I've been asked to do an anlysis of a pipeline that is laid on the ground - continuously supported. What is the best way to model this in CAESAR - apply a continuous load vertically up equal to the per foot weight of the pipe and contents?

Depends what you are looking for.

Is this miles of pipe? Is it following the terrain (hills and dales)? How stiff is the ground?

I would not use a force to model this boundary condition. A force will not vary with position. A restraint can be set to relate support load with (up and down) position. A +Y restraint, for example, would not allow downward movement.

But these are point restraints and not the continuous restraint that you have in the field. You could use the break command to put many, many restraints on an existing run. Or, you could use the program's buried pipe modeler and edit the resulting model to suit your purpose.

Thanks Dave - the first choice seems the easiest (at least for me), but I will investigate the buried modeller.

Dear specialist;

What is the best way to model above ground pipelines continuously in contact with soil? Is it by providing supports with short span or by using Buried modeler included in Caesar II.

In case we use Buried Modeler of Caesar II, what will be the Burial depth since the pipe is burried infact?


Thanx

Dear specialist;

What is the best way to model above ground pipelines continuously in contact with soil? Is it by providing supports with short span or by using Buried modeler included in Caesar II.

In case we use Buried Modeler of Caesar II, what will be the Burial depth since the pipe is burried infact?


Thanx

The theory and therefore the equations used in the CAESAR II "Buried Pipe Modeler" assume the pipe is completely buried. If that is not your case, then the soil stiffnesses computed by CAESAR II are not applicable.

Thanks Richard;
I noticed that some stress engineers uses Buried Modeler with special input parameters such as burial depth of 50mm just to simulate the soil effect.

In your previous answer to me you rejected this procedure, what whall the correct one to model an above ground pipeline.

I can't answer that question. I haven't seen a published procedure that addresses this situation. If you decide to "push the envelope", you may be ok, or you may be off by several hundred percent.

So there is no resolution for this condition? I 'd like to know what is the most common practice to represent this lay out. i.e. Miles of pipe lying on the ground.
This seems to be a very common situation. May be Intergraph should develop the special modeler just like the buried pipe or provide reasonable methodology for the modeling representation.

What about making total weight of the system (Pipe, fluid etc)zero?