Monday, June 22, 2009

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.

In Seattle there is an unnamed operator whom years ago went out drinking with the Ironworkers on the jobsite. (First lesson, don't go drinking with Ironworkers.) Rather than driving home just to have to come back, he decided to climb up to sleep in his crane. Someone noticed him in the cab and called the police. He awoke to his phone ringing and laser pointers on his chest from the SWAT team which is a whole other political topic. Virtually all of us who know give him a bad time about it everytime we see him. His phone was ringing because the contractor wanted to know something about getting up there. "Uh... It's me up here. I'll be down in a minute."

I had a crane in the University of Washington area. The first week of school I came in on a Monday to find the crane hook in the middle of the tree near street level. It's likely that on Friday or Saturday night someone got into the crane and was playing around. Leaving the hook down, dangerous for everyone, but the person had trolleyed out far enough that the hook was hung up in a tree preventing it from swinging into the street.

The lesson is that we should secure our cranes. Many cranes have locks on the hatch or door. If they are utilized you are less likely to have protestors reach the top of your crane and turn it into a billboard. We put a lock on my crane. It was a small tower crane so if it had gotten onto the street, a passing bus could have easily pulled it over. Just make sure that you don't add windloading to the tower with your method of blocking access to the tower if that's the route that you go. Oh, and don't turn your crane into a drunken motel. Sleep in your car if you have to.

Thursday, June 18, 2009

June 16th, 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.
The crane shown is a Piener 405 or 415. The crane was being disassembled. They were taking off the outer jib when it shifted, coming back and striking the erector in the head and pinned him to the top chord of the jib. You have to imagine that this piece weighs possibly 30,000 lbs, depending on length. The jibs rarely come in level, and often you don't want them to. You want to be able to make one connection, adjust the piece and make the next connection as it's easier to make a double connection, or single connection then allow the metal or gravity do the rest of the lining up.
During disassembly it's the same process in reverse. The jib is not coming out level. The crew that I worked on would hoist the piece sometimes mutiple times until we liked how it was positioned just off of the ground. Then we would paint mark the rigging locations and note, 10 feet tip heavy, or 10 feet "butt heavy" (flattering term, no?). The intention was that the dissasembly crew could visualize how this jib is going to free up and know that the rigging points are correct.
In the computer animation here, and here, you see the jib come up and strike the man. Note how the jib moves out then comes back and hits him. Here's how that happens on a Piener. That connection at the top of the lower chords has some flat bar that extends over the connection. So the male connection from the outer jib has a little area where it could hang up if the mobile crane is under-boomed. The jib is horizontal (nuetral) instead of tip heavy. As the guys get the piece free, it shifts nearly instandly and since the crane was under-boomed itcame back and hit the worker.
My suggestions are the same as my first blog, plus some more. #1, Use a B&O (Backing Out) hammer to drive pins on tower crane jibs. #2, after the pins are removed and before the B&O is removed, a sleever bar or Spud wrench needs to be in the hole to control the load. You move the mobile until the piece floats and you do not remove that tool until it floats, period. #3, the Mobile crane operator should be aware, or the "phone man" in the air should ask if the crane is under or over boomed if questions arise. Fianlly, #4 Mark you jib pick points and the attitude at which the peice flys naturally using those pick points. As a back up a guy can take a 15 foot rope, tie the horizontal members together by looping the rope twice, then twist the free ends until it is snug. If the piece jumps then the person can start to loosen the twist and manually float the piece. You'd be surprised how effective this is.
The report does not change the fact that this death was preventable. With a tool in the hole, the phone man should have seen that the piece was not moving, asked the ground man if it were over boomed, then boomed down until it pops free. At that point you adjust the hoist until it floats, pull the tools and the mobile crane now safely has the piece.
Crane work is unforgiving. If you think that you are on a crew that is unskilled, you probably are. If it takes you more than a day to put up the average crane, quit today. I see things travelling around to cities all over the US and simply shake my head. Someone on the site must know what they are doing, and they are incharge, period. Please, use the proper tools. Contact me if you don't know how to do it.
Thanks to the person whom sent me the link. Updates are part of what I'd like to get so that this blog is as accurate as possible. Journalists don't know what they are talking about in this arena and any solid info only makes us better, and safer.

