Good evening everyone,
I am doing the analysis for condenser supply and return lines. the line is going under ground and at the bends I have provided thrust block. My thrust forces are coming 650 Tonnes. At the site there is not enough space to provide the thrust block for so much forces. The civil people has ask me to reduce the forces coming at bend.
I need to know how I can reduce the forces? Apart from rerouting, do we have any other solution?
My pipe OD is 2032mm, pressure is 4kg/cm2 and temp. is 45 deg C.

Eagerly waiting for your response.

Reagrds,
Peter.

You could try -

1) increasing your installation/backfilling temperature so you have less delta T to deal with,

2) Allow a nominal movement of say 1/2" at the blocks, see what the reduced anchor force is, and give that value to the civil engineers

The question is: The thrust block is really necessary?

Thank you Dave Clark.

Miyamoto, without thrust block my forces are coming ok. but with thrust block, the forces are increasing too much.

Shall I provide thrust block?

Regards,
Peter

If you have welded joint steel pipe then you likely do not need Thrust Blocks.

If you have mechanical joint Cast Iron (or other material) pipe then you may need Thrust Blocks to keep the joints from coming apart.

So, what is the materials and construction of your system?

And is the piping overstressed or having excessive displacement without thrust blocks?

My pipe material is API 5L Gr.B
I checked the stresses and found that stresses are normal.
I also checked the displacement and below i have written the valve also.
DX(mm) DY(mm) DZ(mm)
Sus. Case -0.011 -0.616 0.075
Ope. Case -10 -0.747 0.393
Exp. Case -10.215 -0.131 0.318

Now can you please suggest me shall I use Thrust Block?

Thank you for your response Jop and Dave Clark.

Jop asked about the construction, is it a butt welded piping system?

Why were thrust blocks modelled in the first place? If without thrust blocks the piping's displacements, reaction forces, and stresses are OK and the piping otherwise meets code, then what purpose are the thrust blocks serving?

So friends,
Shall I use the Thrust block?

Thanks and regards,
Peter.

The question:
Shall I use the Thrust block?

My vote:
NO!

Thank you Jop and thank you all for your suggestions.

Regards,
Peter.

Mr. Richard,
Can you tell me the final answer.

Jop, dont mind. I am not underestimating your answer. But for confirmation I need Mr. Richard's view.Because I have to face client.

And my dear members, you all are also requested to share your skills/experience on the above topic.

Thanks and regrads,
Peter.

Peter,

You did not answer Dave Clark's important question about jointing. If your pipe is welded, why was a thrust block considered in the first place ?

If the pipe is not welded, what kind of joint are you using ?

650 tonnes is an enourmous load, it can't all be due to pressure thrust. Have you investigated where the load has originated ?

I agree with MoverZ.

Moverz,
sorry I forgot to mention, the joint between pipe and elbow is butt welded joint.
The project manager had asked me to provide the thrust block so i have considered.

If I were there I would tell the Project Manager that:
a) Welded pipe does not need Thrust Blocks underground or above ground. And that is the telling point: If welded joint carbon steel pipe does not need thrust blocks above ground why does it need thrust blocks for underground. He might try to bring up the use of Anchors employed in high temperature above ground piping (expansion loops, etc.) however that is a totally different subject.

b) I would then remind him that his job for the Client as well as mine is the hold down the total installed cost of the job. Installing unnecessary high cost items does not meet that criteria.

Thank you Jop and thank you all my friends for sharing your opinion.

Regards,
Peter.

Dears

I searched nearly all previous relevant posts. but i couldn't get for what sizes or pressure or else are thrust blocks used?as i know adhesive-bonded joints and welded types do not require thrust blocks. what are the other criteria for using them. in UKOOA code some joints are mentioned as thrust-resistant.

Thanks

any help please.

Dear Piper,

/////as i know adhesive-bonded joints and welded types do not require thrust blocks ///////? Please reply for your statement.

Suppose, For GRE Pipes, Adhesive bonded joints (Tapered Bell/Tapered Spigot),
How do you control the axial stress/axial displacement.

For GRP Underground Pipes, we used to provide the thrust blocks in order to control the axial displacement.

Kindly reply me Piper, are you working with GRP/GRE field.

Thanks

Dear Piper,

/////as i know adhesive-bonded joints and welded types do not require thrust blocks ///////? Please reply for your statement.

Suppose, For GRE Pipes, Adhesive bonded joints (Tapered Bell/Tapered Spigot),
How do you control the axial stress/axial displacement.

For GRP Underground Pipes, we used to provide the thrust blocks in order to control the axial displacement.

Kindly reply me Piper, are you working with GRP/GRE field.

Thanks