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Re: Leveling Nuts

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> From: "John L. Smart" <smartj(--nospam--at)smartengineers.com>

> I have a plan reviewer telling me that if I allow leveling nuts, I must
> specify that the column be leveled, shimmed, then the leveling nuts backed
> off before grouting. The erectors I have asked have never heard of this. Has
> anyone else? I assume the point is to keep the column from sitting on the
> bolts, but so what?

I have heard this pondered before. The concern is that the bolts will
support an inordinate amount of the bearing force. Can't happen with any
normal, fully grouted base plate. I have never heard anyone attribute a
failure to leveling bolts.

If the base was perfectly rigid (which it's not) it would be a
significant issue (which, apparently, it's not).

In reality, the column is loaded and bears against grout and bolts at
the same time. The grout bears in compression over a large area but the
plate is bending at the bolts, so, the grout takes the load, just as it
should. At MAX, similar pressure is passed down through the bolt into
the concrete. No exceptional loads anywhwere.

There is no need to back off the leveling nuts.

-- 
R. Paul Ransom, P. Eng.
Civil/Structural/Project/International
Burlington, Ontario, Canada
<mailto:ado26(--nospam--at)hwcn.org> <http://www.hwcn.org/~ad026/civil.html>

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