Best way to model a thin wall steel pipe

[KyriakosTryphonos]

Hello Everyone

I have a question
I want to perform a dynamic earthquake analysis of a steel pipe that has an initial condition besides its own weight and a uniform internal pressure. The pipe has high ratio radius/wall thickness, so it should behave as a thin shell with only membrane DOFS. I understand that there is no cylindrical element in OpenSees, so will try to approximate the circle with a lot of rectangular elements along the surface.
1) My question is which is the most suitable element for this problem? Shell element seems not the best choice, since it has 6 DOFs but i only need the membrane DOFs.
2) Is it possible to apply the Internal Pressure as Initial Condition State with the InitialStateAnalysisWrapper material so I can have some initial stresses in the material without any initial nodal displacements? I see that is possible for gravity loading from the excavation pile example, but my situation differs and I would like to ask.

Thank you in Advance.