Crane collapses in Mecca (holy muslim city), 107 people killed

[ichudov]

http://www.nbcnews.com/news/world/least-107-dead-crane-collapse-meccas-grand-mosque-n425891

RIYADH, Saudi Arabia — A towering construction crane toppled over on Friday during a violent rainstorm in the Saudi city of Mecca, Islam's holiest site, crashing into the Grand Mosque and killing at least 107 people ahead of the start of the annual hajj pilgrimage later this month.

There is a video there, too.

 

[ichudov]

Oddly enough, it happened on the anniversary of 9/11, celebrated by the attendees.

``The construction giant Saudi Binladin Group is leading the mosque expansion and also built the Abraj al-Bait project.

The Binladin family has been close to the ruling Al Saud family for decades and oversees major building projects around the country. The Binladin family disowned one of its many members, late al Qaeda leader Osama bin Laden, in the 1990s.''

 

[digger242j]

Oddly enough, it happened on the anniversary of 9/11, celebrated by the attendees.

And just because I'm an "An ounce of prevention is worth a pound of cure" kind of guy, and I can see an enormous potential for a lot of us to want to somehow connect the dots in a political or religious fashion, I'll just post this simple reminder of the forum rules:

No discussion of politics unrelated to the heavy equipment industry should be made. Slanderous references to political beliefs or parties should not be made within these posts, such as flaming lefty, right wing zealot or other similar type label.

No posts of religious or racist content may be made.

 

[lantraxco]

Hell of a storm. Not much information but it looked to me like maybe they had the crane tied off to a load or an anchor point, and when lightning hit it, it parted the hoist line? She went straight back over, her tracks are standing straight up. If it wasn't tied down, I would call that criminal negligence.

 

[old-iron-habit]

What I find odd is that the boom was facing the wind as it went over backwards. The tower cranes we have used for a number of years specify to be not tied off. They are to be stowed with the block pulled up and trolleyed in close to the tower and the machine left with the swing brakes off allowing them to windvane. The last ones I used on a project had a automatic warning system that started beeping at 25 MPH and sounded a long warning horn at 30 MPH wind to give you time to set the load down and unhook. After 3 minutes of steady horn it was designed to put itself in windvane mode to save itself. The wind force on the side of a 250 ft boom is huge. That being said many of our U.S. cranes that do not meet current safety rules here go to other countries for use.

The specs on all the newer big Manitowoc cranes are to not tie them off either but to also let then windmill when out of service. I'm not sure if the one in the picture was a true tower crane or a T-series crawler with a tower boom on it but it should have had the long end of the boom facing straight downwind if it was properly stowed. That being said if the storm was violent enough anything could happen.

EDIT: At first I thought the upturned tracks were another crane that got caught up in the mess. After watching the video again a few times it appears that perhaps the boom was facing down wind. The luffing jib threw me off. It appears to be just a big crawler with luffer, not a tower crane at all. It appears that it went over the same as if it was overloaded. Wonder what the wind was measured at.

 

[Tradesman]

And just because I'm an "An ounce of prevention is worth a pound of cure" kind of guy, and I can see an enormous potential for a lot of us to want to somehow connect the dots in a political or religious fashion, I'll just post this simple reminder of the forum rules:

Well done " nuff said"

 

[ichudov]

Please accept my apologies if my post gave a whiff of political opinion. My mind was focused solely on crane safety and the tragedy that, in insurance language, appears to be an "act of God".

 

[digger242j]

No apology necessary. As I said, an ounce of prevention is worth a pound of cure. I recognize that the events of 9/11 still generate strong feelings for many of us, myself included. On the other hand, I also recognize that the rules have served the forum well, and that while a discussion of this accident in terms of the nuts and bolts aspect is consistent with our mission, venturing into political or religious speculations is not.

 

[lantraxco]

I'm going to guess 60+ on the wind. From the look of the way she went over and what I could see of the crane laying on her back, the operator almost surely set the house lock with the boom over the front of the tracks.

 

[ichudov]

Even on the ground, people seemed barely able to stand up.

 

[John C.]

The little bit of video I saw presented a lot of questions in my mind. I saw the back boom and luffer and then another photo that showed the house and carbody. It appeared the angle of the main boom was way low at the start of the video and the question in my mind was with the main boom that low, where was the wheel horse and back weights. I can't imagine a wind by itself being strong enough to blow over a big crawler. I'm sure there is a large human element in this.

