U/G pipes

[B.L.Smith]

Dear Sirs,

Why do we use thrust block in U/G lines and not in A/G lines? If thrust block should be used for preventing separation of joints, why it do not uses in A/G?

Thanks for your consideration.

Beast regards

 

[DSB123]

Most A/G lines are welded joints hence thrust blocks are not generally required. If the A/G pipe were ball and spigot joints or similar then thrust blocks would be required.

 

[B.L.Smith]

But I have seen for bell and spigot connection in A/G do not use of thrust block but for U/G use of it. why?

 

[C2it]

Logically, the joints you have seen must somehow be restrained agianst effects of axial force due to pressure, or there is never any internal pressure.

 

[BigInch]

If you have a straight length on either side of a bell-spigot joints that is long enough to develop enough restraining force by friction through contact with the surrounding soil, then thrust blocks are not necessary. That is usually the case when the pipes are in a straight line. When there is a turn in the line and an angle is necessary, the soil friction along the pipes will not be at the proper angles to balance the pressure thrust forces and in that case any unbalanced forces that result must be counteracted by an anchor thrust block. Sum Fx + Sum Fy must be 0.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[BigInch]

Come see my presentation on the use/disuse of anchor blocks at the Abu Dhabi Transmission Pipeline Summit 8-12 Sept.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[B.L.Smith]

Thanks dear BigInch. Is there any difference between bell&spigot and lamination in using of thrust block?
May I read your article about thrust blocks?

 

[BigInch]

Lamination?

I think it will be available towards the end of next week.
I will check to see if I can post it here.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[B.L.Smith]

Thanks Mr. BigInch for the article.
Lamination connection for GRP pipes is similar to buttweld connection for steel pipes.

 

[BigInch]

Thanks. I didn't know that term. I haven't learned about GRP ... yet.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek