Ever built a shipable storage tank? 3

[vesselguy]

Has anyone ever built, or know of, a large diameter (50ft or more) API storage tank that was completed in a shop and was shipped to a job site intact? Such a tank may be sitting on a large skid and it would just be lift and dropped into place. If you do know of such a beast, can you share a bit of insight about what was done? Thanks.

 

[SnTMan]

vesselguy, based on what little I know of shipping heat exchangers I would say that shipping 50' dia. by rail or road is out.

Maybe if all by water it could be done, but you'd have to build it on the barge I think.

Regards,

Mike

 

[vesselfab]

I would think that lifting this big beast without colapsing the would be a problem. I guess you could build multi level skid so you could lift from top.

moving from barge dock to erection site could be a real problem as well.

Get's heavier and more complicated all the time.

 

[SnTMan]

Well, anything can be done, it's just time & money.

Regards,

Mike

 

[vesselguy]

Yes, its just time and money.

Road restriction is not an issue as the job site is next to water so it can be barged in. My real concern is building a support structure so that the tank can be lifted and, more importantly, survive the transverse forces imposed on it by the pitching and rolling of the ship at sea. This is crazy but I get paid by the hour.

I thought others might have already tackled this problem and I could see what they've done so I don't have to reinvent the wheel.

 

[LOUDOG]

It sounds as though shipping it would be more expensive than field building the unit. You would need a very large and expensive crane, you would need to fully skid the floor so it did not collaspe, you would need large external rafters as to not cave the roof.

It sounds way more expensive than field building it. Even if you needed to buy a crane to ship to site, it would probably be cheaper.

Unless you get really creative... Build a large circular spreader bar to lift the tank about the perimeter, and have removeable tie bars from the roof down to support the floor.

Sounds like fun.

 

[BUTCHCWIQAM]

I have built tanks over the 50' mark. We had to lay them on their sides and weld the rear wheels to the tank,they had stiffing rings... there were a lot of restrictions like could only travel at night and need 2 escorts and as i recall a lot of state permits to pay off... I mean to buy.
Tank was under the 15' diameter and 50'+ length, this has been many years ago way before the digital camera age... I wish I had pictures to share just old fading memories.most trailers on the road today are 45'+ if I remember correctly the tank sat only a few inches from the ground

 

[vesselguy]

Fun??? It's a challenge that's for sure.

Myself and another engineer arrived at the similar concept independently to make this happend. But, I sure would like to have something similar to have a reality check against.

BTUCHCWIQAM, You had a lot of stiffening rings because you lay your tank on the side and you wanted to reduce ovalization of the shell. Did you use double sided partial penetration welds for the shell to bottom welds to reduce the changes of cracking and increased strength? What did you do for the roof joints? Do you remember if you experience any cracks from the transport?

 

[BUTCHCWIQAM]

The heads were coned with stiffeners every 2' and I remember after the first post we added stiffeners inside and ran, I beam along the base between wheels I am sorry for the vague details but this was about 20 years ago, and we did not use computers to track everything, I wish we had these tools back then things would have been a lot easier can you imagin the information lost because of bad memories and time .. I do not remember any cracking problems but that does not mean that tonight it may come back like a lighting bolt. Right now I don't remember doing this any other time so there may have been problems that I was not made aware of, I was a little younger and had just started to Push Jobs.

 

[JStephen]

One thing that comes to mind is that when you used up all the room on a barge with the tanks, you might only have 1/10 of the weight capacity accounted for. So you'd have a lot lower shipping cost per tank if they were knocked down.

It wouldn't be hard to hold the tanks down for sea forces, as you could add anchor bolt chairs and tie down like a finished tank. The major load in many cases is seismic loading on a full tank, and with an empty tank that is eliminted. I suspect the bigger problem would be lack of tie down points at the right place on the barge itself.

I wonder if shipping costs more for high-profile loads, due to extra wind resistance.

