Expansion loops 1

[SIAUPA]

We perform stress anlysis for a 24" dia steam pipe, running on over 3.5 km. We design a number of expansion loops and considered an anchor on each side of the loop (loop is between two anchors). The pipe passed in Cesar, but our structural engineer tells us that his structure cannot take any moment, and of course we get high moments in the nodes where the anchor is placed.
Somehow I remember that for lines above 6" dia anchors are not to be used. I do not know if this is kind of rule of thumb.
Anyway, could somebody give an idea about how I can avoid anchors. If I use x,y,z restarins only, how does the expansion loop works.
Thank you all.

 

[DSB123]

SIAUPA,
If you do not know how an expansion loop works with using x,y,z restraints I think you should not be performing pipe stress analysis!!!. Leave it to someone who knows what he is doing.

 

[SIAUPA]

Dear DSB123,

I do not perform the analysis.
Even though, I will fully appreciate an answer that helps me learning something.
I expected at least to be guided where to learn from, not to be advised to give up.
Thank you anyway for your time.

 

[DSB123]

SIAUPA,
You can utilise line stops and guides on the system. This will result in axial and lateral forces on the constraint points.

 

[JTHEVENET]

I agree with DSB123, instead of anchors block directions x,y,z on each side of the loop. This will result with only restraints in these directions with no moment. The loop should be also guided on each side (between the loop and the anchor).