Crane Lift - Rectangular Tank

[oilcivil]

Hey Gang,

I posted a while back about rectangular tank design and found some very good resources. Thanks to everyone that helps. I can provide some research papers for anyone interested.

Anyway, now I'm analyzing the tank for a crane lift. The tank will have four lifting eyes and I want to do a check to see how it will perform when lifted full of water (probably a very conservative scenario) Anyway there is not alot of information out there. I have checked the lifting eyes and welds for tension, bending and shear failure. There are three 'W' beams across the bottom that I will check for sag/deflection when lifted.
Beyond that I'm not sure what to check, is there anyhthing I'm missing. Remember all of the side plates are designed.
Should I check for shear in the corner welds?


Thanks, in advance

 

[chicopee]

I don't know how big you tank is but what in the world would you have a lift with a tank full of water?

Make sure that the load is 50% of the crane can lift for the boom length and load radius which you anticipate at the site.

 

[MJCronin]

Suggest that you use spreader beams (strongbacks) to prevent bending/compression loads in the tank rim

 

[JohnGP]

I agree totally with above responses. I have never seen a tank designed to be lifted full of water. At the very worst you may need to allow for some water in the bottom if, for example, it's an open top tank that can get rained on during transport, and the drain is not from the bottom (but even then that's a stretch and can be mitigated!).

For a totally vertical lift at the lifting points, use one of MJCronin's spreader beams at each end of the tank, with another over the top of those two.

Cheers,
John

 

[oilcivil]

If I am using just one spreader beam to hold the cables apart (cables come down from boom, then 'V' out with spreader) is the K value in the spreader beam considered to be pinned/pinned and therefore 1?

 

[weab]

Looks like pinned-pinned to me - no end moment capacity. Use K = 1.0 .