equipment skid C.O.G.

[LearnerN]

When designing a structural steel skid to support piping and valves, what rule of thumb should guide how far off from the center of the skid the fully-assembled-skid C.O.G. should be allowed for safe lifting of the fully assembled skid during construction?

In the past, I've typically just made sure the C.O.G. was like in the middle third of the skid...AND...made sure all the reactions at the lifting lugs were as close to each other in load/force experienced as possible, as well as making sure the loads were not too high for each lifting lug's capacity.

Thank you!

 

[atrizzy]

Middle third is a pretty good rule to follow. When using a rectangular shaped footing with a triangular soil pressure distribution, when the eccentricity = the length of the footing/6 (placed in the middle third) this keeps the heel of the footing from uplifting.