Dear members,
Please advice how to analyze the hydrotest condition in Caesar-II for GRP buried piping.

For buried GRP piping vendor inputted the hydtotest pressure in P2 in stead of hydrotest pressure in the input sheet.
And showed the load case as W+P2 as the hydrotest condition.

However for Carbon steel we input hydrotest pressure in input sheet & refer the WW+ HYD load case.
For GRP buried piping if I input the hydrotest pressure in input and refer the WW+ HYD load case it is a stress failure but with same pressure as W+P2 it is stress pass.
Please advice the correct procedure for GRP piping stress analysis

The CAESAR II Buried Pipe Modeler sets the densities (of the pipe, the fluid, and the insulation) to zero, since the pipe is continuously supported in the field. The numerical model however uses discrete node points, so the only way to avoid weight stress is to zero the density.

When you use the "HYD" load case and the "WW" load primative, you're using "Weight of Water", which is not zero, hence the overstress.

In this instance, you should follow your vendor's advice.