seismic overturning moment of a horizontal tank

[Peace10]

Hello Everybody !!

Im new in this forum & i hope to find a good answer for this question . how to calculate the seismic overturning moment of a horizontal tank ??

 

[JStephen]

Figure out which code specifies seismic loading for your situation. Read it. In the US, this is typically ASCE 7.

 

[MJCronin]

A methodology for seismic evaluation of flat bottomed tanks is contained in the Appendices of API-650.

The percentage full of an API-650 tank undergoing an earthquake has a strong effect on the amount of damage done.

All new tanks expected to survive an earthquake intact must be robustly bolted to the foundation.

MJCronin
Sr. Process Engineer
Venture Engineering & Construction

http://www.VentureEngr.com

 

[msquared48]

All it is is multiplying the seismic force (code generated), as applied through the CG of the tank, both with and without liquid, and multiplied by the lever arm to both the top of the foundation for the bolting forces, and the bottom of the foundation for the soil pressures, and then calculating the resisting moment using the weight of the filled and unfilled tank times the distance to the periphery of the foundation footing. Make sure that the resisting moment divided by the overturning moment is at least 1.5. Keep the resultant of the oil pressures inside the kern area of the footing if possible (Not required, but is a best practice - soil bearing may go critical quickly if outside the kern).

Mike McCann
MMC Engineering

 

[Duwe6]

And you might want to look at the possibility buckling, both when the horiz tank is half-full and full. With a horiz tank on the usual two saddles, buckling during vertical displacement is not trivial. IIRC, at the Callaway nuke in MO, the vertical design seismic load was right at +1G.