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# RE: 1997 NDS Equation Error?

• To: "'seaint(--nospam--at)seaint.org'" <seaint(--nospam--at)seaint.org>
• Subject: RE: 1997 NDS Equation Error?
• Date: Tue, 13 Nov 2001 11:21:17 -0800

```Mark Swigle wrote:
***
First a moot point: Using your numbers above, you should have gotten 2100
lbs for Ziiim, not 3156 lbs.
***

Not a moot point Mark. Thanks for pointing out the error. I messed up
transposing my spreadsheet to calc one bolt size to calculate all bolt sizes
at once.

***
Second, I have always used the version in the 1994 UBC, where the term in
question (in the formula for k1) is shown *outside* the radical.  Using the
formulas that way, my numbers always agree with the tables in the 1994 UBC.
***

Outside the radical is correct. I looked in my Breyer Book, design of wood
structures, and I see I had crossed out the extent of the radical for k1...
apparently, I had noticed this before.

***
Third, you should use Fem=Fes=5600 psi, not Fem=6000 psi, for
wood-to-concrete connections.  At least that was the way in the 1991 NDS and
the 1994 UBC.  I realize that AF&PA's Technical Report 12 shows that the NDS
tables are based on Fe=6000 psi for concrete, but I don't know if the new
NDS tables have been updated for this.  Let's stick to the old way for now
(for purposes of this message, that is).
***

The 97 UBC still says to use the double shear value of twice the thickness
of the side member with Fem=Fes based on wood to wood. The 97 NDS, says,
single shear, Fem=6000 psi for (2000 psi concrete - other values for other
strengths of concrete not given), tm=6" min. Yes it is different and the 97
NDS tables are correct and that is actually where the Fem and tm values are
given.

-gerard
SJ, CA

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