Dear All...
There is a question, In CAESAR II what is the different of Restraint one set of X,Y,Z,Rx,Ry,Rz with Anchor?
If i have a long Straight Pipeline about 1.2 Km and i want to give an anchor in somewhere in the middle of the line OR near Expansion Joint, which one that i must input in CAESAR II ? X,Y,Z,Rx,Ry,Rz or just Anchor ?
I want to anchor the pipe with U-bolt over the pipe (tack welded to the pipe) and through-bolted to a bare steel bracket support.

Thanks, please enlighten me...

My Best Regards

Tengku Syahdilan (Aghaton Mandiri)

Hi Dylan

Both the option are technically same.
Some time X Y Z support is used in lieu of anchor to avoid moment at that location. Moment creates more problem for structural design.

Regards

Habib

Thanks Habib, but still i see that the result is the same even in the moment.

Dylan,
Read Habib's response carefully. You will find your answer there.

Regards

Thanks anindya, correct me if i'm wrong. Habib said to avoid moment sometimes better to use XYZ restraint (than X Y Z Rx Ry Rz or anchor) so it still can have rotational movement that reduce the moment at x y and z.

What Habib has said that it is better to avoid rotational restraints wherever possible as because of the six components of load ( 3 forces+3moments) it may be difficult and expensive to design the structure.

Your program is only a mathematical model and it will understand only what you specifically give as input. If you give X.Y,Z it is a translational restraint . If you include RX, Ry and Rz also, it becomes a translational+rotational restraint. A translational restraint only restrains translation ( X,Y,Z movements)and a rotational restraint restricts rotation( Rx, Ry, Rz movements).

I hope it is clear to you now.

Regards

OK, Thanks Anindya, i really appreciate it. It is clear to me now.

Personally I am not a fan of U-bolts, definately if it's functioning as a linestop, be very carefull on how much load you can put on a U-bolt.

Generally, first, you should calculate restraint force and then select a proper support type. U-Bolt with tack weld may fail very soon due to low cycle fatigue, expansion loads, etc.

If the pipe is supported on a steel bracket, it's better to model structure and include it in your piping job, then use CNODE in restraint form to connect Anchor to Steel. You must also check applied loads with structure engineer to design a proper bracket.

If you fully fix pipe, you must use Anchor or X,Y,Z,Rx,Ry,Rz.