] [Thread] [Date] [Author]

[Lew Midlam <Lew.Midlam(--nospam--at)lcm.com>]

ACI has a paperback book (I can't find my copy, but I think it's titled "Design
of Foundations for Machinery" - ornage, white & blue cover) which is a
collection of papers on this subject.

I would be very cautious of any rule-of-thumb.  These are often provided by the
equipment manufacturer, and will get you in the ball park, but you really should
do a dynamic analysis if you're concerned about vibration of nearby equipment or
buildings.  You'll need a soils report (be sure to tell the geotechnical
engineer what parameters you need - see the ACI book) and the equipment's
dynamic data - such as  max. angular momentum, & acceleration vs. frequency,
etc.

Also, don't forget to do a seismic overturning analysis if Greensboro is in a
seismic zone other than 0.

Lew Midlam, PE
www.lcm.com
=========================

Theodore H. Partrick, Jr. wrote:

> I think I remember seeing on this list a long time ago some discussion of
> isolated slabs used for equipment support. These slabs are usually on the
> order of 24" thick for generator pads under 10,000 lb generators, something
> on the order of four times the equipmtent weight.
>
> For a 20,000 pound diesel generator, 1800 rpm at rated load, would a
> reasonable approach for isolation and support be a slab of 80,000 pounds
> (24" x 12' x 24')? Vibration isolation is not so much for human comfort,
> just don't want to shake the building (1 story masonry, reinforced) and
> contents apart.
>
> Is a rule of thumb applicable for such equipment support? I have struck out
> in my own library.
>
> Any support would appreciated.
>
> Ted Partrick, PE
> City of Greensboro (Greensboro, NC)
>