API 650 Stiffening Ring Flatbar ok? 1

[ianertia]

An engineer I work with that is one of the most knowledgeable people on API 650 in my workplace designed a tank with a stiffener about halfway up the tank. A construction guy has been telling me that the flatbar used for the stiffener is not to API, but the engineer says it is. I see in API where it shows common styles of stiffeners as angle iron, but is flat bar acceptable as long as it can handle the loads needed?

 

[JStephen]

"Stiffening rings may be made of structural sections, formed plate sections, sections built up by welding, or combinations of such types of sections assembled by welding" per 5.9.2. That seems to leave it open to just about any shape. Note, though, that the rules don't necessarily cover every shape in detail.

For flat bar in particular, note the width limitations applied to compression rings in Figure F.2.

 

[bimr]

Angle iron is normally used as a stiffener. Angle iron is more economical than flat bar because of the larger cross-sectional properties for stiffening.

 

[ianertia]

Thank ya'll for the response!