Floating of a 1.6mtr x 19mm x 60 mtr steel tube

In summary, the author is designing a steel tube that will be welded together using the collar sleeve method. The flanges will have a 1" valve at the top and a 2" valve at the bottom. The plan is to float the tube along side a barge then have two cranes (42 ton capacity each) to tie onto the pipe say 10 mtr from each end. Once this is completed both 2" lower valves will be opened and then the 1" upper valve will be opened to control the flooding speed. The final water depth when the pipe is sunk (but still boyant) is 6mtr. The author was considering welding some kind of baffle arrangement inside the tube (for stability), but as it
  • #1
sbgce
1
0
Appreciate any comments regarding the following:-(I am not an Engineer)
We intend to launch (Mekong River) the subject steel tube (12mtr pipe welded together using the collar sleeve method) Flanges / gasket will be fitted at both ends of the tube. The flanges will have a 1" valve at the top and a 2" valve at the bottom. The plan is to float the tube (using two tugs) along side a barge then have two cranes(42 ton capacity each) to tie onto the pipe say 10 mtr from each end. once this is completed both 2" lower valves will be opened and then the 1" upper valve will be opened to control the flooding speed. final water depth when pipe is sunk (but still boyant is 6mtr - The river flow volocity will be approx 2mtr/min - I was considering welding some kind of baffle arrangment inside the tube (for stability) but as it has been coated I don't want to damage this . I am concerned that I may not get even (level) submerging when opening the valves. Also once the 1" valve is under water and the tube slowing submerging down to the 6mtr level - what effect will this have on the 1" bleed valve (back pressure??) At the 6mtr level the barge (by using winches) will slowly move the tube into position to connect (by Flanges) to a stationary pipe comming from the river bank.
Any comments would really be appreciated.

Thanks
 
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  • #2
sbgce: By the way, the unit symbol for meter is m. E.g., 1.6 m, not 1.6 mtr. Also, always leave a space between a numeric value and its following unit symbol. E.g., 1.6 m, not 1.6m.

I think the pipe flooding rate will slightly decrease after the upper valve submerges (but this slight change in rate might not even be noticeable). And the flooding rate will continue at this same slightly slower rate thereafter, regardless of the pipe depth.

Therefore, I would say, let the upper valves submerge just below the water surface, and hold the pipe at that location with the cranes, and wait, until the pipe essentially finishes flooding. Now, with the pipe completely flooded, there is no opportunity for tilting (instability). Therefore, you can now proceed to lower the pipe to the desired depth.

PS: I think you can perhaps expedite final flooding by keeping one of the two upper valves, say, 100 mm below the water surface, and keeping the other upper value 20 mm above the water surface. Then, when air stops flowing out of the second upper valve, you can submerge the second upper valve, and hold the pipe at that location, per paragraph 3, until air stops escaping.
 
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  • #3
Welcome to PF, Sbgce.
I'm pretty sure that I'm missing something here, because the scenario doesn't make sense to me. Why not just leave the pipes open, walk them into position with the barge cranes, and slowly lower them into position? If you're going to flood them anyhow, why would you bother to water-proof them in the first place?
 

Related to Floating of a 1.6mtr x 19mm x 60 mtr steel tube

1. What is the purpose of floating a steel tube?

The purpose of floating a steel tube is to create a buoyant structure that can be used for various applications such as offshore oil drilling, marine construction, and transportation of materials over water. This allows for easier and more efficient access to areas that are not easily reachable by land.

2. How does the steel tube float?

The steel tube floats due to the principle of buoyancy, which states that an object will float if it displaces an amount of water equal to its own weight. The steel tube is designed to have a lower density than water, making it float on the surface.

3. What factors affect the floating of a steel tube?

The main factors that affect the floating of a steel tube are its weight, shape, and size. The weight of the steel tube should be less than the weight of the water it displaces, and the shape and size of the tube can also impact its buoyancy. Other factors such as external forces, water currents, and the distribution of weight on the tube can also affect its floating ability.

4. What precautions should be taken when floating a steel tube?

When floating a steel tube, it is important to ensure that it is properly secured and stabilized to prevent it from capsizing or drifting away. The weight distribution on the tube should also be carefully considered to maintain its balance and stability. It is also crucial to monitor and adjust for changing water conditions to prevent any accidents or damage to the tube.

5. How is the floating of a steel tube beneficial to the environment?

Floating a steel tube can have several environmental benefits. It can minimize land disturbance and reduce the need for building bridges or other structures over water. It can also reduce the carbon footprint of transporting materials over water instead of by land. Additionally, floating structures can provide a habitat for marine life and help protect coastlines from erosion.

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