 29, 2009
Thursday, December 17, 2009
Update to the Hawaii self-erector tip story. News in Hawaii isn't what I'd call complete. I wouldn't characterize US news in general as good as it's based on popularity. I asked around and got the story. You might say that this is the rumor mill, but it's reliable.
Saturday, December 5, 2009
Dongguan City, China A Tower Crane from somewhere near the 50th floor of a planned 68 floor building. 3 people were killed with 5 injured. The story that I've found so far on it reports it as a "quality problem" with the crane already.
Wednesday, December 2, 2009
Warsaw Poland, The Poles are building a new National Football (read soccer in North America) Stadium in Warsaw. They have multiple cranes both Mobile and Tower throughout the job site. Yesterday two workers died when they fell 50 feet in a elevator car attached to the crane. Story
Thursday, November 26, 2009
Basel, Switzerland A Wolff tower crane jib, apparently being dismantled, was dropped due to stability problems with the mobile crane. The Tower crane jib will be a total loss, as well as the mobile crane boom and luffing jib. One woman was injured. It sounds as if she was in a room on the opposite side of the crane where a wall was destroyed in the impact.
Monday, November 23, 2009
Friday, October 23, 2009
The July 6th Liverpool tower crane collapse operator survived. A report is out from the BBC about his condition. Iain Gilham paralyzed from the waist down after having been thrown out of the crane as it was collapsing. Since then he's missed his daughters wedding and the death of his mother. He speaks on the BBC link on a video about the accident.
Friday, September 25, 2009
Thursday, September 24, 2009
Sunday, September 20, 2009
Monday, September 14, 2009
Sunday, August 9, 2009
Abu Dhabi A man fell from a 132 foot tall tower crane and the circumstances are suprising. A crane operator called an engineer crazy for a desicion being made about the project. The engineer took offense and climbed the crane to discipline the operator. He was angry at the time. I lead to an altercation and the operator struck the engineer with a steel bar. The engineer fell to his death.
Tuesday, July 28, 2009
Blue Cross/Blue Shield in Chicago was adding 24 floors onto their existing 33 story building downtown Chicago. The building was entirely being constructed out of structural steel sans concrete core. The hoisting was being done by two Potain MR605’s which are big luffing tower cranes. One of those cranes nearly came tumbling down from over 600 feet. Great decisions prevented that from happening. This is the story of the nearest miss I’ve ever seen. And I’ve seen a few.
The crane operator had an unloaded hook. He’s running the crane when he hears a loud bang and feels movement from what feels like the tower. He stops to assess what has caused it. The Bellevue crane that survived in the above story, Same thing. Unusual noise and shutter… stop and go see what that was. The crane that collapsed in Bellevue it happened during the crane erection, but we couldn’t get anyone to believe that it was a problem. I had an intermittent popping in a cross base once that wasn’t showing what the cause was. Eventually my ballast started spalling on the frame and cracks were developing in the concrete. We decided that it was torsional loading causing the base to flex. We called in an engineer to design a stiffening method and the problem went away. The commonality… stop and assess.
The towers are connected by pins. The upper section is hollow (with reinforcing) angles with holes milled to accept a set of pins, and from the tower below, a dowel of sorts also milled to accept the pins. It’s a tight positive connection. This dowel which cannot be viewed once the tower is connected is what failed. A crack caused a full separation in the leg connection. This crane was effectively three legged instead of four at this point. Private discussions that I’ve had with some that were there claim that engineers familiar with the equipment said that the engineering numbers showed that the crane should not be standing.
The crane was secured by welding a box frame to the outside of the tower leg. The project was nearly finished so the other tower crane was used to dismantle the nearly fallen tower crane within a few days. Since then all of these towers have had their connections reviewed and NDT tested at a cost to Manitowoc. The Technical Service Bulletin asks that pitting corrosion, cracking, and even scratches in the paint in this dowel area are cause for further review. This article has some decent pictures of what to look for.
So what caused the problem. There is a hypothesis that has been developed. The building was again made of structural steel. Structural steel flexes quite a bit. A job in Portland years ago had a Liebherr 630 tied into it’s structural steel building. In order to plumb the building, they had to balance out the crane first to remove it from pushing or pulling the entire building around. If you have two tower cranes tied into structural steel and don’t have all off the steel as rigid as possible, including diaphragm, then you raise the crane, and add more steel which you will make plumb and rigid, you are likely to add loading to the crane’s mast by pushing it around, and out of plumb. Additionally you have two cranes pushing that steel back and forth on each other adding loading that is unintended in the tower design. We may never know 100% why, as it could have had inclusions in the steel, Porosity, pitting, etc… we can only learn from the potential problem and seek to prevent it in the future.
