Excess stress at bottom

[farzam]

Hi All,

We have floating roof tank(ID=40m) and to repair tank foundation we have to use jack to uplift tank.Regarding our calculation stress at bottom is more thanl Allowable stress but less than yeild stress.may I have your idea that this has any problem for tank or should we do another thing?(roof is located on the bottom)

Thanks in Advance
Farzam

 

[Elrae]

farzam,

We do a lot of tank jacking for foundation repair and many of the tanks have floating roofs. In every case, we jack and support the floating roof from the shell and cribbing off the bottom well away from the corner weld. We will also support off columns if they are available. I am speaking primarily of steel floating roofs here. Getting the floating roof off the bottom near the shell should allow you to jack the tank shell, repair the foundation, and release the tank shell back to it's original location without much stress at the corner weld. For extra assurance, you may want to vacuum box test the corner weld after a good visual is performed.

Best of luck