Stiffener rings on horizontal vessel

[Bobfromoh]

There is an external load on a horizontal vessel. According to the Zick analysis, stiffener rings are required to reduce the stresses to an acceptable level. The problem is determining the weld size to attach the ring to the shell.

The ASME Code in the Appendix shows a method to calculate the weld size due to pressure. But it doesn't show how to include an external force. The radial shear is needed to use the Code equations. In the book "Formulas for Stress and Strain" by Young, there is a method to find the tangential shear but not the radial shear.

Zick doesn't cover sizing the ring to shell weld. The vessel software I use doesn't include this calculation either. Does anyone know a method to size the stiffener ring weld?

 

[chaulklate]

For stiffening ring weld size, try referring to UG-30(e). This section also refers to Appendix L-5 for a sample calculation. I haven't checked the exact example, hope it helps.

 

[mammut74]

Hi Bobformoh,

Some questions:
What load is this and the direction it acts e.g. Blast load acting over a large area or point loads e.g a nozzle load?

And how did you impose the load onto vessel for the LP Zick analysis?

Thanks.

 

[Bobfromoh]

The HX supports an external load that is transfered to the supports. This load doubles the load from the HX. The Zick analysis says a stiffener ring is required to reduce the stresses. The Code only provides direction to size the welds from pressure loads, not from external loads.