Dear Stress Engrs,

Our client requires our tanks to have Roller BEarings to mitigate the seismic movements.

Anyone here have an idea how to consider this in our stress analysis?

My idea is that since the tanks have rollers, seismic movements of the tank will have zero to minimal effect on our piping.

Hello,

My idea for tank piping would be the following:

1) Check with Civil group if there will be some settlement.
2) If the diameter of tank is greater than 36m check with Mechanical group if they will use API 650 or FEA. In new edition of API 650 I think FEA is now an option. I think if FEA will be used maybe the boundary condition that will be used by Vendor would be simple to simulate roller bearing instead of fixed. Anyway it would be under tank vendor's scope to perform such analysis.
3) With regards to the seismic, I think there will be no lateral movement in the tank due to seismic since roller bearing is used. Anyway, this will be under Mechanical group/Vendor scope to determine this. You can confirm with them just to make sure. Please share their response cause I haven't tried before a tank subjected to seismic.
4) As usual input the unrestrained outward radial growth of the shell at the center of the opening connection resulting from product head and/or thermal expansion
and the unrestrained rotation of the shell at the center of the nozzle-shell connection resulting from product head.

Any other opinion is greatly appreciated.

Cheers!!