center of gravity vs foot print 1

[dtharrett]

We have a machine with a rather high center of gravity basically sitting on 4 tall legs. I seem to recall some safety guildlines or industry standards that provided guildlines for safe center of gravity height vs footprint ratios but cannot seem to put my hands on that document. Can someone point me in the correct direction? FWIW, the machine is considered static.
Thanks

 

[drawoh]

dtharrett,

I asked this question in the structural forum.

thread507-255357

--
JHG

 

[Cockroach]

Over turning moment in stability of the structure, truss, etc.

Regards,
Cockroach

 

[dhengr]

Dtharrett:
Take the gravity load vector through the CG as one loading; and a lateral load vector through the CG, what ever that might be, from wind, EQ or some other lateral load; project the resultant of these two loads to the base/slab, and if it touches the ground within the box formed by the four legs, it is technically stable. You factor the loads for your own safety liking, etc. EQ lateral loads act at the CG (center of mass), other lateral loads may have to be converted to act at the CG, assuming either load produces the same lateral moment about the base. In either case you are just summing the moments about the legs; the gravity load (DL only) acting as a righting moment; while the lateral load produces an overturning moment, which must always be smaller than the lightest righting moment.

 

[zekeman]

"We have a machine with a rather high center of gravity basically sitting on 4 tall legs. I seem to recall some safety guildlines or industry standards that provided guildlines for safe center of gravity height vs footprint ratios but cannot seem to put my hands on that document. Can someone point me in the correct direction? FWIW, the machine is considered static."

Why would you need a document to solve such a straightforward problem.
Just enter the force vectors that make sense, including wind snowload, gravity,etc and do the grunt work to find the structural stress on the members after adding a fair factor of safety. That's what engineers do.