Structural Design of Barge Superstructure

[bootlegend]

I'm looking for any design criteria for superstructures of inland river barges. I am not designing the barge, only the processing equipment and structure that will be on the deck. As a preliminary design I have treated it as a normal static design. Would doing the same for seismic load be a reasonable approach? I've had no luck turning anything up online.

 

[KootK]

I know nothing of barges. I'm curious though: would you even have seismic on a floating structure? I would think so only if your barge were laterally tethered to the ground somehow. Maybe a baby tsunami.

 

[r13]

Try look for US Corp of Engineers (USCOE) design guide.

 

[KootK]

I've got this stuff in the library but I've not read any of it. There was a time when it was looking like was going to have to design a floating amphitheater. Thankfully it went piles.

 

[r13]

Another good source is TVA (Tennessee Valley Authority).

 

[bootlegend]

Okay. Thanks for the ideas so far.

As far as questioning the seismic load, that's what I was trying to reason through. Would a wave create some vertical acceleration, even if no lateral? I'll try to look into the references you all have mentioned. Thanks!

 

[SlideRuleEra]

I'm looking for any design criteria for superstructures of inland river barges. I am not designing the barge, only the processing equipment and structure that will be on the deck.

Seems to me, you are looking for criteria on:

1) How and where to apply loading (the process equipment & structure) to a barge deck.

2) During use of the barge, what forces act on load.

Is that right?

http://www.SlideRuleEra.net

 

[Lomarandil]

I once did a similar design for a temporary application -- it was on the quick and dirty side, but pretty much played out like seismic design. You probably want to coordinate with a naval architect to figure out the horizontal/vertical accelerations to apply based on the barge configuration and operation. Maybe that's simpler for inland waterways, but I think at least a call to a NA is in order.

(You may end up needing to prescribe certain ballast or spud piles be in place during operation)

Barges are sensitive if they're loaded away from the bulkheads/hard points (forgetting the technical term). Make sure you know where those are.


----
just call me Lo.

 

[bootlegend]

SlideRuleEra,
Mostly the second point. I have given the barge designer estimated column loads and locations to the barge designer so we have that accounted for. I also gave them wind loads on my structure based on the barge anchored or fixed. I was looking for any other forces to address in final design, even if only to acknowledge they were not significant.

Lo,
This is going to be a sand dredge so it will be traveling even slower than the typical river barge. I'll see if the barge designer has info on accelerations.

 

[12345abc6ttyui67]

What you need are typical acceleration values for roll, pitch, heave, sway, surge and yaw from the designer of the barge (which are based on how the vessel reacts to wave / wind / currents etc.).

You can then use the acceleration values to apply a %'age of structure / equipment self weight acting laterally, longitudinally, vertically etc. to all the structure above the vessel.

Combine as you fit to cover the worst case vessel motions.

As noted, vessel are generally weak steel (235MPa) so loading at bulkheads or frames is important.

I doubt the barge would be big enough, but for long vessel you also need to account for global bending (and thus deflection) of the vessel hull which can be transmitted to the structure above. Usually one pair of supports are 'fixed' and the other pair are free to slide to accomodate the vessel flexing below.

There are also methods based on the tilt angle of the vessel deck but I'm not familiar with those.

 

[SlideRuleEra]

I was looking for any other forces to address in final design, even if only to acknowledge they were not significant.

Ask the barge designer for the maximum acceptable list angle. Use this to calculate both overturning and sliding force of the equipment/structure. This is a big deal for a crawler or truck crane temporarily lashed to a barge, lifting a heavy load while boomed out. Maybe not so much if the equipment is "compact" and permanently installed.

Horizontal acceleration has been mentioned. This is important, barges get "banged" around even during normal operation. Perhaps the barge designer can give you a design horizontal impact loading.

If there will be a significant quantity of liquid on board that can be "shift" while the barge is listing (say, in a partially filled tank), tell the barge designer. On-board liquid movement is a "wild card" that play havoc on stability.

http://www.SlideRuleEra.net

 

[Rabbit12]

Major oil and gas companies will have some information in their specifications. Used to analyze sealift modules that are transported by barge.

 

[Lomarandil]

For the sake of over-communicating what Random noted, it's important that the critical accelerations (roll,pitch,etc) are not so much due to barge transit/action as due to actions of the wind/waves/current acting on the barge. Ships (especially barges) are large compared to their engines and winches, but also provide a lot of surface area for environmental loads to act on.

----
just call me Lo.

 

[chicopee]

If you intent of having the barge be used to support a mobile crane (hydraulic or lattice boom, regardless) have a structural engineer qualified in that type of work examine the internasl of the barge for proper support of the deck. At one time the company for which I worked did reinforced the structural support under the deck of a barge to support our cranes and our C.E. as well as the supplier or manufacturer of that barge had made recommendations to weld more steel under the deck. The supplier or manufacturer are your best source of information. Also use dunnage to protect the deck from being damaged by the equipment and also to spread the load from that equipment. Foremost make sure the barge is capable of supporting the equipment by having enough freeboard consistent with OSHA construction 1910.

 

[chicopee]

two more idea; the freeboard requirement has to be maintained when the barge is listing from equipment load and operations; also adequate VENTILATIONn under the deck is needed when welding additional steel in a CONFINED SPACE.