rectangular reservoir reinforcements

[Cast16]

Bye to all,

Rectangular tank with flat bar ribs. I remember reading somewhere that there is a limit in the height/thickness ratio of the flat rib that you can use, but I can't find it. exists such an indication in some guideline and what is the value?

 

[meccanicamg]

I don't know. I would do a fem and see. At some point you will see that nothing changes no more despite changing the size of the rib.

 

[ceschi1959]

Bye to all,

Rectangular tank with flat bar ribs. I remember reading somewhere that there is a limit in the height/thickness ratio of the flat rib that you can use, but I can't find it. exists such an indication in some guideline and what is the value?
View attachment 69123

Are you referring perhaps to slenderness and therefore to the instability to the tip load?

 

[PIETRO2002]

Are you referring perhaps to slenderness and therefore to the instability to the tip load?

but in this case the dishes are not subject to peak load.

 

[ceschi1959]

but in this case the dishes are not subject to peak load.

In fact, mine was a rhetorical question.

 

[Betoniera]

ciao cast16Rectangular tank with flat bar ribs. I remember reading somewhere that there is a limit in the height/thickness ratio of the flat rib that you can use, but I can't find it. exists such an indication in some guideline and what is the value?I think it is necessary to refer to the rules on thin-wall profiles.
This is not stiffened rib.
the uni 10022 at point 3.1.4 places the limits indicated below.
if the rib is t=1 mm the effective width is b=30 mm.
even if the rib is greater, the resistant section is always the effective one.
the uni 10022 is no longer in force, replaced by ec3, but the principles are always those.
the fem modeling will highlight the stretched parts and those tablets, but not the instability obtainable only with buckling analysis.
Bye.

 

[Cast16]

thanks to all for the answers received.

I had made a fea (statelinear) with hydrostatic pressure, and I detected a maximum deformation of 0.7 mm (sewer with a thickness of 6 mm). I do not know how to set buckling analysis in nastran for the tank with hydrostatic pressure, but I do not believe that flat reinforcements in this case (150x10mm) fail. what comes to my mind because you do not see such high reinforcements not tied horizontally, would be to prevent a possible deformation due to accidental blows on the ends.

However, I discussed with the customer, and confirmed that they used similar models in the past without problems.

Thank you. @betoniera to have posted the norm.
I'm sure somewhere (among several books I had downloaded on the tanks) I saw mentioned as a guideline that report I remember was lower than 30.