Dynamic Equipment Anchorage - ACI 351.3

[smb4050]

I need to design a stand and anchorage for a centifuge in an animal rendering facility. I observed an existing installation, and there was a lot of lateral movement, but the stand was not well braced. Centifuge total weight is 4,600lbs of which 1,000lbs is rotating at 115rpm. The centrifuge will be mounted on a stainless steel frame (300lbs) which will be anchored to an existing 12" concrete slab-on-grade. The rotating center-of-mass is 60" above the anchorage. Rotating cycles is in the range of 8 million/year. I'm using ACI 351.3 to determine design force as the manufacturer hasn't provided an unbalanced design load. Equation 3-7 gives an unbalanced force of 19.2lbs which seems real low. My question is has anyone else used this reference to design a similar installation, or know of other references/values to use to determine a horizontal design load? I'm considering using a horizontal force based on overturning moment (2,500lbs), but that seems overly excessive. Secondary question, is the use of epoxy post installed anchors with a grouted base plate resonable? Thanks,

 

[WARose]

I haven’t used that reference for that particular purpose…..but using my own sources, I actually came out with less unbalanced force (i.e. about 12 lbs; and that is with an assumed eccentricity of 0.032”). So looks like you are probably in the ballpark.

As far as your second question goes: I’m not sure I have used post-installed anchors for this purpose…..but I seem to remember Hilti offering some guidelines in that regard. Typically I have used Rowan anchor bolts for dynamic loads (but that has typically been for more heavy duty stuff like compressors).