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Re: Partially rigid connection design

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>Lets us help one another to find practical solutions to engineering
>problems, not by ignoring them and not by blaming each other
I'll field this one, since I daresay my comments were taken as criticism. 
First, I don't think anyone means to ignore the need for sound connection 
design. My own experience is that connections fail far more often than 
the connected members. There's also a lot of misunderstanding floating 
around how connections of all sorts behave. I've run into engineers who 
thought the way to design moment out of a connection was to assume pin 
ends in the finite element model and the devil take the relative 
displacement. Applying sound engineering practice to connections is no 
waste of time.

That said, let's not mistake the ability to include elastic support in a 
finite element model for understanding of the behavior of real 
connections. That's as big a mistake as disposing of moments by assuming 
pin ends. FEA, especially to us kicked into the real world armed only 
with relaxation methods and a slide rule, gives a wonderful ability to 
juggle structural variables, the dark side of which is an unwarranted 
assumption that numerical precision equates to control over the physics 
involved.

Luo hasn't posted much since the tabulation of end loads last week, and I 
hope he wasn't put off by the response. There's nothing wrong with 
innovative approaches, only techniques that can't stand up to serious 
questioning. 



Christopher Wright P.E.    |"They couldn't hit an elephant from
chrisw(--nospam--at)skypoint.com        | this distance"   (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)
http://www.skypoint.com/~chrisw