Monday, June 15, 2009

May 21,2008

Atlanta, Georgia - I learned today of a tower crane accident that didn't make national news during the rash of accidents in the US last year. A Liebherr 420 was being prepared to be climbed on an Atlanta jobsite. The collar appears to have been installed and the climber mounted on the tower. During the process the climber freed up and fell 70 to 240 feet (conflicting reports) to the building below. If you go to this link and watch the vid you'll see the end of a strut sitting on floor as if the bolts were all sheared off at the splice plate. There was a person on board the climber during the fall and they managed to survive with multiple injuries.
The details are few and far between. Hopefully details will be released at some point so that we can all learn from the problem(s) that lead to this accident and prevent it from happening to us.

Saturday, June 13, 2009

May 16th, 2009

Amman Jordan On May 16th a tower crane collapsed while building the Jordan Gate Project. Working on the 44th floor at a reported 220 meters the horizontal superstructure suffered a massive failure. This weekend the crane is to be dismantled in a planned three day process.
As you might imagine, this dismantle is going to be tricky to say the least. The jib is folded in multiple directions and will require securing as the sections are cut free with a torch. Often these types of operations are done from the safety of a second personnel basket from a second crane. Given that this is 220 meters up, the logistics of setting up a ground crane with that much boom and a derrick are daunting. As a result it’s likely that just to get this down one guy is going to have to be on what remains of the crane to make the cuts. Shifting loads, bound loads releasing energy, and falling items are going to keep this man in peril throughout the operation. If there weren’t other buildings around it would be better to tie a rope to it and cut it down like a tree leaning the wrong way. Alas, we are never that lucky.
I haven’t found any reports as to a cause of this accident. Often when the jib of a crane collapses the counter jib stays put. As a guy who has installed and removed thousands of counterweights, that’s impressive. In this case it failed as would be intuitively expected. You could expect that there was a tower top failure, but the shock of a pendant failure on either jib might cause this as well. It’s impossible to narrow it down without further information.
It might be important to note that this job has suffered other problems. 3 stories collapsed killing 4 and injuring 15 in 2006. A fire on the eighth floor broke out in the same year but no injuries were reported. The current crane accident left no one physically injured (an operator survived this?) but an Egyptian man was treated for shock. The crane dismantle is expected to take three days. Day one might be over at the writing of this blog. My thoughts are with the men faced with this task.

انهيار رافعة برجية

Monday, June 8, 2009

June 5th, 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

June 4th, 2009

Tokyo, Japan a Luffing Tower Crane being climbed down for dismantle appears to have suffered a hydraulic failure in the climber that caused the boom to collapse killing a worker and person on the ground.
Often tower cranes are climbed down to allow for a smaller truck crane to either reach it or allow for using a smaller truck crane to perform the work which can save tremendous amounts of money. The climb is achieved via a climbing frame that surrounds the mast then connects to the turntable. It is connected to electrical power that runs a hydraulic pump that pushes a ram into climbing dogs (of various designs). The hydraulics are supposed to have check valves in case of hose or pump failure. The check valves should hold the ram in place during a hose change out if it were necessary. From the sound of the description I hear that the turntable fell, crashing hard into the tower below, while being climbed down. This could have been from one or two meters and would have been violent.
So what could have caused the climber to fail? Three causes come to mind. If the Check Valves were not in place or simply weren’t the right size, or the valves failed themselves. This could be the result during massive pump or hose failure. Stranger things have happened, but this would be a new scenario to me and I would want to see the maintenance records on that climber. Were the check valves ever changed out to possibly the wrong ones? The second stand out potential is the climbing dogs slipping. In many designs a person has to physically or mechanically pull the ram in to proper position. If a guy got lazy it could be off and a slip could happen allowing the crash. My third and final suggestion would be climbing dog failure. These structural members are welded into place just like any other piece of the crane. If you had a weld or metallurgical failure, again, this would be the result.
This is an odd scenario. I have 100+ crane accidents on my blog with maybe a dozen climbing accidents and no climber slips that led to this. In New York a tower was thrown off due to a slip, but the result was the tower being thrown off the platform and landing on a passing cab, not killing anyone, luckily. The solution there is to secure the tower to the climber via rigging while climbing. Past similar accident link.
Another possibility, from looking at the pictures, is that the tower crane came apart from the climber. The climbers are either pinned to the turntable, or bolted. This type of accident has happened twice that I know of, in Seattle in 1985 and in Croyden, England in 07. If you do not bolt or pin the turntable to the climber, only balance would hold the turntable on the climber. The idea that this could have happened again is beyond comprehension and murder charges would be the appropriate result. This is simple speculation in looking at the pictures and not based on the stories that I’m reading.
Hopefully we’ll hear the cause of this accident. Climbing a crane is some of the most relaxed work in tower cranes, if you have experience. It’s 15 minutes of fury followed by 30 minutes of trying to stay awake. But the guy running that pump needs to pay attention and every move that you make is critical. Sequencing and experience is critical even though it can seem so simple. The most spectacular accidents happen during climbs. This one may not even be human error, but you must have the right people in place for a climb. If you don’t… Seattle in 85, San Francisco in 89, Manhattan in 08, Hong Kong in 08, New York in 06, etc.