I applaud the operator for his wise decision making. I’d name him, but I’m not sure that he wants that kind of attention. Dogging everything off and finding that problem was exactly the right answer. Potentially hundreds of lives were saved. To gasp the scope of this… the crane is 600 feet up with 160 feet or so of jib. The break is 20 meters of tower down. So if the crane fails entirely, you have about 250,000 lbs of steel and concrete coming down from 600 feet 230 feet long into a busy street an hitting occupied buildings. Locals 1 Ironworkers and Local 399 Operating Engineers proper training saved lives even though most never knew about it.
Sunday, July 19, 2009
A Self-Erecting Truck Tower Crane toppled this week in Switzerland. Storms and heavy rains were reported and the ground does appear to be wet. I also look at this photo and see poor soil conditions for setting up a crane. The ground clearly isn’t level, but I can only assume that the properly leveling of the crane was addressed. Something that simple isn’t happening is it? I wish that the picture was taken from a little further back so that we could see if there was good cribbing (dunnage, mats) or not.
It’s not often that we see Self-Erecting Truck Tower Cranes go over. They are a great piece of equipment, but the operators need to be aware of all of the same problems that come on both the tower cranes and truck cranes.There were no reports of injuries in this accident.
Oetwil, Switzerland A self-erecting tower crane that appears to have been well set up had tipped over while being used in a concrete pouring operation. !5 workers were on site but fortunately no one was injured.
The immediate thought given the clear stability of outriggers and number of counterweights is the limits. Is it that the limits were never tested or set up? Usually self-erectors limits are contained and once set up for the crane, they won’t need to be re-set unless the configuration of the crane is different. In Washington State the cranes are treated as tower cranes and the limits must be retested during each crane erection. Under the not yet released ASME B30.29 (new self-erector standard) the cranes also must be tested after each crane erection. Of course this is the US standard and even that is voluntary… at least until you have an attorney in a deposition asking you why you didn’t follow it as he stares at your wallet. Then it doesn’t feel so voluntary.
Self-erectors are a great tool, but they need to be operated by competent people. Running it rough and not catching loads near the limit can lead to problems. Imagine trying to run fast on an older crane. You are trolleying out and not paying attention to how heavy the load is or the load chart. From top trolley speed the over-turning moment limit goes off and stops the trolley instantly. The load has 60 feet of line out and now it just stopped at 100% of its capacity. The load swings out 20 more feet before stopping which is now at the toppling capacity due to dynamic loading. I personally think that this is the type of thing that causes most self-erectors to topple. Just an opinion.
Thursday, July 16, 2009
Chattanooga Tennesse. A 41 year old Tower crane operator suffered a medical emergency while in the crane. From 105 feet the fire department had to rescue the operator and lower him to the ground using a ladder truck with a man basket on it.
Something that we don’t talk about much on tower cranes is how to rescue operators, and sometimes others, when they suffer a medical emergency. On a tower crane 300 feet in the air it becomes difficult and time consuming for figure out on the fly. As an erector we always had long ropes for tag lines and if one of us were injured, we would get them down via rope immediately. It would violate everyone’s policy to do so, but sometimes common sense and Bureaucracy don’t mix. I’m gonna save someone’s life and worry about the consequences later.
Contractors should develop rescue plans and talk about it. Materials such as good climbing ropes, possibly a block, harness, carabineers, should be available. If you don’t have a rescue plan in place, you may find yourself with a man in trouble and a fire department trying to figure out how to get someone down as they are literally dying. In the US these emergencies happen 3 or 4 times a year. With some simple planning, this problem if figured out ahead of time might save a life.
Additionally, something that I’m an advocate of is Trauma Suspension Straps. If you fall into your harness and are waiting for the Fire Department to rescue you, you might be killed by your harness due to heart failure (low blood pressure) Worse, the blood that pools in your legs cannot circulate and if you hang for too long, the cells will have de-oxygenated and become poisonous. When you are taken out of your harness, you have the potential to die anyways. For guys like me working on my own, that’s a miserable prospect. The straps roll up in a small packet and remain on your harness. If needed you unzip the packet, connect the straps into a loop and they allow you to stand taking the pressure off of the leg straps allowing the blood to flow and preventing a heart attack or toxic blood. $20 might save your life one day.
Saturday, July 11, 2009
Monday, July 6, 2009
Liverpool, England A luffing (assumed to be a Wolffkran from the design) tower crane has collapsed backwards into a apartment building adjacent to the jobsite. The operator was thrown from the cab onto the building and is in stable condition. No one in the apartment or jobsite is reported to be injured other than the operator.
Possible reasons for this collapse are numerous off of the one picture. No limits on the boom allowing the boom to be taken past 86 degrees or so can cause this. Poor soil conditions giving way under a base can cause this. Structural failure in the tower would be obvious given more pictures. Shock loading due to poor rigging or load line failure also can cause loss of rear overturning moment.