In any case is a mess that will likely take years to sort out.

 

[Knocker of rock]

This is supposed to be how the crane was configured
https://www.washingtonpost.com/worl...c7e0-590b-11e5-abe9-27d53f250b11_graphic.html

 

[lantraxco]

With the boom just about straight up and only the weight of the luffer over the front , wouldn't take all that much wind on a couple hundred feet of boom surface to start it moving backwards, and of course once the main boom went past center it was all over.

John C., I don't see what you're saying about the boom angle? Only video I saw that showed it still up, it was already past center and falling backwards?

 

[John C.]

I apologize for the misstatement on the boom angle. I only saw one piece of video on television and didn't look carefully even at that. The boom might have already been in motion at the starting point of what I saw and it appeared to be a single boom going forward. Now that I think about it I didn't see the queen posts, so going over backwards makes sense. That makes the accident even stranger in my mind. There is not much surface area in a lattice boom and a luffer is usually laid out far enough forward that there is plenty of weight over the front of the house. So for wind to push this over backwards means there was some extremely bad luck or serious human error.

 

[Nige]

Judging from comments in the media a sudden electrical storm with high winds, loads of blown sand, and torrential rain literally came out of nowhere. With the length of boom and luffer on that crane I can see how if it was facing the wind just right it would whip everything over backwards literally in the blink of an eye.

 

[kenh]

The Binladen group state that all was in order.
Shaikh Ahmad Al Gamdi, former head of Makkah’s religious police, told AFP the accident was a “test” from God.

Case closed?
(info from Gulfnews.com)

 

[old-iron-habit]

I was thinking that the crane was not being used. It would seem very odd that they would be hoisting while the area was jam packed with the public. Normally a luffer setup like shown in the post above would have the luffing jib folder over at least parallel to the ground and often folded almost all the way down. The main would normally be lowered to 60 degrees or so also. I think lantraxco got it right and the house lock was on. A "parked" rig shound be in free wind condition. Maybe so many cranes as close as they were did not allow for proper stowing.

 

[Nige]

I'm not an expert on those wheeled counterweights shown in the Washington Post article linked by KOR in Post # 12 on Page 1. Do they permit the upper frame of the machine to weathervane in high winds with the swing brake off..? I would have thought there would be too much friction between the wheels and the ground, especially with the main boom almost vertical and the luffer also pretty well up the weight would be biased well to the rear.

 

[old-iron-habit]

I'm not an expert on those wheeled counterweights shown in the Washington Post article linked by KOR in Post # 12 on Page 1. Do they permit the upper frame of the machine to weathervane in high winds with the swing brake off..? I would have thought there would be too much friction between the wheels and the ground, especially with the main boom almost vertical and the luffer also pretty well up the weight would be biased well to the rear.

I'm not sure how all manufactures accomplish it but I watched Manitowoc test the 21,000 series a number of times during development in 1999 or 2000. ( I lived across the road at the time) Watching them pick 500 tons with 580 ft of boom including luffer, the load would start to lift, the wheels would lift off the ground a ft or so and it always appeared to be balanced when swinging with the wheels off the ground. The wheels were always on the ground when swing with an empty hook. I was to far away to see all the details but I did see the wheels turn 90 degrees and be facing the counterweight a few times. I believe they moved the maxxer counterweight in or out to balance. I am not sure of any changes that may have been made on the production machines. They tipped a luffer and boom over backwards onto the cab once also while working out the erection sequence. No injuries fortunately. As they reported publicly thats why they test in a controlled envirionment.

 

[John C.]

I've seen them work as old-iron-habit says. Most of the ones I've familiar with used the wheel horse to pick up the boom and luffer and then just left it sitting behind the machine on the wheels or taken it off completely. When a max lift was performed the wheel horse was picked off the ground by the machine for the lift and then set back down when the lift was completed. I don't know about it being moved in relation to the center point of the machine but with today's technology I wouldn't doubt it. I have also seen them parked with the luffer in a storage position pointing nearly down or at least parallel to the ground and the boom angle down some. I've also seen the area under the potential fall area cordoned off.

At any rate by the sounds of it, we will never really know what happened .