I wonder if any one can advise a reference to help in sizing the repad at anchor chair. Repad sizing is required by a third party inspector. Repad was selected due to high stress at shell caused by anchor chairs.>25,000 psi.
Is there any document or standard to be used in repad sizing , as this sizing is required by third party inspector and approximation won't work. I know ASME VIII Div II has these calculations for pressure vessels.
I have had the same question. I'm still looking for a good reference that will direct me in the design of these repads. CHeck out this thread I posted a long time ago.
Repads are not typically used for anchor chairs. Normally the lower shell course is thickened to handle the local stresses at the anchor chair. Alternatively, the anchor chair size (height and width) is increased to lower the stress to accepatble levels.
Adding a repad around the anchor chair is an economic alternative to increasing the fisrt shell ring size. I have a tank in which the fisrt shell ring is 1/4" thick. If I were to increas it's thickness to comply with the 25,000 psi requiremeent, I would need to increase it to 5/8".
Jorge L. Ramos, Jr., MSCE, PE
Alonso & Carus Iron Works, Inc. (