Subsea analysis - weight in hydrotest condition

In the framework of a subsea pipeline calculation, I noticed that the same load case corresponding to pipe filled with water (WW) leads to different vertical reaction on supports if the stress type is HYD compared to OPE or SUS: with HYD the loads are lower (about 20% less).

As far as I know there is no theoretical basis for this and comparing CAESAR results with hand calculated pipe and content weight, the higher values seem to be the correct ones.

In this case, calculation of Hydrotest condition would be uncorrect, on the unsafe side.

Can someone help me on this topic?

Thanks in advance.

A nice day to all.

P72

As far as I know, selecting HYD as the stress type tells the program not to include the weight of insulation for the case. That may explain the difference.

There are a few other differences:

1) To include or not include insulation can be controlled by the configuration file.

2) The HYD case also locks spring hangers (makes the stiffness rigid).

3) The HYD case also locks expansion joints (makes them rigid).

About the three points above:

1) insulation is included also in the HYD case by the relevant setting in configuration file (insulation is in this case the concrete coating necessary to overcome bouyancy and it is absolutely necessary to stabilize the system), moreover the difference remains also running calculation without insulation.

2) there are no spring hangers

3) there are no expansion joint


The problem is unsolved.

Regards,
P72

Open a Support Request on Smart Support and send in the job file so the Technical Support Group can look at it.