But realise that an unbalanced load on those 17x17 base plates would
only have to have the CG 8-1/2 inches to one end of the centerline of
the base plate to place a load varying from 40 psi at the one end to 0
psi at the other. Just a little further and the concrete at one end
goes into tension, which it likes very little. The concrete won't
fail in compression, but in tension and torsion. I'm not a civil
engineer, but I'd check with one before loading a vehicle onto such a
> Date: Wed, 20 Aug 2003 19:06:39 -0600
> From: Dave & Marlene <firstname.lastname@example.org>
> I agree with Derek on the pad height definition. As for the needed
> concrete thickness, with the two 17 inch square base plates & a total
> weight of 11,325 pounds (lift weight plus max capacity) there would only
> be about 20 pounds per square inch load on the concrete floor. If there
> were only one 17 x 17 base plate the load would still only be 40 psi.
> For a comparison, a 8,000 pound vehicle sitting on a four by four inch
> tire contact patch would apply about 125 pounds per square inch to the
> concrete. A four inch slab should be more than adequate.
> Dave Russell
> Derek wrote:
> > Wayne
> > The specs on the web page you reference state -
> > - "Minimum pad height 4"/102mm"
> > Isn't that the minimum height of the steel arms (and pads)
> > that need to go under the vehicle before lifting?
> > I don't think there is any concrete "pad" spec called put -
> > at least not on that page. I agree that 4" concrete seems
> > too little - but I'm not a concrete engineer.
> > Derek
> > --- Wayne Farrington <email@example.com> wrote:
> >>Well, I've come to the end of my rope regarding not
> >>having a lift in my shop,
> >>so I'm going to buy one. Thinking about this one:
> > http://www.gesforless.com/product_info.isg?products_id=343
> >>Anybody have this model? The specs call for a 4" minimum
> >>slab. My shop has a
> >>~4" slab but that seems awfully thin for a 10K lift? I
> >>will be lifting my 3/4
> >>ton ext. cab pickup with this thing. It looks like there
> >>is already a "stress"
> >>crack in the concrete running near the area where the
> >>base plate will be
> >>bolted down. How hard is it to pour a thicker flush pad
> >>within the existing 4"
> >>slab? How do I "connect" the thick pad with the existing
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