Tuesday, June 2, 2009

June 2nd, 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?

Monday, June 1, 2009

May 30th, 2009

New York, NY The problems that led to the collapse of the Kodiak tower crane last year are becoming clearer. A story out of the New York Daily News today discusses emails between the Chinese weld repair company and New York Cranes. Link None of it is surprising but well worth learning from and being sure that we are all doing the right things to protect ourselves, our clients, and the public.
The brief of the story is that the Kodiak Crane was taken down in Times Square in an emergency about a year prior to it's collapse. The 3 inch thick steel transition between the flat horizontal and the vertical round section in the turntable had cracked and when the area was tensioned by the back moment of the crane it allowed daylight through. It was noticed by the oiler, inspected by the city and promptly removed. This area of the crane is subjected to the most stress. It's under shear during slewing, tension or compression depending on load and jib position, and cyclical stresses as the crane unloads and/or stops it's slewing.
After the crane was taken down the shopping of prices to repair the weld began. Avon Bearings of Ohio bid $120,000 to repair the weld and a Chinese company RTR bid $21,710. New York Cranes chose to use RTR. The proper way to repair this weld is to remove the entire weld on the 8 foot in diameter turntable. The parent metals would have to be beveled, cleaned, inspected, possibly UT'd, held in place in a jig, and the metal pre-heated as the weld is laid in layer after layer. It's time consuming and expensive. More importantly it's one of those welds where you want that guy that takes his time gets 100% of the slag out of each pass and doesn't claim that he'll just "burn through it". A weld of this size and importance should have been UT'd as well. The real cost of not doing it right... life, your business, life savings, public embarrassment, Jail?
RTR apparently was concerned about the weld quality. It's been claimed in the Daily News Story that extra money was paid to ease RTR's concerns about the quality of their own welds. Even better the company's quality of workmanship was called into question a month prior to the collapse on another crane. The former Department of Buildings Chief Engineer called into question the weld repair on the Kodiak and the crane was allowed to continue to operate by her successor whom was a former employee of New York Cranes.Link
Recusal may have been the proper decision. Hell, simple requirement of 3rd party UT of the weld would have found the problem and 2 people would still be alive.
The cost of the weld repair may have seemed like the right business decision at the time, but Kodiak Cranes are now heading towards being worthless. Another one in New York was removed from a site and a Liebherr 540 was put up in it's place. Imagine the costs of the swap, re-engineering of the base and tie-ins, and you'll get the scope of the desire to have a Kodiak on site. Even if it cost a million, get it off my site was the attitude. New York Cranes will be lucky to survive this lawsuit and black eye. If anyone can do it, it's a New York construction company because the nepotism runs rampant. If the accusations of payoffs are true, James Lomma may find himself facing jail time. Heads have to roll after two deadly and high profile, and avoidable accidents in New York.
Take that extra step to be sure that you are doing everything properly. Even if it costs more in the beginning, this story is a great example of the costs of not doing things properly.