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RE: 1997 NDS Equation Error?

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Nels:


I think that Table 8.2A agrees with the 8.2.1 and uses k1 =
[sqrt{Re+2*(Re^2)*(1+Rt+Rt^2)+(Rt^2)*(Re^3)}-Re*(1+Rt)]/(1+Re), that is with
-Re*(1+Rt) outside the squareroot the way it is written in the NDS. 

However; with -Re*(1+Rt) outside the squareroot amd for a 3" DFL [Fe=5600
psi] main member with 1.5" DFL side member, mode II controls with Z=1387 and
the NDS Table 8.2A has Z=1390.  

For a 3.5" DFL main member with 1.5" DFL side member mode IIIs controlls
with Z=1590 like NDS Table 8.2A.


Respectfully,

Scott M Haan P.E.
Plan Review Engineer
Building Safety Division 
Development Services Department
Municipality of Anchorage
http://www.muni.org/building
phone:907-343-8183  
fax:907-249-7399
mailto:haansm(--nospam--at)ci.anchorage.ak.us



-----Original Message-----
From: Nels Roselund, SE [mailto:njineer(--nospam--at)att.net]
Sent: Thursday, November 08, 2001 1:40 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: 1997 NDS Equation Error?


Gerard,

I have a mathcad worksheet for the mudsill-concrete single shear bolt
computation per NDS Section 8.2.3.

For each bolt size, 1/2" to 1", mode IIIs controls and agrees with Table
8.2E.

k1 does not enter the computation for mode IIIs.

If you have mathcad, let me know.  I'll email you my active worksheet [at
least I'll give it a try] -- you can check my formula
entries, and you can enter various bolt sizes and see the results.

If you don't have mathcad, let me know, and I'll send you a pdf file so you
can at least check my entries.

I've stopped expressing my complaints about the NDS connector formulas, but
I guess now is a good time to let it out one more time: the formulas are not
intuitive, and you have to take them without comprehending them.  There is
no way, that I can see, to understand the significance of a k-number in a
yield-mode formula.  It's there because the book says it's there.  Grrrrr!
I'd like to have a feel for what a number that I'm using means.

Nels Roselund
Structural Engineer
South San Gabriel, CA
njineer(--nospam--at)att.net




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