I've heard of Russian tanks having the complete shell fabricated into one piece in the shop, and then somehow flattened or rolled up- not sure of the details.

 

[BUTCHCWIQAM]

I have built tanks in Puerto Rico that had been fabricated in rolls and shipped to PR via Barge, Tanks were 75,000 gallon heads were dished and cut into 2 pieces bottom was coned and sat inside a carbon steel skirt... the company I use to work for was big in shipping roles to the Job site you only had one vertical seam in the field if I remember correctly the tank height was 48'X 24' dia

 

[JohnGP]

vesselguy,

Sorry, not 50ft, but just for your info as some of the same principles apply - on my present project we shipped in many tanks around the 40ft diameter, and one at 45ft diameter. Most of the journey was by sea, but at the fabrication yard and at site, transporters were used (operating two abreast for these larger tanks).

The tanks had 4 padeyes welded through the top ring for lifting, and two lifting beams positioned below the cranes beam to provide vertical lifting at each point. Most tanks had platforms with up to 8 support legs to the tank wall which probably provided additional lateral stability of the tank top above that provided by the ring. The largest tank mentioned above had a cone roof as well.

To overcome concerns regarding tank floor bending, an internal ring was welded to the floor and cables tensioned from the ring back up to lugs welded to the internal wall. This system worked Ok - the tanks arrived at site with no more problems than what they left the fabrication yard with. We had also specified butt weld floors specifically because of the lifting and handling that the tanks had to endure.

For transport we had the fabricator provide stiffened sections around the base to attach chains for road transport and hold-downs for sea transport, with additional reinforced lugs welded around the circumference, generally halfway up the shell, but calculated to be in sufficient number to withstand the generalised sea loadings.

Regards,
John

 

[doct9960]

vesselguy,

How about "air lifting"...

http://arwatson.com/main/

Here are some videos...

http://arwatson.com/main/?page_id=19

 

[vesselguy]

Thanks all you guys for your input.

doct9960, Airlifting eh? It might be a good idea to lift a tank from the ship to the foundation instead of crawlers. We'll see.

JohnGP, you have given me some good pointers for consideration, although I don't really understand some of the set up you were trying to explain. That's why one picture is worth a thousand words.

This is essentially a structural problem, the tank is just incidental. Hence I'm working with a structural engineer to model my skeleton on STADD to check deflection. So far the structure is looking good and top deflection during rolling of the ship is less than 1 inch. This might just be crazy enough to work.

 

[JohnGP]

vesselguy,

What was done worked for us - if you need further detail/clarification then let me know. I would love to send some photos but that is not possible. I could maybe sketch something up next week when I'm off site if that would help.

Regards,
John

 

[doct9960]

vesselguy,

doct9960, Airlifting eh? It might be a good idea to lift a tank from the ship to the foundation instead of crawlers. We'll see.

Well, you can "crawl" the tank from land to ship,or vice versa, with the use of transport carriers like this one...

http://www2.dockwise.com/files/images/DW0204407_UW_FOL_ENTERPRISE.pdf

If you'll browse through the Dockwise website (

http://www2.dockwise.com),

you'll find much bigger "beasts" transported by sea.

Let us know how your project turns out. I'm very much interested in how the tank would be lifted. I've never heard of a >50 ft. diameter tank that's shop fabricated and shipped to site before. Would be great if your tank gets televised in Discovery Channel shows like Extreme Engineering or Monster Moves.

 

[vesselguy]

doct9960,
Yeah, I never heard of such thing (nor dream of such thing) until I was asked to do this. At first I thought what the hell, are they crazy??? Then I thought about it and asked a structual engineer to model some structures, then it is starting to look not so crazy after all. We'll see what happens.

 

[racookpe1978]

Two movements?

Either build it on-shore at your plant and load TO the barge there, then OFF the barge at the construction site.

Or build it on the barge at your site (as mentioned above) - but remember to add barge "rental time" costs while you build it on the barge at your site.