The crane is an obvious loss. The project will be at a stand still. The apartment next door may have to be evacuated long term. We can’t say what the cause is from the one photo, but preventing it looks awfully cheap now.
Saturday, July 4, 2009
Melbourne, Australia. A crane hoisting drywall lost the load at about 15 stories causing a near miss accident. The load narrowly missing striking a car as you can see in the picture. The article isn't clear about how the accident happened outside of the claim that the load must have "snapped".
Monday, June 22, 2009
Graz, Austria Today's story does have a point, but it's more about the shenanigans of drunk students. In Austria this weekend a student walking home from the bar drunk decided that the tower crane was closer than his bed. He climbed the 150 of ladder and caught some sleep in the cab. As you can imagine it's not a healthy idea to climb ladders 150 feet up while drunk. So drunk that you don't even remember it. But all's well that ends well. The crane operator found him sleeping in the cab the next morning. I'm sure that a good laugh was had by all.
Thursday, June 18, 2009
Montreal, Quebec A story from last year about an erector death left me a little confused. A gentleman has pointed me to a link that helps clear it up. It's a report by the government as to how the accident happened. They have video animations which I will link to here.
Monday, June 15, 2009
Saturday, June 13, 2009
انهيار رافعة برجية
Monday, June 8, 2009
Malta is one of the smallest nations on the planet. With a population of 410,000, It’s smaller than most major cities. Just off the coast of Italy there is something this tiny island nation is having no shortage of this year, tower crane accidents.
On February of this year Malta had their first tower crane accident that I knew of. It was a self-erector that collapsed without a specified cause. Two weeks ago (May 20th) they had a second tipping, again from an unspecified cause. This weekend the crane that fell on the 20th was being replaced. During the crane erection either a rigging failure or pendant failure occurred and the piece being hoisted into place was damaged. There are no reports of injuries.
I don’t think that I quite understand the lacksidasical attitude towards safety after the first accident. Wouldn’t you have a master rigger there and expect them to inspect the rigging? If it were a pendant failure, did you really decide against bringing in a crane inspector? Don’t you want an honest 3rd party opinion as virtually all manufacturers suggest?
I can’t imagine that Maltans are going to put up with this. There were articles speaking out against the problem after the 2nd accident, so certainly the rhetoric will only become louder as 3 accidents in 4 months on an island of 410,000 people is ignorance on display.
(Picture is of May 20th Accident)
Thursday, June 4, 2009
Tuesday, June 2, 2009
In Dallas Texas yesterday there was yet another crane accident.Link . I normally don’t have much to say about mobile crane accidents, but this is becoming egregious and obvious as to what the problem is down there. If you look at the last year in Dallas, I can point to six accidents causing injury and making the news. How many didn’t make it on my radar?
The cause of four of the incidents is quite simply lack of inspections. The Dallas accident yesterday was due to a lattice boom rope failure (1 injured). The Huston Oil Refinery 2500 ton crane had allegedly the wrong bolts in the turntable (4 dead). A Tower crane operator wasn’t paying attention and the hoist limits had failed. As a result the crane two-blocked, parted the load line, and the block landed on a concrete truck driver. (1 dead). At Dallas Stadium a boom rope parted while attempting to lift the boom off the ground (3 injured). The other two accidents that come to mind are over turning accidents (3 injured). Save the over turning problems, the other 4 accidents are clearly preventable with inspections.
In May of 2008 I was contacted by the Dallas Fire Department Fire Prevention Officer. We discussed the possibility of me performing inspections on tower cranes and teaching them how to do it to protect the Dallas citizens. The follow up phone call was a disappointment to us both. The City had balked at the idea. The following month three of these accidents happened in one week.
Counting the dollars is a ridiculous way to decide safety measures. Many large entities argue that inspections and operator regulation are not necessary. ABC represents contractors all over the US. C-DAC (Cranes and Derricks Advisory Committee) is a proposal by OSHA to begin crane inspections as a compulsory item. Robert Hirsch, Director of Legal and Regulatory Affairs for ABC spoke before OSHA about C-DAC. His intention was not in support of protecting the long-term bottom line and or safety of workers, but rather he had this to say “…and to eliminate, or at the least significantly lessen, burdens that the proposed rule would otherwise needlessly impose.” Inspection to the standards laid out by the manufacturer should not be a decision that is hard to support. The manufacturer has their reason for wanting things done and it should be done, period.
The bottom line is not money. The bottom line is life. If the construction industry in the U.S. cannot safely hoist, or even choose to inspect cranes after six accidents in one state in one year, then OSHA is charged with the responsibility of stepping in and changing the practices of the industry. I may not be impartial since I am a crane inspector, but maybe right-to-work states such as Texas should look to California and Canada to see what the benefits of inspection and a skilled work force are? Maybe if you compared the cost of inspection and repair to the cost of lawsuits it would be a clear no brainer?