Shocking crane barge accident

Free surface in tanks does have the effect of reducing the stability of the barge.

Road cranes can be used safely on pontoons, but you can't be careless about it.

It will be interesting to see if the company involved in installing the new bridge section used the services of a naval architect to investigate the stability of the barges and equipment used.

 

Just may reduce the metacentric height which produces a consequent reduction in the stability of the barge.

 

Yes, that was one of the things he said.

I only gave a very brief summary in two sentences in my own words translated into a for me foreign language of the over 4 ½ minutes of speech in the video, the speaker himself (Jan Zwagerman) was much more clear and said much more than what I wrote in the summary.

One of the others things he said is; in a crane pontoon the ballast water needs to be in separated compartments and needs to be pumped between the compartments in the opposite direction with respect to the movements of the crane. Which should be common knowledge for everyone in the boat and crane business I think.

On their website I found the crane barge Conquest MB1 with a rotating crane attached to the vessel, which I guess has such separated and pump controlled ballast water compartments he was talking about.

The Conquest MB1 was also on the scene to carry out the installation of the 19 sponsons weighting 800mt each to refloat Costa Concordia when she was salvaged from the rocks off Giglio in Italy.

In above video by "spongoons" could be meant "sponsons" but I'm not sure, also I'm not sure at 49 sec "without counterweight" is correct, it seems more likely to me the counterweight is controlled ballast water in separated compartments, like Jan Zwagerman was talking about in the previous video (see post #28).

I think the bridge job in Alphen could have been carried out perfectly by the Conquest MB1 or if too wide by a smaller version, or by land cranes stationed on the bridge heads as was done before (see post #5).

 

Yes, found it in the specs...(PDF)... ‘‘ Fully automatic ballast (anti heeling) system ’’

 

Here's a link to go with that pic, and 14 more pictures, but I'm not sure the Conquest MB1 can be seen on anyone of them . . . .

 

The point is, when using water ballast, it's a good idea to press the tanks full and not have any tanks partially filled, where a free surface is created. Pressing a ballast tank usually means filling it until water comes out the vents (if the tank is so equipped).

 

I was down at the end of the building when this device collapsed with it's 540 ton load. In the second photo, the small crane crushed under the blue beam saved a number of lives, a bunch of people crawled out from under it there. As it was, 1 person died and 10 were injured.

 

Yes, when the tanks can be either full or empty during the whole job and a little heeling while rotating the crane + load can be tolerated. But when a little heeling can't be tolerated then in an anti heeling ballast system the water needs to be moved during the job in the opposite direction of the movements of the crane. Then the tanks can't be 100% full all the time while pumping, then it's best to have many small separate compartments I think. Which shouldn't be a problem as a deck strength of 20 ton/m² needs a lot of longitudinal and transverse support which could be given by reinforced longitudinal and transverse bulkheads, so there you have the many tanks that can be controlled by a fully automatic ballast (anti heeling) system. The mentioned deck strength comes from the Conquest MB1 specs (PDF).

 

What you say is true, and there are barges which are designed with ballast systems that can be flooded or emptied to counterballast a crane.

But, some contractors use cranes placed on plain-old deck barges, which are not built with these specialized ballast systems, indeed, may not be built to handle water ballast at all, because they're deck barges, not crane barges. In those cases, it becomes all the more important to have a naval architect examine the proposed lift, understanding the limitations of the equipment selected.

If the barge is not equipped with a ballast system, it's better to have the tanks completely empty or pressed full.

Of course, if there is a sudden loss of load from the crane, then what happens to the barge in this event must be investigated to make sure that the crane or the safety of any personnel on the barge is not jeopardized.

 

No they did not consult with any experts, which must be improved in the future, says Jan Pesie the director of the main contractor BSB Staalbouw in an interview.

Shocking is the sentence in which he indicates that he thinks experts on this terrain are as incompetent as he is on this matter . . .

 

Below two videos of the above interview, both videos are in Dutch . . .

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Contractor BSB Staalbouw on the accident with the Queen Juliana Bridge in Alphen aan den Rijn

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Jan Pesie, director of the main contractor BSB Staalbouw: ‘‘ Misfortune Queen Juliana bridge is a big blow for us ’’​

 

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Abstract from the above Dutch links:

Mammoet and HEBO are contracted to do the salvaging of the bridge section plus the cranes and the barges from this havoc, which could take about two months to carry out the linked articles say.

Mammoet did together with Smit the salvage of the Russian submarine Kursk ---> recovery.

 

The sad thing is the land guys thought they could move their crane operations onto a floating barge without worrying about the consequences. Even in a small country like Holland, one can call on the services of naval architects and marine surveyors who have a vast knowledge of how to prepare barges and equipment to carry out such work safely.

Pride goeth before the fall ...

 

It's either pride or stupidity. It still did not reached this steel contractor that floating on water is not as stable as standing on the land. In the interview the director said nobody could foresee this misfortune.

This man apparently doesn't know or is in denial that others are more knowledgeable on in this field than he is and that they could have calculated there was a high risk for an accident when working with this setup.

So he didn't consult any expert, but he will in the future, but he also says that this will not prevent any accident like this.