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RE: Reinforcing for a Metal Building Slab...(Harold)

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Thanks for the reply. I have a copy of the guideline you mentioned in
addition to "Metal Building Systems" that Gary mentioned and have been using
"first principles" as discussed which, as you say, makes the most sense and
avoids the "code moguls". I suppose my question was intended to see if
anyone (for whatever reason) was applying Section 1907.12 to a slab-on-grade
in Seismic Zones 3 & 4 and using a minimum amount of reinforcing specified
from there, even though analysis of all points may show that reinforcing
below the minimums in that section would suffice.

I agree with your summary. Again, I was curious to see if anyone felt that
Section 1907.12 applies (I don't believe it does, as you've also stated).


-----Original Message-----
From: Sprague, Harold O. [mailto:SpragueHO(--nospam--at)]
Sent: Tuesday, October 03, 2000 9:06 AM
To: seaint(--nospam--at)
Subject: RE: Reinforcing for a Metal Building System Slab-on-Grade


There was a guideline that was developed for Butler Manufacturing called
"Foundation Design and Construction Manual".  It was developed by the people
at Computerized Structural Design, Inc. They developed a methodology that
given a thrust magnitude calculates the length of hairpin required for a
given mesh.  You have to transfer the forces from the hairpins into the
mesh.  The mesh then either uses the slab in friction to resist the thrust
or ties the 3 hinged arch together.

The UBC 1907.12 values are for slab shrinkage only, and have nothing to do
with the applied lateral thrust.

There is no real code guidance here.  You will just have to use first
principles.  You will have to develop the reinforcing required based on
acceptable performance (crack acceptability), and calculate the flexural
reinforcing, the temperature / shrinkage reinforcing, and the reinforcing
required to develop the thrust in the hairpins.

Engineering unencumbered by the whims of code moguls.

Harold Sprague

	-----Original Message-----
	From:	Dave Adams [SMTP:davea(--nospam--at)]
	Sent:	Friday, September 29, 2000 5:55 PM
	To:	seaint(--nospam--at)
	Subject:	Reinforcing for a Metal Building System

	Hello all,

	I apologize if this is a discussion that has been brought up before.

	What minimum amount of reinforcing meets Code requirements when
hairpins are
	present in a slab-on-grade with, perhaps, fork lift traffic but no
	storage rack leg loads? It seems that it would be appropriate to at
	provide enough steel required to transfer the hairpin forces and tie
	everything together (possible unequal distribution of support for
	loads, etc.), but is there a need to consider the minimums per
	1907.12 as applicable?

	This may be one of those "bonehead" questions, but I'd like to know
what the
	consensus is (if there is one).

	Dave K. Adams, S.E.
	Lane Engineers, Inc.